Monday, January 31, 2011

Hip examination from the perspective of an osteopath

In order to diagnose back pain the osteopath needs to be aware of the contribution of the hip joint. The hip has a unique structure carefully designed to fulfill its functions in the body.

The hip has two main functions; mobility, propelling the leg forward, and stability, linking the lower limb to the torsoe. Unlike other bones in the body, the head of the femur is attached to its shaft via a neck. This system of levers allows increased range of movement and less muscular effort, however, it also increases the joint's vulnerability.

Hip stability is the result a multitude of structures such as the head of the femur sitting in a deep pelvic acetabulum reenforced by the acetabular labrum and strong ligaments (pubo, ischio and illio-femoral ligaments). It has a good nerve supply, the obturator nerve (L2, L3, L4), which supplies the hip capsule and serves to convey proprioceptive information to the brain about hip position. Multiple arteries, the circumflex artery and ligamentum teres provide the necessary nutrients. However, disturbence of the blood supply ultimately results in avascular necrosis of the bone, degeneration and osteoarthritis. Ironically it is the strong ligaments that surround the neck of the femur that can compromise the security of the hip by compressing its blood supply.

Conditions that affect the hip joint as a result of poor blood supply are Perthes disease and slipped femoral ephiphysis. Patients with a history of these conditions or congenital hip displacement may turn up at an osteopthic clinic many years later complaining of low back pain.

A fixed flexion deformity of the hip due to osteoarthritis is the result of contraction of the muscles surrounding the hip joint (the strong external rotators and adductor magnus), in an attempt to stabilize the joint. The body compensates for reduced hip extension by extending the lumber spine beyond its normal range leading to stress on the soft tissues of the lumber spine or compression of the facet joints leading to back pain. Other causes of back pain may be the result of referred pain from the hip's nerve supply (obturator nerve). Finally, contraction of the muscles around the hip joint such as gluteus minimus or medius may be mistaken for back pain.

The osteopath should be aware of hip invlovement when assessing back pain. As well as using the standard orthopedic tests, Trendelenberg's sign and Thomas's test the osteopath has the added skill of palpation of the hip joint to assess quality of movement and decide whether there is any shortening of the soft tissues or arthritic changes.

Video demonstrating passive hip examination.
Click here for more info on arthritis and osteopathy
or here for more info in Hebrew