Hypermobility of joints

Abstract

In the last three decades more subtle patterns of hypermobility have been associated with common disorders of paediatric importance. Carter and Wilkinson devised clinical procedures to show that children who have congenital hip dysplasia and their first degree relatives tend towards generalised hypermobility. Subsequent studies have shown other musculoskeletal associations of articular hypermobility and have drawn attention to the relatively common benign hypermobility syndrome. Routine clinical assessment of hypermobility does not require special equipment. Mechanical devices reported for research purposes have not supplanted the simple Carter-Wilkinson type of clinical manoeuvres. In modified form, the procedures are passive apposition of the thumbs to the flexor aspect of the forearm, passive dorsiflexion of the fifth finger beyond 90°, hyperextension of the elbows beyond 10°, hyperextension of the knees beyond 10°, and ability to place the palms of both hands flat on the floor with the knees held in extension. By this method a score can be assigned, with a maximum of nine, one point for each of the paired limb procedures and one point for spinal hypermobility; a mobility score of four or greater may be considered hypermobile. The spinal flexion test is the least useful in that performance is influenced by age, limb length, and even the repetitive hamstring stretching of ballet training. Of course, hypermobility may be demonstrable in other joints such as the wrists or finger joints, and the latter may be particularly impressive in 'collagenopathies' such as Ehlers-Danlos syndrome. The frequency of abnormal mobility varies according to joint, with the knees and elbows remaining hypermobile later in life than the wrists or ankles. The expectation that symptoms occur only in children who are generally hypermobile may lead to underrecognition of localised hypermobility associated symptoms. Hypermobility of joints is a common clinical finding and is not symptomatic in the majority of children. In general, girls have greater mobility of joints than boys of the same age, ranges are usually greater in the non-dominant limb, and Asians are more mobile than whites. Carter and Wilkinson reported hypermobility in 7% of 285 healthy children aged 6 to 11 years. A more recent American study found generalised hypermobility in 12% of normal schoolchildren and 66% of 32 children with 'juvenile episodic arthralgia'.