Two Intramedullary and 1 Extramedullary Cortical Button, With or Without Interference Screw, Show Biomechanical Properties Superior to Native Tendon in Repair of the Distal Biceps Tendon: A Systematic Review and Network Meta-analysis of Biomechanical Performance

Abstract

The aim of this study was to use a systematic review and network meta-analysis (NMA) to compare the failure strength, maximum strength, stiffness, and displacement of available constructs for distal biceps repair. An NMA was conducted to determine the performance of 2 all-suture suture anchors (2x ASA), 2 intramedullary cortical buttons (2x IM CB), 2 suture anchors (2x SA), extramedullary cortical buttons (EM CB), extramedullary cortical button plus interference screw (EM CB+IFS), interference screw (IFS), single intramedullary cortical button (IM CB), single suture anchor (SA), trans-osseous suture (TOS), tension slide technique (TST), and tension slide technique plus suture tape (TST+ST). Analysis consisted of arm-based network meta-analysis under Bayesian random-effects model with Markov Chain Monte Carlo (MCMC) sampling. Biomechanical outcomes were summarized as treatment effects and their corresponding 95% confidence intervals (CI). Rank probabilities were calculated and used to generate each treatment's surface under the cumulative ranking (SUCRA) curve. Biomechanical properties were compared to native tendon. Displacement >10mm was defined as clinical failure. Twenty-one studies were included. For failure strength, no construct outperformed the native tendon but 2x SA, IFS, SA, and TOS demonstrated poorer failure strength. For the maximum load to failure, EM CB+IFS outperformed the native tendon. Compared to native tendon, EM CB+IFS, EM CB, and 2xIM CB were stiffer, while 2x SA and IFS were less stiff. No construct demonstrated >10 mm of displacement, but constructs with displacement above the mean (3.5 mm) included 2x ASA, 2xIM CB, and TOS. The fixation constructs that consistently demonstrated comparable or better biomechanical properties (failure strength, maximum strength, stiffness) to native tendon in distal biceps tendon repair were the extramedullary cortical button with or without interference screw and two intramedullary cortical buttons. No construct demonstrated displacement beyond standard definitions for clinical failure. This network meta-analysis of biomechanical studies suggest that extramedullary cortical button and two intramedullary cortical buttons may be the most stable construct for distal biceps repair fixation, with equivalent or better biomechanical properties compared to native tendon.