Bioprinting-based approaches for tendon reconstruction: A decade of advancement

Abstract

Tendon injuries remain difficult to manage because tendon tissue is relatively hypocellular and hypovascular and has limited regenerative capacity. Autograft and allograft reconstruction is constrained by donor-site morbidity, graft availability, variable biological incorporation, and incomplete restoration of native structure and mechanical function. Three-dimensional bioprinting, defined here as additive fabrication in which living cells are deposited within or alongside biomaterials, enables patient-specific constructs that aim to more closely approximate the hierarchical architecture of native tendon. Over the past decade, extrusion-, inkjet-, and laser-assisted platforms, together with collagen-, gelatin-, fibrin-, and extracellular matrix derived bioinks and synthetic polymer reinforcement, have improved construct properties. Tendon-specific preclinical studies, particularly rotator cuff tendon-to-bone models, report improved histological organisation and higher failure load or stiffness relative to repair-only controls, although the incremental contribution of printed cells has been inconsistent. Vascularisation, mechanical durability under cyclic loading, reproducible scale-up, and regulatory classification remain unresolved. Stimulus-responsive and self-healing bioinks, multi-material printing, vascular co-printing, and computational optimisation are promising but largely lack tendon-specific in vivo validation. This narrative review appraises a decade of progress, distinguishes cell-laden bioprinting from acellular additive manufacturing, and outlines the translational barriers preceding clinical adoption.

Keywords: Three-dimensional bioprinting; Tendon reconstruction; Tissue engineering; Bioink; Regenerative medicine; Tendon scaffold; Mesenchymal stem cells; Musculoskeletal reconstruction

Core Tip: Three-dimensional bioprinting offers a patient-specific alternative to autografts and allografts for tendon reconstruction, using layered deposition of bioinks, cells, and growth factors to recreate the hierarchical architecture of native tendon. This review summarises a decade of progress in bioink formulation, printing hardware, and biological integration, and outlines the remaining barriers to clinical translation, principally vascularisation of thick constructs, regulatory approval, cost, and the training of surgical teams to work with this technology.