How Does Physical and Psychological Recovery Vary Among Competitive and Recreational Athletes After Anterior Cruciate Ligament Reconstruction?

BACKGROUND: The recovery and rehabilitation journey after anterior cruciate ligament reconstruction (ACLR) surgery can be different for competitive and recreational athletes as their motivation and goals toward sports are different. HYPOTHESIS: Competitive athletes would present with better patient-reported outcomes and higher muscle strength compared with recreational athletes postsurgery. Second, competitive athletes would recover better (patient-reported outcome [PRO] measures and muscle strength) compared with recreational athletes at later stages. STUDY DESIGN: Cross-sectional laboratory-based study. LEVEL OF EVIDENCE: Level 2. METHODS: A total of 245 patients with unilateral ACLR were categorized as competitive or recreational athletes and grouped into early (4-6.9 months) or late (7-10 months) stages of recovery. PRO were collected for psychological response (Tampa Scale Kinesiophobia; Anterior Cruciate Ligament-Return to Sport after Injury), perceived knee function (International Knee Documentation Committee subjective form [IKDC]), and quality of life (Knee injury and Osteoarthritis Outcome Score; Veteran Rand-12). Isokinetic, concentric knee extension strength was measured bilaterally with a multimodal dynamometer (System 4, Biodex Medical Systems) at a speed of 90° and 180°/s. RESULTS: Competitive athletes had significantly higher scores for IKDC (P = 0.03), and quadriceps peak torque at 90°/s (P = 0.01) and 180°/s (P < 0.01) compared with recreational athletes. Competitive athletes had higher quadriceps strength at 90°/s (P < 0.01) and 180°/s (P = 0.02) in the late group. Recreational athletes displayed higher sports participation in the late group. CONCLUSION: Outcomes of ACLR may differ based on preinjury athletic level. Whereas competitive athletes had higher knee and muscle function than recreational athletes, psychological measures were not different among groups. CLINICAL RELEVANCE: There is a need for more individualized care for patients with ACLR since there is variability among patient goals postsurgery. This information might help set realistic expectations for competitive and recreational athletes after surgery.

Automated Versus Traditional Scoring Agreeability During the Balance Error Scoring System.

CONTEXT: The Balance Error Scoring System (BESS) is a commonly used clinical tool to evaluate postural control that is traditionally performed through visual assessment and subjective evaluation of balance errors. The purpose of this study was to evaluate an automated computer-based scoring system using an instrumented pressure mat compared to the traditional human-based manual assessment. DESIGN: A descriptive cross-sectional study design was used to evaluate the performance of the automated versus human BESS scoring methodology in healthy individuals. METHODS: Fifty-one healthy active participants performed BESS trials following standard BESS procedures on an instrumented pressure mat (MobileMat, Tekscan Inc). Trained evaluators manually scored balance errors from frontal and sagittal plane video recordings for comparison to errors scored using center of force measurements and an automated scoring software (SportsAT, version 2.0.2, Tekscan Inc). A linear mixed model was used to determine measurement discrepancies across the 2 methods. Bland-Altman analyses were conducted to determine limit of agreement for the automated and manual scoring methods. RESULTS: Significant differences between the automated and manual errors scored were observed across all conditions (P < .05), excluding bilateral firm stance. The greatest discrepancy between scoring methods was during the tandem foam stance, while the smallest discrepancy was during the tandem firm stance. CONCLUSION: The 2 methods of BESS scoring are different with wide limits of agreement. The benefits and risks of each approach to error scoring should be considered when selecting the most appropriate metric for clinical use or research studies.

Influence of Graft Type and Meniscal Involvement on Short-Term Outcomes Following Anterior Cruciate Ligament Reconstruction.

CONTEXT: The purpose of this study was to compare short-term clinical outcomes between meniscus procedures performed with anterior cruciate ligament reconstruction (ACLR), ACLR (ACLR-only), ACLR with meniscectomy/resection (ACLR-resect), and ACLR with meniscal repair (ACLR-repair) for bone patellar tendon bone grafts (BPTB) and hamstring tendon grafts, separately. DESIGN: This was a cross-sectional study conducted in a controlled laboratory setting as part of a large point-of-care collaborative research program. METHODS: This study included 314 participants (168 females; mean [SD]: age, 19.7 [4.8]) with primary unilateral ACLR with a BPTB or hamstring tendon. Patients were divided into 3 groups depending on meniscal procedure (ACLR-only, ACLR-resect, and ACLR-repair). Postsurgical testing included: isokinetic assessment of knee extension and flexion, single-leg hop tests, and patient-reported outcomes. Multivariate analysis of covariance compared differences between meniscal procedures on the battery of tests, and for each statistically significant variable an analysis of covariance assessed the effect of meniscal procedure within each graft type. Chi-square analysis assessed the influence of meniscal procedure on tests' pass rates defined as 90% of limb symmetry index. RESULTS: BPTB: ACLR-only had greater hamstring strength than ACLR-resect (P = .05) and ACLR-repair (P = .005). ACLR-only had the highest proportion of participants to pass the hamstring strength test (P = .02). Hamstring tendon: ACLR-only (P = .03) and ACLR-resect (P = .003) had higher International Knee Documentation Committee scale scores than ACLR-repair. There was a significant difference in the proportion of participants who scored >90% limb symmetry index on the timed hop test (P = .05). CONCLUSIONS: The influence of meniscal repair on clinical outcomes is dependent on the graft choice. Following an ACLR with BPTB and a meniscal procedure, hamstring function should be more closely monitored for optimal short-term recovery.

The Effect of Exercise on a Novel Dual-Task Assessment for Sport Concussion.

PURPOSE: This study aimed to determine the effect of exercise on cognitive and motor performance and the subsequent test-retest reliability of a novel dual-task (DT) assessment in nonconcussed college students. METHODS: Sixty nonconcussed college students (53.3% female) with an average age (±SD) of 20.5 ± 1.34 yr, height of 171.7 ± 9.33 cm, and mass of 69.3 ± 12.23 kg were included in the study. Participants were assigned to an exercise ( n = 30) or rest ( n = 30) intervention group and completed two study visits that were separated by a 2-wk test-retest interval. At each visit, participants completed a novel DT assessment that consisted of the concurrent administration of the Standardized Assessment of Concussion (SAC) and tandem gait (TG) before the exercise or rest intervention. After the DT assessment at the first visit, participants in the exercise group performed moderate-intensity exercise, whereas the rest group sat quietly for 30 min. After the intervention, both groups were readministered the DT assessment. At the second visit, the same procedures were followed, except that each group was administered the opposite intervention (e.g., the exercise group completed the rest intervention). A composite TG (cTG) score was calculated by summing the average time to complete the TG pattern during each SAC domain (immediate memory, digits backwards, months in reverse order, delayed recall). An ANCOVA was conducted to assess postintervention differences while controlling for preintervention performance. Test-retest reliability was assessed using intraclass correlation coefficients (ICC 3,2 ) with 95% confidence intervals, with all analyses performed with α = 0.05. RESULTS: SAC and cTG performance was similar ( P values > 0.05) from preintervention to postintervention for the rest or exercise protocols. Good (rest: ICC = 0.77 (0.62-0.87); exercise: ICC = 0.84 (0.73-0.90)) and excellent (rest: ICC = 0.97 (0.94-0.98); exercise: ICC = 0.93 (0.88-0.96)) test-retest reliabilities were observed for the SAC composite score and cTG score, respectively. CONCLUSIONS: Our DT assessment was robust to the influence of moderate-intensity exercise and demonstrated good-to-excellent test-retest reliability in a healthy collegiate sample.

Longitudinal Changes in Quadriceps Morphology over the First 3 Months after Anterior Cruciate Ligament Reconstruction.

PURPOSE: Neuromuscular deficits and atrophy after anterior cruciate ligament reconstruction (ACLR) may be accompanied by changes in muscle composition and poor quadriceps muscle quality (QMQ). Quadriceps atrophy occurs after ACLR but improves within the first three postoperative months, yet this hypertrophy could be attributable to increases in noncontractile tissue (i.e., poor QMQ). The purposes of this study were to evaluate changes in QMQ after ACLR and to determine if changes in QMQ and cross-sectional area (CSA) occur in parallel or independently. METHODS: A longitudinal prospective cohort design was implemented to evaluate QMQ and CSA in 20 individuals with ACLR and 12 healthy controls. Participants completed three testing sessions (baseline/presurgery, 1 month, and 3 months) during which ultrasound images were obtained from the vastus lateralis (VL) and rectus femoris (RF). QMQ was calculated as the echo intensity (EI) of each image, with high EI representing poorer QMQ. Anatomical CSA was also obtained from each image. RESULTS: RF and VL EI were greater at 1 and 3 months in the ACLR limb compared with baseline and the contralateral limb and did not change between 1 and 3 months. VL and RF CSA in the ACLR limb were smaller at 1 and 3 months compared with the contralateral limb and controls (VL only) but increased from 1 to 3 months. Changes in QMQ and CSA were not correlated. CONCLUSIONS: QMQ declines within the first month after ACLR and does not improve by 3 months although hypertrophy occurs, suggesting that these morphological characteristics change independently after ACLR. Poorer QMQ represents greater concentration of noncontractile tissues within the muscle and potentially contributes to chronic quadriceps dysfunction observed after ACLR.

Knee extensor torque-velocity relationships following anterior cruciate ligament reconstruction.

BACKGROUND: The 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. METHODS: 681 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. FINDINGS: There 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). INTERPRETATION: Following 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.

Hip Strength Recovery After Anterior Cruciate Ligament Reconstruction.

Background: Return-to-play (RTP) assessment after anterior cruciate ligament reconstruction (ACLR) rarely includes hip strength. Hypothesis: It was hypothesized that (1) patients after ACLR will have weaker hip abduction (AB) and adduction (AD) strength compared with the contralateral limb, with larger deficits in women, (2) there will be a correlation between hip and thigh strength ratios and patient-reported outcomes (PROs), and (3) hip AB and AD strength will improve over time. Study Design: Descriptive laboratory study. Methods: Included were 140 patients (74 male, 66 female; mean age, 24.16 ± 10.82 years) who underwent RTP assessment at 6.1 ± 1.6 months after ACLR; 86 patients underwent a second assessment at 8.2 ± 2.2 months. Hip AB/AD and knee extension/flexion isometric strength were measured and normalized to body mass, and PRO scores were collected. Strength ratios (hip vs thigh), limb differences (injured vs uninjured), sex-based differences, and relationships between strength ratios and PROs were determined. Results: Hip AB strength was weaker on the ACLR limb (ACLR vs contralateral: 1.85 ± 0.49 vs 1.89 ± 0.48 N·m/kg; P < .001) and hip AD torque was stronger (ACLR vs contralateral: 1.80 ± 0.51 vs 1.76 ± 0.52 N·m/kg; P = .004), with no sex-by-limb interaction found. Lower hip-to-thigh strength ratios of the ACLR limb were correlated with higher PRO scores (r = -0.17 to -0.25). Over time, hip AB strength increased in the ACLR limb more than in the contralateral limb (P = .01); however, the ACLR limb remained weaker in hip AB at visit 2 (ACLR vs contralateral: 1.88 ± 0.46 vs 1.91 ± 0.45 N·m/kg; P = .04). In both limbs, hip AD strength was greater at visit 2 than visit 1 (ACLR: 1.82 ± 0.48 vs 1.70 ± 0.48 N·m/kg; contralateral: 1.76 ± 0.47 vs 1.67 ± 0.47 N·m/kg; P < .01 for both). Conclusion: The ACLR limb had weaker hip AB and stronger AD compared with the contralateral limb at initial assessment. Hip muscle strength recovery was not influenced by sex. Hip strength and symmetry improved over the course of rehabilitation. Although strength differences across limbs were minor, the clinical importance of these differences is still unknown. Clinical Relevance: The evidence provided highlights the need to integrate hip strength into RTP assessments to identify hip strength deficits that may increase reinjury or lead to poor long-term outcomes.

Comparison of Patient-Reported Outcomes, Strength, and Functional Performance in Primary Versus Revision Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Clinical outcomes after revision anterior cruciate ligament reconstruction (ACLR) are not well understood. HYPOTHESIS: Patients undergoing revision ACLR would demonstrate worse patient-reported outcomes and worse limb symmetry compared with a cohort undergoing primary ACLR. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: 672 participants (373 with primary ACLR, 111 with revision ACLR, and 188 uninjured) completed functional testing at a single academic medical center. Descriptive information, operative variables, and patient-reported outcomes (International Knee Documentation Committee score, Knee injury and Osteoarthritis Outcome Score, and Tegner Activity Scale score) were assessed for each patient. Quadriceps and hamstring strength tests were conducted using a Biodex System 3 Dynamometer. Single-leg hop for distance, triple hop test, and the 6-m timed hop test were also assessed. Limb symmetry index (LSI) between the ACLR limb and contralateral limb was calculated for strength and hop testing. Normalized peak torque (N·m/kg) was calculated for strength testing. RESULTS: No differences were found in group characteristics, excluding body mass (P < .001), or in patient-reported outcomes. There were no interactions between revision status, graft type, and sex. Knee extension LSI was inferior (P < .001) in participants who had undergone primary (73.0% ± 15.0%) and revision (77.2% ± 19.1%) ACLR compared with healthy, uninjured participants (98.8% ± 10.4%). Knee flexion LSI was inferior (P = .04) in the primary group (97.4% ± 18.4%) compared with the revision group (101.9% ± 18.5%). Difference in knee flexion LSI between the uninjured and primary groups, as well as between the uninjured and revision groups, did not reach statistical significance. Hop LSI outcomes were significantly different across all groups (P < .001). Between-group differences in extension in the involved limb (P < .001) were noted, as the uninjured group exhibited stronger knee extension (2.16 ± 0.46 N·m/kg) than the primary group (1.67 ± 0.47 N·m/kg) and the revision group (1.78 ± 0.48 N·m/kg). As well, differences in flexion in the involved limb (P = .01) were found, as the revision group exhibited stronger knee flexion (1.06 ± 0.25 N·m/kg) than the primary group (0.97 ± 0.29 N·m/kg) and the uninjured group (0.98 ± 0.24 N·m/kg). CONCLUSION: At 7 months postoperatively, patients who had undergone revision ACLR did not demonstrate inferior patient-reported outcomes, limb symmetry, strength, or functional performance compared with patients who had undergone primary ACLR. Patients who had undergone revision ACLR exhibited greater strength and LSI than their counterparts with primary ACLR, but these parameters were still inferior to those of uninjured controls.

A Deep Learning Algorithm for Automatic 3D Segmentation of Rotator Cuff Muscle and Fat from Clinical MRI Scans.

The authors aimed to develop and validate an automated artificial intelligence (AI) algorithm for three-dimensional (3D) segmentation of all four rotator cuff (RC) muscles to quantify intramuscular fat infiltration (FI) and individual muscle volume. The dataset included retrospectively collected RC MRI scans in 232 patients (63 with normal RCs, 169 with RC tears). A two-stage AI model was developed to segment all RC muscles and their FI in each stage. For comparison, single-stage and Otsu filtering models were created. Using the two-stage model, segmentation performance demonstrated high Dice scores (mean, 0.92 ± 0.14 [SD]), low volume errors (mean, 5.72% ± 9.23), and low FI errors (mean, 1.54% ± 2.79) when validated in 30 scans. There was a significant correlation between the 3D FI in the RC tear scans with a Goutallier grade (ρ = 0.53, P < .001) and FI found from a single two-dimensional (2D) section (all muscles, ρ > 0.70; P < .001). However, Bland-Altman analysis of the 3D compared with the 2D analyses of FI demonstrated a proportional bias (all muscles, P < .001). Compared with Goutallier classification or single-image quantification, the AI method allowed for more variability in images and led to objective separate quantifications of muscle volume and FI in all RC muscles. Keywords: Rotator Cuff, Artificial Intelligence, Segmentation, Fat Infiltration, Muscle Volume, MRI, Shoulder Supplemental material is available for this article. © RSNA, 2023.

Reservoir computing with noise.

This paper investigates in detail the effects of measurement noise on the performance of reservoir computing. We focus on an application in which reservoir computers are used to learn the relationship between different state variables of a chaotic system. We recognize that noise can affect the training and testing phases differently. We find that the best performance of the reservoir is achieved when the strength of the noise that affects the input signal in the training phase equals the strength of the noise that affects the input signal in the testing phase. For all the cases we examined, we found that a good remedy to noise is to low-pass filter the input and the training/testing signals; this typically preserves the performance of the reservoir, while reducing the undesired effects of noise.

Influence of interim functional assessments on patient outcomes at the time of return to activity following ACL-reconstruction.

OBJECTIVE: To compare patient outcomes at the time of the return to activity (RTA) progression between those with a prior interim assessment and those without. DESIGN: Retrospective, Cohort Study. SETTING: Controlled Laboratory. PARTICIPANTS: Patients following Anterior Cruciate Ligament Reconstruction (ACLR) were recruited through an ongoing RTA assessment program. Patients were stratified into two testing groups = "Single RTA test": only assessment between 6 and 9 months post-ACLR and "Repeat RTA test": prior assessment performed >2-months before their RTA assessment. Patients were matched based on time post-surgery, age, activity level, and graft type. MAIN OUTCOME MEASURE: Self-reported knee function and isokinetic knee flexor and extensor strength/symmetry were compared between groups. RESULTS: 392 patients were identified. Once matched, 138 patients (21.1 ± 7.0 years, 7.3 ±0 .9 mo post-ACLR) were analyzed. Repeat RTA test patients demonstrated higher measures of self-reported knee function (P = .04) and greater knee flexion strength (P = .006) and symmetry (P = .05). CONCLUSION: Patients with interim functional assessments reported greater self-reported knee function and higher hamstring strength at the time of RTA compared to patients that completed their only assessment within this time point. Early functional assessments may identify individualized deficits that can be addressed while patients are under supervision of rehabilitation specialists.

Disagreement in Pass Rates Between Strength and Performance Tests in Patients Recovering From Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Performance on strength and functional tests is often used to guide postoperative rehabilitation progress and return to activity decisions after anterior cruciate ligament reconstruction (ACLR). Clinicians may have difficulty in determining which criteria to follow if there is disagreement in performance outcomes among the tests. PURPOSE/HYPOTHESIS: The purpose of this study was to compare pass rates between strength tests and single-leg hop (SLHOP) tests among men and women and between patients with lower and higher preinjury activity levels recovering from ACLR. We hypothesized that pass rates would be nonuniformly distributed among test types, sex, and activity level and that more participants would pass hop tests than strength tests. DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 299 participants (146 men; 153 women)-at a mean of 6.8 ± 1.4 months after primary, unilateral, and uncomplicated ACLR (mean age, 23 ± 9.7 years; mean height, 172 ± 10.5 cm; mean mass, 75.8 ± 18.4 kg)-completed testing. Quadri.tif strength was evaluated using peak torque during isokinetic knee extension at 90 deg/s and 180 deg/s. Jump distance during the SLHOP and triple hop tests was measured (in cm). Strength and hop test measures were evaluated based on the limb symmetry index ((LSI) = (ACLR / contralateral side) × 100). We operationally defined "pass" as >90% on the LSI. RESULTS: Pass rates were nonuniformly distributed between isokinetic knee extension at 90 deg/s and the SLHOP test (χ2 = 18.64; P < .001). Disagreements between isokinetic testing at 90 deg/s and the SLHOP test occurred in 36.5% (109/299) of the participants. Among those who failed strength testing and passed hop testing, a greater portion reported higher activity levels before their injury (χ2 = 6.90; P = .01); however, there was no difference in pass rates between men and women. Similar patterns of disagreement were observed between all strength test and hop test outcomes. CONCLUSION: ACLR patients with higher activity levels may be more likely to pass hop testing despite failing quadri.tif strength testing. This may be an indicator of movement compensations to achieve jump symmetry in the presence of quadri.tif weakness.

Effects of rehabilitation on joint-coupling in patients with chronic ankle instability.

Chronic ankle instability (CAI) is associated with kinematic changes in the lower extremity. Alterations in joint-coupling have been identified during gait in patients with CAI. Rehabilitation remains the gold-standard for clinical treatment of CAI but little is known on the effects of rehabilitation on joint-coupling variability. Wearable destabilisation devices have shown an increase in muscle activity during functional tasks and may be useful in rehabilitation. The purpose of this study is to analyse the joint-coupling variability during gait prior to and following a rehabilitation programme performed with and without destabilisation devices. Twenty-six individuals with CAI were randomly assigned to receive 4 weeks of comprehensive rehabilitation with or without destabilisation devices. A 3D motion capture system was used to collect kinematics during walking. A vector-coding analysis was used to assess the joint-coupling variability of knee and hip motion to ankle motion. The destabilisation device group had decreases in joint-coupling variability during periods of walking gait. This decrease in joint-coupling variability may represent a change in sensorimotor organisation following rehabilitation. This decrease is indicative of an adaptation to the rehabilitation using destabilisation devices and may indicate an improvement in sensorimotor function.

ISB clinical biomechanics award winner 2019: Knee extensor fatigue resistance in individuals following anterior cruciate ligament reconstruction.

BACKGROUND: Individuals following anterior cruciate ligament reconstruction demonstrate quadriceps weakness throughout the post-operative recovery and at the time of returning to sport. This is often accompanied with patterns of quadriceps fatigue resistance. As such, fatigue may be an identifier of individuals with delayed recovery. The purpose was to assess quadriceps fatigue in anterior cruciate ligament reconstructed patients at the time of return to sport in comparison to healthy controls. METHODS: A total of 215 individuals, 120 following anterior cruciate ligament reconstruction (21.0 (2.9) years, 63 Female, 5.96 (0.48) months post-surgery) and 95 healthy controls (21.5 (8.4) years, 49 Female), participated in this study. All participants completed a 30-s knee extensor maximum voluntary isometric contraction. Knee extensor strength, limb symmetry index, and fatigue (%) were compared between groups. Between-limb fatigue comparisons were made through the Fatigue Index Limb Difference = [(Involved Limb Fatigue Index) - (Uninvolved Limb Fatigue Index)]. FINDINGS: Individuals following anterior cruciate ligament reconstruction (18.7 (10.9)%, -5.6 (11.2)) demonstrated lower values of unilateral fatigue and Fatigue Index Limb Difference compared to healthy participants (22.5 (8.2)%, P = .002; 2.2 (7.9), P < .001). For anterior cruciate ligament reconstructed patients, there was a weak, negative, significant relationship between the involved limb strength and fatigue (r = -0.184, P = .048). There was no relationship between limb symmetry and Fatigue Index Limb Difference (r = 0.137, P = .142). For Healthy individuals, there was a positive, moderate relationship between limb symmetry and Fatigue Index Limb Difference (r = 0.400, P < .001). INTERPRETATION: Individuals following anterior cruciate ligament reconstruction demonstrate fatigue resistance compared to healthy active controls and greater resistance to fatigue in their involved limb compared to their contralateral limb.

Visuomotor therapy modulates corticospinal excitability in patients following anterior cruciate ligament reconstruction: A randomized crossover trial.

BACKGROUND: Corticospinal adaptations have been observed following anterior cruciate ligament reconstruction around the time of returning to activity. These measures have been related to quadriceps strength deficits. Visuomotor therapy, combining motor control tasks with visual biofeedback, has been shown to increase corticospinal excitability. The purpose of this study was to assess the immediate changes of corticospinal excitability following a single session of visuomotor therapy in patients following anterior cruciate ligament reconstruction. METHODS: This was a single blinded, sham-controlled crossover study. Ten patients following ACLR (8 Female, 26.1(6.2) years) completed assessments of quadriceps strength at approximately 4- and 6-months following anterior cruciate ligament reconstruction. At 6-months, quadriceps motor evoked potentials were assessed at 80%, 90%, 100%, 110%, 120%, 130%, 140%, and 150% of the patient's active motor threshold. Patients were randomized to receive a single session of visuomotor therapy(active) or passive motion(sham). Quadriceps motor evoked potentials were reassessed for treatment effect. Following a one-week washout period, all patients received the crossover intervention. FINDINGS: Moderate to large increases in motor response following visuomotor therapy 90%(P = .008, r = 0.60), 110%(P = .038, r = 0.46), 120%(P = .021, r = 0.52), 130%(P = .021, r = 0.52), 140%(P = .008, r = 0.60) and 150%(P = .021, r = 0.52) of the active motor threshold were found. Moderate increases in motor response was observed following the passive motion at 80% of the active motor threshold(P = .028, r = 0.49). INTERPRETATION: A single session of visuomotor therapy was found to increase quadriceps corticospinal motor response greater than the response to sham therapy. Visuomotor therapy is a potential supplement to quadriceps rehabilitation programs when upregulation of corticospinal excitability is indicated.

Landing Stiffness Between Individuals With and Without a History of Low Back Pain.

CONTEXT: Reduced spinal stabilization, delayed onset of muscle activation, and increased knee joint stiffness have been reported in individuals with a history of low back pain (LBP). Biomechanical adaptations resulting from LBP may increase the risk for future injury due to suboptimal loading of the lower-extremity or lumbar spine. Assessing landing mechanics in these individuals could help identify which structures might be susceptible to future injury. OBJECTIVE: To compare vertical and joint stiffness of the lower-extremity and lumbar spine between individuals with and without a previous history of LBP. DESIGN: Cross-sectional study. SETTING: Research laboratory. PARTICIPANTS: There were 45 participants (24 without a previous history of LBP-age 23 [8] y, height 169.0 [8.5] cm, mass 69.8 [13.8] kg; 21 with a previous history of LBP-age 25[9] y, height 170.0 [8.0] cm, mass 70.2 [11.8] kg). INTERVENTIONS: Single-limb landing trials on the dominant and nondominant limb from a 30-cm box. MAIN OUTCOME MEASURES: Vertical stiffness and joint stiffness of the ankle, knee, hip, and lumbar spine. RESULTS: Individuals with a previous history of LBP had lower vertical stiffness (P = .04), but not joint stiffness measures compared with those without a previous history of LBP (P > .05). Overall females had lower vertical (P = .01), ankle (P = .02), and hip stiffness (P = .04) compared with males among all participants. Males with a previous history of LBP had lower vertical stiffness compared with males without a previous history LBP (P = .01). Among all individuals without a previous history of LBP, females had lower vertical (P < .01) and ankle stiffness measures (P = .04) compared with males. CONCLUSIONS: Landing stiffness may differ among males and females and a previous history of LBP. Comparisons between individuals with and without previous LBP should be considered when assessing landing strategies, and future research should focus on how LBP impacts landing mechanics.

How Much Time Is Needed Between Serial "Return to Play" Assessments to Achieve Clinically Important Strength Gains in Patients Recovering From Anterior Cruciate Ligament Reconstruction?

BACKGROUND: Pass rates for return-to-play evaluations are alarmingly low for patients after anterior cruciate ligament reconstruction (ACLR). Since timing of return to play is a complicated decision, it is important that patients be given optimal time to realize meaningful improvements in strength that warrant additional testing. PURPOSE: To (1) compare outcomes among patients assessed at different time points after ACLR, (2) determine strength gains indicative of improvements in subjective function, and (3) determine the amount of time necessary to achieve meaningful strength gains. STUDY DESIGN: Cross-sectional/case-control study; Level of evidence, 3. METHODS: A total of 293 patients participated in the study after ACLR (mean ± SD, 23.2 ± 10.1 years old; n = 142 female participants; 6.4 ± 0.9 months after ACLR). Participants were stratified on the month of their evaluation after ACLR: 5 to 6 months (n = 122), 6 to 7 months (n = 102), 7 to 8 months (n = 43), and 8 to 9 months (n = 26). The International Knee Documentation Committee (IKDC) subjective form and knee extensor and flexor torque and symmetry, as assessed through an isokinetic dynamometer, were compared among groups. Forty patients (20 female participants, 20.4 ± 7.1 years old) were referred for subsequent testing (2.14 ± 0.78 months after initial visit). Subjective improvement between visits was defined as a ≥9-point change of the IKDC score. Thresholds of knee extensor torque and symmetry indicative of subjective improvement and the time between assessments needed to achieve these strength improvements were determined. RESULTS: Patients between 5 and 6 months (IKDC, 79.7; interquartile range [IQR], 70.1-88.5) had lower subjective function compared to patients between 6 and 7 months (IKDC, 83.9; IQR, 74.5-92.0; P = .019) and 8 and 9 months after ACLR (IKDC, 89.1; IQR 75.8-92.3; P = .026). Patients between 5 and 6 months (1.41 N·m/kg; IQR, 1.16-1.73 N·m/kg]) had lower knee extensor torque compared to patients 6 and 7 months (1.59 N·m/kg; IQR, 1.23-1.95 N·m/kg; P = .013) and 7 and 8 months after ACLR (1.62 N·m/kg; IQR, 1.30-1.86 N·m/kg; P = .046). Patients between 5 and 6 months (66.4%; IQR, 54.2-78.6) had lower symmetry compared to patients between 6 and 7 months (71.8%; IQR,61.1-82.9; P = .019) and 8 and 9 months afterACLR (75.2%; IQR, 66.6-87.7; P = .014). Of the 40 patients that completed follow-up assessments, an increase in knee extensor torque of 0.22 N·m/kg and symmetry of 5.75% discriminated patients that achieved subjective improvement. A period of 1.97 months between assessments discriminated those that achieved the established symmetry threshold. CONCLUSION: Patients demonstrate increasing subjective and quadriceps function when tested at later time points from surgery; however, the observed values are low, suggesting that at 9 months patients are demonstrating deficits that may be improving. Approximately 2 months is needed to observe clinically meaningful improvements.

Prospective, Randomized, Double-Blind Evaluation of the Efficacy of a Single-Dose Hyaluronic Acid for the Treatment of Patellofemoral Chondromalacia.

BACKGROUND: Patellofemoral pain is common in the young and active populations. Nonoperative management is limited and focuses on physical therapy. Hyaluronic acid (HA) is an injectable device that has been used for the treatment of knee osteoarthritis. HYPOTHESIS: A single injection of HA would reduce pain and improve function in patients with patellofemoral pain who had previously failed conservative management. STUDY DESIGN: Randomized controlled trial; Level of evidence, 2. METHODS: A total of 86 patients with patellofemoral pain (65 females, 21 males; mean ± SD age, 27.0 ± 7.7 years; height, 168.6 ± 8.9 cm; weight, 74.6 ± 17.0 kg; body mass index, 26.2 ± 5.2 kg/m2) enrolled in this study after failing conservative management. Patients were randomly allocated to either 6 mL of HA or a sham injection. All patients were prescribed an additional home exercise program, including lower extremity strengthening and flexibility exercises, and were evaluated at 1, 3, and 6 months. Outcome assessments included patellofemoral pain assessment with a visual analog scale during a single-legged squat, KOOS (Knee injury and Osteoarthritis Outcome Score), Kujala score, Tegner activity rating, and normalized isometric knee extension strength. Group assignment was revealed after the 6-month assessment, and crossover treatment was offered to patients in the sham group who were still symptomatic. Linear mixed models were used to compare outcomes between groups and across time. RESULTS: A total of 45 patients were randomized to HA injection and 41 to sham, with 6 patients lost to follow-up (93% follow-up rate). Patients in both groups experienced a significant reduction in visual analog pain ratings and significant improvements in all domains of the KOOS and in Kujala scores at 6 months when compared with baseline measurement (P < .05); however, there was no significant difference between groups. There were no differences observed over time or between groups for normalized knee extension strength or Tegner activity rating (P > .05). CONCLUSION: HA injection had no clinically meaningful effect on pain or functional outcomes in patients diagnosed with patellofemoral pain. Improvements were observed for both groups in patient-reported pain and function, with no change in quadriceps strength or activity rating. REGISTRATION: NCT01771952 (ClinicalTrials.gov identifier).

Effect of Sex and Level of Activity on Lower-Extremity Strength, Functional Performance, and Limb Symmetry.

Context: Strength, functional performance, and limb symmetry are common objective clinical assessments used by clinicians to guide safe return to physical activity following injury. Population-specific unilateral limb outcomes or estimates of limb symmetry of these assessments should be established. Objective: To compare lower-extremity strength, functional performance, and limb symmetry in healthy participants based on sex and level of activity. Design: Descriptive laboratory study. Setting: Laboratory. Participants: A total of 117 healthy participants (72 males and 45 females; mass = 73.67 [13.60] kg, height = 1.76 [0.12] m, and age = 21.44 [2.92] y) without history of injury within 6 months were included. Interventions: Participants completed isokinetic concentric and isometric knee extension and flexion strength tasks at 90°/s, 180°/s, and 90°, respectively, and 4 hop tasks (single, cross-over, triple, and 6-m timed) during 1 session. Groups were separated by sex (male and female) and activity level (athlete and nonathlete). Participants rostered on National Collegiate Athletic Association (NCAA) Division I (DI) teams were considered as athletes, and non-NCAA DI healthy, uninjured participants were considered as nonathletes. Main Outcome Measures: Limb symmetry index (LSI), maximal voluntary isometric contraction (N·m/kg), peak torque (N·m/kg), average power (N·m/s), distance (m), and time hopped (s) were assessed. LSI was calculated by dividing the lower limb outcome by the higher limb outcome of the nondominant or dominant limb. Group differences were assessed through Mann-Whitney U tests and Cohen's d effect sizes for all comparisons. Results: LSI differences did not exist between groups. Mean LSIs for all participants ranged between 83.52% (12.54%) and 96.16% (3.82%). On average, males were stronger (range: d = 0.63-1.54), hopped farther (range: d = 1.52-1.63), and hopped faster (range: d = 1.67-1.68) than females. On average, some strength differences existed between athletes and nonathletes, but athletes hopped farther (range: d = 0.71-0.82) and faster (range: d = 0.87-0.88) than nonathletes. Conclusions: Unilateral limb strength and functional performance outcomes differ between sex and activity level, but not limb symmetry. These differences may be important for a clinician's understanding of normative values of common return-to-play assessment tasks.

Relationships of Muscle Function and Subjective Knee Function in Patients After ACL Reconstruction.

BACKGROUND: After anterior cruciate ligament reconstruction (ACLR), relationships between objective measures of muscle function and patient-reported outcomes may change over time. Examining these measures at different time frames after surgery may help develop individualized approaches to improve post-ALCR analysis. PURPOSE: To examine the associations between subjective knee function and lower-extremity muscle function in individual patients at various time points after ACLR. STUDY DESIGN: Descriptive laboratory study. METHODS: Fifty-one participants who underwent primary, unilateral ACLR (15 males, 36 females; mean age, 22.9 ± 4.5 years; mean height, 172.4 ± 10.1 cm; mean weight, 68.7 ± 13.1 kg) were separated into 3 groups depending on time since surgery (early, <2 years; middle, 2-5 years; late, >5 years). Subjective knee function was quantified using the International Knee Documentation Committee (IKDC) subjective knee form and the Knee injury and Osteoarthritis Outcome Score (KOOS). Isometric knee extension and flexion strength were collected at 90 deg/s. Single-leg hop performance was measured using the single hop, triple hop, cross-over hop, and 6-m timed hop. Coefficient correlations were calculated between subjective knee function and objective measures of muscle function for each group. RESULTS: The early group demonstrated moderate correlations between the KOOS and unilateral measures of flexion peak torque (r = 0.514, P = .035) and flexion power (r = 0.54, P = .027). The middle group demonstrated the strongest correlations between the KOOS and symmetry measures of the single hop (r = 0.69, P = .002) and extension work (r = 0.71, P = .002) as well as unilateral measures of the triple hop (r = 0.52, P = .034) and extension work (r = 0.66, P = .004). The late group demonstrated strong correlations between the 6-m timed hop symmetry and the IKDC (r = 0.716, P = .001) and KOOS (r = 0.71, P = .001). CONCLUSION: Patients with a post-ACLR status of less than 2 years exhibited stronger relationships with unilateral strength measures to subjective function; graft type was found to change these relationships. Patients at 2 to 5 years postsurgery demonstrated relationships with both unilateral and symmetry measures of muscle function to subjective function. Patients who were more than 5 years after ACLR exhibited strong associations between hopping symmetry and subjective function. CLINICAL RELEVANCE: Future clinical guidelines for patients after ACLR may need to consider time since surgery as a potential factor.