Lateral meniscus posterior root repairs show superior healing, reduced meniscal extrusion and improved clinical outcomes compared to medial meniscus posterior root repairs: A systematic review.

PURPOSE: To systematically review and summarize the available literature on (1) postoperative healing rates, meniscal extrusion (ME) and clinical outcomes following lateral (LMPRR) versus medial (MMPRR) root repair and (2) potential correlations between residual ME and healing outcomes. METHODS: A comprehensive literature search was conducted using the Scopus, PubMed and Embase databases. Clinical studies evaluating healing status on second-look arthroscopy and magnetic resonance imaging (MRI) after LMPRR and MMPRR were included. Study quality was assessed using the Methodological Index for Non-Randomized Studies criteria and the modified Coleman Methodology Score. RESULTS: Twenty-three studies comprising 871 patients with LMPRR (n = 406) and MMPRR (n = 465) were included. Overall, 223 (54.9% of total) and 149 (32.04% of total) patients underwent second-look arthroscopy in the LMPRR and MMPRR groups, respectively. Complete root healing was observed in 190 (85.2%) patients in the LMPRR group versus 78 (52.3%) in the MMPRR group (p < 0.001). There were six (2.7%) failed repairs in the LMPRR group compared to 21 (14.09%) in the MMPRR group (p < 0.001). On postoperative MRI, 109 (75.7%) root repairs were healed in the LMPRR group compared to 192 (53.3%) in the MMPRR group (p < 0.001). Failure rates were lower after all-inside and transtibial pullout repairs in the LMPRR group but higher in the MMPRR group, with no significant mean difference between preoperative and postoperative ME in the MMPRR group (p = 0.95). Significantly better clinical outcomes were observed in the LMPRR group compared to the MMPRR group. A greater degree of postoperative ME was associated with lower healing rates (R = -0.78, p < 0.0005). Postoperative ME did not influence clinical outcomes (R = 0.28, p = 0.29). CONCLUSIONS: Lateral meniscus posterior root repairs showed higher healing rates compared to MMPRR on both second-look arthroscopy and postoperative MRI. Meniscal extrusion decreased after LMPRR but not after MMPRR. Greater residual ME correlated inversely with healing rates, as more extrusion was associated with lower healing. Postoperative clinical improvement did not affect ME or healing status. STUDY DESIGN: Systematic review of level III and IV studies. LEVEL OF EVIDENCE: Level IV.

Increased Posterior Tibial Slope Is Associated With Increased Risk of Meniscal Root Tears: A Systematic Review.

BACKGROUND: While increased posterior tibial slope (PTS) is an established risk factor for anterior cruciate ligament tears, the association between tibial slope and meniscal posterior root tears is not well-defined. PURPOSE: To summarize the available literature evaluating the association between PTS and meniscus root injuries compared with patients without root tears. STUDY DESIGN: Systematic review; Level of evidence, 4. METHODS: A literature search was performed using the Scopus, PubMed, and Embase databases. Human clinical studies evaluating the associations between the medial tibial slope (MTS), lateral tibial slope (LTS), lateral-to-medial (L-to-M) slope asymmetry, and the risk of meniscus root tears were included. Patients with medial meniscus posterior root tears (MMPRTs) and lateral meniscus posterior root tears (LMPRTs) were compared with a control group without root injury. Study quality was assessed using the methodological index for non-randomized studies criteria. RESULTS: Ten studies with 1313 patients were included (884 patients with root tears; 429 controls). The LMPRT subgroup (n = 284) had a significantly greater LTS (mean ± SD, 7.3°± 1.5° vs 5.7°± 3.91°; P < .001), MTS (5.26°± 1.2° vs 4.8°± 1.25°; P < .001), and increased L-to-M asymmetry (2.3°± 1.3° vs 0.65°± 0.5°; P < .001) compared with controls. The MMPRT group (n = 600) had significantly increased MTS relative to controls (8.1°± 2.5° vs 4.3°± 0.7°; P < .001). Furthermore, there was a higher incidence of noncontact injuries (79.3%) and concomitant ramp lesions (56%) reported in patients with LMPRT. CONCLUSION: Increased MTS, LTS, and L-to-M slope asymmetry are associated with an increased risk of LMPRTs, while increased MTS is associated with MMPRTs. Surgeons should consider how proximal tibial anatomy increases the risk of meniscus root injury.

An anatomical study of the meniscal roots of the knee: landmarks for its surgical reconstruction and implications for knee surgeons.

PURPOSE: The aim of this anatomical study was to describe the anatomy of the meniscal roots and their relationships with respect to the main adjacent structures in order to improve their surgical reconstruction. METHODS: Fourteen knees were included. The mean age of the donors was 92 years (range 89-96). We studied the general characteristics of the anterior and posterior roots of the medial meniscus and lateral meniscus by measuring their widths at their base and area. We investigated the relations between anterior and posterior roots of the medial and lateral menisci with respect to the anterior and posterior cruciate ligaments (ACL and PCL). RESULTS: The mean width of the anterior root of the lateral meniscus was 10.5 ± 1.4 mm. The mean width of the anterior root of the medial meniscus was 10 ± 1.5 mm. The mean width of the posterior root of lateral meniscus was 11.4 ± 1.4 mm. The mean width of the posterior root of medial meniscus was 10.5 ± 1.0 mm. The mean distance between the anterior cruciate ligament and the anterior root of lateral meniscus was 9.8 ± 2.9 mm, for the medial meniscus it was 15.9 ± 3.4 mm. The mean distance between the posterior cruciate ligament and the posterior root of the lateral meniscus was 11.5 ± 2.7 mm, for the medial meniscus, it was 11 ± 2.6 mm. CONCLUSION: The anterior and posterior meniscal roots have precise landmarks, and this article contributes to define the location of the meniscal roots with respect to their adjacent anatomical structures: ACL, PCL and intercondylar tubercle. Having precise measures of the distances between the meniscus roots and these structures allows knee surgeons to perform ACL reconstruction, meniscal root repair and meniscal allograft transplantation.

The menisci and articular cartilage: a life-long fascination.

The menisci and articular cartilage of the knee have a close embryological, anatomical and functional relationship, which explains why often a pathology of one also affects the other.Traumatic meniscus tears should be repaired, when possible, to protect the articular cartilage.Traumatic articular cartilage lesions can be treated with success using biological treatment options such as microfracture or microdrilling, autologous chondrocyte transplantation (ACT), or osteochondral transplantation (OCT) depending on the depth and area of the lesion.Degenerative cartilage and meniscus lesions often occur together, and osteoarthritis is already present or impending. Most degenerative meniscus lesions should be treated first conservatively and, after failed conservative treatment, should undergo arthroscopic partial meniscus resection. Degenerative cartilage lesions should also be treated conservatively initially and then surgically; thereby treating the cartilage defect itself and also maintaining the axis of the leg if necessary.Tears of the meniscus roots are devastating injuries to the knee and should be repaired e.g. by transtibial re-fixation.The clinical role of 'ramp' lesions of the meniscus is still under investigation. Cite this article: EFORT Open Rev 2020;5:652-662. DOI: 10.1302/2058-5241.5.200016.

Early Osteoarthritis After Untreated Anterior Meniscal Root Tears: An In Vivo Animal Study.

BACKGROUND: Meniscal root tears cause menisci and their insertions to inadequately distribute loads and potentially leave underlying articular cartilage unprotected. Untreated meniscal root tears are becoming increasingly recognized to induce joint degradation; however, little information is known about anterior meniscal root tears and how they affect joint tissue. PURPOSE: To observe the early degenerative changes within the synovial fluid, menisci, tibial articular cartilage, and subchondral bone after arthroscopic creation of untreated anterior meniscal root tears. STUDY DESIGN: Controlled laboratory study. METHODS: Anterolateral meniscal root tears were created in 1 knee joint of 5 adult Flemish Giant rabbits, and anteromedial meniscal root tears were created in 4 additional rabbits. The contralateral limbs were used as nonoperated controls. The animals were euthanized at 8 weeks postoperatively; synovial fluid was aspirated, and tissue samples of menisci and tibial articular cartilage were collected and processed for multiple analyses to detect signs of early degeneration. RESULTS: Significant changes were found within the synovial fluid, meniscal tissue, and tibial subchondral bone of the knees with anterior meniscal root tears when compared with controls. There were no significant changes identified in the tibial articular cartilage when comparing the tear groups with controls. CONCLUSION: This study demonstrated early degenerative changes within the synovial fluid, menisci, and tibial subchondral bone when leaving anterior meniscal root tears untreated for 8 weeks. The results suggest that meniscal tissue presents measurable, degenerative changes prior to changes within the articular cartilage after anterior meniscal root tears. Anterior destabilization of the meniscus arthroscopically may lead to measurable degenerative changes and be useful for future in vivo natural history and animal repair studies. CLINICAL RELEVANCE: The present study is the first to investigate various tissue changes after anterior meniscal root tears of both the medial and lateral menisci. The results from this study suggest that degenerative changes occur within the synovial fluid, meniscus, and tibial subchondral bone prior to any measurable changes to the tibial articular cartilage. Further studies should expand on this study to evaluate how these components continue to progress when left untreated for long periods.

Anatomy of the anterior root attachments of the medial and lateral menisci: a quantitative analysis.

BACKGROUND: While the biomechanical importance of the meniscal roots has been demonstrated, the anatomy of the anterior meniscal roots remains largely unknown. Defining the quantitative anatomy of the anterior meniscal root attachments is essential for developing improved diagnostic and surgical techniques. HYPOTHESIS: The anterior medial (AM) and anterior lateral (AL) meniscal roots could be quantitatively defined relative to open and arthroscopic surgical landmarks. STUDY DESIGN: Descriptive laboratory study. METHODS: Twelve nonpaired human cadaveric knees were used (average age, 51.3 years). A coordinate measuring device quantified the anatomic relationships of the AM and AL root attachments to open and arthroscopic surgical landmarks. The tibial attachments of both anterior roots were defined and quantified by categorizing the fibers of the root as either central, dense attachments or peripheral, supplemental attachments. RESULTS: The center of the tibial tuberosity and the medial tibial eminence apex were 27.0 mm lateral and distal and 27.5 mm posterior to the center of the AM root, respectively. The center of the anterior cruciate ligament (ACL) and the lateral tibial eminence apex were 5.0 mm posteromedial and 14.4 mm posterolateral to the center of the AL root, respectively. The AM root attachment had a mean area of 110.4 mm(2) (95% CI, 92.2-128.5) with a central attachment of 56.3 mm(2) (95% CI, 46.9-65.8). The AL root attachment had a mean area of 140.7 mm(2) (95% CI, 121.6-159.8) and inserted deeply beneath the ACL in all specimens. The overlap of the ACL on the AL root averaged 88.9 mm(2) (95% CI, 63.3-114.6), comprising 63.2% of the AL root attachment. CONCLUSION: The anterior meniscal roots were identified in relation to pertinent open and arthroscopic landmarks. The extended overlap between the AL root and ACL attachment revealed a more intimate tibial attachment relationship than previously recognized. CLINICAL RELEVANCE: Quantitative descriptions of the anterior meniscal roots elucidate the relationship between the root attachments and pertinent surgical landmarks. In addition, the supplemental attachments of both menisci may contribute to native meniscal function, and further investigation is recommended.