Associations of inflammatory and metabolic biomarkers with incident erosive hand osteoarthritis in the osteoarthritis initiative cohort.

OBJECTIVE: Erosive hand osteoarthritis (eHOA) is a subtype of hand osteoarthritis (OA) that develops in finger joints with pre-existing OA and is differentiated by clinical characteristics (hand pain/disability, inflammation, and erosions) that suggest inflammatory or metabolic processes. METHOD: This was a longitudinal nested case-cohort design among Osteoarthritis Initiative participants who had hand radiographs at baseline and 48-months, and biospecimens collected at baseline. We classified incident radiographic eHOA in individuals with ≥1 joint with Kellgren-Lawrence ≥2 and a central erosion present at 48-months but not at baseline. We used a random representative sample (n = 1282) for comparison. We measured serum biomarkers of inflammation, insulin resistance and dysglycemia, and adipokines using immunoassays and enzymatic colorimetric procedures, blinded to case status. RESULTS: Eighty-six participants developed incident radiographic eHOA. In the multivariate analyses adjusted for age, gender, race, smoking, and body mass index, and after adjustment for multiple analyses, incident radiographic eHOA was associated with elevated levels of interleukin-7 (risk ratio (RR) per SD = 1.30 [95% confidence interval (CI) 1.09, 1.55] p trend 0.01). CONCLUSION: This exploratory study suggests an association of elevated interleukin-7, an inflammatory cytokine, with incident eHOA, while other cytokines or biomarkers of metabolic inflammation were not associated. Interleukin-7 may mediate inflammation and tissue damage in susceptible osteoarthritic finger joints and participate in erosive progression.

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

PURPOSE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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 OF EVIDENCE: Level IV, cases series subgroup analysis.

Terminal knee extension deficit and female sex predict poorer quadriceps strength following ACL reconstruction using all-soft tissue quadriceps tendon autografts.

PURPOSE: The all-soft tissue quadriceps tendon (QT) autograft is becoming increasingly popular for ACL reconstruction (ACLR); however, studies reporting strength recovery and early outcomes after QT autograft are limited with patient samples composed of predominantly males. The primary purpose was to characterize early, sex-specific recovery of strength, range of motion (ROM), and knee laxity in a large cohort of patients undergoing primary ACLR with standardized harvest technique of the all-soft tissue QT autograft. The secondary purpose was to examine the influence of demographic factors and clinical measures on 6-month quadriceps strength. METHODS: Patients 14-25 years who underwent primary, unilateral ACLR with all-soft tissue QT autografts were prospectively followed. Knee laxity and ROM were collected at 6 weeks, 3 and 6 months; while, quadriceps normalized torques and limb symmetry indices (LSI) were collected at 3 and 6 months using isokinetic dynamometry at 60°/s. Two-way ANOVAs with repeated measures were conducted to determine recovery over time and between sexes. Stepwise linear multiple regressions were conducted to determine predictors of 6-month quadriceps strength. RESULTS: Three-hundred and twenty patients were included (18 ± 3 years; 156 males:164 females; BMI = 24 ± 4 kg/m2) with no early graft failures within the study period. For strength, there were significant main effects of time (p < 0.001) and sex (p < 0.001), indicating similar improvement from 3 to 6 months with males demonstrating greater quadriceps LSI (6 months: 72.1 vs 63.3%) and normalized strength (6 months: 2.0 vs 1.6 Nm/kg). A significantly higher proportion of females had knee extension ROM deficits ≥ 5° compared to males at 6 weeks (61 vs 39%; p = 0.002). Female sex and 3-month extension ROM deficits were identified as significant predictors of 6-month quadriceps LSI (R2 = 0.083; p < 0.001). Female sex, BMI, and 6-week extension ROM deficits were identified as significant predictors of 6-month normalized quadriceps strength (R2 = 0.190; p < 0.001). CONCLUSIONS: Females had decreased quadriceps strength and greater extension ROM deficits at 3 and 6 months following ACLR using all-soft tissue QT autografts. Female sex, higher BMI, and loss of extension ROM were independent predictors of poorer quadriceps strength at 6 months. There were no early graft failures, and laxity remained within normal ranges for both males and females. Surgeons and rehabilitation clinicians should be aware of the increased risk of postoperative loss of extension ROM in females and its implications on quadriceps strength recovery. LEVEL OF EVIDENCE: III.

Editorial Commentary: Considering Fatigue When Assessing Athletes for Dynamic Knee Valgus: Is This the Next Big Step in Identifying Anterior Cruciate Ligament Injury Risk?

Excessive dynamic knee valgus during jumping is a poor movement strategy that has been well-documented as a risk factor for anterior cruciate ligament injury. Yet, there has been little progress in the translation of findings from high-tech motion capture laboratories to clinically applicable settings. One barrier to widespread use is expensive technology that requires time; therefore, field-based efficient assessment tools that can be used by several types of clinicians are desperately needed. Further, fatigue can influence dynamic knee valgus and should be considered when assessing or conditioning athletes.

Liposomal Bupivacaine and Ropivacaine Adductor Canal Blocks for Anterior Cruciate Ligament Reconstruction Provide Similar Postoperative Analgesia.

The purpose of this study was to compare postoperative pain following anterior cruciate ligament (ACL) reconstruction (ACLR) in patients receiving an adductor canal block (ACB) with ropivacaine (R-ACB) or liposomal bupivacaine (LB-ACB). The secondary purpose was to compare opioid consumption. A prospective cohort study of patients undergoing ACLR at an academic medical center was conducted from November 1, 2018 to November 21, 2019. The first cohort received R-ACB and 30 tablets of 5/325 mg oxycodone/acetaminophen. After June 13, 2019, the second cohort received LB-ACB and 20 tablets of 5/325 mg oxycodone/acetaminophen with the reduction in opioids prescribed resulting from a hospital quality improvement initiative to decrease narcotic consumption. From postoperative days 0 through 6, pain was assessed thrice daily using a numeric rating scale. Total postoperative opioid consumption was reported via tablet count and converted to oral morphine equivalents (OMEs). During this period, 165 subjects underwent ACLR, and 126 met the eligibility criteria (44.4% female, 55.6% male; mean ± standard deviation: 28.7 ± 13.7 years). Sixty-six (52.4%) received LB-ACB, and 60 (47.6%) received R-ACB (p = 0.53). The most common graft utilized was quadriceps autograft (63.6% LB-ACB; 58.3% R-ACB, p = 0.76). Mean postoperative pain scores were similar between groups during the entire postoperative period (p ≥ 0.08 for POD 0-6). While postoperative opioid consumption was lower among patients receiving LB-ACB (median OME [interquartile range]: 28.6 [7.5-63.8] vs. 45.0 [15.0-75.0], p = 0.023), this only amounted to an average of 2.2 tablets. Patients receiving LB-ACB in the setting of ACLR reported similar postoperative pain compared with those receiving R-ACB. Despite the second aim of our study, we cannot make conclusions about the effect of each block on opioid consumption given that each cohort received different numbers of opioid tablets due to institutional pressure to reduce opioid prescribing. As few patients completed their opioid prescriptions or requested refills, further reduction in prescription size is warranted. Future studies are necessary to further elucidate the effect of LB-ACB versus R-ACB on postoperative pain and opioid consumption after ACLR.

Associations of Strength and Spatiotemporal Gait Variables With Knee Loading During Gait After Anterior Cruciate Ligament Reconstruction.

CONTEXT: Altered knee moments are common during gait in patients after anterior cruciate ligament reconstruction (ACLR). Modifiable factors that influence knee moments and are feasible to record in clinical settings such as strength and spatiotemporal values (eg, step length, step width) have not been identified in persons after ACLR. OBJECTIVE: To identify strength and spatiotemporal gait values that can predict knee moments in persons after ACLR. DESIGN: Cross-sectional study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Twenty-three individuals with ACLR (14.4 ± 17.2 months post-ACLR). MAIN OUTCOME MEASURE(S): Peak knee-flexion and -adduction moments were measured while the participants walked at self-selected speeds. Peak isokinetic knee-extensor strength (60°/s) was recorded on a dynamometer, and spatiotemporal gait values were recorded using a pressure walkway. Pearson coefficients were calculated to examine the association of peak knee moments with strength and gait values. Variables correlated with peak knee-flexion and -adduction moments were entered into a stepwise regression model. RESULTS: Knee-extensor strength and step width were the strongest predictors of knee-flexion moment, accounting for 44% of the variance, whereas stance-phase time and step width were the strongest predictors of knee-adduction moment, explaining 62% of the variance. CONCLUSIONS: The identified spatiotemporal variables could be clinically feasible targets for biofeedback to improve gait after ACLR.

Detection of Meniscal Tear Effects on Tibial Vibration Using Passive Knee Sound Measurements.

OBJECTIVE: To evaluate whether non-invasive knee sound measurements can provide information related to the underlying structural changes in the knee following meniscal tear. These changes are explained using an equivalent vibrational model of the knee-tibia structure. METHODS: First, we formed an analytical model by modeling the tibia as a cantilever beam with the fixed end being the knee. The knee end was supported by three lumped components with features corresponding with tibial stiffnesses, and meniscal damping effect. Second, we recorded knee sounds from 46 healthy legs and 9 legs with acute meniscal tears (n = 34 subjects). We developed an acoustic event ("click") detection algorithm to find patterns in the recordings, and used the instrumental variable continuous-time transfer function estimation algorithm to model them. RESULTS: The knee sound measurements yielded consistently lower fundamental mode decay rate in legs with meniscal tears ( 16 ±13 s - 1) compared to healthy legs ( 182 ±128 s - 1), p < 0.05. When we performed an intra-subject analysis of the injured versus contralateral legs for the 9 subjects with meniscus tears, we observed significantly lower natural frequency and damping ratio (first mode results for healthy: [Formula: see text]injured: [Formula: see text]) for the first three vibration modes (p < 0.05). These results agreed with the theoretical expectations gleaned from the vibrational model. SIGNIFICANCE: This combined analytical and experimental method improves our understanding of how vibrations can describe the underlying structural changes in the knee following meniscal tear, and supports their use as a tool for future efforts in non-invasively diagnosing meniscal tear injuries.

Integrated 3D motion analysis with functional magnetic resonance neuroimaging to identify neural correlates of lower extremity movement.

BACKGROUND: To better understand the neural drivers of aberrant motor control, methods are needed to identify whole brain neural correlates of isolated joints during multi-joint lower-extremity coordinated movements. This investigation aimed to identify the neural correlates of knee kinematics during a unilateral leg press task. NEW METHOD: The current study utilized an MRI-compatible motion capture system in conjunction with a lower extremity unilateral leg press task during fMRI. Knee joint kinematics and brain activity were collected concurrently and averaged range of motion were modeled as covariates to determine the neural substrates of knee out-of-plane (frontal) and in-plane (sagittal) range of motion. RESULTS: Increased out-of-plane (frontal) range of motion was associated with altered brain activity in regions important for attention, sensorimotor control, and sensorimotor integration (z >3.1, p < .05), but no such correlates were found with in-plane (sagittal) range of motion (z >3.1, p > .05). Comparison with Existing Method(s): Previous studies have either presented overall brain activation only, or utilized biomechanical data collected outside MRI in a standard biomechanics lab for identifying single-joint neural correlates. CONCLUSIONS: The study shows promise for the MRI-compatible system to capture lower-extremity biomechanical data collected concurrently during fMRI, and the present data identified potentially unique neural drivers of aberrant biomechanics. Future research can adopt these methods for patient populations with CNS-related movement disorders to identify single-joint kinematic neural correlates that may adjunctively supplement brain-body therapeutic approaches.

Identification of strength and spatiotemporal gait parameters associated with knee loading during gait in persons after anterior cruciate ligament reconstruction.

CONTEXT: Altered knee moments are common during gait in patients following anterior cruciate ligament reconstruction (ACLR). Modifiable factors that influence knee moments and are feasible to record in clinical settings such as strength and spatiotemporal parameters (e.g. step length, step width) have not been identified in persons after ACLR. OBJECTIVE: The objective was to identify strength and spatiotemporal gait parameters that can predict knee moments in persons after ACLR. DESIGN: Cross-Sectional Study Setting: Laboratory Patients: Twenty-three participants with ACLR (14.4 ± 17.2 months post-ACLR) participated. MAIN OUTCOME MEASURES: Peak knee flexion and adduction moments were measured while walking at self-selected speeds. Spatiotemporal gait parameters were recorded with a pressure walkway, and peak isokinetic knee extensor strength (60°/s) was recorded on a dynamometer. Pearson coefficients were used to examine the association of peak knee moments with strength and gait parameters. Variables correlated with peak knee flexion and adduction moments were entered into a stepwise regression model. RESULTS: Step width and knee extensor strength were the strongest predictors of knee flexion moment accounting for 44% of data variance, whereas stance phase time and step width were the strongest predictors of knee adduction moment explaining 62% of data variance. CONCLUSIONS: The spatiotemporal variables that were identified could be clinically feasible targets for biofeedback to improve gait after ACLR.

An Interpretable Experimental Data Augmentation Method to Improve Knee Health Classification Using Joint Acoustic Emissions.

The characteristics of joint acoustic emissions (JAEs) measured from the knee have been shown to contain information regarding underlying joint health. Researchers have developed methods to process JAE measurements and combined them with machine learning algorithms for knee injury diagnosis. While these methods are based on JAEs measured in controlled settings, we anticipate that JAE measurements could enable accessible and affordable diagnosis of acute knee injuries also in field-deployable settings. However, in such settings, the noise and interference would be greater than in sterile, laboratory environments, which could decrease the performance of existing knee health classification methods using JAEs. To address the need for an objective noise and interference detection method for JAE measurements as a step towards field-deployable settings, we propose a novel experimental data augmentation method to locate and then, remove the corrupted parts of JAEs measured in clinical settings. In the clinic, we recruited 30 participants, and collected data from both knees, totaling 60 knees (36 healthy and 24 injured knees) to be used subsequently for knee health classification. We also recruited 10 healthy participants to collect artifact and joint sounds (JS) click templates, which are audible, short duration and high amplitude JAEs from the knee. Spectral and temporal features were extracted, and clinical data was augmented in five-dimensional subspace by fusing the existing clinical dataset into experimentally collected templates. Then knee scores were calculated by training and testing a linear soft classifier utilizing leave-one-subject-out cross-validation (LOSO-CV). The area under the curve (AUC) was 0.76 for baseline performance without any window removal with a logistic regression classifier (sensitivity = 0.75, specificity = 0.78). We obtained an AUC of 0.86 with the proposed algorithm (sensitivity = 0.80, specificity = 0.89), and on average, 95% of all clinical data was used to achieve this performance. The proposed algorithm improved knee health classification performance by the added information through identification and collection of common artifact sources in JAE measurements. This method when combined with wearable systems could provide clinically relevant supplementary information for both underserved populations and individuals requiring point-of-injury diagnosis in field-deployable settings.

Implications for Early Postoperative Care After Quadriceps Tendon Autograft for Anterior Cruciate Ligament Reconstruction: A Technical Note.

The quadriceps tendon (QT) has become increasingly used by orthopaedic surgeons as an alternative autograft choice in anterior cruciate ligament reconstruction. As its use increases, athletic trainers and other rehabilitation clinicians will treat a greater number of patients with this autograft type. The recently developed, minimally invasive technique for harvest of the all-soft tissue autograft has many benefits, including versatility, decreased donor-site morbidity, and enhanced cosmesis. Early clinical trials revealed that the QT autograft resulted in decreased anterior knee pain and similar strength and functional outcomes to those of more common autograft types. From a rehabilitation perspective, many characteristics should be considered, such as the importance of early knee extension and quadriceps activation. Therefore, the purpose of this technical note is to expose athletic trainers to the QT autograft so that they may provide the best care for patients after anterior cruciate ligament reconstruction.

Quadriceps Neuromuscular and Physical Function After Anterior Cruciate Ligament Reconstruction.

CONTEXT: Persistent neuromuscular deficits in the surgical limb after anterior cruciate ligament reconstruction (ACLR) have been repeatedly described in the literature, yet little is known regarding their association with physical performance and patient-reported function. OBJECTIVE: To describe (1) interlimb differences in neuromuscular and functional outcomes and (2) the associations of neuromuscular outcomes with measures of physical and knee-related patient-reported function. DESIGN: Cross-sectional study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Thirty individuals after primary, unilateral ACLR (19 males; age = 21.5 years [range, 14-41 years]; 8 months [range = 6-23 months] postsurgery). MAIN OUTCOME MEASURE(S): Knee-extensor isometric and isokinetic peak torque was measured with an isokinetic dynamometer. Cross-sectional area (CSA) was measured bilaterally for each of the quadriceps muscles via magnetic resonance imaging. We measured quadriceps central activation bilaterally via the superimposed-burst technique. Physical performance (single-legged hop tests, step length via spatiotemporal gait analysis) and patient-reported outcomes (International Knee Documentation Committee questionnaire and Knee Injury and Osteoarthritis Outcome Score Sport and Recreation subscale) were also recorded. We conducted Wilcoxon signed rank tests to identify interlimb differences. Spearman ρ correlation analyses revealed associations between limb symmetry and neuromuscular and functional outcomes, as well as with patient-reported function. RESULTS: Deficits in the surgical limb as compared with the nonsurgical limb were present for all outcomes (P values < .05). Greater single-legged hop-test symmetry (83%) was significantly correlated with greater symmetry in knee-extensor isometric (63%; rs = 0.567, P = .002) and isokinetic (68%; rs = 0.540, P = .003) strength, as well as greater cross-sectional area of the vastus medialis (78%; rs = 0.519, P = .006) and vastus lateralis (82%; rs = 0.752, P < .001). A higher International Knee Documentation Committee questionnaire score (82.2) was significantly correlated with greater symmetry in knee-extensor isokinetic strength (rs = 0.379, P = .039). CONCLUSIONS: Although deficits were observed in the surgical limb for all neuromuscular measures, greater symmetry in the size and strength of the quadriceps, rather than activation, was more strongly associated with physical performance after ACLR. Greater symmetry in strength was also more strongly associated with patient-reported function.

Systematic Review of Publications Regarding Quadriceps Tendon Autograft Use in Anterior Cruciate Ligament Reconstruction.

PURPOSE: To perform a systematic review with quantitative and qualitative analysis of publications to date focusing on the use of quadriceps tendon (QT) autografts in anterior cruciate ligament (ACL) reconstruction and to define the regional variability, type of publication, level of evidence, journal of publication, and type of QT graft used. METHODS: The PubMed, Scopus, and Google Scholar databases were systematically queried for journal articles relating to QT autografts used for ACL reconstruction through 2018. These publications were filtered for relevance and then analyzed and differentiated by publication characteristics. RESULTS: Most articles were published in the United States and Europe, and most articles evaluating clinical outcomes were Level of Evidence III. Over 60% of the publications (115 of 187) focusing on QT for ACL reconstruction were published within the past 10 years, and 30% (56 of 187) were published within the past 3 years. The results not only showed a recent increase in the number of publications regarding QT as a choice for the autograft harvest site in ACL reconstruction over time, but also yielded informative data regarding the publication journal, country or region, and level of evidence. CONCLUSIONS: This evaluation shows the increasing interest in the scientific evaluation of QT as a source of autograft tissue for ACL reconstruction. CLINICAL RELEVANCE: Increased production of high-quality research will allow surgeons to feel more confident in their use of the QT as an autograft option in ACL reconstruction.

Quadriceps Recovery After Anterior Cruciate Ligament Reconstruction With Quadriceps Tendon Versus Patellar Tendon Autografts.

BACKGROUND: Quadriceps tendon (QT) autografts are being increasingly used for anterior cruciate ligament reconstruction (ACLR). A paucity of studies exist that compare QT autografts with alternative graft options. Additionally, concerns exist regarding quadriceps recovery after graft harvest insult to the quadriceps muscle-tendon unit. PURPOSE/HYPOTHESIS: The purpose of this study was to compare quadriceps recovery and functional outcomes in patients with QT versus bone-patellar tendon-bone (BPTB) autografts. The hypothesis was that those with QT autografts would demonstrate superior outcomes. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Active patients with a history of primary, unilateral ACLR with soft tissue QT or BPTB autografts participated. Quadriceps recovery was quantified using variables of strength, muscle size, and activation. Knee extensor isometric and isokinetic strength was measured bilaterally with an isokinetic dynamometer and normalized to body weight. Quadriceps activation was measured with the superimposed burst technique. The maximal cross-sectional area of each quadriceps muscle was measured bilaterally using magnetic resonance imaging. Assessors of muscle size were blinded to the graft type and side of ACLR. Functional tests included hop tests and step length symmetry during walking, measured via spatiotemporal gait analysis. Self-reported function was determined with the International Knee Documentation Committee (IKDC) questionnaire. Neuromuscular and functional outcomes were expressed as limb symmetry indices (LSIs: [surgical limb/nonsurgical limb]*100%). Wilcoxon rank-sum tests were used to compare the LSIs and IKDC scores between groups. RESULTS: There were 30 study participants (19 male, 11 female; median age, 22 years [range, 14-41 years]; median time since surgery, 8 months [range, 6-23 months]), with 15 patients in each group. There were no significant between-group differences in demographic variables or outcomes. LSIs were not significantly different between the QT versus BPTB group, respectively: knee extensor isokinetic strength at 60 deg/s (median, 70 [range, 41-120] vs 68 [range, 37-83]; P = .285), activation (median, 95 [range, 85-111] vs 92 [range, 82-105]; P = .148), cross-sectional area of the vastus medialis (median, 79 [range, 62-104] vs 77 [range, 62-95]; P = .425), single-leg hop test (median, 88 [range, 35-114] vs 77 [range, 49-100]; P = .156), and step length symmetry (median, 99 [range, 93-104] vs 98 [range, 92-103]; P = .653). The median IKDC scores between the QT and BPTB groups were also not significantly different: 82 (range, 67-94) versus 83 (range, 54-94); respectively (P = .683). CONCLUSION: Patients with QT autografts demonstrated similar short-term quadriceps recovery and postsurgical outcomes compared with patients with BPTB autografts.

KOOS-JR Demonstrates Psychometric Limitations in Measuring Knee Health in Individuals After ACL Reconstruction.

BACKGROUND: Measurement properties of the short form of the Knee injury and Osteoarthritis Outcome Score (KOOS-JR) are not established in individuals after anterior cruciate ligament reconstruction (ACLR). The purpose of this study was to determine the extent to which the KOOS-JR measures the construct of knee health in individuals post-ACLR using Rasch analysis. HYPOTHESIS: The KOOS-JR will fit the Rasch model, but significant ceiling effects will be present. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: Rasch analysis of the KOOS-JR from 166 individuals 10 months post-ACLR was conducted. Unidimensionality, a key criterion of the Rasch model, was evaluated using confirmatory factor analysis. Model fit of the rating scale, items, and persons were evaluated. Mean square fit statistics ≥1.6 and standardized z-scores ≥2.0 were indicative of person or item misfit. Additionally, reliability indicators including person reliability and separation indices were examined. RESULTS: The KOOS-JR fit the criteria of unidimensionality. All items demonstrated model fit; however, ceiling effects were noted (n = 36; 22%). Person reliability was low (0.47). Calculation of person strata revealed that the KOOS-JR did not separate participants into more than 1 stratum. The mean person measure was 3.56 logits higher than the mean item measure, indicating that this sample is skewed toward increased knee health. CONCLUSION: Although the KOOS-JR represented a unidimensional construct with items and persons fitting the Rasch model, several limitations were noted: ceiling effects, low person reliability, and poor person differentiation. Ceiling effects indicate that many individuals in this sample experienced better knee health than the KOOS-JR items were able to measure. CLINICAL RELEVANCE: Evaluating the measurement properties of the KOOS-JR is necessary to determine its clinical value in sports medicine. In later stages after ACLR recovery, administration of the KOOS-JR may not be adequate.

Skeletal muscle changes following stroke: a systematic review and comparison to healthy individuals.

BACKGROUND: Despite extensive study of the impact of stroke on muscle and functional performance, questions remain regarding the extent to which changes are due to the neurological injury vs. age-related loss of morphology and force production. OBJECTIVES: To synthesize available evidence describing post-stroke changes in lower extremity muscle size and strength compared to healthy adults. METHODS: Scientific literature was searched up to April 2016 to identify studies that included lower extremity muscle size and strength measures in individuals with chronic stroke. Lower extremity muscle size and strength data from healthy controls were sought for comparison. Relative differences were calculated between paretic, nonparetic, and control limbs. RESULTS: Fifteen studies with 375 participants (61% male; age = 62 ± 5 years; time since stroke = 60 ± 42 months) were included. The paretic limb exhibited deficits of ~13% in thigh muscle size, ~5% in lower leg muscle size, and ~8% in lean leg mass compared to the nonparetic limb. Paretic plantarflexor and knee extensor strength were 52 and 36% lower, respectively, compared to the nonparetic limb. When compared to age-matched control data, both paretic and nonparetic limbs showed deficits in muscle size and strength. CONCLUSIONS: Age-related differences support the impact of stroke-related sarcopenia as a contributor to hemiparetic muscle dysfunction. Understanding these muscular changes is necessary for designing appropriate exercise interventions aimed at restoring muscle function.

POWER training in chronic stroke individuals: differences between responders and nonresponders.

BACKGROUND: Lower extremity muscle weakness is a primary contributor to post-stroke dysfunction. Resistance training is an effective treatment for hemiparetic weakness and improves walking performance. Post-stroke subject characteristics that do or do not improve walking speed following resistance training are unknown. OBJECTIVE: The purpose of this paper was to describe baseline characteristics, as well as responses to training, associated with achieving a minimal clinically important difference (MCID) in walking speed (≥0.16 m/s) following Post-stroke Optimization of Walking Using Explosive Resistance (POWER) training. METHODS: Seventeen participants completed 24 sessions of POWER training, which included intensive progressive leg presses, jump training, calf raises, sit-to-stands, step-ups, and over ground fast walking. Outcomes included SSWS, FCWS, DGI, FMA-LE, 6-MWT, paretic knee power, non-paretic knee power, and paretic step ratio. RESULTS: Specific to those who reached MCID in SSWS (e.g. "responders"), significant improvements in SSWS, FCWS, 6-MWT, paretic knee power, and non-paretic knee power was realized. Paretic knee power and non-paretic knee power significantly improved in those who did not achieve MCID for gait speed (e.g. "non-responders"). CONCLUSION: The potential for POWER training to enhance general locomotor function was confirmed. Baseline paretic knee strength/power may be an important factor in how an individual responds to this style of training. The lack of change within the non-responders emphasizes the contribution of factors other than lower extremity muscle power improvement to locomotor dysfunction.

The Effects of POWER Training in Young and Older Adults after Stroke.

Background. Approximately 35,000 strokes occur annually in adults below the age of 40, and there is disappointingly little data describing their responses to rehabilitation. The purpose of this analysis was to determine the effects of Poststroke Optimization of Walking using Explosive Resistance (POWER) training in young (<40 years) and older (>60 years) adults and to describe relationships between training-induced improvements in muscular and locomotor function. Methods. Data was analyzed from 16 individuals with chronic stroke who participated in 24 sessions of POWER training. Outcomes included muscle power generation, self-selected walking speed (SSWS), 6-minute walk test, Fugl-Meyer motor assessment, Berg Balance Scale, and Dynamic Gait Index. Results. There were no significant differences between groups at baseline. Within-group comparisons revealed significant improvements in paretic and nonparetic knee extensor muscle power generation in both groups. Additionally, young participants significantly improved SSWS. Improvements in SSWS were more strongly associated with improvements in power generation on both sides in young versus older participants. Conclusions. Younger adults after stroke seem to preferentially benefit from POWER training, particularly when increasing gait speed is a rehabilitation goal. Future research should aim to further understand age-related differences in response to training to provide optimal treatments for all individuals following stroke.

Progesterone Inhibits basal and gonadotropin-releasing hormone induction of luteinizing hormone beta-subunit gene expression.

LH and FSH play critical roles in mammalian reproduction by mediating steroidogenesis and gametogenesis in the gonad. Gonadal steroid hormone feedback to the hypothalamus and pituitary influences production of the gonadotropins. We previously demonstrated that progesterone differentially regulates the expression of the LH and FSH beta-subunits at the level of the gonadotrope: FSHbeta transcription is induced, whereas LHbeta is repressed. In this study, we investigated the mechanism of progesterone repression of LHbeta gene expression using immortalized gonadotrope-derived LbetaT2 cells. The progesterone suppression of both basal and GnRH-induced LHbeta gene expression occurs in a hormone- and receptor-dependent manner. Chromatin immunoprecipitation demonstrates that the hormone-bound progesterone receptor (PR) is recruited to the endogenous mouse LHbeta promoter. In addition, suppression requires both the amino-terminal and DNA-binding regions of PR. Furthermore, progesterone suppression does not require direct PR binding to the promoter, and, thus, PR is likely recruited to the promoter via indirect binding through other transcription factors. These data demonstrate that the molecular mechanism for progesterone action on the LHbeta promoter is distinct from FSHbeta, which involves direct PR binding to the promoter to produce activation. It also differs from androgen repression of LHbeta gene expression in that, rather than Sp1 or steroidogenic factor-1 elements, it requires elements within -300/-250 and -200/-150 that also contribute to basal expression of the LHbeta promoter. Altogether, our data indicate that progesterone feedback at the level of the pituitary gonadotrope is likely to play a key role in differential production of the gonadotropin genes.