Self-reported outcomes are associated with knee strength and functional symmetry in individuals who have undergone anterior cruciate ligament reconstruction with hamstring tendon autograft

No sign of weakness: a systematic review and meta-analysis of hip and calf muscle strength after anterior cruciate ligament injury

OBJECTIVE

We aimed to determine hip and lower-leg muscle strength in people after ACL injury compared with an uninjured control group (between people) and the uninjured contralateral limb (between limbs).

DESIGN

Systematic review with meta-analysis.

DATA SOURCES

MEDLINE, EMBASE, CINAHL, Scopus, Cochrane CENTRAL and SportDiscus to 28 February 2023.

ELIGIBILITY CRITERIA

Primary ACL injury with mean age 18-40 years at time of injury. Studies had to measure hip and/or lower-leg muscle strength quantitatively (eg, dynamometer) and report muscle strength for the ACL-injured limb compared with: (i) an uninjured control group and/or (ii) the uninjured contralateral limb. Risk of bias was assessed according to Cochrane Collaboration domains.

RESULTS

Twenty-eight studies were included (n=23 measured strength ≤12 months post-ACL reconstruction). Most examined hip abduction (16 studies), hip extension (12 studies) and hip external rotation (7 studies) strength. We found no meaningful difference in muscle strength between people or between limbs for hip abduction, extension, internal rotation, flexion or ankle plantarflexion, dorsiflexion (estimates ranged from -9% to +9% of comparator). The only non-zero differences identified were in hip adduction (24% stronger on ACL limb (95% CI 8% to 42%)) and hip external rotation strength (12% deficit on ACL limb (95% CI 6% to 18%)) compared with uninjured controls at follow-ups >12 months, however both results stemmed from only two studies. Certainty of evidence was very low for all outcomes and comparisons, and drawn primarily from the first year post-ACL reconstruction.

CONCLUSION

Our results do not show widespread or substantial muscle weakness of the hip and lower-leg muscles after ACL injury, contrasting deficits of 10%-20% commonly reported for knee extensors and flexors. As it is unclear if deficits in hip and lower-leg muscle strength resolve with appropriate rehabilitation or no postinjury or postoperative weakness occurs, individualised assessment should guide training of hip and lower-leg strength following ACL injury.

PROSPERO REGISTRATION NUMBER

CRD42020216793.

The NordBord test reveals persistent knee flexor strength asymmetry when assessed two and five years after ACL reconstruction with hamstring tendon autograft

OBJECTIVE

Comparison of knee flexor strength limb symmetry index (LSI) between the NordBord-test and the Biodex-test, and to determine the relationship between knee flexor strength and function in patients 2 and 5 years after anterior cruciate ligament reconstruction (ACL-R) with hamstring tendon (HT) autografts.

DESIGN

Observational registry study.

SETTING

Primary care.

PATIENTS

Cross-sectional data from 96 patients (55% women) participating in a rehabilitation-registry after ACL-R with HT autografts.

MAIN OUTCOME MEASURES

Comparison of knee flexor strength symmetry between the Biodex-test and the NordBord-test. Secondly, the relationship between knee flexor strength test and perceived knee function, activity level, and hop performance.

RESULTS

The NordBord-test demonstrated greater strength deficits compared to the Biodex-test with a mean difference of 12.5% ± 15.1% 95 % CI [8.1; 16.9%] at 2 years, and 11.1% ± 11.9% 95 % CI [7.7; 14.6 %] at 5 years after ACL-R. Relative concentric knee flexor strength (Nm/kg) in the Biodex demonstrated significant weak-to-moderate correlations with activity level and hop performance (r = 0.33-0.67) at 2 and 5 years.

CONCLUSION

The NordBord-test identified deficits in knee flexor strength LSI not seen with the Biodex-test at 2 and 5 years after ACL-R. No significant correlations were found between the persistent knee flexor strength asymmetry and perceived function, activity level or hop performance.

Restoring Knee Flexor Strength Symmetry Requires 2 Years After ACL Reconstruction, But Does It Matter for Second ACL Injuries? A Systematic Review and Meta-analysis

BACKGROUND

It is unknown whether knee flexor strength recovers after anterior cruciate ligament (ACL) reconstruction with a hamstring tendon (HT) autograft and whether persistent knee flexor strength asymmetry is associated to a second ACL injury.

OBJECTIVE

We aimed to systematically review (1) whether knee flexor strength recovers after ACL reconstruction with HT autografts, and (2) whether it influences the association with a second ACL injury. A third aim was to summarize the methodology used to assess knee flexor strength.

DESIGN

Systematic review and meta-analysis reported according to PRISMA.

METHODS

A systematic search was performed using the Cochrane Library, Embase, Medline, PEDRo, and AMED databases from inception to December 2021 and until completion in January 2023. Human clinical trials written in English and conducted as randomized controlled trials, longitudinal cohort, cross-sectional, and case-control studies on patients with index ACL reconstructions with HT autografts harvested from the ipsilateral side were considered. Knee flexor strength was measured isokinetically in both the reconstructed and uninjured limb to enable the calculation of the limb symmetry index (LSI). The Risk of Bias Assessment Tool for Non-Randomized Studies was used to assess risk of bias for non-randomized studies and the revised Cochrane Risk of Bias tool was used for randomized controlled trials. For the meta-analysis, the LSI (mean ± standard error) for concentric knee flexor strength at angular velocities of 60°/second (s) and 180°/s preoperatively and at 3 months, 6 months, 12 months, and 24 months were pooled as weighted means with standard errors.

RESULTS

The search yielded 64 studies with a total of 8378 patients, which were included for the assessment of recovery of knee flexor strength LSI, and a total of 610 patients from four studies that investigated the association between knee flexor strength and second ACL injuries. At 1 year after ACL reconstruction, the knee flexor strength LSI had recovered to 89.0% (95% CI 87.3; 90.7%) and 88.3% (95% CI 85.5; 91.1%) for the velocities of 60°/s and 180°/s, respectively. At 2 years, the LSI was 91.7% (95% CI 90.8; 92.6%) and 91.2% (95% CI 88.1; 94.2%), for velocities of 60°/s and 180°/s, respectively. For the association between knee flexor strength and second ACL injuries, there was insufficient and contradictory data.

CONCLUSIONS

There was low to very low certainty of evidence indicating that the recovery of knee flexor strength LSI, defined as ≥ 90% of the uninjured side, takes up to 2 years after ACL reconstruction with HT autografts. Whether knee flexor strength deficits influence the association of second ACL injuries is still uncertain. There was considerable heterogeneity in the methodology used for knee flexor strength assessment, which together with the low to very low certainty of evidence, warrants further caution in the interpretation of our results.

REGISTRATION NUMBER

CRD42022286773.

Sports activity level after ACL reconstruction is predicted by vastus medialis or vastus medialis obliquus thickness, single leg triple hop distance or 6-m timed hop, and quality of life score

PURPOSE

Recovery after anterior cruciate ligament reconstruction (ACLR) may take > 2 years, and younger athletes have higher re-injury risk. The purpose of this prospective longitudinal study was to determine how the early to mid-term Tegner Activity Level Scale (TALS) scores of athletically active males ≥ 2 years post-ACLR follow-up was predicted by bilateral isokinetic knee extensor and flexor torque, quadriceps femoris thickness, single leg hop test performance, and self-reported knee function (Knee Injury and Osteoarthritis Outcome Score (KOOS); International Knee Documentation Committee (IKDC) Subjective Assessment score).

METHODS

After ACLR with a hamstring tendon autograft and safely returning to sports at least twice weekly, 23 men (18.4 ± 3.5 years of age) were evaluated at final follow-up (mean = 4.5, range = 2-7 years). Exploratory forward stepwise multiple regression was used to determine the relationship between independent surgical and non-surgical lower limb variables peak concentric isokinetic knee extensor-flexor torque at 60°/sec and 180°/sec, quadriceps femoris muscle thickness, single leg hop test profile results, KOOS subscale scores, IKDC Subjective Assessment scores, and time post-ACLR on TALS scores at final follow-up.

RESULTS

Subject TALS scores were predicted by KOOS quality of life subscale score, surgical limb vastus medialis obliquus (VMO) thickness, and surgical limb single leg triple hop for distance (SLTHD) performance. Subject TALS scores were also predicted by KOOS quality of life subscale score, non-surgical limb vastus medialis (VM) thickness, and non-surgical limb 6 m single leg timed hop (6MSLTH) performance.

CONCLUSION

TALS scores were influenced differently by surgical and non-surgical lower extremity factors. At ≥ 2 years post-ACLR, ultrasound VM and VMO thickness measurements, single leg hop tests that challenge knee extensor function, and self-reported quality of life measurements predicted sports activity levels. The SLTHD test may be better than the 6MSLTH for predicting long-term surgical limb function.

Association between quadriceps muscle thickness and knee function in anterior cruciate ligament reconstructed athletes: a cross-sectional study

OBJECTIVE

This study aimed to investigate the association between vastus medialis obliquus (VMO), rectus femoris (RF), and vastus lateralis (VL) muscle thickness and quadriceps isokinetic strength, single-leg hop performance, and self-reported knee function in male athletes who had undergone anterior cruciate ligament reconstruction (ACLR).

METHODS

Forty-two male athletes [mean ± standard deviation, age: 21.4 ± 3.4 years], who had undergone ACLR and had cleared to return to activity, were included in this study. Real-time ultrasound images of VMO, RF, and VL thicknesses were obtained from both reconstructed and contralateral limbs. Concentric quadriceps peak torque at 60°/s and 180°/s, single-leg hop for Distance (SLHD), and self-reported knee function scores were also assessed. Linear regression analysis and student t tests were used for statistical analysis.

RESULTS

In reconstructed limb, greater VMO, RF, and VL thicknesses were associated with greater quadriceps peak torque at 60°/s (p = .008, r2 = 0.46) and at 180°/s (p = .006, r2 = 0.47). Greater quadriceps thickness was related to greater SLHD score in reconstructed limb (p = .002, r2 = 0.21). Self-reported knee function scores were not related to quadriceps thickness. VMO, RF, and VL thicknesses were smaller in reconstructed limb compared to contralateral limb (p < .001, p = .01, and p = .002, respectively).

CONCLUSION

Quadriceps thickness by using ultrasound was associated with concentric quadriceps strength and single-leg hop distance in individuals who had undergone ACLR. However, quadriceps thickness was not related to self-reported knee function. The ultrasonography may be included in the evaluation of the knee function after ACLR, and it may be a useful and easy method in the follow-up of the quadriceps strength recovery following ACLR.

Is absolute or relative knee flexor strength related to patient-reported outcomes in patients treated with ACL reconstruction with a hamstring tendon autograft? An analysis of eccentric Nordic hamstring strength and seated concentric isokinetic strength

BACKGROUND

There is a need for better understanding of how knee flexor strength influence patient-reported outcomes (PROs) after anterior cruciate ligament (ACL) reconstruction. Our aim was to investigate the relationship between the eccentric NordBord test and the seated concentric Biodex test with PROs, during the first year of rehabilitation after ACL reconstruction with hamstring tendon (HT) autograft.

METHODS

Patients with an index ACL reconstruction with an HT autograft participating in a rehabilitation registry were screened for inclusion. Outcomes of interest were the correlation between absolute (N/kg or Nm/kg) and relative (limb symmetry index) knee flexor strength measured in the NordBord and Biodex with the results of PROs. The significance level was set at p < 0.05 and Pearson's correlation coefficient was used.

RESULTS

137 patients were included (47% women) with a mean age of 24.8 ± 8.4 years. There were non-significant and weak correlations between relative strength for all PROs. Significant and weak correlations between absolute strength in the Biodex with the Knee Self-Efficacy Scale₁₈ (K-SES₁₈) present at 4 and 8 months, and for the ACL-Return to Sport after Injury scale (ACL-RSI) at 12 months was observed, accounting for 8.4-15.7% of the variance. Significant and weak correlations between absolute strength in the Nordbord with the Knee injury and Osteoarthritis Outcome Scale subscale Sports and Recreation at 4 months, the K-SES₁₈ present and the ACL-RSI at 8 months were observed, accounting for 9.4-14.4% of the variance.

CONCLUSION

Absolute knee flexor strength relative to bodyweight for both the Biodex and NordBord test appeared to have a stronger relationship with perceived knee function than relative knee flexor strength, although the observed correlations were weak.

Fear of reinjury following primary anterior cruciate ligament reconstruction: a systematic review

PURPOSE

This review aims to elucidate the most commonly reported method to quantify fear of reinjury or kinesiophobia and to identify key variables that influence the degree of kinesiophobia following primary anterior cruciate ligament reconstruction (ACLR).

METHODS

A systematic search across three databases (Pubmed, Ovid (MEDLINE), and EMBASE) was conducted from database inception to August 7th, 2022. The authors adhered to the PRISMA guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. Quality assessment of the included studies was conducted according to the Methodological Index for Non-Randomized Studies (MINORS) criteria.

RESULTS

Twenty-six studies satisfied the inclusion criteria and resulted in 2,213 total patients with a mean age of 27.6 years and a mean follow-up time of 36.7 months post-surgery. The mean MINORS score of the included studies was 11 out of 16 for non-comparative studies and 18 out of 24 for comparative studies. Eighty-eight percent of included studies used variations of the Tampa Scale of Kinesiophobia (TSK) to quantify kinesiophobia and 27.0% used Anterior Cruciate Ligament Return to Sport After Injury (ACL-RSI). The results of this study shows a common association between higher kinesiophobia and poor patient-reported functional status measured using International Knee Documentation Committee (IKDC) Scores, Activity of Daily Living (ADL), Quality of Life (QOL), and Sports/Recreation (S/R) subscales of Knee Osteoarthritis and Outcome Score (KOOS) and Lysholm scores. Postoperative symptoms and pain catastrophizing measured using the KOOS pain and symptom subscales and Pain Catastrophizing Score (PCS) also influenced the degree of kinesiophobia following ACLR. Patients with an increased injury to surgery time and being closer to the date of surgery postoperatively demonstrated higher levels of kinesiophobia. Less common variables included being a female patient, low preoperative and postoperative activity status and low self-efficacy.

CONCLUSION

The most common methods used to report kinesiophobia following primary ACLR were variations of the TSK scale followed by ACL-RSI. The most commonly reported factors influencing higher kinesiophobia in this patient population include lower patient-reported functional status, more severe postoperative symptoms such as pain, increased injury to surgery time, and being closer to the date of surgery postoperatively. Kinesiophobia following primary ACLR is a critical element affecting post-surgical outcomes, and screening should be implemented postoperatively to potentially treat in rehabilitation and recovery.

LEVEL OF EVIDENCE

IV.

Isometric Knee Muscle Strength and Patient-Reported Measures Five Years after Anterior Cruciate Ligament Reconstruction: Comparison of Single versus Dual Autograft Hamstring Tendon Harvesting

There is some controversy regarding the use of one or two hamstring tendons for anterior cruciate ligament reconstruction (ACLR). In this study, two cohorts of 22 male patients underwent an ACLR with hamstring tendon autografts. One cohort was reconstructed through an all-inside technique with the semitendinosus tendon (ST group) and the other with the semitendinosus and gracilis tendons (ST-G group). Anterior tibial translation (ATT), Lysholm, and IKDC scores were assessed preoperatively and five years postoperation. Additionally, isometric knee muscle strength was manually measured in both groups and in another cohort of 22 uninjured control male subjects five years after the operation. There were no significant differences in ATT and Lysholm scores between the operated groups. The IKDC score was lower in the ST-G group than in the ST group—9.57 (CI 14.89−4.25) (p < 0.001). No significant differences between injured and uninjured knees were detected in hamstring to quadriceps ratio strength and quadriceps limb symmetry index of the two operated groups, but the hamstring limb symmetry index was significantly lower in the ST-G group than in the ST and control groups. This study shows that using an ST-G autograft for ACLR yielded less flexor strength and worse results in some patient-reported outcome measures (PROM) than using an ST autograft five years after the operation. The observed results let us suggest that the use of one autograft hamstring tendon for ACLR is clinically preferable to the use of two hamstring tendons.

Rate of Torque Development in the Quadriceps after Anterior Cruciate Ligament Reconstruction with Hamstring Tendon Autografts in Young Female Athletes

This study aims to compare the limb symmetry index (LSI) of the rate of torque development (RTD) of the quadriceps with that of the peak torque after anterior cruciate ligament reconstruction (ACLR) using semitendinosus and gracilis tendon (STG) autografts and to investigate the associations of the LSI of torque parameters with patient-reported knee function. The participants included 23 female athletes after ACLR with STG grafts. Isometric quadriceps tests were performed using an isokinetic dynamometer. The peak torque, RTD₁₀₀ (0 to 100 ms) and RTD₂₀₀ (100 to 200 ms) were determined using torque-time curves. Comparisons of the LSI of torque parameters was performed by ANOVA. Univariate regression analysis was used to examine the relationship between the LSI of torque parameters and the patient-reported knee function. The LSIs of the peak torque and RTD₂₀₀ were significantly lower than that of the RTD₁₀₀ (p = 0.049, p = 0.039, respectively). Regression analysis showed that the LSI of the peak torque was associated with the patient-reported knee function (R² = 0.40, p = 0.001). It would be useful to evaluate the peak torque in young female athletes under the age of 18 and at 8-10 months after ACLR with STG grafts.

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.

Relationships between the seated single arm shot put test and Quick-DASH in patients being discharged from physical therapy

BACKGROUND

Research examining the relationship between patient reported outcomes (PRO) and upper extremity functional performance tests (UEFPT) in patients with shoulder pathology are limited.

OBJECTIVE

To assess the relationship between the seated single arm shot put test (SSASPT) and the PRO Quick-Disabilities of Arm, Shoulder, and Hand (DASH) in patients being discharged from physical therapy after shoulder injury or surgery.

METHODS

Six physical therapists who regularly use the SSASPT and DASH from six different clinical sites provided SSASPT scores and completed Quick-DASH forms on 75 patients being discharged from rehabilitation following shoulder injury or surgery. Patients were grouped according to whether the involved shoulder was the dominant (n = 43) or nondominant (n = 32) limb. Three separate simple linear regression models, whole cohort and two patient groups, were created to determine the magnitude of the relationships (standardized betas) and change (betas) between DASH scores and the SSASPT limb symmetry index (LSI).

RESULTS

Neither whole cohort nor two groups exhibited statistically significant (P > .05) relationships between LSI and Quick-DASH scores based upon the standardized betas (-0.197-0.038). Additionally, neither the standardized betas (z = 1.49, P = .135) nor betas (z = 1.28, P = .200) were statistically different between the two groups.

CONCLUSIONS

The current study revealed no association between SSASPT and the Quick-DASH at discharge from physical therapy following shoulder injury or surgery. Consequently, it may be important to perform a battery of tests that include both subjective PRO and objective UEFPT tests to obtain a comprehensive perspective of the patient's functional and perceived status.

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.

Recovery After ACL Reconstruction in Male Versus Female Adolescents: A Matched, Sex-Based Cohort Analysis of 543 Patients

Background:

Differences in postoperative recovery after anterior cruciate ligament reconstruction (ACLR) between men and women have been demonstrated in the adult population. Sex-based differences have been incompletely investigated in adolescents, which represent the subpopulation most affected by ACL injury.

Purpose/Hypothesis:

The purpose of this study was to compare the 6-month postoperative functional recovery after ACLR between adolescent boys and girls. It was hypothesized that significant differences in postoperative strength, dynamic balance, and functional hop test performance would be seen between the sexes.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Included in this study were athletes aged 12 to 19 years with closed or closing growth plates who underwent ACLR with hamstring autograft between May 2014 and May 2018 at a single institution. All athletes had undergone strength and functional testing between 5 and 8 months postoperatively. Exclusion criteria were previous knee surgery (contralateral or ipsilateral knee), concomitant injury/surgery other than meniscal tear/repair, allograft supplementation, and incomplete medical records. The limb symmetry index (LSI) for strength (measured with handheld dynamometer), as well as dynamic Y-balance and functional hop test performance, was compared between groups. To account for differences in physical characteristics between the sexes, 1-way between-group multivariate analysis of covariance was used to analyze the data.

Results:

Overall, 543 patients (211 boys, 332 girls) were included. There was no significant difference in age, body mass index, incidence of concomitant meniscal pathology, use of regional anesthesia, or time to functional testing between cohorts. Female athletes demonstrated a statistically significantly greater deficit in quadriceps strength LSI compared with male athletes (boys, +3.4%; girls, –2.3%; P = .011). Both male and female athletes demonstrated 33% hamstring strength deficits, with no statistically significant sex-based differences in dynamic balance or functional hop testing.

Conclusion:

Female athletes demonstrated greater quadriceps strength deficits than male athletes at 6 months after ACLR with hamstring autograft. Severe hamstring strength deficits persisted in both male and female patients at this time point. The correlation of such deficits to risk of ACL retear warrants continued study in the adolescent population and may support a delay in return to sports, which has been suggested in the more recent literature.

The Calculation, Thresholds and Reporting of Inter-Limb Strength Asymmetry: A Systematic Review

The prevalence of inter-limb strength differences is well documented in the literature however, there are inconsistencies related to measurement and reporting, and the normative values and effects associated with inter-limb asymmetry. Therefore, the aims of this systematic review were to: 1) assess the appropriateness of existing indices for the calculation of asymmetry, 2) interrogate the evidence basis for literature reported thresholds used to define asymmetry and 3) summarise normative levels of inter-limb strength asymmetry and their effects on injury and performance. To conduct this systematic review, scientific databases (PubMed, Scopus, SPORTDiscus and Web of Science) were searched and a total of 3,594 articles were retrieved and assessed for eligibility and article quality. The robustness of each identified asymmetry index was assessed, and the evidence-basis of the identified asymmetry thresholds was appraised retrospectively using the references provided. Fifty-three articles were included in this review. Only four of the twelve identified indices were unaffected by the limitations associated with selecting a reference limb. Eighteen articles applied a threshold to original research to identify "abnormal" asymmetry, fifteen of which utilised a threshold between 10-15%, yet this threshold was not always supported by appropriate evidence. Asymmetry scores ranged between and within populations from approximate symmetry to asymmetries larger than 15%. When reporting the effects of strength asymmetries, increased injury risk and detriments to performance were often associated with larger asymmetry, however the evidence was inconsistent. Limitations of asymmetry indices should be recognised, particularly those that require selection of a reference limb. Failure to reference the origin of the evidence for an asymmetry threshold reinforces doubt over the use of arbitrary thresholds, such as 10-15%. Therefore, an individual approach to defining asymmetry may be necessary to refine robust calculation methods and to establish appropriate thresholds across various samples and methodologies that enable appropriate conclusions to be drawn.

Satisfaction with playing pre-injury sports 1 year after anterior cruciate ligament reconstruction using a hamstring autograft

BACKGROUND

Few studies have examined patient satisfaction with playing pre-injury sports after anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to investigate patient satisfaction with playing pre-injury sport and identify factors associated with satisfaction.

METHODS

A total of 97 patients underwent unilateral ACL reconstruction using a hamstring autograft and returned to pre-injury sports 1 year after surgery. Patient satisfaction with playing pre-injury sport was assessed by a visual analog scale (VAS) and an ordinal four-grade scale. Problems related to the operated knee were also assessed. Knee muscle strength, single leg hop distance, knee laxity, subjective knee pain, and fear of movement/reinjury using Tampa Scale for Kinesiophobia-11 (TSK-11) were measured. Multivariate linear regression analysis was performed to determine the factors associated with patient satisfaction with playing pre-injury sport 1 year after surgery.

RESULTS

The average VAS score for patient satisfaction with playing pre-injury sports 1 year after surgery was 77.8 ± 20.2. Of the 97 patients, 87 patients (89.7%) answered "satisfied" or "mostly satisfied", whereas 51 patients (52.6%) had one or more problems. Multivariate linear regression analysis identified that the TSK-11 score was associated with patient satisfaction with playing a pre-injury sport 1 year after surgery.

CONCLUSION

Most of the patients who returned to pre-injury sports were satisfied with their outcomes. In contrast, approximately half of the patients had one or more problems after returning to play pre-injury sports. In particular, fear of movement/reinjury was significantly associated with patient satisfaction with playing pre-injury sport 1 year after surgery.

Knee flexor strength and symmetry vary by device, body position and angle of assessment following ACL reconstruction with hamstring grafts at long-term follow-up

PURPOSE

Persistent deficits in knee flexor strength following harvest of semitendinosus and gracilis for anterior cruciate ligament reconstruction are inconsistent in the literature. Variation in methodology, including measuring torque at higher knee flexion angles may partially explain these discrepant findings. The objective of this study was to determine whether positioning (seated vs supine), consideration of peak or joint-angle-specific torque or device (Isokinetic Dynamometer vs NordBord Hamstring Dynamometer) impact the magnitude of knee flexor strength differences between limbs.

METHODS

Participants (n = 31, 44.2 ± 10.7 years,) who were at 14 ± 4.4 years follow-up for unilateral ACL reconstruction with semitendinosus/gracilis grafts completed the ACL Quality of Life outcome and an assessment including isokinetic concentric knee extensor and flexor strength in seated and supine with peak torque and torque at 60° (T60) and 75° (T75) knee flexion measured, followed by an eccentric Nordic Hamstring Curl.

RESULTS

Isokinetic concentric knee flexor torque was reduced in supine relative to seated, on the reconstructed limb against the unaffected, and at higher degrees of knee flexion relative to peak torque (T60 and T75 against peak torque). Limb symmetry varied by methodology (F_(6,204) = 8.506, p = 0.001) with reduced symmetry in supine T75 against all measures (71.1 ± 16.5%, p < 0.05), supine T60 against seated peak torque (82.7 ± 14.2%, p < 0.05), and the NordBord was lower than seated peak torque that was not statistically significant (83.9 ± 12.8%, n.s.). Knee extensor peak (r² = 0.167 (F_(1,27) = 5.3, p = 0.03) and Nordic curl eccentric torque (r² = 0.267, F_(2,26) = 4.736, p = 0.02) were predictors of ACL-QoL score, although a combined model did not improve over Nordic torque alone.

CONCLUSION

Limb symmetry cannot be assumed in clinical practice across differing assessment methods for knee flexor strength as deficits are greatest in the supine position with torque measured at 75° knee flexion. Isokinetic knee extensor and eccentric knee flexor torque during the Nordic hamstring curl were predictors of ACL-QoL scoring and should be considered alongside patient-reported outcomes for patients following ACL reconstruction with hamstring grafts.

LEVEL OF EVIDENCE

Level IV.

The importance of biomechanical assessment after Return to Play in athletes with ACL-Reconstruction

BACKGROUND

Barriers to successful return to previous level of activity following Anterior Cruciate Ligament Reconstruction (ACLR) are multifactorial and recent research suggests that athletic performance deficits persist after completion of the rehabilitation course in a large percentage of patients.

RESEARCH QUESTION

Do technology-based biomechanical assessments reveal underneath differences in both recreational and competitive athletes in Return to Play after ACL-Reconstruction?

METHODS

Thirty soccer athletes (26.9 ± 5.7 years old, male) with ACL injury were surgically treated with all-inside technique and semitendinosus tendon autograft. Before 2 years from surgery, they were called back for clinical examination, self-reported psychological scores, and biomechanical outcomes (balance, strength, agility and velocity, and symmetry). Athletes were classified into recreational (n = 15) and competitive (n = 15) according to the self-reported Return to Play Level based on the TALS post-injury. Nonparametric statistical tests have been adopted for group comparisons in terms of age, concomitant presence of meniscus tear, injury on dominant leg, presence of knee laxity, presence of varus/valgus, body sides, and return to different levels of sports.

RESULTS

Competitive athletes showed better in terms of strength (45.3 ± 5.4 W kg^-1 vs 39.3 ± 3.4 W kg^-1, P ≤ 0.01) associated with good self-reported outcomes (TLKS, CRSQ) and low fear of reinjury (TSK). However, all the athletes had a functional deficit in at least one subtest, and a safe return to sports could not have been recommended. Our findings confirmed that demographics, physical function, and psychological factors were related to playing the preinjury level sport at mean 2 years after surgery, supporting the notion that returning to sport after surgery is multifactorial.

SIGNIFICANCE

A strict qualitative and quantitative assessment of athletes' status should be performed at different follow-ups after surgery to guarantee a safe and controlled RTP.

The influence of center line width during the crossover hop test

OBJECTIVES

To assess the influence of center line width on crossover hop for distance test (XHOP) performance.

DESIGN

Repeated measures.

SETTING

University laboratory.

PARTICIPANTS

33 physically active females without history of a ligamentous knee injury (age: 22.5 ± 2.3 years).

MAIN OUTCOME MEASURES

Hop distance was measured during four XHOP conditions with variations in center line width: 2.54 cm (narrow), 15 cm (standard), 12.5% of the participants' height (HT1), and 25% of the participants' height (HT2). A repeated measures ANOVA was used to evaluate differences in hop distance for XHOP condition (narrow, standard, HT1, and HT2).

RESULTS

Differences in hop distance were shown on XHOP condition (p < 0.001). Post hoc tests identified differences in hop distance between narrow and HT2 (p < 0.001, Effect size (ES) = 0.78), standard and HT2 (p < 0.001, ES = 0.57), and HT1 and HT2 (p < 0.001, ES = 0.58) conditions, respectively.

CONCLUSIONS

No differences in hop distance were identified between narrow and standard center line width XHOP conditions in healthy females. Decreased hop distance was shown when center line width was normalized to 25% of participant height in comparison to all other XHOP conditions, with medium effect sizes. This study highlights hop distance outcomes based on different XHOP center line widths, normalizing the XHOP according to height, and potential implications for frontal plane knee loading during the XHOP in healthy individuals.