A novel augmentation technique for the repair of full thickness gluteal tendon tears: a biomechanical analysis in an ovine model.

Abstract

Background: Gluteus medius tendon tears lead to considerable functional limitations and a high level of suffering in affected patients. In cases where the symptoms are severe, surgical intervention is indicated. A range of techniques are used to repair the tendon, with the primary aim being to achieve the highest possible primary stability in order to minimise the risk of re-rupture. This biomechanical study compares two different refixation techniques in terms of their stability in an ovine model.

Material and methods: The gluteal tendons of sheep hips (n = 17) were meticulously prepared and detached from the femoral insertion. To reattach these tendons at their original anatomical footprint, either the sole double-row transosseous-equivalent technique (DR) or the DR supplemented by a proximal suture insertion (augmentation) of the tendon (DR +) was used. Pull-out tests were performed until failure using a uniaxial material testing machine, with a tensile force applied along the physiological tensile direction of the hip abductors. The data obtained (force at failure, linear stiffness) were compared between the groups using the Mann-Whitney U test.

Results: The augmentation of the proximal tendon portion resulted in a substantial increase in force at failure, exceeding 450% (698 ± 80.3 N DR + compared with 155.9 ± 53.9 N DR technique). In addition, augmented tendons exhibited a notable enhancement in stiffness, with an average increase of 31.3 ± 15 N/mm in DR + compared with 12.4 ± 4.8 N/mm in DR. Furthermore, the DR + method resulted in a substantial reduction in the incidence of slippage of the tendon fibres out of the sutures and tendon bundles when compared with the DR suture.

Conclusions: The clinical problem of suture knots becoming loose within the tendon stump, leading to the failure of the tendon sutures, could be mitigated by additional augmentation, resulting in a substantial increase in ultimate load at failure. The benefits of the double-row transosseous-equivalent technique, which facilitates the pressing of the tendon stump against the footprint, are maintained. Level of Evidence Level of Evidence 5.