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Temporary bridge plating of the medial column in Chopart and Lisfranc injuries

by Alaa Mansour DPM1*, Lawrence Fallat DPM, FACFAS2✛

The Foot and Ankle Online Journal 10 (1): 5

Severe traumatic injuries isolated to the midfoot region involving combined fracture and dislocation of the Chopart and Lisfranc joints are unique and uncommon. In the incidence of crush injuries and comminution with subsequent medial column shortening, maintaining anatomic reduction with rigid stabilization may pose a challenge to the surgeon. Bridge plating is generally used to maintain length, alignment and stabilize comminuted fractures by spanning across unaffected bones or joints, leaving the fracture area undisturbed. This technique reduces devitalization of fragments and promotes a healing environment. Temporary bridge plating  over violated joints serves to maintain reduction and relative congruence. A case is presented of a 25-year-old male with a dislocated and comminuted navicular and Lisfranc fracture following a motorcyle accident.

Keywords foot trauma, fracture dislocation, locking plate, medial column shortening, midfoot crush injury, navicular dislocation

ISSN 1941-6806
doi: 10.3827/faoj.2017.1001.0005

1 – Resident, Beaumont Hospital – Wayne, Wayne, MI
2 – Program Director, Podiatric Surgical Residency Program, Beaumont Hospital – Wayne, Wayne, MI
* – Corresponding author: alaa.mansour3@gmail.com
✛ – Conflict of interest: Consultant to Depuy-Synthes


Crush injuries to the midfoot are uncommon accounting for 6% of traumatic midfoot injuries, with midtarsal joint (Chopart) fracture-dislocations being the most severe [1-4]. In a review of 155 patients, 72% of midfoot injuries were caused by traffic accidents with 52% and 17% caused by car and motorcycle accidents, respectively [2]. Simultaneous fractures occur in approximately 75-90% of Chopart fractures, with only 10-25% percent of injuries being purely ligamentous [4, 5]. These injuries generally occur with high-energy trauma and are at an increased risk for soft tissue compromise and compartment syndrome. This may lead to long-term morbidity and functional impairment if misdiagnosed and not properly treated.

Midfoot injuries typically result in multiple intra-articular tarsal fractures with the failure of key supporting structures, such as bony articulations and ligamentous attachments. When structures in the joint complex begin to fail, increased stress is transferred to the surrounding joints leading to subsequent loss of joint function. Failure of the talonavicular joint (TNJ) leads to flattening of the longitudinal arch, abduction of the forefoot, and a gradual valgus deformity of the subtalar joint resulting in a painful flatfoot [6].

Pinney and Sangeorzan classified fractures of the navicular body into three types. In type I, the fracture line is transverse in the coronal plane with a dorsal fragment. In type II, the fracture line passes from dorsolateral to plantarmedial with the large fragment being dorsomedial. In type III, navicular fractures are comminuted and often result in medial disruption at the naviculocuneiform joint (NCJ) with lateral displacement of the foot and subluxation of the lateral column [7].

Comminuted fracture dislocations of the navicular and cuboid, in particular, can result in medial and lateral column shortening presenting a challenge for the surgeon to restore the length and congruity of the joint. Typically, the treatment of choice for comminuted fractures involves stabilizing techniques such as bridge plating and external fixation. However, comminuted fractures specific to the midfoot have also been addressed through a variety of methods including closed reduction with crossing Kirschner-wire (k-wire) fixation, open reduction with k-wire or screw fixation, primary arthrodesis, external fixation and temporary bridge plating. Of these fixation types, bridge plates are advantageous because they allow the surgeon to maintain the length of the bones while also stabilizing the bony fragments too small for individual fixation. Bridge plating functions as an internal splint by providing fixation to both the proximal and distal intact bone creating a “bridge” over the site of comminution. The use of temporary bridge plating has been discussed in the literature as an alternative to external fixation to span comminuted fractures without extensive periosteal stripping or vascular compromise [8,9].  After healing is complete, the bridge plate is removed to restore joint motion.

Case Report

A 25-year-old male presented to the emergency department after crashing his motorcycle while intoxicated into a cement barrier traveling at a speed of 40-50mph. On physical examination, neurovascular status was intact and there were no open wounds or signs of compartment syndrome. Initial radiographs revealed a comminuted and dorsally dislocated navicular fracture along with significant disruption of the Lisfranc and midtarsal joint (Figure 1). Further detail was visualized in the computerized tomography scan (CT) revealing multiple fractures, which included a Type III intra-articular, comminuted, navicular fracture with a Chopart dislocation, a comminuted cuboid fracture, a Lisfranc dislocation, cuneiform fractures, and fractures of metatarsal bases two, three and four (Figure 2). Additionally, medial and lateral column shortening was evident with subsequent disruption of the talonavicular, calcaneocuboid (CCJ), and Lisfranc joints. Closed reduction was attempted in the Emergency room but was unsuccessful. He also sustained a nasal and left femur fracture.

Figure 1A Lateral view reveals dorsally dislocated and comminuted navicular fracture.

Figure 1B Anterior-Posterior [AP] view reveals comminution of the navicular, cuboid, Lisfranc fracture dislocation, and shortening of the medial column.

Figure 2A CT sagittal view of the comminuted and displaced cuboid fracture.

Figure 2B Coronal CT image depicting comminution of the navicular

The patient initially underwent open reduction and internal fixation of his femur by an orthopedic surgeon. One week later he was taken back to the operating room with the primary goal of reducing the navicular bone, restoring the length of the medial and lateral column, as well as reducing and fixating the Lisfranc dislocation of metatarsals 2, 3, and 4. The patient was placed on the operating table in the supine position and a pneumatic ankle tourniquet was inflated to 225 mmHg for hemostasis.

Prior to the incision, the area overlying the dislocated navicular was marked with a metallic marker under fluoroscopy. The dorsally displaced navicular fragment was then successfully reduced in a closed fashion with distraction of the foot in a dorsiflexed-inverted position. In order to appropriately restore the length of the medial column, it was deemed necessary to perform open reduction with internal fixation. A linear longitudinal incision was made dorsomedial to the TNJ and was carried distally past the first metatarsal cuneiform joint. Dissection revealed a large hematoma and rupture of the joint capsule above the TNJ and NCJ.  The navicular was severely comminuted and the fracture fragments were rotated such that the articular surface was pointing away from the joint surfaces of the talus and cuneiforms. The large fracture fragments were then reduced into correct anatomic orientation, but the degree of comminution still yielded an unstable medial column. To span the area of comminution and stabilize the medial column, the bridge plate technique was used.  The fracture fragments were temporarily stabilized with 0.062 inch K-wires and a 4.5mm cortical lag screw was inserted from dorsal to plantar in the center of the navicular fragment to maintain reduction and prevent dorsal displacement of the main body. A 12-hole plate was then temporarily fixated with olive wires and applied to the medial column spanning the talus, navicular and medial cuneiform (Figure 3). A total of ten 3.5mm fully-threaded locking screws were placed into the plate.

Figure 3A AP view after open reduction and internal fixation of the medial and lateral column utilizing a bridge plate, Lisfranc trans-articular screws, and a lateral column positional “bridge screw”.

Figure 3B Lateral view reveals restoration of the longitudinal arch with reduction and stabilization of the previously dislocated navicular fracture.

Closed reduction was performed with percutaneous fixation of the Lisfranc dislocation of metatarsals two, three and four using two 4.5 mm cannulated cortical screws. The first screw was oriented from the lateral aspect of the third metatarsal base into the second cuneiform, and a second screw was oriented from the lateral aspect of the fourth metatarsal base into the third cuneiform (Figure 3).

To maintain reduction and prevent shortening of the lateral column, a 5.5 mm fully-threaded cannulated “bridge screw” was inserted percutaneously into the lateral aspect of the base of the fifth metatarsal, through the center of the cuboid to end in the anterior calcaneus (Figure 3). The purpose of this screw was not to provide compression but simply to maintain the position and length of the lateral column by bridging the comminuted cuboid.

Post-operatively, the patient was placed into a well-padded posterior splint to accommodate for swelling that typically occurs after a traumatic injury such as this. The patient was instructed to be non-weight bearing on the affected extremity with the assistance of a walker.

After two weeks the patient returned for his first follow-up visit. The patient rated his pain as 2/10 and well controlled with oral pain medication. At this time, the patient opted for a Controlled Ankle Movement (CAM) boot instead of a cast due to his uninsured status. The patient was instructed to remain non-weight bearing and to keep the CAM boot on at all times.

At the six-week follow-up, the patient had disregarded our instructions and started weight bearing with the CAM boot. The patient presented to our clinic complaining of sharp heel pain both medially and laterally only while ambulating. The patient refused to have radiographs taken due to the cost. The patient was then lost to follow-up for some time.

At the four-month follow-up, the patient returned to the clinic stating that he stopped wearing the CAM boot after the last visit and returned to full-weight bearing. Fifteen weeks postoperatively, he presented to the emergency department secondary to pain in his foot. Radiographs revealed osseous union of all fracture sites with no displacement. However, the positional screw in the lateral column, as well as two additional screws within the medial column bridge plate were noted to be broken.

The patient underwent removal of hardware five months after the date of the original surgery. Intra-operatively, the navicular, and the medial and lateral columns were noted to be consolidated and in a rectus position with an intact medial longitudinal arch. Post-operatively, after the hardware removal, the patient was placed in a below-knee cast. After missing several appointments, the patient followed up one-month later stating that he removed his own cast with a hacksaw three days after surgery. The patient was placed into a CAM boot and instructed to decrease activity for two weeks before transitioning into regular shoe gear. Eight weeks after the hardware removal, the patient was back in regular shoe gear and denied any pain. One year from the original injury, the patient was satisfied with the outcome and was pain-free without any activity limitations.

Discussion

Midfoot injuries are uncommon because the corresponding joints contain strong ligamentous structures that are typically resistant to disruption. When these ligaments are disrupted or when fractures occur, dislocations may result to both the medial and lateral column, which may result in instability and shortening of the medial longitudinal arch or lateral column [10]. Consequently, shortening of the medial column can result in pes cavus while shortening of the lateral column can result in pes planus [10]. Main and Jowett determined that outcomes following midfoot injuries are dependent on the stability of the medial column [4]. The outcome for crush injuries in their study was only fair in 75% of cases following open or closed reduction with plaster cast immobilization [4].

Most of the crush injuries involving the navicular tend to be intra-articular at both the proximal and distal aspects because of the narrow anatomic shape of the bone [7]. Despite anatomic reduction, a satisfactory outcome may be hindered by cartilage damage caused by the intra-articular fracture. Pinney and Sangeorzan recommend restoration of at least 60% of the articular surface of the TNJ to prevent subluxation following fracture healing [7].

Temporary bridge plating allows for relative fracture-site stability despite severe comminution and thus has many advantages. It supports indirect healing and allows for adequate reduction without having to reduce and fixate each individual fragment. Bridge plates also restore length and alignment by spanning across unaffected bones, thus leaving the fracture area undisturbed. It also preserves the soft tissue attachments and blood supply by limiting extensive dissection needed for adequate exposure.  In this case presentation, the plate was used to successfully bridge the medial column from the talar neck to the first metatarsal. The cuboid was also stabilized with a positional screw to restore the length of the lateral column.  Schildhauer, et al., utilized a bridge plate in seven patients to span medial column injuries. All seven cases went on to heal and maintain proper length and alignment of the medial column [8].

On the other hand, bridge plating across joints, especially in the midfoot, restricts motion significantly. Astion, et al., has shown that arthrodesis of the TNJ has shown to dramatically decrease joint motion at the subtalar and calcaneocuboid joints [11]. Therefore, it is important to remove the plate and restore motion at the TNJ after the fracture is healed. Schildhauer, et al., recommend removal of the plate after 4-9 months to restore function to the TNJ and STJ [8].

A possible complication with bridge plating as with any treatment of severe fractures is wound dehiscence. Open reduction and internal fixation should be delayed in the presence of extensive swelling or soft tissue compromise. Excessive soft tissue dissection and exposure of fracture fragments should be limited because the soft tissue structures are the vascular envelope responsible for nurturing and promoting the healing of the injury. In a recent study, van Koperen, et al., indicates that one of the drawbacks of bridge plating is extensive dissection during plate placement and removal, which can increase the risk of wound complications. However, in their study bridge plating did not lead to more wound complications when compared with trans-articular fixation [12]. Atraumatic technique and understanding of surgical anatomy are important to prevent devascularization and limit post-surgical complications.

Another complication with comminuted fractures is avascular necrosis. Sarrafian describes the blood supply to the navicular as being radial in its arrangement, with the central body being relatively avascular [13]. Sangeorzan, et al., found that after open reduction and internal fixation of displaced navicular body fractures, six out of twenty-one [29%] patients developed radiographic signs of avascular necrosis, however, only one lead to collapse [14].  With appropriate fixation and understanding of the limitations of bridge plating, one can avoid complications such as non-union and avascular necrosis.

Temporary bridge plating is a viable treatment option for comminuted midfoot fractures that span joints without extensive dissection or vascular compromise.  It allows for relative fracture-site stability despite severe comminution and supports indirect healing without having to reduce and fixate each individual fragment. Bridge plates also restore length and alignment by spanning across unaffected bones, thus leaving the fracture area undisturbed. Overall, a good outcome was achieved using the bridge plate even with our patient bearing weight early, he was satisfied with the outcomes and returned to his previous activity level.

References

  1. Didomenico LA, Thomas ZM. Midfoot crush injuries. Clin Podiatr Med Surg. 2014;31(4):493-508.
  2. Richter M, Wippermann B, Krettek C, Schratt HE, Hufner T, Therman H. Fractures and fracture dislocations of the midfoot: occurrence, causes and long-term results. Foot Ankle Int. 2001;22(5):392-8.
  3. Makwana NK, van Liefland MR. Injuries of the midfoot. Current Orthopaedics 19:231-242, 2005.
  4. Main BJ, Jowett RL. Injuries of the midtarsal joint. J Bone Joint Surg Br 57:89-97, 1975.
  5. Richter M, Thermann H, Huefner T, Schmidt U, Goesling T, Krettek C. Chopart joint fracture-dislocation: initial open reduction provides better outcome than closed reduction. Foot Ankle Int. 2004;25(5):340-8.
  6. Sammarco, VJ. The talonavicular and calcaneocuboid joint: Anatomy, biomechanics, and clinical management of the transverse tarsal joint. Foot Ankle Clin. 9:127-45, 2004.
  7. Pinney SJ, Sangeorzan BJ. Fractures of the tarsal bones. Orthop Clin North Am. 2001;32(1):21-33.
  8. Schildhauer TA, Nork SE, Sangeorzan BJ. Temporary bridge plating of the medial column in severe midfoot injuries. J Orthop Trauma. 17:513-520, 2003.
  9. Cammack PM, Donahue MP, Manoli A. The bridge and barrel hoop plates as alternatives to external fixation techniques in the foot and ankle. Foot Ankle Clin. 2004;9(3):625-36, xi.
  10. Dhillon MS, Nagi ON. Total dislocations of the navicular: are they ever isolated injuries? J Bone Joint Surg Br. 81:881-885, 1999.
  11. Astion DJ, Deland JT, Otis JC, Kenneally S. Motion of the hindfoot after simulated arthrodesis. J Bone Joint Surg Am. 1997;79(2):241-6.
  12. Van koperen PJ, De jong VM, Luitse JS, Schepers T. Functional outcomes after temporary bridging with locking plates in Lisfranc injuries. J Foot Ankle Surg. 2016;55(5):922-6.
  13. Sarrafian SK. Anatomy of the Foot and Ankle, pp 340-342, JB Lippincott, Philadelphia, 1983.
  14. Sangeorzan BJ, Benirschke SK, Mosca V, Mayo KA, Hansen ST. Displaced intra-articular fractures of the tarsal navicular. J Bone Joint Surg Am. 1989;71(10):1504-10.

Immediate Ambulation after a First Metatarsophalangeal Joint Fusion using a Locking Plate: Technique and case reports

by Robert M Greenhagen, DPM1 , Shelly A Wipf, DPM1, Adam R Johnson, DPM2,
Patrick J Nelson, DPM3, Nicholas J Bevilacqua, DPM4

The Foot and Ankle Online Journal 3 (4): 2

Purpose: Arthrodesis of the first metatarsophalangeal joint (MTPJ) is a predictable procedure to relieve pain and dysfunction of the first MTPJ. Many fixation techniques have been described. The authors present two cases in which a locking plate was successfully used for first MTPJ fusion. The patients began immediate weight-bearing post-operatively without a delay in union, hardware failure, or malalignment.
Methods: A retrospective chart and radiographic review of a 53 year-old male and a 59 year-old female was performed. Serial radiograph was taken to assess fusion at the arthrodesis site.
Procedures: Cartilage was resected from the head of the first metatarsal and base of the proximal phalanx preserving the curvature of the joint. The joint was placed in the desired position and interfragmental compression was obtained using a cannulated 4.0-millimeter partially threaded screw from proximal medial to distal lateral with all threads crossed the fusion site. A locking plate was then placed on the dorsal aspect of the joint and secured with locking screws proximal and distal.
Results: The patients began ambulating immediately post-operatively with a post-operative shoe. Both patients had successful fusion by 8 weeks with good alignment and intact fixation. Patients returned to regular shoe gear once trabeculation was noted.
Conclusion: These 2 case reports suggest excellent results and immediate ambulation with compression screws and locking plates. This clinical report shows promise in regards to early ambulation using locking plate fixation technique and further studies are encouraged.

Key words: Arthrodesis, first metatarsophalangeal joint, MTPJ fusion, locking plate.

Accepted: March, 2010
Published: April, 2010

ISSN 1941-6806
doi: 10.3827/faoj.2010.0304.0002


Arthrodesis of the first metatarsophalangeal joint (MTPJ) is a predictable procedure to relieve pain and dysfunction of the first MTPJ. The indications for this common procedure include hallux rigidus, rheumatoid arthritis, revision of failed bunion surgery, implant arthroplasty, and Keller procedures, and deformities secondary to neuromuscular disease such as cerebral palsy and poliomyelitis. [1] Fixation techniques vary from crossed Kirschner wires [1], intramedullary Steinman pins [2], intramedullary screws [3-5], crossed lag screws [6], external fixation [7], and plate fixation with interfragmentary screw. [2-8]

Protocols for post-operative ambulation have varied throughout the literature, and there have been numerous reports of early weight-bearing with favorable union rates, albeit most of these studies reported patients ambulating in a rigid post-op shoe or short leg walking cast that eliminated the propulsive phase of gait.2,9-12 To our knowledge, there are currently no reported cases evaluating the use of locking plates for first MTPJ fusion. The purpose of this report is to examine results with immediate ambulation after first MTPJ with compression screws and locking plates.

Case Report 1

A 59 year-old female presented to the foot and ankle clinic with severe pain to the right first MTPJ. She had undergone an Austin bunionectomy previously, and now presented with severely limited and painful joint range of motion. Radiographs were consistent with asymmetric joint space narrowing and degenerative joint disease. (Fig. 1) The patient was informed of the risk, benefits and complications of both the procedure and the new post-operative protocol.

 

Figure 1  Pre-operative radiographs show severe joint space narrowing and sclerotic subchondral changes. (A)  Radiographs at seven weeks show full trabeculation and intact hardware. (B)

Figure 4  The cup portion of the reamer is used first to remove all cartilage from the metatarsal head. (A)

The phalanx is reamed with the cone reamer. By performing the metatarsal head first, more room is made for cumbersome cone reamer. (B) (Illustration by Patrick Nelson, DPM©) 

Informed consent was obtained and the patient underwent a first MTPJ arthrodesis with a compression screw and a four-hole locking plate. Seven weeks after surgery, the patient presented for follow-up in normal footwear with pain free ambulation. Radiographs revealed trabeculation across the fusion site, with good alignment and intact fixation. (Fig. 2)

Case Report 2

A 53 year-old male presented with localized severe pain to his right first MTPJ. The patient had minimal range of motion and radiographs showed significant degeneration and non-uniform narrowing of the joint space. (Fig 2A) The patient exhausted conservative care and desired surgical management. The patient was informed of the risk, benefits and complications of both the procedure and the new post-operative protocol. Informed consent was obtained and the patient underwent a first MTPJ arthrodesis with a compression screw and a four-hole locking plate. (Fig. 2B)

 

Figure 2  Pre-operative radiographs show severe hallux rigidus with diffuse joint space narrowing and flattening of the metatarsal head. (A) Postoperative week eight, osseous union is noted with no signs of hardware failure. (B)

Post-operatively, the patient was placed in a surgical shoe and instructed to ambulate as tolerated. Eight weeks after surgery, the patient presented in normal shoe gear and pain free ambulation. Radiographs showed trabeculation, excellent alignment and intact fixation.

Technique

A dorsal medial incision was made and layered dissection was continued down to the level of the joint. (Fig. 3) Cartilage was resected from the head of the first metatarsal and base of the proximal phalanx preserving the curvature of the joint using a cup and cone reamer. (Fig. 4) The joint was placed in the desired position (slight dorsiflexion and abduction) and interfragmental compression was obtained using a 4.0-millimeter partially threaded cannulated screw. The screw was placed from proximal medial to distal lateral being sure that all threads crossed the joint. (Fig. 5) The alignment of the joint and position of the screw was directly visualized using intra-operative fluoroscopy. The locking plate was placed on the dorsal aspect of the joint and secured with locking screws proximal and distal. (Fig. 6) The wound is closed in layers and a dressing is applied.

Figure 3 A dorsal medial approach is made which allows reaming of the proximal phalanx and first metatarsal head.

 

Figure 4  The cup portion of the reamer is used first to remove all cartilage from the metatarsal head. (A) The phalanx is reamed with the cone reamer. By performing the metatarsal head first, more room is made for cumbersome cone reamer. (B) (Illustration by Patrick Nelson, DPM©)

Figure 5 An interfragmentary screw can be placed from proximal medial to distal lateral. This provides both compression and fixation that does not interfere with the dorsal plate.  We recommend the use of a cannulated screw for simplicity. (Illustration by Patrick Nelson, DPM©)

Figure 6 Dorsal plating of the joint provides rigid fixation of the fusion site.

Patients are placed in a post-operative shoe and instructed to ambulate as tolerated. Patients are transitioned to normal footwear once clinical and radiographic signs of healing are appreciated.

Discussion

Many fixation techniques have been described for first MTPJ arthrodesis. [2-4,6-8,13] The ideal fixation technique for MTPJ arthrodesis should maintain stability and position of the fusion site while osseous union occurs.

A review of the literature favors interfragmentary screw fixation as the strongest construct. Neufeld and colleagues compared memory compression staples, cannulated screws, and a five-hole, one-third tubular plate contoured to fit the arthrodesis site in 21 matched fresh-frozen cadaver specimens. [14]

Each specimen was loaded to failure in a cantilever fashion and an extensometer was used to measure gapping across the arthrodesis site, with failure defined as a 2-mm gap. They found that the crossed cannulated screws and the dorsal plate constructs failed at significantly higher loads than the two compression staples (p<0.029 and p<0.002, respectively). [14] The dorsal plate failed due to bending of the plate in 79% of specimens. While the crossed cannulated screws provided the greatest amount of rigidity, failure occurred when the screw fractured the metatarsal head at the screw-bone interface in all but one specimen.

Curtis and colleagues found interfragmentary screws to be superior to plate fixation due to bending of the plate. [15] They suggested that adding a screw or K wire placed obliquely to the axis of the MTPJ might improve stability. Politi, et al., used synthetic bone models to demonstrate that the most stable technique was an oblique interfragmentary lag screw with a dorsal plate. [16]

There are several problems with conventional plate application. The stability of a plate relies on compression between the plate and the cortical bone, potentially disrupting the periosteal blood supply and inducing porosity of the bone. [17] To apply a screw to a conventional plate, it must be tightened with an axial traction of 1000-2000 Newtons (N), which produces up to 2400 N of friction in a 4-hole plate (co-efficient of friction between metal and bone = 0.4). [18] In addition, plate application to the first MTPJ is fraught with biomechanical disadvantages. The AO (Arbeitsgemeinschaft für Osteosynthesefragen) group recommends that a plate be positioned on the tension side of a bone to create dynamic compression in accordance with the tension band principle.1 In a loaded first MTPJ, the tension side is the convex plantar surface of the joint. Due to the position of the sesamoids, soft tissue structures, and potential complications of plantar incisions, the ideal placement of the plate on the tension side of the joint is not feasible, and the plate must be placed on the concave dorsal or compression side of the joint. Since the plate thus applied cannot supply tension band fixation, it will instead serve a neutralization function to protect the lag screw from shearing, bending, and torsional forces.

The locking plate design overcomes several of the disadvantages of conventional plate fixation and when combined with the use of an interfragmentary lag screw for compression, may provide a construct sufficiently stable to allow early weight-bearing and successful arthrodesis. The screw holes of the locking plate have threads that match the conically threaded undersurface of the screw heads, locking the screw head to the plate and negating the need for the plate to be compressed against the bone, thus minimizing the potential for disruption of the periosteal blood supply. [18,20] The locking mechanism between the screw and the plate prevents toggle and screw back out which may result from micromotion of up to 90% body weight that could be transferred onto the first MTPJ during gait. [21] In addition, the locking properties of the plate and screws render failure impossible unless there is simultaneous pullout of all the screws. [22] Gallentine and colleagues reported the use of locking plate fixation of proximal metatarsal chevron osteotomies, finding that the locking plate was successful in maintaining alignment and position of the first ray in patients who were allowed to bear weight on their heel immediately postoperatively. [23] In a study of synthetic calcaneal fracture models, the stability of plates with locking screws and conventional plates without locking screws was compared. [24] It was shown that the locking plates provided greater stability than the conventional plates with high cyclic loading simulating full weight-bearing.

In an in-vitro study of first metatarsocuneiform arthrodesis, Cohen, et al., argued that one of the shortcomings of the locking plate is that while it is rigid at the screw to plate to bone interface, it provides no compression at the arthrodesis site. [25] The authors of the current case report assert that the addition of the interfragmentary screw at the fusion site allows for compression, obviating the need for compression by the biomechanically disadvantaged plate. In this way, the plate functions to neutralize weight-bearing forces, while avoiding the aforementioned failure at the screw-bone interface by the intrinsic properties of the locking mechanism.

Allowing immediate ambulation after first MTPJ arthrodesis decreases the morbidity of the procedure by reducing disuse atrophy and osteopenia, the risk of deep thrombosis/pulmonary embolism, and inconvenience to the patient. When fixated with adequate internal fixation, the first MTPJ arthrodesis is a stable construct which allows the patient to ambulate immediately postoperatively. This notion has received support throughout the literature. In his early description of first MTPJ fusion in 1952, McKeever recommended weight-bearing in a cut-out shoe at the third or fourth post-operative day, though he noted that he cautioned the patient “very strongly” against placing full weight on the toe for six weeks. [5] Immediate ambulation in a wooden-soled postoperative shoe or short walking boot is the standard of care reported in a major orthopaedic text. [26]

In a retrospective review of 47 first MTPJ arthrodeses, Dayton reported a 100% fusion rate when allowing immediate post-operative ambulation with a standard surgical shoe, restricting weight to the heel or lateral aspect of the foot. [9] A randomized, prospective study of 61 cases found a 97% fusion rate for the early weightbearing group and a 93% fusion rate for the delayed weightbearing group, suggesting no difference in radiographic union or clinical outcome between patients who began ambulating two to four days post-operatively and those who remained non-weightbearing for four weeks. [12] Most authors recommend the use of a post-operative shoe or a CAM boot to eliminate the propulsive phase of gait, thus decreasing the chance for fixation failure. Young and colleagues compared three types of post-operative boots with a fiberglass cast in a cadaver model using strain gauges in the first MTPJ joint and simulated weightbearing. [27] They found that the removable cast boots provided the same, and in one type, even more reduction of force across the arthrodesis site than a traditional fiberglass cast.

The exact amount of force that a first MTPJ arthrodesis site can tolerate before failing is still unknown. The authors recognize that in certain situations, the force to failure may be reduced, such as revision arthrodeses utilizing bone grafts, cases in which less than optimal fixation is achieved, or large patient habitus. In such cases, an early weightbearing protocol may not be appropriate.

Further limitations of this case report include the small number of cases, selection and evaluation bias. The small number is due to the fact that all patients were directly seen by the junior authors. The senior author may have had other patient’s that would have satisfied the selection criteria, but were not included. This may have lead to an unintended selection bias. All patients and radiographs were evaluated by the senior author. Evaluation bias may have also occurred. The patients’ digital radiographs are included to address this concern. While the authors recognize these limitations, we do not advocate a change in the standard of care based solely on limited case studies alone and further studies are needed.

Conclusion

The authors have presented 2 cases of early ambulation following first MTPJ arthrodesis with a successful result using a locking plate with an interfragmentary screw. This clinical report shows promise for first MTPJ with regard to early and immediate ambulation following first MTPJ fusions.

References

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2. Smith RW, Joanis TL, Maxwell PD. Great toe metatarsophalangeal joint arthrodesis: a user-friendly technique. Foot Ankle 1992 13(7): 367-77.
3. Hansen ST. Functional reconstruction of the foot and ankle. 2000, Philadelphia: Lippincott Williams & Wilkins. xviii, 525
4. Castro MD, Klaue K. Technique tip: Revisiting an alternative
method of fixation for first MTP joint arthrodesis. Foot Ankle Int 2001 22(8): 687-688.
5. McKeever DC. Arthrodesis of the first metatarsophalangeal joint for hallux valgus, hallux rigidus, and metatarsus primus varus. JBJS 1952 34A(1): 129-134.
6. Turan I, Lindgren U. Compression-screw arthrodesis of the first metatarsophalangeal joint of the foot. Clin Orthop Rel Res 987 (221): 292-295.
7. Harrison MHM, Harvey FJ. Arthrodesis of the first metatarsophalangeal joint for hallux valgus and ridigus. JBJS 1963 45A (3): 471-480.
8. Goucher NR, Coughlin MJ. Hallux metatarsophalangeal joint arthrodesis using dome-shaped reamers and dorsal plate fixation: A prospective study. Foot Ankle Int 2006 27(11): 869-876.
9. Dayton P, McCall A. Early weightbearing after first
Metatarsophalangeal joint arthrodesis: a retrospective observational case analysis. J Foot Ankle Surg 2004 43(3): 156-159.
10. Sage RA, Lam AT, Taylor DT. Retrospective analysis of
first metatarsal phalangeal arthrodesis. J Foot Ankle Surg 1997 36(6): 425-429 (discussion 467).
11. Flavin R, Stephens MM. Arthrodesis of the first
metatarsophalangeal joint using a dorsal titanium contoured plate. Foot Ankle Int 2004 25(11): 783-787.
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Address correspondence to: Robert M. Greenhagen, DPM, UPMC Podiatric Residency Program, Pittsburgh, PA.

Podiatric Residents, UPMC Podiatric Residency Program, Pittsburgh, PA
Podiatric Resident, Hennepin County Medical Center, Minneapolis, MN
Podiatric Resident, Saint Vincent Charity Hospital, Cleveland, OH
Associate Medical Director, Amputation Prevention Center, Valley Presbyterian Hospital, Los Angeles, CA

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