Smaller meniscal width and greater severity of meniscal extrusion correlated with knee joint degeneration. An anterocentral shift on preoperative MRI was a risk factor for degenerative changes and smaller residual meniscal width.

III.

These results indicate the potential for ACL reconstruction with regenerated direct insertion morphology.

Retrospective comparative study, Level III.

Background: Although the sensitivity and specificity of magnetic resonance imaging (MRI) for the diagnosis of primary meniscal tears are high, these values are lower for the assessment of healing status of repaired menisci. Purpose: To compare the accuracy of MRI T2 mapping and conventional MRI in assessing meniscal healing after repair. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Patients who underwent meniscal repair with concurrent anterior cruciate ligament reconstruction between 2012 and 2016 and had a follow-up second-look arthroscopy were enrolled. The patients were divided into healed and incompletely/not healed groups based on the second-look arthroscopy findings. For the repaired menisci, the following were compared between the groups, (1) Stoller and Crues classification on conventional MRI with a proton density-weighted fat-saturated sequence and (2) the remaining colored meniscal tear line on T2 mapping coincident with the high signal line showing the primary tear on conventional MRI were compared. The change of T2 relaxation time (ΔT2) of the colored meniscal tear line pre- to postoperatively was compared between the groups. The mean T2 relaxation time of the whole area of the postoperative meniscus at each slice was also compared with that of control menisci to assess the whole quality of the repaired meniscus. Results: A total of 26 menisci from 24 knees were assessed (16 healed menisci, 10 incompletely/not healed menisci). According to the Crues classification on conventional MRI, 8 of 16 healed menisci and 3 of 10 incompletely/not healed menisci improved from grade 3 to 2, with there being no significant difference between the groups ( P = .43). However, the colored meniscal tear line remained in only 3 of the 16 healed menisci as compared with 9 of the 10 incompletely/not healed menisci, and the presence of this colored line allowed differentiation between healed menisci and incompletely/not healed menisci (sensitivity, 81.3%; specificity, 90.0%; odds ratio, 39.0; P = .001). The mean (SD) ΔT2 was −31.1 ± 3.2 and −19.9 ± 4.4 ms in the healed and incompletely/not healed groups, respectively ( P < .001). Receiver operating characteristic curve analysis showed a cutoff ΔT2 value of −22.3 ms for separation of meniscal healing ( P < .001). The T2 relaxation times of the whole area of the repaired menisci were 31.7 ± 3.4 and 32.8 ± 3.8 ms in the healed and incompletely/unhealed groups, respectively ( P = .69), with these values being significantly longer than the 26.9 ± 2.2 ms in the controls ( P < .001). Conclusion: MRI T2 mapping allowed the differentiation of healing status after meniscal repair, with high sensitivity and specificity as compared with conventional MRI.

Introduction The purpose of this study was to assess the direct injection of bone marrow-derived mesenchymal stem cells (BMSCs) suspended in hyaluronic acid (HA) combined with drilling as a treatment for chondral defects in a canine model. Methods Tibial bone marrow was aspirated, and BMSCs were isolated and cultured. One 8.0-mm diameter chondral defect was created in the femoral groove, and nine 0.9-mm diameter holes were drilled into the defect. BMSCs (2.14 × 10 7 cells) suspended in HA were injected into the defect. HA alone was injected into a similar defect on the contralateral knee as a control. Animals were sacrificed at 3 and 6 months. Results Although the percentage of coverage assessed macroscopically was significantly better at 6 months than at 3 months in both the BMSC (p = 0.02) and control (p = 0.001) groups, there were no significant differences in the International Cartilage Repair Society grades. The Wakitani histological score was significantly better at 6 months than at 3 months in the BMSC and control groups. While the control defects were mostly filled with fibrocartilage, several of the defects in the BMSC group contained hyaline-like cartilage. The mean Wakitani scores of the BMSC group improved from 7.0 ± 1.0 at 3 months to 4.6 ± 0.9 at 6 months, and those of the control group improved from 9.4 ± 1.2 to 6.0 ± 0.6. The BMSC group showed significantly better regeneration than the control group at 3 months (p = 0.04), but the difference at 6 months was not significant (p = 0.06). Conclusions The direct injection of BMSCs in HA combined with drilling enhanced cartilage regeneration.

Purpose The purpose of this study was to compare femoral graft bending angle between patients with femoral tunnel reamed at less than 80° of knee flexion and those with 80° and above in anatomical anterior cruciate ligament (ACL) reconstruction using modified transtibial technique. Methods Forty-eight patients who underwent ACL reconstruction using bone-patellar-tendon-bone autograft in modified transtibial technique and CT scan at 1 week postoperatively were included in this study. A femoral guidewire insertion into aimed femoral position at the medial wall of the femoral lateral condyle was started at about 75° of knee flexion. When the tip of the guidewire was blown out into femoral posterior wall, the guidewire was inserted again after increasing knee flexion angle. Distance from femoral tunnel exit on the femoral lateral cortex-femoral posterior cortex (Distance-E) was measured on postoperative lateral radiograph. Femoral and tibial tunnel position was measured on 3-D CT images. In addition, femoral graft bending angle was measured on reconstructed 2-D CT images. Patients were divided into two groups depending on whether femoral tunnel was created at less than 80° of knee flexion (group A) or 80° or more (group B). Results There were 32 patients in group A and 16 patients in group B, respectively. Average knee flexion angle was 77.2° [standard deviation (SD) 1.6] in group A and 83.6° (SD 2.4) in group B, respectively (p < 0.05). Average Distance-E was 5.1 mm (SD 2.6) in group A and 6.6 mm (SD 3.8) in group B, respectively. There was no significant difference in the femoral and tibial tunnel position between group A and B. Femoral graft bending angle was significantly smaller in group A [average angle: 50.9° (SD 6.6)] than in group B [average angle: 55.0° (SD 6.6)] (p < 0.05). Conclusions Anatomical femoral tunnel was able to be created at less than 80° of knee flexion in two-thirds of patients. Shallower flexion angle (less than 80°) provided gentler femoral graft bending angle compared to 80° or more of knee flexion. Therefore, femoral tunnel creation in modified transtibial technique should be started at between 75° and 80° of knee flexion to reduce femoral graft bending angle. Shallow knee flexion angle during femoral tunnel creation using modified transtibial technique can reduce femoral graft bending angle and may lead to better clinical outcomes in ACL reconstruction. Levels of evidence Retrospective comparative study, Level III.

Background: Few studies have attempted to identify risk factors associated with irreparable meniscal tears at anterior cruciate ligament reconstruction (ACLR) and to describe follow-up data, such as the failure rate, after meniscal repair. Purpose: To investigate the associations of age, sex, body mass index (BMI), time to surgery (TTS), and preinjury Tegner score with the presence of meniscal injuries and irreparable meniscal tears at primary ACLR. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A retrospective review was performed on 784 patients who underwent primary ACLR by a single surgeon between 2005 and 2017 (406 men and 378 women; mean age, 25.8 years; mean BMI, 23.1; median TTS, 3 months; median preinjury Tegner score, 7). All patients had a minimum follow-up of 12 months (mean postoperative follow-up, 33.0 months). Multivariate logistic regression analysis was conducted to determine the association of patient variables with the presence of meniscal injuries and irreparable meniscal tears during primary ACLR. Results: The risk factor for medial meniscal injuries was TTS ≥3 months (odds ratio [OR], 4.213; 95% CI, 3.104-5.719; P < .001). The presence of irreparable medial meniscal tears increased with older age (OR, 1.053; 95% CI, 1.024-1.084; P < .001), higher BMI (OR, 1.077; 95% CI, 1.003-1.156; P = .042), and TTS ≥3 months (OR, 1.794; 95% CI, 1.046-3.078; P = .034). On multivariate analysis, none of the variables were significantly associated with lateral meniscal injuries and irreparable meniscal tears. The failure rate, defined as patients who needed additional medial meniscal surgery after medial meniscal repair, was 4.6%. Conclusion: Time from ACL injury to reconstruction of ≥3 months was strongly associated with medial meniscal injuries and irreparable medial meniscal tears at primary ACLR. Older age and increased BMI were also risk factors for the presence of irreparable medial meniscal tears at ACLR.