Knee synovectomy is an arthroscopic or open operation to remove inflamed or diseased synovial lining from the knee joint. It is performed for inflammatory arthritis, PVNS (pigmented villonodular synovitis), and synovial chondromatosis.
Arthroscopic: performed through standard portals using motorised shavers to remove the thickened, inflamed synovium from all compartments of the knee. Multiple portals may be needed for thorough access. Open: a larger incision allows more complete removal for diffuse disease. The operation takes one to two hours.
Synovectomy is recommended for PVNS causing recurrent bloody effusions, synovial chondromatosis with loose body formation, and refractory inflammatory arthritis (rheumatoid) not controlled by modern biological medications.
For inflammatory arthritis: optimisation of disease-modifying medications is the primary treatment. For PVNS: observation for mild disease. Radiosynovectomy (injection of radioactive substance) as an adjunct.
MRI to assess extent of synovial disease. Blood tests. Standard pre-assessment.
Reduction in swelling, pain, and recurrent effusions. For PVNS, removal of abnormal tissue prevents joint damage, though recurrence is common with diffuse disease.
Diffuse PVNS has 20–50% recurrence rate.
Common after extensive synovectomy.
Prolonged knee effusion.
Bleeding into the joint.
Joint infection.
With extensive open synovectomy.
From aggressive debridement.
General or spinal anaesthesia.
Weight-bearing as tolerated. Intensive physiotherapy to prevent stiffness. Ice and compression for swelling. Full recovery four to twelve weeks. Long-term monitoring for recurrence.
Reviews at two weeks, six weeks, and three months. MRI surveillance for PVNS — at least five years.
Localised PVNS has a low recurrence rate. Diffuse PVNS has a high recurrence rate (up to 50%) and may require repeat surgery, radiotherapy, or emerging targeted medications such as pexidartinib.