The indication for surgical treatment of posterior malleolar fracture

Objective To explore the indication for surgical treatment of posterior malleolar fracture by observing the effects of bone fragment size and fixation on the fracture healing.Methods We retrospectively analyzed 73 patients with posterior malleolar fracture who had undergone surgical treatment from January 2004 to December 2011.By AO classification,there were 19 cases of type 44A,37 cases of type 44B and 17 cases of type 44C.Fixation of the posterior malleolus was conducted in 30 cases (45.2％) and not in 43 cases (54.8％).American Orthopaedic Foot and Ankle Society (AOFAS) score and the Mos 36-item Short Form Health Survey (SF-36 score) were used for functional evaluation.Articular smoothness and degeneration in the X-ray films were considered as image evaluation criteria.The AOFAS and SF-36 scores were compared between the fixation and non-fixation groups as well as between the ≥25％ bone fragments and the ＜ 25％ones.Results Sixty-five patients completed the follow-ups which ranged from 2 to 84 months (average,44.3 months).Irregular articular surface was observed in 4 cases and mild to moderate degeneration in 5 cases.Infective infection of the lateral malleolar skin occurred early in 2 cases and poor internal implantation in one,but their functional recovery was not affected.The AOFAS and SF-36 scores for patients with ≥25％bone fragments in the fixation group were respectively 94.2 ± 9.8 and 107.5 ± 11.8 points,significantly higher than those in the non-fixation group (87.4 ± 6.7 and 92.8 ± 18.5 respectively) (P ＜ 0.05).The AOFAS and SF-36 scores for patients with ＜ 25％ bone fragments in the fixation group were respectively 91.3 ± 13.2 and 104.2 ± 14.2 points,with no significant differences from those in the non-fixation group (91.8 ± 10.9 and 102.3 ± 16.6 respectively) (P ＞ 0.05).Conclusions When a posterior fragment is larger than 25％ of the articular surface,open reduction and internal fixation should be considered.When a posterior fragment is less than 25％ of the articular surface,conservative treatment may be a better choice. Key words: Ankle;  Fracture;  Prognosis