An evaluation of the use of retrospectively acquired preoperative AOFAS clinical rating scores to assess surgical outcome after elective foot and ankle surgery

The use of retrospectively acquired preoperative AOFAS rating scores in cli nical research to assess the outcomes of elective foot and ankle surgery ha s not been validated. The data obtained utilizing this methodology may misr epresent the results and lead to spurious conclusions. This investigation c ompared preoperative AOFAS Ankle-Hindfoot scores obtained before and after surgery from patients who had undergone elective surgery to determine if re trospectively acquired scores match those collected prospectively. Only two out of 47 patients (4%) recalled identical AOFAS scores. The mean difference between the preoperative scores (preoperative score obtained aft er surgery minus preoperative score obtained before surgery) was -5.3 point s. Fifteen patients (32%) had preoperative scores that differed by 20 point s or more. Kappa statistics found little agreement among the five elements that comprised the two preoperative scores when responses obtained before a nd after surgery were compared to one another. The results suggest that pre operative clinical rating scores obtained after elective surgery are a poor predictor of the patient's preoperative condition and that studies which e mploy retrospectively acquired preoperative AOFAS clinical rating scores ma y overestimate the benefit of surgery.