Osteoarthritis of the hip is a frequent cause of hip pain in the general population. It is more common as people age, but is a significant problem becoming more prevalent in younger patients. The predicament in these patients is the loss of the smooth cartilage on the end of the bones that normally allows the bones to glide with little resistance during hip motion (Figure 1). Osteoarthritis implies that the cartilage injury is from general wear and tear as opposed to cartilage injury after trauma or in the setting of an inflammatory disease, such as, rheumatoid arthritis.
Image 1 – Normal hip versus arthritic hip
The determining factor in the development of osteoarthritis is genetics. Although we have not isolated specific genes responsible for the development of osteoarthritis, the condition often runs in families. Another element in the progression of osteoarthritis is repetitive microtrauma to the cartilage based on the patient’s lifestyle and participation in high impact activities.
Recently, a strong association has been found between hip impingement and osteoarthritis in the younger patient.
History & Exam
The most common patient complaint is pain in the groin and hip region. Often the symptoms increase with activity and at the end ranges of motion. The pain in the hip may radiate down the leg and tends to become more problematic at night with progression of the disease. Patients notice increased stiffness and ultimately a loss of motion with time. Decreased motion can be seen with hip flexion and rotation.
Diagnostic Tests and Imaging
X-ray examination is the most common imaging test used to diagnosis and follow osteoarthritis. Common findings include joint space narrowing and bone spur formation. The joint space is considered the zone between the bone of the femoral head and acetabulum seen on X-ray (Figure 2). This space is filled with articular cartilage that is not seen on X-ray. As the cartilage wears away, this space decreases and the bones appear to converge on each other.
MRI is very sensitive and accurate in determining cartilage injury and may be used to better evaluate patients in the early stages of this process.
Example of normal joint space (a) and narrowed joint space (b) as seen in osteoarthritis.
There are numerous non-operative treatment options prior to the definitive surgical treatment of joint replacement. Examples of non-operative treatments include:
- Activity modification
- Physical therapy
- Glucosamine and chondroitin sulfate
- Steroid injections
- Hip arthroscopy