Patients who were obese and underwent total hip arthroplasty had lower Oxford Hip Scores at 6 months and an increased early revision rate compared with patients who had a lower body mass index, according to study results.
Searching the New Zealand National Joint Registry, researchers retrieved data for 5,357 patients who had primary total hip arthroplasty (THA) from October 2010 to December 2011. Outcomes included functional status as measured by the Oxford Hip Score at 6 months after surgery and revision for any reason. Associations between body mass index (BMI), American Society of Anesthesiologist (ASA) scores, length of surgery and cementation of components were also examined.
According to study results, younger patients had a high BMI whereas older patients had a low BMI. The smallest percentage of patients with ASA grade I were found in the obese and morbidly obese groups, whereas underweight and morbidly obese groups had a higher proportion of patients with ASA grade III and IV.
The researchers also found patients in the obese and morbidly obese groups had significantly greater proportions of fully uncemented prostheses, as well as fewer fully cemented or hybrid components.
Compared with patients in the healthy and overweight groups, patients in the obese, morbidly obese and underweight groups had significantly lower Oxford Scores. Additionally, operating times were significantly longer within the morbidly obese group compared with all other groups, according to the researchers.
Among the 73 revisions performed, the highest rate of revision was found among the morbidly obese group, followed by the obese and underweight groups. Kaplan-Meier survival estimates of 2-year revisions were 1.6% for underweight and healthy groups, 1% for the overweight group, 2% for the obese group and 2.3% for the morbidly obese group.
Disclosure: The authors have no relevant financial disclosures.