Strategies for enhancing proprioception and neuromuscular control of the knee

EMG-Informed Musculoskeletal Modeling to Estimate Realistic Knee Anterior Shear Force During Drop Vertical Jump in Female Athletes

The anterior cruciate ligament is the primary structural restraint to tibial anterior shear force. The anterior force occurring at the knee during landing contributes to anterior cruciate ligament injury risk, but it cannot be directly measured experimentally. The objective of this study was to develop electromyography-informed musculoskeletal simulations of the drop vertical jump motor task and assess the contribution of knee muscle forces to tibial anterior shear force. In this cross-sectional study, musculoskeletal simulations were used to estimate the muscle forces of thirteen female athletes performing a drop vertical jump using an electromyography-informed method. Muscle activation and knee loads that resulted from these simulations were compared to the results obtained with the more common approach of minimization of muscle effort (optimization-based method). Quadriceps-hamstrings and quadriceps-gastrocnemius co-contractions were progressively increased and their contribution to anterior shear force was quantified. The electromyography-informed method produced co-contraction indexes more consistent with electromyography data than the optimization-based method. The muscles that presented the largest contribution to peak anterior shear force were the gastrocnemii, likely from their wrapping around the posterior aspect of the tibia. The quadriceps-hamstring co-contraction provided a protective effect on the ACL and reduced peak anterior shear force by 292 N with a co-contraction index increase of 25% from baseline (31%), whereas a quadriceps-gastrocnemius co-contraction index of 61% increased peak anterior shear force by 797 N compared to baseline (42%). An increase in gastrocnemius contraction, which might be required to protect the ankle from the impact with the ground, produced a large quadriceps-gastrocnemius co-activation, increasing peak anterior shear force. A better understanding of each muscle's contribution to anterior shear force and, consequently, anterior cruciate ligament tension may inform subject-specific injury prevention programs and rehabilitation protocols.

Do neoprene sleeves and prophylactic knee braces affect neuromuscular control and cutting agility?

OBJECTIVES

To evaluate the effects of neoprene sleeves (NSs) and prophylactic knee braces (PKBs) on neuromuscular control and cutting agility.

DESIGN

Markerless motion-capture technology tracked subjects (1) without a brace as a control (2) with NSs and (3) with PKBs during single-leg drop vertical jump (SLDVJ), single-leg squat (SLS), Y-excursion, and cutting movements. Movements were recorded five times per bracing condition in three different sessions.

SETTING

University laboratory.

PARTICIPANTS

Ten healthy, active subjects (5 male, 5 female; age range, 22-26 years).

MAIN OUTCOME MEASURES

Degrees of motion and time to completion.

RESULTS

Use of NSs and PKBs reduced subjects' hip internal rotation in the loading phase of SLDVJ (p = 0.026, 0.02) and SLS (p = 0.005, <0.001), reduced knee flexion in the loading phase of SLDVJ (p = 0.038, <0.001), and reduced knee frontal plane abduction (FPA) with SLS (p = 0.015, 0.024) and Y-excursion (p = 0.002, 0.005) compared to control. Use of PKBs decreased subjects' hip internal rotation in the Y-excursion (p = 0.024) and reduced knee FPA in the SLDVJ loading phase (p = 0.014) compared to control. There was no difference in cutting agility for either group (p = 0.145, 0.347).

CONCLUSION

Both NSs and PKBs positively impacted neuromuscular control without impacting cutting agility.

ACL Repair With Suture Ligament Augmentation Is Associated With a High Failure Rate Among Adolescent Patients

BACKGROUND

The anterior cruciate ligament (ACL) repair technique avoids graft harvest and therefore the risk of donor site morbidity. However, early failure rates after ACL repair with suture ligament augmentation (SLA) remain high.

PURPOSE

To compare surgical failure, functional outcomes, return to sport, and joint laxity between adolescents who underwent ACL repair with SLA and those who underwent ACL reconstruction with quadriceps tendon-patellar bone autograft (QPA).

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Adolescent patients (7-18 years old) underwent ACL repair with SLA or ACL reconstruction with QPA. The authors collected data from those who had postoperative information pertaining to repaired ligament or graft failure, range of motion, complications, and return to sport at a minimum of 6 months after surgery. Participants were contacted after surgery to complete study questionnaires.

RESULTS

The cohort included 22 consecutive patients in the SLA group and 157 in the QPA group. The median duration of follow-up was 2.7 years (interquartile range, 2.0-3.6 years) in the QPA group and 3.2 years (2.2-3.4 years) in the SLA group. After adjustment for sex, age, body mass index, and time from injury to surgery, the hazard of graft failure in the SLA group was 10.66 times (95% CI, 3.41-32.92; P < .0001) that of the QPA group. The cumulative incidence of graft failure in the first 3 years after surgery was 48.8% (95% CI, 28.9%-73.1%) in the SLA group, as opposed to 4.7% (2.1%-10.3%) in the QPA group. There was no difference in return to sport between the groups. Among individuals who did not rerupture their ACL, International Knee Documentation Committee and Lysholm scores were comparable between the groups, as well as range of motion.

CONCLUSION

The risk of failure was significantly increased in the SLA group relative to the QPA group. The high risk of failure for the SLA group in this short-term follow-up should be considered when selecting the treatment for adolescent patients with an ACL injury.

Systematic Selection of Key Logistic Regression Variables for Risk Prediction Analyses: A Five-Factor Maximum Model

GENERAL AND CRITICAL REVIEW FORMAT

The evolution of clinical practice and medical technology has yielded an increasing number of clinical measures and tests to assess a patient's progression and return to sport readiness after injury. The plethora of available tests may be burdensome to clinicians in the absence of evidence that demonstrates the utility of a given measurement.

OBJECTIVE

Thus, there is a critical need to identify a discrete number of metrics to capture during clinical assessment to effectively and concisely guide patient care.

DATA SOURCES

The data sources included Pubmed and PMC Pubmed Central articles on the topic. Therefore, we present a systematic approach to injury risk analyses and how this concept may be used in algorithms for risk analyses for primary anterior cruciate ligament (ACL) injury in healthy athletes and patients after ACL reconstruction.

MAIN RESULTS

In this article, we present the five-factor maximum model, which states that in any predictive model, a maximum of 5 variables will contribute in a meaningful manner to any risk factor analysis.

CONCLUSIONS

We demonstrate how this model already exists for prevention of primary ACL injury, how this model may guide development of the second ACL injury risk analysis, and how the five-factor maximum model may be applied across the injury spectrum for development of the injury risk analysis.

Analysis of Lower Extremity Proprioception for Anterior Cruciate Ligament Injury Prevention: Current Opinion

Lower extremity musculoskeletal injuries-such as ACL injury-are common, and the majority of those injuries occur without external player contact. In order to prevent non-contact musculoskeletal injuries, athletes must rely on accurate sensory information (such as visual, vestibular, and somatosensory) and stabilize joints during athletic tasks. Previously, proprioception tests (the senses of joint position, movement, tension or force) have been examined using static tests. Due to the role of proprioception in achievement of joint stability, it is essential to explore the development of dynamic proprioception tests. In this current opinion, the basic background on proprioception is covered, and the research gaps and future directions are discussed.

Reliability of two functional clinical tests to evaluate trunk and lumbopelvic neuromuscular control and proprioception in a healthy population

OBJECTIVES

The need to accurately assess trunk and lumbopelvic proprioception and neuromuscular control is widely accepted. However, based on current literature, there is a lack of reliable clinical tests to evaluate these aspects in clinical practice. The objective of this study is to investigate intra- and inter-tester reliability of the lateral step down test and the lumbopelvic position-reposition test in a healthy population.

METHODS

Protocol and scoring methods were developed for the lateral step down test and lumbopelvic position-reposition test, used to assess trunk and lumbopelvic neuromuscular control and proprioception respectively. Each test was performed once by thirty participants and video analysis for test scoring was performed. Three items on the lateral step down test were scored to evaluate neuromuscular control and, four items on the lumbopelvic position-reposition test were scored to evaluate proprioception. Aggregate scores for each test were calculated based on the separate item scores. Intraclass correlation coefficients and linear weighted kappa coefficients were determined for intra- and inter-tester reliability.

RESULTS

Based on the aggregate score, excellent intra- and inter-tester reliability (ICC (2,1)=0.73-0.88) was found for both tests. Moderate/almost perfect intra-and inter-tester agreement (K=0.62-0.91) was found for the separate items of the lateral step down test and fair/substantial agreement (K=0.25-0.76) for the items of the lumbopelvic position-reposition test.

CONCLUSION

Current testing protocol and scoring method for the lateral step down test is reliable. Adjustments for the scoring method of the lumbopelvic position-reposition test are warranted to improve reliability.

Should Return to Sport be Delayed Until 2 Years After Anterior Cruciate Ligament Reconstruction? Biological and Functional Considerations

Anterior cruciate ligament (ACL) tears are common knee injuries sustained by athletes during sports participation. A devastating complication of returning to sport following ACL reconstruction (ACLR) is a second ACL injury. Strong evidence now indicates that younger, more active athletes are at particularly high risk for a second ACL injury, and this risk is greatest within the first 2 years following ACLR. Nearly one-third of the younger cohort that resumes sports participation will sustain a second ACL injury within the first 2 years after ACLR. The evidence indicates that the risk of second injury may abate over this time period. The incidence rate of second injuries in the first year after ACLR is significantly greater than the rate in the second year. The lower relative risk in the second year may be related to athletes achieving baseline joint health and function well after the current expected timeline (6-12 months) to be released to unrestricted activity. This highlights a considerable debate in the return to sport decision process as to whether an athlete should wait until 2 years after ACLR to return to unrestricted sports activity. In this review, we present evidence in the literature that athletes achieve baseline joint health and function approximately 2 years after ACLR. We postulate that delay in returning to sports for nearly 2 years will significantly reduce the incidence of second ACL injuries.

The effects of a simulated occupational kneeling exposure on squat mechanics and knee joint load during gait

Occupational kneeling is associated with an increased risk for tibiofemoral knee osteoarthritis. Forces on the knee in the kneeling posture, as well as the greater incidence of meniscus tears among workers, likely contribute to the increased risk. We hypothesise that an additional mechanism may contribute - altered neuromuscular control due to prolonged high knee flexion. Forty participants (20 male, 20 female) completed an evaluation of gait and squatting before, immediately following, and 30 min following a 30 min simulated occupational kneeling exposure. An increase in the peak external knee adduction moment and a delay in vastus medialis activation onset during walking were observed post-kneeling, as well as increased frontal plane knee motion during squatting. This was the first investigation to find changes in high flexion transitions as a result of kneeling. Greater frontal plane knee motion may increase the risk for meniscal tears, and subsequently, knee osteoarthritis. Practitioner Summary: A 30 min simulated occupational kneeling exposure resulted in small but significant gait changes. The greatest effect was on frontal plane knee movement during squatting, which is especially relevant to occupations requiring frequent kneeling/squatting. This increased motion may indicate an increased risk of injury, which supports a link to knee osteoarthritis.

Cognitive Demands Influence Lower Extremity Mechanics During a Drop Vertical Jump Task in Female Athletes

Study Design Cross-sectional study. Background The drop vertical jump task is commonly used to screen for anterior cruciate ligament injury risk; however, its predictive validity is limited. The limited predictive validity of the drop vertical jump task may be due to not imposing the cognitive demands that reflect sports participation. Objectives To investigate the influence of additional cognitive demands on lower extremity mechanics during execution of the drop vertical jump task. Methods Twenty uninjured women (age range, 18-25 years) were required to perform the standard drop vertical jump task, as well as drop vertical jumps that included additional cognitive demands. The additional cognitive demands were related to attending to an overhead goal (ball suspended overhead) and/or temporal constraints on movement selection (decision making). Three-dimensional ground reaction forces and lower extremity mechanics were compared between conditions. Results The inclusion of the overhead goal resulted in higher peak vertical ground reaction forces and lower peak knee flexion angles in comparison to the standard drop vertical jump task. In addition, participants demonstrated greater peak knee abduction angles when trials incorporated temporal constraints on decision making and/or required participants to attend to an overhead goal, in comparison to the standard drop vertical jump task. Conclusion Imposing additional cognitive demands during execution of the drop vertical jump task influenced lower extremity mechanics in a manner that suggested increased loading of the anterior cruciate ligament. Tasks utilized in anterior cruciate ligament injury risk screening may benefit from more closely reflecting the cognitive demands of the sports environment. J Orthop Sports Phys Ther 2018;48(5):381-387. Epub 10 Jan 2018. doi:10.2519/jospt.2018.7739.

A Novel Mass-Spring-Damper Model Analysis to Identify Landing Deficits in Athletes Returning to Sport After Anterior Cruciate Ligament Reconstruction

Schneider, DK, Gokeler, A, Otten, E, Ford, KR, Hewett, TE, Divine, JG, Colosimo, AJ, Heidt, RS, and Myer, GD. A Novel mass-spring-damper model analysis to identify landing deficits in athletes returning to sport after anterior cruciate ligament reconstruction. J Strength Cond Res 31(9): 2590-2598, 2017-A mass-spring-damper (MSD) model may serve as an extension of biomechanical data from 3-dimensional motion analysis and epidemiological data which helps to delineate populations at risk for anterior cruciate ligament (ACL) injuries. The purpose of this study was to evaluate such a model. Thirty-six ACL reconstruction (ACLR) group subjects and 67 controls (CTRL) completed single-leg drop landing and single-leg broad jump tasks. Landing ground reaction force data were collected and analyzed with an MSD model. Medians, interquartile ranges, and limb symmetry indices (LSIs) were calculated and comparisons were made within and between groups. During a single-leg drop landing, the ACLR group had a lower spring LSI than the CTRL group (p = 0.015) and landed with decreased stiffness in the involved limb relative to the uninvolved limb (p = 0.021). The ACLR group also had an increased damping LSI relative to the CTRL group (p = 0.045). The ACLR subjects landed with increased stiffness (p = 0.006) and decreased damping (p = 0.003) in their involved limbs compared to CTRL subjects' nondominant limbs. During a single-leg forward broad jump, the ACLR group had a greater spring LSI value than the CTRL group (p = 0.045). The CTRL group also recorded decreased damping values in their nondominant limbs compared with the involved limbs of the ACLR group (p = 0.046). Athletes who have undergone ACLR display different lower-limb dynamics than healthy controls, according to an MSD model. Quadriceps dominance and leg dominance are components of ACLR athletes' landing strategies and may be identified with an MSD model and addressed during rehabilitation.

The Effects of Maturation on Measures of Asymmetry During Neuromuscular Control Tests in Elite Male Youth Soccer Players

PURPOSE

Asymmetry is a risk factor for male youth soccer players. There is a paucity of data confirming the presence of asymmetry using practically viable screening tasks in players at different stages of maturation.

METHODS

A cross-sectional sample (N = 347) of elite male youth soccer players who were either pre-, circa-, or post-peak height velocity (PHV) completed the following assessments: single-leg Y-Balance anterior reach, single-leg hop for distance, single-leg 75% hop and stick, and single-leg countermovement jumps.

RESULTS

Single-leg countermovement jumps landing force asymmetry was higher in both circa- and post-PHV groups (P < .001; d = 0.41-0.43). Single-leg 75% hop and stick landing force asymmetries were also highest in circa-PHV players, but between-group comparisons were not statistically significant and effect sizes were small. Single-leg hop for distance and single-leg Y-Balance anterior reach asymmetries reduced with maturation; however, no group differences were significant, with small to trivial effect sizes (d ≤ 0.25).

CONCLUSION

Stage of maturation did not have a profound effect on asymmetry. Between-limb differences in functional performance seem to be established in early childhood; thus, targeted interventions to reduce this injury risk factor should commence in pre-PHV athletes and be maintained throughout childhood and adolescence to ensure asymmetry does not increase.

Brain Activity Changes in Somatosensory and Emotion-Related Areas With Medial Patellofemoral Ligament Deficiency

BACKGROUND

Patellar instability with medial patellofemoral ligament (MPFL) deficiency is a common sports injury among young people. Although nonoperative and surgical treatment can provide stability of the patella, patients often have anxiety related to the knee. We speculate that neural dysfunction may be related to anxiety in these patients; however, the mechanism in the brain that generates this anxiety remains unknown.

QUESTIONS/PURPOSES

(1) How does brain activity in patients with MPFL deficiency change in the areas related to somatic sensation against lateral shift of the patella? (2) How does patella instability, which can lead to continuous fear or apprehension for dislocation, influence brain activity in the areas related to emotion?

METHODS

Nineteen patients with MPFL deficiency underwent surgical reconstruction in our hospital from April 2012 to March 2014. Excluding seven patients with osteochondral lesions, 12 patients (five males and seven females; mean age, 20 years) with MPFL deficiency were sequentially included in this study. Eleven control subjects (four males and seven females; mean age, 23 years) were recruited from medical students who had no history of knee injury. Diagnosis of the MPFL deficiency was made with MR images, which confirmed the rupture, and by proving the instability with a custom-made biomechanical device. Brain activity during passive lateral stress to the patella was assessed by functional MRI. Functional and anatomic images were analyzed using statistical parametric mapping. Differences in functional MRI outcome measures from the detected activated brain regions between the patients with MPFL deficiency and controls were assessed using t tests.

RESULTS

Intergroup analysis showed less activity in several sensorimotor cortical areas, including the contralateral primary somatosensory areas (% signal change for MPFL group 0.49% versus 1.1% for the control group; p < 0.001), thalamus (0.2% versus 0.41% for the MPFL versus control, respectively; p < 0.001), ipsilateral thalamus (0.02% versus 0.27% for the MPFL versus control, respectively; p < 0.001), and ipsilateral cerebellum (0.82% versus 1.25% for the MPFL versus control, respectively; p < 0.001) in the MPFL deficiency group than in the control group. In contrast, the MPFL deficiency group showed more activity in several areas, including the contralateral primary motor area (1.06% versus 0.6% for the MPFL versus control, respectively; p < 0.001), supplementary motor area (0.89% versus 0.52% for the MPFL versus control, respectively; p < 0.001), prefrontal cortex (1.09% versus 1.09% for the MPFL versus control, respectively; p < 0.001), inferior parietal lobule (0.89% versus 0.62% for the MPFL versus control, respectively; p < 0.001), anterior cingulate cortex (0.84% versus 0.08% for the MPFL versus control, respectively; p < 0.001), visual cortex (0.86% versus 0.14% for the MPFL versus control, respectively; p < 0.001), vermis (1.18% versus 0.37% for the MPFL versus control, respectively; p < 0.001), and ipsilateral prefrontal cortex (1.1% versus 0.75% for the MPFL versus control, respectively; p < 0.001) than did the control group.

CONCLUSIONS

Less activity in the contralateral somatosensory cortical areas suggested that MPFL deficiency may lead to diminished somatic sensation against lateral shift of the patella. In contrast, increased activity in the anterior cingulate cortex, prefrontal cortex, and inferior parietal lobule may indicate anxiety or fear resulting from patellar instability, which is recognized as an aversion similar to that toward chronic pain.

CLINICAL RELEVANCE

This study suggests that specific brain-area activity is increased in patients with MPFL deficiency relative to that in controls. Further longitudinal research to assess brain activity and proprioception between patients pre- and postreconstructive knee surgery may reveal more regarding how patella instability is related to brain function. We hope that based on such research, a neural approach to improve patella-instability-related brain function can be developed.

Injury prevention in male youth soccer: Current practices and perceptions of practitioners working at elite English academies

Forty-one practitioners inclusive of physiotherapists, sports scientists and strength and conditioning coaches from the academies of elite soccer clubs in the United Kingdom completed an on-line questionnaire which examined their: (1) background information; (2) perceptions of injury occurrence and risk factors; (3) screening and return to play; and (4) approach to designing and delivering injury prevention programmes with a response rate of 55% (41/75). Contact injuries were the most common mechanism reported and players between 13-16 years of age were perceived to be at the greatest risk. Pertinent risk factors included: reduced lower limb and eccentric hamstring strength, proprioception, muscle imbalances, and under developed foundational movement skills. Joint range of motion, jump tests, the functional movement screen, overhead and single leg squats were the most utilised screening methods. Training modalities rated in order of importance included: resistance training, flexibility development, agility, plyometrics and balance training. Training frequency was most commonly once or twice per week, during warm-ups, independent sessions or a combination of both. Injury prevention strategies in this cohort appear to be logical; however, the classification of injury occurrence and application of screening tools to identify "at risk" players do not align with existing research. The frequency and type of training used may also be insufficient to elicit an appropriate stimulus to address pertinent risk factors based on current recommendations.

Non-operative Care of the Patient with an ACL-Deficient Knee

PURPOSE OF REVIEW

The purpose of this review is to provide an update to the most objective, evidence-based path through a non-operative course of rehabilitation after anterior cruciate ligament injury for those hoping to return to pivoting and cutting sports.

RECENT FINDINGS

Anterior cruciate ligament (ACL) injuries are prevalent in pivoting and cutting athletes with many of these patients electing to pursue surgical reconstruction in hopes of returning to prior levels of function. Despite many athletes pursing ACL reconstruction, some may elect to pursue a non-operative course of care. Success with this treatment plan should be defined as the ability to return to sport without subsequent giving way episodes. Identification of those most likely to successfully return to sport with a non-operative course begins with completion of an evidence-based screening tool. If the patient has no concomitant injury and successfully passes the screening, they may proceed to a systematic, evidence-based progression through rehabilitation. Finally, the patient must complete a return to sport program and meet appropriate objective criteria, prior to return to sport.

Neuromuscular Risk Factors for Knee and Ankle Ligament Injuries in Male Youth Soccer Players

Injuries reported in male youth soccer players most commonly occur in the lower extremities, and include a high proportion of ligament sprains at the ankle and knee with a lower proportion of overuse injuries. There is currently a paucity of available literature that examines age- and sex-specific injury risk factors for such injuries within youth soccer players. Epidemiological data have reported movements that lead to non-contact ligament injury include running, twisting and turning, over-reaching and landing. Altered neuromuscular control during these actions has been suggested as a key mechanism in females and adult populations; however, data available in male soccer players is sparse. The focus of this article is to review the available literature and elucidate prevalent risk factors pertaining to male youth soccer players which may contribute to their relative risk of injury.

Return to Sport for Skeletally Immature Athletes After ACL Reconstruction: Preventing a Second Injury Using a Quality of Movement Assessment and Quantitative Measures to Address Modifiable Risk Factors

Background:

Reinjury rates after anterior cruciate ligament reconstruction (ACLR) are highest among young athletes, who consequently suffer from low rates of return to play. Historically, quantitative measures have been used to determine readiness to return to sport; however, they do not assess modifiable risk factors related to the quality of movement.

Purpose:

To determine the effectiveness of a criteria-based rehabilitation progression and return-to-sport criteria on efficient return to activity and prevention of second injury in young athletes post-ACLR.

Study Design:

Case series; Level of evidence, 4.

Methods:

Between December 2010 and 2013, 42 skeletally immature athletes (mean chronologic age, 12 years; range, 10-15 years) who underwent ACLR using ipsilateral hamstring tendon autograft were prospectively evaluated. All athletes progressed through a criteria-based rehabilitation progression; were assessed at specific time frames for strength, biomechanical, and neuromuscular risk factors predictive of injury; and were provided targeted interventions. The final return to sport phase consisted of quantitative testing as well as a quality of movement assessment of several functional movements with progressive difficulty and sports-specific loading. Clearance for unrestricted activity was determined by achieving satisfactory results on both qualitative and quantitative assessments with consideration for the demands of each sport.

Results:

The mean time for return to unrestricted competitive activity was 12 months. All but 3 (7%) athletes returned to their primary sport. Thirty-five athletes (83%) returned to unrestricted activity. Of the 6 (14%) who sustained a second injury, 3 (50%) were injured in sports they were not cleared for. All ACL reinjuries occurred in a cutting sport. Half of reinjuries occurred within 1 year of surgery, while the remaining occurred between 1 and 2 years. Eighty-three percent of reinjuries involved highly competitive cutting athletes.

Conclusion:

In our cohort, the combination of qualitative and quantitative data served as a good indicator for reducing risk and determining readiness to return to sport.

Correlation among proprioception, muscle strength, and balance

[Purpose] To study the correlation among proprioception, muscle strength, and balance. [Subjects and Methods] A balance testing system (Biodex Balance System, BBS) and an isokinetic testing system (Biodex System 4, BS4) were used to test related indexes in 24 healthy young females. [Results] With the knee joint at 15 degree flexion, proprioception was significantly correlated with Limits of Stability-Time values, and was highly significantly correlated with Limits of Stability-Overall and Athlete Single Leg Medial/Lateral values. The sense of force was significantly correlated with Limits of Stability-Overall and Athlete Single Leg-Overall values. Quadriceps strength was significantly associated with Limits of Stability-Overall, Athlete Single Leg Medial/Lateral, and Athlete Double Leg-Overall values. The ratio of Quadriceps to Hamstring strength was significantly correlated with Athlete Single Leg Medial/Lateral, and Athlete Single Leg-Overall values. With the knee joint at 45°, proprioception was highly significantly correlated with dynamic balance, and was significantly correlated with double foot support under static balance; force sense had a high correlation with Limits of Stability-Overall, but no correlation with other indexes. Quadriceps strength had a significant correlation with dynamic and static balance; the ratio of Quadriceps/Hamstring had a highly significant correlation with Limits of Stability-Overall, Athlete Single Leg-Anterior/Posterior and Athlete Single Leg-Overall. [Conclusion] At different knee angles, the correlation differs among proprioception, force sense, quadriceps strength, the Quadriceps/Hamstring ratio, and balance.

Mechanisms, prediction, and prevention of ACL injuries: Cut risk with three sharpened and validated tools

Economic and societal pressures influence modern medical practice to develop and implement prevention strategies. Anterior cruciate ligament (ACL) injury devastates the knee joint leading to short term disability and long term sequelae. Due to the high risk of long term osteoarthritis in all treatment populations following ACL injury, prevention is the only effective intervention for this life-altering disruption in knee health. The "Sequence of Prevention" Model provides a framework to monitor progress towards the ultimate goal of preventing ACL injuries. Utilizing this model, our multidisciplinary collaborative research team has spent the last decade working to delineate injury mechanisms, identify injury risk factors, predict which athletes are at-risk for injury, and develop ACL injury prevention programs. Within this model of injury prevention, modifiable factors (biomechanical and neuromuscular) related to injury mechanisms likely provide the best opportunity for intervention strategies aimed to decrease the risk of ACL injury, particularly in female athletes. Knowledge advancements have led to the development of potential solutions that allow athletes to compete with lowered risk of ACL injury. Design and integration of personalized clinical assessment tools and targeted prevention strategies for athletes at high risk for ACL injury may transform current prevention practices and ultimately significantly reduce ACL injury incidence. This 2016 OREF Clinical Research Award focuses on the authors' work and contributions to the field. The author's acknowledge the many research groups who have contributed to the current state of knowledge in the fields of ACL injury mechanisms, injury risk screening and injury prevention strategies. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1843-1855, 2016.

Evaluation of functional rehabilitation physiotherapy protocol in the postoperative patients with anterior cruciate ligament reconstruction through clinical prognosis: an observational prospective study

Background

The aim of the study was to evaluate the evolution of patients subject to physical treatment based on guidelines of functional rehabilitation after surgery anterior cruciate ligament reconstruction.

Methods

This is a prospective study of 177 patients with anterior cruciate ligament injury, who underwent surgery and physical therapy guideline conducted in an orthopedic clinic in São Paulo, southeastern Brazil. The clinical evolution of patients was made according to Lysholm and IKDC questionnaire on the 1st day after surgery with 30, 90 and 180 days of treatment.

Results

There was statistically significant increase in the gross values of Lysholm and IKDC questionnaires during the treatment (p < 0.001), which indicates progressive gain of function. According to the scores obtained from the IKDC, it can be observed that in stage 1 the average progress was 53.5 %, falling to 50 % in stage 2, and 26.1 % in stage 3. As to Lysholm score, it started with 87.7 %, falling to 62.6 % in the second stage and 7 % in the third stage, both statistically significant (p < 0.001). The rehabilitation-oriented functional objectives priority is to quickly get the exercises to gain breadth, strength and proprioception, optimizing and improving the integration of the athlete back to sport.

Conclusion

Synthesizing the gradual gain of function and according to clinical outcomes assessed by IKDC and Lysholm, the functional guideline presented may be considered an alternative for rehabilitation of patients in postoperative anterior cruciate ligament.

Knee Muscular Control During Jump Landing in Multidirections

BACKGROUND

Jump landing is a complex movement in sports. While competing and practicing, athletes frequently perform multi-planar jump landing. Anticipatory muscle activity could influence the amount of knee flexion and prepare the knee for dynamic weight bearing such as landing tasks.

OBJECTIVES

The aim of the present study was to examine knee muscle function and knee flexion excursion as athletes naturally performed multi-direction jump landing.

MATERIALS AND METHODS

Eighteen male athletes performed the jump-landing test in four directions: forward (0°), 30° diagonal, 60° diagonal, and lateral (90°). Muscles tested were vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF), semitendinosus (ST), and biceps femoris (BF). A Vicon(TM) 612 workstation collected the kinematic data. An electromyography was synchronized with the Vicon(TM) Motion system to quantify dynamic muscle function. Repeated measure ANOVA was used to analyze the data.

RESULTS

Jump-landing direction significantly influenced (P < 0.05) muscle activities of VL, RF, and ST and knee flexion excursion. Jumpers landed with a trend of decreasing knee flexion excursion and ST muscle activity 100 ms before foot contact progressively from forward to lateral directions of jump landing.

CONCLUSIONS

A higher risk of knee injury might occur during lateral jump landing than forward and diagonal directions. Athletes should have more practice in jump landing in lateral direction to avoid injury. Landing technique with high knee flexion in multi-directions should be taught to jumpers for knee injury prevention.

Evaluation of Knee Proprioception and Factors Related to Parkinson's Disease

Background. Changes in proprioception may contribute to postural instability in individuals with neurological disorders. Objectives. Evaluate proprioception in the lower limbs of patients with Parkinson's disease (PD) and the association between proprioception and cognitive ability, motor symptoms, postural instability, and disease severity. Methods. This is a cross-sectional, controlled study that evaluated proprioception in PD patients and healthy age- and sex-matched individuals. Kinetic postural proprioception of the knee was evaluated using an isokinetic dynamometer (Biodex® Multi-Joint System 4 Pro). Participants were evaluated using the Montreal Cognitive Assessment (MoCA), the Hoehn and Yahr rating scale and postural instability (pull test and stabilometric analysis), and motor function (UPDRS-III) tests. Results. A total of 40 individuals were enrolled in the study: 20 PD patients and 20 healthy controls (CG). The PD patients had higher angular errors on the proprioceptive ratings than the CG participants (p = 0.002). Oscillations of the center of pressure (p = 0.002) were higher in individuals with PD than in the controls. Proprioceptive errors in the PD patients were associated with the presence of tremors as the dominant symptom and more impaired motor performance. Conclusion. These findings show that individuals with PD have proprioceptive deficits, which are related to decreased cognitive ability and impaired motor symptoms.

Effects of muscle strength asymmetry between left and right on isokinetic strength of the knee and ankle joints depending on athletic performance level

[Purpose] The aim of this study was to collect basic data on the effect of asymmetry on the muscle strength of the left and right knee and ankle joints of soccer players at varying athletic performance levels, to guide the development of improved exercise programs. [Subjects and Methods] Forty-nine soccer players at three athletic performance levels participated: 15 professional, 16 amateur, and 18 college. Knee extensor and flexor strength were measured at 60°/sec and 180°/sec, and ankle plantar flexor and dorsiflexor strength were measured at 30°/sec and at 120°/sec. Variables were analyzed by one-way ANOVA. [Results] College soccer players showed greater muscle strength at 60°/sec and 180°/sec in the knee extension muscles of both the right and the left sides, lower muscle strength at 30°/sec and 120°/sec in the dorsiflexor of the right ankle, and similar levels of asymmetry between left and right. The maximum muscle strength on the same side significantly differed in the right ankle joint, with asymmetry between left and right at 30°/sec and 120°/sec. [Conclusion] These findings suggest that muscle strength asymmetry in the ankle joint may lead to counterbalancing muscle strengthening of the knee joint to maintain the center of body mass.

EFEITO DO TREINO NEUROMUSCULAR NA ROTAÇÃO DO JOELHO DURANTE A ATERRISSAGEM EM MULHERES

Introdução: O grande índice de lesões do ligamento cruzado anterior sem envolver contato em mulheres é motivo de curiosidade entre os cientistas, pois avaliações de aterrissagem podem sugerir a predisposição ao risco dessa lesão. Neste sentido, vários protocolos de treinamento foram utilizados como intervenção e obtiveram resultados diversificados na alteração desse fator de risco. Objetivo: O objetivo deste projeto foi avaliar as possíveis alterações de rotação do joelho na aterrissagem unipodal após a intervenção de um programa de treinamento neuromuscular. Métodos: Participaram do estudo 18 mulheres com idade entre 18 e 51 anos, que foram distribuídas em dois grupos: grupo de treinamento neuromuscular de oito semanas (GTN) (n = 11) e grupo controle (GC) (n = 7). Além disso, não apresentavam lesão musculoesquelética ou dores nos membros inferiores. Cada participante realizou cinco aterrissagens unipodais válidas de uma plataforma de 40 cm de altura. O processo de captura de movimento foi realizado com 12 câmeras infravermelho do sistema OptiTrack(tm) para obter as coordenadas tridimensionais de marcadores fixados nos pontos anatômicos de interesse. Os sistemas de coordenadas locais da coxa e da perna foram definidos por meio dos respectivos marcadores fixados nos pontos anatômicos. Dessa forma, foram calculados os ângulos de rotação do joelho nos planos sagital, frontal e transverso através das sequências dos ângulos de Euler e as velocidades angulares através das formulações dos quatérnions. Resultados: Os resultados mostraram que houve um aumento na velocidade de rotação do joelho após o treinamento neuromuscular. Conclusão: Conclui-se que o treinamento neuromuscular resultou em maior velocidade de rotação no joelho nos 40 milissegundos que sucedem a aterrissagem unipodal.

Motion Analysis and the Anterior Cruciate Ligament: Classification of Injury Risk

Anterior cruciate ligament (ACL) injuries are common, catastrophic events that incur large expense and lead to degradation of the knee. As such, various motion capture techniques have been applied to identify athletes who are at increased risk for suffering ACL injuries. The objective of this clinical commentary was to synthesize information related to how motion capture analyses contribute to the identification of risk factors that may predict relative injury risk within a population. Individuals employ both active and passive mechanisms to constrain knee joint articulation during motion. There is strong evidence to indicate that athletes who consistently classify as high-risk loaders during landing suffer from combined joint stability deficits in both the active and passive knee restraints. Implementation of prophylactic neuromuscular interventions and biofeedback can effectively compensate for some of the deficiencies that result from poor control of the active knee stabilizers and reduce the incidence of ACL injuries.

Effect of Vertical, Horizontal, and Combined Plyometric Training on Explosive, Balance, and Endurance Performance of Young Soccer Players

The aim of this study was to compare the effects of 6 weeks of vertical, horizontal, or combined vertical and horizontal plyometric training on muscle explosive, endurance, and balance performance. Forty young soccer players aged between 10 and 14 years were randomly divided into control (CG; n = 10), vertical plyometric group (VG; n = 10), horizontal plyometric group (HG; n = 10), and combined vertical and horizontal plyometric group (VHG; n = 10). Players performance in the vertical and horizontal countermovement jump with arms, 5 multiple bounds test (MB5), 20-cm drop jump reactive strength index (RSI20), maximal kicking velocity (MKV), sprint, change of direction speed (CODS), Yo-Yo intermittent recovery level 1 test (Yo-Yo IR1), and balance was measured. No significant or meaningful changes in the CG, apart from small change in the Yo-Yo IR1, were observed while all training programs resulted in meaningful changes in explosive, endurance, and balance performance. However, only VHG showed a statistically significant (p ≤ 0.05) increase in all performance test and most meaningful training effect difference with the CG across tests. Although no significant differences in performance changes were observed between experimental groups, the VHG program was more effective compared with VG (i.e., jumps, MKV, sprint, CODS, and balance performance) and HG (i.e., sprint, CODS, and balance performance) to small effect. The study demonstrated that vertical, horizontal, and combined vertical and horizontal jumps induced meaningful improvement in explosive actions, balance, and intermittent endurance capacity. However, combining vertical and horizontal drills seems more advantageous to induce greater performance improvements.

A conceptual framework for a sports knee injury performance profile (SKIPP) and return to activity criteria (RTAC)

Injuries to the knee, including intra-articular fractures, ligamentous ruptures, and meniscal and articular cartilage lesions, are commonplace within sports. Despite advancements in surgical techniques and enhanced rehabilitation, athletes returning to cutting, pivoting, and jumping sports after a knee injury are at greater risk of sustaining a second injury. The clinical utility of objective criteria presents a decision-making challenge to ensure athletes are fully rehabilitated and safe to return to sport. A system centered on specific indicators that can be used to develop a comprehensive profile to monitor rehabilitation progression and to establish return to activity criteria is recommended to clear athletes to begin a progressive and systematic approach to activities and sports. Integration of a sports knee injury performance profile with return to activity criteria can guide clinicians in facilitating an athlete's safe return to sport, prevention of subsequent injury, and life-long knee joint health.

Risk assessment for anterior cruciate ligament injury

INTRODUCTION

Anterior cruciate ligament tears are one of the most frequent soft tissue injuries of the knee. A torn anterior cruciate ligament leaves the knee joint unstable and at risk for further damage to other soft tissues manifested as pain, dislocation, and osteoarthritis. A better understanding of the anatomical details of knee joints suffering anterior cruciate ligament tears is needed to understand and develop prediction models for anterior cruciate ligament injury and/or tear.

MATERIALS AND METHODS

Magnetic resonance images of 32 patients with anterior cruciate ligament tears and 40 patients with non-tears were evaluated from a physician group practice. Digital measurements of femoral condyle length, femoral notch width, anterior cruciate ligament width in the frontal and sagittal plane, and the anterior cruciate ligament length in the sagittal plane were taken in both groups to identify trends. Monte Carlo simulations were performed (n = 2000) to evaluate the relationship between notch width index and sagittal width and to establish functional relationships among the anatomical parameters for potential injury risk. Sensitivity analysis performed shows the risk of anterior cruciate ligament injury a function of force and notch width index.

RESULTS

Females have a significantly shorter anterior cruciate ligament when compared to that of males. The notch width index was also significantly different between torn and non-torn individuals. The NWI was not significantly different between genders (p value = 0.40).

CONCLUSIONS

Anterior cruciate ligament injury has been shown to be caused by the forces which act on the ligament. These forces can result from hyperextension of the tibia or the internal rotation of tibia. The anatomical parameters of the knee joint (i.e., notch width index, anterior cruciate ligament width and length) have no role in the cause of an injury.

Lower extremity muscle activation onset times during the transition from double-leg stance to single-leg stance in anterior cruciate ligament injured subjects

The goal of this study was to evaluate muscle activation onset times (MAOT) of both legs during a transition task from double-leg stance (DLS) to single-leg stance (SLS) in anterior cruciate ligament injured (ACLI) (n=15) and non-injured control subjects (n=15) with eyes open and eyes closed. Significantly delayed MAOT were found in the ACLI group compared to the control group for vastus lateralis, vastus medialis obliquus, hamstrings medial, hamstrings lateral, tibialis anterior, peroneus longus and gastrocnemius in both vision conditions, for gluteus maximus and gluteus medius with eyes open and for tensor fascia latae with eyes closed. Within the ACLI group, delayed MAOT of tibialis anterior with eyes open and gastrocnemius with eyes closed were found in the injured leg compared to the non-injured leg. All other muscles were not significantly different between legs. In conclusion, the ACLI group showed delayed MAOT not only around the knee, but also at the hip and ankle muscles compared to the non-injured control group. No differences between both legs of the ACLI group were found, except for tibialis anterior and gastrocnemius. These findings indirectly support including central nervous system re-education training to target the underlying mechanisms of these altered MAOT after ACL injury.

Proprioception rehabilitation training system for stroke patients using virtual reality technology

We investigated a virtual reality (VR) proprioceptive rehabilitation system that could manipulate the visual feedback of upper-limb during training and could do training by relying on proprioception feedback only. Virtual environments were designed in order to switch visual feedback on/off during upper-limb training. Two types of VR training tasks were designed for evaluating the effect of the proprioception focused training compared to the training with visual feedback. In order to evaluate the developed proprioception feedback virtual environment system, we recruited ten stroke patients (age: 54.7± 7.83years, on set: 3.29± 3.83 years). All patients performed three times PFVE task in order to check the improvement of proprioception function just before training session, after one week training, and after all training. In a comparison between FMS score and PFVE, the FMS score had a significant relationship with the error distance(r = -.662, n=10, p = .037) and total movement distance(r = -.726, n=10, p = .018) in PFVE. Comparing the training effect between in virtual environment with visual feedback and with proprioception, the click count, error distance and total error distance was more reduced in PFVE than VFVE. (Click count: p = 0.005, error distance: p = 0.001, total error distance: p = 0.007). It suggested that the proprioception feedback rather than visual feedback could be effective means to enhancing motor control during rehabilitation training. The developed VR system for rehabilitation has been verified in that stroke patients improved motor control after VR proprioception feedback training.

The preparatory set: a novel approach to understanding stress, trauma, and the bodymind therapies

Basic to all motile life is a differential approach/avoid response to perceived features of environment. The stages of response are initial reflexive noticing and orienting to the stimulus, preparation, and execution of response. Preparation involves a coordination of many aspects of the organism: muscle tone, posture, breathing, autonomic functions, motivational/emotional state, attentional orientation, and expectations. The organism organizes itself in relation to the challenge. We propose to call this the "preparatory set" (PS). We suggest that the concept of the PS can offer a more nuanced and flexible perspective on the stress response than do current theories. We also hypothesize that the mechanisms of body-mind therapeutic and educational systems (BTES) can be understood through the PS framework. We suggest that the BTES, including meditative movement, meditation, somatic education, and the body-oriented psychotherapies, are approaches that use interventions on the PS to remedy stress and trauma. We discuss how the PS can be adaptive or maladaptive, how BTES interventions may restore adaptive PS, and how these concepts offer a broader and more flexible view of the phenomena of stress and trauma. We offer supportive evidence for our hypotheses, and suggest directions for future research. We believe that the PS framework will point to ways of improving the management of stress and trauma, and that it will suggest directions of research into the mechanisms of action of BTES.

Evaluation of knee joint proprioception and balance of young female volleyball players: a pilot study

[Purpose] The main purpose of our study was the evaluation of the effects of long-term volleyball practice on knee joint proprioception and balance of young female athletes. [Subjects and Methods] An observational case-control study was performed. The study enrolled 19 female volleyball players in the experimental group and 19 sedentary counterparts as controls. A Biodex balance system and dynamometer were used for the evaluations. The paired t-test was used to determine the significance of differences between the performance of athletes and controls. [Results] The knee proprioception analysis showed a significant difference at 60° joint position in active and passive tests. A similar trend, but without significance, was found for the 20° joint position. In the postural stability tests both groups showed similar results with no significant differences between them. [Conclusion] In conclusion, the results indicate a significant influence on joint proprioception is elicited by long-term exposure to a team sport like volleyball. However, the postural stability indexes showed similar trends in both groups, highlighting the analogous ontogenesis of the subjects investigated and the low influence of volleyball practice on postural stability.

Pivoting neuromuscular control and proprioception in females and males

PURPOSE

Noncontact ACL injuries occur most commonly in pivoting sports and are much more frequent in females than in males. However, information on sex differences in proprioceptive acuity under weight-bearing and leg neuromuscular control in pivoting is scarce. The objective of this study was to investigate sex differences in pivoting neuromuscular control during strenuous stepping tasks and proprioceptive acuity under weight-bearing.

METHODS

21 male and 22 female subjects were recruited to evaluate pivoting proprioceptive acuity under weight-bearing, and pivoting neuromuscular control (in terms of leg pivoting instability, stiffness, maximum internal and external pivoting angles, and entropy of time-to-peak EMG in lower limb muscles) during strenuous stepping tasks performed on a novel offaxis elliptical trainer.

RESULTS

Compared to males, females had significantly lower proprioceptive acuity under weight-bearing in both internal and external pivoting directions, higher pivoting instability, larger maximum internal pivoting angle, lower leg pivoting stiffness, and higher entropy of time-to-peak EMG in the gastrocnemius muscles during strenuous stepping tasks with internal and external pivoting perturbations.

CONCLUSIONS

Results of this study may help us better understand factors contributing to ACL injuries in females and males, develop training strategies to improve pivoting neuromuscular control and proprioceptive acuity, and potentially reduce ACL and lower-limb musculoskeletal injuries.

Management of a patient with patellofemoral pain syndrome using neuromuscular training in decreasing medial collapse: a case report

BACKGROUND AND PURPOSE

Medial collapse has been reported to increase patellofemoral stresses. This case describes the examination and treatment of a patient with patellofemoral pain syndrome (PFPS), displaying medial collapse during functional activities. The purpose of this case is twofold: (1) to describe a clinical movement pattern assessment using a 2-dimensional (2D) assessment; and (2) to describe a clinical neuromuscular training program focused on optimal movement patterns.

CASE DESCRIPTION

A 19-year-old female diagnosed with PFPS. Initially, the patient exhibited medial collapse. A treatment approach focused on optimization of functional movement patterns to correct medial collapse through visual input and neuromuscular training was implemented. Interventions focused on correction of faulty movement patterns.

OUTCOMES

After four sessions over 3 weeks, the patient reported cessation of pain and displayed an improved movement pattern without medial collapse during functional activities. Discussion and evidence-based recommendations: The clinical assessment of medial collapse utilized was novel, and a successful outcome with minimal visits was achieved for a patient with PFPS. Further research to establish the reliability and validity of the 2D evaluation method of medial collapse and optimum alignment training for patients with PFPS is necessary.

Principles of postoperative anterior cruciate ligament rehabilitation

It is known that anterior cruciate ligament (ACL) reconstruction needs to be combined with detailed postoperative rehabilitation in order for patients to return to their pre-injury activity levels, and that the rehabilitation process is as important as the reconstruction surgery. Literature studies focus on how early in the postoperative ACL rehabilitation period rehabilitation modalities can be initiated. Despite the sheer number of studies on this topic, postoperative ACL rehabilitation protocols have not been standardized yet. Could common, “ossified” knowledge or modalities really prove themselves in the literature? Could questions such as “is postoperative brace use really necessary?”, “what are the benefits of early restoration of the range of motion (ROM)?”, “to what extent is neuromuscular electrical stimulation (NMES) effective in the protection from muscular atrophy?”, “how early can proprioception training and open chain exercises begin?”, “should strengthening training start in the immediate postoperative period?” be answered for sure? My aim is to review postoperative brace use, early ROM restoration, NMES, proprioception, open/closed chain exercises and early strengthening, which are common modalities in the very comprehensive theme of postoperative ACL rehabilitation, on the basis of several studies (Level of Evidence 1 and 2) and to present the commonly accepted ways they are presently used. Moreover, I have presented the objectives of postoperative ACL rehabilitation in tables and recent miscellaneous studies in the last chapter of the paper.

Nonarthritic hip joint pain

The Orthopaedic Section of the American Physical Therapy Association (APTA) has an ongoing effort to create evidence-based practice guidelines for orthopaedic physical therapy management of patients with musculoskeletal impairments described in the World Health Organization's International Classification of Functioning, Disability, and Health (ICF). The purpose of these clinical practice guidelines is to describe the peer-reviewed literature and make recommendations related to nonarthritic hip joint pain.

Effect of a novel movement strategy in decreasing ACL risk factors in female adolescent soccer players: a randomized controlled trial

OBJECTIVE

To determine the effect of a novel movement strategy incorporated within a soccer warm-up on biomechanical risk factors for anterior cruciate ligament injury during 3 sport-specific movement tasks.

DESIGN

Single-blind, randomized controlled clinical trial.

SETTING

Laboratory setting.

PARTICIPANTS

Twenty top-tier female teenage soccer players.

INTERVENTIONS

Subjects were randomized to the Core Position and Control movement strategy (Core-PAC) warm-up or standard warm-up, which took place before their regular soccer practice over a 6-week period. The Core-PAC focuses on getting the centre of mass closer to the plant foot or base of support.

MAIN OUTCOME MEASURES

Peak knee flexion angle and abduction moments during a side-hop (SH), side-cut, and unanticipated side-cut task after the 6 weeks with (intervention group only) and without a reminder to use the Core-PAC strategy.

RESULTS

The Core-PAC group increased peak flexion angles during the SH task [mean difference = 6.2 degrees; 95% confidence interval (CI), 1.9-10.5 degrees; effect size = 1.01; P = 0.034] after the 6-week warm-up program without a reminder. In addition, the Core-PAC group demonstrated increased knee flexion angles for the side-cut (mean difference = 8.5 degrees; 95% CI, 4.8-12.2 degrees; ES = 2.02; P = 0.001) and SH (mean difference = 10.0 degrees; 95% CI, 5.7-14.3 degrees; ES = 1.66; P = 0.001) task after a reminder. No changes in abduction moments were found.

CONCLUSIONS

The results of this study suggest that the Core-PAC may be one method of modifying high-risk soccer-specific movements and can be implemented within a practical, team-based soccer warm-up. The results should be interpreted with caution because of the small sample size.

Clinical rehabilitation guidelines for matrix-induced autologous chondrocyte implantation on the tibiofemoral joint

Autologous chondrocyte implantation (ACI) has become an established technique for the repair of full-thickness chondral defects in the knee. Matrix-induced ACI (MACI) is the third and current generation of this surgical technique, and, while postoperative rehabilitation following MACI aims to restore normal function in each patient as quickly as possible by facilitating a healing response without overloading the repair site, current published guidelines appear conservative, varied, potentially outdated, and often based on earlier ACI surgical techniques. This article reviews the existing evidence-based literature pertaining to cell loading and postoperative rehabilitation following generations of ACI. Based on this information, in combination with the technical benefits provided by third-generation MACI in comparison to its surgical predecessors, we present a rehabilitation protocol for patients undergoing MACI in the tibiofemoral joint that has now been implemented for several years by our institution in patients with MACI, with good clinical outcomes.

Neuromuscular training to target deficits associated with second anterior cruciate ligament injury

SYNOPSIS

Successful return to previous level of activity following anterior cruciate ligament (ACL) reconstruction is not guaranteed, and the prevalence of second ACL injury may be as high as 30%. In particular, younger athletes who return to sports activities within the first several months after ACL reconstruction may be at significantly greater risk of a second ACL rupture compared to older, less active individuals. Significant neuromuscular deficits and functional limitations are commonly identified in athletes following ACL reconstruction, and these abnormal movement and neuromuscular control profiles may be both residual of deficits existing prior to the initial injury and exacerbated by the injury and subsequent ACL reconstruction surgery. Following ACL reconstruction, neuromuscular deficits are present in both the surgical and nonsurgical limbs, and accurately predict second-ACL injury risk in adolescent athletes. While second ACL injury in highly active individuals may be predicated on a number of modifiable and nonmodifiable factors, clinicians have the greatest potential to address the modifiable postsurgical risk factors through targeted neuromuscular interventions. This manuscript will (1) summarize the neuromuscular deficits commonly identified at medical discharge to return to sport, (2) provide the evidence underlying second-ACL injury risk factors, (3) propose a method to assess the modifiable deficits related to second-ACL injury risk, and (4) outline a method of intervention to prevent second ACL injury. The program described in this clinical commentary was developed with consideration for the modifiable factors related to second-injury risk, the principles of motor learning, and careful selection of the exercises that may most effectively modify aberrant neuromuscular patterns. Future validation of this evidence-based, late-phase rehabilitation program may be a critical factor in maximizing return-to-activity success and reduction of second-injury risk in highly active individuals.

LEVEL OF EVIDENCE

Therapy, level 5.

Development of virtual reality proprioceptive rehabilitation system for stroke patients

In this study, the virtual reality (VR) proprioception rehabilitation system was developed for stroke patients to use proprioception feedback in upper limb rehabilitation by blocking visual feedback. To evaluate its therapeutic effect, 10 stroke patients (onset>3 month) trained proprioception feedback rehabilitation for one week and visual feedback rehabilitation for another week in random order. Proprioception functions were checked before, a week after, and at the end of training. The results show the click count, error distance and total error distance among proprioception evaluation factors were significantly reduced after proprioception feedback training compared to visual feedback training (respectively, p=0.005, p=0.001, and p=0.007). In addition, subjects were significantly improved in conventional behavioral tests after training. In conclusion, we showed the effectiveness and possible use of the VR to recover the proprioception of stroke patients.

Anterior-Posterior Instability of the Knee Following ACL Reconstruction with Bone-Patellar Tendon-Bone Ligament in Comparison with Four-Strand Hamstrings Autograft

Purpose. To evaluate anterior-posterior knee laxity using two different autografts. Material-Methods. 40 patients, (34 males and 6 women), 17-54 years old (mean: 31), were included in the present study. Group A (4SHS = 20) underwent reconstruction using four-strand hamstrings, and group B (BPBT = 20) underwent reconstruction using bone-patellar tendon-bone autograft. Using the KT-1000 arthrometer, knee instability was calculated in both knees of all patients preoperatively and 3, 6, and 12 months after surgery at the ACL-operated knee. The contralateral healthy knee was used as an internal control group. Results. Anterior-posterior instability using the KT1000 Arthrometer was found to be increased after ACL insufficiency. The recorded laxity improved after arthroscopic ACL reconstruction in both groups. However, statistically significant greater values were detected in the bone-patellar tendon-bone group, which revealed reduction of anteroposterior stability values to an extent, where no statistical significance with the normal values even after 3 months after surgery was observed. Conclusions. Anterior-Posterior instability of the knee improved significantly after arthroscopic ACL reconstruction. The bone-patellar tendon-bone graft provided an obvious greater stability.