Secondary Osteoarthritis After Curettage and Calcium Phosphate Cementing for Giant-Cell Tumor of Bone Around the Knee Joint Long-Term Follow-up

Abstract

Background: Giant-cell tumor of bone (GCTB) is a locally aggressive intermediate bone tumor with a rarely metastasizing disposition. Standard surgical treatment consists of curettage, adjuvant treatment, and augmentation with allograft, autograft, or synthetics. Polymethylmethacrylate (PMMA) has been widely used for augmentation of the bone defect; however, the hyperthermic polymerization of PMMA may cause damage to articular cartilage, and the stiffness of the material may decrease the ability of the joint to absorb shock. These properties were reported to result in secondary osteoarthritis. Calcium phosphate cement has a low degree of thermal reaction and a strength that is similar to cortical bone. The aim of the present study was to investigate the incidence of secondary osteoarthritis around the knee joint following augmentation with calcium phosphate cement. Methods: We retrospectively evaluated 19 patients with primary GCTB from 2003 to 2012. Curettage, high-speed burring, phenolization, and filling with calcium phosphate cement were performed in all patients. Radiographic evidence of osteoarthritis progression was evaluated with use of the Kellgren-Lawrence grade; the postoperative grade was compared with both the preoperative grade and the grade of the nonoperative contralateral knee at the time of the latest follow-up. The Musculoskeletal Tumor Society score and oncological outcomes at the time of the latest follow-up were evaluated. Results: At a median follow-up period of 131 months, osteoarthritic progression was observed in 5 patients (26%), of which 2 were classified as Kellgren-Lawrence grade 3 and 1 was classified as Kellgren-Lawrence grade 4. The patient with grade-4 osteoarthritis underwent total knee arthroplasty, and 1 of the patients with grade-3 osteoarthritis underwent open-wedge high tibial osteotomy. The 10-year survival rate of joint cartilage with a Kellgren-Lawrence grade of <3 was 83%. The average Musculoskeletal Tumor Society score was 29 points. GCTB recurred in 2 patients, and 1 of these patients developed pulmonary metastasis. Conclusions: The incidence of secondary osteoarthritis was low, despite the long follow-up period. Prospective investigation comparing PMMA and calcium phosphate cement is warranted to determine the relative rate of secondary osteoarthritis and the outcomes associated with the 2 different types of augmentation. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.