Are pain and function better measures of outcome than revision rates after TKR in the younger patient? A.J. Price ⁎, D. Longino, J. Rees, R. Rout, H. Pandit, K. Javaid, N. Arden, C. Cooper, A.J. Carr, C.A.F. Dodd, D.W. Murray, D.J. Beard The Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, NIHR Biomedical Research Unit, The Nuffield Orthopaedic Centre NHS Trust, Oxford, UK abstract article info Article history: Received 10 June 2009 Received in revised form 11 September 2009 Accepted 14 September 2009 Keywords: Knee Arthroplasty Survival Outcome Young age Revision is the gold standard outcome measurement for survival analyses of orthopaedic implants but reliance on revision as an endpoint has been recently questioned. This study, that assesses long-term outcome in a specific group of patients who had undergone total knee replacement (TKR) for osteoarthritis, highlights the main problems facing modern survival analyses. Minimum 12-year survival and outcome data were reviewed for a series of sixty patients under the age of 60 years (mean age 55.4 years) who underwent total knee replacement (TKR) for osteoarthritis. The patients are a subgroup from a larger consecutive series of 1429 patients who underwent TKR between 1987 and 1993 at a single institution. Whilst the main study aim was to compare outcome of TKR using different endpoints, the outcome of TKR in this younger subpopulation could also be investigated. With revision as the primary endpoint the survival for TKR was 82.2% (95% CI 17.3). The mean OKS at follow- up (mean 15.7 years) was 30.9. However, many of the 82% of patients who did not undergo revision had a less than satisfactory outcome. 41% of these patients reported modest or severe pain (using the OKS) at final follow-up. A combined endpoint including revision, poor function and significant pain drastically reduced the survival rate for the operation. Survival based on revision alone provides an acceptable but inaccurate impression of outcome in younger TKR patients (under 60 years). A true representation of the success of TKR should include pain and function as endpoints. © 2009 Published by Elsevier B.V. 1. Introduction The results of arthroplasty have traditionally been reported using survivorship analysis, with implant revision as the primary endpoint [1]. Given that the primary indication for TKR is severe pain, it has been suggested that pain (or even functional deficiency), represents a more appropriate outcome measure for treatment success following TKR [2]. Pain has the highest correlation with patient satisfaction of all variables studied following total hip arthroplasty [3,4]. Function, performance and activity levels are also accepted as valid markers of treatment success and may be more appropriate for the younger population [5,6]. The use of revision alone to indicate success or failure of a treatment such as TKR may well introduce bias in favour of the success. Namely, some patients, whilst unable or unwilling to undergo revision, would fail on the basis of a different classification system i.e. pain. Young total knee replacement patients provide a useful population from which to study this issue of appropriate outcome markers. In addition to the methodological issue, the work can also give some further insight into whether patients under 60 years should undergo TKR. Total knee replacement (TKR) is often used to treat late stage arthritic disease of the knee and is clearly established as a successful intervention for patients in the later stages of life [7–12]. In contrast, the long-term results for TKR in the younger population are less well defined. Some studies citing individual surgeons' case series have reported favourable mid- to long-term results in young non- rheumatoid patients, often on a par with those consistently reported in a more elderly demographic [13–16]. However there is some evidence that this group may have an increased incidence of premature loosening and failure [17] and this has been supported by the results from some large community and national joint registries [8,18–22]. It is of particular concern as the prevalence of arthritic disease in the young individual is likely to increase [23]. The classification of “young” is somewhat arbitrary and some authorities might argue that patients under 50 years represent the young TKR population. For this study it was felt that patients under 60 years still represented a younger population (pre-retirement) although the term “younger” is preferred and used throughout for this study. The purpose of this study was two-fold. Firstly, the study investigated whether the results and interpretation changed if patient reported The Knee 17 (2010) 196–199 ⁎ Corresponding author. Nuffield Department of Orthopaedic Surgery, Nuffield Orthopaedic Centre, Headington, Oxford, OX2 7LD, UK. Tel.: +44 1865 737539; fax: +44 1865 737641. E-mail address: andrew.price@ndorms.ox.ac.uk (A.J. Price). 0968-0160/$ – see front matter © 2009 Published by Elsevier B.V. doi:10.1016/j.knee.2009.09.003 Contents lists available at ScienceDirect The Knee