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Background: Detection of meniscal ramp lesions concomitant with anterior cruciate ligament (ACL) injury using conventional magnetic resonance imaging (MRI) has low sensitivity, and these lesions are currently difficult to diagnose preoperatively., Purpose/hypothesis: The purpose of this study was to assess the accuracy of MRI in detecting the presence of meniscal ramp lesions in the 120° flexed-knee position compared with that in the near-extended-knee position. It was hypothesized that the diagnostic performance of MRI in the 120° flexed-knee position would be better than that in the extended-knee position., Study Design: Cohort study (Diagnosis); Level of evidence, 2., Methods: This retrospective study of prospectively collected data between February 2019 and January 2024 included 154 consecutive patients undergoing ACL reconstruction. All patients underwent 3-T MRI examination in the near extended- and 120° flexed-knee positions preoperatively. The presence and Thaunat classification of ramp lesions were separately detected on each MRI scan and confirmed via arthroscopy during ACL reconstruction. Diagnostic sensitivity, specificity, and conditional relative odds ratios for detecting ramp lesions and the classification accuracy were compared between 2 MRI modalities. The accuracies of these MRI scans in acute and chronic cases were also evaluated., Results: This study included 154 patients (79 male and 75 female; mean age, 29.0 ± 14.2 years). A total of 62 ramp lesions (40.3%) were observed on arthroscopy. The sensitivity and specificity of MRI in near extension were 69.4% and 77.2%, respectively, and those in flexion were 91.9% and 94.6%, respectively, with significant superiority in MRI at knee flexion ( P = .003 and P < .001, respectively). The conditional relative odds ratio between the MRI examinations at these 2 positions was 10.3 (95% CI, 4.82-21.8). The classification accuracy of MRI in flexion was significantly higher than that of MRI in near extension (accuracy, 49 vs 11; P < .001). The diagnostic accuracy of MRI in the 120° flexed-knee position was significantly higher than that in the near-extended-knee position in the acute cases ( P < .05); however, no significant differences were observed in the chronic cases., Conclusion: The diagnostic accuracy of MRI in the 120° flexed-knee position for detecting and classifying meniscal ramp lesions was superior to that of MRI in the near-extended-knee position., Competing Interests: The authors declared that they have no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Purpose: To confirm whether posterior displacement of the detached meniscocapsular structure in ramp lesions could be observed on magnetic resonance imaging (MRI) in the flexed knee position and to clarify whether this displacement on MRI is related to greater anterior knee laxity., Methods: This retrospective comparative trial study included 50 patients with anterior cruciate ligament injuries in whom attendant ramp lesions were observed on preoperative MRI. All patients underwent 3-T MRI at 120° of knee flexion preoperatively. The gap distance of the ramp lesion on sagittal slices was measured, and a distance greater than 1 mm was classified as gap positive. Additionally, joint effusion in the posteromedial recess was quantitatively evaluated by measuring the surface area of joint fluid. Prior to surgery, the side-to-side difference in anterior tibial translation (ATT) on stress radiographs at 20° of knee flexion was measured to evaluate anterior knee laxity. During anterior cruciate ligament reconstruction, the length of the ramp lesion was measured by a scale from the posteromedial portal., Results: Of the 50 knees, 29 had ramp lesion gaps greater than 1 mm on MRI at knee flexion. The gap-positive group had a significantly greater side-to-side difference in ATT (9.6 ± 3.6 mm vs 5.0 ± 2.7 mm, P < .001) and significantly larger ramp lesion length (15.7 ± 4.9 mm vs 11.7 ± 3.9 mm, P = .002) than the gap-negative group. The gap-positive group also had a significantly greater amount of joint effusion than the gap-negative group (P < .001)., Conclusions: Posterior displacement of the detached meniscocapsular structure in ramp lesions can be observed on MRI at knee flexion and is related to greater anterior knee laxity, lesion size, and joint effusion., Level of Evidence: Level III, retrospective comparative trial., (Copyright © 2023 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate whether the sagittal inclination angle (SIA) of a graft is associated with postoperative knee stability after anatomic anterior cruciate ligament (ACL) reconstruction., Methods: All patients who had undergone anatomic ACL reconstruction between April 2014 and September 2015 in addition to volunteers with no history of knee injury were eligible for inclusion in this study. The patients were evaluated by magnetic resonance imaging of the knee in full extension at 1 year after surgery, as were volunteers. The posterior tibial slope (PTS) angle and the SIA of the intact ACL and reconstructed graft were measured relative to each medial and lateral tibial plateau. The patients were examined for knee stability by the side-to-side difference in the anterior tibial translation on stress radiographs at minimum 2-year follow-up., Results: We included 43 patients (26 male, 17 female, mean age 32.8 ± 14.8 years) and 12 volunteers (7 male, 5 female, mean age 28.7 ± 3.1 years) as normal controls. The mean follow-up duration was 29.8 ± 3.6 months. The mean PTS angle and mean SIA in the patients did not significantly differ from those of the intact ACL. The PTS angle in the patients was not significantly correlated with postoperative side-to-side difference in the anterior tibial translation. However, the graft SIA was significantly correlated with the postoperative anterior tibial translation (medial SIA; r = 0.42, P = .005, lateral SIA; r = 0.52, P < .001)., Conclusions: Even if anatomically reconstructed, the graft SIA in reference to the tibial plateau at full knee extension is variable and is associated with postoperative knee stability. The larger graft SIA was correlated with graft laxity after anatomic ACL reconstruction., Level of Evidence: Level III, retrospective comparative study., (Copyright © 2021 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Purpose: To prospectively evaluate the sensitivity and specificity of magnetic resonance imaging (MRI) for diagnosing ramp lesions, to compare them between 1.5- and 3-T MRI, and to evaluate whether bone contusion of the posterior lip of the medial tibial plateau was associated with ramp lesions., Methods: For 155 knees that underwent primary ACL reconstruction, we prospectively examined for ramp lesions and medial meniscal body tears on MRI. MRI diagnosis of ramp lesions required high signal irregularity of the capsular margin or separation in the meniscocapsular junction of the medial meniscus posterior horn on sagittal images. Bone contusion of the posterior lip of the medial tibial plateau was verified in 105 knees with MRI performed within 6 weeks after injury. All ramp lesions were identified by transcondylar observation during surgery. The sensitivity and specificity of MRI for ramp lesions and body tears were measured. Furthermore, we evaluated whether bone contusion of the medial tibial plateau was associated with ramp lesions. The χ-square test was used for statistical analysis., Results: During surgery, ramp lesions were observed in 46 knees and medial meniscal body tears were seen in 35 knees. The sensitivity of MRI for ramp lesions was 71.7% and specificity was 90.5%. The sensitivity for ramp lesions was significantly lower than that for meniscal body tears (94.3%) (P = .01). The sensitivity of 3-T MRI (83.3%) was superior to that of 1.5-T MRI (67.6%), but not significantly different. The incidence of bone contusions was not significantly different among ramp lesions (38.5%), body tears (40.0%), or no tears (30.5%)., Conclusions: The sensitivity of MRI for diagnosing ramp lesions was significantly lower than that for medial meniscal body tears. Bone contusion of the posterior lip of the medial tibial plateau on MRI was not associated with ramp lesions., Level of Evidence: Level III, comparative trial., (Copyright © 2018 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

This prospective pilot study investigated whether grafting β-tricalcium phosphate (B-TCP) into the bone-patellar tendon-bone (BPTB)-harvesting site after anterior cruciate ligament reconstruction would accelerate bone and tendon regeneration in the grafted site. Overall, 19 patients agreed prospectively to undergo regular morphological and histological examinations of the B-TCP-grafted site. Postoperative radiographic, ultrasonographic, and magnetic resonance imaging (MRI) examinations were performed to evaluate the grafted site at 1, 3, 6, and 12 months. Postoperative knee function and donor-site morbidity were assessed at 12 months using the kneeling test. A histological examination was also performed at this time Radiographic examination and MRI showed that the grafted B-TCP was completely absorbed and remodeled into normal bone structure in the tibia and patella at 6 months postoperatively. Histological and ultrasonographic examinations of all subjects showed that the grafted B-TCP was substituted by normal bone tissue, and the patellar tendon - bone junction had regenerated at 12 months postoperatively. Clinical functional knee tests showed good recovery of the donor site. All patients could perform kneeling and knee walking on hard ground. The results of this pilot study suggest that grafting B-TCP into the BPTB-harvesting site promotes the remodeling process of the bone and patellar tendon structures. This surgical treatment would decrease an incidence of the anterior knee pain after ACLR using a BPTB autograft., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Background: Knee hyperextension and tibial posterior slope are related to sagittal alignment of the knee. The relationship of sagittal alignment to noncontact anterior cruciate ligament (ACL) injuries has been reported with conflicting results., Purpose: To determine whether there is a difference in sagittal alignment of the knee between an ACL-deficient group and a negative control group and to find risk factors contributing to noncontact ACL injuries., Study Design: Cross-sectional study; Level of evidence, 3., Methods: Magnetic resonance images of the knee in full extension were acquired in the patient group, which consisted of 33 male and 40 female patients with noncontact ACL injuries, and in the negative control group, which consisted of 28 male and 30 female participants. Three angles were measured: the angle between the femoral axis and the tibial axis, designated as the extension angle; the femoral plateau angle, between the femoral axis and a line tangent to the concave profile of the medial tibial plateau (P line); and the tibial posterior slope angle, 90° minus the angle made by the intersection of the tibial axis and the P line., Results: In the female group, the femoral plateau angle and the tibial posterior slope angle were significantly larger in the ACL-deficient patients than in the negative control group, although these differences were not seen in the male group. In the female subjects, a negative correlation between the extension angle and the tibial posterior slope angle was seen in the ACL-deficient group, suggesting that knees with hyperextension had a small tibial posterior slope, whereas knees without hyperextension had a large tibial posterior slope., Conclusion: There were 2 types of large femoral plateau angles: one had its origin in an increasing tibial posterior slope; the other resulted from hyperextension of the knee. Large posterior tibial slope and hyperextension are both correlated with noncontact ACL injury in women.

The aim of this study was to investigate the characteristics of proprioception in patients with an anaterior-cruciate-ligament (ACL)-injured knee and to determine whether there is a correlation between proprioception and performance. We studied 32 patients with unilateral isolated ACL ruptures. Proprioception of the knee was evaluated by examining the joint position sense. Functional performance was evaluated with the one-leg hop (OLH) and one-leg vertical jump (OLV) tests. The mean error angle of the joint position sense was 3.6+/-1.5 degrees on the intact side and 5.2+/-1.9 degrees on the injured side. The joint position sense was thus clearly reduced on the injured side (p<0.05). The distance of jumping in the OLH test and the height of jumping in the OLV test was also clearly reduced on the injured side compared with that on the intact side (p<0.01) both with and without visual control. Moreover, we found a significant correlation between proprioception and performance in the ACL-injured knees, and this correlation was more distinct with visual deprivation. In conclusion, decreased proprioception in patients with ACL deficiency reduced their functional ability.