Metabolic Optimisation in Total Joint Arthroplasty: A Single-Centre Retrospective Cohort Pilot Study on the Safety and Feasibility of a Digitally Supported Perioperative Diet Modification

<b>Background/Objectives</b>: Obesity and type 2 diabetes are increasingly common among patients undergoing hip and knee arthroplasty and are associated with higher risks of prosthetic joint infection, impaired wound healing, and prolonged hospitalisation. Dietary carbohydrate restriction has demonstrated benefits in glycemic control and weight reduction, but its feasibility and safety in the perioperative arthroplasty population remain underexplored. This pilot study evaluated the safety, feasibility, and short-term metabolic effects of a low-carbohydrate diet supported by WhatsApp-based meal photo-logging in patients undergoing total hip or knee arthroplasty. <b>Methods</b>: A retrospective cohort analysis was performed on 43 patients enrolled in a carbohydrate-restricted dietary programme between 2021 and 2024. Patients submitted photographs of all meals via WhatsApp with a minimum contact frequency of four times daily, enabling real-time feedback and medication adjustment. Anthropometric and metabolic parameters, including weight, BMI, HbA1c, renal function, and lipid profile, were assessed before and after the intervention. <b>Results</b>: Participants (mean age 69.12 ± 7.51 years) demonstrated significant improvement across several metabolic markers. Mean weight decreased by 5.74 kg (<i>p</i> < 0.001), BMI by 2.26 kg/m² (<i>p</i> < 0.001), and HbA1c by 0.72% (<i>p</i> < 0.001). No episodes of severe hypoglycaemia or perioperative discharge delays related to glycemic instability were observed. Renal function remained stable, with no significant change in eGFR (<i>p</i> = 0.442). Among patients with available lipid data (<i>n</i> = 14), LDL-cholesterol and total cholesterol increased, while triglycerides showed a non-significant downward trend. <b>Conclusions</b>: A low-carbohydrate diet combined with high-frequency digital monitoring appears feasible and safe, achieving meaningful short-term improvements in weight and glycemic control without adverse renal or hypoglycemic events. The lipid changes observed, however, warrant cautious interpretation. These findings are hypothesis-generating, and larger prospective studies are needed to confirm the clinical impact of this approach and its relevance to perioperative optimisation.