Hip Information

Mr Sam Patten

Hip joint

The hip is a ball and socket joint that consists of the upper end of the femur, or thigh bone, and the acetabulum, or pelvic bone. The head of the femur is ball shaped and fits into a cup shaped depression of the acetabulum.

The joint is supported by muscles, tendons and ligaments, and is designed for stability and mobility, allowing the leg to move in a variety of directions. The joint is lined with lubricating cartilage tissue which is normally smooth, and cushions the hip as it moves and bears the weight of the upper body.

The acetabular labrum is a tough cartilage ring which attaches to the rim of the hip joint socket. The main functions of the labrum are to deepen the socket and assist in the stability, lubrication or reduction of friction, and sensation of the hip joint.

Injury can occur to the these supporting soft tissue structures. The hip joint is also susceptible to osteoarthritis, due to wear and tear of the protective cartilage.

Hip Conditions

What is an Acetabular Labral Tear?

Acetabular labral tears generally occur in two situations. Tears can occur as a result of traumatic injury to the hip joint. More commonly however, tears may occur in a labral cartilage which has gradually accumulated damage over time; this is known as a 'degenerate tear'. Degenerative labral tears develop as a part of hip joint osteoarthritis, dysplasia, capsular laxity or femoro-acetabular impingement (FAI). The main cause of a traumatic tear is usually by twisting or pivoting whilst weight bearing.

Patients with acetabular labral tears commonly experience pain which can radiate into the groin, down the front of the thigh, buttock, greater trochanter and inside of the knee. This is often made worse with physical activity and positions where the hip is bent, such as deep squatting or rising from a low chair. The symptoms may have been present for a long time, and thought to represent 'recurrent groin sprains'. Some patients experience 'mechanical' symptoms such as a feeling of catching, clicking, locking, stiffening or unpredictable weakness or giving way of their hip, leading to a decrease in the range of motion.

What is FAI?

Femoro-acetabular impingement is a condition of too much friction in the hip joint where the ball or femoral head, rubs abnormally with the socket or acetabulum, creating damage to the joint. The damage can occur to the articular or joint surface cartilage, or the labral cartilage. There are generally two forms of FAI. The Cam form describes a loss of roundness to the femoral head contributing to abnormal contact between the head and acetabulum. The Pincer form describes the situation where the acetabulum has too much coverage of the femoral head, resulting in the labral cartilage being pinched between the acetabular rim and the anterior femoral head-neck junction. Often they exist together.

What is Hip Osteoarthritis?

Hip osteoarthritis is a relatively common condition due to the degenerative wearing process as the hip is a large weight bearing joint. The cartilage between the femoral head and the acetabulum wears away, allowing the bones to rub against each other. The joint can become uneven, pitted, erode, and develop bone spurs. This results in pain, stiffness, instability, limping, muscle weakness, and in some cases leg motion is greatly restricted. The degenerative process may be accelerated by a previous hip injury or bone fracture, certain childhood conditions, and being overweight which causes increased force on the hip joint.

What treatment is available?

Many patients with early hip joint damage can relieve and manage their symptoms of pain and inflammation without requiring surgery. If non-surgical treatments fail and there are persistent symptoms or significant injury, hip arthroscopy may be a suitable and successful treatment option for many conditions. For patients with a structural abnormality of the hip joint, consideration should be made to correcting the underlying cause. Generally Xrays and CT to detect bony abnormalities, and an MRI to assist identify soft tissue damage are requested. For significant bony degenerative changes a hip arthroplasty, or total hip replacement, is generally the most appropriate form of treatment.

Hip Arthroscopy
What is Hip Arthroscopy?

Arthroscopic hip surgery is minimally invasive or key-hole surgery using a narrow pencil sized fibre-optic camera and light to look inside the joint through a skin incision approximately 2cm long. Other small incisions or ports are made to pass instruments into the hip and perform surgery. Hip arthroscopy allows the surgeon to safely and accurately assess damage to the joint and to perform corrective procedures when required. Because less tissue is traumatized during surgery, than more extensive open procedures, the recovery is faster. For hip arthroscopy the bones of the hip joint must be separated by about 1cm to allow access of the camera and instruments. This is done by pulling on the foot with a special traction device and may lead to some bruising or temporary numbness of the foot, or temporary groin tenderness or numbness. The torn labrum can be trimmed using a shaver and in many cases the loose cartilage is repaired with a suture anchor. Also if there is an underlying structural abnormality in the hip joint which has pre-disposed the labrum to damage, this may be corrected. Hip Arthroscopy surgery is performed in about an hour and a general anaesthetic is required. You will generally have an overnight stay in hospital.

Hip Replacement
What is Hip Replacement?

Total hip replacement surgery replaces the damaged and diseased parts of the hip joint with specially designed artificial implants or prostheses. These generally consist of four components which include a femoral stem which is inserted into the shaft of the femur, a femoral head which is attached to the stem, and an acetabular component which is a shell inserted into the pelvic cup with an inner liner to allow smooth movement with the head. Hip replacement surgery is now a relatively common procedure in patients of varying ages, not just the elderly, as younger people with a predisposition to arthritis, an active sporting lifestyle, or overuse and wearing down of the hip joint, may also have symptoms which can be relieved by joint replacement. Total hip replacement is often recommended for advanced osteoarthritis, certain hip or femur fractures, and avascular necrosis or lack of blood supply to the femoral head. The main aim of total hip replacement surgery is to provide pain relief and improve hip function and mobility.

What is Revision Hip Replacement?

Revision hip replacement means that part, or all of the primary hip replacement implants need to be revised or replaced, and so this procedure varies greatly for each person. This operation varies from minor adjustments to major surgery, with the primary aim to provide pain relief. Longevity or life span of an artificial or prosthetic hip varies for each person dependent on many factors such as activity level, weight, and the components used. Just as the body's normal components wear down, so do the artificial implants. Loosening of the femoral or acetabular prosthesis, wear on the plastic joint liner, dislocation or instability of the hip, infection, osteolysis or bone loss, or trauma such as a fall, may lead to the necessity of revision hip replacement surgery.