Femoral interference screw divergence after anterior cruciate ligament reconstruction provoking severe anterior knee pain.

An unusual case of anterior knee pain after anterior cruciate ligament reconstruction secondary to femoral screw divergence is described. We hypothesize that a contracture of the lateral head of the gastrocnemius, caused by irritation from the femoral screw, could increase the patellofemoral joint reaction. This would contribute to increasing the overload of the subchondral bone, which could explain the anterior knee pain. Conversely, tight gastrocnemius may lead to an increase in foot pronation of the subtalar joint, resulting in an increased valgus vector force at the knee, which can cause anterior knee pain. Finally, dorsiflexion of the talocrural joint will also decrease if the gastrocnemius is tight, provoking biomechanical limitations and possible knee problems during walking and running.