H-Plasty Repair Technique Improved Tibiofemoral Contact Mechanics After Repair for Adjacent Radial Tears of Posterior Lateral Meniscus Root: A Biomechanical Study

Incomplete histologic healing and diminished biomechanical strength of meniscus-bone interface after medial meniscus posterior root transosseous repair in a goat model

PURPOSE

To enhance the understanding of histological healing after repairing medial meniscal posterior root tear (MMPRT) at an early stage, utilizing a goat model.

METHODS

Eighteen adult goats, totaling thirty-six knee joints, were allocated into three groups (n = 12): Sham group (Sham), Root Tear group (RT), and Root Tear with Transosseous Suture group (RTS). At 12- and 24-week intervals post-surgery, all the knees were harvested for imaging, macroscopic, histological, and biomechanical assessments.

RESULTS

The intact root served as a meniscus-bone interface which connected the tibial and the circular fibers of the meniscus, with a bony insertion and a root-meniscus transition. A direct-fibrous-connection displayed at the bony insertion proximal to the synovium in the RTS group, while the remaining regions of the root displayed indirect-fibrous healing. The healing in the RT group was disjointed and reminiscent of scar tissue. The RTS group exhibited a more pronounced coronal extrusion compared to the Sham group (0.42 ± 0.09 vs. 0.19 ± 0.02, P = 0.0012) but was improved relative to that of the RT group (0.49 ± 0.02, P = 0.0028). The failure load and stiffness of the RTS group were notably higher than those of the RT group, with a strength of 42.67% and a stiffness of 83.75% of the intact root. All the samples ruptured at the root-meniscus transitions.

CONCLUSION

The incomplete healing may be attributed to the histological factors underlying the low healing rate and persistent MME. Notably, the region attached to the posterior-cruciate-ligament exhibited superior healing compared to other regions of the bony insertion in the repaired group. Conversely, the root-meniscus transition displayed discontinuity, representing a mechanical weakness in the healing process.

CLINICAL RELEVANCE

Modifications of bone tunnel positioning and suture placement could be undertaken in subsequent studies to particularly enhance the healing of the root-meniscus transition.

Steep Posterior Tibial Slope and Excessive Anterior Tibial Translation Are Associated With Increased Sagittal Meniscal Extrusion After Posterior Lateral Meniscus Root Repair Combined With Anterior Cruciate Ligament Reconstruction

Purpose

To (1) evaluate the clinical and radiographic outcomes of patients with primary anterior cruciate ligament reconstruction (ACLR) with type II posterior lateral meniscus root tear (PLMRT) repair and (2) identify whether increased anterior tibial subluxation of the lateral compartment (ATSLC) and steeper posterior tibial slope (PTS) are associated with sagittal lateral meniscal extrusion (LME).

Methods

Patients who underwent primary anatomic ACLR with concomitant type II PLMRTs using the all-inside side-to-side repair technique between November 2014 and September 2020 were identified. To be included, patients must have had a minimum of 2 years follow-up. All patients, including those with ATSLC and PTS and sagittal and coronal LME, were retrospectively reviewed clinically and radiologically. The patients were divided into 2 subgroups according to the occurrence of sagittal LME.

Results

Forty patients were included in this study with a mean follow-up of 44 months (range, 24-94 months). In general, the postoperative parameters, including grade of pivot shift, side-to-side difference, ATSLC, Lysholm score, and International Knee Documentation Committee (IKDC) score, were significantly improved compared with the preoperative ones. However, postoperative sagittal LME was detected to be significantly larger than the preoperative one. Minimal clinically important difference (MCID) analysis for postoperative outcomes showed that the rate of patients who achieved MCID thresholds was 100% for Lysholm, 95% for IKDC, 42.50% for coronal LME, 62.50% for sagittal LME, 40% for ATSLC, and 100% for side-to-side difference. Further comparisons, where patients were divided into 2 subgroups according to the occurrence of sagittal LME, showed significant differences in PTS, ATSLC, and coronal LME.

Conclusions

Clinical outcomes after type II PLMRT repair with primary ACLR were significantly improved, except for LME, at the 2-year postoperative follow-up. After repair of type II PLMRT injuries, the presence of sagittal LME was associated with increased PTS and ATSLC.

Level of Evidence

Level III, retrospective cohort study.

Association of Increased Lateral Femoral Condylar Ratio With Lateral Meniscus Posterior Root Tear in Noncontact ACL Injury

Background

In the setting of anterior cruciate ligament (ACL) injury, lateral meniscus posterior root tears (LMPRTs) are less readily diagnosed on preoperative magnetic resonance imaging (MRI). Therefore, to predict LMPRTs in ACL injuries, it is necessary to understand the risk factors associated with them.

Purpose/Hypothesis

The purpose of this study was to investigate the association of lateral femoral condylar ratio (LFCR) with LMPRTs in ACL injuries. It was hypothesized that an increased LFCR would be associated with LMPRTs in noncontact ACL injuries.

Study Design

Cohort study; Level of evidence, 3.

Methods

Enrolled were consecutive patients who underwent primary acute (<6 weeks from injury) ACL reconstruction after noncontact injury and had LMPRT confirmed on preoperative MRI and arthroscopically (combined group; n = 62) as well as patients who underwent isolated acute ACL reconstruction (isolated group; n = 80) who were matched to the combined group by age, height, and body mass index (BMI). All patients underwent surgery between January 1999 and November 2021. LFCR and posterior tibial slope (PTS) were measured and compared between the isolated and combined groups. The area under the receiver operating characteristic curve (AUC) was calculated to determine the cutoff for detecting increased risk of LMPRTs.

Results

The demographic characteristics of the 2 groups did not differ significantly, nor did the PTS. The LFCR was a significant factor (odds ratio [OR], 1.23; P = .001) associated with LMPRT. Patient age, height, BMI, and PTS were not associated with LMPRT. The AUC (0.66; 95% CI, 0.57-0.75) for LFCR had a sensitivity of 39% and specificity of 90% to predict LMPRT. The calculated cutoff associated with an increased risk for LMPRT when compared with the isolated group was 67.0% (OR, 4.98; 95% CI, 2.10-11.79).

Conclusion

Increased LFCR was associated with the presence of LMPRTs in patients with acute ACL injuries. The LFCR may provide surgeons with additional information regarding the risk of having a concomitant LMPRT when planning ACL reconstructions.

Biomechanical Comparison of the Simple Suture Technique, Meniscal Matrix-Assisted Repair, and a Novel Meniscus Cap Suture Technique for Complex Meniscal Repair

Background

Meniscal repair is the gold standard for simple morphology tears. However, when the morphology and chronicity of the tear are less favorable, the success of the standard techniques is reduced.

Purpose/Hypothesis

To compare meniscal repair augmented by a new bioresorbable implant (Meniscus Cap) versus a traditional simple suture technique and the currently available augmented repair collagen matrix meniscus wrapping technique. It was hypothesized that the Meniscus Cap suture technique would increase ultimate failure load and less displacement during cyclic loading.

Study Design

Controlled laboratory study.

Methods

A total of 80 fresh porcine menisci were harvested. Complex tears were created in 60 menisci, and 20 intact menisci were tested as the control group. Repairs were performed on the 60 meniscal tears using 1 of the 3 techniques (20 menisci each): an inside-out H-suture group (SS), the collagen matrix wrapping technique (CMW), and the Meniscus Cap bioresorbable implant group (CM). The menisci were subjected to 500 loading cycles from 4 to 20 N at a frequency of 1 Hz, and the total displacement was recorded. Then, the specimens underwent load to failure testing at a rate of 3.15 mm/s, and the failure mode was noted.

Results

After 500 cycles of cyclic loading, there were no significant differences in displacement between the controls and CM group (0.524 vs 0.448 mm; P = .95). The displacement after the CM was significantly smaller compared with the CMW and the SS (0.448 vs 1.077 mm [P = .0009] and 0.448 vs 0.848 mm [P = .04], respectively). The ultimate load to failure was significantly greater for the controls and the CM group compared with the SS and CMW groups (controls, 1278.7 N and CM, 628.5 N vs CMW, 380.1 N and SS, 345.1 N; P < .05). The failure mode was suture breakage (suture failure) for all repairs.

Conclusion

In a porcine specimen meniscal repair model, the biomechanical properties of a novel Meniscus Cap repair technique were superior to that of the simple suture and CMW techniques.

Clinical Relevance

The results suggest that the Meniscal Cap repair technique may provide sufficient primary stability of the meniscal fixation even in the cases of complex meniscal tears.

An All-Inside Repair Technique for Unstable Type-IV Lateral Meniscal Posterior Root Tear

Lateral meniscal posterior root tears are defined as tears of meniscus within 9 mm from the bony root attachment. Unrepaired root tears significantly compromise the biomechanical functions of the meniscus, resulting in early and accelerated osteoarthritis. Several authors have described various techniques to reattach the posterior root of the lateral meniscus, and decent short-term results have been observed. Although most previous techniques are capable of repairing radial root tears, difficulties are encountered when repairing oblique type IV tears. In this technique note, the author describes an efficient side-to-side repair technique using the FAST-FIX system, which is practical in repairing the type IV tears of the lateral meniscus. This technique includes certain sequence of the stitches and skills of controlling the root remnant, which makes it easy to penetrate the meniscus and to achieve anatomic repair.

Repairing Complete Radial Tears of the Lateral Meniscus: Arthroscopic All-Inside Double Vertical Cross-Suture Technique Is Effective and Safe With 2-Year Minimum Follow-Up

PURPOSE

To assess the failure rate and clinical outcomes of the all-inside, double-vertical, cross-suture technique in repairing complete radial tears of the lateral meniscus.

METHOD

We retrospectively reviewed records of patients with this injury on whom the present technique was employed at our institution between 2011 and 2018, with at least 24 months of follow-up. Six months postoperatively, the meniscus healing and extrusion status were evaluated through magnetic resonance imaging. Preoperative and postoperative knee function, measured through IKDC, Lysholm knee, and Tegner activity scale scores, were compared.

RESULTS

In total, 27 patients underwent the procedure. The preoperative mean (standard deviation) IKDC score, Lysholm knee score, and Tegner activity scale scores were 53.4 ± 5.3, 63.2 ± 9.3, and 4 ± .7, respectively. At the last follow-up (≥24 months postoperatively), these scores increased to 92.1 ± 2.6, 90.8 ± 4.2, and 6.1 ± 1.3, respectively (all P < .05). Complete healing of the meniscus was observed in 23 patients, and 4 patients had meniscus retear or nonhealing. The overall retear or nonhealing rate was 14.8%. Healing rates between those with isolated radial tears (87.5%) and those with combined anterior cruciate ligament rupture (84.2%; P = .826) were comparable. No difference was observed in the progression of coronal and sagittal meniscus extrusion (P = .133 and .797, respectively).

CONCLUSION

In patients with complete radial tears of the lateral meniscus, the arthroscopic all-inside double vertical cross-suture repair technique resulted in an 85.2% healing rate, improvements in functional outcomes and activity levels, and no identifiable progression of meniscus extrusion. The all-inside double vertical cross-suture technique is effective and safe for the repair of radial tears of the meniscus.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Editorial Commentary: Biologic Augmentation of Meniscus Repair Is Complex

In the setting of biological augmentation for meniscus repair, it is extremely important to evaluate all aspects, including effectiveness, costs, potential risks, benefits, and limitations. It seems that everything matters in healing: the aspirate source of the bioactive agents, cell content, presence of stem cells and their type, growth factors, cytokines, biomechanical scaffold, and the quality of the tissue. There are several differences among mesenchymal, adipose, and peripheral blood stem cells, with the cell origin affecting the differentiation potential towards bone, cartilage and ligament. Moreover, different aspirate sources and fibrin clots have different content in cells, growth factors, and cytokines. In this equation, it is not as simple as the more the better. Different doses of growth factors may have different effects in the different cell types. And as this was not complicated enough, synergistic phenomena between cells and between growth factors can play a huge role. Add to that the role of the biomechanical environment, the proper timing of the healing phases and the inherent patient characteristics. There is very, very much to learn, and finally, we acknowledge that not all menisci repairs can always heal.

Editorial Commentary: Medial and Lateral Meniscus Root Injuries Are Distinct, and Indications for Repair May Differ: Get Down to the Root of the Problem!

Medial and lateral root injuries are different clinical entities. Medial root injuries are of a degenerative nature and frequently are associated with obesity and varus deformity. Lateral root injuries, however, are more often of traumatic origin and usually associated with injuries to the anterior cruciate ligament. There is also a biomechanical difference between the 2 injuries. In the case of medial root injuries, the loss of circular hoop tension leads to an increase in peak contact pressure. In the case of lateral root lesions, the loss of hoop stress can be compensated for by an intact meniscofemoral ligament. Nevertheless, a repair also seems to make sense on the lateral meniscus, as the posterior root also has a stabilizing effect on the knee. The most suitable technique for lateral root repair depends on the type of lesion. A transtibial pull out repair is suitable for frequent avulsion injuries (type 1). In the case of type 2 injuries, which are also common, a side-to-side suture is an option.