Body mass index and in-hospital postoperative complications following primary total hip arthroplasty

The influence of obesity measured in terms of body mass index (BMI) on the complication rates following total hip arthroplasty (THA) is a matter of debate.

This retrospective study conducted at a tertiary referral centre at Brisbane, Australia, examines the association between BMI and in-hospital postoperative complications, length of operating time and duration of hospital stay in 964 patients, who underwent THA from 2006 to 2010.

Amongst patients undergoing primary THA, when compared to the normal weight patients, those with BMI between 25 kg/m² and 29.9 kg/m² (overweight) and those with BMI between 35 kg/m² and 39.9 kg/m² (obese class II) had lower odds of perioperative complications (odds ratio [OR]: 0.62 (95% confidence intervals [CI], 0.43–0.92, p = 0.016) and OR: 0.60 (95% CI, 0.36– 0.99, p = 0.047 respectively). Patients with BMI less than or equal to 40 kg/m² were also associated with significantly lower odds of cardiac complications (p = 0.02). With unadjusted regression analysis, it was noted that those with BMI ≥40 kg/m² had the highest odds of developing infectious complications (OR 2.68, 95% CI, 1.08–6.65, p < 0.05). As the BMI increased, there was a statistically significant increase in length of operating time (p < 0.001).

There is a significant impact of BMI on the occurrence of perioperative complications following THA. Compared to normal weight category, the overweight and obese class II patients had a lower likelihood of developing overall, especially cardiac complications. Length of operating time increases along with an increase in BMI.