Meniscal allograft transplantation. Part 2: systematic review of transplant timing, outcomes, return to competition, associated procedures, and prevention of osteoarthritis

To provide a systematic review of the literature regarding five topics in meniscal allograft transplantation (MAT): optimal timing for transplantation, outcomes, return to competition, associated procedures, and prevention of osteoarthritis. A systematic literature search was conducted using the PubMed (MEDLINE), ScienceDirect, and EBSCO-CINAHL databases. Articles were classified only in one topic, but information contained could be reported into other topics. Information was classified according to type of study (animal, in vitro human, and in vivo human) and level of evidence (for in vivo human studies). Specific inclusion criteria were determined for the outcomes and prevention of osteoarthritis topics. Twenty-four studies were finally included: two optimal timing, seven outcomes, three return to competitive sport, 16 MAT and associated procedures, and 5 MAT and prevention of osteoarthritis (some studies were categorized in more than one topic). These studies corresponded to 2 animal studies and 31 in vivo human studies (1 level II, 1 level III, and 29 level IV). The principal conclusions were as follows: (a) there is no evidence to support that MAT has to be performed at the same time or immediately after meniscectomy to prevent development of postmeniscectomy syndrome; (b) MAT successfully improves symptoms, function, and quality of life at 7-to-14 years of follow-up (level IV evidence); (c) the overall failure rate (need for knee arthroplasty) is 10-29 % at long-term follow-up; (d) MAT allows return to same level of competition in 75-85 % of patients at short- to mid-term follow-up (only three studies level IV evidence with small sample size); (e) associated cartilage procedures or anterior cruciate ligament reconstruction to MAT does not worsen the results; (f) MAT may prevent progression of cartilage damaged at long-term follow-up, but may not prevent degeneration in previously healthy cartilage. Systematic review of level II-IV studies, Level IV.