Rehabilitation for hamstring injuries

Effectiveness of Conservative Interventions After Acute Hamstrings Injuries in Athletes: A Living Systematic Review

BACKGROUND

Hamstrings injuries are common in sports and the reinjury risk is high. Despite the extensive literature on hamstrings injuries, the effectiveness of the different conservative (i.e., non-surgical) interventions (i.e., modalities and doses) for the rehabilitation of athletes with acute hamstrings injuries is unclear.

OBJECTIVE

We aimed to compare the effects of different conservative interventions in time to return to sport (TRTS) and/or time to return to full training (TRFT) and reinjury-related outcomes after acute hamstrings injuries in athletes.

DATA SOURCES

We searched CINAHL, Cochrane Library, EMBASE, PubMed, Scopus, SPORTDiscus, and Web of Science databases up to 1 January, 2022, complemented with manual searches, prospective citation tracking, and consultation of external experts.

ELIGIBILITY CRITERIA

The eligibility criteria were multi-arm studies (randomized and non-randomized) that compared conservative treatments of acute hamstrings injuries in athletes.

DATA ANALYSIS

We summarized the characteristics of included studies and conservative interventions and analyzed data for main outcomes (TRTS, TRFT, and rate of reinjuries). The risk of bias was judged using the Cochrane tools. Quality and completeness of reporting of therapeutic exercise programs were appraised with the i-CONTENT tool and the certainty of evidence was judged using the GRADE framework. TRTS and TRFT were analyzed using mean differences and the risk of reinjury with relative risks.

RESULTS

Fourteen studies (12 randomized and two non-randomized) comprising 730 athletes (mostly men with ages between 14 and 49 years) from different sports were included. Nine randomized studies were judged at high risk and three at low risk of bias, and the two non-randomized studies were judged at critical risk of bias. Seven randomized studies compared exercise-based interventions (e.g., L-protocol vs C-protocol), one randomized study compared the use of low-level laser therapy, and three randomized and two non-randomized studies compared injections of platelet-rich plasma to placebo or no injection. These low-level laser therapy and platelet-rich plasma studies complemented their interventions with an exercise program. Only three studies were judged at low overall risk of ineffectiveness (i-CONTENT). No single intervention or combination of interventions proved superior in achieving a faster TRTS/TRFT or reducing the risk of reinjury. Only eccentric lengthening exercises showed limited evidence in allowing a shorter TRFT. The platelet-rich plasma treatment did not consistently reduce the TRFT or have any effect on the risk of new hamstrings injuries. The certainty of evidence was very low for all outcomes and comparisons.

CONCLUSIONS

Available evidence precludes the prioritization of a particular exercise-based intervention for athletes with acute hamstrings injuries, as different exercise-based interventions showed comparable effects on TRTS/TRFT and the risk of reinjuries. Available evidence also does not support the use of platelet-rich plasma or low-level laser therapy in clinical practice. The currently available literature is limited because of the risk of bias, risk of ineffectiveness of exercise protocols (as assessed with the i-CONTENT), and the lack of comparability across existing studies.

CLINICAL TRIAL REGISTRATION

PROSPERO CRD42021268499 and OSF ( https://osf.io/3k4u2/ ).

The mechanism of hamstring injuries - a systematic review

Background

Injuries to the hamstring muscles are among the most common in sports and account for significant time loss. Despite being so common, the injury mechanism of hamstring injuries remains to be determined.

Purpose

To investigate the hamstring injury mechanism by conducting a systematic review.

Study design

A systematic review following the PRISMA statement.

Methods

A systematic search was conducted using PubMed, EMBASE and the Cochrane Library. Studies 1) written in English and 2) deciding on the mechanism of hamstring injury were eligible for inclusion. Literature reviews, systematic reviews, meta-analyses, conference abstracts, book chapters and editorials were excluded, as well as studies where the full text could not be obtained.

Results

Twenty-six of 2372 screened original studies were included and stratified to the mechanism or methods used to determine hamstring injury: stretch-related injuries, kinematic analysis, electromyography-based kinematic analysis and strength-related injuries. All studies that reported the stretch-type injury mechanism concluded that injury occurs due to extensive hip flexion with a hyperextended knee. The vast majority of studies on injuries during running proposed that these injuries occur during the late swing phase of the running gait cycle.

Conclusion

A stretch-type injury to the hamstrings is caused by extensive hip flexion with an extended knee. Hamstring injuries during sprinting are most likely to occur due to excessive muscle strain caused by eccentric contraction during the late swing phase of the running gait cycle.

Level of evidence

Level IV

Hamstring Injury Trends in Major and Minor League Baseball: Epidemiological Findings From the Major League Baseball Health and Injury Tracking System

Background:

Hamstring strains are the most common injury for professional baseball players and can result in significant time on the disabled list. To date, no study has reported the current trends in hamstring strains in professional baseball.

Hypothesis:

Professional baseball players would have an increased incidence of hamstring strains from 2011 through 2016.

Study Design:

Descriptive epidemiology study.

Methods:

Injury data were prospectively collected from 2011 through 2016 for every Major League Baseball (MLB) and Minor League Baseball (MiLB) team and was recorded in the MLB Health and Injury Tracking System. Data collected for this study included date of injury, activity during injury, time lost, primary injury or reinjury status, and imaging findings as well as player demographic information related to level of play, age, and position for all hamstring injury events. Injury rates were reported as hamstring injuries per number of games.

Results:

From 2011 to 2016, there were 2633 hamstring strains in professional baseball players. The rate of hamstring strains increased in MLB from a low of 1 injury every 39 games in 2011 to a high of 1 injury every 30 games in 2016. In MiLB, there were 2192 hamstring strains, with 1 injury every 35 games in 2011 compared with 1 injury every 30 games in 2016. The majority of injuries occurred in the infielder positions (37.5%) and resulted from base running (>50%), most commonly from home to first base. The most common hamstring injury was a grade 2 injury to the distal biceps femoris. The mean time missed after a hamstring injury was 14.5 days. Grade 3 and grade 2 hamstring strains resulted in significantly more days missed compared with grade 1 injuries (P = .005 and P = .002, respectively). The rate of recurrent hamstring injuries was 16.3% for MLB and 14.2% for MiLB. Recurrent hamstring injuries resulted in more time lost than primary injuries (mean, 16.4 vs 14.5 days, respectively; P = .02). A total of 42 injuries were treated with platelet-rich plasma, and 19 were treated with surgery. The number of injuries treated with platelet-rich plasma increased in successive years.

Conclusion:

The rate of hamstring strains in professional baseball players has increased over the past 6 years and has resulted in a significant loss of playing time. Study results indicated that these injuries are affected by injury characteristics, position played, running to first base, seasonal timing, and history of hamstring injuries.

Imaging of hip and thigh muscle injury: a pictorial review

Muscle injuries of the hip and thigh are a highly relevant issue in competitive sports imaging. The gold standard in diagnostic imaging of muscle injuries is magnetic resonance imaging (MRI). Radiologists need to be familiar with typical MRI findings in order to accurately detect and classify muscle injuries. Proper interpretation of the findings is crucial, especially in elite athletes. In soccer players, muscle injuries of the hip and thigh are the most common reason for missing a game.The present pictorial review deals with the diagnostic assessment, especially MRI, of muscle injuries of the hip and thigh. Typical MR findings in muscle injuries include edema, hematoma, and tendinous avulsion as well as partial or complete muscle tear. To estimate the time to return to play, a grading into three groups-muscle strain, partial tear, complete tear-has traditionally been used. Taking into account the most recent literature, there are other prognostic factors such as the longitudinal length of a tear, the tendon's intramuscular component, or persisting edema.

Surgical Management of Recurrent Musculotendinous Hamstring Injury in Professional Athletes

BACKGROUND

Hamstring injury is the most common muscular lesion in athletes. The conservative treatment is well described, and surgical management is often indicated for proximal tendinous avulsions. To our knowledge, no surgical treatment has been proposed for failure of conservative treatment in musculotendinous hamstring lesions.

PURPOSE

To describe the surgical management of proximal and distal hamstring musculotendinous junction lesions in professional athletes after failure of conservative treatment.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A consecutive series of 10 professional athletes, including 4 soccer players, 4 rugby players, and 2 handball players, underwent surgical intervention between October 2010 and June 2014 for the treatment of recurrent musculotendinous hamstring injuries. All athletes had failed at least 3 months of conservative treatment for a recurrent musculotendinous hamstring injury. Surgical resection of the musculotendinous scar tissue was performed using a longitudinal muscular suture. Lower Extremity Functional Scale (LEFS) and Marx scores were obtained at the 3-month follow-up, and a final phone interview was completed to determine recurrence of hamstring injury and return to previous level of play.

RESULTS

The mean age at surgery was 25.2 years (range, 19-35 years). The musculotendinous hamstring lesions involved 8 semitendinosus and 2 biceps femoris, with 6 injuries located proximally and 4 distally. Conservative treatment lasted a mean 5.1 months (range, 3-9 months) after last recurrence, and the patients had an average of 2.7 (range, 2-5) separate incidents of injury recurrence before surgical intervention was decided upon. At the 3-month follow-up, all patients had Marx activity scores of 16 and LEFS scores of 80. All 10 patients returned to the same level of play at a mean 3.4 months (range, 2-5 months). At a mean follow-up of 28.7 months, none of the athletes had suffered a recurrence. No surgical complication was encountered.

CONCLUSION

In cases of failed conservative treatment of musculotendinous hamstring lesions, surgical intervention may be a viable treatment option in professional athletes and allows the patient to return to the same level of play.