title: Minimally invasive Oxford medial unicompartmental knee arthroplasty in young patients.
abstract: OBJECTIVE
  Advanced knee arthritis in young patients is a challenging problem that may necessitate surgical treatment. There are few published studies of mobile-bearing unicompartmental knee arthroplasty (UKA) in young patients, while indications have expanded to its use in this demanding patient group.
  
  
  METHODS
  The clinical and radiographic results of the first 118 consecutive Oxford medial UKAs (OUKA) using a minimally invasive technique (phase 3) in 101 patients 60 years of age or younger at the time of surgery were evaluated. Median age at surgery was 57 (25-60) years. Kaplan-Meier survivorship analysis was used to estimate implant survival.
  
  
  RESULTS
  Mean time of follow-up evaluation was five (SD 1.6) years. At final follow-up, three patients (three knees) had died, and two patients (three knees) were lost to follow-up. Five knees were revised: three for unexplained pain, one for early infection and one for bearing fracture. There was one impending revision for progression of osteoarthritis in the lateral compartment. The radiographic review demonstrated that 5 % of the knees had progressive arthritis in the lateral knee compartment, of those 2 % with full joint space loss and pain. The Kaplan-Meier survival analysis, using revision for any reason as the endpoint, estimated the five-year survival rate at 97 % (95 % CI 91-99). Ninety-six per cent of the non-revised patients were satisfied with the outcome, and 4 % were dissatisfied. The mean Oxford knee score was 41 (SD 7), with 6 % of the knees having a poor result. The mean AKSS was 89 (SD 14), mean flexion was 129° (SD 13) and the mean UCLA score was 6.8 (SD 1.5).
  
  
  CONCLUSIONS
  Minimally invasive Oxford medial UKA was reliable and effective in this young and active patient cohort providing high patient satisfaction at mid-term follow-up. Progressive arthritis in the lateral knee compartment was a relevant failure mode in this age group. Most revisions were performed for unexplained pain, while we did not find loosening or wear in any patient.
  
  
  METHODS
  IV.
authors.affiliation: Department of Orthopaedic and Trauma Surgery, University of Heidelberg, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany.
authors.forename: Marcus R
authors.initials: MR
authors.lastname: Streit
authors.affiliation: Department of Orthopaedic and Trauma Surgery, University of Heidelberg, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany.|BG Trauma Center Ludwigshafen, Ludwig-Guttmann-Strasse 13, 67071, Ludwigshafen am Rhein, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Streit
authors.affiliation: Department of Orthopaedic and Trauma Surgery, University of Heidelberg, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany.
authors.forename: Tilman
authors.initials: T
authors.lastname: Walker
authors.affiliation: Institute of Medical Biometry and Informatics, University of Heidelberg, Im Neuenheimer Feld 305, 69120, Heidelberg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bruckner
authors.affiliation: Department of Orthopaedic and Trauma Surgery, University of Heidelberg, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Philippe Kretzer
authors.affiliation: Department of Orthopaedic and Trauma Surgery, University of Heidelberg, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Ewerbeck
authors.affiliation: Department of Orthopaedic and Trauma Surgery, University of Heidelberg, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Merle
authors.affiliation: Department of Orthopaedic and Trauma Surgery, Orthopädische Klinik Paulinenhilfe, Diakonieklinikum, Rosenbergstrasse 38, 70192, Stuttgart, Germany.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Aldinger
authors.affiliation: Department of Orthopaedic and Trauma Surgery, University of Heidelberg, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany. tobias.gotterbarm@med.uni-heidelberg.de.
authors.forename: Tobias
authors.initials: T
authors.lastname: Gotterbarm
mesh_terms: D000328:Adult; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D018450:Disease Progression; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007719:Knee Joint / Q000601:surgery; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D020370:Osteoarthritis, Knee / Q000601:surgery*; D017060:Patient Satisfaction; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: Active patients; Medial UKA; Mobile-bearing UKA; Oxford UKA; UKR; Unicompartmental knee arthroplasty; Young patients