title: Lateral osteophytes do not represent a contraindication to medial unicompartmental knee arthroplasty: a 15-year follow-up.
abstract: OBJECTIVE
  Lateral osteophytes have been reported to be associated with lateral compartment disease and as such it is unclear whether medial unicompartmental knee arthroplasty should be performed if these are present.
  
  
  METHODS
  Using the OARSI classification system, 0 (no osteophyte) to 3 (large osteophyte), radiographs from a series of cemented meniscal-bearing unicompartmental knee arthroplasty implanted in the setting of full-thickness lateral cartilage where lateral osteophytes were not considered a contraindication were identified and factors associated with the presence and size of lateral osteophytes, and their impact on clinical outcomes and implant survival were assessed.
  
  
  RESULTS
  Pre-operative radiographs from 458 knees (392 patients), independently followed up for a mean 10.5 years (range 5.3-16.6), were assessed. Lateral osteophytes were present in 62 % of knees with 18 % scored as Grade 3. Inter-observer reliability was good (kappa = 0.70). The presence and size of lateral osteophytes was associated with younger age at joint replacement (p = 0.01) and increasing BMI (p = 0.01). No association was seen with gender, pre-operative status, assessed using the Oxford Knee Score (OKS), American Knee Society (AKSS) Objective or Functional Score, Tegner activity score, or size of medial tibial lesion. Subgroup analysis of Grade 3 Osteophytes revealed that these were associated with a greater degree of macroscopic ACL damage. At 10 years there was no difference in function (n.s.), and at 15 years no difference in implant survival or mechanism of failure between groups (n.s.). Subgroup analysis of Grade 3 osteophytes found no significant difference in functional outcome at 10 years or implant survival at 15 years.
  
  
  CONCLUSIONS
  The presence of lateral osteophytes is not a contraindication to medial meniscal-bearing unicompartmental knee arthroplasty. The clinical relevance of this study is that it highlights the importance of an appropriate pre-operative assessment of the lateral compartment as in the setting of full-thickness cartilage at operation lateral osteophytes do not compromise long-term functional outcome or implant survival.
  
  
  METHODS
  IV.
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences, Botnar Research Centre, Nuffield Orthopaedic Centre, Windmill Road, Oxford, OX3 7LD, UK. thomas.hamilton@ndorms.ox.ac.uk.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Hamilton
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences, Botnar Research Centre, Nuffield Orthopaedic Centre, Windmill Road, Oxford, OX3 7LD, UK.
authors.forename: Rajan
authors.initials: R
authors.lastname: Choudhary
authors.affiliation: Nuffield Orthopaedic Centre, Oxford University Hospitals NHS Foundation Trust, Windmill Road, Oxford, OX3 7LD, UK.
authors.forename: Cathy
authors.initials: C
authors.lastname: Jenkins
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences, Botnar Research Centre, Nuffield Orthopaedic Centre, Windmill Road, Oxford, OX3 7LD, UK.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Mellon
authors.affiliation: Nuffield Orthopaedic Centre, Oxford University Hospitals NHS Foundation Trust, Windmill Road, Oxford, OX3 7LD, UK.
authors.forename: Christopher A F
authors.initials: CAF
authors.lastname: Dodd
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences, Botnar Research Centre, Nuffield Orthopaedic Centre, Windmill Road, Oxford, OX3 7LD, UK.|Nuffield Orthopaedic Centre, Oxford University Hospitals NHS Foundation Trust, Windmill Road, Oxford, OX3 7LD, UK.
authors.forename: David W
authors.initials: DW
authors.lastname: Murray
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Sciences, Botnar Research Centre, Nuffield Orthopaedic Centre, Windmill Road, Oxford, OX3 7LD, UK.|Nuffield Orthopaedic Centre, Oxford University Hospitals NHS Foundation Trust, Windmill Road, Oxford, OX3 7LD, UK.
authors.forename: Hemant G
authors.initials: HG
authors.lastname: Pandit
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D002356:Cartilage; D000075202:Contraindications; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D065466:Lysholm Knee Score; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D054850:Osteophyte / Q000150:complications / Q000000981:diagnostic imaging*; D011859:Radiography; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery; D016896:Treatment Outcome
keywords: Functional outcome; Implant survival; Meniscal-bearing unicompartmental knee arthroplasty; Osteophytes; Patient selection