Comparison of muscle and tendon stiffness, jumping ability, muscle strength and fatigue in the plantar flexors

FGF gene expression in injured tendons as a prognostic biomarker of 1-year patient outcome after Achilles tendon repair

PURPOSE

Healing outcome after Achilles Tendon Rupture (ATR) is variable and unsatisfactory. Many ATR patients still exhibit pain, functional deficits and limitations in walking one-year post-surgery. The present study was designed to investigate the association between the expression of healing biomarkers and patient outcome after ATR.

METHODS

Tendon biopsies were collected from 25 ATR patients during surgery. At 1-year post surgery, all patients completed questionnaires; Achilles tendon Total Rupture Score (ATRS) and Foot and Ankle Outcome Score (FAOS), and were tested for functional outcomes by heel-rise test. In biopsies, FGF, COL III, FN, COL I and MMP-9 mRNA levels were assessed by quantitative RT-PCR while protein expression was studied by immunohistochemistry (IHC).

RESULTS

Our analysis confirmed the presence of FGF, COL III, FN, COL I and MMP-9 at mRNA and protein levels in tendon biopsies. FGF gene expression associated positively with improved total ATRS and better functional outcomes. Additionally, FGF mRNA levels were associated with less pain, less running limitations and less loss in physical activity. In addition, higher COL III mRNA expression was associated with more tendon strength.

CONCLUSION

Our findings indicate that FGF gene expression is associated with improved patient-reported outcome. FGF expression in surgical biopsies could potentially be used to assist the prognostic evaluation of patient outcome and may be used as a predictor for healing. However, further studies are needed to evaluate the role of FGF in Achilles tendon healing.

LEVEL OF EVIDENCE

II.

A Prospective Cohort Study on the Effect of a Balance Training Program, Including Calf Muscle Strengthening, in Community-Dwelling Older Adults

BACKGROUND

Falls are the number 1 cause of injury, fractures, and death among the older population. In fact, one-third of adults older than 60 years will experience 1 or more falls annually. Factors including inactivity and decreased mobility are associated with overall declines in strength, balance, and functional mobility in older adults.

PURPOSE

The purpose of this study was to evaluate the effect of a balance training program, including calf muscle strengthening, in community-dwelling older adults and to evaluate how calf muscle strength correlates with risk factors for falls.

METHODS

Community-dwelling older adults from a local senior center were invited to participate in a 5-week (10 sessions), 1-on-1, balance training program, which included calf muscle strengthening. All the participants were evaluated before and after the intervention. The outcome measures were static balance, unilateral heel-rise test, Timed Up and Go test (TUG), the 30-second Chair Stand Test (30-sCST), and the Activity Balance Confidence Scale.

RESULTS

Twenty-eight participants (6 males and 22 females) mean (standard deviation) age of 78 years were included in the study and completed the baseline evaluation. Eight participants did not complete the study. Static balance with eyes closed, heel rise, TUG, 30-sCST, and the Activity Balance Confidence Scale improved significantly (P < .05) following treatment compared with the baseline evaluation. The heel-rise ability correlated significantly (P < .05) with TUG (r = -0.484 to -0.528) and 30-sCST (r = 0.501-0.595). Sixty-three percent of the participants performed 10 reps or less of the unilateral heel rise on the right side and 60% on the left side. None of the participants who performed 10 reps or more of the unilateral heel rise had a high risk of falls based on the TUG.

CONCLUSIONS

A balance training program that includes calf muscle strengthening performed twice a week for 5 weeks resulted in significant improvements in calf muscle strength, functional performance and balance, as well as a significant improvement in balance confidence. The results from this study identify the importance unilateral calf muscle strength has to falls risk among older adults.

Intrarater reliability and agreement of linear encoder derived heel-rise endurance test outcome measures in healthy adults

A linear encoder measuring vertical displacement during the heel-rise endurance test (HRET) enables the assessment of work and maximum height in addition to the traditional repetitions measure. We aimed to compare the test-retest reliability and agreement of these three outcome measures. Thirty-eight healthy participants (20 females, 18 males) performed the HRET on two occasions separated by a minimum of seven days. Reliability was assessed by the intraclass correlation coefficient (ICC) and agreement by a range of measures including the standard error of measurement (SEM), coefficient of variation (CV), and 95% limits of agreement (LoA). Reliability for repetitions (ICC=0.77 (0.66, 0.85)) was equivalent to work (ICC=0.84 (95% CI 0.76, 0.89)) and maximum height (ICC=0.85 (0.77, 0.90)). Agreement for repetitions (SEM=6.7 (5.8, 7.9); CV=13.9% (11.9, 16.8%); LoA=-1.9±37.2%) was equivalent to work (SEM=419J (361, 499J); CV=13.1% (11.2, 15.8%); LoA=0.1±34.8%) with maximum height superior (SEM=0.8cm (0.6, 1.0cm); CV=6.6% (5.7, 7.9%); LoA=1.3±17.1%). Work and maximum height demonstrated acceptable reliability and agreement that was at least equivalent to the traditional repetitions measure.

Microcirculation after Achilles tendon rupture correlates with functional and patient-reported outcomes

Patients with acute Achilles tendon rupture (ATR) display an extended healing process with varying clinical outcome. Poor microcirculatory blood flow has been suggested to be a significant factor for the healing process. However, whether microcirculation may predict healing outcome has been mostly unknown. Therefore, we investigated whether blood flow in the Achilles tendon may be associated with patient-reported and functional outcomes after ATR. In vivo laser-Doppler flowmetry was used to assess microvascular blood flow bilateral in the Achilles tendons, during post-occlusive reactive hyperemia, of nine patients with acute total ATR at 2 weeks post-operatively. At 3 months post-operatively, patient-reported outcome was assessed using Achilles tendon Total Rupture Score (ATRS). At 1 year a uniform outcome score, Achilles Combined Outcome Score (ACOS), was obtained by combining validated, independent, patient-reported (ATRS), and functional outcome (heel-rise test) measures. An improved combined patient-reported and functional outcome, ACOS, at 1 year was significantly correlated with higher maximum blood flow (r=.777, P=.040) in the injured limb. Furthermore, enhanced patient-reported outcome, ATRS, at 3 months, was associated with an elevated ratio of maximum to resting blood flow (r=.809, P=.015) in the uninjured limb. Blood flow in early tendon healing is associated with long-term patient-reported and functional outcomes after ATR. The microcirculatory blood flow of both the healing and contralateral Achilles tendon seems to determine the healing potential after injury.

Ageing, deep vein thrombosis and male gender predict poor outcome after acute Achilles tendon rupture

AIMS

Patients with an acute Achilles tendon rupture (ATR) take a long time to heal, have a high incidence of deep vein thrombosis (DVT) and widely variable functional outcomes. This variation in outcome may be explained by a lack of knowledge of adverse factors, and a subsequent shortage of appropriate interventions.

PATIENTS AND METHODS

A total of 111 patients (95 men, 16 women; mean age 40.3, standard deviation 8.4) with an acute total ATR were prospectively assessed. At one year post-operatively a uniform outcome score, Achilles Combined Outcome Score (ACOS), was obtained by combining three validated, independent, outcome measures: Achilles tendon Total Rupture Score, heel-rise height test, and limb symmetry heel-rise height. Predictors of ACOS included treatment; gender; age; smoking; body mass index; time to surgery; physical activity level pre- and post-injury; symptoms; quality of life and incidence of DVT.

RESULTS

There were three independent variables that correlated significantly with the dichotomised outcome score (ACOS), while there was no correlation with other factors. An age of less than 40 years old was the strongest independent predictor of a good outcome one year after ATR (odds ratio (OR) 0.20, 95% confidence interval (CI) 0.08 to 0.51), followed by female gender (OR) 4.18, 95% CI 1.01 to 17.24). Notably, patients who did not have a DVT while immobilised post-operatively had a better outcome (OR 0.31, 95% CI 0.12 to 0.80).

CONCLUSION

Over the age of 40 years, male gender and having a DVT while immobilised are independent negative predictors of outcome in patients with an acute ATR. Cite this article: Bone Joint J 2016;98-B:1635-41.

Procollagen markers in microdialysate can predict patient outcome after Achilles tendon rupture

Objective

Patients who sustain acute Achilles tendon rupture (ATR) exhibit variable and mostly impaired long-term functional, and patient-reported outcomes. However, there exists a lack of early predictive markers of long-term outcomes to facilitate the development of improved treatment methods. The aim of this study was to assess markers of tendon callus production in patients with ATR in terms of outcome, pain, and fatigue.

Study design and setting

Prospective cohort study; level of evidence 2. Outpatient orthopaedic/sports medicine department.

Patients

A total of 65 patients (57 men, 8 women; mean age 41±7 years) with ATR were prospectively assessed.

Assessments

Markers of tendon callus production, procollagen type I N-terminal propeptide (PINP) and procollagen type III N-terminal propeptide (PIIINP), were assessed 2 weeks postoperatively using microdialysis followed by enzymatic quantification. Normalised procollagen levels (n-PINP and n-PIIINP) were calculated as the ratio of procollagen to total protein content. Pain and fatigue were assessed at 1 year using reliable questionnaires Achilles tendon Total Rupture Score (ATRS).

Results

Patients exhibited fatigue (77.6%) and pain (44.1%) to some extent. Higher levels of n-PINP (R=0.38, p=0.016) and n-PIIINP (R=0.33, p=0.046) were significantly associated with less pain in the limb. Increased concentrations of PINP (R=−0.47, p=0.002) and PIIINP (R=−0.37, p=0.024) were related to more self-reported fatigue in the leg. The results were corroborated by multiple linear regression analyses.

Conclusions

Assessment of procollagen markers in early tendon healing can predict long-term patient-reported outcomes after ATR. These novel findings suggest that procollagen markers could be used to facilitate the development of improved treatment methods in patients who sustain ATR.

Trial registration numbers

NCT01317160: Results. NCT02318472: Pre-results.

Outcome Evaluation in Tendinopathy: Foundations of Assessment and a Summary of Selected Measures

Synopsis Clinical measurement studies that address outcome evaluation for patients with tendinopathy should consider conceptual, clinical, practical, and measurement issues to guide the selection of valid measures. Clinical outcomes reported in research studies can provide benchmarks that assist with interpretation of scores during clinical decision making. Given the pathophysiology and functional impacts of tendinopathy, there is a need for outcome measures that assess physical impairments, activity performance, and patient-reported symptoms and function. Tendinopathy-specific patient-reported outcome measures have been shown to be superior to more generic tools for some conditions, such as lateral epicondyle tendinopathy (Patient-Rated Tennis Elbow Evaluation) and Achilles tendinopathy (Victorian Institute of Sport Assessment-Achilles), whereas both generic shoulder outcome measures and disease-specific measures perform similarly in individuals with rotator cuff tendinopathy. A patient-reported outcome measure that captures pain and limitation in function should be fundamental to outcome evaluation in patients with tendinopathy. The current measurement literature does not yet provide comprehensive empirical data to define optimal outcome measures for all types of tendinopathy. This article reviews concepts, instruments, and measurement properties that should provide clinicians with a foundation for assessment of condition severity and treatment outcomes in patients with tendinopathy. J Orthop Sports Phys Ther 2015;45(11):950-964. Epub 15 Oct 2015. doi:10.2519/jospt.2015.6054.

Active muscle stiffness in the human medial gastrocnemius muscle in vivo

The aims of this study were to 1) directly assess active muscle stiffness according to actual length changes in muscle fibers (fascicles) during short range stretching; and 2) compare actual measured active muscle and tendon stiffness using ultrasonography with the stiffness of active (i.e., muscle) and passive (i.e., tendon) parts in series elastic component of plantar flexors using the alpha method. Twenty-four healthy men volunteered for this study. Active muscle stiffness in the medial gastrocnemius muscle was calculated according to changes in estimated muscle force and fascicle length during fast stretching after submaximal isometric contractions [10, 30, 50, 70, and 90% maximal voluntary contractions (MVC)]. Using the variables measured during this fast stretch experiment, the stiffness of active (i.e., muscle) and passive (i.e., tendon) parts in plantar flexors was assessed using alpha method. Tendon stiffness was determined during isometric plantar flexion by ultrasonography. Active muscle stiffness increased with the exerted torque levels. At 30, 50, 70, and 90% MVC, there were no significant correlations between muscle stiffness using ultrasonography and stiffness of active part (i.e., muscle) by alpha method, although this relationship at 10% MVC was significant ( r = 0.552, P = 0.005). In addition, no correlation was noted in tendon stiffness between the two different methods ( r = 0.226, P = 0.209). The present study demonstrated that ultrasonography could quantified active muscle stiffness in vivo. Furthermore, active muscle stiffness and tendon stiffness using ultrasonography were not related to active (i.e., muscle) or passive (i.e., tendon) stiffness in series elastic component of plantar flexors by alpha method.

Validity of the single limb heel raise test to predict lower extremity disablement in patients with sporadic inclusion body myositis

PURPOSE

To determine the validity of the single limb heel raise (SLHR) test as a potential screening tool to detect lower extremity disability in patients with sporadic inclusion body myositis (sIBM).

METHODS

We compared gait speed and fall history between subjects with sIBM who either could complete one SLHR (SLHR group) or could not complete one SLHR. Discriminative validity was established by comparing between group differences in functional measures based on group assignment. Receiver operating characteristics curve analysis was used to determine the predictive validity of completing one repetition on the SLHR test. Spearman correlations were used to determine the association between gait kinematics and number of repetitions achieved on the SLHR test.

RESULTS

Forty-three subjects (13 females) were studied. The SLHR group (n = 21) showed significantly greater gait speed (p < 0.001) and decreased gait aid use (p < 0.05) compared to the no SLHR group (n = 22). SLHR cut scores of 1, 20, and 22 repetitions maximized positive likelihood ratios (+LR) for the ability to walk at 54.9 (+LR. 2.2), 63.2 (+LR. 9.5), and 73.1 m/min (+LR. 5.0), respectively.

CONCLUSION

The SLHR test demonstrates adequate discriminative and predictive validity as a screening tool for lower extremity disablement in patients with sIBM. Implications for Rehabilitation The SLHR test has adequate reliability and validity to screen for the presence of lower extremity disablement in patients with sIBM. Results of this rapid field test may be used to guide the need for rehabilitation services to mitigate the effects of slow gait speeds in patients with sIBM.

Skeletal muscle fatigue

Skeletal muscle fatigue is defined as the fall of force or power in response to contractile activity. Both the mechanisms of fatigue and the modes used to elicit it vary tremendously. Conceptual and technological advances allow the examination of fatigue from the level of the single molecule to the intact organism. Evaluation of muscle fatigue in a wide range of disease states builds on our understanding of basic function by revealing the sources of dysfunction in response to disease.

Raising the standards of the calf-raise test: a systematic review

The calf-raise test is used by clinicians and researchers in sports medicine to assess properties of the calf muscle-tendon unit. The test generally involves repetitive concentric-eccentric muscle action of the plantar-flexors in unipedal stance and is quantified by the number of raises performed. Although the calf-raise test appears to have acceptable reliability and face validity, and is commonly used for medical assessment and rehabilitation of injuries, no universally acceptable test parameters have been published to date. A systematic review of the existing literature was conducted to investigate the consistency as well as universal acceptance of the evaluation purposes, test parameters, outcome measurements and psychometric properties of the calf-raise test. Nine electronic databases were searched during the period May 30th to September 21st 2008. Forty-nine articles met the inclusion criteria and were quality assessed. Information on study characteristics and calf-raise test parameters, as well as quantitative data, were extracted; tabulated; and statistically analysed. The average quality score of the reviewed articles was 70.4+/-12.2% (range 44-90%). Articles provided various test parameters; however, a consensus was not ascertained. Key testing parameters varied, were often unstated, and few studies reported reliability or validity values, including sensitivity and specificity. No definitive normative values could be established and the utility of the test in subjects with pathologies remained unclear. Although adapted for use in several disciplines and traditionally recommended for clinical assessment, there is no uniform description of the calf-raise test in the literature. Further investigation is recommended to ensure consistent use and interpretation of the test by researchers and clinicians.

Evaluation of lower leg function in patients with Achilles tendinopathy

Achilles tendinopathy is considered to be one of the most common overuse injuries in elite and recreational athletes. However, the effect that the Achilles tendinopathy has on patients' physical performance is still unclear. The purpose of this study was to evaluate if Achilles tendinopathy caused functional deficits on the injured side compared with the non-injured side in patients. A test battery comprised of tests for different aspects of muscle-tendon function of the gastrocnemius, soleus and Achilles tendon complex was developed to evaluate lower leg function. The test battery's test-retest reliability and sensitivity (the percent probability that the tests would demonstrate abnormal lower limb symmetry index in patients) were also evaluated. The test battery consisted of three jump tests, a counter movements jump (CMJ), a drop counter movement jump (drop CMJ) and hopping, and two strength tests, concentric toe-raises, eccentric-concentric toe-raises and toe-raises for endurance. The reliability was evaluated through a test-retest design on 15 healthy subjects. The test battery's sensitivity and possible functional deficits in patients with Achilles tendinopathy were evaluated on 42 patients (19 women and 23 men). An excellent reliability was found between test days 1-2 and 2-3 for all tests (ICC = 0.76-0.94) except for concentric toe-raise, test 2-3, which had fair reliability (ICC = 0.73). The methodological error ranged from 8 to 17%. There were significant differences (P = 0.001-0.049) between the non-injured (or least symptomatic) side and injured (most symptomatic) side for hopping, drop CMJ, concentric and eccentric-concentric toe-raises, and significant differences (P = 0.000-0.012) in the level of pain during CMJ, hopping, and drop CMJ. The sensitivity of the test battery at a 90% capacity was 88. Achilles tendinopathy causes not only pain and symptoms in patients but also apparent impairments in various aspects of lower leg muscle-tendon function as measured with the test battery. This test battery is reliable and able to detect differences in lower leg function between the injured or "most symptomatic" and non-injured or "least symptomatic" side in patients with Achilles tendinopathy. The test battery has higher demand on patients' function compared with each individual test.