Medial Meniscus Posterior Root Repair Reduces but Does Not Avoid Histologic Progression of Osteoarthritis: Randomized In Vivo Experimental Study in a Rabbit Model

Abstract

Background: The optimal treatment option for meniscus root tears is still challenging, and whether the meniscus root repair ultimately can arrest or delay osteoarthritic changes is still a concern. Purpose/Hypothesis: The purpose of this study was 2-fold: (1) to describe and compare histopathologic findings of 3 different therapeutic options for medial meniscus posterior root tear: nonoperative management, partial meniscectomy, and meniscus root repair; and (2) to test the hypothesis that meniscus root tears treated nonoperatively predispose to a lower risk of osteoarthritic progression compared with partial meniscectomy. Study Design: Controlled laboratory study. Methods: Posteromedial meniscus root tears were carried out in 39 New Zealand White rabbits. Animals were randomly assigned into 3 experimental groups: partial meniscectomy after root tear (PM; n = 13), root tears treated conservatively (CT; n = 13), and transtibial root repair (RR; n = 13). Contralateral limbs were used as healthy controls. The animals were euthanized at 16 weeks postoperatively; tissue samples of femoral and tibial articular cartilage were collected and processed for macro- and microscopic assessment to detect signs of early osteoarthritis (OA). Each sample was histopathologically assessed using the Osteoarthritis Research Society International grading and staging system. Results: Osteoarthritic changes were the hallmark in all 3 experimental groups. The RR group had the lowest scores for cartilage damage (mean, 2.5; range, 2-3), and the PM group exhibited higher and more severe signs of OA (mean, 16; range, 9-16) compared with the CT group (mean, 5; range, 4-6). The between-group comparison revealed significant differences, as the PM group showed a significantly higher rate of macro- and microscopic osteoarthritic changes compared with the RR ( P < .001) and CT ( P < .001) groups. The weightbearing area of the medial femoral condyle was the most severely affected, and tidemark disruption was evident in all tissue samples. Conclusion: Meniscus root repair cannot completely arrest the histopathologic progression of knee OA but leads to significantly less severe degenerative changes than partial meniscectomy and nonoperative treatment. Partial meniscectomy leads to the most severe osteoarthritic progression, while stable radial tears left in situ have lower progression compared with partial meniscectomy. Clinical Relevance: Histologic assessment is an essential tool and metric for guiding and understanding osteoarthritic features, providing insight into the disease development and progression. This study provides histopathologic evidence on osteoarthritic progression after medial meniscus posterior root repair. This knowledge can help to set more realistic expectations and can lead to the future development of augmented techniques.

Osteoarthritis Development Following Meniscectomy vs. Meniscal Repair for Posterior Medial Meniscus Injuries: A Systematic Review

“…In light of our study's findings, the research conducted by Dzidzishvili et al provides compelling histopathologic insights into the treatment of meniscus root tears and its implications for osteoarthritic development, although in rabbit models, instead of humans [73]. The authors delineated the osteoarthritic changes across three experimental groups-partial meniscectomy, conservative treatment, and meniscus root repair-revealing that the repair group exhibited the least severe cartilage damage with a mean score of 2.5, compared to more pronounced OA signs in the meniscectomy group (mean score of 16) and the CT group (mean score of 5).…”

Accurate tibial tunnel position in transtibial pullout repair for medial meniscus posterior root tears delays the progression of medial joint space narrowing

“…Regardless, MMPR repair does not completely prevent the progression of osteoarthritis and medial joint space (MJS) narrowing [2,8,14]. While many similar studies have reported on postoperative MM extrusion (MME) progression [19,23,29], a previous study reported that MMPR repair slowed the progression of osteoarthritis compared with conservative treatment or meniscectomy in a rabbit model [3]. Factors such as age, weight, quadriceps muscle strength, healing status of the repaired posterior roots and time from symptom onset to surgery have been reported to influence the progression of MJS, MME and osteoarthritis in the postoperative period after MMPR repair [7,11,24].…”