The Remodeling Of The Proximal Femur And Acetabulum After Subtrochanteric Varus Osteotomy For The Treatment Of Legg-Calve-Perthes Disease

ObjectiveWe reviewed the radiographs and clinical information of children, who wereunderwent subtrochanteric varus osteotomy for Perthes disease. The aim of the study wasto observe the structural changes that occur in the proximal femur and theacetabulum aftersubtrochanteric varus osteotomy.To stratified analysis the influence of the operation toremodeling，images efficacy and hip Joint function by Lateral pillar types.MethodsWe reviewed the radiographs of the43children with perthes disease,18patients ofwhich had been treated by conservative treatment, whereas25had been teated bysubtrochanteric varus osteotomy. The mean age at operation was6.6years(range,2to11years), Patient follow-up ranged from2to7years,average4.3years. The average age ofconservative treatment was from4to12years, average6.8years. Patient follow-up rangedfrom2to11years,average4.8years. We collected the clinical data and radiographs ofPelvis AP and frog leg position,at preoperative,postoperative,and final follow-up. Wemeasured the changes of articulotrochanteric distance (ATD), neck-shaft angle, acetabularindex (AI), the ACM angle, epiphyseal index (EI), head and neck index (HNI),acetabular-head index (AHI) and femur head sphericity from preoperative until the time offinal follow-up,to analyse the remodeling of the proximal femur and acetabulum aftersubtrochanteric varus osteotomy for the treatment of Perthes disease. Moreover,we identifythe correlation between Herring lateral pillar classification, neck shaft angle atpostoperative and Stulberg classification or Mose`s index,and Stratified analysis theinfluence of the operation to remodeling and hip Joint function by Lateral pillar types.ResultsFrom postoperative to the end of follow-up AHI and neck-shaft angle were all increased, the average increased8.4°, neck-shaft angle average recovery to92.52%of theoriginal angle. ATD values, AI, ACM, EI, and HNI in the follow-up period had nosignificant changes. Lateral pillar classification has a significant correlation to the Stulbergclassification and Mose`s index. Stulberg classification of the surgical group, the excellentand good result in Lateral pillarB group was100%, in group C was41.7%，the totalexcellent and good result was72%. Stulberg classification of the conservative treatmentgroup, the excellent and good result in Lateral pillar B group was83.2%, in group C was50.0%, the total excellent and good result was72.2%. There was no statistically signifcantdiference between the groups in terms of Stulberg classifcation stratified analysis by MannWhitney test. In operation group,the postoperative neck-shaft angle of Stulbergclassification excellent was113.23±4.80°, the postoperative neck-shaft angle of Stulbergclassification good was112.2±3.90°, the postoperative neck-shaft angle of Stulbergclassification poor was121.43±4.39°. There was a significant correlation betweenHerring lateral pillar type and the Mose index at the end of follow-up. Mose index of thesurgery group，the excellent and good result in Lateral pillar B group was100%, in groupC was25.0%, the total excellent and good result was64%. Mose index of the conservativegroup，the excellent and good result in Lateral pillar B group was75%, in group C was25.0%, the total excellent and good result was61.1%. Statistical analysis showed thatresult of the femoral head sphericity of Lateral pillar B patients in the surgical group wasbetter than the conservative treatment group, B/C and C no significant differences. Therewas no statistically significant diference in Harris hip score and the leg-length discrepancybetween subtrochanteric varus osteotomy and conservative treatment. Lateral pillarB and Cpatients were stratified analysis, there was no statistically significant diference in Harriship score and the leg-length discrepancy between subtrochanteric varus osteotomy andconservative treatment.Conclusion1. Proximal femoral varus osteotomy can significantly improve femur head sphericityand femoral neck shaft angle remodeling,but It was not significant to the acetabular andgreater trochanter remodeling.2. Lateral pillar type is a important prognostic factor in Perthes disease.3. The neck-shaft angle of postoperative is not the greater the better. Neck-shaft angleis more appropriate to maintain110°to115°,when performing subtrochanteric varusosteotomy.4. There was no statistically significant diference in Harris hip score and the leg-length discrepancy between subtrochanteric varus osteotomy and conservativetreatment.