New Study: RSA Improves Meniscal Transplant Matching

Researchers from Houston Methodist Orthopedics & Sports Medicine reported in the December issue of the Orthopaedic Journal of Sports Medicine that a new technique using Roentgen Stereophotogrammetric Analysis (RSA) allows for the explanting and re-implanting of native meniscus to improve matching for lateral meniscus transplantation.

“One of the problems in doing meniscal transplant kinematic research is that we cannot get a sufficient number of clinically acceptable host-donor size and side matches, Patrick C. McCulloch, M.D., John S. Dunn Chair of Orthopedic Surgery at Houston Methodist Hospital in Houston, Texas, told OTW. “I may have 10 cadaver knees, but the likelihood of finding appropriate size matches would require that dozens more knees be screened. That is why we developed this novel technique of explanting the native meniscus with a sliver of bone after testing, embedding it in plastic with [RSA] beads, and re-implanting it as a ‘best case scenario’ perfect match.”

In this study, McCulloch and colleagues used RSA to evaluate the meniscus of eight cadaver knees at 0°, 30°, 90°, and 115° of knee flexion. Measurements were taken for three states: the native lateral meniscus, an anatomic autograft transplant and a nonanatomic autograft transplant with an anteriorized posterior root position.

According to the results, the largest lateral translation in the native state was 2.38 ± 1.58 mm at the anterolateral region from 0° to 90°, which was increased to 3.28 ± 1.39 mm (p= .25) and 3.12 ± 1.18 mm (p = .30) in the anatomic and nonanatomic transplant states. The native meniscus distributed load over 223 mm², while both the anatomic (160 mm²) and nonanatomic (102 mm²) states concentrated pressure anteriorly to the tibial plateau centroid.

“The study shows that the kinematics and contact pressures are partially restored to the native levels after transplantation and that subtle changes in root position result in measureable changes to each. Perhaps more importantly, I feel this study is a proof of concept that RSA can be used for meniscus research and that the development of this novel technique of allowing us to use the native meniscus as a transplant opens new avenues for meniscal research,” McCulloch said.

“The combination of RSA and the ability to get a perfect match by explanting and re-implanting the native meniscus will allow for much greater ability to improve and refine meniscal transplant surgery and potentially meniscal root repair.”