Static or dynamic repair of chronic lateral ankle instability. A prospective randomized study.

In a prospective study, 82 patients with 89 chronic lateral unstable ankles were randomly allocated to either static (Group S) or dynamic (Group D) reconstruction. For static reconstruction a procedure involving the distal part of the peroneus brevis tendon was used. The bore holes in the lateral malleolus were placed at the insertions of the original ligaments. For dynamic reconstruction the anterior one-half of the peroneus brevis tendon was used. On muscular contraction the split tendon will slide through a bore canal in the lateral malleolus. Theoretically, both procedures can stabilize the ankle and subtalar joint. Fifty-six patients were assigned to static reconstruction and, because of thin tendons, only 26 were assigned to dynamic reconstruction. Thirty-three cases had increased subtalar mobility. All patients had standardized clinical and roentgenographic examinations preoperatively and at nine and 25 months postoperatively. At the 25-month follow-up examinations the clinical results were best in Group S. The number of reinjuries was highest in Group D, and two patients had given up sports. The inversion movement was most restricted in Group S but without functional importance. A significant reduction of talar tilting and anterorotational talar displacement was seen in both groups but was most pronounced in Group S. Also, postural balance improved in both groups. Complications in Group S were venous thrombosis in two patients, dysesthesia in the cicatrix in two, hyposensibility of the lateral foot edge in one, and calcification at one bore hole in one patient. Complications in Group D were hyposensibility and dysesthesia in the cicatrix in one patient. The static procedure is recommended for reconstruction of chronically unstable ankles, especially if associated with increased subtalar mobility.