Life-Changing Procedures Now Routinely Performed by Hip Specialists
There can be few things more debilitating than to be in constant pain. It can make it hard to focus on everyday tasks and put an end to any hope of a good night’s sleep. Painkillers may provide some relief, but there is invariably a risk of unpleasant side effects when required to take prescription medications over a prolonged period – not to mention the possibility that one might develop a dependency. In practice, such would be the probable fate of many more of those who suffer from chronic pain if it were not for the surgical interventions now undertaken by the hip specialists of today.
Over the course of a lifetime, our joints take a pounding, especially those required to support the full weight of our bodies when standing, walking, or running. Normally, where two or more bones articulate, their surfaces are protected from direct contact by a smooth cushion of cartilage. Additional protection is provided by a fluid-filled membrane that encloses the components of the joint to ensure that they are well lubricated. Conditions that might disturb these protective mechanisms will result in increased friction, which can lead to damage to the bone surfaces, resulting in pain and possible reduced mobility. Osteoarthritis is one such condition and sufferers might once have faced a lifetime of pain and confinement to a wheelchair. Today, hip specialists are now able to repair most forms of damage to this hard-working joint and, should the damage prove to be too severe, they can even replace part or all of this joint with prosthetic components.
Articulation in this joint, one of the largest in the body, is by means of a ball-and-socket action in which the head of the femur represents the ball, while the acetabulum forms the socket into which it fits. Damage to the coating of cartilages on either surface, whether due to physical injury or disease, will require repair if the joint is to function normally. Where only the head of the femur is affected, hip specialists will often only replace this. This procedure is known as hemiarthroplasty or partial hip replacement. For those patients who present with more extensive damage, in which the acetabular surface is also affected, they will, instead, perform a total hip arthroplasty (THA). In each case, the results can be life changing – relieving patients of pain, restoring mobility, and returning their independence.
To perform a partial hip replacement, specialists must first remove the femoral head and a portion of the shaft. In the early days of this procedure, a prosthesis fashioned from an alloy of cobalt and chrome would then have been bolted to the resected shaft. Since then, however, it has become the preferred practice to insert the implant into the medullary canal of the femur, thus allowing the bone to grow through holes in the inserted portion and securing the implant more naturally.
For a total replacement, damaged bone and cartilage are removed from the acetabulum, which is then fitted with a cup made of metal or polyethylene. Metal cups are porous on the outside and secured by bone growth, and require a plastic liner to prevent friction, while hip specialists must employ special cement in order to secure the polyethylene version. There are several variations on this procedure, which may also use alternative combinations of materials to form the replacement joint. The metals used include stainless steel, chromium, cobalt, and titanium, and the type of articulation may be either metal on metal (MOM) or metal on polytheylene (MOP).
More recently, the introduction of ceramics as an alternative to metals has given hip specialists the additional options of ceramic on metal (COM), ceramic on ceramic (COC), and ceramic on polyethylene (COP). The choice is largely determined by clinical indications, but cost may also play a role. All prosthetic joints are prone to varying degrees of long-term wear, so the age of the patient determines the required longevity of the prosthesis and the best materials to use. Whatever the choice, however, all have been designed to minimise the risk of any adverse reactions by the body in response to the presence of a foreign substance.
Since the first tentative attempts at these procedures, hip specialists have perfected new surgical techniques making it possible, in some cases, to perform total and partial replacements by means of minimally invasive procedures that help to limit the risk of excessive, bleeding and infection, whilst also reducing the required post-operative recovery period.