A larger side-to-side difference in anterior knee laxity increases the prevalence of medial and lateral meniscal injuries in patients with ACL injuries

The stability of repaired meniscal root can affect postoperative cartilage status following medial meniscus posterior root repair

BACKGROUND

Transtibial pullout repair yields beneficial clinical outcomes in patients with medial meniscus (MM) posterior root tear. However, the relationship between repaired meniscal root healing status and postoperative clinical outcomes remains unclear. We aimed to evaluate changes in articular cartilage damage and clinical scores after pullout repair using two simple stitches (TSS).

METHODS

Thirty-three patients who underwent pullout repair using TSS were assessed. Healing status was assessed by a semi-quantitative second-look arthroscopic scoring system comprising three evaluation criteria (width of bridging tissues, stability of the repaired root, and synovial coverage), 1 year postoperatively. MM medial extrusion (MMME) and cartilage damage were assessed preoperatively and 1 year postoperatively. The medial compartment was divided into 8 zones (A-H) for comparison of preoperative and 1-year postoperative cartilage damage. Clinical outcomes were evaluated using the Knee Injury and Osteoarthritis Outcome score, Lysholm score, International Knee Documentation Committee scores, and visual analogue scale pain score.

RESULTS

Although cartilage damage did not aggravate significantly in most medial compartment areas, MMME progressed at 1 year postoperatively. No statistical differences were observed in cartilage damage between the central-to-medial area of the medial femoral condyle and the medial tibial plateau area at 1 year postoperatively. Regarding semi-quantitative healing scores, the stability score was significantly correlated with the International Cartilage Repair Society grade at 1 year postoperatively. All 1-year and 2-year clinical scores significantly improved compared with the preoperative scores.

CONCLUSION

Regarding TSS repair, stability of repaired meniscal root negatively correlated with cartilage damage in the medial compartment loading area. All 1-year and 2-year clinical scores significantly improved than those of the preoperative scores. Achieving MM stability is crucial for suppressing cartilage degeneration.

LEVEL OF EVIDENCE

IV case series study.

High-Precision Wearable Displacement Sensing System for Clinical Diagnosis of Anterior Cruciate Ligament Tears

An anterior cruciate ligament (ACL) tear is a common musculoskeletal injury with a high incidence. Traditional diagnosis employs magnetic response imaging (MRI), physical testing, or other clinical examination, which relies on complex and expensive medical instruments, or individual doctoral experience. Herein, we propose a wearable displacement sensing system based on a grating-structured triboelectric stretch sensor to diagnose the ACL injuries. The stretch sensor exhibits a high resolution (0.2 mm) and outstanding robustness (over 1,000,000 continuous operation cycles). This system is employed in clinical trial to diagnose ACL injuries. It measures the displacement difference between the affected leg and the healthy leg during Lachman test. And when such a difference is greater than 3 mm, the ACL is considered to be at risk for injury or tear. Compared with the gold standard of arthroscopy, the consistency rate of this wearable diagnostic system reached about 85.7%, which is higher than that of the Kneelax3 arthrometer (78.6%) with a large volume. This shows that the wearable system possesses the feasibility to supplement and improve existing arthrometers for facile diagnosing ACL injuries. It may take a promising step for wearable healthcare.

A novel digital arthrometer to measure anterior tibial translation

BACKGROUND

Measurement of knee laxity after anterior cruciate ligament (ACL) injury is crucial for appropriate treatment and rehabilitation decision-making. This study examined the potential of a new digital arthrometer (Ligs, Innomotion, Shanghai, China) to quantify anterior tibial translation (ATT) in patients with ACL injuries and in healthy subjects.

METHODS

A total of 60 participants included 30 subjects with single-leg ACL injuries and 30 healthy subjects included as controls. The lower leg was immobilized. The thruster is positioned posterior to the lower leg and parallel to the tibial tuberosity in the sagittal plane. The load is applied vertically to the tibia under a dynamic load of 0-150 N, with continuous displacement recorded. The intrarater and interrater reliability will be examined. ATT and side-to-side differences (SSD) between the control and ACL injury groups were compared. Receiver operating characteristic (ROC) curves were analyzed, and the area under the curve (AUC) was calculated to determine the diagnostic accuracy of the Ligs.

RESULTS

The interrater ICC was 0.909 and the intrarater ICC was 0.943. Significant differences in the SSD were observed between the control and ACL injury groups (for all P < 0.05), with the largest effect size (ES = 1.12) at 80 N. When comparing ATT at different loads between injured and healthy sides in the ACL injury group, displacement was statistically significant at different loads. At a load of 150 N, the AUC was the maximum (0.857) and the sensitivity and specificity were 0.87 and 0.73, respectively.

CONCLUSIONS

A digital arthrometer can be used as a quantitative instrument to quantify knee laxity. Quantitative measurement of ATT and SSD under controlled loading can be an objective and effective tool for clinical practice.

Incidence and type of meniscal tears in multilligament injured knees

PURPOSE

Meniscal injuries occurring during multi-ligament knee injuries (MLKI) are underreported. The purpose of this study was to compare the incidence and type of meniscal tears seen at the time of multi-ligament reconstruction surgery compared to those occurring during isolated anterior cruciate ligament (ACL) surgery.

METHODS

Patients undergoing surgical treatment for MLKI and ACL-only injuries between 2010 and 2020 were reviewed. Two-hundred and thirty-five patients were included in the MLKI group. There were 131 chronic injuries and 104 acute injuries. Two-hundred and twenty-two ACL-only chronic injuries were used as a control group for comparison with the chronic MLKI group. Demographic data, type of meniscal tears, ligament injury patterns (Schenck classification) and time from injury to surgery were recorded. A delayed procedure was defined by a 4-week interval after the knee injury.

RESULTS

A meniscus was torn in 69 knees (29.4%): 36 knees (15.3%) with an isolated medial meniscus tear, 33 knees (17.9%) with an isolated lateral meniscus tear,.Nine knees (3.8%) had both menisci torn. MLKI with medial or lateral-sided bicruciate ligament injuries (KDIIIM-KDIIIL) were significantly associated with a lower rate of meniscal tears than knee injuries involving the ACL-only and medial/lateral-sided ligament injuries (KDI) (medial-sided injuries p = 0.025; lateral-sided injuries p = 0.049). Lateral-sided injuries had significantly less meniscal damage than medial-sided injuries: 22/124 (17.7%) vs. 41/100 (41%); (p < 0.001). No significant differences were found for frequency, type and distribution of meniscal tears between acute and chronic MLKI surgery. ACL-only chronic injuries were associated with a higher rate of meniscal tears: 123/222 knees (55.4%) vs. 35/131 (26.9%) chronic MLKI; (p < 0.001), mainly involving the medial meniscus: 102/222 (46%) vs. 18/131 (13.7%); (p < 0.001).

CONCLUSIONS

Meniscal tears were less common in the MLKI group than in the isolated ACL injury group. The degree of ligament injury patterns and the side of the injured collateral ligament influenced the type and incidence of meniscal damage. Contrary to isolated ACL injuries, a delayed procedure was not associated with a higher rate of meniscal lesions but did influence the type of treatment. Understanding of meniscal tears patterns in MLKI helps to improve the treatment management of these complex injuries.

High-grade pivot-shift phenomenon after anterior cruciate ligament injury is associated with asymmetry of lateral and medial compartment anterior tibial translation and lateral meniscus posterior horn tears

PURPOSE

To investigate whether the high-grade pivot-shift phenomenon is associated with asymmetry of the lateral and medial compartment anterior tibial translation (L-ATT and M-ATT) and lateral meniscus posterior horn (LMPH) tears in anterior cruciate ligament (ACL) injuries.

METHODS

A retrospective analysis was performed on 192 consecutive patients who had complete ACL injuries between January 2019 and December 2020. Among these, 156 met the inclusion criteria. L-ATT and M-ATT were measured using preoperative weight-bearing magnetic resonance imaging (MRI), and the differences between L-ATT and M-ATT were calculated. Thirty-five patients who demonstrated excessive differences in L-ATT and M-ATT (> 6.0 mm) were regarded as asymmetric (study group), and 36 patients with minimal or no differences in L-ATT and M-ATT (< 3.0 mm) were allocated to the control group. Demographic data, grade of the pivot-shift test, integrality of LMPH, and medial meniscus posterior horn (MMPH) were compared between the groups. Moreover, predictors of high-grade pivot-shift phenomenon, including asymmetry of L-ATT and M-ATT, integrity of LMPH and MMPH, time from injury to surgery, sex, age, and body mass index (BMI) were assessed using multivariable logistic regression analysis.

RESULTS

The difference between L-ATT and M-ATT in the study group was significantly higher than that in the control group (mean ± SD: 8.4 ± 2.1 mm vs. 1.5 ± 1.0 mm, P < 0.001). A higher proportion of patients with high-grade pivot-shift phenomenon (2 + and 3 +) and LMPH tears were identified in the study group (high-grade pivot-shift phenomenon: 25/35 vs. 13/36, P = 0.003; LMPH tears: 18/35 vs. 5/36, P = 0.001). Additionally, asymmetry of L-ATT, M-ATT (odds ratio 5.8; 95% CI 1.7-19.8; P = 0.005), and LMPH tears (odds ratio 3.8; 95% CI 1.3-11.6; P = 0.018) were found to be good predictors of the high-grade pivot-shift phenomenon after ACL injury, whereas MMPH tears, time from injury to surgery, sex, age, and BMI were not.

CONCLUSION

In patients with ACL injury, the high-grade pivot-shift phenomenon is associated with asymmetry between L-ATT and M-ATT, and LMPH tears.

LEVEL OF EVIDENCE

III.