Charlson Index has been found to predict functional outcome, implant survival, mortality, length of hospital stay and resource use after arthroplasty. Obesity can influence the outcome following lower limb arthroplasty. Our aim was to identify if there was a relationship between Charlson index, obesity and disability and whether this relationship had altered in recent years.

Demographic details, Charlson index, BMI, SF-12 and oxford score were recorded prospectively for 88 consecutive patients undergoing lower limb arthroplasty between August 2011 and January 2012(Group B). The results were compared with Charlson index of 92 consecutive patients between August 2005 and March 2006(Group A).

The mean age for Group A was 70 years (range 41–90). 56(61%) were female and 36(39%) male. The mean Carlson index was 3 (range 0–6) and median was 3. The mean age for Group B was 67 years (range 45–91). 53(60%) were female and 35(40%) male. The mean Charlson index was 2.2 (range 0–11) and median was 0. The difference between the groups was statistically significant with a P value of 0.001. The mean BMI for Group B was 31 (range 15–56) and median 30. Thirteen patients (15%) had BMI<25, 29 patients (33%) had BMI between 25–29. 9(Pre-Obese), 23 patients (26%) had BMI between 30–34. 9(Obese-Class 1), 10 patients (11%) had BMI between 35–39. 9(Obese-Class 2)and 13 patients (15%) had BMI>40 (Obese-Class 3). The only difference between group B1(BMI<30) and B2(BMI>30) was of age with a P value of 0.0003 (72 vs 59 years).

The current group had less comorbidity but 85% of patients were overweight or obese. These patients were younger but there was no difference in their health or disability before surgery. The high prevalence of obesity may represent treatment selection of these patients away from waiting list centres. Consideration about the treatment of obesity should be given before lower limb arthroplasty.