Causes of hip pain

In health, the hip joint surfaces are perfectly smooth, allowing almost friction-free movement. Osteoarthritis causes the articular cartilage joint lining to become worn-away. Often there is no obvious cause for this (termed "primary osteoarthritis"). This tends to occurs around middle age in people with a strong family history of arthritis. Secondary osteoarthritis occurs if disease conditions (such as dysplasia or  Perthes disease) result in abnormal anatomy and increased mechanical loading to the joint. If osteoarthritis becomes severe,  the bone surfaces rub directly against each other causing an uncomfortable grinding sensation. Pain is usually felt in the groin and thigh. There may be stiffness and a sensation of instability. Walking, exercise and deep flexion tend to aggravate symptoms. For some people, activity modification, pain killers and weight-loss may help, whilst for others, a total hip replacement will be more effective.

Healthy hips require a good blood supply. If this is disrupted, the bone may soften and die, causing collapse of the femoral head. This typically causes very severe pain with weight-bearing. There are many causes for this condition including exposure to steroids, trauma, high intake of alcohol and certain blood disorders (including sickle cell disease). In about 25% of cases, no obvious cause can be found. X-rays may appear normal in the early stages of the disease though the diagnosis can be reliably made using MRI scanning. If the condition is not advanced, avoidance of risk factors together with surgical procedures to restore the blood supply can be helpful. If the damage to the bone within the femoral head is advanced, replacement of the hip may be needed.

The femoral neck region (the upper part of the thigh bone just below the hip) is susceptible to fracture in patients who have weakened bone due to osteoporosis. This form of "broken hip" is usually seen in elderly female patients. Surgery is invariably required to either fix the fracture back into place or to replace the joint. Although less common, fractures in this region may also occur in young and fit people in association with physical training. So called "Stress fractures" of the femoral neck may present with progressive pain associated with a high level of physical activity (such as training for a marathon). Importantly, a simple X-ray may miss the diagnosis and a MRI is usually needed.

It is now recognised that certain variations of normal hip development can cause impingement between the outside of the hip socket and the femoral neck. Pain is initially felt when the hip is deeply flexed and the leg is brought in across the body. With time, stiffness may progress and damage to the joint itself can occur. Hip impingement may cause a tear at the cartilage rim of the socket (the "labrum") and with time may also result in wear of the joint surface.

Hip dysplasia refers to a broad spectrum of developmental abnormalities of that may cause hip pain. At one extreme is a situation whereby the femoral head develops outside of the socket (congenital hip dislocation). This results in shortening of the leg and an obvious limp. Thanks to screening of newborn children, this condition is now uncommon. A less severe form of dysplasia results in a shallow pelvic socket. The resulting abnormal loading of the joint may cause pain and osteoarthritis.  Because the abnormalities may be subtle, the diagnosis is sometimes missed. Surgery to form a more normal socket can reduce the chance of the joint wearing-out early

Pain in the buttock and upper thigh is often due to inflammation of the large muscles that stabilise the hip and straighten the leg. There may also be inflammation at the tip of the thigh bone where the the tendons of these muscles inset. Often pain is felt when lying on the painful side. Sometimes symptoms come on after a change in exercise regimen or following trauma. A range of treatments include rest, anti-inflammatory medications, stretches, injections and shock-wave therapy. 

For many people, occasional use of a simple pain-killer such as paracetamol may be all that is needed to keep their symptoms under control. Non-steroidal anti-inflammatories (such as ibuprofen) are often more effective but can have significant side-effects. Stronger pain killers containing opiates can become addictive and are best avoided. Dietary supplements such as glucosamine tend to not make any difference. Although not part of mainstream medicine, many patients report finding turmeric helpful. 

Often patients seek help when their hip pain makes maintaining their active lifestyle difficult. There is however good evidence that regular low-impact exercise such as cycling, swimming or pilates can help maintain hip flexibility and stave-of surgery. If on a bike, set the seat high with the handle-bars not too far forward. Swimmers may find breast-stroke uncomfortable but crawl tends to be well tolerated. Higher impact sports like road running or squash can irritate the hips; moving over to racquetball or an inclined treadmill can help. 

If the hip is very worn and painful, treatment with a physiotherapist will not cure the problem. However, working with a therapist will help build core strength, making some activities of daily living easier. This will also facilitate your recovery if surgery is eventually needed. For other hip conditions such trochanteric pain syndrome, physical therapy represents the mainstay of treatment.

Most people find the prospect of using a walking stick fairly unattractive (though if you do consider using one, it is more helpful in the opposite hand). A pair of Nordic hiking poles can be an effective  way of taking the load off painful joints when on more challenging terrain. Well cushioned trainers usually help whilst heels can aggravate. 

This form of non-invasive treatment is used to treat chronic soft-tissue inflammation. Although the mechanism of action is not well understood, the mechanical pulses are thought to stimulate healing. This treatment can be used trochanteric pain (at the side of the hip), as well as other conditions such as tennis elbow, patella tendonitis and plantar fasciitis. The results are not instant and treatment may be uncomfortable.

Injections can be used in the trochanteric area, around the major hip tendons or into the joint itself. Often ultrasound or X-ray is used to locate the exact spot. If the cause of pain is uncertain, injections of local anaesthetic alone may be used to clarify the diagnosis. More commonly, injections will include steroids and/or joint lubrication gel (viscoelastic supplementation).