Hip and Knee Surgery

The knee and the hip are major joints that we depend on for mobility. The knee serves as a hinge between the thigh and lower leg and also provides some rotation. The largest and one of the most complex joints in the body, the knee supports almost the entire weight of the body. The hip joint joins the femur (thigh bone) to the pelvis using a ball and socket joint. It supports much of the weight of the body and provides stability while moving and standing still. When the knee or hip is affected by RA, it can make mobility difficult or impossible and cause significant disability.

How RA affects the knee

Involvement in large joints, such as the knee, including inflammation, swelling, and stiffness  tends to occur in later stages of RA. The symptoms may be particularly challenging in the morning. Swelling with a build-up of synovial fluid and thickening of the lining of the synovium is particularly common with knee involvement. Both of these effects combine to make movement, particularly flexion (bending), difficult. Due to changes in the joint, ligaments (the fibrous cords that connect bone to bone or cartilage to cartilage and hold the joint together) may become lax. This can lead to the development of deformities and may cause the major muscles of the leg (such as the quadriceps in the thigh) to atrophy (to waste away and become weak). Swelling of the bursa behind the knee joint (bursitis) can also occur with RA.1,2

Surgery for the knee

If joint symptoms do not respond to medication or other management approaches, surgical interventions may be used. Surgical options for the knee include1,3:

  • Synovectomy to remove inflamed synovial lining
  • Total knee replacement (arthroplasty)

Synovectomy, which is typically performed arthroscopically (using thin instruments placed into the joint through small incisions), involves removal of part of the inflamed synovial lining.3

Total knee replacement may be used where there is severe damage to the joint and related structures. The main challenges in knee replacement in patients with RA include bone erosion and decreased bone mineral density, deformity, and soft tissue contracture, making flexion of the knee difficult. Bone grafting and other techniques can be used if bone is too weak or damaged to accept an artificial device. Various prosthetic options are available, depending on the nature and extent of knee damage.3,4

How RA affects the hip

Involvement in large joints, such as the hip, tends to occur in later stages of RA. RA can cause the synovium in the hip to swell, damaging the cartilage in the hip joint. As with other joints, RA can cause damage to joints on both sides of the body, and both hips may be affected. Hip involvement may cause pain in the groin, the upper outer part of the thigh, and/or the buttocks. Range of motion and general function of the hip are also impaired, and the damage to the hip from RA is visible on x-ray.5,6

Surgery for the hip

If joint symptoms do not respond to medication or other management approaches, surgical interventions to repair damage to the hip may be used. Surgical options include3,5:

  • Synovectomy to remove inflamed synovial lining
  • Total hip replacement

Synovectomy involves removal of some or all of the joint lining and may be used in cases where joint damage is limited to the lining and cartilage is still in tact.5

Total hip replacement is often used in RA and is effective in providing pain relief and improving motion. The main challenge in performing hip replacement in patients with RA is dealing with bone loss and low bone mineral density.3,5

Rehabilitation

Rehabilitation following hip and knee replacement surgery is crucial to a successful outcome. If you are having hip or knee replacement, work with your doctor and physical therapist to arrange a rehab plan. This plan will include a program of exercise and other interventions to help strengthen and heal the tissues around the prosthetic implant. Use of assistive devices for daily activities is also recommended as joint function is restored.1,3,4

Written by: Jonathan Simmons and Emily Downward | Last reviewed: June 2018.
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