Hip arthroplasty explained

In his latest online article, Mr Matthew Oliver gives us his insights into hip arthroplasty. He talks about what it is and how it works, the different types of hip implants available for arthroplasty, the recovery process, potential risks and complications, how long you can expect it to last and lifestyle adjustments.

What is hip arthroplasty and how does it work?

Hip arthroplasty, also known as total hip replacement, is a surgical procedure aimed at alleviating pain originating from the patient's hip joint. This pain can stem from various sources, predominantly from joint wear and tear, commonly referred to as osteoarthritis. Additionally, it might be a result of degenerative changes following a past injury, like a poorly healed fracture requiring surgery. Other factors contributing to hip joint deterioration include conditions like avascular necrosis. Rheumatoid conditions, while historically involved, are now primarily managed through medical treatments. Consequently, a total hip replacement or arthroplasty serves as a surgical intervention to replace the hip joint, ultimately diminishing pain and enhancing functionality.

What are the different types of hip implants available for arthroplasty?

Numerous variations of hip replacements are available, falling into distinct categories. These include the less commonly used hip resurfacing implants, the well-established conventional total hip replacement, and the preference for some surgeons to employ the short stem total hip replacement. In my practice, I opt for the conventional total hip replacement due to its robust clinical history and reliability. The ODEP rating (Orthopaedic Devices Evaluation Panel) assesses the long-term performance of these implants. In my practice, I specifically select implants with a survivorship of at least 10 years or more (ODEP rating 10+).

Additionally, there exist three primary methods for securing a hip replacement within the bone. One involves full cementation, where the acetabular cup is adhered to the pelvis, and the femoral component is fixed to the top of the thigh bone with bone cement. The alternative approach is cementless, wherein the cup and stem are fitted into the bone, allowing the patient's bone to grow into the implants—a preferable choice for younger patients or those with robust bone structure, but not recommended for individuals with porous or weak bones.

The third method involves a hybrid hip replacement, combining elements of both approaches. This entails an uncemented press-fit acetabular component with a cemented femoral stem. A significant portion of my practice is dedicated to these procedures, a choice further supported by data from the National Joint Registry showing excellent survivorship.

What is the recovery process like after a hip arthroplasty surgery?

The recovery phase following a hip replacement is typically less painful than that of a knee replacement, although it can be uncomfortable, particularly during the initial few weeks. Immediately after the operation, the lower part of your body will likely feel numb due to the spinal anaesthesia. However, this effect usually wears off within hours, typically by the afternoon if the surgery was performed in the morning. It's beneficial for the physiotherapist to encourage the patient to get up and start walking with a frame soon after. The implant is designed to bear your weight immediately, promoting early mobilisation. The key focus is on regaining confidence right from the start.

By the evening of the surgery day or the following morning, progress to using two crutches is encouraged. Patients often use crutches for several weeks, gradually transitioning to one crutch, then a stick, and ideally, being crutch-free around six weeks post-surgery. However, some individuals might need a crutch or a stick for an extended period, and complete recovery from a hip replacement can take up to a year. In my experience, most individuals comfortably resume most activities within about three months.

What are the potential risks and complications associated with hip replacements?

The risks and complications associated with a hip replacement can be categorised into anaesthetic risks, which the anaesthetist discusses in more detail pre-operatively, and the surgical risks that I typically concentrate on.

Regarding the surgery, a hip replacement does pose potential risks, such as the development of deep vein thrombosis (DVT) or pulmonary embolism. However, we now utilise blood-thinning agents for about a month post-operation, along with mechanical aids like anti-embolism stockings and foot pumps, to significantly reduce the likelihood of these complications until the patient becomes mobile.

Other risks include the possibility of bleeding, with a minimal chance of needing a blood transfusion. Nerve damage can occur, leading to slight numbness around the scar, and in rare cases, temporary foot drop might ensue due to bruising of the sciatic nerve in the hip area. While infection is a potential risk, in the hospitals I work in, the chance is generally one percent or less. However, a deep infection, though rare, can necessitate additional surgeries and, in severe cases, removal of the implant alongside long-term antibiotic treatment and revision surgery.

Fracture to the bone and the risk of dislocation are additional concerns, which I mitigate by ensuring accurate implant placement, while it's crucial for the patient to diligently follow their physiotherapy program to avoid these issues. A slight leg length difference may occur, but I take measures pre-operatively to minimise this by accurately planning the implants and bone cuts. The difference is typically within a centimetre and often goes unnoticed by most patients.

Rarely a patient might experience lengthening in the operated leg, leading to potential long-term backache and leg length imbalance. Hip replacements have a finite lifespan due to aseptic loosening, generally lasting 15 to 20 years, but various factors like activity levels, general health, and accidents can impact the duration.

While some individuals might experience residual pain post-replacement, most individuals tend to forget about the surgery after a few years, resuming their normal routines.

How long can I expect my new hip implant to last and are there any lifestyle adjustments I should make after the procedure?

A modern total hip replacement, performed with advanced surgical techniques, should generally endure, I estimate, for a minimum of 15 to 20 years. The choice of the bearing couple, particularly the combination of a ceramic femoral head with a plastic liner in the hip replacement socket, has displayed excellent long-term outcomes, supporting the aforementioned longevity estimate of around 15 to 20 years.

In the initial six weeks post-operation, it's advisable to take precautions: avoid sitting on low or slouchy sofas, attempt to sleep on your back, and be cautious when bending down to pick things from the floor. It is important one does not rush their recovery doing too much too soon as this may lead to inflammation of the hip muscle tendons.

However, with meticulous surgical technique, correct implant positioning, patient compliance, and cooperation with the physiotherapist, restrictions are typically eased after about six weeks. Following this period, life can return to almost normal. While some activity restrictions exist after a hip replacement, individuals often surpass these boundaries, engaging in activities such as cycling, golf, and taking leisurely walks. A hip replacement, particularly for individuals experiencing significant hip pain, can be a life-altering procedure, effectively restoring their quality of life.

Mr Matthew Oliver is a distinguished orthopaedic surgeon with over 25 years of experience. You can schedule an appointment with Mr Oliver on his Top Doctors profile.