A Clinical Review of the Hyperlaxity of Joints with Particular Reference to Osteoarthrosis

Abstract

The range of observed movement at a given joint varies with a gaussian distribution throughout the population. Individuals whose joints display an unusually high degree of laxity are susceptible to a variety of rheumatic and orthopaedic symptoms. The impression that such individuals develop premature osteoarthrosis is a strong one, but hard to prove. In addition, certain individuals with inherited abnormalities of connective tissue are undoubtedly at risk of accelerated osteoarthrosis. The observed range of movement at a joint is determined by a variety of factors. The main ones are the muscular tone, the laxity of the collagen that contributes to the joint capsule and surrounding structures, and the shape of the articulating bony surfaces. The first of these is probably neurologically mediated, the latter two are usually genetically determined. In a majority of cases it is probably the mechanical joint instability that produces the articular damage, though the alternative hypothesis is that the osteoarthrosis is initiated by genetic aberrations in the collagen that coincidentally cause lax joints. Clinical and family studies using the Leeds Hyperextensometer will help to clarify this and it remains a possibility that genetic markers may point to those individuals who will be at particular risk of osteoarthrosis should joint hyperlaxity develop.