Module 63, Pediatric Orthopaedist Level

This 16 year old, 220 pound male presented to the emergency room after sustaining an acute injury to his right knee while playing baseball. The patient related that he noticed acute onset of pain in the right knee after striking out at bat. He heard a single clunk in his knee and noticed immediate pain and swelling. On examination he was noted to have medial knee tenderness with a mildly positive apprehension test. His ACL, PCL, MCL and LCL ligaments were intact. He was placed into a knee immobilizer and told to follow up in the Sports Medicine clinic. He presented to Sports Clinic 6 days later with a reporting the knee "gave out" on him several times since the accident. On physical exam of the patient, six days after injury the knee was noted to have a large effusion. ROM was limited from 20 to 100 degrees of flexion. There was significant medial retinacular tenderness with a mildly positive apprehension test. Based on the radiographs and his clinical exam an arthroscopic examination was performed. At arthroscopy the medial femoral condylar defect was not apparent, but a large retinacular tear was discovered. Also, the patient had an osteochondral fracture of the lateral femoral condyle and a free 7 mm by 5 mm intraarticular cartilage fragment.

Question 63A

The best treatment for this cartilage fragment is to remove it.

Question 63B

An open repair of the medial retinaculum should be performed.

Question 63C

Patella alta and Excessive Q angle are two risk factors for this type of patellar dislocation.

Question 63D

This injury is most commonly associated with in gymnastics, cheerleading, or dancing.

Question 63E

This boy has a substantial risk for repeat dislocation of the patella.