Outcomes

Definition

The World Health Organisation defines an outcome measure as a “change in the health of an individual, group of people, or population that is attributable to an intervention or series of interventions.” Outcome measures include such elements as change in ability to undertake activities, patient satisfaction, readmission to hospital, clinical complications and mortality.

The first National Joint Registry

The first Orthopaedic, National Joint registry to monitor the outcomes of joint replacements and find out how long the implants lasted was established, in Sweden, for knee replacements, in 1975. The Swedish Hip Arthroplasty Register was started in 1979 and over the past four decades the Swedish registries have provided valuable information on how long joint replacements last, how well different implants perform, how results are affected by the type of implant that was used, the problem that led to the joint replacement being undertaken, the general health of the patients, their gender and age. The registries have also shown how these outcomes have improved over time. The graphs shown in the adjacent column were published in the 2015 Swedish registry and all the annual reports dating back to 2002 can be accessed at https://shpr.registercentrum.se/in-english/annual-reports/p/rkeyyeElz .

Evidence from the Australian National Joint Registry

In many countries, the Direct Anterior approach has gained increasing popularity in recent years. In Australia, just over a quarter of all hip replacements are now undertaken by this technique and over 50,000 Anterior hip replacements are being tracked by the Australian Registry https://aoanjrr.sahmri.com/home. This has enabled the Australian Registry to report on the outcome of hip replacement undertaken by different approaches. Over the first four years, the overall revision (redo) rates of Anterior, Lateral and Posterior approach hip replacements are almost identical. However, when failures do occur, the reasons are slightly different.

Anterior approach hip replacements are more likely to require revision during the first three months for fractures around the implants and over the first four years for component loosening.

Over the first four years, Posterior and Lateral approach hips are more likely to require revision for infection and for dislocation.

Evidence from the UK National Joint Registry

The UK National Joint Registry (NJR) https://www.njrcentre.org.uk was established in 2002 and now contains information on over 3 million hip, knee and other joint replacements. It is the largest joint replacement registry in the world and also collects data on patient reported outcome measures (PROMS). The NJR provides surgeons with feedback on how they are performing and helps them to identify areas in which they may be able to improve their practice. The NJR has identified that six months after a hip replacement, approximately 86% of patients feel that their problem is much better than before their operation but about 2% are either a little, or much worse than they were before their operation. Just over 90% of patients rate the result of their hip replacement as good, very good or excellent but, about 2% of patients rate the result of their operation as poor.

The 2% of patients whose hip replacements turn out badly probably represent the small number who suffer a complication such as an infection getting into the joint, the joint dislocating and becoming unstable, a break of the bone around one of the components, failure of implant fixation or one of the many other problems that can beset such surgery. These problems can usually be resolved but the treatment is often protracted and upsetting for all involved.