Purpose: Fracture of the lateral process of the talus is exceptional. Diagnosis may be missed in 50% of patients, the fracture often being confused with severe ankle sprain. Through the seventies, less than 60 cases were reported in the literature. We report a retrospective study of seven cases treated surgically between 1990 and 2001.
Material and methods: We examined the different mechanisms leading to fracture of the lateral process of the talus and propose a therapeutic algorithm. All patients were seen at follow-up consultations. We used the AOFAS hindfoot evaluation scale, radiographs (anteroposterior view of the ankle and 3/4 lateral view of the foot, Broden views). Outcome was scored excellent, fair, or poor. Mean patient age was 33 years (20–51). Mean follow-up was six years (1–12). The patients incurred the fracture during a snowboard accident (n=1), motocycle accidents (n=3), defenestration (n=1), and mountain climbing accidents (n=2). Fractures resulted from forced eversion in one patient and high-energy trauma in six. Fracture classification according to Hawkins was type 1 (n=4, type 2 (n=3), and type 3 (n=1). Time from the accident to diagnosis was less than 15 days except in one patient where the diagnosis was made ten months after the trauma. Associated lesions were subtalar dislocation (n=2), talar neck fracture (n=1), medial malleolar fracture (n=1), and open fracture of the first cuneiform (n=1). The procedure consisted in fixation of the fragments without resection in four cases, resection of small fragments and fixation of large fragments in two, and osteotomy of a deformed callus of the lateral process of the talus in one. Weight bearing was not allowed four six weeks except in one patient with subtalar dislocation whose calcaneotalar pin was withdrawn at eight weeks.
Results: Complications were one case of superficial infection which resolved with antibiotic treatment and two cases of subtalar osteoarthritis at more than ten years. The overall score was 85 on average. The outcome was excellent in six cases and poor in one.
Discussion: A review of the literature shows that fracture of the lateral process of the talus occurs in 1% of all ankle lesions. Five mechanisms have been described. The two most frequent are ankle inversion in dorsiflexion and high-energy trauma. The three other mechanisms are eversion, direct trauma and stress fracture. The consequences of inadequate treatment include: late healing, non-union, deformed callus (one case in our series), avascular necrosis, subtalar instability, and joint incongruency with risk of subtalar and/or talofibular osteoarthrosis. The appropriate treatment depends on the time of diagnosis, the size and nature of the fracture and the degree of displacement. The therapeutic algorithm used in Geneva is as follows: orthopaedic treatment (plaster resting boot for six weeks followed by physiotherapy) associated with close surveillance in the event of a fracture measuring less than 5 mm which is generally extra- articular. If the patient considers this treatment is insufficient, removal of the fragment can be proposed. For fractures measuring more than 1 cm, which are generally intra-articular, surgical treatment is needed if the fragment is displaced more than 2 mm. In the event of late diagnosis, it may be necessary to remove the fragment or perform subtalar arthrodesis, or as needed resection of a deformed callus. If the diagnosis is established early and appropriate treatment given, the results have been excellent at six years.
