Abstract
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. 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. 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. 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.).
Highlights
Surgical indications for treatment of patients with LeggCalve-Perthes disease (LCPD) have been discussed previously by several authors [1,2,3]
In this study, we found that the epiphyseal slip-in index was a reliable indicator for predicting the effectiveness of a femoral varus osteotomy (FVO)
We focused on the image of the hip in a 40° abduction position during preoperative arthrography that had been performed under general anesthesia at the necrotic stage in 32 hips and at the regenerative stage in 6 hips, which simulated the post-operative relationship between the femoral head and the acetabulum
Summary
Surgical indications for treatment of patients with LeggCalve-Perthes disease (LCPD) have been discussed previously by several authors [1,2,3]. A femoral varus osteotomy (FVO) has become the most prevalent method for the surgical treatment [1, 3, 7,8,9] This has not always produced good results in past studies [10,11,12]. Reasons for such poor outcomes include an onset of more than 9 years, a Herring’s class C, an advanced stage of fragmentation at surgery, and pre-operative hinge abduction. These factors, except hinge abduction, could not always preclude a FVO.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
