Ankle rotators strength and functional indices following operative intervention for ankle fractures

Background: Outcome measures of operative intervention for ankle fractures indicate poor subjective and objective results. Though patients regain full range of motion they often complain of pain and fatigability. Specifically, there is a paucity of data regarding strength characteristics of the relevant muscles after surgical intervention. Objective: Describe the strength characteristics of ankle invertors (INs) and evertors (EVs) and explore their relationship to the ankle-hindfoot scale (AHS) in patients after surgical intervention for ankle fractures. Method: Bilateral isokinetic concentric and eccentric INs and EVs strength was measured in 24 patients, 6-12 months following surgery. Additional subjective and objective factors were evaluated using the AHS. Results: Strength of the involved limb muscles was significantly lower compared to the contra-lateral muscles (p<0.0001). However, strength reduction was significantly greater in the INs (27.6-37.5%) than the EVs (14.4-24.3%), (p=0.0005). The EVs/INs ratio of the uninvolved limb (89-102%) was significantly lower than the ratio of the involved limb (111-141%), (p<0.0001). The clinical status of the limb was found to have a significant effect on all dynamic control ratios (DCRs): EVR(E)/INV(C), INV(E)/EVR(C), EVR(C)/INV(E), and INV(C)/EVR(E) (P<0.0001, P=0.0032, P=0.0001, and P=0.0015, respectively). A significant relationship was found between the mean AHS score and relative unilateral weakness (r=-0.58, p=0.003). Conclusions: Strength reduction could be one of the reasons for the functional decline following ankle fractures. The weakness of the INs muscles of the ankle is more pronounced than that of the EVs.