In this important paper by Larson, Sucato, Herring et al., the authors have studied a subset of patients from the Texas Scottish Rite Hospital who had participated in a prospective multicenter study of Legg-Calvé-Perthes (LCP) disease1, focusing on long-term follow-up of patients who received little or no treatment. Their goal was to determine the functional and radiographic outcome twenty years after treatment.
LCP disease remains one of the most challenging conditions presenting to pediatric orthopaedic surgeons. The goal of treatment includes maintaining hip motion and joint sphericity, by containing the femoral head within the acetabulum during its biologically plastic phase, to provide the best chance for joint remodeling as well as to minimize the risk of premature hip arthritis. However, the best treatment methods for achieving this goal remain elusive. The continuing skepticism regarding treatment efficacy allowed inclusion of a minimal nontreatment cohort in the Texas prospective trial, providing the patients available for the current long-term follow-up study.
Classic teaching regarding the outcome of LCP disease, based on long-term studies by Gower and Johnston2, Stulberg et al.3, and McAndrew and Weinstein4 from the University of Iowa, has been that most patients with LCP disease do well until the fifth or sixth decade of life before experiencing a decline in their hip function.
Most of the Iowa patients had little formal treatment and were thus similar to those evaluated in the current paper. These earlier studies showed that a typical patient with LCP disease could live comfortably until forty to fifty years of age and then would likely require total hip replacement.
The Texas study suggests an entirely different long-term prognosis. At an average of twenty years of follow-up, more than half of the patients had signs of impingement on examination, 76% had intermittent hip pain, almost 40% complained of hip pain at least several times weekly, and 7% had undergone a reconstructive procedure. Validated outcome measures revealed that only about 50% of the patients had good to excellent clinical and radiographic results at twenty-two to thirty-five years of age, a period in life when one expects excellent musculoskeletal function.
Several factors should be considered in evaluating the current report, which shows a poor outcome for LCP disease over time compared with earlier studies. It should be noted that only slightly over half of the patients in the nonoperatively treated cohort returned for follow-up. It is possible that the many who did not return had better results.
Also, this follow-up study was performed in a new era that includes a much clearer understanding of the concept of hip impingement and how anterolateral femoral head prominence causes impingement and acetabular degeneration. The Iowa patients may have had similar symptoms and radiographic findings but may have been told that these were less important.
The current Texas data were interpreted within an era of increased availability of proposed surgical procedures to correct hip impingement and asymmetry. Following the work of Ganz et al. in Bern, Switzerland5, the orthopaedic surgeons involved in the current study and at many other centers began to rigorously question patients who had prior LCP disease regarding symptoms and to perform physical examination tests (in particular, the impingement test) that would confirm any symptoms. Much has been learned regarding radiographic changes in patients with LCP disease, and the radiographs in the current study may have been graded more strictly than those in an earlier era.
The much higher prevalence of obesity in modern young adults compared with those in the 1960s and 1970s could also be a factor in causing the current patients to have greater hip dysfunction. As the authors of the current study note, the modern urban, athletically driven culture leads to greater expectations for high-level musculoskeletal function compared with the expectations of patients from a prior, more rural era. It is entirely possible that, if the 1960s Iowa patient cohort could somehow have been magically called in to Dallas in 2010 for a critical analysis, they too might not have been thought to be doing very well at twenty years of follow-up.
Although only a few patients in the current study have had further hip surgery, the results of this report will likely support the trend toward so-called “hip preservation surgery” that includes femoral head-neck recontouring, labral repair, and late acetabuloplasty. As yet, there are no data to document that such surgery will improve the natural history of LCP disease.
In summary, the treatment of LCP disease remains in flux. Modern expectations for high-level hip function into mid-adulthood, even in patients who have had substantial childhood hip disease, will continue as individuals place greater athletic and work demands on their hips. The current study suggests that, considering the demands of modern patients, the rather cheery outlook noted in the past for nonoperatively treated patients with LCP disease no longer applies. This study will further encourage the current trend in the treatment of LCP disease, which includes more aggressive containment treatment for younger children and “hip preservation surgery” for teenagers and young adults with continuing symptoms. Whether this pattern will be a wise one remains unanswered.