Hip osteoarthritis occurs when the cartilage, bone, and other tissues in the hip break down. This process often occurs gradually, over many years. Osteoarthritis can cause pain, inflammation, and decreased range of motion in the hip joint.
Hip osteoarthritis may cause pain in different areas, including the hip joint itself, groin area, buttocks, or the front or back of the thigh. Symptoms may also include stiffness around the hip joint. Severe hip arthritis may make walking difficult.
Read this page or watch our hip osteoarthritis video to learn more about how hip osteoarthritis develops and causes symptoms.
The hip is a ball-and-socket joint:
- The hip joint’s ball is called the femoral head. It is the rounded, upper part of the femur (thighbone).
- The hip joint’s socket is called the acetabulum. It is part of the pelvic bone.
The femoral head fits into the acetabulum. The surfaces of the femoral head and acetabulum are covered by a smooth, slippery, flexible material called articular cartilage. This cartilage protects the bony surfaces from impact and friction during movement, such as walking, running, and jumping.
See Hip Anatomy
Another strong piece of cartilage rings the outer portion of the hip’s socket. This cartilage is called the hip labrum, and it helps deepen and stabilize the hip joint.
Cartilage in the hip breaks down
A hallmark sign of hip osteoarthritis is a loss of articular cartilage. This loss may be caused by biomechanical factors related to the hip joint’s shape and muscle function, a previous injury, or repetitive stress from sports or on-the-job activities. Other factors include age, sex, weight, and genetics. Additional research suggests that low-grade inflammation throughout the body, joint biochemistry, and other factors also contribute to the development of osteoarthritis. 1 Jefferies, MA. Osteoarthritis. In: Efthimiou P, ed. Absolute Rheumatology Review. Springer Nature Switzerland AG; 2020; chap 15. Accessed September 15, 2020. https://doi.org/10.1007/978-3-030-23022-7_15 , 2 Millerand M, Berenbaum F, Jacques C. Danger signals and inflammaging in osteoarthritis. Clin Exp Rheumatol. 2019 Sep-Oct;37 Suppl 120(5):48-56. Epub 2019 Oct 15. PMID: 31621566.
As the cartilage wears away, the space between the femoral head and acetabulum gets smaller.
As cartilage breaks down and disappears, the underlying bone will be subject to excess fiction and stress.
The hip’s bones undergo changes
Osteoarthritis affects the bones of the hip joint. These changes may be visible on x-rays and other medical imaging.
- Bone spurs (osteophytes) develop around the edges of the femoral head and acetabulum. Bone spurs alone will not cause pain, but they can lead to friction that contributes to painful inflammation. Bone spurs can also prevent the femur from fully rotating in its socket, decreasing the hip joint’s range of motion.
- The bony surfaces of the femur and acetabulum that lie just beneath articular cartilage can change in composition and harden. This condition is called subchondral bone sclerosis.
- The hip’s bones may develop cysts and areas of abnormal swelling called bone marrow lesions. These lesions may be associated with pain. 3 Sandhar S, Smith TO, Toor K, Howe F, Sofat N. Risk factors for pain and functional impairment in people with knee and hip osteoarthritis: a systematic review and meta-analysis. BMJ Open. 2020 Aug 7;10(8):e038720. PMCID: PMC7418691 DOI: 10.1136/bmjopen-2020-038720
The hip joint may undergo other changes, too. For example, the hip joint’s lining (synovial membrane) may become inflamed, resulting in hip pain, swelling, and stiffness.
Hip arthritis doesn’t always cause symptoms
It is possible to have hip osteoarthritis—particularly mild arthritis—and not experience pain or other symptoms. 1 Jefferies, MA. Osteoarthritis. In: Efthimiou P, ed. Absolute Rheumatology Review. Springer Nature Switzerland AG; 2020; chap 15. Accessed September 15, 2020. https://doi.org/10.1007/978-3-030-23022-7_15 , 4 Murphy NJ, Eyles JP, Hunter DJ. Hip Osteoarthritis: Etiopathogenesis and Implications for Management. 2016; Advances in therapy 33, 1921-46. PMCID: PMC5083776 DOI: 10.1007/s12325-016-0409-3 Even at its later stages, hip osteoarthritis symptoms are unpredictable, and it is possible to have severe, bone-on-bone osteoarthritis and have mild or no symptoms. It is unclear why these differences exist.
It’s possible to treat hip osteoarthritis
Treatment can include the prevention and management of hip osteoarthritis symptoms. A health care practitioner can help you identify the best treatment options based on the severity of your arthritis, overall health, and lifestyle.