What is hip dysplasia?

Hip dysplasia may take various forms in the adult yet it always results from a change in the development and maturation of the infant hip. The problem is fundamentally an insufficient contact of the femoral head with the acetabulum cavity which leads to mechanical overload of the labrum and to the appearance of osteoarthritis if not treated at an early stage (fig.1 and video 1).

Fig. 1	In a normal hip there is a homogeneous distribution of static contact strains on the ceiling of acetabulum	In dysplasia strains accumulate at the lateral margin with overload of cartilage, hypertrophy of the labrum and loss of articular concentricity	If this situation is not corrected it leads to the upper and lateral migration of the femoral head with formation of arthritis

Typically the hip dysplastic has no symptoms during the teenage years, unless it is very severe. The first symptoms may appear in the second or third decade of life and may initially be very mild. The first symptom may be pain in the lateral region of the hip and groin. Symptoms of stuck leg and feeling that the hip is going to dislocate will appear typically at a later stage, when there are already major lesions to the cartilage or labrum. Many patients with dysplasia experience enhanced mobility of the hip since the acetabular cavity is smaller than normal (fig. 2).
 

In the normal hip the femoral head should be covered by the acetabulum and this should be centered like a hat on the head	In the dysplastic hip the femoral head is less covered and the acetabulum tilted the hat leaves a part of head uncovered.