Page 189 - Reconstructive Techniques in Musculoskeletal Tumor Surgery

implant, major revision (exchange of the femoral component, tibial component, or the locking mechanism), or cemented re- xation as the endpoint. Failure did not include isolated revision of the bushing. The in uence of potential risk factors on the cumulative incidence of revision was determined with Cox regression analyses. SPSS 21.0 (IBM Corp, Armonk, NY, USA) was used for statistical analysis (level of signi cance, p < 0.050). All analyses for the competing risk models have been performed with the mstate library23 in the R software package24.
Mean age at surgery was 36 years (range, 13 – 82 years). Predominant diagnoses were osteosarcoma (n = 56 [55%]), leiomyosarcoma of bone (n = 10 [10%]), chondrosarcoma (n = 9 [9%]), giant cell tumor of bone (n = 8 [8%]), and pleomorphic undi erentiated sarcoma (n = 7 [7%]). Sixty-four patients (64 of 101 [63%]) were treated with chemotherapy (according to appropriate protocols) around the period of MUTARS implantation and four (four of 101 [4%]) underwent radiotherapy.
Eighty-nine reconstructions (81%) were distal femoral replacements and 21
(19%) were proximal tibial replacements. Eleven distal femoral replacements (11
of 89 [12%]) had a cemented femoral stem. Of 78 uncemented distal femoral replacements (78 of 89 [88%]), 42 were HA-coated (42 of 78 [54%]). All proximal
tibial replacements had an uncemented tibial stem, 12 of which were HA-coated
(12 of 19 [57%]) ( gures 1A–B); one (one of 21 [5%]) had a cemented femoral
stem. Patellar components were used in 37 distal femoral replacements (37 of 89
[42%]) and in three proximal tibial replacements (three of 21 [14%]). Median total
resection length was 16 cm (range, 12 – 30 cm) for distal femoral replacements and
14 cm (range, 12 – 26 cm) for proximal tibial replacements. Attachment tubes were 9 used in 14 proximal tibial replacements (14 of 21 [67%]) and in two distal femoral replacements (two of 89 [2%]). An extensor reconstruction was performed in 11
proximal tibial replacements (11 of 21 [58%]) and six distal femoral replacements
(six of 89 [7%]). Rotation of a gastrocnemius muscle ap was performed in four
proximal tibial replacements (four of 21 [19%], in one case combined with a split
skin graft). Allogeneic fascia lata were used in six distal femoral replacements (six of
89 [7%]) and in two proximal tibial replacements (two of 21 [10%]). Three implants
(three of 110 [3%]) were silver-coated.
During tumor resection, clear surgical margins were obtained in 95 patients (95 of 101 [94%]). Two patients (two of 101 [2%]) with giant cell tumors had intentional intralesional surgery. Four patients (four of 101 [5%]) had contaminated margins.
MUTARS knee replacement
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