Friction and interfacial mechanics of surgical suturing: needle–tissue penetration, suture drag and friction-control strategies

Surgical suturing involves a sequence of tribological contacts that begins with needle penetration, continues through suture pull-through, and culminates in knot tightening and locking. Uncontrolled friction at these interfaces can cause tissue trauma, coating delamination, or knot slippage. This narrative review synthesises the biomechanics and tribology of the needle–tissue, suture–tissue, and suture–suture interfaces. PubMed, Scopus and Web of Science were searched for studies published from January 2000 to July 2026, and studies were selected for mechanical relevance and synthesised by tribological interface. Needle insertion force is a combined response of tissue deformation, cutting and shaft friction, with attention to needle geometry, trajectory, velocity, tissue properties and force sensing. Suture drag is examined in relation to material, diameter, surface roughness, monofilament or multifilament construction, hydration, loading and pulling speed. Surface-engineering approaches, including lubricants, silicone and polymeric treatments, antimicrobial coatings, dopamine-, chitosan- and graphene-based modifications, and tissue-integrating sutures, are evaluated for friction reduction, durability, handling and knot performance. The review also discusses the transition from low resistance during passage to sufficient suture–suture friction after tightening, together with experimental apparatus, biological tissue models, finite-element methods and robotic force feedback. Evidence shows that friction is stage-dependent and should be controlled rather than uniformly minimised. Future progress will depend on standardised wet-tissue testing, clearer separation of force components, repeated-passage evaluation of coatings, tissue-specific needle–suture selection, and stronger links between mechanical measurements, tissue response and adaptive robotic control.