Isokinetic Quadriceps Strength Research Articles

Revision Anterior Cruciate Ligament Reconstruction with the All-Soft Tissue Quadriceps Tendon Autograft Has Acceptable Early and Intermediate-Term Outcomes

The purposes were to (1) examine early to intermediate-term clinical outcomes and complications of revision anterior cruciate ligament reconstruction (ACLR) using all-soft tissue quadriceps tendon (QT) autografts, and (2) compare quadriceps strength between patients who had hamstring versus patella tendon autografts in their previous reconstruction. One hundred patients (52 males/48 females; 22.6 ± 8.0 years) undergoing revision ACLR with all-soft tissue QT autografts were prospectively followed. All revision procedures were performed by a single surgeon, using a minimally invasive graft harvest technique and suspensory fixation. Subjective assessment of knee function was obtained before and after surgery with the International Knee Documentation Committee (IKDC) survey. Postoperative knee laxity and isokinetic quadriceps strength were collected at regular intervals. Strength was reported as limb symmetry index (LSI; surgical side divided by nonsurgical side). Complications including hematomas, postoperative loss of knee extension, and graft failures were recorded. To determine clinical significance (P ≤ .05), outcomes were compared using analysis of variance or paired samples t-tests. The mean IKDC scores significantly improved (54.3 ± 13.0 vs 82.8± 13.8), with an average follow-up of 42.2 ± 21.2 months. There were no significant changes in knee laxity side-to-side differences: 6 weeks (1.2 ± 1.5 mm), 3 months (1.2 ± 1.8 mm), 6 months (1.4 ± 1.6 mm). Quadriceps LSIs significantly improved from 71.6% ± 19.3% at 6 months to 81.5% ± 19.3% at 12 months for 60°/s isokinetic testing and 76.6% ± 16.4% at 6 months to 83.9% ± 16.9% at 12 months for 180°/s testing. Graft harvest site hematomas developed in 2 patients, postoperative loss of knee extension in 4 patients, and graft failure in 11 patients. No significant differences in quadriceps or hamstrings LSIs were noted between patients with previous hamstring versus patella tendon autografts (P>.050). Revision ACLR with all-soft tissue QT autografts has acceptable early and intermediate-term outcomes with reasonable complication rates (11/80 patients with follow-up). Secondary insult to the extensor mechanism via QT autograft harvest does not adversely affect strength after prior patellar tendon versus hamstring autograft. Level IV, cases series subgroup analysis.

Specific Contribution of Quadriceps Muscle Strength, Endurance, and Power to Functional Exercise Capacity in People With Chronic Obstructive Pulmonary Disease: A Multicenter Study

Various functional muscle properties affect different aspects of functional exercise capacity in people with chronic obstructive pulmonary disease (COPD). The purpose of this study was to investigate the contribution of quadriceps muscle strength, endurance, and power to 6-Minute Walking Distance (6MWD) and 1-minute sit-to-stand test (1STS) performance in people with COPD. The study was a prospective, multicenter, cross-sectional study. Anthropometrics, Medical Research Council dyspnea scale, lung function, 6MWD, and 1STS number of repetitions were assessed. Isometric quadriceps strength and endurance, isotonic quadriceps endurance, isokinetic quadriceps strength, and power were assessed on a computerized dynamometer while functional quadriceps power was determined during 5 sit-to-stand repetitions. Univariate and multivariate analyses were performed to determine the contribution of functional muscle properties to the 6MWD and the 1STS number of repetitions. The study included 70 people with COPD (mean % predicted forced expiratory volume in 1 second=58.9 [SD=18.2]). The 6MWD correlated with each functional muscle property except the isometric quadriceps endurance. The number of repetitions during the 1STS correlated with each functional muscle property except isometric measurements. Multivariate models explained 60% and 39% of the variance in the 6MWD and 1STS number of repetitions, respectively, with quadriceps power determined during 5 sit-to-stand repetitions being the muscle functional property with the strongest contribution to the models. Except for isometric endurance, quadriceps strength, endurance, and power were associated with functional exercise capacity in people with moderate COPD. Among these functional muscle properties, muscle power contributed the most to the 6MWD and 1STS number of repetitions, suggesting that muscle power is more relevant to functional exercise capacity than muscle strength or endurance in people with COPD. Understanding the individual contribution of muscle properties to functional status is important to designing interventions. This study provides the guidance that muscle power may be more important to functional exercise capacity than muscle strength or endurance in people with COPD.

TIMELINE OF GAINS IN QUADRICEPS STRENGTH SYMMETRY AND PATIENT-REPORTED FUNCTION EARLY AFTER ACL RECONSTRUCTION.

Quadriceps weakness is a predictor of long-term knee function and strength recovery can vary from months to years after anterior cruciate ligament reconstruction (ACLR). However, few studies evaluate quadriceps strength and self-reported function within the first several weeks after ACLR. To examine changes over time in quadriceps strength symmetry, quadriceps peak torque, and self-reported knee function prior to and at six, 12, and 24 weeks post-ACLR. The hypotheses were 1) quadriceps strength symmetry, bilateral quadriceps peak torque, and patient-reported function would improve over time from pre-ACLR to 24 weeks post-ACLR and 2) significant improvements in patient-reported function, but not strength symmetry, would occur between time points. Prospective, cohort study. Thirty participants completed four testing sessions: pre-surgery and six, 12, and 24 weeks post-ACLR. Isometric quadriceps strength testing was performed at six weeks and isokinetic quadriceps strength was measured at all other testing points. Quadriceps index was calculated to evaluate between limb quadriceps strength symmetry. The Knee injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC) were administered at each time point. A repeated-measures analysis of variance evaluated changes over time, with post-hoc comparisons to determine at which time-point significant changes occurred. Quadriceps strength symmetry, involved limb quadriceps peak torque and all patient-reported outcome scores increased over time (p<0.02). Post-hoc tests showed that neither self-reported outcomes, nor quadriceps index improved between pre-surgery and six-weeks post-ACLR. From six to 12 weeks post-ACLR, scores on IKDC and KOOS Pain, Symptoms, Quality of Life, and Sport subscales improved (p≤0.003). From 12 to 24 weeks post-ACLR, quadriceps strength symmetry, involved limb quadriceps peak torque, KOOS-Symptoms, Quality of Life, and Sport subscales and the IKDC improved (p≤0.01). Uninvolved limb quadriceps peak torque did not change across any time point (p≥0.18). Patient-reported knee function increased between six and 24 weeks post-ACLR, while increases in involved limb quadriceps strength and quadriceps strength symmetry were not noted until 12-24 weeks post-ACLR. 2b, individual cohort study.

Who Passes Return-to-Sport Tests, and Which Tests Are Most Strongly Associated With Return to Play After Anterior Cruciate Ligament Reconstruction?

Background:Return-to-sport (RTS) testing after anterior cruciate ligament (ACL) reconstruction (ACLR) surgery has become popular. It has been recommended that such testing should incorporate several domains, or set of tests, but it is unclear which are most associated with a successful RTS.Purpose:To determine (1) the proportion of patients who can pass a set of self-report and functional tests at 6 months after ACLR; (2) age, sex, and activity level differences between patients who pass and those who do not; and (3) whether specific types of tests are associated with a return to competitive sport at 12 months.Study Design:Cohort study; Level of evidence, 2.Methods:This was a prospective longitudinal study of 450 patients who had primary ACLR. At 6 months postoperatively, patients completed 2 self-report measures, the International Knee Documentation Committee (IKDC) subjective knee form and ACL–Return to Sport after Injury (ACL-RSI) scale, and 3 functional measures: single hop and triple crossover hop for distance and isokinetic quadriceps strength. Limb symmetry index scores of ≥90 for functional tests, IKDC scores ≥85, and ACL-RSI scores ≥65 were considered indicators of satisfactory recovery. Proportional statistics and contingency analysis were used to determine associations between age, sex, preinjury sports level, and (1) meeting test thresholds and (2) RTS at 12 months.Results:Only 17 (3.8%) patients met all 5 test criteria at 6 months, and 95 (21%) patients did not pass any test. More of the younger patients (<21 years) passed all of the functional tests (P < .01), and more male patients met the IKDC threshold (P = .03). Patients who played level I sports before injury had the same pass rates as those who played level II/III sports. Patients who passed the thresholds for the ACL-RSI and IKDC scales had 4 and 3 times the odds, respectively, of RTS at 12 months (both P < .0001). Meeting the threshold for quadriceps strength or either of the hop tests at 6 months was not associated with RTS.Conclusion:At 6 months after ACLR, few patients met all of the thresholds of the common tests used to assess RTS ability, although younger patients had higher rates of passing the functional tests. Self-perceived symptoms/function and psychological readiness were associated with a return at 12 months.

INCORPORATING WORKLOAD MEASURES INTO REHABILITATION AFTER ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION: A CASE REPORT.

and purpose: Second anterior cruciate ligament (ACL) injury rates continue to be high, with a majority of injuries occurring soon after return-to-play, potentially because athletes may not be ready for the external load demands of the sport. Load metrics, tracked through wearable technology, may provide complementary information to standard limb symmetry indices in the return-to-play decision making process. The purpose of this case report was to quantify and monitor load using innovative technology during physical therapy rehabilitation after ACL reconstruction (ACLr) and compare to normative sport participation data.Case Description: The subject was a 12-year-old female soccer player that suffered an ACL injury followed by surgical reconstruction with a hamstring autograft and standard rehabilitation. Single-leg hop performance, isokinetic strength, and external loads (using wearable technology) were measured longitudinally during rehabilitation and analyzed at the time of return-to-play.Outcomes: The subject successfully achieved >90% LSI for isometric quadriceps strength (week 14), single leg hop battery (week 23), and isokinetic hamstrings (week 26) and quadriceps (week 31) strength by the time of return-to-play (week 39). At the time of return to play, external load metrics indicated that the subject's most intense rehabilitation session consisted of 36% less frequent movements, 38% lower total distances, and activity durations that were 29% lower than the expected demands of a match. Standard rehabilitation may underload patients relative to required sport demands. Measuring external load during the rehabilitation period may help clinicians adequately progress workload to the necessary demands of the patient's sport. With the current emphasis on restoring limb symmetry, clinicians may need to shift focus towards load preparation when returning a patient to their sport.Level of Evidence: 4Keywords: anterior cruciate ligament, load, rehabilitation, return to play, step count, movement system.

ACL reconstruction using a quadruple semitendinosus graft with cortical fixations gives suitable isokinetic and clinical outcomes after 2years.

The objective of this single-center randomized single-blinded trial was to assess the hypothesis that anterior cruciate ligament reconstruction (ACLR) using a four-strand semitendinosus (ST) graft with adjustable femoral and tibial cortical fixation produced good outcomes compared to an ST/gracilis (ST/G) graft with femoral pin transfixation and tibial bioscrew fixation. Follow-up was 2years. Patients older than 16years who underwent primary isolated ACLR included for 1year until August 2017 were eligible. The primary outcome measures were the subjective International Knee Documentation Committee (IKDC) score, isokinetic muscle strength recovery, and return to work within 2years. The study was approved by the ethics committee. Of 66 eligible patients, 60 completed the study and were included, 33 in the 4ST group and 27 in the ST/G group. Mean age was 30.5 ± 8.9years in the 4ST group and 30.3 ± 8.5 in the ST/G group (n.s.). No significant between-group differences were found for mean postoperative subjective IKDC (4ST group, 80.2 ± 12.5; ST/G group, 83.6 ± 13.6; n.s.), side-to-side percentage deficits in isokinetic hamstring strength (at 60°/s: ST group, 17% ± 16%; ST/G group, 14% ± 11%; n.s.) or quadriceps strength (at 60°/s: ST group, 14% ± 12%; ST/G group, 19% ± 17%; n.s.), return to work, pain during physical activities, side-to-side differential laxity, balance, loss of flexion/extension, or surgical complications. This trial demonstrates that functional outcomes after 4ST for ACLR with cortical fixations could be as good, although not better, than those obtained using ST/G. The 4ST technique spares the gracilis tendon, which thus preserves the medial sided muscle and thereby could improve function and limit donor-side morbidity. Level I.

Quantifying The Relationship Between Quadriceps Strength And Aerobic Fitness Following Acl Reconstruction

PURPOSE: Investigate the relationship between performance measures and quadriceps strength in individuals with ACL reconstruction (ACLR) and healthy controls. METHODS: Thirty-three individuals with ACLR (22F/11M, 19.9±2.2 years, 68.3±10.9 kg, 170.4±8.4 cm, 22.7±23.3 months post-surgery) and 29 healthy individuals (18F/11M, 20.1±1.5 years, 70.0±9.9 kg, 172.7±8.7 cm) completed isokinetic quadriceps strength testing using a Biodex dynamometer at 180 degrees/sec on both legs then completed vertical jump (VJ) testing with and without countermovement (NCMJ) on a jump mat. All participants completed an incremental treadmill test to determine maximal oxygen consumption testing (VO2max). Initial running velocity was self-selected and increased 0.5mph every 2 minutes until volitional fatigue. Knee extensor torques and VO2max were normalized by mass. Bivariate Pearson’s correlations were calculated between strength and performance variables. Significant correlations were retained for a regression analysis. RESULTS: In ACLR, peak torque was correlated with VJ (r = 0.43, P = .012), NCMJ (r = 0.44, P = .011), and VO2max (r = 0.52, P = .002). The only variable retained in the regression model was VO2max, which explained 26.7% of the variance in strength. In healthy individuals, peak torque was correlated with VJ (r = 0.72, P < .001), NCMJ (r = 0.62, P < .001), and VO2max (r = 0.55, P = .002). Two variables were retained in the regression model, including VJ (R2 = 52.2%) and VO2max (R2 = 6.8%) which together explained 59.0% of the variance in strength. CONCLUSIONS: Quadriceps strength was associated with a VJ, a powerful quadriceps movement, in healthy individuals, while strength in individuals with ACLR was associated with aerobic fitness. Although VO2max was a significant predictor of strength after ACLR, it explained a small amount of variance which suggests other factors contribute to strength after ACLR.

Who passes return to sport tests and which tests are most associated with a return to play after anterior cruciate ligament reconstruction?

Objectives:Although return to sport (RTS) testing has become popular following anterior cruciate ligament (ACL) reconstruction surgery, its utility is still questioned. The purpose of this study was to determine if there are age, sex and activity level differences between patients who pass a battery of self-report and functional tests at 6 months following surgery and to determine which tests are associated with a return to competition sport at 12 months.Methods:This was a prospective longitudinal study in which 450 patients who had undergone a primary ACL reconstruction were assessed at 6- and 12-months following surgery. Patients with a prior contralateral ACL injury, or who did not regularly participate in sport prior to injury were not included. There were 176 females and 274 males with a mean age of 25 (SD = 4) years. Six return to sport tests were conducted at 6 months and included two patient self-report measures: IKDC subjective knee form to measure symptoms and function and the ACL-RSI scale to measure psychological readiness to RTS; and four functional measures: single and triple hop for distance and isokinetic quadriceps strength measured at 60 and 180 deg/sec. Limb symmetry index scores of ≥90 for functional tests and IKDC scores of ≥85 and ACL-RSI scores ≥65 were considered indicators of satisfactory recovery. Proportional statistics and contingency analysis were used to determine associations between age (<21 vs. ≥21 years), sex, sport level (Level I vs. Levels II/III sports) and meeting test criteria and return to sport.Results:Only 13 (3%) patients met all 6 of the test criteria at 6 months following ACL reconstruction surgery and 83 (18%) patients did not pass any of the tests. A significantly greater proportion of younger patients passed all the functional tests (p<0.01). A greater proportion of males passed the IKDC threshold for symptoms and function (30% vs. 21% p=0.03) but there were no other sex differences. Patients who had played Level I sports before injury had the same pass rates as those who played Level II or III sports. Patients who passed the threshold for the IKDC and ACL-RSI scales had 4 (95% CI 3-6) times the odds of returning to competition sport at 12 months (p<0.0001). Conversely, meeting the threshold for either quadriceps strength test or either hop test at 6 months was not associated with a return to sport at 12 months.Conclusion:Few patients pass all the thresholds of common tests which are used to assess the ability to return to sport at 6 months following ACL reconstruction surgery although younger patients have higher rates of passing functional tests. This has implications for the utility of such testing and when patients should be cleared to return to sport. Patients may base their decision to return to sport on self-perceived symptoms and psychological readiness more than physical performance and muscle strength. These findings have implications for how return to sport testing may be used to facilitate a return to sport following this surgery.

The Effect of Water Exercise Therapy Given to Patients With Rheumatoid Arthritis

It is well known that patients suffering from rheumatoid arthritis have a reduced muscular function. The positive effect of physical training on rheumatic patients has been shown. In this study the effect of exercise therapy performed in a heated swimming pool has been evaluated for eight patients in a non-acute stage of rheumatoid arthritis. The median pre-treatment maximal isometric and isokinetic quadriceps strength was 88 Nm (44-146) and 99 Nm (62-149) respectively, which was 61% and 70% of that found in a control group of healthy persons. After 2 months exercise therapy the median maximal isometric and isokinetic quadriceps strength increased by 38% and 16% compared to the pre-treatment value (p less than 0.02 and p less than 0.05). All patients, except one who developed cardiac arrhythmia during the second test, accomplished a submaximal bicycle test (a.m. Astrand). An increase in the aerobic capacity was observed in all patients after the training period.

Perioperative and Postoperative Factors Influence Quadriceps Atrophy and Strength After ACL Reconstruction: A Systematic Review.

Background:Quadriceps dysfunction after anterior cruciate ligament (ACL) reconstruction is common and may affect return to sport due to resulting muscle atrophy and muscle weakness.Purpose:To systematically review the available literature regarding the impact of perioperative and postoperative interventions on quadriceps atrophy and loss of strength after ACL reconstruction.Study Design:Systematic review; Level of evidence, 3.Methods:A systematic review was performed in accordance with the 2009 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using PubMed, CINAHL, Cochrane Central, and Embase. The quality of evidence was evaluated using the Modified Coleman Methodology Score to determine consensus scores. Eligible level 1 or level 2 studies included interventions of perioperative nerve block, intraoperative tourniquet use, postoperative nutritional supplementation, and postoperative blood flow restriction training. Additionally, the included studies quantified postoperative quadriceps measurements such as thigh circumference, quadriceps cross-sectional area (CSA), isokinetic quadriceps strength, and/or quadriceps electromyographic (EMG) testing.Results:In total, 15 studies met stated inclusion and exclusion criteria with the following intervention types: perioperative nerve block (n = 4), intraoperative tourniquet use (n = 5), postoperative nutritional supplementation (n = 3), and postoperative blood flow restriction (n = 3). Intraoperative tourniquet use resulted in decreased thigh circumference and detrimental EMG changes in quadriceps function in 3 of the 5 included studies. Perioperative femoral nerve blocks were associated with transient decreases in postoperative quadriceps strength, persisting up to 6 weeks after surgery, in 2 of the 4 studies. Postoperative blood flow restriction training augmented quadriceps size and function after ACL reconstruction in 2 of 3 studies. Postoperative nutritional supplementation was associated with increased quadriceps volume and strength in 1 of the 3 studies examined.Conclusion:The peri- and postoperative factors reviewed here may influence quadriceps atrophy and strength after ACL reconstruction. Our results tentatively indicated that blood flow restriction training may be beneficial to the quadriceps after ACL reconstruction and that intraoperative tourniquet use and nerve block administration may be detrimental; however, the strongest finding was that all of these interventions would benefit from further level 1 and 2 evidence studies, including multicenter, randomized controlled trials with extended follow-up, to definitively determine their impact on return to activity.

Influence of Patient Demographics and Surgical Characteristics on Pass Rates of Return-to-Activity Tests in Anterior Cruciate Ligament-Reconstructed Patients Before Physician Clearance.

To identify the frequency of passing return-to-activity tests after anterior cruciate ligament reconstruction (ACLR) and to investigate the influence of patient-specific factors on pass rates. We hypothesized that isolated strength tests would be most difficult to pass and that graft type would be the most influential factor. Cross-sectional. Laboratory. Eighty patients with a history of primary, unilateral ACLR, and 80 healthy controls participated. Bilateral isokinetic strength, isometric strength, and single-leg hop tests were recorded during a single visit. The International Knee Documentation Committee (IKDC) Subjective Knee Evaluation measured subjective knee function, and the Tegner Activity Scale measured physical activity level. Pass rates were calculated for 3 thresholds of absolute between-limb asymmetry: 0% to 10%, 11% to 15%, and 16% to 20%. Pass rates were compared by sex (male and female), graft type (patellar and hamstrings), meniscal procedure (yes and no), physical activity level (</≥ median Tegner), and time from surgery (</≥ 6 months). Isokinetic quadriceps strength was consistently most difficult to pass, whereas the 6-meter timed hop and crossover hop tests were easiest. Graft type had the greatest influence on pass rates (isometric quadriceps and hamstring strength, hamstrings-to-quadriceps ratio), followed by time from surgery (6-meter timed hop and crossover hop), physical activity (IKDC), and meniscal procedure (6-meter timed hop). Isokinetic quadriceps strength was the most difficult test to pass, and single-leg hop tests were the easiest. Patient-specific factors including graft type, time from surgery, physical activity level, and meniscal procedure may influence the ability to meet return-to-activity criterion after ACLR.

Association between electromyographic localized muscle fatigue of the rectus femoris and static postural balance in physically active adult men

Abstract Although the determinant impact of exercise-induced muscle fatigue prior to postural balance assessment has been widely described, recent evidence suggests that hyperventilation and sensorimotor losses, rather than muscle fatigue, are responsible for the changes observed in postural balance. However, the association between localized muscle fatigue (LMF), induced by isokinetic dynamometer protocol test and assessed through surface electromyography, and postural balance in adults is poorly understood. We aimed to evaluate the association between the LMF of the rectus femoris and static postural balance in 51 adult men (43±14.8 years; 26.9±5 kg/m2). We obtained physical activity level and postural balance, respectively, through a triaxial accelerometry and a force platform. The quadriceps femoris strength and endurance were obtained using an isokinetic dynamometer and surface electromyography simultaneously. The association between the isokinetic and electromyographic LMF and static postural balance was investigated using linear regression models adjusted for age, body mass index, and isokinetic quadriceps strength and LMF. The correlations between postural balance variables and isokinetic muscle strength and LMF were weak-to-moderate. After multivariate analyses, we observed that electromyographic LMF were a predictor of postural balance, mainly of the mean amplitude and COP area and velocity in the mediolateral direction, regardless of isokinetic variables. Therefore, LMF plays a determinant role in the postural balance of physically active adult men. Fatigue indices are significant predictors of postural balance, regardless of previous fatigue induction.

Return to Sport Tests' Prognostic Value for Reinjury Risk after Anterior Cruciate Ligament Reconstruction: A Systematic Review.

Return to sports (RTS) clearance after anterior cruciate ligament (ACL) reconstruction typically includes multiple assessments. The ability of these tests to assess the risk of a reinjury remains unknown. To assess and rate RTS self-reported function and functional tests on prognostic value for reinjury risk after ACL reconstruction and RTS. Systematic review on level 2 studies. PubMed, Web of Knowledge, Cochrane Library, and Google Scholar databases were searched for articles published before March 2018. Original articles in English or German that examined reinjury risks/rates after primary (index) ACL injury, ACL reconstruction, and RTS were included. All RTS functional tests used in the included studies were analyzed by retrieving an effect size with predictive value (odds ratio, relative risk (risk ratio), positive predictive value, positive likelihood ratio, or hazard rate). A total of 276 potential studies were found; eight studies (moderate to high quality) on 6140 patients were included in the final analysis. The reinjury incidence recorded in the included studies ranged from 1.5% to 37.5%. Four studies reported a combination of isokinetic quadriceps strength at different velocities and a number of hop tests as predictive with various effect sizes. One reported isokinetic hamstring to quadriceps ratio (hazard rate = 10.6) as predictive. Two studies reported functional questionnaires (knee injury and osteoarthritis outcome score and Tampa Scale of Kinesiophobia-11; RR = 3.7-13) and one study showed that kinetic and kinematic measures during drop vertical jumps were predictive (odds ratio, 2.3-8.4) for reinjury and/or future revision surgery. Based on level 2 evidence, passing a combination of functional tests with predetermined cutoff points used as RTS criteria is associated with reduced reinjury rates. A combination of isokinetic strength and hop tests is recommended during RTS testing.

Impact of mild-to-moderate exacerbations on outcomes of neuromuscular electrical stimulation (NMES) in patients with COPD.

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are common among patients attending pulmonary rehabilitation (PR) and may compromise its outcomes. Neuromuscular electrical stimulation (NMES) seems one of the few exercise modalities that can actually be continued during AECOPD, due to its low burden on the impaired respiratory and cardiovascular system. However, the quality of evidence is low. The purpose of this study was to assess the impact of mild-to-moderate AECOPD on adherence/outcomes of a high-frequency (HF) or low-frequency (LF) NMES training program, as part of inpatient PR, in severely dyspneic, weakened individuals with COPD. 62 patients who received NMES as the sole supervised muscle training modality during an 8-week PR program (HF-NMES: n=33; LF-NMES: n=29) were analyzed retrospectively. 48.4% experienced ≥1 AECOPD during PR and were classified as exacerbators. Exacerbators completed 75 NMES sessions (interquartile range: 73-78) and were able to increase training intensity with 24mA (15-39), while non-exacerbators completed 76 sessions (73-79) and increased training intensity with 35mA (22-50), with no between-group differences (p=0.474 and p=0.065, respectively). The median change in 6-min walking distance, cycle endurance time, and isokinetic quadriceps strength and endurance did not differ between the exacerbation and non-exacerbation group. To conclude, the occurrence of mild-to-moderate AECOPD during a PR program primarily focused on NMES, does not affect adherence, intensity, and clinical outcomes in patients with severe COPD. Continuing NMES seems a feasible way to potentially counteract exacerbation-related lower-limb muscle dysfunction and improve outcomes of PR, with HF-NMES being the preferential muscle training modality.

Protracted Cardiovascular Impairments After Anterior Cruciate Ligament Injury: A Critically Appraised Topic.

Clinical Scenario: Anterior cruciate ligament (ACL) tear is a devastating knee injury with negative long-term consequences, such as early-onset knee osteoarthritis, biomechanical compensations, and reduced physical activity. Significant reduction in physical activity is a powerful indicator of cardiovascular (CV) disease; therefore, those with a history of ACL injury may be at increased risk for CV disease compared with noninjured individuals. Focused Clinical Question: Do individuals with a history of ACL injury demonstrate negative CV changes compared with those without a history of ACL injury? Summary of Key Findings: Three articles met the inclusion criteria and investigated CV changes after ACL injury. Both cross-sectional studies compared participants with ACL injury with matched controls. Bell etal compared time spent in moderate to vigorous physical activity and step count, whereas Almeida etal compared maximum rate of oxygen consumption, ventilatory thresholds, isokinetic quadriceps strength, and body composition. Collectively, both quantitative studies found that individuals with a history of ACL injury had less efficient CV systems compared with matched controls and/or preoperative data. Finally, a qualitative study of 3506 retired National Football League athletes showed an increased rate of arthritis and knee replacement surgery after an ACL injury when compared with other retired National Football League members, in addition to a >50% increased rate of myocardial infarction. Clinical Bottom Line: A history of ACL injury is a source of impaired physical activity. Preliminary data indicate that these physical activity limitations negatively impair the CV system, and individuals with a history of ACL injury demonstrate lower maximum oxygen consumption, self-reported disability, and daily step count compared with noninjured peers. These complications support the need for greater emphasis on CV wellness. Strength of Recommendation: Consistent findings from 2 cross-sectional studies and 1 survey study suggest level IIB evidence to support that ACL injury is associated with negative CV health.

Factors correlating with recovery of quadriceps strength after double-bundle anterior cruciate ligament reconstruction with hamstring tendon autografts.

Recovery of quadriceps strength after anterior cruciate ligament (ACL) reconstruction is one of the criteria used to promote rehabilitation and return to play. The purpose of this study was to investigate the factors associated with recovery of quadriceps strength after ACL reconstruction with hamstring tendon autografts. Isokinetic quadriceps strength at 60°/s was measured preoperatively and 6months after surgery in 101 patients (54 males and 47 females) who underwent double-bundle ACL reconstruction with hamstring tendon autografts. The quadriceps strength index (%) was calculated by normalizing the peak torque of the operated leg with that of the contralateral leg. Details on age, sex, body mass index, time from injury to surgery, pre-injury Tegner activity scale score, previous meniscus repair, and preoperative quadriceps strength index were recorded. The factors associated with the postoperative quadriceps strength index were investigated in univariate and multivariate regression analyses. Multivariate regression analysis showed that preoperative quadriceps strength index (p = 0.001) was independently associated with the quadriceps strength index at 6months after surgery. There was a marginally significant inverse association between age and postoperative quadriceps strength, but no statistically significant association was found for any of the other factors investigated. Postoperative quadriceps strength index at 6months after double-bundle ACL reconstruction with hamstring tendon autografts was affected by preoperative quadriceps strength index. Adequate preoperative quadriceps strength may need to be considered in order to facilitate better recovery of quadriceps strength after ACL reconstruction and to support an earlier return to sports activities.

Knee Loading After ACL-R Is Related to Quadriceps Strength and Knee Extension Differences Across the Continuum of Care.

Background:Quadriceps strength and knee extension are believed to be important in the ability to effectively load the knee after anterior cruciate ligament (ACL) reconstruction (ACL-R).Purpose:To compare quadriceps strength (QUADS), side-to-side knee extension difference (ExtDiff), and knee energy absorption contribution (EAC) in patients preoperatively, 12 weeks postoperatively, and at return to sport (RTS). A secondary aim was to determine how the factors of QUADS and ExtDiff contributed to the ability to load the knee (knee EAC) at each of the 3 time points.Study Design:Case series; Level of evidence, 4.Methods:Overall, 41 individuals (mean ± SD age, 15.95 ± 1.63 years) were enrolled in this study. QUADS, ExtDiff, and knee EAC during a double-limb squat were collected preoperatively, 12 weeks postoperatively, and at RTS. Isokinetic QUADS was collected at 60 deg/s, normalized to body mass, and averaged across 5 trials. Knee extension was measured with a goniometer, and ExtDiff was calculated for analyses. Knee EAC was measured during double-limb squat descent and was calculated as a percentage of total energy absorption for the limb. Observations were obtained from both the surgical and nonsurgical limbs at the 3 time points. A mixed regression model with random intercept to compare change over the 3 time points was used, and a model selection was conducted with Akaike information criteria. Significance was set at P < .05.Results:Surgical limb QUADS was significantly lower preoperatively (mean ± SD, 1.37 ± 0.49 N·m/kg; P = .0023) and at 12 weeks (1.11 ± 0.38 N·m/kg; P < .0001) than at RTS (1.58 ± 0.47 N·m/kg). Nonsurgical limb QUADS was also significantly lower preoperatively (2.01 ± 0.54 N·m/kg; P < .0256) and at 12 weeks (2.03 ± 0.48 N·m/kg; P < .0233) than at RTS (2.18 ± 0.54 N·m/kg). Knee EAC for the surgical limb was significantly lower at 12 weeks than at RTS (40.98% ± 13.73% vs 47.50% ± 12.04%; P < .0032), and ExtDiff was significantly greater preoperatively than at RTS (–2.68° ± 3.19° vs –0.63° ± 1.43°; P < .0001). Preoperatively, QUADS for both the surgical (P < .0003) and nonsurgical (P = .0023) limbs was a significant predictor of surgical limb knee EAC, explaining 33.99% of the variance. At 12 weeks, surgical limb QUADS was a significant predictor (P < .0051) of surgical limb knee EAC, explaining 18.83% of the variance. At RTS, ExtDiff was a significant predictor (P = .0201) of surgical limb knee EAC, explaining 12.92% of the variance.Conclusion:The ability to load the knee after ACL injury changes across the continuum of care and is related to QUADS and ExtDiff. These results provide clinicians with insight into potential contributing factors that may limit knee loading during the rehabilitation process.

Flexion Instability After Total Knee Arthroplasty.

Flexion instability after total knee arthroplasty (TKA) is caused by an increased flexion gap compared with extension gap. Patients present with recurrent effusions, subjective instability (especially going downstairs), quadriceps weakness, and diffuse periretinacular pain. Manual testing for laxity in flexion is commonly done to confirm a diagnosis, although testing positions and laxity grades are inconsistent. Nonsurgical treatment includes quadriceps strengthening and bracing treatment. The mainstays to surgical management of femoral instability involve increasing the posterior condylar offset, decreasing the tibial slope, raising the joint line in combination with a thicker polyethylene insert, and ensuring appropriate rotation of implants. Patient outcomes after revision TKA for flexion instability show the least amount of improvement when compared with revisions for other TKA failure etiologies. Future work is needed to unify reproducible diagnostic criteria. Advancements in biomechanical analysis with motion detection, isokinetic quadriceps strength testing, and computational modeling are needed to advance the collective understanding of this underappreciated failure mechanism.

Blood Flow Restriction Training Does Not Improve Quadriceps Strength After Anterior Cruciate Ligament Reconstruction

Objectives: Blood flow restriction training (BFRT) involves obstruction of venous outflow of working muscles during exercise and may lead to more substantial recovery of quadriceps strength after anterior cruciate ligament (ACL) reconstruction. The purpose of this study is to examine the effects of BFRT in ACL reconstruction patients before and after exposure to BFRT. Methods: This study was a randomized controlled trial in which 36 patients who had torn their ACL and were scheduled to undergo ACL reconstructive surgery (ACLR) with an autograft were randomized to receive exercise with BFRT (N=18) or exercise without BFRT (N=18). Participants in both groups performed the same exercise, but either did or did not have blood flow restricted. The exercise component of the intervention consisted of all subjects performing a single-leg isokinetic leg press, at an intensity of 70% of the subjects’ one-repetition maximum, for four sets of ten repetitions two times per week for 8 weeks beginning at 8 weeks post-operatively. Patients randomized to the BFRT group performed the leg-press exercise with a blood flow restriction cuff applied to the thigh and set to a limb occlusion pressure of 80 percent. All participants were concurrently undergoing standard ACL rehabilitation at the same physical therapy clinic. Bilateral isometric (recorded at a knee angle of 90°) and isokinetic (60°/second) quadriceps strength were recorded using a Biodex dynamometer (System 4, Shirley, NY) prior to ACLR and after the conclusion of the 8-week intervention. Peak isometric and isokinetic quadriceps strength were utilized to generate isometric and isokinetic quadriceps symmetry indices ((ACLR limb strength/Healthy limb strength) x100). Change from baseline symmetry scores were then generated using the following equation: (post-intervention symmetry - pre-intervention symmetry)/pre-intervention symmetry in order to account for possible differences in strength between groups prior to intervention delivery. Change from baseline isometric and isokinetic quadriceps symmetry scores were then compared between groups (exercise with BFRT, exercise without BFRT) using one-way analysis of variance tests with an a priori α set to P≤ 0.05. Effect sizes (Cohen’s d) and 95% confidence intervals were also computed. Results: No significant differences were found for change from baseline isokinetic quadriceps symmetry index (P=0.39, BFRT mean=-0.05, Control mean=-0.19) or change from baseline isometric quadriceps symmetry index (P=0.62, BFRT mean=-0.04, control mean=-0.10). The effect sizes for isokinetic quadriceps symmetry index (d=0.28, 95% CI= -0.37, 0.93) and isometric quadriceps symmetry (d=0.16, 95% CI= -0.49, 0.80) were small with confidence intervals that crossed zero. Conclusion: An 8-week blood flow resistance training + exercise intervention did not increase quadriceps muscle strength in patients who had undergone ACL reconstruction. Based on our findings, application of blood flow restriction training in ACL reconstruction patients to improve quadriceps strength may not be warranted. Future studies may benefit from a longer follow-up and larger sample size.

Age, gender, quadriceps strength and hop test performance are the most important factors affecting the achievement of a patient-acceptable symptom state after ACL reconstruction

PurposeTo assess the percentage of patients achieving an acceptable symptom state 2 years after primary anterior cruciate ligament reconstruction (ACLR) and to identify factors affecting its achievement, in a large cohort.MethodsPatients who underwent primary ACLR at Capio Artro Clinic, Stockholm, Sweden, from 2005 to 2015, were identified in our clinic registry. Patients who had completed the Knee injury and Osteoarthritis Outcome Score (KOOS) at the 2-year follow-up were included. The primary outcome was the achievement of a patient-acceptable symptom state (PASS) for each KOOS subscale. A multivariate logistic regression analysis was used to determine whether patient age, gender, time from injury to surgery, pre-injury Tegner activity level, graft type, cartilage injury, the presence of medial meniscus (MM) or lateral meniscus (LM) resection or repair and the recovery of 6-month symmetrical (limb symmetry index [LSI] of ≥ 90%) isokinetic quadriceps or hamstring strength and single-leg-hop test performance were factors associated with the achievement of a PASS for each KOOS subscale.ResultsA total of 2335 primary ACLRs were included. More than 60% of the patients reported a PASS on four of the five KOOS subscales. Age ≥ 30 years and an LSI of ≥ 90% for 6-month isokinetic quadriceps strength increased the odds of achieving a PASS across all KOOS subscales. Female gender reduced the odds of achieving a PASS on the Pain (OR 0.76; 95% CI 0.62–0.94; P = 0.01), activities of daily living (ADL) (OR 0.79; 95% CI 0.64–0.97; P = 0.02) and sport and recreation (OR 0.72; 95% CI 0.58–0.89; P = 0.003) subscales. The presence of an MM repair reduced the odds of achieving a PASS on the Pain (OR 0.59; 95% CI 0.36–0.96; P = 0.03) subscale. Hamstring tendon (HT) autograft rather than bone-patellar tendon-bone (BPTB) autograft showed increased odds (OR 2.02; 95% CI 1.31–3.10; P = 0.001), whereas a cartilage injury showed reduced odds (OR 0.73; 95% CI 0.55–0.97; P = 0.03) of achieving a PASS on the sport and recreation subscale. An LSI of ≥ 90% for 6-month single-leg-hop test performance increased the odds of achieving a PASS on the ADL (OR 1.37; 95% CI 1.09–1.71; P = 0.005), Sport and Recreation (OR 1.40; 95% CI 1.11–1.77; P = 0.004), and quality of life (OR 1.28; 95% CI 1.00–1.63; P = 0.04) subscales.ConclusionMore than 60% of the patients reported an acceptable symptom state on four of the five KOOS subscales 2 years after primary ACLR. Age ≥ 30 years and female gender were the non-modifiable factors that consistently increased and reduced, respectively, the odds of achieving a PASS. A symmetrical 6-month isokinetic quadriceps strength and single-leg-hop test performance were the modifiable factors that consistently increased the opportunity of achieving a PASS 2 years after primary ACLR.Level of evidenceIII.