Complications of the PCA anatomic patella

A retrospective review of the total knee arthroplasties performed using the PCA anatomic patella (Howmedica, Rutherford, NJ) was undertaken after a high rate of complications was noted. Eighty-seven knees in 75 patients were evaluated with an average follow up of 16 months. Eighteen complications of the patella in 14 knees were found (16%); these included lateral subluxation (10 knees), fracture of the patella (5 knees), patellar tendon rupture (2 knees) and prosthetic loosening (1 knee). Seven patients required secondary procedures with the ultimate result greatly compromised in four patients. It is proposed that if the component is not precisely aligned, the eccentric shape and central ridge increases the forces acting at the patella and leads to an increased risk for complications, making the component less forgiving than the more standard dome-shaped patellar component.