Hip Dysplasia (DDH)
Dysplasia is a condition in which the acetabulum (hip socket) does not develop symmetrically with the femoral head (or ball), usually resulting in insufficient coverage of the ball by the socket. Stresses on the cartilage that lines the socket are then too high and result in problems such as labral tears, degeneration of cartilage and, ultimately, arthritis of the hip.
Approximately 40% of hip replacements are performed because of arthritis secondary to the long term effects of hip dysplasia.
Dysplasia can occur at birth (congenital dislocation of the hip, or CDH) or may develop during growth and development (developmental dysplasia or the hip, or DDH). The condition is genetically inherited but the DNA abnormalities have not yet been uncovered. Common symptoms include but are not limited to: pain, limp, arthritis, leg length inequality and malrotation.
It is not uncommon for patients to receive incorrect diagnoses such as 'groin strain', 'muscle pull', 'tendonitis', 'overuse syndrome' and 'bursitis', among others, for years before the correct diagnosis is established.
There are many possible surgical approaches to treat hip dysplasia. All have in common the goals of relief of pain, restoration of normal function and postponement of the time frame for a total hip replacement. It remains to be proven if the surgical interventions put off the time for hip replacement, as it is very difficult to perform prospective, randomized trials between surgically treated and non-surgically treated patients. Patients who are in pain are reluctant to agree to randomization into groups that get physical therapy alone. Periacetabular osteotomy (PAO) has emerged as the main hip preservation procedure for surgical treatment of DDH. There is also a role for intertrochanteric osteotomy (ITO) in cases of malrotation, leg length inequality and femoral deformity.