The epidemiology of severe obesity in patients undergoing total knee replacement in the kingdom of Fife over the last 20 years

Aim
Obesity is associated with increased risk of postoperative complications such as wound infection and venous thromboembolism. The aim of our study was to assess changes in the epidemiology of severe obesity (WHO classification, BMI ≥ 40) in NHS Fife, Scotland, from 2001-2021 in patients undergoing Total Knee Replacement (TKR).

Method

A retrospective analysis of prospectively collected data was performed for 7320 patients, who underwent TKR between 2001 and 2021. Obese patients with BMI ≥ 40 were studied and their demographic details, rates of severe obesity, and length of stay were studied from 3 discrete years (2001, 2011 and 2021) in order to examine changes over time.

Results

A total of 474 patients with BMI ≥ 40 underwent TKR between 2001 and 2021. In 2001, 2.73% of TKR’s performed were in severely obese patients; this rose to 9.25% in 2011 and 10.24% in 2021. This constitutes a significant increase of 7.51% over the 20-year period (p = 0.0186).

Male/Female ratio was 67/33% in 2001, 41/59% in 2011 and 35/65% in 2021. Mean age was unchanged, from 61(SD13.23) in 2001 to 63 (SD 8.89) in 2021 (p = 0.807). Mean length of stay decreased significantly from 7.33 (SD 1.53) to 2.50 (SD 1.33) over the same period (p = 0.024).

Conclusions

Rates of severe obesity have significantly increased in patients undergoing TKR over the last 20 years in our region. Careful patient selection and informed discussion about the high risk of complications is extremely important to manage patient expectations in the presence of severe obesity.