Introduction

There is a clear rise in obesity worldwide and this is also seen in larger numbers of Total Knee Arthroplasty (TKA) in patients with high Body Mass Index (BMI). A 2019 systematic review has shown there is significant functional and quality of life improvements following TKA across all weight groups, but high BMI is also associated with increased risk of morbidity, including surgical site infection, pulmonary embolism and a higher all-cause mortality.

Aim

This review presents the current evidence-base and impact of different management strategies that should be considered for patients with high BMI who are being recommended for a TKA.

Methods

The literature presented is divided into 5 different management modalities: patient-directed weight loss, dietician advice, physiotherapy, endocrine therapies and bariatric surgery. The evidence base for each of these will be explored in detail and the impact of each of these will be summarised as potential options for those patients awaiting TKA surgery.

Results

1) Pre-operative weight loss programs merit serious consideration as they have been shown to decrease the impact of osteoarthritis-related symptoms although there is some research to suggest that these improvements are only temporary. 2) Dietary advice is often considered as part of a patients pre-operative management but the evidence surrounding the impact of this on patient symptoms and reduction in BMI is less clear. 3) Physiotherapy has been one of the mainstay non-operative treatments prior to considering TKA surgery; in the context of high BMI however there is emerging evidence to show that this provides a sustained improvement in a patient’s physical function when combined with dietary treatments. 4) Endocrine therapies and medications that help patients to consistently lose weight (e.g. Orlistat) have been studied extensively and have been shown to be effective in the long-term treatment of obesity having an impact on patients comorbidities and their arthritis symptoms – a recent trial has demonstrated persistent weight reduction following Semaglutide administration, with significantly improved patient benefits. 5) Bariatric surgery is another treatment arm where the literature remains undecided, relating specifically to short- and longer-term impact on arthroplasty-related outcomes. However it would seem plausible to assume a significant improvement in a patients BMI having bariatric surgery would have an improvement in outcomes though this is yet unproven in the literature, and certainly would be limited by patient selection at the bariatric assessment stage.

Conclusion

At this stage there is still little consensus with regards to optimal treatment options for all patients with high BMI being considered for TKA surgery. Increases in obesity are set to continue and the implications of this on healthcare at a patient and national levels should be considered carefully. This review has highlighted the paucity of the current evidence evaluating impact of treatments for high BMI and further research is clearly needed to establish patient outcomes and defining pathways in this expanding patient cohort.