Treating Achilles tendon pain and function – A feasibility study of High-Volume Ultrasound Guided Injections Verses Eccentric Loading Exercises

Abstract

Introduction Non-insertional Achilles tendinopathy is a common overuse injury which affects the midportion of the Achilles tendon. It is frequently seen in patients between the age of 30-50 years who participate in sport or other physically demanding leisure or work activity. It is characterised by pain, impaired function and swelling around the affected tendon. The most common non-operative treatment is an eccentric loading exercise programme which has been shown to give variable short and long-term results. However, it is long (12 weeks), laborious (twice a day 7 days per week) and sometimes painful to perform. As an alternative some authors have shown a reduction in pain and improved function by injecting a high volume of saline around the effected tendon using ultrasound guidance. Unfortunately, the quality of these studies is poor, with no Randomised Control Trials to date. Therefore, the aim of this study was to examine the feasibility of conducting a future RCT, comparing high volume ultrasound guided injections of saline solution (HVUGI) with eccentric loading exercises for the treatment of non-insertional Achilles tendinopathy. Method Thirty-three patients took part in a two-arm randomised feasibility study. They were individually randomised via an online computer randomiser to either a treatment group who received a HVUGI or a control group who carried out a 12-week eccentric loading exercise programme. Primary outcomes included eligibility rate, recruitment rate, retention rate and adverse events. Secondary outcomes included measuring the effect on pain and function of HVUGI compared with eccentric loading exercises using the VISA-A (Victoria Institute of Sport Assessment Achilles) patient reported outcome measure. In addition, the effect of the treatment and control interventions on tendon thickness and neovascularity were measured. In the control group, adherence to the exercise regime was measured through a self-reported diary. Results During a six-month period 63 patients were referred to the department of orthopaedics in a large Scottish Teaching Hospital with Achilles tendon pain. Of those, 43 (68%) were considered eligible and 33 (77%) agreed to take part in the study. Of the 33 randomised (treatment group =14, control group 19) two were excluded (1 from each group) because of abnormal ultrasound scans. Eight subjects were lost to follow-up at 12 weeks resulting in a retention rate of 74% (n=23). Adherence to the eccentric loading programme was 74% when recording the number of exercise sessions completed as a percentage of the total suggested. Although improved function and reduced pain were observed in both groups, reflected by an increase in the mean VISA-A score, no significant difference was noted between the groups. No differences were observed in the secondary physiological measurements of tendon thickness and neovascularity either. However, caution regarding the outcome measures should be exercised due to the purposely small sample size. Conclusion This study identified some key issues which could challenge the feasibility of carrying out a future RCT. This included issues around recruitment, retention and adherence to the eccentric loading exercise programme. It was also observed that this study failed to assess any early improvements in function and reduction in pain when comparing the control and treatment groups. Additionally no economic evaluation was carried out as part of this study and should be a future consideration. Therefore, it is suggested that a pilot study is carried out with modifications made to improve areas of deficit and implement changes which include earlier evaluation of pain and function and an economic evaluation. Only if the areas of deficit show improvement to an agreed threshold should a future RCT be considered.