Objective To evaluate the preventive efficacy of an extended version of the Knee Control injury prevention exercise programme (IPEP) compared with an adductor strength programme and to a comparison group using a self-selected IPEP in amateur adolescent and adult male and female football players. Methods Two-armed cluster-randomised trial with an additional non-randomised arm. All 251 amateur teams (players 14-46 years) in one regional football district were approached. Teams meeting inclusion criteria were randomised to (1) extended Knee Control or (2) an adductor strength programme. Teams already using an IPEP were allocated to a comparison group and received no new intervention. Players responded to weekly questionnaires about football exposures and injuries during a 7-month season. Results Seventeen teams in the extended Knee Control, 12 in the adductor and 17 in the comparison group participated, with 502 players. For the primary outcomes, no difference in injury incidence in three lower-limb injury locations combined (hamstring, knee and ankle) was seen between extended Knee Control and the adductor group, whereas extended Knee Control had 29% lower incidence than the comparison group (incidence rate ratio 0.71, 95% CI 0.52 to 0.98). No between-group differences in groin injury incidence were seen. The weekly injury prevalence rates in the three lower limb locations combined (hamstring, knee and ankle) were 17% lower (prevalence rate ratio (PRR) 0.83, 95% CI 0.69 to 1.00) and 26% lower (PRR 0.74, 95% CI 0.63 to 0.87) in extended Knee Control compared with the adductor and comparison groups, respectively. Conclusion No difference in injury incidence was seen between the extended Knee Control and the adductor programme whereas extended Knee Control reduced injury incidence by nearly one-third compared with a self-selected IPEP. Players in extended Knee Control had lower injury prevalence compared with an adductor or self-selected IPEP.

PurposeTo describe the injury prevalence, injury pattern, and potential baseline risk factors for injuries in male and female adolescent and adult amateur football players.MethodsThis prospective study followed adolescent and adult amateur football players over one season March-October 2020. The study was completed by 462 players (130 men, age 20.0 & PLUSMN; 5.7, 14-46 years) who answered a baseline survey and a weekly web survey during the season. A total of 1456 weekly surveys were registered from males and 5041 from females. Injuries were recorded with the Oslo Sports Trauma Research Center Overuse Injury Questionnaire (OSTRC-O2). Potential baseline risk factors (age, performance of strength/conditioning training, participation in other sports, perceived importance of sporting success, self-rated training and match load, perceived balance between training/match load and recovery, previous/present injury at start of season, and injury beliefs) and their association with injury were analysed with Poisson regressions within each sex.ResultsMales reported 95 injuries (262 injury weeks, weekly prevalence 18.0% (95% CI 16.1-20.1)) and females 350 injuries (1206 injury weeks, weekly prevalence 23.9% (95% CI 22.8-25.1)). Gradual-onset injuries accounted for 57% of the injuries in males and 66% in females. For males, substantial injuries were most common in the hip/groin (weekly prevalence 3.8%), ankle (2.1%), posterior thigh (2.0%), and knee (2.0%); and for females, in the knee (4.3%), ankle (2.5%), and lower leg/Achilles tendon (2.0%). Significant risk factors for injury were higher age (rate ratio males 1.05 per year increase (95% CI 1.02-1.08), females 1.03 (95% CI 1.01-1.05)), and present injury at baseline (males 1.92 (95% CI 1.27-2.89), females 1.58 (95% CI 1.19-2.09)).ConclusionAt any given week, almost one in five male and one in four female amateur football players reported new or ongoing injuries. Hip/groin injuries were more frequent in males, while female players had a higher prevalence of knee injuries. Older players and those with an existing injury at the start of the season were more prone to new injury during the season. Rehabilitation of pre-season injury and complaints are key to reduce the injury burden in amateur football.

BackgroundThe Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework can be used for evaluation of implementation initiatives in sports injury prevention. The aim was to evaluate the implementation of the injury prevention exercise programme Knee Control+ among amateur clubs and coaches in one regional football district using all five dimensions of the RE-AIM framework. MethodsDissemination of Knee Control+ during the 2021 season with information and webinars within one regional football district. This was followed by a cross-sectional study with questionnaires to club personnel and coaches after the season. ResultsThe reach of Knee Control+ was fair to high, 83% of club personnel and 66% of coaches knew about the programme. 41% of club personnel and 51% of coaches had adopted it. Perceived programme effectiveness was high (6 on a 1-7 Likert scale) among coaches. Regarding implementation and maintenance, 27% of club personnel had informed coaches about Knee Control+ and 57% planned to inform coaches. The coaches had implemented the programme mainly as recommended, but half used the programme once per week or less. Intention to maintain use of the programme was high (7 on a 1-7 Likert scale) among coaches. ConclusionThe reach of Knee Control+ was fair to high, and adoption was fair in clubs, but there was a lack of policies for preventive training. Active strategies probably need to accompany dissemination of programme material. Reach, perceived effectiveness, adoption, implementation and planned maintenance were positive among coaches, but further studies are needed to analyse long-term maintenance.

BackgroundYouth participation in team ball sports is associated with a risk of both acute and gradual onset injuries but today there are several efficacious injury prevention exercise programmes (IPEPs). However, there is limited research about how to implement those programmes and the perceived barriers and facilitators among end-users.ObjectiveTo investigate perceptions of the IPEP Knee Control and facilitators and barriers to programme use among coaches and youth floorball players, and explore factors associated with planned maintenance of Knee Control.MethodsThis cross-sectional study is a sub-analysis of data from the intervention group of a cluster randomised controlled trial. Perceptions about Knee Control and facilitators and barriers to programme use were evaluated with surveys pre-intervention and post-season. 246 youth floorball players aged 12-17 years, and 35 coaches that reported no use of IPEPs during the preceding year were included. Descriptive statistics and univariate and multivariate ordinal logistic regression models were undertaken with the dependent variables: coaches planned maintenance and players opinions of maintenance of Knee Control. Independent variables were perceptions, facilitators and barriers regarding use of Knee Control and other potential influencing factors.Results88% of the players believed that Knee Control can reduce injury risk. Common facilitators to Knee Control use among coaches were support, education and high player motivation, and common barriers were that injury prevention training was time-consuming, lack of space to execute the exercises and lack of player motivation. Players who planned to maintain use of Knee Control had higher outcome expectancies and belief in ones ability to use Knee Control (action self-efficacy). Coaches who planned to maintain Knee Control had higher action self-efficacy and to a lesser extent considered that Knee Control takes too much time.ConclusionsSupport, education, and high player motivation are key facilitators, while lack of time and space for injury prevention training and boring exercises are key barriers for coaches and players to use Knee Control. High action self-efficacy among coaches and players seems to be a prerequisite for maintained use of IPEPs.

Objectives: To investigate risk factors for injury and illness in female and male youth floorball players (12-17 years) during a 26-week floorball season. Design: Prospective cohort study. Setting: Recreational youth sport. Participants: 471 players (142 females) 12-17 years. Main outcome measures: Weekly survey including questions about stress, sleep quality, well-being, sport exposure and average weekly rating of perceived exertion (RPE). Acute:chronic workload ratio (ACWR) was calculated. The Oslo Sports Trauma Research Center questionnaire on health problems was used. Predictors of new injury and illness were examined using multi-level logistic regression models with weekly measures nested within individuals. Results: Higher stress, poorer sleep quality and well-being increased the odds of a new injury in the subsequent week by 8% (2.0-13.5%), 10% (4.2-15.9%) and 8% (2.4-13.5%) per 1 unit increase. Higher stress, and poorer well-being increased the odds of illness by 8% (2.6-12.6%), and 12% (7.2-16.6%). ACWR below 0.8 or above 1.3 increased the odds of illness by 34% (4.9-70.8%). Conclusions: Perceived stress, well-being, and sleep quality were associated with injury and illness occurrence in the subsequent week. ACWR outside the range 0.8-1.3 was associated with illness the subsequent week. Trial registration: Clinical Trials registration NCT03309904. (c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

PurposeTo describe injury incidence, time trends in injury incidence, and injury characteristics among Swedish Olympic athletes over 22 years based on insurance data, as a first step to inform injury preventive measures among Olympic athletes.MethodsThe cohort comprised 762 elite athletes (54% males; age 26.5 & PLUSMN; 5.9 years) in 38 sports in the Swedish Olympic Committee support program Top and Talent between 1999 and 2020, with total 3427 athlete-years included. Acute and gradual onset injuries were reported to the insurance registry by the athletes medical staff.ResultsA total of 1635 injuries in 468 athletes were registered. The overall injury incidence was 47.7 injuries/100 athlete-years (one injury per athlete every second year). An increasing trend in injury incidence was observed in the first decade 2001 to 2010 (annual change 6.0%, 95% CI 3.3-8.8%), while in the second decade 2011 to 2020 no change was evident (0.4%, 95% CI - 1.9 to 2.7%). Gymnastics, tennis, and athletics had the highest incidence (100.0, 99.3, and 93.4 injuries/100 athlete-years, respectively). Among sport categories, mixed and power sports had the highest incidence (72.8 and 69.5 injuries/100 athlete-years, respectively). Higher incidences were seen in the younger age groups (& LE; 25 years) in mixed and skill sports. The injury incidence was comparable between male and female athletes, and summer and winter sports. Most injuries occurred in the lower limb, and specifically the knee (24%), foot/ankle (15%) and spine/pelvis (13%).ConclusionThe results on injury patterns in different sports and age groups may guide preventive focus for health and performance teams working with Olympic athletes.

Purpose To translate the ACL-QOL from English to Swedish and evaluate measurement properties for use after surgical and non-surgical management of anterior cruciate ligament (ACL) injury. Methods The ACL-QOL was translated from English to Swedish and data were pooled from 13 cohorts to enable a comprehensive evaluation of measurement properties in line with COSMIN guidelines. We evaluated internal consistency, test-re-test reliability, measurement error, structural validity [confirmatory factor analysis (CFA)], construct validity and responsiveness (hypothesis testing), and floor/ceiling effects. Results were stratified by time since injury (<= 1.5 years; 2-10 years, 15-25 years; > 30 years) and ACL management strategy [surgical (n = 1163), non-surgical (n = 570)]. Results The Swedish ACL-QOL had sufficient internal consistency (total and domain scores) for use in surgically managed (Cronbachs alpha >= 0.744) and non-surgically managed (>= 0.770) ACL-injured individuals at all time-points. Test-re-test reliability was sufficient [intraclass correlation coefficients: all domains > 0.80, total score 0.93 (95% CI 0.86-0.96)]. The standard error of measurement was 5.6 for the total score and ranged from 7.0 to 10.3 for each domain. CFA indicated sufficient SRMR values when using the total score or five domains; however, CFI and RMSEA values did not meet cut-offs for good model fit. Hypothesis testing indicated sufficient construct validity and responsiveness. Floor effects were negligible and ceiling effects were negligible or minor. Conclusion The Swedish version of the ACL-QOL has sufficient internal consistency, test-re-test reliability, construct validity and responsiveness, for use in people with ACL injury managed with or without ACL surgery. Model fit could be improved and investigation into the source of misfit is warranted.

OBJECTIVES: Analyse changes in knee laxity between 3, 6, 12 and 24 months after non-surgically treated ACL injury and to analyse associations between knee laxity and knee function, self-reported knee stability, ACL-Return to Sport after Injury (ACL-RSI), fear and confidence at different timepoints during recovery.

DESIGN: Prospective cohort study.

PARTICIPANTS: 125 patients (67 males, mean age 25.0 ± 7.0 years) with acute ACL injury.

MAIN OUTCOME: Laxity was measured using KT-1000 arthrometer. Self-reported knee function was assessed using the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF). Confidence and fear were assessed with questions from the ACL-RSI scale. Subjectively knee stability was assessed using SANE.

RESULTS: Knee laxity increased bilaterally from 3 to 12 months, and in the non-involved knee from 3 to 24 months (p˂0.05), although mean change was below 1 mm. Side-to-side difference in knee laxity was correlated with IKDC-SKF (r = -0.283) and knee stability in rehabilitation/sport activities (r = -0.315) at 6 months, but not with confidence/fear.

CONCLUSION: Knee laxity increased bilaterally during the first year after non-surgically treated ACL injury, though, the mean change in knee laxity was below 1 mm and the clinical significance is unknown. Knee laxity was weakly associated with knee function and perceived knee stability.

LEVEL OF EVIDENCE: Level II TRIAL REGISTRATION: NCT02931084.

Purpose Evaluate team and player compliance with the Knee Control injury prevention exercise programme, study the association between player compliance and injury rates, and compare coach demographics, baseline prevention expectancies, and programme utilisation between teams with high and low compliance. Methods Prospective one-season cohort study based on a cluster randomised controlled trial on 301 (107 female) floorball players aged 12-17 years. Floorball exposure and injuries were self-reported weekly by players using the Oslo Sports Trauma Research Center questionnaire. Team and player compliance to Knee Control was reported monthly by coaches. Additionally, coaches answered pre- and post-season surveys. Teams were divided into a high (>= 80%) or low (< 80%) compliance group based on their use of Knee Control during the season. Players were divided into three compliance groups based on their average weekly number of Knee Control sessions; high (>= 2 sessions), intermediate (>= 1 to < 2 sessions), and low dose (< 1 session). Results Mean team compliance for the high and low compliance groups were 95% (range 82-100) and 50% (range 13-66), respectively. Mean +/- SD weekly Knee Control dose in the three player compliance groups were 2.4 +/- 0.3, 1.4 +/- 0.3, and 0.7 +/- 0.3 sessions, respectively. There were no differences in total injury incidence between the player compliance groups, but players in the high-dose group had a 35% lower prevalence of injuries overall [adjusted prevalence rate ratio (PRR) 0.65, 95% CI 0.48-0.89] and 60% lower prevalence of substantial injuries (adjusted PRR 0.40, 95% CI 0.26-0.61) compared with the low-dose group. Male players in the high-dose group had consistently lower injury incidence and prevalence, while no between compliance group differences were seen in female players. There were no differences in sex, years of coaching experience, or baseline prevention expectancies in general between coaches for teams in the high vs. low compliance groups, but teams in the high compliance group had a better utilisation fidelity. Conclusion There was a clear dose-response relationship between more frequent Knee Control use and lower injury rates in male floorball players, but not in female players. Teams with higher compliance also showed a better utilisation fidelity with the programme.

Objectives: To compare neuromuscular control and hop performance between youth and adult male and female football players. Design: Cross-sectional study. Participants: 119 youth players (13-16 years; 68 males) and 88 adult players (17-26 years; 44 males). Main outcome measures: Neuromuscular control assessed with drop vertical jump (DVJ) and tuck jump assessment (TJA). Hop performance assessed with single-leg hop for distance and side hop. Results: Adult females had smaller normalized knee separation distances (NKSD) during DVJ at initial contact (77.9 +/- 18.5 vs. 86.1 +/- 11.0, p = 0.010) and at maximum knee flexion (59.7 +/- 23.4 vs.74.1 +/- 18.1, p = 0.001) compared to youth females. TJA revealed more technique errors in youths compared to adults (males 10 (8-11) vs. 8 (7-10); females 11 (9-12) vs. 9 (8-11), p < 0.05). Youths demonstrated inferior hop performance (males single-leg hop 142 +/- 18 vs. 163 +/- 17, side hop 41 +/- 12 vs. 52 +/- 12, p < 0.001; females side hop 32 +/- 10 vs. 38 +/- 14, p < 0.05). Conclusions: Youth players demonstrated reduced neuromuscular control during TJA and inferior hop performance compared to adult players. Adult female players demonstrated greater knee valgus during DVJ compared to youth female players.

Objectives: To describe and compare patients appraisal of the rehabilitation and adherence to the rehabilitation program after acute ACL injury treated with (ACLR) or without (non-ACLR) reconstruction.

Design: Prospective cohort study.

Participants: 275 patients (143 females; mean age 25 +/- 7 years) with acute ACL injury, of whom 166 patients had ACLR within 24 months.

Main outcome: Adherence to rehabilitation was assessed using the modified Sports Injury Rehabilitation Adherence Scale (SIRAS).

Results: Appraisal of rehabilitation was higher in the post-ACLR group compared to the non-ACLR group at 3 months (91% compared to 70% scored rehabilitation as necessary, p = 0.025) and at 6 months (87% compared to 70% scored it as necessary, p = 0.017). SIRAS score did not differ between 3 and 6 months for the non-ACLR group (median (IQR) 13 (2) vs 13 (2)) or the post-ACLR group (14 (1) vs 14 (2), p>0.05). The post-ACLR group had a higher SIRAS score than the non-ACLR group at 3 and 6 months (p ≤0.001).

Conclusion: Patients treated with ACLR reported valuing their rehabilitation more and rated greater adherence to the rehabilitation programme than non-surgically treated patients. As rehabilitation is essential for good knee function, strategies to improve adherence after non-ACLR treatment should be implemented.

Background: In the treatment of anterior cruciate ligament (ACL) injuries, there is little evidence of when and why a decision for ACL reconstruction (ACLR) or nonoperative treatment (non-ACLR) is made. Purpose: To (1) describe the key characteristics of ACL injury treatment decisions and (2) compare patient-reported knee instability, function, and preinjury activity level between patients with non-ACLR and ACLR treatment decisions. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 216 patients with acute ACL injury were evaluated during the first year after injury. The treatment decision was non-ACLR in 73 patients and ACLR in 143. Reasons guiding treatment decision were obtained from medical charts and questionnaires to patients and orthopaedic surgeons. Patient-reported instability and function were obtained via questionnaires and compared between patients with non-ACLR and ACLR treatment decisions. The ACLR treatment group was classified retrospectively by decision phase: acute phase (decision made between injury day and 31 days after injury), subacute phase (decision made between 32 days and up to 5 months after injury), and late phase (decision made 5-12 months after injury). Data were evaluated using descriptive statistics, and group comparisons were made using parametric or nonparametric tests as appropriate. Results: The main reasons for a non-ACLR treatment decision were no knee instability and no problems with knee function. The main reasons for an ACLR treatment decision were high activity demands and knee instability. Patients in the non-ACLR group were significantly older (P = .031) and had a lower preinjury activity level than did those in the acute-phase (P < .01) and subacute-phase (P = .006) ACLR decision groups. There were no differences in patient-reported instability and function between treatment decision groups at baseline, 4 weeks after injury, or 3 months after injury. Conclusion: Activity demands, not patient-reported knee instability, may be the most important factor in the decision-making process for treatment after ACL injury. We suggest a decision-making algorithm for patients with ACL injuries and no high activity demands; waiting for >3 months can help distinguish those who need surgical intervention from those who can undergo nonoperative management.

Objectives: The primary aim was to assess impact of early knee status on self-reported knee function at 3 and 12 months and on quadriceps strength at 12 months after non-surgically treated ACL injury. The secondary aim was to describe the recovery of muscle strength during the first year after the injury. Design: Prospective cohort study. Participants: 70 patients (42 males; mean age 27 +/- 7 years) with acute ACL injury. Main outcome: Knee symptoms, knee function and sporting activities were assessed with the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF). Muscle strength was assessed with an isokinetic dynamometer. Clinical assessment performed at baseline was used to evaluate early knee status. Results: Global knee function, knee joint stability during ADL, gait pattern and one-legged squat assessed in mean 2 weeks after injury hadimpact on self-reported knee function at 3 and 12 months (r(2) 0.105-0.267). Mean limb symmetry index (LSI) of muscle strength and jump performance were 91-98% at 12 months. Conclusion: Early knee symptoms affect self-reported knee function at 3 and 12 months, while other factors are important for gaining muscle strength. Muscle strength recovered during the first year after ACL injury and reached mean LSI above 90%. (C) 2021 The Authors. Published by Elsevier Ltd.

Objective To describe weekly illness prevalence and illness symptoms by sex in youth floorball players during one season. Design Prospective cohort study. Setting Players who were registered to play community level floorball during the 2017-2018 season (26 weeks) in two provinces in southern Sweden. Participants 471 youth players aged 12-17 years. Mean (SD) age for 329 male players 13.3 (1.0) years and 142 female players 13.7 (1.5) years. Primary and secondary outcome measures Weekly self-reported illness prevalence and illness symptoms according to the 2020 International Olympic Committees consensus recommendations. Results 61% of youth floorball players reported at least one illness week during the season, with an average weekly illness prevalence of 12% (95% Cl 10.8% to 12.3%). The prevalence was slightly higher among females (13%, 95% CI 11.6% to 14.3%) than males (11%, 95% Cl 9.9% to 11.7%), prevalence rate ratio 1.20 (95% CI 1.05 to 1.37, p=0.009). In total, 49% (53% male, 43% female) of illness reports indicated that the player could not participate in floorball (time loss), with a mean (SD) absence of 2.0 (1.7) days per illness week. Fever (30%), sore throat (16%) and cough (14%) were the most common symptoms. Female players more often reported difficulty in breathing/tight airways and fainting, and male players more often reported coughing, feeling tired/ feverish and headache. Illness prevalence was highest in the peak winter months (late January/February) reaching 15%-18% during this period. Conclusions Our novel findings of the illness prevalence and symptoms in youth floorball may help direct prevention strategies. Athletes, coaches, parents and support personnel need to be educated about risk mitigation strategies.

Objectives: To investigate intra- and interrater reliability of the subjective assessments of filmed DVJ and TJA in youth male and female soccer players and to compare subjective assessment of the DVJ with two-dimensional movement analysis. Design: Cross-sectional study. Participants: 115 soccer players (66 boys, 49 girls) mean age 14 +/- 1 (range 13-16) years. Main outcome measures: Knee control during landing phase of DVJ was assessed using a 3-graded scoring scale. TJA was assessed according to ten criteria using a dichotomous grading scale. Subjective assessment of DVJ was compared with calculation of normalized knee separation distance (NKSD). Results: Intrarater reliability for DVJ was substantial to almost perfect (kappa 0.72 rater 1; 0.85 rater 2). Interrater reliability was substantial to almost perfect (kappa from 0.68 to 0.83). The TJA total score intrarater reliability was ICC 0.59 for rater 1 and 0.90 for rater 2. Interrater reliability ranged from ICC 0.51 to 0.60. There were between-group differences in mean NKSD during DVJ for players rated as 0, 1 and 2, but within-group variability was large. Conclusion: Assessment of DVJ and TJA in youth athletes was rater dependent. Players with subjectively assessed reduced or poor knee control had smaller normalized knee separation distance in DVJ. (C) 2020 The Authors. Published by Elsevier Ltd.

Objective: Describe a consecutive cohort of people with a non-surgically treated ACL injury and evaluate correlations between functional performance and patient reported outcome measures (PROMs). Design: Cross-sectional. Participants: Sixty-eight individuals (38 males, 18-45 years old) 2-5 years after ACL injury. Main outcome measures: Tegner Activity Scale, International Knee Documentation Committee Subjective Knee Form (IKDC-SKF), Anterior Cruciate Ligament Return to Sport after Injury scale (ACL-RSI) and ACL-Quality of Life (ACL-QoL) were completed. Functional performance was assessed using 4 hop tests and a squat test. Results: Mean IKDC-SKF score was 72 +/- 17 and mean LSI on performance tests were above 90%. Tegner Activity Scale was reduced from median 8 pre-injury to 5 at follow up. Satisfaction with activity level was median 7 on a 10-point ordinal scale. Correlations were moderate to strong (r = 0.552-0.856) between PROMs, negligible to weak (r = 0.003-0.403) between performance tests and PROMs and negligible to moderate (r = 0.142-0.683) between performance tests. Conclusion: Functional performance had negligible or weak correlation to PROMs, which indicates the need for multi-modal assessment strategies. Activity level was reduced 2-5 years after a non-surgically treated ACL injury, but most patients were able to resume physical activity at a sufficient level to maintain health and displayed symmetrical functional performance. (C) 2020 The Authors. Published by Elsevier Ltd.

Purpose This study aimed at evaluating the correlation between seven different performance tests and two neuromuscular control tests in youth football players and to evaluate the influence of sex and age groups on test results. Methods One-hundred and fifteen football players (66 boys, 49 girls) mean age 14 +/- 0.7 (range 13-16) years from youth teams were tested at the start of the second half of the competitive season. A test battery including agility t-test, 505 agility test, single-leg hop for distance test, side-hop test, countermovement jump test, 10-m sprint test, 20-m sprint test, tuck jump assessment (TJA) and drop vertical jump (DVJ) was completed. Results Correlations between the seven different performance tests of agility, jump and sprint ability were generally moderate to strong (r = 0.534-0.971). DVJ did not correlate with the performance tests (rho = 0.004 to - 0.101) or with TJA total score (rho = 0.127). There were weak to moderate correlations between TJA total score and the performance tests (r = - 0.323-0.523). Boys performed better than girls in all performance tests (p 0.001) and in TJA total score (p = 0.002). In boys, older players performed better than younger players in the majority of the tests, while there was no clear age influence among girls. Conclusion Sprint performance was moderately to strongly correlated with agility and jump performance, and performance tests were weakly to moderately correlated to TJA, while DVJ did not correlate with the other tests. Boys performed better than girls on performance tests and TJA. An age effect on performance was evident in boys but not in girls.

Objective To study whether an injury prevention exercise programme would reduce the number of injuries in youth floorball players. Methods 81 youth community level floorball teams (48 clusters=clubs) with female and male players (12-17 years) were cluster-randomised into an intervention or control group. Intervention group coaches were instructed to use the Swedish Knee Control programme and a standard running warm-up before every training session, and the running warm-up before every match, during the season. Control teams continued usual training. Teams were followed during the 2017/2018 competitive season (26 weeks). Player exposure to floorball and occurrence of acute and overuse injuries were reported weekly via a web-based player survey using the Oslo Sports Trauma Research Centre Questionnaire. Results 17 clusters (301 players) in the intervention group and 12 clusters (170 players) in the control group were included for analyses. There were 349 unique injuries in 222 players. The intervention group had a 35% lower incidence of injuries overall than the control group (adjusted incidence rate ratio (IRR) 0.65, 95% CI 0.52 to 0.81). The absolute risk reduction was 6.6% (95% CI 3.2 to 10.0), and the number needed to treat was 152 hours of floorball exposure (95% CI 100 to 316). Intervention group teams had a 45% lower incidence of acute injuries (adjusted IRR 0.55, 95% CI 0.37 to 0.83). There was no difference in the prevalence of overuse injuries (adjusted prevalence rate ratio 0.96, 95% CI 0.73 to 1.26). Conclusion The Knee Control injury prevention programme reduced acute injuries in youth floorball players; there was no effect on overuse injuries.

Background:

Arthroscopic meniscal surgery is a common orthopaedic procedure in middle-aged patients, but the efficacy of this procedure has been questioned. In this study, we followed up the only randomized controlled trial that has shown a 1-year benefit from knee arthroscopic surgery with an exercise program compared with an exercise program alone.

Purpose:

To (1) evaluate whether knee arthroscopic surgery combined with an exercise program provided an additional 5-year benefit compared with an exercise program alone in middle-aged patients with meniscal symptoms, (2) determine whether baseline mechanical symptoms affected the outcome, and (3) compare radiographic changes between treatment groups.

Study Design:

Randomized controlled trial; Level of evidence, 1.

Methods:

Of 179 eligible patients aged 45 to 64 years, 150 were randomized to either a 3-month exercise program (nonsurgery group) or to the same exercise program plus knee arthroscopic surgery (surgery group) within 4 weeks. Radiographs were assessed, according to the Kellgren-Lawrence grade, at baseline and at the 5-year follow-up. The primary outcome was the change in Knee injury and Osteoarthritis Outcome Score (KOOS)–Pain (KOOS_PAIN) subscore from baseline to the 5-year follow-up. We performed an as-treated analysis.

Results:

A total of 102 patients completed the 5-year questionnaire. At the 5-year follow-up, both groups had significant improvement in KOOS_PAIN subscores, although there was no significant change from the 3-year scores. There was no between-group difference in the change in the KOOS_PAIN subscore from baseline to 5 years (3.2 points [95% CI, –6.1 to 12.4]; adjusted P = .403). In the surgery group, improvement was greater in patients without mechanical symptoms than in those with mechanical symptoms (mean difference, 18.4 points [95% CI, 8.7 to 28.1]; P < .001). Radiographic deterioration occurred in 60% of patients in the surgery group and 37% of those in the nonsurgery group (P = .060).

Conclusion:

Knee arthroscopic surgery combined with an exercise program provided no additional long-term benefit after 5 years compared with the exercise program alone in middle-aged patients with meniscal symptoms. Surgical outcomes were better in patients without mechanical symptoms than in patients with mechanical symptoms during the preoperative period. Radiographic changes did not differ between treatment groups.

Registration:

NCT01288768 (ClinicalTrials.gov identifier).

Background: When deciding medical treatment, patients perspectives are important. There is limited knowledge about patients views when choosing non-operative treatment or anterior cruciate ligament (ACL) reconstruction (ACLR) after ACL injury. Purpose: To describe reasons that influenced patients decisions for non-operative treatment or ACLR after ACL injury. Study Design: Cross-sectional study. Methods: This study recruited a total of 223 patients (50% men), aged 28 +/- 8 years who had sustained ACL injury, either unilateral or bilateral. Subjects were, at different time points after injury, asked to fill out a questionnaire about their choice of treatment, where an ACLR treatment decision was made, some responded before and some after the ACLR treatment. A rating of the strength of 10 predetermined reasons in their choice of treatment graded as 0 (no reason) to 3 (very strong reason), was done. Results: Patients with unilateral ACL injury treated with ACLR (110 patients) rated "inability to perform physical activity at the same level as before the injury due to impaired knee function" (96%), "fear of increased symptoms during activity" (87%) and "giving way episodes" (83%) as strong or very strong reasons in their treatment decision. Patients with bilateral ACL injury treated with ACLR (109 knees) rated similar reasons as patients with unilateral ACLR and also "low confidence in the ability to perform at the preinjury activity level without ACLR" (80%) as strong or very strong reasons. Patients with unilateral ACL injury treated non-operatively (96 patients) rated "advice from clinician" (69%) as a strong or very strong reason. Patients with bilateral ACL injury treated non-operatively (25 knees) rated "absence of giving way episodes" (62%), and "no feeling of instability" (62%) as strong or very strong reasons. Conclusion: Inability to perform physical activity, fear of increased symptoms, and giving way episodes were reasons that patients with ACL injury considered when making decisions about ACLR. When choosing non-operative treatment, patients considered the absence of instability or giving way symptoms, being able to perform physical activity, and advice from clinicians.

The purpose of the study was to (1) study and compare the factors that Swedish orthopaedic surgeons and physical therapists consider important for recommending ACL reconstruction and, (2) to assess how orthopaedic surgeons and physical therapists consider their own and each others, as well as patients, roles are in the treatment decision. A web-based survey assessing the relevance of 21 predetermined factors, in the choice to recommend ACL reconstruction, was sent to orthopaedic surgeons and physical therapists. Respondents were also asked to rate the importance of the assessment made by themselves, the other clinician (physical therapists rated the importance of surgeons, surgeons rated the importance of physical therapists), and the patients preferences. Orthopaedic surgeons agreed of eight, and physical therapists of seven factors as important in the choice to recommend ACL reconstruction. The factors both groups reported as important were; "patients wishes to return to contact/pivoting sports", "instability in physical activity", "instability in activities of daily living despite adequate rehabilitation", "physically demanding occupation", and "young age". Both professions rated their own and each others assessments as well as patients wishes as important for the decision to recommend ACL reconstruction. Orthopaedic surgeons and physical therapists agree about factors that are important for their decision to recommend ACL reconstruction, showing that both professions share a common ground in perceptions of factors that are important in recommending ACL reconstruction. Diagnostic study: Level III.

The aim of our study was to cross-sectionally compare patient-reported knee function outcomes between people who chose non-surgical treatment for ACL injury and those who chose ACL reconstruction. We extracted Knee Injury and Osteoarthritis Outcome Score (KOOS) and EuroQoL-5D data entered into the Swedish National ACL Registry by patients with a non-surgically treated ACL injury within 180 days of injury (n = 306), 1 (n = 350), 2 (n = 358), and 5 years (n = 114) after injury. These data were compared cross-sectionally to data collected pre-operatively (n = 306) and at 1 (n = 350), 2 (n = 358), and 5 years (n = 114) post-operatively from age- and gender-matched groups of patients with primary ACL reconstruction. At the 1 and 2 year comparisons, patients who chose surgical treatment reported superior quality of life and function in sports (1 year mean difference 12.4 and 13.2 points, respectively; 2 year mean difference 4.5 and 6.9 points, respectively) compared to those who chose non-surgical treatment. Patients who chose ACL reconstruction reported superior outcomes for knee symptoms and function, and in knee-specific and health-related quality of life, compared to patients who chose non-surgical treatment.

PURPOSE:

To compare dynamic and static tibial translation, in patients with anterior cruciate ligament deficiency, at 2- to 5-year follow-up, with the tibial translation after 4 months of rehabilitation initiated early after the injury. Secondarily, to compare tibial translation in the injured knee and non-injured knee and explore correlations between dynamic and static tibial translation.

METHODS:

Twelve patients with ACL rupture were assessed at 3-8 weeks after ACL injury, after 4 months of structured rehabilitation, and 2-5 years after ACL injury. Sagittal tibial translation was measured during the Lachman test (static translation) and during gait (dynamic translation) using a CA-4000 electrogoniometer.

RESULTS:

Static tibial translation was increased bilateral 2-5 years after ACL injury, whereas the dynamic tibial translation was unchanged. Tibial translation was greater in the injured knee compared with the non-injured knee (Lachman test 134 N 9.1 ± 1.0 vs. 7.0 ± 1.7 mm, P = 0.001, gait 5.6 ± 2.1 vs. 4.7 ± 1.8 mm, P = 0.011). There were no correlations between dynamic and static tibial translation.

CONCLUSION:

Dynamic tibial translation was unchanged in spite of increased static tibial translation in the ACL-deficient knee at 2- to 5-year follow-up compared to directly after rehabilitation. Dynamic tibial translation did not correlate with the static tibial translation. A more normal gait kinematics may be maintained from completion of a rehabilitation programme to mid-term follow-up in patients with ACL deficiency treated with rehabilitation only.

Background: The optimal treatment for middle-aged patients with knee pain and meniscal lesions has been extensively debated. Most previous studies have revealed only short-term beneficial results of knee arthroscopic surgery. The authors have previously shown a positive benefit of knee arthroscopic surgery and an exercise program after 1 year when compared with an exercise program alone. Purpose: To evaluate if knee arthroscopic surgery combined with an exercise program provided an additional long-term benefit after 3 years compared with an exercise program alone in middle-aged patients with meniscal symptoms. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Of 179 eligible patients, aged 45 to 64 years, 150 were randomized to (1) a 3-month exercise program (nonsurgery group) or (2) the same as group 1 plus knee arthroscopic surgery within 4 weeks (surgery group). The primary outcome was the change in the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscore of pain between baseline and the 3-year follow-up. Results from the 1-year follow-up have been published previously. Results: Both treatment groups improved significantly in the KOOS pain subscore at 3 years follow-up in the intention-to-treat and as-treated analyses (P amp;lt; .001). The between-group difference for the change in the KOOS pain subscore between baseline and the 3-year follow-up was no longer statistically significant, neither in the intention-to-treat analysis (7.6 points; 95% CI, -0.6 to 15.9; P = .068) nor in the as-treated analysis (5.3 points; 95% CI, -3.1 to 13.8; P = .216). The factorial analysis of the effect of the intervention and age, onset of pain, and mechanical symptoms indicated that older patients improved more, regardless of treatment, and surgery may be more beneficial for patients without mechanical symptoms (as-treated analysis). The effect of the predictive factors on the KOOS pain subscore was uncertain because of the small sample size in the subgroup analyses. Conclusion: The benefit of knee arthroscopic surgery, seen at 1 year in middle-aged patients with meniscal symptoms, was diminished at 3 years and was no longer statistically significant.

PURPOSE: To describe individuals' expectations, motivation, and satisfaction before, during, and after rehabilitation for ACL reconstruction and to explore how these factors were associated with return to pre-injury sport activity at 1-year follow-up.

METHODS: Sixty-five individuals (34 males), median age 22 (15-45) years, scheduled for ACL reconstruction participated. Participants completed the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) and questions about expectations, satisfaction, and motivation pre-operatively and at 16 and 52 weeks after surgery.

RESULTS: Prior to surgery, 86 % of participants stated that their goal was to return to their pre-injury sport activity. Those who had returned to their pre-injury sport activity at 52 weeks were more motivated during rehabilitation to return to their pre-injury activity level, more satisfied with their activity level and knee function at 52 weeks, and scored significantly higher on the IKDC-SKF [median 92.0 (range 66.7-100.0)] at 52 weeks, compared to those who had not returned [median 77.6 (range 50.6-97.7)].

CONCLUSION: Prior to ACL reconstruction, most participants expected to return to their pre-injury activity level. Higher motivation during rehabilitation was associated with returning to the pre-injury sport activity. The participants who had returned to their pre-injury sport activity were more satisfied with their activity level and knee function 1 year after the ACL reconstruction. Facilitating motivation might be important to support individuals in achieving their participation goals after ACL reconstruction.

LEVEL OF EVIDENCE: Prospective cohort study, Level II.

To translate to Swedish language and cross-culturally adapt the IKDC-SKF and to test the measurement properties of the Swedish version of IKDC-SKF in ACL-injured patients undergoing reconstruction surgery.The translation and cross-cultural adaption was performed according to guidelines. Seventy-six patients with an ACL injury filled out the IKDC-SKF and other questionnaires before ACL reconstruction and at 4, 6, and 12months after surgery. A total of 203 patients from the Swedish ACL Registry participated at 8months post-operative. Measurement properties were tested according to the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidelines.The Swedish IKDC-SKF had high internal consistency (Cronbachs alpha=0.90) and test-retest reliability (ICC2,1=0.92, CI 95%: 0.81-0.97, Pamp;lt;.001). A single factor solution accounted for 46.1% of the variance in IKDC-SKF scores. Criterion validity was moderate to high. All ten predefined hypotheses for hypothesis testing were confirmed. The six hypotheses for responsiveness testing were confirmed. The effect size was 1.8, the standardized response mean was 1.9, the and minimal clinically important difference was 13.9 points.The Swedish version of the IKDC-SKF had good measurement properties and can be recommended for use in a population of ACL-deficient patients undergoing ACL reconstruction.

The aim was to compare fear of re-injury, patient reported function, static and dynamic tibial translation and muscle strength assessed before and 5 weeks after an anterior cruciate ligament (ACL) reconstruction between individuals who sustained a subsequent ACL graft rupture or a contralateral ACL injury within 5 years after the reconstruction, and individuals with no subsequent injury. Nineteen patients were investigated before, and 5 weeks after an ACL reconstruction with a quadruple hamstring tendon graft. At 5 years follow up, 3 patients had sustained an ACL graft rupture and 2 patients had sustained a contralateral ACL rupture. Fear of re-injury, confidence with the knee, patient reported function, activity level, static and dynamic tibial translation and muscle strength were assessed. The re-injured group reported greater fear of re-injury and had greater static tibial translation in both knees before the ACL reconstruction compared to those who did not sustain another ACL injury. There were no other differences between groups. In conclusion, fear of re-injury and static tibial translation before the index ACL reconstruction were greater in patients who later on suffered an ACL graft rupture or a contralateral ACL rupture. These factors may predict a subsequent ACL injury.

Purpose: To assess whether patient-reported outcomes (psychological factors, appraisals of knee function, and physical activity participation) were associated with satisfaction with knee function after anterior cruciate ligament (ACL) reconstruction. Methods: Participants who were aged 18 to 45 years and a minimum 12 months post primary ACL reconstruction completed a questionnaire battery evaluating knee self-efficacy, knee-related quality of life, self-reported function, and physical activity participation. Participants responses to the question "If you were to spend the rest of your life with your knee just the way it has been in the last week, would you feel.... (7-point ordinal scale; 1 = happy, 7 = unhappy)" were categorized as satisfied, mostly satisfied, or dissatisfied and used as the primary outcome. Ordinal regression was used to examine associations between independent variables and the primary outcome. Results: A total of 177 participants were included at an average of 3 years after primary ACL reconstruction. At follow-up, 44% reported they would be satisfied, 28% mostly satisfied, and 28% dissatisfied with the outcome of ACL reconstruction. There were significant differences in psychological responses and appraisal of knee function between the 3 groups (P = .001), and significantly more people in the satisfied group had returned to their preinjury activity (58%) than in the mostly satisfied (28%) and dissatisfied (26%) groups (P = .001). Multivariable analysis demonstrated that the odds of being satisfied increased by a factor of 3 with higher self-efficacy, greater knee-related quality of life, and returning to the preinjury activity. Conclusions: People who had returned to their preinjury physical activity and who reported higher knee-related self-efficacy and quality of life were more likely to be satisfied with the outcome of ACL reconstruction.

PURPOSE: To evaluate static and dynamic tibial translation before, 5 weeks after, and 5 years after anterior cruciate ligament (ACL) reconstruction. To explore whether static and dynamic tibial translation are correlated.

METHODS: Ten patients undergoing quadruple hamstring tendon graft ACL reconstruction were evaluated before, 5 weeks after, and 5 years after ACL reconstruction. Sagittal tibial translation was measured during the Lachman test (static translation) and during gait (dynamic translation) using a CA-4000 electrogoniometer.

RESULTS: Five years after ACL reconstruction, static tibial translation did not differ between knees (Lachman test 90 N and 134 N n.s.). In contrast, there was greater maximal anterior tibial translation during gait in ACL-reconstructed knees than in uninjured knees (5.5 ± 1.4 vs. 4.5 ± 1.6 mm, P = 0.028). There were no differences in static or dynamic tibial translation between the 5-year follow-up and before ACL reconstruction or between the 5-year follow-up and the 5-week follow-up. There were no correlations between static and dynamic tibial translation.

CONCLUSION: Although static tibial translation did not differ between knees 5 years after ACL reconstruction, dynamic tibial translation during gait was greater in ACL-reconstructed knees than in uninjured knees. Neither static nor dynamic tibial translation changed 5 years after ACL reconstruction as compared to before surgery and 5 weeks after surgery. Static tibial translation did not correlate with dynamic tibial translation.

CLINICAL RELEVANCE: This study indicates that although the knee is stable during static measurements, kinematics during gait is impaired 5 years after ACL reconstruction. This may affect the return to sport and risk of osteoarthritis.

LEVEL OF EVIDENCE: Case series, Level IV.

Objective: There is no evidence that a knee arthroscopy is more beneficial to middle-aged patients with meniscal symptoms compared to other treatments. This randomised controlled trial aimed to determine whether an arthroscopic intervention combined with a structured exercise programme would provide more benefit than a structured exercise programme alone for middle-aged patients with meniscal symptoms that have undergone physiotherapy. Method: 150 out of 179 eligible patients, aged 45 to 64 (mean: 54 +/- 5), symptom duration more than 3 months and standing X-ray with Ahlback grade 0, were randomised to: (1) a physiotherapy appointment within 2 weeks of inclusion that included instructions for a 3-month exercise programme (non-surgery group); or (2) the same as (1) plus, within 4 weeks of inclusion, knee arthroscopy for resection of any significant meniscal injuries (surgery group). The primary outcome was change in pain at 12 months, assessed with the Knee Injury and Osteoarthritis Outcome Score (KOOSPAIN). Results: In the Intention-To-Treat analysis, pain at 12 months was significantly lower in the surgery than in the non-surgery group. The change in KOOSPAIN was significantly larger in the surgery than in the non-surgery group (between-group difference was 10.6 points of change; 95% CI: 3.4 to 17.7, P = 0.004). The As-Treated analysis results were consistent with the Intention-To-Treat analysis results. Conclusion: Middle-aged patients with meniscal symptoms may benefit from arthroscopic surgery in addition to a structured exercise programme. Patients age or symptom history (i.e., mechanical symptoms or acute onset of symptoms) didnt affect the outcome.

Background This cross-sectional study aimed to examine whether appraisal of knee function, psychological and demographic factors were related to returning to the preinjury sport and recreational activity following anterior cruciate ligament (ACL) reconstruction. Method 164 participants completed a questionnaire battery at 1-7 years after primary ACL reconstruction. The battery included questionnaires evaluating knee self-efficacy, health locus of control, psychological readiness to return to sport and recreational activity, and fear of reinjury; and self-reported knee function in sport-specific tasks, knee-related quality of life and satisfaction with knee function. The primary outcome was returning to the preinjury sport or recreational activity. Results At follow-up, 40% (66/164) had returned to their preinjury activity. Those who returned had more positive psychological responses, reported better knee function in sport and recreational activities, perceived a higher knee-related quality of life and were more satisfied with their current knee function. The main reasons for not returning were not trusting the knee (28%), fear of a new injury (24%) and poor knee function (22%). Psychological readiness to return to sport and recreational activity, measured with the ACL-Return to Sport after Injury scale (was most strongly associated with returning to the preinjury activity). Age, sex and preinjury activity level were not related. Conclusions Less than 50% returned to their preinjury sport or recreational activity after ACL reconstruction. Psychological readiness to return to sport and recreation was the factor most strongly associated with returning to the preinjury activity. Including interventions aimed at improving this in postoperative rehabilitation programmes could be warranted to improve the rate of return to sport and recreational activities.

Background: Differences in knee joint stabilization between children and adults and between the sexes are not fully understood. Purpose: To compare the knee laxity and the dynamic tibial translation between (1) children and adults, (2) girls and boys, and (3) women and men. Study Design: Controlled laboratory study.

Methods: Sixty-seven children (aged 8-13 years) and 63 adults (aged 18-30 years) without previous knee injuries participated. Sagittal tibial translation was measured during the instrumented Lachman test at 90 N and 134 N (knee laxity) and during gait (dynamic translation). Tibial translation was recorded with an electrogoniometer.

Results: Knee laxity was greater in children than in adults (Lachman test at 90 N: 9.1 +/- 2.9 vs 7.3 +/- 2.7, respectively; P less than .001). In contrast, dynamic tibial translation during gait did not differ between children and adults. Girls and boys did not differ in knee laxity or maximum anterior tibial translation during gait, and men and women did not differ in knee laxity. Women had greater dynamic tibial translation during gait than men (7.8 +/- 2.7 vs 5.7 +/- 3.0, respectively; P = .004).

Conclusion: Children had greater knee laxity than adults, whereas the dynamic tibial translation did not differ. In adults, knee laxity did not differ between the sexes, but dynamic tibial translation was greater in women. Clinical Relevance: Children and men had less dynamic tibial translation during gait in proportion to their maximum knee laxity. The observed less dynamic tibial translation in children and adult men might be related to their reduced risk of sustaining an anterior cruciate ligament injury.

Psychological factors may be a hindrance for returning to sport after an anterior cruciate ligament (ACL) reconstruction. The ACL-Return to Sport after Injury scale (ACL-RSI) measures athletes emotions, confidence in performance, and risk appraisal in relation to return to sport. The aim of this study was to translate the ACL-RSI scale from English to Swedish and to examine some of the measurement properties of the Swedish version. The ACL-RSI was translated and culturally adapted. A professional expert group and five patients evaluated face validity. One hundred and eighty-two patients completed the translated ACL-RSI, a project-specific questionnaire, the Tampa Scale of Kinesiophobia (TSK), the Knee-Self-Efficacy Scale (K-SES), the Multidimensional Health Locus of Control (MHLC-C), the Knee injury and Osteoarthritis Outcome Score (KOOS), and the Anterior Cruciate Ligament-Quality of Life (ACL-QoL) questionnaires. Fifty-three patients answered the ACL-RSI twice to examine reproducibility. The ACL-RSI showed good face validity, internal consistency (Cronbachs alpha=0.948), low floor and ceiling effects and high construct validity when evaluated against the TSK, K-SES, MHLC-C, KOOS, and ACL-QoL scales. The reproducibility was also high (intra-class correlation=0.893). Therefore, the ACL-RSI can be used to evaluate psychological factors relevant to returning to sport after ACL reconstruction surgery.

Background: It is unclear which rehabilitation exercises involve adequate muscle activationwithout excessive anterior tibial translation after ACL reconstruction.

Hypothesis: ACL reconstruction will reduce dynamic tibial translation to the level observedin the uninjured knee. The muscle recruitment pattern will be altered 5 weeks after ACLreconstruction, and some rehabilitation exercises will be more beneficial than others due tovarying amounts of dynamic tibial translation and muscle activation.

Study Design: Descriptive Laboratory Study.

Methods: Sagittal tibial translation and muscle activation were measured with the Lachmantest (static translation) and 7 rehabilitation exercises (dynamic translation) in 19 patients.Results obtained 5 weeks after ACL reconstruction were compared to those obtained beforethe injury (ACL-deficient knee) and in the uninjured knee.

Results: Five weeks after ACL reconstruction the seated knee extension producedsignificantly more anterior tibial translation than the straight leg raise and standing on one leg.The static and dynamic tibial translations measured in ACL reconstructed knees were similarto those measured in uninjured knees. After ACL reconstruction, the patients used a jointstiffening strategy that employed more hamstring activation and reduced the dynamic tibialtranslation.

Conclusions: ACL reconstruction reduced dynamic tibial translation compared to thatobserved before treatment. The muscle recruitment pattern in exercises was altered after ACLreconstruction.

Background: There is no consensus regarding the optimal rehabilitation regimen for increasing quadriceps strength after anterior cruciate ligament (ACL) injury.

Hypothesis: A comprehensive rehabilitation program supplemented with quadriceps strengthening in open kinetic chain (OKC) exercise will increase quadriceps strength and improve knee function without increasing static or dynamic sagittal tibial translation, compared with the same comprehensive rehabilitation program supplemented with quadriceps strengthening in closed kinetic chain (CKC) exercise, in patients with acute ACL deficiency.

Study Design: Randomized controlled trial; Level of evidence, 1.

Methods: Forty-two patients were tested a mean of 43 days (range, 20–96 days) after an ACL injury. Patients were randomized to rehabilitation with CKC quadriceps strengthening (11 men and 9 women) or OKC quadriceps strengthening (13 men and 9 women). Aside from these quadriceps exercises, the 2 rehabilitation programs were identical. Patients were assessed after 4 months of rehabilitation. Sagittal static translation and dynamic tibial translation were evaluated with a CA-4000 electrogoniometer. Muscle strength, jump performance, and muscle activation were also assessed. Functional outcome was evaluated by determining the Lysholm score and the Knee Injury and Osteoarthritis Outcome Score.

Results: There were no group differences in static or dynamic translation after rehabilitation. The OKC group had significantly greater isokinetic quadriceps strength after rehabilitation (P = .009). The hamstring strength, performance on the 1-repetition-maximum squat test, muscle activation, jump performance, and functional outcome did not differ between groups.

Conclusions: Rehabilitation with OKC quadriceps exercise led to significantly greater quadriceps strength compared with rehabilitation with CKC quadriceps exercise. Hamstring strength, static and dynamic translation, and functional outcome were similar between groups. Patients with ACL deficiency may need OKC quadriceps strengthening to regain good muscle torque.

Anterior cruciate ligament injury leads to increased sagittal tibial translation, and perceptions of instability and low confidence in the knee joint are common. Many patients have remaining problems despite treatment and are forced to lower their activity level and prematurely end their career in sports. The effect of ACL reconstruction and/or rehabilitation on dynamic knee stability is not completely understood. The overall aim of this thesis was to study the dynamic knee stability during and after rehabilitation in individuals with ACL injury. More specific aims were 1) to elaborate an evaluation method for muscle strength, 2) to evaluate the effect of exercises in closed and open kinetic chain, and 3) to evaluate dynamic knee stability in patients with ACL deficiency or ACL reconstruction.

Sagittal tibial translation and knee flexion angle were measured using the CA‐4000 computerised goniometer linkage. Muscle activation was registered with electromyography.

The intra‐ and inter‐rater reliability of 1 repetition maximum (RM) of seated knee extension was clinically acceptable. The inter‐rater reliability of 1RM of squat was also acceptable, but the intra‐rater reliability was lower. The systematic procedure for the establishment of 1RM that was developed can be recommended for use in the clinic.

One specific exercise session including cycling and a maximum number of knee extensions and heel raises did not influence static or dynamic sagittal tibial translation in uninjured individuals. A comprehensive rehabilitation program with isolated quadriceps training in OKC led to significantly greater isokinetic quadriceps strength compared to CKC rehabilitation in patients with ACL deficiency. Hamstring strength, static and dynamic translation, and functional outcome were similar between groups. Five weeks after ACL reconstruction, seated knee extension produced more anterior tibial translation compared to the straight leg raise and standing on one leg. All exercises produced less or equal amount of anterior tibial translation as the 90N Lachman test.

Five weeks after the ACL reconstruction the static and dynamic tibial translation in the ACL reconstructed knee did not differ from the tibial translation on the uninjured leg. Patients in the early phase after ACL injury or ACL reconstruction used a joint stiffening strategy including a reduced peak knee extension angle during gait and increased hamstring activation during activity, which reduces the dynamic tibial translation. Patients with ACL deficiency that completed a four months rehabilitation program used a movement pattern that was more close to normal.

Background: After an anterior cruciate ligament injury, the contra-lateral non-injured leg has been found to adapt towards the injured leg. Accordingly, in order to study changes in knee motion pattern after an anterior cruciate ligament injury, the ideal is to compare the same leg prior to and after the injury. However, this is very seldom possible. The purpose of the present study was to describe changes in static and dynamic sagittal tibial translation, electromyographic activity and muscle torque relevant to an anterior cruciate ligament tear in one patient evaluated both before and after the injury.

Methods: A male soccer player was examined 11 weeks before and eight weeks after an anterior cruciate ligament injury. Sagittal tibial translation was measured with the CA-4000 electrogoniometer, statically during Lachman's test, and dynamically during isokinetic muscle testing, one-legged squat and level walking. The electromyographic activity of mm. quadriceps and hamstrings, was registered simultaneously during the one-legged squat test.

Findings: Static tibial translation was increased by ∼2 mm, while dynamic tibial translation was decreased by 0.4 mm at isokinetic testing, 0.9 mm at one-legged squat and 2.4 mm during level walking compared to before the injury. Muscle torque decreased 30% and 35% for the quadriceps and the hamstrings muscle, respectively. The electromyographic activity revealed similar activation levels in quadriceps and a doubled level of activation in hamstring compared to before the injury.

Interpretation: In spite of an increase in static tibial translation eight weeks after an anterior cruciate ligament injury, the tibial translation decreased during activity, thus indicating that the patient could stiffen the knee in order to protect it against increased shear forces.

The purpose of the present study was to develop a systematic procedure for the establishment of 1 repetition maximum (1RM) in order to describe an easily accessible test procedure that is applicable for physical therapists and athletic trainers who manage strength training for healthy individuals and patients. Another purpose was to investigate the intra- and interrater reliability of 1RM of squat on 1 leg and seated knee extension on 1 leg. Estimates of leg strength and ratings of perceived exertion formed the basis of the amount of load selected. The reliability of the procedure was assessed by a test–retest design. One RM was established for 16 and 27 healthy individuals, for squat and knee extension, respectively. The intrarater reliability of 1RM of squat on 1 leg was questionable (intraclass correlation [ICC] 0.64, measurement error 13.1 kg). The interrater reliability of 1RM of squat on 1 leg was clinically acceptable (ICC 0.94, measurement error 5.2 kg). The intrarater and interrater reliability of 1RM of seated knee extension on 1 leg was clinically acceptable (ICC 0.90, measurement error 5.1 kg and ICC 0.96, measurement error 3.2 kg, respectively). In conclusion, both exercises can be used to determine the load in exercise programs. In addition, seated knee extension may be used to evaluate strength. In contrast, squat on 1 leg is more uncertain to use at assessments between different days, which may be due to the complexity of this exercise. The test, performed in the described manner, is suitable for physical therapists, athletic trainers, and strength and conditioning coaches in clinical practice working with strength training and rehabilitation.

No evidence exists that repeated isolated quadriceps contractions lead to increased sagittal plane tibial translation. The purpose was to analyze passive and dynamic tibial translation before, during and after a specific exercise session, including cycling and a maximum number of knee extensions and heel-raises, in healthy individuals. Passive and dynamic sagittal tibial translation was measured on 18 healthy individuals (nine men and nine women) before, during and after a specific exercise session with heavy load, including cycling and maximum number of knee extensions and heel-raises. Sagittal tibial translation during the Lachman test, maximal isometric quadriceps contraction, one-legged squat and gait was registered with the CA-4000 electrogoniometer. The electromyographic (EMG) activity of m. vastus medialis and lateralis, m. gastrocnemius and mm. hamstrings was registered. There was no difference in passive or dynamic sagittal tibial translation during or after the exercise session. No difference could be detected in EMG activity during squat after compared with before the exercise session. In conclusion, the knee exercises did not influence the amount of translation in healthy individuals. The findings indicate that isolated strength training of quadriceps may be included in anterior cruciate ligament rehabilitation programs, even if further specific studies on injured individuals most be performed.