Category Archives: Health Technology

A physio in your pocket

By Navraj S Nagra and Maxime Cox

Knee replacement is regarded as one of the most sucessful medical interventions (1); over a hundred-thousand knee replacements were performed across the UK last year (2). This number is ever-increasing in the context of an ageing population (2). Whilst knee replacement is undoubtedly effective, a key and often variably implemented part of rehabilitation is the subsequent physiotherapy (3).

Current physiotherapy provision has several problems. Firstly, it is expensive (4). Secondly, there is a shortage of physiotherapists in the NHS. Models have shown that an extra 500 physiotherapists need to join the workforce each year just to keep track with demand (5). As a result, patients will only see a physiotherapist once or twice after a knee replacement. Thirdly, a significant proportion of patients have poor compliance to physio (6).

Limited availability, compounded by poor patient compliance, results in patient complications such as reduced range of motion within their artificial knee joint, persistent pain, and muscle weakness longer term (3). These problems contribute to the 30% of patients who report dissatisfaction with their knee replacements – consuming further NHS resources in their subsequent management (7).

Therefore, the NHS stands to gain from solutions which will improve outcomes following knee replacement.

Recently we have noticed a rising trend for the use of technology in the realm of enhanced recovery after surgery, particularly in orthopaedics. For example, specific to knee replacements – Darzi et al. have investigated the use of wearable sensors for early identification of patients who are developing complications after surgery (8), whilst Negus et al. have looked at using the proprioceptive technology within the Nintendo Wii games console for home-based rehabilitation with a focus on balance and proprioception (9).

But what about patients who do not have a games console in their living room? And is there a more cost-effective way to monitor and help patients rather than using expensive wearable sensors that are easily mislaid?

With powerful smartphones being ubiquitous in modern society, our question is whether we can solve the physiotherapy shortage and poor patient compliance with mobile health (mHealth) solutions. Through mHealth, it is possible to turn a patient’s mobile phone into their own personal physiotherapist. Some companies already offer physiotherapy solutions, showing example videos via mobile platforms, such as BlueJay PT, PhysioTools and Physiotec, amongst others. However, the efficacy of existing platforms has not been evaluated through a published trial at the time of writing.

We decided to see if we could create an evidence-based solution  developed with the patient in mind.  To do this our Oxford-based team created a ‘digital physiotherapist’,  which can be installed on a patient’s mobile phone device as an app called enRecover (enhancedRecovery),  that is free for patients to use via the NHS. We are working in conjunction with the Oxford Academic Health Science Network (AHSN) to build, test and implement this app as part of a system that benefits patients, clinicians and commissioners alike.

Research has also shown that patients who are actively monitored, given regular motivation, in addition to illustrative materials – will have better compliance and adherence with physiotherapy and improved health outcomes (6). Our mHealth device sends patients personalised push notification reminders for when they need to perform exercises. The material contains high-quality videos, which remind patients how to perform these exercises. The app also includes patient-specific advice for post-operative care after knee replacement. Data from the app can be fed back to clinicians who will monitor patient progress remotely. Later this year we will be running a randomised controlled trial to determine its efficacy compared with standard physiotherapy care after knee replacement.

At enRecover, we firmly believe mHealth physiotherapy solutions will improve outcomes for patients, create substantial savings to the NHS, and undoubtedly play a key role in the future of post-operative patient care.

The team can be contacted at

Conflicts of Interest. Authors Dr Navraj S Nagra and Maxime Cox are academics at the University of Oxford who are developing enRecover, an mHealth app offering post-operative physiotherapy support. enRecover will be running its first randomised controlled trial in 2018.

Dr Navraj S Nagra is Clinical Research Fellow at Oxford University Hospitals NHS Foundation Trust, a DPhil Candidate at the University of Oxford and Founder and CEO of enRecover Healthcare. He believes in using digital disruption to improve health equality and provision for patients.



Maxime Cox has a background in health consulting and is reading Medicine at the University of Oxford. As the Head of Technology and Innovation at enRecover Healthcare, he is leading product development to provide optimal value for the health economy and improve patient outcomes.



1. Carr AJ, Robertsson O, Graves S, et al. Knee replacement. Lancet. 2012;379(9823):1331-1340. doi:10.1016/S0140-6736(11)60752-6
2. National Joint Registry. 2017 14th Annual Report National Joint Registry for England, Wales, Northern Ireland and the Isle of Man. 2017. 14th Annual Report 2017.pdf. Accessed March 15, 2018.
3. Artz N, Elvers KT, Lowe CM, Sackley C, Jepson P, Beswick AD. Effectiveness of physiotherapy exercise following total knee replacement: systematic review and meta-analysis. BMC Musculoskelet Disord. 2015;16:15. doi:10.1186/s12891-015-0469-6
4. Dakin H, Gray A, Fitzpatrick R, Maclennan G, Murray D, KAT Trial Group TKT. Rationing of total knee replacement: a cost-effectiveness analysis on a large trial data set. BMJ Open. 2012;2(1):e000332. doi:10.1136/bmjopen-2011-000332
5. Chartered Society of Physiotherapy. Government accused of lacking a coherent strategy on physiotherapy workforce | The Chartered Society of Physiotherapy. Published 2017. Accessed March 15, 2018.
6. McLean SM, Burton M, Bradley L, Littlewood C. Interventions for enhancing adherence with physiotherapy: A systematic review. Man Ther. 2010;15(6):514-521. doi:10.1016/J.MATH.2010.05.012
7. Williams DP, O’Brien S, Doran E, et al. Early postoperative predictors of satisfaction following total knee arthroplasty. Knee. 2013;20(6):442-446. doi:10.1016/J.KNEE.2013.05.011
8. Kwasnicki RM, Ali R, Jordan SJ, et al. A wearable mobility assessment device for total knee replacement: A longitudinal feasibility study. Int J Surg. 2015;18:14-20. doi:10.1016/j.ijsu.2015.04.032
9. Negus JJ, Cawthorne DP, Chen JS, Scholes CJ, Parker DA, March LM. Patient outcomes using Wii-enhanced rehabilitation after total knee replacement – The TKR-POWER study. Contemp Clin Trials. 2015;40:47-53. doi:10.1016/J.CCT.2014.11.007

Using mother nature to inspire the next generation of medical implants and devices

by Dr. Gavin Hazell

Medical devices are ubiquitous in modern medicine. Devices range from simple catheters to artificial cardiac devices and complex materials that can replace our own joints. Contemporary surgical procedures have revolutionised our approach to joint replacement with 160, 000 total hip and knee replacement procedures performed each year in England and Wales. Medical implants have seen a rapid expansion in use which has been facilitated by technological advances and reduced manufacturing costs. Today, these devices profoundly impact patient quality of life and disease outcome.

However, all of these devices suffer from a major weakness. They are susceptible to bacterial colonisation, which leads to a medical device associated infection. Once bacteria adhere to the surface of an implant they grow and proliferate until a dense bacterial film resides on the surface, known as a biofilm. The presence of such a bacterial layer leads to the failure of the medical device and puts the patient at risk of sepsis and death.

Biofilms on the surface of implantable materials (such as a titanium hip replacement) are difficult to treat as they are generally recalcitrant to conventional antibiotic therapy. It is therefore necessary for the surgeon to remove the device, thoroughly clean the infected area and implant a replacement. This comes at a significant financial cost to the NHS as well as being a very traumatic and invasive experience for the patient.

Another significant problem with these kinds of infections is the presence of antibiotic resistant bacteria. If the infection is composed of bacteria such as methicillin-resistant Staphylococcus aureus (MRSA, or other antibiotic resistant strains), this makes it even harder to treat as conventional antibiotics cannot be used.

What is required for the next generation of medical implants/devices are materials with surfaces that are lethal to adherent bacterial cells. If surfaces that kill bacteria upon contact could be used in medical devices, then the risk of infections associated with these materials would be significantly reduced. This would negate the need for revision surgery, lower the financial burden for the healthcare provider and significantly improve patient experience.

Recently it has been shown that the surface of the wing of the cicada fly is composed of periodic arrays of nanopillars. These are tiny pillars that are around 200 nm in height and only visible with a very powerful microscope (human hair is around 100, 000 nm in width). When bacteria hit such surfaces, their cellular membrane stretches across these nanopillars and is placed under mechanical strain. If the membrane is soft enough, it ruptures and the bacteria die (see figure below).

In our laboratory, we seek such inspiration from nature to modify the surface of medical implants/devices and render them bactericidal. We generate surfaces composed of tiny nanospikes and/or nanocones that are able to mechanically kill bacteria. Killing bacteria through mechanical means ensures that they cannot evolve resistance and it is possible to kill bacteria that are already resistant to antibiotic strains.

We generate nanopatterns on a vast array of materials. We are currently focused on forming nanocones on polymers for use in catheters, blood storage bags and contact lenses. Black silicon is used as a new material for biosensor electrodes. Here we can pattern extremely sharp spikes that are able to puncture bacterial contaminants when the electrode is working. Finally, a large interest is in the patterning of titanium dioxide for use in prosthetic joint replacement surgery. It is possible to form nanospikes on these surfaces that can also puncture adherent bacteria. Below is an image gallery of all the materials we are working with along with some microscope images of dead, punctured bacteria on the surfaces. A note on intended clinical application is also included. (Please click on image to expand) 

Dr Gavin Hazell is a research scientist working in the biomaterials engineering group at the University of Bristol. He is an expert in materials science and his research interests lie in finding new ways to improve healthcare through the generation of novel, smart materials.