title: Does activity affect the outcome of the Oxford unicompartmental knee replacement?
abstract: BACKGROUND
  High levels of activity are considered to be a contraindication to unicompartmental knee replacement (UKR) and are not recommended after UKR. To determine if these recommendations should apply to the mobile-bearing Oxford UKR, this study assessed the effect of post-operative activity level on the outcome of this device.
  
  
  METHODS
  The outcome of the first 1000 Phase 3 cemented Oxford UKRs implanted between 1998 and 2010 was assessed using survival analysis, the Oxford Knee Score (OKS) and the American Knee Society Objective (KSS-O) and Functional (KSS-F) Scores. Patients were grouped according to the maximum post-operative Tegner Activity Score.
  
  
  RESULTS
  The mean follow-up was 6.1 years (range 1 to 14). Overall, increasing activity was associated with superior survival (p=0.025). In the high activity group, with Tegner≥5 (n=115) 2.6% were revised and the 12-year survival was 97.3% (confidence interval (CI): 92.0% to 99.1%). In the low activity group, with Tegner≤4, (n=885) 4.3% were revised and the 12-year survival was 94.0% (CI: 91.4 to 95.8). The difference between the two groups was not significant (p=0.44). Although the final OKS and KSS-F were significantly better in the high activity group compared to the low activity group (OKS 45v40, KSS-F 95v78), there was no difference in the change in OKS or KSS-O.
  
  
  CONCLUSIONS
  High activity does not compromise the outcome of the Oxford UKR and may improve it. Activity should not be restricted nor considered to be a contraindication.
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom.
authors.forename: Adam M
authors.initials: AM
authors.lastname: Ali
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom; Nuffield Orthopaedic Centre, Oxford, United Kingdom.
authors.forename: Hemant
authors.initials: H
authors.lastname: Pandit
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom.
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Liddle
authors.affiliation: Nuffield Orthopaedic Centre, Oxford, United Kingdom.
authors.forename: Cathy
authors.initials: C
authors.lastname: Jenkins
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom.
authors.forename: Stephen
authors.initials: S
authors.lastname: Mellon
authors.affiliation: Nuffield Orthopaedic Centre, Oxford, United Kingdom.
authors.forename: Christopher A F
authors.initials: CA
authors.lastname: Dodd
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom; Nuffield Orthopaedic Centre, Oxford, United Kingdom. Electronic address: david.murray@ndorms.ox.ac.uk.
authors.forename: David W
authors.initials: DW
authors.lastname: Murray
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D005544:Forecasting; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D011474:Prosthesis Design; D016059:Range of Motion, Articular / Q000502:physiology*; D016896:Treatment Outcome
keywords: Activity level; Unicompartmental knee arthroplasty