Aims. We have evaluated the survivorship, outcomes, and failures of an interlocking, reconstruction-mode stem-sideplate implant used to preserve the native hip joint and achieve proximal fixation when there is little residual femur during large endoprosthetic reconstruction of the distal femur. Methods. A total of 14 patients underwent primary or revision reconstruction of a large femoral defect with a short remaining proximal femur using an interlocking, reconstruction-mode stem-sideplate for fixation after oncological distal femoral and diaphyseal resections. The implant was attached to a standard endoprosthetic reconstruction system. The implant was attached to a standard endoprosthetic reconstruction system. None of the femoral revisions were amenable to standard cemented or uncemented stem fixation. Patient and disease characteristics, surgical history, final ambulatory status. ,. and Musculoskeletal Tumor Society (MSTS) score were recorded. The percentage of proximal femur remaining was calculated from follow-up radiographs. Results. All 14 at-risk native hip joints were preserved at a mean final follow-up of 6.0 years (SD 3.7), despite a short residual femur, often after proximal osteotomies through the lesser trochanter. Overall, 13 of 14 stems had long-term successful fixation. Eight patients required no reoperation. Three patients required reoperation due to implant-related issues, and three patients required reoperation for wound healing problems or infection. There were no dislocations or fractures. At final follow-up the mean MSTS score was 24.9 (SD 4.1). Nine patients required no ambulation aids, and only one had a Trendelenburg gait. Conclusion. This interlocking, reconstruction-mode stem-sideplate reliably preserves native hip joint anatomy and function after large femoral resection with a short remaining proximal femur, both in the primary and revision setting. This is particularly important for preventing or delaying total femoral arthroplasty in young patients after oncological reconstruction. Hip abductor strength and function could be maintained by this method, and the risk of dislocation eliminated. The success of this technique in this modest series should be verified in a larger collaborative study and will be of interest to revision surgeons and oncologists. Cite this article: Bone Joint J 2021;103-B(2):398–404

Aims

The use of a noninvasive growing endoprosthesis in the management of primary bone tumours in children is well established. However, the efficacy of such a prosthesis in those requiring a revision procedure has yet to be established. The aim of this series was to present our results using extendable prostheses for the revision of previous endoprostheses.

Endoprosthetic reconstruction following resection of 31 tumours of the proximal femur in 30 patients was performed using a Wagner SL femoral revision stem. The mean follow-up was 25.6 months (0.6 to 130.0). Of the 28 patients with a metastasis, 27 died within a mean follow-up period of 18.1 months (0.6 to 56.3) after the operation, and the remaining patient was excluded from the study 44.4 months post-operatively when the stem was removed. The two patients with primary bone tumours were still alive at the latest follow-up of 81.0 and 130.0 months, respectively. One stem only was removed for suspected low-grade infection 44.4 months post-operatively. The worst-case survival rate with removal of the stem for any cause and/or loss to follow-up was 80.0% (95% confidence interval 44.9 to 100) at 130.0 months. The mean Karnofsky index increased from 44.2% (20% to 70%) pre-operatively to 59.7% (0% to 100%) post-operatively, and the mean Merle d’Aubigné score improved from 4.5 (0 to 15) to 12.0 (0 to 18). The mean post-operative Musculoskeletal Tumour Society score was 62.4% (3.3% to 100%). The Wagner SL femoral revision stem offers an alternative to special tumour prostheses for the treatment of primary and secondary tumours of the proximal femur. The mid-term results are very promising, but long-term experience is necessary