title: Oxford unicompartmental knee arthroplasty: medial pain and functional outcome in the medium term.
abstract: BACKGROUND
  In our experience results of the Oxford unicompartmental knee replacement have not been as good as had been expected. A common post operative complaint is of persistent medial knee discomfort, it is not clear why this phenomenon occurs and we have attempted to address this in our study.
  
  
  METHODS
  48 patients were retrospectively identified at a mean of 4.5 years (range = 3 to 6 years) following consecutive Oxford medial Unicompartmental Knee arthroplasties for varus anteromedial osteoarthritis. The mean age at implantation was 67 years (range 57-86). Of these 48 patients, 4 had died, 4 had undergone revision of their unicompartmental knee replacements and 2 had been lost to follow up leaving 38 patients with 40 replaced knees available for analysis using the 'new Oxford Knee Score' questionnaire. During assessment patients were asked specifically whether or not they still experienced medial knee discomfort or pain.
  
  
  RESULTS
  The mean 'Oxford score' was only 32.7 (range = 16 to 48) and 22 of the 40 knees were uncomfortable or painful medially.The accuracy of component positioning was recorded, using standard post operative xrays, by summing the angulation or displacement of each component in two planes from the ideal position (according to the 'Oxford knee system radiographic criteria'). No correlation was demonstrated between the radiographic scores and the 'Oxford scores', or with the presence or absence of medial knee discomfort or pain.
  
  
  CONCLUSIONS
  In our hands the functional outcome following Oxford Unicompartmental knee replacement was variable, with a high incidence of medial knee discomfort which did not correlate with the postoperative radiographic scores, pre-op arthritis and positioning of the prosthesis.
authors: Kent and Sussex Hospital, Mount Ephraim Rd, Tunbridge Wells, Kent, TN4 8AT, UK. drmedmondson@hotmail.com
authors: Mark C
authors: MC
authors: Edmondson
authors: David
authors: D
authors: Isaac
authors: Malin
authors: M
authors: Wijeratna
authors: Sean
authors: S
authors: Brink
authors: Paul
authors: P
authors: Gibb
authors: Paul
authors: P
authors: Skinner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018771:Arthralgia / Q000000981:diagnostic imaging / Q000209:etiology*; D019645:Arthroplasty, Replacement, Knee / Q000379:methods; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D007720:Knee Prosthesis; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D010149:Postoperative Pain / Q000000981:diagnostic imaging; D017060:Patient Satisfaction; D011859:Radiography; D020127:Recovery of Function; D012189:Retrospective Studies; D016896:Treatment Outcome