title: Lateral unicompartmental knee replacement for the treatment of arthritis progression after medial unicompartmental replacement.
abstract: OBJECTIVE
  Lateral progression of arthritis following medial unicompartmental knee arthroplasty (UKA), although infrequent, is still the most common reason for revision surgery. Treatment options normally include conversion to total knee arthroplasty. An alternative strategy for some patients may be addition of a lateral UKA. We report the first results of staged bi-compartmental UKA (Bi-UKA) strategy.
  
  
  METHODS
  We retrospectively selected from our UKA database patients who underwent a lateral UKA to treat a symptomatic lateral osteoarthritis progression after a medial UKA. The analysis included a clinical and radiological assessment of each patient.
  
  
  RESULTS
  Twenty-five patients for a total of 27 knees of staged Bi-UKA were carried out in a single centre. The mean time interval between primary medial UKA and the subsequent lateral UKA was 8.1 years (SD ± 4.6 years). The mean age at the time of the Bi-UKA was 77.1 years (SD ± 6.5 years). The median hospital stay was 3 (range 2-9 days) days, and the mean follow-up after Bi-UKA was 4 years (SD ± 1.9 years). The functional scores showed a significant improvement as compared to the pre-operative status (paired t test, p = 0.003). There were no radiological evidences of failure. None of the patients needed blood transfusion, and there was no significant complications related to the surgical procedure without further surgeries or revisions at final follow-up.
  
  
  CONCLUSIONS
  These results suggest that addition of a lateral UKA for arthritis progression following medial UKA is a good option in appropriately selected patients.
  
  
  METHODS
  Observational study without controls, Level IV.
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Oxford, UK. hemant.pandit@ndorms.ox.ac.uk.
authors.forename: H
authors.initials: H
authors.lastname: Pandit
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Oxford, UK.|Orthopaedics and Traumatology Unit, "Santa Maria della Misericordia" University Hospital, Udine, UD, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Mancuso
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Oxford, UK.
authors.forename: C
authors.initials: C
authors.lastname: Jenkins
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Oxford, UK.
authors.forename: W F M
authors.initials: WFM
authors.lastname: Jackson
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Oxford, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Price
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Oxford, UK.
authors.forename: C A F
authors.initials: CAF
authors.lastname: Dodd
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Oxford, UK.
authors.forename: D W
authors.initials: DW
authors.lastname: Murray
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D016208:Databases, Factual; D018450:Disease Progression; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000601:surgery; D007720:Knee Prosthesis; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D018579:Patient Selection; D011859:Radiography; D016059:Range of Motion, Articular; D012086:Reoperation / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: Arthroplasty; Lateral arthritis progression; Medial unicompartmental knee arthroplasty; Staged bi-unicompartmental knee arthroplasty