Anterior cruciate ligament injury after more than 20 years. II. Concentric and eccentric knee muscle strength

The long‐term consequences on knee muscle strength some decades after rupture of the anterior cruciate ligament (ACL) are not established. The aims of our study were to examine peak torque more than 20 years after ACL injury and to compare their knee muscle strength to that of healthy controls. We tested 70 individuals with unilateral ACL injury 23 ± 2 years after injury, whereof 33 (21 men) were treated with physiotherapy in combination with ACL reconstruction (ACL_R) and 37 (23 men) with physiotherapy alone (ACL_PT). These were compared with 33 age‐ and gender‐matched controls (21 men). A Kin‐Com^® dynamometer (90°/s) was used to measure peak torque in knee flexion and extension in both concentric and eccentric contractions. Knee extension peak torque, concentric and eccentric, was ～10% lower for the injured leg compared with the non‐injured leg for both ACL_R (P < 0.001; P < 0.001) and ACL_PT (P = 0.007; P = 0.002). The ACL_PT group also showed reduced eccentric knee flexion torque of the injured leg (P = 0.008). The strength of the non‐injured leg in both ACL groups was equal to that of controls. No difference was seen for those with no‐or‐low degree of knee osteoarthritis compared to those with moderate‐to‐high degree of osteoarthritis. ACL injury may lead to a persistent reduction of peak torque in the injured leg, which needs to be considered across the lifespan.     

Anterior cruciate ligament injury after more than 20 years: I. Physical activity level and knee function

Little is known about physical activity level and knee function including jump capacity and fear of movement/reinjury more than 20 years after injury of the anterior cruciate ligament (ACL). Seventy persons with unilateral ACL injury participated (23 ± 2 years post‐injury): 33 treated with physiotherapy in combination with surgical reconstruction (ACL_R), and 37 treated with physiotherapy alone (ACL_PT). These were compared with 33 age‐ and gender‐matched controls. Assessment included knee‐specific and general physical activity level [Tegner activity scale, International Physical Activity Questionnaire (IPAQ)], knee function [Lysholm score, Knee injury and Osteoarthritis Outcome Score (KOOS)], jump capacity (one‐leg hop, vertical jump, side hops), and fear of movement/reinjury [Tampa Scale for Kinesiophobia (TSK)]. Outcomes were related to degree of osteoarthritis (OA). ACL‐injured had lower Lysholm, KOOS, and Tegner scores than controls (P < 0.001), while IPAQ score was similar. ACL‐injured demonstrated inferior jump capacity in injured compared with noninjured leg (6–25%, P < 0.001–P = 0.010 in the different jumps), while noninjured leg had equal jump capacity as controls. ACL groups scored 33 ± 7 and 32 ± 7 of 68 on TSK. Lower scores on Lysholm and KOOS symptom were seen for persons with moderate‐to‐high OA than for no‐or‐low OA, while there were no differences for physical activity and jump capacity. Regardless of treatment, there are still negative knee‐related effects of ACL injury more than 20 years later.     

Coach‐led prevention programs are effective in reducing anterior cruciate ligament injury risk in female athletes: A number‐needed‐to‐treat analysis

The purpose of this study was to determine whether the effectiveness of an anterior cruciate ligament (ACL) prevention program is impacted by the individual(s) directing the program. A number‐needed‐to‐treat analysis compared the effectiveness of injury prevention measures when either directed by a coach or a mixed leadership group consisting of coach and healthcare providers. Eleven studies were included for analysis. Number‐needed‐to‐treat and relative risk reduction (RRR) were calculated for each study and data sets were pooled based on the intervention leader. Quality of evidence was determined by assessing individual studies (PEDro score =4.55±1.97, range=2‐7), applying the Oxford Centre for Evidence‐Based Medicine Levels of Evidence (CEBM=2a), and the Strength of Recommendation Taxonomy (SORT=Level B). The mixed leadership group studies' RRR=48.2% (95% confidence interval (CI)=22‐65) and a number‐needed‐to‐benefit of 120 (CI=73‐303) while the coach‐led group's RRR=58.4% (CI=40‐71) and a number‐needed‐to‐benefit=133 (CI=96‐217). These results demonstrate that a coach‐led ACL injury prevention program approach is as effective as a mixed group leadership approach. Coach‐led prevention programs can be more widely implemented; however, it is imperative to ensure adequate training is in place prior to implementation of such intervention.     

Anterior cruciate ligament volume: analysis of gender differences

In this study, gender differences in the anterior cruciate ligament (ACL) were assessed with high resolution MRI. Using a quadrature extremity coil at 1.5T, volumes of the separate bundles of the ACL (anteromedial [AMB] and posterolateral [PLB]) were measured with shaded surface three-dimensional (3D) reconstruction in 63 knees (33 male, 30 female). Bundle volumes were measured from consecutive fat-suppressed fast spin-echo proton-density coronal MR images and intraobserver reproducibility was recorded. The data were divided into subgroups based on gender, age, height, weight, and body mass index (BMI) for statistical analysis. Results of the study revealed the mean ACL volume to be significantly different for males (1.07 cc) and females (0.77 cc) (P = 0.0025), yet when adjusting for body height differences, these were no longer significantly different. Mean AMB volume was smaller than the PLB volume for females (0.33 cc vs. 0.44 cc; P < 0.0001) and males (0.49 cc vs. 0.58 cc; P < 0.0001). Correlation coefficients were highest for height (r = 0.597) and weight (r = 0.5371) and regression analysis revealed height to be the most significant factor affecting ACL volume. Intraobserver measurements were reproducible (r = 0.90). From this data, we conclude that gender differences in ACL volume are present, but may be accounted for by height differences between males and females.     

Knee function among elite handball and football players 1‐6 years after anterior cruciate ligament injury

The aim of the study was to describe objective and self‐reported knee function for athletes who have returned to elite handball and football play after an ACL injury, comparing these to non‐injured players at the same level. A total of 414 handball and 444 football players completed baseline tests from 2007 through 2014, examining lower extremity strength, dynamic balance, knee laxity, and knee function (KOOS questionnaire). Measures were compared between injured and non‐injured legs and between injured legs and legs of controls. Eighty (9.3%) of the 858 players reported a previous ACL injury, 1‐6 years post‐injury (3.5±2.5 years), 49 handball (61.3%) and 31 football players (38.7%). We found no difference in strength or dynamic balance between previously ACL‐injured (N=80) and non‐injured players legs (N=1556). However, lower quadriceps (6.3%, 95% CI: 3.2‐9.2) and hamstrings muscle strength (6.1%, 95% CI: 3.3‐8.1) were observed in previously ACL‐injured legs compared to the non‐injured contralateral side (N=80). ACL‐injured knees displayed greater joint laxity than the contralateral knee (N=80, 17%, 95% CI: 8‐26) and healthy knees (N=1556, 23%, 95% CI: 14‐33). KOOS scores were significantly lower for injured knees compared to knees of non‐injured players. ACL‐injured players who have successfully returned to elite sport have comparable strength and balance measures as their non‐injured teammates. Subjective perception of knee function is strongly affected by injury history, with clinically relevant lower scores for the KOOS subscores Pain, Function, Sport, and Quality Of Life.     

Asymmetries in joint work during multi‐joint movement after anterior cruciate ligament reconstruction: A pilot study

After anterior cruciate ligament reconstruction (ACL‐R), many studies have reported a deficit of performance on the injured leg during multi‐joint tasks. However, the total mechanical joint work (W_Total), parameter best related to the vertical displacement of the body mass center during vertical jumping, has not yet been studied. The aim of this research was to compare asymmetries between ACL‐R subjects and healthy matched subjects, through the analysis of the kinematics and kinetics during a single‐leg squat jump. Asymmetries are defined by the Limb Symmetry Index (LSI). A greater LSI was observed for W_Total in the ACL‐R group than in the healthy group. There was no difference in LSI for knee joint work between the two groups, while the LSI for hip and ankle joint work was significantly larger in the ACL‐R group. This was explained by greater LSI for the hip and ankle joint range of motion in the ACL‐R group than in the healthy group. After ACL‐R, patients exhibited greater asymmetries than healthy subjects during single‐leg squat jump. Physiotherapists should focus on quality execution of multi‐joint movement, especially on hip and ankle joints range of motion in order to reduce asymmetries and to improve vertical jumping performance.     

Motives for sports participation as predictions of self‐reported outcomes after anterior cruciate ligament injury of the knee

Aim of the study was to access how individual's motives for participation in sports impact on self‐reported outcomes 2 years after an anterior cruciate ligament injury. Based on a longitudinal cohort study, this secondary analysis present data from the Knee Anterior Cruciate Ligament, Nonsurgical versus Surgical Treatment (KANON) study, a randomized controlled trial. At baseline, 121 patients recorded in an initial questionnaire that their motives for sports participation fell into four categories: achievement, health, social integration, or fun and well‐being. These four categories were used as variables in the analyses. All 121 subjects completed the 2‐year follow‐up. The largest improvement was seen in the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale sports and recreation function, with an effect size of 2.43. KOOS sports and recreation function was also the subscale score best predicted by the motives for sports participation. Baseline motives achievement and fun and well‐being predicted worse levels of pain and function 2 years after the injury, even after adjusting for age, gender, treatment and baseline scores. Psychological aspects, such as motives for participation in sport, can be factors in predicting of patient‐reported outcomes 2 years after injury. Evaluating motives for sports participation may help predict the outcome 2 years after ACL injury.     

Assessment of anterior cruciate ligament reconstruction using 3D ultrashort echo‐time MR imaging

This work demonstrates the potential of ultrashort TE (UTE) imaging for visualizing graft material and fixation elements after surgical repair of soft tissue trauma such as ligament or meniscal injury. Three asymptomatic patients with anterior cruciate ligament (ACL) reconstruction using different graft fixation methods were imaged at 1.5T using a 3D UTE sequence. Conventional multislice turbo spin‐echo (TSE) measurements were performed for comparison. 3D UTE imaging yields high signal from tendon graft material at isotropic spatial resolution, thus facilitating direct positive contrast graft visualization. Furthermore, metal and biopolymer graft fixation elements are clearly depicted due to the high contrast between the signal‐void implants and the graft material. Thus, the ability of UTE MRI to visualize short‐T₂ tissues such as tendons, ligaments, or tendon grafts can provide additional information about the status of the graft and its fixation in the situation after cruciate ligament repair. UTE MRI can therefore potentially support diagnosis when problems occur or persist after surgical procedures involving short‐T₂ tissues and implants. J. Magn. Reson. Imaging 2009;29:443–448. © 2009 Wiley‐Liss, Inc.     

Landing strategies focusing on the control of tibial rotation in the initial contact period of one‐leg forward hops

Anterior cruciate ligament (ACL) reconstruction (ACLR) surgeries successfully restore anterior tibial translation but not tibial rotation. This study aimed to explore landing strategies focusing on the control of tibial rotation at landing when the ACL is most vulnerable. Three groups of male subjects (50 ACLRs, 26 basketball players, and 31 controls) participated in one‐leg forward hop tests for determining the tibial rotatory landing strategies adopted during the initial landing phase. The differences in knee kinematics and muscle activities between internal and external tibial rotatory (ITR, ETR) landing strategies were examined. A higher proportion of basketball players (34.6%) were found to adopt ITR strategies (controls: 6.5%), exhibiting significantly greater hopping distance and knee strength. After adjusting for hopping distance, subjects adopting ITR strategies were found to hop faster with straighter knees at foot contact and with greater ITR and less knee adduction angular displacement during the initial landing phase. However, significantly greater angular displacement in knee flexion, greater medial hamstring activities, and greater co‐contraction index of hamstrings and medial knee muscles were also found during initial landing. Our results support the importance of the recruitments of medial hamstrings or the local co‐contraction in assisting the rotatory control of the knee during initial landing for avoiding ACL injuries.     

Clinical outcomes of double‐ vs single‐bundle anterior cruciate ligament reconstruction: A systematic review of randomized control trials

Clinical outcomes of anterior cruciate ligament (ACL) reconstruction with double‐bundle and single‐bundle techniques are still controversial. We therefore performed a systematic review to compare postoperative outcomes between the two techniques. Randomized control trials comparing the outcomes between the two techniques were identified from Medline and EMBASE since inception to April 27, 2011. Data were independently extracted by two reviewers. Thirteen of 318 studies were eligible; 9, 11, 7, and 8 studies were pooled for rotation, translation, function, and complication outcomes, respectively. The double‐bundle technique was approximately four times (95% CI: 2.65, 11.99) and two times (95% CI: 1.16, 5.21) more likely to show a normal pivot shift and normal International Knee Documentation Committee (IKDC) grading compared with the single‐bundle technique. However, there were nonsignificant differences in KT grading (OR = 1.66, 95% CI: 0.77, 3.82), IKDC score (0.29, 95% CI: ?1.17, 1.75), Lysholm knee score (?0.87, 95% CI: ?2.66, 0.93), Tegner activity score (0.37, 95% CI: ?0.05, 0.79), and complications (OR = 1.11, 95% CI: 0.48, 2.57). Heterogeneity was present in some outcomes but there was no evidence of publication bias for any outcome. The double‐bundle may be better than the single‐bundle ACL reconstruction technique in rotational stability but not for function, translation, and complications.     

Kinematic analysis of pressing situations in female collegiate football games: New insight into anterior cruciate ligament injury causation

The most common events during which anterior cruciate ligament (ACL) injuries occur in football are pressing situations. This study aimed to describe the knee and hip joint kinematics during pressing situations in football games to identify kinematic patterns in actions with a high risk for ACL injuries. We filmed 5 female collegiate football matches and identified 66 pressing situations. Five situations with a large distance between the trunk and foot placements in the sagittal plane were analyzed using a model‐based image‐matching technique. The mean knee flexion angle at initial contact (IC) was 13° (range, 8°‐28°) and increased by 11° (95% confidence interval [CI], 3°‐14°) at 40 ms after IC. As for knee adduction and rotation angles, the knee positions were close to neutral at IC, and only minor knee angular changes occurred later in the sequences. The mean hip flexion was 25° (range, 8°‐43°) at IC and increased by 22° (95% CI, 11°‐32°) after 100 ms. The hip was also externally rotated by 7° (range, −19° to 3°) at IC, and gradually rotated internally, reaching 10° of internal rotation (range, −5° to 27°) at 100 ms after IC. This study suggests that the observed knee valgus, internal hip and knee rotation, and static hip flexion previously reported in non‐contact ACL injury events are unique to injury situations. In contrast, neither rapid knee valgus nor increased internal rotation was seen in non‐injury pressing maneuvers.     

Effects of fasted vs fed‐state exercise on performance and post‐exercise metabolism: A systematic review and meta‐analysis

The effects of nutrition on exercise metabolism and performance remain an important topic among sports scientists, clinical, and athletic populations. Recently, fasted exercise has garnered interest as a beneficial stimulus which induces superior metabolic adaptations to fed exercise in key peripheral tissues. Conversely, pre‐exercise feeding augments exercise performance compared with fasting conditions. Given these seemingly divergent effects on performance and metabolism, an appraisal of the literature is warranted. This review determined the effects of fasting vs pre‐exercise feeding on continuous aerobic and anaerobic or intermittent exercise performance, and post‐exercise metabolic adaptations. A search was performed using the MEDLINE and PubMed search engines. The literature search identified 46 studies meeting the relevant inclusion criteria. The Delphi list was used to assess study quality. A meta‐analysis and meta‐regression were performed where appropriate. Findings indicated that pre‐exercise feeding enhanced prolonged (P  = .012), but not shorter duration aerobic exercise performance (P  = .687). Fasted exercise increased post‐exercise circulating FFAs (P  = .023) compared to fed exercise. It is evidenced that pre‐exercise feeding blunted signaling in skeletal muscle and adipose tissue implicated in regulating components of metabolism, including mitochondrial adaptation and substrate utilization. This review's findings support the hypothesis that the fasted and fed conditions can divergently influence exercise metabolism and performance. Pre‐exercise feeding bolsters prolonged aerobic performance, while seminal evidence highlights potential beneficial metabolic adaptations that fasted exercise may induce in peripheral tissues. However, further research is required to fully elucidate the acute and chronic physiological adaptations to fasted vs fed exercise.     

A meta‐analysis of meta‐analyses of the effectiveness of FIFA injury prevention programs in soccer

FIFA has a Medical and Research Centre (F‐MARC) which has designed a comprehensive program targeting muscle strength, kinesthetic awareness, and neuromuscular control during static and dynamic movements to decrease injury risk for soccer players. A number of meta‐analyses now exist on how effective FIFA's programs to prevent and reduce injury actually are, with various degrees of injury reduction reported. This research aimed to carry out a systematic review and to meta‐analyse the existing meta‐analyses so that a conclusion can be drawn on how effective the injury programs are. Relevant studies were identified by searching five databases for the period January 1990 till 1 July 2018. Results of each meta‐analysis were combined together using risk ratios (RR) in a summary meta‐analysis. QUOROM checklist and AMSTAR 2 assessment were used to assess the quality of reporting and methodology in the meta‐analyses. Four meta‐analyses met the inclusion criteria covering fifteen primary studies. All four meta‐analyses scored quite highly on QUOROM, but two were rated by AMSTAR 2 as moderate quality, and two were found to be of critically low quality. An overall risk reduction in 34% (RR = 0.66 [0.60‐0.73]) for all injuries and a reduction in 29% (RR = 0.71 [0.63‐0.81]) for injuries to the lower limbs were revealed by this meta‐analysis of meta‐analyses. Combining every previous meta‐analysis into a single source in this paper produced decisive evidence that the risk of injuries while playing soccer is reduced as a result of FIFA's injury prevention programs.     

Myoinositol content in the human brain is modified by transcranial direct current stimulation in a matter of minutes: A 1H‐MRS study

Brain content of myoinositol (mI) has been shown to be altered in several neuropsychiatric conditions. Likewise, various forms of electric currents have been applied to the human brain for therapeutic purposes in neuropsychiatric diseases. In this study we aimed to depict the effects of low‐power transcranial direct current stimulation (tDCS) on brain mI by proton magnetic resonance spectroscopy (¹H‐MRS). We studied two groups of five healthy subjects by ¹H‐MRS: the first group was studied before and after both anodal and sham (placebo) tDCS over the right frontal lobe, and the second group was studied at the same intervals without undergoing either sham or anodal tDCS. Anodal tDCS induced a significant increase of mI content at 30 min after stimulation offset (141.5 ± 16.7%, P < 0.001) below the stimulating electrode but not in distant regions, such as the visual cortex, whereas sham tDCS failed to induce changes in mI. Neither N‐acetyl‐aspartate (NAA) nor the other metabolite contents changed after anodal or sham stimulation. ¹H‐MRS represents a powerful tool to follow the regional effects of tDCS on brain mI and, possibly, on the related phosphoinositide system. Magn Reson Med 60:782–789, 2008. © 2008 Wiley‐Liss, Inc.     

Posterior tibial slope measurement on lateral knee radiographs as a risk factor of anterior cruciate ligament injury: A cross-sectional study

Introduction

The posterior tibial slope (PTS) is believed to be a risk factor for anterior cruciate ligament (ACL) injury. The aim of this study was to reveal the differences in terms of PTS measurements on lateral knee radiographs between ruptured and non-injured cases as well as between males and females in regard to ACL alignment.

Predictors of in‐school and out‐of‐school sport injury prevention: A test of the trans‐contextual model

The current study aimed to predict secondary school students’ motivation toward sport injury prevention in “in‐school” and “out‐of‐school” contexts, and their sport injury prevention behavior at 3‐month follow‐up using the trans‐contextual model (TCM). Hong Kong secondary school students (N = 1566; mean age = 13.34 years, range = 11 to 19; female = 49.42%) were recruited. Participants were asked to complete a survey comprising previously validated scales measuring TCM constructs at baseline and a measure of sport injury prevention behavior at follow‐up three months later. Structural equation modeling (SEM) was used to examine the hypothesized paths among TCM constructs. A SEM specifying hypothesized paths among TCM variables showed acceptable fit with the data (χ²(29) = 418.55, CFI = .93, TLI = .90, and RMSEA = .09, 90% CI [.09, .10], and SRMR = .05). Findings supported tenets of the TCM: the effects of perceived autonomy support from PE teachers on in‐school autonomous motivation toward injury prevention, the trans‐contextual relationship between students' “in‐school” and “out‐of‐school” autonomous motivation toward injury prevention, and the effects of autonomous motivation toward injury prevention on social cognitive variables and subsequent sport injury prevention behaviors. Results supported the tenets proposed within the TCM in predicting students' “in‐school” and “out‐of‐school” autonomous motivation toward sport injury prevention. Findings underscore the potential importance of autonomy support from PE teachers in facilitating students’ sport injury prevention behaviors. Further longitudinal and intervention research is warranted to establish temporal and causal effects of TCM variables in sport injury prevention.