Kinematic Analysis of Lateral Meniscal Oblique Radial Tears in the Anterior Cruciate Ligament–Deficient Knee

Background: Lateral meniscal oblique radial tears (LMORT) occur frequently in conjunction with anterior cruciate ligament (ACL) disruption and are anatomically distinct from meniscus root tears. Hypothesis/Purpose: The purpose of this study was to characterize the effects of LMORT types 3 (LMORT3) and 4 (LMORT4) lesions on joint stability and meniscal extrusion in ACL-deficient knees. Our hypothesis was that both lesions would promote significant increases in anterior translation and meniscal extrusion, with the LMORT4 lesion having a greater effect. Study Design: Controlled laboratory study. Methods: Two matched pairs of cadaveric knees (n = 4) were used to optimize the testing sequence. Additional cadaveric knees with LMORT3 (n = 8) and LMORT4 (n = 8) lesions created after ACL transection underwent robotic kinematic testing for anterior drawer and pivot-shift simulations with associated ultrasound-measured meniscal extrusion at clinically relevant knee flexion angles. Results: Optimization testing showed no differences on the effect of LMORT4 lesions for anterior translation and lateral meniscal extrusion with ACL-intact versus ACL-deficient knees. ACL deficiency and LMORT3 and LMORT4 lesions with ACL deficiency were associated with significantly greater anterior translation compared with ACL-intact state for both anterior drawer and pivot-shift testing at all flexion angles ( P < .001). ACL deficiency with either LMORT3 or LMORT4 lesion was associated with significantly greater anterior translation than was ACL deficiency only ( P < .005) for anterior drawer testing at 90° of flexion. Meniscal extrusion was greater with LMORT3 and LMORT4 lesions compared with ACL deficiency only ( P < .05) for anterior drawer at 60° of flexion and for pivot shift at 15° of flexion. The LMORT4 lesion demonstrated increased anterior translation for anterior drawer ( P = .003) at 60° of flexion (12%) as well as for pivot shift at 15° of flexion (7%) and 30° of flexion (13%) ( P < .005) compared with ACL deficiency only. Conclusion: In this cadaveric model, the addition of an LMORT3 or LMORT4 lesion increased anterior laxity for both the anterior drawer and the pivot shift when compared with an isolated ACL tear. Lateral meniscal extrusion was also exacerbated by these LMORT lesions. Clinical Relevance: LMORT lesions, distinct from meniscus root tears, occur frequently in conjunction with ACL tears. This study characterized the biomechanical consequences of LMORT3 and LMORT4 lesions on joint stability and meniscal function, highlighting the importance of diagnosing and treating LMORT lesions at the time of ACL reconstruction.

The impact of feature extraction and selection for the classification of gait patterns between ACL deficient and intact knees based on different classification models

The anterior cruciate ligament (ACL) plays an important role in stabilizing translation and rotation of the tibia relative to the femur. Individuals with ACL deficiency usually demonstrate alterations in gait characteristics. Evidence indicates that walking speed, alterations in kinetics and kinematics on the ACL deficient limb, and inter-limb asymmetries between deficient and intact knees may contribute to poor long-term outcomes following ACL deficiency. They corrode function of the knee joint and put it at higher risk of degeneration. For the purpose of developing an automatic and highly accurate system for detection of ACL deficiency, this study investigated the classification capability of different dynamical features extracted from gait kinematic and kinetic signals when evaluating their impact on different classification models. A general feature extraction framework was proposed and various dynamical features, such as recurrence rate, determinism and entropy from the recurrence quantification analysis, fuzzy entropy, Teager-Kaiser energy feature and statistical analysis, were included. Different classification models, including support vector machine (SVM), K-nearest neighbor (KNN), naive Bayes (NB) classifier, decision tree (DT) classifier and ensemble learning based Adaboost (ELA) classifier, derived for discriminant analysis of multiple dynamical gait features were evaluated for a comparative study. The effectiveness of this strategy was verified using a dataset of knee, hip and ankle kinematic and kinetic waveforms from 43 patients with unilateral ACL deficiency. When evaluated with 2-fold, 10-fold and leave-one-out cross-validation styles, the highest classification accuracy for discriminating between groups of ACL deficient and contralateral ACL intact knees was reported to be 91.22 $$\%$$ % , 95.12$$\%$$ % and 96.34$$\%$$ % , respectively,by using the SVM classifier and the optimal feature set. For other four classifiers, KNN achieved the accuracy of 78.05$$\%$$ % , 85.37$$\%$$ % and 87.80$$\%$$ % , respectively. NB achieved the accuracy of 57.56$$\%$$ % , 60.98$$\%$$ % and 61.22$$\%$$ % , respectively. DT achieved the accuracy of 77.56$$\%$$ % , 80.49$$\%$$ % and 83.66$$\%$$ % , respectively. ELA achieved the accuracy of 73.66$$\%$$ % , 78.05$$\%$$ % and 79.27$$\%$$ % , respectively. Compared with other state-of-the-art methods, the results demonstrate superior performance and support the validity of the proposed method.

Femur originated genu varum in a patient with symptomatic ACL deficiency: a case report and review of literature

Background Anterior cruciate ligament (ACL) injury may be associated with genu varum. There are a few indications in which the varus deformity can be corrected at the time of ACL reconstruction. However, as the genu varum originates mostly from the tibia and the simultaneous presence of ACL deficiency and femur originated genu varum is uncommon, only a few papers have described their management for ACL deficient patients with femur originated genu varum. Case presentation A young patient visited our clinic with a complaint of right knee pain and giving way. Further work up revealed a full mid substance ACL tear, mild medial knee osteoarthritis and femur originated genu varum of his right knee. He was managed with simultaneous ACL reconstruction and distal femoral valgus osteotomy. Conclusions Any corrective osteotomy for genu varum should be performed at center of rotation angle. Isolated ACL reconstruction in patients with simultaneous ACL deficiency and genu varum may hasten the knee degeneration. Level of evidence IV

Lateral Extra-articular Tenodesis Contributes Little to Change In Vivo Kinematics After Anterior Cruciate Ligament Reconstruction: A Randomized Controlled Trial

Background: Lateral extra-articular tenodesis (LET) in combination with anterior cruciate ligament (ACL) reconstruction (ACLR) has been proposed to improve residual rotatory knee instability in patients having ACL deficiency. Purpose/Hypothesis: The purpose was to compare the effects of isolated ACLR (iACLR) versus LET in combination with ACLR (ACLR+LET) on in vivo kinematics during downhill running. It was hypothesized that ACLR+LET would reduce the internal rotation of the reconstructed knee in comparison with iACLR. Study Design: Controlled laboratory study. Methods: A total of 18 patients with ACL deficiency were included. All participants were randomly assigned to receive ACLR+ LET or iACLR during surgery. Six months and 12 months after surgery, knee joint motion during downhill running was measured using dynamic biplane radiography and a validated registration process that matched patient-specific 3-dimensional bone models to synchronized biplane radiographs. Anterior tibial translation (ATT; positive value means “anterior translation”) and tibial rotation (TR) relative to the femur were calculated for both knees. The side-to-side differences (SSDs) in kinematics were also calculated (operated knee–contralateral healthy knee). The SSD value was compared between ACLR+LET and iACLR groups using a Mann-Whitney U test. Results: At 6 months after surgery, the SSD of ATT in patients who had undergone ACLR+LET (–1.9 ± 2.0 mm) was significantly greater than that in patients who had undergone iACLR (0.9 ± 2.3 mm) at 0% of the gait cycle (foot strike) ( P = .031). There was no difference in ATT 12 months after surgery. Regarding TR, there were no differences between ACLR+LET and iACLR at either 6 months ( P value range, .161-.605) or 12 months ( P value range, .083-.279) after surgery. Conclusion: LET in combination with ACLR significantly reduced ATT at the instant of foot strike during downhill running at 6 months after surgery. However, this effect was not significant at 12 months after surgery. The addition of LET to ACLR had no effect on TR at both 6 and 12 months after surgery. Clinical Relevance: LET in combination with ACLR may stabilize sagittal knee motion during downhill running in the early postoperation phase, but according to this study, it has no effect on 12-month in vivo kinematics. Registration: NCT02913404 ( ClinicalTrials.gov identifier)

Outcomes of Combined Unicondylar Knee Arthroplasty and Anterior Cruciate Ligament Reconstruction

Young and more active patients with medial compartmental osteoarthritis (OA) in conjunction with anterior cruciate ligament (ACL) deficiency are challenging for orthopaedic surgeons. The aim of the present study was to examine the early–mid clinical and radiological outcomes of combined Oxford unicondylar knee arthroplasty (UKA) and ACL reconstruction for the patients presenting ACL deficiency and concomitant medial compartment symptomatic OA. Twelve patients were included in the study. All patients were treated by combination of ACL reconstruction with medial UKA. The varus–valgus angles of the tibial and femoral components, and pathological radiolucent lines were measured on anteroposterior and lateral knee radiographs. Clinical evaluations include knee osteoarthritis outcome score (KOOS pain, symptom, daily life, sports, and quality of life), Oxford knee score (OKS), EQ-5D-3L, and EQ-visual analog scale (VAS). All the patients were followed up for an average of 45.6 months. The leg alignment showed 3.6 degrees ± 1 of varus deformity before surgery and 2.6 degrees ± 1 of valgus after surgery. With the exception of KOOS sports (p > 0.001), the KOOS pain, symptom, daily life, and quality of life, OKS, EQ-5D-3L, and EQ-VAS improved significantly after surgery (p < 0.001). Preoperative knee instability showed anterior translation of 5 to 10 mm in eight patients and >10 mm in four patients. There were no complications at follow-up. The early–mid clinical data have shown that UKA in conjunction with ACL reconstruction has revealed promising results. However, long-term follow-up studies are required to confirm the combined procedure in these patients.