Significant functional impairment and disability in individuals with psoriatic arthritis and Achilles tendon pain: a cross-sectional observational study.

The Achilles tendon (AT) insertion is the most common site of enthesitis in psoriatic arthritis (PsA). The structure and function of the AT in PsA, and the prevalence of mid-portion pathology, is unknown. To compare the structure and function of the AT in people with PsA with self-reported AT pain (PsA + AT), PsA without self-reported AT pain (PsA-AT) and healthy controls. A cross-sectional, observational study was conducted. The ATs were assessed by clinical and US examination (B-mode and Power Doppler), performance-based testing (bilateral heel raise test (HRT) and 10 m walk test), and patient-reported outcome measures (PROMs) (including the Victorian Institute of Sport Assessment-Achilles [VISA-A]). Between-group differences were described using descriptive statistics, Chi-squared testing, parametric (1-way ANOVA) and non-parametric (Mann-Whitney or Kruskal-Wallis) testing. 22 PsA (11 per group) and 11 healthy control participants who were comparable in terms of sex, age, and BMI (PsA-AT = longer PsA disease duration) were recruited. VISA-A scores were significantly worse in the PsA + AT group compared to the PsA-AT group and healthy controls (p < 0.001). Inflammatory US features were significantly more prevalent in the PsA + AT group (p < 0.001). Mid-portion AT pathology was observed in the PsA + AT group, irrespective of entheseal disease. Clinical examination alone missed 5/7 cases of 'active' US-confirmed AT enthesitis. AT functional deficits were significant in the PsA + AT group and both PsA groups had lower HRT repetition rates and walked slower compared to healthy controls. Less than 1/3 of the PsA + AT group had received podiatry or physiotherapy care. Significant differences in the structure and function of the AT in PsA were noted. Despite management in line with current guidance, AT pain appears to persist and can result in severe functional impairment.

Reduced Intratendinous Sliding in Achilles Tendinopathy During Active Plantarflexion Regardless of Horizontal Foot Position.

PURPOSE: The Achilles tendon consists of three subtendons with the ability to slide relative to each other. As optimal intratendinous sliding is thought to reduce the overall stress in the tendon, alterations in sliding behavior could potentially play a role in the development of Achilles tendinopathy. The aims of this study were to investigate the difference in intratendinous sliding within the Achilles tendon during isometric contractions between asymptomatic controls and patients with Achilles tendinopathy and the effect of changing the horizontal foot position on intratendinous sliding in both groups. METHODS: Twenty-nine participants (13 Achilles tendinopathy and 16 controls) performed isometric plantarflexion contractions at 60% of their maximal voluntary contraction (MVC), in toes-neutral, and at 30% MVC in toes-neutral, toes-in, and toes-out positions during which ultrasound images were recorded. Intratendinous sliding was estimated as the superficial-to-middle and middle-to-deep relative displacement. RESULTS: Patients with Achilles tendinopathy present lower intratendinous sliding than asymptomatic controls. Regarding the horizontal foot position in both groups, the toes-out foot position resulted in increased sliding compared with both toes-neutral and toes-out foot position. CONCLUSION: We provided evidence that patients with Achilles tendinopathy show lower intratendinous sliding than asymptomatic controls. Since intratendinous sliding is a physiological feature of the Achilles tendon, the external foot position holds promise to increase sliding in patients with Achilles tendinopathy and promote healthy tendon behavior. Future research should investigate if implementing this external foot position in rehabilitation programs stimulates sliding within the Achilles tendon and improves clinical outcome.

Inhibitory kinesiotaping has no effect on post-stroke spasticity: Prospective, randomised, controlled study.

OBJECTIVE: Motor neuron pool activity is high in spasticity. The effect of inhibitory kinesiotaping (KT) on spasticity is unclear. The aim of this study is to investigate the effect of inhibitory KT on spasticity after stroke. METHODS: Fifty stroke patients with ankle plantarflexor spasticity were randomised to intervention (27) and control (23) groups. Inhibitory KT was applied to the triceps surae muscle in the intervention group and sham KT to the Achilles tendon in the control group. Inhibitory and sham KT were applied for 72 h with a combined conventional rehabilitation programme. Spasticity was assessed at baseline and 72 h after KT using three instruments: Modified Ashworth Scale (MAS), Homosynaptic Post-Activation Depression (HPAD) reflecting the level of motor neuron pool activity, and joint torque as a measure of resistance to passive ankle dorsiflexion. RESULTS: The baseline MAS score, HPAD levels and dorsiflexion torque of the two groups were not significantly different. The change in MAS score was -3.7 ± 17.5 (p = 0.180) in the intervention group and 3.6 ± 33.3 (p = 0.655) in the control group. The change in dorsiflexion torque was -0.3 ± 16.1 kg m (p = 0.539) in the intervention group and 8.0 ± 24.1 kg m (p = 0.167) in the control group. The change in mean HPAD was 8.7 ± 34.7 (p = 0.911) in the intervention group and 10.1 ± 41.6 (p = 0.609) in the control group. CONCLUSIONS: The present study showed that inhibitory KT has no antispastic effect in stroke patients.

Efficacy of heel lifts for mid-portion Achilles tendinopathy (the LIFT trial): study protocol for a randomised controlled trial.

BACKGROUND: Mid-portion Achilles tendinopathy is a common condition, characterised by localised Achilles tendon load-related pain and dysfunction. Numerous non-surgical treatments have been proposed for the treatment of this condition, but many of these treatments have a poor or non-existent evidence base. Heel lifts have also been advocated as a treatment for Achilles tendinopathy, but the efficacy and mechanism of action of this intervention is unclear. This proposal describes a randomised controlled trial comparing the effectiveness of heel lifts versus sham heel lifts for reducing pain associated with mid-portion Achilles tendinopathy, with an embedded biomechanical analysis. METHODS: One hundred and eight men and women aged 18 to 65 years with mid-portion Achilles tendinopathy (who satisfy the inclusion and exclusion criteria) will be recruited. Participants will be randomised, using the website Sealed Envelope, to either a control group (sham heel lifts) or an experimental group (heel lifts). Both groups will be provided with education regarding acceptable pain levels to ensure all participants receive some form of treatment. The participants will be instructed to use their allocated intervention for at least 8 h every day for 12 weeks. The primary outcome measure will be pain intensity (numerical rating scale) at its worst over the previous week. The secondary outcome measures will be additional measures of Achilles tendon pain and disability, participant-perceived global ratings of change, function, level of physical activity and health-related quality of life. Data will be collected at baseline and the primary endpoint (week 12). Data will be analysed using the intention-to-treat principle. In addition, the acute kinetic and kinematic effects of the interventions will be examined at baseline in a subpopulation of the participants (n = 40) while walking and running using three-dimensional motion analysis. DISCUSSION: The LIFT trial (efficacy of heeL lIfts For mid-portion Achilles Tendinopathy) will be the first randomised trial to compare the efficacy of heel lifts to a sham intervention in reducing pain and disability in people with Achilles tendinopathy. The biomechanical analysis will provide useful insights into the mechanism of action of heel lifts. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry, ACTRN12623000627651 . Registered 7 June 2023.

Wearing an ultrasound probe during walking does not influence lower limb joint kinematics in adolescents with cerebral palsy and typically developing peers.

BACKGROUND: Enhancing traditional three-dimensional gait analysis with a portable ultrasound device at the lower-limb muscle-tendon level enables direct measurement of muscle and tendon lengths during walking. However, it is important to consider that the size of the ultrasound probe and its attachment on the lower limb may potentially influence gait pattern. RESEARCH QUESTION: What is the effect of wearing an ultrasound probe at the lower limb in adolescents with cerebral palsy and typically developing peers? METHODS: Eleven individuals with cerebral palsy and nine age-matched typically developing peers walking barefoot at their self-selected speed were analyzed. Data collection occurred under three conditions: the reference condition (GAIT), and two conditions involving placement of the ultrasound probe over the distal medial gastrocnemius-Achilles tendon junction (MTJ) and over the medial gastrocnemius mid-belly to capture fascicles (FAS). Data processing included calculating differences between conditions using root mean square error (RMSE) for joint kinematics and comparing them to the overall mean difference. Additionally, Spearman correlations were calculated to examine the relationship between kinematic RMSEs and walking speed. RESULTS: No significant differences in stance phase duration or walking speed were observed among the three conditions. Average RMSEs were below 5° for all parameters and condition comparisons in both groups. In both the TD and CP groups, RMSE values during the swing phase were higher than those during the stance phase for all joints. No significant correlations were found between height or body mass and swing phase RMSEs. In the CP group, there was a significant correlation between joint kinematics RMSEs and differences in walking speed at the hip, knee and ankle joints when comparing the MTJ condition with the GAIT condition. SIGNIFICANCE: This study confirms joint kinematics alterations are smaller than 5° due to wearing to the leg an ultrasound probe during walking.

Are we asking the right questions to people with Achilles tendinopathy? The best questions to distinguish mild versus severe disability to improve your clinical management.

OBJECTIVE: Determine the capacity of individual items on the Tendinopathy Severity Assessment - Achilles (TENDINS-A), Foot and Ankle Outcome Score (FAOS), and Victorian Institute of Sports Assessment - Achilles (VISA-A) to differentiate patients with mild and severe tendon-related disability in order to provide clinicians the best questions when they are consulting patients with Achilles tendinopathy. DESIGN: Cross-sectional. PARTICIPANTS: Seventy participants with Achilles tendinopathy (61.4% mid-portion only, 31.4% insertional only, 7.2% both). OUTCOME MEASURES: The discrimination index was determined for each TENDINS-A, FAOS, and VISA-A item to determine if items could discriminate between mild and severe disability. A Guttman analysis for polytomous items was conducted. RESULTS: All 62 tems from the TENDINS-A, FAOS, and VISA-A were ranked with the best items relating to pain with physical tendon loading, time for pain to settle following aggravating activities and time for the tendon to 'warm-up' following inactivity. CONCLUSIONS: Pain with loading the Achilles tendon, time for pain to settle following aggravating activity, as well as time taken for the tendon symptoms to subside after prolonged sitting or sleeping are the best questions indicative of the severity of disability in patients with Achilles tendinopathy. These questions can assist clinicians with assessing baseline severity and monitoring treatment response.

Four hours of normobaric hypoxia reduces Achilles tendon reflex inhibition.

Acute exposure to hypoxia increases postural sway, but the underlying neurophysiological factors are unclear. Golgi tendon organs (GTOs), located within the musculotendinous junction (MTJ), provide inhibitory signals to plantar flexor muscles that are important for balance control; however, it is uncertain if GTO function is influenced by hypoxia. The aim of this study was to determine how normobaric hypoxia influences lower limb tendon-evoked inhibitory reflexes during upright stance. We hypothesized that tendon-evoked reflex area and duration would decrease during hypoxia, indicating less inhibition of postural muscles compared with normoxia. At baseline (BL; 0.21 fraction of inspired oxygen, FIO2) and at ∼2 (H2) and 4 (H4) h of normobaric hypoxia (0.11 FIO2) in a normobaric hypoxic chamber, 16 healthy participants received electrical musculotendinous stimulation (MTstim) to the MTJ of the left Achilles tendon. The MTstim was delivered as two sets of 50 stimuli while the participant stood on a force plate with their feet together. Tendon-evoked inhibitory reflexes were recorded from the surface electromyogram of the ipsilateral medial gastrocnemius, and center of pressure (CoP) variables were recorded from the force plate. Normobaric hypoxia increased CoP velocity (P ≤ 0.002) but not CoP standard deviation (P ≥ 0.12). Compared with BL, normobaric hypoxia reduced tendon-evoked inhibitory reflex area by 45% at H2 and 53% at H4 (P ≤ 0.002). In contrast, reflex duration was unchanged during hypoxia. The reduced inhibitory feedback from the GTO pathway could likely play a role in the increased postural sway observed during acute exposure to hypoxia.NEW & NOTEWORTHY The Ib pathway arising from the Golgi tendon organ provides inhibitory signals onto motor neuron pools that modifies force and, hence, postural control. Although hypoxia influences standing balance (increases sway), the underlying mechanisms have yet to be unraveled. Our study identified that tendon-evoked inhibition onto a plantar flexor motoneuron pool is reduced by acute exposure to normobaric hypoxia. This reduction of inhibition may contribute to the hypoxia-related increase in postural sway.

Diagnostic value of Achilles tendon shear wave elastography in patients with ankylosing spondylitis: A case-control study.

OBJECTIVES: Ankylosing spondylitis (AS) can cause peripheral arthritis, tendinitis, enthesitis, and axial skeletal involvement. This study aims to determine early tendon damage by shear wave elastography (SWE) for the Achilles tendon in AS patients. METHODS: 48 AS patients and 48 asymptomatic individuals were included in the study. Participants were systematically examined with B-mode, power Doppler, and SWE using a high-resolution linear 6-15 MHz probe. Bilateral Achilles tendon stiffness, thickness, and vascularity were evaluated. Measurements were taken from the middle third of the Achilles tendon in the sagittal plane. Difference between the two groups was evaluated with statistical methods. Receiver operating characteristic analysis was performed to test the diagnostic performance of Achilles tendon stiffness. Additionally, the Spearman correlation test examined the relationship between Achilles tendon stiffness and disease duration. RESULTS: The difference between the two groups regarding Achilles tendon stiffness was statistically significant (p < 0.05). It was observed that Achilles tendon stiffness decreased in the patient group compared with the control group. The diagnostic value of Achilles tendon stiffness measured by SWE was found to be high. A negative correlation was detected between disease duration and tendon stiffness (p < 0.05). CONCLUSION: In patients diagnosed with AS, deterioration in the Achilles tendon structure was observed, and a significant decrease in tendon stiffness compared with the healthy population. It has been determined that these changes in the Achilles tendon are related to the duration of the disease.

Whipping or tearing? The biomechanics of Achilles tendinopathy in rearfoot strike runners.

BACKGROUND: Two biomechanical mechanisms for the development of Achilles tendinopathy in runners have been proposed: A whipping mechanism characterized by prolonged and excessive rearfoot eversion, and a tearing mechanism characterized by high eccentric plantar flexor forces. The purpose of this pilot study was to determine if runners with and without a history of Achilles tendinopathy exhibited gait biomechanics consistent with either of these mechanisms. METHODS: Seven male runners with previous or current Achilles tendinopathy and seven healthy male control runners were evaluated by three-dimensional gait analysis. Peak rearfoot eversion angle, rearfoot eversion excursion, duration of rearfoot eversion, and peak rearfoot inversion angle were compared between groups to evaluate the whipping mechanism of injury. Peak dorsiflexion angle, peak dorsiflexion velocity, and peak ankle power absorption were compared between groups to evaluate the tearing mechanism. Additionally, rearfoot eversion angle and sagittal plane ankle power waveforms were compared between groups using statistical parametric mapping. FINDINGS: There were no differences in any rearfoot eversion, inversion, or dorsiflexion variables or waveforms during running in the Achilles tendinopathy group compared to controls. INTERPRETATION: Rearfoot strike runners with Achilles tendinopathy do not exhibit running biomechanics consistent with either the whipping or tearing mechanisms of injury.

Asymmetric running is associated with pain during outdoor running in individuals with Achilles tendinopathy in the return-to-sport phase.

OBJECTIVES: To determine the relationships between (1) Achilles tendon pain and loading symmetry, and (2) number of running bouts and symptom severity, during two weeks of outdoor running in individuals with Achilles tendinopathy. DESIGN: Prospective, observational study. SETTING: Biomechanics laboratory and outdoors. PARTICIPANTS: Seventeen runners with Achilles tendinopathy in the return-to-sport phase of rehabilitation. MAIN OUTCOME MEASURES: Symptom severity was recorded with the Victorian Institute of Sports Assessment-Achilles (VISA-A) questionnaire. Running bouts and Achilles tendon pain during runs were recorded with daily training logs. Ground contact time was collected during runs with wearable sensors. Linear mixed modeling determined if the relationship between Achilles tendon pain and ground contact time symmetry during running was moderated by consecutive run days. Multiple regression determined the relationship between number of running bouts and change in VISA-A scores over two weeks, adjusted for run distance. RESULTS: Greater ground contact time on the contralateral leg corresponded to increased ipsilateral tendon pain for each consecutive run day (b = -0.028, p < 0.001). Number of running bouts was not associated with 2-week changes in VISA-A scores (p = 0.672). CONCLUSIONS: Pain during running is associated with injured leg off-loading patterns, and this relationship strengthened with greater number of consecutive run days. Number of running bouts was not related to short-term symptom severity.

Progression of partial to complete ruptures of the Achilles tendon during rehabilitation: A study using a finite element model.

Substantial research on complete Achilles tendon ruptures is available, but guidance on partial ruptures is comparatively sparse. Conservative management is considered acceptable in partial tendon ruptures affecting less than 50% of the tendon's width, but supporting experimental evidence is currently lacking. Using a previously validated finite element model of the Achilles tendon, this study aimed to assess whether loading conditions simulating an early functional rehabilitation protocol could elicit progression to a complete rupture in partial ruptures of varying severity. In silico tendon rupture simulations were performed to locate the most likely rupture site for least, moderate, and extreme subtendon twist configurations. These three models were split at the corresponding rupture site and two sets of partial ruptures were created for each, starting from the medial and lateral sides, and ranging from 10% to 50% loss of continuity. Simulations were conducted with material parameters from healthy and tendinopathic tendons. Partial ruptures were considered to progress if the volume of elements showing a maximum principal strain above 10% exceeded 3 mm3. To assess whether the tendinopathic tendons typical geometric characteristics could compensate for the inferior material properties found in tendinopathy, an additional model with increased cross-sectional area in the free tendon region was developed. Progression to complete ruptures occurred even with less than a 50% loss of continuity, regardless of subtendon twisting, and material parameters. The tendinopathic tendon model with increased cross-sectional area showed similar results. These findings suggest the current criteria for surgical treatment of partial ruptures should be reconsidered. Statement of clinical significance: The clinical significance and most appropriate treatment of partial ruptures of the Achilles tendon is unclear. Despite the widespread use of the "50% rule" in treatment decisions of partial tendon ruptures, experimental evidence supporting it is missing. The present study provides new data, from a validated aponeurotic and free Achilles tendon finite element model, showing that partial ruptures may progress to complete ruptures under loading conditions elicited from functional rehabilitation protocols, even for partial ruptures affecting less than 50% of the tendon's width. Under these novel findings, the current criteria for surgical treatment of partial ruptures should be reconsidered.

Medial arch instability/internal foot overload association with non-insertional Achilles tendinopathy and the 'Zone of Conflict Theory'.

BACKGROUND: Non insertional Achilles tendinopathy [AT] is a degenerative condition that is prevalent in runners. 30% have no preceding history and many runners do not develop AT. Overuse, pronation, and compromised blood supply are hypothesised as causal. The exact precipitant is still unknown. The link between medial arch instability and AT has not been made. The purpose of this study was to investigate the association between spring ligament (SL) laxity and first ray (FRI) instability, and the presence of (AT). METHODS: Ethical approval was obtained. Patients were identified from hospital databases for unilateral AT, allowing the opposite unaffected foot to be used as an internal control. SL laxity was measured using the lateral translation score and FRI was measured using a modified digital Klauemeter. Ultrasound was used to assess the tendoachilles [TA] in affected vs unaffected legs. RESULTS: 17 patients were recruited with a mean age of 55.6 and mean body mass index (BMI) of 33.3. The average symptom duration was 3.62 years. There were 12 left feet and 5 right feet. There was no statistical difference in dorsiflexion angles for the TA or the gastrocnemius. All Beighton scores < 5. Lateral translation scores, FRI scores and TA thickness was significantly greater in AT feet [p < 0.05]. More affected feet had Tibialis posterior tendon pain (TP) [p < 0.05]. CONCLUSIONS: Feet with AT exhibit higher lateral translation scores and greater FRI compared to healthy feet, and combined with previous literature evidence, suggests alteration of the subtalar axis alters force moments that may lead to an intrinsic overload of the TA, when the foot enters a "zone of conflict". Medial arch instability, in particular SL laxity and FRI, may contribute to the development of non-insertional AT and treatment of this with early arch support may prevent progressive degeneration.

A comparative biomechanical study of the krackow suture technique with three common percutaneous suture techniques in the treatment of Achilles tendon ruptures.

BACKGROUND: The aim of this study was to compare the biomechanical resistance under tensile forces of the Krackow suture technique with the frequently used Dresden, Carmont & Maffulli, and Ma & Griffiths percutaneous repair techniques in bovine models of Achilles tendon rupture. METHODS: Transverse Achilles tendon rupture models were created from 4 cm proximal of the calcaneal insertion point in a total of 20 bovine Achilles tendon specimens. These were randomly allocated to 4 groups and repaired with configurations appropriate to the Dresden, Carmont & Maffulli, Ma & Griffiths and Krackow techniques. Failure mechanisms were recorded with force values (as Newton units) creating a 5 mm gap and load to failure under tensile loading at a rate of 10 mm/sec in a static testing device. RESULTS: In the Dresden technique group, the force required for a 5 mm gap was mean 41.21 ± 13.19 N and for load to failure, mean 193.83 ± 30.16 N, which were evaluated as statistically significantly higher than in the other techniques (p < 0.05). The lowest values were determined in the Ma & Griffiths technique group (5 mm gap: 11.06 ± 8.12 N, load to failure: 97.73 ± 29.60 N) but these were not significantly lower than the values in the Krackow and Carmont & Maffulli technique groups (p > 0.05). CONCLUSION: The results of this study showed that the Dresden technique was biomechanically superior against tensile forces compared to the Krackow technique, and the other frequently used percutaneous techniques of Carmont & Maffulli and Ma & Griffiths.

Evaluation of tendon and ligament microstructure and mechanical properties in a canine model of mucopolysaccharidosis I.

Mucopolysaccharidosis (MPS) I is a lysosomal storage disorder characterized by deficient alpha-l-iduronidase activity, leading to abnormal accumulation of glycosaminoglycans (GAGs) in cells and tissues. Synovial joint disease is prevalent and significantly reduces patient quality of life. There is a strong clinical need for improved treatment approaches that specifically target joint tissues; however, their development is hampered by poor understanding of underlying disease pathophysiology, including how pathological changes to component tissues contribute to overall joint dysfunction. Ligaments and tendons, in particular, have received very little attention, despite the critical roles of these tissues in joint stability and biomechanical function. The goal of this study was to leverage the naturally canine model to undertake functional and structural assessments of the anterior (cranial) cruciate ligament (CCL) and Achilles tendon in MPS I. Tissues were obtained postmortem from 12-month-old MPS I and control dogs and tested to failure in uniaxial tension. Both CCLs and Achilles tendons from MPS I animals exhibited significantly lower stiffness and failure properties compared to those from healthy controls. Histological examination revealed multiple pathological abnormalities, including collagen fiber disorganization, increased cellularity and vascularity, and elevated GAG content in both tissues. Clinically, animals exhibited mobility deficits, including abnormal gait, which was associated with hyperextensibility of the stifle and hock joints. These findings demonstrate that pathological changes to both ligaments and tendons contribute to abnormal joint function in MPS I, and suggest that effective clinical management of joint disease in patients should incorporate treatments targeting these tissues.

Double-Row Achilles Insertional Repair With Rip-Stop Increases Construct Strength Compared to Traditional Techniques: A Biomechanical Study.

BACKGROUND: Although double-row suture-anchored (DRSA) techniques for Achilles insertional tendinosis has proven successful, a reoccurring failure mode not yet addressed is suture tearing through the tendon. This study aims to address suture tearing by incorporating a rip-stop element. Authors hypothesized that the Rip-Stop group would demonstrate increased strength compared with more traditional techniques. METHODS: 12 paired cadaveric feet were used in this study (n = 24). One sample from each pair was assigned to receive the standard double-row (SDR) Achilles repair with 4.75-mm knotless anchors (n = 12). The control's matched sides were divided between 2 DRSA bridge groups: modified double-row (MDR) bridge with 3.9-mm anchors or rip-stop double-row (RS-DR) bridge repair with soft proximal anchors and 3.9-mm anchored distal row. In neutral position, specimens underwent 1000 cycles (20-100 N) followed by load to failure. Displacements, stiffness, ultimate load, and failure mode were recorded. RESULTS: RS-DR had the lowest initial displacement values followed by SDR and MDR (1.3 ± 0.4, 2.7 ± 1.4, and 3.2 ± 1.3 mm, respectively). Significance was detected when comparing initial displacement of RS-DR to MDR (P = .038). Cyclic displacement was lowest for RS-DR, followed by MDR and SDR (1.6 ± 0.9, 2.2 ± 1.1, and 4.5 ± 3.2 mm, respectively). Cyclic stiffness was similar for RS-DR and MDR (89.1 ± 24.6 and 81.9 ± 5.6 N/mm, respectively). RS-DR ultimate load (1116.8 ± 405.7 N) was statistically greater than SDR (465.6 ± 352.7, P = .003). CONCLUSION: RS-DR-repaired specimens demonstrated a decrease in displacement values and increased ultimate load and stiffness when compared to other groups. Results of this cadaveric model suggest that the addition of a rip-stop to DRSA Achilles repair is more impactful than anchor size. Limitations include that this was a time-zero biomechanical study, which cannot simulate the performance of the repairs during postoperative healing and recovery. CLINICAL RELEVANCE: A rip-stop technique for Achilles repair effectively improves dynamic mechanical characteristics and may mitigate suture tearing through tendon in a patient cohort.

Can the Achilles tendon regenerate completely following percutaneous tenotomy in older children with clubfoot?

PURPOSE: The aims of the study were to document the outcomes of percutaneous Achilles tenotomy (pAT) performed in older children with clubfoot, by assessing the clinical, functional and ultrasonographic evidence of Achilles tendon regeneration. METHODS: A retrospective case series of older children with clubfoot treated between August 2011 and July 2020 was studied. Clinical assessment of ankle range of motion and calf strength, functional assessment of triceps surae muscle endurance by single leg heel-rise test, and ultrasonographic assessment of Achilles tendon echotexture and dimensions to assess tendon regeneration were performed. RESULTS: Percutaneous Achilles tenotomy was performed on 31 children (48 clubfeet) at a mean age of 5.24 ± 2.14 years (1-10.2 years). At a mean follow-up of 4.86 ± 1.97 years, all children demonstrated normal calf strength with mean dorsiflexion range of 13.64° (0-25°) and mean plantarflexion range of 37.95° (10-40°). The heel-rise endurance test was completed by 27 children with mean 25.85 heel rises/minute (range 17-30) and mean height of heel rise of 6.29 cm (range 4-10 cm). Normal fibrillar tendinous echotexture with homogenous echogenicity was seen on ultrasonography in 41 feet (85.4%) with mean tendon width of 9.7 mm (3.3-16 mm) and thickness of 5.1 mm (1.8-15 mm), comparable with unaffected feet. CONCLUSIONS: Clinical, functional and ultrasonographic parameters unequivocally demonstrate complete regeneration of the Achilles tendon, when pAT is performed in older children with delayed-presenting idiopathic clubfoot treated using Ponseti principles.

Human Achilles tendon mechanical behavior is more strongly related to collagen disorganization than advanced glycation end-products content.

Diabetes is associated with impaired tendon homeostasis and subsequent tendon dysfunction, but the mechanisms underlying these associations is unclear. Advanced glycation end-products (AGEs) accumulate with diabetes and have been suggested to alter tendon function. In vivo imaging in humans has suggested collagen disorganization is more frequent in individuals with diabetes, which could also impair tendon mechanical function. The purpose of this study was to examine relationships between tendon tensile mechanics in human Achilles tendon with accumulation of advanced glycation end-products and collagen disorganization. Achilles tendon specimens (n = 16) were collected from individuals undergoing lower extremity amputation or from autopsy. Tendons were tensile tested with simultaneous quantitative polarized light imaging to assess collagen organization, after which AGEs content was assessed using a fluorescence assay. Moderate to strong relationships were observed between measures of collagen organization and tendon tensile mechanics (range of correlation coefficients: 0.570-0.727), whereas no statistically significant relationships were observed between AGEs content and mechanical parameters (range of correlation coefficients: 0.020-0.210). Results suggest that the relationship between AGEs content and tendon tensile mechanics may be masked by multifactorial collagen disorganization at larger length scales (i.e., the fascicle level).

Achilles Tendinopathy, A Brief Review and Update of Current Literature.

ABSTRACT: Chronic pain in the Achilles tendon is a common problem in both athletes and nonathletes alike. The etiology for the development of Achilles tendinopathy has not been fully elucidated, and there remains multiple theories to explain the pain and dysfunction accompanying this condition. The diagnosis of Achilles tendon problems continues to rely on the clinical history and physical examination. The optimal management of pain, restoration of function, and return-to-sports participation with Achilles tendinopathy are evolving because of the advancement in technologies and research regarding its pathophysiology. This article aims to provide a brief review of the relevant anatomy, differential diagnosis, imaging findings, and an update of the literature on conservative and minimally invasive managements of chronic Achilles tendinopathy.

Grafting of iPS cell-derived tenocytes promotes motor function recovery after Achilles tendon rupture.

Tendon self-renewal is a rare occurrence because of the poor vascularization of this tissue; therefore, reconstructive surgery using autologous tendon is often performed in severe injury cases. However, the post-surgery re-injury rate is relatively high, and the collection of autologous tendons leads to muscle weakness, resulting in prolonged rehabilitation. Here, we introduce an induced pluripotent stem cell (iPSC)-based technology to develop a therapeutic option for tendon injury. First, we derived tenocytes from human iPSCs by recapitulating the normal progression of step-wise narrowing fate decisions in vertebrate embryos. We used single-cell RNA sequencing to analyze the developmental trajectory of iPSC-derived tenocytes. We demonstrated that iPSC-tenocyte grafting contributed to motor function recovery after Achilles tendon injury in rats via engraftment and paracrine effects. The biomechanical strength of regenerated tendons was comparable to that of healthy tendons. We suggest that iPSC-tenocytes will provide a therapeutic option for tendon injury.

Assessment of Functional Conservative Treatment of Acute Complete Achilles Tendon Rupture.

BACKGROUND: In recent years, treatment for Achilles tendon rupture (ATR) went through radical changes: from the conservative non-weight bearing approach to a functional protocol. This functional protocol allows complete weight bearing after only 2 weeks by placing the foot in a plastic boot in tapered down equines and using interchangeable wedges under the heel. This change of approach has dramatically lowered the rate of re-rupture. OBJECTIVES: To describe our preliminary results with this functional protocol and to assess outcome measures in the functional conservative treatment. METHODS: The study comprised 15 people who were evaluated clinically and by sonograph. We measured calf circumference, ankle joint range of motion (ROM), and single-leg heel-rise test (SLHRT). In addition, standard scoring methods (Achilles Tendon Rupture Score and Physical Activity Scale) were examined. RESULTS: In our cohort 14 people successfully gained SLHRT. The mean Achilles Tendon Rupture Score functional questionnaire and Physical Activity Scale physical activity questionnaire score was 85.6 of 100, and 4.7 of 6, respectively. There were no significant differences in ankle ROM compared to the uninjured limb. There was statistically significant reduction in the calf circumference and soleus muscle thickness sonographically. CONCLUSIONS: It seems that the conservative functional treatment of ATR demonstrates good functional outcomes, with the patients returning to close to normal activity, although noted muscle wasting and weakness. This protocol presents a true alternative to surgery and should be considered for most non-insertional Achilles tendon tears.