Weight Gain After Primary Total Knee Arthroplasty Is Associated With Accelerated Time to Revision for Aseptic Loosening.
Obesity is a major health problem worldwide and is associated with complications after total knee arthroplasty (TKA). It remains unknown whether a change in body mass index (BMI) after primary TKA affects the reasons for revision TKA or the time to revision TKA.



A total of 160 primary TKAs referred to an academic tertiary center for revision TKA were retrospectively stratified according to change in BMI from the time of their primary TKA to revision TKA. The association between change in BMI and time to revision was also analyzed according to indication for revision of TKA using Pearson's chi-square test.



The mean change in BMI from primary to revision TKA was 0.82 ± 3.5 kg/m2. Maintaining a stable weight after primary TKA was protective against late revision TKA for any reason (P = .004). Patients who failed to reduce their BMI were revised for aseptic loosening earlier, at less than 5 years (P = .020), whereas those who reduced their BMI were revised later, at over 10 years (P = .004).



Maintaining weight after primary TKA is protective against later revision TKA for any reason but failure to reduce weight after primary TKA is a risk factor for early revision TKA for aseptic loosening and osteolysis. Orthopedic surgeons should recommend against weight gain after primary TKA to reduce the risk of an earlier revision TKA in the event that a revision TKA is indicated.
Department of Orthopaedic Surgery, Stanford University, Stanford, California; Department of Orthopaedic Surgery, Stanford University School of Medicine, Redwood City, California; Department of Orthopaedic Surgery, National University Hospital, Singapore.
Chin Tat
CT
Lim
Department of Orthopaedic Surgery, Stanford University, Stanford, California; Department of Orthopaedic Surgery, Stanford University School of Medicine, Redwood City, California.
Stuart B
SB
Goodman
Department of Orthopaedic Surgery, Stanford University, Stanford, California; Department of Orthopaedic Surgery, Stanford University School of Medicine, Redwood City, California.
James I
JI
Huddleston
Department of Orthopaedic Surgery, Stanford University, Stanford, California; Department of Orthopaedic Surgery, Stanford University School of Medicine, Redwood City, California.
Alex H S
AHS
Harris
Department of Orthopaedic Surgery, Stanford University, Stanford, California; Department of Orthopaedic Surgery, Stanford University School of Medicine, Redwood City, California.
Subhrojyoti
S
Bhowmick
Department of Orthopaedic Surgery, Stanford University, Stanford, California; Department of Orthopaedic Surgery, Stanford University School of Medicine, Redwood City, California.
William J
WJ
Maloney
Department of Orthopaedic Surgery, Stanford University, Stanford, California; Department of Orthopaedic Surgery, Stanford University School of Medicine, Redwood City, California.
Derek F
DF
Amanatullah
D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000706:statistics & numerical data*; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D010014:Osteolysis; D011475:Prosthesis Failure / Q000209:etiology*; D012086:Reoperation / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012307:Risk Factors; D015430:Weight Gain
BMI; obesity; revision knee arthroplasty; total knee arthroplasty; weight change