medwireNews: Obese people have a significantly higher risk for complications, particularly infection, following total hip arthroplasty (THA) than non-obese people, results of a meta-analysis involving more than 2 million patients show.
“Surgeons should be aware of increased risks of superficial and deep infections, dislocations, readmissions, all-cause revisions and unplanned reoperations in order to counsel patients and adopt prophylactic strategies into clinical practice to reduce these risks where possible,” write James Onggo (Box Hill Hospital, Melbourne, Victoria, Australia) and co-authors in Osteoarthritis and Cartilage.
Their systematic review and meta-analysis included data for 581,012 obese (BMI≥30 kg/m2) and 1,609,812 non-obese (BMI<30 kg/m2) patients who underwent THA and had their outcomes reported in one of 67 prospective, retrospective, or case-controlled studies.
The researchers found that, overall, obese patients were a significant 1.53 times more likely than non-obese patients to experience any type of complication following THA.
The highest risk was for deep infections, at an odds ratio (OR) of 2.71, followed by superficial infections (OR=1.99), dislocations (OR=1.72), reoperations (OR=1.61), revisions (OR=1.44), and readmissions (OR=1.37).
Among a subgroup of 85,613 morbidly obese patients (BMI≥40 kg/m2), the risks were increased further. These patients were 2.68 times more likely to experience complications than non-obese patients, with the risks for deep infections (OR=3.69), superficial infections (OR=4.95), dislocations (OR=2.12), reoperations (OR=2.96), revisions (OR=2.17), and readmissions (OR=1.99) all significantly increased.
By contrast, neither the obese nor the morbidly obese patients had an increased risk for venous thromboembolism, peri-prosthetic fracture, or aseptic loosening.
Onggo and co-investigators also report that the obese patients undergoing THA had a significant 8.7-minute longer mean operative time than the non-obese patients as well as a 0.5-day longer mean length of in-hospital stay, but average blood loss was similar between the two groups.
The authors acknowledge, however, that a lack of raw data meant they were unable to compare overall survival of the joint replacements between the two groups.
Onggo et al hope that their study will “raise awareness amongst general practitioners, physicians and orthopaedic surgeons about the risks of hip replacement surgery in this population.”
They stress that “the results from this study should not be used to avoid performing THA in the obese population, but rather to use this information in the shared informed consent process for this patient group.”
The team concludes: “The information may also allow surgeons and peri-operative physicians to be prepared for these complications and better respond to them if or when they actually occur.”
By Laura Cowen
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Osteoarthritis Cartilage 2019; doi:10.1016/j.joca.2019.10.005