Quadriceps Function, Knee Pain, and Self-Reported Outcomes in Patients With 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.

Acute anterior cruciate ligament rupture: can repair become an alternative to reconstruction: a meta-analysis of randomized controlled trials and cohort studies

PURPOSE

To perform a meta-analysis to compare clinical outcomes of anterior cruciate ligament (ACL) repair and ACL reconstruction for acute ACL rupture.

METHOD

We searched Pubmed, Embase, the Cochrane Library, and Web of Science databases to seek relevant studies. Clinical outcomes included failure rate, hardware removal rate, anteroposterior (AP) knee laxity, and patient-reported outcomes. In addition, subgroup analysis was carried out according to repair techniques, rupture locations, and study designs. Funnel plots were used to detect publication bias. All statistical analysis was performed using STATA (version 14.2, StataCorp).

RESULTS

A total of 10 articles were included in this study, comprising 5 randomized controlled trials (RCTs) and 5 cohort studies, involving a total of 549 patients. We found no statistical differences between the ACL repair and ACL reconstruction in the following outcomes: failure rate, AP knee laxity, International Knee Documentation Committee (IKDC) score, Lysholm score, Knee Injury and Osteoarthritis Outcome (KOOS) Score, and Tegner score. However, the ACL repair group had a higher hardware removal rate. Except for AP knee laxity results on different repair techniques, there was no statistical difference in other subgroup analyses.

CONCLUSION

Compared with ACL reconstruction, ACL repair shows similar results in clinical outcomes, and it is promising to be an effective alternative treatment for acute ACL rupture. Larger samples and higher-quality studies are needed to support our results and further explore the advantages of ACL repair in other aspects.

LEVEL OF EVIDENCE

Level III.

No Association Between Injury-Related Fear and Isokinetic Quadriceps Strength in Individuals With a History of Anterior Cruciate Ligament Reconstruction

CONTEXT

Injury-related fear and quadriceps strength are independently associated with secondary anterior cruciate ligament (ACL) injury risk. It is not known whether injury-related fear and quadriceps strength are associated, despite their individual predictive capabilities of secondary ACL injury. The purpose of this study was to examine the association between injury-related fear and quadriceps strength in individuals at least 1 year after ACL reconstruction (ACLR).

DESIGN

Cross-sectional study.

METHODS

Forty participants between the ages of 18 and 35 years at least 1 year post unilateral primary ACLR. Participants completed the Tampa Scale of Kinesiophobia-11 (TSK-11) and a standard isokinetic quadriceps strength assessment using the Biodex Isokinetic Dynamometer. Pearson Product-Moment correlations were used to examine the linear association between the TSK-11 scores and peak torque (in nanometers per kilogram) for each limb and between the TSK-11 scores and limb symmetry indices for each limb. Pearson Product-Moment correlation coefficients (r) were interpreted as very high (.90-1.00), high (.70-.90), moderate (.50-.70), low (.30-.50), and no correlation (.00-.30).

RESULTS

The average TSK-11 score was 18.2 (5.3), average ACLR peak quadriceps torque was 1.9 (0.50) N·m/kg, average contralateral peak quadriceps torque was 2.3 (0.48) N·m/kg, and average limb symmetry index was 85.3% (12.6%). There was no statistically significant correlation between the TSK-11 and peak quadriceps torque on the ACLR limb (r = .12, P = .46), the TSK-11 and contralateral limb (r = .29, P = .07), or the TSK-11 and limb symmetry index (r = -.18, P = .27).

CONCLUSIONS

There was no association between kinesiophobia and peak isokinetic quadriceps strength in individuals at least 1 year post-ACLR. Both factors, independently, have been shown to influence risk of secondary injury in patients after ACLR.

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/ .

Leaf spring exercise: A safe quadriceps strengthening exercise after anterior cruciate ligament reconstruction

BACKGROUND

Leg extensions should be avoided in the early stages after anterior cruciate ligament reconstruction because the force exerted by the quadriceps muscle leads to anterior tibial displacement. To allow for safe quadriceps training in the knee extension range during this period, we devised the leaf spring exercise, which involves placing subjects in the prone position with their knee slightly flexed and instructing them to perform maximum isometric quadriceps contractions while supporting the proximal region of the lower leg's anterior surface and immobilizing the femur's posterior surface to prevent lifting. The current study aimed to examine the safety of Leaf spring exercise by determining the femur-tibia relationship using ultrasound imaging.

METHODS

This controlled laboratory study included patients with unilateral anterior cruciate ligament-deficient knees (8 men and 8 women; age, 24.2 ± 8.3 years) who were instructed to perform Leaf spring exercise of both lower limbs. We measured the femur-tibia-step-off, which indicates the distance between the last point of the medial and lateral condyles of the femur and posterior margin of the tibial plateau, as a parameter to evaluate anterior tibial displacement via ultrasound diagnostic device. Further, peak torque of the quadriceps muscle was calculated using force measurement device.

FINDINGS

No difference in anterior tibial displacement and peak torque was observed between the uninjured and injured sides during Leaf spring exercise.

INTERPRETATION

Leaf spring exercise may add some strain on the reconstructed anterior cruciate ligament; hence, it can be considered a safe quadriceps exercise in the knee extension range.

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.

The Influence of Psychosocial Factors on Patients Undergoing Anterior Cruciate Ligament Reconstruction

CONTEXT

Anterior cruciate ligament (ACL) injuries greatly impact patients in terms of future performance, reduced physical activity and athletic participation, and overall economic burden. Decades of research have investigated how to improve ACL reconstruction (ACLR) outcomes. Recently, there has been growing interest to understand the effects of psychosocial factors on patient outcomes.

STUDY DESIGN

Clinical review.

EVIDENCE ACQUISITION

A search of the PubMed database was performed in March 2023. Articles were reviewed by at least 2 authors to determine relevance. We highlighted publications of the past 5 years while incorporating previous pertinent studies.

LEVEL OF EVIDENCE

Level 5.

RESULTS

There is no standardization of psychosocial factors regarding ACLR. As such, there is a lack of consensus regarding which psychosocial measures to use and when. There is a need for clarification of the complex relationship between psychosocial factors and physical function. Despite this, psychosocial factors have the potential to help predict patients who are more likely to return to sport: (1) desire/motivation to return; (2) lower levels of kinesiophobia; (3) higher levels of self-efficacy, confidence, and subjective knee function; (4) risk acceptance; and (5) social support. However, there are no standardized interventions to improve psychosocial factors after ACLR.

CONCLUSION

Psychosocial factors affect outcomes after ACLR. However, the interplay between psychosocial factors and physical function is complex. There is emerging evidence that testing and interventions may improve ACLR outcomes. There is a lack of standardized interventions to determine or improve psychosocial factors after ACLR. Further research is needed to identify psychosocial factors and to develop standardized interventions for clinicians to implement to improve clinical outcomes.

Preoperative psychological competitive ability has little relationship with subjective knee function and return to sports at 6 months postoperatively in patients with anterior cruciate ligament reconstruction

Objective

This prospective study aimed to investigate the relationship between preoperative psychological competitive ability and preoperative and 6 months postoperative subjective knee function in patients undergoing anterior cruciate ligament (ACL) reconstruction.

Methods

Eighty-four patients who underwent ACL reconstruction and had a Tegner Activity Scale score of 6 or more were included in this study. Preoperatively, all patients were administered the Diagnostic Inventory of Psychological Competitive Ability for Athletes (DIPCA.3) for psychological competitive ability assessment and the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form for subjective knee function assessment. The IKDC subjective score was re-evaluated 6 months postoperatively. We evaluated the associations of volition for competition, mental stability and concentration, confidence, strategic ability, and cooperation (DIPCA.3 factors) with the IKDC subjective score preoperatively and 6 months postoperatively. Furthermore, patients were classified into two groups according to whether they could return to participate in the entire practice and compared the DIPCA.3 total score and IKDC subjective score.

Results

The DIPCA.3 confidence score negatively correlated with the preoperative IKDC subjective score (β = -0.34, p = 0.04). However, there was no association between the DIPCA.3 score for all variables and IKDC subjective score at 6 months after ACL reconstruction. Moreover, the DIPCA.3 total score was not related to return to participate in the entire practice 6 months after ACL reconstruction.

Conclusion

Psychological competitive ability is not associated with a return to participate in the entire practice, and a low preoperative IKDC subjective score should not be viewed too negatively.

Clinical Utility of Ultrasound Imaging for Measuring Anterior Thigh Thickness after Anterior Cruciate Ligament Injury in an Individual Patient to Assess Postsurgery Outcome

The present study investigated the clinical utility of ultrasound imaging (USI) for assessing changes in an individual's quadriceps muscle and subcutaneous fat (SF) thickness of the anterior thigh and their relative proportions. A patient was studied prior to and after anterior cruciate ligament reconstruction (ACLR) surgery and during rehabilitation. This case study involved an 18-year-old female recreational athlete with a complete tear of the anterior cruciate ligament (ACL). Tissue thickness (SF and quadriceps muscle) was measured from transverse USI of the anterior thigh before surgery, at weekly intervals during 12 weeks of postsurgery, and then every 2 weeks for the following 12 weeks (total of 21 measurement sets). Statistically significant differences presurgery to postrehabilitation were found for muscle thickness (p = 0.04) and SF tissue thickness (p = 0.04) measurements. There was no difference in muscle to fat ratio (p = 0.08). Changes in measurements greater than the reported minimal detectable change (MDC) demonstrate the sensitivity of the USI technique as an objective tool to assess clinically useful changes in an individual's anterior thigh muscle thickness post-ACLR surgery and during rehabilitation.

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.

Quadriceps torque complexity before and after anterior cruciate ligament reconstruction

OBJECTIVES

The purpose of this project was to longitudinally examine quadriceps torque complexity in a group of individuals who tore their ACL and underwent ACL reconstruction.

DESIGN

Cohort analysis.

METHODS

Thirty-four individuals completed maximal effort bilateral isometric strength testing after ACL injury but pre-surgery, five months' post-surgery (mid-point of rehabilitation), and when cleared to return to activity. Sample entropy, a nonlinear analysis of quadriceps torque control (complexity), was calculated from maximal isometric contractions. Two 3 × 2 repeated measures analysis of variance were used to examine changes over time and between limbs for quadriceps torque complexity and peak torque.

RESULTS

Quadriceps peak torque was lower in the involved limb when compared to the uninvolved limb at every time point (p < 0.001). Peak torque of the involved limb was decreased at mid-point of rehabilitation compared to before surgery (p = 0.023) and at mid-point compared to return to activity (p = 0.041). Quadriceps sample entropy was higher in the involved limb compared to the uninvolved limb at the mid-point of rehabilitation (p < 0.001) and return to activity (p < 0.001), indicating greater complexity. The involved limb also demonstrated increased torque sample entropy from pre-surgery to mid-point of rehabilitation (p = 0.023), but not from pre-surgery to return to activity (p = 0.169) or from mid-point to return to activity (p = 0.541).

CONCLUSIONS

Not only does quadriceps strength decline with ACL reconstruction, but quality of the quadriceps muscle contraction is also compromised. Increased torque complexity experienced in the ACL limb after reconstruction may contribute to impaired physical function in individuals following ACL reconstruction.

Association of Psychological Readiness to Return to Sports With Subjective Level of Return at 12 Months After ACL Reconstruction

Background

Return-to-sports (RTS) rates after anterior cruciate ligament (ACL) reconstruction (ACLR) differ according to the level at which patients return. It is unclear whether the level of RTS is affected by psychological readiness to return.

Purpose

To examine the association between psychological readiness to RTS and subjective RTS level 12 months after ACLR.

Study Design

Case-control study; Level of evidence, 3.

Methods

A total of 47 patients who underwent unilateral primary ACLR surgery were enrolled. Assessments at 6 and 12 months postoperatively consisted of knee strength testing (isokinetic quadriceps and hamstring strength), the International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC-SKF), and the Anterior Cruciate Ligament-Return to Sport after Injury (ACL-RSI) scale to measure psychological readiness to RTS. Patients were assigned to 1 of 3 subgroups based on their subjective assessment of RTS level at 12 months postoperatively: RTS at or above preinjury level (RTS≥Pre; n = 19), RTS below preinjury level (RTS

Results

Significant differences were found among the RTS≥Pre, RTS

Conclusion

The ACL-RSI score was significantly different among the study groups, and the ACL-RSI score at 12 months postoperatively and younger age were associated with RTS at or above preinjury level.

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Key Words

• ACL-RSI
• knee strength
• patient-reported knee function
• performance

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MESH Headings Collapse

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Affiliation(s)

Makoto Suzuki Faculty of Health Sciences, Hokkaido University, Sapporo, Japan Department of Rehabilitation, Hokushin Orthopaedic Hospital, Sapporo, Japan
Tomoya Ishida Faculty of Health Sciences, Hokkaido University, Sapporo, Japan Department of Rehabilitation, Hokushin Orthopaedic Hospital, Sapporo, Japan
Hisashi Matsumoto Department of Rehabilitation, Hokushin Orthopaedic Hospital, Sapporo, Japan
Satoru Kaneko Department of Orthopaedic Surgery, Hokushin Orthopaedic Hospital, Sapporo, Japan
Chiharu Inoue Department of Orthopaedic Surgery, Hokushin Orthopaedic Hospital, Sapporo, Japan
Yoshimitsu Aoki Department of Orthopaedic Surgery, Hokushin Orthopaedic Hospital, Sapporo, Japan
Harukazu Tohyama Faculty of Health Sciences, Hokkaido University, Sapporo, Japan
Mina Samukawa Faculty of Health Sciences, Hokkaido University, Sapporo, Japan

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Quadriceps Strength and Knee-Related Symptom State 6 Months After Anterior Cruciate Ligament Reconstruction

CONTEXT

Isometric quadriceps strength metrics and patient-reported outcomes are commonly used in return-to-sport assessments in those with anterior cruciate ligament reconstruction (ACLR). Patients may experience clinical knee-related symptoms aggravating enough to seek additional medical care after ACLR. In addition to seeking additional medical care, these patient-reported clinical knee-related symptoms may also influence function after ACLR. However, whether an association exists between these common quadriceps metrics and the patient-reported clinical knee-related symptom state is unknown.

OBJECTIVE

To determine if meeting isometric quadriceps strength and symmetry criteria is associated with acceptable clinical knee-related symptoms at 5 to 7 months post-ACLR.

DESIGN

Cross-sectional study.

SETTING

Laboratories.

PATIENTS OR OTHER PARTICIPANTS

We classified individuals at 5 to 7 months post-ACLR based on their isometric ACLR and uninvolved-limb quadriceps strength or quadriceps strength symmetry. We also dichotomized participants based on the Englund et al criteria for unacceptable clinical knee-related symptoms.

MAIN OUTCOME MEASURE(S)

Quadriceps strength variables were compared between groups using analysis of covariance, and the relative risk of a participant in each quadriceps strength group reporting acceptable clinical knee-related symptoms was determined using binary logistic regression.

RESULTS

A total of 173 individuals participated. The isometric quadriceps strength and limb symmetry index were different (P < .001) between quadriceps strength groups. Those categorized as both strong and symmetric had a 1.28 (95% CI = 0.94, 1.74) and individuals categorized as symmetric only had a 1.29 (95% CI = 0.97, 1.73) times greater relative risk of reporting acceptable clinical knee-related symptoms compared with the neither strong nor symmetric group.

CONCLUSIONS

The majority of individuals (85%) recovering from ACLR failed to meet either the clinical quadriceps strength or symmetry criteria at 5 to 7 months post-ACLR. Quadriceps strength and quadriceps strength symmetry are clinically important but may not be primary determinants of the clinical knee-related symptom state within the first 6 months post-ACLR.

Patient-Reported Measures Associated with the Return to Pre-Injury Levels of Sport 2 Years after Anterior Cruciate Ligament Reconstruction

The International Knee Documentation Committee Subjective Knee Form (IKDC2000) and the Knee Injury and Osteoarthritis Outcome Score (KOOS) are knee-specific measures. However, their association with a return to sports after anterior cruciate ligament reconstruction (ACLR) is unknown. This study aimed to investigate the association between the IKDC2000 and the KOOS subscales and the return to the same pre-injury level of sport two years after ACLR. Forty athletes that were two years post-ACLR participated in this study. Athletes provided demographic information, filled out the IKDC2000 and KOOS subscales, and indicated whether they returned to any sport and whether they returned to the same pre-injury level (same duration, intensity, and frequency). In this study, 29 (72.5%) athletes returned to play any sport and eight (20%) returned to the same pre-injury level. The IKDC2000 (r: 0.306, p = 0.041) and KOOS quality of life (KOOS-QOL) (r: 0.294, p = 0.046) significantly correlated with the return to any sport, but it was age (r: -0.364, p = 0.021), BMI (r: -0.342, p = 0.031), IKDC2000 (r: 0.447, p = 0.002), KOOS-pain (r: 0.317, p = 0.046), KOOS sport and recreation function (KOOS-sport/rec)(r: 0.371, p = 0.018), and KOOS QOL (r: 0.580, p > 0.001) that significantly correlated with a return to the same pre-injury level. High KOOS-QOL and IKDC2000 scores were associated with returning to any sport, and high KOOS-pain, KOOS-sport/rec, KOOS-QOL, and IKDC2000 scores were all associated with returning to the same pre-injury level of sport.

Mobile health-based home rehabilitation education improving early outcomes after anterior cruciate ligament reconstruction: A randomized controlled clinical trial

Objective

This study aimed to assess changes in joint range of motion (ROM) and knee joint function between patients who received the mobile health-based intervention and those who received regular care at 2 and 6 weeks after anterior cruciate ligament (ACL) reconstruction to provide better interventions in the future.

Methods

Patients who underwent ACL reconstruction were randomized into the experimental [Mobile health-based intervention (MHI); n = 62] and control (CON) groups (n = 63). The CON group underwent home-based rehabilitation exercise following the paper rehabilitation schedule, while the intervention group received additional mobile health-based education at weeks 1-6 after surgery. ROM, thigh circumference difference, and flexion pain were the primary outcomes. The secondary outcomes were the international knee documentation committee knee evaluation form (IKDC) scores and rehabilitation compliance scores. All the outcomes were measured 1 day before surgery as references and at 2 and 6 weeks after surgery.

Results

There was no statistical difference in the patients' ROM, thigh circumference difference, and VAS scores at the 2-week follow-up. At the 6-week follow-up, the ROM of the affected leg was (118.1 ± 20.5)° in the CON group and (126.6 ± 20.5)° in the MHI group, and the difference was statistically significant (P = 0.011). The difference in thigh circumference was 3.0 (2.0, 3.5) cm in the CON group and 2.5 (1.0, 3.0) cm in the MHI group. The difference was statistically significant (P < 0.001). The VAS score in the CON group was 3.0 (2.0, 4.0), and the MHI group was 2.5 (1.0, 3.0). The difference was statistically significant (P < 0.05). At the 6-week follow-up, the compliance score of patients in the MHI group was significantly higher than that in the CON group (P = 0.047, β = 2.243, 95%CI: 0.026-4.459). There is no statistically significant difference in IKDC scores.

Conclusion

Mobile health-based intervention positively affected patients undergoing ACL reconstruction surgery, particularly in improving the clinical outcome indicators of the knee joint.

Correlations of strength, proprioception, and tactile sensation to return-to-sports readiness among patients with anterior cruciate ligament reconstruction

Objectives: Anterior cruciate ligament reconstruction (ACLR) is the most common surgery for anterior cruciate ligament (ACL) injuries, and the relationships between patients' return to sports (RTS) readiness and different physical functions are inconclusive among patients with ACLR. This study aimed to investigate the correlations of strength, proprioception, and tactile sensation to the RTS readiness among patients with ACLR. Methods: Forty-two participants who received ACLR for at least 6 months were enrolled in this study. Their strength, proprioception, and tactile sensation were tested, and their RTS readiness was measured with the Knee Santy Athletic Return to Sports (K-STARTS) test, which consists of a psychological scale [Anterior Cruciate Ligament Return to Sports after Injury scale (ACL-RSI)] and seven functional tests. Partial correlations were used to determine their correlations while controlling for covariates (age, height, weight, and postoperative duration), and factor analysis and multivariable linear regressions were used to determine the degrees of correlation. Results: Knee extension strength was moderately correlated with K-STARTS total, ACL-RSI, and functional scores. Knee flexion strength, knee flexion and extension proprioception, and tactile sensation at the fifth metatarsal were moderately correlated with K-STARTS total and functional scores. Strength has higher levels of correlation with functional scores than proprioception. Conclusion: Rehabilitation to promote muscle strength, proprioception and tactile sensation should be performed among patients with ACLR, muscle strength has the highest priority, followed by proprioception, with tactile sensation making the least contribution.

Isometric Knee Strength is Greater in Individuals Who Score Higher on Psychological Readiness to Return to Sport After Primary Anterior Cruciate Ligament Reconstruction

Background

Anterior cruciate ligament (ACL) injury is extremely common among athletes. Rate of second ACL injury due to surgical graft rupture or contralateral limb ACL injury is approximately 15-32%. Psychological readiness to return to sport (RTS) may be an important predictor of successful RTS outcomes. Psychological readiness can be quantified using the ACL Return to Sport after Injury (ACL-RSI) questionnaire, with higher scores demonstrating greater psychological readiness.

Purpose

The purpose of this study was to investigate differences in functional performance and psychological readiness to return to sport among athletes who have undergone primary ACL reconstruction (ACLR).

Study Design

Descriptive cohort study.

Methods

Eighteen athletes who had undergone primary ACLR were tested at time of RTS clearance. The cohort was divided into two groups, high score (HS) and low score (LS), based on median ACL-RSI score, and performance on static and dynamic postural stability testing, lower extremity isokinetic and isometric strength testing, and single leg hop testing was compared between the groups using an independent samples t-test.

Results

The median ACL-RSI score was 74.17. The average ACL-RSI score was 83.1±6.2 for the HS group and 61.8±8.0 for the LS group. High scorers on the ACL-RSI performed significantly better on isometric knee flexion as measured via handheld dynamometry (22.61% ±6.01 vs. 12.12% ±4.88, p=0.001) than the low score group.

Conclusion

The findings suggest that increased knee flexion strength may be important for psychological readiness to RTS after primary ACLR. Further research is indicated to explore this relationship, however, a continued emphasis on improving hamstring strength may be appropriate during rehabilitation following ACLR to positively impact psychological readiness for RTS.

Level of Evidence

III.

Knee Strength Assessment and Clinical Evaluation Could Predict Return to Running after Anterior Cruciate Ligament Reconstruction Using Patellar Tendon Procedure

BACKGROUND AND OBJECTIVES

Muscle knee strength is a major parameter that allows return to running. Isokinetic strength parameters may predict return to running 4 months after ACLR using the bone-patellar-tendon-bone procedure.

MATERIALS AND METHODS

The isokinetic knee strength of 216 patients (24.5 ± 5 years) was measured 4 months after surgery, and progressive return to running was allowed. The effectiveness of return to running was reported at 6 months. Return to running prediction was established using multivariate logistic regression. Predictive parameters were presented with a ROC curve area to define the best cut-off, with sensibility (Se) and specificity (Sp).

RESULTS

A model was established, including the limb symmetry index (LSI), and 103 patients (47.6%) were able to run between the fourth and the sixth month after surgery. These patients presented significantly fewer knee complications, a better Lysholm score, a better Quadriceps and Hamstring LSI and better quadriceps strength reported for body weight on the operated limb. The best model was established including the Quadriceps and Hamstring LSI at 60°/s and the Lysholm score. The cut-off for Quadriceps LSI was 60% (ROC curve area: 0.847; Se: 77.5%; Sp: 77%), for Hamstring LSI 90% (ROC curve area: 0.716; Se: 65.7%; Sp: 60.2%) and for Lyshom score 97 points (ROC curve area: 0.691; Se: 65%; Sp: 66%).

CONCLUSION

Four months after ACLR using a bone-patellar-tendon-bone procedure, the Quadriceps and Hamstring LSI associated to the Lysholm score could help make the decision to allow return to running.

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.

Relevant Strength Parameters to Allow Return to Running after Primary Anterior Cruciate Ligament Reconstruction with Hamstring Tendon Autograft

After anterior cruciate ligament reconstruction (ACLR), a progressive process is followed from rehabilitation to the return to sport including a crucial step known as the return to running. Return to running (RTR) can be predicted by an isokinetic knee strength assessment at 4 months post-surgery. All patients who had primarily undergone ACLR with a hamstring autograft procedure between 2010 and 2020 were included in this study. Four months after surgery, patients were evaluated using an isokinetic knee strength test. Patients were monitored until the 6th month post-surgery to see if they had returned to running. Comparisons were carried out between the two groups—the RTR and the no-RTR. A multivariate logistic regression analysis was used to predict the RTR status from explicative parameters. Receiver Operating Characteristic (ROC) curves were established to identify cutoffs with their characteristics. A total of 413 patients were included and 63.2% returned to running at 4 months post-surgery. The mean Lysholm score, knee complication rate, and isokinetic parameters were statistically different between both groups. Using a multivariate logistic regression model and ROC curves, the best isokinetic parameter to assist with the decision to allow an RTR was the quadriceps limb symmetry index at 60°/s with a cutoff of 65%. The hamstring LSI at 180°/s could be added (cutoff of 80%) to slightly increase the prediction of an RTR. Quadriceps strength normalized to body weight at 60°/s is a useful parameter (cutoff: 1.60 Nm/kg) but measurements on both sides are necessary. Isokinetic parameters are objective parameters to allow a return to running at 4 months after ACLR with a hamstring procedure.

Cross-sectional study on relationships between physical function and psychological readiness to return to sport after anterior cruciate ligament reconstruction

BACKGROUND

Information about specific factors of physical function that contribute to psychological readiness is needed to plan rehabilitation for a return to sports. The purpose of this study was to identify specific physical functions related to the psychological readiness of patients aiming to return to sports 6 months after reconstruction. We hypothesized that the knee strength is a factor related to the Anterior Cruciate Ligament-Return to Sport after Injury scale (ACL-RSI) cutoff score for a return to sports.

METHODS

This was a cross-sectional study. Fifty-four patients who had undergone primary reconstruction using hamstring tendon participated in this study. Psychological readiness was measured using the ACL-RSI in patients at 6 months after reconstruction. To identify specific physical functions related to the ACL-RSI score, participants were divided into groups with ACL-RSI scores of ≥ 60 or < 60. Non-paired t-tests or the Mann-Whitney test were performed to analyze group differences in objective variables in physical function: (1) knee strength in both legs; (2) leg anterior reach distance on both sides; and (3) single-leg hop (SLH) distances in three directions for both legs.

RESULTS

Significant differences between groups were identified in knee flexion strength (60°/s) for the uninvolved limb, hamstring-to-quadriceps ratio (60°/s) for the uninvolved limb, knee flexion strength (180°/s) for the involved limb, limb symmetry index (LSI) of leg anterior reach distance, the ratio of the distance to the height of the patient and LSI of SLH distances in lateral and medial directions.

CONCLUSION

This study revealed that at 6 months after reconstruction, increased knee flexion strength (ratio of peak torque measured to body mass of the patient), hamstring-to-quadriceps ratio, leg anterior reach distance LSI, and lateral and medial SLH appear important to exceed the ACL-RSI cutoff for a return to sports. The present results may be useful for planning post-operative rehabilitation for long-term return to sports after reconstruction.

Association Between Meeting Return-to-Sport Criteria and Psychological Readiness to Return to Sport After Anterior Cruciate Ligament Reconstruction

Background:

The relationship between meeting return-to-sport criteria and psychological readiness after anterior cruciate ligament (ACL) reconstruction is unknown.

Purposes:

To examine (1) whether patients who met 1 of the criteria for return to sport had higher psychological readiness than those who did not meet any of the criteria and (2) if those who met more criteria had higher psychological readiness.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

This study included 144 patients who underwent unilateral ACL reconstruction. All patients had regularly participated in some sport activities before an ACL rupture. At 12 months postoperatively, each patient completed 3 knee function tests (isokinetic quadriceps strength, isokinetic hamstring strength, and single-leg hop distance) and 2 self-reported measures (International Knee Documentation Committee [IKDC] 2000 subjective form and ACL–Return to Sport after Injury [ACL-RSI] scale); the ACL-RSI scale was used to measure psychological readiness to return to sport. The 4 criteria for return to sport were a limb symmetry index (LSI) ≥90% for each of the 3 function tests in addition to an IKDC score ≥90. Multivariate regression analysis was used to determine the association between meeting the individual criteria and the ACL-RSI score. In addition, the patients were divided into 5 groups according to the number of criteria met, and the Kruskal-Wallis and Steel-Dwass tests were used to compare the ACL-RSI scores among the groups.

Results:

Overall, 23 patients (16.0%) met none of the criteria for return to sport, 27 (18.7%) met 1 of the criteria, 34 (23.6%) met 2 criteria, 35 (24.3%) met 3 criteria, and 25 (17.4%) met all 4 criteria. Meeting the criteria for the hamstring strength LSI (P = .002), single-leg hop distance LSI (P = .004), and IKDC subjective score (P < .001) was each associated with higher ACL-RSI scores. Significant differences in ACL-RSI scores were found between patients who met none versus 2, 3, and 4 of the return-to-sport criteria (P < .001 for all) and between patients who met 1 versus 4 criteria (P < .001).

Conclusion:

Meeting return-to-sport criteria was positively associated with psychological readiness, and the patients who met multiple criteria had higher psychological readiness.

Effect of Low-Load Blood Flow Restriction Training After Anterior Cruciate Ligament Reconstruction: A Systematic Review

Background

Quadriceps strength and mass deficits are common after anterior cruciate ligament (ACL) reconstruction. Postoperatively, heavy load resistance training can have detrimental effects on knee joint pain and ACL graft laxity. Therefore, low-load blood flow restriction (LL-BFR) training has been suggested as an alternative to traditional strength rehabilitation.

Purpose

The present systematic review aimed to investigate the effect of LL-BFR training on quadriceps strength, quadriceps mass, knee joint pain, and ACL graft laxity after ACL reconstruction compared to non-BFR training.

Study design

Systematic review.

Methods

A systematic literature search of PubMed, EMBASE.com, Cochrane Library/Wiley, CINAHL/Ebsco and Web of Science/Clarivate Analytics was performed on 19 February 2021. Studies were included if they compared LL-BFR and non-BFR training after ACL reconstruction with pre- and post-intervention quadriceps strength, quadriceps mass, knee joint pain or ACL graft laxity measurement. Systematic reviews, editorials, case reports and studies not published in a scientific peer reviewed journal were excluded. The risk of bias of randomized studies was assessed with the use of the Cochrane Risk of Bias Tool.

Results

A total of six randomized controlled trials were included. Random sequence generation and allocation concealment was defined as high risk in two of the six studies. In all studies blinding of participants and personnel was unclear or could not be performed. The included studies used different LL-BFR and non-BFR protocols with heterogeneous outcome measurements. Therefore, a qualitative analysis was performed. Two of the six studies assessed quadriceps strength and demonstrated significant greater quadriceps strength after LL-BFR compared to non-BFR training. Quadriceps mass was evaluated in four studies. Two studies observed significant greater quadriceps mass after LL-BFR compared to non-BFR training, while two studies observed no significant difference in quadriceps mass. Knee joint pain was assessed in three studies with significantly less knee joint pain after LL-BFR compared to non-BFR training. Two studies evaluated ACL graft laxity and observed no significant difference in ACL graft laxity between LL-BFR and non-BFR training.

Conclusion

The results of this systematic review indicate that LL-BFR training after ACL reconstruction may be beneficial on quadriceps strength, quadriceps mass, and knee joint pain compared to non-BFR training with non-detrimental effects on ACL graft laxity. However, more randomized controlled trials with standardized intervention protocols and outcome measurements are needed to add evidence on the clinical value of LL-BFR training.

Level of evidence

2a.

Arthrogenic Muscle Inhibition Following Anterior Cruciate Ligament Injury

Arthrogenic muscle inhibition (AMI) is a common impairment in individuals who sustain an anterior cruciate ligament (ACL) injury. The AMI causes decreased muscle activation, which impairs muscle strength, leading to aberrant movement biomechanics. The AMI is often resistant to traditional rehabilitation techniques, which leads to persistent neuromuscular deficits following ACL reconstruction. To better treat AMI following ACL injury and ACL reconstruction, it is important to understand the specific neural pathways involved in AMI pathogenesis, as well as the changes in muscle function that may impact movement biomechanics and long-term structural alterations to joint tissue. Overall, AMI is a critical factor that limits optimal rehabilitation outcomes following ACL injury and ACL reconstruction. This review discusses the current understanding of the: (1) neural pathways involved in the AMI pathogenesis following ACL injury; (2) consequence of AMI on muscle function, joint biomechanics, and patient function; and (3) development of posttraumatic osteoarthritis. Finally, the authors review the evidence for interventions specifically used to target AMI following ACL injury.

Self-Reported Symptoms of Depression and Anxiety After ACL Injury: A Systematic Review

Background:

Depression and anxiety symptoms can occur in patients following an anterior cruciate ligament (ACL) injury, and the presence of these symptoms has been associated with poorer self-reported knee function in this type of injury.

Purpose:

To investigate the prevalence and severity of self-reported symptoms of depression and anxiety following an ACL injury.

Study Design

Systematic review; Level of evidence, 4.

Methods:

PubMed, Cochrane Library, Embase, PsycINFO, AMED, and PEDro databases were searched using a combination of keywords relating to ACL, depression, anxiety, and their synonyms. Inclusion criteria were clinical studies written in English that reported on patients with an injured and/or reconstructed ACL and assessed symptoms of depression and/or anxiety. Data extraction was performed independently by 2 authors. Data synthesis was performed using an emergent synthesis approach. The quality of the included studies was assessed using the methodological index for non-randomized studies or the Mixed-Methods Appraisal Tool. Certainty of evidence was determined using the Grading of Recommendations Assessment, Development and Evaluation.

Results:

After abstract screening, 37 studies were assessed in full text, of which 16 were included. The studies comprised 682 patients (417 male [61%]). The depression symptoms appeared to be more severe in elite athletes compared with recreational athletes. Symptoms decreased over time from moment of ACL reconstruction to up to 2 years postoperatively. The prevalence of self-reported symptoms of anxiety after an ACL injury was reported in 1 study (2%). There were no differences in anxiety symptoms between professional and amateur athletes or between adolescents and adults. The overall quality of the studies was low or very low.

Conclusion:

Patients who sustain an ACL injury can suffer from symptoms of depression, especially during the first 6 weeks after ACL reconstruction. Depressive symptoms are more common among professional versus nonprofessional athletes. Levels of anxiety symptoms were not above the cutoffs for a diagnosis of anxiety after an ACL injury.

Estimates of voluntary activation in individuals with anterior cruciate ligament reconstruction: Effects of type of stimulator, number of stimuli, and quantification technique

BACKGROUND

Accurate quantification of voluntary activation is important for understanding the extent of quadriceps dysfunction in individuals with anterior cruciate ligament reconstruction (ACLR). Voluntary activation has been quantified using both percent activation derived from the interpolated twitch technique and central activation ratio (CAR) derived from the burst superimposition technique, as well as by using different types of electrical stimulators and pulse train conditions. However, it is unclear how these parameters affect voluntary activation estimates in individuals with ACLR. This study was performed to fill this important knowledge gap in the anterior cruciate ligament literature.

METHODS

Quadriceps strength and voluntary activation were examined in 18 ACLR participants (12 quadriceps/patellar tendon graft, 6 hamstring tendon graft; time since ACLR: 1.06 ± 0.82 years, mean ±  SD) at 90° of knee flexion using 2 stimulators (Digitimer and Grass) and pulse train conditions (3-pulse and 10-pulse). Voluntary activation was quantified by calculating both CAR and percent activation.

RESULTS

Results indicated that voluntary activation was significantly overestimated by CAR when compared with percent activation (p < 0.001). Voluntary activation estimates were not affected by pulse train conditions when using percent activation; however, 3-pulse stimuli resulted in greater overestimation than 10-pulse stimuli when using CAR (p = 0.003). Voluntary activation did not differ between stimulators (p > 0.05); however, the Digitimer evoked greater torque at rest than the Grass (p < 0.001).

CONCLUSION

These results indicate that percent activation derived from the interpolated twitch technique provides superior estimates of voluntary activation than CAR derived from burst superimposition and is less affected by pulse train conditions or stimulators in individuals with ACLR.

The Neuromatrix Theory of Pain and Transactional Theory of Stress and Coping: Improving Understanding of Pain Catastrophizing in Individuals With ACL Reconstruction and Knee Osteoarthritis

Individuals with anterior cruciate ligament reconstruction and early knee osteoarthritis symptoms commonly exhibit psychological impairments, such as pain catastrophizing. Pain catastrophizing is a negative cognitive–affective response to anticipated or actual pain and has been linked to greater pain intensity and decreased function in this population. However, an examination of the neuromatrix theory of pain and the transactional theory of stress and coping may help to explain the development and consequences of pain catastrophizing in individuals with anterior cruciate ligament reconstruction and early knee osteoarthritis symptoms. Exploration of these theoretical models will help clinicians better understand the impact of pain catastrophizing on post-injury outcomes, as well as help to identify intervention strategies to address maladaptive psychological responses and improve outcomes for individuals with anterior cruciate ligament reconstruction and early knee osteoarthritis symptoms.

Psychosocial factors 3-months after anterior cruciate ligament reconstruction predict 6-month subjective and objective knee outcomes

The objective of the study was to determine if psychological readiness for sport and knee self-efficacy assessed early (3 months) after anterior cruciate ligament reconstruction (ACLR) are predictive of self-reported functional outcomes, quadriceps strength, and knee mechanics while running at the time of return to sport training (6 months). Thirty athletes with unilateral ACLR completed the ACL Return to Sport after Injury (ACL-RSI) and Knee Self-Efficacy Scale (K-SES) 3 months after ACLR and completed self-reported functional outcomes, isometric quadriceps strength testing, and three-dimensional running gait analysis 6 months after ACLR. The 3-month ACL-RSI significantly correlated with the 6-month International Knee Documentation Committee (IKDC; r = 0.565, p = 0.001), Knee Injury and Osteoarthritis Outcome Score (KOOS) sport/recreational activities (KOOS_Sport ; r = 0.548, p = 0.002) and quality of life (KOOS_QoL ; r = 0.431, p = 0.017), and quadriceps strength (r = 0.528, p = 0.003). The 3-month K-SES significantly correlated with the 6-month IKDC (r = 0.528, p = 0.003), KOOS_Sport (r = 0.430, p = 0.018), KOOS_QoL (r = 0.411, p = 0.024), quadriceps strength (r = 0.465, p = 0.010), and knee flexion excursion (r = 0.472, p = 0.008). With multivariate modeling, both the ACL-RSI and K-SES were predictive of the IKDC (R²  = 0.411; p = 0.001). Only the ACL-RSI was predictive of the KOOS_Sport (R²  = 0.300; p = 0.002), KOOS_QoL (R²  = 0.186; p = 0.017), and quadriceps strength (R²  = 0.279; p = 0.003), whereas only the K-SES was predictive of knee flexion excursion (R²  = 0.173; p = 0.022). Athletes with greater psychological readiness for sport and knee self-efficacy at 3 months demonstrated higher scores on self-reported functional outcomes, greater quadriceps strength, and greater knee flexion excursion at 6 months after ACLR. This study indicates that psychosocial measures may be important to include into early post-surgical evaluations to help guide and facilitate interventions to restore subjective and objective knee function.

Confidence, ability to meet return to sport criteria, and second ACL injury risk associations after ACL-reconstruction

This study tested the hypotheses that participants with high knee-related confidence at the time of return to sport (RTS) after anterior cruciate ligament (ACL) reconstruction (ACLR) would have a greater likelihood of meeting RTS criteria and would have a higher likelihood of second ACL injury. Participants completed RTS testing when cleared to RTS. Success was defined as an IKDC score more than or equal to 90 and all limb symmetry index (LSI) scores more than or equal to 90%. Confidence groups were created based on response to the KOOS Quality of Life subscale. Incidence of second ACL injury was tracked for 24 months after RTS. Associations among confidence, success in meeting RTS criteria, and second ACL injury were evaluated. At RTS, 37.7% were classified with high knee-related confidence, 26.4% met RTS criteria and 22.0% sustained a second ACL injury post-RTS. A higher proportion of confident participants met all RTS criteria (p = 0.001). Confident participants were over two times more likely to suffer a second ACL injury (odds ratio [OR] = 2.40; 95% confidence interval [CI]:1.21-5.20) (p = 0.02) and participants who were both confident and met all RTS criteria were 10 times more likely to suffer a second ACL injury (OR = 9.6; 95% CI:1.1, 84.2) (p = 0.02) than those who passed all RTS criteria but lacked knee-related confidence. Clinical significance: Confident, young athletes at the time of RTS after ACLR are more likely to meet all RTS criteria and more likely to sustain a second ACL injury after RTS. Future work must consider how the inclusion of additional factors into RTS criteria may better identify those at high risk for poor outcome after ACLR.

Confidence to Return to Play After ACL Reconstruction: An Evaluation of Quadriceps Strength Symmetry and Injury Mechanism in Male Athletes

BACKGROUND

After anterior cruciate ligament reconstruction (ACLR), diminished quadriceps strength symmetry and reduced psychological readiness to return to play (RTP) increase the risk for subsequent injury. Although the relationship between quadriceps strength symmetry and psychological readiness to RTP has been reported to be influenced by injury mechanism in female athletes, it is unclear whether such a relationship exists in male athletes.

HYPOTHESIS

Quadriceps strength symmetry would be positively associated with greater psychological readiness to RTP after ACLR, regardless of injury mechanism.

STUDY DESIGN

Retrospective cohort.

LEVEL OF EVIDENCE

Level 3 (cohort study).

METHODS

Sixty male patients completed strength testing and the Injury-Psychological Readiness to Return to Sport Scale (I-PRRS) at an outpatient clinical facility as part of return to sport testing after ACLR. Linear regression analysis was used to assess the relationship between the I-PRRS and the independent variables of interest (quadriceps strength symmetry and injury mechanism).

RESULTS

For all patients combined, no symmetry × mechanism interaction was found (P = 0.11). A significant positive relationship was found between quadriceps strength symmetry and the I-PRRS score (P < 0.001, R² = 0.31), after adjusting for time post-ACLR and injury mechanism.

CONCLUSION

Greater quadriceps strength symmetry was associated with greater psychological readiness to RTP after ACLR in male athletes. In contrast to what has been reported in female athletes, this relationship was independent of injury mechanism.

CLINICAL RELEVANCE

Given the potential negative consequences of quadriceps strength deficits on one's confidence to RTP, the need to restore quadriceps symmetry during the postoperative period is readily apparent. Low confidence or low psychological readiness to RTP may be indicative of quadriceps strength asymmetry or poor physical function in general.

PSIXPORT: Mobile App for Ecological Momentary Assessment of Psychological Dimensions in Sport Injury

Retrospective self-reports have been commonly used to assess psychological variables such as feelings, thoughts, or emotions. Nevertheless, this method presents serious limitations to gather accurate information about variables that change over time. The Ecological Momentary Assessment (EMA) approach has been used to deal with some of the limitations these retrospective assessment methods present, and for gathering real-time information about dynamic psychological variables, such as feelings, thoughts, or behaviors. In the sports injury rehabilitation context, athletes' thoughts, feelings, behaviors, and pain perceptions during the rehabilitation process can influence the outcomes of this process. These responses change over different stages of the rehabilitation and taking them into account can help therapists to adapt the rehabilitation process and increasing their effectiveness. With this aim, an EMA mobile app (PSIXPORT) was designed to gather real-time information about severely injured athletes' cognitive appraisals, emotional responses, behaviors, and pain perceptions during their rehabilitation process. The goals of this study were to evaluate Psixport's ability to gather real-time information about injured athletes' psychological responses during the rehabilitation, to test the users' perceived usability of Psixport, and to compare the reliability and differences between real-time data gathered with Psixport and the data gathered through the one-time retrospective method. Twenty-eight severely injured athletes (10 men and 18 women) were assessed using Psixport, a retrospective questionnaire, and the uMARS usability test. Results showed that Psixport can be considered as a good tool to gather information about injured athletes' cognitive appraisals, emotional responses, behaviors, and pain perceptions. Moreover, multiple data assessments gathered with the app showed to be more accurate information about injured athletes' psychological responses than one-time retrospective reports.

Rationale for a Parsimonious Measure of Subjective Knee Function after ACL Reconstruction: A Rasch Analysis

CONTEXT

The International Knee Documentation Committee (IKDC) Subjective Knee Evaluation is the most frequently used patient-reported measure of subjective knee function among individuals with ACL reconstruction (ACLR). Yet, limitations with traditional validation approaches leave it unclear whether the IKDC measures knee function as intended. Rasch analysis offers a robust validation approach, which may enhance clinical interpretation of the IKDC.

OBJECTIVE

1) To assess the psychometric properties, 2) ability to classify health status, and 3) relationships between the IKDC and objective measures of strength and functional performance relative to a newly proposed reduced-item instrument.

DESIGN

Cross-sectional.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Seventy-seven individuals with primary, unilateral ACLR (21.9±7.8 years, 6.2±1.0 months post-surgery), and seventy-six age-matched controls.

MAIN OUTCOME MEASURE(S)

Rasch analysis was used to assess the psychometric properties of the IKDC. Receiver-operator-characteristic curves and logistic regression were used to assess the accuracy of classifying ACLR versus control participants. Correlations (Pearson and Spearman) were used to assess relationships between subjective knee function, quadriceps torque, and single-limb hop performance.

RESULTS

Rasch analysis aided the development of a reduced 8-item instrument (IKDC-8), which yielded improved psychometric properties in misfit analysis, percent of variance accounted for by one dimension (IKDC-8=71.5%; IKDC=56.7%), and item reliability. The IKDC was an outstanding diagnostic tool and the IKDC-8 was excellent, correctly classifying 87.2% and 82.7% of cases, respectively. The Hanley-McNeil formula found that there was no significant difference in the areas under the respective ROC curves. Equivalent associations between subjective and objective knee function were observed regardless of instrument used.

CONCLUSIONS

We observed evidence of enhanced reliability and validity for a parsimonious measure of subjective knee function. The proposed instrument reduces the number of items, increases score interpretability as measuring a single construct, and improves the rating scale functioning, while not significantly diminishing its ability to classify ACLR versus control participants or changing existing relationships with objective measures of recovery. We suggest the IKDC-8 may enhance clinical use by reducing administration time, improving the interpretation of the subjective knee function score, and clarifying functional ability.

Confidence to Return to Play After Anterior Cruciate Ligament Reconstruction Is Influenced by Quadriceps Strength Symmetry and Injury Mechanism

BACKGROUND

Although the restoration of quadriceps strength symmetry is a primary rehabilitation goal after anterior cruciate ligament reconstruction (ACLR), little is known about the potential relationship between quadriceps strength symmetry and psychological readiness to return to play (RTP).

HYPOTHESIS

Quadriceps strength symmetry will be associated with psychological readiness to RTP after ACLR. Secondarily, injury mechanism will influence the association between quadriceps strength and psychological readiness to RTP.

STUDY DESIGN

Retrospective cohort.

LEVEL OF EVIDENCE

Level 3 (cohort study).

METHODS

A total of 78 female patients completed strength testing and the Injury-Psychological Readiness to Return to Sport (I-PRRS) scale at an outpatient clinical facility as part of return to sport testing after ACLR. Linear regression analysis was used to assess the relationship between the I-PRRS and the independent variables of interest (quadriceps strength symmetry and injury mechanism).

RESULTS

For all patients combined, a significant symmetry × mechanism interaction was found. When split by injury mechanism, a significant linear relationship was found between quadriceps strength symmetry and the I-PRRS score in patients who experienced a noncontact injury (n = 55; P = 0.01; R² = 0.24). No such relationship was found for those who experienced a contact injury (n = 23; P = 0.97; R² = 0.01).

CONCLUSION

Greater quadriceps strength symmetry was associated with greater psychological readiness to RTP in female athletes after ACLR. This relationship, however, was present only in those who experienced a noncontact injury.

CLINICAL RELEVANCE

Clinicians should consider both the physical and the psychological factors in assessing a patient's readiness to RTP. This may be particularly important for those who have experienced an ACL tear through a noncontact mechanism.

Assessment of Quadriceps Corticomotor and Spinal-Reflexive Excitability in Individuals with a History of Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis

BACKGROUND

Differences in the excitability of motor generating neural pathways are reported following anterior cruciate ligament reconstruction (ACLR) that is associated with quadriceps dysfunction and theorized to prevent the full recovery of muscle function.

OBJECTIVE

The aims of this systematic review and meta-analysis were to compare quadriceps neural excitability between the involved ACLR limb, the uninvolved limb, and uninjured controls, and to determine at what time intervals these differences are present after surgery.

METHODS

We conducted a search of PubMed, SPORTDiscus, Embase, and Web of Science, and extracted measures assessing difference of quadriceps spinal-reflexive, corticospinal, and intracortical excitability from studies that compared (1) involved limb to the uninvolved limb, (2) involved limb to a control limb, or (3) uninvolved limb to a control limb. We stratified time at 24 months, since this represents a period of heightened risk for reinjury. A modified Downs and Black checklist and Egger's test were used to determine the methodological quality of individual studies and risk of bias between studies.

RESULTS

Fourteen studies comprising 611 participants (371 individuals with a history of ACLR; median time from surgery: 31.5 months; range 0.5-221.1 months) were included in the review. Overall, the involved (g = 0.60, 95% CI [0.24, 0.96]) and uninvolved (g = 0.49, 95% CI [0.00, 0.98]) limbs exhibited greater motor threshold (MT) in comparison to uninjured controls. Motor-evoked potential (MEP) amplitudes were greater in the uninvolved limb in comparison to uninjured controls (g = 0.31, 95% CI [0.03, 0.59]). Lesser intracortical inhibition was exhibited in the uninvolved limb compared to uninjured controls (g = 0.54, 95% CI [0.14, 0.93]). When stratified by time from surgery, MEP amplitudes were greater in the uninvolved limb compared to uninjured controls (g = 0.33, 95% CI [0.03, 0.63]) within the first 24 months after surgery. When evaluated more than 24 months after surgery, the involved limb exhibited greater Hoffmann reflex (H-reflex) compared to uninjured controls (g = 0.38, 95% CI [0.00, 0.77]). MT were greater in the involved limb (g = 0.93, 95% CI [- 0.01, 1.88]) and uninvolved limb (g = 0.57, 95% CI [0.13, 1.02]) compared to uninjured controls. MEP amplitudes in the involved limb were lesser compared to uninjured controls when evaluated more than 24 months after ACLR (g = -1.11, 95% CI [- 2.03, - 0.20]).

CONCLUSIONS

The available evidence supports that there are neural excitability differences within the corticospinal tract in individuals with ACLR when compared to uninjured controls. Future research should focus further on longitudinal assessments of neural excitability prior to and following ACLR. Identifying interventions aimed to facilitate corticospinal excitability after ACLR appears to be warranted to improve quadriceps function.

TRIAL REGISTRATION

Registered through PROSPERO CRD42020158714.

What Are Our Patients Really Telling Us? Psychological Constructs Associated With Patient-Reported Outcomes After Anterior Cruciate Ligament Reconstruction

CONTEXT

Depressed patient-reported outcomes (PROs) are directly related to suboptimal recovery after anterior cruciate ligament reconstruction (ACLR). Various PROs commonly used after ACLR can provide a gross estimation of function but do not fully elucidate the causes of self-perceived disability.

OBJECTIVE

To more fully characterize the factors driving responses on PROs.

DESIGN

Cross-sectional study. A mixed-methods approach was used, in which qualitative interviews were conducted alongside administration of PROs to uncover the themes behind a participant's PRO responses.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twenty-one individuals with unilateral ACLR (age = 20.90 ± 2.86 years, height = 172.0 ± 11.03 cm; mass = 71.52 ± 13.59 kg, postsurgery = 3.66 ± 3.03 years).

MAIN OUTCOME MEASURE(S)

Patient-reported outcome measures were administered and qualitative interviews were conducted. The PROs consisted of the International Knee Documentation Committee form, Knee Injury and Osteoarthritis Outcomes Score (KOOS), ACL-Return to Sport after Injury (ACL-RSI) scale, and Tampa Scale of Kinesiophobia (TSK). A hierarchical cluster analysis was used to identify subgroups based on PRO responses. Qualitative interviews provided supplemental insight into perceived disability. Independent t tests examined cluster differences for themes. Spearman ρ correlations indicated associations between PRO responses and themes.

RESULTS

Two clusters (perceived high or low disability) emerged. Individuals with low perceived disability scored better on all PROs (P < .05) except for the KOOS-Activities of Daily Living. Internal and external facilitators or barrier subthemes emerged from the interviews. A significant difference was present between clusters and themes. Lower TSK andgreater ACL-RSI and KOOS-Quality of Life scores were associated with more perceived facilitators.

CONCLUSIONS

Participants with greater internal motivation and confidence and a support network had improved PROs. Those with avoidance tendencies, fear, lack of clear expectations, and less social support scored worse on PROs. The TSK, ACL-RSI, and KOOS-Quality of Life scales were best able to capture the constructs associated with perceived wellness, which reinforces their utility in recovery.

Factors Associated With Psychological Readiness to Return to Sports With Cutting, Pivoting, and Jump-Landings After Primary ACL Reconstruction

Background:

High psychological readiness is an important element for returning to sports after anterior cruciate ligament (ACL) reconstruction. Identifying factors that contribute to psychological readiness is essential for planning interventions to return to play. No studies have used multivariate analysis to clarify factors associated with psychological readiness to return to specific sports.

Hypothesis:

To identify factors that contribute to an athlete’s psychological readiness to return after ACL reconstruction to sports that require cutting, pivoting, and jump-landings.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Study participants were athletes who before injury had participated in sports with limited contact that required cutting, pivoting, and jump-landings (basketball, soccer, futsal, volleyball, badminton, tennis, and frisbee) and hoped to return to the same sport after reconstruction. Psychological readiness was measured using the Anterior Cruciate Ligament–Return to Sport After Injury Scale (ACL-RSI) in athletes more than 6 months after primary ACL reconstruction. To clarify factors associated with the ACL-RSI, univariate regression analysis and multivariate regression analysis were performed using the following independent variables: age, sex, body mass index, time from injury to reconstruction, time from reconstruction to testing, meniscal surgery, modified Tegner activity scale before injury, kinesiophobia, limb symmetry index of knee strength, limb symmetry indices of single-leg hop (SLH) distances, and subjective running ability.

Results:

Higher subjective running ability, a lower kinesiophobia score, and greater limb symmetry in the lateral SLH were positively associated with psychological readiness.

Conclusion:

The psychological readiness of athletes aiming to return after ACL reconstruction to limited-contact sports that require cutting, pivoting, and jump-landings was affected by subjective running ability, kinesiophobia, and asymmetry of lateral SLH distance. This information may be useful in planning appropriate interventions and thereby increasing the likelihood of an athlete’s returning to such sports.

A comparative analysis of the efficacy of anterior cruciate ligament reconstruction with autologous ligament grafting at different time points

BACKGROUND

This study was performed to compare the clinical efficacies of anterior cruciate ligament (ACL) reconstruction with autologous ligament grafting at different time points.

METHODS

Eighty-five patients with ACL were categorized into two groups: Group A (GA, n = 45), who underwent early-stage (≤3 weeks) surgery, and Group B (GB, n = 40), who underwent advanced-stage (>3 weeks) surgery. Perioperative conditions, knee joint functions, activity and stability before and at 6 months postoperatively, changes in quality of life (QOL), good and excellent rates of knee joint functions, and incidence of complications were compared between the two groups.

RESULTS

In both groups, there was an increase in the International Knee Documentation Committee (IKDC) score, Lysholm score, and QOL and a decrease in the knee joint angle flexion limitation, angle of spread limitation, positive rates in the anterior drawer test (ADT), and Lachman test score (P < .05) after surgery. At 6 months postoperatively, the IKDC score, Lysholm score, and QOL were higher in GA than in GB (P < .05). The good and excellent rates of knee joint functions were higher in GA than in GB (93.33% vs. 77.50%) (P < .05).

CONCLUSION

Anterior cruciate ligament reconstruction with autologous ligament grafting can achieve good effects whether performed in the early or advanced stage; however, the improvements in patients' knee joint functions and QOL are better in the early stage. Therefore, early ACL reconstruction with autologous ligament grafting is suggested.

Hop tests can result in higher limb symmetry index values than isokinetic strength and leg press tests in patients following ACL reconstruction

PURPOSE

Quadriceps weakness is a common clinical sign following anterior cruciate ligament injury and reconstruction surgery (ACLR). The aim of this study was to compare strength deficits and the limb symmetry index (LSI) from three different types of functional tests: isokinetic dynamometry, hop test, and leg press.

METHODS

A total of 26 subjects with ACLR (average 8.3 months post-operation) participated in the study. The peak knee extension torque was tested with isokinetic dynamometry at 60/180/300 °/s (ISO60/180/300). Hop distance was tested during single hop (SH) and triple hop (TH). Unilateral peak leg power (POWER) was tested during a bilateral leg press test. LSI was calculated as the ratio of the involved limb over the uninvolved limb values. Pearson correlation coefficients and paired t-tests were used to establish relationships among ISO60/180/300, SH/TH, and POWER values and compare these values between the limbs, respectively. Within-subject one-way analysis of variance (ANOVA) with post hoc analyses was used to compare LSI values among different tests.

RESULTS

ISO60/180/300 values were significantly positively correlated with SH/TH and POWER (P < 0.05), while SH/TH and POWER values were not significantly correlated. Significant limb differences were found in all tests (P = 0.001-0.008). ANOVA revealed significant LSI differences among different tests. Specifically, post hoc analyses revealed that LSI during SH was significantly higher than LSI during ISO60. Similarly, LSI during TH was significantly higher than LSIs from ISO60, ISO180, and POWER tests.

CONCLUSIONS

Peak knee extension torque values were positively associated with hop distance and leg power during the leg press test. However, LSI values should be interpreted with caution as hop tests provided significantly higher LSI values than isokinetic testing. Both isokinetic dynamometry and unilateral leg press machine could be used to isolate and strengthen the quadriceps in the involved limb. The current "gold standard" isokinetic testing at slow speed (ISO60) provided the lowest LSI value among all functional tests; therefore, the current study supported a continued use of isokinetic testing when examining individual's readiness and return-to-sport.

LEVEL OF EVIDENCE

III.

Quadriceps Muscle Size Following ACL Injury and Reconstruction: A Systematic Review

Image-based assessments of quadriceps muscle size facilitate examination of structural changes after anterior cruciate ligament (ACL) injury and reconstruction (ACLR). Understanding the effects of ACLR on muscle size measures may aid in clarifying the contribution of quadriceps atrophy toward quadriceps strength. The purpose of this study was to systematically review the literature examining the effects of ACLR on quadriceps muscle volume and cross-sectional area (CSA). An online database search was conducted using Web of Science, SportDISCUS, PubMed (Medline), CINHAL (EBSCO), and Cochrane Library limited to articles published after January 1, 1980. Means and standard deviations were extracted for the ACLR limb and the contralateral limb, and sample characteristics from relevant articles. Magnitude of between limb differences were assessed using pooled effect sizes (Hedge's g) and 95% confidence intervals. Eleven articles (five CSA, six muscle volume) were included in this systematic review. Included studies reported negative effective sizes, indicating that the ACLR limb was smaller in CSA or muscle volume compared with the contralateral limb; however, 36% of the included articles reported meaningful difference between the limbs. Quadriceps atrophy may occur following ACL injury and persist after rehabilitation, however, the magnitude of these reductions may not be clinically meaningful and may only partially explain the persistent quadriceps weakness that is ubiquitous among this patient population. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:598-608, 2020.

Psychological, social and contextual factors across recovery stages following a sport-related knee injury: a scoping review

Objective

To explore the role of psychological, social and contextual factors across the recovery stages (ie, acute, rehabilitation or return to sport (RTS)) following a traumatic time-loss sport-related knee injury.

Material and methods

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews and Arksey and O’Malley framework. Six databases were searched using predetermined search terms. Included studies consisted of original data written in English that identified or described a psychological, social or contextual factor related to recovery after a traumatic time-loss sport-related knee injury. Two authors independently conducted title–abstract and full-text reviews. Study quality was assessed using the Mixed Methods Appraisal Tool. Thematic analysis was undertaken.

Results

Of 7289 records, 77 studies representing 5540 participants (37% women, 84% anterior cruciate ligament tears, aged 14–60 years) were included. Psychological factors were investigated across all studies, while social and contextual factors were assessed in 39% and 21% of included studies, respectively. A cross-cutting concept of individualisation was present across four psychological (barriers to progress, active coping, independence and recovery expectations), two social (social support and engagement in care) and two contextual (environmental influences and sport culture) themes. Athletes report multiple barriers to recovery and valued their autonomy, having an active role in their recovery and diverse social support.

Conclusion

Diverse psychological, social and contextual factors are present and influence all stages of recovery following a traumatic sport-related knee injury. A better understanding of these factors at the time of injury and throughout rehabilitation could assist with optimising injury management, promoting RTS, and long-term health-related quality-of-life.

The immediate effects of passive joint mobilisation on local muscle function. A systematic review of the literature

BACKGROUND

Passive joint mobilisation is popular among healthcare providers and their patients; however, its effectiveness for improving muscle function is not well researched and the mechanisms of action involved are unclear.

OBJECTIVES

To assess the effect of passive joint mobilisations on the function of muscles surrounding the targeted joints in symptomatic as well as asymptomatic individuals.

SELECTION CRITERIA

Controlled experimental trials assessing the immediate effect of passive joint mobilisation on outcomes associated with local muscle function.

DATA COLLECTION

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

A total of seventeen studies were included, of which ten studies reported data on asymptomatic individuals and seven studies reported data on symptomatic individuals with various conditions. There is a moderate level of evidence that joint mobilisation immediately decreases the activation of superficial muscles during low load conditions in symptomatic individuals. For asymptomatic individuals, there is a low level of evidence that passive joint mobilisation improves maximum muscle strength when compared to sham mobilisation, opposed to a very low level of evidence suggesting no effect in symptomatic individuals. The five studies reporting data on both, changes in muscle function as well as changes in pain, suggest that other, not pain-related mechanisms may play an important role regarding the reported improvement in muscle function.

CONCLUSION

Current best evidence suggests that passive joint mobilisation has the ability to immediately alter muscle function. The specific mechanisms of action involved require further basic science investigations. Registration number (PROSPERO): CRD42018117033.

Alterations in physical and neurocognitive wellness across recovery after ACLR: A preliminary look into learned helplessness

OBJECTIVES

Neural alterations after anterior cruciate ligament reconstruction (ACLR) may initiate a maladaptive neurocognitive response (learned helplessness [LH]). Understanding the interrelationships between neural inhibition, quadriceps function and psychological responses can provide clinicians areas to target during recovery. The purpose was to longitudinally evaluate neural excitability, strength and self-reported LH after ACL injury and to explore the relationship between these measures and knee mechanics and patient reported function.

DESIGN

Case-series.

SETTING

University.

PARTICIPANTS

Eight patients were evaluated across recovery after ACL injury.

MAIN OUTCOME MEASURES

Neural activity, quadriceps function, and self-reported LH were evaluated at pre-surgery, 3-months post-ACLR and at the time of return to play (RTP).

RESULTS

Patients presented with higher helplessness between 3-months and RTP. Neural excitability and quadriceps function were variable and associated with various aspects of LH. These findings indicate a systemic inability to generate appropriate neural signaling to the quadriceps and highlights how these changes may influence perceived helplessness and overall function after ACLR.

CONCLUSIONS

LH is related to both measures of physical function and neural outcomes and varies across recovery. This may provide clinicians with a feasible clinical tool that has the potential to identify a variety of impairments arising after ACLR.

Predicting post-operative functional ability from pre-operative measures in ACL-injured individuals

PURPOSE

This study aimed to quantify the relationship between objective and subjective measures of functional ability and determine if measures in the deficient (ACLd) state were correlated to, and capable of predicting a patient's objective and subjective measures in the reconstructed (ACLr) state.

METHODS

Twenty ACL-injured participants completed hop and side cut movements prior to and 10 months post-reconstruction. Their subjective measures (Tegner, Lysholm, IKDC, KOOS, and KNEEs) were related to objective measures of functional ability (peak knee flexion, peak knee extensor moment, stiffness, knee joint center excursion (KJCE), and knee joint center boundary). Correlations were used to determine relationships between variables whereas regressions were used to identify ACLd score's predictive ability of an ACLr score.

RESULTS

Relationships between objective and subjective measures were task and ACL status dependent with KJCE and stiffness most commonly being related to subjective scores. The greatest correlation was between knee stiffness and Tegner in the ACLr group during the side cut (r = 0.69). Peak knee flexion angle (adj. R²  = 0.4-0.66) was the best objective predictor between ACLd and ACLr states while KOOS-ADL had the strongest correlations (r = 0.70-0.77) and Tegner had the greatest predictive power (odds ratio: 1.46-1.86) between states in both tasks.

CONCLUSION

Objective measures show a wide range of correlation to subjective measures with some being quite strong. Furthermore, objective measures in the ACLd state are more correlated and more often capable of predicting ACLr scores than the subjective measures of functional ability.

Psychosocial Barriers After Anterior Cruciate Ligament Reconstruction: A Clinical Review of Factors Influencing Postoperative Success

CONTEXT

Psychosocial factors arising after anterior cruciate ligament (ACL) injury may have a direct influence on an individual's decision to return to sport after ACL reconstruction (ACLR). While there is ample evidence to suggest that deficits in quadriceps strength, neuromuscular control, and clinical functional tasks exist after ACLR, the root and contribution of psychological dysfunction to an individual's success or return to sport after ACLR is still largely uncertain and unexplored. Given the discrepancy between successful functional outcomes and the percentage of athletes who return to sport, it is important to thoroughly address underlying factors, aside from physical function, that may be contributing to these lower return rates.

EVIDENCE ACQUISITION

Articles that reported on return to sport, psychological factors, and psychosocial factors after ACLR were collected from peer-reviewed sources available on Medline (1998 through August 2018). Search terms included the following: anterior cruciate ligament OR ACL AND return-to-sport OR return-to-activity, anterior cruciate ligament OR ACL AND psychological OR psychosocial OR biopsychosocial OR fear OR kinesiophobia OR self-efficacy, return-to-activity AND psychological OR psychosocial.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 5.

RESULTS

Psychosocial factors relative to injury are important components of the rehabilitation process. To fully understand how psychosocial factors potentially influence return to sport, an athlete's emotions, experiences, and perceptions during the rehabilitation process must be acknowledged and taken into consideration.

CONCLUSION

Acknowledgment of these psychosocial factors allows clinicians to have a better understanding of readiness to return to sport from a psychological perspective. Merging of the current ACLR rehabilitation protocols with knowledge related to psychosocial factors creates a more dynamic, comprehensive approach in creating a positive and successful rehabilitation environment, which may help improve return-to-sport rates in individuals after ACLR.

Reactive Strength Index and Knee Extension Strength Characteristics Are Predictive of Single-Leg Hop Performance After Anterior Cruciate Ligament Reconstruction

Birchmeier, T, Lisee, C, Geers, B, and Kuenze, C. Reactive strength index and knee extension strength characteristics are predictive of single-leg hop performance after anterior cruciate ligament reconstruction. J Strength Cond Res 33(5): 1201-1207, 2019-Single-leg hop distance is incorporated into return to sport criteria after anterior cruciate ligament reconstruction (ACLR) because of its relationship with knee extension strength; however, it may be related to other strength and plyometric characteristics. The purpose of this study was to assess the association between isometric knee extension strength and plyometric characteristics, including amortization and reactive strength index (RSI), measured during a single-leg drop vertical jump and single-leg hop performance in individuals with unilateral ACLR. Participants attended 2 testing sessions. During the first session, a biomechanical analysis using a 3D motion capture system was performed to measure RSI and amortization during a single-leg drop vertical jump for maximal height. Participants completed a single hop and a triple hop for maximal distance. During the second session, isometric knee extension strength was measured during a maximal voluntary isometric contraction. Strength characteristics included peak torque, rate of torque development (RTD), RTD 0-100 ms (RTD 100), and RTD 100-200 ms (RTD 200). Fifty-two individuals (17 men/35 women) participated. Multivariable regression models revealed jump height, peak torque, and RTD 200 explained 60.9% of the variance in normalized single-leg hop distance (p < 0.001). Reactive strength index, peak torque, RTD 200, and RTD 100 significantly explained 61.8% of the variance in normalized triple hop distance (p < 0.001). Single hop distance may indicate improved knee extension strength, whereas triple hop distance may indicate improvement in reactive strength. Training to improve RSI may improve triple hop performance and clinical outcomes in this population.

Clinical and radiographic results of partial versus total meniscectomy in patients with symptomatic discoid lateral meniscus: A systematic review and meta-analysis

PURPOSE

Some reports have noted favorable long-term clinical results with milder postoperative arthritic changes after total meniscectomy in symptomatic patients with torn discoid lateral meniscus (DLM). This meta-analysis was conducted to compare the clinical and radiographic results between partial and total meniscectomy in patients with symptomatic DLM.

METHODS

Studies were included in the meta-analysis if (1) they analysed patients who underwent arthroscopic surgeries for DLMs, (2) they directly compared clinical outcomes in patients treated with partial and total meniscectomies, (3) they analysed at least one parameter related to postoperative outcomes, including the Ikeuchi scale, and/or radiographic results including the Tapper and Hoover classification.

RESULTS

Eight studies were finally included. The proportion of the knees with excellent or good grade appeared to be higher in partial than in total meniscectomy group, but this difference did not reach statistical significance [128/158 (81.0%) vs. 87/131 (66.4%); OR 1.62; p=0.10; I²=0%]. The pooled results of the proportion of normal cartilage status or mild chondral wear (grade 0 or 1 of the Tapper and Hoover classification) were significantly much higher with partial than with total meniscectomy [228/261 (87.4%) vs. 94/169 (55.6%); OR 9.08; p<0.001; I²=57%].

CONCLUSION

This meta-analysis showed that the radiographic outcomes of DLM were better with partial meniscectomy with or without repair than with total meniscectomy, but their clinical outcomes were similar. The findings thus suggest that meniscal preservation would be a better option than total meniscectomy for symptomatic DLM.

LEVEL OF EVIDENCE

II, Systematic review and Meta-analysis.