Precision Reconstruction of Complex Orthopedic Defects Using Patient-Specific 3D-Printed Implants: A Clinical Evaluation of Anatomical Restoration, Implant Integration, and Mid-Term Outcomes

Abstract

Reconstruction of complex orthopedic defects resulting from tumor resection, revision arthroplasty, severe trauma, and congenital deformities remains one of the greatest challenges in orthopedic surgery because conventional reconstructive approaches, including standard off-the-shelf implants, structural allografts, and modular megaprostheses, are often constrained by anatomical mismatch, insufficient fixation, and limited biological integration. Advances in additive manufacturing have enabled the production of patient-specific titanium implants with complex geometries and porous architectures tailored to individual anatomical defects, offering the potential to improve implant stability, osseointegration, and functional recovery. However, prospective clinical evidence supporting their effectiveness remains limited. This prospective cohort study evaluated the clinical performance of patient-specific three-dimensional (3D)-printed Ti-6Al-4V implants for the reconstruction of complex orthopedic defects, with particular emphasis on anatomical restoration, implant–bone integration, functional outcomes, and mid-term implant survivorship. Seventy-four patients (42 men and 32 women; mean age, 52.4 ± 15.6 years) underwent reconstruction between January 2021 and June 2024 for tumor-related bone defects (n = 28), revision arthroplasty with severe bone loss (n = 22), post-traumatic segmental defects (n = 16), or congenital deformity reconstruction (n = 8). Patient-specific implants were designed from computed tomography-derived three-dimensional anatomical models using computer-aided design with topology optimization and manufactured by electron beam melting to produce trabecular-inspired porous structures with pore sizes of 300–800 μm and porosity ranging from 65% to 80%. Primary outcomes included postoperative anatomical restoration accuracy determined by computed tomography-based three-dimensional deviation analysis and implant integration evaluated using radiographic bone ingrowth scores. Secondary outcomes comprised functional recovery assessed by the Musculoskeletal Tumor Society (MSTS) score, Harris Hip Score, Knee Society Score, Visual Analog Scale (VAS) pain score, Short Form-36 (SF-36), postoperative complications, and implant survival. After a mean follow-up of 38.4 ± 10.2 months, anatomical restoration was achieved with a mean three-dimensional deviation of 1.8 ± 0.7 mm (95% CI, 1.6–2.0 mm) between the planned and achieved implant positions. Bone–implant integration was observed in 68 patients (91.9%) within 12 months, with complete radiographic osseointegration achieved in 61 patients (82.4%). Functional outcomes improved significantly, with the mean MSTS score increasing from 38.2 ± 11.4 to 78.6 ± 9.8 (p < 0.001), the Harris Hip Score from 41.6 ± 14.2 to 86.4 ± 8.6 (p < 0.001), and the Knee Society Score from 39.8 ± 13.6 to 82.2 ± 10.4 (p < 0.001), while VAS pain scores decreased from 6.8 ± 1.6 to 1.9 ± 1.2 (p < 0.001). The overall complication rate was 20.3%, including deep infection (5.4%), aseptic loosening (4.1%), implant fracture (2.7%), and screw breakage (4.1%), with revision surgery required in eight patients (10.8%). Kaplan–Meier analysis demonstrated a three-year implant survival rate of 89.2% (95% CI, 82.1–94.5%). These findings demonstrate that patient-specific 3D-printed titanium implants provide an effective personalized reconstructive strategy for managing complex orthopedic defects by enabling highly accurate anatomical restoration, reliable osseointegration, substantial improvements in functional recovery, and encouraging mid-term implant survivorship. Collectively, the results support the continued clinical translation of patient-specific additive manufacturing in orthopedic reconstruction, while emphasizing the need for larger multicenter studies with longer follow-up to establish long-term durability, cost-effectiveness, and broader clinical applicability.