Osteophyte evolution: studies in an experimental partial meniscectomy model.

Osteophytes are considered characteristic manifestations of osteoarthritis (OA) but may be seen independent of structural cartilage erosive lesions. Etiopathogenic mechanisms for osteophyte formation may involve responses to synovial inflammation, stretching of the synovial membrane, general mechanical instability, and vascular metaplasia. Experimentally induced OA following partial menisectomy in rabbits demonstrates active cellular replication at the normal joint periphery. Vascular responses are seen late in parallel with osteophyte formation rather than preceding it. Osteophyte ossification is primarily endochondral. The parallel stimulatory response to perichondrium, cartilage, and bone allows speculation on the interplay of mechanical/electrical forces and chemical/hormonal transducers in the development of osteophytes.