Asymmetries in Dynamic Valgus Index After Anterior Cruciate Ligament Reconstruction: A Proof-of-Concept Study

Individuals with anterior cruciate ligament reconstruction (ACLR) are at a higher risk for subsequent anterior cruciate ligament (ACL) tears. Risk factors for ACL injuries likely involve a combination of anatomical, biomechanical, and neuromuscular factors. Dynamic knee valgus has been indicated as a possible biomechanical factor for future ACL injuries. Given that knee valgus is often accompanied by contralateral pelvic drop during single-leg activities, a dynamic valgus index (DVI) that quantifies combined kinematics of the knee and hip in the frontal plane has recently been developed. As the premise of asymmetrical DVI between limbs in the ACLR population has not been examined, this cross-sectional study was conducted with the aim to compare DVI between individuals with ACLR and healthy controls. Videos were taken for 12 participants with ACLR and 20 healthy controls when they performed single-leg hopping. One-way ANOVA revealed a higher DVI in the injured limb of the ACLR group when compared to their non-injured limb and to the healthy limb of the control group. As our data showed increased DVI in the injured limb of the ACLR group, the DVI approach accounting for hip and knee kinematics may be used to identify frontal plane movement deficits during single-leg hopping in individuals with ACLR.

Kinect Azure–Based Accurate Measurement of Dynamic Valgus Position of the Knee—A Corrigible Predisposing Factor of Osteoarthritis

(1) Dynamic knee valgus is a predisposing factor for anterior cruciate ligament rupture and osteoarthritis. The single-leg squat (SLS) test is a widely used movement pattern test in clinical practice that helps to assess the risk of lower-limb injury. We aimed to quantify the SLS test using a marker-less optical system. (2) Kinect validity and accuracy during SLS were established by marker-based OptiTrack and MVN Xsens motion capture systems. Then, 22 individuals with moderate knee symptoms during sports activities (Tegner > 4, Lysholm > 60) performed SLS, and this was recorded and analyzed with a Kinect Azure camera and the Dynaknee software. (3) An optical sensor coupled to an artificial-intelligence-based joint recognition algorithm gave a comparable result to traditional marker-based motion capture devices. The dynamic valgus sign quantified by the Q-angle at the lowest point of the squat is highly dependent on squat depth, which severely limits its comparability among subjects. In contrast, the medio-lateral shift of the knee midpoint at a fixed squat depth, expressed in the percentage of lower limb length, is more suitable to quantify dynamic valgus and compare values among individual patients. (4) The current study identified a new and reliable way of evaluating dynamic valgus of the knee joint by measuring the medial shift of the knee-over-foot at a standardized squat depth. Using a marker-less optical system widens the possibilities of evaluating lower limb functional instabilities for medical professionals.

INTRA AND INTER-RATER RELIABILITY IN DYNAMIC VALGUS IN SOCCER PLAYERS

ABSTRACT Introduction: The two-dimensional (2D) methods of dynamic assessment of knee valgus are popular because of their low cost and the fact that they are easy to implement. It is believed that dynamic valgus of the knee is one of the main disorders responsible for non-contact lesions of the anterior cruciate ligament. There are two categories of reliability with regard to data collectors: inter-rater (reliability among multiple data collectors) and intra-rater (reliability of a single data collector). Objectives: To assess intra and inter-rater reliability during the step-down test in professional soccer athletes, using initial and final angles for each test repetition. Methods: The sample consisted of 29 professional soccer players. All study participants were considered by club physiotherapists to be free of any musculoskeletal injury and were performing daily training tasks. Two male evaluators participated in the study. Results: For each data group, mean and standard deviation were determined. The intra- and inter-rater reliability of all data was determined using the intraclass correlation coefficient (ICC), with a confidence interval of 95% and alpha of p ≤ 0.05. Rater 1 was classified in the first intra-rater stage of the analysis for heel touch, with good to excellent reliability. For the inter-rater analysis, both for heel touch and for greater valgus angle, there was excellent reliability among the raters. Conclusion: It was concluded that there is high inter-rater and intra-rater reliability through two-dimensional analysis using the Step Down Test in professional soccer athletes. Level of evidence II; Development of diagnostic criteria in consecutive patients (with a “gold” reference standard applied).

Comparative Analysis of the Effect of the Different Adaptations of the Squat Exercise on the Knee Frontal Plane Projection Angle

Closed kinetic chain exercises have been employed in rehabilitation and muscle strengthening programs, such as squatting. During the movement of the squat dynamic valgus, a change that affects all kinematics of the lower limb, tends to become exacerbated, necessitating adaptations in order to minimize the biomechanical disorder. Although studies have shown the effectiveness of squatting exercises, there is a lack of evidence to demonstrate, comparatively, the effectiveness of different adaptations in the decrease of dynamic valgus. The objective of the study was to evaluate to identify the efficacy of different adaptations in squatting exercise in the reduction of dynamic valgus. Therefore, study volunteers (n = 30) performed three types of squats: free squatting, squatting with elastic band and squatting with verbal command. The dynamic valgus wasmeasured by the knee frontal plane projection angle during the squatting movements, through captured images and analyzed by the software Tracker and ImageJ. Despite more cases in women, in both sexes, free squatting presented greater cases of medicalization of the knee than in comparison to the other two adaptations. Although both squat adaptations presented positive results, only squatting with verbal command showed a significant reduction of the dynamic valgus pointing out that this is the best adaptation treated. Keywords: Genu Valgum. Exercise Therapy. Motor Activity. Resumo Exercícios de cadeia cinética fechada vêm sendo empregados em programas de reabilitação e fortalecimento muscular, como é o caso do agachamento. Durante o movimento de agachamento o valgo dinâmico, alteração que afeta toda cinemática do membro inferior, tende a se tornar exacerbado, sendo necessárias adaptações com o intuito de minimizar o distúrbio biomecânico. Embora estudos tenham mostrado a eficácia dos exercícios de agachamento, faltam evidências que demonstrem, comparativamente, a efetividade de diferentes adaptações na minimização do valgo dinâmico. O objetivo do estudo foi identificar a eficácia de diferentes adaptações na execução do exercício de agachamento na redução do valgo dinâmico. Para tanto, os voluntários do estudo (n=30) três tipos de agachamentos: agachamento livre, agachamento com banda elástica e agachamento com comando verbal. O valgo dinâmico foi mensurado mediante o ângulo de projeção no plano frontal do joelho durante os movimentos de agachamento, através de imagens capturadas e posteriormente analisadas pelos softwares Tracker e ImageJ. Apesar de mais casos em mulheres, em ambos os sexos, o agachamento livre apresentou maiores casos de medicalização do joelho do que nas outras duas adaptações. Embora ambas adaptações de agachamento apresentaram resultados positivos, apenas o agachamento com comando verbal apresentou redução significativa do valgo dinâmico, apontando ser esta a melhor adaptação tratada. Palavras-chaves: Geno Valgo. Terapia por Exercício. Atividade Motora.

The Effect of Osseous Valgus Alignment and Posteromedial Ligament Complex Deficiency on ACL Graft Forces: Risk Factors for Failure of ACL Reconstruction

Aims and Objectives: Dynamic valgus moments are known risk factors for ACL (re-)injuries. However, the association between osseous valgus alignment and ACL stress is not fully understood. The aim of the present study was to biomechanically investigate the influence of osseous valgus alignment, with and without deficiency of the medial collateral ligament and posterior oblique ligament (= posteromedial ligament complex; PMC), on ACL-graft forces under axial load. Additionally, it was investigated whether PMC reconstruction alone, correction osteotomy alone or a combination of both procedures were capable to decrease ACL-graft forces. Materials and Methods: The native ACL was dissected and ACL reconstruction was performed on ten cadaveric knee joints. A lateral distal femur osteotomy was done to adjust for three different alignment conditions according to the position where the axial weight bearing line (WBL) dissected the tibial plateau (% from medial to lateral): straight leg (50%), medium valgus (85%) and high-grade valgus (115%). Each alignment condition was tested with the PMC intact, deficient and reconstructed. The specimens were placed in a testing rig in 15° of knee flexion with the tibia fixed and the femur mobile on an X-Y-table. Axial loads of 400 N were applied and changes of ACL-graft forces (via an attached load-cell) and dynamic valgus angle (DVA) (via 3D motion tracking) were recorded. Results: In the PMC intact state, lateralization of the WBL to 85% and to 115% led to significantly increased ACL graft forces (85% vs. 50%: 96.1 ± 25.0 N vs. 63.7 ± 22.0 N, p=0.010; 115% vs. 50%: 109.9 ± 24.5 N vs. 63.7 ± 22.0 N; p<0.001) and DVA (85% vs. 50%: 2.0 ± 1.2° vs. 0.0 ± 0.8°, p=0.027; 115% vs. 50%: 2.1 ± 1.3° vs. 0.0 ± 0.8°; p=0.027). Dissection of the PMC led to a significant increase of ACL graft forces and DVAs at 85% and 115% valgus alignment (p<0.001), but not at 50% alignment. In valgus aligned knees (85%) with additional PMC deficiency, reconstruction of the PMC alone was able to significantly decrease ACL graft forces (85% deficient vs. 85% reconstructed: 158.0 ± 47.3 N vs. 112.1 ± 28.8 N; p<0.001) and DVA (85% deficient vs. 85% reconstructed: 7.4 ± 4.0° vs. 3.0 ± 2.0°; p<0.001). However, alignment correction alone was significantly more effective in reducing ACL graft forces (85% reconstructed vs. 50% deficient: 112.1 ± 28.8 N vs. 81.5 ± 23.8 N, p<0.001) and DVA (85% reconstructed vs. 50% deficient: 3.0 ± 2.0° vs. 0.81.0°; p=0.010). These relations were similar for high grade valgus alignment (115%). Conclusion: Osseous valgus alignment led to significantly increased ACL graft forces and DVA under axial joint compression, which was even further enhanced, when the PMC was deficient. In the valgus aligned and PMC deficient knee, correction to a straight leg axis was significantly more effective in decreasing forces on the ACL graft than reconstruction of the PMC.

Effects of Hip Muscle Resistance Training With and Without Feedback on Trunk, Pelvis, and Lower Extremity Motions

Introduction: The present study aimed to compare hip muscle resistance training with and without feedback on trunk, pelvis, and lower extremity motions in frontal and sagittal planes among active females with dynamic valgus. Materials and Methods: Twenty-Nine active females (Mean±SD age: 22.8±2.4 years, height: 1.70±0.6 m, weight: 69±7.1 kg) were randomly assigned to a hip muscle resistance training with feedback group (n=15) or a hip muscle resistance training without feedback group (n=14). Both training programs lasted 6 weeks (3 sessions/week). The peak angles of lateral trunk flexion, contralateral pelvic drop, hip flexion, knee flexion, and valgus during single-leg drop landing and single-leg vertical drop jump were assessed in the research participants at baseline and 6 weeks post-training. Unipodal functional screening tests were captured with two standard digital video cameras. Results: After 6 weeks, significant differences were observed in knee valgus and lateral trunk flexion, contralateral pelvic drop, and knee flexion angles, i.e., compared between hip muscle resistance training with feedback and hip muscle resistance training without feedback (P<0.05), except for non-dominant leg hip flexion in single-leg vertical drop jump (P>0.05). Conclusion: In the explored active females with dynamic valgus, hip muscle resistance training with feedback seems to be better at improving trunk, pelvis, and lower extremity motions in frontal and sagittal planes, compared to hip muscle resistance training without feedback; however, no significant difference was observed concerning hip flexion during single-leg vertical drop jump between the study groups.