Radiologic Outcomes of Bilateral and Unilateral Perthes Disease: A Comparative Cohort Study

Abstract

Introduction: This study was undertaken to compare the radiologic outcomes of bilateral and unilateral Perthes disease and also to evaluate the outcome of synchronous and metachronous bilateral Perthes disease. Methods: Of 353 children with Perthes disease followed up from presentation to healing during the last 10 years, 37 had bilateral involvement (11 synchronous and 26 metachronous onset). The radiologic outcomes of each hip of children with bilateral disease were compared with outcomes of 148 children with unilateral disease who were matched for age, sex, and treatment. Children with unilateral or bilateral diseases were treated with a proximal femoral varus derotation osteotomy if they fulfilled the criteria for surgery. The primary outcome measure was the shape of the femoral head at healing assessed by the Sphericity Deviation Score (SDS). Results: The children with bilateral disease were younger than those with unilateral disease (6.2 vs. 7.03 y; P < 0.001), and they had a longer duration of the disease. All other characteristics of bilateral and unilateral cases were similar. The SDS values of unilateral and bilateral disease were comparable, as were the SDS of synchronous and metachronous bilateral disease. The effect of early surgery on the evolution of the disease in bilateral cases was similar to that reported in unilateral disease. The age of onset of the disease alone influenced the SDS in bilateral cases. Conclusion:The age at onset of the bilateral disease is lower, the duration of the disease longer than that of unilateral disease, but the disease outcome is similar.

Legg-Calve´-Perthes disease - diagnostic value of acetabular-femoral head match index

“…The study by Singh 29 showed that patients with bilateral onset of LCPD had an earlier age of onset and a relatively longer course of disease than those with unilateral onset, but the prognosis was similar between the two groups. Our ndings similarly suggest that bilateral involvement is not an independent risk factor for at hips in LCPD.…”

Reliability of the Modified Method for Sphericity Deviation Score Using Only the Involved Hip Radiographs in the Patients With Legg-Calve-Perthes Disease

“…The setting criteria for reference points on the femoral head for SDS measurement have been described vaguely or inconsistently in previous studies. [4][5][6][7] When SDS was first introduced, the reference points were simply referred to as the medial and lateral margins of the femoral head. 4 However, it can be ambiguous in highly deformed femoral heads.…”

“…The sphericity deviation score (SDS) is a validated radiographic measure that quantifies the severity of femoral head deformity after the healed stage of LCPD, as a continuous numerical value 4 . The SDS is increasingly being used as a tool to measure the outcomes of LCPD, instead of the Stulberg classification, in more studies 5–7 …”

“…4 The SDS is increasingly being used as a tool to measure the outcomes of LCPD, instead of the Stulberg classification, in more studies. [5][6][7] The conventional method of SDS measurement requires the anteroposterior (AP) pelvis and frog-leg lateral radiographs covering both hips (ie, 2 AP pelvis views) to standardize the difference in radiographic magnification of the 2 views. This poses the issue of increased radiation exposure associated with 2 AP pelvis views in unilateral cases, and it also excludes patients who only had plain radiographs of the unilateral hip from research studies involving SDS measurements.…”