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 (especially in the morning) tends to occur in later stages of RA. 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) to atrophy (to waste away and become weak). Swelling of the bursa behind the knee joint (a condition called a Baker’s cyst or popliteal cyst) can also occur with RA. In some cases, the cyst may rupture and extend down the calf.1

 

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 include2,3:

  • Synovectomy to remove inflamed synovial lining
  • Osteotomy (removal of bone) to improve alignment of knee
  • Total knee replacement

 

Synovectomy, which is typically performed arthroscopically, involves removal of part of the inflamed synovial lining.2

Osteotomy may be used in cases where the RA disease process has resulted in erosion of bone and damage to cartilage, resulting in misalignment of the knee. In osteotomy, the tibia (shin bone) or femur (thighbone) are cut to correct the alignment of the knee.2

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

 

How RA affects the hip

Involvement in large joints, such as the hip, tends to occur in later stages of RA. Only 10% of patients who have been diagnosed with RA for less than 10 years will experience hip involvement. However, 40% of patients with a longer history of RA may develop problems affecting the hip. Hip involvement may be difficult to detect, as swelling may not be evident on physical examination. Up to half of patients with RA-related hip disease may not experience any symptoms. Others may complain of stiffness and limited range of motion, as well as pain in the groin or the inside of the knee.1,4

 

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

 

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.3

Written by: Jonathan Simmons | Last reviewed: September 2013.
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