ACL injuries in men's professional football: a 15-year prospective study on time trends and return-to-play rates reveals only 65% of players still play at the top level 3 years after ACL rupture

Anterior Cruciate Ligament Injury: Return to Play, Function and Long-Term Considerations

Anterior cruciate ligament tears are common and affect young individuals who participate in jumping and pivoting sports. After injury many individuals undergo ligament reconstruction (ACLR) but do not return to play, suffer recurrent injury and osteoarthritis. Outcome studies show that after ACLR, 81% of individuals return to sports, 65% return to their preinjury level and 55% return to competitive sports. Systematic reviews place the risk of ipsilateral retears at 5.8% and contralateral injuries at 11.8%, with recent reports of over 20% failure rate. Approximately 20% to 50% of patients will have evidence of OA within 10 to 20 yr. Factors important in reducing complications include timing of surgery, individualized return to play protocols, and prevention programs for injury. Further understanding of the factors that increase return to play percentages, reduce the risk of recurrent injury and improve long-term outcomes after ACL injury is needed to reduce the burden of these injuries on society.

Anterior cruciate ligament ruptures in German elite soccer players: Epidemiology, mechanisms, and return to play

BACKGROUND

Anterior cruciate ligament ruptures (ACLRs) are severe sports-related injuries with significant consequences for affected players and teams. This study aims to identify the epidemiology and injury-related lay-off after ACLR in professional male soccer players from the first-division German Bundesliga.

METHODS

Exposure times and incidence of anterior cruciate ligament ruptures were collected during 7.5 consecutive seasons using two media-based registers.

RESULTS

A total of 72 total ACLRs were registered in 66 different players with an incidence of 0.040 per 1000h of exposure (95% CI 0.009-0.12). On average there were 9.6 ACLRs per season and 0.53 per team and season. The mean age of players affected was 24 (standard deviation±3.6) years. The number of ACLRs recorded per season fluctuated during the period observed. Goalkeepers are significantly (P<0.05) less prone to suffer an ACLR compared to outfield players.

CONCLUSIONS

Understanding ACLR loading mechanisms, knowing risk factors for the injury and mean off time after ACLR are essential information for the coach, the medical staff, the elite soccer players, the insurance and team managers. Our results are in accordance with reports based on information from medical team staff. Therefore, our analysis of ACLR based on media sources may serve as an alternative for injury reports in elite soccer. The information of this study may be helpful for the medical staff taking care of professional soccer players and for orthopedic surgeons performing ACL reconstructions in this patient population.

Career Length and Injury Incidence After Anterior Cruciate Ligament Reconstruction in Major League Soccer Players

Background:

Little is known about career length after anterior cruciate ligament (ACL) reconstruction in Major League Soccer (MLS), the top men’s professional soccer league in the United States. Further, it is unspecified whether athletes returning to soccer after ACL reconstruction are at a higher risk for injuries, beyond new knee injuries.

Purpose:

To examine career length and the incidence of lower extremity injuries in MLS athletes after ACL reconstruction in comparison with age-matched controls.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Injuries and athletic exposures (AEs; games and training sessions) were recorded in the HealtheAthlete database, the injury surveillance system of MLS. All athletes who had undergone ACL reconstruction and returned to MLS were identified and age-matched with controls. Multivariate analyses of variance were used to compare career length and percentage of regular/postseason games that athletes started, substituted, or did not play. Generalized linear model regressions were used to examine the injury risk.

Results:

Athletes in the ACL group had shorter careers (1.3 ± 1.3 years) than those in the control group (2.5 ± 1.3 years) (P < .01), but while they were playing, athletes in the ACL group participated in a similar number of AEs as those in the control group (169.9 ± 129.0 vs 171.6 ± 124.9 AEs, respectively; P = .95). Athletes in the ACL group started fewer regular/postseason games (36.7% ± 34.3% vs 60.1% ± 33.8%, respectively; P < .01) and did not play in more regular/postseason games (47.4% ± 35.5% vs 31.0% ± 34.4%, respectively; P = .03) compared with those in the control group. The ACL group was not at a significantly greater risk for lower extremity injuries compared with the control group (relative risk, 0.87; 95% CI, 0.55-1.37).

Conclusion:

Although MLS athletes after ACL reconstruction are not at a greater risk for lower extremity injuries, this study suggests that they are not utilized in regular/postseason games as frequently and that their careers in MLS are shorter than age-matched controls. Further research is necessary to elucidate reasons for these athletes’ shortened MLS careers. This study supports the view of return to sport not as a single time point but as a continuum from return to participation to return to play and return to performance.

Severe musculoskeletal time-loss injuries and symptoms of common mental disorders in professional soccer: a longitudinal analysis of 12-month follow-up data

PURPOSE

Psychological factors have shown to be predictors of injury in professional football. However, it seems that this is a two-way relationship, as severe musculoskeletal time-loss injuries have shown to be associated with the onset of symptoms of common mental disorders (CMD). There is no longitudinal study performed exploring this interaction between symptoms of CMD and injuries. The purpose of this study was to explore the interaction between severe musculoskeletal time-loss injuries and symptoms of CMD in professional football players over a 12-month period.

METHODS

Players were recruited by their national players' unions in five European countries. Symptoms of CMD included in the study were related to distress, anxiety/depression, sleep disturbance and adverse alcohol use.

RESULTS

A total of 384 professional football players were enrolled in the study, of whom 262 (68%) completed the 12-month follow-up period. The mean age of the participants at baseline was 27 ± 5 years, and they had played professional football for 8 ± 5 years on average. Symptoms of CMD at baseline were not associated with the onset of severe musculoskeletal time-loss injuries during the follow-up period with relative risks (and 95% CI) ranging from 0.6 (0.3-1.0) to 1.0 (0.5-2.2). In contrast, severe musculoskeletal time-loss injuries reported at baseline were associated with the onset of symptoms of CMD during the follow-up period with relative risks ranging from 1.8 (0.8-3.7) to 6.9 (4.0-11.9).

CONCLUSION

No relationship was found between symptoms of CMD and the onset of severe musculoskeletal time-loss injuries. However, professional football players who suffered from severe musculoskeletal time-loss injuries are likely to develop subsequent symptoms of CMD. This study emphasizes the need for an interdisciplinary medical approach, which not only focuses on the physical but also on the mental health of professional football players. An early identification of players at risk of symptoms of CMD, such as those suffering from severe musculoskeletal injuries, creates the opportunity for an interdisciplinary clinical medical team to treat the players timely and adequately.

LEVEL OF EVIDENCE

Prospective cohort study, Level II.

Concomitant injuries may not reduce the likelihood of achieving symmetrical muscle function one year after anterior cruciate ligament reconstruction: a prospective observational study based on 263 patients

PURPOSE

A better understanding of patient characteristics and the way common concomitant injuries affect the recovery of muscle function after surgery should help providers to treat patients with anterior cruciate ligament (ACL) injuries. The aim of this study was to determine whether patient characteristics, concomitant injuries and graft choice at ACL reconstruction were associated with symmetrical knee muscle function at one year. The hypothesis was that the presence of concomitant injuries would negatively influence the opportunity to achieve symmetrical knee function at the one-year follow-up.

METHODS

Data was extracted from the Swedish National Knee Ligament Register and a rehabilitation outcome register between August 2012 and December 2016. The patients had been evaluated with a battery of tests comprising knee extension and flexion strength, vertical jump, hop for distance and the side-hop test one year after ACL reconstruction. Univariable and multivariable logistic regression analyses were performed with achieving a limb symmetry index (LSI) of ≥ 90% in all tests of muscle function as primary outcome.

RESULTS

A total of 263 patients with a mean age of 26.7 ± 10.3 years were included in the study (47% females). No patient demographic or intra-operative predictors were found to be significant when attempting to predict the achievement of a symmetrical muscle function. Lateral meniscus injury and a patellar tendon autograft reduced the odds of achieving an LSI of ≥ 90% in knee extension strength, OR = 0.49 [(95% CI 0.25-0.97), p = 0.039] and OR = 0.30 [(95% CI 0.14-0.67), p = 0.0033] respectively. In addition, reduced odds of recovering knee extension strength were found in older patients, OR = 0.76 [(95% CI 0.60-0.98), p = 0.034]. A higher pre-injury level of physical activity increased the odds of recovering knee flexion strength, OR = 1.14 [(95% CI 1.01-1.29), p = 0.037].

CONCLUSION

Intra-operatively identified concomitant injuries or graft choice did not affect the likelihood of recovering symmetrical performance in five different tests of muscle function one year after ACL reconstruction. However, fewer than one in four patients achieved an LSI of ≥ 90% in all tests.

LEVEL OF EVIDENCE

Prospective observational study: Level 2.

Automated Assessment of Dynamic Knee Valgus and Risk of Knee Injury During the Single Leg Squat

Many clinical assessment protocols of the lower limb rely on the evaluation of functional movement tests such as the single leg squat (SLS), which are often assessed visually. Visual assessment is subjective and depends on the experience of the clinician. In this paper, an inertial measurement unit (IMU)-based method for automated assessment of squat quality is proposed to provide clinicians with a quantitative measure of SLS performance. A set of three IMUs was used to estimate the joint angles, velocities, and accelerations of the squatting leg. Statistical time domain features were generated from these measurements. The most informative features were used for classifier training. A data set of SLS performed by healthy participants was collected and labeled by three expert clinical raters using two different labeling criteria: "observed amount of knee valgus" and "overall risk of injury". The results showed that both flexion at the hip and knee, as well as hip and ankle internal rotation are discriminative features, and that participants with "poor" squats bend the hip and knee less than those with better squat performance. Furthermore, improved classification performance is achieved for females by training separate classifiers stratified by gender. Classification results showed excellent accuracy, 95.7 % for classifying squat quality as "poor" or "good" and 94.6% for differentiating between high and no risk of injury.

Translation, cross-adaptation and measurement properties of the Brazilian version of the ACL-RSI Scale and ACL-QoL Questionnaire in patients with anterior cruciate ligament reconstruction

•

The Brazilian versions of ACL-RSI and ACL-QoL were translated and culturally adapted.

•

The Brazilian ACL-RSI and ACL-QoL demonstrated adequate measurement properties.

•

The Brazilian ACL-RSI and ACLQoL are useful outcomes for clinical and research.

Background

Scales to assess the quality of life and return-to-sport after reconstruction of the anterior cruciate ligament (ACL) may help the clinical decision-making process.

Objective

To cross-culturally adapt and determine the validity of the Brazilian versions of the Anterior Cruciate Ligament Return to Sport after Injury (ACL-RSI) and the Quality of Life Questionnaire (ACL-QoL).

Methods

The process of translation and cross-cultural adaptation followed the recommendations of international guidelines. One hundred participants filled out the Brazilian versions of these instruments, the Tampa Scale for Kinesiophobia (TSK), the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, and the 36-Item Short Form Health Survey (SF-36). The measurement properties of reliability, internal consistency and construct validity were measured.

Results

The ACL-RSI and the ACL-QoL were successfully translated and cross-culturally adapted. Both questionnaires showed good test–retest reliability (ICC_2,1 = 0.78, 95% CI = 0.67–0.85 for the ACL-RSI; and ICC_2,1 = 0.84, 95% CI = 0.76–0.90 for the ACL-QoL) and good internal consistency (Cronbach's alpha = 0.87 for the ACL-RSI; and Cronbach's alpha = 0.96 for the ACL-QoL). A reasonable correlation was found between both questionnaires and the TSK, and a low to reasonable correlation was found between the questionnaires and the SF-36 in terms of validity. Compared to the IKDC Subjective Knee Evaluation Form, the ACL-RSI had a reasonable correlation and the ACL-QoL had a good correlation.

Conclusion

The Brazilian versions of the ACL-RSI and the ACL-QoL have adequate measurement properties and may be used in assessing Brazilians after ACL reconstruction.

ACL Return to Sport Guidelines and Criteria

PURPOSE OF REVIEW

Because of the epidemiological incidence of anterior cruciate ligament (ACL) injuries, the high reinjury rates that occur when returning back to sports, the actual number of patients that return to the same premorbid level of competition, the high incidence of osteoarthritis at 5-10-year follow-ups, and the effects on the long-term health of the knee and the quality of life for the patient, individualizing the return to sports after ACL reconstruction (ACL-R) is critical. However, one of the challenging but unsolved dilemmas is what criteria and clinical decision making should be used to return an athlete back to sports following an ACL-R. This article describes an example of a functional testing algorithm (FTA) as one method for clinical decision making based on quantitative and qualitative testing and assessment utilized to make informed decisions to return an athlete to their sports safely and without compromised performance. The methods were a review of the best current evidence to support a FTA.

RECENT FINDINGS

In order to evaluate all the complicated domains of the clinical decision making for individualizing the return to sports after ACL-R, numerous assessments need to be performed including the biopsychosocial concepts, impairment testing, strength and power testing, functional testing, and patient-reported outcomes (PROs). The optimum criteria to use for individualizing the return to sports after ACL-R remain elusive. However, since this decision needs to be made on a regular basis with the safety and performance factors of the patient involved, this FTA provides one method of quantitatively and qualitatively making the decisions. Admittedly, there is no predictive validity of this system, but it does provide practical guidelines to facilitate the clinical decision making process for return to sports. The clinical decision to return an athlete back into competition has significant implications ranging from the safety of the athlete, to performance factors and actual litigation issues. By using a multifactorial FTA, such as the one described, provides quantitative and qualitatively criteria to make an informed decision in the best interests of the athlete.

Strategies for injury prevention in Brazilian football: Perceptions of physiotherapists and practices of premier league teams

OBJECTIVES

To describe the physiotherapists perceptions and the current practices for injury prevention in elite football (soccer) clubs in Brazil.

DESIGN

Cross-sectional study.

SETTING

Group of Science in Sports & Exercise, Federal University of Healthy Sciences of Porto Alegre (Brazil).

PARTICIPANTS

16 of the 20 football clubs involved in the Brazilian premier league 2015.

MAIN OUTCOME MEASURES

Physiotherapists answered a structured questionnaire.

RESULTS

Most physiotherapists (∼88%) were active in design, testing and application of prevention programs. Previous injury, muscle imbalance, fatigue, hydration, fitness, diet, sleep/rest and age were considered "very important" or "important" injury risk factors by all respondents. The methods most commonly used to detect athletes' injury risk were: monitoring of biochemical markers (100% of teams), isokinetic dynamometry (81%), questionnaires (75%), functional movement screen (56%), fleximetry (56%) and horizontal jump tests (50%). All clubs used strength training, functional training, core exercises and balance/proprioception exercises in their injury prevention program; and Nordic hamstring exercise and other eccentric exercises were used by 94% of clubs. "FIFA 11+" prevention program was adapted by 88% of clubs.

CONCLUSION

Physiotherapists perceptions and current practices of injury prevention within Brazilian elite football clubs were similar to those employed in developed countries. There remains a gap between clinical practice and scientific evidence in high performance football.

Performance: Bridging the Gap After ACL Surgery

PURPOSE OF REVIEW

The purpose of this paper is to identify strategies for a successful transition to sports in patients following rehabilitation for ACL reconstruction surgery (ACLR).

RECENT FINDINGS

Recent research continues to demonstrate a relatively low rate of return to previous level of play among athletes following ACLR combined with a significant risk of injury to either the ipsi or the contralateral ACL. Recent research also demonstrates a growing use of a varied battery of assessments to determine readiness to return to sport as well as a lack of consensus on the ideal rehabilitation program, the criteria for clearance for return to play (both in time from surgery and functional milestones), and the nature of a conditioning program designed specifically for transitioning the cleared athlete back to competition. Due to the lack of consensus and consistency regarding rehabilitation protocols and criteria for clearance to play after ACLR, deficits in strength, neuromuscular control, and psychological readiness may exist in "cleared" athletes. These deficits may not only negatively impact sports performance but also raise the risk of re-injury. Programs designed to successfully return an athlete to previous level of play should include not only strength and conditioning aimed at restoring fitness that was compromised as a result of the injury but also include attention to psychological readiness and address deficits in neuromuscular control. Problems that exist following ACLR cannot be solved by one professional; successful rehabilitation and return to play require a coordinated effort among the surgeon, physical therapist, athletic trainer, and fitness professional. Future research is needed to determine the optimal strategy to restore the neuromuscular control, functional strength, and psychological readiness necessary for a successful return to competition following ACLR.

Factors Associated With Improved Function and Maintenance of Sports Activities at 5 to 10 Years After Autologous Hamstring ACL Reconstruction in Young Men

Background:

There are limited data regarding associated factors of return to sports activities at more than 5 years after anterior cruciate ligament (ACL) reconstruction.

Purpose:

To test interrelationships between patient characteristics, concomitant articular lesions, graft laxity, and maintenance of sports activities at 5 to 10 years after ACL reconstruction. It was hypothesized that at 5 to 10 years after the operation in young adult men, maintenance of greater activity level and better knee function would be associated with greater preinjury activity level, younger age at reconstruction, absence of concomitant articular lesions, and minimal graft laxity at follow-up.

Study Design:

Case series; Level of evidence, 4.

Methods:

One hundred six men with autologous hamstring ACL reconstruction between the ages of 18 and 35 years were reviewed at 5 to 10 years after surgery. Excluded patients had contralateral ACL tear, revision reconstruction, or another injury impairing function. Fifty-five patients were eligible and available for follow-up. Independent variables included preinjury Tegner score, time interval from injury to surgery, smoking status, age, articular lesions, KT side-to-side difference, and pivot-shift grade. Main outcome measures were Tegner activity level, International Knee Documentation Committee (IKDC) subjective score, and Knee injury and Osteoarthritis Outcome Scale (KOOS) score at 5 to 10 years after surgery.

Results:

Greater Tegner activity level at follow-up was associated in a regression model with greater preinjury Tegner activity level (correlation coefficient, 0.423; P = .01), lower KT difference (correlation coefficient, –0.278; P = .04), and negative pivot shift (correlation coefficient, –0.277; P = .05). Younger age at operation predicted return to greater Tegner activity level in a univariate analysis (correlation coefficient, –0.266; P = .05) but not in a regression model (not significant). Chondral lesions at surgery predicted lower IKDC subjective scores (71.4 ± 14.3 vs 84.1 ± 11.5; P < .01) and KOOS scores but did not affect maintenance of sports activities.

Conclusion:

At 5 to 10 years after autologous hamstring ACL reconstruction in young men, predictors of greater sports activity level are primarily high preinjury activity level and reestablishment of knee laxity. Younger age at operation and moderate chondral lesions have lower impact in this respect.

Anterior cruciate ligament injury/reinjury in alpine ski racing: a narrative review

The purpose of the present review was to: 1) provide an overview of the current understanding on the epidemiology, etiology, risk factors, and prevention methods for anterior cruciate ligament (ACL) injury in alpine ski racing; and 2) provide an overview of what is known pertaining to ACL reinjury and return to sport after ACL injury in alpine ski racing. Given that most of the scientific studies on ACL injuries in alpine ski racing have been descriptive, and that very few studies contributed higher level scientific evidence, a nonsystematic narrative review was employed. Three scholarly databases were searched for articles on ACL injury or knee injury in alpine ski racing. Studies were classified according to their relevance in relation to epidemiology, etiology, risk factors, and return to sport/reinjury prevention. Alpine ski racers (skiers) were found to be at high risk for knee injuries, and ACL tears were the most frequent diagnosis. Three primary ACL injury mechanism were identified that involved tibial internal rotation and anteriorly directed shear forces from ski equipment and the environment. While trunk muscle strength imbalance and genetics were found to be predictive of ACL injuries in development-level skiers, there was limited scientific data on ACL injury risk factors among elite skiers. Based on expert opinion, research on injury risk factors should focus on equipment design, course settings/speed, and athlete factors (eg, fitness). While skiers seem to make a successful recovery following ACL injury, there may be persistent neuromuscular deficits. Future research efforts should be directed toward prospective studies on ACL injury/reinjury prevention in both male and female skiers and toward the effects of knee injury on long-term health outcomes, such as the early development of osteoarthritis. International collaborations may be necessary to generate sufficient statistical power for ACL injury/reinjury prevention research in alpine ski racing.

Vertical stiffness is not related to anterior cruciate ligament elongation in professional rugby union players

Background

Novel research surrounding anterior cruciate ligament (ACL) injury is necessary because ACL injury rates have remained unchanged for several decades. An area of ACL risk mitigation which has not been well researched relates to vertical stiffness. The relationship between increased vertical stiffness and increased ground reaction force suggests that vertical stiffness may be related to ACL injury risk. However, given that increased dynamic knee joint stability has been shown to be associated with vertical stiffness, it is possible that modification of vertical stiffness could help to protect against injury. We aimed to determine whether vertical stiffness is related to measures known to load, or which represent loading of, the ACL.

Methods

This was a cross-sectional observational study of 11 professional Australian rugby players. Knee kinematics and ACL elongation were measured from a 4-dimensional model of a hopping task which simulated the change of direction manoeuvre typically observed when non-contact ACL injury occurs. The model was generated from a CT scan of the participant's knee registered frame by frame to fluoroscopy images of the hopping task. Vertical stiffness was calculated from force plate data.

Results

There was no association found between vertical stiffness and anterior tibial translation (ATT) or ACL elongation (r=−0.05; p=0.89, and r=−0.07; p=0.83, respectively). ATT was related to ACL elongation (r=0.93; p=0.0001).

Conclusions

Vertical stiffness was not associated with ACL loading in this cohort of elite rugby players but a novel method for measuring ACL elongation in vivo was found to have good construct validity.

Measurement of movement patterns to enhance ACL injury prevention - A dead end?

Vertical drop jump has been suggested to be an effective movement screening task for ACL injury risk, but recent studies have questioned the ability of such tasks to accurately identify players with increased risk of injury. In this paper, we discuss the usefulness of movement screening tests from an injury prevention perspective.