Patellar osteolysis after total knee arthroplasty with patellar resurfacing: a potentially underappreciated problem.

Osteolysis of the patella following total knee arthroplasty is both uncommon and poorly described in the literature. We describe 3 cases of total knee arthroplasty with patella resurfacing that later presented with anterior knee pain with patellar osteolysis without evidence of patellar implant failure: 2 males and 1 female patient, all with bilateral knee osteoarthritis. Osteolysis of the patella was identified radiographically between 2 and 16 years from the index procedure. We theorize that high pressures across the patella-femoral joint, in obese or muscular patients, may play a role in the formation of these patellar osteolytic lesions. We suspect that the prevalence of this phenomenon is under-recognized in the literature and may increase with longer term follow-up and awareness.