3D-MRI combined with signal-to-noise ratio measurement can improve the diagnostic accuracy and sensitivity in evaluating meniscal healing status after meniscal repair

Do MRI Results Represent Functional Outcomes Following Arthroscopic Repair of an Isolated Meniscus Tear in Young Patients?-A Prospective Comparative Cohort Study

BACKGROUND

The use of postoperative MRI to assess the healing status of repaired menisci is a long-standing issue. This study evaluates and compares functional and MRI outcomes following an arthroscopic meniscus repair procedure with the aim of postoperative MRI diagnostic accuracy clarification in young patients.

METHODS

A total of 35 patients under 18 years old who underwent isolated meniscus repair were included. The Pedi-IKDC score, Lysholm score, and Tegner activity index (TAS) were compared between the groups formed according to the Stroller and Crues three-grade classification of postoperative MRI-based evaluations. Grade 3 MRI views were classified as unhealed, grade 2 as partially healed, and grade 1 as fully healed within the repaired meniscus, whereas grade 3 cases were considered unsuccessful due to MRI evaluation.

RESULTS

MRI assessment revealed 4 cases of grade 1 (11.4%), 14 cases of grade 2 (40.8%), and 17 cases of grade 3 (48.0%) lesions. Pedi-IKDC and TAS scores were significantly higher among MRI grade 2 patients than among MRI grade 3 patients (p < 0.05). Weak negative correlations between MRI grades and all functional scales were found (p < 0.05). ROC analysis showed that Pedi-IKDC and TAS scores could correctly classify 77% and 71% of MRI grade 3 patients, respectively. The optimal cut-off values to detect grade 3 patients were 88.74 for the Pedi-IKDC score and 4.5 for the TAS score.

CONCLUSIONS

To conclude, established functional score cut-off values may help identify unhealed meniscus repair patients.

Association Between MRI Signal Intensity of the Repaired Lateral Meniscus and Residual Anterolateral Knee Laxity After ACL Reconstruction

Background

Anterolateral knee laxity (ALLx) has been linked to tears of the lateral meniscus (LM) and anterior cruciate ligament (ACL) injury.

Purpose

To investigate the longitudinal relationship between the signal intensity (SI) of the repaired LM on magnetic resonance imaging (MRI) and residual ALLx after ACL reconstruction (ACLR).

Study Design

Cohort study; Level of evidence, 3.

Methods

Included were 87 patients who underwent double-bundle ACLR and lateral meniscal repair (mean age, 23.5 years; body mass index, 23.7 kg/m2; 56 women) at a single institution between 2010 and 2019. Proton density-weighted (PDW) and T2-weighted (T2W) MRI was performed at 3, 6, and 12 months postoperatively, and the SI ratio (SIR) was calculated as (SI of the repaired LM)/(SI of the posterior cruciate ligament). At the 12-month follow-up, ALLx was evaluated using the pivot-shift test; an International Knee Documentation Committee grade ≥1 indicated residual ALLx.

Results

Overall, 12 patients (13.8%) exhibited ALLx at 12 months postoperatively. At 3 months postoperatively, the SIR on PDW images (SIR-PDW) was significantly higher in patients with ALLx versus those without ALLx (1.98 ± 0.77 vs 1.49 ± 0.52, respectively; P = .007); there was no difference in the SIR on T2W images between the groups. SIR-PDW at 3 months postoperatively was correlated negatively with patient age (r = -0.308, P = .004). When patients were stratified into a younger (≤22 years; n = 53; ALLx = 7 [13.2%]) and an older (>22 years; n = 34; ALLx = 5 [14.7%]) group, the area under the receiver operating characteristic curves (AUCs) for SIR-PDW in the younger group were statistically significant for predicting the prevalence of ALLx at all follow-up times (AUCs, 0.733-0.788) with optimal cutoff values of 2.00 at 3 months, 1.50 at 6 months, and 1.50 at 12 months. Logistic regression analysis revealed that if younger patients consistently had higher SIR-PDW values than the cutoff values, they were more likely to have residual ALLx (odds ratios, 10.24-23.57).

Conclusion

For younger patients who underwent both ACLR and lateral meniscal repair, higher MRI SI of the repaired LM was associated with a higher prevalence of residual ALLx.

MRI Criteria for Healing at 1 Year After Repair of a Traumatic Meniscal Tear

BACKGROUND

Meniscal repair for a traumatic meniscal tear is increasingly used to preserve the meniscus. Interpreting postoperative magnetic resonance imaging (MRI) scans remains challenging, especially in symptomatic patients. There is a lack of reliable MRI criteria to affirm the healed character of a traumatic meniscal injury repair.

PURPOSE

To identify relevant MRI criteria for meniscal healing after meniscal repair.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We prospectively included all patients with a traumatic meniscal injury who underwent either an isolated meniscal repair or a repair during a concomitant anterior cruciate ligament reconstruction. A standardized preoperative and postoperative clinical evaluation was performed, along with collection of functional scores-Knee injury and Osteoarthritis Outcome Score, International Knee Documentation Committee, Lysholm Score, and 36-Item Short Form Health Survey. An MRI scan was performed 1 year postoperatively and compared with the preoperative MRI scan. The following MRI aspects were analyzed: variation of morphology and fat-saturated (FS) T2 intensity signal and pre- and postoperative tear diastasis measurement.

RESULTS

Fifty patients (age, mean ± SD, 28.7 ± 8.5 years [range, 16-45 years]) who were 1 year postoperative were included. All patients were considered clinically healed had the same MRI characteristics. A signal change (FS T2) was observed from a high signal intensity fluid to a nonfluid moderate signal intensity. The morphology of the lesion was more complex: from the initial lesion, line ramifications appeared, creating the appearance of tree branches. The tear diastasis decreased (from 2.3 ± 0.5 mm [range, 1.3-3.5] to 1.1 ± 0.28 mm [range, 0.5-1.5]).

CONCLUSION

MRI criteria confirming meniscal healing after traumatic meniscal repair at 1 year were identified: a change in the intrameniscal signal becoming nonfluid and moderate in intensity; a reduction in tear diastasis to <1.5 mm; and a change in the signal morphology of the repaired meniscus.

Clinical and MRI Outcomes of Repaired Peripheral Longitudinal Tears of the Posterior Horn of the Medial Meniscus With ACL Reconstruction: Results According to Tear Size

Background

Arthroscopic repair of longitudinal tears in the medial meniscal posterior horn (MMPH) has been reported to result in high rates of meniscal healing when performed alongside anterior cruciate ligament reconstruction (ACLR). However, studies that have focused on longitudinal tears and their impact on clinical outcomes after arthroscopic repair are insufficient.

Purpose

To investigate the clinical outcome and healing status after concomitant arthroscopic ACLR and repair of MMPH peripheral longitudinal tears, with respect to the tear length.

Study Design

Cohort study; Level of evidence, 3.

Methods

A total of 263 patients who underwent concurrent arthroscopic suture repair of longitudinal tears of the MMPH and ACLR were enrolled. All patients had 2-year postoperative magnetic resonance imaging (MRI) evaluations, and 61% of patients underwent a second-look arthroscopy. The exclusion criteria were partial meniscectomies and multiligament injuries. Patients were assessed pre- and postoperatively for clinical scores, amount of anterior translation, grade of pivot shift, and presence of meniscal tear extension. According to the length of longitudinal tears, patients were classified into 2 groups: (1) patients with tears that were located in the posterior compartment and (2) patients with tears that extended to the midbody of the meniscus. Binary stepwise logistic regression analysis was used to evaluate the risk factors for unhealed menisci as identified by MRI.

Results

A total of 83 patients were included in this study-52 patients (group 1) had MMPH tears without tear extension and 31 patients (group 2) had MMPH tears with tear extension. There were no differences in outcomes between the groups, including the healing rate after meniscal repair (P > .05). Based on postoperative MRI scans, 67 patients (80.7%) were categorized as completely healed and 16 patients (19.3%) as unhealed. There were no significant differences between the completely healed and unhealed groups in outcomes or the rate of preoperative midbody tear extension. Higher body mass index and lower preoperative Lysholm scores were identified as risk factors for unhealed menisci.

Conclusion

Overall, the rate of complete healing of MMPH tears repaired concomitantly with ACLR was 80.7% (67/83), and midbody tear extension did not affect the healing rate of the repaired meniscus. Results indicate that suture repair for unstable MMPH tears should be considered regardless of tear size.

Second-Look Arthroscopic Evaluation of Healing Rates After Arthroscopic Repair of Meniscal Tears: A Systematic Review and Meta-analysis

Background:

Evaluation of meniscal healing status after repair is important, as it allows the surgeon to inform patients whether they can increase their activities or return to sports.

Purpose:

To identify the healing rates after arthroscopic repair of meniscal tears via second-look arthroscopic evaluation.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

Searches of PubMed, Embase, Scopus, and the Cochrane databases were conducted to identify relevant studies published before June 1, 2020. Studies were eligible for this meta-analysis if they provided data regarding healing status of the meniscus at second-look arthroscopy. Random-effects meta-analyses were generated to provide pooled meniscal healing estimates. We further performed subgroup analysis to investigate the healing rates of the meniscus under different situations.

Results:

A total of 41 studies with 1908 individuals were included in the study. The pooled analysis showed the complete healing rate was 74% (95% confidence interval [CI], 67%-80%), the partial healing rate was 10% (95% CI, 6%-16%), and the failure rate was 12% (95% CI, 10%-15%) for arthroscopic repair of meniscal tears via second-look arthroscopic evaluation. Sensitivity analysis demonstrated that no individual study affected the overall healing rate by >1%. Subgroup analysis found higher meniscal healing rates in patients with the following characteristics: age <40 years, male, body mass index <26, red-red tear location, tear in posterior horn, vertical tear, outside-in technique, repair concomitant with anterior cruciate ligament reconstruction, weight-restricted rehabilitation, and time interval from meniscal repair to second-look arthroscopy >12 months.

Conclusion:

In this systematic review, the complete healing rate was 74%, the partial healing rate was 10%, and the failure rate was 12% for arthroscopic repair of meniscal tears via second-look arthroscopic evaluation.

Vibration Stimulation as a Non-Invasive Approach to Monitor the Severity of Meniscus Tears

Musculoskeletal disorders and injuries are one of the most prevalent medical conditions across age groups. Due to a high load-bearing function, the knee is particularly susceptible to injuries such as meniscus tears. Imaging techniques are commonly used to assess meniscus injuries, though this approach suffers from limitations including high cost, need for skilled personnel, and confinement to laboratory or clinical settings. Vibration-based structural monitoring methods in the form of acoustic emission analysis and vibration stimulation have the potential to address the limits associated with current diagnostic technologies. In this study, an active vibration measurement technique is employed to investigate the presence and severity of meniscus tear in cadaver limbs. In a highly controlled ex vivo experimental design, a series of cadaver knees (n =6) were evaluated under an external vibration, and the frequency response of the joint was analyzed to differentiate the intact and affected samples. Four stages of knee integrity were considered: baseline, sham surgery, meniscus tear, and meniscectomy. Analyzing the frequency response of injured legs showed significant changes compared to the baseline and sham stages at selected frequency bandwidths. Furthermore, a qualitative analytical model of the knee was developed based on the Euler-Bernoulli beam theory representing the meniscus tear as a change in the local stiffness of the system. Similar trends in frequency response modulation were observed in the experimental results and analytical model. These findings serve as a foundation for further development of wearable devices for detection and grading of meniscus tear and for improving our understanding of the physiological effects of injuries on the vibration characteristics of the knee. Such systems can also aid in quantifying rehabilitation progress following reconstructive surgery and / or during physical therapy.