Rheumatoid Arthritis of the Knee
Rheumatoid arthritis of the knee is an autoimmune condition in which the immune system attacks the knee joint lining, causing inflammation, cartilage destruction, and bone erosion. Mr Shakir Hussain, Consultant Orthopaedic Surgeon at the Royal Orthopaedic Hospital Birmingham, treats advanced rheumatoid arthritis of the knee with robotic total knee replacement when medical therapy no longer controls joint damage.
What is rheumatoid arthritis of the knee?
Rheumatoid arthritis of the knee is an autoimmune inflammatory disease in which the body's immune system mistakenly attacks the synovial lining of the knee joint. Unlike osteoarthritis, which results from mechanical wear, rheumatoid arthritis is driven by chronic immune-mediated inflammation that destroys cartilage, erodes bone, and can damage the surrounding ligaments and tendons if not adequately treated.
In a healthy knee, the synovium is a thin membrane that produces lubricating fluid, allowing smooth, painless movement. In rheumatoid arthritis, the synovium becomes chronically inflamed and thickened, a process called synovitis. The inflamed tissue releases destructive enzymes and immune factors that progressively erode both the cartilage and the underlying bone, leading to joint deformity over time.
A defining feature of rheumatoid arthritis is that it attacks all three compartments of the knee simultaneously, in contrast to osteoarthritis, which typically begins in the medial (inner) compartment. It also commonly affects both knees symmetrically, and is accompanied by systemic features such as fatigue, malaise, and involvement of other joints throughout the body.
Modern rheumatology has transformed the outlook for patients with RA. Biological therapies and targeted synthetic DMARDs, when started early and maintained consistently, can substantially slow or halt joint destruction in the majority of patients. Surgery is reserved for those in whom medical therapy cannot adequately control joint damage or restore function.
What are the symptoms of rheumatoid arthritis of the knee?
Rheumatoid arthritis of the knee typically causes symmetrical swelling and warmth in both knees, persistent pain at rest and with activity, and morning stiffness lasting more than one hour. These features, combined with systemic fatigue, distinguish RA from osteoarthritis, where stiffness rarely exceeds 30 minutes and systemic symptoms are absent.
Symptoms of RA often fluctuate in intensity. Periods of active inflammation, called flares, alternate with periods of relative remission. Over time, without adequate disease control, the cumulative damage from repeated flares leads to progressive joint destruction and deformity.
Symmetrical joint swelling
Both knees are typically affected at the same time and to a similar degree, a hallmark that helps distinguish rheumatoid arthritis from the asymmetric, compartment-focused pattern of osteoarthritis.
Morning stiffness over one hour
Prolonged morning stiffness lasting more than one hour before easing with movement is a characteristic feature of inflammatory arthritis and is used as a diagnostic criterion by rheumatologists.
Warmth and redness over the knee
Active synovitis causes the overlying skin to feel warm and appear red, reflecting the increased blood flow driven by chronic inflammation within the joint.
Persistent pain at rest and with activity
Unlike osteoarthritis, where pain is predominantly mechanical and eases with rest, rheumatoid arthritis pain is present at rest as well as during activity, particularly during flares.
Systemic fatigue and malaise
Rheumatoid arthritis is a systemic disease. Patients frequently report significant fatigue, general unwellness, and a reduced capacity for everyday activities, which are driven by the inflammatory process itself.
Progressive deformity and loss of function
Over years of inadequately controlled disease, bone erosion and ligament damage lead to visible knee deformity, reduced walking distance, and increasing dependence on aids.
What causes rheumatoid arthritis?
Rheumatoid arthritis results from a misdirected immune response in which the body attacks its own synovial tissue. The precise trigger is not fully understood, but genetic susceptibility (particularly the HLA-DR4 marker), female sex, smoking, and environmental factors all contribute. RA is approximately three times more common in women and typically presents between the ages of 40 and 60.
Rheumatoid arthritis is not caused by wear and tear or injury. It is an autoimmune condition, meaning the immune system targets the body's own tissues. In RA, the primary target is the synovial membrane lining the joints. The risk factors that predispose to RA include:
- Genetic susceptibility. The HLA-DR4 genetic marker is present in approximately 70 per cent of patients with seropositive RA. Having a first-degree relative with RA increases personal risk two to threefold.
- Female sex. RA is approximately three times more common in women than in men. Hormonal factors are thought to contribute, as disease onset often occurs in the peri-menopausal years.
- Smoking. Smoking is the most clearly established environmental risk factor for RA, increasing risk by two to three times, and is associated with more severe and erosive disease.
- Age 40 to 60 at onset. While RA can occur at any age, including childhood (juvenile idiopathic arthritis), peak incidence in adults is between the ages of 40 and 60.
- Microbiome and gut health. Emerging evidence links alterations in the gut and oral microbiome with triggering or perpetuating the autoimmune response in genetically susceptible individuals.
How is rheumatoid arthritis of the knee diagnosed?
Diagnosis relies on blood tests, including rheumatoid factor (RF) and anti-CCP antibodies, combined with imaging. X-rays show periarticular osteopenia, joint-space narrowing, and marginal erosions. MRI detects synovitis and bone marrow oedema before erosions are visible on X-ray. Diagnosis is made by a rheumatologist and confirmed by meeting the 2010 ACR/EULAR classification criteria.
Suspected rheumatoid arthritis should be assessed promptly by a rheumatologist, as early treatment dramatically reduces long-term joint damage. Key investigations include:
- Rheumatoid factor (RF) and anti-CCP antibodies. Anti-CCP (anti-cyclic citrullinated peptide) is highly specific for RA and is often positive years before symptoms develop. RF is less specific but supports the diagnosis when positive alongside clinical features.
- Inflammatory markers (CRP and ESR). These confirm the presence of active systemic inflammation and are used to monitor disease activity and treatment response over time.
- Full blood count and other bloods. Anaemia of chronic disease is common. Liver and renal function tests are taken before starting certain DMARDs.
- Weight-bearing knee X-rays. Early films may be near-normal or show periarticular osteopenia only. Advanced disease shows joint-space narrowing across all three compartments, marginal erosions, and deformity.
- MRI of the knee. Detects synovitis, bone marrow oedema, and erosions earlier than X-ray, and is valuable for assessing disease activity and guiding treatment decisions.
Medical management of rheumatoid arthritis
The cornerstone of rheumatoid arthritis treatment is disease-modifying anti-rheumatic drugs (DMARDs), managed by a rheumatologist. Modern therapy, including methotrexate and biological agents, has transformed outcomes and substantially reduced the need for joint replacement surgery in patients whose disease is diagnosed and treated early.
Medical management is the primary treatment for rheumatoid arthritis and is led by a rheumatologist, not an orthopaedic surgeon. The key classes of treatment include:
- Conventional DMARDs. Methotrexate is the anchor DMARD for most patients and is started promptly after diagnosis. Other conventional DMARDs include hydroxychloroquine, sulfasalazine, and leflunomide. These drugs modify the disease process rather than just controlling symptoms.
- Biological DMARDs. Anti-TNF agents (etanercept, adalimumab, infliximab) and other biologicals (tocilizumab, abatacept, rituximab) target specific immune pathways driving inflammation. They are used when conventional DMARDs have not achieved adequate disease control.
- JAK inhibitors. Targeted synthetic DMARDs (tofacitinib, baricitinib, upadacitinib) block intracellular signalling pathways and offer an oral alternative to biological therapy for patients who cannot tolerate injections.
- Corticosteroids. Oral or intra-articular corticosteroids are used as bridging therapy during flares or when starting DMARDs, providing rapid symptom relief while waiting for disease-modifying treatments to take effect.
- Physiotherapy and occupational therapy. Exercise programmes designed for inflammatory arthritis protect joint function, reduce fatigue, and help maintain independence. Occupational therapists provide aids and adaptations to support daily living.
Mr Hussain works closely with the rheumatology team at the Royal Orthopaedic Hospital. Pre-operative rheumatology review is essential for any patient with RA approaching knee replacement surgery, to optimise disease control and plan the safe cessation of biological agents around the time of the operation.
When is knee replacement needed for rheumatoid arthritis?
Knee replacement is considered when medical therapy is optimised by the rheumatology team but significant joint destruction remains, causing substantial pain and functional limitation that conservative measures cannot adequately control. A pre-operative rheumatology review is essential to optimise disease control and plan the safe cessation of biological therapies around surgery.
The threshold for surgery in rheumatoid arthritis is similar to that for osteoarthritis: persistent pain that substantially affects quality of life, reduced walking ability, and failed conservative management. However, several considerations are specific to RA patients:
- Biological therapy must be paused before and after surgery to reduce infection risk, in line with national guidelines from the British Society for Rheumatology.
- Ligament integrity may be compromised by longstanding synovitis, influencing the choice of implant constraint level at surgery.
- RA patients have higher baseline infection risk due to both the disease itself and immunosuppressive medications; careful pre-operative optimisation is essential.
- Anaemia, a common finding in active RA, should be corrected before elective surgery to reduce transfusion requirements.
- Cervical spine involvement in RA must be assessed before general anaesthesia, as atlantoaxial instability is a recognised complication that influences airway management.
Private consultations with Mr Hussain are available at the Royal Orthopaedic Hospital, Priory Hospital Edgbaston, and Harborne Hospital. See the private consultation and surgery fees page for self-pay pricing and insurer information, or book a consultation directly.
Total knee replacement for rheumatoid arthritis
Total knee replacement is the standard surgical treatment for advanced rheumatoid arthritis of the knee, because all three compartments are typically affected. Robotic-assisted surgery helps optimise alignment and implant positioning even in knees with pre-existing deformity, and constraint level is matched to the patient's ligament integrity at the time of surgery.
Because rheumatoid arthritis damages all three compartments of the knee simultaneously, partial (unicompartmental) knee replacement is not suitable for most RA patients. Total knee replacement resurfaces all arthritic surfaces and provides reliable, long-lasting pain relief.
Total Knee Replacement
All three compartments are resurfaced with a metal femoral component, a tibial baseplate with a polyethylene insert, and patellar resurfacing where indicated. Constraint level (the degree of built-in stability in the implant design) is selected based on ligament integrity assessed at the time of surgery.
- Suitable for all three compartments affected by RA
- Robotic-assisted (MAKO, ROSA, CORI) for precise alignment in deformed knees
- Constraint matched to ligament integrity at the time of surgery
- Pre-operative biological therapy cessation planned with rheumatology
- Modern implants with a 20 to 25 year expected lifespan
Working with Your Rheumatologist
Mr Hussain works alongside the rheumatology team at the Royal Orthopaedic Hospital Birmingham to ensure that patients with RA approaching surgery are medically optimised. Biological therapy is paused pre-operatively in line with British Society for Rheumatology guidance, and resumed once wound healing is confirmed.
- Pre-operative rheumatology review arranged as standard
- Biological therapy cessation timed to minimise infection risk
- Cervical spine assessment where atlantoaxial instability is a concern
- Anaemia and disease activity optimised before surgery
- Post-operative rheumatology follow-up to restart medications safely
How successful is knee replacement for rheumatoid arthritis?
Total knee replacement for rheumatoid arthritis provides reliable and durable pain relief. National Joint Registry data shows approximately 90 per cent of total knee replacements are still functioning at 15 years. Patient satisfaction after knee replacement is approximately 80 to 85 per cent. With modern biological therapies slowing joint destruction, patients who do reach surgery typically achieve excellent outcomes.
Outcomes after total knee replacement for rheumatoid arthritis are comparable to those for osteoarthritis when patients are medically well prepared. The key determinants of a good outcome are adequate disease control in the peri-operative period, correct implant selection, and precise surgical technique. Robotic-assisted surgery, in which Mr Hussain holds certifications on three platforms, improves implant positioning accuracy even in knees with pre-existing deformity from RA.
Expertise in rheumatoid knee treatment in Birmingham
Consultant at the Royal Orthopaedic Hospital
Mr Hussain practises at the Royal Orthopaedic Hospital Birmingham, one of the largest specialist orthopaedic hospitals in Europe, alongside Priory Hospital Edgbaston and Harborne Hospital.
3,000+ arthroplasty cases
From a total of more than 5,000 procedures performed, giving the operative volume and case complexity required for consistently excellent outcomes. Read more about Mr Hussain's training and background.
MAKO, ROSA, and CORI robotic certifications
Mr Hussain holds certifications on all three major robotic knee replacement platforms, allowing robotic-assisted surgery to be offered to all suitable patients regardless of which platform is available at their chosen hospital.
Complex revision surgery expertise
Mr Hussain performs revision knee replacement for patients whose primary replacement has failed, including for infection, loosening, and instability. See revision knee surgery for more information.
Doctify Outstanding Patient Experience 2024, 2025, and 2026
Awarded in three consecutive years, recognising consistently high patient-reported outcomes and communication throughout the surgical journey.
4.98 out of 5 from verified reviews on Doctify. Outstanding Patient Experience Award 2024, 2025, and 2026.
Frequently asked questions about rheumatoid arthritis of the knee
For more questions about surgery, recovery, fees, and what to expect, see the full frequently asked questions page or read recent patient testimonials.