The chronister protocol: Early experience with immediate immobilization in flexion and rapid return to play after acute lateral patellar dislocation

Context: Acute lateral patellar dislocation is a common injury sustained by athletes, and often requires several months to recover and return to play. Objective: To describe a novel protocol for the treatment of acute lateral patellar dislocation that returns patients to play far sooner than traditional treatment protocols. Design: Case series and review of the literature. Setting: Division I NCAA institution. Patients: Two collegiate athletes who sustained first-time acute lateral patellar dislocations. Interventions: Traditional standard of care for acute lateral patellar dislocation after reduction involves 1–7 weeks of immobilization in full extension. Knee stiffness commonly results from this method, and return to full activity typically takes 2–4 months. We used a protocol involving immobilization in maximal flexion for 24 hr, with early aggressive range of motion and quadriceps strengthening in the first week after injury. Main Outcome Measures: Time to return to play. Results: Immediate on-site reduction of the patella followed by 24 hr of immobilization in maximal knee flexion was performed. Following an accelerated rehabilitation regimen, patients were able to return to sport an average of 3 days postinjury. Neither patient has experienced a recurrent dislocation. Conclusions: Our protocol is based on anatomic studies demonstrating reduced tension on the medial patellofemoral ligament, reduced hemarthrosis, and reduced soft tissue swelling in maximal knee flexion. This method apparently bypasses the knee stiffness and deconditioning commonly seen with traditional nonoperative regimens, allowing return to sport weeks or months sooner.