Transitory Synovitis of the Hip in Children.

TRANSITORY synovitis is a condition of unknown aetiology affecting the hips of children under the age of I4. It is characterized by the sudden onset of pain in the joint with limitation of movement. It is not clearly related to trauma. There are rarely any radiological changes, and other investigations are essentially normal. The condition spontaneously regresses and no specific treatment is known. The condition was first noted by Todd (1925) and Fairbank (I926). It has also been called coxitis fugax, coxitis serosa, irritable hip and observation hip. Butler wrote about the condition in 1933, differentiating it from tuberculosis but since then it has seldom been mentioned in British journals (McMurray, I947; Caravias, 1956; de Valderrama, I963; Adams, I963). Miller (I93I) reported 77 cases from the U.S.A. and suggested that synovitis of the hip was secondary to small epiphyseal abscesses. He found a focus of infection elsewhere in all his cases, but he did not aspirate any of the hips. Finder (1936) followed 20 cases for an unrecorded period and reported no untoward sequelx. Rauch (1940) published another series of 37 cases reporting recurrent attacks and suggesting an increased incidence in spring and summer. Ten American authors in the 1950's reported series of cases but many of their children were not admitted to hospital, nor were they fully investigated. Spock (I959) noted that the condition is rarely reported in negroes. Most authors report a preponderance of males, the hips being equally affected. Simultaneous involvement of both hips has not been reported nor has simultaneous involvement of other joints. The commonest age range is 4 to 8 years with a scatter from i to 14. A seasonal variation is reported by Rauch (1940) and Ebert (I960). The onset of pain is frequently sudden and often at night. There is limitation of movement of the affected hip. Radiographs show only soft tissue swelling around the joint (Drey 1953). There is rarely any great disturbance of temperature, sedimentation rate or white cell count. Most authors treat their patients by bed rest and traction. Recovery within a few weeks is the rule. Butler (I933) said he followed his I9 cases for 3j years while he and Finder (I936) report no sequelke. Fox (1956) reported 2 cases of coxa plana from 9 patients while Spock (1959) reported 2 cases from 4I-but these 4 cases of coxa plana are an entirely separate condition. Tudor (I960) said he folloWed his ii8 cases for up to io years and found no case of coxa plana. Nevertheless de Valderrama (I963) surveyed 23 patients I5 to 30 years after their illness and found varying degrees of coxa magna, osteoarthritis or simple broadening of the femoral neck in 12 of these. Adams (I963) in a shorter follow up of a smaller number of cases found no evidence that transient synovitis led to later avascular changes in the femoral head. There is some speculation as to the cause of this condition. Most authors favour an infective cause-an infection in the upper respiratory tract leading to a metastasis or an allergic reaction in the hip. However, only Spock (1959)quotes any results from throat swabs; one-third of his cases produced hxmolytic streptococci. Trauma is a second possible cause but the numbers who recall recent trauma are not convincing. Allergy is a third suggested causative factor but there is no definite evidence, while Tudor (I960) says he has seen no case of synovitis of the hip in 400 allergic children.