Efficacy of heel lifts for lower limb musculoskeletal conditions: A systematic review.

INTRODUCTION: The objective of this systematic review is to determine the benefits and harms of heel lifts to any comparator for lower limb musculoskeletal conditions. METHODS: Ovid MEDLINE, Ovid AMED, Ovid EMCARE, CINAHL Plus and SPORTDiscus were searched from inception to the end of May 2024. Randomised, quasi-randomised or non-randomised trials comparing heel lifts to any other intervention or no-treatment were eligible for inclusion. Data was extracted for the outcomes of pain, disability/function, participation, participant rating of overall condition, quality of life, composite measures and adverse events. Two authors independently assessed risk of bias and certainty of evidence using the GRADE approach at the primary time point 12 weeks (or next closest). RESULTS: Eight trials (n = 903), investigating mid-portion Achilles tendinopathy, calcaneal apophysitis and plantar heel pain were included. Heel lifts were compared to exercise, ultrasound, cryotherapy orthotics, stretching, footwear, activity modification, felt pads and analgesic medication. No outcome was at low risk of bias and few effects (2 out of 47) were clinically important. Low-certainty evidence (1 trial, n = 199) indicates improved pain relief (55.7 points [95% CI: 50.3-61.1], on a 100 mm visual analogue scale) with custom orthotics compared to heel lifts at 12 weeks for calcaneal apophysitis. Very low-certainty evidence (1 trial, n = 62) indicates improved pain and function with heel lifts over indomethacin (35.5 points [95% CI: 21.1-49.9], Foot Function Index) at 12 months for plantar heel pain. CONCLUSIONS: Few trials have assessed the benefits and harms of heel lifts for lower limb musculoskeletal conditions. Only two outcomes out of 47 showed clinically meaningful between group differences. However, due to very low to low certainty evidence we are unable to be confident in the results and the true effect may be substantially different. REGISTRATION: PROSPERO registration number CRD42022309644.

The relationship between psychological, cognitive, and contextual factors and rehabilitation outcomes in Achilles tendinopathy: A prospective feasibility cohort study.

OBJECTIVES: This study aimed to investigate the feasibility of conducting a full-scale study investigating the influence of patient-related factors on rehabilitation outcomes in Achilles tendinopathy (AT). A secondary aim was to investigate preliminary relationships between patient-related factors and clinical outcomes at 12- and 26- weeks. DESIGN: feasibility cohort. SETTING: Australian healthcare settings. METHODS: Participants with AT receiving physiotherapy in Australia were recruited via treating physiotherapists and online. Data were collected online at baseline, 12- and 26-weeks. Progression criteria for a full-scale study were recruitment rate of ≥10 per month, conversion rate ≥20%, and response rate to questionnaires ≥80%. The relationship between patient-related factors and clinical outcomes was investigated using Spearman's rho correlation coefficient. RESULTS: The average recruitment rate was 5/month, conversion rate was 97%, and response rate to questionnaires was ≥97% at all timepoints. There was a fair to moderate correlation (rho = 0.225 to 0.683) between patient-related factors and clinical outcomes at the 12-week, but no to weak correlation at the 26-week (rho = 0.002 to 0.284). CONCLUSIONS: Feasibility outcomes suggest a future full-scale cohort study is feasible with the caveat of utilizing strategies to improve recruitment rate. Preliminary bivariate correlations at 12-weeks warrant further investigations in larger studies.

The acute effects of higher versus lower load duration and intensity on morphological and mechanical properties of the healthy Achilles tendon: a randomized crossover trial.

The Achilles tendon (AT) exhibits volume changes related to fluid flow under acute load which may be linked to changes in stiffness. Fluid flow provides a mechanical signal for cellular activity and may be one mechanism that facilitates tendon adaptation. This study aimed to investigate whether isometric intervention involving a high level of load duration and intensity could maximize the immediate reduction in AT volume and stiffness compared with interventions involving a lower level of load duration and intensity. Sixteen healthy participants (12 males, 4 females; age 24.4±9.4 years, body mass 70.9±16.1 kg, height 1.7±0.1 m) performed three isometric interventions of varying levels of load duration (2 s and 8 s) and intensity (35% and 75% maximal voluntary isometric contraction) over a 3 week period. Freehand 3D ultrasound was used to measure free AT volume (at rest) and length (at 35%, 55% and 75% of maximum plantarflexion force) pre- and post-interventions. The slope of the force-elongation curve over these force levels represented individual stiffness (N mm-1). Large reductions in free AT volume and stiffness resulted in response to long-duration high-intensity loading whilst less reduction was produced with a lower load intensity. In contrast, no change in free AT volume and a small increase in AT stiffness occurred with lower load duration. These findings suggest that the applied load on the AT must be heavy and sustained for a long duration to maximize immediate volume reduction, which might be an acute response that enables optimal long-term tendon adaptation via mechanotransduction pathways.

Immediate and long-term effects of mechanical loading on Achilles tendon volume: A systematic review and meta-analysis.

The Achilles tendon (AT) may experience changes in dimensions related to fluid flow under load. The extent to which fluid flow involves redistribution within or flow out of the tendon is not known and could be determined by investigating volume changes. This study aimed to synthesize data on immediate and long-term effects of loading on tendon volume among people with a healthy AT and midportion Achilles tendinopathy (MAT). A secondary aim was to synthesise data from the included studies investigating parallel change in cross-sectional area and length. Systematic electronic search was performed in MEDLINE, EMBASE, CINAHL, AMED, and Scopus from inception until May 2020. Standardized mean differences (SMDs) were calculated for intervention-induced changes from baseline for all outcomes. Methodological quality was assessed using modified version of Newcastle Ottawa Scale (NOS). Twelve studies were included in meta-analysis. For healthy AT, there were negligible to small changes in volume following cross-country running (-0.33 [95% CI = -1.11 to 0.45] (P = 0.41)) and isometric exercise (0.01 [95% CI = -0.54 to 0.55] (P = 0.98)) and a large increase at the short-term with 12-week isometric protocol (0.88 [95% CI = -0.10 to1.86] (P = 0.08)). For MAT, there was an immediate large reduction in volume with isometric exercise (-1.24 [95% CI = -1.93 to -0.55] (P = 0.0004)), small increase with eccentric exercise (0.41 [95% CI = -0.18 to 1.01](P = 0.18)) and small reduction at the short-term with long-term interventions (-0.46 [95% CI = -0.87 to -0.05] (P = 0.03)). This meta-analysis suggests that healthy AT remain isovolumetric with acute interventions while MAT exhibit immediate and short-term volume reductions in response to different interventions.

Reliability of Human Achilles Tendon Stiffness Measures Using Freehand 3-D Ultrasound.

Achilles tendon (AT) stiffness is an important property of both human locomotor performance and injury mechanics. Freehand 3-D ultrasound (3-DUS) is a promising method for measuring stiffness of the Achilles tendon, particularly the free AT (2-6 cm proximal to calcaneus), which is commonly injured. The aim of this study was to investigate the test-retest reliability of freehand 3-DUS in measuring free AT stiffness in humans. The free Achilles tendon length of healthy participants (n = 10) was scanned on the same day on two consecutive occasions (1 h apart) during rest and isometric plantar flexion contractions at 20%, 40% and 60% of maximum force. The slope of the force-elongation curve over these force levels represented individual stiffness (N/mm). Relative reliability was assessed using the intra-class correlation coefficient (ICC), and absolute reliability was estimated with the standard error of measurement (SEM) and smallest detectable change. Systematic bias in stiffness measures was explored by comparing test and retest distributions and Bland-Altman plots. The test-retest reliability of free AT stiffness measured using freehand 3-DUS was excellent [ICC = 0.994, 95% confidence interval [CI]: 0.978-0.999)]. The mean stiffness values at test (361.83 N/mm [170.77]) and retest (364.98 N/mm [168.57]) did not significantly differ (p = 0.72), and the smallest detectable change was 52.14 N/mm. The Bland-Altman plot indicated the absence of systematic bias (95% CI: -22.18 to 15.88). Freehand 3-DUS provides reliable and precise measures of tendon stiffness and can be used to detect small changes in free AT stiffness in response to load or tendon pathology.