LEFT HIP PAIN
A 67-year-old woman comes to see you in the orthopaedic outpatient clinic complaining of left groin pain. The pain has been present for the last 12 months and has become progressively worse. It initially responded to ibuprofen and paracetamol, but now the pain is keeping her awake at night. Over a similar time period there has been a reduction in mobility and she now uses a stick when going outside. There has been no history of injury and there are no neurological symptoms. She underwent a mastectomy for breast cancer 15 years ago. She takes tamoxifen and omeprazole.
She is overweight with a body mass index (BMI) of 31. She walks with an antalgic gait and has a positive Trendelenberg test. There is no gross deformity of the lower limbs and the real leg lengths are equal. There is a restriction of all her left hip movements, especially internal and external rotation. Her back and knee examinations are unremarkable.
Her pedal pulses are palpable and the sensation in the leg is normal.
This woman has primary osteoarthritis of her left hip. There is a reduction in joint space and periarticular sclerosis seen in the left hip joint.Primary osteoarthritis is by far the most common cause of joint degeneration. Less common is secondary osteoarthritis where there are a variety of different causative factors including developmental (congenital) dislocation of the hip, slipped upper femoral epiphysis, osteonecrosis and trauma.
Patients typically present with pain felt in the groin that may radiate to the knee, usually occurring after periods of activity. As the condition progresses, the pain is more constant and may cause sleep disturbance. Other symptoms may include stiffness, and limping. The Trendelenberg test examines the strength and function of the hip abductor muscles.
The examiner should perform the test by getting the patient to first stand on the ‘good’ leg and flex the other leg at the knee. This is repeated for the ‘bad’ leg. With normal function, the pelvis is held stable by the gluteus medius acting as an abductor in the supporting leg. A positive result is seen when the patient has a weak or a mechanically disadvantaged
gluteus medius. This results in the pelvis ‘sagging’ down on the contralateral side. In this case when the patient stood on her left leg, the weakened gluteus medius on this side resulted in the right side of the pelvis dropping downwards.
A Trendelenberg gait demonstrates the same weak abductor mechanism. Normally when walking, the hip abductors are required to lift the pelvis and leg on the opposite side during the swing phase. If the abductors are not working, then the pelvis will tip downwards towards the lifted foot.
Other frequent examination findings with osteoarthritis of the hip !
• The affected leg is held adducted and in external rotation
• A positive Thomas’ test: demonstrates a fixed flexion deformity
• Restriction of movements of the hip joint
• Normal knee and back examination
• The Trendelenberg test is used to determine the strength and function of the hip abductor muscles.
This woman’s progressive symptoms and pain at night would suggest that she would benefit from a hip replacement.