We describe a new method of reconstruction of the extensor apparatus after extensive resection of malignant tumours around the knee joint with a polyester ligament. Twenty- two patients after a mean follow up of eighteen months (six to thirty-six months) were treated. Six patients had excellent knee function with a lag of extension less than five degrees, four of less than twenty, three had less than forty degrees and six patients could not lift their limb extended against gravity, although no patient required any kind of walking aid. The mean Enneking Score was 81.5 the mean TESS Score was eighty-three. Limb salvage surgery in primary malignant bone tumours is widely accepted as the surgical treatment of choice around the knee joint. Extraarticular resection for oncological radicality usually results in additional resection of at least part of the extensor mechanism Since January 2000 we used a Polyester Band (LARS®) for either augmentation of a transposed muscle or as a complete soft tissue bridging after tumour resection in twenty-two patients (fourteen men, eight women) with a mean age of thirty-two (8–75). The HMRS tumour endoprosthesis was used for the reconstruction of the knee joint. The location of the tumour was in the distal femur in ten cases and the proximal tibia in eleven. One synovial sarcoma arose at the lateral meniscus. The mean follow up was eighteen months (6–36) after implantation of the Lars® ligament. Patient’s functional outcome and satisfaction was eighty-three (65–92) at the TESS Score and 81,5 (43–92) at the Enneking Score, respectively. Six patients had excellent knee function with an extension deficit of less than five degrees. In four cases the extension deficit was less than twenty, in three cases it was less than forty. In six patients the active extension lag was more than forty degrees. However, their remaining quadriceps strength was sufficient for stabilisation of the knee joint during gait without any aids. At last follow up all implants were in situ without any signs of loosening. No patient had to be amputated because of septic complication.
