Can we spread the risk? A demand-share perspective to sustained hamstring health. Practical examples.

This short practical paper gives examples of exercises of synergists that assist the biceps femoris long head, the most commonly injured hamstring muscle in repeated sprint field sports (soccer, rugby) with the aim of reducing risk of or recurrence of injury. It is a companion to the theoretical piece of the same name.

The validity of the nordic hamstring lower for a field-based assessment of eccentric hamstring strength.

CONTEXT: Hamstring injury-risk assessment has primarily been investigated using isokinetic dynamometry. However, practical issues such as cost and availability limit the widespread application of isokinetics for injury-risk assessment; thus, field-based alternatives for assessing eccentric hamstring strength are needed. OBJECTIVE: The aim of this study was to investigate the validity of the angle achieved during Nordic hamstring lowers (break-point angle) as a field-based test for eccentric hamstring strength. DESIGN: Exploratory study. SETTING: Laboratory. PARTICIPANTS: Sixteen male (n = 7) and female (n = 9) soccer players (mean ± SD age 24 ± 6 y, height 1.77 ± 0.12 m, and body mass 68.5 ± 16.5 kg) acted as subjects for the study. MAIN OUTCOME MEASURES: The authors explored relationships between the Nordic break-point angle (the point at which the subject can no longer resist the increasing gravitational moment during a Nordic hamstring lower) measured from video and isokinetic peak torque and angle of peak torque of right- and left-knee flexors. RESULTS: The results revealed a meaningful relationship between eccentric knee-flexor peak torque (average of right and left limbs) and the Nordic break-point angle (r = -.808, r2 = 65%, P < .00001). However, there was a weak relationship observed (r = .480, r2 = 23%, P = .06) between break-point angle and the angle of peak torque (average of right and left limbs). CONCLUSIONS: The results suggest that the break-point angle achieved during Nordic hamstring lowers could be used as a field-based assessment of eccentric hamstring strength.

Diagnostic accuracy of clinical tests for assessment of hamstring injury: a systematic review.

STUDY DESIGN: Systematic literature review. BACKGROUND: The diagnosis of a hamstring injury has traditionally relied on various clinical measures (eg, palpation, swelling, manual resistance), as well as the use of diagnostic imaging. But a few studies have suggested the use of specific clinical tests that may be helpful for the diagnostic process. OBJECTIVE: To summarize the current literature on the diagnostic accuracy of orthopaedic special tests for hamstring injuries and to determine their clinical utility. METHODS: A computer-assisted literature search of the MEDLINE, CINAHL, and Embase databases (along with a manual search of grey literature) was conducted using key words related to diagnostic accuracy of hamstring injuries. To be considered for inclusion in the review, the study required (1) patients with hamstring or posterior thigh pain; (2) a cohort, case-control, or cross-sectional design; (3) inclusion of at least 1 clinical examination test used to evaluate hamstring pathology; (4) comparison against an acceptable reference standard; (5) reporting of diagnostic accuracy of the measures (sensitivity [SN], specificity [SP], or likelihood ratios); and (6) publication in English. SN, SP, and positive and negative likelihood ratios were calculated for each diagnostic test. RESULTS: The search strategy identified 602 potential articles, of which only 3 articles met the inclusion criteria, with only 1 of these 3 articles being of high quality. Two of the studies investigated a single special test, whereas the third article examined a composite clinical assessment employing various special tests. The SN values ranged from 0.55 (95% confidence interval [CI]: 0.46, 0.69) for the active range-of-motion test to 1.00 (95% CI: 0.97, 1.00) for the taking-off-the-shoe test. The SP values ranged from 0.03 (95% CI: 0.00, 0.22) for the composite clinical assessment to 1.00 (95% CI: 0.97, 1.00) for the taking-off-the-shoe test, active range-of-motion test, passive range-of-motion test, and resisted range-of-motion test. The use of a single special test demonstrated stronger SP than SN properties, whereas the composite clinical assessment demonstrated stronger SN than SP properties. CONCLUSION: Very few studies have investigated the utilization of clinical special tests for the diagnosis of hamstring injuries. Further studies of higher quality design are suggested prior to advocating independent clinical utilization of these special tests. LEVEL OF EVIDENCE: Diagnosis, level 3b.

Incremental role of three-dimensional over two-dimensional ultrasound in the assessment of traumatic peripheral arteriovenous fistula.

We present a patient with an accidental self-inflicted stab wound to his right thigh in whom three-dimensional (3D) ultrasound was able to find two communications between the right femoral artery and the femoral vein, in contrast to two-dimensional (2D) peripheral ultrasound which could find only one communication between them, thereby showing an incremental value of 3D over 2D ultrasound.

The need for lumbar-pelvic assessment in the resolution of chronic hamstring strain.

A lumbar-pelvic assessment and treatment model based on a review of clinical and anatomical research is presented for consideration in the treatment of chronic hamstring strain. The origin of the biceps femoris muscle attaches to the pelvis at the ischial tuberosity and to the sacrum via the sacrotuberous ligament. The biomechanics of the sacroiliac joint and hip, along with lumbar-pelvic stability, therefore play a significant role in hamstring function. Pelvic asymmetry and/or excessive anterior tilt can lead to increased tension at the biceps origin and increase functional demands on the hamstring group by inhibiting its synergists. Joint proprioceptive mechanisms may play a significant role in re-establishing balance between agonists and antagonists. An appreciation of neuromuscular connections as well as overall lumbar-pelvic structural assessment is recommended in conjunction with lumbar-pelvic strengthening exercises to help resolve chronic hamstring strain.

Hamstring injuries: risk assessment and injury prevention.

INTRODUCTION: Hamstring injuries are one of the most common injuries associated with sports participation. The aim of this review is to outline identified risk factors and examine preventative strategies for reducing the occurrence of this form of injury. METHODS: An electronic search of Medline and SCOPUS was carried out for key words related to the area. RESULTS: A number of risk factors, including both intrinsic and modifiable, were identified. Important aspects of an exercise programme were then outlined based on these risk factors. CONCLUSION: A programme specifically designed to reduce the risk of hamstring injury by taking a strategised approach to exercise prescription may reduce the risk of hamstring injury. However, further research is required to determine the optimal programme for reducing the risk of injury.

Assessment of physical examination and magnetic resonance imaging findings of hamstring injury as predictors for recurrent injury.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To examine clinical and magnetic resonance imaging (MRI) features of hamstring muscle injury to determine if any are predictive for recurrent injury. BACKGROUND: Hamstring muscle strain injury and subsequent recurrent injury are common. Little information exists on factors that may increase the risk for recurrent injury. METHODS AND MEASURES: The subjects were athletes from 3 professional Australian Rules football teams (n = 162). Anthropometric measurements, clinical signs, convalescent interval, and MRI assessment and measurement were undertaken and recorded in athletes with hamstring muscle strain injury. Athletes were followed for the presence, or absence, of recurrent injury to the same-side posterior thigh over the same and subsequent playing seasons. RESULTS: Thirty athletes met criteria for hamstring injury. Twelve (40%) of 30 athletes had recurrent injury within the same season, with an additional 7 athletes having recurrent injury in the subsequent season. None of the features examined were associated with increased recurrent injury risk within the same playing season. Statistical analysis demonstrated that when combining the same with the subsequent playing season a larger size of initial hamstring injury, as measured by MRI, was associated with an increased risk for recurrent injury (P<.01). A measured transverse size of injury greater than 55% of the muscle, or calculated volume of injury greater than 21.8 cm3, resulted in an increased risk for hamstring recurrence of 2.2 (95% CI, 0.88-5.32) and 2.3 (95% CI, 0.94-5.81) times, respectively, when compared to athletes with hamstring injuries below these measurements. CONCLUSIONS: A larger size of hamstring injury was indicative of higher risk for recurrent injury but only after the subsequent playing season was considered along with the same playing season. None of the other parameters tested, including a shorter convalescent interval and clinical features, were associated with an increased risk for recurrent injury. However, due to low sample size the certainty of these conclusions may be limited.

Assessment of player performance following return to sport after hamstring muscle strain injury.

OBJECTIVE: To determine if there is any decrease in playing performance of athletes following return to sport after recovery from hamstring muscle strain injury. DESIGN: Prospective cohort study. PARTICIPANTS: One professional Australian football team over two playing seasons. METHODS: For every game, the team coach rated player performance proportional to time spent on the ground playing (an integer score out of a maximum of 10). Player performance ratings were compared pre- and post-hamstring muscle strain injury to assess player performance upon return to sport. RESULTS: Thirteen athletes had hamstring injuries and the required player ratings were available. The mean player performance rating for the entire playing season in which the player was injured was 6.9. The mean player performance rating for the two games prior to injury was 6.8 as opposed to 5.4 for the two games after return to sport. Athletes had a significantly lower player performance rating immediately upon return to sport when compared to ratings for the entire season (p<0.001) and when compared to ratings from the two games prior to injury (p<0.001). CONCLUSIONS: Following return to sport from hamstring injury, player performance as assessed by the team coach is reduced. This suggests that some athletes may return to sport prior to complete resolution of the injury.

A comparison between clinical assessment and magnetic resonance imaging of acute hamstring injuries.

BACKGROUND: Physicians evaluating hamstring strains in professional football players are increasingly turning to magnetic resonance imaging to support the clinical diagnosis and management of the injury. However, little information is available to assess how magnetic resonance imaging compares with the clinical evaluation in establishing the duration of rehabilitation required. HYPOTHESIS: Magnetic resonance imaging of hamstring strains can be useful in determining duration of rehabilitation. STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 1. METHODS: Fifty-eight professional football players with a diagnosis of hamstring injury made by the team physician were enrolled in the study. All players underwent magnetic resonance imaging and a clinical evaluation by an independent physical therapist within 3 days of the injury. Presence, type, and location of injury were recorded in each examination. The physical therapist estimated the time required until return to competition, and the radiologist used the length of the injury (coronal view) to establish rehabilitation duration. Both clinicians were blinded to the other modality. RESULTS: Clinical and magnetic resonance imaging assessments were in agreement in 38 of 58 cases (65.5%). In 18 cases (31.0%), a clinically positive diagnosis was made, but no abnormalities were evident on magnetic resonance imaging. In 2 cases (3.4%), magnetic resonance imaging detected an injury, whereas the clinical examination had negative or equivocal findings. Both clinical examination and magnetic resonance imaging findings were strongly correlated with the actual time required to return to competition (r = .69, P < .001 and r = .58, P < .001, respectively). The correlation coefficient between clinical predictions and magnetic resonance imaging findings was moderate (r = .36, P = .006). CONCLUSION: This study shows that magnetic resonance imaging is not required for estimating the duration of rehabilitation of an acute minor or moderate hamstring injury in professional football players.

MR imaging in the presence of small circular metallic implants. Assessment of thermal injuries.

PURPOSE: The thermal effects of MR imaging in the presence of circular nonferro-magnetic metallic implants were studied in 6 rabbits. MATERIAL AND METHODS: A sternotomy was performed and fixed with stainless steel wires, and small titanium rings (diameter 3 mm) were placed on the surface of the ascending aorta and subcutaneous tissue of the thigh. Four of the rabbits were exposed to an imaging procedure with a 1.5 T scanner applying a T1-weighted spin-echo sequence and a gradient echo sequence. Two of the animals served as unexposed controls. Thirty-six hours after the exposure, tissues adjacent to the implants were examined histologically and compared with corresponding samples of the control animals. RESULTS: In the area of the titanium rings, histologic analysis revealed slight inflammatory changes apparently caused by the operation. No evidence of thermal injury was found, suggesting that the presence of the rings does not contraindicate MR examinations. Necrosis was noted in all of the sternal specimens. This was probably post-operative, but it impaired the assessment of thermal injury in this area.