The Relationship Between Patient Expectations and Functional Outcomes in Patients Undergoing Cartilage Repair of the Knee: A Mixed Methods Study.

CONTEXT: Patient expectations have been shown to be a major predictor of outcomes. Fulfilled expectations have been linked to increased patient satisfaction and rehabilitation adherence. Expectations may be influenced by a variety of factors, including patient characteristics, preoperative function, or disease characteristics. It is currently unknown what factors may influence patient expectations prior to cartilage repair of the knee, and to what degree. Furthermore, understanding the importance and values of those expectations for recovery using mixed methods has not previously been conducted in this patient population. The purpose of this mixed methods study is to examine and explore the relationships between patient expectations and functional outcome in patients undergoing cartilage repair of the knee. DESIGN: A mixed methods design was used. METHODS: Twenty-one patients scheduled to undergo cartilage repair of the knee were included. Participants completed the Hospital for Special Surgery Knee Surgery Expectations Survey and the Knee Injury and Osteoarthritis Outcome Score at their preoperative visit. Knee Injury and Osteoarthritis Outcome Scores were also obtained at 3 and 6 months postsurgery. A selected sample of 6 participants participated in semi-structured interviews 6 months postsurgery. Pearson correlation coefficients were used to determine relationships between expectations and functional outcome. RESULTS: Patients have moderate expectations for recovery, and these expectations were positively associated with preoperative pain, activities of daily living, and quality of life. Expectations also correlated with symptoms 3 months postsurgery, but there were no other significant correlations between preoperative expectations and postoperative function in the short term. Four qualitative themes emerged as participants described how previous recovery experiences shaped their expectations. CONCLUSIONS: Formalized patient and caregiver education, prehabilitation, and the use of psychological skills during rehabilitation may help to manage patient expectations and provide more focused and individualized care, thus improving outcomes.

Low Self-Efficacy and High Kinesiophobia Are Associated With Worse Function in Patients With Femoroacetabular Impingement Syndrome.

CONTEXT: Femoroacetabular impingement syndrome (FAIS) is a painfully debilitating hip condition disproportionately affecting active individuals. Mental health disorders are an important determinant of treatment outcomes for individuals with FAIS. Self-efficacy, kinesiophobia, and pain catastrophizing are psychosocial factors that have been linked to inferior outcomes for a variety of orthopedic conditions. However, these psychosocial factors and their relationships with mental health disorders, pain, and function have not been examined in individuals with FAIS. OBJECTIVE: (1) To examine relationships between self-efficacy, kinesiophobia, pain catastrophizing, pain, and function in patients with FAIS and (2) to determine if these variables differ between patients with and without a self-reported depression and/or anxiety. DESIGN: Cross-sectional. SETTING: University health center. PARTICIPANTS: Fifty-one individuals with FAIS (42 females/9 males; age 35.7 [11.6] y; body mass index 27.1 [4.9] kg/m2). MAIN OUTCOME MEASURES: Participants completed the Pain Self-Efficacy Questionnaire, Tampa Scale for Kinesiophobia, Pain Catastrophizing Scale, visual analog scale for hip pain at rest and during activity, and the 12-item International Hip Outcome Tool. Self-reported depression and/or anxiety were recorded. The relationships between psychosocial factors, pain, and function were examined using Spearman rank-order correlations. Independent t tests and Mann-Whitney U tests were used to evaluate the effect of self-reported depression and/or anxiety on psychosocial factors, pain and function. RESULTS: The 12-item International Hip Outcome Tool was correlated with pain during activity (ρ = -.57, P ≤ .001), Tampa Scale for Kinesiophobia (ρ = -.52, P ≤ .001), and Pain Self-Efficacy Questionnaire (ρ = .71, P ≤ .001). The Pain Self-Efficacy Questionnaire was also correlated with pain at rest (ρ = -.43, P = .002) and pain during activity (ρ = -.46, P = .001). Individuals with self-reported depression and/or anxiety (18/51; 35.3%) had worse self-efficacy and pain catastrophizing (P ≤ .01). CONCLUSION: Self-reported depression and/or anxiety, low self-efficacy, and high kinesiophobia were associated with more hip pain and worse function for patients with FAIS. These findings warrant further examination including psychosocial treatment strategies to improve the likelihood of a successful clinical outcome for this at-risk population.

Relationship Between Pain Catastrophizing and 6-Month Outcomes Following Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Pain catastrophizing predicts poor outcomes following orthopedic procedures for patients with chronic conditions; however, limited research has focused on acute injuries. This study aimed to quantify the progression of Pain Catastrophizing Scale (PCS) scores from injury to 6-months post-anterior cruciate ligament reconstruction (ACLR) and determine if preoperative or 6-month PCS scores were related with self-reported pain or function 6 months post-ACLR. The authors hypothesized PCS scores would minimally fluctuate and would be related with worse outcomes 6-months post-ACLR. METHODS: All 48 participants (27 male/21 female; aged 22.7 [4.6] y, body mass index 24 [3.3]) included in this secondary analysis of a randomized control trial sustained an ACL injury during sports activity. Participants completed the PCS and Pain Visual Analog Scale (VAS) at 5 time points: within 7 days of injury (INITIAL), day of surgery, 2 weeks postoperative (2W), 6 weeks postoperative (6W), and 6 months postoperative (6M). They completed the Knee Injury and Osteoarthritis Outcome Score (KOOS) at 6M. Wilcoxon signed-rank tests and Spearman rank-order correlations were used for analysis. RESULTS: PCS scores were not fixed (INITIAL: 11.6 [10.8], day of surgery: 2.5 [3.7], 2W: 8.0 [7.8], 6W: 3.7 [6], 6M: 0.8 [2.3]). They fluctuated in response to injury and ACLR similar to Pain VAS scores. Preoperative PCS scores were not related with 6M outcomes; however, 6M PCS scores were significantly related with 6M Pain VAS and KOOS subscales. CONCLUSIONS: PCS scores fluctuated in response to injury and ACLR. Preoperative PCS scores were not related with 6M outcomes; however, 6M PCS scores correlated with pain and function at 6M. High pain catastrophizing appears to be a natural response immediately following acute ACL injury and ACLR, but may not be indicative of a poor postoperative result. PCS scores 6-months following ACLR may provide useful information regarding self-reported pain and function.

Repeated Impacts Diminish the Impact Performance of Equestrian Helmets.

Context: During thoroughbred races, jockeys are placed in potentially injurious situations, often with inadequate safety equipment. Jockeys frequently sustain head injuries; therefore, it is important that they wear appropriately certified helmets. Objective: The goals of this study are (1) to perform impact attenuation testing according to ASTM F1163-15 on a sample of equestrian helmets commonly used by jockeys in the United States and (2) to quantify headform acceleration and residual crush after repeat impacts at the same location. Participants and Design: Seven helmet models underwent impact attenuation testing according to ASTM F1163-15. A second sample of each helmet model underwent repeat impacts at the crown location for a total of 4 impacts. Setting: Laboratory. Intervention: Each helmet was impacted against a flat and equestrian hazard anvil. Main Outcome Measures: Headform acceleration was recorded during all impact and computed tomography scans were performed preimpact and after impacts 1 and 4 on the crown to quantify liner thickness. Results: Four helmets had 1 impact that exceeded the limit of 300g. During the repeated crown impacts, acceleration remained below 300g for the first and second impacts for all helmets, while only one helmet remained below 300g for all impacts. Foam liner thickness was reduced between 5% and 39% after the first crown impact and between 33% and 70% after the fourth crown impact. Conclusions: All riders should wear a certified helmet and replace it after sustaining a head impact. Following an impact, expanded polystyrene liners compress, and their ability to attenuate head acceleration during subsequent impacts to the same location is reduced. Replacing an impacted helmet may reduce a rider's head injury risk.

Comparison of Transcutaneous Electrical Nerve Stimulation and Cryotherapy for Increasing Quadriceps Activation in Patients With Knee Pathologies.

CLINICAL SCENARIO: Proper neuromuscular activation of the quadriceps muscle is essential for maintaining quadriceps (quad) strength and lower-extremity function. Quad activation (QA) failure is a common characteristic observed in patients with knee pathologies, defined as an inability to voluntarily activate the entire alpha-motor-neuron pool innervating the quad. One of the more popular techniques used to assess QA is the superimposed burst (SIB) technique, a force-based technique that uses a supramaximal, percutaneous electrical stimulation to activate all of the motor units in the quad during a maximal, voluntary isometric contraction. Central activation ratio (CAR) is the formula used to calculate QA level (CAR = voluntary force/SIB force) with the SIB technique. People who can voluntarily activate 95% or more (CAR = 0.95-1.0) of their motor units are defined as being fully activated. Therapeutic exercises aimed at improving quad strength in patients with knee pathologies are limited in their effectiveness due to a failure to fully activate the muscle. Within the past decade, several disinhibitory interventions have been introduced to treat QA failure in patients with knee pathologies. Transcutaneous electrical nerve stimulation (TENS) and cryotherapy are sensory-targeted modalities traditionally used to treat pain, but they have been shown to be 2 of the most successful treatments for increasing QA levels in patients with QA failure. Both modalities are hypothesized to positively affect voluntary QA by disinhibiting the motor-neuron pool of the quad. In essence, these modalities provide excitatory afferent stimuli to the spinal cord, which thereby overrides the inhibitory afferent signaling that arises from the involved joint. However, it remains unknown whether 1 is more effective than the other for restoring QA levels in patients with knee pathologies. By knowing the capabilities of each disinhibitory modality, clinicians can tailor treatments based on the rehabilitation goals of their patients. Focused Clinical Question: Is TENS or cryotherapy the more effective disinhibitory modality for treating QA failure (quantified via CAR) in patients with knee pathologies?

Quadriceps and Hamstring Strength Recovery During Early Neuromuscular Rehabilitation After ACL Hamstring-Tendon Autograft Reconstruction.

CONTEXT: There is lack of information related to quadriceps and hamstring strength recovery during the early period of rehabilitation after anterior cruciate ligament reconstruction (ACLR) using hamstring-tendon graft (HTG). OBJECTIVE: To investigate quadriceps and hamstring isometric strength at 4-, 8-, and 12-wk time points after ACLR and to document the strength changes of these muscles over time. DESIGN: Longitudinal study. PARTICIPANTS: 24 patients (age 28.1 ± 8.1 y) who underwent unilateral single-bundle anatomic ACLR with 4-strand semitendinosus and gracilis tendon graft. MAIN OUTCOME MEASURES: The isometric strength of quadriceps and hamstring muscles was measured on an isokinetic dynamometer at a 60° knee-flexion angle 4, 8, and 12 wk after surgery. RESULTS: Quadriceps and hamstring strength significantly increased over time for both the involved limb (quadriceps F2,46 = 58.3, P < .001; hamstring F2,46 = 35.7, P < .001) and uninvolved limb (quadriceps F2,46 = 17.9, P < .001; hamstring F2,46 =56.9, P = .001). Quadriceps and hamstring indexes significantly changed from 4 wk (QI 57.9, HI 54.4) to 8 wk (QI 78.8, HI 69.9) and from 8 wk to 12 wk (QI 82, HI 75.7) (P < .001); however, there was no difference between indexes at the 12-wk time point (P = .17). CONCLUSIONS: The results of this study serve as a reference for clinicians while directing a rehabilitation protocol for HTG ACLR patients to better appreciate expected strength changes of the muscles in the early phase of recovery.

Comparison of isokinetic hip abduction and adduction peak torques and ratio between sexes.

OBJECTIVE: To evaluate hip abductor and adductor peak torque outputs and compare their ratios between sexes. DESIGN: A cross-sectional laboratory-controlled study. SETTING: Participants visited a laboratory and performed an isokinetic hip abductor and adductor test. All participants performed 2 sets of 5 repetitions of concentric hip abduction and adduction in a standing position at 60 degrees per second. Gravity was determined as a function of joint angle relative to the horizontal plane and was corrected by normalizing the weight of the limb on an individual basis. PARTICIPANTS: A total of 36 collegiate athletes. INDEPENDENT VARIABLES: Sex (20 females and 16 males). MAIN OUTCOME MEASURES: Bilateral peak hip abductor and adductor torques were measured. The 3 highest peak torque values were averaged for each subject. RESULTS: Independent t tests were used to compare sex differences in hip abductor and adductor peak torques and the abductor:adductor peak torque ratios. Males demonstrated significantly greater hip abductor peak torque compared with females (males 1.29 ± 0.24 Nm/kg, females 1.13 ± 0.20 Nm/kg; P = 0.03). Neither hip adductor peak torque nor their ratios differed between sexes. CONCLUSIONS: Sex differences in hip abductor strength were observed. The role of weaker hip abductors in females deserves further attention and may be a factor for higher risk of knee pathologies.

Influence of response shift on early patient-reported outcomes following autologous chondrocyte implantation.

PURPOSE: Response shift is the phenomenon by which an individual's standards for evaluation change over time. The purpose of this study was to determine whether patients undergoing autologous chondrocyte implantation (ACI) experience response shift. METHODS: Forty-eight patients undergoing ACI participated. The "then-test" method was used to evaluate response shift in commonly used patient-reported outcome measures (PROMs)-the SF-36 Physical Component Scale (SF-36 PCS), WOMAC, IKDC, and Lysholm. Each PROM was completed pre- and 6 and 12 months post-surgery. At 6 and 12 months, an additional "then" version of each form was also completed. The "then" version was identical to the original except that patients were instructed to assess how they were prior to ACI. Traditional change, response shift adjusted change, and response shift magnitude were calculated at 6 and 12 months. T tests (p < 0.05) were used to compare traditional change to response-shift-adjusted change, and response shift magnitude values to previously established minimal detectable change. RESULTS: There were no differences between traditional change and response-shift-adjusted change for any of the PROMs. The mean response shift magnitude value of the WOMAC at 6 months (15 ± 14, p = 0.047) was greater than the previously established minimal detectable change (10.9). The mean response shift magnitude value for the SF-36 PCS at 12 months (9.4 ± 6.8, p = 0.017) also exceeded the previously established minimal detectable change (6.6). CONCLUSIONS: There was no evidence of a group-level effect for response shift. These results support the validity of pre-test/post-test research designs in evaluating treatment effects. However, there is evidence that response shifts may occur on a patient-by-patient basis, and scores on the WOMAC and SF-36 in particular may be influenced by response shift. LEVEL OF EVIDENCE: II.

Effect of gender on the quadriceps-to-hamstrings coactivation ratio during different exercises.

CONTEXT: Coactivation ratio of quadriceps to hamstring muscles (Q:H) and medial to lateral knee muscles (M:L) contributes to the dynamic stability of the knee joint during movement patterns recommended during rehabilitation and important for daily function. OBJECTIVE: To compare the quadriceps-to-hamstring and medial-to-lateral knee muscles' coactivation ratios between men and women during the following closed kinetic chain exercises performed on a balance board: forward lunge, side lunge, single-leg stance, and single-leg squat. DESIGN: Cross-sectional. PARTICIPANTS: 20 healthy subjects (10 female and 10 male). MAIN OUTCOME MEASURES: Surface electromyography was used to measure the activation level of quadriceps (vastus lateralis and medialis) and hamstrings (biceps femoris and medial hamstrings) during forward- and side-lunge, single-leg-stance, and single-leg-squat exercises. Subjects were instructed during each exercise to move into the test position and to hold that position for 15 s. EMG was recorded during the 15-s isometric period where subjects tried to maintain a "set" position while the foot was on a balance board. Analysis of variance was used for statistical analysis. RESULTS: There was a significant exercise-by-gender interaction for Q:H ratio (F3,48 = 6.63, P = .001), but the exercise-by-gender interaction for M:L ratio was not significant (F3,48 = 1.67, P = .18). Women showed larger Q:H ratio in side-lunge exercises than men (P = .002). Both genders showed larger M:L and lower Q:H ratio in a single-leg-stance exercise than in the other exercises. CONCLUSIONS: The results indicate that the forward- and side-lunge and single-leg-squat exercises should not be recommended as exercise where a balanced coactivation between quadriceps and hamstring muscles is warranted. Single-leg-stance exercise could be used when seeking an exercise where the ratio is balanced for both women and men.

Patient-oriented and performance-based outcomes after knee autologous chondrocyte implantation: a timeline for the first year of recovery.

CONTEXT: It is well established that autologous chondrocyte implantation (ACI) can require extended recovery postoperatively; however, little information exists to provide clinicians and patients with a timeline for anticipated function during the first year after ACI. OBJECTIVE: To document the recovery of functional performance of activities of daily living after ACI. PATIENTS: ACI patients (n = 48, 29 male; 35.1 ± 8.0 y). INTERVENTION: All patients completed functional tests (weight-bearing squat, walk-across, sit-to-stand, step-up/over, and forward lunge) using the NeuroCom long force plate (Clackamas, OR) and completed patient-reported outcome measures (International Knee Documentation Committee Subjective Knee Evaluation Form, Lysholm, Western Ontario and McMaster Osteoarthritis Index [WOMAC], and 36-Item Short-Form Health Survey) preoperatively and 3, 6, and 12 mo postoperatively. MAIN OUTCOME MEASURES: A covariance pattern model was used to compare performance and self-reported outcome across time and provide a timeline for functional recovery after ACI. RESULTS: Participants demonstrated significant improvement in walk-across stride length from baseline (42.0% ± 8.9% height) at 6 (46.8% ± 8.1%) and 12 mo (46.6% ± 7.6%). Weight bearing on the involved limb during squatting at 30°, 60°, and 90° was significantly less at 3 mo than presurgery. Step-up/over time was significantly slower at 3 mo (1.67 ± 0.69 s) than at baseline (1.49 ± 0.33 s), 6 mo (1.51 ± 0.36 s), and 12 mo (1.40 ± 0.26 s). Step-up/over lift-up index was increased from baseline (41.0% ± 11.3% body weight [BW]) at 3 (45.0% ± 11.7% BW), 6 (47.0% ± 11.3% BW), and 12 mo (47.3% ± 11.6% BW). Forward-lunge time was decreased at 3 mo (1.51 ± 0.44 s) compared with baseline (1.39 ± 0.43 s), 6 mo (1.32 ± 0.05 s), and 12 mo (1.27 ± 0.06). Similarly, forward-lunge impact force was decreased at 3 mo (22.2% ± 1.4% BW) compared with baseline (25.4% ± 1.5% BW). The WOMAC demonstrated significant improvements at 3 mo. All patient-reported outcomes were improved from baseline at 6 and 12 mo postsurgery. CONCLUSIONS: Patients' perceptions of improvements may outpace physical changes in function. Decreased function for at least the first 3 mo after ACI should be anticipated, and improvement in performance of tasks requiring weight-bearing knee flexion, such as squatting, going down stairs, or lunging, may not occur for a year or more after surgery.

Effect of a 2-week joint mobilization intervention on single-limb balance and ankle arthrokinematics in those with chronic ankle instability.

CONTEXT: A single talocrural joint-mobilization treatment has improved spatiotemporal measures of postural control but not ankle arthrokinematics in individuals with chronic ankle instability (CAI). However, the effects of multiple treatment sessions on these aspects of function have not been investigated. OBJECTIVE: To examine the effect of a 2-wk anterior-to-posterior joint-mobilization intervention on instrumented measures of single-limb-stance static postural control and ankle arthrokinematics in adults with CAI. DESIGN: Repeated measures. SETTING: Research laboratory. PARTICIPANTS: 12 individuals with CAI (6 male, 6 female; age 27.4 ± 4.3 y, height 175.4 ± 9.78 cm, mass 78.4 ± 11.0 kg). INTERVENTION: Subjects received 6 treatments sessions of talocrural grade II joint traction and grade III anterior-to-posterior joint mobilization over 2 wk. MAIN OUTCOME MEASURES: Instrumented measures of single-limb-stance static postural control (eyes open and closed) and anterior and posterior talar displacement and stiffness were assessed 1 wk before the intervention (baseline), before the first treatment (preintervention), 24-48 h after the final treatment (postintervention), and 1 wk later (1-wk follow-up). Postural control was analyzed as center-of-pressure velocity, center-of-pressure range, the mean of time-to-boundary minima, and standard deviation of time-to-boundary minima in the anteroposterior and mediolateral directions for each visual condition. RESULTS: No significant differences were identified in any measures of postural control (P > .08) or ankle arthrokinematics (P > .21). CONCLUSIONS: The 2-wk talocrural joint-mobilization intervention did not alter instrumented measures of single-limb-stance postural control or ankle arthrokinematics. Despite the absence of change in these measures, this study continues to clarify the role of talocrural joint mobilization as a rehabilitation strategy for patients with CAI.

Understanding the effects of a sudden directional shift in somatosensory feedback and increasing task complexity on postural adaptation in individuals with and without chronic ankle instability.

BACKGROUND: Individuals with chronic ankle instability (CAI) present somatosensory dysfunction following an initial ankle sprain. However, little is known about how individuals with CAI adapt to a sudden sensory perturbation of instability with increasing task and environmental constraints to maintain postural stability. METHODS: Forty-four individuals with and without unilateral CAI performed the Adaptation Test to a sudden somatosensory inversion and plantarflexion perturbations (environment) in double-, injured-, and uninjured- limbs. Mean sway energy scores were analyzed using 2 (group) × 2 (somatosensory perturbations) × 3 (task) repeated measures analysis of variance. RESULTS: There were significant interactions between the group, environment, and task (P=.025). The CAI group adapted faster than healthy controls to a sudden somatosensory inversion perturbation in the uninjured- (P=.002) and injured- (P<.001) limbs, as well as a sudden somatosensory plantarflexion perturbation in the double- (P=.033) and uninjured- (P=.035) limbs. The CAI and healthy groups presented slower postural adaptation to a sudden inversion perturbation than a sudden somatosensory plantarflexion perturbation in double-limb (P<.001). Whereas both groups demonstrated faster postural adaptation to a sudden somatosensory inversion perturbation compared to somatosensory plantarflexion perturbation while maintaining posture in the injured- (P<.001) and uninjured- (P<.001) limbs. The CAI and healthy groups adapted faster to a sudden somatosensory inversion perturbation in the injured- (P<.001) and uninjured- (P<.001) limbs than in double-limb, respectively. DISCUSSION: Postural adaptation in individuals with and without CAI depended on environmental (somatosensory perturbations) and task constraints. The CAI group displayed comparable and faster postural adaptation to a sudden somatosensory inversion and plantarflexion in double-, injured-, and uninjured- limbs, which may reflect a centrally mediated alteration in neuromuscular control in CAI.

Preoperative Temporal Summation is Associated with Impaired Recovery Following Hip Arthroscopy for Femoroacetabular Impingement Syndrome .

Objectives: Chronic pain is a risk factor for worse outcomes following hip arthroscopy for femoroacetabular impingement syndrome (FAIS). Pain sensitization involves the central nervous system perceiving previously innocuous stimuli as noxious. Temporal summation can provide a surrogate measure of sensitization, and may be a clinical tool to identify patients at a higher risk for poor post-hip arthroscopy outcomes. Therefore, we aimed to 1) identify the prevalence of temporal summation in patients undergoing hip arthroscopy for FAIS, 2) determine if there a difference in postoperative improvement between individuals with and without preoperative temporal summation, and 3) examine preoperative predictors of poor postoperative recovery. Methods: 51 participants undergoing hip arthroscopy for FAIS underwent preoperative temporal summation testing. Three months postoperatively, 38 participants completed the 12-item International Hip Outcome Tool (iHOT-12) and reported their overall symptomatic improvement (0% to 100%, with 100% being normal). Participants were categorized on the presence ( Numeric Pain Rating Scale; NPRS   2) or absence (  NPRS < 2) of temporal summation. A Mann-Whitney U test was used to determine the difference in improvement between groups (temporal summation: temporal summation (TS), no temporal summation (NTS), and a linear regression was used to explore predictors of improvement. Results: 23 (45.1%) of 51 participants displayed preoperative temporal summation. In participants with postoperative data, those with temporal summation reported less improvement than those without (TS: 62.8%   29.7%; NTS: 82.7%   13.9%; p = 0.01; Cohen's d = -0.86). Temporal summation (Beta = -0.48; 95% CI -36.6, -8.7) and mental health disorder (Beta = -0.30; 95% CI -28.0, -0.48) predicted 28.1% of the variance in postoperative improvement (p = 0.002). Conclusion: The presence of preoperative temporal summation is common and related to worse postoperative recovery after hip arthroscopy for FAIS.

Targeting quadriceps inhibition with electromyographic biofeedback: a neuroplastic approach.

Weakness of the quadriceps is a common occurrence in patients after knee injury or surgery; this weakness is due to a natural mechanism known as arthrogenic muscle inhibition. If inhibition of the quadriceps persists, it can become detrimental to a patient's function and lead to additional pathologies. A number of therapeutic interventions have be used in the rehabilitation of these patients, but few have proven to be successful. Electromyographic biofeedback is one modality that has demonstrated positive outcomes in patients by restoring quadriceps function. However, the reason for the effectiveness of this modality has yet to be fully explained in the area of rehabilitation. Neuroplasticity is a phenomenon that has gained much attention in rehabilitation, and its potential continues to grow. After an injury, the brain has the ability to enhance recovery by strengthening its neural circuitry. Through rehabilitation, clinicians can use attentional strategies to foster neuroplasticity and promote the recovery of their patients. In this article we provide reasoning for the effectiveness of electromyographic biofeedback using the evidence of neuroplasticity. With this information, we hope to provide clinicians a rationale for using this tool in the rehabilitation of patients with persistent quadriceps inhibition.

Self-perceptions of proximal stability as measured by the functional movement screen.

This mixed method study was designed to investigate self-perceptions before and after experiencing an activity that dynamically and statically challenges proximal stability of the pelvis, spine, and trunk. Twenty-eight, healthy Division II female soccer and volleyball collegiate players (17 soccer, 11 volleyball) completed a self-reported Tegner activity scale, pretest questionnaire and posttest interview. A self-perceived numeric rating of the athletes' proximal stability and performance on a functional movement screen (FMS) were recorded. A guided interview was used to examine the self-perceptions of proximal stability after the FMS testing session. Differences and correlations between the pretest and posttest ratings of proximal stability and FMS scores were analyzed using a 1-sample Kolmogorov-Smirnov test and Spearman's rank order correlation test, respectively. Residual standard error from a 1-way analysis of variance was used to explore the association between variables. Qualitative data were recorded and transcribed. There were significant differences between the pretest (3.4 ± 0.63) and posttest ratings (3.1 ± 0.49) of proximal stability (p = 0.01). The relationship between the pretest proximal stability ratings and the FMS scores was low (r = 0.19, p = 0.33), whereas posttest rating and FMS scores had a moderately high (r = 0.68, p = 0.00) correlation. There was a smaller residual standard error for the posttest ratings (1.7) when compared with the pretest ratings (3.2) with the FMS. Four qualitative themes emerged: (a) wanting to do well, (b) expectations of performance, (c) focused mental mindset, and (d) body control. Self-perceptions of proximal stability in female athletes were influenced by undergoing a test that stressed the proximal stabilizers. Combining assessments of self-perceptions and proximal stability may assist clinicians and athletes in targeting components of training.

Test-retest reliability and validity of isometric knee-flexion and -extension measurement using 3 methods of assessing muscle strength.

CONTEXT: Physicians and clinicians need portable, efficient, and cost-effective assessment tools to determine the effectiveness of rehabilitation programs after knee injury. Progress in rehabilitation should be evaluated using valid and reliable measurement methods. OBJECTIVE: To examine the test-retest reliability of portable fixed dynamometry (PFD), handheld dynamometry (HHD), and isokinetic dynamometry (IKD). In addition, the authors sought to examine the validity of PFD and HHD by comparing differences in peak torque of the knee flexors and extensors to that of the "gold standard" IKD. DESIGN: Repeated measures. PARTICIPANTS: 16 healthy subjects (age 29.3 ± 7.2 y, height 167.4 ± 8.04 cm, mass 73.7 ± 20.0 kg). MAIN OUTCOME MEASURES: The dependent variables were peak torque (normalized to body weight) of the knee flexors and extensors; the independent variables were trial (trial 1, trial 2) and instrument (IKD, PFD, and HHD). RESULTS: Test-retest reliability was high for both PFD and IKD. However, fair to poor reliability was found for HHD. There were no differences in peak torque (Nm) between IKD and PFD. However, significant differences in peak torque were observed between IKD and HHD and between PFD and HHD. CONCLUSIONS: PFD provides reliable measures of strength and also demonstrates similar output measures as IKD. Its portability, ease of use, and cost provide clinicians an effective means of measuring strength.

Sensory Reweighting System Differences on Vestibular Feedback with Increased Task Constraints in Individuals with Chronic Ankle Instability Compared to Healthy Controls.

CONTEXT: Chronic ankle instability (CAI) is associated with a less flexibly adaptable sensorimotor system. Thus, individuals with CAI may present an inadequate sensory reweighting system inhibiting the ability to emphasize weight on reliable sensory feedback to control posture. However, how individuals with CAI reweight sensory feedback to maintain postural control in bilateral and unilateral stances has yet to be established. OBJECTIVES: The primary purpose was to examine group differences in how the sensory reweighting system changes to control posture in a simple double-limb stance and a more complex single-limb stance (uninjured-limb, injured-limb) under increased environmental constraints manipulating somatosensory and visual information for individuals with and without CAI. The secondary purpose was to examine the effect of environmental and task constraints on postural control. STUDY DESIGN: Case-control study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: 21 individuals with CAI (26.4±5.7years, 171.2±9.8cm, 76.6±15.17kg) and 21 healthy controls (25.8±5.7years, 169.5±9.5cm, 72.4±15.0kg) participated in the study. MAIN OUTCOME MEASURE(S): Equilibrium10 were examined while completing 6 environmental conditions of the Sensory Organization Test (SOT) during 3 tasks (double-limb and single-limb [uninjured, injured] stances). Sensory reweighting ratios for sensory systems (somatosensory, vision, vestibular) were computed from paired Equilibrium10. RESULTS: Significant 3-factor interactions were found between group, sensory systems, and tasks (P=0.006) and for groups, task, and environment (P=0.007). The CAI group failed to downweight vestibular feedback compared to healthy controls while maintaining posture in the injured-limb (P=0.030). The CAI group displayed better postural stability than healthy controls while standing with absent vision, fixed surroundings, and a moving platform in the injured-limb (P=0.032). CONCLUSIONS: The CAI group relied on vestibular feedback while maintaining better postural stability than healthy controls in the injured-limb. Group differences in postural control depended on both environmental (absent vision, moving platform) and task (injured-limb) constraints.

Reliability of video motion-analysis systems to measure amplitude and velocity of shoulder elevation.

CONTEXT: Dynamic shoulder motion can be captured using video capture systems, but reliability has not yet been established. OBJECTIVE: To compare the reliability of 2 systems in measuring dynamic shoulder kinematics during forward-elevation movements and to determine differences in these kinematics between healthy and injured subjects. DESIGN: Reliability and cohort. SETTING: Research laboratory. PARTICIPANTS: 11 healthy subjects and 10 post-superior labrum anteroposterior lesion patients (SLAP). INTERVENTION: Contrasting markers were placed at the hip, elbow, and shoulder to represent shoulder elevation and were videotaped in 2 dimensions. Subjects performed 6 repetitions of active elevation (AE) and active assisted elevation of the shoulder, and 3 trials were analyzed using Datapac (comprehensive system) and Dartfish (basic system). MAIN OUTCOME MEASURES: Amplitudes and velocities of the shoulder angle were calculated. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), and levels of agreement (LOA) were used to determine intersystem and intertrial reliability. RESULTS: For AE, the amplitude maximum (ICC = .98-.99, SEM = 2-3°, LOA = -9° to 5°) and average velocity (ICC = .94-.97, SEM = 1°/s, LOA = -4° to 1°/s) indicated excellent intersystem reliability between systems. Intratrial reliability for minimum velocity was moderate for Datapac (ICC = .64, SEM = 4°/s, LOA = 7°/s) and poor for Dartfish (ICC = .52, SEM = 20°/s, LOA = 37°/s). Cohort results demonstrated for AE a greater amplitude for healthy v SLAP (139° ± 11° v 113° ± 13°; P = .001) and interaction for an average velocity increase of 2°/s in healthy and decrease of 2°/s in SLAP patients over the 3 trials (P = .02). CONCLUSIONS: Reliability ranges provide the means to assess the clinical meaningfulness of results. The cohort differences are supported when the values exceed the ranges of the SEM; hence the amplitude results are meaningful. For dynamic shoulder elevation measured using video, the assessment of velocity was found to produce moderate to good reliability. The results suggest that with these measures subtle changes in both measures may be possible with further investigations.

A Comparison of Neuromuscular Electrical Stimulation Parameters for Postoperative Quadriceps Strength in Patients After Knee Surgery: A Systematic Review.

CONTEXT: Postoperative quadriceps strength weakness after knee surgery is a persistent issue patients and health care providers encounter. OBJECTIVE: To investigate the effect of neuromuscular electrical stimulation (NMES) parameters on quadriceps strength after knee surgery. DATA SOURCES: CINAHL, MEDLINE, SPORTDiscus, and PubMed were systematically searched in December 2018. STUDY SELECTION: Studies were excluded if they did not assess quadriceps strength or if they failed to report the NMES parameters or quadriceps strength values. Additionally, studies that applied NMES to numerous muscle groups or simultaneously with other modalities/treatments were excluded. Study quality was assessed with the Physiotherapy Evidence Database (PEDro) scale for randomized controlled trials. STUDY DESIGN: Systematic review. LEVEL OF EVIDENCE: Level 1. DATA EXTRACTION: Treatment parameters for each NMES treatment was extracted for comparison. Quadriceps strength means and standard deviations were extracted and utilized to calculate Hedge g effect sizes with 95% CIs. RESULTS: Eight RCTs were included with an average Physiotherapy Evidence Database scale score of 5 ± 2. Hedge g effect sizes ranged from small (-0.37; 95% CI, -1.00 to 0.25) to large (1.13; 95% CI, 0.49 to 1.77). Based on the Strength of Recommendation Taxonomy Quality of Evidence table, the majority of the studies included were low quality RCTs categorized as level 2: limited quality patient-oriented evidence. CONCLUSION: Because of inconsistent evidence among studies, grade B evidence exists to support the use of NMES to aid in the recovery of quadriceps strength after knee surgery. Based on the parameters utilized by studies demonstrating optimal treatment effects, it is recommended to implement NMES treatment during the first 2 postoperative weeks at a frequency of ≥50 Hz, at maximum tolerable intensity, with a biphasic current, with large electrodes and a duty cycle ratio of 1:2 to 1:3 (2- to 3-second ramp).