The Natural History of Medial Meniscal Root Tears: A Biomechanical and Clinical Case Perspective

Clinical outcomes following transtibial medial meniscal root repair are maintained at long-term follow-up

PURPOSE

To evaluate long-term outcomes of patients treated with posterior medial meniscal root tear (PMMRT) repair through assessment of functional outcome scores and to identify patient surgical and magnetic resonance imaging (MRI) characteristics associated with improved outcomes.

METHODS

This was a single-centre, retrospective study evaluating patients who had undergone a PMMR repair using a transtibial suture pullout technique with two locking cinch sutures. This was performed as a follow-up to previously published 2-year and 5-year outcome studies, using the same cohort. All patients from the prior short-term and midterm studies were invited to participate. Patient-reported outcome (PROs) scores, including the International Knee Documentation Committee (IKDC) and Lysholm scores, were collected. Previously collected demographic data were updated based on review of the electronic medical record. Patient outcomes were assessed preoperatively, as well as at 2-year, 5-year and 8-year postoperatively. MRI outcome measurements were assessed at 2-year and 5-year follow-ups. All statistical analysis was performed using SPSS version 26.

RESULTS

Seventeen patients of the original 18 patients (94.4%) were included in the final analysis. Additionally, three patients who had additional ipsilateral surgery were excluded from the analysis of PROs. The IKDC score significantly increased from 44.7 ± 11.6 at preoperative baseline to 71.2 ± 21.3 at 8-year post-operation (p = 0.001). There were no significant differences in IKDC score between 2-year and 8-year follow-ups (p = n.s.) or 5-year and 8-year follow-ups (p = n.s.). The Lysholm score significantly increased from 49.6 ± 7.3 at preoperative baseline to 76.4 ± 17.2 at 8-year follow-up (p < 0.001). There was no significant difference in Lysholm scores between 2-year and 8-year follow-ups (p = n.s.) or 5-year and 8-year follow-ups (p = n.s.). A linear regression analysis found that 5-year IKDC scores were significantly correlated with 8-year IKDC scores (β = 0.681, p = 0.038). At 8-year follow-up, four (23.5%) patients required additional procedures on their operative knee (one total knee arthroplasty conversion).

CONCLUSION

Patients treated with repair of PMMRT had maintenance of clinical outcome improvements at long-term follow-up despite worsening MRI outcomes at short-term and medium-term follow-ups. While a high proportion of patients required additional procedures on their operative knee at 8-year follow-up, few of these patient's additional procedures were related to failure of their primary surgery. Providers and patients may expect durable clinical outcomes following the repair of PMMRT, irrespective of radiographic appearance.

LEVEL OF EVIDENCE

Level IV.

The modified Nice knot has improved mechanical performance compared to the cinch stitch for meniscal root repair

PURPOSE

According to previous biomechanical studies, the success of meniscus root repair depends on the suture-meniscus interface and optimisation of this procedure seems to be critical. A progressive, reliable and adjustable knot has numerous advantages in meniscal repair since the surgeon can adapt and meticulously tune the final strength of the fixation. We hypothesised that a single passage of one tape at two different points of the posterior meniscal root with a modified Nice knot configuration may allow similar or superior fixation for root repair compared to the cinch stitch suture technique.

METHODS

Posterior root repair of medial and lateral meniscus was performed on 26 porcine knees. In group (A), two simple cinch stitches were applied, and in group (B), a modified Nice knot was used in a crossmatch configuration. For both groups, two passages through the meniscus with a 2-mm braided tape were used, and a single transosseous tibial tunnel technique was performed and tested in pull-out conditions.

RESULTS

The modified Nice knot showed an improved biomechanical performance considering the maximum failure load for both the medial (600.7 ± 77.5 N) and lateral (686.1 ± 83.5 N) (p = 0.006) posterior root fixation when compared to a double cinch stitch (558.0 ± 123.9 N) and (629.0 ± 110.2 N) (p = 0.178) for medial and lateral fixation, respectively. The maximum stiffness was also higher for the modified Nice knot configuration for both medial (17.1 ± 1.5 vs. 13.3 ± 1.6 N/mm) and lateral meniscus (20.0 ± 2.6 vs. 13.8 ± 2.3 N/mm), being this difference statistically significative (p = 0.001).

CONCLUSIONS

The modified Nice knot allowed better adaptation in the pull-out tests and presented higher fixation strength, stiffness and reproducibility, with lower standard deviation, being at the same time economically advantageous, since only one tape is needed.

LEVEL OF EVIDENCE

Level III.

Arthroscopic Transtibial Pullout Repair and Tibial Condylar Valgus Osteotomy for Medial Meniscus Posterior Root Tear With Varus Knee

As an important structure for maintaining the hoop tension of the medial meniscus of the knee joint, the posterior root is receiving increasing attention. Medial meniscus posterior root tear is an important reason for the occurrence, development, and kinematics changes of knee osteoarthritis. It is necessary to repair the posterior root of meniscus for restoring joint kinematics and improving clinical efficacy. This Technical Note reports a medial meniscus posterior root tear repair technique using arthroscopic transtibial pullout repair (ATPR) combined with tibial condylar valgus osteotomy. The aim of this technique is to repair the posterior root of the medial meniscus while correcting the force line through osteotomy, opening the joint gap, improving the joint surface fit, providing a good mechanical environment for meniscus repair, thereby improving the healing rate of the posterior root of the meniscus and reducing the risk of retear. Although clinical evidence is currently limited, we believe that this technology may have more clinical advantages compared with ATPR alone or ATPR combined with high tibial osteotomy.

Differences Between Traumatic and Degenerative Medial Meniscus Posterior Root Tears: A Systematic Review

BACKGROUND

Intact meniscus roots are a prerequisite for normal meniscal function, including even distribution of compressive forces across the knee joint. An injury to the root disrupts the hoop strength of the meniscus and may lead to its extrusion and the development of osteoarthritis. A medial meniscus posterior root tear (MMPRT) is often thought to have a primary degenerative pathogenesis. However, there is mention of some cases of MMPRTs where the patients have a solely traumatic injury to a previously healthy meniscus.

PURPOSE

To describe a subpopulation of patients with traumatic MMPRT.

STUDY DESIGN

Systematic review; Level of evidence, 5.

METHODS

The Web of Science database (www.webofscience.com) was queried using the Medical Subject Headings term "medial root tear." Articles were reviewed, and those evaluated for MMPRTs in a degenerative meniscus were excluded. A total of 25 articles describing cases of acute traumatic causes were included in this study. For these articles, the patient characteristics, injury mechanisms, and concomitant injuries evaluated were recorded and pooled.

RESULTS

The search revealed 660 articles, and 25 were selected for inclusion. A total of 113 patients with a traumatic MMPRT were identified and included in this review. The study population had a mean age of 27.1 years and a high share of men (64%). Also, this review displays how most patients with traumatic MMPRTs also suffer concomitant injuries (68%).

CONCLUSION

The findings in this review support our hypothesis that there is a unique subgroup with acute traumatic MMPRTs that have unique patient characteristics, injury mechanisms, and combined injuries, compared with previously published reviews on MMPRTs.

Meniscus root tears: state of the art

BACKGROUND

Meniscus root tears represent significant pathology that, historically, has been underdiagnosed and undertreated. However, the recognition of their clinical and functional significance has recently surged, mainly due to their frequent association with anterior cruciate ligament injuries.

AIM

This comprehensive review discusses various aspects of meniscal root tears, including their epidemiology, biomechanics, etiology, clinical and radiological findings, classification, management and surgical techniques.

Risk factors of incomplete healing following medial meniscus posterior root tear repair with gracilis tendon

To evaluate the clinical efficacy and meniscus healing rates of the arthroscopically assisted tendon graft fixation of the medial meniscus posterior root tears (MMPRTs), and to identify some independent risk factors correlated with meniscal root healing status. We conducted a retrospective study with 129 patients who received arthroscopically assisted tendon graft fixation of the MMPRTs between January 2018 and September 2021. Functional recovery of the knee was evaluated and meniscal root healing status was assessed. The associations between different clinical factors and meniscal root healing status were analyzed. 98 (76.0%) patients had complete meniscal root healing with a minimum 2-year follow-up, and the Lysholm score, international knee documentation committee score, and visual analogue scale score were significantly improved at final follow-up (P < 0.001; respectively). Binary logistic regression models analysis and the receiver operating characteristic curve was performed to detect independent risk factors for incomplete healing, and these results indicated that age (OR = 1.095, P = 0.039), body mass index (BMI) (OR = 1.259, P = 0.018), preoperative meniscus extrusion (OR = 5.181, P < 0.001) and varus degree (OR = 7.764, P < 0.001) were the independent risk factors correlated with incomplete healing in patients with repaired MMPRTs. In conclusion, the arthroscopically assisted tendon graft fixation of the MMPRTs can provide good clinical and radiological outcome. Additionally, we identified age > 37.5 years, BMI > 24.5 kg/m2, preoperative meniscus extrusion > 2.7 mm and varus degree > 3.3° as independent risk factors correlated with incomplete meniscus root healing status.

Editorial Commentary: High Tibial Osteotomy May Not Be Required With Medial Meniscus Root Repair

Meniscal root tears are defined as tears within 10 mm of their attachment and are more commonly observed in middle-aged patients. They have been named the silent epidemic and are equivalent to a total meniscectomy. Basic science studies have shown that posterior meniscus root repairs restore both contact area and pressure to its native state. The role of an additional high tibial osteotomy is not clear yet. High tibial osteotomies are commonly used to correct varus malalignment, a condition that is often observed with these tears. However, an additional osteotomy does not seem to offer any additional clinical benefits with regards to clinical and radiologic outcomes. It also has no effect with regards to contact pressure and contact area and is not related to the degree of deformity correction.

Failed transtibial pullout repair of the medial meniscus posterior root

Transtibial pullout repair is increasingly being utilized for repair of meniscal root tears. Loosening and suture pullout may occur after such a repair but has not been reported in the radiology literature. We present a case of a transtibial pullout repair complicated by suture pullout, recognized on MRI and confirmed on subsequent arthroscopy. This complication may occur in the immediate postoperative period and is important to recognize as it requires surgical management.

Knotless, Retensionable Posterior Meniscal Root Repair With Anterior Cruciate Ligament Repair TightRope and FiberRing Sutures

Posterior meniscal root repair techniques continue to evolve, influenced by rapidly increasing clinical interest, surgical technology advances, and biomechanical insights. A posterior meniscal root repair technique is presented, utilizing a knotless, retensionable suspensory construct developed for anterior cruciate ligament repair but is also well suited for meniscal root repair. Benefits include built-in shuttling sutures, knotless technology, and poststressing retensioning capability to ensure maximal final repair security.

Meniscus Root Tears: A Clinical Review

ABSTRACT

Meniscus root tears are important to recognize early given their potentially devastating consequences on joint health. This injury results in the lost ability of the meniscus to transfer axial loads into hoop stress; therefore, it is functionally equivalent to a complete meniscectomy. This causes rapid progression of osteoarthritis and increased need to total knee arthroplasty in a previously healthy joint. Despite these consequences, root tears have only been discussed in the orthopedic literature in the last 10 to 15 years and have not been routinely integrated into nonoperative sports medicine education. It is important for all nonoperative sports medicine providers to properly diagnose and triage this injury early in its course to maximize joint preservation efforts. The goal of this manuscript is to review the anatomy, presentation, natural history, imaging, and treatment options for meniscal root tears.