Artificial hip joint (hip prosthesis)

Overview of hip osteoarthritis

The hip joint consists of two main components: the acetabulum (hip socket) and the femoral head. Both joint surfaces are covered with a smooth cartilage layer, which together with the synovial (joint) fluid serves as a buffer and minimises friction during movement. If this protective cartilage is damaged or completely eroded due to wear and tear or other causes, this is known as hip osteoarthritis, a degenerative illness of the hip joint where bone rubs on bone in the joint. Reasons for this can be hereditary predisposition, excessive strain from sport or work, and many years of wear and tear over the course of ageing. Often, however, no actual cause is found.

Hip osteoarthritis is initially treated conservatively. Surgical treatment is used when other options have been exhausted and the osteoarthritis still continues to worsen. In the case of severe osteoarthritis, patients often opt for surgery because of the debilitating hip pain and significant loss of mobility.

A new hip joint is usually recommended when conservative treatments such as physiotherapy, pain medication or injections no longer provide sufficient relief. The most common reasons for hip replacement surgery include:

• Advanced hip osteoarthritis (coxarthrosis)
• Fractures of the femoral neck
• Inflammatory joint diseases such as rheumatoid arthritis
• Femoral head necrosis (death of bone tissue)
   

Treatment goal

The aim of a hip replacement surgery is to improve patients’ quality of life in the long term. The focus is on alleviating chronic hip pain, which severely impacts the quality and day-to-day life of those affected. At the same time, the surgery helps restore mobility, enabling patients to walk, exercise and engage in other activities. In addition, early intervention helps to prevent serious damage to muscles, ligaments and other joints by reducing undue strain and its long-term effects. The use of a hip prosthesis to treat advanced osteoarthritis in the hip joint is a proven treatment method with very good prospects of success.

Surgical procedure

Hip replacement surgery is generally carried out under general anaesthesia or spinal anaesthesia (spinal block) and as gently as possible using minimally invasive procedures. Where possible, muscles are not cut through, but simply pushed to the side. Once the hip joint is reached, it is dislocated and the hip head is removed and the acetabulum milled. The artificial hip joint made of titanium is then inserted. The new acetabulum is anchored to the pelvic bone and the artificial femoral head is mounted on a shaft that is fixed to the femur. Finally, the artificial hip joint is inserted. The stability is checked and the surgical wound closed. The intervention takes 60 to 75 minutes.

Preparation and precautions

Before the surgery, the severity of the hip osteoarthritis is examined in detail using modern imaging techniques such as X-rays, computed tomography (CT) or magnetic resonance imaging (MRI). This diagnosis makes it possible to accurately assess the joint’s condition. The next step is the precise radiological measurement of the hip joint. Important parameters such as the size and shape of the joint are analysed in order to be able to select the right hip prosthesis, ensuring that the artificial hip joint fits optimally and remains stable in the long term.

In addition, the standard medical examinations are carried out before the surgery to assess the general state of health. This includes a blood test, measuring blood pressure and an electrocardiogram to check heart function. If the patient is taking blood-thinning medication, a decision will be made in consultation with the attending doctor on whether this needs to be stopped temporarily in order to minimise the risk of bleeding during surgery. It is also important to fast on the day of the procedure, meaning that you should not eat solid food or drinks.

Aftercare and recovery

After the recovery phase and the subsequent transfer to your hospital room, mobilisation quickly begins. The hip prosthesis is resilient right from the start. You will take your first steps in the first few hours after the surgery, accompanied by a physiotherapist. You will learn a range of muscle-strengthening exercises that support the healing process and promote flexibility during your four to five-day hospital stay. The training programme also includes walking freely without walking sticks and climbing stairs safely. Before you are discharged, the hip prosthesis’ fit will be checked once more using an X-ray.

At home, you will independently continue the exercises you have learnt to further your recovery. To minimise the risk of falls, the use of walking sticks is strongly recommended for a certain period of time.

Another check-up is carried out around eight weeks after the surgery to check the healing process. Light physical activity can generally be resumed after four to six weeks. In the case of moderate or heavy physical work, the inability to work is extended to two to three months.

Potential complications

Hip replacement is one of the most common surgeries and is usually does not involve any complications. As with all surgeries, infections, nerve injuries, bleeding or blood clots may occasionally occur. In addition, slight groin pain may initially be noticeable due to the pressure of the retractors. Mild muscular pains can also occur in the first two to three months after the surgery. These symptoms usually subside completely. The greatest improvement can be seen within the first six months, although the condition can continue to improve afterwards. The final result is usually reached after about two years.

Modern prostheses have an impressively long durability. In most cases, around 90 percent of artificial hip joints still function perfectly after 15 to 20 years. In rare cases, however, the implant may loosen prematurely and the implant must be replaced in an operation where the loose prosthesis is removed and replaced by a new one.