Introduction - Meniscus transplantation is indicated for patients with a symptomatic meniscus deficient knee which is well aligned and stable. Initially MAT was indicated for patients with intact cartilage surfaces however the indications have been extended to include the treatment of instability and knees with greater degrees of chondral wear.
Content - A recent Meta-analysis have reported that 85.8% of medial and 89.2% of lateral meniscal allograft transplants survive at midterm (5-10 years) while 52.6% of medial and 56.6% of lateral meniscal allograft transplants survive long term (>10 years). Functional outcomes 10 years after MAT are fair and improved compared with preoperative scores. Patients undergoing lateral MAT have demonstrated greater pain relief and functional improvement than patients undergoing medial MAT. MAT is associated with a significant re-operation rate of up to 20% and patients need to be counselled accordingly.
The majority (77%) of athletes and physically active patients are able to return to sport after MAT; approximately two-thirds are able to perform at preinjury levels. Most studies have reported no significant differences between the soft tissue suture and bone fixation in terms of meniscal allograft tear rates, failure rates, Lysholm scores, and VAS scores. Meniscal extrusion is also similar with both techniques.
Associated malalignment and ligamentous instability should be corrected and overall, there seems to be no significant difference between the postoperative patient reported outcome scores in terms of isolated MAT and MAT combined with other procedures i.e. ligament reconstruction, osteotomy. However, more data is required to verify the effects of osteotomy and cartilage procedures on the clinical outcomes of MAT.
More latterly the importance of the meniscus in knee instability has been appreciated and thus the potential role of MAT. Medial MAT has been shown to improve not only anteroposterior stability but also rotational stability in the meniscus-deficient ACL-reconstructed knee. Lateral MAT showed improvements in the anterior drawer and Lachman tests but not in the pivot-shift test or side-to-side difference on Telos stress radiographs in meniscus-deficient ACL-reconstructed knees.
There is currently insufficient data within the literature to state whether MAT is chondroprotective or cost-effective. MAT needs to be approximately one-third more effective in delaying OA in previously meniscectomized knees to be considered cost-effective. Younger, non-obese patients have the lowest required efficacy of MAT to be cost-effective.