Inadequate pre-operative glycaemic control in patients with diabetes mellitus adversely influences functional recovery after total knee arthroplasty: Patients with impaired glycaemic control exhibit poorer functional outcomes at 1-year post-arthroplasty

Purpose Whilst inadequate glycaemic control is associated with an increase in perioperative complications following total knee arthroplasty, the impact of glycaemic control in this at-risk patient group remains ill-defined. Identification of at-risk patients would allow targeted pre-operative glycaemic control intervention. Methods One hundred consecutive patients with a diagnosis of diabetes mellitus and one hundred age, sex and BMI matched patients without diabetes undergoing total knee arthroplasty in a single institution were analysed between 2008 and 2013. Inadequate glycaemic control was defined as having an HbA1c of greater than 64 mmol/mol (8.0 % NGSP) measured within the 3 months before surgery. Patient demographics, diabetes management and complications of diabetes were recorded and used as explanatory variables to deliver a generalised linear model. This allows for relationships to be defined between change in patient-reported function (SF-36, WOMAC) and these explanatory variables. Results The patient group with concomitant diabetes exhibited smaller improvements in WOMAC and SF-36 physical component summary at 1 year after knee arthroplasty. This effect was most pronounced in the subset of patients with inadequate glycaemic control recorded in the early pre-operative period. Conclusion Patients with diabetes, particularly those with inadequate glycaemic control, exhibit less improvement at 1 year following knee arthroplasty than patients without diabetes mellitus. Clinical focus on modulating this factor in this at-risk group is warranted. Level of evidence III.