Assessment of adult hip dysplasia and the outcome of surgical treatment.

Hip dysplasia and hip joint deformities in general are recognized as possible precursors of osteoarthritic development. Early and correct identification of hip dysplasia is important in order to offer timely joint preserving treatment. In the contemporary literature, several controversies exist, and some of these were the focus of this doctoral thesis. Categorized into subjects, the major findings and their possible importance are listed below. DIAGNOSTIC ASSESSMENT OF HIP DYSPLASIA: A multi-observer study quantified the variability of different methods for diagnostic assessment of hip dysplasia and osteoarthritis and resulted in general recommendations regarding diagnostic assessment of hip dysplasia. Pelvic tilt was shown to differ significantly between the supine and weight-bearing positions in patients with dysplastic hip joints. This is a finding that adds controversy to the application of neutral pelvic positioning during assessment of hip deformities because pelvic tilt affects the appearance of acetabular version. Weight-bearing assessment of acetabular version showed the presence of retroversion in 33% of dysplastic hips. The establishment of retroversion as a rather frequent entity in dysplastic hips is contradictory to the historical finding that hip dysplasia is characterized by insufficient anterior and lateral coverage. In general, the findings have important implications for orthopedic surgeons and radiologists dealing with diagnostic assessment of painful hips in young adults, and for surgeons planning and performing joint-preserving periacetabular osteotomies. ASSESSMENT OF ACETABULAR LABRAL TEARS IN HIP DYSPLASIA: The roles of ultrasound and clinical tests in acetabular labral tear diagnostics were established. After overcoming an initial learning curve, ultrasound investigation was highly reliable in diagnosing labral tears, whereas only a positive impingement or FABER test was reliable in identifying a labral tear. It seems that non-invasive and rapid ultrasound examination performed by an experienced examiner can potentially alter the traditional diagnostic algorithm in which magnetic resonance arthrography remains the gold standard. PERIACETABULAR OSTEOTOMY FOR SURGICAL TREATMENT OF HIP DYSPLASIA IN ADULTS: Encouraging hip joint survival and clinical outcome were reported at medium-term follow-up after periacetabular osteotomy. The small number of studies reporting the outcome beyond a 5-year follow-up is in contrast to the wide application of the periacetabular osteotomy. The performed analysis of predictors of conversion to total hip replacement following periacetabular osteotomy documented the importance of different biomechanical and degenerative factors. Knowledge about factors predicting early conversion to total hip replacement has the potential to refine patient selection and to improve treatment by periacetabular osteotomy. Cartilage thickness was documented to be preserved up to 2,5 years after periacetabular osteotomy. All but 1 hip joint had acetabular labral tears, thus indicating that the presence of labral tears does not accelerate cartilage degeneration after periacetabular osteotomy.