by Dr. Richard Beauchamp, M.D., FRCSC
Joint replacement surgery, particularly of the hip and knee, has become one of the most frequently performed operations around the world. According to the American Academy of Orthopedic Surgeons, over 300,000 total hip replacements (THR) are completed in the United States every year, and the number of knee replacements is even higher.
The topic of joint replacements pops up frequently in conversation with older adults. A close relative of mine underwent THR several months ago and is now awaiting replacement of her other side. Her partner is having his knee replaced in the spring. At a recent Running Room weekly walk, I encountered a gentleman who had his hip resurfaced last year and now instead of running marathons, participates in triathlons. Lastly, a co-worker with osteoarthritis of the hip recently sought my input. She has been advised by her orthopedic surgeon to undergo a THR at age 45. As a recreational runner for the past 25 years, she wanted to know if she would be able to continue running after the joint replacement. Before I share my response, let’s have a closer look at the hip joint.
Anatomy of the hip
The hip is a ball-and-socket joint connecting the femur (thigh bone) to the pelvis. The “ball” of the femur is the femoral head, while the “socket” is a concave part of the pelvic bone, called the acetabulum. Normally, the hip joint is lined with smooth cartilage and receives lubrication (synovial fluid) from the lining of the joint (synovium). The joint capsule is made up of ligaments, which provide stability while allowing movement.
Onset of arthritis
The hip joint can be affected by several conditions that cause a loss of its smooth cartilage and its sphere-like shape, leading to poor contact between the femoral head and the acetabulum. Rheumatoid arthritis is an autoimmune condition that affects the synovium. Osteoarthritis (which can be hereditary) can lead to functional problems, pain and stiffness. Trauma or injuries can cause avascular necrosis (AVN) of the hip, resulting in bone death and loss
Is hip replacement surgery for you?
Arthritis is a fact of life. If you live long enough, you will get some form of arthritis. A joint replacement is not always needed, however; non-operative treatment may be sufficient for some people. This approach consists of maintaining muscle strength, proper body weight (to diminish excessive forces across the hip joint and reduce premature wear of the bone and cartilage) and using walking aids such as a cane. If all forms of non-operative methods fail, and there are no contraindications, then the alternative is a joint replacement.
Although THR is highly successful, some complications (such as infection) can arise. This may lead to the need for further surgery or even hip fusion. All artificial joints experience wear. With loss of microscopic particles from wear and tear, the body is exposed to metal and polyethylene elements. This can create a chronic inflammatory response leading to joint loosening and eventual failure. The wear factor is highest in men, in those with a high activity level, patients under age 50 and those with poor component alignment.
To accommodate younger and more active people seeking treatment for hip arthritis, some researchers have devised a resurfacing system where less of the femur is removed at the time of surgery and a metal covering is inserted over the femoral head. The thought is that it can be offered to younger patients and may make revision surgery more successful when needed in the future. There are some risks unique to this procedure that cause many surgeons to avoid using it.
Return to activity
There are no easy answers when a patient (such as my co-worker described above) asks “Can I continue to run on my new hip?” The surgeon doesn’t want to commit the patient to a completely sedentary lifestyle with all its associated health complications. Maintaining an active lifestyle is still important and light activities are preferred to avoid excessive weight transmission through the artificial joint. Some surgeons may advise against twisting activities, particularly early post-operatively, due to the particular hip replacement inserted, but generally non-impact activities like golf, skiing, walking and cycling are permitted. Some professional athletes have returned to high-level sport following hip surgery, but those are the exception rather than the rule. Patients are typically advised to proceed with “cautious activity” and to concentrate on lower impact activities. The goal is avoid a repeat THR (also called a revision), which is much more complicated for both the surgeon and patient.
Dr. Richard Beauchamp is an orthopedic surgeon based in Vancouver. He is the medical director of the Shriner’s Gait Lab at Sunny Hill Health Centre and a clinical professor in the Department of Orthopedics at the University of British Columbia. He is an avid runner and walker who has completed seven marathons.