Abstract
Patients often comment on swelling after foot and ankle surgery. However the relationship between swelling and outcome (pain and function) has not previously been outlined. A recent study by Pinsker and Daniels demonstrated that while swelling was rated as important by patients it was rarely included in outcome scores. The purpose of this paper was to determine the relationship between swelling and outcome after ankle fusion or replacement. A secondary purpose was to determine how this relationship changed in time, how swelling score changed before and after surgery, and determine differences in swelling score between total ankle replacement (TAR), open ankle arthrodesis (OAA) and arthroscopic ankle arthrodesis (AAA).
The COFAS prospective ankle arthritis database enrolls patients in 4 centers undergoing surgery by one of 6 surgeons since 2002. The MODEMS outcomes package from AAOS was used, with the validated ankle osteoarthritis score (AOS) score being used to assess outcomes in the pain and disability domains. The swelling score was indexed from 1 to 5, 1 being no swelling and 5 being severe swelling. Outcomes were recorded preoperatively and annually up to 2010. Statistical analysis was performed using 95% confidence intervals and correlations being determined using Pearson's correlation and r2 values.
The swelling score was correlated with AOS score with an r2 of 0.13 for postoperative patients. With the swelling score analysed categorically the difference of outcome was significant with a mean AOS score of 15.1 (CI 13.3 to 16.9) for a swelling score of 1, 23 (CI 21.7 to 24.9) for a swelling score of 2, 31 (CI 29.6 to 33.1) for 33.6 (CI 34.9 to 38.8) for 4, and 39 (CI 35.3 to 43.0) for 5. Swelling scores fell outside the 95% confidence intervals for all groups indicating that the AOS outcome of swelling score 5 patients was worse than the 4 group, 4 worse than 3, 3 worse than 2, and 2 worse than 1. Patients with swelling scores of 1 scored 24 points better than those with a swelling score of 5.
Swelling scores were the same preoperatively for total ankle arthroplasty, Arthroscopic and open fusions. However swelling scores were lower for arthroscopic fusions after surgery for all time periods at an average of 2.1 (CI 1.9 to 2.2), compared to total ankle arthroplasty (2.5, CI 2.4 to 2.6) and open ankle fusion (2.5, CI 2.4 to 2.6).
Swelling has a major relationship with outcome. Swelling may be the cause of poorer outcomes for open ankle fusion compared to arthroscopic. Swelling is an independent factor as swelling scores for TAA were higher compared to AAA despite similar outcomes. Arthroscopic surgery reduces the postoperative swelling. Methods to reduce swelling such as compression stockings, elevation, controlling bleeding may result in better outcomes. Minimising the invasiveness of surgery achieves this goal. Patient education about swelling, elevation and compression stockings would assist in these goals.
