Patella displacement and osteoarthrosis of the knee joint in mice.

Surgical stabilisation of the normally medially--subluxing patella of STR/ORT male mice, prevented the normal development of osteoarthrosis in the medial compartment of the femoro-tibial joint. Surgically produced medial dislocation of the patella in non-arthrosis-prone male CBA/ORT mice often gave rise to osteoarthrosis of the medial condyles. This, with further evidence from previous studies, strongly indicates that the high incidence of degenerative joint disease in male STR/ORT mice occurs because of a tendency of the patella to dislocate medially due to some unknown cause.