[The painful hip--diagnostic possibilities of sonography]

An intraarticular hip process with chondrolysis simulating Perthes disease: a report of five cases

Radiographic findings in Legg-Calvé-Perthes disease (LCPD) are well known. Four classic stages have been described: incipient stage, avascular stage, fragmentation stage, and residual stage. Final femoral morphology is normally coxa magna, which is associated frequently with hypertrophy of the articular cartilage. We describe five patients with a hip process that initially presented clinical and radiographic findings compatible with LCPD. However, none of these patients showed the typical sequence of the radiographic stages. Instead, the early signs were the formation of rounded areas of rarefaction in the epiphysis and/or the metaphysis with considerable surrounding osteoporosis, early narrowing of the articular space, and final coxa breva morphology with signs of osteoarthritis. No condensation or fragmentation stages were observed. The pathologic study showed complete atrophy of the synovial villi with hyaline cartilage and bone necrosis. The patients described herein presented an intraarticular hip process, initially with signs and symptoms similar to LCPD but with an ultimate clinical evolution that differs from ordinary LCPD.

Anterior joint capsule of the normal hip and in children with transient synovitis: US study with anatomic and histologic correlation

PURPOSE

To study the anatomic components of the anterior joint capsule of the normal hip and in children with transient synovitis.

MATERIALS AND METHODS

Six cadaveric specimens were imaged with ultrasonography (US) with special attention to the anterior joint capsule. Subsequently, two specimens were analyzed histologically. These anatomic findings were correlated with the US findings in 58 healthy children and 105 children with unilateral transient synovitis.

RESULTS

The anterior joint capsule comprises an anterior and posterior layer, mainly composed of fibrous tissue, lined by only a minute synovial membrane. Both fibrous layers were identified separately at US in 98 of 116 (84%) hips of healthy subjects and in all hips with transient synovitis. Overall, the anterior layer was thicker than the posterior layer. In transient synovitis compared with normal hips, no significant thickening of both layers was present (P = .24 and .57 for the anterior and posterior layers, respectively). Normal variants include plicae, local thickening of the capsule, and pseudodiverticula.

CONCLUSION

Increased thickness of the anterior joint capsule in transient synovitis is caused entirely by effusion. There is no US evidence for additional capsule swelling or synovial hypertrophy.

Missed slipped capital femoral epiphysis: illustrative cases and a review

Slipped capital femoral epiphysis (SCFE) is a fairly common condition affecting older children and adolescents, and has the potential for long-term, crippling sequelae. Early recognition is the single most important controllable factor, but the diagnosis is often missed or delayed, resulting in progression of the slip. A SCFE should be suspected and promptly evaluated in any older child or adolescent presenting with a limp or complaints of hip, groin, thigh, or knee pain, especially if the patient is overweight. The diagnosis is usually made by anteroposterior and frog-leg lateral radiographs of the hips. Common errors at initial presentation include: not obtaining hip radiographs (due to either no hip pain or the lack of an impressive history and physical findings); misreading hip radiographs (the findings can be subtle); and lack of timely referral. Early involvement of and treatment by an orthopedic surgeon can greatly reduce the potential complications. We present three cases of SCFE that highlight common errors made at initial presentation, and a discussion that includes the differential diagnosis of an older child or adolescent with a painful limp.