NON-REDUCIBLE LATERAL PATELLAR DISLOCATION IN A HIGH SCHOOL FOOTBALL PLAYER

Abstract

532 HISTORY - A 16-year old junior high school football wide receiver sustained a left knee injury while attempting to catch a pass. His knee was planted when he twisted to his right to catch the ball and felt a painful "pop". He immediately fell to the ground as the play ended. His injury occurred within ten yards of the host team physician. He had never injured either knee nor had any patellofemoral problems in the past. PHYSICAL EXAMINATION - On the field, the patient was found to be writhing in pain and clutching his left knee. He was lying on his back with his knee in slight flexion. His patella was obviously dislocated laterally. His tibiofemoral alignment appeared normal. After verbal reassurance, his knee was passively extended without reduction of the patella. The medial border of the patellar appeared to be stuck against the lateral femoral condyle. His quadriceps showed minimal spasm. The remainder of his extensor mechanism appeared to be intact. His level of pain and obvious primary diagnosis precluded careful exam of other knee structures. Both medial and anterior pressure from the undersurface of the patella failed to achieve reduction despite multiple attempts. NON-REDUCIBLE LATERAL PATELLAR DISLOCATION IN A HIGH SCHOOL FOOTBALL PLAYER DIFFERENTIAL DIAGNOSIS: 1. patellar dislocation 2. patellar fracture 3. distal femoral fracture TESTS AND RESULTS - An ice bag and splint were placed and the patient was transported to a local emergency room. Radiographs there confirmed the presence of lateral patellar dislocation without fracture. The emergency room physician was also unsuccessful at reduction despite parenteral narcotics and diazepam. A local orthopedist was consulted who also had difficulty on multiple attempts despite hyperextension of the knee and medial pressure on the patella. After 1% xylocaine was injected into the knee joint, the patella finally reduced. Post-reduction films were negative for fracture or loose body. FINAL DIAGNOSIS: Lateral patellar dislocation with difficult reduction TREATMENT: 1. Patellar sleeve with lateral buttress 2. Ice, OTC ibuprofen 3. Protected weight bearing as tolerated 4. Protected range-of-motion exercises 5. Open chain strength exercises 6. Biomechanical assessment