The questionable significance of hip joint tamponade in producing osteonecrosis in Legg-Calvé-Perthes syndrome

Aetiology of Legg-Calvé-Perthes disease: A systematic review

BACKGROUND

Legg-Calvé-Perthes disease (LCPD) is a clinical condition affecting the femoral head of children during their growth. Its prevalence is set to be between 0.4/100000 to 29.0/100000 children less than 15 years of age with a peak of incidence in children aged from 4 years to 8 years. LCPD aetiology has been widely studied, but it is still poorly understood.

AIM

To analyse the available literature to document the up-to-date evidence on LCPD aetiology.

METHODS

A systematic review of the literature was performed regarding LCPD aetiology, using the following inclusion criteria: studies of any level of evidence, reporting clinical or preclinical results and dealing with the aetiology or pathogenesis of LCPD. Two reviewers searched the PubMed and Science Direct databases from their date of inception to the 20th of May 2018 in accordance with the Preferred Reporting Items for Systemic Reviews and Meta-Analyses guidelines. To achieve the maximum sensitivity of the search strategy, we combined the terms: ‘‘Perthes disease OR LCPD OR children avascular femoral head necrosis” with “pathology OR aetiology OR biomechanics OR genetics” as either key words or MeSH terms.

RESULTS

We include 64 articles in this review. The available evidence on LCPD aetiology is still debated. Several hypotheses have been researched, but none of them was found decisive. While emerging evidence showed the role of environmental risk factors and evidence from twin studies did not support a major role for genetic factors, a congenital or acquired predisposition cannot be excluded in disease pathogenesis. One of the most supported theories involved mechanical induced ischemia that evolved into avascular necrosis of the femoral head in sensible patients.

CONCLUSION

The literature available on the aetiology of LCPD presents major limitations in terms of great heterogeneity and a lack of high-profile studies. Although a lot of studies focused on the genetic, biomechanical and radiological background of the disease, there is a lack of consensus on one or multiple major actors of the etiopathogenesis. More studies are needed to understand the complex and multifactorial genesis of the avascular necrosis characterizing the disease.

Doppler sonography of the anterior ascending cervical arteries of the hip: evaluation of healthy and painful hips in children

OBJECTIVE

We evaluated the Doppler sonography of small feeding arteries to the femoral head in children.

SUBJECTS AND METHODS

In a prospective study of 224 hips in 112 patients (mean age, 5 years 11 months), the anterior ascending cervical arteries of the hip were identified with color Doppler sonography. Subsequently, we measured the resistive index (RI) with pulsed Doppler sonography.

RESULTS

In 61% (137/224) of hips, a Doppler signal could be obtained. In asymptomatic hips (n = 64), the mean RI was 0.58. In symptomatic hips, the definitive diagnoses and mean values of RI included transient synovitis (n = 31) and 0.92, Perthes' disease (n = 9) and 0.67, and miscellaneous (n = 5) and 0.68. In 28 symptomatic hips, no definite diagnosis could be determined and the complaints spontaneously disappeared during follow-up (mean RI, 0.57). We found no statistically significant difference in the RI of symptomatic versus asymptomatic hips, except in patients with transient synovitis (p < 0.001). In 11 hips with transient synovitis that were reexamined after 4-6 weeks, the RI returned to normal (0.57). The RI in symptomatic hips showed a positive correlation with the amount of effusion (r = 0.69, p < 0.001). In symptomatic and asymptomatic hips, we found no correlation with age (p = 0.9 and 0.1, respectively).

CONCLUSION

The deep capsular vessels of the hip joint can be evaluated on Doppler sonography in more than 60% of hips. Also, the RI is age independent and correlates with the amount of effusion.

Diagnosis of hip pain in children

Hip pain is uncommon in children and imaging plays a central role in diagnosis and follow-up. The commonest cause of hip pain is acute transient synovitis. Other causes, which vary according to the age group of the child, include Perthes' disease and slipped capital femoral epiphyses. This review discusses the differential diagnosis and imaging pathways required.

Destructive synovitis in contralateral Perthes' disease. A report of 2 cases

2 boys had unilateral Perthes' disease at the age of 5 years. After 6 and 7 years, respectively, both patients developed contralateral femoral head necrosis with rapid destruction leading to ankylosis of the hip. Histology of the synovium showed nonspecific synovitis. Both patients fulfilled criteria for oligo-articular juvenile chronic arthritis (JCA). The association with Perthes' disease suggests a common etiology.

Intraarticular pressure during continuous passive motion of the human knee

Intraarticular pressure (IAP) was continuously monitored during continuous passive motion (CPM) of five normal and 11 abnormal human knees using a new fiberoptic, transducer-tipped Camino catheter. IAP varied in a consistent hysteresis pattern in the normal knees, with subatmospheric pressures recorded at intermediate angles of joint flexion. A similar pattern was recorded in the abnormal knees without cruciate ligament pathology, whereas considerable variability was noted in the knees with cruciate ligament abnormality. IAP was lower in the extension to flexion than in the flexion to extension portion of the CPM cycle, providing evidence of intraarticular fluid flow during portions of the CPM cycle. IAP changes were consistent with "physiologic compartmentation" within the knee at extremes of joint position. Capsular viscoelastic changes and/or synovial fluid volume changes were observed during CPM. The therapeutic mechanism of continuous passive motion may be related to cyclic variation of the intraarticular pressure.

Perthes' disease

Perthes' disease may be regarded as a generalised disorder of cartilage development in which there is a particular predisposition for repeated episodes of infarction in the proximal femoral epiphysis. The resulting deformation of the head is due to collapse of the ossific nucleus and irregular growth of the cartilage. The shape of the epiphysis is determined by the pressure of the surrounding structures. The most ominous factors determining prognosis are onset in the older child, epiphysial protrusion, extensive involvement of the epiphysis and arrest of subcapital growth. The overall prognosis is determined by the quality of preservation of the sphericity of the head, with maldevelopment leading to osteoarthritis. The aim of treatment is to achieve sphericity by containing the epiphysis within the acetabulum. A uniform regime of management cannot be recommended for all patients. Prolonged weight relief in containment appears to be the most satisfactory method of treatment in those with a pour prognosis. Operation is necessary to provide containment in the presence of ephiphyseal protrusion, and may also shorten the length of treatment in some younger patients. In the majority of young children the use of abduction braces which permit walking is recommended. In children with a minor degree of involvement a short period of bedrest may be all that is required. Overtreatment of young children should be avoided, as should undertreatment in the older age groups.