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Anatomical reinsertion is the optimal treatment for meniscal root injuries. However, in chronic settings, tissue fraying of the meniscal root may impede it. This study describes a salvage technical procedure performed in 3 cases of chronic anterior root avulsion of the lateral meniscus with profuse tissue degeneration in which remnant debridement resulted in amputation of the root. Reinsertion of the meniscus at the remaining healthy tissue was performed using an all-inside anchoring technique., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Introduction: Implantation of autogenous meniscal fragments wrapped with a fascia sheath significantly enhances fibrocartilage regeneration in vivo in defect cases at 12 weeks after implantation. The specific effects of the implanted autologous living chondrocytes and meniscal matrix have not been elucidated, however. The aim of this study was to clarify the role of autologous living chondrocytes contained in the meniscal matrix in in vivo meniscus regeneration induced by in situ meniscus fragment implantation., Hypothesis: Implantation of meniscus fragments containing autologous living chondrocytes may result in significant in vivo meniscus regeneration., Materials and Methods: Seventy-five rabbits were used in this study. A partial meniscectomy of the anterior one-third of the medial meniscus including the part of the anterior horn was performed. The rabbits were divided into 3 groups. In Group I, no treatment was applied to the defect. In Group II, the autogenous meniscal fragments devitalized by freeze-thaw treatment were reimplanted into the defect. In Group III, the autogenous meniscal fragments were reimplanted. In each group, the defect was covered with a fascia. Five rabbits from each group were subjected to morphologic and histologic evaluations at 3, 6, and 12 weeks, and 5 rabbits from each group were subjected to biomechanical evaluations at 6 and 12 weeks., Results: Histologically, no cells were seen in the grafted meniscal fragments at 3 weeks in Group II, whereas chondrocytes in the grafted meniscal fragments were alive at 3 weeks in Group III. Histologic and biomechanical data for Group II were slightly but significantly better than those of Group I at 12 weeks after implantation (p=0.007 and p=0.002, respectively), whereas the data for Group III were significantly superior to those of Groups I and II at 12 weeks (p<0.0014 and p<0.0029, respectively)., Discussions: Grafted autologous living chondrocytes contained in the meniscal matrix play an important role in in vivo meniscus regeneration induced by in situ meniscus fragment implantation., Study Design: II, Controlled laboratory study., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Background: Medial meniscus posterior root tear (MMPRT) results in joint overloading and degenerative changes in the knee. Favorable clinical outcomes have been reported after transtibial pullout repair of MMPRT. To date, however, in vivo tibial rotational changes before and after root repair remain poorly understood. The purpose of this study was to investigate postoperative changes in tibial rotation following MMPRT pullout repair., Hypothesis: Pathological external rotation of the tibia in the knee-flexed position is caused by MMPRT and is reduced after transtibial pullout repair., Patients and Methods: Fifteen patients who underwent MMPRT pullout repair and 7 healthy volunteers were included. Magnetic resonance imaging examinations were performed in the 10° and 90° knee-flexed positions. The angles between the surgical epicondylar axis and a line between the medial border of the patellar tendon and the apex of the medial tibial spine were measured. Baseline was defined as a line lying at a right angle to the other, and a value was positive and negative when the tibia rotated internally and externally, respectively., Results: In the volunteer's normal knees, tibial internal rotation was +1.00°±3.27° at 10° flexion and +4.14°±3.46° at 90° flexion. In the MMPRT preoperative knees, tibial internal rotation was +1.07°±3.01° at 10° flexion and +1.27°±2.96° at 90° flexion. In the postoperative knees, tibial internal rotation was +1.60°±2.85° at 10° flexion and +4.33°±2.89° at 90° flexion., Discussion: This study demonstrates discontinuity of the MM posterior root may induce a pathological external rotation of the tibia during knee flexion and that MMPRT pullout repair reduces the pathological external rotation of the tibia in the knee-flexed position., Level of Evidence: III, comparative retrospective study., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Background: A medial meniscus posterior root tear (MMPRT) is defined as an injury to the posterior meniscal insertion on the tibia. In MMPRT, the medial meniscus (MM) hoop function is damaged, and the MM undergoes a medial extrusion into the interior from the superior articular surface of the tibia. However, the details of MM position and movement during knee joint movement are unclear in MMPRT cases. The present study aims to evaluate MM position and movement via magnetic resonance imaging (MRI) examination of the MM posterior extrusion (MMPE) at knee flexion angles of 10° and 90°. We hypothesized that, during knee flexion, the MM will shift to the posterior and the posterior extrusion will increase compared to that when the knee is extended., Materials and Methods: Twenty-four patients were diagnosed with symptomatic MMPRT on open MRI examination. Preoperative MMPE, anteroposterior interval (API) of the MM, and MM medial extrusion (MMME) at knee flexion angles of 10° and 90° were measured., Results: For patients with MMPRT, the MMPE increased from -4.77±1.43mm to 3.79±1.17mm (p<0.001) when the knee flexion angle increased from 10° to 90°. Further, flexing the knee from 10° to 90° decreased the API of the MM from 20.19±4.22mm to 16.41±5.14mm (p<0.001). MMME showed no significant change between knee flexion angles of 10° and 90°., Discussion: This study demonstrated that, in cases of MMPRT, the MMPE clearly increases when the knee is flexed to 90°, while MMME does not change. Our results suggest that open MRI examination can be used to evaluate the dynamic position of the posterior MM by scanning the knee as it flexes to 90°., Level of Evidence: IV: retrospective cohort study., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Introduction: The purpose of the current study was to compare the gait patterns in patients with three differing knee pathologies - knee osteoarthritis (OA), degenerative meniscal lesion (DML) and spontaneous osteonecrosis of the knee (SONK) and a group of healthy controls., Hypothesis: A simple gait test will detect differences between different knee pathologies., Material and Methods: Forty-seven patients with bilateral knee OA, 47 patients with DML, 28 patients with SONK and 27 healthy controls were included in this analysis. Patients underwent a spatiotemporal gait assessment and were asked to complete the Western Ontario and McMaster University (WOMAC) Index and the Short-Form (SF)-36 Health Survey. ANOVA tests, followed by Bonferroni multiple comparison tests and the Chi 2 tests were performed for continuous and categorical variables, respectively., Results: Significant differences were found for all gait measures and clinical questionnaires between healthy controls and all knee conditions. Patients with SONK differed from patients with bilateral knee OA and DML in all gait measures and clinical questionnaires, except for WOMAC subscales. There were no significant differences between patients with bilateral knee OA and patients with DML. Symmetry was also examined and revealed asymmetry in some gait parameters in patients with SONK and DML., Discussion: Based on the differences in gait parameters that were found in the current study, adding an objective functional spatiotemporal gait test may assist in the diagnostic process of knee pathologies., Type of Study: Case Control study Level III., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)