Mid-Term Outcome After Curettage with Polymethylmethacrylate for Giant Cell Tumor Around the Knee: Higher Risk of Radiographic Osteoarthritis? Lizz van der Heijden, MSc, Michiel A.J. van de Sande, MD, PhD, Adriaan C. Heineken, Marta Fiocco, PhD, Rob G.H.H. Nelissen, MD, PhD, and P.D. Sander Dijkstra, MD, PhD Investigation performed at Leiden University Medical Center, Leiden, the Netherlands Background: It has been suggested that, when a patient has a giant cell tumor, subchondral bone involvement close to articular cartilage and a hyperthermic reaction from polymethylmethacrylate (PMMA) are risk factors for the development of osteoarthritis. We determined the prevalence, risk factors, and clinical relevance of osteo- arthritis on radiographs after curettage and application of PMMA for the treatment of giant cell tumors around the knee. Methods: This retrospective single-center study included fifty-three patients with giant cell tumor around the knee treated with curettage and PMMA between 1987 and 2007. The median age at the time of follow-up was forty-two years (range, twenty-three to seventy years). There were twenty-nine women. Radiographic evidence of osteoarthritis was defined, preoperatively and postoperatively, as Kellgren and Lawrence grade 3 or 4 (KL3-4). We studied the influence of age, sex, tumor-cartilage distance, subchondral bone involvement (£3 mm of residual subchondral bone), subchondral bone-grafting, intra-articular fracture, multiple curettage procedures, and complications on progression to KL3-4. Func- tional outcomes and quality of life were assessed with the Short Form-36 (SF-36), Musculoskeletal Tumor Society (MSTS) score, and Knee injury and Osteoarthritis Outcome Score (KOOS). Results: After a median duration of follow-up of eighty-six months (range, sixty to 285 months), six patients (11%) had progression to KL3, two (4%) had progression to KL4, and one had preexistent KL4. No patient underwent total knee replacement. The hazard ratio for KL3-4 was 9.0 (95% confidence interval [CI] = 2.0 to 41; p = 0.004) when >70% of the subchondral bone was affected and 4.2 (95% CI = 0.84 to 21; p = 0.081) when the tumor- cartilage distance was £3 mm. Age, sex, subchondral bone-grafting, intra-articular fracture, multiple curettage procedures, and complications did not affect progression to KL3-4. Patients with KL3-4 reported lower scores on the KOOS symptom subscale (58 versus 82; p = 0.01), but their scores on the other KOOS subscales, the MSTS score (21 versus 24), and the SF-36 (76 versus 81) were similar to those for the patients with KL0, 1, or 2 (KL0-2). Conclusions: Seventeen percent of patients with giant cell tumor around the knee had radiographic findings of osteo- arthritis after treatment with curettage and PMMA. A large amount of subchondral bone involvement close to articular cartilage increased the risk for osteoarthritis. The function and quality of life of the patients with KL3-4 were comparable with those for the patients with KL0-2, suggesting that radiographic findings of osteoarthritis at the time of intermediate continued Disclosure: One or more of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of an aspect of this work. In addition, one or more of the authors, or his or her institution, has had a financial relationship, in the thirty-six months prior to submission of this work, with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. No author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article. e159(1) COPYRIGHT Ó 2013 BY THE J OURNAL OF BONE AND J OINT SURGERY,I NCORPORATED J Bone Joint Surg Am. 2013;95:e159(1-10) d http://dx.doi.org/10.2106/JBJS.M.00066 Downloaded From: http://jbjs.org/ by a Leids Unnivers. Medisch Centrum User on 11/07/2013