A Meta-Analysis of Arthroscopic Meniscal Repair: Inside-Out versus Outside-In versus All-Inside Techniques

Meniscal repair has been introduced to preserve knee function and limit the accelerated degenerative changes associated with meniscal tissue resection. Arthroscopic techniques have evolved to improve morbidity. However, there are few clinical outcome studies in the peer-reviewed literature that compare the use of these approaches. Therefore, our purpose was to perform a meta-analysis of the existing literature on arthroscopic meniscal repair techniques. Specifically, we evaluated differences in: (1) operating time; (2) incidence of postoperative meniscal healing; (3) functional outcomes, using various scoring systems; and (4) incidence of complications. We searched the peer-reviewed literature using SCOPUS, Medline, EMBASE, and Web of Science. Eight studies were eligible for the meta-analysis. These included one prospective, randomized trial (level I), three prospective, comparative studies (level II), and four retrospective, comparative studies (level III). There were a total of 476 patients who had a mean follow-up between 3 and 156 months. When evaluating objective outcomes, the inside-out technique had a significantly higher mean operating time than the all-inside technique. The inside-out and all-inside techniques had comparable meniscal healing rates, but the outside-in repair had a significantly higher rate of meniscal healing than the all-inside repair. Upon assessment of functional outcomes, the inside-out and all-inside methods had comparable International Knee Documentation Committee and Tegner activity scores, but the all-inside method had greater improvements in Lysholm scores. The inside-out and all-inside repairs had similar overall complication rates. All-inside repair may demonstrate lower operating times, but the outside-in repair may have superior meniscal healing rates. Functional outcomes are overall comparable between the techniques. However, there are limited clinical data on the outcome differences between these procedures, and further comparative studies with longer follow-up are needed.