HISTORY: A 20 year old collegiate rugby player sustained a right knee injury. A defender struck the front of his right knee resulting in hyperextension and an audible pop. He was unable to ambulate off of the field. Initial exam revealed a dislocated knee which was reduced on the field. He was taken to the ED where a CT angiogram ruled out vascular injury. He was provided with an immobilizer, crutches and was referred to a sports medicine trained orthopedic surgeon. PHYSICAL EXAM: Examination in clinic demonstrated a marked effusion. Passive range of motion showed flexion to 50 degrees, and hyperextension into mild recurvatum. Varus and valgus stress revealed increased laxity for both. Lachman’s was markedly positive. He demonstrated a complete foot drop with 0/5 strength for dorsiflexion, eversion, and extensor hallicus longus (EHL). Plantarflexion and inversion had full strength. Sensory testing showed diminished light-touch over the lateral lower leg and the dorsum of the foot. DIFFERENTIAL DIAGNOSIS: 1. Anterior cruciate ligament (ACL) tear 2. Posterior cruciate ligament (PCL) tear 3. Medial collateral ligament (MCL) tear 4. Lateral collateral ligament (LCL) tear 5. Sciatic nerve injury 6. Common peroneal nerve injury 7. Superficial peroneal nerve injury 8. Deep peroneal nerve injury TESTS AND RESULTS: Right Knee MRI: -ACL tear -PCL tear -LCL tear -Popliteus tendon tear -Posterior lateral capsule tear -Both gastrocnemius tears -Posterior capsule tear FINAL WORKING DIAGNOSIS: -ACL tear, PCL tear, LCL tear, Popliteal tendon tear, posterior capsule tears, gastrocnemius tears, and a common peroneal nerve injury TREATMENT AND OUTCOMES: 1. The patient underwent arthroscopic reconstruction of his ACL and PCL, open LCL reconstruction, posterior lateral corner reconstruction, and a common peroneal nerve decompression. 2. He is undergoing physical therapy and he has advanced his range of motion back to normal. He continues to work on his quadriceps strength, hip flexor strength, balance and neuromotor control of the knee. 3. The patient experienced improved sensation in the peroneal nerve distribution and slight EHL activation at 52-days post surgery. This has continued to improve and the patient is able to dorsiflex, evert and activate his EHL against resistance at four months post surgery. Sensation is much improved.