Arthrographic indicators for decision making about femoral varus osteotomy in Legg-Calvé-Perthes disease

Abstract

Purpose There is not always a good outcome after a femoral varus osteotomy (FVO) in those with Legg-Calvé-Perthes disease (LCPD), even when the severity warrants surgical treatment. The purpose of this study was to find arthrographic indicators for decision making regarding the likely surgical outcome of a FVO. Methods We used an image of an abduction position during preoperative arthrography under general anesthesia that simulated the post-operative relationship between the femoral head and the acetabulum. In the image, we defined two indicators of how deeply the deformed epiphysis was contained within the acetabulum: an acetabular head index in abduction and an epiphyseal slip-in index. Finding the contact point between the top of epiphysis and acetabulum was the key for the epiphyseal slip-in index measurement. In 37 patients (38 hips) who underwent FVOs based on our inclusion criteria, these two indices were measured retrospectively and were analyzed for a correlation with surgical outcome. Surgical outcome was evaluated using a combination of three factors: sphericity of the femoral head (Stulberg's classification), acetabular cover (acetabular head index), and the slope of acetabular roof. Results The outcome was acceptable in 20 hips (52.6%) and unacceptable in18 hips (47.4%). There was a statistically significance difference in epiphyseal slip-in index between the acceptable group (21.9 ± 2.8%) and the unacceptable group (15.0 ± 4.4%) (P \ 0.0001). An index of 20% or more determined a safe zone for predicting an acceptable outcome with 80% sensitivity, 89% specificity, and a 7.2 likelihood ratio. However, the acetabular head index in abduction showed no such statistical significance. Conclusions In this study, we found that the epiphyseal slip-in index was a reliable indicator for predicting the effectiveness of a FVO. It is worth measuring this index when a surgeon is considering a FVO for a patient with severe LCPD. (Level of Evidence Level III.)

LCP hastalığının tedavisinde varus osteotomisinin yeri ve etkinliği; güncel değerlendirme

“…Epifizyel slip-in endeksi, bu açıdan kullanılabilecek bir parametre olarak öne sürülmüştür. [24] Femoral varus osteotomisinin sonucunda bazı komplikasyonlar görülebilir. Bunlar arasında; aşırı miktarda varus verilmiş olması en önde gelmekle birlikte, varusun yeniden şekillenmesinin yeteri kadar olmaması, rotasyonel osteotomi sonrası hastada eksternal rotasyon deformitesinin sebat etmesi, ekstremitenin kısalması, abduktor topallaması, trokanterik aşırı bü-yüme, tespit materyalinin (plak) çıkarılma gerekliliği, plağı çıkardıktan sonra kırık oluşması, gecikmiş kaynama ya da kaynamama olması ihtimalleri sayılabilir.…”

Arthrogram in Legg-Calvé-Perthes Disease

“…12 However, conventional radiography does not give us information on these 2 factors. 15,[20][21][22] Therefore, it becomes necessary to resort to other examinations, such as pneumoarthrography (PAG) and magnetic resonance imaging (MRI), to evaluate the optimal treatment with greater certainty. 7,13,[23][24][25][26] Copyright r 2011 by Lippincott Williams & Wilkins…”