Obesity in Revision Total Knee Arthroplasty - a Systematic Review and Legal Assessment

Background In recent years, the incidence of overweight and obesity has increased in the German population. Thus the number of obese patients treated with primary total joint arthroplasty has also increased. It is therefore predicted that the number of obese patients undergoing revision total joint arthroplasty will also increase. Nevertheless almost every manufacturer of commercially available revision arthroplasty implants states in his product safety guarantee that obesity is a relative or absolute contraindication. Data on revision total joint arthroplasty in obese patients are sparse. The aim of this systematic review is to assess the current literature on re-revision rate, infection rate, postoperative clinical outcome, and implant survival rate in obese patients undergoing revision total knee arthroplasty. Moreover, potential legal consequences and aspects are discussed which are essential for the surgeon. Material and Methods We conducted a systematic review of the online databases PubMed and identified clinical studies on obesity and overweight in revision total knee arthroplasty. Study quality was assessed using levels of evidence and the modified Jadad score. We also included descriptive data on case numbers, age, gender, height, weight and follow-up time. Current legal aspects were also analysed. Results/Discussion Five studies met the inclusion criteria and were included in the systematic review. The average Jadad score was 1, the average level of evidence 3. In two studies, infection and revision occured more often in obese patients. Patients with morbid obesity had a higher risk of wound revision and periprosthetic joint infections. Three studies showed that obese patients had significantly lower scores for clinical outcome measures in function and pain. The legal aspect was not discussed in any of the five studies. Overall, published data are sparse and very heterogeneous. Therefore comparing these five studies is difficult. However, the results of our review suggest that obesity in revision total knee arthroplasty may have a negative influence on reoperation rate, infection rate and postoperative functional outcome. From a legal point of view, potential weight limitations of the implants intented for use have to be part of the oral preoperative discussion. The patient's informed consent has to be received and documented prior to revision total joint arthroplasty.