Frequency of anterolateral ligament tears and ramp lesions in patients with anterior cruciate ligament tears and associated injuries indicative for these lesions-a retrospective MRI analysis

OBJECTIVES

To assess the frequency of anterolateral ligament (ALL) tears and ramp lesions (RL) detected with MRI in patients with anterior cruciate ligament (ACL) tears and to describe associated injuries indicative for these lesions.

METHODS

In this retrospective study, 164 patients with surgically verified ACL tears were included. Preoperative MRI scans were reviewed for ALL tears and different types of RL. All coexisting meniscal tears, tears of the medial (MCL) and lateral collateral band (LCL), and posterior-medial tibial bone marrow edema (BME) were recorded. The frequency of ALL tears and RL was assessed and coexisting injuries were correlated using Pearson's chi-square test. A p < 0.05 was defined as statistically significant. In cases of multiple testing, Bonferroni's correction was applied.

RESULTS

ALL tears and RL combined were detected in 28 patients (17.1%), ALL tears in 48 patients (29.3%), and RL in 54 patients (32.9%) which were significantly associated to each other. ALL tears were significantly associated with tears of the posterior horn of the lateral meniscus (PHLM), BME, and with tears of the LCL and MCL. RL were significantly associated with tears of the posterior horn of the medial (PHMM) and PHLM, with BME, and with tears of the LCL.

CONCLUSIONS

ACL tears are associated with RL or ALL tears in about one-third of cases and with both lesions combined in about one-fifth of cases. ALL tears and RL are significantly associated with additional posttraumatic injuries, which can thus be indicative of these lesions.

KEY POINTS

• ACL tears were associated with ramp lesions or ALL tears in about one-third of the cases. • Ramp lesions and ALL tears were significantly associated with each other, tear in the PHLM, tear in the LCL, and BME. • ALL tears were more frequently associated with instable classified ramp lesion type 4b and type 5.

End-to-end deep learning model for segmentation and severity staging of anterior cruciate ligament injuries from MRI

PURPOSE

The purpose of this study was to develop a semi-supervised segmentation and classification deep learning model for the diagnosis of anterior cruciate ligament (ACL) tears on MRI based on a semi-supervised framework, double-linear layers U-Net (DCLU-Net).

MATERIALS AND METHODS

A total of 297 participants who underwent of total of 303 MRI examination of the knee with fat-saturated proton density (PD) fast spin-echo (FSE) sequence in the sagittal plane were included. There were 214 men and 83 women, with a mean age of 37.46 ± 1.40 (standard deviation) years (range: 29-44 years). Of these, 107 participants had intact ACL (36%), 98 had partially torn ACL (33%), and 92 had fully ruptured ACL (31%). The DCLU-Net was combined with radiomic features for enhancing performances in the diagnosis of ACL tear. The different evaluation metrics for both classification (accuracy, sensitivity, accuracy) and segmentation (mean Dice similarity coefficient and root mean square error) were compared individually for each image class across the three phases of the model, with each value being compared to its respective value from the previous phase. Findings at arthroscopic knee surgery were used as the standard of reference.

RESULTS

With the addition of radiomic features, the final model yielded accuracies of 90% (95% CI: 83-92), 82% (95% CI: 73-86), and 92% (95% CI: 87-94) for classifying ACL as intact, partially torn and fully ruptured, respectively. The DCLU-Net achieved mean Dice similarity coefficient and root mean square error of 0.78 (95% CI: 0.71-0.80) and 0.05 (95% CI: 0.06-0.07), respectively, when segmenting the three ACL conditions with pseudo data (P < 0.001).

CONCLUSION

A dual-modules deep learning model with segmentation and classification capabilities was successfully developed. In addition, the use of semi-supervised techniques significantly reduced the amount of manual segmentation data without compromising performance.

High failure rate of anterior cruciate ligament reconstruction with bimeniscal repair: A case-control study

BACKGROUND

Bimeniscal lesions are common in patients with anterior cruciate ligament (ACL) tears. However, bimeniscal repair is rarely performed during ACL reconstruction.

OBJECTIVE

To assess outcomes after ACL reconstruction with bimeniscal repair.

HYPOTHESIS

Bimeniscal lesions, even when repaired, are associated with poorer outcomes of ACL reconstruction.

MATERIAL AND METHODS

A retrospective case-control design was used. The cases were 15 patients who underwent ACL reconstruction, without procedures on any other ligaments, combined with bimeniscal repair, between May 2009 and May 2013 (3.2% of all ACL reconstructions during the study period). This group (2-Mc group) was matched on age, gender, body mass index, and time to surgery to 30 patients who underwent ACL reconstruction and had no meniscal lesions (0-Mc group) and to 30 patients who underwent ACL reconstruction and repair of the medial meniscus (1-Mc group). After a mean follow-up of 3.6 years, clinical outcomes were assessed based on the KOOS, Lysholm, and IKDC scores and knee laxity based on TELOS and GNRB measurements. The primary outcome measure was the rate of ACL re-rupture. Secondary outcome measures were functional outcomes and rate of delayed meniscectomy.

RESULTS

The ACL re-rupture rate was significantly higher in the 2-Mc group than in the 0-Mc and 1-Mc groups pooled (20%, vs. 1.7%; P=0.02). The functional scores showed no significant differences across groups. Post-operative differential laxity was significantly greater in the 2-Mc group (3.3mm by TELOS, P=0.02; and 2.5mm by GNRB, P=0.03) than in the 0-Mc and 1-Mc groups pooled. Delayed meniscectomy was performed in none of the 2-Mc group patients and in 2 of the 1-Mc group patients.

CONCLUSION

ACL reconstruction combined with bimeniscal repair is a rarely performed procedure. It is associated with a high ACL re-rupture rate and greater differential laxity. Meniscal outcomes of bimeniscal repair, in contrast, are good.

LEVEL OF EVIDENCE

III, matched case-control study.