Assessing Physical Activity After ACL Injury: Moving Beyond Return to Sport

Longitudinal changes in adiposity following anterior cruciate ligament reconstruction and associations with knee symptoms and function

Objective

To evaluate adiposity after anterior cruciate ligament reconstruction (ACLR): i) cross-sectionally (1-year post-ACLR) compared to uninjured controls; ii) longitudinally up to 5 years post-ACLR; and iii) associations with patient-reported symptoms and physical performance.

Methods

In 107 individuals post-ACLR and 19 controls, we assessed global (BMI), peripheral (subcutaneous adipose tissue thickness on the posteromedial side of knee MRI), and central (waist circumference in ACLR group) adiposity. Patient-reported symptoms (Knee injury and Osteoarthritis Outcome Score) and physical performance (hop for distance) were evaluated at 1 and 5 years post-ACLR. Linear regression models evaluated adiposity between groups. Paired t-tests evaluated changes in adiposity from 1- to 5 years post-ACLR. Linear regression models analyzed adiposity's associations with patient-reported symptoms and physical performance at 1-year post-ACLR, changes in symptoms and performance over 4 years post-ACLR, and longitudinal changes in adiposity and symptoms and performance, controlling for age, sex, and activity level.

Results

Individuals 1-year post-ACLR were associated with higher average global (3 ​kg/m2) and peripheral adiposity (2.3 ​mm). From 1- to 5 years post-ACLR, higher average global (0.58 ​kg/m2) and central (5 ​cm) adiposity, and lower average peripheral adiposity (1.3 ​mm) were observed. In general, adiposity at one-year post-ACLR was negatively associated with patient-reported symptoms and physical performance, and changes from 1 to 5 years post-ACLR. Increases in adiposity were negatively associated with changes in patient-reported symptoms and physical performance over four years post-ACLR.

Conclusion

Greater global and central adiposity is a feature of young adults following ACLR and influences current and future patient-reported symptoms and physical performance.

Objectively evaluated physical activity among individuals following anterior cruciate ligament reconstruction: a systematic review and meta-analysis

Objective

To compare time spent in moderate-to-vigorous physical activity (MVPA) per week, MVPA per day, and steps per day between individuals that were subjected to the anterior cruciate ligament reconstruction (ACLR) and healthy control group.

Design

Systematic review and meta-analysis of observational studies.

Data sources

Web of Science, Scopus, and PubMed have been comprehensively searched to identify relevant investigations.

Eligibility criteria for selecting studies

An observational research that objectively evaluated physical activity among respondents with a history of ACLR.

Results

Of 302 records, a total of 12 studies fulfilled the eligibility criteria. Four hundred and forty-three participants underwent the ACLR, 153 men and 290 women. The mean time between anterior cruciate ligament (ACL) surgery and evaluation of analysed outcomes was 34.8 months. The main findings demonstrated that the ACLR group spent less time in weekly MVPA (standardised mean differences (SMD)=-0.43 (95% CI -0.66 to -0.20); mean = -55.86 min (95% CI -86.45 to -25.27); p=0.0003; τ2=0.00), in daily MVPA (SMD=-0.51 95% CI -0.76 to -0.26]; mean = -15.59 min (95% CI -22.93 to -8.25); p<0.0001; τ2=0.00), and they had fewer daily steps (SMD=-0.60 95% CI -0.90 to -0.30); mean = -1724.39 steps (95% CI -2552.27 to -896.50); p<0.0001; τ2=0.00) relative to their non-injured counterparts. Additionally, available investigations indicated that individuals with a history of ACLR participated in 316.8 min of MVPA per week, 67 min in MVPA per day, and 8337 steps per day.

Conclusion

Long-term after ACLR, participants undergoing ACL surgery were less physically active compared with their non-injured peers, and they did not satisfy recommendations regarding steps per day.

PROSPERO registration number

CRD42023431991.

The influence of body mass index on physical activity engagement following anterior cruciate ligament reconstruction: A systematic literature review

Background

The objective of this study was to summarize available literature that explored the impact of body mass index (BMI) on physical activity participation among individuals who were subjected to the anterior cruciate ligament reconstruction (ACLR).

Methods

A total of three electronic databases, including Web of Science, Scopus, and PubMed, were comprehensively searched to identify relevant investigations. The following inclusion criteria were applied: (1) study design was observational; (2) participants underwent the ACLR; (3) BMI was estimated as a predictor variable; and (4) outcomes evaluated referred to physical activity. The risk of bias was assessed with the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies.

Results

After a database search, 787 studies were found, and only 10 of them met each of the eligibility criteria and were included in the qualitative analysis. Regarding respondents' characteristics, 7171 individuals underwent ACLR, 4080 males and 3091 females, with a mean age of 25.5 years. Most importantly, the average BMI of the examined population was 24.9 kg/m2. In all studies, physical activity was evaluated subjectively using the Tegner activity scale and the Marx activity scale. The main findings unambiguously demonstrated that a negative relationship between BMI and physical activity engagement was observed. More specifically, there is convincing evidence that BMI over 25 kg/m2 harmfully affected subjectively assessed physical activity in individuals with a history of ACLR.

Conclusion

The results obtained in the presented research indicated that increased values of BMI were a factor that correlated with reduced physical activity levels in the ACLR population. Hence, taking into account the clinical and health implications of reduced physical activity participation, stimulation of a healthy lifestyle, such as a combination of adequately designed physical exercise and nutrition, seems necessary for the analyzed population.

Accelerometer-assessed physical activity patterns during the first two years after a non-surgically treated ACL injury

OBJECTIVES

To describe physical activity patterns and analyze changes during the first two years after a non-surgically treated ACL injury, and to assess correlations between accelerometer-assessed physical activity and self-reported knee function and knee-related quality of life.

DESIGN

Prospective cohort study.

PARTICIPANTS

128 patients (61 females, 25.2 ± 7.1 years) with acute ACL injury.

MAIN OUTCOME MEASURES

Physical activity patterns were measured with accelerometry. Self-reported knee function was assessed using the International Knee Documentation Committee Subjective Knee Form, and knee-related quality of life was assessed using the Anterior Cruciate Ligament Quality of Life questionnaire.

RESULTS

Moderate to vigorous physical activity (MVPA) and steps per day increased from baseline to 3 months (p < .001), with no further increase from 3 to 24 months (p > .05). Time in MVPA did not correlate to patient-reported outcome measures at 3, 6, 12, or 24 months (p > .05).

CONCLUSIONS

Physical activity increased from acute phase to 3 months after non-surgically treated ACL injury, but almost one in four patients did not reach recommended levels of physical activity. Physical activity did not correlate with knee function or quality of life. Patients may need improved support to return to physical activity after ACL injury.

LEVEL OF EVIDENCE

Level II.

TRIAL REGISTRATION

NCT02931084.

Joint and Limb Loading during Gait in Adults with ACL Reconstruction: Comparison between Single-Step and Cumulative Load Metrics

PURPOSE

Individuals with anterior cruciate ligament reconstruction (ACLR) generally exhibit limb underloading behaviors during walking, but most research focuses on per-step comparisons. Cumulative loading metrics offer unique insight into joint loading as magnitude, duration, and total steps are considered, but few studies have evaluated if cumulative loads are altered post-ACLR. Here, we evaluated if underloading behaviors are apparent in ACLR limbs when using cumulative load metrics and how load metrics change in response to walking speed modifications.

METHODS

Treadmill walking biomechanics were evaluated in 21 participants with ACLR at three speeds (self-selected (SS); 120% SS and 80% SS). Cumulative loads per step and per kilometer were calculated using knee flexion and adduction moment (KFM and KAM) and vertical ground reaction force (GRF) impulses. Traditional magnitude metrics for KFM, KAM, and GRF were also calculated.

RESULTS

The ACLR limb displayed smaller KFM and GRF in early and late stances, but larger KFM and GRF during midstance compared with the contralateral limb ( P < 0.01). Only GRF cumulative loads (per step and per kilometer) were reduced in the ACLR limb ( P < 0.01). In response to speed modifications, load magnitudes generally increased with speed. Conversely, cumulative load metrics (per step and per kilometer) decreased at faster speeds and increased at slow speeds ( P < 0.01).

CONCLUSIONS

Patients with ACLR underload their knee in the sagittal plane per step, but cumulatively over the course of many steps/distance, this underloading phenomenon was not apparent. Furthermore, cumulative load increased at slower speeds, opposite to what is identified with traditional single-step metrics. Assessing cumulative load metrics may offer additional insight into how load outcomes may be impacted in injured populations or in response to gait modifications.

Youth sport participation, injury history, and current physical activity among young adults

Objective: To examine the interaction between high school (HS) sports participation and injury history with current moderate-to-vigorous physical activity (MVPA) among young adults. Participants: Participants (N = 236) were 18-25 years old, not currently injured, and reported no physical activity limitations. Methods: Participants completed online demographic, injury history, and physical activity surveys. A two-way analysis of covariance was used to test the interaction between HS athlete status and previous injury severity on current self-reported MVPA. Results: Participants were 22.2 ± 2.1 years, primarily White (81.8%) or Asian (6.4%), and female (77.5%). After including body mass index and race as covariates, there was a statistically significant interaction between HS athlete status and previous injury history such that current MVPA was higher among former HS athletes compared to HS recreational/nonathletes when individuals reported no injuries or mild injury severity. MVPA was similar across athlete status groups when participants reported high levels of injury severity. Conclusions: Future studies should examine whether young adults who have experienced multiple and/or severe injuries as competitive HS athletes have unique physical activity barriers.

Let's talk about sex (and gender) after ACL injury: a systematic review and meta-analysis of self-reported activity and knee-related outcomes

OBJECTIVE

Investigate sex/gender differences in self-reported activity and knee-related outcomes after anterior cruciate ligament (ACL) injury.

DESIGN

Systematic review with meta-analysis.

DATA SOURCES

Seven databases were searched in December 2021.

ELIGIBILITY CRITERIA

Observational or interventional studies with self-reported activity (including return to sport) or knee-related outcomes after ACL injury.

RESULTS

We included 242 studies (n=123 687, 43% females/women/girls, mean age 26 years at surgery). One hundred and six studies contributed to 1 of 35 meta-analyses (n=59 552). After ACL injury/reconstruction, very low-certainty evidence suggests females/women/girls had inferior self-reported activity (ie, return to sport, Tegner Activity Score, Marx Activity Scale) compared with males/men/boys on most (88%, 7/8) meta-analyses. Females/women/girls had 23%-25% reduced odds of returning to sport within 1-year post-ACL injury/reconstruction (12 studies, OR 0.76 95% CI 0.63 to 0.92), 1-5 years (45 studies, OR 0.75 95% CI 0.69 to 0.82) and 5-10 years (9 studies, OR 0.77 95% CI 0.57 to 1.04). Age-stratified analysis (<19 years) suggests female athletes/girls had 32% reduced odds of returning to sport compared with male athletes/boys (OR 0.68, 95% CI 0.41 to 1.13, I² 0.0%). Very low-certainty evidence suggests females/women/girls experienced inferior knee-related outcomes (eg, function, quality of life) on many (70%, 19/27) meta-analyses: standardised mean difference ranging from -0.02 (Knee injury and Osteoarthritis Outcome Score, KOOS-activities of daily living, 9 studies, 95% CI -0.05 to 0.02) to -0.31 (KOOS-sport and recreation, 7 studies, 95% CI -0.36 to -0.26).

CONCLUSIONS

Very low-certainty evidence suggests inferior self-reported activity and knee-related outcomes for females/women/girls compared with males/men/boys after an ACL injury. Future studies should explore factors and design targeted interventions to improve outcomes for females/women/girls.

PROSPERO REGISTRATION NUMBER

CRD42021205998.

Evidence Review for Preventing Osteoarthritis After an Anterior Cruciate Ligament Injury: An Osteoarthritis Action Alliance Consensus Statement

CONTEXT

The Osteoarthritis Action Alliance formed a secondary prevention task group to develop a consensus on secondary prevention recommendations to reduce the risk of osteoarthritis after a knee injury.

OBJECTIVE

Our goal was to provide clinicians with secondary prevention recommendations that are intended to reduce the risk of osteoarthritis after a person has sustained an anterior cruciate ligament injury. Specifically, this manuscript describes our methods, literature reviews, and dissenting opinions to elaborate on the rationale for our recommendations and to identify critical gaps.

DESIGN

Consensus process.

SETTING

Virtual video conference calls and online voting.

PATIENTS OR OTHER PARTICIPANTS

The Secondary Prevention Task Group consisted of 29 members from various clinical backgrounds.

MAIN OUTCOME MEASURE(S)

The group initially convened online in August 2020 to discuss the target population, goals, and key topics. After a second call, the task group divided into 9 subgroups to draft the recommendations and supportive text for crucial content areas. Twenty-one members completed 2 rounds of voting and revising the recommendations and supportive text between February and April 2021. A virtual meeting was held to review the wording of the recommendations and obtain final votes. We defined consensus as >80% of voting members supporting a proposed recommendation.

RESULTS

The group achieved consensus on 15 of 16 recommendations. The recommendations address patient education, exercise and rehabilitation, psychological skills training, graded-exposure therapy, cognitive-behavioral counseling (lacked consensus), outcomes to monitor, secondary injury prevention, system-level social support, leveraging technology, and coordinated care models.

CONCLUSIONS

This consensus statement reflects information synthesized from an interdisciplinary group of experts based on the best available evidence from the literature or personal experience. We hope this document raises awareness among clinicians and researchers to take steps to mitigate the risk of osteoarthritis after an anterior cruciate ligament injury.

Patients that maintain their pre-injury level of physical activity 3-5 years after ACL reconstruction are, 18 months after surgery, characterised by higher levels of readiness to return to sport

PURPOSE

To characterise patients who had returned to their pre-injury physical activity (PA) or higher at 18 months and maintained that level of PA 3-5 years after the primary ACL reconstruction and to describe the level, frequency, and type of PA participation during the first 5 years after ACL reconstruction  METHOD: Data, from follow-ups at 18 months and 3-5 years after an ACL reconstruction, were extracted from a rehabilitation-specific register. Patients, 15-65 years of age, were included. The data comprised patient-reported outcomes and the results from two questions with respect to the level, frequency, and type of PA. Comparisons were made between patients who had and had not maintained their pre-injury level of PA at the follow-up 3-5 years after an ACL reconstruction.

RESULTS

A total of 272 patients met the inclusion criteria. The mean follow-up time was 3.8 years (min-max: 2.9-5.1) after the ACL reconstruction. Of patients who had returned to their pre-injury or a higher level of PA at the 18 month follow-up (n = 114), 68% (n = 78) maintained that level at the 3- to 5-year follow-up after ACL reconstruction. These patients reported a higher level of psychological readiness to return to sport (98 versus 79; p = 0.013). Moreover, these patients were 6.0 years older (p = 0.016) and were characterised by male sex (56% versus 44%; p = 0.028) and a lower level of pre-injury PA (p = 0.013). At the follow-up 3-5 years after the ACL reconstruction, more than 90% met the recommendations for PA. However, the prevalence of physical inactivity had increased and the involvement in organised PA had decreased compared with the 18-month follow-up.

CONCLUSIONS

Two out of three patients who have returned to their previous level of PA at 18 months can be expected to maintain that level, 3-5 years following ACL reconstruction. These patients were mainly characterised by a higher level of psychological readiness, especially in patients who participated in knee-strenuous sport and were younger than 20 years of age. The results of this study suggest that patients become more physically inactive over time, implicating the importance of clinicians helping patients find a suitable PA that may help patients maintain an active lifestyle.

Understanding Youth Sport Coaches' Perceptions of Evidence-Based Injury-Prevention Training Programs: A Systematic Literature Review

OBJECTIVE

To systematically review and summarize the knowledge, attitudes, beliefs, and contextual perceptions of youth sport coaches toward injury-prevention training programs by using the Theoretical Domains Framework to guide the organization of results.

DATA SOURCES

Systematic searches of PubMed and Google Scholar were undertaken in November 2021.

STUDY SELECTION

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol was followed. Results were limited to full-text articles that were published in peer-reviewed journals and printed in English. Additional studies were added after a citation search of included studies. Studies were eligible for inclusion if researchers evaluated youth sport coaches' knowledge, beliefs, contextual perceptions, or all 3 of anterior cruciate ligament injury-prevention training programs.

DATA EXTRACTION

Data charting was performed by 1 author and confirmed by a separate author.

DATA SYNTHESIS

Of the 1194 articles identified, 19 were included in the final sample. Among articles in which researchers assessed knowledge (n = 19), coaches' awareness of the existence and components of injury-prevention training programs was inconsistent. Among articles in which researchers assessed beliefs (n = 19), many coaches had positive attitudes toward injury-prevention training programs, but few believed youth athletes are at a high risk of injury. Among articles in which researchers assessed contextual perceptions (n = 13), many coaches did not feel they had access to information about injury-prevention training programs and cited a lack of time, space, support, and other resources as barriers to implementation.

CONCLUSIONS

Our findings support the need for programs, protocols, and policies to enhance knowledge of and support for youth sport coaches who wish to implement injury-prevention training programs. A gap exists in the research about addressing the needs of youth sport coaches in the United States high school sports setting. The use of multilevel implementation science frameworks (such as the Theoretical Domains Framework) will be beneficial for identifying constructs that affect implementation and developing train-the-trainer programming to meet the needs of individual youth sport coaches.

Evidence-Based Data Models for Return-to-Play Criteria after Anterior Cruciate Ligament Reconstruction

The anterior cruciate ligament (ACL) tear is one of the most common knee injuries in sports that require side-to-side pivoting movements. While the timeline and specific goals during rehabilitation protocols may vary, ACL reconstruction (ACLR) is the preferred procedure necessary to return these athletes to their respective field of play. However, there are no validated guidelines that define a specific timepoint when it is safe for an athlete to return-to-play, as functional movement deficit may be present much longer than six months post ACLR. A retrospective cross-sectional analysis was conducted on 33 subjects that underwent ACLR. As a part of standard of care, each subject completed a movement screening protocol at a singular timepoint during their rehabilitation process. An innovative three-dimensional markerless motion capture system was used to obtain three algorithm-derived biometric variables: mobility, alignment, and readiness. Significant gradual improvements in mobility and readiness were observed throughout a 3–6-month post ACLR procedure period. When examining the data trends, it was obvious that not all patients responded identically to treatment plans provided by clinical professionals. Therefore, the findings of the present study suggest that the decision regarding when it is safe to return to play needs to be determined on an individual basis.

Implementing ACL Injury Prevention in Daily Sports Practice-It's Not Just the Program: Let's Build Together, Involve the Context, and Improve the Content

Although the benefits of current anterior cruciate ligament (ACL) injury prevention programmes have been demonstrated in efficacy studies, they, unfortunately, have had limited public health impact to date. For example, the incidence of ACL injuries continues to rise in adolescent athletes. Raising awareness and educating coaches and athletes is not enough to facilitate the widespread, sustained use of these programmes in the real-world setting. Considering the profound burden of ACL injuries, it is necessary to continue to improve the current ACL injury prevention programmes through co-creation. First, the uptake of the programmes should be optimized by a better appreciation and understanding of the individual, socio-cultural and environmental context (i.e., community). Second, the content of the programmes should be optimized to better reflect the demands of the sport by creating more ownership and increasing motivation (incorporating challenging, sport-specific and fun elements) with the end-users. In addition, implicit motor learning, random practice and differential learning are concepts that should be integrated when practising to obtain the most optimal results when learning or finetuning skills.