tendinosis was used by puddu in 1976 to describe the histological degenerative changes of this condition .
these include loss of the normal collagenous architecture and replacement with an amorphous mucinous material , hypercellularity , increased glycosaminoglycans and neovascularisation .
it was previously thought that inflammation was not an important factor in the disease ; however in recent years , the importance of inflammation in the tendinopathological process has been under re - evaluation , and it is now thought that the inflammatory process is a contributory factor to the development of tendinopathy . as the disease is a combination of both inflammation and degeneration , the term 
tendinitis. the area of degeneration typically occurs between 2 cm and 6 cm from the insertion of the achilles into the calcaneus .
it is probably most accurate to describe the degenerative process as a failed healing response .
tendinopathy is the commonest pathological condition affecting the tendo achilles and represents between 55% and 65% of disorders .
the incidence of this and other overuse injuries is rising as more people regularly participate in recreational and competitive sports , and the duration and intensity of training regimes increase .
the incidence of achilles tendinopathy has been reported to be as high as 37.3 per 100 000 in some european populations .
intrinsic factors such as lower limb malalignment , leg length discrepancy and limited ankle dorsiflexion , as well as extrinsic factors such as training errors and drugs including steroids and fluoroquinolones , have been shown to contribute to the development of non - insertional achilles tendinopathy .
athletes , whether elite or recreational , are the most common group to present with non - insertional achilles tendinopathy .
the condition has been described in association with many different sporting activities , but it is middle- and long - distance runners who have the greatest susceptibility to it . the annual incidence in high - level club runners was found to be between 7% and 9% in a study by lysholm and wiklander .
athletic activity is not , however , the only predisposing factor to the development of achilles tendinopathy . in one series ,
18 of 58 patients with achillodynia had no direct association with sports or vigorous physical activity .
another retrospective study also found various statistically significant correlations between tendinopathy and diabetes mellitus , obesity and hypertension .
the major symptom in non - insertional achilles tendinopathy is pain , which can significantly interfere with function and especially athletic activity . as with other tendinopathies and fasciopathies ( plantar fasciitis and jumper s knee , for example ) ,
the pain is often at its most intense on first moving after a period of rest .
a diagnosis of achilles tendinopathy can usually be made clinically on the basis of history and presentation .
patients often present with pain and swelling on the posteromedial side of the tendon ( fig . 1 ) and tenderness can usually be elicited with palpation over the swelling .
tests for non - insertional achilles tendinopathy can be divided into palpation tests ( tendon thickening , crepitus , pain on palpation , the royal london hospital ( rlh ) test , the painful arc sign ) , and tendon loading tests ( pain on passive dorsiflexion , pain on single heel raise and pain on hopping )
. the painful arc sign , in which a sensitive swelling moves upon ankle movement , indicates tendinopathy rather than paratendonitis . in the rlh test
maffulli et al studied the sensitivity and specificity of palpation , the painful arc sign and the rlh test in 2003 and found that all three tests had good interobserver agreement .
the study proposed that these three tests be used in the clinical diagnosis of non - insertional achilles tendinopathy .
however , there has been concern about selection bias in that paper due to the distinct patient population studied ( male athletes waiting for surgery ) . a later study by hutchinson et
al in 2013 which studyied the ten clinical tests mentioned above found only two of the tests ( location of pain and pain to palpation ) to be sufficiently reliable and accurate for clinical use .
a 2014 meta - analysis concluded that the most appropriate clinical reference standard for diagnosis of achilles tendinopathy needed further investigation .
imaging techniques including ultrasound and magnetic resonance imaging ( mri ) scans can occasionally be useful to identify the nature , location and extent of a lesion .
2 ) , as the pain in achilles tendinopathy seems to be related to areas of neovascularisation .
it has been shown that new , pain transmitting nerve endings ( neonerves ) grow into the tendon with the new vessels , and those treatment modalities which reduce the amount of neovascularisation can lead to a reduction in symptoms .
ultrasound scan showing ventral neovascularisation within the transverse section of the achilles tendon on colour doppler .
equally , treatments that have proven to be clinically effective have subsequently been shown to reduce neovascularisation within the tendon , although the quality of evidence for this has recently been challenged .
both ultrasound and mri scans have traditionally been considered to have similar accuracy in the diagnosis of achilles tendinopathy .
early studies seem to indicate that mri scans are better for characterising degeneration in the tendo achilles .
however , later research has shown equal or better accuracy with ultrasound when compared with mri scans in the detection of tendinopathy .
of note , greyscale ultrasound was found to be more sensitive , whereas colour doppler ultrasound had higher correlation with patients symptoms .
newer imaging modalities such as ultrasound tissue characterisation and sono - elastography have yielded promising initial results in improving sensitivity , specificity and accuracy in diagnosis .
further studies may be needed to investigate their role and application in the management of achilles tendinopathy .
the mainstay of management in non - insertional achilles tendinopathy is conservative , and surgery should only be considered once such conservative measures have failed .
the first step may be to remove the precipitating factors by resting or modifying training regimes .
foot and ankle malalignment may be addressed by orthotics , while decreased flexibility and muscle weakness may be treated by appropriate physiotherapy .
3 ) have been shown to be the most effective treatment for non - insertional achilles tendinopathy . in alfredson s protocol ( the most commonly - used treatment ) , exercises are performed in three sets of 15 repetitions , twice a day for 12 weeks .
a ) starting position for eccentric exercise : ankle in neutral with slight knee flexion .
this regime was demonstrated in a 2009 systematic review , and confirmed in a 2012 meta - analysis which outlined the best pooled data supporting eccentric exercises , with the majority of the studies adopting alfredson s protocol .
, investigators have also found eccentric strengthening to be an effective non - operative intervention in the treatment of non - insertional achilles tendinopathy ; however the proportion of good and excellent results is definitely lower . at present ,
eccentric strengthening has become the treatment of choice for non - insertional achilles tendinopathy , with the greatest amount of evidence for its effectiveness .
it requires a motivated patient but no special or expensive equipment , and has been hailed as 
probably the greatest single advance in the management of this condition in the past 20 years  .
while the most common exercise procedure is alfredson s protocol , isolated eccentric exercises may not work in all patients .
other eccentric protocols such as eccentric  concentric progressing to eccentric ( silbernagel combined ) and eccentric  concentric ( stanish and curwin ) , have been described . in a recent systemic review ,
the silbernagel combined type exercise was found to have results equivalent to the traditional alfredson s protocol .
isotonic , isokinetic , and concentric loading have also been described , but found to be inferior to the eccentric - type exercises . in a prospective randomised controlled study ,
rompe et al showed that eccentric strengthening plus repetitive low - energy shock - wave therapy ( eswt ) was better than eccentric strengthening alone in terms of victorian institute of sports assessment - achilles ( visa - a ) scores and pain ratings at four months .
the proportion of patients who were  completely recovered or  significantly improved on the likert scale was also significantly better in the combined therapy group ( 82% ) compared with 56% in the strengthening alone group .
when compared with eccentric strengthening in a rct , it showed similarly favourable outcomes in achilles tendinopathy , with around a 60% of the patients completely recovered or significantly improved in both of the treatment groups .
the results were significantly better than those in the  wait and see control group .
the success rate of 60% was lower than that seen in other studies evaluating eccentric strengthening , but this may be because one third of the patients in this study were not athletic and results are known to be worse in those individuals .
eswt is normally performed three times spaced at one week apart , with 2000 pulses with a pressure of 2.5 bars and a frequency of eight pulses per second .
the area of maximal tenderness is treated in a circumferential pattern , starting at the point of maximal tenderness .
there appear to be two aspects to the clinical response to shock - waves : one on tissue healing and the other on pain transmission . in the peripheral nervous system
, eswt leads to selective dysfunction of sensory , unmyelinated nerve fibres either directly or through the liberation of neuropetides .
changes in the dorsal root ganglion have also been reported , implicating both a central and peripheral nervous system role in mediating shock - wave - induced long - term analgesia .
increased levels of tissue healing factors tgf-1 and igf - i expression have been shown after eswt in a rat tendinopathy model and a significant decrease in some interleukins and matrix metalloprotienases ( mmps ) have been shown after shock - wave treatment on cultured tenocytes . in a recent systemic review
, there was moderate evidence for equal short - term benefit when compared with eccentric loading , and moderate evidence of superior outcomes when combined with eccentric loading rather than eccentric loading alone .
there is , therefore , both basic science and clinical evidence to recommend eswt as a second - line or adjuvant treatment to an eccentric stretching programme .
various injection therapies have been proposed in the treatment of non - insertional achilles tendinopathy . in a recent systemic review ,
the use of platelet - rich plasma ( prp ) in the treatment of many different conditions seems to be growing exponentially , especially among sports medicine physicians . despite the basic science theories for its effectiveness , the only well - designed rct published on prp in achilles tendinopathy showed no significant difference in pain or activity level in patients with chronic achilles tendinopathy between prp and saline injection at six , 12 or 24 weeks when combined with an eccentric stretching programme.90 a one - year follow - up study of the same group of patients again showed a lack of differentiation between the groups , while yet another paper also demonstrated no difference in the ultrasonographic appearance of the tendons either .
despite what is written above , between one quarter and one third of patients will fail conservative treatment and require surgical intervention .
open surgery for non - insertional achilles tendinopathy has traditionally involved a large incision and excision of all of the tendinopathological tissue , with or without augmentation with a tendon transfer ( commonly flexor hallucis longus ( fhl ) ) .
open surgery has shown varying success rates of between 50% and 100% , with surgery for intratendinous lesions and late - presenting lesions showing significantly fewer good to excellent results .
the main concern with open surgery is the risk of complications . in a large series of 432 consecutive patients from a specialist centre
surgical complications may include skin edge necrosis , wound infection , seroma formation , haematoma , fibrotic reactions or excessive scar formation , sural nerve irritation or injury , tendon rupture and thromboembolic disease .
minimally - invasive procedures aim to reduce these risks.as mentioned above , the pain in non - insertional achilles tendinopathy appears to be related to the neurovascular ingrowth which comes in from the fat pad anterior to the tendon .
minimally - invasive therapies which strip the paratenon from the tendon , either directly or indirectly with high - volume fluid injection , have shown promise in relieving the symptoms of non - insertional achilles tendinopathy .
ventral scraping of the tendon through an ultrasound - guided , minimally - invasive approach has produced good initial results . in one study
multiple percutaneous longitudinal tenotomies , which can be performed under ultrasound guidance , have also been described with good results and with the further advantage of being able to perform the procedure under local anaesthesia in the outpatient setting .
promising initial and even longer - term results ( mean seven year follow - up ) with no complications have been reported for endoscopic paratenon debridement and longitudinal tenotomies .
it has also been noted that patients most often present with symptoms and swelling on the medial side of the tendon , which lead to the postulation that the plantaris insertion or its association with the achilles plays a role in the symptomatology and/or development of the condition , and that releasing or excising it may be an important part of the treatment .
both tendinoscopic and minimally - invasive open debridement with resection of the plantaris tendon have also shown promising results with minimal complications in both elite athletes and regular patients with non - insertional achilles tendinopathy .
there have been no head - to - head comparisons between the different minimally - invasive approaches and therefore it is unclear whether it is necessary to perform longitudinal tenotomies or to excise the plantaris tendon .
however all of the procedures strip the anterior paratenon , so this aspect would appear to be important .
all show good results and minimal complications ; therefore , minimally - invasive surgical treatment would appear to be a useful intermediate step between failed conservative treatment and formal open surgery .
non - insertional achilles tendinopathy is a painful and debilitating condition that can affect athletes and non - athletes alike .
it is not an inflammatory but a degenerative condition , the histology of which is best described as a failed healing response .
the majority of patients will respond to conservative treatment , with eccentric stretching being the safest , cheapest and most effective modality which should therefore be the first line of treatment . for patients who fail conservative treatment ,
minimally - invasive techniques are showing promising results with low complication rates and may be a good option before considering formal open surgery .
no benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article .
 non - insertional achilles tendinopathy is a degenerative condition characterised by pain on activity.eccentric stretching is the most effective treatment.surgical treatment is reserved for recalcitrant cases.minimally-invasive and tendinoscopic treatments are showing promising results.cite this article : pearce cj , tan a. non - insertional achilles tendinopathy . 
 efort open rev 2016;1:383 - 390 . 
 doi : 10.1302/2058 - 5241.1.160024 . 
Introduction
Presentation
Imaging
Non-operative treatment
Operative treatment
Conclusion
Funding