Joint pain at the hip and knee is something many people experience, especially as they age. Where possible, non-invasive, conservative management of joint pain is the first choice of treatment, especially exercise. However, in cases where treatment options such as medication, physiotherapy and lifestyle changes have failed to manage pain and increase function, then surgery may be the best option. The most common reasons for a joint replacement are osteoarthritis, rheumatoid arthritis or deformed joint, usually congenital (from birth).
A joint is where two bones connect to form movement, but not all joints are the same. The knee is known as a hinge joint and allows the movement of flexion and extension, whereas the hip joint is known as a ball and socket joint and allows the movements of flexion, extension, abduction and adduction. Depending on the damage to the joint, your surgeon may either suggest a total joint arthroplasty or a hemi-arthroplasty. Arthroplasty literally means the surgical repair of a joint—arthron=joint or articulation; plasty =moulding, grafting, or formation of a specified part.
The first joint replacement on a human was performed some eighty years ago, and in 1947 a surgeon called Stephen S. Hudack operated on a 38-year-old woman who had a tumour in her upper leg, replacing her hip joint with a plastic one. Her only option at that time was an amputation but, thanks to Dr Hudack, she did not lose her leg and was reported to be walking around with no compromise of her hip joint. Since that time the materials used and the procedures have changed but the objective is the same, to allow someone to move around pain-free. The most common joints that are replaced are hip, knee and shoulder but it is also possible to replace the ankle, elbow and wrist joints.
Hip replacements can either be total or hemi (that is where only part of the joint is replaced, usually the head of the femur. The hip is the largest joint in the body This ball and socket joint is formed by the head of the femur which fits into the acetabulum, a cup-like shape on the pelvis. In a total hip replacement both the head of the femur and the acetabulum are replaced with a prosthesis. The most common reasons for a hip replacement are pain and stiffness usually associated with osteoarthritis, rheumatoid arthritis, injury or fracture. Other less common causes are avascular necrosis (usually the result of an injury that leads to a disruption of the blood supply to the head of the femur, causing the bone to weaken and crumble) and childhood hip disease or congenital problems.
Knee replacements, like the hip, can be total or hemi. The knee is made up of three parts, the medial compartment (inner part of knee), the lateral component (the outside of the knee) and the patellofemoral joint. Depending upon the area of damage, a total or hemi replacement may be recommended. A total knee replacement involves replacing both sides of the femur and the shinbone, whereas a partial knee replacement is a replacement of either the medial or lateral aspects and in some cases maybe just the patella. The main indicators for surgery are usually knee pain exacerbated by walking and tasks like negotiating stairs.
Shoulder replacements are not as common as hip and knee replacements. The first surgeries were performed to treat severe shoulder fractures but, over time, they have also become a treatment option for painful shoulders caused by arthritis. The shoulder joint is made up of the humerus (upper arm bone), scapula (shoulder blade) and clavicle (collarbone). The humerus and the scapula form the glenoid joint and the scapula and collarbone form the acromioclavicular joint. Surgery can either replace just the head of the humerus (known as the ball) or in some cases both the ball and socket (the glenoid) The treatment options are either replacement of just the head of the humerus bone (ball), or replacement of both the ball and the socket (glenoid surface of the scapula).
Less common replacements are at the wrist, fingers, ankle and elbow. Despite being a choice for relieving pain and improving function, there are often complications and restrictions. The hope is that after surgery people will return to the life they led before pain but even when these operations are successful, they often leave the person with restricted range which can limit some of their daily activities. The most common complications are infection, blood clots, nerve injury and the loosening or dislocation of the prosthetic joint.
There are also minimal risks associated with surgery but these are often outweighed by the benefits. In order to maximise the benefits of surgery, most patients are referred to a physiotherapist who will focus on relieving the painful after-effects of surgery and increasing joint range, muscle strength and function. It is not uncommon to have developed bad movement patterns prior to surgery; physiotherapists are skilled at analysing movement and have a range of skills and interventions to help people maximise their potential.
