Page 188 - Reconstructive Techniques in Musculoskeletal Tumor Surgery

Chapter 9
In cases in which an extensor mechanism reconstruction had to be performed, we ran non-absorbable sutures through the designated holes in the tibial component to x an attachment tube (implantcast) to the implant; the extensor mechanism was later attached to the tube, again using non-absorbable sutures. After assemblage of the prosthesis, a trial reduction was performed. A nal check was performed to assess knee motion and soft tissue tension and subsequently, the implant was locked.
All patients received prophylactic intravenous cephalosporins before surgery; these were continued for one to ve days. Drains were removed after a maximum of 48 hours. Based on pain, patients were mobilized under supervision of a physical therapist, usually on the rst postoperative day. Antithrombotic prophylaxis was given until 6 weeks postoperatively.
Patients were followed during outpatient visits at two and six weeks after discharge, after three and six months, and every six months thereafter. Radiographic follow-up consisted of conventional radiographs and additional imaging (CT/ MRI) if complications or recurrence were suspected.
Complications and failures were recorded and classi ed according to Henderson et al15, 20. Aseptic loosening was de ned as migration of the prosthesis on imaging (periprosthetic lucency on conventional radiographs or CT scan or halo formation on CT) in the absence of infection. We however chose to report on the clinical rather than radiological loosening, i.e., those that required revision, partly because it can be hard to determine which cases are at risk for future failure/ loosening, and it is therefore di cult to reliably comment on the occurrence and signi cance of these signs. Radiographic signs alone were not observed as a reason for implant failure. Rates of aseptic loosening were compared between primary and revision reconstructions (arthroscopy, curettage, and conventional TKA were not considered as previous reconstructions). Periprosthetic and prosthetic fractures were diagnosed on imaging or intraoperatively. Infection was de ned as any deep (periprosthetic) infectious process diagnosed through physical examination, imaging, laboratory tests (including C-reactive protein, erythrocyte sedimentation rate, and synovial uid leukocyte count) and microbiologic cultures.
Statistical Analysis
All data were complete. To estimate the cumulative incidence of revision for di erent types of failure, a competing risks model was used with patient mortality as a competing event21, 22. Failures were de ned as removal of part of or all of the
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