Anterior dislocation of the tibio–talar joint without diastasis or fracture—A case report
Article Outline
Abstract
We present a 27-year-old man with pure anterior dislocation of the ankle joint following a fall from height. There were no accompanying fractures in and around the ankle joint. The injury was initially missed on clinical examination in view of minimal ankle deformity. The patient was managed conservatively with closed reduction and plaster immobilisation. The case report highlights the importance of early diagnosis and management of anterior ankle dislocation to obtain good functional outcome. A review of the literature on this rare injury is also presented.
Keywords: Ankle, Dislocation, Anterior, Closed
1. Introduction
Closed dislocation of the ankle without fractures is an unusual injury. Occurrence of closed anterior tibiotalar dislocation without fracture and diastasis of the syndesmosis is an extremely rare injury. We present here a 27-year-old man with a pure closed anterior ankle dislocation following a fall from height. Early diagnosis of this rare injury is often missed in view of minimal deformity at the ankle joint. Management of this painful injury is essential for good long-term functional result. A review of the literature is also presented.
2. Case report
A 27-year-old man was brought to the Emergency department following a fall from a height of approximately 7
ft. He had pain and swelling of the right ankle joint. There were no other injuries and he was hemodynamically stable. His Glasgow Coma Scale was 15/15. On examination of the left ankle there was swelling around the joint with diffuse tenderness. Bony ankle deformity was very minimal and was missed on the initial examination by the Accident & Emergency resident. The overlying skin was tense with no open wound. There was no distal neuro-vascular deficit. An X-ray of the ankle joint (Fig. 1a and b) showed an anterior dislocation of the ankle joint with no other associated fracture or widening of the tibiofibular syndesmosis.
Fig. 1.
(a) X-ray of the ankle (lateral view) showing the anteriorly dislocated ankle joint. There are no associated fractures. (b) AP view of the same ankle (no widening of the syndesmosis noted).
Immediate closed reduction of the ankle joint was performed under general anaesthesia. No widening of the syndesmosis was observed on fluoroscopic examination with stress applied to the ankle. The ankle was immobilised in a short leg cast. Post-reduction radiographs showed normal restoration of the ankle joint. The cast was maintained for 5 weeks. Range of motion exercises were then started and walking was allowed with partial weight bearing. Full weight bearing was permitted at 8 weeks. The patient was symptom free with near normal ankle movements, at the last follow-up, 2 years after the injury.
3. Discussion
Dislocations of the ankle joint without concomitant fractures were called “luxatio pedis cum talo”, or “talus fixed to the foot” by Ehalt [1]. A number of sporadic case reports of ankle dislocations without fractures are present in the literature [2], [3], [4]. Closed anterior dislocation of the tibio–talar joint without fracture or diastasis is a very rare phenomenon. Review of the English-language literature disclosed only four previously reported cases.
Wilson et al. [5] in a review series of ankle dislocations in 1938 noted that Scharsich had reported two cases of anterolateral ankle dislocations. These injuries were treated conservatively with satisfactory results. Segal and Wasilcwski [6] reported what they presumed to be an anterior dislocation of the ankle in a motorcyclist. They used stress radiograms to evaluate the integrity of the talonavicular and subtalar joints. They were in real sense dealing with a total talar dislocation. A neglected 1-week-old anterior dislocation of the ankle is described by Scott [7]. The injury was missed on initial examination in a case of polytrauma. The injury was also missed clinically in our case as the deformity was minimal as against the prominent deformed ankle of a posterior dislocation.
Anterior dislocation of the ankle with associated fracture of the trigonal process has been described in a 21-year-old motorcyclist by Segal et al. [8]. The case was treated conservatively. Their patient had an unusual complication of post-traumatic peroneal tendon dislocation following the injury. They feel that presence of peroneal tendon dislocation is fairly common in this injury and should not be overlooked at the time of injury. Although there was no clinical evidence of a peroneal tendon injury in our patient, it is imperative to be aware of this unusual injury in patients with anterior ankle dislocation. Clinical detection of peroneal tendon injury is imperative in view of low threshold for imaging modalities to pick this complication.
Ankle dislocations occur when significant force applied to the joint results in loss of opposition of the articular surfaces. Because of the large amount of force required and the inherent stability of the joint, dislocation is rarely seen without associated fracture. The mechanism of anterior dislocation of the ankle is forced plantar flexion [7]. The direction of dislocation without fracture of the malleoli corresponds to the plane of greatest freedom of motion, either anterior or posterior. With foot in extreme plantar flexion, the narrowest part of the talus lies within the ankle mortise, allowing for anterior dislocation [8]. In our patient forced plantar flexion occurred following the entrapment of the ankle on to the ladder rung with the body weight acting as the deforming force. None of the case reports had a similar mechanism of injury. In fact all previously reported cases of anterior dislocation ankle were seen in motorcyclists involved in road traffic accidents.
To conclude, anterior dislocation of the ankle is an easy dislocation to reduce. Closed management of the injury led to a good outcome in our case. Since the deformity is not as pronounced, as in a posterior dislocation, early recognition of the injury by the accident and emergency staff is necessary to prevent subsequent neuro-vascular problems.
References
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PII: S1268-7731(07)00088-4
doi:10.1016/j.fas.2007.09.003
© 2007 European Foot and Ankle Society. Published by Elsevier Inc. All rights reserved.
