Obesity: Relevance for PAO Surgery

The question often comes up why do some surgeons ask that Body Mass Index (BMI) be below 30 for PAO surgery. There have been several studies that show a higher risk of complication in patients with an elevated BMI.  Let’s take a look at some of the literature published in medical journals.

In a study looking at results from three institutions with 280 patients included found that the probability of having a major complication was 22.3% in a patient with a BMI greater than 30, compared to 3.1% with a BMI less than 30.  A major complication (Grade 3 or higher) is a complication needing an invasive surgical or radiological intervention, unplanned hospital admission, a potentially life threatening complication or long term morbidity (Novias et al., 2015).

A paper published in 2018 by Wells et al found that increasing BMI was associated with a higher risk of a complication, and this study included 154 hips from 129 patients.

Mayer et al. found the rate of wound dehiscence, (this is when the incision reopens) and wound infections occurred at a rate of 30% in high BMI (BMI greater than 30) patients compared to 8.3% in low BMI patients.  It was also noted that blood loss was 150 ml higher in the high BMI group.  This study included 80 hips from 73 patients.  One of the take home points in this study was that PAO can be successful with a BMI greater than 30, but that there should be counseling regarding the higher risk of complications, and patients should be given the opportunity preoperatively to lose weight (2018).

Author: Cynthia Porcari, BSN, RN, CNOR


Mayer, S. W., Zelenski, N. A., Karas, V., Xie, Z., & Olson, S. A. (2018). High Body Mass Index is Related to Increased Perioperative Complications After Periacetabular Osteotomy. American Journal Of Orthopedics (Belle Mead, N.J.), 47(8).


Novais, E. N., Potter, G. D., Clohisy, J. C., Millis, M. B., Kim, Y. J., Trousdale, R. T., … Sierra, R. J. (2015). Obesity is a major risk factor for the development of complications after peri-acetabular osteotomy. Bone & Joint Journal, 97B(1), 29–34.


Wells, J., Schoenecker, P., Petrie, J., Thomason, K., Goss, C. W., & Clohisy, J. C. (2018). Are Complications After the Bernese Periacetabular Osteotomy Associated With Subsequent Outcomes Scores? Clinical Orthopaedics And Related Research.