Achilles tendinopathy is a common musculoskeletal condition characterized by pain, lower muscle strength, gait abnormality, and reduced quality of life. There are two categories of Achilles tendinopathy: insertional Achilles tendinopathy and mid-portion Achilles tendinopathy. Currently, mechanical loading programs are considered the standard of care for the population with Achilles tendinopathy. Extracorporeal shockwave therapy (ESWT) is considered a secondary conservative treatment for tendinopathy as it is effective and safe. It can be used either as a monotherapy or as part of a multimodal treatment plan. ESWT has been extensively studied in orthopedics, where it was shown to intensify fracture healing and successfully treat overuse conditions of tendons and fascia. It is believed that shockwaves have both mechanical and cellular effects that ultimately result in the repair of damaged tendinous tissue and improved function of the Achilles tendon. However, there is a lack of consistency in the literature surrounding the effectiveness, especially the protocols. Therefore, we enrolled 36 patients with a diagnosis of Achilles tendinopathy, using radial ESWT (0.48 mJ/mm2, 2,000 shockwaves, 10 Hz, 1.6 bars, 2 sessions once a week). Freedom from pain was experienced by 16.7% of these participants, and there was a significant decrease in pain in all of them.

BACKGROUND: Paratenon preserving techniques to facilitate acute Achilles tendon rupture repair (AATR) functions by maintaining vascularity and biology for optimal healing response. Therefore, the purpose is to evaluate the outcomes following paratenon preserving repair of the midsubstance AATR. The hypothesis was that paratenon-preserving techniques demonstrate high return to play rates and low complication rates for the repair of the midsubstance AATR.
METHODS: A systematic review of the PubMed, Embase, and the Cochrane Library databases was performed by two authors using specific search terms and eligibility criteria. The assessment of the evidence was two-fold: level and quality of evidence. A meta-analysis of proportions for the various complication rates was performed using the restricted maximum likelihood method following the Freeman-Tukey double-arcsine transformation. Fixed effects models were employed if I2 < 25% (low heterogeneity), and random effects models were employed if I2 ≥ 25% (moderate to high heterogeneity).
RESULTS: The pooled return to play rate was 90.3%. The pooled rerupture rate as reported was 0.9% (best-case scenario 0.8% and worst-case scenario 6.8%). No meaningful subgroup analysis for rerupture rates could be performed based on the meta-regression. The pooled complication rate other than reruptures was 4.8%. The pooled infection rates were 0.3%, DVT rates were 1.6%, and sural nerve injury rates were 0.3%.
CONCLUSIONS: Paratenon preserving techniques that are minimally invasive in nature demonstrated safe and favorable outcomes with high return to play rates and low complication rates for the repair of the midsubstance AATR.

Understanding tendon mechanical properties, such as stiffness and hysteresis, can provide insights into injury mechanisms. This research addresses the inconsistency of previously reported in-vivo and in-vitro tendon hysteresis properties. Although limited, our preliminary findings suggest that in-vivo hystereses (Mean ± SD; 55% ± 9%) are greater than in-vitro hystereses (14% ± 1%) when directly comparing the same tendon for the same loading conditions in a sheep model in-vivo versus within 24 h post-mortem. Overall, it therefore appears that the tendon mechanical properties are affected by the testing environment, possibly related to differences in muscle-tendon interactions and fluid flow experienced in-vivo versus in-vitro. This communication advocates for more detailed investigations into the mechanisms resulting in the reported differences in tendon behaviour. Overall, such knowledge contributes to our understanding of tendon function towards improving modelling and clinical interventions, bridging the gap between in-vivo and in-vitro observations and enhancing the translational relevance of biomechanical studies.

UNASSIGNED: Approximately 6% of people will report Achilles tendon pain during their lifetime, and one-third of these individuals will have Achilles insertional tendinopathy (AIT). For patients who have failed conservative treatment, surgical repair is performed. Achilles tendon repair can occur through various techniques, including a single-row or double-row repair.
UNASSIGNED: To determine if there are significant advantages to double-row repair over single-row repair with respect to biomechanical and clinical outcomes.
UNASSIGNED: Systematic review; Level of evidence, 3.
UNASSIGNED: A systematic review of the literature was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. An electronic search of the EMBASE and PubMed databases was performed for all studies related to surgical treatment of AIT, which yielded 1431 unique results. These included both biomechanical and clinical studies. Clinical studies in which patients were not diagnosed with AIT, underwent surgery for repair of acute Achilles tendon rupture, or studies that included additional procedures such as a concomitant flexor hallucis longus transfer were excluded. Eligible studies were independently screened by 2 reviewers. A risk-of-bias assessment was conducted using the Cochrane Risk Of Bias In Non-randomized Studies-of Interventions and risk-of-bias tool for randomized trials tools.
UNASSIGNED: A total of 23 studies were included, 4 of which were biomechanical studies and 19 were clinical studies. Biomechanical comparison found that there was a significant advantage to using double-row versus single-row fixation with respect to load at yield (354.7 N vs 198.7 N; P = .01) and mean peak load (433.9 N vs 212 N; P = .042). There was no significant difference between double-row and single-row repair with respect to load to failure. Significant heterogeneity of the studies did not allow for a statistical comparison of the clinical outcomes between double-row and single-row repairs.
UNASSIGNED: Although biomechanical studies favor double-row repair for AIT, the current data available on the clinical outcomes are not sufficient to determine if there is a clinical advantage of double-row repair. Larger, prospective randomized controlled trials utilizing validated outcome measures are needed to further elucidate whether the biomechanical advantages associated with double-row repair also translate into improved patient-reported outcomes.

Tendons, complex fibrous structures, are subjected to great tensions, which can give rise to the so-called tendinopathies. This study aimed to evaluate photobiomodulation and human Amniotic Membrane applied as single or combined therapies to treat induced Achilles tendon lesions. Seventy-five rats were divided into five groups (n=15): C- control Sham surgery; I- tendon injury; LA- tendon injury treated with photobiomodulation; AM- tendon injury treated with Amniotic Membrane; LAM- tendon injury + photobiomodulation and Amniotic Membrane, subdivided into three groups (n=5) with analysis at 3, 7, and 14 days. The tendon injuries were made with a 20 g weight released from a mini guillotine onto the ankle in dorsiflexion. AM and LAM groups received an Amniotic Membrane fragment while LA and LAM groups received transcutaneous photobiomodulation, using a 660 nm wavelength laser. The inflammatory cells showed statistical differences between groups C and I (p<0.05), I and AM (p<0.01), I and LA (p<0.05), and I and LAM (p<0.01). Both photobiomodulation and Amniotic Membrane were shown to enhance tendon repair, and the association of photobiomodulation plus Amniotic Membrane was the most effective treatment. We conclude that the association of photobiomodulation plus Amniotic Membrane was effective in accelerating and improving the tendon regeneration process.

OBJECTIVE:  This study aimed to investigate the effect of the low-intensity pulsed ultrasound (LIPUS) on the healing of Achilles tendinopathy in a rat model induced by type 1 collagenase.
METHODS:  The study was conducted on 144 Achilles tendons of 72 Wistar albino female rats with typical activity and weighing 300-350 g. The model of Achilles tendinopathy was created by injecting type 1 collagenase. According to the sampling time, 4 groups served as the control group, while 8 groups received treatment at varying periods. Low-intensity pulsed ultrasound therapy was initiated in 8 groups at 1, 7, and 15 days. Treatment was extended for 1 and 2 weeks. Achilles tendons were removed from the treatment and control groups on the 15th, 21st, 30th, and 45th days for biomechanical and pathologic examination.
RESULTS:  Compared to the control groups, LIPUS treatment administered in the first days of the proliferation phase increased tensile strength by approximately 30%, modulus of elasticity by approximately 53%, fibrillar appearance by 53%, and inflammation by 53%-33% in a shorter time. It was also demonstrated that starting treatment in the first days of the proliferation phase resulted in comparable success even with 1-week treatment compared to 2-week treatment.
CONCLUSIONS:  Low-intensity pulsed ultrasound therapy can provide positive results in managing Achilles tendinopathy in the rat model. Its capacity to shorten recuperation time has piqued the interest of conservative treatment approaches. As a result, more clinical research is required. Cite this article as: Kurtulmuş T, Çelebi ME, Bektaş E, Arican ÇD, Kucukyildirim BO, Demirkol M. Effect of the low-intensity pulsed ultrasound therapy on healing of Achilles tendinopathy in a rat model. Acta Orthop Traumatol Turc., 2024;58(2):102-109.

Background: The aim was to assess the diagnostic accuracy of DECT in diagnosing Achilles tendon tears, using MRI as the reference for diagnosis. Methods: This feasibility study conducted prospectively at a single center included consecutive patients suffering from ankle pain who underwent DECT and MRI between April 2023 and October 2023. A total of three radiologists, blinded to the patient\'s clinical data, assessed the images. Achille Tendon injuries were diagnosed in case of thickened and inflamed tendons or in case of a partial or complete tear. Diagnostic accuracy values of DECT were calculated using a multi-reader approach. Inter-observer agreement was calculated using k statistics. Results: The final study population included 22 patients (mean age 48.5 years). At MRI, Achille\'s tendon lesion was present in 12 cases (54.5%) with 2 cases of complete rupture, 8 cases of partial tear (5 with tendon retraction), and 2 cases of tendon thickening. The mean thickness of injured tendons was 10 mm. At DECT, R1 was allowed to correctly classify 20/22 cases (90.9%), R2 19/22 cases (86.4%), and R3 18/22 cases (81.8%). At DECT, the mean thickness of the positively scored tendon was 10 mm for R1, 10.2 mm for R2, and 9.8 mm for R3. A very good agreement was achieved with regard to the evaluation of tears (k = 0.94), thickness (k = 0.96), and inflammatory changes (k = 0.82). Overall agreement was very good (k = 0.88). Conclusions: DECT showed a good diagnostic performance in identifying Achille\'s tendon tears, with respect to MRI.

BACKGROUND: There are many adhesion barrier materials, cross-linked or non-cross-linked hyaluronic acid (HA), used during surgeries.
OBJECTIVE: This study investigates the efficacy of cross-linked and non-cross-linked HA in preventing Achilles tendon adhesions. We hypothesized that non-cross-linked HA may be more effective than cross-linked HA in preventing Achilles tendon adhesions following injury and repair.
METHODS: Twenty male Sprague Dawley rats, totaling 40 legs, underwent Achilles tendon transection and repair. Following the surgery, they were treated simultaneously with cross-linked and non-cross-linked HA formulations. The rats were divided into four groups: a positive control group, a group treated with BMC non-cross-linked HA gel, a group treated with DEFEHERE cross-linked HA gel, and a group treated with ANIKA cross-linked HA gel. Four weeks after surgery, macroscopic evaluation of peritendinous adhesion and histological analysis were conducted to assess the effectiveness of the treatments.
RESULTS: Non-cross-linked BMC HA demonstrated superior efficacy in preventing tendon adhesions compared to cross-linked HA and control groups. Histological analysis confirmed reduced adhesion severity in the non-cross-linked HA group (P < 0.05). The findings support the potential of non-cross-linked HA as a treatment to inhibit tendon adhesions. Further research, including clinical trials, is warranted to validate these results in human subjects.
CONCLUSIONS: Non-cross-linked BMC HA had significantly lower tendon adhesions parameters and better healing scores in histological analysis than cross-linked HA and control group did. Non-cross-linked HA holds promise as a potential treatment to inhibit the formation of such adhesions.

Achilles tendon reconstruction is an effective method of repairing Achilles tendon rupture defects. We introduce a new approach for Achilles tendon reconstruction using transversal calcaneal anchored autogenous semitendinosus tendon graft. The study aimed to evaluate the clinical role of this new Achilles tendon reconstruction. We retrospectively enrolled patients who underwent Achilles tendon reconstruction using transversal calcaneal anchored autogenous semitendinosus tendon graft for acute Achilles tendon rupture defects from 2016 to 2021. The clinical and radiological results were assessed at the preoperative and the final postoperative follow-up with Visual Analog Score (VAS) scores, American Orthopaedic Foot & Ankle Society (AOFAS) scores and Achilles tendon Total Rupture Scores (ATRS). Besides, at the last postoperative follow-up, the difference in ankle range of motion between the two side of the patients and the incidence of postoperative complications were recorded. Results revealed patients had significantly lower VAS and higher AOFAS and ATRS (P < 0.01). Compared to the healthy ankle, the operative ankle showed significant deficits in ankle range of motion (P < 0.01). Additionally, radiological results showed no noticeable signs of tunnel enlargement in the calcaneus and no patient had re-rupture. Transversal calcaneal anchored Achilles tendon reconstruction with free semitendinosus tendon autograft is an effective treatment option for patients with acute Achilles tendon rupture with large defects and have high postoperative exercise demands.

BACKGROUND: Acute closed midsubstance Achilles tendon rupture(ACMATR) is common, with various treatment methods developed over time. We retrospectively compared the two mini transverse-incision repair (2MTIR) with percutaneous repair (PR) to determine which method yields better results.
METHODS: All cases meeting criteria from 2018 to 2021 in our hospital were included and followed up for 1 to 5 years. A final questionnaire with multiple indexes was conducted via phone call. Comparative analysis of these indexes between the two groups was performed using IBM SPSS Statistics (V.26). Continuous variables that passed tests for normality and equal variance were compared using the Student\'s t-test. Ranked data were compared using the Mann-Whitney U test. Categorical variables were tested with the chi-square test or Fisher\'s exact test. A p-value of less than 0.05 was considered statistically significant.
RESULTS: There was one rerupture in the PR group. The final indexes for \"Tightness Feeling\", \"Heel Rising Strength\", and \"Foot Numbness\" were statistically different (P < 0.05) between the two groups. The \"Re-rupture\" and \"Return to Sports\" indexes showed no statistical difference (P > 0.05).
CONCLUSIONS: The 2MTIR technique provided a technically straightforward, minimally invasive procedure with well-preserved paratenon and direct end-to-end firm fixation in cases of ACMATR. It resulted in very low complications, easy rehabilitation, and full weight-bearing as early as 5-6 weeks postoperatively, yielding better functional outcomes compared to the PR technique in the 1-5 year follow-up.
BACKGROUND: The study was preliminarily registered and approved by the University of Hong Kong-Shenzhen Hospital Ethical Board with Project number: hkuszh2023074 on May 4, 2023.