Introduction: Posttraumatic osteoarthritis of the ankle joint usually occurs secondary to an intraarticular fracture of the weight bearing ankle joint. The question whether also recurrent ankle sprain and /or chronic instability alone can cause this entity, is, however, still a question to debate. The aim of this retrospective study was, therefore, to analyse the history and findings of a consecutive series of patients that were treated for post-traumatic end-stage osteoarthrosis of the ankle.

Methods: The complete database (including physical exam, standard radiographs, patient questionnaire and AOFAS hindfoot score) of all patients was analysed.

Results: Out of 268 patients (females, 135 patients; males, 133) 221 (82.5%) had had a fracture (Fx) and 47 (17.5%) suffered from chronic ankle instability with recurrent sprains (but did not have a fracture). The latter group could be subdivided into 29 (10.8%) patients with recurrent sprains (RS) and 10 (6.7%) patients with only a single sprain (SS). The mean (range) delay between primary trauma and surgical treatment for endstage osteoarthritis was 21.1 (1–58) months for Fx, 37.07 (1–61) months for RS and 22.5 (5–48) months for SS.

Conclusion: Obviously, not only fractures, but also severe sprains and /or chronic instability play an important role as a cause of end stage osteaorthrosis of the ankle joint. The obtained results suggest that a single severe sprain (dislocation) can cause similar articular damages to an intraarticular fracture, as the time to develop osteoarthrosis does not differ. This is in contrast to the current opinion that ankle sprain, in most instances, does not result in symptomatic articular degeneration.