title: No effect of obesity on limb and component alignment after computer-assisted total knee arthroplasty.
abstract: OBJECTIVE
  This retrospective study aimed to determine if computer navigation provides consistent accuracy for limb and component alignment during TKA irrespective of body mass index (BMI) by comparing limb and component alignment and the outlier rates in obese versus non-obese individuals undergoing computer-assisted TKA.
  
  
  METHODS
  Six hundred and thirty-five computer assisted total knee arthroplasties (TKAs) performed in non-obese individuals (BMI<30 kg/m(2)) were compared with 520 computer-assisted TKAs in obese individuals (BMI ≥ 30 kg/m(2)) for postoperative limb and component alignment using full length standing hip-to-ankle radiographs.
  
  
  RESULTS
  No significant difference in postoperative limb alignment (179.7° ± 1.7° vs 179.6° ± 1.8°), coronal femoral (90.2° ± 1.6° vs 89.8° ± 1.9°) and tibial component (90.2° ± 1.6° vs 90.3° ± 1.7°) alignment and outlier rates (6.2% vs 7.5%) was found between non-obese and obese individuals. Similarly, alignment and the outlier rates were similar when non-obese individuals and a subgroup of morbidly obese individuals (BMI >40 kg/m(2)) were compared.
  
  
  CONCLUSIONS
  Computer navigation can achieve excellent limb and component alignment irrespective of a patient's BMI. Although obesity may not be an indication per se for using computer navigation during TKA, it will help achieve consistently accurate limb and component alignment in obese patients.
  
  
  METHODS
  Level II.
authors.affiliation: Department of Orthopaedic Surgery, Breach Candy Hospital, Mumbai, India. Electronic address: gautams10@gmail.com.
authors.forename: Gautam M
authors.initials: GM
authors.lastname: Shetty
authors.affiliation: Department of Orthopaedic Surgery, Breach Candy Hospital, Mumbai, India.
authors.forename: Arun B
authors.initials: AB
authors.lastname: Mullaji
authors.affiliation: Department of Orthopaedic Surgery, Breach Candy Hospital, Mumbai, India.
authors.forename: Sagar
authors.initials: S
authors.lastname: Bhayde
authors.affiliation: Department of Orthopaedic Surgery, Breach Candy Hospital, Mumbai, India.
authors.forename: A P
authors.initials: AP
authors.lastname: Lingaraju
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D015992:Body Mass Index; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology; D020370:Osteoarthritis, Knee / Q000453:epidemiology / Q000601:surgery; D011859:Radiography; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted; D016896:Treatment Outcome
keywords: Alignment; Computer-assisted surgery; Knee; Obesity; Total knee arthroplasty