Limb-Salvage Reconstruction of the Proximal Humerus Using Patient-Specific 3D-Printed PEEK Implants: A Midterm...

Area of Science:

• Orthopedic Oncology
• Biomaterials Engineering
• 3D Printing Technology

Background:

• Proximal humerus reconstruction after tumor resection faces challenges with traditional methods like allografts and metal implants due to limitations such as availability, cost, and biomechanical mismatch.
• Polyether ether ketone (PEEK), a polymer with properties closer to bone and radiolucency, presents a promising alternative for orthopedic reconstruction.
• This study introduces the novel application of patient-specific 3D-printed PEEK implants for proximal humerus reconstruction.

Purpose of the Study:

• To evaluate the feasibility, safety, and outcomes of using patient-specific 3D-printed PEEK implants for proximal humerus reconstruction following wide tumor resection.
• To assess implant survival, oncologic control, and functional restoration in patients treated with these novel implants.

Main Methods:

• A retrospective cohort study involving seven patients who underwent proximal humerus tumor resection and reconstruction with patient-specific 3D-printed PEEK implants.
• Implant design utilized preoperative CT scans, contralateral mirroring, and CAD; fabrication involved fused deposition modeling (FDM) with medical-grade PEEK and post-processing annealing.
• Outcomes assessed included implant survival, oncologic control, shoulder range of motion, and Musculoskeletal Tumor Society (MSTS) scores, with a mean follow-up of 56.3 months.

Main Results:

• All patient-specific PEEK implants were successfully manufactured and implanted with good geometric accuracy.
• Mechanical implant survival was 85.7%, with one fracture; no infections, dislocations, or loosening occurred. Limb salvage rate was 100%.
• The mean MSTS score was 23.0, and shoulder motion was comparable to conventional reconstructions; two patients had local recurrence without metastasis.

Conclusions:

• Patient-specific 3D-printed PEEK implants are a feasible and oncologically safe option for proximal humerus reconstruction after tumor resection.
• These implants offer acceptable midterm survival and functional outcomes, with biomechanical and imaging advantages over metallic alternatives.
• Further research focusing on design optimization and prospective studies is recommended to improve mechanical durability and functional restoration.