The hip joint is one of the joints in the human body that bears the heaviest load. When the protective cartilage wears down over time, doctors refer to this as hip osteoarthritis or coxarthrosis (also known as koxarthrosis). This degenerative disease of the hip joint often leads gradually to hip pain, which initially occurs only during physical activity but later also at rest. Whether caused primarily by aging or secondarily by misalignments such as hip dysplasia: the progressive wear and tear severely limits mobility and quality of life. Treatment for hip osteoarthritis ranges from conservative measures such as physical therapy to joint replacement with a total hip replacement (THR) when the osteoarthritis is advanced.
What is hip osteoarthritis?
In healthy people, the cartilage ensures that only indirect friction occurs between the femoral head and the femur. Various underlying conditions can cause the articular cartilage in the hip joint to wear down progressively. This condition is known as hip osteoarthritis or coaxarthrosis (ICD code: M16).
In contrast to inactive hip osteoarthritis, active hip osteoarthritis is characterized by signs of inflammation. Tiny fragments of cartilage tissue are then released into the synovial fluid, triggering inflammation.
The video shows joint wear caused by cartilage damage:
Hip osteoarthritis often goes undiagnosed for years and usually does not become apparent until later in life. X-rays and ultrasound examinations are used for diagnosis.
How does hip osteoarthritis develop?
Hip osteoarthritis always involves wear and tear of the articular cartilage. Over time, the cartilage becomes thinner and thinner, develops tears, and becomes rough. Initially, only small areas are affected by the damage. The patient does not experience any symptoms at first.
As the cartilage breaks down, the pressure on the underlying bones increases steadily. So-called subchondral sclerosis develops on the bone. These are bony outgrowths in the hip joint that form to compensate for the increased pressure and wear.
To compensate for the pressure, the joint surface enlarges and forms osteophytes, which make the hip joint less mobile. This process continues to progress until the cartilage layer is completely worn away and the bones rub directly against one another without protection.
What are the causes of hip osteoarthritis?
The causes of coxarthrosis can generally be divided into two groups.
Primary cause
Especially in patients over the age of 50, it is often impossible to pinpoint an exact cause of osteoarthritis. It is simply a congenital weakness of the body that develops due to age-related degenerative processes.
Secondary causes
Secondary causes include
- congenital malformations (hip dysplasia),
- injuries to the hip joint resulting from accidents (usually as a consequence of an acetabular fracture),
- chronic overuse due to repetitive daily movements,
- obesity, and
- inflammatory conditions (rheumatism).
What are the symptoms of hip osteoarthritis?
Hip osteoarthritis is a chronic condition that usually develops over several years.
The main signs of the condition are
- increasing pain in the hip joint,
- increasingly limited range of motion, and
- muscle tension.
In cases of active hip osteoarthritis—which can occur in phases throughout the course of the disease—the following symptoms often occur as well
- swelling,
- redness, and
- overheating
.
The following symptoms characterize advanced coxarthrosis:
- Start-up pain: The patient experiences pain at the beginning of a movement, especially after prolonged periods of rest.
- Joint pain that occurs during weight-bearing
- Pain at rest: The patient experiences pain while lying down or sitting.
- Gait abnormalities: After prolonged weight-bearing, a slight buckling of the leg on the side affected by osteoarthritis is noticeable.
- Limited range of motion: The thigh becomes more difficult to bend, rotate, and straighten. The patient experiences pain when abducting the thigh.
How is hip osteoarthritis diagnosed?
Physical examination for the diagnosis of hip osteoarthritis
The examination begins with a physical examination, during which
- gait,
- posture,
- muscle weakness,
- compensatory postures, and
- possible misalignments
are the main focus. In cases of advanced hip osteoarthritis, the leg can no longer rotate inward, and deep flexion (while sitting) is no longer possible.
Imaging Techniques for Diagnosing Hip Osteoarthritis
On an X-ray, the narrowing of the joint space between the hip bone and the femur, along with the associated cartilage loss, is clearly visible. The narrower the joint space, the more advanced the hip osteoarthritis.
Osteophytes and subchondral sclerosis are also detectable on X-rays.
An important factor for the digital planning of a hip prosthesis is
- the femoral neck angle and
- the distance from the center of rotation of the femoral head to the femur.
In some cases, specialized imaging studies such as
- MRI,
- CT, or
- scintigraphy
may be used.
How is hip osteoarthritis treated?
The course of hip osteoarthritis varies and depends on many different individual factors.
There are various treatment options available, ranging from conservative measures to the implantation of an artificial hip joint.
Conservative Treatment
In the early stages of hip osteoarthritis, patients can benefit from specific measures such as
joint-friendly exercise routines,
- massage,
- physical therapy,
- orthopedic shoes, and more
significantly help slow the progression of the disease.
If the disease is more advanced, medications can help relieve pain and reduce inflammation.
Preventive measures also include weight loss and exercises that place minimal stress on the hip joint.
The Use of a Hip Replacement for Hip Osteoarthritis
In the end stage of hip osteoarthritis and when quality of life is severely impaired, surgical options should be considered. One possibility is the implantation of a hip prosthesis,
FAQ: The 8 Most Important Questions About Hip Osteoarthritis (Coxarthrosis)
What are the typical symptoms of coxarthrosis?
The main symptom is pain in the groin that worsens with activity and often radiates into the thigh or knee. Initially, this pain occurs as “start-up pain” after getting out of bed. Over time, pain at rest and nighttime discomfort develop. Hip mobility decreases, which is particularly noticeable when rotating the leg or bending over. In advanced stages, coxarthrosis leads to a protective limp and a reduced walking distance.
How is hip osteoarthritis treated?
Treatment for coxarthrosis is tailored to the stage of the disease. In the early stages, conservative treatment is the primary focus. This includes physical therapy to strengthen the muscles that stabilize the joint, as well as physical therapy (heat/cold). Medications such as anti-inflammatory drugs help relieve pain. If the wear and tear is far advanced and quality of life is severely impaired, surgery is often necessary to implant an artificial hip joint (total hip replacement).
When is hip surgery necessary?
The decision on when hip surgery is appropriate depends on the patient’s level of suffering. If conservative measures such as pain relievers and physical therapy are no longer sufficient to relieve the pain, the walking distance is significantly reduced, and pain at rest is disrupting sleep, joint replacement is usually recommended. A total hip replacement (THR) replaces both the head of the femur (caput femoris) and the hip socket.
What causes hip osteoarthritis?
A distinction is made between primary coxarthrosis, which usually occurs in older adults without any identifiable underlying condition, and the secondary form. Secondary causes can include congenital malformations (dysplasia), the consequences of accidents, inflammation, or circulatory disorders (avascular necrosis of the femoral head). Being overweight and uneven stress on the joint caused by certain sports also contribute to the wear and tear of the articular cartilage.
What can you do yourself to manage hip osteoarthritis?
To slow the progression of the disease, low-impact exercise is ideal. Cycling and swimming lubricate the joint without putting pressure on the cartilage. Losing weight noticeably relieves pressure on the hip. Targeted exercises strengthen the muscles around the pelvis and thigh. Wearing shoes with soft soles also helps absorb shock while walking.
How is the diagnosis made?
The orthopedic surgeon begins with a medical history and a physical examination, during which they assess your gait and range of motion (e.g., rotation tests). An X-ray taken while standing reveals typical signs such as a narrowed joint space, debris cysts, and bony spurs (osteophytes). In unclear cases or for surgical planning, imaging techniques such as MRI or CT scans can be helpful.
What is an acute flare-up of osteoarthritis?
An active phase of osteoarthritis is an inflammatory flare-up in the chronic course of coxarthrosis. The synovial membrane becomes inflamed due to abrasion by cartilage or bone particles. The joint swells, becomes warm, and causes acute pain even at rest. During this phase, anti-inflammatory treatment and rest are the primary focus of coxarthrosis management.
How long does an artificial hip joint last?
Modern hip prostheses have excellent durability. Statistics show that after 15 to 20 years, over 90 percent of prostheses are still intact. However, the lifespan also depends on the patient’s activity level, body weight, and the fixation technique (cemented or cementless).
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Sources
- S2k-Leitlinie „Koxarthrose“ (AWMF-Register-Nr. 187-049), Stand 05.07.2019: register.awmf.org/de/leitlinien/detail/187-049
