Total Knee Arthroplasty Assessments Should Include Strength and Performance-Based Functional Tests to Complement Range-of-Motion and Patient-Reported Outcome Measures

Range of motion (ROM) and pain often define successful recovery after total knee arthroplasty (TKA), but these routine clinical outcomes correlate poorly or not at all to functional capacity after TKA. The purpose of this Perspective is to underscore the importance of muscle strength and performance-based functional tests in addition to knee ROM and patient-reported outcome (PRO) measures to evaluate outcomes after TKA. Specifically: (1) muscle strength is the rate-limiting step for recovery of function after TKA; (2) progressive rehabilitation targeting early quadriceps muscle strengthening improves outcomes and does not compromise ROM after TKA; (3) ROM and PROs fail to fully capture functional limitations after TKA; and (4) performance-based functional tests are critical to evaluate function objectively after TKA. This Perspective also addresses studies that question the need for or benefit of physical therapy after TKA because their conclusions focus only on ROM and PRO measures. Future research is needed to determine the optimal timing, delivery, intensity, and content of physical therapy

Gait Mechanics are Influenced by Quadriceps Strength, Age, and Sex after Total Knee Arthroplasty

Although most patients are satisfied with outcomes after total knee arthroplasty (TKA), many retain preoperative altered gait mechanics. Identifying patient characteristics associated with gait mechanics will improve rehabilitation strategies and enhance our understanding of movement disorders. Therefore, the purpose of this study was to identify which patient characteristics are related to gait mechanics in the surgical limb during walking post-TKA. Patient characteristics included age, body mass, sex, quadriceps strength, self-reported function, and knee pain. General linear regression was used to compare patient characteristics associated with gait mechanics, after controlling for gait speed, functional capacity and time from surgery. We tested 191 patients cross-sectionally at 6–24 months after primary, unilateral TKA. Quadriceps weakness in the surgical limb was associated with less peak vertical ground reaction force (PvGRF) (β = .245, p = .044), knee extension moment (β = .283, p = .049), and knee extension excursion (β = .298, p = .038). Older age (β = .168, p = .050) was associated with less PvGRF. Quadriceps strength in the nonsurgical limb (β = −.357, p = .021) was associated with greater knee extension excursion in the surgical limb. Females with TKA (β = −.276, p = .007) had less knee flexion excursion compared to males. Faster gait speed was also associated with greater PvGRF (β = .585, p \u3c .001), knee extensor moment (β = .481, p \u3c .001), and knee flexion excursion (β = .318, p \u3c .001). Statement of Clinical Significance: This study showed quadriceps weakness, slower gait speed, older age and being female were related to altered gait mechanics post-TKA. These findings will help clinicians better educate patients and develop targeted interventions for improving care in patients post-TKA

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 II

Prospective Telehealth Analysis of Functional Performance, Frailty, Quality of Life, and Mental Health after COVID-19 hospitalization

Background COVID-19 is a global pandemic with poorly understood long-term consequences. Determining the trajectory of recovery following COVID-19 hospitalization is critical for prioritizing care, allocating resources, facilitating prognosis, and informing rehabilitation. The purpose of this study was to prospectively evaluate recovery following COVID-19 hospitalization. Methods Participants age 18 years or older who were hospitalized for ≥24 h due to COVID-19 completed phone/video call virtual assessments (including the 10-time chair rise test) and survey forms at three time points (2–6, 12, and 18 weeks) after hospital discharge. Univariate logistic and linear regression models assessed the associations of the outcomes with primary predictors (categorical age, sex, race/ethnicity group, and categorical pre-hospitalization frailty) at baseline; the same were used to assess differences in change from week 2–6 (continuous outcomes) or outcome persistence/worsening (categorical) at last contact. Results One hundred nine adults (age 53.0 [standard deviation 13.1]; 53% female) participated including 43 (39%) age 60 or greater; 59% identified as an ethnic and/or racial minority. Over 18 weeks, the mean time to complete the 10-time chair rise test decreased (i.e., improved) by 6.0 s (95% CI: 4.1, 7.9 s; p \u3c 0.001); this change did not differ by pre-hospital frailty, race/ethnicity group, or sex, but those age ≥ 60 had greater improvement. At weeks 2–6, 67% of participants reported a worse Clinical Frailty Scale category compared to their pre-hospitalization level, whereas 42% reported a worse frailty score at 18 weeks. Participants who did not return to pre-hospitalization levels were more likely to be female, younger, and report a pre-hospitalization category of ‘very fit’ or ‘well’. Conclusions We found that functional performance improved from weeks 2–6 to 18 weeks of follow-up; that incident clinical frailty developed in some individuals following COVID-19; and that age, sex, race/ethnicity, and pre-hospitalization frailty status may impact recovery from COVID-19. Notably, individuals age 60 and older were more likely than those under age 45 years to return to their pre-hospitalization status and to make greater improvements in functional performance. The results of the present study provide insight into the trajectory of recovery among a representative cohort of individuals hospitalized due to COVID-19. Background Coronavirus disease (COVID)-19 is a global pandemic with poorly understood long-term consequences. Recent data suggest that even mild cases of COVID-19 can result in significant long-term morbidity [1]. Determining the trajectory of recovery in patients following COVID-19 hospitalization is critical for prioritizing care, allocating resources, facilitating prognosis, and informing rehabilitation

Walking mechanics, second injury, early osteoarthritis development, and functional outcomes after anterior cruciate ligament (ACT) reconstruction

Snyder-Mackler, LynnBuchanan, Thomas S.Anterior cruciate ligament (ACL) injury is extremely prevalent among active adolescents and young adults. ACL injury and ACL reconstruction (ACLR) dramatically increase an individual’s risk for poor outcomes, including second ACL rupture and early development of osteoarthritis (OA) when the individual is still a young adult. Aberrant movement patterns during walking may influence the risk for poor outcomes among individuals after ACLR. ☐ The long-term objective of this work is to improve functional outcomes and reduce second injury and early OA development after ACLR. This dissertation aimed to identify risk factors associated with second ACL injury (Aim 1) and early patellofemoral OA development (Aim 4), and to evaluate the effect of interventions (i.e., meniscus treatment and rehabilitation strategies) on a known risk factor for early tibiofemoral OA development (Aims 2 and 3) and functional outcomes (Aim 5). ☐ Individuals after primary, unilateral ACLR were recruited. Aims 1-3 and 5 were derived from the ACL-SPORTS clinical trial, which enrolled 80 athletes who were 3-9 months after ACLR. Aim 4 was derived from the Quantitative Magnetic Resonance Imaging (QMRI) and Biomechanical Modeling study, including participants 3 and 6 months after ACLR. All participants underwent detailed biomechanical motion analyses during walking. ACL-SPORTS participants also completed comprehensive clinical and functional evaluations, and QMRI participants also underwent sagittal QMRI analyses. For Aim 5, homogenous subsets of 2 previous “gold-standard” cohorts were used for comparison to the ACL-SPORTS cohort. ☐ The key findings of Aim 1 are that young female athletes after ACLR should delay their return to high-level sports even in the absence of gait impairments, strength deficits, and functional or clinical impairments. Aim 2 indicates that concomitant medial meniscus treatment at the time of ACLR influences walking mechanics and knee joint loading 6 months and 2 years after ACLR, potentially explaining the elevated risk for OA and informing future studies investigating tailored rehabilitation programs. Aim 3 suggests that return-to-sport training with and without perturbation training does not improve walking mechanics, but interlimb symmetry improves by 2 years after ACLR; future research should evaluate gait specific interventions. Aim 4 provides preliminary evidence of the association between walking mechanics and especially walking speed with cartilage degradation in the patellofemoral joint of individuals early after ACLR, a key preliminary step for reducing symptomatic OA. Finally, Aim 5 indicates that return-to-sport training leads to superior functional outcomes among young female athletes after ACLR. ☐ This dissertation work will guide physicians, rehabilitation specialists, and other healthcare professionals who rehabilitate the hundreds of thousands of individuals who tear their ACLs each year. This dissertation will help improve functional outcomes and reduce second ACL injury and early OA development and progression, lowering health-care costs and improving quality of life.Ph.D.University of Delaware, Biomechanics and Movement Science Progra

Identifying Gait Pathology after ACL Reconstruction Using Temporal Characteristics of Kinetics and Electromyography

Purpose Asymmetrical gait mechanics after anterior cruciate ligament reconstruction (ACLR) are associated with the development of posttraumatic knee osteoarthritis. Current measures of gait mechanics have focused heavily on peak magnitudes of knee kinematics, kinetics, and joint contact forces but have seldom considered the rate of knee loading, cumulative knee load, or the timing of motor input surrounding peaks. The purpose of this study was to introduce and describe novel metrics of gait using temporal characteristics of kinetics and EMG to identify neuromuscular deficits of the quadriceps in patients after ACLR. Methods Gait mechanics were assessed 6 months (n = 145) and 24 months (n = 116) after ACLR. External knee flexion rate of moment development (RMD) and knee flexion moment impulse (KFMI) leading up to the time of peak knee flexion moment (pKFM), peak RMD between initial contact to pKFM, and cumulative KFMI were calculated. Extensor latencies from the quadriceps, vastus medialis, vastus lateralis, and rectus femoris (time of pKFM – time of peak EMG activity) during the weight acceptance phase of gait were also calculated. Paired-sample t-tests (α = 0.05) were performed between limbs at both time points. Results Slower RMD, smaller KFMI, and longer extensor latencies in the involved compared with uninvolved limb were observed across all measures at 6 months (P \u3c 0.005). At 24 months, RMDpeak was slower, and KFMI50ms, KFMI100ms, and KFMItotal were lower in the involved limb (P \u3c 0.003), but no other asymmetries were found. Conclusions Slower RMD, smaller KFMI, and prolonged extensor latencies may characterize neuromuscular deficits underlying aberrant gait mechanics early after ACLR. RMD, KFMI, and extensor latencies during gait should be considered in the future to quantify asymmetrical movement patterns observed after ACLR and as markers of recovery

Association of the Psychological Response to the ACL-SPORTS Training Program and Self-reported Function at 2 Years After Anterior Cruciate Ligament Reconstruction

Background: Psychological readiness to return to sport has emerged as an important factor associated with outcomes after anterior cruciate ligament reconstruction (ACLR). Psychological factors are potentially modifiable during the course of rehabilitation, and improving them may lead to better outcomes. Purpose: To determine whether athletes with a positive psychological response after participation in a neuromuscular training and second injury prevention program had better self-reported function and activity outcomes compared with athletes who did not have a meaningful change. Study Design: Cohort study; Level of evidence, 3. Methods: After ACLR and the completion of formal rehabilitation, 66 level I/II athletes completed the following self-reported measures at enrollment (pretraining): the Anterior Cruciate Ligament–Return to Sport after Injury (ACL-RSI) scale, the International Knee Documentation Committee (IKDC) subjective knee form, and the 5 subscales of the Knee injury and Osteoarthritis Outcome Score (KOOS). Participants completed these measures after 10 sessions of agility, plyometric, and progressive strength training and at 1 and 2 years after ACLR. Participants who displayed an increase in the ACL-RSI score from pretraining to posttraining that exceeded the minimal clinically important difference (≥10 points) were defined as having a positive psychological response (responders) to training, and those who did not were defined as nonresponders. A mixed-model analysis of variance was used to determine if group differences in IKDC and KOOS scores existed over the 4 time points (pretraining, posttraining, and the 1- and 2-year follow-ups). Results: The responders reported better self-reported function compared with the nonresponders, regardless of time, on the IKDC form (P = .001), KOOS–Sport and Recreation (P = .014), KOOS-Pain (P = .007), and KOOS-Symptoms (P = .002) but not on the KOOS–Quality of Life (P = .078). Overall, 77% of responders and 67% of nonresponders returned to their previous level of sport by 1 year after ACLR (P = .358), and 82% of responders and 78% of nonresponders returned to their previous level of sport by 2 years after ACLR (P = .668). Conclusion: Ultimately, 59% of the athletes in this study displayed a meaningful improvement in their psychological outlook over the course of the training program. Responders demonstrated persistently better self-reported function at posttraining and at 1 and 2 years after ACLR, but there were no between-group differences in return-to-sport rates

Bone–Patellar Tendon–Bone Autograft Harvest Prolongs Extensor Latency during Gait 2 yr after ACLR

Purpose Bone–patellar tendon–bone (BPTB) graft harvest for anterior cruciate ligament reconstruction alters patellar tendon properties, which inflict poor quadriceps neuromuscular function. BPTB autografts are associated with higher rates of posttraumatic osteoarthritis, which in turn is associated with pathological gait. The purpose of this study was to investigate the latency between the time of peak quadriceps activity and the peak knee flexion moment during gait, between those with BPTB grafts (n = 23) and other graft types (hamstring autograft or allografts, n = 54), 5 ± 2 months and 2 yr (25 ± 3 months) after anterior cruciate ligament reconstruction. We hypothesized that longer latencies would be observed in the BPTB graft group in the involved limb. We expected latencies to shorten over time. Methods Knee moments and quadriceps EMG were collected during gait, and vastus medialis, vastus lateralis, rectus femoris (RF), and quadriceps latencies were calculated. Linear mixed-effects models were used to compare latencies between graft types and over the two time points. Results The main effects of graft type were observed for vastus medialis (P = 0.005) and quadriceps (P = 0.033) latencies with the BPTB graft group demonstrating longer latencies. No main effects of graft type were observed for vastus lateralis (P = 0.051) and RF (P = 0.080) latencies. Main effects of time were observed for RF latency (P = 0.022). Conclusions Our hypothesis that the BPTB graft group would demonstrate longer extensor latency was supported. Contrary to our second hypothesis, however, latency only improved in RF and regardless of graft type, indicating that neuromuscular deficits associated with BPTB grafts may persist 2 yr after surgery. Persistent deficits may be mediated by changes in the patellar tendon’s mechanical properties. Graft-specific rehabilitation may be warranted to address the long-term neuromechanical deficits that are present after BPTB graft harvest

Gait mechanics are influenced by quadriceps strength, age, and sex after total knee arthroplasty

Although most patients are satisfied with outcomes after total knee arthroplasty (TKA), many retain preoperativealteredgait mechanics. Identifying patient characteristics associated with gait mechanics will improve rehabilitation strategies and enhance our understanding of movement disorders. Therefore, the purpose of this study was to identify which patient characteristicsare related to gait mechanics in the surgical limbduring walking post-TKA.Patient characteristicsincluded age, body mass, sex, quadriceps strength, self-reported function and knee pain. General linear regressionwas used to compare patient characteristicsassociated with gait mechanics, after controlling for gait speed, functional capacity and time from surgery.We tested 191 patients cross-sectionally at 6 to 24 monthsafter primary, unilateral TKA.Quadriceps weakness in the surgical limb was associated with less peakvertical ground reaction force (PvGRF) (β=0.245, p=0.044), knee extension moment(β=0.283, p=0.049) andknee extension excursion (β=0.298, p=0.038). Older age (β=0.168, p=0.050) was associated with less PvGRF.Quadriceps strength in the non-surgical limb (β=−0.357,p=0.021) was associated with greater knee extension excursion in the surgical limb. Females with TKA (β=−0. 276, p=0.007) had less knee flexion excursion compared to males.Faster gait speed was also associated with greater PvGRF (β=0.585, p<0.001), knee extensor moment (β=0.481, p<0.001) and knee flexion excursion (β=0.318, p<0.001). STATEMENT OF CLINICAL SIGNIFICANCE: This study showedquadriceps weakness, slower gait speed, older age and beingfemalewere related to altered gait mechanics post-TKA. These findingswill help clinicians better educatepatients and develop targeted interventions for improving care in patients post-TKA

Knee Joint Biomechanics During Gait Improve from 3 to 6 Months after Anterior Cruciate Ligament Reconstruction

Gait alterations after anterior cruciate ligament reconstruction (ACLR) are commonly reported and have been linked to posttraumatic osteoarthritis development. While knee gait alterations have been studied at several time points after ACLR, little is known about how these biomechanical variables change earlier than 6 months after surgery, nor is much known about how they differ over the entire stance phase of gait. The purpose of this study was to examine knee gait biomechanical variables over their entire movement pattern through stance at both 3 and 6 months after ACLR and to study the progression of interlimb asymmetry between the two postoperative time points. Thirty‐five individuals underwent motion analysis during overground walking 3 (3.2 ± 0.5) and 6 (6.4 ± 0.7) months after ACLR. Knee biomechanical variables were compared between limbs and across time points through 100% of stance using statistical parametric mapping; this included a 2 × 2 (Limb × Time) repeated measures analysis of variance and two‐tailed t‐tests. Smaller knee joint angles, moments, extensor forces, and medial compartment forces were present in the involved versus uninvolved limb. Interlimb asymmetries were present at both time points but were less prevalent at 6 months. The uninvolved limb\u27s biomechanical variables stayed relatively consistent over time, while the involved limb\u27s trended toward that of the uninvolved limb. Statement of Clinical Significance: Interventions to correct asymmetrical gait patterns after ACLR may need to occur early after surgery and may need to focus on multiple parts of stance phase