Utilization of 3D-Printed Customized Uncemented Stem Prostheses for Revision of Aseptic Loosening in the Distal Femoral Cemented Prostheses: Case Series and Literature Review.

Objective: Aseptic loosening (AL) is a common mechanical complication following reconstruction of the distal femoral cemented prosthesis (DFCP), often resulting in severe bone loss, which complicates prosthesis revision. 3D-printed personalized implants represent an emerging solution for the reconstruction of complex bone defects. This study aimed to investigate the early therapeutic effects of using a 3D-printed, customized, uncemented stem prosthesis for revising aseptic AL in DFCP.

Methods: From June 2021 to December 2022, a retrospective review was conducted on six consecutive patients who underwent revision surgery due to AL of the DFCP with a 3D-printed customized uncemented stem prosthesis. The study included four male and two female patients, with an average age of 58 ± 11 (range: 46-75) years. All six patients had previously undergone limb salvage surgery using a cemented megaprosthesis after tumor resection. Preoperative imaging evaluation was performed for all patients, and the personalized design of the prostheses was achieved through 3D printing based on CT imaging data. Regular clinical and radiographic follow-up was conducted postoperatively, with the main outcome measures being oncological outcomes, prosthesis survival, osseointegration, complications, and lower limb function.

Results: All patients successfully underwent surgery and were followed up for a mean duration of 30.33 ± 6.15 (range: 24-38) months. All patients were alive at the last follow-up, with no tumor recurrence or distant metastasis. No complications such as infection, loosening, or fracture of the prosthesis occurred. Osseointegration was satisfactory, with a mean MSTS score of 26 (range: 20-28) points.

Conclusion: 3D-printed, customized, uncemented stem prosthesis exhibit immediate initial stability and reliable biocompatibility. Early clinical outcomes are satisfactory, making them an effective method for revision AL of DFCP.