Kati Pasanen

The risk for a cruciate ligament injury of the knee in adolescents and young adults: a population-based cohort study of 46 500 people with a 9 year follow-up

Objectives: The knee joint is the most common site for injury among younger people, the injury often resulting in expensive (surgical) treatment, long-term rehabilitation and permanent functional impairment and disability. Methods: We investigated the incidence and risk factors for a major knee-ligament injury in an adolescent Finnish population. A population-based cohort of 46 472 adolescents was followed for an average of 9 years. All patients hospitalised with the diagnosis of anterior or posterior cruciate ligament injury (ACL or PCL injury) were included in the analysis. Results: 265 (0.6%) people (194 male and 71 female subjects) from the total cohort of 46 472 were treated for a cruciate ligament injury of the knee during the follow-up period, giving an injury incidence of 60.9 (95% CI 53.6 to 68.2) per 100 000 person-years. When the socioeconomic, health and lifestyle background variables were taken into account, the adjusted hazard ratio for a cruciate ligament injury of the knee was 8.5 (95% CI 4.3 to 16.4) for female and 4.0 (95% CI 2.7 to 6.1) for male subjects who participated in organised sports ⩾4 times/week. Conclusions: The general risk for a cruciate ligament injury of the knee is relatively low among adolescents and young adults, but participation in organised sports increases the risk significantly. The risk is especially high in active young women. Preventive measures should be adopted to decrease the short-term and long-term burden of these severe injuries.

Forefoot Strikers Exhibit Lower Running-Induced Knee Loading than Rearfoot Strikers

PURPOSE Knee pain and Achilles tendinopathies are the most common complaints among runners. The differences in the running mechanics may play an important role in the pathogenesis of lower limb overuse injuries. However, the effect of a runners foot strike pattern on the ankle and especially on the knee loading is poorly understood. The purpose of this study was to examine whether runners using a forefoot strike pattern exhibit a different lower limb loading profile than runners who use rearfoot strike pattern. METHODS Nineteen female athletes with a natural forefoot strike (FFS) pattern and pair-matched women with rearfoot strike (RFS) pattern (n = 19) underwent 3-D running analysis at 4 m·s⁻¹. Joint angles and moments, patellofemoral contact force and stresses, and Achilles tendon forces were analyzed and compared between groups. RESULTS FFS demonstrated lower patellofemoral contact force and stress compared with heel strikers (4.3 ± 1.2 vs 5.1 ± 1.1 body weight, P = 0.029, and 11.1 ± 2.9 vs 13.0 ± 2.8 MPa, P = 0.04). In addition, knee frontal plane moment was lower in the FFS compared with heel strikers (1.49 ± 0.51 vs 1.97 ± 0.66 N·m·kg⁻¹, P =0.015). At the ankle level, FFS showed higher plantarflexor moment (3.12 ± 0.40 vs 2.54 ± 0.37 N·m·kg⁻¹; P = 0.001) and Achilles tendon force (6.3 ± 0.8 vs 5.1 ± 1.3 body weight; P = 0.002) compared with RFS. CONCLUSIONS To our knowledge, this is the first study that shows differences in patellofemoral loading and knee frontal plane moment between FFS and RFS. FFS exhibit both lower patellofemoral stress and knee frontal plane moment than RFS, which may reduce the risk of running-related knee injuries. On the other hand, parallel increase in ankle plantarflexor and Achilles tendon loading may increase risk for ankle and foot injuries.

Effect of a neuromuscular warm-up programme on muscle power, balance, speed and agility: a randomised controlled study

Objective: To investigate whether a 6-month neuromuscular warm-up programme could improve muscle power, balance, speed and agility. Design: Cluster randomised controlled study. Setting: 27 top level female floorball teams in Finland. Participants: 222 players (mean age 24 years); 119 in the intervention group and 103 in the control group were followed-up for one league season (6 months). Intervention: A neuromuscular warm-up programme included sports-specific running technique, balance, jumping and strengthening exercises. The teams were advised to use the programme 1–3 times per week through the league season. One training session took ∼25 min. Main outcome measures: Performance tests were assessed before and after the 6-month intervention and included static jump, countermovement jump, jumping over a bar, standing on a bar and figure-of-eight running. Results: At 6 months, significant between-group differences were found in two outcome measures: jumping over a bar (number of jumps in 15 s) and standing on a bar (number of balance losses in 60 s). These differences were 2.3 jumps (95% CI 0.8 to 3.8, p = 0.003), favouring the intervention group, and −0.4 balance losses (95% CI −0.8 to 0.0, p = 0.050), again in favour of the intervention group. Conclusion: A neuromuscular warm-up programme improved the floorball players’ sideways jumping speed and static balance. The exercises were also safe to perform and can thus be recommended for weekly training of floorball players. Trial registration number: ISRCTN26550281.

Stiff Landings Are Associated With Increased ACL Injury Risk in Young Female Basketball and Floorball Players

Background: Few prospective studies have investigated the biomechanical risk factors of anterior cruciate ligament (ACL) injury. Purpose: To investigate the relationship between biomechanical characteristics of vertical drop jump (VDJ) performance and the risk of ACL injury in young female basketball and floorball players. Study Design: Cohort study; Level of evidence, 3. Methods: At baseline, a total of 171 female basketball and floorball players (age range, 12-21 years) participated in a VDJ test using 3-dimensional motion analysis. The following biomechanical variables were analyzed: (1) knee valgus angle at initial contact (IC), (2) peak knee abduction moment, (3) knee flexion angle at IC, (4) peak knee flexion angle, (5) peak vertical ground-reaction force (vGRF), and (6) medial knee displacement. All new ACL injuries, as well as match and training exposure, were then recorded for 1 to 3 years. Cox regression models were used to calculate hazard ratios (HRs) and 95% CIs. Results: Fifteen new ACL injuries occurred during the study period (0.2 injuries/1000 player-hours). Of the 6 factors considered, lower peak knee flexion angle (HR for each 10° increase in knee flexion angle, 0.55; 95% CI, 0.34-0.88) and higher peak vGRF (HR for each 100-N increase in vGRF, 1.26; 95% CI, 1.09-1.45) were the only factors associated with increased risk of ACL injury. A receiver operating characteristic (ROC) curve analysis showed an area under the curve of 0.6 for peak knee flexion and 0.7 for vGRF, indicating a failed-to-fair combined sensitivity and specificity of the test. Conclusions: Stiff landings, with less knee flexion and greater vGRF, in a VDJ test were associated with increased risk of ACL injury among young female basketball and floorball players. However, although 2 factors (decreased peak knee flexion and increased vGRF) had significant associations with ACL injury risk, the ROC curve analyses revealed that these variables cannot be used for screening of athletes.

Predictors of lower extremity injuries in team sports (PROFITS-study): a study protocol

Introduction Several intrinsic risk factors for lower extremity injuries have been proposed, including lack of proper knee and body control during landings and cutting manoeuvres, low muscular strength, reduced balance and increased ligament laxity, but there are still many unanswered questions. The overall aim of this research project is to investigate anatomical, biomechanical, neuromuscular, genetic and demographic risk factors for traumatic non-contact lower extremity injuries in young team sport athletes. Furthermore, the research project aims to develop clinically oriented screening tools for predicting future injury risk. Methods Young female and male players (n=508) from nine basketball teams, nine floorball teams, three ice hockey teams, and one volleyball team accepted the invitation to participate in this four-and-half-year prospective follow-up study. The players entered the study either in 2011, 2012 or 2013, and gave blood samples, performed physical tests and completed the baseline questionnaires. Following the start of screening tests, the players will be followed for sports injuries through December 2015. The primary outcome is a traumatic non-contact lower extremity injury. The secondary outcomes are other sports-related injuries. Injury risk is examined on the basis of anatomical, biomechanical, neuromuscular, genetic and other baseline factors. Univariate and multivariate regression models will be used to investigate association between investigated parameters and injury risk.

Overuse injuries in youth basketball and floorball

Background The popularity of team sports is growing among young people. High training volume and intensity may predispose young athletes to overuse injuries. Research to date has tended to focus on acute injuries rather than overuse injuries. The purpose of this study was to examine the occurrence, nature, and severity of overuse injuries in youth basketball and floorball, with the hypothesis that overuse injuries are frequent in youth team sports. Methods The study comprised a total of 401 Finnish team sports athletes (207 basketball and 194 floorball players). The data were collected using a detailed questionnaire. The participants (mean age 15.8±1.9 years) responded to the questionnaire covering information on overuse injuries during the previous 12 months. Results A total of 190 overuse injuries was reported (97 in basketball and 93 in floorball). In both sports, most of the injuries involved the lower extremities (66% and 55% of all injuries in basketball and floorball, respectively). In basketball, the most commonly injured site was the knee (44 cases, 45%). In floorball, the most commonly injured sites were the lower back/pelvis (36 cases, 39%) and knee (32 cases, 34%). Overuse injuries caused an average time loss from full participation of 26±50 (median 7) days in basketball and 16±37 (median 5) days in floorball. Conclusion Overuse injuries are a common problem in youth team sports, and often cause long-term absence from full participation. The findings suggest that injury reduction and training load monitoring strategies are needed in the field. More research using explicit prospective data collection is needed to better understand the problem.

No association between static and dynamic postural control and ACL injury risk among female elite handball and football players: a prospective study of 838 players

Background Research on balance measures as potential risk factors for ACL injury is limited. Objective To assess whether postural control was associated with an increased risk for ACL injuries in female elite handball and football players. Method Premier league players were tested in the preseason and followed prospectively for ACL injury risk from 2007 through 2015. At baseline, we recorded player demographics, playing experience, ACL and ankle injury history. We measured centre of pressure velocity in single-leg stabilisation tests and reach distances in the Star Excursion Balance Test. To examine the stability of postural control measures over time, we examined their short-term and long-term reproducibility. We generated logistic regression models, 1 for each of the proposed risk factors. Results A total of 55 (6.6%) out of 838 players (age 21±4 years; height 170±6 cm; body mass 66±8 kg) sustained a non-contact ACL injury after baseline testing (1.8±1.8 years). When comparing normalised balance measures between injured and uninjured players in univariate analyses, none of the variables were statistically associated with ACL injury risk. Short-term and long-term reproducibility of the selected variables was poor. Players with a previous ACL injury had a 3-fold higher risk of sustaining a new ACL injury compared with previously uninjured players (OR 2.9, CI 1.4 to 5.7). Conclusions None of postural control measures examined were associated with increased ACL injury risk among female elite handball and football players. Hence, as measured in the current investigation, the variables included cannot be used to predict ACL injury risk.

Epidemiology of Overuse Injuries in Youth Team Sports: A 3-year Prospective Study

Prospective studies on overuse injuries and their impact on athletic training among youth team sports are scarce. The purpose of this study was to investigate the incidence, severity and player related risk factors of overuse injuries among young (12-20 years) basketball and floorball players. A total of 387 players participated in a 3-year prospective study. Each player completed a baseline questionnaire regarding their background information. Overuse injuries that prevented players to fully or partly participate in their regular training were collected. In all, 204 overuse injuries were registered (injury incidence 1.51 injuries/1 000 h of exposure; 95% CI 1.35-1.78). Most of the injuries involved the knee (35%) and lower back (21%), and were classified as severe (44%). Injury incidence was 1.51 (95% CI 1.2-1.82) and 1.61 (95% CI 1.32-1.91) in basketball and floorball, respectively. Incidence was significantly higher among female compared with male players (incidence rate ratio 1.58; 95% CI 1.20-2.09). Previous injury and playing at adult level were the strongest factors associated with occurrence of an overuse injury. In conclusion, overuse injuries of the knee and low back are relatively common in youth basketball and floorball. Effective prevention strategies as well as training load monitoring is needed in youth team sports.

Acute injuries in Finnish junior floorball league players

OBJECTIVES To investigate the incidence and characteristics of acute time-loss injuries in Finnish junior floorball league players. DESIGN Prospective cohort study with 3-year follow-up. METHODS One hundred and eighty-six female and male players (mean age 16.6±1.4) took part in the follow-up study (2011-2014). The training hours and games were recorded on a team diary. Floorball related acute injuries were registered and verified by a research physician. The injury incidence was expressed as the number of injuries per 1000h of exposure. Incidence rate was calculated separately for games and practices, and for males and females. RESULTS One hundred and forty-four acute time-loss injuries occurred. Injury incidence was 26.87 (95% CI 20.10-33.63) in junior league games, and 1.25 (95% CI 0.99-1.52) in team practices. Female players had significantly higher game injury rate (IRR 1.88, 1.12-3.19) and joint/ligament injury rate (IRR 1.70, 1.07-2.73) compared to males. Eighty-one percent of the injuries affected the lower limbs. The ankle (37%), knee (18%), and thigh (14%) were the most commonly injured body sites. More than half of injuries involved joint or ligaments (54%). Twenty-six percent of the injuries were severe causing more than 28days absence from sports. Eight anterior cruciate ligament ruptures of the knee occurred among seven female players. CONCLUSION The study revealed that risk of ankle and knee ligament injuries is high in adolescent floorball, specifically among female players.

Association between frontal plane knee control and lower extremity injuries : a prospective study on young team sport athletes

Background/aim Poor frontal plane knee control can manifest as increased dynamic knee valgus during athletic tasks. The purpose of this study was to investigate the association between frontal plane knee control and the risk of acute lower extremity injuries. In addition, we wanted to study if the single-leg squat (SLS) test can be used as a screening tool to identify athletes with an increased injury risk. Methods A total of 306 basketball and floorball players participated in the baseline SLS test and a 12-month injury registration follow-up. Acute lower extremity time-loss injuries were registered. Frontal plane knee projection angles (FPKPA) during the SLS were calculated using a two-dimensional video analysis. Results Athletes displaying a high FPKPA were 2.7 times more likely to sustain a lower extremity injury (adjusted OR 2.67, 95% CI 1.23 to 5.83) and 2.4 times more likely to sustain an ankle injury (OR 2.37, 95% CI 1.13 to 4.98). There was no statistically significant association between FPKPA and knee injury (OR 1.49, 95% CI 0.56 to 3.98). The receiver operating characteristic curve analyses indicated poor combined sensitivity and specificity when FPKPA was used as a screening test for lower extremity injuries (area under the curve of 0.59) and ankle injuries (area under the curve of 0.58). Conclusions Athletes displaying a large FPKPA in the SLS test had an elevated risk of acute lower extremity and ankle injuries. However, the SLS test is not sensitive and specific enough to be used as a screening tool for future injury risk.