In the current austere financial climate within the NHS where local healthcare Trusts are reimbursed in a Payment by Results system it is important that we accurately identify the costs associated with surgical procedures.

We retrospectively reviewed data of 589 consecutive patients undergoing lower limb arthroplasty surgery and recorded their age, BMI and co-morbidities. The effect of these parameters on operative duration and length of stay (LOS) was analysed.

We demonstrate that for a 1 point increase in BMI we expect LOS to increase by a factor of 2.9% (p<0.0001) and mean theatre time to increase by 1.46 minutes (p<0.0001). We also show that for a l-year increase in age, we expect LOS to increase by a factor of 1.2% (p<0.0001).

We have calculated the extra financial costs associated with this and believe that the current OPCS coding system for obesity underestimates the financial impact of increasing BMI and age on lower limb arthroplasty Trusts are being inadequately reimbursed.

The results of this study have been used to produce a chart that allows prediction of LOS following lower limb arthroplasty based on BMI and age. We also believe that the data produced is of use in planning operating lists.