title: Making the Oxford Hip and Knee Scores meaningful at the patient level through normative scoring and registry data.
abstract: OBJECTIVE
  The Oxford Hip and Knee Scores (OHS, OKS) have been demonstrated to vary according to age and gender, making it difficult to compare results in cohorts with different demographics. The aim of this paper was to calculate reference values for different patient groups and highlight the concept of normative reference data to contextualise an individual's outcome.
  
  
  METHODS
  We accessed prospectively collected OHS and OKS data for patients undergoing lower limb joint arthroplasty at a single orthopaedic teaching hospital during a five-year period. T-scores were calculated based on the OHS and OKS distributions.
  
  
  RESULTS
  Data were obtained from 3203 total hip arthroplasty (THA) patients and 2742 total knee arthroplasty (TKA) patients. The mean age of the patient was 68.0 years (sd 11.3, 58.4% women) in the THA group and in 70.2 (sd 9.4; 57.5% women) in the TKA group. T-scores were calculated for age and gender subgroups by operation. Different T-score thresholds are seen at different time points pre and post surgery. Values are further stratified by operation (THA/TKA) age and gender.
  
  
  CONCLUSIONS
  Normative data interpretation requires a fundamental shift in the thinking as to the use of the Oxford Scores. Instead of reporting actual score points, the patient is rated by their relative position within the group of all patients undergoing the same procedure. It is proposed that this form of transformation is beneficial (a) for more appropriately comparing different patient cohorts and (b) informing an individual patient how they are progressing compared with others of their age and gender. Cite this article: Bone Joint Res 2015;4:137-144.
authors: University of Edinburgh, FU413, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH164SB, UK.
authors: D F
authors: DF
authors: Hamilton
authors: The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
authors: J M
authors: JM
authors: Giesinger
authors: University of Edinburgh, FU413, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH164SB, UK.
authors: J T
authors: JT
authors: Patton
authors: University of Edinburgh, FU413, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH164SB, UK.
authors: D J
authors: DJ
authors: MacDonald
authors: University of Edinburgh, FU413, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH164SB, UK.
authors: A H R W
authors: AH
authors: Simpson
authors: University of Edinburgh, FU413, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH164SB, UK.
authors: C R
authors: CR
authors: Howie
authors: Kantonsspital St. Gallen, Rorschacherstrasse 95, CH- 9000 St. Gallen, Switzerland.
authors: K
authors: K
authors: Giesinger
keywords: Outcomes; PROMs; population models; Oxford Hip Score; Oxford Knee Score