What is Hip Instability?
Hip instability may be divided into two types: traumatic or atrumatic. The diagnosis is made based on history, physical examination, and imaging studies. Imaging studies that may be performed include plain xrays, CT scans, MRI, and MRI arthrography. Physical examination studies include tests for generalized ligamentous laxity (e.g. Brighton criteria) and the hip dial test.
Nonsurgical Treatments for Hip Instability
Nonsurgical treatment consists primarily of rest and physical therapy, with an emphasis on isometric strengthening of the muscle groups around the hip.
Surgical Treatments for Hip Instability
Surgical treatment may be performed acutely in overt traumatic injuries when there is an associated fracture, or when there are loose bodies of bone and/or cartilage in the joint. Most of these fractures are treated with open surgery and plates and screws. Seldomly, acetabular fractures may be treated with arthroscopic assistance.
The photo above features an arthroscopic view of a capsular plication. The sutures are tied to tighten the joint capsule.
In contrast to traumatic hip instability which occurs with a specific event or injury, atraumatic hip instability occurs in the chronic setting. Collagen disorders, such as Ehlers-Danlos disease, may be identified in rare cases.
Other causes of chronic instability include rotational instability in athletes and dancers, particularly those in which extremes of range of motion of the hip are performed repetitively.
Instability of the hip may also be contributed by hip dysplasia, in which a relative decrease in the bone coverage of the hip joint contributes to abnormal motion of the joint.
True hip dislocations are extremely rare in these patients, and most patients complain of pain, snapping hips, and gait abnormalities. Surgical treatment of chronic instability oftentimes may be performed through hip arthroscopy, and consists of a tightening, or capsular plication with sutures, of the capsule and ligaments of the hip joint. The iliopsoas tendon and ligamentum teres act as dynamic stabilizers of the hip joint and may be affected by instability.