Diffuse pigmented villonodular synovitis is a challenging disease to treat because of extensive soft tissue proliferation, bone infiltration and extra-articular extension. Open and arthroscopic synovectomy, radiotherapy and pharmacologic agents have all been used to improve clinical symptoms and eradicate the abnormal synovial tissue. Reported treatment success in the literature is variable when judged by decreased knee pain and swelling along with prevention of recurrence. Arthroscopic excision alone has been associated with documented recurrence rates as high as 52% at 5 years after surgery.
Sohrab Keyhani, MD, and colleagues reported rather remarkable results in 21 patients treated with arthroscopic “complete synovectomy and septum removal,” including no complications or clinical recurrence at 5 years minimum follow-up. The surgeons employed a four-portal technique to remove all intra-articular synovium with a motorized shaver. Posterior compartment debridement was facilitated by connecting the posterolateral and posteromedial portals through the septum. No intra- or extra-articular radiation therapy was employed.
The authors are congratulated for their meticulous arthroscopic surgical skills, but the results are tempered by their patient selection, less sensitive outcome criteria and midterm follow-up. Any knee with soft tissue, bone or extra-articular extension was excluded. MRI screening was performed on only some their patients at 2 years after surgery, yet two cases of recurrence were identified. A higher failure rate would likely be detected by a 3T MRI at final follow-up and a longer time from surgery.
Nonetheless, this case series supports thorough arthroscopic removal of diffuse PVNS with a realistic goal of “subtotal,” but not “complete” synovectomy in order to improve symptoms and prevent or delay clinical recurrence. Surgeons should employ a six-portal technique, including anteromedial/anterolateral, posteromedial/posterolateral and superomedial/superolateral access, both 30° and 70° arthroscopes and a radiofrequency device to maximize the chance of long-term success. Treatment must be individualized according to patient characteristics, as well as disease location and extension. Combined arthroscopic and open posterior excision may be required in the setting of extra-articular disease proliferation. The role of adjuvant radiotherapy, kinase inhibitors and monoclonal antibody targeted therapy in recurrent cases deserves further study.
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Michael J. Stuart, MD
Division of sports medicine
Department of orthopedic surgery
Disclosures: Stuart reports he is a paid consultant for and receives royalties from Arthrex Inc.