The hip is a ball and socket joint. When surgeons replace the joint they try to put the centre of the new hip replacement where the centre of the original one was. If this doesn’t happen this can leave the patient with one leg longer than the other. We are currently designing new instruments to help the surgeon replace the hip joint centre more accurately.

Although our survivorship following knee replacements 10 years post operation is excellent with over 98% of our patients still having their original knee our patient satisfaction is not as good. Unfortunately, one patient in twenty feels that not only has the operation not helped but they have more pain than before surgery. In October 2009 a focus group was set up and organised by BART. This involved leading experts from the UK who identified many possible causes of patient unhappiness. In May 2015 we held a further two day meeting to discuss ways of improving early outcomes following knee replacements. This meeting involved leading experts from the UK, South Africa, Israel, the Netherlands and Switzerland. As a result of this we are now doing collaborative research with the School of Psychology at Queen’s University Belfast looking at the use of pre-operative psychological questionnaires to see whether they can predict how well a patient will do following a knee replacement. This study is now fully recruited with 131 patients taking part who will be followed up for 1 year. If this is proven, in the future we would be able to predict who would be at risk of not doing well following a knee replacement and be able to intervene to improve their outcome.

As we carry out a great number of joint replacements it is important to look at our complications following surgery so that they can be kept to a minimum. This includes problems such as dislocations, infections, nerve injuries and on-going painful joints. These are continually audited and reported where necessary. Over a period of years we have been able to reduce the number of each of these complications due to our careful monitoring.

With an established Outcomes Unit within our unit we are able to monitor patient’s outcomes scores pre-operatively, and post-operatively at 6 weeks (for hips and partial knees only), 3 months (knees only) and then at 1 year. We can also do long term follow up of specific implants where necessary. This enables us to carry out on-going studies in relevant areas of joint replacement outcomes. It is important that centres such as ours report their long term follow up. Our team now have approval from the Research Ethics Committee to use all of this data, if anonymised, for R&D approved research purposes provided the patient has consented. One study carried out using this approval evaluated the influence of social deprivation on pre-operative disease severity and post-operative outcomes following joint replacement. We are also looking at the value of long-term review. This means the routine review of patients more than one year from surgery. It is our belief that with the modern implants we use it should be safe to discharge patients at one year if they have no problems. They would then have open access to come back and see us if they had problems.

This is a major problem. Work previously carried out by us some years ago confirmed the effectiveness of tranexamic acid in reducing blood loss but it was still not being used in routine practice. As well as having a direct beneficial effect on the patient as less blood is lost, it also significantly reduces the requirement for blood transfusions (a major issue for the patient and the NHS). A major study (TRAC-24) is now underway to determine if the use of oral tranexamic acid post-operatively for up to 24 hours will reduce blood loss at 48 hours for patients undergoing hip or knee replacements. This study is being funded by BART and the HSC Research & Development Division of the Public Health Agency. The Northern Ireland Clinical Trials Unit are assisting with the study and data management. A total of 1066 patients will be recruited into the study and we aim to be fully recruited by July 2018. While this study is still on-going, early results have led to a change in practice, with tranexamic acid now being used on all patients.

A jig to maintain knee flexion directly after knee replacements was developed within our unit to help reduce blood loss which is now used on all patients.

We have been involved in various studies looking at how long patients stay in hospital after their hip or knee replacement. Obviously a patient would never be discharged unless they were ready but the emphasis is that patients are going into hospital to get better and become independent and should be able to leave hospital in 2 days or less if they are medically fit. A recent study showed that 21% of patients stay longer than 3 days following operation and 43% of bed days are used by these patients. This is a major drain on hospital resources. We are looking at ways to reduce this, for example improved pre-operative patient education and trying to make arrangements for people that need help when they go home before they come in to hospital.

As Musgrave Park Hospital carries out a high volume of operations every year it is important we review these patients so we can monitor outcomes and find trends in certain types of implant. We carry out approved clinical trials of new hip or knee components. We also closely follow up those patients with newer types of implant. We also follow up patients with specific hip or knee replacement over a long period of time, for example, at the moment we are doing a ten year review of the Oxford® partial knee replacement, a 10 year review of the Corail® femoral stem used in hip replacements and a 20 year review of the LCS® Complete knee replacement. We are also involved in a clinical trial called “TOPKAT” comparing the partial knee replacement to a total knee replacement which is run by Oxford University. The aim of this study is to see whether the early outcomes in terms of patient satisfaction at 6 weeks and 1 year in the partial knee replacement population is different compared to the total knee replacement population at 3 months and 1 year.

One common cause of patient unhappiness following a hip replacement is a difference in leg length. We have done research looking at what level of difference a patient is aware of and it is a lot less that we thought. This has given the surgeons working here a greater appreciation of the importance of replacing the hip joint as closely as possible to the original joint centre. We are also looking at more accurate methods of measuring leg length discrepancies on X-ray.

We have completed various studies over the years looking at how patients walk after their hip or knee replacement. This is all done in the Gait Laboratory in Musgrave Park Hospital.

As obesity becomes more widespread in the developed world more obese patients will need orthopaedic surgery, in particular knee replacements. This is a costly problem for the NHS. We have a particular interest in this area and have published on the intra-operative and short term outcomes in morbidly obese hip replacement patients and will continue to investigate this area.

It is important to audit our practice to make sure we are giving patients the best care possible and to identify areas that need to be improved. We continuously audit our patient complications and outcomes up until 90 days after a patient’s operation. In addition to this we carry out specific audits in areas we think need reviewed. Examples of this would be looking at the amount a blood loss a patient has, whether patients hip replacement’s ‘squeak’, how long patients stay in hospital, what positions the patient’s implants are inserted. The largest audit carried out was an audit of 1000 consecutive hip and knee replacements. The audit follows 1000 joints from pre-op to 3 months post op and reports on recovery and complications.

In November 2013 N. Ireland joined the National Joint Registry which collects information on joint replacement operations. This is to monitor the performance of implants and the effectiveness of different types of surgery. For more information on the National Joint registry go to: www.njrcentre.org.uk.

For the last few years one of our young doctors has been researching the factors that contribute to confusion after an operation. This is a major and very common problem. This has resulted in a successful PhD as well as publications and the work continues in this area.

This refers to the risk of clots following surgery. Such clots can occur in the legs when they are called deep vein thromboses (DVTs) or in the lungs when they are called pulmonary emboli (PEs). There are now many drugs that help to reduce the risk of clots but many such drugs can increase the risk of bleeding. We have been doing a lot of work to look at the effectiveness of just using Aspirin, which carries a lower risk of bleeding.

When a patient is having their hip replaced during the operation they are either lying on their back or on their side. In Musgrave Park Hospital and in over 90% of the hospitals around the world, patients lie on their side. Our research has shown that to make sure the new hip is implanted correctly the surgeon needs to position the patient very carefully. We are now working on methods of holding patients in the perfect position when lying on their side.