Proximal Femoral Varus Osteotomy Performed in the Early Stage of Legg-Calvé-Perthes Disease Increases Femoral Head Revascularization: A Serial Perfusion MRI Study.

Lee, Joonoh; Mistry, Ahan; Kim, Harry K W · JB JS Open Access · 2026

retrospective_cohort · Level III

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Abstract

Legg-Calvé-Perthes disease (LCPD) is idiopathic osteonecrosis of the femoral head. The effects of proximal femoral varus osteotomy (PFVO) on femoral head revascularization are unknown. We evaluated whether patients with early-stage LCPD treated with PFVO had a higher revascularization rate than those receiving nonoperative treatment with serial perfusion magnetic resonance imaging (pMRI). Forty-nine patients (49 hips) in early-stage LCPD with ≥2 pMRIs treated nonoperatively (n = 22) or with PFVO (n = 27) were retrospectively analyzed. The mean age of diagnosis was 8.2 ± 1.7 years (range: 5.3-12.2), median pMRI of 3 (IQR:2-4; range: 2-6), and Waldenström stage I (n = 37) or IIa (n = 12). The revascularization rate (%/month) was assessed in 4-month intervals. Time to Waldenström stage IIIb and full weight-bearing status (FWB) were compared. Baseline characteristics (age, initial perfusion, Waldenström stage) were similar between groups. Perfusion was higher in the PFVO group at 4 to 8 (56 ± 20 vs. 80 ± 12%, p = 0.001) and 12 to 16 months (68 ± 25 vs. 91 ± 7%, p = 0.02) follow-ups. The PFVO group had significantly higher revascularization rates at 3 intervals: 4 to 8 (4.2 ± 2.7 vs. 7.0 ± 2.1%/month, p = 0.006), 8 to 12 (3.4 ± 1.7 vs. 6.1 ± 1.5%/month, p = 0.004), and 12 to 16 months (2.5 ± 1.3 vs. 4.9 ± 1.1%/month, p = 0.002). The PFVO group had a shorter time to Waldenström stage IIIb (22.7 ± 8.7 vs. 17.1 ± 6.9 months, p = 0.02) and was associated with earlier FWB (18.8 ± 6.5 vs. 13.1 ± 4.7 months, p = 0.008). The PFVO group had faster revascularization and a shorter time to the late-reossification stage. This study is the first to investigate the effects of PFVO on revascularization rate using serial pMRI. These findings provide novel insight into the biologic effect of PFVO on femoral head revascularization. Level IV, therapeutic. See Instructions for Authors for a complete description of levels of evidence.