Page 82 - Reconstructive Techniques in Musculoskeletal Tumor Surgery

Chapter 4
Usually, full weight-bearing mobilization was started on the third postoperative day under supervision of a physical therapist. We used a rehabilitation protocol that is identical to that used in patients with revision hip arthroplasty. Starting from day three, partial weight-bearing with two crutches is allowed until six weeks postoperatively. Thereafter, patients start to mobilize with one crutch. We believe it is important to mobilize patients as soon as possible to lessen the likelihood of major complications such as thrombosis. In the rst days of mobilization, patients exercise for one to two hours and stay in bed during the remaining hours. Median postoperative hospital stay was 16 days (range, four days to 2.8 months). Routine follow-up included physical examination and radiographic and functional evaluation at one and six weeks; at three (conventional radiographs), six (conventional radiograph and CT), 12, and 24 months (conventional radiographs, CT and MRI); and yearly thereafter (conventional radiographs, MRI).
Medical records were evaluated to obtain characteristics of the patient, tumor, resection, and reconstruction. In consultation with the leading author (MPAB), one physician involved in the care of the patients in each center collected the data. Complications were classi ed according to Henderson et al20. Aseptic loosening and periprosthetic and prosthetic fractures were diagnosed on imaging or intraoperatively. Aseptic loosening was de ned as migration of the implant on conventional radiographs or CT or halo formation on CT in the absence of infection. Infection was de ned as any deep (periprosthetic) infectious process diagnosed by physical examination, imaging, laboratory tests (C-reactive protein, erythrocyte sedimentation rate, leukocyte count), and microbiologic cultures. The occurrence of local recurrences was determined on imaging (usually MRI) and on histopathology in case surgery was performed. Failure was de ned as removal or revision of (part of ) the implant for any reason.
Statistical Analysis
A competing risks model was used to estimate the cumulative incidence of implant failure for mechanical failure and infection with patient mortality as a competing event21, 22. A Cox regression model was used to study the e ect of prognostic factors on survival. Categorical variables were compared between groups with chi-square tests and numerical variables with Mann-Whitney U tests. Outcomes are expressed in hazard ratios (HRs), 95% CIs, and p-values. Functional outcome was assessed with the 1993 version of the MSTS questionnaires23 at last
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