Post-traumatic osteoarthritis--a medico-legal minefield.

A consensus view has been obtained from 108 colleagues about four major questions relating to post-traumatic osteoarthritis (OA) posed by a retired judge. In determining the likelihood of OA developing after a fracture, several factors must be taken into account. These include whether the fracture goes through the joint, the resulting angular deformity, the degree of soft tissue damage, the ensuing laxity of the joint, the presence of generalized OA, the involvement of nearby blood vessels supplying the bones of the joint and possibly the degree of immobilization. Lower limb joints are more likely to develop arthritis after injury than arm joints as they carry more load (although it would be wrong to think that arm joints were not load bearing). Occupation is a further factor. Age is thought to be important, with the elderly more at risk immediately, but the younger having longer in which to develop the disease. Younger people are less likely to develop post-traumatic OA, unless there is involvement of the epiphysis or residual angular deformity. Whilst in animals and in some fractures, degenerative changes begin immediately after damage to the joint, in most adults they take at least 2 years. The span is 2-5 years in more severe cases, including fractures of the joint line with a step in the surface, and associated dislocation. Otherwise it may take 10 years. Most of these data are anecdotal or obtained from retrospective surveys. There is great need for prospective work in this field.