The abductors are muscles which arise from the outer side of the pelvis and converge in tendons down onto the upper end of the thigh bone or greater trochanter. When the muscle contracts, tension is applied to the tendon and the upper end of the thigh bone is pulled upwards. This, in turn, has the effect of taking the lower limb out to the side. This is the movement called abduction. The converse would be taking the upper limb across the midline of the body towards the other side. That would be called adduction. Flexion is where we pull the thigh bone forwards and extension is when the thigh bone is taken backwards. Rotation speaks for itself. Internal rotation is towards the other side whereas external rotation is towards the outside.
Abductor dysfunction can present in a number of manners.
The most common is in the form of an inflammatory process or degenerative change within the tendons that insert into the upper end of the thigh bone or the greater trochanter. We calls this abductor tendinopathy. Sometimes partial or complete tears can occur. The region over the greater trochanter can become painful. A secondary bursitis often forms.
Another type of abductor dysfunction occurs when the abductor muscles themselves are weak or even paralysed. The normal pattern of gait is no longer possible. Instead, the patient must tilt his or her torso over the top of that hip whilst load bearing on that limb. This is the so-called abductor or Trendelenburg lurch.
Not all forms of abductor dysfunction are associated with pain but they do often give rise to ambulatory incapacity. Their diagnosis requires the gleaning of a thorough history, the performing of a complete examination and ancillary investigations including plane radiographs and an MRI scan.
Treatment modalities can be of a non-operative nature and include physiotherapy and muscle exercises in the gym environment, the local installation of hydrocortisone and local anaesthetic, or even the use of splints or supporting devices.
Operative options can include repair of ruptured tendons, the excision of an inflamed bursa, or even reconstruction of the mechanism using artificial material such as meshes and tapes.