Effect of Obesity on Component Alignment in Total Knee Arthroplasty

Abstract

Background: Obesity is routinely cited as a negative predictive factor for outcomes after total knee arthroplasty (TKA), but the direct mechanism responsible for this relationship has not been described. One possible explanation is a propensity for component malalignment in obese patients that is attributable to difficulty with surgical exposure. Methods: This study evaluated the effect of obesity on TKA component alignment in 251 primary TKAs during a 12-month period at a single center in 2009. Postoperative component alignment was retrospectively measured and compared between patients defined as obese (body mass index [BMI] ≥30 kg/m 2) and patients defined as nonobese (BMI <30 kg/m 2). Alignment was determined by measuring the coronal tibiofemoral angle, coronal femoral component angle, coronal tibial component angle, sagittal femoral component angle, and sagittal tibial component angle in all of the study patients. Results: Statistical analysis failed to demonstrate a statistically significant relationship between obesity and component alignment in any of the measured parameters. Conclusion: The results of this study support that obesity does not negatively affect TKA component alignment; another factor must be associated with the worse outcomes in obese patients undergoing TKA.

Greater risk of all‐cause revisions and complications for obese patients in 3 106 381 total knee arthroplasties: a meta‐analysis and systematic review

“…This study demonstrated that obese and morbidly obese patients were younger at time of index TKA, possibly due to earlier onset and accelerated progression of osteoarthritis 4,15,17,39,55,59,60,66,71,82,87 . This is likely to be contributed by increased stresses acting on the articular surfaces secondary to higher body weight, leading to osteoarthritis development 2 .…”

“…One additional article was identified from citation search and 210 full‐text articles were assessed for eligibility. Finally, 91 studies were included, with 22 prospective, 4,7,8,16,22–39 54 retrospective, 6,9–12,14,15,17,40–85 and 15 case‐controlled studies 5,13,18,19,86–96 …”

“…Eleven studies 4,15,17,39,55,59,60,66,71,82,87 reported a significantly younger patient cohort in the obese than non‐obese group ( p < 0.05). Meta‐analysis revealed obese and morbidly obese patients were 3.79 years (95% CI: 2.57–5.00, p < 0.0001, obese n = 4537, non‐obese n = 5448) and 6.79 years (95% CI: 5.78–7.81, p < 0.0001, morbidly obese n = 15 606, non‐obese n = 40 173) younger than non‐obese patients at index TKA (Supplement 2.1 2.2).…”

“…This increases external validity and applicability to the general population 97 . Although there has been a recent analysis by Chaudhry, 98 this was performed with articles only until August 2016 and, since then, there have been several high statistically powered studies published, of which some had varying conclusions 11,12,23,25,28,34,39,44,47,51,58,59,71,75,77,82,85 . Furthermore, Chaudhry 98 only focused on all‐cause, aseptic and septic revision risks and did not investigate other complications and peri‐operative parameters.…”

No influence of obesity on mid-term clinical, functional, and radiological results after computer-navigated total knee arthroplasty using a gap balancing technique

“…While some authors have reported greater risk for limb malalignment in TKAs when performed in the obese, 1,2 others have shown no increase in risk for mal-alignment in the obese patients undergoing TKA. 3,4 Similarly, some studies have showed comparable clinical and functional results between obese and non-obese patients 4e6 and others have concluded obesity to have a negative influence on the clinical and functional outcome after TKA. 7e9 Over the years, studies have established the superiority of computer-assisted TKA in achieving the desired component and limb alignment in comparison to that achieved by conventional TKA.…”