Injection therapy in the management of mid-portion Achilles tendinopathy; a review of randomized controlled trials.
Author Dr Dominic Radford MBChB, MRCGP, Msc Sports Medicine, FFSEM RCS Edinbugh, FRACGP
Abstract
Background & purpose: Mid-portion Achilles tendinopathy (AT) is a common condition in athletic and sedentary populations that is often recalcitrant to treatment. Multiple injection therapies have been proposed not all of which have been vigorously tested. The purpose of this review was to identify and appraise all of the published randomized controlled trials (RCT) of injection therapy to assess their effectiveness and to identify topics for future research.
Methods: A computerised Medline and Embase search was undertaken on 4th January 2012 to identify all RCT where injection therapy was assessed in the management of mid-portion AT.
Results:Ten RCT were identified in twelve separate papers dating from 1998. A total of 341 Achilles were included. Injectables under assessment were methylprednisolone, triamcinolone, autologous blood, aprotinin, platelet rich plasma, dextrose, skin-derived fibrobalsts & polidocanol. These were variously directed in or around the tendon structure. Despite methodological shortfalls there was positive evidence for the use of triamcinolone, skin-derived fibroblasts and polidocanol injections.
Conclusion: There is a paucity of level 1 evidence for any Achilles injection. Achilles rupture is a risk using triamcinolone. A pilot study of skin-derived fibroblast shows promise but was poorly designed. Polidocanol aimed at neovascularization demonstrates effectiveness but needs to be reproduced at other institutes. Future research should standardise inclusion criteria and outcome measures.
Introduction
Chronic mid-portion Achilles tendinopathy (AT) is a common condition presenting in both athletic and sedentary populations constituting a significant caseload to sport injury and general practice clinics.1-3 Historically incorrectly termed “tendonitis” however histological studies reveal little inflammatory process within the tendon but rather a degenerate condition.4 5 Thus it is more accurately described as “tendinopathy” or “tendinosis”, in essence a “failed healing response”.6
Macroscopically the tendon loses its shiny appearance, is thickened and exhibits sites of tissue breakdown.7 Histologically there are increased cell numbers and activity, increased extracellular ground substance, loss of normal collagen quality and alignment and the presence of abnormal vascular and neural structures termed neovascularisation.7-9
Ultrasound (US) is the most useful imaging modality demonstrating tendon thickening, degenerative tissue in the form of hyopechogenicity, interstitial tears and neovascularistation with Doppler. Additionally US can be used to guide needle placement during injections.10-12
The aetiology of AT, or indeed any tendinopathy, remains incompletely understood. Various causative factors have been proposed including transient ischaemia, hypothermia, hyperthermia and tenocyte apoptosis.5 Cook et al proposes a model of tendon pathology over a continuum from a reactive tendinitis through to a degenerative tendinopathy.13 A similar hypothesis whereby both inflammation and degeneration act together in a “pathogenic cascade” has been mooted.7 Debate even exists as to where tendon pain arises from. Traditionally thought to arise from microtraumatic tears there is now evidence of neural and vascular causes.9
Primary management involves biomechanical assessment and a strengthening in the form of an eccentric loading program. Developed by Alfredson it has been subsequently modified and boasts the greatest volume of evidence in tendinopathy management.14-18 Alfredson’s programme requires patients to load the tendon eccentrically for 3 sets of 15 repetitions (with knee in extension and flexion) twice a day for 12 weeks; a total of 15,120 repititions!14 The exercises should be painful (four out of ten) and as it become less uncomfortable the patient is to load up with weights in order to address this. Subsequently patient motivation is challenged and even if completed there is a significant failure rate.19
Surgical management varies but usually involves debriding degenerate tissue from the AT, tendon transfer or stripping the neovascular ingrowth.6 20-23 There are relatively high wound complication rates with long rehabilitation process and should not be considered until failure of conservative measures over at least six months.23-25 Many patients would not even consider surgery for this frustrating, painful but ultimately benign condition.
Recently extracorporeal shockwave therapy (ESWT) has been introduced as a management strategy.26 27 Treatment regimes have yet to be standardised but typically involves 3 doses, a week apart, aimed at the most painful tendon region. ESWT is yet to be widely available and its effectiveness is under ongoing review.
Due to the lack of effective, acceptable treatments for AT much attention has been directed towards the injection of various pharmacological agents in and around the Achilles. Many different substances have been trialled with an equally large variety of proposed mechanism of action.28 The purpose of this review was to critically appraise all of the published randomized controlled trials (RCT) to assess the effectiveness of injection therapies and subsequently to identify where future research should be directed.
Materials and methods
A computerised MEDLINE and EMBASE search (1966 to April 2012) was performed using the keywords; Achilles, tendon, tendocalcaneus, tendinitis, tendinopathy, tendinosis, injection, treatment, management, conservative. The search was limited to RCTs in humans and the subsequent references hand searched to include all relevant articles. Each identified journal was critically appraised and summarised by the author and the methodology assessed utilising Jadad scoring.29
Results
Twelve RCT’s, treating 341 Achilles, were identified that fulfilled the search criteria. One of these included both Achilles and patellar tendinopathies but was included as analysis was separate.30 Three published papers identified were from the same clinical trial so have been appraised in unison.31-33
Description of the studies
For the purposes of narrative the studies have been subdivided into 1) cortisone 2) injections into/around tendon and 3) injections aimed at the neovascularisation ventral to the tendon.
Corticosteroids
DaCruz recruited patients attending A&E to study the effects of cortisone injections in those with a clinical presentation of “Achilles paratendonitis”.34 They were randomised to receive either 1ml methylprednisolone 40mg with 1ml 0.25% marcaine or 2ml 0.25% marcaine. Injection was aimed at the paratenon without imaging or blinding. Assessment was reported as double blinded though no details provided as to how this was maintained. All patients received the same follow up advice with regards to post injection care and activity. At 12 weeks post injection those considered to have not responded were crossed over to receive the opposite injection. Outcome measures at 12 weeks included a pain visual analogue score (VAS), an activity and tenderness scores. A total of 23 tendons were evaluated at 12 weeks and although no statistical analysis was performed it was clear that there was no difference in any outcome measure between either group and that non-responders crossed over did not differ either. There were no reported adverse events. This study’s main drawbacks were the lack of clear diagnostic inclusion criteria or blinding and unguided injection technique.
Fredberg et al also looked at the role of cortisone.30 Patients clinically diagnosed from the orthopaedic department were assessed ultrasonographically to confirm a tendinosis. Patients were randomized to receive US guided peritendonous injection of either 20mg triamcinolone in 0.5ml & 3.5ml lidocaine 10mg/ml or 0.5ml 20% intralipid & 3.5ml lidocaine 10mg/ml. The intralipid mimicked the milky appearance of the triamcinolone for blinding purposes. The injections were administered at either side of the thickest portion of tendon. Between 2 to 3 injections were given depending upon response at days 0, 7 and 21. All patients were rehabbed identically. Non responding control patients were offered the steroid injection regime. Outcome measures included US measured maximum tendon diameter and pressure algometry to objectively measure tendon tenderness. Subjective walking pain was also measured up to 26 weeks. A telephone interview was undertaken at 2 years. Only one third of patients referred had ultrasonic changes consistent with tendinosis so ultimately 24 Achilles were included in the study. The steroid group demonstrated significant reduction in tendon diameter, tenderness and walking pain, at 26 weeks. Patients crossed over to steroid exhibited similar response. No changes were observed in the placebo group. Localised fat atrophy was observed frequently after the steroid injection (46%) but was not considered to be troublesome. One patient who received two cortisone injections sustained a rupture; she had been identified as having a granuloma at the calcaneal insertion but ruptured in the mid-portion. This was a generally well designed study but there was no attempt made to demonstrate that the intralipid was not pharmacologically active which could have biased results. The authors concluded that triamcinolone was useful in the short to midterm.
Tendon Injections
The effect of autologous blood injection (ABI) peritendinously was researched by Pearson et al.35 Symptomatic patients with US confirmed AT were randomized to either an eccentric loading program alone or eccentrics and ABI. Bilateral tendonopathic patients had the injection into only one tendon but rehabbed both. Lying prone and without imaging 1ml of 1% lignocaine was injected subcutaneously aiming for the area of maximum tenderness. Leaving the needle in situ 3ml fresh venous blood was taken from the antecubital fossa and administered peritendonously (under low pressure) through the same needle. The patient massaged the injected area for 5 minutes and rested for 48 hours before starting the rehab program. At 6 weeks post procedure a second blood injection was offered if deemed clinically appropriate. The clinically validated Victoria Institute of Sport Assessment-Achilles (VISA-A) was used to measure outcome response up to 12 weeks,36 and a Likert scale questionnaire used to assess discomfort at the time of and at 48 hours after the injection. 28 tendons were assessed at 12 weeks, 19 tendons were injected, ten of them twice following a partial response. All participants demonstrated an improvement at 6 weeks. After this the control group’s response plateaued whereas the injection group demonstrated a further similar improvement but was not statistically significant. There was a recorded 21% rate of post-injection flare in symptoms. This pilot study demonstrated that ABI was safe. Larger sample size could have shown the improvement seen to be significant though any effect could also be attributable to a needling effect.
Brown et al,37 followed up 26 tendons for 12 months following the unguided peritendinous injection of Aprotinin, a bovine derived collegenase inhibitor that had been shown to be successful in treating patellar tendinopathy. Patients with a clinical diagnosis of AT were randomised to receive either 3ml (30,000 kIU) Aprotinin with 1ml 1% xylocaine or 3ml normal saline with 1ml 1% xylocaine. Three injections were given at weekly intervals, administered double blind and all patients were prescribed an eccentric loading programme. Blinded clinical evaluation was performed up to 1 year and involved assessment of tendon tenderness, number of hops and single leg heel raises to pain, return to activity and a patient function rating. At 1 month the VISA-A was undertaken. There was a dropout rate of 7 tendons treated leaving evaluation of a total of 26 at 12 months. An improvement of VISA-A scores was seen in the Aprotinin group however this did not prove to be significant and there was no difference detected in the other outcomes. Itching proved to be a common complication following Aprotinin injections. The authors of this well designed study concluded that there was no perceived benefit from Aprotinin injections.
The effects of platelet-rich plasma (PRP) injections were reported by de Vos et al in three separate papers using the same data set.31-33 Fiftyfour suitable patients were identified clinically and randomized to receive either a PRP or saline. The PRP was prepared from all participants using 54ml of whole blood with 6ml citrate as an anti-coagulant. After centrifuge 0.3ml of 8.4% sodium bicarbonate buffer was added and a sample sent for microbial analysis. 4ml PRP was prepared for injection as was an identical volume of isotonic saline. A covering sheath was applied to the syringe to maintain full blinding. The skin was anaethetised with 2ml 0.5% marcaine subcutaneously. The treating physician imaged the tendon structure with US to identify the degenerative area. Three puncture locations were used to administer five small deposits each into the Achilles aiming for the degenerate tissue. All patients received identical rehab programs which included eccentric loading. Outcomes up to 52 weeks included VISA-A, patient satisfaction, return to sports and eccentric loading compliance. Additionally US evaluation was undertaken up to 52 weeks.32 33 This entailed Doppler scoring of neovascularisation using a modified Öhberg score and ultrasonographic tissue characterisation (UTC) to evaluate tendon structure. All patients involved reported a significant improvement in their VISA-A up to 52 weeks but there was no difference between the active and placebo groups. Similarly there were no differences between either group in any other recorded clinical outcomes, US or UTC and no-one was lost to follow up. No complications were recorded and there was no microbial growth in the samples. These were well designed trials which failed to demonstrate any effect of PRP on AT.
Prolotherapy in the form of hypertonic glucose has been trialled in the management of AT.38 Inclusion criteria included sufficiently symptomatic patients, as determined with the VISA-A with confirmation of mid-portion tendinosis by Doppler US. Patients were randomized to receive Alfredson’s eccentric loading exercises for 12 weeks, prolotherapy or a combination of both. The injections were administered without imaging aiming subcutaneously for the clinically tender points on the tendon. Between 0.5-1ml of solution (20% glucose, 0.1% lignocaine & 0.1% ropivacaine) was injected at each point to a total maximum of 5ml. Injections were repeated at weekly intervals (max 12) until pain-free activity was achieved or further treatment declined. In the combined group treatments were administered concurrently. The VISA-A was used as an outcome up to 12 months. In addition patient symptoms, satisfaction and perceived improvement scores were collected. Costing for all related treatments, including all consultations, were calculated during the yearlong study including for the duration of three months prior to the study start. Forty tendons were available for assessment at 12 months. All participants demonstrated significant improvements, at each assessment, in the VISA-A scores from baseline. Although at 6 weeks there was a significant improvement in the combined treatment arm compared to the eccentric loading group by 1 year there was no difference between any of the three. All groups reported significant improvements in pain, stiffness and activity levels of a similar degree by 12 months though improvements were seen to occur more rapidly in the prolotherapy and combined groups than for eccentric loading group. When incremental improvements in VISA-A were costed, analysis demonstrated that combined treatment was the most economically favourable. The authors of this well designed trial concluded that the use of combined therapy led to more rapid resolution of symptoms and that it was cheaper.
Fibroblasts derived from skin and expanded in-vitro were used in a preliminary study to assess safety and efficacy.39 Patients with US confirmation of AT were prescribed a six month eccentric loading program. Those who failed to make progress were selected and randomized for treatment. All patients had skin samples taken by punch biopsy but only samples from those assigned to the treatment group were sent to the laboratory. Biopsies were treated and grown to obtain in the order of 10 million skin-derived fibroblasts. All patients had 10ml of venous blood taken from their antecubital fossa and centrifuged to obtain a plasma supernatant. Lying prone hypoechoic areas and intratendinous tears were identified by US. All had 5ml bupivacaine 0.25% injected onto the mid-portion ventral Achilles surface. Although the study described itself as double blind in fact it was only in the treatment group that the needle was repositioned to deliver 2ml each of skin-derived fibroblasts and plamsa supernatant intratendinously aiming for the degenerate areas. All were prescribed an eccentric loading program. Outcome measures used were VAS symptoms scoring and the VISA-A and follow up was for 6 months post injection. Forty tendons in total were included in the study, 24 from unilateral Achilles and eight patients with bilateral. Statistical analysis demonstrated that at 6 months there was a significant improvement in VAS and VISA-A compared to controls in those with unilateral symptoms. Patients with bilateral symptoms failed to show any difference in outcome. There were no adverse reactions reported. The main disadvantage of this study was that only the treatment group received the injection of plasma and fibroblasts thus it is impossible to know what effect the further needling and plasma had. This was a pilot study however that demonstrated no adverse effects from the procedure.
Neovascularisation
The sclerosing agent polidocanol was used to target areas of neovascularisation located on the ventral surface of the Achilles.40 Twenty patients with a clinical and US diagnosis of AT were recruited and randomized to either Polidocanol (5mg/ml) or a mixture of Lidocaine hydrochloride (5mg/ml) and Adrenaline (5µg/ml) to mimic the short term effect of obliterating the neovascularisation for blinding purposes. Injections were performed under US guidance with colour Doppler on. The needle tip was directed onto the ventral surface of the Achilles targeting the Doppler areas of neovascularisation. Small fractions of solution were injected until the Doppler signal disappeared. This was repeated until all Doppler signal had disappeared with a maximum of 4ml injected. Upto 2 treatments were prescribed 3-6 weeks apart depending upon response. No specific rehab exercises were prescribed. All unsatisfied control patients were subsequently offered treatment with the Polidocanol and reassessed. Outcome measures included pain VAS, Doppler US and patient satisfaction questionnaires. Patients were followed up on average for 3 months. Within the Polidocanol group there was a significant improvement in the VAS and all reported satisfaction by the end of their treatment. No neovascularisation was present immediately after their last injection. There was no significant improvement in VAS seen in the control groups and none were satisfied. All controls were subsequently treated with Polidocanol after which a significant reduction in VAS was observed, nine out of ten were satisfied and no Doppler signal remained. The unsatisfied patient still had Doppler signal. No adverse events or complications were observed. The authors concluded that targeted injections of Polidocanol reduced tendon pain and that there was a correlation between the presence of neovessels and pain. Although a well designed trial no attempt was made to prove that the control intervention did not adversely affect the Achilles which would have biased the results in favour of Polidocanol.
To compare these Polidocanol injections to surgery the same authors performed similar injections against surgical stripping of the ventral surface soft tissue in order to physically remove the neovascularisation.41 Twenty patients diagnosed with AT on clinical and US were randomly allocated to have either the Polidocanol 10mg/ml injections (upto 2ml) aiming for the neo vessels, as before, or the surgical management. Surgery consisted initially of 5-10ml xylocaine aiming for the lateral and ventral tendon sides. Doppler US had been used to identify the most proximal and distal areas of neovascularistaion and the skin marked accordingly. Then, following a lateral incision, a complete release of the soft tissue adjacent to the ventral surface of the Achilles between the markers was performed. Surgery was undertaken only once whereas the Polidocanol was injected, if symptoms persisted every 6 weeks for 26 weeks. No specific rehab exercises were prescribed. Post procedure rehab differed slightly for the first two weeks but thereafter no restrictions on activity were imposed. Outcome measures included a VAS of tendon loading pain and satisfaction questionnaires and patients were followed up for 6 months. At the 12 week assessment both groups had achieved a similar significant improvement in VAS and at 6 months 6/9 and 10/10 of the Polidocanol and surgical groups respectively were satisfied. The authors concluded that repeated in the mid-term Polidocaonol injections were as effective as the surgical procedure in this unblinded trial.
The same authors also studied the effects of two different concentrations of Polidocanol, in a double blind trial, to determine an optimal dosage and treatment duration.42 Fiftytwo tendons were identified as having AT by clinical and US examination. Patients were randomised to receive upto 2ml of either 5mg/ml or 10mg/ml of Polidocanol injected under US guidance into the ventral surface of the Achilles until all Doppler neovascularisation had disappeared. No specific rehab program was prescribed but patients were permitted to resume normal activity after 14 days. A maximum of five treatments were administered at 6-8 week intervals until patient satisfaction was achieved. Outcome measures included pain VAS, patient satisfaction, number of treatments required and total Polidocanol volume administered. Every tendon was evaluated ultrasonically immediately before and after each treatment. Follow up was for an average of 14 months but varied between 2 and 35 months. There was a statistically significant improvement in all patients VAS from before and after their treatment with no difference between groups. There were no significant differences seen between any of the outcomes between either group. All patients reported that they were satisfied with their treatment but to achieve this some patients in either group required 5 injections, 2 more than the original proposed protocol allowed. There were no reported adverse effects. The authors of this well designed trial concluded that there was no advantage to using a larger does so recommended that 5mg/ml was adequate.
Discussion
Mid portion AT is a common condition in both active and sedentary individuals which is often recalcitrant to treatment.1-3 Impact exercise is a major risk factor and with rising population activity levels increased incidence rates are to be expected.
There remain many unanswered questions with regards to its aetiology, pathophysiology and origin of tendon pain.5-8 12 13 28 43 Future research into these areas will facilitate the development of effective treatment strategies. Such research should examine whether all tendinopathies are the same and can hence be managed similarly. Alternatively an overuse AT in an athletic individual may differ from that arising spontaneously in a sedentary person in which case treatment may need to be individualised accordingly. Similarly researchers should establish if all tendinopathies throughout the body are pathophysiologically the same entity.
Traditionally AT has been a clinical diagnosis. However it has been demonstrated that even experienced physicians made an inaccurate diagnosis up to two thirds of the time and hence imaging confirmation should be a prerequisite in trial design.30 Pragmatically it also makes sense for injection therapy to be delivered under US guidance as previous studies have highlighted improved needle placement accuracy.44
Pain is the major presenting complaint along with associated loss of function in AT. Subsequently the validated reproducible VISA-A and VAS outcome measures should be the gold standard along with satisfaction scores.36 45 Tenderness is rarely an issue to the patient and so have less value as a measurement. Little correlation has been demonstrated between the degree of image changes and patients symptoms so it is harder to make a strong case for imaging as an outcome measure.46-48 However pragmatically if a therapy was shown to return to a more “normal” looking tendon then as an objective outcome it would add weight to its effectiveness.
Given the prevalence of AT it is perhaps surprising so little high level evidence exists to back up treatment options. High load eccentric exercises possess the best level of evidence of effectiveness demonstrable in RCTs.14-17 Future RCTs for injection therapy should therefore use eccentric loading as the control intervention.
There was conflicting evidence regarding the effectiveness of corticosteroids in the management of AT. Given the wealth of evidence demonstrating a positive short term effect on symptoms in other tendons49-51, it is surprising that DaCruz failed to reproduce this using methylprednisolone34 and this probably reflects poor trial design. Fredberg’s superiorly designed research did show a positive short term effect.30 However they also had one Achilles rupture which would be considered a severe complication. Many studies have reported post steroid tendon rupture and consequently cortisone injections are now contraindicated in or around the Achilles.52 However research into the mechanism by which steroids reduce tendon pain might be of use in developing safer alternative therapies.
Pearson failed to demonstrate an effect with autologous blood injected peritendonously.35 but a larger sample size may have shown statistical significance. Other non randomized studies of ABI for medial and lateral epicondylosis have shown positive effects where blood has been injected intratendinously in association with tendon needle fenestration and perhaps this would be suitable for the Achilles though researchers must be cautious of precipitating a subsequent rupture.53 54 From personal experience ABI is most effective when combined with an aggressive, progressive loading program post injection. Additionally the effect of needle tendon fenestration should be examined independent of ABI as this would produce localised bleeding similar to the ABI effect.
Aprotinin has previously been primarily used as an antifibrinolytic agent during surgery to prevent post-operative bleeding.55 Due to its action as a collegenase inhibitor it was theorised to be beneficial in reducing the excessive matrix metalloprotease activity demonstrated in established tendinopathy.56 This well designed trial did not show significant improvements but at 1 month there was an non-significant improvement in VISA-A and perhaps with greater patient numbers this would have proven significant. The Aprotinin was placed peritendinously and maybe would have proved to be effective if injected within the tendon structure. However subsequently Aprotinin has been withdrawn worldwide after a multi-centre trial demonstrated a significant increased mortality rate when used in high-risk cardiac surgery.57 Therefore any further research in this area would be dependent on identifying a safer alternative agent.
PRP injected directly into the tendon in multiple pockets did not prove to more effective than saline over 1 year follow up. This double blind trial employed multiple subjective and objective outcome measures and the authors could not recommend using this popular new therapy. Much debate remains as to the most appropriate preparation procedure or dosage as well as to the necessity of fixing substrates and it remains possible that alternatives could prove to be effective.58 59 There are few high quality trials but a positive effect over 1 year was seen with a PRP preparation randomized against cortisone in the treatment of lateral epicondylosis.60
Hypertonic glucose injected onto the tendon surface proved to be as effective as the eccentric loading exercises and combination treatment shown to be the most cost effective.38 A non randomized study also demonstrated significant improvements in pain scores and normalisation of tendon structure on US in Achilles tendons injected intratendinously with a dextrose solution.61 Similarly in a pilot study dextrose injected intratendinously into the patellar tendon also showed positive effects.62 Hypothetically the glucose acts osmotically to initiate inflammation in order facilitate a healing response. This could prove to be a safe treatment option and future research should attempt to replicate these findings. Use of imaging to accurately guide needle placement would be favourable and evidence of tendon structure improvement on imaging would further enhance its credentials. The requirement for repeated injections could prove to be costly however.
The use of skin derived fibroblasts injected into the tendon introduces a potential new avenue for research.39 Pilot animal studies have demonstrated promising results using stem cells in managing tendon injuries.63 64 It was a shame that in the study the control group did not receive the injection of the plasma supernatant as then the positive effect could have been attributed solely to the fibroblast cells. Larger trials are needed in order to establish the efficacy and safety of such treatments.
Polidocanol is a sclerosing agent which also has a local anesthetic effect and has traditionally been used in the management of varicose veins.65 It’s action is to cause thrombosis within the vessel but can have this effect from outside the vessel. Although there is much debate as to the cause of pain in tendinopathy there is evidence of a neurological component.43 A previous pilot study, by the same authors, had theorised that sclerosing blood vessels within the neovascularisation would subsequently necrose the associated neurological structures and reduce the tendon pain.66 Their study demonstrated midterm reduction in symptoms and improved function compared to a combination of lidocaine and adrenaline.40 Furthermore a 2 year follow up prospective study by the same authors with the same treatment showed 37/42 satisfied and returned to premorbid activty levels and on US significant reduction in tendon thickness and more “normal “ look.67 However these very favourable results were not emulated in another similar non-controlled study.68 It seems unlikely that the adrenaline/lidocaine control would have had a detrimental effect on the Achilles and thus biased the results but research confirmation of this would be ideal. Additionally it would be reassuring for other centres to emulate these positive results.
There are issues with licensing of Polidocanol in the UK and other countries which may curtail future research. The hypothesis was that tendon pain was originating from the neovascularisation and that obliterating them would reduce the tendon pain which was borne out in their studies. An alternative method of destroying these vessels has been described by Chan et al whereby a large volume of fluid upto 50ml (10ml bupivacaine, 40ml saline and 25mg hydrocortisone) is injected onto the ventral surface of the Achilles to mechanically strip away the neovascularisation from the tendon and was shown to obliterate the Doppler signal and reduce symptoms in short to mid-term.69 70 If this is a purely mechanical process then is no reason why similar results could not be achieved with just the saline solution thus negating the use of cortisone next to the Achilles with the subsequent rupture risk.
Conclusion
There is a surprising paucity of level I evidence for injection management of AT. Guided Polidocanol injections aimed at the neovascularisation has demonstrated repeated effectiveness in the midterm at reducing pain with low risk of complications. Similar results from other institutions would be reassuring. Repeated hypertonic glucose injections onto the tendon surface also shows similar efficacy to eccentric loading exercise and both used in combination may offer quicker, cheaper recovery but requires further research to replicate results. Skin derived fibroblasts with blood plasma injected into the tendon structure has been shown at a pilot level to induce a positive response and requires further research into safety and effectiveness. Cortisone in the form of triamcinolone has been shown to be effective in the short to midterm with evidence of improved tendon structure but the risk of rupture negates its benefits.
Competing interests
There were no competing interests.
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