Surgeries

Also referred to as Joint Arthroplasty, it is the replacement of a patient’s native joint with an internal orthopaedic implant that replicates the joint. The aim is to restore function through relieving pain and improving motion. Most commonly it is performed for arthritis, but can also be indicated for fractures. First successfully developed in the 1960s by Sir John Charnley for the hip; joint replacements have undergone significant advances and now offer increasing longevity and reliability of outcomes. The causes of arthritis can be broadly classified into primary osteoarthritis (from wear and tear of a joint), inflammatory (including rheumatoid arthritis), secondary (from previous trauma or infection) and as a consequence of AVN (avascular necrosis). Displaced fractures of the hip can disrupt the blood supply and lead to the development of AVN and arthritis, which is why a joint replacement is frequently indicated for fractures. In my practice I commonly perform joint replacements for hip, knee and shoulder arthritis and further information regarding each joint is outlined below.

Refers to replacing the entire hip joint, with a socket inserted at the acetabulum and a head at the femoral side. It is performed electively for arthritis of the hip, or as an emergency for a fracture of the hip. It can be implanted through a variety of surgical approaches, each with their own advantages and indications, namely the Posterior Approach, Direct Anterior Approach and the Lateral Approach. Ultimately the best approach to use for a patient is one that gives the surgeon safe access to the hip joint in order to correctly insert the implants. This may vary between patients, and I am happy to discuss this further at our consultation. There are a variety of implant designs for hips that can broadly be classified by the type of fixation at the bone implant interface: cemented or press-fit metallic. Both varieties are available for the acetabulum and the femur and each have their particular advantages and indications. There are also available a selection of different bearing materials (metal, polyethylene and ceramic) and a selection of different bearing sizes and an array of implant designs. I can address any questions you have regarding hip replacement at consultation. When performing a hip replacement there are multiple parameters that require careful assessment. These include selection of the optimal size of implant and insertion of the implant in the optimal position. I utilize a system of repeated checks that has some built-in redundancy. It includes routine trialing of all implant sizes and positions to check for the range of motion and stability of the hip before selecting and inserting the final prosthesis. The system has significant benefits for reliability and successful outcomes.

The knee replacement has overtaken the hip as the most widely implanted joint replacement performed in Australia and worldwide. The success is reflected in the more reliable outcomes the modern knee replacement has to offer. The surgery essentially replaces the joint surfaces of the femur and tibia with a size matched implant, most commonly metallic, with a polyethylene insert placed between the components acting as the bearing. A well functioning knee replacement restores motion, relieves pain and is a stable knee for the patient to walk on. During a knee replacement great attention must be paid to the ligaments and muscles that surround the knee joint to ensure the knee is implanted in an optimal position so these structures are all at the correct tension. This is referred to as “soft tissue balancing” and the technique I routinely employ is to undergo a number of checks before each major bone cut is made to ensure the balancing is accurate. Another factor affecting knee replacement outcome is joint alignment (and many robotics and computer navigational systems have been developed to try and improve the accuracy of this parameter). Although joint alignment is important, there is evidence to suggest that soft tissue balancing is equally important. Furthermore the natural knee joint alignment varies between individuals, and alignment that is tailored to the patient has been termed “kinematic alignment”. I’m happy to discuss the issues surrounding knee replacement at our consultation, including the possible use of computer navigation and robotics.

Shoulder replacement surgery is an area with recent rapid development and there are now multiple options available for the joint, customized to the shoulder problem. If the muscles and tendons surrounding the joint (the rotator cuff muscles) are torn or degenerate the best choice of replacement is often a Reverse shoulder replacement. Unlike the anatomic shoulder joint that replicates the normal anatomy of the ball and socket joint the reverse shoulder swaps the two over (so the socket is implanted on the ball side and the ball on the socket side). This allows the remaining muscles around the shoulder (particularly the deltoid) to function more effectively, compensating for the torn rotator cuff tendons and restoring motion to the joint. The reverse shoulder is also commonly implanted for fractures of the humerus that involve the joint and cannot be reconstructed. The anatomic shoulder is a replacement suitable for patients with arthritis in the presence of a well functioning rotator cuff. Imaging including X-rays and MRI scans help to differentiate between which shoulder replacement is better suited for the patient. I am happy to discuss the options of shoulder replacement further at consultation.

Refers to surgery that removes a previous joint replacement that has failed and reinserts a new replacement. The reasons for failing can include loosening (from longstanding wear or from a peri-prosthetic fracture), infection, dislocation or for symptoms of pain or instability. The surgery can be challenging depending on the particular problem being addressed. For infection it is sometimes more reliable to perform a staged revision procedure where the infected implants are initially removed and an antibiotic spacer is inserted for a number of weeks before a second procedure is undertaken to implant the new prosthesis. In some circumstances this can be done without the spacer option but with a thorough debridement of the infected soft tissues before the new implant is inserted. When performing revision knee replacements it is important to protect and preserve the soft tissues and ligaments whenever possible. There are prostheses available to compensate for deficiency in the ligaments that are called constrained implants. The most constrained revision knee implant is a hinged knee (where the articulation is linked like a hinge on a door). It can compensate for complete loss of the collateral ligaments, but it can also reduce the longevity of the implant and so should be used only as a last option. With removal of previous implants there is often a loss of bone from around the region of the removed implant. When a new implant is inserted a different design is frequently required to compensate for the bone loss. This may be in the form of a longer femoral stem or an acetabular augment for a hip replacement and a metal cone or stem for a knee replacement. If you have further questions regarding revision joint replacement I’d be happy to answer them during the consultation.