Hip osteoarthritis is a degenerative joint disease characterized by the progressive loss of articular cartilage within the hip joint, narrowing of the joint space, and the formation of bone spurs. It is one of the leading causes of chronic hip pain and disability in adults.
Hip osteoarthritis is often the end result of decades of mechanical stress on the joint — but in many patients, an identifiable upstream condition is responsible. Femoroacetabular impingement (FAI) is now recognized as one of the most common causes of early hip arthritis in active adults, as the abnormal bone contact gradually damages cartilage over years. Hip dysplasia and prior conditions such as Legg-Calvé-Perthes disease and slipped capital femoral epiphysis are well-established causes of secondary arthritis that often presents earlier in life. Avascular necrosis of the femoral head can also progress to end-stage arthritis if untreated.
Causes
Primary osteoarthritis.
In most cases, hip osteoarthritis develops as part of the normal aging process without a specific identifiable cause. Genetic predisposition, joint mechanics, body weight, and the cumulative effects of a lifetime of hip use all contribute to cartilage breakdown over time. Women are more commonly affected than men, and the incidence rises significantly after age 50. Obesity is a particularly important modifiable risk factor — each unit increase in BMI measurably accelerates cartilage loss and symptom progression.
Secondary osteoarthritis.
Secondary hip arthritis develops as a consequence of prior hip injury or disease. Femoroacetabular impingement, hip dysplasia, prior fractures involving the joint surface, avascular necrosis, Legg-Calvé-Perthes disease, slipped capital femoral epiphysis, and inflammatory arthritis such as rheumatoid arthritis can all substantially accelerate the degenerative process and cause osteoarthritis at a younger age than would otherwise be expected.
Symptoms
The hallmark symptom is a deep, aching pain in the groin or front of the hip that worsens with activity and is relieved by rest, at least in the early stages. Pain may also radiate to the thigh, buttock, or even the knee — the referred pain pattern of hip pathology to the knee is a well-recognized source of diagnostic confusion. Morning stiffness and stiffness after prolonged sitting that loosens with a few minutes of movement is characteristic of inflammatory and degenerative joint disease alike. Progressive loss of range of motion — especially internal rotation, which is the first and most reliably affected plane — leads to functional difficulty with putting on shoes and socks, getting in and out of a car, and climbing stairs. As the disease advances, pain occurs at rest and at night, and sleep disruption becomes a major quality-of-life concern.
Diagnosis
A physical exam by a doctor assesses gait pattern (the Trendelenburg sign and antalgic gait are common findings), range of motion in all planes, and provocation maneuvers including the FABER test (Flexion, ABduction, External Rotation) and the hip flexion with internal rotation test. X-rays are the primary imaging tool, demonstrating joint space narrowing, osteophyte formation, subchondral sclerosis, and cyst formation — and the standing AP pelvis view is the most informative single radiograph for grading severity. An MRI provides critical additional information: cartilage thickness and quality throughout the joint, labral status, bone marrow edema, and the presence of subchondral insufficiency fractures or avascular necrosis that can mimic or coexist with osteoarthritis. MRI is particularly important when X-rays underestimate the degree of joint damage or when the clinical picture suggests a diagnosis beyond simple primary osteoarthritis.
Arthritis severity (Tönnis)
Doctors use the Tönnis classification to grade the severity of hip osteoarthritis based on radiographic findings, which helps guide treatment decisions.
- Grade 0: No signs of osteoarthritis. Normal joint space and smooth articular surfaces.
- Grade 1: Mild joint space narrowing with minimal osteophyte formation and slight subchondral sclerosis. Symptoms are often manageable with conservative treatment.
- Grade 2: Moderate joint space narrowing with small subchondral cysts and moderate sclerosis. Conservative care provides diminishing returns; injections play a larger role.
- Grade 3: Severe joint space narrowing or obliteration with large cysts, significant deformity of the femoral head, and possible necrosis. Surgical intervention is typically required for adequate symptom control.
Treatments
Treatment depends on the severity of arthritis, patient age, activity level, body weight, and response to conservative care.
Initial management includes activity modification, weight loss when appropriate, low-impact aerobic exercise (swimming, cycling), ice or heat application, and anti-inflammatory medications.
Mild to moderate arthritis: Physical therapy to maintain hip range of motion and strengthen the hip abductors, extensors, and core musculature is the foundation of conservative management. Assistive devices such as a cane (held in the contralateral hand) significantly reduce joint reaction forces. Intra-articular corticosteroid injections provide meaningful short-to-medium-term pain relief and are most effective when the joint retains some preserved cartilage. Hyaluronic acid injections are used in some patients, though their evidence base is more modest than for corticosteroids.
Severe arthritis in active patients
Total hip arthroplasty (hip replacement) is the gold standard for patients with advanced arthritis that has not responded to conservative care. The arthritic femoral head and acetabular cartilage are replaced with prosthetic components, providing exceptional pain relief and restoration of function — it is one of the most successful and durable operations in all of orthopedic surgery. Modern implants routinely last 20 years or more, and minimally invasive surgical approaches have reduced recovery time substantially. After surgery, a structured physical therapy program is critical to restoring strength, gait mechanics, and full function.
Severe arthritis in older, lower-demand patients
Total hip arthroplasty remains the primary surgical option for older patients and is equally effective — in many studies, patient satisfaction following hip replacement is among the highest of any elective surgical procedure. Patient selection focuses on functional limitations, pain burden, and overall health rather than age alone. Many patients in their 70s and 80s undergo hip replacement with excellent outcomes and dramatic quality-of-life improvement.
Severe arthritis in younger patients
Younger patients — typically those under 50 — may be candidates for joint-preserving procedures in carefully selected cases. Hip resurfacing preserves femoral bone stock and may be appropriate for active younger men with good bone quality. Periacetabular or femoral osteotomy can redistribute joint loading in patients with underlying dysplasia or deformity. Arthroscopic debridement has a limited role in the setting of established arthritis. These options aim to delay the need for formal hip replacement and preserve future reconstructive options.
Get an MRI to Confirm Your Diagnosis
Before surgical planning or starting treatment, a clear MRI diagnosis ensures the right path forward. First Look MRI offers self-pay Hip MRI scans — no doctor's order or insurance required — at our locations in Georgia, Texas, and Colorado.