Understanding of anterior cruciate ligaments, ACL injuries, surgical procedures, and rehabilitation has come a long way over the past 20 years, from open surgery followed by prolonged immobilization to arthroscopic procedures combined with accelerated rehabilitation. But when examining the consensus statement and research abstracts from April 2006 Proceedings of the ACL Research Retreat III: The Gender Bias in this issue of the JOSPT, the reader concludes that there is much yet to be understood about the injury mechanism and the prevention of ACL injuries.

J Orthop Sports Phys Ther. 2007;37(2):32. doi:10.2519/jospt.2007.0101

STUDY DESIGN: Case-control, descriptive pilot study. OBJECTIVE: To describe the differences in the performance of the craniocervical flexion test (CCFT) between individuals with chronic tension-type headache (CTTH) and healthy controls. To assess the relationship between the CCFT, forward head posture, and several clinical variables related to the intensity and temporal profile of headache. BACKGROUND: Musculoskeletal impairments of the craniocervical region might play an important role on the pathogenesis of CTTH. Deficits in the performance of the CCFT have been reported in patients with cervicogenic headache, nonspecific neck pain, and whiplash injury, but not in individuals with CTTH. MATERIAL AND METHODS: Ten patients with CTTH and 10 comparable controls without headache were studied. A headache diary was kept for 4 weeks to substantiate the diagnosis and to record the pain history. The CCFT was performed with the subject supine and required performing a gentle head-nodding action of craniocervical flexion. The activation pressure score (pressure that the subject can achieve and hold for 10 seconds), the performance pressure index (calculated by multiplying the activation pressure score by the number of successful repetitions), and the highest pressure score (the highest level that each subject was able to hold for 10 seconds from 20 to 30 mm Hg) were measured. Side-view pictures of each subject were taken in both sitting and standing positions to assess forward head posture (FHP) by measuring the craniovertebral angle. All measures were taken by an assessor blinded to the subject’s condition. RESULTS: Patients with CTTH had significantly lower values in both active pressure score and performance pressure index (P<.001), but not in the highest pressure score (P = .057), compared to controls. Patients with CTTH had a smaller craniovertebral angle (mean ± SD, 42.0° ± 6.6°), indicating a more FHP than controls (48.8° ± 2.5°), in the standing position (P<.01); but not in the sitting position (CTTH, 39° ± 8.9°; controls, 42.8° ± 8.9°, P = .10). No association between FHP and any of the CCFT variables was found (P>.05). Headache intensity and frequency did not seem to be related to the CCFT variables, but there was a positive association between headache duration and activation pressure score (r_s = 0.746, P = .02) and highest pressure score (r_s = 0.743, P = .02). CONCLUSIONS: These findings suggest possible impairments of the musculoskeletal system in individuals with CTTH, although it is not possible to determine if these impairments contributed to the etiology of CTTH or are as a result of the chronic headache condition.  

J Orthop Sports Phys Ther. 2007;37(2):33-39. doi:10.2519/ jospt.2007.2401

KEY WORDS: cervical spine, head, neck, pain

STUDY DESIGN: Prospective cohort. OBJECTIVE: To determine (1) the cumulative seasonal incidence and overall injury rate of medial tibial stress syndrome (MTSS) and (2) risk factors for MTSS with a primary focus on the relationship between navicular drop values and MTSS in high school cross-country runners. BACKGROUND: MTSS is a common injury among runners. However, few studies have reported the injury rate and risk factors for MTSS among adolescent runners. METHODS AND MEASURES: Data collected included measurement of bilateral navicular drop and foot length, and a baseline questionnaire regarding the runner’s height, body mass, previous running injury, running experience, and orthotic or tape use. Runners were followed during the season to determine athletic exposures (AEs) and occurrence of MTSS. RESULTS: The overall injury rate for MTSS was 2.8/1000 AEs. Although not statistically different, girls had a higher rate (4.3/1000 AEs) than boys (1.7/1000 AEs) (P = .11). Logistic regression modeling indicated that only gender and body mass index (BMI) were significantly associated with the occurrence of MTSS. However, when controlled for orthotic use, only BMI was associated with risk of MTSS. No significant associations were found between MTSS and navicular drop or foot length. CONCLUSIONS: Our findings suggest that navicular drop may not be an appropriate measure to identify runners who may develop MTSS during a cross-country season; thus, additional studies are needed to identify appropriate preseason screening tools.  

J Orthop Sports Phys Ther. 2007;37(2):40-47. doi:10.2519/jospt.2007.2343 

KEY WORDS: injury risk, female athlete, navicular drop, shin splints

STUDY DESIGN: Prospective single-group repeated-measures design. OBJECTIVES: To quantify electromyographic (EMG) signal amplitude of the gluteus maximus, gluteus medius, vastus medialis oblique, and biceps femoris during 5 unilateral weight-bearing exercises. BACKGROUND: Using normalized EMG (NEMG) signal amplitude as a measure of muscle activation and, therefore, an estimate of exercise intensity, the relative contributions and interac­tion of the hip and thigh muscles during unilateral weight-bearing exercise can be examined. With regard to potential efficiency for strengthening, data on the amount of EMG signal amplitude for these 4 muscles during commonly used exercises are limited. METHODS AND MEASURES: Twenty-three healthy, asymptomatic subjects (16 men, 7 women; mean ± SD age, 31.2 ± 5.8 years) participated. A repeated-measures analysis was conducted using general linear models. The percent maximum voluntary isometric contraction was measured within each subject across 4 muscles during 5 exercises for 2 sepa­rate trials. Effect sizes of pairwise comparisons were computed. RESULTS: Statistically significant differences were noted in the amount of mean NEMG signal amplitude for the 4 muscles across the 5 ex­ercises. A similar recruitment pattern between muscles was observed across all exercises. CONCLUSION: Even though all muscles except the biceps femoris demonstrated mean NEMG signal amplitudes sufficient for strength­ening, the wall squat produced the highest levels of activation and should be considered the most efficient for targeting any of the 4 muscles or for training a cooperative effort among the muscles. 

J Orthop Sports Phys Ther. 2007;37(2):48-55. doi:10.2519/jospt.2007.2354

KEY WORDS: gluteus maximus, gluteus me­dius, lower extremity, step-up, wall squat

STUDY DESIGN: Two-factor, mixed experimental design. OBJECTIVES: To compare movement patterns of subjects who are anterior cruciate ligament (ACL) deficient and classified as noncopers to controls during early stance of anticipated and unanticipated straight and cutting tasks. BACKGROUND: Altered neuromuscular control of subjects that are ACL deficient and noncoper theoretically influences movement patterns during unanticipated tasks. METHODS AND MEASURES: The study included 16 subjects who are ACL deficient, classified as noncopers, and 20 healthy controls. Data were collected using an Optotrak Motion Analysis System and force plate integrated with Motion Monitor Software to generate knee joint angles, moments, and power. Each testing session included anticipated tasks, straight walking task (ST), and 45° side-step cutting tasks (SSC), followed by a set of unexpected straight walking (STU) and unexpected sidestep cutting (SSCU) tasks in a random order. For all tasks speed was maintained at 2 m/s. Peak knee angle, moment, and power variables during early stance were compared using 2- way mixed-effects ANOVA models. RESULTS: For both the straight and sidestep tasks, the noncoper group did not show a dependence on whether the task was anticipated or unanticipated (group-by-condition interaction) for the knee angle (straight, P = .067; side-step cutting, P = .103), moment (straight, P = .079; side-step cutting, P = .996), and powers (straight, P = .181; side-step cutting, P = .183) during the loading response phase. However, during both straight and side-step cutting tasks, the subjects in the noncoper group used significantly lower knee flexion angles (straight, P = .002; side-step cutting, P = .019), knee moments (straight, P = .005; sidestep cutting, P<.001), and knee powers (straight, P = .013; side-step cutting, P<.001). CONCLUSIONS: This study suggests subjects that are ACL deficient and classified as noncopers use a common abnormal movement pattern of lower knee extensor loading even during unanticipated tasks.  

J Orthop Sports Phys Ther. 2007;37(2):56-64. doi:10.2519/jospt.2007.2292 

KEY WORDS: anterior cruciate ligament, cutting task, knee instability, neuromuscular control

J Orthop Sports Phys Ther. 2007;37(2):65-71. doi:10.2519/jospt.2007.2312

KEY WORDS: adverse reaction, arthralgia, myalgia, pharmacovigilance

The information acquired from self-reported outcome instruments is useful only if there is evidence to support the interpretation of obtained scores. To properly interpret scores, there should be evidence for content validity, construct validity, reliability, and responsive­ness. Evidence regarding score interpretation must also contain a description of the applica­ble test conditions, including information about the characteristics of subjects, timing of data collection, and construct of change. The objec­tive of this review was to identify self-reported outcome instruments that have evidence to support their usefulness for assessing the ef­fect of treatment directed at individuals with foot and ankle-related pathologic conditions in an orthopaedic physical therapy setting. In ad­dition, we provide specific information that will allow clinicians and researchers to select an appropriate instrument and properly interpret the obtained scores. Fourteen self-reported outcome instruments that met the objective of this review were identified. Five instruments, the Foot and Ankle Ability Measure, Foot Func­tion Index, Foot Health Status Questionnaire, Lower Extremity Function Scale, and Sports Ankle Rating System quality of life measure, satisfied all 4 categories of evidence (content validity, construct validity, reliability, and re­sponsiveness) outlined herein. 

J Orthop Sports Phys Ther. 2007;37(2):72-84. doi:10.2519/jospt.2007.2403

KEY WORDS: ankle, foot, outcome instru­ments, reliability, responsiveness, validity

There was a 50% increase in the number of abstract submissions this year. In the end, 33 abstracts were accepted. These were grouped into sessions addressing structural, neuromuscular, biomechanical, and hormonal factors that may influence the gender bias in ACL injury in­cidence. It was interesting to note that the majority of abstracts submitted were in the area of neuromuscular and biomechanical factors, with only a few in the ar­eas of structural and hormonal factors. This suggests a trend in the research focus towards the more modifiable factors.  

The retreat was cohosted by Kentucky Sports Medicine and Drayer Physical Therapy Institute and sponsored by DonJoy, Aircast, Bluegrass Bracing, and Smith and Nephew. To accommodate the increase in number of high-quality abstracts, the meeting was ex­tended to 2 full days. The retreat was attended by both clinicians and scientists with a common interest in the ACL injury gender bias. The 60-plus participants in­cluded registrants from across the United States as well as Canada and Australia. As with the previous retreats, the group consisted of physicians, physical therapists, athletic trainers, and scientists in the areas of biome­chanics, motor control, and neuromuscular function. Thirty percent of the participants in the 2006 retreat were participants in a previous retreat as well. 

The for­mat of the meeting included 1 keynote presentation per day, along with 15-minute podium presentations made by some of the participants. The keynote presenters were chosen for their scientific contribution to the un­derstanding of factors associated with the gender bias seen in the incidence of ACL injuries. Ton van den Bo­gert, PhD, from the Department of Biomedical Engi­neering at the Cleveland Clinic gave the first keynote titled "ACL Injuries: Do We Know the Mechanisms?" The second keynote presenter was William Garrett, MD, PhD, from the Department of Orthopedics at Duke University, whose talk was titled "Anterior Cruciate Lig­ament Injury Mechanisms and Risk Factors." Following all of the presentations, a consensus development ses­sion was held. In the pages of this supplement, you will find the consensus statement and an abstract on each of the 33 presentations made at the conference, organized by the topics listed above. 

J Orthop Sports Phys Ther. 2007;37(2):A1-A32. doi:10.2519/jospt.2007.0301

KEY WORDS: anterior cruciate ligament, ACL injuries, gender