Adult Anterior Knee Pain (AKP), direct trauma.

The patient was a 32-year-old heavy equipment operator, completely healthy otherwise, who had fallen directly on his right knee 6 years prior to presentation. He simply did not get better.

He did not exercise regularly but was very active in his work, which involved significant mechanical lifting. The knee had been painful ever since the fall, a deep parapatellar ache which varied in intensity. It did not go to either joint line but did travel down the front of the calf sometimes. He had pain with the act of entering and exiting these machines, as he had frequently to do throughout the day. For several months before I saw him the knee had been increasingly painful. His wife had observed swelling and he was now limping on regular occasions. He complained that he was uncomfortable when he sits and on getting up from sitting. He was unable to sit for prolonged periods. His leg was more comfortable in extension. Snapping and popping occured when he walked or when he got up from sitting.

Examination

He was modestly overweight with a BMI of 40.9. Axial alignment of his legs was normal. He had mobile pes planus. The involved right knee did not hyperextend; there was parapatellar tenderness; Hoffa’s sign was positive; range of motion normal; stable in all planes.

Investigations

Radiographs were normal. CBC, ESR, C-reactive protein and rheumatology screen normal.

MRI: synovial cyst located in the fat pad adjacent to the anterior cruciate insertion; an infrapatellar plica is present.

Management

As he was markedly symptomatic, he underwent arthroscopic evaluation. The operative findings included: an infrapatellar plica (fenestrated vertical septum type); grade 2 chondromalacia patellae along the central ridge; grade 2 osteoarthritic change involving the weight bearing surface of the medial femoral condyle; synovial proliferation present adjacent to the ACL insertion.

The procedure involved: release and removal of the IPP (untethering the fat pad); debridement of the wall of the cyst; chondroplasty of the patella and medial femoral condyle.

The result at 18 months was a pain-free knee, and a return to work with no limitations.

 

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