5 questions with a doc: Hip and knee arthritis and treatment

Dr. Jason Desmarais of Concord Orthopaedics discusses arthritis of the knees and hips, as well as available treatment options.

What is arthritis?

Arthritis is the deterioration of the cushion in your joints. It results from wear and tear, or osteoarthritis, or when the autoimmune system attacks the joint lining, known as rheumatoid arthritis. Arthritis is very common, affecting 70 million people in the United States, and osteoarthritis accounts for 90% of cases.

How is osteoarthritis treated?

Osteoarthritis treatment falls into three categories: non-pharmaceutical interventions, pharmaceutical interventions and surgery. Non-pharmaceutical options include exercises, physical therapy and weight loss education. Pharmaceutical interventions include medications like anti-inflammatory drugs, joint injections and topical treatments. If and when both of these types of interventions fail, joint replacement surgery is considered. Luckily, total joint replacement is both cost and medically effective.

What happens in a total hip replacement?

A total hip replacement works by first removing the diseased area in the hip socket and reshaping it. A new cup made of metal is secured in the socket and a plastic liner is placed within the cup. A metal stem is inserted into the femur and a ball, usually ceramic, is placed on the stem and positioned into the cup. A biologic bond forms between the implant and the bone six to eight weeks after surgery, further securing it in place. Today, an anterior, or frontal, approach to the surgery is often used. This affords benefits to the patient including being less invasive, faster recovery times, less pain, likely lower dislocation rates and likely more accurate leg lengths. These benefits are possible because this approach allows the surgeon to work between the muscles and tissues with minimal or no detachment from the bones, and is nerve-sparing. A high-tech surgical table and intraoperative X-ray are used to accomplish this. After surgery, the need for rehabilitation and physical therapy are rare. The patient is able to walk right away with assistance. Patients are required to walk for five minutes every other hour during the day for the first couple of weeks, after which the active time increases to 20 minutes. The expectation is that the incision heals after two to three weeks and the patient returns to normal activities in two to three months. Relatively normal walking is seen at one to two months post-surgery.

What is involved in a total knee replacement?

The anatomy of the knee is quite different from the hip, which is a ball and socket joint. The knee is referred to as a hinge joint because it can bend and straighten. It involves three bones: the tibia, or shin bone, the femur, or thigh bone, and the patella, or kneecap. In an arthritic knee, wear and tear deteriorates the natural cushion that exists between the bones, leading to bone-on-bone contact, pain, stiffness, and swelling. Unlike a total hip replacement, a knee replacement is somewhat of a misnomer because in reality we do not take out the whole knee. The procedure involves resurfacing the ends of the tibia and femur, removing any diseased bone and cartilage and replacing them with implants. Four components are involved: the femoral component, tibial component, the polyethylene insert and the patellar component. The femoral component caps the thigh bone, the tibial component caps the shin bone, the polyethylene insert is placed between these two as a cushion, and the patellar component replaces the kneecap cartilage. We always leave the kneecap itself, though usually resurface the cartilage. Although total recovery time is similar to a hip replacement, a knee replacement involves quite a bit of physical therapy and rehabilitation.

How do you know if you are a candidate for either of these surgeries?

If you are in a lot of pain and it is affecting your quality of life or preventing you from performing basic activities, consult a physician. Early diagnosis is important, as osteoarthritis is degenerative and will not get better. Hip and knee pain could also be the result of a number of other issues including fractures, labral tears, spine pathology, ligament injury, tendonitis or bursitis. Hip dysplasia can cause hip pain and a meniscus tear, and muscle weakness or imbalance can stem from knee pain. Interestingly, one potential cause of knee pain is ipsilateral hip disease, where the hip is riddled with arthritis but all pain is referred to the knee. This requires a hip replacement, even though the chief patient complaint is a painful knee. Both surgeries require a certain level of patient health. Patients must quit smoking, achieve a healthy weight, have diabetes under strict control, have a stable mental health condition and exhibit good oral hygiene. Having a good support system in place is also incredibly important. All need to be achieved or in place to improve post-operative outcomes and reduce the risk of complications.

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Dr. Jason Desmarais, M.D. spoke about hip and knee arthritis at the January Concord Hospital Trust “What’s Up Doc?” Donor Lecture Series. The monthly series, supported by the Walker Lecture Fund, features members of Concord Hospital’s medical staff speaking to donors about new and innovative medical treatments and services. Watch the presentation at youtube.com/concordhospital.