Is an Active Lifestyle Really Best Recommendation for Patients with Asymptomatic DDH?

Commentary Dysplasia of the hip is a frequent cause of secondary osteoarthritis1,2. The Bernese periacetabular osteotomy (PAO) for treatment of developmental dysplasia of the hip (DDH) in adolescents and adults was introduced by Ganz in 19883. PAO has been proven to be an effective technique for the treatment of symptomatic DDH and can maintain the natural hip in appropriately selected patients for over 20 years4. In the past, authors focused mostly on radiographic parameters, patient age at the time of surgery, preoperative Merle d’Aubigné and Postel score, a positive anterior impingement test, a limp, an osteoarthrosis grade of >1, and a postoperative extrusion index of >20% as factors predicting a poor outcome of PAO for DDH3. However, surgeons have not been able to provide evidence-based recommendations to patients with regard to how they could protect their hip. Matheney et al. investigated activity level, body mass index (BMI), and the degree of hip dysplasia as predictors of symptoms and presentation for PAO by patients with DDH. The authors selected patients with DDH from a large institutional registry of patients being treated for DDH, femoroacetabular impingement, and mixed DDH/FAI. Despite the methods of data collection as well as the typical problems associated with following younger patients, only 48 of 756 patients were excluded because of an incomplete data set. The authors showed that an increased BMI, high level of physical activity, and high degree of dysplasia led to an earlier manifestation of symptoms and earlier operative treatment with a Bernese osteotomy. The combination of a high level of physical activity and a high degree of dysplasia was the most important risk factor. The findings imply that a decrease in physical activity could be recommended to delay the onset of symptoms and the need for surgical treatment in patients with DDH. This study offers surgeons new evidence on which to base their recommendations to their patients. The study had a few limitations. First, the authors used the University of California, Los Angeles (UCLA) score, which has been validated but does not include the frequency or duration of athletic activity as part of the score. Thus, the authors could only differentiate between occasional and regular activities. More detailed grading regarding the duration and intensity of physical activity associated with the development of symptoms in DDH would be useful. Second, a history of hip surgery was associated with a younger age at PAO; however, this group could not be analyzed in more detail because of the level of granularity of the data set. Previous studies have already shown that previous pelvic osteotomy leads to earlier failure of a subsequent PAO. This well-performed study documents the importance of multicenter databases for all diseases that affect a limited number of patients and of data collection for multiple factors influencing the prognosis. Even if such databases cannot answer every question, they offer valuable stimulation for future research possibilities.