Edited by David W. Fitz, M.D., Assistant Professor, UW Orthopaedics & Sports Medicine
Characteristics of rheumatoid arthritis of the knee
As with any other joint in the body the knee joint can be destroyed by rheumatoid arthritis. This can lead to pain stiffness deformity and disability. Pain is typically aggravated by weight bearing activity. It often occurs at rest and interferes with sleep in later stages.
Incidence and risk factors
Knee involvement by RA is more common than hip involvement. Approximately 20-30% of patients with RA will have knees affected by this disease.
A thorough history will determine the patient's overall health and functional capacity. Examination of the spine hips knees ankles and feet for joint range of motion and deformity is done. Radiographs (X-rays) of the involved joints are obtained. These usually include neck X-rays in which the patient is first asked to bend their head forward then backward. Standard x-rays of the knees with the patient standing are obtained. Occasionally an MRI scan CAT scan (CT) or Bone-scan may be necessary.
In early stages of RA anti-inflammatory medications can be effective in decreasing pain and may slow the progression of joint destruction caused by RA.
Once joint destruction of the knee has set in there are no specific exercises that can stop or arrest the development of deformity and joint destruction. Regular range of motion exercises and weight bearing activity are important in maintaining muscle strength and overall aerobic (heart and lung) capacity and help prevent the development of osteoporosis which can complicate later treatment.
Possible benefits of knee surgery for rheumatoid arthritis
Surgery can reduce the pain and swelling caused by synovitis associated with RA and can correct the loss of cartilage and bony destruction associated with later stages of the disease.
Types of surgery recommended
Who should consider knee surgery for rheumatoid arthritis?
RA patients who have unrelenting knee pain and destructive arthritis of their knee joint that does not respond favorably to medical management should consider total knee replacement. RA patients with knee involvement in early stages who do not yet have destructive arthritis yet have pain and synovitis that does not respond to medical managementun should consider knee arthroscopy.
Not all surgical cases are the same, this is only an example to be used for patient education.
What happens without surgery?
The best case scenario includes inactivity and decreased mobility in conjunction with antirheumatic medication and intraarticular steroids can cause some improvement of symptoms.
A worst case scenario might be severe destruction of the knee joint and associated osteoporosis and reduced physical capacity potentially leading to a compromised knee replacement at a later stage with a less predictable outcome.
In early stages arthroscopic or open synovectomy can be of benefit. In later stages when the joint space has been destroyed bony destruction and deformity has occurred and knee stiffness has set in total knee replacement is the optimal and most reliable treatment.
Knee replacements in RA are extremely successful. More than 80% of patients will have a satisfactory result for 12-15 years.
Knee replacement surgery is an elective procedure and should be done only after non-surgical medical management has failed. Once indicated postponing the surgery for an extended period of time (months or years) only leads to increased disability disuse osteoporosis and skeletal complications that can make surgery more difficult and potentially compromise the final result.
Infection component failure and nerve damage are the most serious complications. Infection occurs in approximately 4% of patients with RA which is higher than in the osteoarthritis patient population. This is thought to be due to systemic immune compromise frail skin and impaired wound healing. Peroneal nerve injury can occur with correction of severely deformed knees. Postoperative stiffness is common and may be aggravated by generalized muscular weakness and disability.
These complications can necessitate a revision knee replacement. If an infection occurs then the prosthesis needs to be removed. A six week period of antibiotic treatment is needed and if the infection is cured a revision knee replacement can be done. Wound complications may require additional surgery. Nerve injuries are managed by special knee positioning and modified rehabilitation.
For the University of Washington systems please contact the Bone & Joint patient coordinators:
- Erin Kerber: (206) 598-6293
- Monette Manio RN: (206) 598-4288
Knee replacement in a patient with RA requires an experienced orthopedic surgeon with a strong total joint background and the resources of a large medical center. Patients with RA have complex medical needs and around surgery often require immediate access to a multiple medical and surgical specialties and in-house medical physical therapy and social support services.
Finding an experienced surgeon
- MEDCON (206) 543-5300
- American Academy of Orthopedic Surgeons: (800) 346 AAOS
- Washington State Medical Society: (206) 441-9762 (will connect to local County Medical Society)
A large hospital usually with academic affiliation and equipped with state of the art radiologic imaging equipment and Intensive Medicine Care Unit is clearly preferable in the care of patients with knee RA.
The knee joint will be exposed surgically by incising the quadriceps tendon and the inverting the knee cap. The joint surfaces are then excised and replaced with metallic femoral and tibial components cemented to the precut surfaces. A polyethylene liner is attached to the tibia component and the knee joint is closed.
An epidural anesthetic combined with a light general anesthetic is usually used.
Length of knee surgery for rheumatoid arthritis
Depending on the complexity of the case most surgeries last approximately 2 hours.
Recovering from Surgery
Pain and pain management
Analgesics administered through the epidural catheter placed for surgery are very effective for controlling postoperative pain and are used for approximately 48 hours. Patient controlled intravenous narcotics can be used as a substitute for or supplement to epidural analgesics. By the third postoperative day oral narcotics are usually sufficient for pain relief and are quickly tapered according to individual patient needs. After that oral narcotics are administered and provided for the first two to four weeks after the patient has been discharged.
These medications are very effective in relieving the pain associated with total hip replacement. Dryness in the mouth sleepiness lightheadedness and constipation are the most frequent side effects of narcotic medications. The most serious side effect is suppression of respiration.
The physical therapist starts with a rehabilitation program on day one post-surgery. Trained nurses observe the patient in the ward. The surgeon and the surgical team evaluate the surgical incision daily and the patient normally gets discharged on the 4th day. The epidural catheter and bladder catheter are normally removed within 24 to 48 hours.
Recovery and rehabilitation in the hospital
90% of recovery takes place within the first six weeks. Rehabilitation begins on the first postoperative day. It starts with sitting or standing at the bedside and progresses to walking with assistance and stair climbing. Knee range of motion is begun on the second postoperative day and is combined with quadriceps strengthening exercises. Instruction in the use of assistive devices is given.
The patient is discharged with oral narcotics to ensure comfort at home. Patients are usually ambulatory with a walker and independently mobilize from bed to walking. Physical activity and joint range of motion exercises are provided by the physical therapist. The patient is seen approximately two weeks after surgery to remove staples and stitches and to check the wound and to make sure the rehabilitation is going according to plan.
Most patients go home after 4 days in the hospital provided that there is someone to help them with the activities of daily living. If they do not have help at home then a short stay at a rehabilitation/convalescent facility will be necessary until they can resume independent living.
Daily active self directed exercise and regular supervised physical therapy is essential to achieve and maintain good range of motion and restore muscle strength and mobility in the first 6-8 weeks after surgery.
Physical therapy begins with the inpatient rehabilitation described above. After returning home physical therapy can continue with the therapist coming to the patients home or in the therapists office as needed. If the patient is unable to travel outside the home therapy at home can usually be arranged.
This therapy normally lasts 6-8 weeks and should be continued until the patient has a satisfactory range of motion and muscular strength is restored.
Returning to ordinary daily activities
Patients normally walk unaided by 6 weeks and can comfortably do normal activities at 3 months.
Long-term patient limitations
Patients are normally encouraged to remain active. Walking recreational biking and swimming or water aerobics are encouraged. Downhill skiing running and contact sports are discouraged.