Anterior Shoulder Instability With Bristow Procedure Versus Conjoined Tendon Transfer Alone in a Simple Soft-Tissue Model

Purpose We compared the Bristow procedure with a conjoined tendon transfer to investigate the role of the sling alone in restoring anterior translation in a simple soft-tissue instability model without bony defects. Methods Ten matched cadaveric shoulder pairs were randomly assigned to receive a Bristow procedure or a conjoined tendon transfer alone. Specimens were tested in a simple soft-tissue model with low load simulating anterior translation of the glenohumeral joint. The conditions (intact, cut, and repaired) and treatments (Bristow and conjoined tendon transfer alone) were compared for anteroposterior translation. Results Anterior translation increased from 3.4 ± 0.6 mm (mean ± SEM) to 12.0 ± 1.3 mm after the cut and decreased to 5.2 ± 0.7 mm with the Bristow procedure. Anterior translation increased from 2.8 ± 0.4 mm to 12.2 ± 1.9 mm after the cut and decreased to 4.9 ± 0.5 mm after conjoined tendon transfer alone. Although the repair increased the stability of the glenohumeral joint as reflected in significantly decreased anterior translation, anterior translation in the repaired joint was significantly greater than that in the intact condition for both procedures ( P < .05). There were no significant differences in anterior translation between the 2 treatments at any test stage. Conclusions There was no difference between the Bristow procedure and conjoined tendon transfer alone in restoring anteroposterior translation in a simple soft-tissue shoulder instability model with low load and no bony defect. Clinical Relevance Further investigation of the described conjoined tendon procedure should be done to evaluate the procedure with significant bony defects.