Strength Measurements in Acute Hamstring Injuries: Intertester Reliability and Prognostic Value of Handheld Dynamometry

Recovery of spatio-temporal gait and functional parameters following unilateral eccentric exercise-induced muscle damage in the hamstrings

OBJECTIVES

This study aimed to analyze how spatiotemporal gait parameters, active knee extension range of motion, muscle activity, and self-perceived function change over a seven-day period in healthy individuals after exercise-induced muscle damage (EIMD) in the hamstrings.

DESIGN

Longitudinal cohort study.

METHODS

Twenty-four healthy males participated in four sessions before and after EIMD (pre-EIMD, 48 h, 96 h, and 168 h post-EIMD). A single-leg deadlift exercise was performed to provoke EIMD in the hamstrings of the dominant leg. Lower limb function perception, spatiotemporal gait parameters, active knee extension range of motion, and electromyographic (EMG) activity of the semitendinosus and biceps femoris muscles during gait and maximal isometric contraction were assessed bilaterally.

RESULTS

At 48 h, the EIMD-side showed reduced step length, active knee extension range of motion, maximal strength and EMG activity compared to baseline (P < 0.042), while increased relative EMG activity in the biceps femoris during gait (P = 0.001). At 96 h, step length and EMG activity on the EIMD-side reached similar values to those at baseline, whereas lower limb function perception and active knee extension range of motion returned to baseline state at 168 h post-EIMD. No changes over time were observed on the control-side.

CONCLUSIONS

Recovery from EIMD requires a multimodal assessment since the different parameters affected by EIMD recover at different paces. Active range of motion appears to be the last variable to fully recover. Self-perceived function should not be considered in isolation as it does not represent complete functional recovery.

Gender-specific hip strength disparities correlate with injury patterns in NCAA men's and women's soccer players

BACKGROUND

In National Collegiate Athletic Association (NCAA) soccer athletes, men have higher rates of hip and groin strains, whereas women have higher rates of knee ligament injuries. Strength imbalances of the hip and thigh, specifically in agonist-antagonist muscles, are known risk factors for these injuries.

OBJECTIVE

To perform hip and thigh strength assessments in NCAA soccer players to evaluate for differences between genders and correlations with gender-specific injury patterns.

DESIGN

With a handheld dynamometer, weight-normalized isometric strength of six muscle groups (hip abductors, hip adductors, hip flexors, hip extensors, knee flexors, knee extensors) was calculated in NCAA soccer players. The strength ratio of each agonist-antagonist muscle was also calculated (hip abductors/adductors, hip flexors/extensors, knee extensors/flexors).

PARTICIPANTS

Thirty-six NCAA soccer players (18 men, 18 women) from a single NCAA Division III institution.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Weight-normalized strength of six muscle groups and their agonist-antagonist strength ratios were compared between genders using linear mixed-effects models.

RESULTS

Compared with male players, female players had decreased weight-normalized strength for hip abduction (0.170 vs. 0.204, p = .012) and hip extension (0.172 vs. 0.211, p = .021). Otherwise, weight-normalized strength was similar between genders. When comparing agonist-antagonist strength ratios, there was a significant difference between female and male players for hip flexion:extension (1.70 vs. 1.35, p = .008), whereas the hip abduction: adduction ratio did not reach statistical significance (1.45 vs. 1.62, p = .080).

CONCLUSIONS

NCAA male and female soccer players had different hip strength profiles that fit their injury patterns. Male NCAA soccer players have higher rates of hip and groin strains, and men in the cohort had strength ratios that were deficient in the hip flexors and adductors compared with women. Female NCAA soccer players have higher rates of knee sprains and anterior cruciate ligament tears, and women in the cohort had strength ratios that were deficient in the hip abductors and extensors, which function to stabilize the knee. These strength disparities could be the focus of future gender-specific soccer injury prevention programs.

Effect of Telerehabilitation-Based Exercise and Education on Pain, Function, Strength, Proprioception, and Psychosocial Parameters in Patients With Knee Osteoarthritis: A Randomized Controlled Clinical Trial

OBJECTIVE

In middle-aged individuals with early-stage knee osteoarthritis, follow-up with remote rehabilitation methods may provide effective clinical outcomes. The present study aimed to investigate the effect of telerehabilitation on pain, function, performance, strength, proprioception, and psychosocial parameters in patients with knee osteoarthritis.

DESIGN

A randomized controlled study was conducted with 54 participants with knee osteoarthritis. All patients were randomized into two groups: the home-based telerehabilitation group ( n = 29) and the home-based paper group ( n = 28). The home exercise program and training were provided with an instruction manual to paper group. The same home exercise and education prescriptions were given to individuals in telerehabilitation group via an online platform. Pain, function, quality of life, physical performance, muscle strength, and proprioception were evaluated at baseline and after 8 wks of intervention. In addition, satisfaction and usability were evaluated at week 8.

RESULTS

Telerehabilitation group demonstrated better improvement in terms of pain, function, quality of life index score, and left extremity proprioception ( P < 0.05). Telerehabilitation group was not superior to paper group in terms of muscle strength and performance tests (except the Five Times Sit to Stand Test) ( P > 0.05).

CONCLUSIONS

The home-based telerehabilitation program was superior to the home-based paper group program for pain, function, quality of life, and proprioception in patients with knee osteoarthritis.

The Effect of the Nordic Hamstring Exercise on Muscle Activity: A Multichannel Electromyography Randomized Controlled Trial

The aim of this study was to evaluate the effect of a Nordic hamstring exercise intervention on biceps femoris long head, semitendinosus, and semimembranosus muscle's activity and relative contributions through multichannel electromyography. Twenty-four injury-free male basketball players (mean age 20 [3] y) were randomly assigned to a 12-week intervention (n = 13) or control group (n = 11). The primary outcome measures were normalized muscle activity (percentage of maximal voluntary isometric contraction, %MVIC) and relative contribution of hamstring muscles over 12 weeks. No effects were found on any of the primary outcome measures. Between-group differences over 12 weeks were 2.7%MVIC (95% confidence interval 95% CI, -0.7 to 6.1) for the biceps femoris long head, 3.4%MVIC (95% CI, -1.4 to 8.2) for the semitendinosus, and 0.8%MVIC (95% CI, -3.0 to 4.6) for the semimembranosus, P = .366. Between-group differences over 12 weeks were 1.0% relative contribution (%con; 95% CI, -3.0 to 5.1) for the biceps femoris long head, 2.2% relative contribution (95% CI, -2.8 to 7.2) for the semitendinosus, and -3.3% relative contribution (95% CI, -6.4 to -0.1) for the semimembranosus P = .258. A positive value implies a higher value for the Nordic group. A Nordic hamstring exercise intervention did not affect the level of muscle activity and relative contribution of hamstring muscles in performance of the Nordic hamstring exercise.

The Single Leg Bridge Test does not replace handheld dynamometer hamstring tests in a clinical setting

OBJECTIVE

To examine the correlation of Single Leg Bridge Test (SLBT) scores with maximum isometric strength values obtained in handheld dynamometer (HHD) hamstring tests performed in a clinical setting.

DESIGN

Cross-sectional study.

SETTING

Physical therapy clinic.

PARTICIPANTS

Fifty healthy and physically active men.

MAIN OUTCOME MEASURES

Correlation between SLBT scores and force values found in three HHD hamstring tests: test 'A', volunteer in prone with hip in neutral position and the knee flexed at ∼90°; test 'B', volunteer in supine with hip and knee flexed at ∼90°; and test 'C', volunteer in the same position used to perform the SLBT.

RESULTS

The volunteers' SLBT score was 27.55 ± 7.81 repetitions. The SLBT scores were poorly associated with mean (r = 0.246) and peak (r = 0.321) results provided by HHD test 'A'. There were no significant correlations between the SLBT scores and mean or peak values obtained in tests 'B' and 'C' (p > 0.05). Similarly, the SLBT between-limb asymmetry was not associated with asymmetries found in HHD hamstring tests (p > 0.05).

CONCLUSIONS

HHD hamstring tests should not be replaced by the SLBT. We recommend for clinicians to applying such tests in a complementary way to assess the hamstring's functional status.

Sensory, functional and electromyographic variables show different recovery patterns over a seven day period following exercise-induced pain in the hamstrings

BACKGROUND

Delayed-onset muscle soreness (DOMS) is common after unaccustomed exercises and can restrict performance if intense physical activities are performed while the muscle is still sore. This study aimed to evaluate the recovery process following exercise-induced DOMS over a seven-day period by evaluating sensory, functional, and electromyographic parameters.

METHODS

Twenty-four healthy males participated in four experimental sessions (Day-0, Day-2, Day-4, Day-7). Pain perception, pressure pain sensitivity, active range of motion, maximal isometric strength, and muscle activity of the hamstrings during the maximal isometric contraction were assessed bilaterally at each session. A single-leg deadlift eccentric exercise (5-sets of 20-reps) was performed at the end of Day-0 to induce DOMS in the dominant leg.

FINDINGS

At Day-2, the DOMS-side showed increased pain sensitivity and decreased active range of motion, strength and muscle activity compared to Day-0 (P < 0.015). Muscle activity on the DOMS-side reached similar values than at baseline on Day-4, whereas pain perception, pressure pain sensitivity, maximal isometric strength, and active range of motion had returned to the baseline state on Day-7. No changes over time were observed on the control-side, showing all variables an excellent reliability between values at Day-0 and Day-7 (Intraclass Correlation Coefficient > 0.90).

INTERPRETATION

Surface electromyographic values during a maximal isometric contraction recover faster than the other parameters. Given the heterogeneous path of altered variables towards DOMS recovery, trainers and clinicians should consider a multimodal assessment, including quantitative sensory and functional measures in addition to the subjective perception of recovery.

Effects of left thigh blood flow restriction exercise on muscle strength and golf performance in amateur golfers

This study aimed to investigate the effect of lower-extremity strengthening exercise (LSE) with and without blood flow restriction (BFR) on the left thigh on golf performance. Eighteen amateur golfers with more than 1 year of golf experience participated in the study and were randomly divided into two groups: LSE+BFR group (LSE with BFR on the left thigh, n=9) and LSE group (LSE without BFR, n=9). The LSEs consisted of squats, lunges, and standing leg curls. All exercises were performed 3 times a week for 6 weeks. Changes in thigh muscle strength, plantar foot pressure (weight transfer), and golf performance, such as club head speed, ball speed, and carry distance were measured before and after the exercise program. Right knee extension (P<0.001) and left knee extension and flexion (P<0.001) strength were higher in the LSE+BFR group than in the LSE group. The changes in plantar foot pressure confirmed that smooth weight transfer appeared in E1 (event 1) (address) (P<0.05) of the LSE+BFR group, which confirmed that the carry distance (P<0.05) of the LSE+BFR group improved after the exercise program. The results of this study showed that BFR muscle strengthening exercise are more effective than basic simple muscle strengthening exercise in improving golf performance through muscle strength and weight transfer improvement.

Early introduction of high-intensity eccentric loading into hamstring strain injury rehabilitation

OBJECTIVES

This study aimed to investigate the number of days following hamstring strain injury (HSI) taken to introduce high-intensity eccentric loading (HIEL) into rehabilitation based on exercise-specific progression criteria, and whether pain resolution during isometric knee flexion strength testing occurred before or after this milestone.

DESIGN

Cohort study.

METHODS

We included 42 men (mean ± sd; age = 26 ± 5 years; height = 181 ± 8 cm; mass = 86 ± 12 kg) with HSIs, who performed fully supervised rehabilitation twice per week until they met return to play clearance criteria. Isometric knee flexion strength testing was completed before every rehabilitation session and HIEL was introduced via the Nordic hamstring exercise and unilateral slider once participants could perform a bilateral slider through full eccentric knee flexion range of motion. We reported the median (IQR) number of days following HSI taken to introduce HIEL, along with participant's pain rating during isometric knee flexion strength testing before that rehabilitation session. We also reported the median (IQR) number of days following HSI taken for participants to achieve pain resolution during isometric knee flexion.

RESULTS

HIEL was introduced 5 (2-8) days following HSI, despite 35/42 participants reporting pain during isometric knee flexion strength testing immediately prior to that rehabilitation session, which was rated as 3.5 (3-5) on a 0-10 numeric rating scale. Pain resolution during isometric knee flexion strength testing was achieved 11 (9-13) days following HSI.

CONCLUSION

HIEL can be safely introduced into early HSI rehabilitation based on exercise-specific progression criteria, without needing to wait for pain resolution during isometric knee flexion strength testing before doing so.

Hamstring Strain Injury in Athletes

Hamstring strain injury (HSI) may result in considerable impairment, activity limitation, and participation restriction, including time lost from competitive sports. This CPG includes sports-related overloading and overstretching injuries to myofascial or musculotendinous structures in any combination of the 3 hamstring muscles (the semitendinosus, semimembranosus, and biceps femoris). J Orthop Sports Phys Ther 2022;52(3):CPG1-CPG44. doi:10.2519/jospt.2022.0301.

Hamstring Strain Injury Rehabilitation

Hamstring strain injuries are common among athletes and often require rehabilitation to prepare players for a timely return to sport performance while also minimizing reinjury risk. Return to sport is typically achieved within weeks of the injury; however, subsequent athlete performance may be impaired, and reinjury rates are high. Improving these outcomes requires rehabilitation practitioners (eg, athletic trainers and physical therapists) to understand the causes and mechanisms of hamstring strain injury, know how to perform a thorough clinical examination, and progress loading to the site of injury safely and effectively. This narrative review discusses current clinical concepts related to these aspects of rehabilitation for hamstring strain injury, with the aim of helping practitioners improve athletes' outcomes. Collectively, this knowledge will inform the implementation of evidence-based rehabilitation interventions.

Proximal hamstring tendon avulsions: comparable clinical outcomes of operative and non-operative treatment at 1-year follow-up using a shared decision-making model

OBJECTIVE

To prospectively evaluate 1-year clinical and radiological outcomes after operative and non-operative treatment of proximal hamstring tendon avulsions.

METHODS

Patients with an MRI-confirmed proximal hamstring tendon avulsion were included. Operative or non-operative treatment was selected by a shared decision-making process. The primary outcome was the Perth Hamstring Assessment Tool (PHAT) score. Secondary outcome scores were Proximal Hamstring Injury Questionnaire, EQ-5D-3L, Tegner Activity Scale, return to sports, hamstring flexibility, isometric hamstring strength and MRI findings including proximal continuity.

RESULTS

Twenty-six operative and 33 non-operative patients with a median age of 51 (IQR: 37-57) and 49 (IQR: 45-56) years were included. Median time between injury and initial visit was 12 (IQR 6-19) days for operative and 21 (IQR 12-48) days for non-operative patients (p=0.004). Baseline PHAT scores were significantly lower in the operative group (32±16 vs 45±17, p=0.003). There was no difference in mean PHAT score between groups at 1 year follow-up (80±19 vs 80±17, p=0.97). Mean PHAT score improved by 47 (95% CI 39 to 55, p<0.001) after operative and 34 (95% CI 27 to 41, p<0.001) after non-operative treatment. There were no relevant differences in secondary clinical outcome measures. Proximal continuity on MRI was present in 20 (95%, 1 recurrence) operative and 14 (52%, no recurrences) non-operative patients (p=0.008).

CONCLUSION

In a shared decision-making model of care, both operative and non-operative treatment of proximal hamstring tendon avulsions resulted in comparable clinical outcome at 1-year follow-up. Operative patients had lower pretreatment PHAT scores but improved substantially to reach comparable PHAT scores as non-operative patients. We recommend using this shared decision model of care until evidence-based indications in favour of either treatment option are available from high-level clinical trials.

Reliability and validity of hand-held dynamometry for assessing lower limb muscle strength

BACKGROUND: Hand-held dynamometry (HHD) is used to assess muscle strength in various patient populations, but many variations in protocols exist. OBJECTIVE: First, to systematically develop a protocol of HHD for all lower limb muscle groups and evaluate intra-rater reliability; second, to validate HHD with fixed dynamometry for the knee flexor and extensor muscles. METHODS: Thirty healthy young adults (women: men – 15:15) participated in two testing sessions. HHD of 12 lower limb muscle groups was performed in both sessions, while fixed dynamometry of knee muscle groups was performed only in the second session. RESULTS: The intra-rater reliability of HHD was good for five muscle groups and excellent for seven muscle groups (ICC3, k= 0.80–0.96). The criterion validity of HHD ranged from very good to excellent for the knee flexors (r= 0.77–0.89) and from good to very good for the knee extensors (r= 0.65–0.78). However, peak moment values for the knee extensor muscles were underestimated by 32% (p< 0.001). CONCLUSIONS: The proposed HHD protocol provides reliable and valid measurements of lower limb muscle isometric strength in healthy adults, which may also be used to test patients with mild muscle strength deficits. However, possible underestimation of absolute strength must be considered when interpreting the results of knee extensors or other large muscles.

Assessment of Isometric Knee Flexor Strength Using Hand-Held Dynamometry in High-Level Rugby Players Is Intertester Reliable

OBJECTIVE

To assess intertester reliability of isometric knee flexor strength testing in high-level rugby players with testers of different physical capacity and different methods of dynamometer fixation.

DESIGN

Reliability study.

PATIENTS

Thirty noninjured high-level (Tegner Activity Score ≥9) rugby players, free from hamstring injury in the previous 2 months.

ASSESSMENT

Isometric knee flexor strength (in N) in prone 0/15 degrees (hip/knee flexion) and supine 90/90 degrees position. Tests were performed by 1 female and 2 male testers whose upper-body strength was measured with a 6-repetition maximum bench press test. The prone 0/15 degrees measurement was performed with manual and external belt fixation of the dynamometer.

MAIN OUTCOME MEASURES

Absolute and relative intertester reliability were calculated using intraclass correlation coefficient (ICC) and minimal detectable change. Paired t-tests were used to identify systematic measurement error between testers and to test for a difference in recorded knee flexor strength between methods of dynamometer fixation.

METHODS

Isometric knee flexor strength was measured in prone 0/15 degrees (hip/knee flexion) and supine 90/90 degrees position.

RESULTS

Good intertester reliability was found for all pairwise comparisons (ICC 0.80-0.87). MDCs (as percentage of mean strength) ranged from 15.2% to 25.4%. For tester couples where systematic error was identified, Bland-Altman plots and Pearson correlation coefficients demonstrated no statistically significant correlation between mean knee flexor strength and between-tester difference. There was no significant difference in isometric knee flexor strength between manual and belt fixation of the dynamometer.

CONCLUSIONS

In strong high-level rugby players, hand-held dynamometry for isometric knee flexor strength assessment in prone 0/15 degrees and supine 90/90 degrees position is intertester reliable.

Exploring the Perth Hamstring Assessment Tool and Lower Extremity Functional Scale in a Proximal Hamstring Avulsion Cohort: A Cross-sectional Study

BACKGROUND

The goal of treatment for a proximal hamstring avulsion (PHA) is an objectively restored muscle and a subjectively satisfied, pain-free patient at follow-up. Different self-reported and performance-based outcome measures have been used to evaluate recovery, but their validity is poorly investigated.

PURPOSE

To investigate (1) the correlation between the commonly used self-reported outcome measurements, the Perth Hamstring Assessment Tool (PHAT) and the Lower Extremity Functional Scale (LEFS); (2) to what extent these scores can be explained by physical dysfunction as measured by performance-based tests; (3) whether performance-based tests can discriminate between the injured and uninjured extremity; and (4) which activity limitations are perceived by patients several years after the injury.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 3.

METHODS

We included a consecutive series of patients treated for or diagnosed with PHA in our department between 2007 and 2016 having at least 2 tendons avulsed from the ischial tuberosity. Participants attended 2 study visits, answered questionnaires (PHAT, LEFS, and Patient-Specific Functional Scale [PSFS]), and performed physical performance-based tests (single-leg hop tests, single-step down test, and isometric and isokinetic strength tests).

RESULTS

A total of 50 patients were included (26 men [52%], 24 women [48%]; mean age, 50.9 years [SD, 9.8 years]). The mean follow-up time was 5.5 years (SD, 2.7 years), and 74% had been surgically treated. The correlation between PHAT and LEFS was strong (r = 0.832) and statistically significant (P < .001). Seven of the performance-based tests exhibited a statistically significant but weak correlation with LEFS (0.340-0.488) and 3 of the tests to PHAT (-0.304 to 0.406). However, only peak torque could significantly discriminate between the extremities. The activity limitation most commonly mentioned in PSFS was running (16 patients [32%]).

CONCLUSION

Although PHAT and LEFS correlated strongly, the correlations between functional tests and the patient-reported outcome scores were weak, and most functional tests failed to discriminate between the injured and uninjured lower extremity in patients with PHA 5 years after injury. In general, patients alleged few activity limitations, but running difficulty was a common sequela after PHA.

No relationship between the nordic hamstring and two different isometric strength tests to assess hamstring muscle strength in professional soccer players

OBJECTIVES

To investigate the relationship between one eccentric and two isometric tests commonly used to assess hamstring strength in professional soccer.

SETTINGS

Professional soccer club.

DESIGN

Cross-sectional study.

PARTICIPANTS

Twenty male professional soccer players.

MAIN OUTCOME MEASURES

Hamstring force was quantified during 3 tests (Nordic hamstring eccentric, 90:20 isometric posterior-chain strength and isometric 15° knee flexion) using a load cell, a handheld dynamometer and a force platform, respectively.

RESULTS

Poor relationships and low concordance were observed between isometric and eccentric tests, showing different ability to discriminate hamstring weakness and asymmetries. The Nordic hamstring test identified between-limb asymmetry >15% in 30% of the players, 25% in the 15° knee flexion and 5% in the 90:20 test. All players obtained different results in the three tests with only one showing asymmetry >15% in two tests.

CONCLUSION

Results obtained in each test cannot inform the others. Mechanical outputs of these tests must be used for particular purposes during the prevention, rehabilitation and monitoring process of hamstring injury. Isometric testing might be preferable during the initial phases of the recovery process of a hamstring injury while the Nordic hamstring test might be used in the last stages or detect muscle weakness/asymmetries in non-injured players.

Females Have Earlier Muscle Strength and Functional Recovery After Bridge-Enhanced Anterior Cruciate Ligament Repair

Background: While a sex effect on outcomes following anterior cruciate ligament (ACL) reconstruction surgery has been previously documented, less is known following bridge-enhanced ACL repair (BEAR). We hypothesized that female sex would have significantly worse early functional outcomes and higher retear rates following primary repair of the ACL enhanced with a tissue-engineered scaffold. Methods: Sixty-five patients (28 males and 37 females), age 14-35 with a complete ACL tear underwent primary repair of the ACL enhanced with a tissue-engineered scaffold (bridge-enhanced ACL repair) within 45 days of injury. International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome (KOOS) scores, as well as instrumented anteroposterior (AP) laxity through KT-1000 testing and functional outcome measures were obtained at time points up to 2 years postoperatively and compared between males and females using mixed model repeated measures analyses and chi square tests. Results: There was no significant sex difference on the postoperative IKDC Subjective Score at 3, 6, 12, or 24 months or any of the five KOOS scores at 12 and 24 months. Instrumented AP laxity testing demonstrated mean (standard deviation) side-to-side differences that were similar in the two sexes at 2 years; 1.7 (2.7) mm and 1.5 (3.7) mm in females and males, respectively, p = 0.72. At 6 months postoperatively, males had a larger deficit in hamstring strength on the operated leg (14.0% vs. 1.7%; p = 0.03) and a larger deficit in quadriceps strength on the operated leg (11.3% vs. 2.0%; p = 0.004); however, no sex difference was noted at 12 or 24 months. Females demonstrated superior single leg hop testing at 6 and 12 months ([91.3% vs. 78.1%, p = 0.001], [96.9% vs. 87.0%, p = 0.01] respectively). There were no significant sex differences on ipsilateral (males; 14.3% vs. females; 13.9%, p = 1.00) or contralateral (males; 3.6% vs. females; 2.8%, p = 1.00) ACL reinjury rates. Conclusions: Female subjects had better hamstring and quadriceps strength indices at 6 months than males as well as better hop test results at the 6 and 12-month time period. Despite this, there was no significant sex difference on patient-reported outcomes and objective AP laxity testing at time points up to 2 years postoperatively. Impact statement This is the first study comparing sex specific outcomes following the bridge-enhanced ACL repair technique (BEAR). The results of this study suggest that females have earlier recovery of both muscle strength and functional outcomes compared to their male counterparts. This is an important finding when considering future modifications to postoperative care and rehabilitation in females and males following this tissue-engineered BEAR technique.

The proximal hamstring avulsion clinical trial (PHACT)-a randomised controlled non-inferiority trial of operative versus non-operative treatment of proximal hamstrings avulsions: study protocol

INTRODUCTION

The treatment of proximal hamstring avulsions is controversial. While several trials have investigated the outcome for patients treated surgically, there is today no prospective trial comparing operative treatment with non-operative treatment. This protocol describes the design for the proximal hamstring avulsion clinical trial (PHACT)-the first randomised controlled trial of operative versus non-operative treatment for proximal hamstring avulsions.

METHODS AND ANALYSIS

PHACT is a multicentre randomised controlled trial conducted across Sweden, Norway and Finland. Eligible patients (60 participants/treatment arm) with a proximal hamstring avulsion of at least two of three tendons will be randomised to either operative or non-operative treatment. Participants allocated to surgery will undergo reinsertion of the tendons with suture anchors. The rehabilitation programme will be the same for both treatment groups. When patient or surgeon equipoise for treatment alternatives cannot be reached and randomisation therefore is not possible, patients will be invited to participate in a parallel observational non-randomised cohort. The primary outcome will be the patient-reported outcome measure Perth hamstring assessment tool at 24 months. Secondary outcomes include the Lower Extremity Functional Score, physical performance and muscle strength tests, patient satisfaction and MR imaging. Data analysis will be blinded and intention-to-treat analysis will be preformed.

ETHICS AND DISSEMINATION

Ethical approval has been granted by the Ethical Committee of Uppsala University (DNR: 2017-170) and by the Norwegian ethical board (REC: 2017/1911). The study will be conducted in agreement with the Helsinki declaration. The findings will be disseminated in peer-reviewed publications.

TRIAL REGISTRATION NUMBER

NCT03311997.

Bridge-Enhanced Anterior Cruciate Ligament Repair: Two-Year Results of a First-in-Human Study

Background

Bridge-enhanced anterior cruciate ligament repair (BEAR) combines suture repair of the anterior cruciate ligament (ACL) with a specific extracellular matrix scaffold (the BEAR scaffold) that is placed in the gap between the torn ends of the ACL to facilitate ligament healing.

Purpose/Hypothesis

The purpose of this study was to report the 12- and 24-month outcomes of patients who underwent the BEAR procedure compared with a nonrandomized concurrent control group who underwent ACL reconstruction (ACLR) with an autograft. We hypothesized that the BEAR group would have physical examination findings, patient-reported outcomes, and adverse events that were similar to those of the ACLR group.

Study Design

Cohort study; Level of evidence, 2.

Methods

Ten patients underwent BEAR, and 10 underwent ACLR with a 4-stranded hamstring autograft. At 24 months, 9 of the 10 BEAR patients and 7 of the 10 ACLR patients completed a study visit. Outcomes reported included International Knee Documentation Committee (IKDC) subjective and objective results, knee anteroposterior (AP) laxity findings via an arthrometer, and functional outcomes.

Results

There were no graft or repair failures in the first 24 months after surgery. The IKDC subjective scores in both groups improved significantly from baseline (P < .0001) at 12 and 24 months, to 84.6 ± 17.2 in the ACLR group and to 91.7 ± 11.7 in the BEAR group. An IKDC objective grade of A (normal) was found in 44% of patients in the BEAR group and in 29% of patients in the ACLR group at 24 months; no patients in either group had C (abnormal) or D (severely abnormal) grades. Arthrometer testing demonstrated mean side-to-side differences in AP laxity that were similar in the 2 groups at 24 months (BEAR, 1.94 ± 2.08 mm; ACLR, 3.14 ± 2.66 mm). Functional hop testing results were similar in the 2 groups at 12 and 24 months after surgery. Hamstring strength indices were significantly higher in the BEAR group compared with the ACLR group (P = .0001).

Conclusion

In this small, first-in-human study, BEAR produced similar outcomes to ACLR with a hamstring autograft. BEAR may result in knee stability and patient-reported outcomes at 2 years sufficient to warrant longer term studies of efficacy in larger groups of patients.

Can a Clinical Examination Demonstrate Intramuscular Tendon Involvement in Acute Hamstring Injuries?

Background:

Involvement of the intramuscular (central) tendon in acute hamstring injuries, as detected on magnetic resonance imaging (MRI), may prolong recovery times. To date, it is unclear whether hamstring injuries exhibiting intramuscular tendon involvement can be identified though routine clinical examinations that assess flexibility and strength.

Purpose:

To test whether MRI-detected intramuscular tendon involvement could be identified by a clinical assessment of muscle strength and flexibility.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

Participants were drawn from a multicenter randomized controlled trial on the effect of platelet-rich plasma in acute hamstring injuries. Clinical parameters assessed within 5 days of injury were active knee extension and passive straight-leg raise for hamstring flexibility and isometric knee flexion force with 15° and 90° of knee flexion. Also, 1.5-T MRI of the thigh was performed within 5 days of injury and was evaluated for the presence of different types of intramuscular tendon involvement. One-way analysis of variance was used to determine whether clinical parameters could discriminate injuries with intramuscular tendon involvement from those without such involvement.

Results:

A total of 74 acute hamstring injuries were included, with 52 (70.3%) injuries affecting the myotendinous junction. Injuries exhibiting intramuscular tendon discontinuity on MRI had an increased mean absolute flexibility deficit for active knee extension (20.4° ± 14.9° vs 10.7° ± 9.0°, respectively; P = .006) and decreased mean strength at 15° (62.2 ± 26.7 N vs 76.6 ± 22.5 N, respectively; P = .05) compared with injuries without intramuscular tendon discontinuity. Flexibility and strength showed major overlap and variance among injuries with and without intramuscular tendon involvement.

Conclusion:

Hamstring flexibility and strength cannot be used to discriminate the presence of intramuscular tendon involvement.