Revision of the Kotz type of tumour endoprosthesis for the lower limb

Abstract

I n 251 patients over a period of 15 years an uncemented Kotz modular femoral and tibial reconstruction mega prosthesis was implanted after resection of a malignant tumour of the lower limb. Twenty-one patients (8.4%) underwent revision for aseptic loosening, again using an uncemented prosthesis, and five of these required a further revision procedure. The median follow-up time from the first revision was 60 months (11 to 168) and after a second revision, 33 months (2 to 50). The probability of a patient avoiding aseptic loosening for ten years was 96% for a proximal femoral, 76% for a distal femoral and 85% for a proximal tibial implant.At the time of follow-up all radiographs were assessed according to the International Symposium of Limb Salvage criteria. The first radiological signs of aseptic loosening were always seen at the most proximal or distal part of the anchorage stem at a mean of 12 months (4 to 23) after the first implantation. Using the Musculoskeletal Tumor Society score for evaluation, the clinical results showed a mean of 88% of normal function.

Does Competing Risk Analysis Give Useful Information About Endoprosthetic Survival in Extremity Osteosarcoma?

“…These included 26 Kotz Modular Femur Tibia Reconstruction System (KMFTR 1 ; Stryker-Howmedica Inc, Mahwah, NJ, USA), 188 Howmedica Modular Resection System (HMRS; Howmedica GmBH, Kiel, Germany), and 33 Global Modular Replacement System (GMRS, Stryker GmbH & Co KG, Duisburg, Germany). The major differences are represented by continuously adapted stem designs and the modular rotating hinge mechanism of the more recent generations that replaced the fixed hinge mechanism of the older devices for replacement of the knee [6,11,14,15,18]. In all but 11 implants, cementless fixation was used.…”

“…The frequency of limb salvage surgery for patients with primary bone malignancies using modular endoprostheses has steadily increased during the last decades and during this time, endoprosthetic survival has improved because of advances in design, manufacturing, and surgical techniques [15]. However, complication rates are still high as a result of a variety of factors including factors such as the large dead space in the tumor bed surrounding the prosthesis, wide soft tissue exposure, fixation issues of the implants, and immune suppression.…”

“…Because malignant bone tumors are rare, reports about survivorship and complications of tumor endoprostheses generally are limited to small cohorts with relatively short followup [6,7,10,14,15] and commonly these investigations apply Kaplan-Meier estimations and Cox regression models to describe endoprosthetic survival. These analyses deal principally with one event as an endpoint, for example revision surgery, independent of its cause [20].…”

Total Femur Replacement After Tumor Resection: Limb Salvage Usually Achieved But Complications and Failures are Common

“…Improvements in implant design and manufacturing and advances in surgical techniques [21] and adjuvant treatments for malignancies have resulted in limb-salvage surgery after tumor resection becoming a standard approach. Modular endoprosthetic reconstruction of single joints has become a well-established treatment option, especially for patients needing hip or knee reconstruction.…”

“…Some of the studies reported results for total femur replacements together with partial femur reconstructions, which makes it difficult to draw conclusions for total femur replacement-specific complications [1,21]. Most of the studies emphasized oncologic and functional outcomes of the patients; only a few specifically addressed the modes by which total femur replacement failed.…”