805 THE JOURNAL OF BONE AND JOINT SURGERY TRANSIENT SYNOVITIS AND PERTHES ’ DISEASE IS THERE AN AETIOLOGICAL CONNECTION?

A prospective study was made of 1 19 children with transient synovitis or any other cause for synovial effusion and elevated intra-articular pressure. During a follow-up of one year not one case of Perthes ’ disease was diagnosed and the late clinical and radiographic changes were minimal with moderate overgrowth of the femoral head in 33 % and widening ofthejoint space in 14.2%. Our results do not support the widely accepted concept that Perthes ’ disease develops as a result of the period of elevated intra-articular pressure found in transient synovitis. Further research into this and Perthes’ disease should follow the premise that they are two different diseases without any aetiological connection. Transient synovitis of the hip has been recognised as a clinical entity since it was first reported in 1892 by Lovett and Morse. It was accepted as a self-limiting disorder of unknown aetiology until Ferguson and Howorth (1934) pointed out that some patients with transient synovitis developed Perthes ’ disease. Since then transient synovitis has been associated in long-term follow-up studies with such pre-arthritic conditions as coxa magna and with osteoarthritis itself(de Valderrama 1963). Clinically, transient synovitis and Perthes ’ disease may be indistinguishable, presenting with limited or painful joint movement in patients of similar age and sex distribution. This has encouraged the search for a common pathogenesis. One favoured hypothesis is that the unique vascular anatomy of the developing hip is affected by the synovial effusion and elevated intra-articular pressure of transient synovitis. The vessels supplying the growing epiphysis run intra-articularly and subsynovially, and are vulnerable to compression b