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Study Finds Docking Technique Yields Better Vascularity in UCL Reconstructions

Ulnar collateral ligament (UCL) reconstructions have not only been on the rise but so have their revisions. Different techniques have been developed to improve the success of this reconstruction, more commonly known as Tommy John surgery, yet no comparative clinical studies have examined the procedures head-to-head.

Today, researchers from Hospital for Special Surgery (HSS) presented study findings comparing the two leading techniques, Docking and the Modified Jobe, at this year’s annual meeting for the American Academy of Orthopaedic Surgeons (AAOS). This cadaver study has important clinical implications as both techniques are currently widely used by surgeons.

"While our results following Tommy John surgery are good, they’re not perfect," said Joshua S. Dines, MD, sports medicine surgeon at HSS and senior author. "Two ways that outcomes can be improved are through surgical techniques and post-operative rehabilitation - this study focuses on perfecting the surgical technique."

Some known reasons for why UCL reconstructions may fail include inadequate healing at the bone-tendon interface and bony fracture through drill tunnels.

The HSS study set out to determine how the two different reconstruction techniques affect intra-osseous blood flow to the medial epicondyle (ME) and sublime tubercle (ST), the critical sites for ligament graft healing. Additionally, the study looked to quantify vascular disruption caused by tunnel drilling in both techniques.

In the controlled laboratory experiment, eight matched pairs of upper extremities were assigned one of the two techniques, with the other paired elbow acting as a control.

After the surgeries, imaging (both MRI and CT) and statistical analysis revealed that drilling of the ulnar tunnels had a minimal impact on the intra-osseous vascularity of the ulna in both techniques.

However, blood flow to the ME was reduced by 14 percent with the Docking technique and 60 percent with the Modified Jobe, creating a mean difference of 46 percent. After the reduction, the Docking technique maintained 86 percent of blood flow while the Modified Jobe maintained only 40 percent.

"While the ideal amount of blood flow for optimal graft healing is unknown, we do know that more blood supply to the area is better," said Dr. Dines. "Our results showed that the Docking technique has the advantage over the Modified Jobe when it comes to vascularity. The more blood we can get to the affected area, the better the outcomes will be."

These findings can be applied in the operating room, not only for primary procedures, but for revisions as well.

The cause of failure after UCL reconstruction, in many cases, is multifactorial including returning to throwing too soon, poor throwing mechanics and inappropriate postoperative rehabilitation. Surgical factors may also contribute to the need for revision surgery if tendon to bone healing doesn’t occur to the extent that it should after the first procedure. Anything that can be done surgically to remove tendon to bone healing as a potential cause for surgical failure should be investigated further with the hopes that we continue to improve outcomes for Tommy John surgeries overall.

"We’re looking at each different part of the procedure to see how it can be improved. If, with each slight modification, we can increase the return to sport rate by 1 percent, then that’s a victory," said Dr. Dines who added that the research team is also looking at different ways to fix the graft to allow for better healing.