Antiresorptive treatment and talar collapse after displaced fractures of the talar neck: a long-term follow-up of 19 patients

Abstract

Background and purpose - Displaced fractures of the talar neck are associated with a high risk of structural collapse. In this observational analysis we hypothesized that pharmacological inhibition of osteoclast function might reduce the risk of structural collapse through a reduction in bone resorption during revascularization of the injured bone.Patients and methods - Between 2002 and 2014 we treated 19 patients with displaced fractures of the talar neck with open reduction and internal fixation. Of these, 16 patients were available for final follow-up between January and November 2017 (median 12 years, IQR 7-13). Among these, 6 patients with Hawkins type 3 fractures and 2 patients with Hawkins type 2b fractures received postoperative antiresorptive treatment (7 alendronate, 1 denosumab) for 6 to 12 months. The remaining 8 patients received no antiresorptive treatment. The self-reported foot and ankle score (SEFAS) was available in all patients and 15 patients had undergone computed tomography (CT) at final follow-up, which allowed evaluation of structural collapse of the talar dome and signs of post-traumatic osteoarthritis.Results - The risk for partial collapse of the talar dome was equal in the 2 groups (3 in each group) and post-traumatic arthritis was observed in all patients. The SEFAS in patients with antiresorptive treatment was lower, at 21 points (95% CI 15-26), compared with those without treatment, 29 points (CI 22-35).Interpretation - Following a displaced fracture of the talar neck, we found no effect of antiresorptive therapy on the rate of talar collapse, post-traumatic osteoarthritis, and patient-reported outcomes.

Figure 1.

Flowchart of patient selection, treatment, and follow-up.

Figure 2.

3-D CT reconstruction of fracture types represented in the study population: Hawkins type 2b (A) and type 3 (B).

Figure 3.

CT of a Hawkins type 3 fracture (A) in a 26-year-old man after a fall from a ladder. The fracture was treated with screw fixation (B), a non-weight-bearing cast for 8 weeks, and alendronate for 6 months. After 12.5 years, the fracture appeared to be healed on CT, showing post-traumatic talocrural OA and partial collapse of the talar dome (C).

Figure 4.

CT demonstrating a Hawkins type 3 fracture of the talus and associated medial malleolus fracture (A) in a 61-year-old man after a crush injury suffered during forest work. The fracture was treated with screw fixation (B), non-weight-bearing cast immobilization, and alendronate for 6 months. At 5.8 years after the surgery, the fracture had healed and the subchondral bone in the talar dome showed fragmentation due to collapse (C). Despite having poor ankle function (SEFAS of 12), the patient declined further surgery.

Figure 5.

CT reconstruction demonstrating a Hawkins type 2b fracture with comminution of the talar dome (A) in a 60-year-old man after a low-energy fall. The fracture was reduced and fixed with 2 screws (B), followed by 6 weeks in a non-weight-bearing cast. No antiresorptive treatment was given. At 11.8 years postoperatively, the fracture was healed and the talar dome showed partial collapse (C). (SEFAS of 24).