According to the UK MoD, musculoskeletal injuries (MSKI) lie behind around 60% of downgradings and a similar proportion of medical discharges, with the incidence of long-term tendon injuries that do not properly heal in lower limbs alone running at 1.4% – some 2000 new cases – per year in the British military.
Although this is considerably lower than the prevalence of these kinds of injuries among athletes and sports players, where it may reach as high as 50% for some sports, it is markedly higher than the general population and leaves many servicemen and women suffering pain and reduced mobility. Although several therapies are available, including isometric, eccentric, heavy slow resistance exercises and extracorporeal shockwave therapy, treatment often proves inadequate, while the chances of success from surgical intervention can be little better than 50:50.
There is one approach, however, that does seem to hold out more hope. Some centres have produced encouraging results from High Volume Image Guided Injection (HVIGI), a therapy which aims to stop the intrusive new growth of blood vessels and nerve tissue into the tendon that is a feature of chronic tendinopathy. To date there has been no controlled study to provide good evidence to support the use of the injection method on service personnel – at least not until now.
The Biomechanical Associations and Efficacy of Injectable Therapies in Tendinopathy (BEFIT) study is a collaboration between the MoD’s Headley Court Academic Department of Military Rehabilitation (ADMR) and the National Centre for Sport and Exercise Medicine at Loughborough University. Grant funded by the Higher Education Funding Council for England, its main focus lies in a randomised controlled trial (RCT) to examine the effect of high volume injection therapy on Achilles and patellar tendinopathy.
One hundred and eight medically downgraded and non-deployable male patients were selected for the study, aged between 18 and 55, who had been suffering from tendon problems for at least six months, and who additionally had shown little or no improvement with physical rehabilitation and had detectable new blood vessel growth. Female sufferers were excluded from participation, as were those with any other concurrent lower limb problems, who had previous tendon surgery or injection, or were receiving anticoagulant medication.
“One hundred and eight medically downgraded and non-deployable male patients were selected for the study.”
The investigation itself is a double blind, randomised control trial, with the participants divided into three, and each group then receiving one of three possible treatments. One set will be given a low volume (3ml) subcutaneous local anaesthetic sham-control injection, the second a 40ml mix of saline and local anaesthetic, and the third a 40ml injection made up of saline, local anaesthetic and corticosteroid.
Double blind trials are designed to reduce bias in the process and deliver the fairest and most accurate results by ensuring that neither the person administering the treatment, nor the patient receiving it, actually knows which he or she has been given. Clearly, the obvious volume discrepancy means that the clinician giving the injection will easily be able to discriminate between the 3ml control and the 40ml of the two treatments, but with the syringes being prepared elsewhere and by someone else, he/she will remain unaware of which injections contain the steroid, as will the individual patient himself. As a further test at the end of the trial, each participant will be asked which of the three possible treatments they think they received.
Motion capture medicine
The primary goal of the study is, therefore, to see how effective HVIGI using injectable saline in combination with local anaesthetic and with or without injected corticosteroid is as treatment for chronic tendinopathies that have proven unresponsive to other therapies. The researchers’ hypothesis is that both of the high volume injections will yield better results than the 3ml sham-control, and the group receiving the corticosteroid should experience the best results of all.
The study will also look at biomechanical abnormalities between chronic patellar tendinopathy patients and healthy control subjects and additionally seek to identify any biomechanical and/or epidemiological factors that could be used to predict how well an individual may respond to injectable therapy. Doing that calls on the type of motion capture technology that comes straight out of the movies.
The British charity, Help for Heroes, funded a specialised motion tracking laboratory at the Headley Court Defence Medical Rehabilitation Centre (Dmrc) back in 2011, featuring the same kind of Vicon technology that helped bring Paddington Bear to life and generate the breathtaking sequences in Gravity. By placing a series of retro-reflective markers on tendinopathy sufferers and filming them using the laboratory’s near infra-red cameras as they go through a series of predetermined movements, their movements can be captured and faithfully represented on computer.
The experts from the DMRC and Loughborough University hope that analysis of these results will enable them to spot potential tendon pain ahead of time, and accurately forecast how effective treatment using HVIGI would be for someone who is already a sufferer.
With a trial as potentially important as this, which could usher in a step-change in the way military tendinopathy patients are treated in future, getting an accurate gauge of success is obviously vital. Against a baseline established at the outset, outcome measures are subsequently to be taken at six weeks then three, six and finally 12 months on.
The Visual Analogue Scale (VAS) for pain will be used to provide a subjective score for the pain currently being experienced, and involves asking each patient to mark its severity along a 100mm long line, where 0mm represents no pain at all, and 100mm maximal pain. Participants will be asked to complete a validated Victoria Institute of Sport questionnaire – the (VISA-A)55 for Achilles and (VISA-P)1for patellar – to allow direct comparison to be made and enable the data to be used in meta-analyses. In addition, the degree of out-of-place blood vessel formation will be investigated, along with strength and balancing tests and a formal Functional Activity Assessment.
Although how effective this all proves to be remains to be seen, if it does all go according to plan, then it should add significantly to the understanding of the treatment of tendinopathy. Being able to separate, and quantify, the two quite distinct mechanisms of action offered by high-volume injection on the one hand, and the effect of corticosteroids on the other, would represent a major advance for injectable therapy, and could ultimately open the door for its wider use.
For future generations of British Forces, the misery and debilitation of so-called ‘Jumper’s Knee’ may soon be a thing of the past.