Prolonged quadriceps latency during gait early after anterior cruciate ligament injury predicts radiographic knee osteoarthritis 6-years after anterior cruciate ligament reconstruction.

BACKGROUND: The purpose was to explore quadriceps electromechanical function (quadriceps latency) during gait after anterior cruciate ligament injury as a predictor for radiographic knee osteoarthritis 6-years after anterior cruciate ligament reconstruction. Change in latency after preoperative physical therapy was also examined. METHODS: Quadriceps latency (time between peak knee moment and quadriceps electromyography) was calculated before preoperative physical therapy (2.4 [0.5-7.5] months after anterior cruciate ligament injury) and after preoperative physical therapy in 24 athletes. Participants were dichotomized into osteoarthritis (Kellgren and Lawrence grade ≥ 2) and non-osteoarthritis groups at 6-years. Forward selection logistic regression was performed using z-score normalized quadriceps latency and demographics. A 2 × 2 repeated measure ANOVA was performed for quadriceps latency between groups before and after preoperative physical therapy. FINDINGS: Quadriceps latency before preoperative physical therapy was the only predictor of 6-year radiographic osteoarthritis (p = 0.014, odds ratio [95% confidence interval] = 5.859 [1.435-23.924]). Time by group interaction was observed for quadriceps latency (p = 0.039, η2p = 0.179). In the osteoarthritis group, latency may reduce after training (before preoperative physical therapy = 115.7 ± 20.6 ms, after preoperative physical therapy = 99.5 ± 24.0 ms, p = 0.082). INTERPRETATION: Prolonged latency after anterior cruciate ligament injury may predict post-traumatic knee osteoarthritis 6-years after anterior cruciate ligament reconstruction. Latency may shorten with preoperative physical therapy, yet athletes still moved on to develop osteoarthritis. Quadriceps function may need intervention immediately following anterior cruciate ligament injury for prevention of post-traumatic knee osteoarthritis.

Individuals early after anterior cruciate ligament reconstruction show intact motor learning of step length via the split-belt treadmill.

BACKGROUND: Rupturing the anterior cruciate ligament is an orthopedic injury that results in neuromuscular impairments affecting sensory input to the central nervous system. Traditional physical therapy after anterior cruciate ligament reconstruction aims to rehabilitate orthopedic impairments but fails to address asymmetric gait mechanics that are present post-operatively and are linked to the development of post-traumatic osteoarthritis. A first step towards developing gait interventions is understanding if individuals after anterior cruciate ligament reconstruction have the capacity to learn new walking mechanics. METHODS: The split-belt treadmill offers a task-specific approach to examine neuromuscular adaptations in patients after injury. The potential for changing spatiotemporal gait mechanics via split-belt treadmill adaptation has not been tested early after anterior cruciate ligament reconstruction; nor has the ability to retain and transfer newly learned gait mechanics. Therefore, we used a split-belt treadmill paradigm to compare gait adaptation, retention, and transfer to overground walking between 15 individuals 3-9 months after anterior cruciate ligament reconstruction and 15 matched control individuals. FINDINGS: Results suggested individuals after anterior cruciate ligament reconstruction were able to adapt and retain step length symmetry changes as well as controls. There was also evidence of partial transfer to overground walking, similar to controls. INTERPRETATION: Despite disruption in afferent feedback from the joint, individuals early after anterior cruciate ligament reconstruction can learn a new gait pattern using sensorimotor adaptation, retain, and partially transfer the learned gait pattern. This may be a critical time to intervene with gait-specific interventions targeting post-operative gait asymmetries.

Individuals with a ventral hernia who report moderate to high fear have worse functional performance than those with low fear.

PURPOSE: Ventral hernia repairs (VHR) are performed to restore the integrity of the abdominal wall. Fear of movement, or kinesiophobia, may develop in patients with ventral hernia due to pain and functional impairments, however it has not yet been objectively measured in this patient population. The purpose of this study was to test the hypothesis that in patients with ventral hernia awaiting surgical repair, higher levels of kinesiophobia would be associated with poorer mobility, abdominal core function, and quality of life. METHODS: Seventy-seven participants scheduled for ventral hernia repair were enrolled as part of an ongoing randomized controlled trial (NCT05142618). The Tampa Scale of Kinesiophobia (TSK-11) is an 11-item questionnaire that asks about fear of movement and physical activity restriction. Participants were split into groups based on their TSK-11 score (minimal, low, moderate to high). Primary outcome measures included the five-time sit-to-stand (5xSTS), Quiet Unstable Sitting Test (QUeST), and the Hernia-Related Quality-of-Life (HerQLeS) survey. A one-way ANOVA with a Bonferroni correction compared QUeST, 5xSTS, and HerQLes results between groups. RESULTS: Groups were significantly different on 5xSTS (minimal: 11.4 ± 2.6 s, low: 13.8 ± 3.1 s, moderate to high: 17.8 ± 9.8 s; p = 0.001) and HerQLes (minimal: 58.0 ± 27.8, low: 49.4 ± 22.0, moderate to high: 30.6 ± 25.3; p = 0.003) but not QUeST (minimal: - 2.8 ± 2.5, low: - 6.8 ± 10.0, moderate to high: - 5.5 ± 5.0; p = 0.16). CONCLUSION: Individuals with moderate to high kinesiophobia have worse pre-operative performance-based (5xSTS) and self-reported (HerQLes) function and quality of life than those with minimal and low kinesiophobia. Future research should examine the influence of kinesiophobia on post-operative outcomes as it may be a potent target for rehabilitation.

Who's Afraid of Electrical Stimulation? Let's Revisit the Application of NMES at the Knee.

BACKGROUND: Restoring quadriceps strength is essential for successful rehabilitation of knee injuries, but many athletes return to their previous activity with persisting muscle weakness. Strong evidence supports using neuromuscular electrical stimulation (NMES) to improve quadriceps strength; however, there is a lack of widespread clinical implementation. We believe there is a critical need to provide clinical approaches that promote using NMES to improve patients' quadriceps strength and ensuring clinicians provide high-value rehabilitation care. CLINICAL QUESTION: What is best practice when using NMES to facilitate strength after injury, what are barriers to its use, and how can they be addressed? KEY RESULTS: We discuss the low clinical implementation of NMES, perceived barriers to using NMES, and provide recommendations for setup and dosage parameters for effective use of NMES. CLINICAL APPLICATION: We aim for this commentary, with accompanying videos, to serve as a resource for clinicians who are using commercially available NMES units in clinical practice. J Orthop Sports Phys Ther 2024;54(2):1-6. Epub 31 October 2023. doi:10.2519/jospt.2023.12028.

ABVENTURE-P pilot trial of physical therapy versus standard of care following ventral hernia repair: Protocol for a randomized controlled trial.

Hernia disease is one of the most common reasons patients seek surgical treatment, yet nearly 1 in 4 patients seeking ventral hernia repair in the United States suffer from chronic pain, disability, and diminished physical activity. The relationships between the anterior abdominal wall, lower back, diaphragm, and pelvic floor are critical in providing function and quality of life, yet management of hernia disease has been limited to surgical restoration of anatomy without taking into consideration the functional relationships of the abdominal core. Therefore, the primary goal of this study is to evaluate the feasibility of implementing physical therapy targeted to improving stability and function in this population. A secondary goal is to estimate whether pre-operative abdominal core function predicts responsiveness to physical therapy. This study is a registry-based randomized controlled trial (NCT05142618: Pilot Trial of Abdominal Core Rehabilitation To Improve Outcomes After Ventral Hernia Repair (ABVENTURE-P)). All participants will be randomized to one of two post-operative treatment arms: standard of care plus up to 16 sessions of physical therapy, or standard of care alone. Primary timepoints include pre-operative (baseline) and ten weeks after surgery, with intermediate or secondary timepoints 30 days, 6 months, and 1 year post-operative. At each timepoint, participants will undergo functional and patient-reported outcome testing. We will also collect data on retention rate and treatment adherence. An intention to treat approach is planned for all analyses, using all participants who were randomized and have available data at the 10-week timepoint. This is a pilot and feasibility trial, hence our goals are to establish safety and initial efficacy of the PT intervention, retention and adherence to both PT and control arms, whether pre-operative abdominal core function predicts responsiveness to PT, and to collect a large enough sample to power a future definitive multi-center randomized controlled trial.

Clinically Relevant Subgroups Among Athletes Who Have Ruptured Their Anterior Cruciate Ligaments: A Delaware-Oslo Cohort Study.

OBJECTIVE: To identify subgroups of individuals with anterior cruciate ligament (ACL) injuries based on patient characteristics, self-reported outcomes, and functional performance at baseline, and to associate subgroups with long-term outcomes after ACL rupture. METHODS: A total of 293 participants (45.7% male, mean ± SD age 26.2 ± 9.4 years, days from injury 58 ± 35) were enrolled after effusion, pain, and range of motion impairments were resolved and quadriceps strength was at least 70% of the uninvolved limb. Mixture modeling was used to uncover latent subgroups without a prior group classification using probabilistic assignment. Variables include demographics, functional testing, and self-reported outcome measures. Radiographic evidence of osteoarthritis (OA; i.e., Kellgren/Lawrence grade of ≥1) in the involved knee at 5 years after injury was the primary outcome of interest. Chi-square tests assessed differences in the presence of radiographic OA in the involved knee between subgroups at 5 years after ACL rupture. Secondary outcomes of interest included radiographic OA in the uninvolved knee, return to preinjury sport by 2 years, operative status, and clinical OA (classified using Luyten et al criteria) at 5 years. RESULTS: Four distinct subgroups exist after ACL rupture (younger good self-report, younger poor self-report, older poor self-report, older good self-report) with 30%, 31%, 47%, and 53%, respectively, having involved knee OA. The percentage of radiographic OA was not significantly different between the groups (P = 0.059). CONCLUSION: The prevalence of OA in all subgroups is highly concerning. These results suggest there are unique subgroupings of individuals that may guide treatment after ACL rupture and reconstruction by providing support for developing a patient-centered approach.

Markerless motion capture: What clinician-scientists need to know right now.

Markerless motion capture (mocap) could be the future of motion analysis. The purpose of this report was to describe our team of clinicians and scientists' exploration of markerless mocap (Theia 3D) and share data for others to explore (link: https://osf.io/6vh7z/?view_only=c0e00984e94a48f28c8d987a2127339d). Simultaneous mocap was performed using markerless and marker-based systems for walking, squatting, and forward hopping. Segment lengths were more variable between trials using markerless mocap compared to marker-based mocap. Sagittal plane angles were most comparable between systems at the knee joint followed by the ankle and hip. Frontal and transverse plane angles were not comparable between systems. The data collection experience using markerless mocap was simpler, faster, and user friendly. The ease of collection was in part offset by the added data transfer and processing times, and the lack of troubleshooting flexibility. If used selectively with proper understanding of limitations, markerless mocap can be exciting technology to advance the field of motion analysis.

Males and females have different muscle activity patterns during gait after ACL injury and reconstruction.

Kinematic and kinetic changes following anterior cruciate ligament (ACL) rupture and reconstruction (ACLR) have been fundamental to the understanding of mechanical disrupted load as it contributes to the development of posttraumatic osteoarthritis. These analyses overlook the potential contribution of muscle activity as it relates to the joint loading environment. Males and females classified as non-copers present with unique knee kinematics and kinetics after ACL injury. The purpose of this study was to perform sex-specific analyses in these individuals to explore muscle activity timing during gait after ACL rupture. Thirty-nine participants (12 females, 27 males) were enrolled. Muscle activity during gait was evaluated before and after pre-operative physical therapy, and six months after ACLR. Surface electromyography data were evaluated to determine timing (e.g., the time the muscle activity begins ('On') and ends ('Off')) for seven muscles: vastus lateralis and medialis (VL, VM), lateral and medial hamstrings (LH, MH), lateral and medial gastrocnemius (LG, MG), and soleus (SOL). General linear models with generalized estimating equations detected the effects of limb and time for muscle activity timing. Males presented with more limb asymmetries before and after pre-operative PT in the VL On (p < 0.001) and Off (p = 0.007), VM On and Off (p < 0.001), and MH off (p < 0.001), but all limb differences resolved by six months post ACLR. Changes in muscle activity in males were pervasive over time in both limbs. Females presented with no interlimb differences pre-operatively, and only involved limb VL off (p = 0.027) and VM off (p = 0.003) and the LH off in both limbs (p < 0.038) changed over time. Our data indicate that inter-limb differences in muscle activity across time points and changes in muscle activity timing over the course of physical therapy were sex specific. Males presented with more inter-limb differences in muscle activity across time points, and females presented with fewer asymmetries before and after pre-operative physical therapy. These data support that sex-specific adaptations should be taken into consideration when assessing biomechanical changes after ACLR.

Association of Quadriceps Strength Symmetry and Surgical Status With Clinical Osteoarthritis Five Years After Anterior Cruciate Ligament Rupture.

OBJECTIVE: The objective of this study was to examine the association of quadriceps strength symmetry and surgical status (anterior cruciate ligament [ACL] reconstruction or nonoperative management) with early clinical knee osteoarthritis (OA) 5 years after ACL injury or reconstruction. METHODS: In total, 204 of 300 athletes were analyzed 5 years after ACL injury or reconstruction. Quadriceps strength was measured and reported as a limb symmetry index. We identified participants with early clinical knee OA using the criteria that 2 of 4 Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales score ≤85%. We calculated odds ratios (ORs) and 95% confidence intervals (95% CIs) using logistic regression and adjusted for age, sex, meniscal injury, and body mass index to examine the associations of quadriceps strength and surgical status with clinical knee OA. RESULTS: In all, 21% of participants met the KOOS criteria for clinical knee OA. For every 1% increase in quadriceps limb symmetry index, there was a 4% lower odds of clinical OA (adjusted OR [ORadj ] 0.96 [95% CI 0.93-0.99]) at 5 years. Surgical status was not associated with clinical knee OA (ORadj 0.58 [95% CI 0.23-1.50]). CONCLUSION: More symmetric quadriceps strength, but not surgical status, 5 years after ACL injury or reconstruction was associated with lower odds of clinical knee OA.

Task-specific movement training improves kinematics and pain during the Y-balance test and hip muscle strength in females with patellofemoral pain.

OBJECTIVES: Task-specific movement training is a proposed intervention for patellofemoral pain aimed to optimise movement during daily tasks. Focused, progressive task practice emphasising optimal limb alignment may yield improvements in performance-based function and hip muscle strength, and transfer learnt movement patterns to untrained tasks. The purpose of this study was to determine if task-specific movement training improves performance-based function (composite score, movement, pain during movement) in an untrained task. Our secondary purpose was to test whether hip muscle strength improved following the movement training intervention. METHODS: This study was a secondary analysis of a prospective, non-randomised, within-group, double-baseline study. Twenty-three females with patellofemoral pain underwent task-specific movement training two times/week for 6 weeks. Outcomes were collected at three time points: enrolment (baseline), 6 weeks (preintervention) and 12 weeks (postintervention). A repeated measures analysis of variance tested whether the change during the intervention phase was greater than the change during the control phase. Y-balance composite score, hip and knee kinematics and pain during the Y-balance test were primary outcome measures; strength of the hip lateral rotator, abductor and extensor muscles was a secondary outcome measure. RESULTS: The change in composite score for the Y-balance test was not statistically significantly different between the intervention and control phases (p=0.16). The change during the intervention phase exceeded the change during the control phase for hip and knee kinematics and pain during the Y-balance test, with all variables improving (p<0.0001). The change during the intervention phase was greater than the control phase for hip muscle strength, with all variables improving (p<0.04). CONCLUSION: Although the Y-balance test composite score did not improve, performance-based function during an untrained task, measured by movement and pain during the test, improved following task-specific movement training. Hip muscle strength improved, despite no focused muscle strengthening. LEVEL OF EVIDENCE: Level II.

Patients Walking Faster After Anterior Cruciate Ligament Reconstruction Have More Gait Asymmetry.

BACKGROUND: Gait asymmetries after anterior cruciate ligament reconstruction (ACLR) may lead to radiographic knee osteoarthritis. Slower walking speeds have been associated with biomarkers suggesting cartilage breakdown. The relationship between walking speed and gait symmetry after ACLR is unknown. HYPOTHESIS/PURPOSE: To determine the relationship between self-selected walking speeds and gait symmetry in athletes after primary, unilateral ACLR. STUDY DESIGN: Secondary analysis of a clinical trial. METHODS: Athletes 24±8 weeks after primary ACLR walked at self-selected speeds as kinematics, kinetics, and electromyography data were collected. An EMG-driven musculoskeletal model was used to calculate peak medial compartment contact force (pMCCF). Variables of interest were peak knee flexion moment (pKFM) and angle (pKFA), knee flexion and extension (KEE) excursions, peak knee adduction moment (pKAM), and pMCCF. Univariate correlations were run for walking speed and each variable in the ACLR knee, contralateral knee, and interlimb difference (ILD). RESULTS: Weak to moderate positive correlations were observed for walking speed and all variables of interest in the contralateral knee (Pearson's r=.301-.505, p≤0.01). In the ACLR knee, weak positive correlations were observed for only pKFM (r=.280, p=0.02) and pKFA (r=.263, p=0.03). Weak negative correlations were found for ILDs in pKFM (r=-0.248, p=0.04), KEE (r=-.260, p=0.03), pKAM (r=-.323, p<0.01), and pMCCF (r=-.286, p=0.02). CONCLUSION: Those who walk faster after ACLR have more asymmetries, which are associated with the development of early OA. This data suggests that interventions that solely increase walking speed may accentuate gait symmetry in athletes early after ACLR. Gait-specific, unilateral, neuromuscular interventions for the ACLR knee may be needed to target gait asymmetries after ACLR. LEVEL OF EVIDENCE: III.

Quadriceps Strength Symmetry Does Not Modify Gait Mechanics After Anterior Cruciate Ligament Reconstruction, Rehabilitation, and Return-to-Sport Training.

BACKGROUND: After anterior cruciate ligament (ACL) reconstruction (ACLR), biomechanical asymmetries during gait are highly prevalent, persistent, and linked to posttraumatic knee osteoarthritis. Quadriceps strength is an important clinical measure associated with preoperative gait asymmetries and postoperative function and is a primary criterion for return-to-sport clearance. Evidence relating symmetry in quadriceps strength with gait biomechanics is limited to preoperative and early rehabilitation time points before return-to-sport training. PURPOSE/HYPOTHESIS: The purpose was to determine the relationship between symmetry in isometric quadriceps strength and gait biomechanics after return-to-sport training in athletes after ACLR. We hypothesized that as quadriceps strength symmetry increases, athletes will demonstrate more symmetric knee joint biomechanics, including tibiofemoral joint loading during gait. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Of 79 athletes enrolled in the ACL-SPORTS Trial, 76 were participants in this study after completing postoperative rehabilitation and 10 return-to-sport training sessions (mean ± SD, 7.1 ± 2.0 months after ACLR). All participants completed biomechanical walking gait analysis and isometric quadriceps strength assessment using an electromechanical dynamometer. Quadriceps strength was calculated using a limb symmetry index (involved limb value / uninvolved limb value × 100). The biomechanical variables of interest included peak knee flexion angle, peak knee internal extension moment, sagittal plane knee excursion at weight acceptance and midstance, quadriceps muscle force at peak knee flexion angle, and peak medial compartment contact force. Spearman rank correlation (ρ) coefficients were used to determine the relationship between limb symmetry indexes in quadriceps strength and each biomechanical variable; alpha was set to .05. RESULTS: Of the 76 participants, 27 (35%) demonstrated asymmetries in quadriceps strength, defined by quadriceps strength symmetry <90% (n = 23) or >110% (n = 4) (range, 56.9%-131.7%). For the biomechanical variables of interest, 67% demonstrated asymmetry in peak knee flexion angle; 68% and 83% in knee excursion during weight acceptance and midstance, respectively; 74% in internal peak knee extension moment; 57% in medial compartment contact force; and 74% in quadriceps muscle force. There were no significant correlations between quadriceps strength index and limb symmetry indexes for any biomechanical variable after return-to-sport training (P > .129). CONCLUSION: Among those who completed return-to-sport training after ACLR, subsequent quadriceps strength symmetry was not correlated with the persistent asymmetries in gait biomechanics. After a threshold of quadriceps strength is reached, restoring strength alone may not ameliorate gait asymmetries, and current clinical interventions and return-to-sport training may not adequately target gait.

Sex and mechanism of injury influence knee joint loading symmetry during gait 6 months after ACLR.

Early-onset knee osteoarthritis (OA) is associated with gait asymmetries after anterior cruciate ligament reconstruction (ACLR). Women have higher risks of sustaining non-contact injuries, and are more likely to present with aberrant movement patterns associated with the mechanism of injury (MOI). We hypothesized that sex and MOI would influence gait after ACLR. Seventy participants, grouped by sex and MOI, completed biomechanical testing during over-ground walking when they had full knee range of motion, trace or less knee effusion, greater than 80% quadriceps strength limb symmetry index, ability to hop on each leg without pain, and initiated running. Bilateral knee kinetics, kinematics, and joint contact forces were compared using mixed-model analysis of variance (α = .05). There was a three-way interaction effect of sex × MOI × limb for peak medial compartment contact force (P = .002), our primary outcome measure previously associated with OA development. Men with non-contact injuries walked with asymmetry characterized by underloading of the involved limb. Men with contact injuries walked with the most symmetrical loading. In women, no clear pattern emerged based on MOI. Targeting, and possibly prioritizing interventions for athletes who present with gait asymmetries after ACLR based on sex and MOI, may be necessary to optimize outcomes. Statement of Clinical Significance: Sex and MOI may influence walking mechanics, and could be considered in future interventions to target gait symmetry, as a response to interventions may vary based on differences in sex and MOI.

FUNCTIONAL MEASURES DO NOT DIFFER IN LATE STAGE REHABILITATION AFTER ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION ACCORDING TO MECHANISM OF INJURY.

BACKGROUND: Anterior cruciate ligament injuries are among the most common knee injuries. Mechanism of injury is classified as contact or non-contact. The majority of anterior cruciate ligament ruptures occur through a non-contact mechanism of injury. Non-contact anterior cruciate ligament ruptures are associated with biomechanical and neuromuscular risk factors that can predispose athletes to injuries and may impact future function. Non-contact mechanism of injury may be preceded by poor dynamic knee stability and therefore those with a non-contact mechanism of injury may be prone to poor dynamic knee stability post-operatively. Understanding how mechanism of injury affects post-operative functional recovery may have clinical implications on rehabilitation. PURPOSE: The purpose of this study was to determine if mechanism of injury influenced strength, functional performance, patient-reported outcome measures, and psychological outlook in athletes at four time points in the first two years following anterior cruciate ligament reconstruction. STUDY DESIGN: Secondary analysis of a clinical trial. METHODS: Seventy-nine athletes underwent functional testing at enrollment after impairment resolution. Quadriceps strength, hop testing, and patient-reported outcome measures were evaluated post-operatively at enrollment, following return-to-sport training and one year and two years after anterior cruciate ligament reconstruction. Participants were dichotomized by mechanism of injury (29 contact, 50 noncontact). Independent t-tests were used to compare differences between groups. RESULTS: There were no meaningful differences between contact and non-contact mechanism of injury in any variables at enrollment, post-training, one year, or two years after anterior cruciate ligament reconstruction. CONCLUSION: Function did not differ according to mechanism of injury during late stage rehabilitation or one or two years after anterior cruciate ligament reconstruction. LEVEL OF EVIDENCE: III.