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CMI allows moderate to extensive defect filling
Patients regain 60% of lost activity. Tissue maturation still going at one year.
Investigators found that collagen meniscus implants support new tissue growth in patients who previously underwent one to three partial medial meniscectomies.
William G. Rodkey, DVM, at the Steadman Hawkins Research Foundation and Clinic in Vail, Colo., presented the findings at the recent 6tth International Cartilage Repair Society (ICRS) annual meeting. Their study involved 21 patients aged 18 to 60 years. Of these, 12 patients were randomized to receive collagen meniscus implants (CMI) and nine to receive partial meniscectomy. The gender distribution between groups was almost identical; the only difference being that the control group tended to have a higher body mass index (BMI).
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COURTESY: WILLIAM G. RODKEY |
“Our goals were to regenerate/re-grow new meniscus-like tissue in order to slow down and prevent further degenerative joint disease, enhance joint stability, provide pain relief and, the big thing, to return patients to activity at the level they wish to get back to,” said Rodkey, a member of the Steadman Hawkins Scientific Advisory Board.
Researchers attempted to replace the defects that occurred after loss of meniscal tissue using the tissue engineering approach. The goal was to fill the defect with the CMI to allow cells to migrate into it and, over time, the new tissue would grow and regenerate.
Researchers measured meniscal defect sizes at the time of the first surgery. They then calculated the percent of meniscus lost from the measurements. The CMI was sutured into place and attached to the host using an inside out technique.
Researchers performed “relook arthroscopy” in CMI patients after one year. They used the sutures that remained as a landmark to help determine the amount of new tissue. A calibrated probe was used to measure the extent meniscal defects filled with new tissue.
“What we saw with this new CMI-regenerated tissue was that most had moderate-to-extensive filling of the defect, most had fibrochondral tissue that was meniscus-like in appearance, and we did see that the maturation process was still ongoing at one year,” Rodkey said.
CMI patients lost roughly 77% of their meniscus and the controls lost about 75%. At one year, CMI patients had their defects 71% filled and, based on historical control data, the authors assumed the corresponding percentage in control patients to be zero. CMI patients ended up with 78% of their meniscus whereas controls had 25%.
Researchers calculated the percent of meniscus gained by multiplying the percent meniscus lost by percent defect filled, and then dividing that product by the difference of 100%, less percent meniscus loss, according to the abstract. The CMI patients gained roughly 238%.
The main question these results led authors to: “Does this new tissue function?”
“What we saw was that the CMI patients regained 60% of activity that they had lost as a result of their injury, whereas the control patients had continued to deteriorate and had actually lost another 18%,” Rodkey said.
The authors concluded that CMI supports new tissue formation that fills meniscal defects. The percent of meniscus gained and the total amount of meniscal tissue in CMI patients after one year are significant compared to partial meniscectomy alone, they said.
For more information:
- Rodkey WG, Steadman JR, Briggs KK. Tissue gain after placement of a collagen meniscus implant following partial meniscectomy. Presented at the ICRS meeting Jun. 8-11, 2006. San Diego.