Knee extensor strength, hop performance, patient-reported outcome and inter-test correlation in patients 9-12 months after anterior cruciate ligament reconstruction

Assessing the Relationship of Psychological Sport Readiness, Single-leg Vertical Jump, and Non-Sagittal Single-Leg Hops to Quadriceps Strength After Anterior Cruciate Ligament Reconstruction

Background

Limitations exist with current ACLR functional testing assessments that may be mitigated by including single-leg multi-directional testing.

Hypothesis/Purpose

To compare Anterior Cruciate Ligament-Return to Sport after Injury Scale (ACL-RSI) scores, limb symmetry index (LSI) of the single-leg vertical jump (SLVJ), single-leg medial rotation hop (SLMRH), single-leg lateral hop (SLLH), and isokinetic quadriceps strength between participants with an ACLR and healthy controls and assess predictors of quadriceps strength asymmetry. It was hypothesized that ACL-RSI scores and LSIs for all tests would differ between ACLR and healthy control groups and within the ACLR group a strong correlation would exist between all outcome measures and quadriceps strength.

Study Design

Cross-Sectional Study.

Methods

Twenty-six participants with an ACLR (median 13 months after surgery) and twenty-six matched healthy controls were recruited to participate in this study. Performance was assessed via SLVJ, SLMRH, SLLH, and isokinetic quadriceps strength. Between-group comparisons were made with independent t-tests and Mann-Whitney U test. Within the ACLR group, bivariate correlation and multivariate regression analysis were performed to assess the relationship between the outcome measures and quadriceps strength asymmetry.

Results

Significant between-limb differences were only identified in the ACLR group (p< 0.05): SLVJ LSI: 88.5%, SLMRH LSI: 93.6%, SLLH LSI: 92.7%, quadriceps strength LSI 80.9% - 83.9%, which were significantly lower (p <0.05) than the healthy control group. Within the ACLR group, a moderate-strong significant (p < 0.05) correlations existed with quadriceps strength and SLVJ (r=0.44-0.65), SLMRH (r =0.43-0.83), and SLLH (r=0.54-0.63); while ACL-RSI had a weak non-significant (p > 0.05) correlation with quadriceps strength (r= 0.12-0.30).

Conclusion

Single-leg multidirectional test LSIs were less in ACLR participants than matched healthy controls and all were directly related to quadriceps strength. Psychological readiness to return to sport was not related to quadriceps strength.

Double-Leg and Single-Leg Jump Test Reference Values for Athletes With and Without Anterior Cruciate Ligament Reconstruction Who Play Popular Pivoting Sports, Including Soccer and Basketball: A Scoping Review

OBJECTIVE: To synthesize and present reference values for double-leg and single-leg jump tests in healthy athletes who play pivoting sports, and athletes with anterior cruciate ligament reconstruction (ACLR) who play pivoting sports. DESIGN: Scoping review. LITERATURE SEARCH: We searched PubMed, the Cochrane Library, MEDLINE, Embase, and Web of Science until April 7, 2023. STUDY SELECTION CRITERIA: We included reference values in 2 different categories: (1) double-leg and/or single-leg jump test outcomes in pivoting-sport athletes with ACLR at a specific time point during rehabilitation, and (2) double-leg and/or single-leg jump test outcomes in healthy pivoting-sport athletes. DATA SYNTHESIS: We performed data synthesis for reference values from double-leg jump tests (squat jump and countermovement jump) and single-leg jump tests (vertical hop, single hop for distance, triple hop for distance, crossover hop for distance, medial triple hop for distance, lateral triple hop for distance, 6-m timed hop, side hop, drop jump, and 10-second repeated hop) that were performed according to a standardized test description. We summarized the data for type of sport, sex, sport participation level, and age group. RESULTS: Of the 27 included studies, nine reported reference values from healthy soccer players, six from healthy basketball players, and eleven from other healthy pivoting-sport athletes. LSI dominant/nondominant (LSI-D/ND) ranged between 97% and 106% for healthy soccer players, and between 99% and 120% for healthy basketball players. Four studies reported reference values from pivoting-sport athletes with ACLR from 7 to 10 months postsurgery. CONCLUSION: This scoping review summarizes double-leg and single-leg jump test reference values for athletes who play common pivoting sports, including soccer and basketball. J Orthop Sports Phys Ther 2024;54(6):1-14. Epub 20 March 2024. doi:10.2519/jospt.2024.12374.

Anterior Cruciate Ligament Return to Sport after Injury Scale (ACL-RSI) Scores over Time After Anterior Cruciate Ligament Reconstruction: A Systematic Review with Meta-analysis

BACKGROUND

Psychological readiness is an important consideration for athletes and clinicians when making return to sport decisions following anterior cruciate ligament reconstruction (ACLR). To improve our understanding of the extent of deficits in psychological readiness, a systematic review is necessary.

OBJECTIVE

To investigate psychological readiness (measured via the Anterior Cruciate Ligament-Return to Sport after Injury scale (ACL-RSI)) over time after ACL tear and understand if time between injury and surgery, age, and sex are associated with ACL-RSI scores.

METHODS

Seven databases were searched from the earliest date available to March 22, 2022. Articles reporting ACL-RSI scores after ACL tear were included. Risk of bias was assessed using the ROBINS-I, RoB-2, and RoBANS tools based on the study design. Evidence certainty was assessed for each analysis. Random-effects meta-analyses pooled ACL-RSI scores, stratified by time post-injury and based on treatment approach (i.e., early ACLR, delayed ACLR, and unclear approach).

RESULTS

A total of 83 studies were included in this review (78% high risk of bias). Evidence certainty was 'weak' or 'limited' for all analyses. Overall, ACL-RSI scores were higher at 3 to 6 months post-ACLR (mean = 61.5 [95% confidence interval (CI) 58.6, 64.4], I2 = 94%) compared to pre-ACLR (mean = 44.4 [95% CI 38.2, 50.7], I2 = 98%), remained relatively stable, until they reached the highest point 2 to 5 years after ACLR (mean = 70.7 [95% CI 63.0, 78.5], I2 = 98%). Meta-regression suggests shorter time from injury to surgery, male sex, and older age were associated with higher ACL-RSI scores only 3 to 6 months post-ACLR (heterogeneity explained R2 = 47.6%), and this reduced 1-2 years after ACLR (heterogeneity explained R2 = 27.0%).

CONCLUSION

Psychological readiness to return to sport appears to improve early after ACL injury, with little subsequent improvement until ≥ 2-years after ACLR. Longer time from injury to surgery, female sex and older age might be negatively related to ACL-RSI scores 12-24 months after ACLR. Due to the weak evidence quality rating and the considerable importance of psychological readiness for long-term outcomes after ACL injury, there is an urgent need for well-designed studies that maximize internal validity and identify additional prognostic factors for psychological readiness at times critical for return to sport decisions.

REGISTRATION

Open Science Framework (OSF), https://osf.io/2tezs/ .

The Influence of Strength and Sport Exposure on Psychological Readiness After ACL Reconstruction

BACKGROUND

Among young athletes returning to sport after anterior cruciate ligament reconstruction (ACLR), the extent to which psychological readiness is influenced by factors beyond the psychological domain is largely unknown.

HYPOTHESIS

Young athletes with recent sport exposure and higher quadriceps strength will demonstrate higher psychological readiness within 8 weeks of medical clearance to return to sport (RTS) after ACLR.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

A total of 38 young athletes after primary ACLR completed testing within 8 weeks of medical clearance to RTS. All participants completed isometric knee extension strength testing, in addition to the ACL Return to Sport after Injury (ACL-RSI) questionnaire. Athletes who participated in sport between time of medical clearance to RTS and date of study enrollment were categorized as SPORT-YES. Those who had not yet participated in sports were categorized as SPORT-NO. Multiple linear regression analyses were used to determine differences in ACL-RSI scores based on quadriceps strength and sport exposure status, while adjusting for age and sex.

RESULTS

Of the 38 participants, 20 (52.6%) were categorized as SPORT-YES. The regression model estimating overall ACL-RSI score (P < 0.01, adjusted R2 = 0.389) included significant independent contributions from age, sex, and sport exposure variables (age: P = 0.01, β [95% CI] = -2.01 [-3.54, -0.48]; sex (male): P = 0.02, β [95% CI] = 12.50 [2.36, 22.64]; strength: P = 0.51, β [95% CI] = -2.47 [-10.07,5.13]; sport exposure: P < 0.01, β [95% CI] = 12.89 [3.58, 22.19]).

CONCLUSION

In partial accordance with our hypothesis, recent sport exposure was significantly associated with higher ACL-RSI scores among young athletes in the weeks after medical clearance to RTS after ACLR, while quadriceps strength was not.

CLINICAL RELEVANCE

Future prospective work is needed to determine the existence and direction of causal relationships between exposure to sport environment and psychological readiness among young athletes after ACLR.

Asymmetric loading strategies during squats following anterior cruciate ligament reconstruction: A longitudinal investigation with curve analyses throughout and after rehabilitation

Investigations of kinetic asymmetries during bilateral squats following anterior cruciate ligament reconstruction (ACLR) are limited to mainly cross-sectional studies and discrete value data extracted at specific knee angles. We assessed loading asymmetries during squats longitudinally throughout rehabilitation using curve analysis and compared patient-reported outcome measures (PROMs) between those with and without asymmetry. Bodyweight squats were performed by 24 individuals (13 females) post-ACLR on three occasions: (1) Early 2.9 (1.1) months; (2) Mid 8.8 (3.1) months; (3) at Return to Sport (RTS) 13.1 (3.6) months; and 29 asymptomatic controls (22 females) once. Time-normalized between-leg asymmetry curves of sagittal plane hip, knee, and ankle moments and vertical ground reaction forces were compared using functional data analysis methods. Individual asymmetrical loading for ACLR was classified when exceeding the 95% confidence interval of controls during ≥50% of the squat. At Early, ACLR had greater asymmetry than controls for knee (15%-100% eccentric phase; 0%-100% concentric) and ankle flexion moments (56%-65% concentric). At Mid, ACLR had greater asymmetry for knee (41%-72% eccentric) and ankle flexion moments (56%-69% concentric). No between-group differences were found at RTS. From Early to RTS, ACLR reduced asymmetry for hip (21%-46% eccentric), knee (27%-58% concentric), and ankle flexion moments (21%-57% eccentric). At Early, 11/24 underloaded their ACLR knee and 1 overloaded compared with controls. At RTS, 4 underloaded and 6 overloaded. No differences in PROMs were found based on loading asymmetry. Beyond the early phase of rehabilitation from ACLR, individual-level analyses are required to reveal differing loading strategies during bilateral squats.

The Risk Factors and Preventive Strategies of Poor Knee Functions and Osteoarthritis after Anterior Cruciate Ligament Reconstruction: A Narrative Review

Anterior cruciate ligament reconstruction (ACLR) is the standard surgical treatment for ACL injury, which typically uses a graft to replace the torn ligament in the knee that uses small incisions with minimally invasive surgery. The optimal knee functions following ACLR depend on rehabilitation processes before and after the surgery. Knee function is the ability of the knee to perform various types of functional movements like walking, squatting, running, jumping, and pivoting where patients expect to achieve maximum knee function or at least more than 80% of its initial condition before the injury to avoid being categorized as poor knee function after ACLR. Patients use patient-reported outcome measures to collect data on their health status and quality of life after ACLR. Post-traumatic osteoarthritis (PTOA) is a type of OA that manifests in local cartilage injury caused by chondrocyte death, and matrix dispersion occurs following a joint injury like ACL injury. Gender, time from injury to surgery, and graft type were considered as risk factors for poor knee function after ACLR, while overweight, meniscus tear, and cartilage defect as risk factors for PTOA. However, age is an internal risk factor for both poor knee function and PTOA following ACLR. This review suggests several strategies to prevent both conditions, including a pre-operative program, comprehensive rehabilitation, body weight control, and return to sport (RTS) consideration based on physical capacity, proper time, and psychological readiness.

Reconsideration of Return-to-Sport Decision-Making After Pediatric ACL Injury: A Scoping Review

CONTEXT

Up to 90% of pediatric athletes return to sport (RTS) after anterior cruciate ligament reconstruction (ACL-R); however, <50% RTS at the same level and second ACL injury rates are up to 32%.

OBJECTIVES

(1) Determine which physical and patient-reported outcome measures guide clinical decision-making on RTS in pediatric athletes after ACL-R and (2) present a framework with insights from cognitive and neurophysiological domains to enhance rehabilitation outcomes.

DATA SOURCES

PubMed, CINAHL, Embrase, and Cochrane library databases and gray literature.

STUDY SELECTION

Data on pediatric (<18 years) ACL-R patients, RTS, tests, and decision-making were reported in 1214 studies. Two authors independently reviewed titles and abstract, excluding 962 studies. Gray literature and cross-reference checking resulted in 7 extra studies for full-text screening of 259 studies. Final data extraction was from 63 eligible studies.

STUDY DESIGN

Scoping review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

Details on study population, aims, methodology, intervention, outcome measures, and important results were collected in a data chart.

RESULTS

Studies included 4456 patients (mean age, 14 years). Quadriceps and hamstring strength (n = 25), knee ligament arthrometer (n = 24), and hop tests (n = 22) were the most-reported physical outcome measures guiding RTS in <30% of studies with cutoff scores of limb symmetry index (LSI) ≥85% or arthrometer difference <3 mm. There were 19 different patient-reported outcome measures, most often reporting the International Knee Documentation Committee (IKDC) (n = 24), Lysholm (n = 23), and Tegner (n = 15) scales. Only for the IKDC was a cutoff value of 85% reported.

CONCLUSION

RTS clearance in pediatric ACL-R patients is not based on clear criteria. If RTS tests were performed, outcomes did not influence time of RTS. Postoperative LSI thresholds likely overestimate knee function since biomechanics are impaired despite achieving RTS criteria. RTS should be considered a continuum, and biomechanical parameters and contextual rehab should be pursued with attention to the individual, task, and environment. There is a need for psychological monitoring of the ACL-R pediatric population.

Combining age, sex, body mass index, sport level, and preoperative quadriceps strength improves the predictive ability of quadriceps strength recovery after anterior cruciate ligament reconstruction

PURPOSE

This study compared the predictive ability of each independent predictor with that of a combination of predictors for quadriceps strength recovery one year after anterior cruciate ligament (ACL) reconstruction.

METHODS

Patients who underwent primary ACL reconstruction using hamstring autografts were enrolled. Quadriceps strength, hamstring strength, and anterior tibial translation were measured, and the limb symmetry index (LSI) of the quadriceps and the hamstrings was calculated preoperatively and one year after surgery. Patients were classified into two groups according to the LSI of the quadriceps strength at one year postoperatively (≥ 80% or < 80%). Multivariate logistic regression analysis identified the independent predictors of quadriceps strength recovery, and the cut-off value was calculated using the receiver operating characteristic curve. A model assessing predictive ability of the combination of independent predictors was created, and the area under the curve (AUC) for each independent predictor was calculated by using the receiver-operating characteristic curves and the DeLong method.

RESULTS

Of the 646 patients, 414 (64.1%) had an LSI of at least 80% for quadriceps strength one year after surgery, and 232 patients (35.9%) had an LSI of < 80%. Age, sex, body mass index (BMI), preinjury sport level, and LSI of preoperative quadriceps strength were independently associated with quadriceps strength recovery one year after ACL reconstruction. The cut-off values were age: 22.5 years; sex: female; BMI: 24.3 kg/m2; preinjury sport level: no sport; and LSI of preoperative quadriceps strength: 63.3%. The AUC of the model assessing the predictive ability of the combination of age, sex, BMI, preinjury sport level, and LSI of preoperative quadriceps strength was significantly higher (0.73) than that of similar factors of preoperative quadriceps strength (AUC: 0.63, 0.53, 0.56, 0.61, and 0.68, p < 0.01, respectively).

CONCLUSION

The combination of age, sex, BMI, preinjury sport level, and LSI of preoperative quadriceps strength had a superior predictive ability for quadriceps strength recovery at one year after ACL reconstruction than these predictors alone. Multiple factors, including patient characteristics and preoperative quadriceps strength, should be considered when planning rehabilitation programs to improve quadriceps strength recovery after ACL reconstruction.

LEVEL OF EVIDENCE

III.

It is time to target psychological readiness (or lack of readiness) in return to sports after Anterior Cruciate Ligament tears

Functional recovery has for long been the focus of rehabilitation after an Anterior Cruciate Ligament (ACL) injury. It is now increasingly recognized that more attention should be given to patients` mental recovery, their psychological readiness for returning to sport, after such an injury. Within this relatively new field of science, clinicians need clarity on when and how psychological factors should be monitored and how inexpedient psychological responses may be addressed during rehabilitation. In this Expert Opinion suggestions on how targeting psychological readiness may improve rehabilitation and return-to-sport evaluations are made based on current evidence-and issues in need of further clarification are addressed.

Development and Reliability of a Visual-Cognitive Reactive Triple Hop Test

CONTEXT

Current lower-extremity return to sport testing primarily considers the physical status of an athlete; however, sport participation requires continuous cognitive dual-task engagement. Therefore, the purpose was to develop and evaluate the reliability of a visual-cognitive reactive (VCR) triple hop test that simulates the typical sport demand of combined online visual-cognitive processing and neuromuscular control to improve return to sport testing after lower-extremity injury.

DESIGN

Test-retest reliability.

METHODS

Twenty-one healthy college students (11 females, 23.5 [3.7] y, 1.73 [0.12] m, 73.0 [16.8] kg, Tegner Activity Scale 5.5 [1.1] points) participated. Participants performed a single-leg triple hop with and without a VCR dual task. The VCR task incorporated the FitLight system to challenge peripheral response inhibition and central working memory. Maximum hop distance, reaction time, cognitive errors, and physical errors were measured. Two identical testing visits were separated by 12 to 17 days (14 [1] d).

RESULTS

Traditional triple hop (intraclass correlation coefficients: ICC(3,1) = .96 [.91-.99]; standard error of the measurement = 16.99 cm) and the VCR triple hop (intraclass correlation coefficients(3,1) = .92 [.82-.97]; standard error of the measurement = 24.10 cm) both demonstrated excellent reliability for the maximum hop distance, and moderate reliability for the VCR triple hop reaction time (intraclass correlation coefficients(3,1) = .62 [.09-.84]; standard error of the measurement = 0.09 s). On average, the VCR triple hop resulted in a hop distance deficit of 8.17% (36.4 [5.1] cm; P < .05, d = 0.55) relative to the traditional triple hop.

CONCLUSIONS

Hop distance on the VCR triple hop had excellent test-retest reliability and induced a significant physical performance deficit when compared with the traditional triple hop assessment. The VCR triple hop reaction time also demonstrated moderate reliability.

Early ACL reconstruction shows an improved recovery of isokinetic thigh muscle strength compared to delayed or chronic cases

INTRODUCTION

The recovery of periarticular strength is a major criterion in return-to-play testing. The rationale of the study was to assess the impact of the delay of surgery (∆ between injury and surgery) on knee extensor and knee flexor strength of anterior cruciate ligament (ACL)-deficient patients six months after reconstruction.

MATERIALS AND METHODS

In a retrospective cohort study, all patients with ACL ruptures between 03/2015 and 12/2019 were analyzed. Inclusion criteria were isolated ACL rupture without any associated lesions undergoing a reconstruction using ipsilateral hamstring tendon autograft and adherence to isokinetic strength testing before and at 5-7 months postoperatively. These patients were then clustered into three groups: EARLY reconstruction (∆ < 42 days), DELAYED reconstruction (∆42-180d), and CHRONIC (∆ > 180d). Knee extensor and flexor strength of the ipsi- and contralateral leg were analyzed by concentric isokinetic measurement (60°/s). Primary outcomes were the maximal knee extension and flexion torque, hamstrings-to-quadriceps ratio (H/Q) ratio), and the corresponding limb symmetry indices.

RESULTS

n = 444 patients met the inclusion criteria. From EARLY to DELAYED to CHRONIC, a progressive reduction in postoperative strength performance was observed in knee extension (1.65 ± 0.45 to 1.62 ± 0.52 to 1.51 ± 0.5 Nm/kg resp.) and flexion (1.22 ± 0.29 to 1.18 ± 0.3 to 1.13 ± 0.31 Nm/kg resp.) strength on the ACL reconstructed leg. This general loss in periarticular strength was already apparent in the preoperative performance even on the healthy side. When controlling for the preoperative performance using ANCOVA analysis, EARLY performed significantly better than DELAYED (extension p = 0.001, flexion p = .02) and CHRONIC (extension p = 0.005, flexion p < 0.001). Also, there were significantly higher values for H/Q ratio in the injured leg across all groups where the H/Q ratio increased from EARLY to CHRONIC and from pre- to postoperative values.

CONCLUSIONS

With respect to the force generating capacity when returning-to-play, it is advantageous to seek for an early ACL reconstruction within the first 12 weeks after the injury. The increasing loss of thigh muscle strength observed in delayed or chronic cases affects the injured and also the non-injured leg.

LEVEL OF EVIDENCE

III, retrospective cohort study.

The Need To Change Return to Play Testing in Athletes Following ACL Injury: A Theoretical Model

The incidence of knee injuries in sport, particularly involving the ACL, appears to be increasing yearly, especially in younger age athletes. Even more concerning is the frequency of ACL reinjury also appears to be increasing year after year. Improving the objective criteria and testing methods used to determine return to play (RTP) readiness following ACL surgery is one aspect of the rehabilitation process that can significantly help in reducing reinjury rates. Currently, the majority of clinicians are still using post operative time frames as their number one criterion for clearance to RTP. This flawed method demonstrates an inadequate reflection of the true unpredictable, dynamic environment athletes are returning to participate in. In our clinical experience, objective testing to allow for clearance to sport participation following an ACL injury should incorporate neurocognitive and reactive testing due to the nature of the injury typically occurs because of failed control of unanticipated reactive movements. The purpose of this manuscript is to share a neurocognitive testing sequence we currently employ consisting of 8 tests in 3 categories: Blazepod tests, reactive shuttle run tests, and reactive hop tests. The use of a more dynamic reactive testing battery may decrease the reinjury rates when an athlete is cleared for participation by measuring readiness in chaotic circumstances that are more truly reflective of the sporting environment the athlete is working to return to and in the process give them a greater sense of confidence.

Return to sport soccer after anterior cruciate ligament reconstruction: ISAKOS consensus

INTRODUCTION

Many factors can affect the return to pivoting sports, after an Anterior Cruciate Ligament Reconstruction. Prehabilitation, rehabilitation, surgical and psychological aspects play an essential role in the decision to return to sports. The purpose of this study is to reach an international consensus about the best conditions for returning to sports in soccer-one of the most demanding level I pivoting sports after anterior cruciate ligament (ACL) reconstruction.

METHODS

34 International experts in the management of ACL injuries, representing all the Continents were convened and participated in a process based on the Delphi method to achieve a consensus. 37 statements related to ACL reconstruction were reviewed by the experts in three rounds of surveys in complete anonymity. The statements were prepared by the working group based on previous literature or systematic reviews. Rating agreement through a Likert Scale: strongly agree, agree, neither agree or disagree, disagree and strongly disagree was used. To define consensus, it was established that the assertions should achieve a 75% of agreement or disagreement.

RESULTS

Of the 37 statements, 10 achieved unanimous consensus, 18 non-unanimous consensus and 9 did not achieve consensus. In the preoperative, the correction of the range of motion deficit, the previous high level of participation in sports and a better knowledge of the injury by the patient and compliance to participate in Rehabilitation were the statements that reached unanimous consensus. During the surgery, the treatment of associated injuries, as well as the use of autografts, and the addition of a lateral extra-articular tenodesis in some particular cases (active young athletes, <25 years old, hyperlaxity, high rotatory laxity and revision cases) obtained also 100% consensus. In the postoperative period, psychological readiness and its validation with scales, adequate physical preparation, as well as not basing the RTSS purely on the time of evolution after surgery, were the factors that reached unanimous Consensus.

CONCLUSIONS

The consensus statements derived from this international ISAKOS leaders, may assist clinicians in deciding when to return to sports soccer in patients after an ACL reconstruction. Those statements that reached 100% consensus have to be strongly considered in the final decision to RTS soccer.

Measurement properties for muscle strength tests following anterior cruciate ligament and/or meniscus injury: What tests to use and where do we need to go? A systematic review with meta-analyses for the OPTIKNEE consensus

Objectives

Critically appraise and summarise the measurement properties of knee muscle strength tests after anterior cruciate ligament (ACL) and/or meniscus injury using the COnsensus-based Standards for the selection of health Measurement INstruments Risk of Bias checklist.

Design

Systematic review with meta-analyses. The modified Grading of Recommendations Assessment, Development and Evaluation-guided assessment of evidence quality.

Data sources

Medline, Embase, CINAHL and SPORTSDiscus searched from inception to 5 May 2022.

Eligibility criteria for selecting studies

Studies evaluating knee extensor or flexor strength test reliability, measurement error, validity, responsiveness or interpretability in individuals with ACL and/or meniscus injuries with a mean injury age of ≤30 years.

Results

Thirty-six studies were included involving 31 different muscle strength tests (mode and equipment) in individuals following an ACL injury and/or an isolated meniscus injury. Strength tests were assessed for reliability (n=8), measurement error (n=7), construct validity (n=27) and criterion validity (n=7). Isokinetic concentric extensor and flexor strength tests were the best rated with sufficient intrarater reliability (very low evidence quality) and construct validity (moderate evidence quality). Isotonic extensor and flexor strength tests showed sufficient criterion validity, while isometric extensor strength tests had insufficient construct and criterion validity (high evidence quality).

Conclusion

Knee extensor and flexor strength tests of individuals with ACL and/or meniscus injury lack evidence supporting their measurement properties. There is an urgent need for high-quality studies on these measurement properties. Until then, isokinetic concentric strength tests are most recommended, with isotonic strength tests a good alternative.

Development and reliability of a visual-cognitive medial side hop for return to sport testing

OBJECTIVES

To develop and evaluate the reliability of a new visual-cognitive medial side hop (VCMH) test that challenges physical and cognitive performance to potentially improve return to sport testing.

DESIGN

Test-retest experimental design.

SETTING

Laboratory.

PARTICIPANTS

Twenty-two healthy college students participated (11 females; 23.5 ± 3.64 years; 172.9 ± 11.58 cm; 74.1 ± 17.25 kg; Tegner Score 5.6 ± 1.1).

MAIN OUTCOME MEASURES

Subjects performed a medial side hop for distance with and without a visual-cognitive task (VCMH). Maximum hop distance and cognitive errors were measured.

RESULTS

There was strong reliability for the traditional medial side hop (ICC3,1 = 0.88[0.72, 0.95]; SEM = 7.16 cm) and VCMH distances (ICC3,1 = 0.86[0.66, 0.94]; SEM = 6.82 cm). Maximum hop distance was significantly lower during the VCMH (86.9 ± 18.2 cm) compared to the traditional medial side hop (96.3 ± 20.7 cm; p < 0.05; d = 0.74), with a performance deficit of 9.69%.

CONCLUSION

The VCMH has high test-retest reliability and resulted in a significant dual-task cost with a reduction in physical performance when compared to the traditional medial side hop.

Identification and Predictors of Age-Relevant and Activity-Relevant Hop Test Targets in Young Athletes After Anterior Cruciate Ligament Reconstruction

CONTEXT

Performance symmetry between limbs (limb symmetry index [LSI] ≥ 90%) on a battery of single-leg hop tests is recommended to inform return-to-sport (RTS) decisions after anterior cruciate ligament (ACL) reconstruction (ACLR). Achieving current hop test symmetry values has not been associated with future clinical outcomes. The identification of age-relevant and activity-relevant target values to benchmark the hop test performance of young athletes post-ACLR may provide greater specificity and clinical relevance for interpretation of hop test data.

OBJECTIVE

To identify single-leg hop test-target values for individual-limb performance and symmetry between limbs for athletes without a history of ACL injury and evaluate the proportion of young athletes post-ACLR who met the newly derived target values at the time of RTS clearance. The secondary objective was to test the hypothesis that better function and strength would be associated with achieving the newly derived hop test target values.

DESIGN

Cross-sectional study.

SETTING

Pediatric medical center and academic medical center.

PATIENTS OR OTHER PARTICIPANTS

A total of 159 young athletes (age = 16.9 ± 2.2 years) at the time of RTS clearance after primary, unilateral ACLR and 47 uninjured control athletes (age = 17.0 ± 2.3 years).

MAIN OUTCOME MEASURE(S)

All participants completed a single-leg hop test battery (single hop, triple hop, and crossover hop for distance [cm], and 6-m timed hop [seconds]). Raw distance values were normalized by body height, and LSI (%) was calculated for each hop test. Target values were defined as the lower bound of the 95% CI for each hop test, using control group data. Participants with ACLR also completed the Knee injury and Osteoarthritis Outcome Score subscales and a quadriceps femoris strength (newton meters/kilogram) assessment. Logistic regression determined predictors of achieving hop test target values in the ACLR group among injury, function, and strength data (P < .05).

RESULTS

In the ACLR group, 79% to 84% of participants met the 90% LSI threshold on each hop test. They achieved the target values for surgical-limb performance in the following proportions (% participants): single hop = 29%, triple hop = 24%, crossover hop = 30%, 6-m timed hop = 18%, all hops= 12%. Also, they met the target values for LSI in the following proportions: single hop = 43%, triple hop = 48%, crossover hop = 50%, 6-m timed hop = 69%, all hops = 25%. The only predictor of achieving all hop test targets for surgical-limb performance was greater surgical-limb quadriceps femoris strength (odds ratio = 4.10, P = .007). We noted a trend toward quadriceps femoris strength LSI ≥ 90% (odds ratio = 2.44, P = .058) as a predictor for meeting all hop test symmetry targets.

CONCLUSIONS

At the time of RTS post-ACLR, only a small proportion of young athletes achieved the age-relevant and activity-relevant single-leg hop test targets for surgical-limb performance or symmetry between limbs, even though a majority met the traditionally recommended 90% LSI threshold on hop tests.

What tests should be used to assess functional performance in youth and young adults following anterior cruciate ligament or meniscal injury? A systematic review of measurement properties for the OPTIKNEE consensus

OBJECTIVES

To critically appraise and summarise measurement properties of functional performance tests in individuals following anterior cruciate ligament (ACL) or meniscal injury.

DESIGN

Systematic review.

DATA SOURCES

Systematic searches were performed in Medline (Ovid), Embase (Ovid), CINAHL (EBSCO) and SPORTSDiscus (EBSCO) on 7 July 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies evaluating at least one measurement property of a functional performance test including individuals following an ACL tear or meniscal injury with a mean injury age of ≤30 years. The COnsensus-based Standards for the selection of health Measurement INstruments Risk of Bias checklist was used to assess methodological quality. A modified Grading of Recommendations Assessment, Development and Evaluation assessed evidence quality.

RESULTS

Thirty studies evaluating 26 functional performance tests following ACL injury were included. No studies were found in individuals with an isolated meniscal injury. Included studies evaluated reliability (n=5), measurement error (n=3), construct validity (n=26), structural validity (n=1) and responsiveness (n=1). The Single Leg Hop and Crossover Hop tests showed sufficient intrarater reliability (high and moderate quality evidence, respectively), construct validity (low-quality and moderate-quality evidence, respectively) and responsiveness (low-quality evidence).

CONCLUSION

Frequently used functional performance tests for individuals with ACL or meniscal injury lack evidence supporting their measurement properties. The Single Leg Hop and Crossover Hop are currently the most promising tests following ACL injury. High-quality studies are required to facilitate stronger recommendations of performance-based outcomes following ACL or meniscal injury.

Selective bundle reconstruction for symptomatic partial anterior cruciate ligament tears demonstrates good functional scores, high return to sport rates and a low re-tear rate

BACKGROUND

The treatment of symptomatic partial anterior cruciate ligament (ACL) tears remains controversial. This study investigated the clinical and functional outcome of patients undergoing selective posterolateral (PLB) or anteromedial (AMB) bundle reconstruction.

METHODS

55 consecutive patients underwent partial bundle reconstruction, of which 45 (AMB = 17, PLB = 28) were included in the current analysis (62% male, mean age of 29.1 years). Patients were assessed at 12 and 24 months with patient-reported outcome measures (PROMs), graft laxity (KT-1000), knee extensor and flexor torque and a 4-hop battery. Limb Symmetry Indices (LSIs) were calculated. Return to sport (RTS) rates, re-operations and re-injuries were evaluated.

RESULTS

High scoring PROMs were evident, with 62% and 84% of patients participating in pivoting sports at 12 and 24 months, respectively. Overall, 98% of patients demonstrated 'normal' knee laxity at 24 months. Mean LSIs for all hop tests were ≥ 90% at 12 and 24 months, with 76-87% of patients demonstrating LSIs ≥ 90% on the four hop tests employed at 12 months, which was 89-93% of patients at 24 months. A mean knee extensor torque LSI of 89% and 97% was observed at 12 and 24 months. Two ipsilateral re-tears (2/55, 3.6%, AMB = 1, PLB = 1) were observed over the 24-month period, with no contralateral ACL tears.

CONCLUSIONS

High levels of physical function and RTS were observed in patients following partial bundle reconstruction, higher than that reported in the literature in patients undergoing ACLR, without evidence of instability and a low re-injury rate.

Can the Eight Hop Test Be Measured with Sensors? A Systematic Review

Rehabilitation aims to increase the independence and physical function after injury, surgery, or other trauma, so that patients can recover to their previous ability as much as possible. To be able to measure the degree of recovery and impact of the treatment, various functional performance tests are used. The Eight Hop Test is a hop exercise that is directly linked to the rehabilitation of people suffering from tendon and ligament injuries on the lower limb. This paper presents a systematic review on the use of sensors for measuring functional movements during the execution of the Eight Hop Test, focusing primarily on the use of sensors, related diseases, and different methods implemented. Firstly, an automated search was performed on the publication databases: PubMed, Springer, ACM, IEEE Xplore, MDPI, and Elsevier. Secondly, the publications related to the Eight-Hop Test and sensors were filtered according to several search criteria and 15 papers were finally selected to be analyzed in detail. Our analysis found that the Eight Hop Test measurements can be performed with motion, force, and imaging sensors.

Isometric dynamometry, dependent on knee angle, is a suitable alternative to isokinetic dynamometry when evaluating quadriceps strength symmetry in patients following anterior cruciate ligament reconstruction

BACKGROUND

Knee extensor strength deficits increase re-injury risk following anterior cruciate ligament reconstruction (ACLR). This study investigated whether isometric strength testing methods are a suitable alternative to isokinetic assessment for identifying knee extensor strength asymmetry.

METHODS

This study recruited 22 patients at 9-12 months after ACLR and 22 healthy controls. The single hop for distance (SHD) and knee extensor strength via isokinetic (60°/s and 120°/s) and isometric (positions of 90°, 60° and 30° of flexion, from full knee extension) methods were assessed. Absolute scores (normalized to body weight) and limb symmetry indices (LSIs) were calculated, with t-tests employed for statistical comparisons.

RESULTS

The SHD LSI was significantly higher (p < 0.01) than both isokinetic speeds and the 30° isometric position. No significant LSI differences (p > 0.01) existed within isokinetic or isometric test conditions. In ACLR patients, only the 60°/s isokinetic condition was significantly lower (p = 0.005) than the 60° isometric condition. When normalized to body weight, the operated limb in ACLR patients was significantly weaker than the non-operated limb during peak isokinetic strength testing at 60°/s (p = 0.001) and 120°/s (p = 0.010), as well as isometric testing at 30° (p = 0.009). Compared with controls, ACLR patients demonstrated significantly lower (p < 0.01) mean LSIs across most measures.

CONCLUSIONS

Assessment of knee extensor strength via isometric methods appears suitable in the absence of isokinetic testing equipment, though consideration of test angle (30° and 90° knee angles better detect asymmetries similar to isokinetic testing) is important.

Effects of a Targeted Exercise Program on Inter-Leg Asymmetries in Patients with Patellofemoral Pain

Patellofemoral pain (PFP) is often associated with impaired muscle strength, flexibility, and stability. It has been suggested that inter-leg asymmetries have an important role in increasing the risk of musculoskeletal injuries, including PFP. Thus, the aim of this study was to identify significant asymmetries and determine the effects of a symmetry targeted exercise program in patients with PFP. Eighteen patients aged 13 to 54 years (24.17 ± 12.52 years) with PFP participated in this study. Strength, flexibility and stability outcomes of the trunk, hip, knee and ankle muscles were assessed. A single-group pretest–posttest design was used to assess changes in inter-leg and agonist–antagonist asymmetries resulting from the 8-week period of the supervised exercise program. Results indicated a significant improvement in inter-leg symmetry regarding bilateral stance in a semi-squat position (p = 0.020, d = 0.61, df = 17) and ankle plantarflexion (p = 0.003, d = 0.32, df = 17) and ankle dorsiflexion strength (p < 0.001, d = 0.46, df = 17). In addition, the ratio of ankle dorsiflexion/plantarflexion (p = 0.036, d = 1.14, df = 17) and hip extension/flexion (p = 0.031, d = 0.94, df = 16) changed significantly during the intervention period. To our knowledge, this was the first study to evaluate inter-leg asymmetries resulting from a period of a supervised exercise program. The results indicate that an exercise program focusing on individual asymmetries may influence specific deficits and contribute to better rehabilitation outcomes.