Extensor Torque Research Articles

Correlation Between Y-Balance Test and Balance, Functional Performance, and Outcome Measures in Patients Following ACL Reconstruction.

BackgroundThe Y-Balance test (YBT) is commonly used to evaluate balance after anterior cruciate ligament reconstruction (ACLR). However, several studies have also used it as a functional performance test (FPT).PurposeThis study aimed to examine the relationship between YBT scores and measures of knee joint laxity, static balance, knee flexor and extensor torque and strength ratio, and FPTs.Study DesignRetrospective cohort study.MethodsFifty-nine patients who underwent ACLR using hamstring autografts were retrospectively analyzed. The Pearson correlation coefficient was used to determine the strength of the association between scores on the YBT and selected outcomes including laxity measured via the KT-2000 arthrometer, static balance measured via the Biodex Balance System, isokinetic muscle torque and hamstring-to-quadriceps (HQ) ratio, and performance on the single leg hop test and the single leg vertical jump test.ResultsForty-six men and 13 women were included. The mean age and follow-up period were 29.6 ± 9.6 years and 12.4 ± 2.1 months, respectively. The KT-2000 arthrometer measures, Biodex Balance System scores, and HQ ratio measurements were not significantly correlated with the YBT scores. All YBT scores, except the YBT-anterior score, correlated with the isokinetic extensor and flexor torques (r-values: 0.271–0.520). All the YBT scores had significant weak to moderate correlations with the single leg hop test and single leg vertical jump test scores: YBT-anterior (r = 0.303, r = 0.258), YBT-posteromedial (r = 0.475, r = 0.412), YBT-posterolateral (r = 0.525, r = 0.377), and YBT-composite (r = 0.520, r = 0.412).ConclusionPost-ACLR YBT scores correlated with functional performance and muscle strength, but not with static balance, joint laxity, and HQ ratios. The YBT scores as a measure of balance are related to improved functional performance and isokinetic torque measures.Level of evidence3

Relationship between Isokinetic Knee Strength and Speed, Agility, and Explosive Power in Elite Soccer Players

The aim of this study was to determine the relationship between the isokinetic characteristics of knee extensors and flexors with selected motor abilities: Speed, agility, and explosive power of lower extremities of professional football players in the preparation period of a yearly training cycle. Twenty-one players (age: 24.5 ± 3.9 years; body mass: 76.7 ± 4.7 kg and body height: 183.5 ± 5.5 cm) playing in the highest Polish soccer league participated in the study. The isokinetic concentric torque of the knee extensors and flexors was measured at 300°/s, 180°/s, and 60°/s velocities. Sprint performance was assessed in the 30 m sprint test (standing start). The forward, lateral, and backward movements were assessed using the T-Test of agility. Explosive power was quantified by performing the squat jump (SJ) and countermovement (CMJ), using the force platform. Due to sport-specific demands of soccer activities measured in this experiment, the relationships between peak torque (PT) and the 30 m sprint, T-Test of agility, and power of vertical jumps (SJ and CMJ) were low or medium at speeds of 60°/s and 300°/s. One of the main reasons for the lack of high dependence of the above-mentioned factors are that the measurements were performed during the initial training period where the level of individual abilities is at a low level. Additionally, this experiment may also indicate that the measurement of isokinetic knee flexion and extension peak is effective when performed at the correct angular velocity in relation to the evaluation of the intended motion structure.

Effect of the Knee and Hip Angles on Knee Extensor Torque: Neural, Architectural, and Mechanical Considerations.

This study examined the influence of knee extensors’ hip and knee angle on force production capacity and their neuromuscular and architectural consequences. Sixteen healthy men performed sub-maximal and maximal voluntary isometric contractions (MVIC) of knee extensors with four different combinations of the knee and hip angles. Muscle architecture, excitation-contraction coupling process, muscular activity, and corticospinal excitability were evaluated on the vastus lateralis (VL) and rectus femoris (RF) muscles. MVIC and evoked peak twitch (Pt) torques of knee extensors increased significantly (p < 0.05) by 42 ± 12% and 47 ± 16% on average, respectively, under knee flexed positions (110° flexion, 0° = full extension) compared to knee extended positions (20° flexion) but were not different between hip positions (i.e., 0° or 60° flexion). Knee flexion also affected VL and RF muscle and fascicle lengths toward greater length than under knee extended position, while pennation angle decreased for both muscles with knee flexion. Pennation angles of the VL muscle were also lower under extended hip positions. Alternatively, no change in maximal muscle activation or corticospinal activity occurred for the VL and RF muscles across the different positions. Altogether these findings evidenced that MVIC torque of knee extensors depended particularly upon peripheral contractile elements, such as VL and RF muscle and fascicle lengths, but was unaffected by central factors (i.e., muscle activation). Furthermore, the hip position can affect the pennation angle of the VL, while VL muscle length can affect the pennation angle of the RF muscle. These elements suggest that the VL and RF muscles exert a mutual influence on their architecture, probably related to the rectus-vastus aponeurosis.

Utilization of Mid-Thigh Magnetic Resonance Imaging to Predict Lean Body Mass and Knee Extensor Strength in Obese Adults.

Purpose:To train and test a machine learning model to automatically measure mid-thigh muscle cross-sectional area (CSA) to provide rapid estimation of appendicular lean mass (ALM) and predict knee extensor torque of obese adults.Methods:Obese adults [body mass index (BMI) = 30–40 kg/m2, age = 30–50 years] were enrolled for this study. Participants received full-body dual-energy X-ray absorptiometry (DXA), mid-thigh MRI, and completed knee extensor and flexor torque assessments via isokinetic dynamometer. Manual segmentation of mid-thigh CSA was completed for all MRI scans. A convolutional neural network (CNN) was created based on the manual segmentation to develop automated quantification of mid-thigh CSA. Relationships were established between the automated CNN values to the manual CSA segmentation, ALM via DXA, knee extensor, and flexor torque.Results:A total of 47 obese patients were enrolled in this study. Agreement between the CNN-automated measures and manual segmentation of mid-thigh CSA was high (>0.90). Automated measures of mid-thigh CSA were strongly related to the leg lean mass (r = 0.86, p < 0.001) and ALM (r = 0.87, p < 0.001). Additionally, mid-thigh CSA was strongly related to knee extensor strength (r = 0.76, p < 0.001) and moderately related to knee flexor strength (r = 0.48, p = 0.002).Conclusion:CNN-measured mid-thigh CSA was accurate compared to the manual segmented values from the mid-thigh. These values were strongly predictive of clinical measures of ALM and knee extensor torque. Mid-thigh MRI may be utilized to accurately estimate clinical measures of lean mass and function in obese adults.

Muscle architecture of the vastus lateralis and rectus femoris in the production of knee extensor torque in physically inactive women

Aim: This study aimed to verify the data reliability of muscle architecture (MA) variables, and the relationship between MA and the isometric peak torque (PT) of the monoarticular and biarticular knee extensor (KE) muscle in physically inactive women. Methods: Ten physically inactive women (24.0 ± 1.64 years; 162.9 ± 5.34 cm; 63.5 ± 11.90 kg) participated in the study. An ultrasound device assessed the MA variables (muscle thickness, fascicle length, and pennation angle) of the Vastus Lateralis (VL) and Rectus Femoris (RF), and an isokinetic dynamometer assessed the PT. Pearson correlation evaluated the relationship between PT and MA variables, with a significance level of 5%. Additionally, the intraclass correlation coefficient, coefficient of variation, and standard error of measurement. Results: Excellent reliability between images was observed, and no significant relationships were observed between the PT and MA variables of the VL and RF. Conclusion: Isolated variables of the MA of a monoarticular or a biarticular muscle do not influence the production of the isometric PT of the KE.

Influence of biofeedback training time on muscle torque and knee excursion following semitendinosus release in spastic quadriplegic children with cerebral palsy: A randomized controlled trial

Background. Medial hamstring shortening represents a serious common complication in children suffering from spastic quadriplegic cerebral palsy. Objective. The purpose of the study was to examine the efficacy of biofeedback training timing following tendon release in spastic quadriplegic cerebral palsied children. Design. a prospective, single-blind, randomized controlled trial. Setting: several hospitals across Giza and Cairo, where children were operated. Methods. Thirty spastic quadriplegic cerebral palsied children of both genders, with their ages ranged from 7 to 9 years (x ̅ = 8.2 ± 0.86 yr.) were randomly assigned into two equal groups (A and B). The control group (A) was trained using electromyographic biofeedback daily for two weeks after removal of plaster cast, in addition to an hour/ day of a designed physical therapy program, while the study group (B) was trained by electromyographic biofeedback during the immobilization period and for two weeks after removal of the cast along with the same physical therapy program as the group (A). The knee extensors’ peak torque and knee excursion angle were measured immediately and two weeks following cast removal by MERAC isokinetic system and electro-goniometer, respectively. Results. The findings exhibited a significant increase (P &lt; 0.05) in the peak torque of knee extensors and an increase in knee excursion in the group (B) immediately and after two weeks of the cast removal when compared with the results of the group (A) after the same period. Conclusion. Applying electromyographic biofeedback training at the two-week immobilization period resulted in a strengthening of the quadriceps and maintaining the obtained range of knee extension following semitendinosus muscle release in spastic quadriplegic children with cerebral palsy.

Physiological Adaptations to High-Intensity Interval Training Combined with Blood Flow Restriction in Masters Road Cyclists.

High-intensity interval training (HIIT) and blood flow restriction (BFR) training have been used to enhance athletic performance and cardiovascular health. Combining these training modalities might be an effective training modality for masters athletes who seek to enhance athletic performance and to reduce cardiovascular risks. Fifty masters road cyclists age 35-49 yr were randomly assigned to the continuous exercise training (n = 16), continuous plus HIIT (n = 17), and continuous plus BFR training combined with HIIT (BFRIT; n = 17) for 12 wk. Both HIIT and BFRIT were performed on a cycle ergometer twice a week. Maximal oxygen consumption (V̇O2max) increased in the HIIT and BFRIT groups (P < 0.05). This was accompanied by significant improvements in maximal cardiac output and stroke volume (P < 0.05). Forty-kilometer time trial performance improved in all three groups (P < 0.05). Peak power output increased in both HIIT and BFRIT groups (P < 0.05). Flow-mediated dilation in both brachial and popliteal arteries increased in all three groups (all P < 0.05). There were no significant changes in carotid intima-media thickness and arterial stiffness in any of the groups. Total lean mass, muscle cross-sectional area and thickness in rectus femoris and vastus lateralis, and peak torque of isokinetic knee extension increased only in the BFRIT group (all P < 0.05). Tissue saturation index decreased only in the BFRIT group (P < 0.05). Changes in 40-km time trial performance were associated with corresponding changes in V̇O2max (r = -0.312, P = 0.029) and peak isokinetic extensor torque (r = -0.432, P = 0.002). Including HIIT particularly with BFR in the routine continuous training may be more effective in enhancing performance and physiological functions in masters road cyclists.

Relationship between vastus medialis Hoffmann reflex excitability and knee extension biomechanics during different tasks in women with patellofemoral pain

BackgroundImpaired knee extension biomechanics and spinal excitability have been reported in women with patellofemoral pain, but their relationship has not been explored. A significant relationship between them could indicate the need for investigating the potential benefits of disinhibitory interventions for women with patellofemoral pain. Thus, this study aimed to investigate the relationship between vastus medialis Hoffmann reflex and (1) maximal isometric, concentric and eccentric knee extensor strength and rate of torque development; (2) knee extensor torque steadiness; and (3) knee extensor moment during functional tasks; in women with patellofemoral pain. MethodsSpinal excitability of twenty-four participants was assessed by the amplitude of maximal vastus medialis Hoffmann reflex. Knee extensor strength, rate of torque development and torque steadiness were assessed using an isokinetic dynamometer. Knee extensor moment during step-down and stair descent tasks were obtained using a three-dimensional motion analysis system. FindingsA moderate negative relationship was found between vastus medialis Hoffmann reflex and knee extensor torque steadiness (r = −0.35; p = 0.05); whereas a moderate positive relationship was found with maximal isometric knee extensor strength (r = 0.37; p = 0.044). No significant relationships were found between vastus medialis Hoffmann reflex and the other variables. InterpretationOur findings provide insight on the relationship between spinal excitability and neuromuscular control of maximal and submaximal isometric torque production in women with patellofemoral pain. Conversely, spinal excitability does not seem to be related with dynamic torques and moments of the knee extensors in women with patellofemoral pain.

Rate of torque development of paretic lower limb is an excellent predictor of walking speed in chronic stroke individuals

BackgroundWalking speed discriminates levels of functionality in stroke survivors, but its relationship with neuromuscular parameters remains unclear. We aimed to (1) verify relationships between walking speed, peak torque, and rate of torque development in individuals with chronic stroke and (2) investigate whether adjusting the predictive model for assistive device use and lower limb motor function improves its accuracy. MethodsTwenty-nine stroke survivors (time post-stroke ≥6 months) were assessed for walking speed, motor function, torque of knee extensors, and rate of torque development. Hierarchical multiple regression was conducted to infer the contribution of assistive device use and lower limb motor function in the proportion of variance in walking speed explained by neuromuscular parameters. Adequacy of regression models was verified using Shapiro-Wilk test and visual inspection of histograms. FindingsRate of torque development measures presented higher coefficients of determination (R2 = 0.399–0.457) than peak torque (R2 = 0.333). However, no differences were observed between correlation coefficients (P > 0.05). When adjusted for assistive device use and lower limb motor function, coefficients of determination of all neuromuscular parameters were improved (P < 0.05). Regression models showed good adequacy. InterpretationPeak torque and rate of torque development from knee extensors are adequate predictors of walking speed in stroke survivors. Adjusting predictive models for assistive device use and lower limb motor function increases predictive capacity. These findings may have repercussions for assessing chronic stroke individuals and developing treatment strategies.

Prediction of Knee Injury in Professional Soccer Players Using Core Endurance and Strength: A Cross-sectional Study

Although relationships between lower limb injury and core strength and endurance have been reported, limited research on the risk of knee injury specifically among soccer players exists. This study aimed to compare preseason trunk muscle endurance as well as trunk and hip muscle strength between soccer players who experienced knee in- jury during their season and those who did not. Dependent variables were also used to predict the risk for injury. This prospective cross-sectional study involved thirty-nine male soccer players (age 19.64±2.84 years, weight 73.94±15.66 kg and height 175.67±9.92 cm). By the end of the season, twelve (30.77%) reported knee injuries. Accordingly, two groups were identified and compared: injured and non-injured. Prone-bridge, side-bridge, trunk flexion and hor- izontal back extension hold times were used as trunk endurance measures, while peak isokinetic trunk flexor and extensor torques, as well as hip abductor and external rotator torques, were recorded as strength measures. MANOVA showed that only prone-bridge hold time was significantly higher in the non-injured players (p&lt;0.05). Logistic re- gression showed that prone-bridge hold time and peak isokinetic hip abductor torque were significant predictors of injury (OR=0.97&amp;0.03, respectively). Thus, soccer players with knee injuries have lesser core endurance. Reduced prone-bridge hold time and abductor torque, specifically, are associated with an increased risk of injury.

Effect of Meniscal Treatment on Functional Outcomes 6 Months After Anterior Cruciate Ligament Reconstruction.

Background:Meniscal injuries are commonly associated with anterior cruciate ligament (ACL) tears. Treatment of meniscal injuries can impart delayed weightbearing and range of motion restrictions, which can affect the rehabilitation protocol. The effect of meniscal treatment and subsequent restrictions on strength recovery after ACL reconstruction is unclear.Purpose/Hypothesis:The purpose of this study was to compare strength, jumping performance, and patient-reported outcomes between patients who underwent isolated ACL reconstruction (ACLR) and those who underwent surgical intervention for meniscal pathology at the time of ACLR. Our hypothesis was that patients who underwent concurrent meniscal repair (MR) would have lower strength recovery owing to postoperative restrictions.Study Design:Cohort study; Level of evidence, 3.Methods:Patients with ACLR were stratified into isolated ACLR, ACLR and meniscectomy (ACLR-MS), or ACLR-MR groups and were compared with healthy controls. The ACLR-MR group was restricted to partial weightbearing and to 90° of knee flexion for the first 6 weeks postoperatively. All participants completed patient-reported outcomes (International Knee Documentation Committee [IKDC] and Knee injury and Osteoarthritis Outcome Score [KOOS]) and underwent bilateral isokinetic and isometric strength tests of the knee extensor and flexor groups as part of a return-to-sports test battery at 5 to 7 months postoperatively.Results:A total of 165 patients with ACLR (50 with isolated ACLR, 44 with ACLR-MS, and 71 with ACLR-MR) and 140 healthy controls were included in the study. Follow-up occurred at a mean of 5.96 ± 0.47 months postoperatively. The control group demonstrated higher subjective knee function, unilateral peak extensor torque, and limb symmetry than did the ACLR-MS and ACLR-MR groups combined (P < .001 for all). There were no differences in IKDC, KOOS subscales, or unilateral or limb symmetry measures of peak knee extensor or flexor torque among the isolated ACLR, ACLR-MS, and ACLR-MR groups.Conclusion:Persistent weakness, asymmetry, and reduced subjective outcome scores at 6-month follow-up after ACLR were not influenced by meniscal treatment. These findings suggested that the weightbearing and range of motion restrictions associated with meniscal repair recovery do not result in loss of early strength or worse patient-reported outcomes.

The Impact of Meniscal Treatment on Functional Outcomes Six Months After Anterior Cruciate Ligament Reconstruction (107)

Objectives:The incidence of anterior cruciate ligament (ACL) injuries continues to rise, and meniscal injuries are commonly associated with these tears. Treatment of meniscal injuries can impart delayed weightbearing range-of-motion restrictions, which can affect the post-operative rehabilitation protocol. These limitations after a meniscal repair could change how patients are managed and progressed through rehab. The effect of the meniscal treatment and subsequent restrictions on strength recovery after ACL reconstruction (ACLR) is unclear and may affect return-to-play assessments. The purpose of this study was to compare strength, jumping performance and patient reported outcomes between isolated ACLR patients and those undergoing surgical intervention for meniscal pathology at the time of ACLR surgery at a scheduled functional testing assessment an average of 6 months after surgery. Our hypothesis is that those undergoing meniscal repair will have lower strength recovery due to post-operative restrictions.Methods:In this retrospective cohort study, ACLR patients and healthy controls completed patient-reported outcomes (IKDC and KOOS), underwent bilateral isokinetic and isometric strength tests of the knee extensor and flexor groups, as well as functional hop testing as part of a return-to-sport test battery at 5-7 months post-operatively. ACLR patients were stratified as isolated ACLR, ACLR+Meniscectomy (ACLR-MS), ACLR+Meniscal Repair (ACLR-MR) and compared to healthy controls. Patients treated with meniscus repair were restricted to partial weight bearing and to 90 degrees of knee flexion for the first 6 weeks post-surgery. Comparisons were performed between meniscal treatment groups with regard to demographics, patient reported outcomes scales, knee extensor and flexor strength, while stratifying by graft type.Results:305 participants, including 165 ACLR patients (50 isolated ACLR, 71 ACLR + Meniscal Repair, 44 ACLR + Meniscectomy) and 140 healthy controls were included with an average time post-operatively to functional testing of 5.96±0.47 months. Heathy controls demonstrated higher subjective knee function, unilateral peak extensor torque, and limb symmetry than all meniscal subgroups (p<.001). There were no differences between the IKDC, KOOS subscales, or in unilateral or limb symmetry measures of peak knee extensor or flexor torque between ACLR, ACLR+MS, and ACLR+MR patients (all p-values>.05).Conclusions:Persistent weakness, asymmetry and reduced subjective outcome scores measured at approximately 6 months post index surgery were not influenced by meniscus treatment. Knee flexor and extensor strength, limb symmetry, and patient reported outcomes did not significantly differ across patients undergoing isolated ACLR, ACL + Meniscus Repair, and ACL + meniscectomy. These findings suggest that the weightbearing and range-of-motion restrictions associated with meniscus repair recovery do not result in loss of early strength or patient reported outcomes, and they can be progressed through therapy accordingly.

The ACL can hypertrophy in response to mechanical loading: an MRI study in elite athletes (157)

The ACL can hypertrophy in response to mechanical loading: an MRI study in elite athletes (157)

Effect of Dynamic Stretching versus Proprioceptive Neuromuscular Facilitation Stretching of Antagonist Muscle on Knee Extensor Torque and Dynamic Balance in Young Male Collegiate

Introduction: Many athletes perform stretching exercises as part of a warm-up prior to physical activity in order to prevent injuries and enhance their performance by an increase in flexibility. The significance of this study was that it may provide information about the better stretching method between dynamic and PNF stretching immediately before the sports events which may help to enhance the strength of knee extensor, thereby helping in improving performance and injury prevention.Method: An experimental design was used in the study. 51 subjects were randomly divided and statistically analysed for results. Group 1 had to under go dynamic stretching, Group 2 had to undergo PNF stretching for a period of four, and Group 3 (control group) did not undergo any kind of stretching. Results: It was observed that there was no significant difference in peak torque and average torque at 60⁰/s and 180⁰/s and SEBT scores after 4 weeks of dynamic vs PNF stretching. No significant difference was found in dynamic balance after 4 weeks of dynamic vs PNF stretching. Conclusion: We may infer that dynamic stretching and proprioceptive neuromuscular facilitation stretching of antagonist muscle have the same effect on knee extensor torque and dynamic balance in young collegiate males.

Intra- and Inter-Limb Strength Asymmetry in Soccer: A Comparison of Professional and Under-18 Players.

(1) Background: the present study examined the isokinetic peak torque exerted by both knee extensors and flexors, anterior–posterior imbalance and the magnitude and direction of inter-limb asymmetry in professional and academy soccer players. (2) Methods: one hundred soccer players (professional = 50, elite academy = 50) volunteered to take part in this investigation. An isokinetic dynamometer was used to measure the knee extensor (quadriceps) and flexors muscle (hamstrings) torques of the limbs as well as inter-limb asymmetries—using a standard percentage difference equation. (3) Results: professional players exhibited significantly greater (effect size [ES] = large) strength levels in the quadriceps and hamstrings under both testing conditions, significantly higher (small to moderate) intra-limb ratio values for 60°·s−1 but not for the 300°·s−1 test condition, significantly (small to moderate) lower inter-limb asymmetry values for all test conditions, with the exception of the hamstrings at 60°·s−1 and the direction of asymmetry was poor to slight, indicating that limb dominance was rarely the same between groups. (4) Conclusions: this study shows that isokinetic assessments, i.e., peak torque exerted by both knee extensors and flexors and intra-limb ratio, and the subsequent inter-limb asymmetry, i.e., magnitude and direction, can differentiate between professional and academy soccer players.

Knee flexor strength and symmetry vary by device, body position and angle of assessment following ACL reconstruction with hamstring grafts at long-term follow-up.

Persistent deficits in knee flexor strength following harvest of semitendinosus and gracilis for anterior cruciate ligament reconstruction are inconsistent in the literature. Variation in methodology, including measuring torque at higher knee flexion angles may partially explain these discrepant findings. The objective of this study was to determine whether positioning (seated vs supine), consideration of peak or joint-angle-specific torque or device (Isokinetic Dynamometer vs NordBord Hamstring Dynamometer) impact the magnitude of knee flexor strength differences between limbs. Participants (n = 31, 44.2 ± 10.7years,) who were at 14 ± 4.4years follow-up for unilateral ACL reconstruction with semitendinosus/gracilis grafts completed the ACL Quality of Life outcome and an assessment including isokinetic concentric knee extensor and flexor strength in seated and supine with peak torque and torque at 60° (T60) and 75° (T75) knee flexion measured, followed by an eccentric Nordic Hamstring Curl. Isokinetic concentric knee flexor torque was reduced in supine relative to seated, on the reconstructed limb against the unaffected, and at higher degrees of knee flexion relative to peak torque (T60 and T75 against peak torque). Limb symmetry varied by methodology (F(6,204) = 8.506, p = 0.001) with reduced symmetry in supine T75 against all measures (71.1 ± 16.5%, p < 0.05), supine T60 against seated peak torque (82.7 ± 14.2%, p < 0.05), and the NordBord was lower than seated peak torque that was not statistically significant (83.9 ± 12.8%, n.s.). Knee extensor peak (r2 = 0.167 (F(1,27) = 5.3, p = 0.03) and Nordic curl eccentric torque (r2 = 0.267, F(2,26) = 4.736, p = 0.02) were predictors of ACL-QoL score, although a combined model did not improve over Nordic torque alone. Limb symmetry cannot be assumed in clinical practice across differing assessment methods for knee flexor strength as deficits are greatest in the supine position with torque measured at 75° knee flexion. Isokinetic knee extensor and eccentric knee flexor torque during the Nordic hamstring curl were predictors of ACL-QoL scoring and should be considered alongside patient-reported outcomes for patients following ACL reconstruction with hamstring grafts. Level IV.

Quadriceps Tendon Versus Hamstring Tendon Autografts for Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis

Background: Autograft choice in anterior cruciate ligament reconstruction (ACLR) remains controversial, with increasing interest in the usage of quadriceps tendon (QT) autograft versus traditional hamstring tendon (HT) use. The current study undertakes an in-depth review and comparison of the clinical and functional outcomes of QT and HT autografts in ACLR. Hypothesis: The QT autograft is equivalent to the HT autograft and there will be little or no significant difference in the outcomes between these 2 autografts. Study Design: Systematic review and meta-analysis; Level of evidence, 4. Methods: The PUBMED, EMBASE, MEDLINE, and CENTRAL databases were systematically searched from their inception until November 2020. All observational studies comparing ACLR QT and HT autografts were assessed for their methodological quality. Patient outcomes were compared according to patient-reported outcome measures (International Knee Documentation Committee [IKDC], Cincinnati, Lysholm, Tegner, and visual analog scale [VAS] measures), knee extensor and flexor torque limb symmetry indices (LSIs), hamstring to quadriceps (H/Q) ratios, functional hop capacity, knee laxity, ipsilateral graft failure, and contralateral injury. Results: A total of 20 observational studies comprising 28,621 patients (QT = 2550; HT = 26,071) were included in the quantitative meta-analysis. In comparison with patients who received an HT autograft, those who received a QT autograft had similar postoperative Lysholm (mean difference [MD], 0.67; P = .630), IKDC (MD, 0.48; P = .480), VAS pain (MD, 0.04; P = .710), and Cincinnati (MD, -0.85; P = .660) scores; LSI for knee flexor strength (MD, 6.06; P = .120); H/Q ratio (MD, 3.22; P = .160); hop test LSI (MD, -1.62; P = .230); pivot-shift test grade 0 (odds ratio [OR], 0.80; P = .180); Lachman test grade 0 (OR, 2.38; P = .320), side-to-side laxity (MD, 0.09; P = .650); incidence of graft failure (OR, 1.07; P = .830) or contralateral knee injury (OR, 1.22; P = .610); and Tegner scores (MD, 0.11; P = .060). HT autografts were associated with a higher (better) side-to-side LSI for knee extensor strength (MD, -6.31; P = .0002). Conclusion: In this meta-analysis, the use of the QT autograft was equivalent to the HT autograft in ACLR, with comparable graft failure and clinical and functional outcomes observed. However, HT autografts were associated with better LSI knee extensor strength.

Comparison of Functional Outcomes, Femoral Rollback and Sagittal Stability of Anterior-Stabilized Versus Posterior-Stabilized Total Knee Arthroplasty: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

Total knee arthroplasty (TKA) has improved leaps and bounds in terms of design to improve clinical outcomes and achieve better rehabilitation of the patients. Ultra-congruent inserts (UC) were designed to replace the need for posterior stabilized (PS) implants. The purpose of this review was to evaluate clinical outcomes, femoral rollback, functional scores, range of motion, sagittal laxity, complication rates, and isokinetic performance between UC and PS TKA among RCTs. Electronic databases such as PubMed, Scopus, opengrey, and Cochrane were searched from date of inception up to mid-April 2021, and meta-analysis was performed following PRISMA guidelines. This study analyzed outcomes, femoral rollback, tibial sagittal laxity and isokinetic performance. Ten RCTs identified 852 knees, of which 420 underwent UC TKAs and 432 underwent PS TKA. Compared to UC TKA, a significantly better sagittal stability (p = 0.17) and femoral rollback (p < 0.00001) in PS TKAs was noted, although no statistically significant difference was found in the assessment of the range of motion (p = 0.19) and functional scores. Both the groups had similar isokinetic performance with extensor torque (p = 0.97) and flexor torque (p = 0.37). We conclude with the current meta-analysis that there are no addedbenefits for UC over PS inserts and these insertshave a higher sagittal laxity and less femoral roll backin cruciate sacrificing UC knee. But since there are no long-term wear data, UC inserts with CS technique should be used cautiously and may be used only when the PCL cannot be balanced adequately. There is no evidence or only a few to support the superiority of the AS TKA in terms of clinical outcomes or isokinetic performance or femoral external rotation over PS TKA. Level I, Systematic review and meta-analysis of RCTs.

Resistance training rejuvenates the mitochondrial methylome in aged human skeletal muscle.

Resistance training (RT) dynamically alters the skeletal muscle nuclear DNA methylome. However, no study has examined if RT affects the mitochondrial DNA (mtDNA) methylome. Herein, ten older, Caucasian untrained males (65±7 y.o.) performed six weeks of full-body RT (twice weekly). Body composition and knee extensor torque were assessed prior to and 72h following the last RT session. Vastus lateralis (VL) biopsies were also obtained. VL DNA was subjected to reduced representation bisulfite sequencing providing excellent coverage across the ~16-kilobase mtDNA methylome (254 CpG sites). Biochemical assays were also performed, and older male data were compared to younger trained males (22±2 y.o., n=7, n=6 Caucasian & n=1 African American). RT increased whole-body lean tissue mass (p=.017), VL thickness (p=.012), and knee extensor torque (p=.029) in older males. RT also affected the mtDNA methylome, as 63% (159/254) of the CpG sites demonstrated reduced methylation (p<.05). Several mtDNA sites presented a more "youthful" signature in older males after RT in comparison to younger males. The 1.12 kilobase mtDNA D-loop/control region, which regulates replication and transcription, possessed enriched hypomethylation in older males following RT. Enhanced expression of mitochondrial H- and L-strand genes and complex III/IV protein levels were also observed (p<.05). While limited to a shorter-term intervention, this is the first evidence showing that RT alters the mtDNA methylome in skeletal muscle. Observed methylome alterations may enhance mitochondrial transcription, and RT evokes mitochondrial methylome profiles to mimic younger men. The significance of these findings relative to broader RT-induced epigenetic changes needs to be elucidated.

Isokinetic torque analysis demonstrates deficits in knee flexor and extensor torque in patients at 9–12 months after anterior cruciate ligament reconstruction, despite peak torque symmetry

BackgroundLower limb strength asymmetry is associated with re-injury after anterior cruciate ligament reconstruction (ACLR). This study investigated limb symmetry indices (LSIs) during isokinetic knee extensor and flexor assessment after ACLR. MethodsOverall, 25 patients underwent isokinetic knee extensor and flexor strength assessment, 9–12 months after ACLR with a semitendinosus autograft. While patients were included if they presented with peak knee extensor (PKET) and flexor (PKFT) torque LSIs ≥ 90%, LSIs were calculated at designated points throughout the isokinetic torque range of motion, including: 15°, 30°, 45°, 60° and 75° (from 90° of knee flexion) during PKET and 15°, 30°, 45°, 60° and 75° (from full knee extension) during PKFT. T-tests investigated limb differences for PKET and PKFT, as well as at the final 75° assessment point during knee extension and flexion, between: (1) males and females, (2) those that did, or did not, undergo meniscal surgery, and (3) those undergoing ACLR on their dominant or non-dominant limb. ResultsSignificant differences between limbs were observed for PKET at 15° (p = 0.040) and 75° (p = 0.002), and for PKFT at 60° (p = 0.001) and 75° (p < 0.0001). No comparative differences (p > 0.05) were seen based on gender, meniscal surgery or whether ACLR was on the dominant or non-dominant limb. ConclusionDespite 100% of patients demonstrating PKET and PKFT LSIs ≥ 90%, LSI differences existed at designated points throughout the knee extensor and flexor torque range of motion. Analysis of torques throughout full range should be considered in future studies, as comparison of isolated peak measures miss strength deficits.