Joint-Sparing Resection of Juxta-Articular Primary Tumors of the Knee Using Titanium Alloy 3D-Printed Cutting Guides and Allograft Reconstruction.

Joint-sparing resection of juxta-articular knee tumors is challenging. With the development of 3D printing technology, custom-made cutting guides were introduced with the aim to improve the accuracy of tumor resection margins and to shape the allograft for adequate matching in biological reconstruction. Between December 2017 and July 2023, 13 patients underwent joint-sparing juxta-articular resection of the knee for a primary bone tumor at our institution. Resection was performed using a custom-made 3D-printed titanium alloy cutting guide and reconstruction was performed using a custom-shaped allograft. The mean follow up was 50 months (min 14-max 81). The study of cutting accuracy was performed by digital examination of CT images of the resection specimen in eight patients. The average cutting error was 2.3 mm. Surgical margins were wide in all patients. Four patients developed postoperative complications that led to the removal of the allograft in one case. The average functional result according to the Musculoskeletal Tumor Society Score was 26 (min 14-max 30), and according to the Oxford Knee Score it was 44 (min 22-max 48). Custom-made titanium cutting guides resulted effective in improving the accuracy of joint-sparing juxta-articular resection of the knee and allograft matching.