Evolution of Legg-Calvé-Perthes disease following proximal femoral varus osteotomy performed in the avascular necrosis stage: A prospective study

Abstract

Purpose This prospective study was undertaken to describe patterns of fragmentation of the femoral epiphysis following a proximal femoral varus osteotomy (PFVO) done during stage I of LCPD and to assess the disease duration and outcome in each pattern. Methods A total of 25 children treated by a PFVO in stage I of LCPD were followed until healing. The MRI Perfusion Index, radiographic changes in the femoral epiphysis, disease duration and the Sphericity Deviation Score (SDS) at healing were documented. The reproducibility of classification of the pattern of fragmentation, estimation of disease duration and SDS were assessed. The duration of the disease and SDS in the patterns of fragmentation were compared. Results Four patterns of fragmentation were noted, namely, typical fragmentation, bypassing fragmentation, abortive fragmentation and atypical fragmentation with horizontal fissuring. The reproducibility of classifying the pattern of fragmentation was moderate (Kappa: 0.48) while the reproducibility of other continuous variables was excellent. The Perfusion Index was less than 50% in every affected hip. The duration of the disease and SDS were lowest in children in whom the stage of fragmentation was bypassed but these differences were not statistically significant. Conclusion Following a proximal femoral osteotomy during stage I of LCPD the fragmentation stage may be bypassed partially or completely and the chances of a good outcome appear to be very good if fragmentation is bypassed. Level of Evidence Level II Prognostic Study

Bypass of Epiphyseal Fragmentation Following Early Salter Innominate Osteotomy and Its Clinical Relevance in Legg-Calvé-Perthes Disease

“…The percentages of 2 patterns of typical fragmentation and atypical fragmentation with horizontal fissure appreciably differed between hips treated with SIO and FVO, with the former being higher in this study (67% vs. 5%) and the latter being higher in a previous study (48% vs. 16%). 9 Whether this discrepancy relates to only different osteotomy sites warrants further investigation by use of other cohorts treated with early SIO. Besides the impact on the amount of blood flow, these 2 osteotomies differ in terms of the load vector-altering effect for the capital femoral epiphysis.…”

“…Second, because of the retrospective nature of the study, the intervals between serial radiographs were not standardized, probably leading to a greater overestimation of the actual stage duration than other prospective studies. 8,9 All school-aged patients, however, were examined every long holiday twice or 3 times a year until skeletal maturity, and patients and their parents were usually requested to visit 1 or 2 more times during the school day until implant removal. This examination schedule corresponds to 3 or 4-month intervals during the active stage of the disease and afterward at least 6 months intervals, being comparable with that of other prospective studies.…”

“…Nonetheless, uncertainty exists as to whether the observed abortive bypassing is because of the effects of early containment surgery itself or the preserved vascularization of the femoral head. Second, because of the retrospective nature of the study, the intervals between serial radiographs were not standardized, probably leading to a greater overestimation of the actual stage duration than other prospective studies 8,9. All school-aged patients, however, were examined every long holiday twice or 3 times a year until skeletal maturity, and patients and their parents were usually requested to visit 1 or 2 more times during the school day until implant removal.…”

Prolonged non-weightbearing treatment decreases femoral head deformity compared to symptomatic treatment in the initial stage of Legg–Calvé–Perthes disease

“…This finding is echoed in the recent publication by Singh et al . [28], who suggested that an extended period of weight-relief after proximal femoral varus osteotomy may help prevent fragmentation and collapse of the epiphysis and thus preserve the recanalization vessels previously described by Conway [29] as being predictive of a good outcome. Previous investigations into the pathogenesis of femoral head deformity using a piglet model of ischemic osteonecrosis [4,5] demonstrated decreased mechanical strength of the femoral head due to increased bone resorption and decreased bone formation during the repair phase of the model, which resembles the fragmentation stage of LCPD.…”

Repeated Pelvic Radiographs in Infants, After Harness Treatment for Developmental Dysplasia of the Hip, Carry Very Low Radiation Risk

“…Within paediatric orthopaedics, numerous conditions encompass follow-up which involves radiographic imaging. The risk associated with routine follow-up of patients with Perthes Disease or hip surveillance in Cerebral Palsy is ground for future research [ 30 , 31 ] . Whilst radiographs are so important for complete assessment, this study supports that the radiation principles ‘As Low As Reasonable Achievable (ALARA)’ are being adhered to for DDH follow-up [ 32 ].…”