Metacarpophalangeal collateral ligament reconstruction using small intestinal submucosa in an equine model.

The study investigates the use of small intestinal submucosa (SIS) from pigs for repair of collateral ligament damage in horses. It shows that SIS, when used as a scaffold in surgery, can effectively restore joint stability and improve the quality of early-stage healing tissue.

Objective of the Study

• The goal of this research was to explore the effectiveness of small intestinal submucosa (SIS)—a natural, biodegradable material sourced from pigs—as a scaffold for surgically repairing damaged collateral ligaments in horses. Specifically, the study aimed to evaluate whether an SIS-anchored ligament would prove superior to a sham-operated control in correcting joint laxity.

Study Design and Methodology

• Ten horses, each having a complete transection of the lateral collateral ligament in the metacarpophalangeal joint, were part of the study.
• In six of these animals, the collateral ligament was reconstructed using a multilaminate strip of SIS. The SIS strip was secured with screws driven into bone tunnels at either end of the joint.
• The remaining four horses were sham controls: they underwent the same procedure, but with no SIS implanted.
• Investigations carried out included: assessing lameness, analyzing incision quality, and measuring joint range of motion, circumference, and laxity. Ligament structure and strength were also quantified through ultrasound, histology, and mechanical testing 8 weeks post-surgery.

Key Findings

• Surgical repair with SIS eliminated joint laxity immediately post-surgery.
• At the 8-week mark, SIS-treated joints exhibited significantly less laxity than the sham-treated joints.
• Ligaments treated with SIS demonstrated progressive improvement in repair tissue density and fiber alignment over 8 weeks and these parameters significantly outperformed those of the sham-treated ligaments.
• SIS-repaired ligaments tended to handle greater stress to failure than sham-treated ones, although this result narrowly missed statistical significance.
• Ligament repair tissue and bone tunnel inflammation were significantly more pronounced in the SIS-treated limbs.

Conclusion

• The study concludes that SIS implants might be biocompatible in the joint environment, capable of restoring initial loss of joint stability, and capable of enhancing the quality of early repair tissue during the first 8 weeks of ligament healing.
• As such, SIS ligament reconstruction may be beneficial for early ligament healing and in promoting early joint stability associated with ligament injury.