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Up-date on proximal femoral osteotomy in the treatment of Legg-Calve-Perthes disease

INTRODUCTION Legg-Calvé-Perthes disease (LCPD) is an idiopathic hip disorder that produces ischemic necrosis of the growing femoral head with subsequent bony collapse and femoral head permanent deformity1. The natural history of the LCPD and its radiographic course are very well described2. Aim of the treatment is a spherical femoral head and hip joint congruency that last for the most of patient’s adult life. The late outcome is good or very good in more than 80% of LCPD hips and persisted into the fourth decade of life. However, more than 50% of patients develop disabling osteoarthritis in the sixth decade of life3, Although without today’s popular classification systems (Catterall, Herring pillar system)2, 4, Anatol Axer published in the year 1965 preliminary report and proposed femoral varus derotation osteotomy (FVO) as an alternative method for treatment of LCPD5. The optimum surgical treatment of patients with LCPD is debatable7, 8. With idea of using plasticity potential of the femoral head in fragmentation and re- ossification phase, Axer proposed treatment aimed to removal of the protruded flattened and damaged ostechondral head segment from the damaging influence of the lateral acetabular lip. This containment principle had two main goals to achieve with FVO 1. reduction of mechanical stress by restoring of the central position of the femoral head ; 2. preservation of the joint congruence. Ultimate goal was to postpone, as far as possible, late osteoarthritis of the hip joint. CURRENT CONCEPTS Joseph et al. studied sequential radiographs of 148 patients (out of 314) treated with FVO9 Patients' age < 12 years, Boys 8, 0 y. (+/-2) Girls 7, 7 y. (+/-1, 9). Control group were 323 patients treated only symptomatically to relieve pain. Catterall, Herring and modified Elizabethtown classification were utilized. Minimum follow-up was 2 years. Results indicated that FVO alters natural history in older children ; bypassing fragmentation stage in early stage surgery, reducing fragmentation stage, minimizing extrusion of femoral head, reducing metaphyseal widening, retaining the sphericity of the femoral head in a large proportion of children9. Kim HKW et al. studied 52 patients treated with FVO10. All patients were 16, 5 y. (+/-2, 0) with follow-up to the skeletal maturity10. Neck-shaft angle: 1380 +/- 70 pre-op ; 1150 +/- 110 post-op ; 1240 +/- 80 final. Recommendation is 100 to 150 varus correction when performing FVO. FVO may work in combination 1) alteration in hip biomechanics, 2) increased blood flow to the region, 3) forced rest and activity modification induced by the surgery. Other factors, e.g. growth disturbances of the proximal femoral physis and femoral head collapse also contribute to articular-trochanteric distance. Friedlander and Weiner studied 116 patient treated with FVO11. All patients in Herring group B and C. F/up 6 y. 9 m. (range 3 to 15 y.). Outcome evaluated by radiographic Stulberg class12. Results indicated that patients in Herring B and younger than 9 years were 86% in Stulberg class I and II. Patients in Herring B of age 9 years and older were 67% in Stulberg class I and II. Patients in Herring C and younger than 9 years 43% were in Stulberg I and II. Patients Herring C of age 9 years and older 30% were in Stulberg I and II.11 Aksoy et al. studied 24 patients and 26 hips with LCPD13. Outcome was measured with Stulberg classification12. The mean age: 8, 3 years ; the mean follow-up was13 years. All patients were mature at follow-up. All patients were older than 6 years and had lateral pillar group C hips. Results indicated that at final follow-up were 6 hips in Stulberg I and II ; 19 hips in Stulberg III and IV and one hip in Stulberg V. Six out of 14 hips treated before 9 years healed with spherical congruency. All hips after 9 years healed with Stulberg III, IV and V. Trochanteric overgrowth was evident in 20 hips. Authors concluded that FVO treatment in Herring class C hips had a poor outcome, after 9 years of age13. Noonan at al. studied FVO in 17 patients older than 9 years of age with 18 hips14. There were 17 hips in Catterall 3 and 4. Four hips had partial or complete loss of lateral pillar. Average follow-up was 10 years (range 4, 2 – 17, 8). Results indicated Stulberg I = 3 hips ; Stulberg II = 3 hips ; Stulberg III = 4 hips ; Stulberg IV and V = 8 hips. FVO improves results in children older than 9 years compared with natural history studies or studies of non- containment methods14. Terjesen et al. studied 70 patients older than 6 years of age with femoral head necrosis > 50%, treated with FVO15. Catterall classification was utilized15. Follow-up was 5 years. Control group consisted of 51 similar children treated with physiotherapy. Femoral head radiographic outcome was graded as spherical, ovoid and flat. In patients with Catterall group 3, there was no difference in outcome. In patients with Catterall group 4, sphericity of femoral head was better in FVO. Flat head was found in 14%, only. In with physiotherapy group were 75% patients with flat head in15. FUTURE TREATMENTS Previous studies have fertilized ground for future research in the field of the best possible treatment for patients with LCPD. As usual, in future, we need more strict inclusion criteria and prospective studies with more patients. It seems that surgical treatment in LCPD should be more age and grouping dependant, than it was in the past. CONCLUSION As result of this overview and personal experience there is strong indication that femoral osteotomy could improve outcome in patients older than six years and younger than nine of age. Patients in Catteral group of 4 and in Herring class B could have significant improvement in sphericity and containment at maturity. Femoral varus osteotomy should stay in surgeons’ armamentarium for treatment of patients with LCPD.

Legg-Calve-Perthes disease ; proximal femoral osteotomy ; Up-date

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