Knee joint radiographs from 250 joints with primary osteoarthritis (OA) and 48 with articular chondrocalcinosis (CC), aged 65 or older, were compared.
Presence of femoral cortical erosion (FCE) in OA and CC, relation to CC and patello-femoral osteoarthritis (PF-OA), position of the patella and the femur during extension of the knee (patello-femoral distance) and configuration of the patella (attrition rate and T-angle) were evaluated.
We found FCE in 9 joints (19%) with CC, but none with OA. Knees showing FCE in CC had higher mean PF-OA grade, and the upper end of their patella almost touched the femur during extension of the knee. There was a tendency that the patella with larger attrition rates had smaller T-angles, and that the patella showing FCE was in a so-called “patella wrapped around the femur” configuration.
We concluded that local mechanical factors played an important role in the FCE formation in CC associated with PF-OA.
