AimsPatient-specific Ti-6Al-4V lattice implants present a new era for reconstruction of weightbearing segmental defects; however, robust clinical data from larger cohorts with longer follow-up remain limited. Building on our previous study that detailed the engineering, design, and surgical workflow of these implants, this study focuses on clinical outcomes. Specifically, we aimed to: 1) characterize surgical complications and limb-salvage rates; 2) report resection margins and oncological status at the latest follow-up; and 3) describe functional outcomes.MethodsThis retrospective single-centre study includes 29 patients treated between January 2016 and December 2024 with long-bone tumour resection (n = 28) or post-traumatic nonunion (n = 1) of the femur or tibia. Resections were guided by intraoperative 3D-printed osteotomy patient-specific instruments followed by reconstruction with customized Ti-6Al-4V lattice implants. Minimum follow-up was 12 months. Surgical complications, reoperations, resection margins, metastasis, and local recurrence were recorded. Musculoskeletal Tumor Society (MSTS) scores were obtained at latest follow-up.ResultsThe mean age was 26.2 years (SD 18.0); anatomical sites were tibia (15/29, 52%) and femur (14/29, 48%). Early complications occurred in 3/29 (10.3%; one haematoma, two deep infections); late complications occurred in 4/29 (13.7%; one deep infection requiring staged revision with implant removal and fibular grafting, one mechanical failure revised to a megaprosthesis at four months, one subtalar fusion for symptomatic nonunion, and one component loosening and subluxation). Limb salvage was achieved in 27/29 patients (93.1%). At latest follow-up, 23 patients were with no evidence of disease, two alive with evidence of disease, and three dead of disease; metastasis occurred in seven patients and local recurrence in four patients. The median MSTS at latest follow-up was 80% (IQR 60% to 87%).ConclusionIn this heterogeneous cohort, patient-specific Ti-6Al-4V lattice implants achieved reliable reconstruction with acceptable complication rates, high limb salvage, and oncological control, with high functional outcomes, supporting this approach as a practical and effective solution for critical-sized, weightbearing defects reconstruction.Cite this article: Bone Jt Open 2026;7(4):507–518.