Osteoarthritis (OA) is the most common joint disease, causing severe pain due to joint inflammation (synovitis). While total knee arthroplasty (TKA) is commonly performed to reduce pain, 20% of patients are dissatisfied with their outcome post-surgery. This dissatisfaction is caused by persistent pain post-TKA due to synovitis that is not routinely removed during surgery. To address this problem, a synovectomy can be performed during TKA, which involves resecting the inflamed layer of tissue lining the joint, called the synovium, and its associated sensory nerve endings. Since the synovium will regenerate in the months post-surgery, synovectomy only transiently reduces pain after TKA. The proposed study will help ascertain the benefits and effects of synovectomy in patients who are more likely to experience poor satisfaction (driven mostly by pain) post-TKA. This study will include 62 patients undergoing TKA due to end-stage OA who have moderate to severe synovitis, as determined by ultrasound assessment. Patients will be randomized (1:1) to undergo a TKA with synovectomy or without synovectomy. Primary and secondary outcomes will be assessed through patient-reported levels of pain and function, results from physical performance tests, and quality of life (QOL) scores. These measures will be recorded pre- and post-surgery for comparison. Through demonstrating that synovectomy can at least transiently reduce pain post-TKA, this study will provide evidence for the development of medical therapies that target the synovium to slow its regrowth. This will be transformative for the long-term management of joint pain and synovitis post-surgery, thus significantly improving patients' overall QOL.

Inclusion Criteria:

1. Males or females over the age of 40 diagnosed with knee osteoarthritis
2. Scheduled for first unilateral total knee arthroplasty
3. Moderate to severe (at least grade two) synovitis and synovial hyperplasia, as determined by ultrasound assessment
4. Referred to the Pre-Admission Clinic at University Hospital

Exclusion Criteria:

1. Bilateral, uni-compartmental, or revision total knee arthroplasty
2. Osteoarthritis due to genetic syndromes (e.g., Ehlers-Danlos Syndrome, etc.)
3. Known inflammatory arthropathy, another rheumatic disease, or disease-modifying anti-rheumatic drug (DMARD) use (e.g. methotrexate, hydroxychloroquine, sulfasalazine, leflunomide, TNF inhibitors, etc.) - note: Gout is NOT an exclusion
4. Joint injection (steroid or viscosupplement) within 12 weeks of Pre-Admission Clinic appointment date
5. Cannot read, write, or understand English (printed instructions are provided in English only)
6. Any factors precluding patients from attending follow-up appointments (e.g., socio-economic limitations, distance from clinic, no access to home/cell phone, etc.).
7. Cognitive impairment or psychological problems that preclude the ability to understand instructions
8. Not able to follow up at routine standard of care post-operative visits