Information about

Hip Arthritis

Introduction

The hip joint is formed by two bones – the acetabulum and the femoral head. The acetabulum is cup-shaped (hemispherical) and is a part of the pelvis. Its diameter usually varies between 40 mm to 60 mm. The spherical femoral head is the uppermost part of the femur (thigh bone), and is located within the hemispherical cavity of the acetabulum. The femoral head moves quite freely in all directions within the confines of the acetabulum. Thus, the hip joint is a ball-and-socket joint.

Arthritis of hip means destruction of the hip joint due to damage to the cartilage, which exposes the underlying bone. Progressive destruction of the joint leads to wearing off of the bone. This causes changes like osteophyte formation (bone spurs at the edge of the joint) and synovitis (thickening of joint cover).

The adjoining figure shows a femoral head (ball) with arthritic changes. This was removed from a patient with rheumatoid arthritis.

Causes of Hip Arthritis

  1. Osteoarthritis (OA) – This is age-related wear and tear occuring usually after the age of 50 years.
  2. Rheumatoid arthritis (RA) – There are chemical and autoimmune changes in the body which can affect any joint, including the hip and knee. RA occurs three times more commonly in females, and occurs at any age.
  3. Arthritis due to Avascular Necrosis (AVN) – This condition is caused by loss of blood supply to the femoral head, which can be due to alcohol, steroid overuse or femur neck fracture.
  4. Secondary arthritis (Post-traumatic arthritis) – This can occur after fractures around the hip joint.

Patient’s complaints in Hip Arthritis

The patient has pain in the hip, which can be felt in the groin, and may also radiate to the buttocks, thigh and knee. Pain is felt at rest; and also during any activity which involves movement in the hip joint, such as walking, sitting cross-legged, climbing up or down the stairs, and getting up from sitting position. In severe arthritis the patient is severely disabled with pain. In some cases there is shortening of the leg and internal or external rotation deformity.

Investigations

A thorough clinical examination is followed by a set of blood tests, X-Rays and other investigations. The changes seen on the X-Ray in an arthritic hip are:

  • Joint space narrowing
  • Osteophytes (bone spurs)
  • Sclerosis (thickened whitish areas in the bones near the joint surface)
  • Bone cysts
  • Deformity or abnormal alignment
  • Osteoporosis (usually seen in rheumatoid arthritis or in elderly patients)

Treatment of Hip Arthritis

Patients with mild to moderate hip arthritis can be usually treated with painkillers, physiotherapy, weight reduction and lifestyle modifications.

However, in severe arthritis, medications will relieve pain only for a short duration, while their prolonged use will be harmful to the stomach, liver and kidneys. In such cases, one may consider total hip replacement (THR) surgery as an effective and permanent solution. THR can relieve pain and restore the patient to near-normal level of daily activities.