Should isolated morbid obesity influence the decision to operate in hip and knee arthroplasty?
Peter F. Crookes, MD, FRCS, Consultant Bariatric Surgeon, 1 Roslyn S. Cassidy, BSc (Hons), MMedSci, PhD, Data Analyst, 1 Aleksander Machowicz, BSc, Medical Student, 1 Janet C. Hill, MEng, MSc, PhD, Research Manager, 1 John McCaffrey, MB, BchBAo, FCARCSi, FCICMI FCICM, Consultant Anaesthetist, 2 Gillian Turner, MB, BChBAo, FFARCSi, Consultant Anaesthetist, 2 and David Beverland, MD, FRCS, Consultant Orthopaedic Surgeon 1Hip Knee
Aims
We studied the outcomes of hip and knee arthroplasties in a high-volume arthroplasty centre to determine if patients with morbid obesity (BMI ≥ 40 kg/m2) had unacceptably worse outcomes as compared to those with BMI < 40 kg/m2.
Methods
In a two-year period, 4,711 patients had either total hip arthroplasty (THA; n = 2,370), total knee arthroplasty (TKA; n = 2,109), or unicompartmental knee arthroplasty (UKA; n = 232). Of these patients, 392 (8.3%) had morbid obesity. We compared duration of operation, anaesthetic time, length of stay (LOS), LOS > three days, out of hours attendance, emergency department attendance, readmission to hospital, return to theatre, and venous thromboembolism up to 90 days. Readmission for wound infection was recorded to one year. Oxford scores were recorded preoperatively and at one year postoperatively.
Results
On average, the morbidly obese had longer operating times (63 vs 58 minutes), longer anaesthetic times (31 vs 28 minutes), increased LOS (3.7 vs 3.5 days), and significantly more readmissions for wound infection (1.0% vs 0.3%). There were no statistically significant differences in either suspected or confirmed venous thromboembolism. Improvement in Oxford scores were equivalent.
Conclusion
Although morbidly obese patients had less favourable outcomes, we do not feel that the magnitude of difference is clinically significant when applied to an individual, particularly when improvement in Oxford scores were unrelated to BMI.
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