Back to Basics: A Case of Traumatic Knee Pain

By Dr. Ozair Rizvi, MD

A 45 year-old male with no medical history presents with Right knee pain after a mechanical fall causing him to land onto his right knee. Exam reveals moderate swelling and tenderness. He is unable to extend the knee.

X-ray shows:

Diagnosis: Patella Alta

What is it?

Superior displacement of the patella due to disruption of the tendon attaching the patella to the tibial tubercle.

Mechanism

• Tensile overload of the extension mechanism
• Most commonly occurs with the knee in a flexed position
• Local steroid injection associated with increased risk of spontaneous rupture

Symptoms

• Pain, greatest in infrapatellar region
• Swelling of the knee due to hemarthrosis
• Popping sensation
• Difficulty weight-bearing

Physical exam

• High-riding patella
• Hemarthrosis and ecchymosis
• Localized tenderness
• Reduced ROM of knee (impaired knee extension and weight bearing) due to pain
• Possibly a palpable gap below the inferior pole of the patella

Management

• If partial tear with intact extensor mechanism, likely nonoperative management with immobilization in full extension (knee splint).
• If complete tear and loss of extensor mechanism, requires orthopaedics consult and possible operative repair.

References:

Chen SK, Lu CC, Chou PH, et al. Patellar tendon ruptures in weight lifters after local steroid injections. Arch Orthop Trauma Surg 2009; 129:369.