Category Archives: Uncategorized

Fall 2017

Issue 10 (3), 2017

Foot anthropometrics in individuals with diabetes compared with the general Swedish population: Implications for shoe design
by Ulla Hellstrand Tang , Jacqueline Siegenthaler, Kerstin Hagberg, Jon Karlsson, Roy Tranberg

Osteochondromas of the subtalar joint: A case study
by Christopher Gaunder MD, Brandon McKinney DO, Joseph Alderete MD, Thomas Dowd MD

Divergent Lisfranc injury with dislocation of great toe interphalangeal joint: A rare case report
by Dr. Ganesh Singh Dharmshaktu, Dr. Binit Singh

Charcot foot management using MASS posture foot orthotics: A case study
by Edward S. Glaser DPM; David Fleming BS

Surgical treatment of a large plexiform neurofibroma of the lower extremity
by Jacob Jensen, David Shofler, Della Bennett

Staged surgical intervention in the treatment of septic ankle arthritis with autologous circular pillar fibula augmentation: A case report
by Sham J. Persaud DPM, MS; Colin Zdenek DPM; Alan R. Catanzariti DPM

Summer 2017

Issue 10 (2), 2017

Isolated, nondisplaced medial cuneiform fractures: Report of two cases
by Koun Yamauchi MD, Satoru Miyake MD, Chisato Kato MD, Takayuki Kato MD

Radiographic changes in coronal alignment of the ankle joint immediately after primary total knee arthroplasty for varus knee osteoarthritis
by Ichiro Tonogai, Daisuke Hamada, Koichi Sairyo

Trigger events for Charcot neuroarthropathy: A retrospective review
by Brent H. Bernstein DPM FACFAS, Payel Ghosh DPM, Colleen Law DPM, Danielle Seiler DPM, Thuyhien Vu DPM

The D-Foot, for prosthetists and orthotists, a new eHealth tool useful in useful in risk classification and foot assessment in diabetes
by Ulla Hellstrand Tang BSc, Roy Tranberg PhD, Roland Zügner BSc, Jon Karlsson MD PhD, Vera Lisovskaja PhD, Jacqueline Siegenthaler BSc, Kerstin Hagberg PhD

Effects of medial and lateral orthoses on Achilles tendon kinetics during running
by Gareth Shadwell, Jonathan Sinclair

Isolated, nondisplaced medial cuneiform fractures: Report of two cases

by Koun Yamauchi MD1*, Satoru Miyake MD1, Chisato Kato MD1, Takayuki Kato MD1

The Foot and Ankle Online Journal 10 (2): 1

Isolated, nondisplaced medial cuneiform fractures are difficult to diagnose using plain radiographs. Computed tomography (CT) or magnetic resonance imaging (MRI) are necessary to aid in diagnosis. This paper describes two patients with this fracture that were more difficult to suspect because the fractures occurred during running, which are extremely rare. Tenderness and swelling around the medial cuneiform was observed that led to suspicion of a fracture; this lead us to perform a CT scan or MRI for confirming the presence of the fracture. However, tenderness and swelling around the midfoot can be observed in a patient with a sprain without the fracture. Therefore, it is more important to note that isolated, nondisplaced medial cuneiform fracture can be induced by an indirect force such as that occurring while running.

Keywords isolated medial cuneiform fractures, non-displaced, during running, computed tomography, magnetic resonance imaging

ISSN 1941-6806
doi: 10.3827/faoj.2017.1002.0001

1 – Department of orthopedic surgery, Akita Hospital, Takara, Chiryu City, Aichi 472-0056, Japan.
*Corresponding author: Koun Yamauchi,

Here, we describe two consecutive patients with isolated, nondisplaced medial cuneiform fractures that occurred during running. Cuneiform fractures generally occurs along with other fractures of the midfoot, such as Lisfranc dislocation fractures, whereas the occurrence of isolated medial cuneiform fracture is rare. A total of only seven published case reports have been reported in the literature [1-5]. Nevertheless, an isolated, non-displaced fracture of the medial cuneiform may be easily suspected when the midfoot has been bruised by a direct, intense force, such as the impact of a traffic accident. However, it may be more difficult to suspect the fracture when being caused by indirect and acute force. Only one case report clearly describes the mechanism of isolated, nondisplaced medial cuneiform fracture being caused by indirect and acute force that occurred during dancing [4]. Therefore, the occurrence of isolated medial cuneiform fracture during running is extremely rare.

Case Report #1

A 25-year-old woman visited a hospital after hearing a cracking sound and feeling pain in her right midfoot during short-distance running at full speed in a park. Clinicians at the hospital diagnosed her injury as a sprain because they found no indications of fracture. Two days later, she visited our hospital with tenderness and swelling around the midfoot. However, radiograph of the midfoot showed no indications of a fracture (Figure 1), and we diagnosed her injury as a sprain.

Figure 1 Plain radiographs of the foot in first case. White arrows show cuneiform bone. (a) anterior–posterior image; (b) lateral–medial image; (c) oblique, lateral–medial image; and (d) oblique, medial–lateral image.

Five days later, she came for an examination; the tenderness and swelling around the midfoot persisted, although the spontaneous pain was gradually decreasing. We performed a computed tomography (CT) scan, which indicated an isolated, nondisplaced medial cuneiform fracture (Figure 2).

Figure 2 Computed tomography of the foot in the first patient. White arrows show fracture line. Dotted lines in axial image (a) show reference lines for coronal image (b) and sagittal image (c).

Her treatment included non weight-bearing (NWB) activity for two weeks without any immobilization. An arch support was applied on her right foot. Partial weight-bearing (PWB) activity was allowed from the fourth week after the injury, full weight-bearing (FWB) activity was allowed from the sixth week after the injury, and she was treated in rehabilitation from the fourth week to three months after the injury. At two months after injury, her hallux range of motion (ROM) recovered to the level of the contralateral side hallux ROM; however, swelling around the midfoot persisted but disappeared at three months after injury. We conducted a self-score, self-administered foot evaluation questionnaire (SAFE-Q) at two and three months after the injury [6]. The following were the scores at two and three months after injury, respectively: Pain scores: 54.1 and 76.4; activities of daily living (ADL) scores: 65.9 and 91.0; social functioning scores: 0.4 and 82.5; shoe-related scores: 41.7 and 91.7; and general health scores: 60 and 90.0 (Full score for each subscale was 100 points).

Case Report #2

A 35-year-old woman presented at our hospital with tenderness and swelling around the midfoot. She had felt sharp pain in her right midfoot as she dashed up an acute slope. Radiographs taken during first examination showed no indication of a fracture (Figure 3), but CT scan showed an isolated, nondisplaced medial cuneiform fracture (Figure 4). Furthermore, magnetic resonance imaging (MRI) showed an acute fracture of the medial cuneiform (Figure 5).

Figure 3 Plain radiographs of the foot in second patient. White arrows show cuneiform bone. (a) anterior–posterior image; (b) lateral–medial image; (c) oblique, lateral–medial image; and (d) oblique, medial–lateral image.

Figure 4 Computed tomography of the foot in the second patient. White arrows show fracture line. Dotted lines in axial image (a) show reference lines for coronal image (b) and sagittal image (c).

Figure 5 Magnetic resonance imaging (MRI) of the foot in the second patient. White arrows show fracture area in coronal images of T1-weighted image (a), T2-weighted image (b), and T2-weighted image with fat saturation sequence (c).

Her treatment included NWB activity for three weeks and immobilization with a soft-splint because of significant swelling. At three weeks after the injury, we started the same treatment strategy as that with the first patient. At two months after injury, her hallux ROM had recovered to the level of contralateral side hallux ROM, and swelling around the midfoot was no longer apparent. SAFE-Q scoring was conducted at 2, 3, and 8 months after injury. Following were the scores at 2, 3, and 8 months after injury, respectively: Pain scores: 76.7, 91.4, and 99.9; ADL scores: 75.0, 93.2, and 97.7; social functioning scores: 83.3, 82.4, and 100; shoe-related scores: 83.3, 58.3, and 91.7; and general health scores: 80, 90.0, and 100.


Similar to earlier reports on diagnosis and treatment of an isolated, non-displaced medial cuneiform fracture [1-5], we were not able to diagnose the fracture in either of our patients based on the plain radiographs alone. All authors have reported that it was difficult to diagnose an isolated, non-displaced medial cuneiform fracture using plain radiographs and that CT and MRI were necessary to diagnose this fracture.

Observed tenderness and swelling around the medial cuneiform bone lead to suspicion of a fracture; this lead us to perform a CT scan or an MRI for confirming the presence of the fracture. An isolated, non-displaced fracture of the medial cuneiform may be easily suspected when the midfoot has been bruised by a direct, intense force, such as the impact of a traffic accident, whereas the stress fracture of this bone can be suspected when the feet of athletes are subjected to repetitive, physical loads. However, when the midfoot is subjected to indirect and acute one-time force, such as dancing or running, clinicians may not perform a CT scan or MRI because they generally do not suspect the occurrence of a fracture, thereby diagnosing the tenderness and swelling around the midfoot as a sprain and/or bruise. Therefore, our suspicion of the isolated, nondisplaced medial cuneiform fracture is noteworthy even when the patient’s midfoot has been subjected to indirect and acute one-time force during running. Although the bipartition of the medial cuneiform was not observed in both our patients, a clinician should suspect the presence of midfoot pain related to the bipartition of the medial cuneiform bone as a differential diagnosis. Steen et al [7] proposed that the bipartition of the medial cuneiform can be associated with midfoot pain following an acute injury.

As reported in the earlier reports, treatment for isolated, nondisplaced medial cuneiform fracture can be conservative [3, 5]. In both of our patients, CT scan taken at five weeks after injury exhibited bony union without complications, such as malunion or displacement. Although the patient’s hallux ROM showed recovery two months after injury, SAFE-Q scores remained unfavorable. In particular, SAFE-Q scores of the first patient were worse, which could have resulted from persistent swelling around her midfoot. At three months after injury, the SAFE-Q scores were better in both patients, except the shoe-related scores of the second patient. We were not able to ascertain any causes for the low shoe-related scores in the second patient. At eight months after injury, the SAFE-Q scores were almost full scores in the second patient, while the SAFE-Q scores were not conducted in the first patient.

Interestingly, CT scan exhibited a similar fracture type in both patients: dorsal and plantar bone fragment with avulsion fracture of the lateral–distal–plantar cortex. Because the fractures in both patients included joint surfaces (navicular–cuneiform joint and cuneiform–metatarsal joint), bone fragment displacement was contraindicated. Therefore, surgery using embedded screws may be an appropriate treatment option for fixation of dorsal and plantar bone fragments. Surgery, such as definitive fixation, is likely to maintain non-displacement until bony union is achieved. Definitive fixation is particularly appropriate for athletes because it enables early and successful recovery (because athletes are able to actively return to their respective sports sooner) compared to conservative treatment. We strongly suggest that more study is needed to assess the effect of surgical treatment options on recovery after isolated, nondisplaced medial cuneiform fracture.


Isolated medial cuneiform fracture can be induced by an indirect force while running and should be diagnosed by CT and MRI.


Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent:  Informed consent was obtained from all individual participants included in the study.

Funding declaration and Conflict of Interest:  This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. There are no conflicts of interest to declare.


  1. Olson RC, Mendicino SS, Rockett MS. Isolated medial cuneiform fracture: review of the literature and report of two cases. Foot Ankle Int 2000;21(2):150-153. (PubMed)
  2. Taylor SF, Heidenreich D. Isolated medial cuneiform fracture: a special forces soldier with a rare injury. South Med J 2008;101(8):848-849. (PubMed)
  3. Guler F, Baz AB, Turan A, Kose O, Akalin S. Isolated medial cuneiform fractures: report of two cases and review of the literature. Foot Ankle Spec 2011;306–309. (PubMed)
  4. Liszka H, Gadek A. Isolated bilateral medial cuneiform fracture: a case report. Przegl Lek 2012;69(9):708-710. (PubMed)
  5. Eraslan A, Ozyurek S, Erol B, Ercan E. Isolated medial cuneiform fracture: a commonly missed fracture. BMJ Case Rep 2013;22:2013. (PubMed)
  6. Niki H, Tatsunami S, Haraguchi N, Aoki T, Okuda R, Suda Y. Validity and reliability of a self-administered foot evaluation questionnaire (SAFE-Q). J Orthop Sci 2013;18(2):298-320. (PubMed)
  7. Steen EF, Brancheau SP, Nguyen T, Jones MD, Schade VL. Symptomatic bipartite medial cuneiform: report of five cases and review of the literature. Foot Ankle Spec. 2016;Feb;9(1):69-78. (PubMed)



Spring 2017

Issue 10 (1), 2017

Small-vessel vasculitis: A review and case report
by Kinna A. Patel, DPM

Retained foreign body in the foot presenting as tenosynovitis of the flexor digitorum longus tendon
by Muhammad Haseeb, Muhammad Farooq Butt, Khurshid Ahmad Bhat

Clinical clearing of moderate and severe onychomycosis with the Nd:YAG 1064nm laser and post treatment prevention with tolnaftate
by Myron A. Bodman DPM, Marie Mantini Blazer DPM, Bryan D. Caldwell DPM, Rachel E. Johnson DPM

Raynaud’s-like symptoms induced by prescription medication
by Robert L. van Brederode, DPM, FACFAS

Temporary bridge plating of the medial column in Chopart and Lisfranc injuries
by Alaa Mansour DPM, Lawrence Fallat DPM, FACFAS

A unique presentation of recurrent cavus foot of an adolescent patient with Marfan syndrome: A case report
by Kaitlyn L. Ward DPM, Philip R. Yearian DPM, FACFAS

Letter to the Editor – Response
by Edward S Glaser and David Fleming

Letter to the Editor – Response

by Edward S Glaser1 and David Fleming2*

1 – Founder and CEO of Sole Supports, Inc.
2 – Sole Supports, Inc.
* – Correspondence:

Response to Letter to the Editor regarding MASS Posture Article

Dear Sir,

We read Dr. Phillips letter regarding our article Foot Posture Biomechanics and MASS Theory in the November issue with careful regard. While our article had some defects the acts were not as egregious as they were made out to be. The letter was structured well with numbered questions in three different sections, and we would like to address them as such.

The first section addresses “some of the outright misstatements about the theories of Merton L. Root”

  1. We would like to thank Dr. Phillips for the scholarly references showing that our statement in the article is supported by some of the greatest minds in foot biomechanics, and is consistent with others who have been looking. We would like to thank Dr. Phillips for the historical correction regarding giving Root credit for making the observation that rearfoot varus predominates when the patient is in prone and held in “neutral” position.
  2. We chose the 17 measurements because they were the ones Dr. Phillips and Kevin Kirby showed had horrible inter-rater reliability. “Static” refers to the fact that the body is static on the treatment table as opposed to a dynamic study where the patient is walking, running, turning, jumping etc. The line “Root recommended taking 17 measurements called the Static Biomechanical Exam” should be edited to “Root recommended taking 17 measurements, now called the Static Biomechanical Exam” we apologize for the error.
  3. This is not only what Dr. Glaser was taught at NYCPM as Root biomechanics, but is a direct correlation between the biomechanical examination and the design of the orthotic. Measure 4 degrees of rearfoot varus and put a 4 degree post. This presumes 100% efficiency of the part of the orthotic and the foot, which is a physics impossibility. If treatment was aimed at stabilizing the midtarsal joint, it failed. This is due to the foot will collapsing its posture until something stops it. Much like John Weed’s seven theorems (allow us to credit Weed here although we know there were other authors) states that if the calcaneus everts more than 2 degrees, the heel will fall through into full pronation (with associated calcaneal eversion). By the time the midtarsal joint touches the orthotic, the pronation is almost complete; the foot is already in a collapsed posture. It was precisely because of the rigid materials Root chose (remember, he was a lab owner, like Dr. Glaser) he had to lower the arch to make the orthotics tolerable. However, as for the forefoot post, we would like to thank Dr. Phillips for the historical clarity he has provided and by pointing out that we gave to much credit to Root regarding therapeutic significance to forefoot posting. We were not trying to give a complete and accurate time line of Root’s life and discoveries, instead our purpose was to offer the practitioner an alternative paradigm to base their biomechanical decision making, backed by observation, physics, and patient outcomes.
  4. Dr. Phillips states that we made an accurate statement. The rest of the objections are difficult to tie in to that statement. Root’s other “neutral” positions are off topic, of course there are other joints in the foot. Many axes dictate the posture of the foot. All except the Subtalar joint are addressed in Root’s corrective device. Root surely knew of all the axes of the foot that influence posture, but he failed to address the postural collapse in his orthotic.
  5. We would like to thank Dr. Phillips for expanding on our statement, we see no misrepresentation.
  6. A.) In Lee’s article, Root describes the epiphany in the shower when he came up with neutral subtalar joint position and describes it as “the key to my being able to contribute to podiatry.” Kirby also choose the sub talar joint axis “…during many weightbearing motions, the foot can be effectively modeled as a rigid body with the calcaneus, cuboid, and navicular all rotating as a single unit around the talus at the subtalar joint axis”

Lee, W. E. (2001). Podiatric biomechanics. An historical appraisal and discussion of the Root model as a clinical system of approach in the present context of theoretical uncertainty. Clinics in podiatric medicine and surgery,18(4), 564.

Kirby, K. A. (2001). Subtalar joint axis location and rotational equilibrium theory of foot function. Journal of the American Podiatric Medical Association91(9), 470.

  1. B.) There are no relevant comments for this statement.
  2. C.) Allow a clarification, by “partially pronated” we are using MASS posture as a reference. We are stating that STJ neutral is approximately 1/3 pronated from MASS posture, which is the beginning of postural collapse. The rest of your comments are predicated on this misunderstanding.

The second section address, “some of the poor representation of the literature used to support the authors’ contentions that the theories of Root should be discarded.”

  1. Dr. Phillips states that they discarded Elftman’s theory prior to 1977, but it is stated in Root’s book, Normal and Abnormal Function of the Foot – Clinical Biomechanics Volume II, on page 80.
  2. Where the body’s momentum intersects the transverse plane of the sub talar joint, the joint has nothing to do with the fact that the force vector intersects the sub talar joint axis. Frictional moments are far more significant around the heel rocker axis than the sub talar joint axis. Hence the calcaneus “hits the ground in forward rolling motion.” Southerland’s seven theorems starts.
  3. We would like to thank Dr. Phillips for the historical information.
  4. In no way are we making the assumption that all ADLs require the same amount of pronation or supination. We are simply stating that, since every step is different and applies a different force. Therefore, one must look at a range of forces when performing calibration.
  5. Dr. Phillips is absolutely correct. Here is a link to the video:
  6. Dr. Phillips is correct, the references were double referenced, and Higbie was misspelled. Higbie et al had already tested almost every large central fabrication US custom orthotic laboratory and found that PAL’s orthotic as described made the greatest positive kinematic change. PAL was therefore selected so as to represent the best functioning Rootian orthoses on the market in 1999. According to actual data collected. If they had chosen a more representative Rootian orthotic the results would have shown even more difference.

The final section address, “ways the authors make outlandish assumptions, demonstrate poor reasoning, and write what can be best called “mechano-babble”.”

  1. The middle facet is on a shelf of bone that protrudes medially, the Sustentaculum tali. The middle facet would have negligible effect here regardless of its relative surface area. When there is no anterior facet there is considerable potential for hyper-pronation unless ligament strength is exceptional. The more vertical the STJ axis, the greater the torque will be applied by transverse plane rotation of the tibia. Who is measuring in the frontal plane only? Is this a criticism of Root? Dr. Phillips’ description of torque during propulsion is exactly what would happen if the foot was in an ideal posture. He is advocating that we should put the foot in its best posture for propulsion. We are also in full agreement that ligamentous strain is occurring when the posture collapses and are therefore attempting a simple, elegant solution. Thank you for pointing out the dangers of allowing the foot to collapse its posture.
  2. We are sorry that Dr. Phillips finds fault with Hammel’s study. We are not sure any of the authors are much different in their analysis of STJ motion even though most used skin markers to assist interosseous STJ motion analysis. Then Dr. Phillips goes on to state that Root agrees with us on everything. Dr. Phillips’ description is accurate and we agree with it. His statement does not disagree in any way with MASS Posture theory. Your description and Roots are sequentially the same as we described. Root states a slight amount of STJ rotation occurs prior to heel contact and the vast majority of postural collapse of the foot occurs after forefoot contact. That is exactly what the Hammel‘s article showed, and what we observed as well.
  3. The human foot has no reference coordinate system so we used two vertically oriented cushions of 1” thick poron and placed on vertically angulated plastic sheets affixed to the simultaneously narrowing sides of a Hewlett Packard paper tray from an old printer. It is built to center paper on a tray so each side is designed to move toward the middle equally. The medial and lateral surfaces of the calcaneus are covered with indentations of usually less than 3 mm in depth, thus making the selection of individual points for reference meaningless. Therefore, we chose a mechanically induced average of medial and lateral points. Any slight error induced by the mechanical averaging of the rough sides of the calcaneus are more than made up for by the large sample size in the study. This can also be done mathematically if the surfaces were imaged in 3D. This data has already been gathered using a specially constructed structured light 3D lofting system our engineering team built and programmed. We went back to the Smithsonian and imaged all six sides of the calcaneus on the specimens. We plan on publishing those findings within the next year, time permitting.

Like all studies of bones, which is the best way to assess the relative geometric positions of large numbers of articular facets, the ligaments are not present. Since the talus has no muscular attachments, its movement, within the limitations of joint capsule and ligaments, can be predicted by the direction and magnitude of forces applied to facets whose geometry is known. We disagree with Dr. Phillips. The rotational forces generated down the leg are generated by the trunk of the body ratcheting around the stance phase leg as the swinging limb advances. The most important thing to understand here is that the head of talus is experiencing a rotational moment to externally rotate with the tibia, but the talar head has a steep incline to climb while experiencing the full body weight of the patient as he/she passes through midstance. When the anterior facet is everted during postural collapse, resupination becomes much more difficult for the patient. Preventing the foot from reaching the depths of pronation with kinematic control of the foot’s posture, makes resupination almost effortless and the subtalar joint can then act to externally rotate primarily in the transverse plane. When you put the head of the talus on a level anterior facet, this prevents sagittal plane motion between the talus and calcaneus; thus facilitating efficient propulsion. The section of your criticism where you describe the medial and lateral displacement that occurs throughout the gait cycle is the core reason that mapping the singular STJ axis placement in one posture, taken with no real frame of reference, off weight bearing is a meaningless exercise. A person can have a medially deviated STJ axis in one posture and a laterally deviated STJ axis in another posture. Thus, we are lead to the conclusion that posture the key to controlling foot function.

  1. MASS posture orthotics are used to describe any orthoses which is made according to the principles detailed in the exact sentence quoted by Dr. Phillips. The physics principles of Leaf springs apply the same for single and multilaminate springs. The difference between single axis theories (like Root and Kirby) and Postural theory (Glaser and Fleming) is that in MASS Posture Theory, the geometry of the plastic shell is taken from a dynamic cast of the foot with a calibrated foam which evenly compresses the soft tissues while passing force through the foot in as close to an ideal gait cycle the individual can attain with their current ranges of joint motion. Often more aggressive correction can be achieved after the patient has functioned around a more elevated posture for a few weeks or months, so it is wise to choose a heat adjustable material. Root did have full contact between the foot and his orthotics but at a much lower posture. Our consistent experience has been that lowering the arch about 8 mm will cause arch pain that appears to be caused by the repetitive impact of the foot as it pronates into the rigid device. Arch fill is almost universal for Rootian orthotics, although, as you point out, it did emanate from plaster modifications that Root himself made to the cast.

We asses full contact in our lab with an F-scan. It is not perfect during all phases of the gait cycle, but it is a major improvement over the hard flat tilted plates that Merton Root called orthotics. We are sorry that your MASS posture orthotics were uncomfortable, but we do remember that you began modifying them immediately without even giving them a chance to break-in. We think this single failure can be attributed to personal bias.

In conclusion, Dr. Phillips is an expert on Rootian History. He told Dr. Glaser that he and his father attended, recorded and transcribed personally every lecture that Merton Root ever delivered. What this article does is give many of the pieces of the puzzle that we call foot biomechanics. It gives the clinician a viable alternative to Root theory that chooses to address the collapse of the foot’s posture rather than a series of off weight bearing static measurements that have neither inter-rater reliability nor correlation to the kinematics of gait. It is better to find the posture that most closely mimics the beginning of the foot’s postural range of motion, with the soft tissues evenly compressed and use that geometry for a calibrated leaf spring to resist collapse of the foot’s posture throughout the gait cycle. RCCT’s like E. Higbie et al, demonstrate the measurable positive influence MASS posture orthoses can have on the gait cycle. There are other labs that use the MASS geometry but no one that I know of has copied calibration yet, although it is taught in Dr. Glaser’s lectures and on videos posted on Youtube (solesupportstv) exactly how the device is constructed, and how the math is done to recreate calibration. MASS Theory, MASS Posture, MASS Posture casting technique, or even calibration is patented or trademarked, just as Root never trademarked “Neutral Position”. The Neutral Position of rotation around the STJ axis was his gift to Podiatry. MASS Posture is ours.

Thank You,

Edward S. Glaser, D.P.M

David C. Fleming

December 2016

9 (4), 2016

Intramedullary rodding of a toe – hammertoe correction using an implantable intramedullary fusion device – a case report and review
by Christopher R. Hood JR, DPM, AACFAS, Jason R. Miller, DPM, FACFAS

The effects of CrossFit and minimalist footwear on Achilles tendon kinetics during running
by Jonathan Sinclair, and Benjamin Sant

Coronal plane talar body fracture associated with subtalar and talonavicular dislocations: A case report
by Barıs YILMAZ, MD, Baver ACAR, MD, Baran KOMUR, MD, Omer Faruk EGERCI, MD, Ozkan KOSE MD, FEBOT, Assoc. Prof.

Atraumatic acute compartment syndrome secondary to group C Streptococcus infection
by Amelia Aaronson, Malcolm Podmore, Richard Cove

Effects of high and low cut on Achilles tendon kinetics during basketball specific movements
by Jonathan Sinclair, Benjamin Sant

Use of an external vibratory device as a pain management adjunct for injections to the foot and ankle
by Joseph D. Rundell, BS, Joshua A. Sebag, BA, Carl A. Kihm, DPM, FACFAS, Robert W. Herpen DPM, Tracey C. Vlahovic DPM

Letter to the Editor

by Robert D. Phillips, DPM1

1 – Orlando Veterans Administration Medical Center

Dear Sir,

I read with interest in the March issue the article by Glaser and Fleming, “Foot Posture Biomechanics and MASS Theory.”  If this article had appeared in a non-refereed magazine, I probably would not have said much, however since The Foot and Ankle Online Journal purports to be a refereed journal, with peer review of submitted articles, I am going to have to chide the reviewers for allowing an article with such sloppy scholarliness slip by them.  The article with riddled with gross misstatements about what Dr. Merton Root taught, poor interpretation of the limited literature it presented as references, and poor thought logic and reasoning, and statements of authoritative opinion that have less research to back them up than the opinions of Root they supposedly tear down.

Let’s first of all look at some of the outright misstatements about the theories of Merton L. Root

  1. In the very first paragraph, the authors state, “He [Root] discovered that by placing the patient prone while holding the off weight bearing foot in a palpated, “neutral” position, it was observed that most heels were inverted; rearfoot varus.”  

Nowhere in the cited reference does Root make such a statement, though he does say that rearfoot varus is one of the common causes of excessive subtalar joint pronation (p.298) and also that compensation for rearfoot varus did not usually produce highly pathological conditions as the subtalar joint would still resupinate after heel off (p 313) [1].

Now, it is true that some of Root’s contemporaries have taught that most people have rearfoot varus.  This particular writer has heard many times such theory from colleagues, e.g. Dr. Chris Smith, however Root himself did not did not teach this. Phillips and Phillips (1983) found in the average patient in their series had 1.5° of subtalar varus [2]. McPoil et al. (1988) reported that 84% of young females had subtalar varus, with 41% less than 4° and 41% between 4°-8° [3]. On the other hand Åström and Arvidson (1995) reported the average person had 2° of subtalar valgus [4].  

It should be pointed out that Root never believed that the average person represented the normal foot.  A full and most scholarly discussion of Root’s concept of normal can be found in the historical treatise by Lee of the Root concepts (2001) [5].

  1. The authors go on to state, “Root recommended taking 17 measurements called the Static Biomechanical Exam [2]”.

Root did not call the examination “the Static Biomechanical Exam”.  He called the form, “Biomechanical Exam of Lower Extremities.”  The exam is broken into 7 basic areas, the metatarsus, the midfoot, the rearfoot, the ankle joint, the lower leg, the hip, and a static functional test.  The word ‘static’ could possibly be applied to three fixed measurements, i.e. the malleolar torsion, the forefoot to rearfoot relationship and the tibial angulation with the ground.  The others are ranges of motion wherein the joints have capability to function.  Therefore we could state that part of the exam is static, part is functional ranges and part is measure of function.  In addition to taking goniometric measurements, he also advocated extensive and complete muscle testing.

  1. The authors state, “Treatment was aimed at correcting what was viewed as a frontal plane deformity with frontal plane correction of the rearfoot and forefoot, called posts, designed to encourage the foot into a more neutral rotational position around the subtalar joint (STJ) axis.”

There are several errors in this one sentence.  First of all treatment was aimed at stabilizing the midtarsal joint by capturing the plantar foot shape in a nonweightbearing state, and using a “rigid” material to push the midtarsal joint toward this state.  The stable state of the midtarsal joint is based on the twisted plate theory, first advocated by Steindler (1929) [6]. This twisted plate theory of function was rejected by Schuster (1976) [7] The orthotic did not correct the forefoot or rearfoot, it merely tried to support either the medial or lateral side of the forefoot off the floor when the subtalar joint was in neutral.  This support platform is called the forefoot post. The rearfoot post was added much later to make the orthotic more stable in the shoe, not to make any corrections.

The authors try to confuse the reader with their last phrase, utilizing terminology that is redundant jargon. All researchers of subtalar joint motion papers have maintained that there is an axis for the joint to move around.  Variations in methodology have disagreed as to whether the motion is a strict axis motion [8], a moving joint axis [9] or a helical motion [10]. Whichever it is, it is unknown what a “neutral rotational position is.”  Root did state that a majority (not all) orthotics should push the subtalar joint closer to its neutral position, not because the heel was more stable, but because the midtarsal joint is more stable when the subtalar joint is in neutral position.

  1. The authors state, “Neutral position, which Root defined as “neither pronated nor supinated”, is simply a rotational position around a singular axis; the subtalar joint axis.  Pronation and supination are defined in both the open and closed chains as rotations around this singular axis.”

The authors are very imprecise in their discussion of Root theory, and in doing so they muddy the reader’s minds as to what Root stated.  Root stated that there is a neutral position of the subtalar joint.  He also stated that there were neutral positions of other foot joints, including the hip joint, the ankle joint and the first ray.  He discussed pronation around the subtalar joint during gait, as well as pronation around the oblique axis of the midtarsal joint and the long axis of the midtarsal joint.  It is important to realize that pronation of the subtalar joint in closed kinetic chain is passively accompanied by pronation around the oblique axis of the midtarsal joint and supination around the long axis of the midtarsal joint.  These three motions are seen as a single motion, which Nester described as motion around a single axis that moves (1997) [11].

  1. The authors make the following statements regarding what Root taught about how many axes there are in the foot: “The extreme of single axis theory is to imagine that the foot only has one axis and consider the foot as just two rigid bodies teetering around this singular axis.  This model concerns itself with the distribution of kinetic forces and their perpendicular distance to this one axis.  This describes the Subtalar Axis Location and Rotational Equilibrium (SALRE) theory of Kevin Kirby, DPM.” …  “The basic difference between single axis models, such as the STJ Neutral Model, and a postural model is that single axis models, by definition, ignore the rest of the foot” …. “The basic difference between single axis models, such as the STJ Neutral Model, and a postural model is that single axis models, by definition, ignore the rest of the foot.  You can find STJ neutral in a broad range of foot postures both in the open and closed kinetic chain.”

These statements are a gross misrepresentation of both Root and Kirby.  As noted above, Root never described motion of the foot as occurring around a single axis.  Root described motion of the foot as occurring around multiple joint axis, including motion around the subtalar joint, the midtarsal joint, the ankle joint, the first and fifth ray joints and motion around the metatarsophalangeal joints. Kirby likewise never said that the foot rotates around one axis, though he most often writes and talks about the subtalar joint axis, so that the casual reader or listener may believe that he believes there is only one axis of motion for the entire foot.

  1. The authors somehow believe they have discovered something unique with these statements.  “Posture is simply stepping back and looking at the foot as a whole and observing the way elevation of the longitudinal arches causes bones to nest into each other in a more closed pack position.  Paul Jones attributes this to a generalized spiral twisting of the forefoot on the rearfoot, The Wring Theory [11].  Sarrafian described the frontal plane forefoot to rearfoot relationship as a twisted plate. All of these models are posture based [13].  Posture is the All Axis Model.”

Root was very much a twisted plate theorist, though he may not have ever used those exact words.  Forefoot varus had been described in the literature before Root, however this writer has not found any previous author who described forefoot valgus [12].  Root was the one who proposed that a pathology of the forefoot to the rearfoot could be only be diagnosed if the entire range of midtarsal joint motion had been utilized in the pronation direction.  Posture of the foot in static stance and also function of the foot was partially dictated by these forefoot to rearfoot relationships and available motions.

  1. The authors then make the following statement: “The small amount of STJ rotation is where Merton Root and Kevin Kirby concentrated their attention [4].  According to Root’s own measurements the total range of STJ rotation in ideal gait is only six degrees (+2 to -4).”

First of all, Root never took measurements of the foot motion in ideal gait, though he did measure range of motion available for the subtalar joint to move within and also the static subtalar joint position in stance.  As to gait, Root looked to the best literature of his time for information about the range of motion of the subtalar joint during gait [13,14]. Since then, multiple authors have shown that Root’s proposal of the range of subtalar joint motion that the foot utilizes during gait is basically correct [15-19]. All authors, including Root, have agreed that subtalar joint motion when the heel is on the ground is small, but that once the heel comes off the ground, during propulsion, it is significantly more.

  1. The authors make the following statements: “Traditional orthotics based on the single axis models tend to be rather low in posture.  The cast is taken in a partially pronated position and then the arch is further lowered to varying degrees to make the orthotic tolerable.   Filling in, or lowering the arch of the orthotic, is often called ‘cast correction’ even though it divorces the geometry of the foot from the geometry of the orthoses and allows for greater postural collapse before the orthotic is contacted by the arch.”

What do the authors mean that the cast is taken in a partially pronated position?  The Root technique takes a typical cast with the subtalar joint in neutral position and the midtarsal joint in its fully pronated position.  This was the truly innovative idea that Root proposed, that the orthotic should have a supinatory effect on the subtalar joint and a pronatory effect on the midtarsal joint [20].  I haven’t read of anybody advocating taking a partially pronated cast.  It is true that many orthotic laboratories excessively lower the arches of the orthotic casts they receive.  This is not “cast correction” as the authors maintain.  

I recommend to the authors the following text by Dr. Root:  “Plaster modifications for the standard functional orthosis consist of the balance platforms beneath the first and fifth metatarsal heads, a filler between these platforms, a lateral expansion, and a medial arch filler….” “The lateral expansion of plaster is designed to accommodate the slight bulging of soft tissue all along the lateral side of the foot and around the lateral and posterior aspect of the heel. This prevents the orthosis from pinching this soft tissue, which occurs in a significant percentage of feet if a lateral expansion is not used”…. “The plaster medial arch filler is designed to flare the medial edge of the orthosis away from the medial arch of the foot to prevent the edge of the orthosis from cutting into the foot. It initially was used only on feet with a fairly large angle of forefoot adductus because such feet have a sharp angle in the medial arch in the area of the midtarsal and tarso-metatrasal joint. It was not possible to train technicians or new practitioners to recognize when this medial arch filler would be necessary. As a result, a filler was standardized that could be used on any foot without interfering with function of the orthosis.  The medial arch filler should extend form about mid-shaft of the first metatarsal and no farther posteriorly than the midtarsal joint. The filler should extend laterally in the arch of the foot to a line slightly lateral to where the medial edge of the finished orthosis will sit when placed on the cast” [21].

We can see from Root’s own description, the medial expansion was not intended to lower the medial arch but rather to flare only the very medial aspect of the medial edge away from the soft tissue. Many laboratories use the medial expansion as an accommodation for practitioners who send a tremendous number of casts taken with the long axis of the midtarsal joint supinated, or the first ray dorsiflexed or the lateral column plantarflexed.  This is a business decision by these companies to accept casts that are of poor quality and then produce a device that does not hurt the patient.  It does reflect on the poor practices of a great many clinicians in this country.

This writer has also made some observations about the advantages of the true Root orthotic flaring the orthotic away from the most medial edge of the arch of the foot.  One of these is that the orthotic must allow normal pronation to occur during the contact period of gait.  Second is that the lateral column is more flexible than the medial column.  Therefore when the orthotic is made of uniform thickness, the lateral column of the orthotic flexes more than the medial column, which supinates the long axis of the midtarsal joint and makes the orthotic more uncomfortable on the medial side.  If the clinician makes the lateral column thicker than the medial column, then equal flexes of both columns can be achieved and the orthotic lab does not have to artificially lower the medial arch.  Again it should be emphasized that the Root orthotic is not an arch support — it is a dynamic torsional device, intended to provide an inversion force on the rearfoot, with support under the sustentaculum tali, and to evert the forefoot against the rearfoot.

Let’s look at some of the poor representation of the literature used to support the authors’ contentions that the theories of Root should be discarded.

  1. The authors state the following: “Root et al, called Royal Whitman’s observation the phenomena of midtarsal locking and unlocking and attributed it to Elftman’s theory, that the talonavicular and calcaneocuboid axis deviated as the foot supinated [9].  Thus, this decreased the range of motion and parallelism of the axes, results in increased range of motion.”

The authors correctly state that in 1971, at the publication of their first book, Root et al did believe in the “locking” position mechanism proposed by Elftman, however by the time of their 1977 seminal publication, Root et al. had discarded the theory of Elftman as why the midtarsal joint had a smaller range of motion when the subtalar joint was in a supinated position than when it was in a pronated position.  The authors would find a detailed account of first the acceptance and then the rejection of the Manter theory by Root in the exhaustive work by Lee on the history of Root’s ideas (2001) [5].

  1. The authors make the following argument: “The STJ axis exits the foot at the same point; the momentum down the leg similarly point; the momentum down the leg similarly passes its force vector down the center of the dome of the talus thereby intersecting the STJ axis..  The ground reactive force enters the foot ideally on the plantar posterior lateral aspect of the heel asses its force vector down the center of the dome of the talus thereby intersecting the STJ axis.  The STJ axis is placed in an orientation that passes through the major forces entering the foot at heel contact, other than the force of friction which is horizontal and causes the forward roll of the calcaneus.”

The authors seem to be oblivious to the paper by Phillips and Lidtke (1992) that shows that the subtalar joint axis does not exit the foot at the posterior-lateral-inferior edge of the calcaneal fat pad, but instead intersects the posterior calcaneus between 4-5 cm above the inferior edge, and it intersects the ground approximately 5 cm posterior to the heel.  This means that the actual point of contact at the initiation of the gait cycle is actually lateral to the subtalar joint axis.  What the authors also fail to realize is that there is a significant shear force, directed laterally during contact, created by the internal rotation of the leg.  While this shear force may be only about 10% of the vertical force, it has between 5-10 times the lever arm with the subtalar joint axis, so that it has an angle that is more perpendicular to the subtalar joint axis than the vertical ground force.  This means that the horizontal, laterally directed shear force produces at least 50% of the total pronation torque around the subtalar joint axis.  The authors try to confuse the reader with their description of what the shear forces do.  The posterior shear force rolls the calcaneus forward at the ankle joint, not the subtalar joint.  Readers will find a detailed description of what how the vertical, the medial-lateral and the anterior-posterior ground forces affect each joint of the lower extremity, from the hip to the toe through the entire gait cycle, in the chapter on biomechanics by this writer in the text, Principles and Practices of Podiatric Medicine (2007) [23].

  1. The authors make the following statement: “Tom McPoil’s Tissue Stress Theory states that when microtrauma occurs faster than a person’s ability to heal, they experience a symptom.  During the last few degrees of postural collapse tissue stresses are highest.  Microtrauma occurring in this zone of foot posture causes symptoms.”

Those who claim to be “Tissue-Stress Theory” advocates, fail to recognize that Root was also a tissue stress advocate. Just a couple of quotes from his major work demonstrate this.  For example on page 229 we find, “The everted calcaneal position, which results from pronation that compensates a forefoot varus deformity, causes … a significant everting rotary moment that causes further pronation of the subtalar joint … The inherent arch structure of the foot begins to collapse, and ligamentous stretching and strain ensues.  The entire rearfoot becomes unstable.”   Later on page 326 we find, “The weightbearing forces move the joint either beyond its normal range of motion, or in a direction other than its normal plane of motion.  In either event, the ligaments are immediately placed under tension.  Since ligaments are elastic, they continue to elongate as long as the subluxing force is unresisted, and the articular surfaces separate slightly or may even dislocate with time.”

This writer often personally heard Root say that one only had block the last 1°-2° of subtalar joint pronation to alleviate a patient’s symptoms.  Certainly a great many papers have shown that a great many “Root-type” orthotics only prevent about 2°-3° of calcaneal eversion [24-27]. Therefore it is evident that the majority of the studies on the “Root” orthotics are documenting a marked decrease in symptoms with only small changes in kinematics, which supports the idea that symptoms are caused by plastic deformation of ligaments.  McPoil should not be considered to have introduced a new theory of biomechanics, but instead to give added definition and clarity to the basic Root principles.

  1. The authors contend that different types of activities require different orthotics with the following argument: “Momentum (mass times velocity) is the third factor that affects the magnitude of the downward force of the body.  Running over a force plate produces more impact force than walking. Therefore, we must consider a range of forces to resist called, ADL or activities of daily living, and calibrate the orthotic to deliver an equal and opposite range.  Athletes may have a different range of forces, these can be referred to as training or competing ranges, which are much higher.  A power lifter, for example, may want an orthotic calibrated to resist his entire weight plus the weight he is deadlifting or squatting.  That same athlete will need a different pair of orthotics for his ADL.”

This paragraph assumes that all ADLs require the same amount of pronation or supination.  If this were true, then the authors’ argument would be correct, however we know that when running, the foot has to pronate more [28].  Therefore to make an orthotic thicker for running, would limit the runner to less than the desired amount of pronation.  The Root orthotic, on the other hand, says that with increasing vertical braking force of the ground, such as what the runner encounters with every foot strike, the orthotic will allow greater amounts of pronation. Just as the Modulus of Elasticity is the same for the foot when it is walking as when it is running (assuming a nonviscoelastic model), so the same orthotic can often be used for many different activities, as it will flex more when running, thus allowing for more pronation, than when walking.

  1. The following statement about practitioner testing the patient is made by the authors: “Foot flexibility can be measured in different ways.  One way to grade foot flexibility is to rotate the forefoot around the fifth metatarsal.  This is called the Gib Test or forefoot flexibility Forefoot Flexibility Test.  The foot can be graded from one to five [20].”

The reference is to the primary author’s own article in a non-refereed magazine article.  Inspection of this article shows nowhere in it is there anything about the Gib Test or the Forefoot Flexibility Test.  A search of the NHI library likewise turns up no article that discusses the Gib Test.  The only place that a practitioner can learn anything about this test is a Youtube video [29].

  1. In regards to some limited research that has been done with the MASS orthotic, the authors state the following:  “Higby measured the force distribution on the metatarsal heads at toe off [23]. What are these forces? Initially, MASS posture orthotics transferred 44% more force to the first metatarsal head at toe off than neutral position orthotics with posts. At six weeks this difference grew to 61% (p=.006) [24]. This means that when the arch is raised, the first ray not only comes down and lateral, but additionally increases its purchase.”

First the editors should have noticed that reference 23 and reference 24 are the same, to a paper by Hodgson, Tis, Cobb, McCarthy and Higbie (not Higby) [30].  So let’s look at the paper quoted by Hodgson.  Glaser and Fleming have totally misrepresented the paper.  The paper looked at two groups, both with greater than 7° forefoot varus.  One was assigned to be treated with a 3/16” polypropylene orthotic manufactured by PAL Labs of Pekin, Ill., and the other by Sole Orthotic Lab.  The “Root” orthotic in this study differed from classic Root techniques in that cast was taken using a prone non-weightbearing casting technique, and the material was more flexible than what Root advocated.

When one looks at the two groups, we see some glaring differences before wearing orthotics.  The “Root” group showed an initial condition in which the first metatarsal head was bearing 71 KPa less pressure than the central metatarsal head area, and the SOLE group had an initial difference of the first metatarsal head having 41 KPa less pressure than the central metatarsal head area.  This is a very significant difference showing that the Root group had significantly more hypermobility of the first ray than the SOLE group.  This is an interesting statistical aberration, where random assignment to two groups does not always produce two groups of equality.

When we look at the end results (6 weeks of wearing the orthotics), the hypermobility of the first ray had not changed with either group.  The first group still shows the first metatarsal head area to be averaging 73 KPa less than the central metatarsal head area, and the second group still shows the first metatarsal head averaging 40 KPa less than the central metatarsal head area.  Therefore the claims by the authors that the SOLE orthotic increased the pressure under the first metatarsal more than the Root orthotic is not an accurate interpretation of the data.

There is an assumption here that the more force one produces under the first metatarsal head, the better the foot is functioning. Actually the Hodgson study is measuring pressure, not force, and in this writer’s eyes, the average pressure under the metatarsal heads over the entire gait cycle should be equal for all five.

Finally the following examples are ways that authors make outlandish assumptions, demonstrate poor reasoning, and write what can be best called “mechano-babble”.

  1. The authors make the following statement: “I propose that the locking mechanism of the midfoot is multifaceted.  When the talar head is directly on top to the anterior facet, sagittal plane motion between the talus and calcaneus is blocked.  Thus, when the gastroc-soleus complex fires, rotation occurs at the ankle joint.”

Not quite sure why the personal pronoun is utilized at the beginning of the article.  Who is the “I”, Dr. Glaser or Dr. Fleming?  This is just one of many editorial errors in the article.  Nevertheless, the assumption that the anterior facet blocks sagittal plane motion between the talus and the calcaneus is faulty reasoning.  First of all, a great many people show the anterior and middle and anterior facet to be one continuous surface [31-33]. The authors fail to mention how the middle facet plays into the equation in blocking subtalar joint motion.  It is well recognized that the middle facet is larger than the anterior facet, so why doesn’t the middle facet block sagittal plane motion, especially since it is further from the subtalar joint axis than the anterior facet?  And what about people with no anterior facet, is there anything blocking subtalar joint motion [34]?

Second of all, the subtalar joint moves around an axis.  It is true that that the facet morphology determines the direction of the subtalar joint axis.  It is important to remember that when we talk about subtalar joint motion being tri-planar, we are not talking about three different motions, we are only saying that angular motion can be measured in three different planes.  Therefore, the more horizontal the facets are with the ground, the greater will be the angular displacement measured in the transverse plane rather than in the sagittal or frontal plane.  In other words, the subtalar joint axis will be more vertical, and therefore the lower will be the torque around subtalar joint axis exerted by vertical ground forces, and the greater will be the torque exerted by shear ground forces.  Since there are strong transverse plane rotational forces occurring in the lower leg during gait, no one can say that a subtalar joint axis that is more vertical will demonstrate less total motion, though a person that has only the capability to measure the frontal plane component of motion may erroneously conclude that less motion may be occurring [35].

Finally, the authors try to confuse the situation with a statement about rotation around the ankle joint occurring when the gastroc-soleus fires.  It is important to remember that when the gastrocnemius-soleus fires, it primarily produces a plantarflexion torque of the calcaneus against the tibia.  Since the ankle joint axis is almost perpendicular to the Achilles tendon, the major torque is around the ankle joint.  The axis of the subtalar joint has a lower angle with the Achilles and a shorter lever arm, therefore the supination torque is lower around the subtalar joint axis than the ankle. The greater the pitch of the subtalar joint axis with the transverse plane, the less will be the torque exerted by the Achilles on the subtalar joint.  Now in closed kinetic chain, when the firing of the gastrocnemius produces a first class lever effect, creating ground reaction force against the metatarsal heads.  This ground reaction force creates a strong dorsiflexion torque around the midtarsal joint.  This dorsiflexion torque is resisted by the ligaments of the plantar foot.  A simple geometrical construct shows that the lower the arch, the greater will be the tension on the plantar ligaments.

  1. The authors make the following statements: “As the foot goes into further elevation of its posture, there is a zone where, according to Hammel, there is no significant rotation around the STJ axis in any plane [17]. Foot orthoses that attempt to elevate posture into this zone often cause medial longitudinal arch pain as the foot repeatedly drops down to impact the orthotic.  Hammel showed that from 25% to 90% of the stance phase of gait, no rotation in any plane occurs between the talus and the calcaneus.”  

First of the use of the paper from Hammel to back up this statement is bogus.  An examination of the paper shows that cadaver feet were utilized to try to simulate gait and the simulator had no transverse plane simulation of the leg.  Without the ability to simulate transverse plane motion of the lower leg, of course they will not be able to pick up the motion of the subtalar joint between 25%-90% of the stance phase of gait. There are many other papers Glaser and Fleming could have picked to discuss the subtalar joint motion that have in vivo multisegment data on all three body planes, including Carson (2001), Hunt (2001), Simon (2006), Stebbins (2006), Leardini (2007), Nester (2007), Pohl (2007), Nester (2014) [36-43].  While all of these authors used slightly different marking systems of the foot when walking, none of them grossly contradicted the original gait cycle motions of the ankle, subtalar or midtarsal joints described by Root and all of these papers, plus many more, contradict the statement of Hammel that Glaser and Fleming rely on.

The statement that subtalar rotation and postural collapse are independent events occurring at different times in the gait cycle is not really a valid statement.  Root stated that subtalar joint pronation occurs before the forefoot hits the ground.  The moment the lateral side of the forefoot touches the ground, the pronation of the midfoot in the sagittal plane starts to occur.  The problem is that the force is transferred gradually to the forefoot from the heel.  Thus the dorsiflexion moment across the midfoot increases throughout the midstance period of gait.  It is the pronation of the subtalar joint that increases the midtarsal joint range of motion in the pronation direction.  Limited data exists in this regard as to the exact mechanism by which the STJ position changes the mobility of the MTJ, and many theories have been proposed [44,45].

At the end of this section in the paper, the readers are still scratching their heads as to what the writers mean by the “Dysfunctional Zone”.  It is even more nebulous and ill-defined than Root’s “neutral position.”

  1. The authors make the following statement: “As foot posture elevates beyond the Dysfunctional Zone the anterior facet of the STJ approaches level in the transverse plane.  This allows subtalar rotation to occur.  This is where the talar head slides posterior and rotates its six degrees around the STJ axis.  The closer the anterior facet is to level, the easier the subtalar rotation occurs and the rearfoot locks in the sagittal plane facilitating efficient propulsion.”

It should be noted that the authors are relying on their own study published in this same edition of the journal on his measurements of facet deviations from each of the planes.  Unfortunately, this paper appears at first to have some real data, however a close read of the paper shows that it is mathematical gibberish.  The quoted article fails to define the reference coordinate system and what directions are positive and negative.  Also the deviation between two planes is determined by the angle between the normals  of the two planes.  If one says that the angle between a facet and the transverse plane is 10°, it could mean that the facet is tilted forward or it could mean that the facet is tilted medially or laterally.  What the author should have done is set up his reference coordinate system and then expressed the normals to the planes of the facets in either spherical or cylindrical terms.  It is noted that most podiatric texts express axes in cylindrical terms.  So with no definitions in the quoted article, the data is useless.

To define the ease of movement on the orientation of one portion of the total joint surfaces that comprise it, and on no ligamentous restraints is totally to ignore mechanics.  As Phillips and Lidtke pointed out, the subtalar joint can be clinically modeled to move around a single axis that is fixed to the talus.  As the talus dorsiflexes in the ankle joint, the subtalar joint becomes more vertical, therefore vertical ground forces produce less torque around the subtalar joint axis and horizontal forces produce more torque.  Therefore transverse plane leg rotations produce stronger subtalar joint torques, and these rotational forces are being generated by the movement of the swing leg.  Also as the talus abducts, the subtalar joint axis moves laterally, producing longer lever arms for the vertical forces medial to the subtalar joint axis and shorter lever arms for the vertical forces under the lateral foot.  So the ease of subtalar joint supination with the foot in a more supinated position can be fully explained without any need for the horizontal position of the anterior facet.

  1. The authors make the following claim: “A MASS Posture composite leaf spring applies an even distribution of force per unit of area by remaining in full contact with the foot throughout the gait cycle.  The foot never has to drop down to hit the orthotic because it is already touching it, which minimizes impact and thus tissue stresses.   It is the combination of full contact  (redistribution of force per unit area) eliminating hot spots and the lack of repetitive impact that allow such a spring to apply a rather large corrective force while remaining comfortable to most patients.  Once you have the correct geometry of the spring, it is time to adjust the spring constant.”

The authors have never demonstrated how their orthotic is constructed like a leaf spring, or why his orthotic is a leaf spring and the Root orthotic is not.  Leaf springs are laminar with the thickest part of the spring in the middle, where the highest load area is.  The MASS theory orthotic is a single lamina and is ground thinner in the middle.

All orthotics remain in full contact with the foot throughout the gait cycle as the foot will mold itself to fit the orthotic shape, which is also a basic tenet of Root orthotic therapy.  A Root orthotic starts pushing against the bottom of the foot when the foot makes contact with it when the STJ is in neutral and the MTJ is pronated.  The more the foot tries to deform from STJ neutral and MTJ pronated, the harder the orthotic pushes against the bottom of the foot.  Blake and Kirby have both proposed modifications of the Root orthotic that initiates the orthotic producing a supinatory force against the heel before the subtalar joint tries to pronate beyond neutral [46-49].

How do the authors know there are no hot spots on the MASS orthotic?  You have to have a pedobarograph to measure that, and there is no literature that has measured the force that the MASS orthotic puts against the bottom of the foot.  This writer’s personal experience with the MASS orthotic is that it produces an extreme hot spot under the medial arch.  If the orthotic is casted with the forefoot maximally plantarflexed against the rearfoot, then there will be a very high hot spot under the arch, unless the orthotic is flexible enough to lower under normal weightbearing to that point where tension develops in the plantar ligaments.  Since there is no quantitative measures taken by the clinician before prescribing a MASS theory orthotic, neither goniometric nor pedobarographic nor kinematic measurements, only a qualitative judgement of the frontal plane mobility of the forefoot to the rearfoot, there is no way that the laboratory has any information about how much the forefoot plantarflexing mobility the patient has.

In conclusion, MASS theory has little to any support for its validity in the literature.  There is only very limited literature on the use of the MASS orthotic.  Currently there is only one source of MASS orthotics, and the authors of the reviewed article have a definite conflict of interest in the proposals offered.  This writer will admit that there are definite problems in the classic “Root” approach that is commonly taught, and many authors since the original Root writings have definitely made valuable additions, clarifications and corrections to the Root approach.  However, this writer, through study of the literature and clinical practice maintains that the literature better supports Root concepts, and therefore MASS theory cannot be accepted as a replacement for currently accepted practices and theories.

Thank you,

Robert D. Phillips, D.P.M.

Orlando Veterans Administration Medical Center

Disclaimer:  the opinions in this paper are those of the writer alone, and do not represent the opinions of the U.S. Department of Veterans Affairs nor any other branch of the U.S. government.


  1. Root, M. L., Orien, W. P., & Weed, J. H. (1977).Normal and Abnormal Function of the Foot (Vol. 2). Los Angeles: Clinical Biomechanics Corporation
  2. Phillips, R. D., and R. L. Phillips. “Quantitative Analysis of the Locking Position of the Midtarsal Joint.” Journal of the American Podiatric Medical Association 73, no. 10 (1983): 518-522.
  3. McPoil, Thomas G., Harry G. Knecht, and Dale Schuit. “A Survey of Foot Types in Normal Females between the Ages of 18 and 30 Years*.” Journal of Orthopaedic & Sports Physical Therapy 9, no. 12 (1988): 406-409.
  4. Åström, Mats, and Tina Arvidson. “Alignment and Joint Motion in the Normal Foot.” Journal of Orthopaedic & Sports Physical Therapy 22, no. 5 (1995): 216-222.
  5. Lee, William Eric. “Podiatric biomechanics. An Historical Appraisal and Discussion of the Root Model As A Clinical System of Approach in the Present Context of Theoretical Uncertainty.” Clinics in Podiatric Medicine and Surgery 18, no. 4 (2001): 555-684.
  6. Steindler, Arthur. “The Supinatory, Compensatory Torsion of the Fore-Foot in Pes Valgus.” Journal of Bone and Joint Surgery Am 11, no. 2 (1929): 272-276.
  7. Schuster, R. O. “Neutral plantar impression cast: method and rationale.” Journal of the American Podiatry Association 66, no. 6 (1976): 422-426.
  8. Hicks, J. H. “The mechanics of the foot: I. The joints.” Journal of Anatomy 87, no. Pt 4 (1953): 345.
  9. Lundberg, A., and O. K. Svensson. “The axes of rotation of the talocalcaneal and talonavicular joints.” The Foot 3, no. 2 (1993): 65-70.
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September 2016

9 (3), 2016

Persistent distal sciatic neuropathy following popliteal nerve block in foot and ankle surgery
by Spencer J. Monaco DPM, Alissa Toth DPM, Dane K. Wukich MD

Posterior dislocation of the subtalar joint: A case report
by Vijay Kumar Kulambi, MBBS, MS (ORTHO), Deepak. A, MBBS, (D. ORTHO)

Application of the distally pedicled peroneus brevis: Technique, case study, and pearls
by Chad Seidenstricker DPM, Megan L. Wilder DPM, Byron L. Hutchinson DPM, FACFAS

Fibromatosis of the soleus muscle presenting as pes equinus: A case report
by Hirofumi Bekki MD, Jun-ichi Fukushi MD PhD, Hideki Mizu-uchi MD PhD, Makoto Endo MD PhD, Yoshinao Oda MD PhD, Yukihide Iwamoto MD PhD

Differences in the degree of stretching applied to Achilles tendon fibers when the calcaneus is pronated or supinated
by Mutsuaki Edama, Masayoshi Kubo, Hideaki Onishi, Tomoya Takabayashi, Takuma Inai, Hiroshi Watanabe, Satoshi Nashimoto, Ikuo Kageyama

The application of generic CAD/CAM systems for the design and manufacture of foot orthoses
by Alfred Gatt PhD, Cynthia Formosa PhD, Nachiappan Chockalingam PhD

Prematurely symptomatic tarsal coalition with peroneal spasm in a 2-year-old
by Robert L. van Brederode, DPM, FACFAS

Neglected Achilles tendon rupture and repair with cadaver allograft, extracellular matrix, and platelet enriched plasma
by Al Kline, DPM

Prospective study of plantar fascia thickness correlated to efficacy of conservative treatment for plantar fasciitis using ultrasonography
by Gerald Kuwada, DPM, NMD

Letter to the Editor
by Robert D. Phillips, DPM

Posterior dislocation of the subtalar joint: A case report

by Vijay Kumar Kulambi, MBBS, MS (ORTHO)1, Deepak. A, MBBS, (D. ORTHO)2*pdflrg

The Foot and Ankle Online Journal 9 (3): 2

Dislocation of the talocalcaneonavicular or subtalar joint is a rare occurrence. Posterior subtalar dislocations are even rarer among subtalar dislocations. The injury is characterized by a simultaneous dislocation of talocalcaneal and talonavicular joints while tibiotalar and calcaneocuboid articulations remain intact. Although many of these dislocations result from a high-energy injury, such as a fall from a height or RTA, a significant number of these injuries occur as a result of athletic injuries. Closed reduction and immobilization remains the treatment of choice. Early anatomical reduction is the key to preventing long term complications such as midtarsal joint arthritis and faulty foot mechanics.  However, if closed reduction is unsuccessful in some patients, open reduction is required. A variety of bone and soft tissue structures may become entrapped, resulting in obstruction of closed reduction. This is a unique case report which presents an unsuccessful closed reduction of a closed posterior subtalar dislocation that required open reduction.

Key words: subtalar joint dislocation, foot trauma, STJ, joint dislocation

ISSN 1941-6806
doi: 10.3827/faoj.2016.0903.0002

1 – Professor of Department of Orthopaedics. JJM Medical College, Davangere, Karnataka State, India 577004.
2 – Postgraduate student, Dept. of Orthopaedics, J.J.M. Medical College, Davangere, Karnataka State, India 577004.
* – Corresponding author: /

Subtalar joint (STJ) dislocation is a rare injury of the foot and ankle with most reported cases occurring after major trauma. The rarity of this injury can be attributed to the presence of strong ligament connecting the talus and the calcaneus, the strong biomechanical properties of the ankle and the tight joint capsule. When a dislocation occurs to this joint, it is considered a serious injury due to the instability that can occur across Chopart’s joint [1].

Main and Jowett described this dislocation type injury occurring at the midtarsal joints with a classification system to help the physician decide the best course of treatment (Table 1) [2].

The dislocation results in substantial distortion of the foot shape. Fractures of the fifth metatarsal, the talus, anterior process of calcaneus and the malleoli are often a result of with subtalar dislocations [3]. Subtalar dislocations without associated fracture are rare because of the inherent instability of these types of injuries (the talus has two articular surfaces which contribute in the formation of talonavicular and talocalcaneal joints) [4].

It has also been demonstrated that injury in this area can easily dislocate the subtalar joint. In most of the cases the calcaneus and the rest foot is dislocated medially. Dislocation can be reduced spontaneously [5].

The purpose of this study is to report a rare case of a posterior subtalar dislocation with associated fractures in which closed reduction failed, and ultimately open reduction and internal fixation was done. We also describe the mechanical patterns resulting in subtalar dislocation, s-pitfalls that arise during closed reduction, choosing the right patient for open reduction.

Case Report

A 48 years old male presented with a history of one day old injury to right ankle following an accidental fall by slipping on a slope, with the right foot being forced mainly into hyperplantar flexion and eversion. He presented with complaints of pain, swelling, deformity just distal to the ankle and proximal foot, and was unable to bear weight on right foot.

Table 1 Main and Jowett classification for midtarsal joint injuries [2].

Clinical examination showed the foot being fixed in plantar flexion, mild eversion with diffuse swelling and tenderness in midfoot and proximal 3rd shaft of right fibula region without any type of external wound. A prominent rounded bony prominence was palpated at the talonavicular articulation, suggestive of talonavicular dislocation with palpable talar head. Skin over the dorsum was stretched and edematous. All movement (passive and active) of the right ankle was painful and restricted completely. There was no distal neurovascular deficit. The plain radiographs of right ankle and right leg in AP and lateral views showed posterior talonavicular dislocation with a very mild lateral displacement in the right foot with fracture of anterior process of the right calcaneum and plain radiographs of leg showed fracture of proximal 1/3rd shaft of right fibula (Figures 1 and 2). Initial closed reduction under spinal anaesthesia failed and thus resulting in open reduction with a dorsolateral approach. The talus was explored through a dorsolateral incision and the tendon of tibialis anterior was found to be interposed between the talus and calcaneus. The head of the talus was impacted onto the navicular bone, hindering the attempt for closed reduction.  Tibialis anterior tendon was retracted and talar head had to be levered back into anatomical position after opening the talonavicular joint capsule (Figure 3). The reduction was confirmed under C – arm (Figure 4) and then a thick Kirschner wire was inserted from the calcaneus into the talus to hold the reduction (Figure 5). A below knee splint was applied after placing a sterile dressing at the operative site.

Figure 1 Subtalar dislocation, fibula fracture.

Figure 2 Preoperative x- rays of the patient injured foot.


Figure 3 Intraoperative pictures from left to right;  i) tibialis anterior tendon interposing between the talar head; ii) tendon retracted and joint capsule opened exposing the talar head; iii) talar being lever back into anatomical position; iv) post reduction of subtalar joint; v) K – wire fixation post reduction of subtalar joint.


Figure 4 Intraoperative images showing talonavicular joint i) pre reduction, ii) post reduction.


Figure 5 Intraoperative images showing stabilisation of the talonavicular joint using K-wires.

Subtalar joint dislocations were first described in 1811 and have also be referred to as peritalar or subastragalar [6,7]. A more accurate term for subtalar joint dislocations would be talocalcaneal navicular (TCN) dislocations.

The most widely used classification has been described by Broca in 1852 [5], who distinguished 3 types of subtalar dislocation (Table 2): (1) the medial dislocation; (2) the lateral; and (3) the posterior dislocation. Direction of the rest foot in relation to the talus was the determinant element to classify dislocation as medial, lateral or posterior [5]. Subtalar dislocations are rare accounting for approximately 1% of all dislocations; 85% are medial dislocations with the other 15% accounting for lateral and the very rare anterior and posterior dislocations [9].
The incidence of posterior dislocation which was first described by Luxembourg in 1907 and it ranges from 0.8% to 2.5% of all TCN dislocations in different studies [3,4]. Posterior dislocation occurs when forces applied on the dorsum of the foot result in forceful extreme plantar flexion of the forefoot. It is hypothesized that pure hyperplantar flexion could lead to a progressive subtalar ligament weakening that may result in a complete ligament rupture if the plantar flexion force is prolonged [3]. This excessive hyperplantar flexion is normally the result of either a fall from a height or direct blunt force and trauma.

Direction of Dislocation Frequency of Dislocation
Medial 65-80%
Lateral 15-35%
Posterior 0.8-2.5%
Anterior 1%

Table 2 Broca and Malgaigne’s classification of talocalcaneal navicular joint dislocation with frequency [16].

This could be observed in the presence of good bone quality and if the force is applied distally at the navicular bone. The interosseous ligament and medial and lateral ligaments of the ankle joint are torn [9]. Generally there is no rotational component to posterior displacements of the TCN joint. The instances of posterior dislocations with rotational components were open injuries [10].

The diagnosis of posterior TCN dislocation can be confirmed with lateral and anteroposterior radiographs (Figure 3). On lateral radiographs, the head of the talus is atop the navicular, and the posterior portion of the talus will be in contact with the posterior subtalar facet of the calcaneus [11]. According to Inokuchi et al, the frontal view should show no significant medial-lateral displacement or rotation of the foot [3].

Immediate reduction under general or spinal anesthesia is recommended to avoid soft tissue complications and reduce the chances of avascular necrosis of the talus. Posterior dislocations are also very unstable due to the fact that the talus is balancing on two points, the navicular and the facets of the calcaneus, respectively. With posterior TCN dislocation, reduction can be achieved with no fixation by manual traction [9]. A radiograph should be performed to ensure the reduction of the dislocation and to exclude any iatrogenic fracture.

Associated fractures as cited in the literature include, talar neck and body fractures, anterior process of the calcaneus, posterior process of the talus, posterior malleolus chip fractures of the navicular, cuboid fractures, and associated osteochondral fractures [3,4,10,12]. A recent case report by Budd et al, showed that a posterior displacement was irreducible due to an anterior process fragment [12].

In general posterior dislocations do not require internal or external fixation. Fixation of associated fractures is required depending on the type of fracture, displacement, and timing of the injury. In general posterior dislocations do not require internal or external fixation. Fixation of associated fractures is required depending on the type of fracture, displacement, and timing of the injury. Good functional outcomes for closed posterior TCN dislocation have been uniformly reported in the literature [3]. Post-reduction immobilization in a non-weight bearing cast is required for TCN dislocation. In general we follow the protocol set forth by Jungbluth et al in 2010, consisting of six weeks in a short-leg cast with aggressive rehabilitation and full weight bearing thereafter [12]. Radiographs at 6-8 weeks are a usual protocol to ensure no vascular necrosis of the talus. This can also be done with the use of CT and MRI.

Most commonly, subtalar dislocation is an injury resulting from high energy trauma and, more frequently, it involves active young men. Between 10% and 40% of subtalar dislocations are open [7]. Open injuries tend to occur more commonly with the lateral subtalar dislocation pattern and probably as the result of a more violent injury. Long term follow – up demonstrated very poor results with open subtalar dislocation [7].

The duration of immobilization remains controversial. Lasanianos et al [13] suggested that for uncomplicated medial subtalar dislocations, if passive and active range of motion exercises and partial weight bearing are started earlier, the outcomes regarding functionality are better when compared to those of longer immobilization periods [14].
In our case presentation, the patient had sustained a high-energy trauma leading to a posterior subtalar dislocation. Following the initial failed closed reduction attempt under spinal anaesthesia and hence open reduction was required. We identified the tibialis anterior tendon and the impaction of the talar head on the navicular bone obstructing the possible closed reduction. This case report shows successful open reduction of a posterior subtalar dislocation with Kirschner wire fixation.


  1. Powell E, LaBella M. Swivel-type Dislocation of the Talonavicular Joint: A case report. The Foot and Ankle Online Journal 2011:4(6):3
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  3. Inokuchi S, Hashimoto T, Usami N. Posterior subtalar dislocation. J Trauma 1997; 42: 310-313
  4. Krishnan KM, Sinha AK. True posterior dislocation of subtalar joint: a case report. J Foot Ankle Surg 2003; 42: 363-365
  5. Zimmer TJ, Johnson KA. Subtalar dislocations. Clin Orthop Relat Res 1989; (238): 190-194
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  7. Goldner JL, Poletti SC, Gates HS, et al. Severe open subtalar dislocations. J Bone Joint Surg Am 1995;77-:1075-9
  8. Perugia D, Basile A, Massoni C, Gumina S, Rossi F, Ferretti A. Conservative treatment of subtalar dislocations. Int Orthop 2002;26(1):56-60.
  9. William Yoder, DPM, Patrick Nelson, DPM, Michael Bowen, DPM, Stephen Frania, DPM. Talocalcaneal navicular Dislocation: A review.
  10. Camarda L, Martorana U, D-Arienzo M. Posterior subtalar dislocation. Orthopedics: Case Report. July 2009;32.
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  14. Giannoulis D, Papadopoulos DV, Lykissas MG, Koulouvaris P, Gkiatas I, Mavrodontidis A. Subtalar dislocation without associated fractures: Case report and review of literature. World J Orthop. 2015;6(3):374-9.


Persistent distal sciatic neuropathy following popliteal nerve block in foot and ankle surgery

by Spencer J. Monaco DPM1, Alissa Toth DPM2, Dane K. Wukich MD3pdflrg

The Foot and Ankle Online Journal 9 (3): 1

Popliteal nerve blocks are becoming more popular in patients undergoing foot and ankle surgery. The procedure potentially carries fewer complications and is frequently successful while allowing for earlier mobilization when compared with spinal or epidural anesthesia. Reported complications include paresthesias, pain during needle entry and blood aspiration without risk of dural injury or post procedure headache. We present two patients who underwent a popliteal nerve block for a foot and ankle surgery who developed mixed sensory and motor neuropathy that did not fully resolve within their follow up period.

Key words: popliteal nerve block, foot and ankle surgery, sciatic nerve

ISSN 1941-6806
doi: 10.3827/faoj.2016.0903.0001

1,2 – Resident Physician, University of Pittsburgh Medical Center, Podiatric Residency Program, Pittsburgh PA
3 – Professor of Orthopaedic Surgery, Division of Foot and Ankle Surgery, Pittsburgh PA
* – Corresponding author:

Operative and postoperative analgesia has been provided in varying forms which include general anesthesia, spinal or epidural anesthesia, local anesthesia with IV sedation, and peripheral nerve block [1]. Popliteal nerve blocks are becoming more popular in patients undergoing foot and ankle surgery, allowing for earlier mobilization compared with spinal or epidural anesthesia. As a matter of fact, they are being increasingly performed by foot and ankle surgeons rather than by an anesthesia service [5]. The popliteal nerve block was first described by Gaston Labat in 1922 and can be administered from a posterior or lateral approach, with or without the assistance of ultrasound or nerve stimulation. It is believed that the anesthetic interferes with the sodium and potassium channels thus interfering with the action potential [1].

Borgeat et al retrospectively evaluated 1001 patients and reported on complications such as paresthesias, pain during anesthetic administration and blood aspiration [2]. They concluded the procedure is frequently successful and causes few complications.

In 2014, a study reviewing 143 popliteal blocks performed by podiatric surgical residents showed no postoperative complications but an overall success rate of only 76.2% [5]. The purpose of this paper is to present two patients who developed persistent mixed sensory and motor neuropathic syndromes from a popliteal nerve block following a foot and ankle surgical procedure that were still present at final follow up.

Case 1

A 46 year old female presented to our foot and ankle clinic in regards to a right foot drop. She underwent a peroneal tendon repair 8 months prior at an outside facility. She was able to walk with a limp before her surgery however, is now unable to put her foot flat on the ground. During her procedure a calf tourniquet was used for 30 minutes at a setting of 350 mmHg. She received a popliteal nerve block without the use of ultrasound or nerve stimulation. The patient reported the block did not work and she was able to feel her leg and foot before surgery.


Figure 1 Clinical photograph of 25 degrees plantarflexion.

Upon presentation to our clinic, she complained of paresthesias including tingling in her entire foot and numbness in the S1 nerve distribution. She tried multiple custom made ankle and foot orthotics with no relief.  She has past medical history of psoriatic arthritis. Past surgical history includes right finger soft tissue mass excision and hysterectomy. Medications include meloxicam and gabapentin.

Physical examination revealed an alert and oriented female with a BMI of 25. Overall her pain was 6 out of 10. She had palpable pedal pulses. Light touch and vibratory sensation were intact. Achilles and patellar deep tendon reflexes were also intact. Her ankle was fixed at 25 degrees of plantarflexion which was non-reducible and did not improve with knee flexion (Figures 1 and 2). Manual muscle testing demonstrated 3/5 inversion and eversion, 4/5 digital plantarflexion and dorsiflexion and 3/5 ankle dorsiflexion.  Mid-calf circumference was six centimeters less than the non-affected side. Electromyography (EMG) and nerve conduction velocity (NCV) studies showed acute axonal degeneration in muscles innervated by the tibial, superficial peroneal, lateral plantar and deep peroneal nerves consistent with a distal sciatic neuropathy.  A 3T MRI scan was completed which showed signal intensity of the posterior tibial muscle and soleus muscles indicating atrophy. She underwent a Z lengthening of the triceps surae and posterior ankle joint capsule release to correct the equinus deformity (Figure 3). At 4-month follow up, the patient’s foot remained at 90 degrees relative to the leg, however, had continued neuropathic symptoms. She was referred to peripheral nerve surgery for possible neurolysis and nerve grafting.


Figure 2 Clinical photograph illustrating equinus deformity during weightbearing.


Figure 3 Intraoperative photograph of Z lengthening with posterior ankle joint capsule release.

Case 2

A 17-year-old male sustained a 5th metatarsal zone 2 injury of his right foot and was treated with percutaneous intramedullary screw fixation. He received a preoperative regional nerve block by the anesthesia service. Ultrasound or nerve stimulation was also not used.  During his procedure a calf tourniquet was used for 45 minutes at 250 mmHg. During his postoperative course, he developed ipsilateral calf and intrinsic foot muscle atrophy along with pain he described as “pins and needles.” He had an unremarkable past medical history. He had no other past surgical history.

The patient’s BMI was 26.9. Physical examination revealed impaired sensation in the peroneal and tibial nerve distributions at the pedal level. Strength testing revealed 4/5 strength of the tibialis anterior and gastrocnemius muscles. Extensor hallucis longus was 4/5 with full strength to hamstrings, quadriceps, and adductors. EMG/NCV studies showed chronic right sciatic neuropathy distal to the biceps femoris and semimembranosus muscles at 12 months following surgery as well as severe axon loss to intrinsic foot muscles. He was referred to physical medicine and rehabilitation. He was recommended custom orthotics and exercises as well as a home transcutaneous electrical nerve stimulation unit. He was also given B12 vitamin complex and fish oil. His symptoms improved with the exception of intrinsic muscle function and tone, which was persistent at 2 year follow up.


Motor and/or sensory neuropathy from a popliteal nerve block is uncommon for patients undergoing foot and ankle surgery with reported incidence of between 1.26% and 5% [1-2]. In a recent retrospective study of 1014 patients who had a popliteal block for foot and/or ankle surgery, the overall success rate was 97.3%. 135 patients reported varying manifestations of neuropathic complications.  Eight of these patients retrospectively reviewed developed exclusively motor deficits, 118 exclusively sensory deficits and the remaining nine patients reported mixed sensory and motor deficits.

At final follow up, 14 patients had residual neuropathic symptoms. No statistical significance was found between tobacco use, diabetes, tourniquet location or time, block procedure techniques, single or continuous blocks, or ultrasound or nerve stimulation [1].

A retrospective study of popliteal nerve blocks for hallux valgus surgery showed an incidence of 1.91% for 157 consecutive hallux valgus surgeries. 44% of the blocks were performed with ultrasound in conjunction with nerve stimulation [4].

In 2012, Gartke et al prospectively studied the effects of continuous rather than single shot popliteal blocks in foot and ankle surgery [3]. The study showed a 41% incidence at 2 weeks that decreased to 24% at 8 months. In this study, only 4% of the patients manifested symptoms to warrant referral to a neurologist or pain specialist.  

Although regional nerve blocks prior to foot and ankle surgery are generally effective and obviate the negative side effects of opioids or other sedation, careful patient counseling should be planned prior to the procedure. Continuous popliteal nerve blocks may have a higher incidence of transient postprocedural neuropathy versus single shot blocks. Although the majority of neuropathies are isolated sensory deficits that resolve in a period of months, we present two cases of mixed sensorimotor deficits that persisted beyond final follow up. Interesting, both patients that developed distal sciatic neuropathy did not have guidance from either an ultrasound or nerve stimulator during the nerve block. Moving forward, all patients at our institution undergoing a popliteal nerve block have either ultrasound guidance and/or nerve stimulation which is performed by the anesthesia service.


  1. Anderson JG, Bohay DR, Maskill JD, et al. Complications After Popliteal Block for Foot and Ankle Surgery. Foot Ankle Int. 2015;36(10):1138-43.
  2. Borgeat A, Blumenthal S, Lambert M, Theodorou P, Vienne P. The feasibility and complications of the continuous popliteal nerve block: a 1001-case survey. Anesth Analg. 2006;103(1):229-33.
  3. Gartke K, Portner O, Taljaard M. Neuropathic symptoms following continuous popliteal block after foot and ankle surgery. Foot Ankle Int. 2012;33(4):267-74.
  4. Hajek V, Dussart C, Klack F, et al. Neuropathic complications after 157 procedures of continuous popliteal nerve block for hallux valgus surgery. A retrospective study. Orthop Traumatol Surg Res. 2012;98(3):327-33.
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