Hip osteoarthritis

What is hip osteoarthritis?

Risk factors

What is hip osteoarthritis?

Hip joint osteoarthritis is commonly seen in middle-aged and older people. The knee and hip joints, in particular, are commonly involved with osteoarthritis as they are the main load-bearing joints within the body. Osteoarthritis of the hip refers to the wear and tear changes that result in thinning and loss of the articular cartilage. The cartilage is the protective tissue that covers the bones at the joints, and it is responsible for smooth and frictionless movement. As a result, the bones will be exposed and may rub against each other, resulting in joint pain and reduced movement. In severe cases, there might be crepitus (a grating sensation due to bone rubbing on bone). This is usually called “bone on bone” and indicates severe osteoarthritis. Swelling may happen due to the accumulation of fluid within the joint.

What are the risk factors for hip osteoarthritis?

Hip joint osteoarthritis is commonly seen in association with:

Increased body mass index
Age
Previous injuries to the hip joint, for example, previous fractures that involve the hip joint. This is referred to as "intra-articular fracture".
Altered hip/lower limb biomechanics.
Congenital predisposition, due to abnormal hip anatomy and development (for example hip dysplasia).
Sports involve increased stress upon the joint, particularly if they are repetitive over years.

Hip joint anatomy

The hip joint is a ball and socket type joint. The ball is the head of the femur (the leg bone) and the socket is part of the hip bone (called the acetabulum). Osteoarthritis of the hip refers to the wear and tear changes that result in thinning and loss of the articular cartilage. This will result in bone exposure and bone rubbing against each other, resulting in hip joint pain and inflammation. The hip joint is covered by a layer of tissue called "the synovium". This can also get inflamed and painful also, which is referred to as "synovitis". The inflammation can be associated with excess fluid within the hip joint leading to joint swelling, stiffness and pressure feeling. The excess fluid production is referred to as "joint effusion".

How can I know if I have hip osteoarthritis?

The clinical features of hip osteoarthritis depend on the grade of changes and include:

- Gradual pain that usually progresses over months or years. The pain can increase in cold weather or feel more severe at the end of the day. Typically, pain and stiffness associated with hip osteoarthritis are most noticeable in the morning and feel better after warming up. It can feel worse after activities (like going upstairs and squatting). An acute flare can cause sudden severe joint pain and swelling.

Hip osteoarthritis pain is usually felt more in the groin area and sometimes at the side of the hip. It can also extend to the thigh and the knee. Please read our article about pain at the front of the hip to find out more.

-The pain and symptoms can be episodic, and you may experience good and bad days. The pain is usually associated with stiffness and sometimes swelling.

-If arthritis progresses, the pain will become more noticeable and can be associated with significant joint movement and limping loss. It can interfere with simple daily activities (like bending down to do your shoelaces and getting in and out of the car). The pain can also interfere with sleeping in severe cases.

How is hip osteoarthritis diagnosed?

A hip X-ray is usually helpful in determining the severity of osteoarthritis and the degree of joint space narrowing. Sometimes, more advanced imaging (called MRI) is required to provide more information about the state of the articular cartilage and the soft tissues stabilising structures of the hip joint. Ultrasound is very useful to assess for the presence of any fluid within the hip joint as well as assess the tendons around the hip. Furthermore, it is useful in guiding injection treatment around the hip joint. Please see our article to find out more about ultrasound-guided hip injections.

It is essential to mention that the radiological findings need to be correlated with the clinical picture. It is not uncommon for patients to experience hip pain, while the X-rays show only mild hip arthritis. In such cases, an MRI examination would be useful to assess the hip joint structures and the articular cartilage in more detail.

Normal hip X-ray. Note the preserved joint space to both hip joints (arrows).

Severe hip osteoarthritis. Note the complete loss of the joint spaces (arrows)

What other conditions can mimic hip osteoarthritis?

Other conditions that can be mistaken for hip arthritis include:

Hip Osteoarthritis vs hip (trochanteric) bursitis

In hip osteoarthritis, the pain is usually felt at the front of the hip or in the groin region. In contrast, in hip (trochanteric) bursitis, the pain is felt at the outside of the hip and can extend down the thigh. The hip bursitis pain usually gets worse when lying on the affected side. To learn more, please see our article Hip (trochanteric) bursitis.

What is the treatment for hip arthritis?

Hip osteoarthritis treatment usually starts with physiotherapy. Some people respond very well to physiotherapy and a progressive rehabilitation program. This usually comprises strengthening exercises, joint mobilisation and soft tissue techniques. The first aims to increase the strength within the gluteal and hip flexors to help support the hip joint. Anti-inflammatory tablets (like Ibuprofen and Voltarol) are also helpful in managing hip osteoarthritis to help reduce the pain and inflammation associated with this condition. So, the first line of treatment usually consists of exercise/physiotherapy, weight loss, activity modification and education on arthritis.

Will I benefit from a hip joint injection for my arthritis?

An injection may be indicated if the arthritis is severe and does not respond to conservative treatment. This can be very useful in reducing pain, allowing you to undertake a rehabilitation program. One injection option is an ultrasound-guided steroid injection. This can provide rapid pain relief and is usually followed by a course of physiotherapy to utilise the window achieved by the injection to get good results with exercise and rehabilitation. Hyaluronic acid and PRP injections can provide an alternative to steroid injections and can be helpful in the management of hip arthritis. They are usually used for mild to moderate osteoarthritis in active individuals. To learn more, please see our article about the stages of hip joint arthritis. Hip replacement is usually one of the latest treatment options, reserved for those with severe osteoarthritis that is not improving with injections and physiotherapy.

In ultrasound-guided hip joint injections, the ultrasound visualises the needle, guiding it accurately to the intended target. Evidence shows that this technique is significantly more accurate, less painful and produces better results than non-guided injections.

What are the available injections for hip osteoarthritis?

Ultrasound-guided corticosteroid injection

Corticosteroid (cortisone) is a well-established medicine routinely used to manage osteoarthritis. It has a strong anti-inflammatory effect that is usually very effective in reducing the pain and inflammation associated with osteoarthritis. Cortisone is usually mixed with a short-acting local anaesthetic (numbing medicine) to provide quick pain relief. Many patients experience a significant reduction in their hip pain and a quick return to previous levels of function after a corticosteroid injection. To find out more, please read our article about hip joint steroid injections

Ultrasound-guided hyaluronic acid injection

Hyaluronic acid can be useful in managing hip osteoarthritis, particularly mild and moderate arthritis. It has a dual role as it acts as an anti-inflammatory medication and aims to simulate the joint's natural lubrication allowing for movement in a low-friction environment. To find out more, please read our article about Hyaluronic acid injections

Combination therapy

Corticosteroids and hyaluronic acid can be combined, but we prefer not to combine these for the treatment of hip osteoarthritis.

Ultrasound-guided platelet-rich plasma (PRP) injections

Ultrasound-guided PRP injection involves taking a small amount of your blood, which will be spun in a special machine at high speed to separate it into different components. The plasma component can then be extracted. The plasma contains high levels of growth factors, which are very useful for tissue healing. The plasma that is rich with the growth factors is re-injected into the hip joint aiming to promote a natural healing response to the cartilage. In addition, the re-injected plasma has an additional anti-inflammatory effect to help reduce the pain and symptoms associated with osteoarthritis. There is good evidence of the positive effect of PRP injections in treating arthritis. To find out more, please read our article about Ultrasound-guided platelet-rich plasma (PRP) injections

Are hip steroid injections safe?

Yes, generally these injections are very safe and routinely done in our practice. There is a very small risk of infection (about 1:10.000). The procedure will be explained to you in detail during your appointment and all your questions will be addressed. To find out more about cortisone injections in general, please see our FAQs.

How long will the effect of a hip cortisone injection last?

Current evidence suggests that cortisone can improve pain and function for up to 3 months, but in some cases, it can last longer. The injections usually also contain a local anaesthetic that provides immediate pain relief lasting a few hours.

How soon will a steroid injection start to work?

A steroid injection usually takes a few days (1-3) before you notice the effect, although sometimes the pain relief can start on the same day. More commonly, the injected area will feel sore for the first few days. This is referred to as (steroid flare) and can be seen after a steroid injection. Other injections like PRP and intra-articular Hyaluronic acid injections can take a few weeks (2-5 weeks) before noticing any results.