Tag Archives: Subtalar dislocation

Coronal plane talar body fracture associated with subtalar and talonavicular dislocations: A case report

by Barıs YILMAZ, MD1, Baver ACAR, MD2, Baran KOMUR, MD3, Omer Faruk EGERCI, MD2, Ozkan KOSE MD, FEBOT, Assoc. Prof.2pdflrg

The Foot and Ankle Online Journal 9 (4): 3

Talar body fractures usually occur as a result of high-energy trauma and variety of different type of talar fractures may occur. Most of the talar fractures are included in classification systems.  Even though it is possible to observe talar fractures with concomitant dislocations, together by reason of their functional relationship with the tibiotalar, subtalar and talonavicular joints, such observations are only addressed in literature in the form of case studies.  The present case, exhibiting talar body fracture in the coronal plane observed together with subtalar and talonavicular dislocations, is of importance due to the rarity of the diagnosis, treatment, and 2-year follow-up results.

Keywords: Talar body fracture, subtalar dislocation, talonavicular dislocation, talus

ISSN 1941-6806
doi: 10.3827/faoj.2016.0904.0003

1 – Fatih Sultan Mehmet Training and Research Hospital, Orthopedics and Traumatology Department, Istanbul, Turkey
2 – Antalya Training and Research Hospital, Orthopedics and Traumatology Department, Antalya, Turkey
3 – Kanuni Sultan Suleyman Training and Research Hospital, Orthopedics and Traumatology Department, Istanbul, Turkey
* – Corresponding author: drozkankose@hotmail.com


Talar fractures and fracture-dislocations are uncommon compared to other injuries to the ankle because of the location of the talus in the ankle joint and its anatomical structure. Talar fractures represent 0.32% of all fractures, 2% of lower-extremity fractures, and 5-7% of ankle fractures. However, the talus is the second most frequently fractured bone of all the tarsal bones[1, 2]. In the literature, the incidence of talar body fractures has been reported to be in the range of 7-38% of all talus fractures, and as 0.062% of all body fractures [3, 4].

The majority of these injuries occur as a result of high-energy trauma [5, 6]. The lack of muscle attached to the talus and that a large part of the surface is covered with articular cartilage create a predisposition to talus fractures and concurrently observed dislocations. The treatment of talar body fractures is rather problematic due to the complex anatomy and the diversity of fracture patterns [7, 8]. Treatment becomes even more difficult when these fractures are accompanied by dislocations of adjacent joints. The case presented in this paper emphasizes the importance of emergent open or closed reduction and stable fixation with lag screws and Kirschner wires.

The concurrency of talar body fractures specifically with dislocations of adjacent joints has been addressed with only a few case studies in literature. This case study presents a subtalar and talonavicular joint dislocation of a talar body fracture in the coronal plane and is of paramount significance in that it was treated with open reduction and internal fixation and the clinical follow-up results of 2 years are available.  

Case report

A 32-year-old male was brought to our Emergency Department after sustaining a motorcycle accident with complaints of intense pain and deformity of the right ankle. On physical examination, the ankle was seen to be in an inverted position and there was distinctive deformity accompanied by local paleness arising from skin tightness on the lateral side (Figure 1). The neurovascular examination results were normal. The patient had no accompanying additional injuries. Direct radiographs of the ankle revealed a talar body fracture accompanied by subtalar and talonavicular dislocations (Figure 2). Under conscious sedation, closed reduction was attempted twice in the Emergency Room with no success.  Computed Tomography (CT) was performed and demonstrated a coronal plane talar body fracture associated with subtalar and talonavicular dislocations. A distal fragment of the talus was dislocated, twisted and locked (Figure 3). Thereafter, open reduction and internal fixation of the fracture was planned.

fig1

Figure 1 Clinical image of the case in ED.

fig2

Figure 2 Pre-operative radiographic evaluation of the case.

fig3

Figure 3 Pre-operative CT scan.

Once the surgical preparations had been completed, the patient was taken to the operating room approximately 3 hours after the trauma. Under spinal anesthesia and tourniquet application, an anterolateral incision was used to expose the fracture. The talar head was observed to be locked in the form of a button and a hole in the anterior capsule.  The capsule was retrieved from the talar head and reduction was secured. The talus was fixed with two cannulated screws. The subtalar and talonavicular joints were seen to be unstable, and could be dislocated with a weak inversion strain. Therefore, both the subtalar and talonavicular joints were fixed with K-wires (Figure 4). The achievement of anatomic reduction of both the fracture and the subtalar and talonavicular reduction was monitored postoperatively through a CT scan.  The patient was discharged from the hospital with a short leg brace on the 2nd postoperative day.  The sutures were removed on the 20th day and the K-wires were removed and active ankle exercises were started in the 6th week of follow-up. Full weight bearing was started in the 8th week following the observation of complete healing of the fracture.

fig4

Figure 4 Post-operative radiographs.

The final clinical and radiological follow-up was performed in the second postoperative year (Figure 5). The patient had already returned to work and social life and his AOFAS score was 87 with no significant finding of arthrosis or any other complaint.

fig5

Figure 5 Post-operative CT examination of the case.

fig6

Figure 6 Radiographic evaluation of the case 2 years postoperatively.

Discussion

Fractures of the Talus typically involve the tibiotalar joint. In their simplest clinical forms, they can be classified as fractures of the talar head, talar neck, talar body, and talar process.  In the AO/OTA classification, however, talus fractures are defined as extra-articular fractures covering neck fractures and avulsion fractures, partial intra-articular fractures covering split or compression fractures, and intra-articular fractures divided into non-displaced, displaced and segmental fractures. The distinction between talar body and neck fractures is of great importance.  A relevant evaluation defined body fracture as a case with the fracture line lying proximal to the lateral process of the talus and neck fracture as a case with the fracture line lying distal to the lateral process of the talus [9, 10].

Talar body fractures have various classifications.  The generally utilized Sneppen classification divided these fractures into five main headings: Type I, osteochondral or transchondral; Type II, coronal, sagittal horizontal, non-segmental; Type III posterior tubercle; Type IV lateral process; and Type V, crush fractures [11]. The Fortin classification defines talar body fractures under three headings: Type 1, talar body fracture on any plane; Type 2, talar process or tubercle fracture; or Type 3 compression or impaction fracture of the talar body [12]. Apart from these headings, these fractures involving the talar dome can also be classified as sagittal, coronal, transverse or segmental fractures depending on the main fracture line. Certain types of fractures and fracture-dislocations not included in the aforementioned fracture classifications can at times be provided in the literature as case reports [13-18]. Identification and classification efforts are still ongoing for these fractures and accompanying dislocations [19]. However, there are some authors who argue that these means of classification do not contribute to the selection of suitable treatment or treatment results [2, 8, 12, 20]. The current case was defined as a talar body fracture on the coronal plane accompanied by subtalar and talonavicular dislocations outside the scope of these classifications. Therefore, these types of fracture-dislocations can be indicated as a rare injury where the fracture type has been classified in literature without any dislocation type specified.  

The mechanism of injury in talar body fractures is generally defined as the exposure of the talar region to axial load or shear forces between the tibia and calcaneus  [21]. This frequently occurs in motorcycle accidents, as in the current case, or incidents of individuals falling from height.  Moreover, these fractures may be accompanied by calcaneus, tibia and talar neck fractures since most of them are induced by high-energy injuries. The observation of dislocations and ligament injuries in various adjacent joints is not surprising with such a mechanism of injury. As an example, a case of medial total subtalar dislocation was reported without a fracture in the ankle [22]. Similarly, another case was defined as a talar body fracture accompanied by anterior talofibular ligament and peroneal longus tendon injuries [23]. Although the literature does not include a high number of series pertaining to dislocations observed together with talar body fractures, a series of 23 talus fractures provided the finding of 7 peritalar dislocations [24]. Adjacent joint fractures accompanying talar body fractures are addressed in the literature with only a few cases [13-18].

Talus fractures can be diagnosed through standard radiographies in general.  However, adjacent joint dislocations clearly add difficulty to the diagnosis of such fractures.  Hence, a good radiological evaluation from the beginning is of great value for prospective surgical planning.  At this stage, CT is of extreme importance to undertake a complete evaluation of the structure of the fracture and to guide the course of treatment.  At times, MRI might be required for the additional evaluation of soft tissue injuries in surrounding ligaments and tendons.

Early emergency reduction should be performed for all fracture-dislocations of the talus with a view to preventing soft tissue damage and not to disrupt the circulation in the talus.  Specifically displaced talar neck and body fractures should be treated with open reduction and stable internal fixation in the early stage.  Closed or percutaneous reduction may be attempted immediately after sufficient analgesia and relaxation.  However, repeated unsuccessful attempts at reduction may increase the damage in fracture-dislocations with already severe damage in soft tissues. However, open reduction is mandatory for locked dislocations, as in the present case or for dislocations with soft tissue in between which cannot be managed with close reduction. If a patient cannot be taken into open reduction for patient-related or other reasons such as in the case of polytrauma patients, the fracture should undergo initial reduction through minimally invasive methods to the extent possible and then be fixed with Kirschner wires [25]. As is the case in other open fractures, open talus fractures require surgical intervention [26]. Furthermore, if the foot is diagnosed with compartment syndrome, dorsomedial dermatofasciotomy should also be performed through upper and lower extensor retinacula.  This approach will also allow for open reduction and fixation.  Some cases may require medial malleolar osteotomy for anatomic reduction depending on the medial location and extension of the fracture. Patients with severe soft tissue damage and fracture-dislocations may have tibia-metatarsal external fixators applied and the necessary follow-up [25]. In the present case, it was decided to perform immediate open surgical reduction due to failure in the initial closed reduction and reduction was obtained by retrieving the talar head from the point where it was interlocked like a button and a buttonhole in the capsule by employing an anterolateral incision which could facilitate reduction. Open reduction approaches which have been suggested for anatomic reduction includes posteromedial, medial and anteromedial approaches.  Some authors have also reported the use of an anteromedial and anterolateral double incision [21]. These approaches provide various advantages. As an example, a posterolateral incision is known to disrupt the blood flow to a lesser extent, but makes it difficult to position the patient and offers a limited approach. Whereas a medial incision provides a more convenient approach specifically together with medial malleolar osteotomy, as there are known problems associated with osteotomy, in addition to the risks to the regional anatomic structures. Similarly, an anterolateral incision also has its own specific advantages and disadvantages. In general, the type of fracture and the experience level of the surgeon are considered to be more important for the approach to be selected [21]. Another important preference is the method of arthroscopic assisted internal fixation method, which has been defined in literature as a less invasive option specifically for the talar transchondral dome [21, 27].

Fixation with headless or bioabsorbable screws is recommended due to the anatomical structure of the talar bone and the articular nature of the major part of the surface.  In the current case, fracture fixation was secured with cannulated screws.  In cases where the fracture is accompanied by unstable joints and loss of reduction even after a small-scale strain, additional support may be provided to improve stability through the fixation of both subtalar and talonavicular joints with K-wires as in the current case. Consequently, talar body fractures involving distinct displacement pose a difficulty in treatment especially if they are accompanied by dislocation in an adjacent joint and long-term results are generally poor unless a good course of surgical treatment is followed.  Talectomy is not always practical because of problems such as pain on weight-bearing and instability, and should only be considered for adults. In this case, better results could be obtained when calcaneotibial fusion and talectomy are implemented concurrently [34].  Nevertheless, this should be included in the treatment as a final step.

Surgical complications pertaining to talus fractures notably include avascular necrosis [AVN], post-traumatic osteoarthritis, non-union, malunion, and infection. In a study of 26 cases of talar body fractures, poorest results were reported based on 1-year follow-up radiographs with AVN in 38%, with post-traumatic tibiotalar osteoarthritis in 65%, with post-traumatic subtalar osteoarthritis in 34%, and with segmental and severely displaced fractures [28]. Particularly after talar neck and body fractures, the AVN risk remains almost the same, while the risk of post-traumatic subtalar arthrosis is higher. Moreover, one study in literature reported the incidence of AVN for talar body fractures without dislocations to be 25% and the risk of AVN accompanying dislocation to be 50% [29]. Another meta-analysis indicated these rates as 10% without dislocation and 25% with dislocation [30]. The previously higher incidence of AVN has been reduced due to improved surgical approach methods that have been implemented in more recent literature [31, 32]. It has also been demonstrated that the waiting period for internal fixation does not create a significant effect in terms of the development of AVN in studies undertaken at various centres [32, 33]. Another study reported post-traumatic osteoarthritis at 50% in the ankle after compression fractures, at 41% after shear fractures and at 24% in the subtalar joint [11]. The incidence of osteoarthritis in talar body fractures is closely associated with the type of fracture and injury.  

Consequently, it is as difficult to diagnose talar body fractures as it is to apply treatment and to follow up the results of treatment. Even though extremely poor results have been reported for the treatment of such fractures in the past, much better results can be observed through accurate and meticulous surgical interventions in place today.  A study in literature reporting the results of talus fractures after a period of 30 months stated poorer AOFAS results for body fractures with an average score of 58 when compared to neck fractures with an average score of 79 and process fractures with an average score of 85.  The same study also noted the worse Maryland foot scores and Hawkins evaluation criteria for body fractures [ 2].  Another reference defined the average score in AOFAS as 68.4. [35]. The high value and successful AOFAS result obtained in the current case after a 2 year follow-up period can be considered to be due to the accurate interpretation of the fracture-dislocation,  anatomic reduction with early surgery, and good fixation.  However, there is still a need in literature for long-term results pertaining to such uncommon cases.

References

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  22. Azarkane M, Boussakri H, Alayyoubi A, Bachiri M, Elibrahimi A, Elmrini A. Closed medial total subtalar joint dislocation without ankle fracture: a case report. J Med Case Rep. 2014 Sep 20;8:313.7 http://www.ncbi.nlm.nih.gov/pubmed/25240955
  23. Wang KCTu YKFang CMLiu HTUeng SW. Talar body fracture combined with traumatic rupture of anterior talofibular ligament and peroneal longus tendon.                                                Chang Gung Med J. 2004;1;27 :56-60. http://www.ncbi.nlm.nih.gov/pubmed/15074891
  24. Sakaki MH, Saito GH, de Oliveira RG, et al. Epidemiological study on talus fractures. Rev Bras Ortop. 2014;8 5;49 (4):334-339. http://www.ncbi.nlm.nih.gov/pubmed/26229823
  25. Rammelt S, Zwipp H. Talar neck and body fractures. Injury 2009;40:120-135. http://www.ncbi.nlm.nih.gov/pubmed/18439608
  26. Nyska M, Howard CB, Matan Y, et al. Fracture of the posterior body of the talus- the hidden fracture. Arch Orthop Trauma Surg 1998;117:114-117. http://www.ncbi.nlm.nih.gov/pubmed/9457355
  27. Subairy ASubramanian KGeary NP.Arthroscopically assisted internal fixation of a talus body fracture. Injury. 2004;1;35 :86-89. http://www.ncbi.nlm.nih.gov/pubmed/14728962
  28. Vallier HA, Nork SE, Benirschke SK, Sangeorzan BJ. Surgical treatment of talar body fractures. J Bone Joint Surg [Am] 2003;85:1716-1724. http://www.ncbi.nlm.nih.gov/pubmed/12954830
  29. Adelaar RS. The treatment of complex fractures of the talus. Orthop. Clin. North Am 1989;4; 20 :691-707. http://www.ncbi.nlm.nih.gov/pubmed/2797758
  30. Kuner, E.H., Lindenmaier, H.L., and Munst, P.: Talus fractures. In Tscherne, H., and Schatzker, J. (eds.), Major Fractures of the Pilon, the Talus, and the Calcaneus: Current Concepts of Treatment. Berlin, Springer-Verlag, 1993: 71-85.
  31. Frawley PA, Hart JA, Young DA. Treatment outcome of major fractures of the talus. Foot Ankle Int 1995;16:339-345. http://www.ncbi.nlm.nih.gov/pubmed/7550941
  32. Schulze W, Richter J, Russe O, Ingelfinger P, Muhr G. Surgical treatment of talus fractures: a retrospective study of 80 cases followed for 1-15 years. Acta Orthop Scand 2002;73:344-351. http://www.ncbi.nlm.nih.gov/pubmed/12143985
  33. Lindvall E, Haidukewych G, DiPasquale T, Herscovici D Jr, Sanders R. Open reduction and stable fixation of isolated, displaced talar neck and body fractures. J Bone Joint Surg [Am] 2004;86: 2229-2234. http://www.ncbi.nlm.nih.gov/pubmed/15466732
  34. Adelaar RS. Complex fractures of the talus. Instr Course Lect 1997;46:323-338. http://www.ncbi.nlm.nih.gov/pubmed/9143977
  35. Ebraheim NAPatil VOwens CKandimalla Y. Clinical outcome of fractures of the talar body. Int Orthop. 2008 ;12;32 :773-777. http://www.ncbi.nlm.nih.gov/pubmed/17583811

Medial Subtalar Dislocation of the Foot Associated with an Acute Compartment Syndrome: A Case Report

by Muzamil Ahmad Baba1, M. A Halwai2, B.A Mir3, Adil Bashir4, Mubashir Wani5pdflrg

The Foot and Ankle Online Journal 6 (6): 1

Subtalar dislocation an uncommon injury, accounts for approximately 1% to 2% of all joint dislocations. Subtalar dislocation, also known as peritalar dislocation, refers to the simultaneous dislocation of the distal articulations of the talus at the talocalcaneal and talonavicular joints. This case report presents a rare situation of a medial subtalar dislocation complicated by an acute compartment syndrome that required an urgent fasciotomy which has never been reported before.

Key words: Subtalar dislocation, Compartment syndrome, Closed reduction, Fasciotomy.

Accepted: May, 2013
Published: June, 2013

ISSN 1941-6806
doi: 10.3827/faoj.2013.0606.001


Address correspondence to: Dr. Muzamil Ahmad Baba, Govt. Hospital for Bone and Joint Surgery Barzullah, Srinagar India, 190005. Mobile 9086181281. muzamilbaba79@yahoo.com.

1Orthopaedic Resident, Govt. Hospital for Bone and joint surgery Srinagar.
2Proffessor and Head Orthopaedics, Govt. Hospital for Bone and joint surgery Srinagar. drmahalwai@rediffmail.com


The subtalar dislocation occurs through the disruption of 2 separate bony articulations, the talonavicular and talocalcaneal joints.[1,2] These joints act as a hinge that transmits load and movement from the foot to the ankle. Subtalar dislocation is an uncommon injury that disturbs the normal anatomy and function of these joints. The medial dislocation, also known as an acquired clubfoot, is the most common of all subtalar dislocations, comprising approximately 80% to 85% of the cases.[3] The medial dislocation occurs through forceful inversion of the forefoot with the talar neck pivoting on the sustentaculum tali, which acts as a fulcrum to lever the calcaneus from the talus.

Initially, it is believed that the talonavicular joint is the first to dislocate, followed by rotary subluxation through the subtalar joint, with the talar head finally coming to rest between the extensor hallucis longus and the extensor digitorum longus on either the cuboid or navicular.[4] We present a rare case report of a 36-year-old male with a medial subtalar dislocation that was complicated by an acute compartment syndrome of the foot.

Case Report

A 36-year-old male presented to our hospital 12 hours after sustaining trauma to his right foot due to a twisting injury in his farm when he was carrying a heavy load over his right shoulder. He also gave a history of some manipulation by a quack, which did not give him any relief, but the intensity of pain increased following manipulation.

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Figure 1 The anteroposterior and Lateral radiograph of right foot showing a medial subtalar dislocation.

On examination, the patient was fully conscious and local examination revealed a deformity of the right foot with a prominence medially with tense swelling of the foot. Immediate radiographs in the emergency revealed a medial subtalar dislocation. (Fig.1) The dislocation was reduced in the emergency without anesthesia with gentle longitudinal and lateral traction of the foot, resulting in anatomic reduction of the talocalcaneal and talonavicular joints. (Fig.2) A posterior splint was applied and the limb was kept elevated and patient was observed every 15 minutes for two hours. The patient continued with pain, marked swelling encompassed the entire foot, with relative sparing of the digits. Sensation to pin prick was present to all the toes and web spaces, but two point discrimination was diminished. Pain on passive motion of the toes was present. The medial-plantar aspect of the foot (medial compartment) was particularly tense and swollen.

Severe bruising of the foot was evident. Further, there was pitting edema on the dorsum of the foot. (Fig.3 and 4) The toes were slightly pale and capillary refill was approximately 3 seconds on right and < less than 2 seconds on left foot. Sensory examination revealed continued paresthesia in the same distribution. After clinical examination, a decision for a fasciotomy was made. Intra-operatively tense compartment was confirmed and bulging muscle was noted in the medial incision.

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Figure 2 Immediate Post reduction anteroposterior and lateral radiograph of same patient.

Immediately postoperatively, the foot was placed in a well-padded splint, elevated, and intravenous antibiotics administered (cefazolin). Five days later, the fasciotomy wounds were closed. The patient was discharged on the day following fasciotomy closure. Follow-up at 2 years revealed well-healed incisions, absence of neuromuscular deficits with excellent functional recovery with no signs of AVN of the talus.

Discussion

Subtalar dislocations are rare, accounting for only 1% to 2% of all dislocations.[1] Smith noted only seven dislocations in a review of 535 dislocations of all types.[5] Leitner noted only 42 among 4215 dislocations.[6] Although first described in 1811 by Judcy and Dufaurets, it involves the disruption of the talocalcaneal and talonavicular joints, while the calcaneocuboid joint remains intact.[6]

STDisFig3 STDisFig4
Figure 3 and 4 Clinical photographs of patient showing tense foot compartment prior to fasciotomy.

Subtalar dislocation can occur in any direction. Significant deformity is always present. Up to 85% of dislocations are medial.[3] The calcaneus, with the rest of the foot is displaced medially while the talar head is prominent in the dorsolateral aspect of the foot. The navicular is medial and sometimes dorsal to the talar head and neck. Lateral dislocation occurs less often. In a lateral dislocation, the calcaneus is displaced lateral to the talus and the talar head is prominent medially. The navicular lies lateral to the talar neck. Rarely, a subtalar dislocation is reported to occur in a direct anterior or posterior direction, but these are usually associated with medial or lateral displacement as well. The direction of subtalar dislocation has important effects with respect to management and outcome. The method of reduction is different for each type of injury.

Radiographs of a subtalar dislocation may be difficult to interpret. The severity of the deformity makes it difficult to obtain true anteroposterior and lateral images of the foot, and standard ankle radiographs do not reveal the foot pathology.[7]

It is important to note that the relationship between the talus and tibia and fibula is normal in a peritalar dislocation because the point of injury is distal to the ankle joint. The anteroposterior view of the foot demonstrates the talonavicular dislocation. Usually interpretation of the plain radiographs provides enough information to determine the direction of the dislocation, such that the physician can proceed with an attempt at reduction.

All subtalar dislocations require a gentle and timely reduction. In most cases, reduction can be accomplished closed. Often the injury presents with skin tenting such that a prompt reduction will reduce the possibility of skin necrosis. Once the reduction is accomplished, it should be confirmed by clinical examination and radiographs. The outcome following simple dislocations treated with closed reduction seems to be favorable.[8] In some series, as few as 10% of patients with medial dislocations and 15% to 20% of lateral subtalar dislocations required open reduction.[6] Recent series, particularly from trauma centers, have noted the need for open reduction to be more common, with 32% of patients requiring open reduction in one series.[9] A variety of bone and soft tissue structures may become entrapped, resulting in a block to closed reduction. These impediments require open manipulation or release to facilitate reduction.

Subtalar dislocations have a wide variance in terms of their prognosis. Uncomplicated subtalar dislocations, stable following a closed reduction, have an excellent prognosis with minimal symptoms at long-term follow-up.[8] Certain subtalar dislocations are clearly associated with a worse prognosis. Lancaster, et al., in a review of the literature, noted that associated injuries and complications were associated with a worse result. In particular, soft tissue injury, extra-articular fracture, intra-articular fracture, and osteonecrosis were associated with a worse outcome.[10] Open fractures are undoubtedly associated with the poorest results. Goldner et al., reviewed 15 patients at a mean of 18 years following open subtalar dislocations. Associated injuries were noted to the tibial nerve in 10 patients; to the posterior tibial tendon in 5; and to the posterior tibial artery in 5. Seven patients ultimately required arthrodesis due to osteonecrosis or post traumatic arthritis.[11]

Osteonecrosis of the talus may develop following peritalar dislocations. Overall, osteonecrosis is uncommon and generally only noted with high-energy and open injuries. Theoretically, the talus is not displaced from the ankle mortise and therefore at least some of the blood supply should be preserved. However, Goldner, et al., noted osteonecrosis in 5 of 15 patients with grade 3 open subtalar dislocations.[11] In addition, Bibbo, et al., also observed osteonecrosis in three patients.[9] Although our case was complicated by development of a compartment syndrome but timely intervention resulted in an excellent result in our case.

Conclusion

The majority of subtalar dislocations can be treated in a closed manner with a period of nonweight bearing and immobilization with satisfactory results. Occasionally, these patients may develop a compartment syndrome which, if not treated in time, may lead to catastrophic results. A high clinical suspicion and observation is warranted especially in cases with delayed presentation to diagnose such a condition early and manage it in a timely manner.

References

1. Perugia D, Basile A, Massoni C, Gumina S, Rossi F, Ferretti A. Conservative treatment of subtalar dislocations. Int Orthop 2002 26: 56-60. [PubMed]
2. Barber JR, Bricker JD, Haliburton RA. Peritalar dislocation of the foot. Can J Surg 1961 4: 205-210. [PubMed]
3. Monson ST, Ryan JR. Subtalar dislocation. JBJS 1981 63A: 1156-1158. [PubMed]
4. Buckingham WW Jr, LeFlore I. Subtalar dislocation of the foot. J Trauma 1973 13: 753-765. [PubMed]
5. Smith H. Subastragalar dislocation: a report of seven cases. JBJS 1937 19B: 373-380.[Website]
6.  Leitner B. Obstacles to reduction in subtalar dislocations. JBJS 1954 36A: 299-306. [PubMed]
7. Gross RH. Medial peritalar dislocation, associated foot injuries and mechanism of injury. J Trauma 1975 15: 682-688.[PubMed]
8. Delee JC, Curtis R. Subtalar dislocation of the foot. JBJS 1982 64A: 433-437. [PubMed]
9. Bibbo C, Anderson RB, Davis WH. Injury characteristics and the clinical outcome of subtalar dislocations: a clinical and radiographic analysis of 25 cases. Foot Ankle Int 2003 24:158-163. [PubMed]
10. Lancaster S, Horowitz M, Alonso J. Subtalar dislocations: a prognosticating classification. Orthopedics 1985 8:1234-1240. [PubMed]
11. Goldner JL, Poletti SC, Gates HS 3rd, et al. Severe open subtalar dislocations. Long-term results. JBJS 1995 77A: 1075-1079. [PubMed]

Lateral Subtalar Dislocation of the Foot: A case report

by Dr. M.R.Jayaprakash 1, Dr.Vijaykumar Kulumbi 2, Dr.Ashok Sampagar 3, Dr.Chetan Umarani 4

The Foot and Ankle Online Journal 4 (11): 1

Subtalar dislocation, also known as peritalar dislocation, refers to the simultaneous dislocation of the distal articulations of the talus at the talocalcaneal and talonavicular joints. Subtalar dislocation can occur medially or laterally with resulting deformity. Medial dislocations comprise up to 85% of subtalar dislocations whilst lateral subtalar dislocations are less frequent and in 15% to 20% of dislocations. Closed reduction and immobilization remains the treatment of choice. The tibialis posterior, talar head impaction, and entrapment of the joint capsule may cause difficulty in closed reduction of lateral dislocations; hence open reduction may be necessary. This case report presents an unsuccessful closed reduction of a lateral subtalar dislocation which required an open reduction technique using wire stabilization.

Key words: Subtalar dislocation, talus, trauma, closed reduction, open reduction.

Accepted: October, 2011
Published: November, 2011

ISSN 1941-6806
doi: 10.3827/faoj.2011.0411.0001


Subtalar dislocation is a rare rearfoot injury, it disturbs the normal anatomy and function between the talus, calcaneus and navicular bone. [1,2,3,7,10] The talocal-caneal and talonavicular joints can be dislocated simultane¬ously, without a fracture of the neck of the talus .This has also been referred to as a peritalar or subastragalar dislocation. [4]

Although some dislocations may completely reduce or even partially reduce on its own, there are basically two types of subtalar dislocation reported in the literature. In lateral subtalar dislocation, the head of talus is found medially and the rest of the foot is dislocated laterally. In medial subtalar dislocation, the head of the talus is found laterally and the rest of the foot is dislocated medially. [4,6]

However, in a lateral subtalar dislocation, the talus can remain fixed while the remaining structures of the foot are dislocated laterally along the talus. It is important to check the stability and congruity of the talus in the ankle mortise with any subtalar dislocation.

Subtalar dislocations present with an impressive amount of deformity. Medial dislocation has been referred to as an “acquired clubfoot”, while the lateral injury is described as an “acquired flatfoot”. [6,7] Lateral dislocations are particularly prone to poor results, due to the frequency of open injuries and associated fractures4. We report a case of lateral subtalar dislocation in 35 year-old man in whom closed reduction was unsuccessful hence open reduction was performed.

Case Report

A 35 year-old man, who sustained a high energy trauma while travelling on a two-wheeler. He was then hit by an oncoming tractor. He presented to Bapuji Hospital. The foot was diffusely swollen with a laceration over the medial border of the foot. The skin was distorted and markedly tented over the prominent head of the talus which was felt medially. The posterior tibial artery was not palpable due to severe swelling and the dorsalis pedis artery was palpable. Radiographs showed that the foot along with calcaneum had moved laterally off the talus. (Figs. 1A, 1B and 1C)

  

Figures 1A, 1B and 1C Radiographs showing talonavicular dislocation. (A and B).  Initial radiograph showing lateral subtalar dislocation without signs of fracture.  The talus is displaced along the ankle mortise. (C)

Initially a closed reduction was attempted and this was unsuccessful. The patient was then prepared for surgery for open reduction and stabilization. A medial incision was performed extending the lacerated wound. The posterior tibial tendon was identified. The displaced talus was relocated into the joint after further dissection and reduction. The posterior tibial tendon was retracted and the talus was levered into the position and reduction was achieved. Reduction was confirmed using a computer assisted radio monitor (c- arm). (Fig. 2A and 2B) A thick Kirschner wire was inserted from the calcaneum into the talus to hold the reduction. A below knee splint was applied after placing sterile dressing on the operative site. The splint was then replaced with a windowed cast to inspect the incision daily.The operative reduction was successful. (Fig. 3A and 3B)

 

Figures 2A and 2B  Intraoperative radiographic scans showing insertion of Kirschner wire through the calcaneum.

 

Figures 3A and 3B Intraoperative photographs showing correction of deformity after the reduction of dislocation.

Discussion

Dislocation of the talus can occur in conjunction with major talus fractures. [5] However, dislocations can also occur with no associated bony injury or with relatively minimal appearing fractures. [3,4] Subtalar dislocation, also known as peritalar dislocation refers to the simultaneous dislocation of the distal articulations of the talus at the talocalcaneal and talonavicular joints. [4,6]

First described by Judcy and Dufaurets [7] in 1811, clinical reviews of subtalar dislocations are relatively infrequent and generally limited to small numbers of patients. Subtalar dislocation can occur in any direction. Significant deformity is always present. Up to 85% of dislocations are medial. [5,7] The calcaneus, with the rest of the foot is displaced medially while the talar head is prominent in the dorsolateral aspect of the foot. The navicular is medial and sometimes dorsal to the talar head and neck. Lateral dislocation occurs less often about 10-15%. [6,7,10]

In a lateral peritalar dislocation, the calcaneus and navicular is displaced lateral to the talus and the talar head is prominent medially. [4,10] Rarely, a subtalar dislocation is reported to occur in a direct anterior or posterior direction, [2,7] but these are usually associated with medial or lateral displacement as well.

Between 10% and 40% of subtalar dislocations are open. [13] 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 dislocations. [13]

The majority of subtalar dislocations can be reduced in a closed manner in the emergency department with the use of local anesthesia and procedural sedation. Early reduction is essential to prevent loss of skin due to pressure necrosis from the underlying dislocation. [4]
In approximately 10% of medial subtalar dislocations and 15% to 20% of lateral dislocations, closed reduction cannot be achieved. [11,12] Soft tissue interposition and bony blocks have been identified as factors preventing closed reduction. [11] With medial dislocations, the talar head can become trapped by the capsule of the talonavicular joint, the extensor retinaculum or the extensor tendons, or the extensor digitorum brevis muscle. [11,12] With a lateral dislocation, the posterior tibial tendon may become when firmly entrapped and present as a barrier to closed and even open reduction. [7,12]

In 1954, Leitner [12] initially proposed a mechanism by which the flexor retinaculum is disrupted, allowing the tendon to drape over the talar head and preventing reduction. In 1982 DeLee, et al., [4] in their case series three of the four lateral disloca¬tions required open reduction. Of these three, the posterior tibial tendon was the obstructing agent in two and a fracture of the head of the talus prevented closed reduction in one.

In our case presentation, the patient had sustained high energy trauma. Initially a closed reduction was attempted, but was unsuccessful. In the open reduction, we identified the tibialis posterior tendon as obstructing the reduction. Open reduction with Kirschner wire or Steinman pin reduction is shown to successfully reduce a lateral subtalar dislocation in this case report.

References

1.Brunet P, Dubrana F, Burgand A, Nen De Le, Lefebre C. Subtalar dislocation: review of ten cases at mean ten-year follow-up. JBJS 2004 86B (Supp 1):57.
2. Lyrtzis CH, Papadopoulos A, Fotiadis E, Ntovas TH, Petridis P, Koimtzis M. Isolated medial subtalar dislocations -conservative treatment. EEXOT 2009: 195-198
3 Capelli RM, Galamnini V, Crespi L. Subtalar anterolateral dislocations: case report and literature review. J Orthop Traumatol 2002 3:181-183.
4. DeLee JC, Curtis R .Subtalar dislocations of the foot. JBJS 1982 64A: 433-437.
5. Monson ST, Ryan JR. Subtalar dislocation. JBJS 1981 63A: 1156-1158,
6. J. Terrence Jose Jerome, Mathew Varghese, Balu Sankaran, K. Thirumagal. Lateral subtalar dislocation of the foot: A case report. The Foot & Ankle Journal, 2008 1 (12): 2.
7. Sanders DW. Fractures of the talus. In: Bucholz RW, Heckman JD, Court-Brown C, eds. Rockwood and Green’s Fractures in Adults. Vol 1. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2249-2292, 2006.
8. Plewes LW, McKelvey KG. Subtalar dislocation. JBJS 1944 26A: 585-588.
9. Smith H. Subastragalar dislocation: a report of seven cases. JBJS 1937 19A: 373-380
10. Joel Horning,John DiPreta .Subtalar Dislocation. Orthopedics 2009; 32:904
11. Mulroy, R. D.: The tibialis posterior tendon as an obstacle to reduction of a lateral anterior subtalar dislocation. JBJS 1955 37A: 859-863.
12. Leitner, L., Baldo: Obstacles to reduction in subtalar dislocations. JBJS 1954 36A: 299-306.
13. Goldner JL, Poletti SC, Gates HS 3rd, Richardson WJ. Severe open subtalar dislocations: long-term results. JBJS 1995 77A: 1075 -1079


Address correspondence to: Dr.M.R.Jayaprakash Ramakrishna, 43, PJ extension, 2nd main, 7th cross, Davanagere, Karnataka India 577002 . Phone (Mobile) – +919448667305, (Clinic) – 08192-253609, Email- umaranicm@gmail.com, ashok.samp@gmail.com

1  Professor and Unit Head,Department of Orthopaedics, JJM Medical College,Davangere, India 577004.
2  Professor of Department of Orthopaedics. JJM Medical College, Davangere, India 577004.
3  Resident in Orthopaedics. JJM Medical College. Davangere, India 577004.
4  Resident in Orthopaedics. JJM Medical College. Davangere, India 577004.

© The Foot and Ankle Online Journal, 2011

Peritalar Dislocation: A Case Report and Literature Review

by Dr. Oliver Blocker MRCS1 , Dr. Jacqui Orme MBBS2 , Dr. Anirudh Gadgil FRCS (Ortho)3  

The Foot and Ankle Online Journal 2 (11): 3

A case of closed medial peritalar dislocation is presented. Immediate closed reduction and conservative management of associated fractures followed by early physiotherapy led to an excellent outcome of this potentially devastating injury. A review of the literature on this rare injury is also discussed.

Key Words: Peritalar dislocation, subtalar dislocation.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License.  It permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ©The Foot and Ankle Online Journal (www.faoj.org)

Accepted: October, 2009
Published: November, 2009

ISSN 1941-6806
doi: 10.3827/faoj.2009.0211.0003


Case Report

A seventy four year-old male patient presented with severe pain and the inability to bear weight after sustaining an inversion injury to the right ankle following a three feet fall from a ladder. This was a closed injury without neurovascular compromise. The ankle and rearfoot were deformed. (Fig.1)

Figure 1  Clinical photograph showing a medially dislocated rearfoot.

Plain radiographs showed the dislocation of the talonavicular and subtalar joints, with the navicular and calcaneus displaced medially. (Figs. 2 and 3) A lateral view also showed an avulsion fracture of the posterior process of the talus. A closed reduction was performed under general anesthesia using image intensifier guidance.

Figure 2  Antero-posterior radiograph demonstrating intact tibio-talar articulation and the disarticulation between the head of the talus and the navicular, with the navicular and calcaneum being displaced medially.

Figure 3  Lateral view radiograph of the ankle and foot.  Avulsion fractures of the posterior process of the talus and anterior process of the calcaneum are seen.  The dislocated talonavicular joint is seen.  Incongruity of the subtalar articulation gives an indication to the subtalar dislocation.

A post-operative computed tomography (CT) scan confirmed anatomical reduction of subtalar and talonavicular joints and also demonstrated a vertical posterior process fracture of the talus extending to the subtalar joint as well as a fracture of the anterior process of the calcaneus extending into the calcaneocuboid joint. (Fig. 4)

Figure 4 Three dimensional (3D) reconstruction of the post reduction CT scan shows a vertical fracture of the posterior process of the talus and a well-reduced subtalar joint.

These were in an acceptable anatomical position and no further surgical intervention was undertaken. The patient was treated in a plaster of Paris, below knee, non-weight bearing cast for a period of 6 weeks and was then allowed to weight bear. Physiotherapy in the form of active and passive mobilization of the ankle, rearfoot and midfoot joints began at 6 weeks. Radiographs revealed the fracture had united at three months follow up and the patient was pain free in his daily activities involving weight bearing. (Fig. 5)

Figure 5  Radiographs taken at the 3-month follow-up show complete bony resolution of the injury with good talonavicular and subtalar joint position.

Discussion

Peritalar dislocation refers to the injury involving the simultaneous dislocation of both the talocalcaneal and talonavicular joints without a fracture of the talar neck or tibiotalar joint disruption. [1] It is rare and considered to be a severe injury as it involves the weight bearing articular surfaces of the subtalar joints. [2,3]

There are two types of normal movements that occur at the talocalcaneal and talonavicular joint. These have been described as ‘triplanar’ movements. [4] They are inversion, plantarflexion and adduction as one movement and eversion, dorsiflexion and abduction as the other. This gives the peritalar joint the potential for a variety of dislocations. A medial dislocation is the most common although dislocations can occur laterally, anteriorly and posteriorly. [1,5,6,7] Peritalar dislocation is usually the result of high-energy trauma or sporting injuries and accounts for 1% of all dislocations. [1,8]

Although open reduction and internal fixation of talar fractures is an option,9 the literature suggests that closed reduction is the most common and appropriate method of treatment for medial dislocations. [1,3,4,6,10,11]

Regardless of the reduction method used, early reduction is the key to ensuring a good prognosis for recovery. [8,10] Peritalar dislocation is a potentially devastating injury [12] in which the complications range from chronic pain from subtalar arthrosis to talar avascular necrosis. [5,9,12] Avascular necrosis is rare from simple talar neck fractures as there are multiple vascular anastomoses within the bone itself. The blood supply to the talus is from multiple extra-osseal vessels that surround the bone. [13] The extensive soft tissue damage that occurs in peritalar dislocation disrupts these vascular arcades. If this is not corrected, avascular necrosis is likely to occur. Therefore early reduction gives the best chance of restoring the blood supply and minimizes the risk of avascular necrosis. Varying disability results from medial dislocations but early reduction and mobilization of the joint is associated with a better prognosis [7]; lateral and open fracture dislocations are associated with poorer outcomes. [6] Currently, the literature suggests a period of non-weight bearing of 4 weeks with no fracture and 6 weeks with an associated fracture. [6] Our management included active physiotherapy from the end of the non-weight bearing period until the 3-month follow up. We believe this contributed to the patient’s rapid recovery.

The figures included in this report should assist clinicians in the recognition of medial dislocations (Fig. 1), highlight the potential complications such as associated talar fractures (Figs. 3 and 4) and demonstrate the excellent outcomes that can be achieved with early reduction and active rehabilitation (Fig. 5).

In conclusion peritalar dislocations are rare injuries usually sustained by high-energy trauma and have the potential for serious complications such as avascular necrosis of the talus and subtalar arthrosis. However urgent treatment by anatomical reduction followed by early rehabilitation can provide a good outcome.

References

1. Harris J, Huffman L, Suk M: Lateral peritalar dislocation: a case report. Journal of Foot & Ankle Surgery 47 (1): 56 – 59. 2008.
2. Simon LC, Schulz AP, Faschingbauer M, Morlock M, Jurgens C: “Basketball Foot” – long-time prognosis after peritalar dislocation. Sportverletzung Sportschaden 22 (1): 31 – 37, 2008.
3. Biswas S, Murphy M. Subtalar dislocation. The Internet Journal of Orthopedic Surgery 2: 3, 2006. Accessed 1st March 2008.
4. Ledoux WR, Sangeorzan BJ: Clinical biomechanics of the peritalar joint. Foot & Ankle Clinics 9 (4): 663 – 683, 2004.
5. Wagner R, Blattert TR, Weckbach A. Talar dislocations. Injury 35 (Suppl 2): SB36 – 45, 2004.
6. Garofalo R, Moretti B, Ortolano V, Cariola P, Solarino G, Wettstein M, Mouhsine E: Peritalar dislocations: a retrospective study of 18 cases. Journal of Foot & Ankle Surgery 43(3): 166 – 172, 2004.
7. Merianos P, Papagiannakos K, Hatzis A, Tsafantakis E: Peritalar dislocation: a follow-up report of 21 cases. Injury 1988 19 (6): 439 – 442, 1988.
8. Maes R, Averous C, Copin G: Lateral peritalar luxation: prognostic evaluation and therapeutic approach. Review of the literature based on a clinical case. Revue Medicale de Bruxelles 24(6): 458 – 463, 2003.
9. Besch L, Drost J, Egbers HJ: Treatment of rare talus dislocation fractures. An analysis of 23 injuries. Unfallchirurg 105 (7): 595 – 601, 2002.
10. Horer DI, Fishman J: The early treatment of peritalar dislocation. International Orthopaedics 7 (4): 263 – 266, 1984.
11. Kumar P, Bajracharya S, Pandey S: Medial peritalar dislocation in a volleyball player. Journal of the Nepal Medical Association 45 (163): 314 – 325, 2006.
12. Marcinko DE, Zenker CC: Peritalar dislocation without fracture. Journal of Foot Surgery 30 (5): 489 – 493, 1991.
13. Mulfinger GL, Trueta J: The blood supply of the talus. Journal of Bone Joint Surgery 52B (1): 160 – 167, 1970.


Address correspondence to: West Wales General Hospital (WWGH), Dolgwili Road, Carmarthen, Dyfed, SA31 2AF, WALES.

Dr. Oliver Blocker MRCS – CT1 Trauma and Orthopaedics, WWGH, 3 Glyn Hirnant, Clydach Road, Morriston, Swansea, SA6 6QS, WALES.
Dr. Jacqui Orme MBBS – F2 Trauma and Orthopaedics, WWGH , 3 Glyn Hirnant, Clydach Road, Morriston, Swansea, SA6 6QS, WALES.
Dr. Anirudh Gadgil FRCS(Ortho) – Consultant Foot and Ankle Surgeon, WWGH, 3 Glyn Hirnant, Clydach Road, Morriston, Swansea, SA6 6QS, WALES.

© The Foot and Ankle Online Journal, 2009

Lateral Subtalar Dislocation of the Foot: A case report

by J. Terrence Jose Jerome, MBBS, DNB (Ortho), MNAMS (Ortho)1 , Mathew Varghese, M.S. (Ortho)2 , Balu Sankaran, FRCS, FAMS3 , K. Thirumagal, MD4

The Foot & Ankle Journal 1 (12): 2

Subtalar dislocation is the simultaneous dislocation of the distal articulations of the talus at both the talocalcaneal and talonavicular joints. It can occur in any direction and always produce significant deformity. Most common is the medial dislocation. Less common presentations are lateral, anterior and posterior dislocations. These dislocations are associated with osteochondral fractures. Closed reduction and immobilization remains the mainstay of treatment. Radiographs and computed tomography scan confirms the post reduction alignment stability of subtalar joints and intra-articular fracture fragments. We report a case of lateral subtalar dislocation without osteochondral fracture fragments in a 30-year-old man.

Key words: Subtalar dislocation, dislocated talus, closed reduction, immobilization

This is an Open Access article distributed under the terms of the Creative Commons Attribution License.  It permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ©The Foot & Ankle Journal (www.faoj.org)

Accepted: November, 2008
Published: December, 2008

ISSN 1941-6806
doi: 10.3827/faoj.2008.0112.0002

Subtalar dislocations are rarely found in routine orthopedic practice. Many of these dislocations result from high-energy injuries such as falls from a height, athletic injuries or a motor vehicle accident. [1] Inversion or eversion force is dissipated through the weak talonavicular and talocalcaneal ligaments, which eventually result in subtalar dislocation.

There are two types of subtalar dislocation. In lateral subtalar dislocation, the head of talus is found medially and the rest of the foot is dislocated laterally. In medial subtalar dislocation, the head of the talus is found laterally and the rest of the foot is dislocated medially.

Medial dislocation has been referred to as an “acquired clubfoot”, while the lateral injury is described as an “acquired flatfoot”. We present a case of an adult with lateral subtalar dislocation following a fall.

Case Report

A 30-year-old man who sustained a fall from the stairs came to our emergency department with pain and swelling of the right foot. The foot was diffusely swollen with minimal laceration and tenting of the skin over the prominent talar head which was felt medially. The rest of the foot was found dislocated laterally. (Figs. 1 and 2) Pulse of the posterior tibial and dorsalis pedis artery were not felt due to massive soft tissue distortion. Radiograph of the right foot showed lateral subtalar dislocation. (Figs. 3 and 4) Doppler ultrasound showed normal arterial flow in both posterior tibial and dorsal pedis arteries.

Figure 1   The foot was diffusely swollen with minimal laceration and tenting of the skin over the prominent talar head which was felt medially.

Figure 2   The right foot was found to be dislocated laterally.

Figure 3   The dorsoplantar view shows the dislocation of the talo-navicular and subtalar joints. Head of the talus was seen lying medially. Normal alignment of calcaneo-cuboid joint is appreciated.

Figure 4   The lateral view again shows the dislocation of the talo-navicular and subtalar joints. Head of the talus is severely declinated.

Closed reduction was done under spinal anesthesia. Firm manual foot traction with counter-traction on the leg combined with direct digital pressure over the head of talus aided in smooth reduction, which was associated with an audible clunk.

Post reduction radiographs showed normal and stable alignment of subtalar and talo-navicular joints without osteochondral fractures. (Figs. 5 and 6)

Figure 5   The post reduction anterior posterior radiograph showed normal and stable alignment of subtalar and talo-navicular joints without osteochondral fractures.

Figure 6   The post reduction lateral radiograph showed normal and stable alignment of subtalar and talo-navicular joints without osteochondral fractures.

Computer tomography (CT) scan confirmed the absence of osteochondral fractures and the stability of the subtalar joints. The patient was immobilized in a short-leg posterior plaster splint for 4 weeks. Following immobilization, the patient underwent a vigorous, active exercise program. The patient progressed to weight bearing and active range of motion exercises to regain subtalar and midtarsal joint motion. Two years after the injury, the patient had a stable, relatively good functional foot with minimal pain on walking on uneven ground.

Discussion

Subtalar dislocation by definition has a normal tibiotalar joint. Most dislocations occur in males (6:1) of early age. Subtalar dislocation can occur in any direction and always produce significant deformity.

Most commonly (80% to 85%), the foot is displaced medially with the calcaneus lying medially, the head of the talus prominent dorsolaterally, and the navicular medial and sometimes dorsal to the talar head and neck. [1,2,3] Less commonly (15% to 20%), lateral dislocation occurs.

Inversion of the foot results in a medial subtalar dislocation, while eversion produces a lateral dislocation. The strong calcaneonavicular ligament resists disruption, and the inversion or eversion force is dissipated through the weaker taloavicular and talocalcaneal ligaments. This disrupts these two joints which causes displacement of the calcaneus, navicular and all distal bones of the foot as a unit, either medially or laterally. [2,3]

The sustentaculum tali acts as a fulcrum about which the foot rotates to lever apart the talus and calcaneus in medial subtalar dislocation. The foot pivots about the anterior process of the calcaneus, again causing the talus and calcaneus to separate in lateral subtalar dislocation. [1,2,3,4]

Rare cases of anterior [5] and posterior [1] displacement of the foot after subtalar dislocation have also been reported. It is important to distinguish the medial or lateral subtalar dislocations because the method of reduction is different and the long-term prognosis appears to be worse with the lateral dislocation.

Between 10% and 40% of subtalar dislocations are open.6 Open injuries tend to occur more commonly with the lateral subtalar dislocation pattern and probably as the result of a more violent injury. [6] Long term follow-up demonstrated very poor results with the open subtalar dislocations.

The keystone of treatment for all subtalar dislocations is prompt and gentle reduction under general or spinal anesthesia. [7] All open injuries must be thoroughly debrided at the time of reduction, and the wound should be left open, with delayed primary closure anticipated in 3 to 5 days. Due to the high incidence of associated articular fracture and associate poor prognosis, CT scan of the foot and ankle should be obtained after reduction and splinting.

Simple dislocation that is reduced readily by closed reduction and do not have associated fracture, do very well. [1] In approximately 10% of medial subtalar dislocations and 15% to 20% of lateral dislocations, closed reduction cannot be achieved. [3,8] Soft tissue interposition and bony blocks have been identified as factors preventing closed reduction. Another common obstruction to closed reduction in medial dislocations is an impaction fracture of the articular surface of talus and navicluar. [7]

In comparison, the most common obstruction to closed reduction in lateral subtalar dislocation is the interposed tibialis posterior tendon. [8]

Open reduction is done for irreducible medial, lateral subtalar dislocations and osteochondral fracture fragments which blocks closed reduction. Any small, loose articular fracture fragments should be removed. Large intra-articular fractures should be reduced and fixed with Kirschner wires or small screws to restore joint stability and congruity. [9]

The only consistent complication in simple uncomplicated dislocations is limitation of subtalar joint motion, with the occasional associated symptoms of difficulty in walking on uneven ground and pain in the foot with weather changes. [2,7]

Lancaster and co-workers noted a poorer prognosis when there were associated injuries such as soft tissue injury, open contaminated injuries, extra-articular fracture, intra-articular fracture, infections, lateral subtalar dislocations, neglected subtalar dislocations and osteonecrosis. [10]

Our patient, who had sustained a fall from stairs, came with a diffusely swollen foot with the head of talus felt medially and the rest of the foot dislocated laterally as a unit. Radiographs confirmed the lateral subtalar dislocation. There was no associated osteochondral fracture. Simple closed reduction was successful. Our literature review showed few reports of isolated lateral subtalar dislocation.

We emphasize the importance of proper diagnosis and timely management of dislocations around the subtalar joint, as these tend to result in a significant deformity with joint stiffness. Lateral subtalar dislocation is one such type dislocation which is not mentioned in the literature and should be carefully treated. There should always be a high index of suspicion concerning associated osteochondral fractures. CT scan should be performed after reduction to assess for the intra-articular fractures of the subtalar joint. Open reduction is recommended for irreducible dislocations and fixation is recommended in large displaced, articular fractures that can produce subtalar joint incongruity.

References

1. DeLee JC, Curtis R. Subtalar dislocation of the foot. J Bone Joint Surg 64A: 433 – 437, 1982.
2. Grantham SA. Medial Subtalar dislocation: five cases with a common etiology. J Trauma 4 (11): 845 – 849, 1964.
3. Heppenstall RB, Farahvar H, Balderston R, Lotke P. Evaluation and management of subtalar dislocations. J Trauma 20 (6): 494 – 497, 1980.
4. Monson ST, Ryan JR. Subtalar dislocation. J Bone Joint Surg 63A (7): 1156 – 1158, 1981.
5. Inokuchi S, Hashimoto T, Usami N. Anterior subtalar dislocation: case report. J Orthop Trauma 11(3): 235 – 237, 1997.
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Address correspondence to: Dr. J. Terrence Jose Jerome, MBBS.,DNB (Ortho), MNAMS (Ortho)
Registrar in Orthopedics, Dept. of Orthopedics
St. Stephen’s Hospital, Tiz Hazari, Delhi 54, India

1 Registrar in Orthopedics, Department of Orthopedics, St. Stephens Hospital, Tiz Hazari, Delhi, India.
2 Head Professor, Department of Orthopedics, St. Stephens Hospital, Tiz Hazari, Delhi, India.
3 Professor Emeritus, Orthopedics, St. Stephens Hospital, Tiz Hazari, Delhi, India. E-mail: pasle@bol.net.in
4 Professor , Orthopedics, Tamilu, India.

© The Foot & Ankle Journal, 2008