What Are the MSTS Scores and Complications Associated With the Use of Three-dimensional Printed, Custom-made Prostheses in Patients Who Had Resection of Tumors of the Hand and Foot?
Authors: Chandhanayingyong Chandhanarat , Thanapipatsiri Pannin , Pairojboriboon Sutipat , Luenam Suriya , Hongsaprabhas Chindanai , Charoenlap Chris , Wattanapaiboon Komkrich , Asavamongkolkul Apichat , Tharmviboonsri Theerawoot , Phimolsarnti Rapin 
Published: June 2023

Abstract

Background
There are a few good options for restoring bone defects in the hand and foot. 3D-printed implants have been used in the pelvis and elsewhere, but to our knowledge, they have not been evaluated in the hand and foot. The functional outcome, complications, and longevity of 3D-printed prostheses in small bones are not well known.

Questions/purposes
(1) What are the functional outcomes of patients with hand or foot tumors who were treated with tumor resection and reconstruction with a 3D-printed custom prosthesis? (2) What complications are associated with using these prostheses? (3) What is the 5-year Kaplan-Meier cumulative incidence of implant breakage and reoperation?

Methods
Between January 2017 and October 2020, we treated 276 patients who had tumors of the hands or feet. Of those, we considered as potentially eligible patients who might have extensive loss in their joint that could not be fixed with a bone graft, cement, or any prostheses available on the market. Based on this, 93 patients were eligible; a further 77 were excluded because they received nonoperative treatment such as chemoradiation, resection without reconstruction, reconstruction using other materials, or ray amputation; another three were lost before the minimum study follow-up of 2 years and two had incomplete datasets, leaving 11 for analysis in this retrospective study. There were seven women and four men. The median age was 29 years (range 11 to 71 years). There were five hand tumors and six tumors of the feet. Tumor types were giant cell tumor of bone (five), chondroblastoma (two), osteosarcoma (two), neuroendocrine tumor (one), and squamous cell carcinoma (one). Margin status after resection was ≥ 1 mm. All patients were followed for a minimum of 24 months. The median follow-up time was 47 months (range 25 to 67 months). Clinical data; function according to the Musculoskeletal Tumor Society, DASH, and American Orthopedic Foot and Ankle Society scores; complications; and survivorship of implants were recorded during follow-up in the clinic, or patients with complete charts and recorded data were interviewed on the telephone by our research associates, orthopaedic oncology fellows, or the surgeons who performed the surgery. The cumulative incidence of implant breakage and reoperation was assessed using a Kaplan-Meier analysis.

Results
The median Musculoskeletal Tumor Society score was 28 of 30 (range 21 to 30). Seven of 11 patients experienced postoperative complications, primarily including hyperextension deformity and joint stiffness (three patients), joint subluxation (two), aseptic loosening (one), broken stem (one), and broken plate (one), but no infection or local recurrence occurred. Subluxations of the metacarpophalangeal and proximal interphalangeal joints in two patients’ hands were caused by the design of the prosthesis without a joint or stem. These prostheses were revised to a second-generation prosthesis with joint and stem, leading to improved dexterity. The cumulative incidence of implant breakage and reoperation in the Kaplan-Meier analysis was 35% (95% CI 6% to 69%) and 29% (95% CI 3% to 66%) at 5 years, respectively.

Conclusion
These preliminary findings suggest that 3D implants may be an option for reconstruction after resections that leave large bone and joint defects in the hand and foot. Although the functional results generally appeared to be good to excellent, complications and reoperations were frequent; thus, we believe this approach could be considered when patients have few or no alternatives other than amputation. Future studies will need to compare this approach to bone grafting or bone cementation.

Level of Evidence
Level IV, therapeutic study.