Abstract
Aim
The aim of this study is to evaluate if obesity negatively affects: (1) complication rate, (2) reoperation and revision rate and (3) functional outcome (based on patient reported outcome measures, PROMs) in revision total hip arthroplasty (rTHA). To our knowledge this is the only recent study to prospectively review these three aspects in what might be considered challenging rTHA.
Methods
444 rTHAs (cup, stem, both, n= 265, 57, 122 respectively), performed in a specialized high-volume orthopaedic center from 2013 to 2015, were prospectively followed. Complications and Oxford Hip Score (OHS) were evaluated at 4 months, 1 year and 2 years. Thirtyfour patients had a BMI >35 kg/m2 (obese), of which thirteen patients with a BMI >40 kg/m2 (morbidly obese).
Results
Infection following rTHA was more common in obese patients (8/34: 24%) and in morbidly obese patients (5/13: 38%) than in non-obese patients (15/410: 4%; p's < 0.001). No differences between obese and non-obese groups for other complications were observed (aseptic loosening, dislocation, periprosthetic fractures, thromboembolic events). Reoperation and revision rates were similar overall (p = 0.067 / 0.303 respectively) and due to infection (p = 0.469 / 0.879 respectively) for obese and non-obese groups. Scores on the OHS improved from 42 ±13 at baseline to 27±12 at 1 and 2 year follow-up (p < 0.001). Obese patients had overall poorer OHS scores than non-obese patients (p < 0.001), but improvement of OHS did not differ between obese and non-obese patients (p = 0.198).
Conclusion
Obesity is associated with an increased risk of infection following revision THA. Patients with high BMI should be counselled appropriately before surgery.
