Factors predicting meniscal repair success.

Pathologic Characteristics of the Torn Human Meniscus.
Mesiha, M., Zurakowski, D., Soriano, J., Nielson, J., Zarins, B. and Murray, M. American Journal of Sports Medicine, 2007; 35: 103 – 112.
http://www.ncbi.nlm.nih.gov/pubmed/17092929

Due to its avascularity, meniscus has poor healing characteristics. Currently, surgeons opt to preserve as much meniscus tissue as possible to prevent early OA changes in the knee joint therefore one of the surgical methods to deal with this type of lesion, is meniscal repair. However, lack of information exists on patient related factors that could help identify tears at higher risk for repair failure. Cellularity of the meniscus is one of the factors that determine repair failure or success. The study was conducted to investigate whether specific patients related factors including patient age, time since injury, and tear type are related to the cellularity of torn meniscus tissue.
Forty-four torn menisci were collected from patient’s ages 18 to 76 years at the time of arthroscopic meniscectomy. Authors found that age, time since injury and tear type all had significant effects on the histologic characteristics of the torn meniscus. Specifically, those older than 40 years, with degenerative or radial tear type and longer injury history had decreased intrinsic and perimeniscal cellularity in their torn menisci.
Although patients >40 years old have good short term clinical success after meniscal repair, it is reported that long –term effectiveness is low which, according to authors might be associated with the decreased intrinsic and perimeniscal cellularity in their meniscus in these group.
In regards to time since injury, authors suggest that although meniscus cells are capable of surviving some period after injury there might be a critical point when cell death occur.
Finally, authors observed that radial and degenerative tear types were associated with a significantly higher rate of articular cartilage change. Also, they reported formation of a synovialized, cell-dense, perimeniscal layer (associated with successful meniscus healing in animal models) in longitudinal tears, but not in the degenerative tear type.
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