Surgical Limbs Research Articles

Reliability of a qualitative movement assessment tool during a single-leg triple hop landing

ObjectiveAssess inter- and intra-rater reliability of the Qualitative Analysis of Single Leg Squat (QASLS) during a single-leg triple hop landing in subjects following anterior cruciate ligament reconstruction (ACLR). Explore if differences in reliability existed between novice and experienced clinicians. Determine if QASLS scores differed between the surgical and nonsurgical limbs. DesignRepeated Measures. Participants20 subjects ≥6 months post-ACLR. MethodsSubjects were recorded performing a single-leg triple hop bilaterally. Videos were independently rated by five raters (2 physical therapists and 3 physical therapy students). Intraclass correlation coefficient (ICC) was calculated to measure reliability of the QASLS on the surgical limb. Wilcoxon signed-rank test was utilized to assess if differences in QASLS scores existed between limbs. ResultsThe cumulative inter-rater reliability was moderate (ICC (2,1): 0.703) and the cumulative intra-rater reliability was good (ICC (3,1): 0.857). Little difference was found between experienced and novice raters for inter- and intra-rater reliability. There was no statistically significant difference in QASLS scores between limbs (P = 0.64). ConclusionThe QASLS tool offers moderate inter- and good intra-rater reliability for evaluating movement quality during a single-leg triple hop landing, irrespective of rater experience. Additionally, there was no observed difference in QASLS scores between surgical and nonsurgical limbs.

Knee extensor torque-velocity relationships following anterior cruciate ligament reconstruction

BackgroundThe inherent nature of the torque-velocity relationship is the inverse nature between the velocity of muscle contraction and torque production and is an indication of muscle function. The purpose of this study was to characterize the torque-velocity relationship in the quadriceps following anterior cruciate ligament reconstruction compared to healthy limbs. Methods681 participants were included, 493 of which were patients at least four months following anterior cruciate ligament reconstruction (23.2 ± 10.08 yr, 6.6 ± 5.37 months post-surgery) and 188 were healthy participants (21.6 ± 3.77 yr). A subset of 175 post-surgical participants completed a repeated visit (8.1 ± 1.71 months post-surgery). Participants completed isokinetic knee extension at 90°/s and 180°/s. A one-way ANOVA was used to compare torque velocity relationships by limb type (surgical, contralateral, healthy). Paired samples t-tests were conducted to analyze the torque-velocity relationship across limbs and across time. FindingsThere was a large effect for limb type on torque-velocity (F(2, 1173) = 146.08, p < 0.001, η2 = 0.20). Surgical limbs demonstrated significantly lower torque-velocity relationships compared to the contralateral limbs (ACLR: 0.26 Nm/kg, contralateral:0.55 Nm/kg, p < 0.001, d = 1.18). Healthy limbs had similar torque-velocity relationships bilaterally (dominant limb: 0.48 Nm/kg, non-dominant limb: 0.49 Nm/kg, p = 0.45). The torque velocity relationship for the involved limb significantly increased in magnitude over time (+0.11 Nm/kg, p < 0.001, d = −0.61) while the contralateral limb torque-velocity relationship remained stable over time (0.0 Nm/kg difference, p = 0.60). InterpretationFollowing surgery, the knee extensors appear to have altered torque-velocity relationships compared to contralateral and healthy limbs. This may indicate a specific target for assessment and rehabilitation following surgery.

Coordination of the Lower Limbs of Soccer Players after Anterior Cruciate Ligament Reconstruction with Allograft and Autograft during Landing.

Quantitative biomechanical tests, along with physical assessment, may be useful to understand kinematics associated with graft types in anterior cruciate ligament surgery, particularly in individuals aiming for a safe return to sport. Sixty male soccer players in three groups participated in this study. Three equal groups of healthy, auto transplanted and allotransplanted participants, matched for age, gender, activity level and functional status, landed with one foot on a force plate. Their kinematic information was recorded by the motion analyzer and used to describe coordination the variability by measuring coupling angles using vector coding. The coordination variability of the allograft group in the surgical limb was significantly greater than that of the healthy group at least 9 months after the reconstructive surgery of the ACL and at the stage of return to sports, (F (6, 35) = 2.79, p = 0.025; Wilk's Λ = 0.676, partial η2 = 0.32). The coordination pattern in the surgical and healthy limbs of the surgical groups also differed from that of the healthy people, which was more pronounced in the allograft group, (F (6, 35) = 2.61, p = 0.034; Wilk's Λ = 0.690, partial η2 = 0.31). These results show that the allograft group has a different coordination variability at return to sport than the healthy group, so they may need more time for excessive training and competition.

Functional performance in runners after knee surgery: Differences between limbs and relationships with pain and confidence

Introduction: Single leg functional performance tests, such as hop for distance and side hop tests, are commonly used assessments in rehabilitation following knee surgery as they are linked to self-reported function and quality of life. Little is known about how such tests differ between surgical and non-surgical limbs in those who return to running following knee surgery, and how much pain and/or confidence during the test impacts performance. Therefore, we aimed to explore differences in single leg functional performance between surgical and non-surgical limbs in runners with a history of knee surgery, and to explore how pain and confidence relates to performance.

Additive Manufacturing: Vat Polymerization for Medical Applications

Abstract Vat polymerization uses ultraviolet light to harden liquid photosensitive resins into medical products such as surgical models and artificial limbs.

Gait-related Factors That Explain Power Production In Patients Before And After Total Ankle Arthroplasty

Total ankle arthroplasty (TAA) reduces pain and improves joint function, including power production at the ankle. Patients can ambulate at higher velocities and generate greater joint power after TAA. To date, little is known about which factors – angular velocity (AV), ground reaction force (GRF), or range of motion (ROM) – most influence power production before and after TAA. Identifying the factors that affect power production and their relative contribution can provide rehabilitation targets. PURPOSE: To examine the role of ankle kinematics and kinetics in generating power in the last third of the stance phase and to evaluate which factors play the most important role in generating increased power after surgery. It is hypothesized that reduction in pain will primarily increase GRF and AV to a greater degree than ankle ROM. METHODS: Two hundred and eighteen patients (101 male and 117 female; age = 63.1 + 9.4) with requiring TAA were studied using a motion analysis system and force plates before and after TAA. Peak ankle power and associated vertical GRF (vGRF), center of pressure (COP) position, ankle angle, moment and AV were compared before and after surgery using Wilcoxon signed rank tests. Predictive models for pre and post surgical power generation were created using AIC multiple stepwise regression. RESULTS: Following TAA, ankle plantarflexion power increased on both the surgical and nonsurgical limbs (0.83 to 1.1, p < 0.001; 0.97 to 1.4, p < 0.001 respectively). To increase power, patients increased surgical and non-surgical side vGRF (0.51 to 0.58, p < 0.001; 0.51 to 0.57, p = 0.002 respectively) and AR (1.1 to 1.7, p < 0.001; 1.1 to 1.8, p < 0.001 respectively). Ankle ROM did not change significantly on either limb following surgery. Ankle AV and vGRF are the best predictors of peak plantar flexion power across all models, with AV being the strongest single predictor. CONCLUSIONS: TAA improves power production at the ankle by allowing patients to generate a greater force at a higher rate. Increased power production relates to faster and more efficient gait, relieving other joints of the need to generate compensatory power. Pre and post-TAA treatment strategies should focus on helping patients increase vGRF and plantarflexion angular velocity during terminal stance to improve physical functional before and after TAA.

Effects of Limb Dominance on Patellofemoral Joint Loading During Gait at 12 Weeks After Anterior Cruciate Ligament Reconstruction.

Background:Patellofemoral joint complications have commonly been reported in long-term outcome studies for anterior cruciate ligament reconstruction (ACLR); however, the biomechanics in the early phases of rehabilitation that could be associated with the development of these abnormalities is unclear. Limb dominance may affect the biomechanics of the knee joint in patients after ACLR.Purpose:To compare knee joint loading between surgical and nonsurgical limbs at 12 weeks postoperatively in patients who underwent ACLR on either their dominant limb (ACL-D) or nondominant limb (ACL-ND).Study Design:Controlled laboratory study.Methods:Included were 54 patients (32 ACL-D and 22 ACL-ND). Peak and integrated patellofemoral joint stress (PFJS), peak patellofemoral joint reaction force (PFJRF), and peak knee extension moment (KEM) were assessed during the stance phase of gait while participants walked on a 10-m runway at a self-selected speed.Results:The surgical limb of the ACL-D group had significantly decreased peak PFJS (P < .001), integrated PFJS (P < .001), peak PFJRF (P < .001), and peak KEM (P < .001) compared to the nonsurgical limb. The surgical limb of the ACL-ND group demonstrated significantly increased peak PFJS (P = .001), integrated PFJS (P = .023), peak PFJRF (P < .001), and peak KEM (P = .001) compared to the nonsurgical limb. For the surgical limb, the ACL-ND group demonstrated significantly greater peak PFJS (P < .001), peak PFJRF (P < .001) , (PFJRF [P<.001]) and peak KEM (P < .001) than the ACL-D group. For the nonsurgical limb, the ACL-D group demonstrated greater peak PFJS (P < .001), integrated PFJS (P = .023), peak PFJRF (P = .003), and peak KEM (P < .001) than the ACL-ND group.Conclusion:Significantly larger knee joint loading on the surgical limb of the ACL-ND group and smaller knee joint loading on the surgical limb of the ACL-D group were observed compared to the contralateral nonsurgical limb, which suggests that limb dominance has a key role in loading at the knee joint during gait.Clinical Relevance:Altered knee joint loading during gait at 12 weeks after ACLR may lead to the development of patellofemoral joint abnormalities.

Effects of Male and Female Sex on the Development of Posttraumatic Osteoarthritis in the Porcine Knee After Anterior Cruciate Ligament Surgery

Background: Posttraumatic osteoarthritis (PTOA) is a common sequela of anterior cruciate ligament (ACL) injury, even when surgical treatment is selected. The effect of patient sex on cartilage health after ACL injury and surgical treatment has been less studied. Purpose/Hypothesis: The study objective was to compare the macroscopic cartilage damage that develops after ACL surgery in male and female Yucatan minipigs. It was hypothesized that after ACL surgery, the macroscopic cartilage damage of the tibiofemoral joints from female animals would be greater than that from male animals. Additionally, it was hypothesized that the effect of sex on the macroscopic cartilage damage would depend on surgical treatment. Study Design: Controlled laboratory study Methods: Twelve-month follow-up data were obtained for 55 adolescent Yucatan minipigs (22 female/33 male) that were randomized to 1 of 3 experimental groups: no treatment (ACL transection [ACLT]), ACL reconstruction, and bridge-enhanced ACL restoration. The Osteoarthritis Research Society International guidelines were used to determine a standardized macroscopic cartilage damage score on 5 surfaces of the knee joint. Results: Females had significantly worse mean total macroscopic cartilage damage scores on the surgical side (adjusted P value [P adj] = .04) and significantly better scores on the contralateral side (P adj = .01) when compared with males. The trochlear damage scores were also significantly worse in females for surgical limbs (P adj = .009) and significantly better for the contralateral limbs (P adj < .001) when compared with males. Although there were no significant differences in total macroscopic cartilage damage scores between sexes within treatment groups on the surgical limbs (ACLT, P adj = 0.45; ACL reconstruction, P adj = .56; bridge-enhanced ACL restoration, P adj = .23), the mean trochlear scores on the surgical limb of females were significantly worse than those of the males in the ACLT group (P adj = .003). Conclusion: Mean total macroscopic cartilage damage scores of Yucatan minipigs were significantly worse in females than males, regardless of treatment. These differences were predominantly found in the trochlear scores across all treatment groups. Clinical Relevance: These data suggest that patient sex could be more influential in the progression of PTOA than surgical treatment after ACL injury. Identifying factors responsible for this discrepancy may prove valuable to identify targets to slow PTOA progression in male and female ACL-injured populations.

The Effects of Blood Flow Restriction Training on Strength and Function During Early Rehabilitation After Anterior Cruciate Ligament Reconstruction in Adolescents

Background:Blood flow restriction training (BFRT) has gained popularity due to reported benefits in reducing muscle atrophy and mitigating strength deficits following anterior cruciate ligament reconstruction (ACLR). While there are a number studies that have reported on the use of BFRT in the adult population, there is limited information about the use of BFRT in the adolescent population and its effect on muscle strength and function.Hypothesis/purpose:The purpose of this study was to determine the effect of adding BFRT to traditional rehabilitation in the adolescent population after ACLR. This study’s primary aim was to investigate the impact BFRT has on isometric strength testing and patient reported function at 3 months post-operatively.Methods:A prospective intervention group was compared to an age matched retrospective control group as part of an ongoing clinical trial. This included patients between 12 and 18 years of age, who underwent primary ACLR at Connecticut Children’s from January 2020 to present. In addition to a standardized rehabilitation protocol these patients utilized a personalized tourniquet system for BFRT with limb occlusion pressure of 80%. A standardized BFRT protocol was followed over initial 12 weeks, completing 3 BFRT exercises per session. Load progression was based on the patient’s perceived level of exertion. A three month strength assessment was completed by patients in both groups. The test included isometric knee extension and flexion strength at 60° of knee flexion. Peak torque was normalized to body weight and used to calculate limb symmetry index (LSI). IKDC scores were recorded. Two-sample t tests were used to determine differences between the BFRT and control groups.Results:The BFRT group consisted of 11 patients (6 females; 14.9 ± 1.8 years old). The control group consisted of 47 patients (24 females; 15.2 ± 0.6 years old). Age, height, and weight were not significantly different between groups (Table 1). Significant differences were seen between the BFRT and control groups for peak knee extensor torque when normalized to body weight in both the surgical (1.8 ± 0.4 vs 1.4 ± 0.6 Nm/kg, p=0.02) and nonsurgical limbs (2.7 ± 0.6 vs 2.1 ± 0.5 Nm/kg, p=0.03) (Table 2). No significant differences were seen between groups for knee extensor or flexor LSI or IKDC scores (Table 2).Conclusions:In adolescents, BFRT may impact bilateral knee extensor force production during early post-operative ACLR rehabilitation. Continued investigation is needed to further evaluate the impact of BFRT in this population.Table 1.Patient DemographicsTable 2.Isometric Strength Tests and IKDC

Knee Strength Outcomes in Adolescents by Age and Sex During Late-Stage Rehabilitation After Anterior Cruciate Ligament Reconstruction

Background:The incidence of anterior cruciate ligament (ACL) injuries have been consistently increasing in adolescents, with those who return to competitive sport having up to a 32% risk of a secondary ACL injury. There is limited evidence regarding knee strength outcomes in young adolescents following ACL reconstruction during late-stage rehabilitation when compared to older patient groups.Purpose:The purpose of this study was to 1) establish normative knee strength values according to age group in adolescent female and male patients during late-stage rehabilitation following ACLR and 2) determine whether strength differences exist between age groups.Methods:A retrospective review of adolescent patients who underwent primary ACL reconstruction was performed. Patients completed a standardized isokinetic (60°/sec) knee extension and flexion strength assessment during late-stage rehabilitation. Peak torque was normalized to the patient’s body mass (Nm/kg) and used to calculate Limb Symmetry Index (LSI). Analyses were conducted separately for female and male cohorts and grouped by early (11-14 years) and middle (15-17 years) adolescence. An independent samples t-test examined strength differences between age groups.Results:130 females (age=15.4 ± 1.4 years; days since surgery=239.0 ± 84.4) and 112 males (age=15.4 ± 1.5 years; days since surgery= 232.6 ± 91.2) were included. Normalized knee extension peak torque on the involved limb was reported for female (1.5 Nm/kg) and male (1.8 Nm/kg) cohorts. Differences between age groups in knee extension peak torque were found on the surgical and nonsurgical limbs in female (p = 0.02 – 0.05) and male (p<0.001 – 0.002) cohorts. No differences were found between age groups for either cohort when normalized to body mass (p = 0.30 – 0.89). Post hoc power analyses revealed 67% statistical power in the female cohort and 97% in the male cohort with an alpha level set to 0.05 based on the observed effect size for the differences in isokinetic knee extension/flexion peak torque between age groups.Conclusion:Early adolescents produced less knee extension and flexion peak torque compared to middle adolescents after ACLR, but no differences were found between age groups when normalized to body mass for female or male cohorts. Normalized knee extension strength in young adolescents may differ from older patients and should be considered in the rehabilitation process.TABLE 1:Patient Demographics - FemalesTABLE 2:Patient Demographics - MalesTABLE 3:Strength Outcomes by Age Group during Late-Stage Rehabilitation (Females)TABLE 4:Strength Outcomes by Age Group during Late-Stage Rehabilitation (Males)

Perioperative assessment of muscle inflammation susceptibility in patients with end-stage osteoarthritis.

Many individuals with end-stage osteoarthritis (OA) undergo elective total hip/knee arthroplasty (THA/TKA) to relieve pain, improve mobility and quality of life. However, ∼30% suffer long-term mobility impairment following surgery. This may be in part due to muscle inflammation susceptibility (MuIS+), an overt proinflammatory pathology localized to skeletal muscle surrounding the diseased joint, present in some patients with TKA/THA. We interrogated the hypothesis that MuIS+ status results in a perturbed perioperative gene expression profile and decreases skeletal muscle integrity in patients with end-stage OA. Samples were leveraged from the two-site, randomized, controlled trial R01HD084124, NCT02628795. Participants were dichotomized based on surgical (SX) muscle gene expression of TNFRSF1A (TNF-αR). MuIS+/- samples were probed for gene expression and fibrosis. Paired and independent two-tailed t tests were used to determine differences between contralateral (CTRL) and surgical (SX) limbs and between-subject comparisons, respectively. Significance was declared at P < 0.05. Seventy participants (26M/44F; mean age 62.41 ± 8.86 yr; mean body mass index 31.10 ± 4.91 kg/m2) undergoing THA/TKA were clustered as MuIS+ (n = 24) or MuIS- (n = 46). Lower skeletal muscle integrity (greater fibrosis) exists on the SX versus CTRL limb (P < 0.001). Furthermore, MuIS+ versus MuIS- muscle exhibited higher proinflammatory (IL-6R and TNF-α) and catabolic (TRIM63) gene expression (P < 0.001, P = 0.004, and 0.024 respectively), with a trend for greater fibrosis (P = 0.087). Patients with MuIS+ exhibit more inflammation and catabolic gene expression in skeletal muscle of the SX limb, accompanied by decreased skeletal muscle integrity (Trend). This highlights the impact of MuIS+ status emphasizing the potential value of perioperative MuIS assessment to inform optimal postsurgical care.NEW & NOTEWORTHY This study assessed the skeletal muscle molecular characteristics associated with end-stage osteoarthritis and refined an important phenotype, in some patients, termed muscle inflammation susceptibility (MuIS+) that may be an important consideration following surgery. Furthermore, we provide evidence of differential inflammatory and catabolic gene expression between the contralateral and surgical limbs along with differences between the skeletal muscle surrounding the diseased hip versus knee joints.

Knee muscle strength in runners who have had knee surgery: differences between limbs and associations with functional performance

Introduction: Knee muscle weakness has been associated with an increased risk of various overuse injuries in runners and incident knee osteoarthritis; however, little is known about knee strength in runners, particularly those who are at high risk of osteoarthritis who have previously had knee surgery. The aim of this study was to explore differences in knee extensor and flexor strength between surgical and non-surgical limbs in runners with a history of knee surgery, and to explore if knee strength is associated with functional performance. Methods: A convenience sample of 38 runners (run ≥10km/week, ≥3 sessions/week) who had unilateral knee surgery (45% anterior cruciate ligament reconstruction) were recruited (33.2±6.8 years, 11 women). Three maximal voluntary isometric contractions of the knee extensors and flexors were performed at 60° knee flexion (Biodex dynamometer). The highest torque value (Nm) for the knee extensors and flexors for each leg was used for analysis. Functional performance was assessed via three trials of the hop for distance test, with the furthest distance hopped for each leg recorded. Paired t-tests were used to explore differences in knee strength between limbs (whole group and stratified by sex) and partial correlations were used to explore associations between knee strength and hop for distance, controlling for mass, age, and sex. Results: There was no significant difference in knee extensor strength between the surgical and non-surgical limbs (surgical=205.9±53.4Nm, non-surgical=215.5±57.9Nm; p=0.087, Cohen’s d=0.285). A significant difference was observed between limbs for knee flexor strength (surgical=103.6±24.1Nm, non-surgical=112.3±28.6Nm; p=0.001, Cohen’s d=0.576). When examining men only, the same results were found, but there were no significant differences between limbs for women. Small to moderate non-significant associations were observed between knee strength and hop for distance on both the surgical (knee extensor r=0.321, p=0.060; knee flexor r=0.333, p=0.051) and non-surgical limbs (knee extensor r=0.286, p=0.095; knee flexor r=0.093, p=0.596). Discussion: Runners who have had unilateral knee surgery demonstrate knee flexor weakness in the surgical limb, but not knee extensors, although differences may be sex specific. Small to moderate non-significant associations between knee strength and hop for distance indicate that factors other than knee strength may influence functional performance in runners who have had knee surgery. Conflict of interest statement: My co-authors and I acknowledge that we have no conflict of interest of relevance to the submission of this abstract.

Suppressed quadriceps fascicle behavior is present in the surgical limbs of those with a history of ACL reconstruction

The balance of published data have largely focused on adaptations in muscle and fiber size after anterior cruciate ligament reconstruction (ACLR), failing to account for the dynamic changes in the behavior of the muscles’ contractile elements that strongly contribute to force production. To better understand the sources of quadriceps dysfunction, the purpose of our research was to determine if alterations in fascicle behavior are present after ACLR. Unilateral ACLR individuals (9 m/9f; 21 ± 3 yrs; 1.74 ± 0.12 m;71.58 ± 13.31 kg; months from surgery:38 ± 36) and healthy controls (3 m/6f; 23 ± 2 yrs; 1.67 ± 0.10 m; 63.51 ± 10.11 kg) participated. In-vivo vastus lateralis fascicle behavior was recorded using ultrasonography during three maximal isokinetic knee extensions (60°·s−1). Fascicle length, angle, and shortening velocity were calculated and analyzed from rest to peak torque. Peak knee extension torque was averaged between isokinetic trials (Nm·kg−1). Group by limb interactions were assessed using separate two-way analyses of variance and were further evaluated by comparing 95% confidence intervals where appropriate. Significant interactions were present for fascicle angle at peak torque (P = 0.01), fascicle length excursion (P = 0.05), fascicle angle excursion (P < 0.01), fascicle shortening velocity (P = 0.05) and strength (P = 0.03). Upon post-hoc evaluation, the surgical limb displayed altered in-vivo fascicle behavior compared to all limbs (P < 0.05) and reduced strength compared to the contralateral and right control limbs (P < 0.05). No other significant interactions were present (P > 0.05). Our data show that those with a history of ACLR have fascicles that are slower, lengthen less and operate with lower angles relative to the axis of force production. Altered fascicle behavior after ACLR may be an important underlying factor to explaining the protracted quadriceps dysfunction.

Instructed Squat Improves Limb But Not Knee Extensor Moment Symmetry In Individuals Following ACLr.

Recent work found that individuals in early recovery post-ACL reconstruction (ACLr) spontaneously underload the surgical (Sx) limb and knee extensors in double limb tasks. With instructions to focus on equalizing weight under the feet, they are able to improve limb loading symmetry during a squat exercise. However, it is not known if these instructions can also improve knee extensor moment (kEXTmmt) symmetry. PURPOSE: To determine if instructions to equalize between limb loading improve kEXTmmt. METHODS: 14 subjects (6 male; 27 (11) yrs; 116.4 (16.6) days post-ACLr) performed bilateral squats to self-selected depths under natural (N) and instructed (I) conditions. In I condition, subjects were asked to concentrate on equalizing weight under both feet; no instructions were given in N condition. 3-D kinematics (250 Hz), ground reaction forces (1500 Hz), anthropometrics were used to calculate kEXTmmt (inverse dynamics). Vertical ground reaction force (vGRF) and kEXTmmt were averaged across the squat cycle for surgical (Sx) and non-surgical (NSx) limbs; 3 trials. The effect of instruction on vGRF and kEXTmmt was assessed using a (condition x limb) repeated measures ANOVA; post hoc paired t-test (p < 0.05). RESULTS: Condition x limb interaction was found (vGRF p = 0.007, kEXTmmt p = 0.002). Sx limb vGRF (Sx 335.29 (52.78) vs NSx 376.95 (67.75) N; p = 0.015) and kEXTmmt (Sx -0.33 (0.15) vs NSx -0.63 (0.17)Nm/kg; p < 0.001) were smaller in N condition. Sx limb kEXTmmt (Sx -0.35 (0.16) vs NSx -0.53 (0.15) Nm/kg; p = 0.002) was smaller in I condition; no difference was observed between limbs in vGRF. CONCLUSIONS: Individuals following ACLr adopt strategies that shift mechanical demands away from the knee of the surgical limb in early recovery. These strategies persist long term. Instruction to distribute weight symmetrically during squatting restored limb loading but did not restore kEXTmmt symmetry. These data suggest that these commonly employed corrective instructions are not adequate to retrain sagittal plane knee loading in early recovery post-ACLr.

Running Biomechanics Before Injury and 1 Year After Anterior Cruciate Ligament Reconstruction in Division I Collegiate Athletes

Background: Preinjury running biomechanics are an ideal comparator for quantifying recovery after anterior cruciate ligament (ACL) reconstruction (ACLR), allowing for assessments within the surgical and nonsurgical limbs. However, availability of preinjury running biomechanics is rare and has been reported in case studies only. Purpose/Hypothesis: The purpose of this study was to determine if running biomechanics return to preinjury levels within the first year after ACLR among collegiate athletes. We hypothesized that (1) surgical knee biomechanics would be significantly reduced shortly after ACLR and would not return to preinjury levels by 12 months and (2) nonsurgical limb mechanics would change significantly from preinjury. Study Design: Cohort study; Level of evidence, 2. Methods: Thirteen Division I collegiate athletes were identified between 2015 and 2020 (6 female; mean ± SD age, 20.7 ± 1.3 years old) who had whole body kinematics and ground-reaction forces recorded during treadmill running (3.7 ± 0.6 m/s) before sustaining an ACL injury. Running analyses were repeated at 4, 6, 8, and 12 months (4M, 6M, 8M, 12M) after ACLR. Linear mixed effects models were used to assess differences in running biomechanics between post-ACLR time points and preinjury within each limb, reported as Tukey-adjusted P values. Results: When compared with preinjury, the surgical limb displayed significant deficits at all postoperative assessments (P values <.01; values reported as least squares mean difference [SE]): peak knee flexion angle (4M, 13.2° [1.4°]; 6M, 9.9° [1.4°]; 8M, 9.8° [1.4°]; 12M, 9.0° [1.5°]), peak knee extensor moment (N·m/kg; 4M, 1.32 [0.13]; 6M, 1.04 [0.13]; 8M, 1.04 [0.13]; 12M, 0.87 [0.15]; 38%-57% deficit), and rate of knee extensor moment (N·m/kg/s; 4M, 22.7 [2.4]; 6M, 17.9 [2.3]; 8M, 17.5 [2.4]; 12M, 16.1 [2.6]; 33%-46% deficit). No changes for these variables from preinjury (P values >.88) were identified in the nonsurgical limb. Conclusion: After ACLR, surgical limb knee running biomechanics were not restored to the preinjury state by 12M, while nonsurgical limb mechanics remained unchanged as compared with preinjury. Collegiate athletes after ACLR demonstrate substantial deficits in running mechanics as compared with preinjury that persist beyond the typical return-to-sport time frame. The nonsurgical knee appears to be a valid reference for recovery of the surgical knee mechanics during running, owing to the lack of change within the nonsurgical limb.

Clinically Important Reductions in Physical Function and Quality of Life in Adults with Tumor Prostheses in the Hip and Knee: A Cross-sectional Study.

Clinically Important Reductions in Physical Function and Quality of Life in Adults with Tumor Prostheses in the Hip and Knee: A Cross-sectional Study.

A Review on Structural Configurations of Magnetorheological Fluid Based Devices Reported in 2018–2020

Magnetorheological fluid (MRF) is a kind of smart materials with rheological behavior change by means of external magnetic field application, which has been widely adopted in many complex systems of different technical fields. In this work, the state-of-the-art MRF based devices are reviewed according to structural configurations reported from 2018 to 2020. Based on the rheological characteristic, the MRF has a variety of operational modes, such as flow mode, shear mode, squeeze mode and pinch mode, and has unique advantages in some special practical applications. With reference to these operational modes, improved engineering mechanical devices with MRF are summarized, including brakes, clutches, dampers, and mounts proposed over these 3 years. Furthermore, some new medical devices using the MRF are also investigated, such as surgical assistive devices and artificial limbs. In particular, some outstanding advances on the structural innovations and application superiority of these devices are introduced in detail. Finally, an overview of the significant issues that occur in the MRF based devices is reported, and the developing trends for the devices using the MRF are discussed.

Quadriceps strength changes across the continuum of care in adolescent male and female athletes with anterior cruciate ligament injury and reconstruction

ObjectivesTo examine the quadriceps strength (QUADS) on the surgical (SURG) and non-surgical (Non-SURG) limbs in adolescent male and female athletes at pre-operative (PRE), 12 weeks post-operative (12WK), and return to sport (RTS) time points following ACL injury and reconstruction. DesignProspective cohort study design. SettingClinical Research Laboratory. Participants66 adolescent athletes. Main outcome measuresIsokinetic QUADS of the SURG and Non-SURG limbs at the PRE, 12WK, and RTS time points were assessed and compared between each time point. ResultsBoth male and female participants had significantly lower 12 WK QUADS in the SURG limb than the PRE QUADS, but the RTS QUADS was significantly greater than the 12WK QUAD (p < 0.05). However, only female participants had greater RTS QUADS as compared to the PRE QUADS (p < 0.001). For the Non-SURG limb, only male participants had a significant improvement over time (PRE vs RTS; p < 0.001). ConclusionAdolescent males and females differ in their QUADS recovery across the continuum of care following ACLR. Clinicians should consider this pattern of recovery when treating adolescent males and females.

Effects Of Community-based Supervised Exercise In The Body Composition And Strength Of Breast Cancer Survivors

PURPOSE: To analyze the effects of a low-cost community-based supervised exercise program on body composition and muscle strength in breast cancer survivors. METHODS: Twenty-one female survivors of breast cancer concluded a single-arm clinical trial with a control and an experimental phase. Each participant was evaluated in 5 consecutive moments: 16 and 8 weeks before intervention (M1 and M2), immediately before intervention (M3), and 8 and 16 weeks after the exercise program started (M4 and M5). Participants benefited from conventional care during the control phase (M1 to M3) followed by a community-based exercise program (M3 to M5). This consisted of 3 sessions per week of 60-min combining aerobic and strength exercise at moderate to vigorous intensity in group classes of no more than 20 participants with low-cost material. Body mass index (BMI), handgrip strength and sit-to-stand (STS) test were assessed in all the evaluation moments. RESULTS: There were significant increases through time in handgrip strength in both surgical and non-surgical upper limbs (p<0.0001) and in lower limbs functional strength (p<0.0001) (table). BMI increased during control phase and decreased during the initial phase of exercise training program (p=0.050). Serious adverse events were not reported. CONCLUSIONS: A low-cost community-based supervised exercise program is safe and improves body composition and strength in breast cancer survivors after primary treatment.Legend: Results were tested with repeated measures analysis of variance and are presented as mean±SD; Post-Hoc analysis were corrected with Bonferroni. Effect size was calculated as Partial Eta Squared.*Higher than M1; ** Higher than M1-M3; ***Higher than M1-M4; † Higher than M1-M2; ‡ Higher than M3; p<0.05.

Magnetic resonance imaging and bioimpedance evaluation of lymphatic abnormalities in patients with breast cancer treatment-related lymphedema.

Breast cancer treatment-related lymphedema (BCRL) evaluation is frequently performed using portable measures of limb volume and bioimpedance asymmetry. Here quantitative magnetic resonance imaging (MRI) is applied to evaluate deep and superficial tissue impairment, in both surgical and contralateral quadrants, to test the hypothesis that BCRL impairment is frequently bilateral and extends beyond regions commonly evaluated with portable external devices. 3-T MRI was applied to investigate BCRL topographical impairment. Female BCRL (n = 33; age = 54.1 ± 11.2years; stage = 1.5 ± 0.8) and healthy (n = 33; age = 49.4 ± 11.0years) participants underwent quantitative upper limb MRI relaxometry (T2), bioimpedance asymmetry, arm volume asymmetry, and physical evaluation. Parametric tests were applied to evaluate study measurements (i) between BCRL and healthy participants, (ii) between surgical and contralateral limbs, and (iii) in relation to clinical indicators of disease severity. Two-sided p-value < 0.05 was required for significance. Bioimpedance asymmetry was significantly correlated with MRI-measured water relaxation (T2) in superficial tissue. Deep muscle (T2 = 37.6 ± 3.5ms) and superficial tissue (T2 = 49.8 ± 13.2ms) relaxation times were symmetric in healthy participants. In the surgical limbs of BCRL participants, deep muscle (T2 = 40.5 ± 4.9ms) and superficial tissue (T2 = 56.0 ± 14.8ms) relaxation times were elevated compared to healthy participants, consistent with an edematous micro-environment. This elevation was also observed in contralateral limbs of BCRL participants (deep muscle T2 = 40.3 ± 5.7ms; superficial T2 = 56.6 ± 13.8ms). Regional MRI measures substantiate a growing literature speculating that superficial and deep tissue, in surgical and contralateral quadrants, is affected in BCRL. The implications of these findings in the context of titrating treatment regimens and understanding malignancy recurrence are discussed.