Early versus delayed lengthening exercises for acute hamstring injury in male athletes: a randomised controlled clinical trial.

BACKGROUND: To evaluate the efficacy of early versus delayed introduction of lengthening (ie, eccentric strengthening) exercises in addition to an established rehabilitation programme on return to sport duration for acute hamstring injuries in a randomised controlled superiority trial. METHODS: 90 male participants (age: 18-36 years, median 26 years) with an MRI-confirmed acute hamstring injury were randomised into an early lengthening (at day 1 of rehabilitation) group or a delayed lengthening (after being able to run at 70% of maximal speed) group. Both groups received an established rehabilitation programme. The primary outcome was time to return to sport (ie, time from injury to full unrestricted training and/or match play). The secondary outcome was reinjury rate within 12 months after return to sport. Other outcomes at return to sport included the Askling H-test, hamstring strength, clinical examination and readiness questions. RESULTS: The return to sport in the early lengthening group was 23 (IQR 16-35) days and 33 (IQR 23-40) days in the delayed lengthening group. For return to sport (in days), the adjusted HR for the early lengthening group compared with the delayed lengthening group was 0.95 (95% CI 0.56 to 1.60, p=0.84). There was no significant difference between groups for reinjury rates within 2 months (OR=0.94, 95% CI 0.18 to 5.0, p=0.94), from 2 to 6 months (OR=2.00, 95% CI 0.17 to 23.3, p=0.58), and 6 to 12 months (OR=0.57, 95% CI 0.05 to 6.6, p=0.66). CONCLUSION: Accelerating the introduction of lengthening exercises in the rehabilitation of hamstring injury in male athletes did not improve the time to return to sport nor the risk of reinjury.

Similar Isokinetic Strength Preinjury and at Return to Sport after Hamstring Injury.

INTRODUCTION: Side-to-side strength differences are often used in return to sport (RTS) decision making after hamstring injury. In football (soccer), there is little consensus, and a side-to-side difference of <10% is often suggested as a criterion. To date, no study has determined whether differences exist when comparing the strength of the injured limb at RTS with the preinjury level. PURPOSE: The aims of this study were to compare the isokinetic strength at RTS with preinjury strength in the injured limb and to investigate the side-to-side differences at RTS. METHODS: This study was based on a pooled group of patients participating in two single-site randomized controlled trials. All eligible professional male soccer players who suffered a hamstring injury confirmed by magnetic resonance imaging were included. The isokinetic strength of the injured limb at RTS was compared with preinjury screening tests, and the side-to-side difference was determined at both time points. RESULTS: In total, 41 hamstring injuries were included in the analyses. Side-to-side differences in isokinetic strength at RTS were similar to preinjury levels. At RTS, the average strength of the injured limb was >95% compared with preinjury strength. Overall, 63.4% of the players had a >10% negative strength difference (i.e., the injured limb being weaker), and 57.9% of the players had a >10% positive strength difference (i.e., the injured limb being stronger) in at least one of the five isokinetic variables. CONCLUSION: The distribution of isokinetic strength differences when comparing strength at RTS with preinjury measures was similar, urging clinical caution when interpreting these results. Small changes in the isokinetic strength of the injured limb at RTS compared with preinjury strength suggest that isokinetic cutoff values are not useful to guide the restoration of strength as a criterion for RTS after hamstring injury.

New MRI muscle classification systems and associations with return to sport after acute hamstring injuries: a prospective study.

OBJECTIVES: To determine agreement between modified Peetrons, Chan acute muscle strain injury classification and British Athletics Muscle Injury Classification (BAMIC) and to investigate their associations and ability to predict time to return to sport (RTS). METHODS: Male athletes (n=176) with acute hamstring injury and MRI (1.5T) ≤5 days were followed until RTS. MRIs were scored using standardised forms. RESULTS: For MRI-positive injuries there was moderate agreement in severity grading (κ = 0.50-0.56). Substantial variance in RTS was demonstrated within and between MRI categories. Mean differences showed an overall main effect for severity grading (p < 0.001), but post hoc pairwise comparisons for BAMIC (grade 0a/b vs. 1, p = 0.312; 1 vs 2, p = 0.054; 0a/b vs 2, p < 0.001; 1 vs 3, p < 0.001) and mean differences for anatomical sites (BAMIC a-c, p < 0.001 [a vs b, p = 0.974; a vs c, p = 0.065; b vs c, p = 0.007]; Chan anatomical sites 1-5, p < 0.077; 2A-C, p = 0.373; 2a-e, p = 0.008; combined BAMIC, p < 0.001) varied. For MRI-positive injuries, total explained RTS variance was 7.6-11.9% for severity grading and BAMIC anatomical sites. CONCLUSIONS: There was wide overlap between/variation within the grading/classification categories. Therefore, none of the classification systems could be used to predict RTS in our sample of MRI-positive hamstring injuries. KEY POINTS: • Days to RTS varied greatly within the grading and classification categories. • Days to RTS varied greatly between the grading and classification categories. • Using MRI classification systems alone to predict RTS cannot be recommended. • The specific MRI classification used should be reported to avoid miscommunication.

Cohen's MRI scoring system has limited value in predicting return to play.

PURPOSE: Numerous authors have hypothesised that MRI scoring systems provide a valid means of predicting return to play duration following an acute hamstring muscle strain. The purpose is to prospectively investigate the predictive value of the MRI scoring system of Cohen for return to sport (RTS), following an acute hamstring injury. METHODS: Male football (soccer) players (n = 139) with acute onset posterior thigh pain underwent standardised clinical and MRI examinations within 5 days after injury. All players underwent a standardised physiotherapy regimen with RTS documented. The MRI scoring was statistically evaluated against RTS. RESULTS: One hundred and ten MRI-positive hamstring injuries were evaluated with RTS duration ranging from 1 to 66 days. Total Cohen's MRI score accounted for approximately 4% of the variance in RTS duration. When comparing those with an MRI score of 10 or more took on average 9.8 days longer to RTS than those with an MRI score less than 10 (effect size: 0.85, p < 0.01). CONCLUSIONS: Utilising the Cohen's MRI scoring system previously described, we were unable to provide a clinically useful prognosis for RTS in male soccer players. This may reflect the broader challenges of attempting to accurately determine RTS duration from imaging performed at a single point in time. LEVEL OF EVIDENCE: Prospective case series, IV.

Clinical implications from daily physiotherapy examination of 131 acute hamstring injuries and their association with running speed and rehabilitation progression.

AIM: To investigate the association of daily clinical measures and the progression of rehabilitation and perceived running effort. METHODS: A cohort of 131 athletes with an MRI-confirmed acute hamstring injury underwent a standardised criteria-based rehabilitation protocol. Descriptive and inferential statistics were used to investigate the association between daily clinical subjective and objective measures and both the progression of rehabilitation and perceived running effort. These measures included different strength, palpation, flexibility and functional tests. Inter-rater and intrarater reliability and minimal detectable change were established for the clinical measures of strength and flexibility by examining measures taken on consecutive days for the uninjured leg. RESULTS: The progression of the daily measures was seen to be non-linear and varied according to the measure. Intra-rater reliability for the strength and flexibility measures were excellent (95% CI ≥0.85 for all measures). Strength (in the outer range position) and flexibility (in maximum hip flexion with active knee extension (MHFAKE) in supine) were best associated with rehabilitation progression and perceived running effort. Additionally, length of pain on palpation was usefully associated with rehabilitation progression. At lower perceived running effort there was a large variation in actual running speed. CONCLUSION: Daily physical measures of palpation pain, outer range strength, MHFAKE and reported pain during daily activity are useful to inform the progression of rehabilitation. TRIAL REGISTRATION NUMBER: NCT01812564 and NCT02104258.

Intra- and interrater reliability of three different MRI grading and classification systems after acute hamstring injuries.

OBJECTIVE: To assess and compare the intra- and interrater reliability of three different MRI grading and classification systems after acute hamstring injury. METHODS: Male athletes (n=40) with clinical diagnosis of acute hamstring injury and MRI ≤5days were selected from a prospective cohort. Two radiologists independently evaluated the MRIs using standardised scoring form including the modified Peetrons grading system, the Chan acute muscle strain injury classification and the British Athletics Muscle Injury Classification. Intra-and interrater reliability was assessed with linear weighted kappa (κ) or unweighted Cohen's κ and percentage agreement was calculated. RESULTS: We observed 'substantial' to 'almost perfect' intra- (κ range 0.65-1.00) and interrater reliability (κ range 0.77-1.00) with percentage agreement 83-100% and 88-100%, respectively, for severity gradings, overall anatomical sites and overall classifications for the three MRI systems. We observed substantial variability (κ range -0.05 to 1.00) for subcategories within the Chan classification and the British Athletics Muscle Injury Classification, however, the prevalence of positive scorings was low for some subcategories. CONCLUSIONS: The modified Peetrons grading system, overall Chan classification and overall British Athletics Muscle Injury Classification demonstrated 'substantial' to 'almost perfect' intra- and interrater reliability when scored by experienced radiologists. The intra- and interrater reliability for the anatomical subcategories within the classifications remains unclear.

Can Clinical Evaluation Predict Return to Sport after Acute Hamstring Injuries? A Systematic Review.

BACKGROUND: The current literature on the value of clinical evaluation for predicting time to return to sport (RTS) after acute hamstring injuries has not been systematically summarised. OBJECTIVES: The aim of this study was to systematically review the literature on the prognostic value of clinical findings (patient history and physical examination) for time to RTS after acute hamstring injuries in athletes. DATA SOURCES: The databases PubMed, EMBASE, SPORTDiscus and Cochrane Library were searched between October 2014 and August 2015. STUDY ELIGIBILITY CRITERIA: Studies evaluating patient history and/or physical assessment findings as possible predictors for time to RTS (described in days or weeks) following acute hamstring injuries in athletes were eligible for inclusion. DATA ANALYSIS: Two authors independently screened the search results and assessed risk of bias using the modified Quality in Prognosis Studies (QUIPS) tool for quality appraisal of prognosis studies. We used a best-evidence synthesis to determine the level of evidence. RESULTS: Sixteen studies were included, of which one study had a low risk of bias and 15 had a high risk of bias. Moderate evidence for an association with time to RTS was found for three clinical findings (visual analogue scale; pain at time of injury, self-predicted time to RTS and clinician predicted time to RTS). There was limited evidence for an association with time to RTS for seven clinical findings (muscle pain during everyday activities, popping sound at injury, forced to stop within 5 min, visual bruising at the site of injury, width (cm) of tenderness to palpation, pain on trunk flexion and pain on active knee flexion initially after injury). The remaining clinical findings revealed either conflicting evidence or limited evidence for an association with time to RTS. CONCLUSION: There is at present no strong evidence that any clinical finding at baseline provides a valuable prognosis for time to RTS after an acute hamstring injury. There is moderate evidence that visual analogue scale pain at time of injury and predictions for time to RTS by the patient and the clinician are associated with time to RTS. The methodological quality of the current literature is characterised by a substantial risk of bias and reporting of RTS definitions and criteria for RTS were inconsistent. We provide recommendations that can guide the design of future studies.

Measuring heterogeneity of reinjury risk assessments at the time of clearance to return to play: A feasibility study.

OBJECTIVES: Different individuals may make different return to play (RTP) decisions due to different risk assessments or risk tolerances. Our objectives were to determine the feasibility of eliciting reinjury risk assessments with Bayesian methods, and risk tolerance with questionnaires, from clinicians and athletes in a real-world RTP setting. DESIGN: Feasibility study with a descriptive prospective case-series. METHODS: We recruited the athlete, sport physician and physiotherapist caring for an athlete ("triplet") within on-going groin and hamstring injury studies. We applied Bayesian methods to elicit estimates for reinjury risk over the next 2 months, based on the available clinical knowledge, and projected activity level. We used a standardized questionnaire to elicit factors affecting risk tolerance. RESULTS: Although our methods appeared feasible in general, there were important challenges that included language, time availability of practicing clinicians, and general work-flow issues related to embedding our study within an on-going larger study. We did obtain valuable data from more than one person on 10 of the 15 eligible athletes recruited. Despite the limited number of cases, there were clinically meaningful differences in risk estimates in some cases. In one triplet, participants estimated the reinjury risk between 1-10%, 20-50% and 30-40% for the same athlete. The most common factors modifying risk tolerance were "timing and season", "pressure from athlete", and "external pressure". CONCLUSIONS: Bayesian methods for risk elicitation in clinical sport medicine are feasible, and large differences in both risk estimation and risk tolerance sometimes occur.

MRI appearance does not change in the first 7 days after acute hamstring injury-a prospective study.

BACKGROUND: The optimal timing of MRI following acute hamstring injury is not known and is mainly based on expert opinions. AIMS: To describe the day-to-day changes in the extent of oedema and investigate the optimal timing for detection of fibre disruption on MRI following acute hamstring injuries. STUDY DESIGN: Prospective, descriptive study. METHODS: We performed standardised MRI (1.5T) ≤1 day after injury in male athletes with acute hamstring injury. If initial MRI revealed positive signs of injury (increased signal intensity on fluid sensitive sequences), consecutive MRIs were obtained daily throughout the subsequent week (ie, 7 times). The MRI parameters (day 1-7) were scored by a single radiologist using a standardised scoring form. The day-to-day changes in the extent of oedema (distance from tuber, craniocaudal length, mediolateral width and anteroposterior depth) and the presence and extent of fibre disruption (tear) were assessed with descriptive statistics and repeated measures using analysis of variance of log-transformed data. The overall main effect for time was reported with a significance level set at p<0.05. RESULTS: 13 out of 132 male athletes assessed for eligibility between January 2014 and December 2015 were included. 1 dropped out, while 12 (31 years, range 20-49) completed the study; 11 had 7 MRI scans each and one had 5 MRI scans performed. There were no significant day-to-day changes for any of the extent of oedema measures (p values ranging from 0.12 to 0.81). Fibre disruption (tear), present in 5 of the athletes, was detectable from day 1, with small and insignificant day-to-day changes (p values ranging from 0.45 to 0.95). CONCLUSIONS: We observed insignificant day-to-day changes in the extent of oedema throughout the first week following acute hamstring injury. Fibre disruption (tear) was detectable from the first day after injury. These findings indicate that MRI can be performed on any day during the first week following an acute (hamstring) muscle injury.

Hamstring Reinjuries Occur at the Same Location and Early After Return to Sport: A Descriptive Study of MRI-Confirmed Reinjuries.

BACKGROUND: Despite relatively high reinjury rates after acute hamstring injuries, there is a lack of detailed knowledge about where and when hamstring reinjuries occur, and studies including imaging-confirmed reinjuries are scarce. PURPOSE: To investigate the location, radiological severity, and timing of reinjuries on magnetic resonance imaging (MRI) compared with the index injury. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A MRI scan was obtained ≤5 days after an acute hamstring index injury in 180 athletes, and time to return to sport (RTS) was registered. Athletes with an MRI-confirmed reinjury in the same leg ≤365 days after RTS were included. Categorical grading and standardized MRI parameters of the index injury and reinjury were scored by a single radiologist (with excellent intraobserver reliability). To determine the location of the reinjury, axial and coronal views of the index injury and reinjury were directly compared on proton density-weighted fat-suppressed images. RESULTS: In the 19 athletes included with reinjury, 79% of these reinjuries occurred in the same location within the muscle as the index injury. The median time to RTS after the index injury was 19 days (range, 5-37 days; interquartile range [IQR], 15 days). The median time between the index injury and reinjury was 60 days (range, 20-316 days; IQR, 131 days) and the median time between RTS after the index injury and the reinjury was 24 days (range, 4-311 days; IQR, 140 days). More than 50% of reinjuries occurred within 25 days (4 weeks) after RTS from the index injury and 50% occurred within 50 days after the index injury. All reinjuries with more severe radiological grading occurred in the same location as the index injury. CONCLUSION: The majority of the hamstring reinjuries occurred in the same location as the index injury, early after RTS and with a radiologically greater extent, suggesting incomplete biological and/or functional healing of the index injury. Specific exercise programs focusing on reinjury prevention initiated after RTS from the index injury are highly recommended.

2016 Consensus statement on return to sport from the First World Congress in Sports Physical Therapy, Bern.

Deciding when to return to sport after injury is complex and multifactorial-an exercise in risk management. Return to sport decisions are made every day by clinicians, athletes and coaches, ideally in a collaborative way. The purpose of this consensus statement was to present and synthesise current evidence to make recommendations for return to sport decision-making, clinical practice and future research directions related to returning athletes to sport. A half day meeting was held in Bern, Switzerland, after the First World Congress in Sports Physical Therapy. 17 expert clinicians participated. 4 main sections were initially agreed upon, then participants elected to join 1 of the 4 groups-each group focused on 1 section of the consensus statement. Participants in each group discussed and summarised the key issues for their section before the 17-member group met again for discussion to reach consensus on the content of the 4 sections. Return to sport is not a decision taken in isolation at the end of the recovery and rehabilitation process. Instead, return to sport should be viewed as a continuum, paralleled with recovery and rehabilitation. Biopsychosocial models may help the clinician make sense of individual factors that may influence the athlete's return to sport, and the Strategic Assessment of Risk and Risk Tolerance framework may help decision-makers synthesise information to make an optimal return to sport decision. Research evidence to support return to sport decisions in clinical practice is scarce. Future research should focus on a standardised approach to defining, measuring and reporting return to sport outcomes, and identifying valuable prognostic factors for returning to sport.

Injury and illness surveillance during the 24th Men's Handball World Championship 2015 in Qatar.

BACKGROUND: The IOC encourages international federations to establish systematic athlete injury and illness surveillance programmes. OBJECTIVE: To describe pattern of injuries and illnesses during the 24th Men's Handball World Championship 2015 by implementing the IOC injury and illness surveillance protocol. METHODS: The medical staff of participating teams (n=24) were requested to report all new injuries and illnesses during matches and/or training on a daily basis throughout the event (15 January to 1 February, 2015). Exposure (number of player-hours) during all matches was calculated for all players (n=384) and for each of the 4 player positions (wing, back, line and goalkeeper). RESULTS: Medical staff of all teams submitted 96.7% (n=325) of the daily report forms. In total, 27.1% of the players were injured, and of the 132 injuries reported, 40% were time-loss injuries. The total incidence of injuries was 104.5 per 1000 player-hours. The highest risk of injury was found among line players, and more injuries occurred during the first half of the matches. The most frequent injury location was the ankle, followed by the thigh, knee and head/face. The majority of injuries were contusion, sprain or strain. In total, 10.9% of the players were affected by an illness during the event. Of the 42 cases recorded, 31 (73.8%) were reported as respiratory tract infection. CONCLUSIONS: The risk of injury in handball is high among Olympic sports. Preventive measures should focus on contusions, ankle sprains, and thigh muscle strains, as well as measures aimed to reduce upper respiratory tract infections.

MRI does not add value over and above patient history and clinical examination in predicting time to return to sport after acute hamstring injuries: a prospective cohort of 180 male athletes.

BACKGROUND: MRI is frequently used in addition to clinical evaluation for predicting time to return to sport (RTS) after acute hamstring injury. However, the additional value of MRI to patient history taking and clinical examination remains unknown and is debated. AIM: To prospectively investigate the predictive value of patient history and clinical examination at baseline alone and the additional predictive value of MRI findings for time to RTS using multivariate analysis while controlling for treatment confounders. METHODS: Male athletes (N=180) with acute onset posterior thigh pain underwent standardised patient history, clinical and MRI examinations within 5 days, and time to RTS was registered. A general linear model was constructed to assess the associations between RTS and the potential baseline predictors. A manual backward stepwise technique was used to keep treatment variables fixed. RESULTS: In the first multiple regression model including only patient history and clinical examination, maximum pain score (visual analogue scale, VAS), forced to stop within 5 min, length of hamstring tenderness and painful resisted knee flexion (90°), showed independent associations with RTS and the final model explained 29% of the total variance in time to RTS. By adding MRI variables in the second multiple regression model, maximum pain score (VAS), forced to stop within 5 min, length of hamstring tenderness and overall radiological grading, showed independent associations and the adjusted R(2) increased from 0.290 to 0.318. Thus, additional MRI explained 2.8% of the variance in RTS. SUMMARY: There was a wide variation in time to RTS and the additional predictive value of MRI was negligible compared with baseline patient history taking and clinical examinations alone. Thus, clinicians cannot provide an accurate time to RTS just after an acute hamstring injury. This study provides no rationale for routine MRI after acute hamstring injury. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Identifier: NCT01812564.