Sixty consecutive collegiate athletes with "high" ankle symptoms were prospectively evaluated over a 3-year period in an effort to better define this debilitating ankle injury. All athletes included in this study had tenderness over the distal anterior tibiofibular ligament, tenderness proximally along the interosseous membrane, and functional disability. No study subject had a fracture or frank tibia-fibula diastasis. The severity of the sprain was quantified using the interosseous "tenderness length." A standard rehabilitation protocol was followed by all patients. Athletes returned to competition when they could perform all functional testing without difficulty. Time to return to full competitive activity averaged 13.4 days. The number of days missed from competition was statistically related to the interosseous tenderness length (P = 0.0001) and to positive results on the squeeze test (P = 0.03). Fifty-three of the 60 injured athletes were evaluated at least 6 months after injury. Patients rated their outcomes as good or excellent. Six of the patients experienced occasional ankle pain and stiffness, four patients reported recurrent ankle sprains, and one patient had heterotopic ossification formation.