The hip joint is a ball-and-socket joint located where the thigh bone (femur) meets the pelvic bone. The upper segment (head) of the femur is the round ball that fits inside the pelvic bone cavity, or socket, which is also known as the acetabulum. Both the ball and socket are covered with a layer of smooth cartilage which acts as a sponge to cushion the joint, allowing the bones to slide against each other with very little friction.

Osteoarthritis (OA) is often referred to as “wear-and tear” arthritis or degenerative joint disease. The hip joint is one of the body’s largest weight-bearing joints, secondary only to the knee joint, and is commonly affected by OA. OA is less common in the hip than in the knee. Recent study reveals the lifetime risk for a symptomatic hip is 18.5% for men and 28.6% for women. The prevalence of hip OA per 1,000 people per year is 0.9 and 1.6 in men and women, respectively. Several risk factors are linked to the development of hip OA, including age, gender, genetics, obesity and local joint risk factors. Caucasian populations have a higher hip OA prevalence than others. Also, having a sibling with hip OA increases the risk of developing the condition. Local joint risk factors include trauma, femoroacetabular impingement/labrum tear, congenital dysplasia or chondrocalcinosis.

The most common symptom of hip OA is pain in the groin area which could radiate into the buttocks or knee. Patients can also experience decreased hip motion, stiffness, a grinding noise (crepitus) or even locking of the joint. Patients may have difficulty walking, bending, or getting out of a car. Prolonged resting, sitting and getting out of the car can likewise aggravate groin pain. In general, movement and moderate activity that loosens the joint improves OA symptoms.

Physical therapy is the mainstay of treatment in mild or early hip OA and is aimed at strengthening hip muscles and maintaining joint mobility. Weight loss is crucial to decrease the weight load on cartilage and to slow down the progression of subsequent cartilage damage and arthritis. Total hip replacement (THR) is indicated for those patients who have intractable pain, failed nonsurgical treatment, or suffer severe functional impairment. The hips of patients who receive THR can remain functional for 10 to 25 years depending on general physical health, ability to exercise, active lifestyle, and maintenance of healthy weight. Prolonged delays correlate with worse clinical outcomes after THR. The use of Platelet-Rich Plasma (PRP) treatment remains under investigation in clinical trials.

Osteoarthritis of the hips can result in pain, reduced mobility, marked physical impairment and profoundly negative effects on daily activities. However, proper prevention and treatment can decrease the impact hip OA symptoms on daily life.

 

Dr. Yong H. Tsai is board-certified in rheumatology, allergy and clinical immunology and has been practicing in this area since 1993. His website is arthritis-allergy.net.