Specific exercise effects of preventive neuromuscular training intervention on anterior cruciate ligament injury risk reduction in young females: meta-analysis and subgroup analysis

Neuromuscular Training Availability and Efficacy in Preventing Anterior Cruciate Ligament Injury in High School Sports: A Retrospective Cohort Study

OBJECTIVE

To document neuromuscular training (NMT) availability and its relationship to anterior cruciate ligament (ACL) injuries in 4 major high school sports by gender, sport, and rural/urban geography, with the hypothesis that increased exposure to NMT would be associated with fewer ACL injuries.

DESIGN

A retrospective cohort study.

SETTING

All Minnesota high schools identified in the Minnesota State High School League (MSHSL) database for fall 2014 boys' football and soccer, and girls' volleyball and soccer.

PARTICIPANTS

All high school athletic directors were surveyed to report their school's fall 2014 experience; 53.5% returned the survey reporting experience with one or more of the sports.

INTERVENTION

Athletic directors documented each sport's preseason and in-season exposure to NMT (plyometric exercises, proximal/core muscle strengthening, education and feedback regarding proper body mechanics, and aerobics) and licensed athletic trainers.

MAIN OUTCOMES

Reported ACL injuries by sport, gender and rural/urban.

RESULTS

More than two-thirds of teams incorporated facets of NMT into their sport. Among male athletes, soccer players exposed to licensed athletic trainers experienced significantly fewer ACL injuries (P < 0.005), and NMT was associated with significantly fewer ACL injuries in football (P < 0.05) and soccer (P < 0.05). Female athletes did not demonstrate similar associated improvements, with volleyball injuries associated with increased NMT (P < 0.001), and soccer injuries not associated with NMT. However, girl soccer players in rural settings reported fewer ACL injures compared with urban teams (P < 0.001).

CONCLUSIONS

Most fall high school sports teams were exposed to NMT, which was associated with fewer ACL injuries for male, but not for female athletes. Improved gender- and sport-specific preventive training programs are indicated.

Dissemination and Implementation Strategies of Lower Extremity Preventive Training Programs in Youth: A Clinical Review

Context:

Neuromuscular preventive training programs effectively reduce injury and improve performance in youth athletes. However, program effectiveness is directly linked to program compliance, fidelity, and dosage. Preventive training programs are not widely adopted by youth sport coaches. One way to promote widespread dissemination and compliance is to identify implementation strategies that influence program adoption and maintenance. It is unknown how previously published programs have followed the elements of an implementation framework. The objective of this review was to evaluate how elements of the 7 steps of implementation, developed by Padua et al, have been performed in the evidence of lower extremity preventive training programs.

Evidence Acquisition:

A systematic review of the literature from 1996 through September 2016 was conducted using electronic databases. Investigations that documented implementation of a sport team-based neuromuscular preventive training program in youth athletes and measured lower extremity injury rates were included.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

A total of 12 studies met the inclusion criteria and were reviewed. Information regarding the completion of any of the 7 steps within the implementation framework developed by Padua et al was extracted. None of the 12 articles documented completion of all 7 steps. While each study addressed some of the 7 steps, no study addressed maintenance or an exit strategy for youth athletes. Program implementation appears limited in obtaining administrative support, utilizing an interdisciplinary implementation team, and monitoring or promoting fidelity of the intervention.

Conclusion:

Despite strong evidence supporting the effectiveness of preventive training programs in youth athletes, there is a gap between short-term improvements and long-term implementation strategies. Future interventions should include all 7 steps of the implementation framework to promote transparent dissemination of preventive training programs.

Report of the Clinical and Functional Primary Outcomes in Men of the ACL-SPORTS Trial: Similar Outcomes in Men Receiving Secondary Prevention With and Without Perturbation Training 1 and 2 Years After ACL Reconstruction

BACKGROUND

Athletes often are cleared to return to activities 6 months after anterior cruciate ligament (ACL) reconstruction; however, knee function measures continue to improve up to 2 years after surgery. Interventions beyond standard care may facilitate successful return to preinjury activities and improve functional outcomes. Perturbation training has been used in nonoperative ACL injury and preoperative ACL reconstruction rehabilitation, but has not been examined in postoperative ACL reconstruction rehabilitation, specifically return to sport rehabilitation.

QUESTIONS/PURPOSES

The purpose of this study was to determine whether there were differences at 1 and 2 years after ACL reconstruction between the male SAP (strengthening, agility, and secondary prevention) and SAP+PERT (SAP protocol with the addition of perturbation training) groups with respect to (1) quadriceps strength and single-legged hop limb symmetry; (2) patient-reported knee outcome scores; (3) the proportion who achieve self-reported normal knee function; and (4) the time from surgery to passing return to sport criteria.

METHODS

Forty men who had completed ACL reconstruction rehabilitation and met enrollment criteria (3-9 months after ACL reconstruction, > 80% quadriceps strength limb symmetry, no pain, full ROM, minimal effusion) were randomized into the SAP or SAP+PERT groups of the Anterior Cruciate Ligament-Specialised Post-Operative Return to Sports trial (ACL-SPORTS), a single-blind randomized clinical study of secondary prevention and return to sport. Quadriceps strength, single-legged hopping, the International Knee Documentation Committee (IKDC) 2000 subjective knee form, Knee Injury and Osteoarthritis Outcome Score (KOOS)-sports and recreation, and KOOS-quality-of-life subscales were collected 1 and 2 years after surgery by investigators blind to group. Athletes were categorized as having normal or abnormal knee function at each time point based on IKDC score, and the time until athletes passed strict return-to-sport criteria was also recorded. T-tests, chi square tests, and analyses of variance were used to identify differences between the treatment groups over time.

RESULTS

There were no differences between groups for quadriceps symmetry (1 year: SAP = 101% ± 14%, SAP+PERT = 101% ± 14%; 2 years: SAP = 103% ± 11%, SAP+PERT = 98% ± 14%; mean differences between groups at 1 year: 0.4 [-9.0 to 9.8], 2 years = 4.5 [-4.3 to 13.1]; mean difference between 1 and 2 years: SAP = -1.0 [-8.6 to 6.6], SAP+PERT = 3.0 [-4.3 to 10.3], p = 0.45) or single-legged hop test limb symmetry. There were no clinically meaningful differences for any patient-reported outcome measures. There was no difference in the proportion of athletes in each group who achieved normal knee function at 1 year (SAP 14 of 19, SAP+PERT 18 of 20, odds ratio 0.31 [0.5-19.0]; p = 0.18); however, the SAP+PERT group had fewer athletes with normal knee function at 2 years (SAP 17 of 17, SAP+PERT 14 of 19, p = 0.03). There were no differences between groups in the time to pass return to sport criteria (SAP = 325 ± 199 days, SAP+PERT = 233 ± 77 days; mean difference 92 [-9 to 192], p = 0.09).

CONCLUSIONS

This randomized trial found few differences between an ACL rehabilitation program consisting of strengthening, agility, and secondary prevention and one consisting of those elements as well as perturbation training. In the absence of clinically meaningful differences between groups in knee function and self-reported outcomes measures, the results indicate that perturbation training may not contribute additional benefit to the strengthening, agility, and secondary prevention base of the ACL-SPORTS training program.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Multiligament Knee Injuries in Older Adolescents: A 2-Year Minimum Follow-up Study

Background:

Multiligament knee injuries cause significant functional impairment. Adults undergoing anatomic reconstruction of multiligament knee injuries have excellent outcomes postoperatively. However, less is known about the outcomes in adolescent patients following multiligament reconstruction.

Purpose/Hypothesis:

We aimed to assess patient outcomes and failure rates following unstaged multiligament reconstruction in an adolescent population at a minimum 2-year follow-up. We hypothesized that outcomes of multiligament reconstruction in these patients would be comparable to previously reported outcomes in the adult population.

Study Design:

Case series; Level of evidence, 4.

Methods:

The study included patients who had undergone multiligament knee reconstruction at 19 years of age or younger and had at least 2 years of follow-up. All procedures were performed by the same surgeon. Exclusion criteria included patient age 14 years or younger at the time of surgery, open physes, prior ipsilateral meniscal or knee ligament surgery, or a tibial plateau fracture at the time of injury. Multiligament reconstruction was defined as a reconstruction of at least 1 cruciate ligament and at least 1 component of the posterolateral corner or the medial knee. Patients were evaluated according to Lysholm score, Tegner score, Short Form–12 physical component summary (SF-12 PCS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and postoperative patient satisfaction.

Results:

Twenty patients (mean age, 17.7 years; mean follow-up, 37.1 months) were included in this study. No patient required additional ligament surgery after the index surgery because of graft failure. The median preoperative Lysholm score was 49.5 (range, 18-90), and the median postoperative Lysholm score was 86 (range, 44-100) (P < .001). The median preoperative Tegner activity score was 2 (range, 0-9), and the median postoperative Tegner activity score was 6 (range, 2-10) (P = .012). The median SF-12 PCS improved from 40.5 preoperatively to a median of 56.1 postoperatively (P < .001). WOMAC total score improved from a median of 26.5 preoperatively to a median of 2 postoperatively (P < .001). Median postoperative patient satisfaction was 10 (range, 5-10).

Conclusion:

Single-stage multiligament knee reconstruction is a reliable procedure that improves knee function at 2-year follow-up in adolescent patients. Patient satisfaction was excellent, but longer follow-up in a larger series of patients is required to determine the long-term benefits of multiligament reconstruction in this patient population.

Osteoarthritis action alliance consensus opinion - best practice features of anterior cruciate ligament and lower limb injury prevention programs

AIM

To identify best practice features of an anterior cruciate ligament (ACL) and lower limb injury prevention programs (IPPs) to reduce osteoarthritis (OA).

METHODS

This consensus statement started with us performing a systematic literature search for all relevant articles from 1960 through January 2017 in PubMed, Web of Science and CINAHL. The search strategy combined the Medical Subject Heading (MeSH) and keywords for terms: (1) ACL OR “knee injury” OR “anterior cruciate ligament”; (2) “prevention and control” OR “risk reduction” OR “injury prevention” OR “neuromuscular training”; and (3) meta-analysis OR “systematic review” OR “cohort study” OR randomized. We found 166 different titles. The abstracts were reviewed for pertinent papers. The papers were reviewed by at least two authors and consensus of best practice for IPP to prevent OA was obtained by conference calls and e-mail discussions. All authors participated in the discussion.

RESULTS

The best practice features of an IPP have the following six components: (1) lower extremity and core strengthening; (2) plyometrics; (3) continual feedback to athletes regarding proper technique; (4) sufficient dosage; (5) minimal-to-no additional equipment; and (6) balance training to help prevent injuries. Exercises focused on preventing ankle sprains, hamstring injuries and lateral trunk movements are important. Plyometric exercises should focus on correcting knee valgus movement. Exercises should focus on optimizing the hamstring to quadriceps strength ratio. In order for IPP to be successful, there should be increased education and verbal feedback along with increased athletic compliance. Additional equipment is not necessary. Balance training alone does not significantly reduce injuries, but is beneficial with other exercises. Not enough evidence to recommend stretching and agility exercises, with no ill effects identified. Therefore, we suggest making these optional features.

CONCLUSION

Best practice features for ACL and lower limb IPPs to help prevent OA contain six key components along with two optional.

Incidence of Second Anterior Cruciate Ligament Tears and Identification of Associated Risk Factors From 2001 to 2010 Using a Geographic Database

BACKGROUND

The reported rate of second anterior cruciate ligament (ACL) injuries (20%-30%), including graft failure and contralateral ACL tears, after ACL reconstruction (ACLR) or nonoperative therapy indicates that multiple factors may predispose patients to subsequent ACL injuries.

PURPOSE

To determine the incidence of second ACL injuries in a population-based cohort over a 10-year observation period (2001-2010) and to identify factors that contribute to the risk of second injuries.

STUDY DESIGN

Descriptive epidemiological study.

METHODS

International Classification of Diseases, 9th Revision (ICD-9) codes relevant to the diagnosis of an ACL tear and the procedure code for ACLR were utilized to search the Rochester Epidemiology Project, a multidisciplinary county database, between the years of 2001 and 2010. The complete medical records for all cases were reviewed to confirm diagnosis and treatment details. A total of 914 unique patients with 1019 acute, isolated ACL tears were identified. These patients were stratified by primary and secondary tears, sex, age, activity level, side of injury, sex × side of injury, and graft type of reconstruction.

RESULTS

Second ACL tears were recorded in 141 (13.8%) of the 914 patients diagnosed with an ACL tear in Olmsted County, Minnesota, USA, from 2001 to 2010; 50.4% of these occurred in the contralateral knee. A noncontact mechanism was responsible for 76.4% of all ACL injuries. A second ACL injury was influenced by factors of sex × age group, treatment type × age group, and treatment type × activity level. Nonparametric analysis of graft disruption × graft type demonstrated that a higher prevalence of second ACL tears occurred with allografts compared with hamstring autografts (P = .0054) and patellar tendon autografts (P = .0001).

CONCLUSION

The incidence of second ACL tears in this population-based cohort was 13.8%, and half occurred to the ACL of the contralateral knee. Statistically, second ACL injuries differed by sex, occurring in female patients younger than 25 years and male patients aged 26 to 45 years. Allografts continued to be associated with a greater risk of second ACL injuries compared with hamstring and patellar tendon autografts. Nonoperative treatment carried more risk of contralateral tears than ACLR.

Avulsion of the Anterior Inferior Iliac Spine Rehabilitation in a Rural Private Practice

An unusual case is presented of an 11-year-old girl presenting for treatment to a semirural private physical therapy practice, not specializing in pediatric care, following an avulsion fracture of the anterior inferior iliac spine. The patient presented initially non-weight-bearing, with little hip movement due to pain. Following treatment, the patient returned to preinjury status including return to full participation in netball. A review of the literature regarding healing and rehabilitation is described. Concepts of neuromuscular retraining were integrated in the rehabilitation program. Recent evidence demonstrates deficiencies in hip and knee control for girls between 11 and 15 years of age. Evidence suggests that these deficiencies may be a precursor to injury and poor outcomes in lower extremity injuries in this patient group.

Prevention, treatment, and rehabilitation of anterior cruciate ligament injuries in children

As more children and adolescents participate in competitive organized sports, there has been an increase in the reported incidence of anterior cruciate ligament (ACL) injuries in these age groups. ACL injuries in skeletally immature athletes present a challenge, as reconstruction must preserve the physis of the distal femur and of the proximal tibia to avoid growth disturbances. Historically, a skeletally immature athlete with an ACL injury was treated with a brace and activity modification until skeletal maturity, with ACL reconstruction being performed at that time in the “non-copers” who experienced instability. More recently, evidence has shown that delayed reconstruction may lead to increased damage to the meniscus and articular cartilage. As a result, early reconstruction is favored to protect the meniscus and allow continued physical activity. While adolescents at or those near skeletal maturity may be treated with standard reconstruction techniques, they may result in growth disturbances in younger athletes with significant growth remaining. In response to the growing need for ACL reconstruction techniques in skeletally immature individuals, physeal-sparing and physeal-respecting reconstruction techniques have been developed. In addition to the advancements in surgical technique, ACL injury prevention has also gained attention. This growing interest in ACL prevention is in part related to the high risk of ACL re-tear, either of the ACL graft or of the contralateral ACL, in children and adolescents. Recent reports indicate that well-designed neuromuscular training programs may reduce the risk of primary and subsequent ACL injuries.

Effects of a dynamic core stability program on the biomechanics of cutting maneuvers: A randomized controlled trial

Deficits in trunk control predict ACL injuries which frequently occur during high-risk activities such as cutting. However, no existing trunk control/core stability program has been found to positively affect trunk kinematics during cutting activities. This study investigated the effectiveness of a 6-week dynamic core stability program (DCS) on the biomechanics of anticipated and unanticipated side and crossover cutting maneuvers. Thirty-one male, varsity footballers participated in this randomized controlled trial. Three-dimensional trunk and lower limb biomechanics were captured in a motion analysis laboratory during the weight acceptance phase of anticipated and unanticipated side and crossover cutting maneuvers at baseline and 6-week follow-up. The DCS group performed a DCS program three times weekly for 6 weeks in a university rehabilitation room. Both the DCS and control groups concurrently completed their regular practice and match play. Statistical parametric mapping and repeated measures analysis of variance were used to determine any group (DCS vs control) by time (pre vs post) interactions. The DCS resulted in greater internal hip extensor (P=.017, η² =0.079), smaller internal knee valgus (P=.026, η² =0.076), and smaller internal knee external rotator moments (P=.041, η² =0.066) during anticipated side cutting compared with the control group. It also led to reduced posterior ground reaction forces for all cutting activities (P=.015-.030, η² =0.074-0.105). A 6-week DCS program did not affect trunk kinematics, but it did reduce a small number of biomechanical risk factors for ACL injury, predominantly during anticipated side cutting. A DCS program could play a role in multimodal ACL injury prevention programs.

Incidence of Second Anterior Cruciate Ligament Tears (1990-2000) and Associated Factors in a Specific Geographic Locale

BACKGROUND

Second anterior cruciate ligament (ACL) tears after reconstruction occur at a reported rate of 20% to 30%. This high frequency indicates that there may be factors that predispose an athlete to graft failure and ACL tears of the contralateral knee.

PURPOSE

To determine the incidence of second ACL injuries in a geographic population-based cohort over a 10-year observation period.

STUDY DESIGN

Descriptive epidemiological study.

METHODS

International Classification of Diseases, 9th Revision (ICD-9) codes relevant to the diagnosis of an ACL tear and the procedure code for ACL reconstruction were searched across the Rochester Epidemiology Project, a multidisciplinary county database, between the years of 1990 and 2000. This cohort of patients was tracked for subsequent ACL injuries through December 31, 2015. The authors identified 1041 patients with acute, isolated ACL tears. These patients were stratified by primary and secondary tears, sex, age, activity level, side of injury, sex by side of injury, and graft type.

RESULTS

Of the 1041 unique patients with a diagnosed ACL tear in Olmsted County, Minnesota, from 1990 to 2000, there were 66 (6.0%) second ACL tears; 66.7% of these tears occurred on the contralateral side. A second ACL injury was influenced by graft type ( P < .0001), election of ACL reconstruction ( P = .0060), and sex by side of injury ( P = .0072). Nonparametric analysis of graft disruption by graft type demonstrated a higher prevalence of second ACL tears with allografts compared with hamstring ( P = .0499) or patellar tendon autografts ( P = .0012).

CONCLUSION

The incidence of second ACL tears in this population-based cohort was 6.0%, with 66.7% of these tears occurring on the contralateral side from the original injury. There was a high population incidence of second ACL injuries in female patients younger than age 20 years. The utilization of patellar tendon autografts significantly reduced the risk of second ACL injuries compared with allografts or hamstring autografts in this cohort.

Resistance Training in Youth: Laying the Foundation for Injury Prevention and Physical Literacy

CONTEXT

The rising incidence of physical activity- and sports-related injuries has prompted the present-day investigation of resistance training as a potential means of injury prevention and physical literacy development among youth.

EVIDENCE ACQUISITION

Relevant studies on the topics of athlete development, physical literacy, resistance training, and injury prevention in children and adolescents were reviewed (PubMed and Sports Discus, 1982-2016). Recommendations from consensus guidelines and position statements applicable to resistance training and injury prevention in youth, in addition to young athlete development, were reviewed. Additionally, hand searches, expert requests, article reference lists, and gray literature were utilized and reviewed for pertinent content.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Youth throughout the physical activity spectrum are at risk for physical activity- and sports-related injury. Of highest priority are early specializers, physically inactive youth, and young girls, owing to increased injury rates. Resistance training among these at-risk populations has been shown to reduce injury risk by up to 68% and improve sports performance and health measures, in addition to accelerating the development of physical literacy. Recent recommendations, position statements, and national initiatives advocate for the incorporation of resistance training with qualified instruction among these groups.

CONCLUSION

Resistance training in addition to free play and other structured physical activity training can serve as a protective means against injury and a positive catalyst for the development of physical literacy to offset the impact of diminishing physical activity and early sport specialization in today's youth.

Injury Prevention in Youth Sports

Children and adolescents are now participating in competitive sports at younger ages and with increasing intensity. As a result, increasing numbers of young athletes are presenting to pediatricians for care of sports-related injuries and advice about prevention. Understanding and identifying modifiable risk factors for injury in the young athletic population is a critical first step in injury prevention. Risk factors vary by sport, age, and sex. This article reviews the most common risk factors for injury and the evidence to support proposed strategies for prevention. [Pediatr Ann. 2017;46(3):e99-e105.].

Neuroscience Application to Noncontact Anterior Cruciate Ligament Injury Prevention

Context:

Many factors, including anatomy, neuromuscular control, hormonal regulation, and genetics, are known to contribute to the noncontact anterior cruciate ligament (ACL) injury risk profile. The neurocognitive and neurophysiological influences on the noncontact ACL injury mechanism have received less attention despite their implications to maintain neuromuscular control. Sex-specific differences in neurocognition may also play a critical role in the elevated female ACL injury risk. This report serves to frame existing literature in a new light to consider neurocognition and its implications for movement control, visual-motor function, and injury susceptibility.

Evidence Acquisition:

Sources were obtained from PubMed, MEDLINE, Web of Science, and LISTA (EBSCO) databases from 1990 onward and ranged from diverse fields including psychological and neuroscience reviews to injury epidemiology and biomechanical reports.

Study Design:

Clinical review.

Level of Evidence:

Level 5.

Results:

Neurological factors may contribute to the multifactorial ACL injury risk paradigm and the increased female injury susceptibility.

Conclusion:

When developing ACL injury prevention programs, considering neurocognition and its role in movement, neuromuscular control, and injury risk may help improve intervention effectiveness.

Critical components of neuromuscular training to reduce ACL injury risk in female athletes: meta-regression analysis

OBJECTIVE

The aim of this study was to determine key components in neuromuscular training that optimise ACL injury reduction in female athletes using meta-regression analyses.

DESIGN

Systematic review and meta-regression.

DATA SOURCES

The literature search was performed in PubMed and EBSCO.

ELIGIBILITY CRITERIA

Inclusion criteria for the current analysis were: (1) documented the number of ACL injuries, (2) employed a neuromuscular training intervention that aimed to reduce ACL injuries, (3) had a comparison group, (4) used a prospective control study design and (5) recruited female athletes as participants. Two independent reviewers extracted studies which met the inclusion criteria. Methodological quality of included study and strength of recommendation were evaluated. Number of ACL injuries and participants in control and intervention groups, age of participants, dosage of neuromuscular training, exercise variations within neuromuscular training and status of verbal feedback were extracted.

RESULTS

The meta-regression analyses identified age of participants, dosage of neuromuscular training, exercise variations within neuromuscular training and utilisation of verbal feedback as significant predictors of ACL injury reduction (p=0.01 in fixed-effects model, p=0.03 in random-effects model). Inclusion of 1 of the 4 components in neuromuscular training could reduce ACL injury risk by 17.2-17.7% in female athletes. No significant heterogeneity and publication bias effects were detected. Strength of recommendation was rated as A (recommendation based on consistent and good-quality patient-oriented study evidence).

CONCLUSIONS

Age of participants, dosage of neuromuscular training, exercise variations within neuromuscular training and utilisation of verbal feedback are predictors that influence the optimisation of prophylactic effects of neuromuscular training and the resultant ACL injury reduction in female athletes.

Changes in Knee Osteoarthritis, Symptoms, and Function After Anterior Cruciate Ligament Reconstruction: A 20-Year Prospective Follow-up Study

BACKGROUND

Progression of tibiofemoral (TF) and patellofemoral (PF) osteoarthritis (OA) and changes in knee function more than 15 years after anterior cruciate ligament reconstruction (ACLR) are not well understood.

PURPOSE

To examine the progression of knee OA and changes in symptoms and function in isolated and combined injuries from 15 to 20 years after ACLR.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 210 subjects with ACLR were prospectively followed. At the 15- and 20-year follow-ups, radiographs were obtained and classified by the Kellgren and Lawrence (K-L) grading system. Symptoms and function were evaluated with the Knee injury and Osteoarthritis Outcome Score (KOOS) as well as isokinetic quadriceps and hamstring muscle strength tests.

RESULTS

There were 168 subjects (80%) who returned for the 20-year follow-up, with a mean (±SD) age of 45 ± 9 years, mean body mass index of 27 ± 4, and median Tegner activity level of 4 (range, 0-9). The prevalence of radiographic TF and PF OA at the 20-year follow-up was 42% and 21%, respectively. Patients with ACL injuries and other combined injuries had significantly higher prevalence of radiographic TF OA compared with those who had isolated ACL injury (P < .0001). There was a 13% increase in radiographic TF OA (P = .001) and an 8% increase in PF OA (P = .015) from the 15- to the 20-year follow-up. A significant deterioration in knee symptoms and function was observed on the KOOS subscales (P ≤ .01), with the exception of quality of life (P = .14), as well as a decrease in quadriceps muscle strength and hamstring muscle strength (P < .0001).

CONCLUSION

The prevalence of radiographic TF and PF OA was 42% and 21%, respectively. A significantly higher prevalence of TF OA was found for subjects with combined injuries compared with those who had isolated ACL injury. The majority of the subjects were stable radiographically over the 5 years between follow-ups. A statistically significant deterioration in symptoms and function was noted, but the mean changes were of questionable clinical importance.

Osteoarthritis and the Tactical Athlete: A Systematic Review

OBJECTIVE

 Although tactical athletes (eg, military service members, law enforcement personnel, fire fighters) are exposed to several known risk factors, it remains unclear if they are at increased risk for osteoarthritis (OA). The purpose of this systematic review was to investigate the association between serving as a tactical athlete and the incidence and prevalence of OA.

DATA SOURCES

 We completed a comprehensive systematic literature search in November 2014 using 12 bibliographic databases (eg, PubMed, Ovid, SportDiscus) supplemented with manual searches of reference lists.

STUDY SELECTION

 Studies were included if they met the following criteria: (1) an aim of the study was to investigate an association between tactical athletes and OA; (2) the outcome measure was radiographic OA, clinical OA, total joint replacement, self-reported diagnosis of OA, or placement on a waiting list for a total joint replacement; (3) the study design was a cohort study; and (4) the study was written in English.

DATA EXTRACTION

 One investigator extracted data from articles that met all inclusion criteria (eg, group descriptions, measures of disease burden, source of nonexposed controls).

DATA SYNTHESIS

 Twelve articles met the inclusion criteria and described retrospective cohort studies. Firefighters, active-duty military service members, and veteran military parachutists consistently had a higher incidence or prevalence of knee, hip, or any OA diagnosis (4 studies). Active-duty pilots and veteran military parachutists may have a higher prevalence of spine OA, but this was not statistically significant (2 studies). Occupational risk factors for OA among tactical athletes include rank and branch of military service. The risk of OA among individuals who completed mandatory national military service remains unclear (6 studies).

CONCLUSIONS

 The incidence of OA among tactical athletes appears to be significantly higher when compared with nonexposed controls. Further research is needed to specifically identify modifiable risk factors within this high-risk population to develop and implement effective risk-reduction strategies.

Knee and Hip Joint Kinematics Predict Quadriceps and Hamstrings Neuromuscular Activation Patterns in Drop Jump Landings

Purpose

The purpose was to assess if variation in sagittal plane landing kinematics is associated with variation in neuromuscular activation patterns of the quadriceps-hamstrings muscle groups during drop vertical jumps (DVJ).

Methods

Fifty female athletes performed three DVJ. The relationship between peak knee and hip flexion angles and the amplitude of four EMG vectors was investigated with trajectory-level canonical correlation analyses over the entire time period of the landing phase. EMG vectors consisted of the {vastus medialis(VM),vastus lateralis(VL)}, {vastus medialis(VM),hamstring medialis(HM)}, {hamstring medialis(HM),hamstring lateralis(HL)} and the {vastus lateralis(VL),hamstring lateralis(HL)}. To estimate the contribution of each individual muscle, linear regressions were also conducted using one-dimensional statistical parametric mapping.

Results

The peak knee flexion angle was significantly positively associated with the amplitudes of the {VM,HM} and {HM,HL} during the preparatory and initial contact phase and with the {VL,HL} vector during the peak loading phase (p<0.05). Small peak knee flexion angles were significantly associated with higher HM amplitudes during the preparatory and initial contact phase (p<0.001). The amplitudes of the {VM,VL} and {VL,HL} were significantly positively associated with the peak hip flexion angle during the peak loading phase (p<0.05). Small peak hip flexion angles were significantly associated with higher VL amplitudes during the peak loading phase (p = 0.001). Higher external knee abduction and flexion moments were found in participants landing with less flexed knee and hip joints (p<0.001).

Conclusion

This study demonstrated clear associations between neuromuscular activation patterns and landing kinematics in the sagittal plane during specific parts of the landing. These findings have indicated that an erect landing pattern, characterized by less hip and knee flexion, was significantly associated with an increased medial and posterior neuromuscular activation (dominant hamstrings medialis activity) during the preparatory and initial contact phase and an increased lateral neuromuscular activation (dominant vastus lateralis activity) during the peak loading phase.

Contrasting effects of a mixed-methods high-intensity interval training intervention in girl football players

Little is known about the responses of girl athletes to training interventions throughout maturation. This study evaluated group and individual responses to an 8-week, mixed-methods, high-intensity interval training (HIIT) programme in girl football players. Thirty-seven players (age 13.4 ± 1.5 years) were tested for 20-m speed, repeated-sprint ability, change-of-direction speed and level 1 yo-yo intermittent recovery (YYIR). Players were subcategorised into before-, at- and after-PHV (peak height velocity) based on maturity offset. Very likely moderate (25%; ±90% confidence limits = 9.2) improvements occurred in YYIR, but data were unclear in players before-PHV with moderate individual differences in response. Decrements in repeated-sprint ability were most likely very large (6.5%; ±3.2) before-PHV, and likely moderate (1.7%; ±1.0) at-PHV. Data were unclear after-PHV. A very likely moderate (2.7%; ±1.0) decrement occurred in change-of-direction speed at-PHV while there was a very likely increase (-2.4%; ±1.3) in after-PHV players. Possibly small (-1.1%; ±1.4) improvements in 20-m speed occurred before-PHV but the effect was otherwise unclear with moderate to large individual differences. These data reflect specific responses to training interventions in girls of different biological maturity, while highlighting individual responses to HIIT interventions. This can assist practitioners in providing effective training prescription.

ACL injury in football: a literature overview of the prevention programs

BACKGROUND

The ACL prevention programs are addressed to the control and/or modification of the so-called "modifiable risk factors". All these programs focus on different intervention strategies aimed to decrease the ACL injury risk, particularly in female athletes population.

PURPOSE

To furnish an overview of the most used ACL injury prevention program through a narrative review.

CONCLUSION

In literature there are many reports on prevention programs whose common denominator is the proper alignment of the lower limb joints and proper motor control during movements that are considered at risk for ACL integrity, as the landing phase after a jump. Nevertheless, some programs would appear more effective than others. In any cases a major problem remains the lack of sufficient compliance in respect of prevention programs. Finally, it is important to remember that the ethiology of ACL injuries is multifactorial. For this reason a prevention program able to prevent all the risk situations is utopian.

STUDY DESIGN

Narrative review.

ABCs of Evidence-based Anterior Cruciate Ligament Injury Prevention Strategies in Female Athletes

Anterior cruciate ligament (ACL) injury is a major concern in physically active females. Although ACL reconstruction techniques have seen significant advances in recent years, risk associated with re-injury and future osteoarthritis remains a major concern. Thus, prevention of ACL injury is a logical step to protect and preserve healthy knee joints in young athletes. The current report aims to summarize a list of evidence-based prevention strategies to reduce ACL injury in female athletes. A list of six critical principles, which come from documented, large scale clinical trial studies and further analyses, were presented with ABC format including age, biomechanics, compliance, dosage, exercise, and feedback. Also, a grade for evidence and implications of future research is noted. Finally, in the conclusion section, importance of collaborative efforts from healthcare practitioners, researchers, and personnel associated with athletics is addressed.

High knee abduction moments are common risk factors for patellofemoral pain (PFP) and anterior cruciate ligament (ACL) injury in girls: is PFP itself a predictor for subsequent ACL injury?

BACKGROUND

Identifying risk factors for knee pain and anterior cruciate ligament (ACL) injury can be an important step in the injury prevention cycle.

OBJECTIVE

We evaluated two unique prospective cohorts with similar populations and methodologies to compare the incidence rates and risk factors associated with patellofemoral pain (PFP) and ACL injury.

METHODS

The 'PFP cohort' consisted of 240 middle and high school female athletes. They were evaluated by a physician and underwent anthropometric assessment, strength testing and three-dimensional landing biomechanical analyses prior to their basketball season. 145 of these athletes met inclusion for surveillance of incident (new) PFP by certified athletic trainers during their competitive season. The 'ACL cohort' included 205 high school female volleyball, soccer and basketball athletes who underwent the same anthropometric, strength and biomechanical assessment prior to their competitive season and were subsequently followed up for incidence of ACL injury. A one-way analysis of variance was used to evaluate potential group (incident PFP vs ACL injured) differences in anthropometrics, strength and landing biomechanics. Knee abduction moment (KAM) cut-scores that provided the maximal sensitivity and specificity for prediction of PFP or ACL injury risk were also compared between the cohorts.

RESULTS

KAM during landing above 15.4 Nm was associated with a 6.8% risk to develop PFP compared to a 2.9% risk if below the PFP risk threshold in our sample. Likewise, a KAM above 25.3 Nm was associated with a 6.8% risk for subsequent ACL injury compared to a 0.4% risk if below the established ACL risk threshold. The ACL-injured athletes initiated landing with a greater knee abduction angle and a reduced hamstrings-to-quadriceps strength ratio relative to the incident PFP group. Also, when comparing across cohorts, the athletes who suffered ACL injury also had lower hamstring/quadriceps ratio than the players in the PFP sample (p<0.05).

CONCLUSIONS

In adolescent girls aged 13.3 years, >15 Nm of knee abduction load during landing is associated with greater likelihood of developing PFP. Also, in girls aged 16.1 years who land with >25 Nm of knee abduction load during landing are at increased risk for both PFP and ACL injury.