An evaluation of retrospective outcome scores in elective foot and ankle surgery.

BACKGROUND: Patient reported outcome measures are becoming more popular in their use. Retrospective scoring is not yet a validated method of data collection but one that could greatly decrease the complexity of research projects. We aim to compare preoperative and retrospective scores in order to assess their correlation and accuracy. METHODS: 36 patients underwent elective foot and ankle surgery. All patients were scored preoperatively using the SF-12 (including both the physical and mental subsets) and FFI. Patients then recorded both PROMs at the 3-month follow up (av. 139 days). Results were then analyzed for statistical significance. RESULTS: 36 patients (av. age 54.6): completed both sets of questionnaires. There were 15 hindfoot and 21 forefoot procedures. No retrospective scores were identical. The mean percentage difference between the preoperative scores was -7.9% (-17.3 to 1.6%, 95% CI) for Physical Component of SF12, -3.2% (-10.3 to 3.9%, 95% CI) for mental component of SF12 and 40.7% (25.3 to 56.1%, 95% CI) for FFI. This retrospective accuracy was statistically significant (p<0.001). When the scores were plotted against each other, the outcome measurements showed positive correlations (Physical SF 12 p=0.48, Mental SF 12 p=0.80 and FFI p=0.81). With both PROMs mean percentage differences combined, patients undergoing hindfoot procedures (3.5%; -5.0 to 12.1%, 95% CI) were more accurate with retrospective scoring than their forefoot counterparts (17.5%; 5.0 to 30.0%, 95% CI). This was not statistically significant (p=0.07). Using regression analysis, we found no significant statistical difference in the retrospective accuracy when compared against both time to retrospective scoring and the outcome measure at 3 months post operatively. CONCLUSION: Retrospective scoring appears to lack accuracy when compared to prospective methods. However, our data shows the SF12 is recalled more accurately than the FFI (p<0.001) and both the mental and physical components are recalled to within 10% of the pre-operative score. These results show patients tend to recall their symptoms at a worse level preoperatively than originally described, especially those with forefoot problems.

Perioperative changes in the microcirculation in feet after foot and ankle surgery.

The senior author (N.P.G.) observed that if the foot became dependent in the first 48 hours after foot surgery, the patient had swelling and pain. This effect seemed less after about 48 hours. The authors set out to see if there was a scientific basis for this. Laser Doppler was used to assess blood flow in 14 patients. Flow was recorded in the big toe, at heart level, and on dependency, preoperatively and postoperatively. Postural vasoconstriction was calculated, and time for blood flow to normalize was recorded. Mean postural vasoconstriction preoperatively was 51.31%; postoperative mean at 24 hours was 23.05%, at 48 hours 36.62%, and at 72 hours 44.24%. There was a difference between the preoperative levels and the 24-, 48-, and 72-hour postoperative levels (P < .05). Results showed that it takes longer than 72 hours rather than 48 hours for microcirculation to return to normal. The results emphasized the importance of postoperative foot elevation for at least 48 hours because of this phenomenon.