Introduction

Total talar dislocation (TTD) is a rare medical entity accounting for 0.06% of all dislocations and 2% of all talar injuries (1). A plantarflexed and inverted foot dislocates the talus from the tibiotalar, talocalcaneal and talonavicular joints. Often resulting from high energy trauma, TTD is often associated with open wounds and fractures of the talus, malleoli and other bones (2). Owing to its limited blood supply and significant associated injuries, complications such as talar avascular necrosis (AVN), osteoarthritis (OA) and infection are common (2, 3).

Closed isolated TTD, without any fracture, represents an even rarer entity (5). With even fewer reports in medical literature and no standardized treatment protocol, the treatment approach and long-term outcomes of closed isolated TTD are even more unclear. This case report presents an extremely rare case of closed isolated TTD, with significant ligamentous injuries, that was successfully treated with prompt closed reduction and achieved good outcomes without any significant complications such as AVN.

Case Report

A 29-year-old male fell from a recreational rock-climbing wall and sustained a left ankle sprain. He described the mechanism to be one of plantarflexion and inversion. This resulted in a painful swollen left ankle which he was unable to bear weight on.

The physical examination upon hospital admission revealed a medially shifted hindfoot, supinated forefoot and no open wounds. The distal neurovasculature was intact and the capillary refill was within 2 seconds.

Radiographs of the left foot and ankle demonstrated an anterolateral total dislocation of the talus with no associated fractures.

Figure 1

The patient received closed reduction in a ward treatment room under IV sedation (Fentanyl and Midazolam) with 2 clinicians and x-ray guidance. Closed reduction was performed in accordance with the method described by Mitchell (5). One clinician held the left leg with the knee flexed at 90 degrees whilst the other provided traction of the heel and forefoot. Two thumbs applied direct pressure on the anterolaterally dislocated talar mass which rotated it 90 degrees into its appropriate anatomical position. A clunk feeling was elicited upon successful reduction. The radiological alignment and stability were confirmed under x-ray. The post-procedure skin condition was satisfactory, distal neurovasculature was intact and the capillary refill was within 2 seconds. A short leg slab was applied to immobilize the ankle and foot. The time from injury to completion of closed reduction was approximately 6 hours.

Formal radiographs and computed tomography (CT) were taken after casting that further confirmed adequate reduction of the talus and no associated fractures. After observation of the satisfactory skin condition over 24 hours, a short leg cast was applied. Strict non-weight-bearing (NWB) walking was adhered to for 4 weeks.

Figure 2

Figure 3

Upon follow-up appointments serial radiographs confirmed the satisfactory alignment of the talus and no AVN changes. At 4 weeks post-injury the cast was removed and partial-weight-bearing (PWB) walking and physiotherapy was prescribed for a further 4 weeks. At 8 weeks post-injury the patient reported a relatively pain-free ankle with good mobility. The anterior drawer test did not demonstrate any laxity. The distal neurovasculature was intact and the capillary refill was within 2 seconds.

Magnetic resonance imaging (MRI) of the left foot and ankle at 3 months post-injury did not reveal any AVN changes or osteochondral lesions. There was complete tear of the anterior talofibular ligament (ATFL) and high-grade tears of the deep deltoid ligament (DL), calcaneofibular ligament (CFL) and posterior talofibular ligament (PTFL).

Figure 4

The patient resumed his duties as a construction labourer by 3 months post-injury. He reported good tolerance to these duties with only mild aches after prolonged standing.  Follow-up radiographs 3 years post-injury thus far have not shown any signs of AVN or OA.

Figure 5

Discussion

The talus has no muscular or tendinous attachments, it is protected by its deep location in the ankle mortise as well as its ligamentous attachments and capsular support. Forced plantar flexion and inversion can result in an anterolateral TTD, with rotation of the talus 90 degrees in the axial and sagittal planes. The talus is predisposed for AVN as the majority (60%) of its surface is covered by hyaline cartilage, leaving only a limited portion to receive adequate blood supply from the delicate anastomoses of anterior tibial, posterior tibial and peroneal arteries. Trauma or surgical manipulation of the soft tissues surrounding the talus can jeopardise this delicate blood supply.

The majority of TTD cases are open and half of them have associated fractures. Weston et al. reported 85% of their 86 TTD cases were open and 50% of them had accompanying fractures (2). Closed isolated TTD therefore represents an even rarer entity; the same review reported only 9% of their cases to be as such. Whilst open wounds or associated fractures may necessitate operative treatment, closed isolated TTD has the unique opportunity to be treated conservatively. Clinicians therefore encounter a clinical decision of whether to treat any accompanying ligamentous injuries operatively to ensure stability of the tibiotalar joint, at the risk of impacting the delicate blood supply of the talus which will potentially lead to AVN.

In our case, the young age and high employment demands (construction worker) of the patient led us to consider workup and operative treatment of ligamentous tears. MRI subsequently revealed significant tears of ATFL, deep DL, CFL and PTFL. However, as the patient did not exhibit any ankle instability symptoms and signs there was no need for operative ligamentous repair that may have jeopardized the blood supply to the talus. 2 case reports by Shahraree et al. and Hosny et al. have highlighted that the preservation of the deltoid or posterior process branches prevented AVN in their patients (6, 7). Xarchas et al. details that there is clinical and radiological (bone scan, MR angiogram) evidence to suggest that the vascularity of anterolateral TTD can be maintained by branches of the anterior soft tissues (8). As long as the supply from one of the three major arteries is preserved, the AVN risk of the talus can be reduced (9).

Interestingly in our case the superficial DL remained intact and we hypothesise that this may suggest preserved blood supply from the tarsal canal and deltoid branches of the posterior tibial artery. It is also important to note that despite multiple significant ligamentous injuries, our patient achieved good pain control, range of motion and stability of ankle despite being treated conservatively. 4 case reports also highlight similar outcomes with conservative treatment of closed isolated TTD (4, 9, 10, 11).

Conclusion

We report a very rare case of closed isolated TTD, with significant ligamentous injuries, that was successfully treated conservatively without AVN or instability complications. Clinicians should prioritise protecting the delicate blood supply to the talus. Our case highlights that despite significant ligamentous injuries, good pain control, range of motion and stability of ankle is achievable. We attribute the successful outcome to 1) timely closed reduction of the TTD, 2) not needing operative repair of the ligamentous injuries that could have damaged the delicate blood supply to the talus, and 3) early physiotherapy and mobilisation of the ankle.