Chapter 40 Legg-Calve-Perthes Disease: How Should It Be Treated?
The necessity for evidenced-based investigation is nowhere better illustrated than in the case of the treatment of Legg–Calve–Perthes disease. In the United States, as well as around the world, an amazing variety of treatment methods are used for this condition. These vary from long-term relief from weight bearing, to months and months of abduction cast treatment, to combined femoral and pelvic surgical procedures, to ignoring the disease altogether. Even more striking is the degree with which orthopedists defend their chosen method.
Some years ago, I critically reviewed the literature up to 1994.1 Although much has been written since that date, some principles of importance came out of that review that apply specifically to Legg–Perthes disease.
STUDIES THAT REACH LEVEL I OR II
In 1993, Fulford, Lunn, and Macnicol’s2 comparison of 2 groups of patients randomized by source of referral was published. The children treated at Royal Hospital for Sick Children were compared with those treated at the Princess Margaret Rose Orthopaedic hospital. The children at the first hospital were treated with an ischial-bearing patten-ended caliper. Those at the second hospital had a varus, derotational proximal femoral osteotomy. This study can be considered a controlled, prospective study. The authors identified no differences in outcome between the groups. Outcome in their study was found to correlate with femoral head shape at presentation and the age at onset. They note that of the heads with severe deformity at the initial arthrogram, only 4 of 25 hips improved to have a good result, and all were younger than 5 years at onset. Two of these patients were receiving brace therapy, and two had surgery. Compared with historical control subjects, the authors believe that both methods are effective. Because of the wide variation in reporting of historical control subjects, I do not believe that such comparisons are useful in this disorder.
Harrison and Bassett3 performed a double-blind trial of pulsed electromagnetic field treatment in patients also being treated with a non–weight-bearing Birmingham orthosis. This study shows no discernible effect of the electromagnetic field treatment. The effectiveness of the orthosis was not elucidated by this study because the study did not include a control or comparative group.
Herring and colleagues4 report on the results of a long-term, controlled study performed by the Legg Perthes Study Group. Thirty-nine pediatric orthopedists from North America and New Zealand agreed to a “best-effort” study in lieu of randomization. In this paradigm, each surgeon agreed to apply a single treatment method to each patient who met the study criteria. The presumption of this type of study is that so large a sample will likely override local selection factors and provide comparable treatment groups. The treatment groups were no treatment, range of motion treatment in which the patient did exercises once a day, Atlanta brace treatment, femoral varus osteotomy, and Salter innominate osteotomy. Within each treatment group, except the no treatment group, Petrie casts could be used up to two times to overcome hip stiffness.
Part one of the study provides detailed classifications that were tested in interobserver and intraobserver trials that showed good reliability5. The classifications evaluated were the lateral pillar classification in the early stages of disease and the Stulberg classification at skeletal maturity. The outcomes were analyzed relative to age at onset and severity of disease. Patients were managed to skeletal maturity and assessed independently by an observer not involved in patient treatment.