Page 194 - Reconstructive Techniques in Musculoskeletal Tumor Surgery

Chapter 9
some cases of failure were managed while the same implant was in place (for example the cases of loosening that were managed with cemented re- xation of the implant or failure of the locking mechanism, which was managed with revision of the polyethylene lock). In all, 55 patients (55 of 101 [55%]) required a total of 141 further surgical procedures: 78 (78 of 141 [55%]) for infection and 42 (42 of 141 [30%]) for mechanical reasons. At review, 90 patients (90 of 101 [89%]) had a MUTARS in situ. Above-knee amputations were undertaken in seven patients (seven of 101 [7%]; ve as a result of a local recurrence, two resulting from infection), rotationplasty in two (two of 101 [2%]; one as a result of local recurrence, one resulting from infection), total femoral replacement in one (one of 101 [1%], as a result of loosening and poor remnant host bone), and knee disarticulation in one (as a result of a periprosthetic fracture).
Discussion
Modular endoprostheses are frequently used to reconstruct skeletal and knee defects created by resecting a bone neoplasm from the distal femur or proximal tibia. However, they are associated with substantial complication rates on both the short and long term, most notably infection and aseptic loosening5, 6, 16. We sought to evaluate the long-term results of knee arthroplasty with MUTARS modular endoprostheses in the treatment of primary tumors, emphasizing on mechanical complications.
Our study has a number of limitations. Preferably, one would report on proximal tibial and distal femoral replacements separately because they may di er in the types of complications by site. However, we were hampered by a limited number of patients and we therefore chose to report on knee arthroplasty as one group. We grouped patients who had a previous reconstruction together with those reconstructions done for a primary resection and these groups are disparate, which might have in uenced our overall risk of loosening. However, we feel that the results as now presented best describe our clinical experiences with this implant system during the period under study. Moreover, as a result of the long retrospective period of our study, we were unable to obtain functional outcome scores and quality of life scores. We had no comparison groups so we are unable to determine if this endoprosthesis o ers advantages or disadvantages compared with other prostheses or types of reconstruction.
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