Research advances on borderline developmental dysplasia of the hip / 中华骨科杂志

ABSTRACT

BDDH (borderline developmental dysplasia of the hip) or BHD (borderline hip dysplasia) is a disease with more controversies in the following aspects, including definition, diagnosis and interventions. The proportion of radiographic BDDH is 3.5 times that of developmental dysplasia of the hip (DDH) in the asymptomatic general population, and can exceed 40% in specific cohorts including female collegiate athletes. Up till now, researchers have not reached a consensus on its definition. The diagnosis depends largely on personal history, physical examinations and radiographic examination. The interventions, including non-operative approaches, hip arthroscopy and periacetabular osteotomy, are used. Inappropriate treatment may exacerbate symptoms and accelerate hip joint degeneration. Recent studies on BDDH with regard to its definition, diagnosis and interventions were reviewed. Lateral centre-edge angle (LCEA) measured on AP pelvis was crucial but not enough in defining BDDH, for it only reflects lateral coverage of the hip while anterior and posterior coverage may vary dramatically. Given that hips with an LCEA less than 20 degrees associated with developing osteoarthritis, we recommended that LCEA between 20 to 25 degrees be used as the radiographic criterion in the primary screening. Further evaluation of symptoms and physical examinations should be follow to identify hip instability and/or impingement. Periacetabular osteotomy must be indicated for hips with predominant instability and it can be performed with or without hip arthroscopy which is aimed to address labral lesion or cam deformity on the femoral side. Hip arthroscopy is indicated for hip with predominant impingement symptoms. However, there is no consensus on the outcomes of the two procedures currently. Further studies are still required to confirm long-term results. Thus, it is imperative to choose the right indications for each procedure.