Joint ventures

    31 May 2014

    Having bad arthritis is miserable, and it affects every part of people’s lives. As an orthopaedic surgeon, I sit in hospital clinics talking to people about their options, and whether joint replacement surgery is right for them. Hip or knee surgery for arthritis changes people’s lives, but it is not for the faint-hearted.

    When the lining of hips or knees starts to wear out, the joints become painful. Joint aches and pains affect a large proportion of the over-50s, and some degree of wear and tear is part of the normal process of getting older. Once arthritis becomes severe, however, it has a really big impact on your quality of life, limiting your ability to walk, get up and down stairs and get a full night’s sleep. It is people in this category who will benefit most from a joint replacement.

    Why do people get arthritis?

    There are many different types of arthritis, but osteoarthritis is by far the most common. Osteoarthritis is wear and tear of the white, smooth, shiny cartilage which lines the inside of our joints, allowing the surfaces to glide smoothly and without pain. Broadly, arthritis affects people in proportion to how long they have lived, and how heavy they are: the more steps you have taken in your life, and the more weight supported in each step, the higher the chance of the joint wearing out. It is thought that there is probably a genetic predisposition as well. In addition, younger people who have injured themselves, or who have an unusual degree of knock knee or bow-leggedness, can develop osteoarthritis of their knees because of the unevenness of load-bearing through the joint. Young people’s hips can become arthritic if they have an abnormally shaped hip joint (rather than a smooth ball and socket) or if they have a medical condition which affects the blood supply to the femoral head, causing the ball part of the joint at the top of the thigh bone to crumble.

    What happens inside the joint?

    Cartilage is a bouncy shock absorber. The structure is held together by proteins, which give form and substance to a gel of sugar molecules and water. Once the intricate structure becomes damaged, it starts to break up into fragments. This means that the cushioning effect is lost, and the bone beneath begins to feel the strain more, which is painful.

    What are the options for treatment?

    Broadly the options are either tablets to help with the pain, sometimes in conjunction with periodic injections of local anaesthetic and steroids into the joint which can provide temporary relief for a few months, or surgery to replace the worn-out joint surfaces. Paracetamol, codeine and ibuprofen are all good for arthritis pain, although it is probably best to take the first two regularly, and the ibuprofen just occasionally, depending on the severity of pain. People might choose the former if their arthritis pain is not too severe, or if they have multiple other illnesses that might make major surgery too risky. There are lots of tablets and supplements available for arthritis on the market. They tend to be heavily marketed and expensive, and I tell my patients to save their money.

    Should sufferers avoid activity?

    No. If the process of arthritis is already under way, you cannot reverse it. To get the best out of your legs, either living with an arthritic joint, or after a joint replacement, it is crucial to keep the whole leg strong and flexible, so keep walking or doing whatever sport you can, keep the muscles strong and make sure you can get the joint straight as well as fully bendable. Take painkillers before exercise. Low-impact activities such as cycling or swimming will be the least painful and easiest to keep up.  Physiotherapists can advise on exercises.

    How are joints replaced?

    Hip replacement

    Both the worn-out ball and the worn-out socket of the hip are replaced. The surgery takes about an hour and a half, and leaves a scar on the side of the hip roughly eight or nine inches long. You can have this operation either under general anaesthetic, or a spinal anaesthetic, which means you are numb from the waist down. The top of the thigh bone is removed, and a length of metal (called the femoral stem) is inserted into the bone, with the new ball on top of it. This is normally made of metal, but could be ceramic. The socket in most cases will be made of plastic, but there are other options such as metal sockets or ceramic sockets. Both parts are traditionally fixed into your own bone using specialised medical cement, which acts as a grout.

    Knee replacement

    In a normal knee, the bottom end of the thigh bone (femur) and the top end of the shin bone (tibia) are coated by articular cartilage, allowing one to move against the other smoothly. There is another joint — the one between the back of the kneecap and the front of the end of the femur. Along with some  ligaments, these two joints comprise the knee. In knee replacement, the worn-out surfaces of the ends of the bones are removed and recapped with replacement pieces, made from stainless steel and plastic. You will have a long scar. Some surgeons also recap the back of the knee cap (patella resurfacing), although many do not. Not resurfacing the knee cap doesn’t seem to lead to problems, and is a definite advantage if you have to have your knee redone in the future.

    What are the risks?

    Joint replacements wear out over time. This is why it is not a good idea to have a joint replacement when you are young, if you can help it. Replacement joints might  last 15 to 25 years, and each time it needs to be done again it is more difficult.

    The risks of hip replacement (see below) are serious, but unlikely. We go to great lengths to avoid them — for example having special air flow systems in the operating theatre to reduce the chance of infection.

    • Bleeding (occasionally requiring a blood transfusion)
    • Dislocation (the new hip coming out of the socket)
    • Deep vein thrombosis and pulmonary embolism (blood clots)
    • Infection (usually superficial, occasionally deep, which is more serious)
    • Damage to nerves and blood vessels (very unlikely)

    Having said that, nine out of ten patients who have a hip replacement will not have any problems and are very happy with their decision. It is not uncommon for patients to forget which side they have had replaced.

     Knee replacement is an excellent operation, although on average, patients are slightly less happy with it than with hip replacements. The major risks are the same for hip replacements.

    How quick is recovery?

    All being well, after a joint replacement you should be able to stand up and put your full weight on the new joint as soon as you are fully awake. The first couple of days you will need very strong painkillers. Physiotherapists will begin helping you to walk, usually using crutches, and teach you to negotiate a staircase safely. You will be advised of what activities and positions to avoid initially. If you are quite fit, you might go home on the fourth or fifth day, probably still using crutches for support. By six weeks, when you will be seen in a clinic, you should be able to walk normally. In general, it takes slightly longer to rehabilitate after a knee replacement — I tell people they won’t be happy they have had it done for about three months. A crucial mistake is to believe that the operation cures the problem. Actually it is just the first step, which takes away the pain of the arthritis, but the hard work of getting back to normal is down to the patient and how hard they work on their muscle strength and flexibility. Push through the pain — it will be worth it to get your life back.