The Foot xxx (xxxx) xxx Please cite this article as: Brijesh Ayyaswamy, The Foot, https://doi.org/10.1016/j.foot.2020.101738 Available online 9 September 2020 0958-2592/© 2020 Elsevier Ltd. All rights reserved. Early Outcome of a Single Peri-Tendinous Hyaluronic Acid Injection for Mid-Portion Non-Insertional Achilles Tendinopathy - A Pilot Study Brijesh Ayyaswamy a, *, Manesh Vaghela b , Elizabeth Alderton b , Haroon Majeed c , Rajiv Limaye b a Department of orthopaedics, North Tees and Hartlepool NHS Trust, Hardwick road, Stockton on Tees, TS18 9PE, UK b North Tees and Hartlepool NHS Trust c Manchester University NHS Foundation Trust A R T I C L E INFO Keywords: Tendonitis injection hyaluronic acid pain swelling outcomes adverse effects ABSTRACT Aim: The aim of this study was to evaluate the effcacy and safety of a single, peri-tendinous injection of hyal- uronic acid for mid-portion, non-insertional Achilles tendinopathy. Materials And Methods: A prospective, open labelled, single center, pilot study was conducted. All patients enrolled received a single peri-tendinous injection of Ostenil Tendon™ (40 mg/2 ml 2% HA with 0.5% mannitol). Outcome measures were Visual Analogue Scale (VAS) pain score and Manchester-Oxford Foot Questionnaire (MOxFQ) scores at 2 weeks and at fnal follow at 12 weeks. Any major and minor adverse effects were recorded. To assess change in VAS and MOxFQ scores, t test and Wilcoxon signed rank test were employed. Results: Seventeen patients were enrolled in this study with a mean follow-up of 12 weeks. Mean pre-injection VAS score was 9.38 cm (9-9.8), which signifcantly reduced post-injection to a mean score of 4.09 cm (2-8) at week-2 stage, and further improved to 3.01 cm (2-3.9) at the fnal follow-up (p < 0.0001). MOxFQ score showed a signifcant improvement from pre-injection value of 67.77 (63.03-72.55) to 31.18 (13-60) at week-2 stage, and further improved to 24.20 (15.73-32.67) at the fnal follow-up (p < 0.0001). The mean improvement from pre- injection to the fnal follow up was 43.57 (34.25-52.90). No adverse effects for injections were recorded. Conclusion: This small series suggests an encouraging response of a single injection of HA as an effective and safe option for non-insertional Achilles tendinopathy. 1. INTRODUCTION Tendinopathy is the commonest pathological condition affecting the Achilles tendon and represents between 55% and 65% of its disorders [1]. It results in loss of normal collagen architecture, which gets replaced by an amorphous and mucinous material with increased glycosamino- glycans and neovascularization [2,3]. This condition has been reported to affect 9% of recreational runners and up to 5% of professional athletes have been reported to end their careers due to the debilitating effects of this codition [4]. Among the general population, the incidence of mid-portion, non-insertional Achilles tendinopathy has been reported to be 2.35 per 1000 in adults and in up to 35% cases a relationship with sporting activity has been reported [5]. High prevalence amongst run- ners indicates a possible mechanical overload as an important etiolog- ical factor. In the literature, different hypotheses are described to explain the pathology including intratendineous degeneration, neovascularisation, and neurogenic infammatory process. The existence of infamma- tory process remains controversial however this concept has somewhat regained its popularity in the recent years [6]. Achilles tendinopathy is also seen in individuals who lead sedentary lifestyles and present no identifable history of mechanical overload, suggesting that overuse is not the only risk factor [7]. In general, it is accepted that non-operative treatment should be the frst-line management in all patients for a minimum of three to six months prior to consideration for surgery, as the symptoms may resolve in up to three quarters of patients [1]. Various non-operative treatment options are available for Achilles tendinopathy, including eccentric loading exercises, shockwave ther- apy, injection therapy and ultimately surgical intervention [8]. Currently; no universal consensus exists on ‘gold standard’ therapeutic intervention. Eccentric exercise appears to offer most evidence of effectiveness for current treatment [1]. Various injection therapies are * Corresponding author. E-mail addresses: brijeshayyaswami@gmail.com (B. Ayyaswamy), maneshvv@hotmail.com (M. Vaghela), bethalderton19@google.com (E. Alderton), haroon. majeed@nhs.net (H. Majeed), rajivlimaye8@googlemail.com (R. Limaye). Contents lists available at ScienceDirect The Foot journal homepage: www.elsevier.com/locate/foot https://doi.org/10.1016/j.foot.2020.101738 Received 22 April 2020; Received in revised form 7 July 2020; Accepted 29 August 2020