Tendon Elongation Research Articles

Effect of Platelet-Rich Plasma on Nonsurgically Treated Acute Achilles Tendon Ruptures: A Randomized, Double-Blinded Prospective Study

Background: An acute Achilles tendon rupture (ATR) is a long-lasting and devastating injury. Possible biological augmentation to promote and strengthen tendon healing after an ATR would be desirable. Purpose: To determine whether the application of a platelet-rich plasma (PRP) injection in nonsurgically treated ATRs may promote healing and thereby improve functional outcomes. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: A total of 40 men (aged 18-60 years) with an ATR incurred within 72 hours were included, and 38 were followed for 12 months. All patients were treated with an orthosis with 3 wedges for 8 weeks; full weightbearing from day 1 was allowed, combined with either 4 PRP or 4 placebo injections (a few drops of saline, <0.5 mL, under the skin) 14 days apart. All patients received the same instructions on an exercise program starting from week 9. Outcomes included the self-reported Achilles tendon Total Rupture Score (ATRS) as well as heel-rise work, heel-rise height, tendon elongation, calf circumference, and ankle dorsiflexion range of motion. Results: The mean ATRS score improved in both groups at all time points (P < .001), but there was no difference between the groups at any time points (12 months: 90.1 points in PRP group and 88.8 points in placebo group). No differences in all functional outcomes at any time points were seen between the groups. At 12 months, the injured leg did not reach normal functional values compared with the uninjured leg. Conclusion: The application of PRP in nonsurgically treated ATRs did not appear to show any superior clinical and functional improvement. Registration: NCT02417922 (ClinicalTrials.gov identifier)

The strengths of one-, two-, and three-weave Pulvertaft tendon repairs.

We tested the tensile strength of the proximal juncture of tendon grafts with Pulvertaft tendon repairs in 18 cadaveric digital flexor tendons. These tendons were divided into three groups of six: single, two, or three weaves. Each of the interlacing weaves was secured with eight anchoring sutures. The specimens were loaded in a biomechanical tester until failure. The ultimate tensile strength did not show any significant differences across all three groups with statistical power of 0.77. The mean tendon elongation before repair failure showed significant difference at 10 mm (standard deviation (SD) 2), 16 mm (SD 3), and 15 mm (SD 3), respectively. All specimens failed by intra-tendinous pull-out of the weaves. We conclude that the two-weave Pulvertaft construct demonstrated comparable tensile strength to three weaves and tendon elongation was similar when two or three weaves were used.

Individualized treatment for acute Achilles tendon rupture based on the Copenhagen Achilles Rupture Treatment Algorithm (CARTA): a study protocol for a multicenter randomized controlled trial

BackgroundAn individualized treatment algorithm (Copenhagen Achilles Rupture Treatment Algorithm (CARTA)) based on the ultrasonographic appearance of an acute Achilles tendon rupture has been developed aiming to select the correct patients for operative and non-operative treatment. The objective of this study is to investigate if this individualized treatment algorithm gives a better functional outcome than treating all patients either operatively or non-operatively per default.Methods/designThis study is conducted as a multicenter, three-armed randomized controlled trial. Participants are included from four hospitals in Denmark and randomized 1:1:1 to one of three parallel groups: 1) Intervention group—participants are treated according to an individualized treatment algorithm; 2) Control group A—participants are treated non-operatively; 3) Control group B—participants are treated operatively. The individualized treatment algorithm for the intervention group is based on an ultrasonographic examination; tendon overlap and elongation below 7% is to be treated non-operatively, while no tendon overlap and/or elongation above 7% will be treated operatively. Over a period of 3 years, 300 participants will be included. The primary outcome is the heel-rise work test at 12 months post-injury. Secondary outcomes are tendon elongation, the Achilles tendon Total Rupture Score (ATRS), the rate of re-ruptures, and other complications. The primary analysis will be conducted as an intention-to-treat analysis.DiscussionThis trial will indicate if treatment of acute Achilles tendon rupture can be individualized based on elongation and tendon overlap. It is hypothesized that different patients will benefit from different treatments instead of offering all the same treatment.Trial registrationClinicalTrials.gov, NCT03525964. Registered 16 May 2018.

Achilles tendon elongation after acute rupture: is it a problem? A systematic review.

Rupture of the Achilles tendon (AT) is a common injury. Strength deficits may persist over the long term, possibly owing to elongation of the tendon or inferior mechanical properties. This study aimed to provide a systematic review of the literature on the prevalence and consequences of tendon elongation in patients after acute AT rupture treatment. It was hypothesized that an elongated tendon would be associated with a worse clinical outcome. The databases for MEDLINE, CENTRAL and Web of Science were searched. Clinical studies related to AT rupture reporting tendon elongation and clinical or functional outcomes, with a minimum follow-up of 6months, were eligible for inclusion. Only studies testing for statistical correlations (SCs) between AT elongation and other outcomes were eligible, with the exception of biomechanical studies in which statistically significant AT elongation was found to be a generalized finding in the study group. For these studies to be eligible, the study group had to be compared with a healthy control group, or the injured limb compared with the uninjured limb, regarding biomechanical parameters. Twenty-eight papers were selected for inclusion. Mean AT elongation measured with imaging techniques ranged from 0.15 to 3.1cm (n = 17). Ten studies investigated SCs with Patient Reported Outcome Measures (PROMs), in which two found SCs with tendon elongation. Five studies reported strength and power evaluations and their correlation with AT elongation, with two having found SCs between decreased strength and tendon elongation. In ten studies reporting data on biomechanical tests, nine found influence of tendon elongation. In this group, four out of five studies found SCs with biomechanical parameters. Fair evidence of the influence of tendon elongation in biomechanical parameters was found. In a general population, evidence of a detrimental effect of tendon elongation on PROMs or functional strength at follow-up was not found in this review. Level IV.

Histological Changes in Tendon Elongation with Bovine Pericardium.

Histological Changes in Tendon Elongation with Bovine Pericardium.

Comparison of Tendon Lengthening With Traditional Versus Accelerated Rehabilitation After Achilles Tendon Repair: A Prospective Randomized Controlled Trial

Background: Early weightbearing protocols after Achilles tendon repair promote mobilization, yet little is known about their effect on tendon lengthening. Purpose: To evaluate tendon lengthening after Achilles tendon repair with accelerated rehabilitation. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Patients undergoing primary repair for acute Achilles tendon ruptures consented to have tantalum beads placed within the tendon. Patients were randomized into either a traditional (weightbearing at 6 weeks) or accelerated (graduated weightbearing at 2 weeks) rehabilitation group. The primary outcome of the study was postoperative tendon elongation as measured by radiostereometric beads. Secondary outcomes included Achilles Tendon Total Rupture Score (ATRS) and Patient-Reported Outcomes Measurement Information System Pain Interference Short Form (PROMIS PI-SF) score. Results: All 18 patients included in the final analysis were found to have significant tendon lengthening after surgery, with a mean lengthening of 15.9 mm. No significant differences were found in overall lengthening between the traditional and accelerated rehabilitation groups (15.3 ± 4.5 vs 16.4 ± 4.7 mm, respectively; P = .33) at final follow-up. The repair site in each group was found to lengthen more than the intratendinous site (traditional group, 13.2 vs 2.1 mm; accelerated group, 16.8 vs −0.4 mm); however, no difference in lengthening was seen between groups (P = .82 and P = .31, respectively). The greatest amount of lengthening occurred between 2 and 6 weeks, and the least amount of lengthening occurred between 6 and 12 weeks, with no difference between the traditional and accelerated groups at these time points (P = .84 and P = .38, respectively). No differences were noted in ankle range of motion (dorsiflexion, P = .16; plantarflexion, P = .08) or outcome scores (ATRS, P = .56; PROMIS PI-SF, P = .54). Conclusion: This study’s findings demonstrate that all patients undergoing operative repair of Achilles tendon ruptures had lengthening after surgery. No difference was found in tendon lengthening (repair site or intratendinous) at any time point between patients undergoing traditional versus accelerated rehabilitation postoperatively. The greatest amount of lengthening was found to occur between 2 and 6 weeks postoperatively, and tendon lengthening decreased significantly after 6 weeks. Registration: NCT04050748 (ClinicalTrials.gov identifier).

Age and Tightness of Repair Are Predictors of Heel-Rise Height After Achilles Tendon Rupture.

Background:Achilles tendon rupture leads to weakness of ankle plantarflexion. Treatment of Achilles tendon rupture should aim to restore function while minimizing weakness and complications of management.Purpose:To determine the influence of factors (age, sex, body mass index [BMI], weight, time from injury to operative repair, and tightness of repair) in the initial surgical management of patients after an acute Achilles tendon rupture on 12-month functional outcome assessment after percutaneous and minimally invasive repair.Study Design:Cohort study; Level of evidence, 3.Methods:From May 2012 to January 2018, patients sustaining an Achilles tendon rupture receiving operative repair were prospectively evaluated. Tightness of repair was quantified using the intraoperative Achilles tendon resting angle (ATRA). Heel-rise height index (HRHI) was used as the primary 12-month outcome variable. Secondary outcome measures included Achilles tendon total rupture score (ATRS) and Tegner score. Stepwise multiple regression was used to create a model to predict 12-month HRHI.Results:A total of 122 patients met the inclusion criteria for data analysis (mean ± SD age, 44.1 ± 10.8 years; 78% male; mean ± SD BMI, 28.1 ± 4.3 kg/m2). The elapsed time to surgery was 6.5 ± 4.0 days. At 12-month follow-up, patients had an HRHI of 82% ± 16% and performed 82% ± 17% of repetitions compared with the noninjured side. Participants had a mean ATRS of 87 ± 15 and a median Tegner score of 5 (range, 1-9), with a reduction in Tegner score of 2 from preinjury levels. The relative ATRA at 12 months was –4.8° ± 3.9°. Multiple regression identified younger age (B = ±0.006; P < .001) and greater intraoperative ATRA (B = 0.005; P = .053) as predictors of more symmetrical 12-month HRHI (R 2 = 0.19; P < .001; n = 120).Conclusion:Age was found to be the strongest predictor of outcome after Achilles tendon rupture. The most important modifiable risk factor was the tightness of repair. It is recommended that repair be performed as tight as possible to optimize heel-rise height 1 year after Achilles tendon rupture and possibly to reduce tendon elongation.

Lateral Rectus Muscle Tendon Elongation

Lateral Rectus Muscle Tendon Elongation

Interfibrillar shear behavior is altered in aging tendon fascicles.

Tendon elongation involves both stretching and sliding between adjacent fascicles and fibers. Hence, age-related changes in tendon matrix properties may alter sliding behavior and thereby affect injury thresholds. The objective of this study was to investigate the effects of age on interfibrillar shear behavior in partial cut tendon fascicles. Cine microscopic imaging was used to track deformation patterns of intact and partial cut fascicles from mature (9months, n = 10) and aged (32months, n = 10) rat tail tendons. Finite element (FE) models coupled with experimental data provided insight into age-related changes in tissue constitutive properties that could give rise to age-dependent behavior. Intact fascicles from aged tendons exhibited a 28% lower linear region modulus and reduced toe region when compared to fascicles from mature tendons. Partial cut tendon fascicles consistently exhibited a shearing plane that extended longitudinally from the tip of the cut. Both mature and aged fascicles exhibited distinct failure that was observable in differential displacement across the shearing plane. However, aged fascicles exhibited 11-20% higher grip-to-grip strain at failure and tended to exhibit more variable and greater differential displacement at failure, when compared to mature fascicles. FE models suggest that this age-related change in shear behavior arises from a reduction in interfibrillar shear modulus with age. These data suggest that aging alters interfibrillar failure mechanisms and hence may contribute to the increased propensity for injury that is commonly seen in older tendons.

Impact of seated and standing positions on triceps surae muscle activation in unilateral Achilles tendon rupture.

Heel-rises are commonly used in the rehabilitation of individuals following Achilles tendon rupture, however, the impact of tendon elongation on triceps surae activation in seated versus standing positions has not been investigated. The purpose of this study was to investigate changes in triceps surae activation during seated compared to standing heel-rises in individuals with Achilles tendon rupture and its relationship to tendon elongation. Ten individuals with a history of Achilles tendon rupture were included in this study. Muscle activity using electromyography was examined during a heel-rise task in seated (unilateral) and standing (bilateral) positions. Soleus activity was not significantly different between sitting and standing on both the ruptured and uninjured side. On the ruptured, side there were no differences in medial or lateral gastrocnemius activity between sitting and standing; however, on the uninjured side medial and lateral gastrocnemius activity was lower in sitting compared to standing. The results of this study suggest that neuromuscular changes in triceps surae activation occur following Achilles tendon rupture. The seated heel-rise position can be used to strengthen all muscles of the triceps surae and is useful when the patient is unable to perform a standing heel-rise.

Electromyographic Evidence of Excessive Achilles Tendon Elongation During Isometric Contractions After Achilles Tendon Repair.

Background:Weakness in end-range plantarflexion has been demonstrated after Achilles tendon repair and may be because of excessive tendon elongation. The mean frequency (MNF) of surface electromyogram (EMG) data during isometric maximum voluntary contraction (MVC) increases with muscle fiber shortening.Hypothesis:During isometric plantarflexion, MNF during MVCs will be higher on the involved side compared with the uninvolved side after Achilles tendon repair because of excessive tendon elongation and greater muscle fiber shortening.Study Design:Case series; Level of evidence, 4.Methods:Isometric plantarflexion MVC torque was measured at 20° and 10° dorsiflexion, neutral, and 10° and 20° plantarflexion in 17 patients (15 men, 2 women; mean age, 39 ± 9 years) at a mean 43 ± 26 months after surgery. Surface EMG signals were recorded during strength tests. MNF was calculated from fast Fourier transforms of medial gastrocnemius (MG), lateral gastrocnemius (LG), and soleus (SOL) EMG signals.Results:Patients had marked weakness on the involved side versus the uninvolved side in 20° plantarflexion (deficit, 28% ± 18%; P < .001) but no significant weakness in 20° dorsiflexion (deficit, 8% ± 15%; P = .195). MNF increased when moving from dorsiflexion to plantarflexion (P < .001), but overall, it was not different between the involved and uninvolved sides (P = .195). However, differences in MNF between the involved and uninvolved sides were apparent in patients with marked weakness. At 10° plantarflexion, 8 of 17 patients had marked weakness (>20% deficit). MNF at 10° plantarflexion was significantly higher on the involved side versus the uninvolved side in patients with weakness, but this was not apparent in patients with no weakness (side by group, P = .012). Mean MNF at 10° plantarflexion across the 3 muscles was 13% higher on the involved side versus the uninvolved side in patients with weakness (P = .012) versus 3% lower in patients with no weakness (P = .522).Conclusion:Higher MNF on the involved side versus the uninvolved side in patients with significant plantarflexion weakness is consistent with greater muscle fiber shortening. This indicates that weakness was primarily because of excessive lengthening of the repaired Achilles tendon. If weakness was simply because of atrophy, a lower MNF would have been expected and patients would have had weakness throughout the range of motion. Surgical and rehabilitative strategies are needed to prevent excessive tendon elongation and weakness in end-range plantarflexion after Achilles repair.

Minimally invasive reconstruction technique for chronic Achilles tendon tears allows rapid return to walking and leads to good functional recovery

PurposeChronic Achilles tendon tears, including chronic ruptures with end gap over 6 cm making end-to-end suturing impossible, can be treated with autologous hamstring graft reconstruction. The primary goal of this study was to present the biomechanical and long-term clinical results of recently developed minimally invasive Achilles tendon reconstruction technique.MethodsMinimally invasive Achilles tendon reconstruction was applied to 8 foot and ankle cadaveric specimens as well as 18 patients with chronic Achilles tendon tears. Repaired cadavers were subjected to the biomechanical testing using a cyclic loading protocol. Patients with reconstructed Achilles tendon were subjected to the clinical, functional and isokinetic tests at 12 months after the treatment.ResultsAll of tested Achilles cadaveric specimens survived 2 loading blocks (250 cycles of 10–100 N load followed by additional 250 cycles of 10–200 N load). With three specimens, it was possible to perform the third cyclic loading block with 20-300 N load and two specimens survived the fourth block with 20–400 N load. Therefore, a mean number of 838 cycles (±178) within the range of 509–1000 was recorded. Two specimens which survived all 1000 cycles were pulled to failure at 25 mm/s rate. The results obtained in the load to failure testing were as follows: 398 N and 608 N of maximum load. The results of functional heel rise endurance test and single leg hop for distance test indicated a decrease in the endurance and strength of the injured limb. However, the results of the weight-bearing lunge tests indicated no tendency for elongation of the Achilles tendon. A comparative analysis of the isokinetic test results for the non-injured and injured limb was revealed no statistically significant differences for every isokinetic test (n. s.), with significant difference for isometric strength parameters (p = 0.0006).ConclusionsThe results of the biomechanical tests as well as 1-year extensive functional, clinical and isokinetic results of the minimally invasive technique for chronic Achilles tendon tears are encouraging. Patients returned to their normal physical activity, including sport pre-injury level in most cases.Level of evidenceIII

Relationship of Postoperative Achilles Tendon Elongation With Plantarflexion Strength Following Surgical Repair.

Little data exist regarding the adverse effects of Achilles tendon (AT) elongation after rupture repair on plantarflexion strength. This study aimed to investigate the effect of AT elongation measured using AT resting angle (ATRA) on the plantarflexion strength in patients with surgically treated acute AT rupture. A retrospective chart review was performed on 40 patients (15 female and 25 female) who underwent open operative repair due to an acute AT rupture. At the final follow-up, AT elongation was assessed using ATRA. Plantarflexion strength (peak torques and angle-specific torques) was measured using an isokinetic dynamometer. All variables were obtained from the operated and unoperated contralateral ankles of the patients. The mean ATRA was greater in the operated ankles (mean, 57 degrees; range, 39-71 degrees) compared with the unoperated ones (mean, 52 degrees; range, 36-66 degrees; P = .009). Except the plantarflexion torque at 20 degrees of plantarflexion (P = .246), all the other angle-specific torques were lower in the operated ankles (P < .05). Peak flexion torque at 30 degrees/s was lower in the operated ankle (P = .002). A negative correlation was found between operated/unoperated (O/N) ATRA and O/N plantarflexion torque ratios at 0 degrees (r = -0.404; P = .01), 10 degrees (r = -0.399; P= .011), and 20 degrees (r = -0.387; P = .014). Postoperative AT elongation measured using ATRA may have a deleterious effect on the plantarflexion strength in patients with surgically treated acute AT rupture. Level IV, case series.

Efficacy of early controlled motion of the ankle compared with immobilisation in non-operative treatment of patients with an acute Achilles tendon rupture: an assessor-blinded, randomised controlled trial

BackgroundEarly controlled motion (ECM) of the ankle is widely used in the non-operative treatment of acute Achilles tendon rupture, although its safety and efficacy have not been investigated properly in...

Proximal and Distal Failure Site Analysis in Percutaneous Achilles Tendon Rupture Repair

Category:AnkleIntroduction/Purpose:Different techniques have been described for Achilles Tendon Rupture repair, but no biomechanical evaluation have been performed separately for proximal and distal suturing techniques.The purpose of this study was to biomechanically analyze 3 proximal and 2 distal suture configurations during a simulated cyclic load and load to failure. It was hypothesized that proximal suturing technique was stronger than the distal one and that the modified double suturing technique was the strongest of all techniques.Methods:A simulated, mid-substance rupture was created 6 cm proximal to the calcaneal insertion in 15 fresh-frozen cadaveric Achilles tendons, obtaining 15 proximal and 12 distal samples. Specimens were tested independently and randomly allocated to different suture techniques: proximal fixation site groups: (A1) classic Dresden technique, (A2) modified Dresden, (A3) double modified Dresden; distal fixation groups: (B1) classic distal suture and (B2) modified distal suture. Repairs were subjected to a cyclic testing (1000 cycles of 50-200 N) and load to failure. Load to failure, cause of failure and tendon elongation was evaluated. Fischer’s test was used as statistical analysis.Results:None of the proximal tendon and 7/12 of the distal samples failed in cyclic testing. The proximal fixation groups demonstrated significantly more strength than the distal groups (p< 0.05) with average failure loads of 598 N, 587 N and 710 N for groups A1, A2 and A3 respectively (A3 stronger than A1 and A2, p=0,035). Groups B1 and B2 failed on average at 416 N and 351 N respectively, p=0.24. The majority of all repairs failed in the suture- tendon interphase.Regarding elongation, no significant differences were found between groups (p=0.57).Conclusion:The distal fixation site in the Dresden percutaneous Achilles tendon repair is weaker than the proximal fixation site. A proximal modified suture configuration increased resistance to cyclic loading and load to failure significantly. A modification in the proximal and distal fixation sites can be suggested to improve repair strength and hopefully achieve a better outcome.

Gastrocnemius Muscle Structure Remodels Within the First Month Following Acute Achilles Tendon Rupture

Category:Sports, Trauma, Achilles TendonIntroduction/Purpose:Two out of three patients Achilles tendon ruptures have limited plantarflexor function 1-year following Achilles tendon rupture. While tendon elongation has been reported as a possible mechanism of functional deficits, the effects of rupture on plantarflexor muscle structure has not been as rigorously investigated. A recent study found that gastrocnemius fascicle length was decreased 6-months following Achilles tendon rupture compared to the uninjured limb. However, the changes in muscle structure following the first month of injury – when the healing tendon is most susceptible to elongation – has not yet been established. The purpose of this study was to quantify the structural changes to the medial gastrocnemius in patients who suffered acute Achilles tendon ruptures and were treated non-operatively.Methods:To test our hypothesis that plantarflexor structure would undergo rapid remodeling following Achilles tendon rupture, we quantified muscle structure in ten patients (9 male, Age: 44 ± 12; BMI: 28.6 ± 6.5) who provide informed written consent in this IRB approved study. We acquired B-mode ultrasound images of the medial gastrocnemius muscle at the initial presentation (week 0), two weeks, and four weeks following the injury. The same investigator acquired all the ultrasound images and measured fascicle length, pennation angle, muscle thickness, and echo intensity. These measurements had a coefficient of variation less than 10%. We compared these structural measurements of the injured muscle at each time point with the contralateral muscle scans at the initial presentation using paired t-tests.Results:Gastrocnemius muscle structure following an acute Achilles tendon rupture differed with the healthy-contralateral muscle throughout the first four weeks following injury (Figure). Fascicle length was 15% shorter (P < 0.001) and pennation angle was 21% greater (P < 0.001) at the presentation of injury (week 0). These differences in fascicle length (P < 0.001) and pennation angle persisted throughout the 4 weeks after the injury (P < 0.008). Muscle thickness changes were not detected at any of the post-injury visits. Muscle quality, measured as mean echo intensity, was 8% lower in the injured limb immediately (P= 0.008) and 11% lower 2 weeks following injury (P < 0.001). At week 4 muscle quality had returned to within 1% of the contralateral limb (P = 0.393).Conclusion:Our findings support our hypothesis that the gastrocnemius muscle fascicles of the affected side would demonstrate shorter length and greater pennation angle than the contralateral control muscle. These findings are a preliminary set of data from a larger clinical cohort of patients that were enrolled in an ongoing 1-year long prospective study. Achilles tendon ruptures elicit rapid changes in the configuration and quality of the medial gastrocnemius, which may explain long-term functional deficits.

Intraoperative Ultrasound Guided Percutaneous Repair of Ruptured Achilles Tendon: A Comparative Study with Open Repair

Category:Ankle, TraumaIntroduction/Purpose:To compare and analyze the clinical outcomes between ultrasound guided percutaneous repair(USPR) and open repair in ruptured Achilles tendon.Methods:We retrospectively analyzed the outcomes between 12 patients with USPR (group A) and 18 patients with open repair (group B), from January 2015 to February 2018. The postoperative clinical evaluations were done by Arner-Lindholm scale, American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score, Achilles tendon Total Rupture score (ATRS), visual analogue scale (VAS) for overall satisfaction and cosmetic satisfaction of scar, and starting time of single heel raise. And we evaluated complications.Results:There was no statistical difference between two groups in Arner-Lindholm scale, AOFAS score, ATRS, starting time of single heel raise (all p>.05). There was statistically higher overall patient’s satisfaction and cosmetic satisfaction in group A than group B (all p<.05). There were 2 cases of Achilles tendon elongation in group A, and 1 case of re-rupture with deep infection and 1 case of superficial infection in group B.Conclusion:The USPR showed not only good clinical outcomes but also high satisfaction and low rate of complications like sural nerve injury. Thus, it is thought that USPR can be considered as an effective surgical treatment options for Achilles tendon ruptures.

Aspirin inhibits adipogenesis of tendon stem cells and lipids accumulation in rat injury tendon through regulating PTEN/PI3K/AKT signalling.

Tendon injury repairs are big challenges in sports medicine, and fatty infiltration after tendon injury is very common and hampers tendon injury healing process. Tendon stem cells (TSCs), as precursors of tendon cells, have shown promising effect on injury tendon repair for their tenogenesis and tendon extracellular matrix formation. Adipocytes and lipids accumulation is a landmark event in pathological process of tendon injury, and this may induce tendon rupture in clinical practice. Based on this, it is important to inhibit TSCs adipogenesis and lipids infiltration to restore structure and function of injury tendon. Aspirin, as the representative of non‐steroidal anti‐inflammatory drugs (NSAIDs), has been widely used in tendon injury for its anti‐inflammatory and analgesic actions, but effect of aspirin on TSCs adipogenesis and fatty infiltration is still unclear. Under adipogenesis conditions, TSCs were treated with concentration gradient of aspirin. Oil red O staining was performed to observe changes of lipids accumulation. Next, we used RNA sequencing to compare profile changes of gene expression between induction group and aspirin‐treated group. Then, we verified the effect of filtrated signalling on TSCs adipogenesis. At last, we established rat tendon injury model and compared changes of biomechanical properties after aspirin treatment. The results showed that aspirin decreased lipids accumulation in injury tendon and inhibited TSCs adipogenesis. RNA sequencing filtrated PTEN/PI3K/AKT signalling as our target. After adding the signalling activators of VO‐Ohpic and IGF‐1, inhibited adipogenesis of TSCs was reversed. Still, aspirin promoted maximum loading, ultimate stress and breaking elongation of injury tendon. In conclusion, by down‐regulating PTEN/PI3K/AKT signalling, aspirin inhibited adipogenesis of TSCs and fatty infiltration in injury tendon, promoted biomechanical properties and decreased rupture risk of injury tendon. All these provided new therapeutic potential and medicine evidence of aspirin in treating tendon injury and tendinopathy.

Adult Acquired Flatfoot Deformity: Anatomy, Biomechanics, Staging, and Imaging Findings.

Adult acquired flatfoot deformity (AAFD) is a common disorder that typically affects middle-aged and elderly women, resulting in foot pain, malalignment, and loss of function. The disorder is initiated most commonly by degeneration of the posterior tibialis tendon (PTT), which normally functions to maintain the talonavicular joint at the apex of the three arches of the foot. PTT degeneration encompasses tenosynovitis, tendinosis, tendon elongation, and tendon tearing. The malaligned foot is initially flexible but becomes rigid and constant as the disorder progresses. Tendon dysfunction commonly leads to secondary damage of the spring ligament and talocalcaneal ligaments and may be associated with injury to the deltoid ligament, plantar fascia, and other soft-tissue structures. Failure of multiple stabilizers appears to be necessary for development of the characteristic planovalgus deformity of AAFD, with a depressed plantar-flexed talus bone, hindfoot and/or midfoot valgus, and an everted flattened forefoot. AAFD also leads to gait dysfunction as the foot is unable to change shape and function adequately to accommodate the various phases of gait, which require multiple rapid transitions in foot position and tone for effective ambulation. The four-tier staging system for AAFD emphasizes physical examination findings and metrics of foot malalignment. Mild disease is managed conservatively, but surgical procedures directed at the soft tissues and/or bones become necessary and progressively more invasive as the disease progresses. Although much has been written about the imaging findings of AAFD, this article emphasizes the anatomy and function of the foot's stabilizing structures to help the radiologist better understand this disabling disorder. Online supplemental material is available for this article. ©RSNA, 2019.

Pattern analysis of a complete Achilles tendon rupture suffered during high jump preparation in an official national-level athletic competition

ABSTRACT Elite athletes are subject to injuries like the Achilles tendon rupture. This injury requires a long recovery process, with no guarantee of returning to the pre-injury level. When a rupture happens during natural life, movement analysis can provide useful insights concerning patterns of rupture to understand and prevent Achilles tendon injuries. Here we determined the pattern of rupture of an Achilles tendon (AT) in an elite high-jumper athlete who ruptured an AT during the straight line running phase in preparation for a high-jump attempt. This study is a novel case report regarding a national-level elite athlete. The main outcomes were kinematics parameters obtained from video analysis. The pattern of the rupture was determined by pixel intensity and outlier analysis. The rupture occurred at 44% of the single stance. The injured leg showed a higher ankle dorsal flexion and knee–ankle ratio, and a lower knee flexion compared to contralateral leg. An eccentric pattern of rupture occurred during the transition from the mid to terminal stance phases of running. The lower knee flexion and the increased ankle dorsal flexion during the stance suggest a loss of knee-ankle coordination. This might have favoured a major elongation of Achilles tendon causing the rupture.