Hip osteoarthritis (coxarthrosis)

Hip osteoarthritis — coxarthrosis — is the progressive wear of the cartilage covering the femoral head and the acetabulum. That cartilage is what lets the joint move without friction; as it thins, bone begins to work against bone, the capsule thickens and the hip loses movement even before it hurts a great deal.

It is not always “wear and tear with age”. In many patients there is an underlying cause: femoroacetabular impingement that had been damaging the rim of the acetabulum for years, mild dysplasia that was never diagnosed, avascular necrosis, or the aftermath of an old fracture. Identifying that cause matters, because it changes what can be offered and at what age.

How it feels

The characteristic pain is in the groin, and sometimes runs down the front of the thigh to the knee — so much so that some patients arrive convinced they have a knee problem. Many make a C shape with their hand over the hip to show where it hurts.

It worsens on walking, on rising from a low chair and on turning. Over time the signs that really shape daily life appear: difficulty putting on socks and shoes, difficulty getting in and out of the car, difficulty crossing the legs. Stiffness in the first minutes of the morning or after sitting is common. Night pain appears in more advanced stages and is usually the symptom that finally prompts a consultation.

How it is assessed

The diagnosis is clinical and radiological. On examination the most informative finding is limited, painful internal rotation, which appears early. The radiograph is taken standing, not lying down: under load the true joint space narrowing, subchondral sclerosis, cysts and osteophytes become visible.

MRI is not needed in most established osteoarthritis. It is reserved for ruling out avascular necrosis, assessing the labrum in a young patient, or clarifying an uncertain picture. And a caution that holds across orthopaedics: the radiograph does not hurt. There are hips with striking changes and little pain, and hips with moderate changes that are severely limiting. We treat the patient, not the image.

What the evidence says about treatment

International guidelines agree that the core treatment is directed exercise and patient education, with weight management where appropriate. This is not filler advice while surgery approaches: it is the best-supported intervention, and in many patients it maintains function and delays the need for surgery by years.

On medication the recommendations are more nuanced than is generally believed. Anti-inflammatories are used selectively and with judgement, weighing each person’s gastrointestinal and cardiovascular risk; opioids are not recommended for osteoarthritis. In the hip specifically, injections have a more limited role than in the knee: hyaluronic acid is not recommended routinely and intra-articular corticosteroids are used selectively. That said, an intra-articular injection is a valuable diagnostic tool when deciding whether the pain is coming from the hip or from the spine.

What does not exist today is a treatment that regenerates lost cartilage. No supplement, no injection and no device reverses established osteoarthritis.

When a replacement is considered

The radiograph does not make the decision: your life does. Replacement is considered when pain wakes you at night, when you can no longer walk the distances you need to, when you have given up things that mattered to you, and when properly delivered conservative treatment — not two weeks of therapy, a serious programme — is no longer enough.

Nor is it wise to wait until you are housebound: arriving at surgery with badly deconditioned muscle and months of inactivity behind you makes recovery slower. The right moment is a conversation, not a number.