Satisfactory Clinical Outcome, Complications, and Provisional Results of Meniscus Centralization with Medial Meniscus Root Repair for the Extruded Medial Meniscus at Mean 2-Year Follow-Up

Centralization reduces meniscal extrusion, improves joint mechanics and functional outcomes in patients undergoing meniscus surgery: A systematic review and meta-analysis

PURPOSE

To perform a systematic review and meta-analysis of the existing literature on meniscal centralisation procedures, analysing its impact on meniscal extrusion, joint biomechanics and clinical and radiological outcome measures.

METHODS

The Cochrane Controlled Register of Trials, PubMed (MEDLINE) and Embase were used to perform a systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. Biomechanical studies on healthy animal or human cadaveric knee joints that assessed meniscal extrusion or tibiofemoral contact mechanics (contact area and pressure) following centralization for meniscal pathologies were included. For clinical studies, those that prospectively or retrospectively assessed patient-reported outcome measures (PROMs), postoperative knee motion, complications and radiological extrusion following centralization for meniscal pathologies were included.

RESULTS

Fifteen studies were included in the analysis, comprising eight biomechanical, six clinical and one both. There were 92 knee specimens for biomechanical testing, of which 40 were human cadaveric and 52 porcine models. Biomechanical data revealed centralization to be commonly performed for posterior meniscal root tears and significantly reduced extrusion and contact pressure whilst improving contact area following a tear (p < 0.00001). Centralization restored extrusion to that of the native knee at all flexion angles described (0-90°, p = 0.25) and, compared to the torn state, brought tibiofemoral contact mechanics 3.2-5.0 times closer to the native state. Clinical data showed that 158 patients underwent centralization for extrusion. It improved postoperative Knee Injury and Osteoarthritis Outcome score (KOOS) (p = 0.006) and Lysholm scores (p < 0.00001) at 25.0 months, maintained extrusion reduction at 17.1 months (p < 0.00001) and preserved knee motion.

CONCLUSION

Centralisation for various meniscal injuries associated with extrusion can reduce meniscal extrusion and improve joint biomechanics, along with clinical and radiological outcomes. Existing evidence is still scarce and exhibits a notable amount of methodological heterogeneity.

LEVEL OF EVIDENCE

Systematic review of Level IV evidence.

Review of the Development of Meniscus Centralization

PURPOSE OF REVIEW

With an aging population, extending healthy life expectancy is a global challenge. Maintaining healthy knee joint function is one of the essential factors to preserve the ability to walk and extend healthy life expectancy. Meniscus centralization was introduced in 2012 as a procedure for meniscus extrusion, one of the causes of knee osteoarthritis (OA). Initially, it was performed only for lateral meniscus (LM) extrusion, and favorable 2-year results were reported in 2016. Gradually, basic studies supporting the effectiveness of meniscus centralization have been reported, and it has also been performed for medial meniscus (MM) extrusion, with some positive results reported. Although the surgical procedures vary among the institutions, the basic concept is to reattach the loosened meniscotibial ligament to the edge of the tibial plateau to re-tension it. This review will discuss the history of development and the current status of meniscus centralization.

RECENT FINDINGS

Current research shows that meniscus centralization is not performed in isolation but is often used as an augmentation along with the conventional repair of meniscus injuries, particularly posterior root tears. Biomechanical studies demonstrated that MM centralization with a posteromedial anchor can better restore meniscus function.

CONCLUSION

Despite its relatively short publication history of just over ten years, meniscus centralization has shown potential as a treatment to curb the progression of knee OA and extend a healthy life. While more evidence is needed, this conclusion underscores the promising role for meniscus centralization, making it a topic of significant interest for knee surgeons and researchers.

The association of the medial meniscus covering ratio with knee cartilage thickness at 15 medial compartment subregions as found by three-dimensional analysis using MRI

Purpose

The correlation of cartilage thickness measured by three-dimensional (3D) magnetic resonance imaging (MRI) and the medial meniscal coverage ratio (MMCR), which presented pathology of the medial meniscus extrusion (MME) in 3D MRI, has not yet been elucidated. The study's purpose was to retrospectively verify whether the average cartilage thickness calculated by the automatic MRI 3D analysis system for each subregion was correlated with MMCR.

Methods

A total of 60 patients underwent medial meniscus repair or high tibial osteotomy to treat their medial knee osteoarthritis. Cartilage thickness and MMCR were automatically calculated using 3D MRI software. The MMCR was defined as the ratio of the area covered by the meniscus within the medial tibial cartilage area to the total medial tibial cartilage area. The association between MMCR and the average cartilage thickness at 15 subregions in the medial femoral condyle (MFC) and medial tibial plateau (MTP) was evaluated using Spearman's rank correlation coefficient.

Results

Kellgren-Lawrence grade exhibited a negative correlation with MMCR and a positive correlation with MME width. Cartilage thickness in the MTP had a moderately positive correlation with MMCR at four subregions and a weakly positive correlation at another subregion. Cartilage thickness in the MFC showed a moderately positive correlation with MMCR at five subregions and a weakly positive correlation at one subregion.

Conclusions

Cartilage thickness calculated by automatic MRI 3D analysis system had a positive correlation with MMCR for all subregions of the anterior and middle subregions in the MFC and for five regions of nine subregions of the anterior and middle subregions in the MTP.

Level of evidence

Level II, cross-sectional study (diagnosis).

Editorial Commentary: Early Clinical Results Are Promising for Meniscus Centralization as an Augment to Medial Meniscus Root Repair

Meniscal root tears remain a common problem, with devastating biomechanical and clinical consequences. Thankfully, numerous techniques have been developed to repair the symptomatic meniscal root tear. However, rates of conversion to arthroplasty are reported to be 21% to 33% at 10 years, and persistent extrusion of the meniscus at follow-up is a known limitation of current root repair techniques. There is also growing evidence that some medial meniscal root tears may be an effect of meniscal extrusion, rather than the cause of it. In that vein, failure to correct extrusion may be a key mechanism of clinical and radiographic failure despite successful meniscus root repair. Techniques that "centralize" the meniscus (such as centralization with anchors at the tibial rim, meniscotibial ligament repair, deep medial collateral ligament repair, or circumferential suture augmentation of the meniscus) may improve patient outcomes by better correcting meniscal extrusion. Indications could be extrusion greater than 3 mm and documented extrusion before the root tear.

All-Soft-Tissue Meniscus Allograft Transplantation With Circumferential Suture Tape Augmentation to Mitigate Hoop Stress and Promote Centralization

Meniscus allograft transplantation (MAT) is a technically challenging procedure. Bone plugs, slot techniques, and all-soft-tissue fixation techniques have been described in the past. Each technique comes with advantages and disadvantages. Native menisci have circumferential collagen fibers to help resist hoop stress during loading cycles. Although hoop stress resistance is a known function of the menisci, its recreation in MAT has only been targeted indirectly through anatomic root placement. The authors describe the use of a high-tensile suture tape (i.e. InternalBrace) to promote centralization by directly mitigating hoop stresses through recreation of peripheral meniscus tensioning in MAT.