Biomechanical testing of trans-humeral all-suture anchors for rotator cuff repair

Biocomposite Anchors Have Greater Yield Load and Energy Compared With All-Suture Anchors in an In Vitro Ovine Infraspinatus Tendon Repair Model

Purpose

To compare tensile fatigue and strength measures of biocomposite and all-suture anchors in an ovine humerus-infraspinatus tendon model of rotator cuff repair.

Methods

Infraspinatus tendons on adult ovine humeri were sharply transected at the insertion. One of each pair was assigned randomly for fixation with 2 biocomposite or all-suture anchors. Constructs were tested with 200 cycles of 20 to 70 N tensile load, and gap formation was measured at the incised tendon end every 50 cycles. They were subsequently tested to failure. Outcome measures including fatigue stiffness, hysteresis, creep, and gap formation and tensile stiffness, and yield and failure displacement, load, and energy were compared between anchors.

Results

Biocomposite anchors had greater yield load (134.1 ± 6.5 N, P < .01) and energy (228.6 ± 85.7 J, P < .03) than all-suture anchors (104.7 ± 6.5 N, 169.8 ± 85.7 J). Fatigue properties were not different between anchors, but stiffness and gap formation increased and hysteresis and creep decreased significantly with increasing cycle number.

Conclusions

Although the yield displacement of both anchors was within the range of clinical failure, the tensile yield load and energy of ovine infraspinatus tendons secured to the humerus with 2 single-loaded all-suture anchors in a single row were significantly lower than those secured with 2 biocomposite anchors in the same configuration.

Clinical Relevance

It is important to understand the biomechanical properties for selecting anchors for rotator cuff repair. A direct comparison of fatigue testing followed by failure strength of infraspinatus tendon fixation with all-suture and biocomposite anchors could help guide anchor selection and postoperative mobility recommendations.

Fast Arthroscopic Biceps Tenodesis Without Penetrating Grasper

Long head of the biceps pathology is a common cause of shoulder pain and dysfunction. Surgical treatment can be either a tenotomy or a tenodesis. Long-term results may be similar in both surgical techniques; however, the latest systematic reviews indicate that tenodesis offers superior clinical and functional results in young patients and athletes. Considering the favorable results with the biceps tenodesis, we present this arthroscopic tenodesis in which the long head of the biceps is fixed in the bicipital groove with an all-suture anchor passed directly through the tendon, providing a stable and fast fixation without using penetrating grasper.

All-Suture Anchors in Orthopaedic Surgery: Design, Rationale, Biomechanical Data, and Clinical Outcomes

All-suture anchors (ASAs) are a relatively new alternative to traditional suture anchors, comprised of sutures, suture tapes, or ribbons woven through a soft sleeve. These novel anchors are typically smaller than traditional anchors, allowing for more anchors to be used in the same amount of space or for use when bone stock is limited, for example, in revision settings. They can be inserted through curved guides to reach more challenging locations, and they have thus far had similar loads to failure during biomechanical testing as traditional anchors. However, these benefits must be weighed against new challenges. When using ASAs, care must be taken to fully deploy and seat the anchor against cortical bone for optimal fixation and to prevent gap formation. Furthermore, decortication, often performed to enhance the biologic environment for soft-tissue healing, may weaken the cortical bone on which ASA fixation depends on. The purpose of this article is to provide insight on the designs, advantages, and potential disadvantages associated with ASAs, as well as review the available biomechanical and clinical data.