OBESITY IN TOTAL JOINT ARTHROPLASTY

Dr Dermot Bowden, Mr James CashmanWaterford Regional HospitalDepartment of Trauma and Orthopaedics

Introduction

The World Health Organisation (WHO) defines Overweight as a Body Mass Index (BMI) of greater than 25 and Obese as a BMI of >30. Debate exists within the literature as to what if any effect obesity has on TJA outcomes. In this review, we discuss some of the relevant literature regarding obesity and its impact on outcomes in TJA.

Prevalence of ObesityAccording to the WHO, the worldwide obesity has nearly doubled since 1980, and in 2008 there were 1.4 billion overweight adults. As much as one third of the adult population of the USA is thought to be obese and similar figures for the UK reveal an equally worrying trend. (The most recent Government report on obesity in Ireland estimates the prevalence of obesity in Irish adults to be as high as 61%). Importantly, it is noted that those who were obese were more likely to be older and thus also more likely to require orthopaedic surgical intervention. As such, it is important that the treating surgeon be familiar with the excess likely risks associated with obesity, not only to council the patient as to the possible adverse outcomes, but also to enable potential pre-operative optimisation and better patient selection.

Medical Issues The medical issues associated with obesity are many and well documented in the literature, as such obese patients are likely to carry with them any or several of a multitude of other interrelated comorbid conditions. In particular, the association of obesity with cardiovascular disease and diabetes is pronounced, but there is also an association with osteoarthritis and some cancers and incredibly, 65% of the worlds population now live in countries where overweight and obesity kills more people than underweight. In one study of TJA in 14 morbidly patients (20 procedures)Glucose control Metabolic syndrome is common among this patient cohort. The principle challenge in the perioperative period is to adequately maintain glycaemic control in the setting of major surgery, periods of starvation. However, there are also other consequences for the patient such as delayed wound healing and increased infection risk which are all amenable to pre-operative optimisation by increased glycaemic control. It is well documented XX that obese patients can obtain improved glucose tolerance and insulin sensitivity when they lose weight and these patients should be offered dietetic advice and assistance to optimise their BMI before surgery. However, recidivist eating patterns are reported in most cases and interventions to help obese patients to lose weight are generally ineffective. Comorbid disease eg renal failure, CVS disease, Sleep Apnoea, Mood Disorder.

Surgical IssuesTechniqueThe obese patient presents a considerable technical challenge to the surgeon for a variety of reasons.Adiposity, tourniquet, manouevreability

Implant survival

Anaesthetic IssuesIncreased volume of distributionLow tolerance for ventilationDifficult spinal anaesthesia

Older patientsThe average age of a patient undergoing a total joint arthroplasty in the USA is

Technical difficultyDuration of procedureAdmission to intensive care unit

Implant survival

InterventionsDieticianExcerciseSurgery

Referenceshttp://www.who.int/mediacentre/factsheets/fs311/en/http://www.noo.org.uk/NOO_about_obesity/trendshttp://www.cdc.gov/obesity/data/adult.html