Osteochondrosis of Superior Pole of Patella

Clinically young male patient with athletic background complaining of typical unilateral anterior knee pain. Marked tenderness at the superior pole of patella.

This MRI study of knee joint shows abnormal irregularity, fragmentation with sclerosis involving superior pole of patella. An associated thickening of quadriceps tendon. 

Knee joint effusion.

Imaging findings consistent with osteochondrosis of patella at superior pole.

Osteochondrosis of the superior pole of the patella

Osteochondroses are the heterogeneous group of injuries to the epiphyses and apophyses of children or adolescents, are actually osteonecrosis owing to repetitive microtrauma and avulsion injuries at tendinous insertions. Imaging wise characterized by bone fragmentation and sclerosis.

There are two well-known such syndromes associated with knee joint, one is Osgood-Schlatter disease, an avulsion of the tibial tuberosity and another is Sinding-Larsen-Johansson disease, a chronic avulsion injury involving lower pole of the patella at the insertion of patellar tendon.

The less well described osteochondrosis at the superior pole of patella appears secondary to similar mechanism associated with quadriceps tendon insertion, a rare cause of anterior knee pain in children between 5 and 10 years of age, usually single knee is affected but bilateral cases have also been reported.