Defining the Patient Acceptable Symptom State Using PROMIS Following Reconstruction of the Progressive Collapsing Foot Deformity
Authors: Streeter Stone R. , Kush Sophie , Cororaton Agnes , Henry Jensen , Ellis Scott J. , Conti Matthew S. 
Published: April 2024

Introduction/Purpose:

Although reconstruction of the flexible progressive collapsing foot deformity (PCFD) has been shown to improve patient-reported outcomes (PROs), there is limited data describing postoperative success as defined by patient satisfaction following surgery. Distinct from the minimal clinically important difference (MCID), the patient acceptable symptom state (PASS) is a novel PRO measurement that represents the symptom threshold beyond which patients are satisfied with their postoperative outcome. The primary aim of this study was to use Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) and Pain Interference (PI) scores in combination with anchor questions to define PASS thresholds following reconstruction of the flexible PCFD. A secondary aim was to analyze how patient-specific variables and certain PCFD reconstruction procedures may impact the probability of reaching PASS thresholds.

Methods:

Using data collected from a foot and ankle orthopedic registry at a large academic institution, 109 patients who underwent reconstruction of a flexible PCFD between February 2019 and March 2021, had preoperative and 2-year postoperative PROMIS PF and PI scores, and 2-year postoperative responses to two PASS anchor questions (the delighted-terrible scale and the satisfied scale) were included in the study. Patients who underwent either a double or triple arthrodesis were excluded. Patient responses to the anchor questions were dichotomized and receiver operating characteristic (ROC) curve analyses were performed. Using the Youden Index to balance sensitivity and specificity and maximize the area under the curve (AUC), PASS thresholds with 95% confidence intervals were quantified using 2000 bootstrapped iterations. Lastly, multivariable logistic regressions were performed to analyze the influence of patient demographics, preoperative PROMIS scores, and certain PCFD reconstruction procedures on the probability of reaching the PASS thresholds.

Results:

The PASS threshold for PROMIS PF was found to be 42.6 using both the delighted-terrible and the satisfied scale and 73.4% of patients (80/109) reached the threshold (both AUCs: 0.91) (Table 1). The PASS thresholds for PROMIS PI defined using the delighted-terrible scale and the satisfied scale were 54.5 (AUC: 0.90) and 57.5 (AUC: 0.91), respectively, with 72.5% of patients (79/109) and 81.7% of patients (89/109) meeting the respective thresholds. Neither patient demographics nor specific PCFD reconstruction procedures affected the probability of meeting the PASS thresholds. However, a lower preoperative PROMIS PF score or a higher preoperative PROMIS PI score significantly decreased the probability of achieving the PASS thresholds.

Conclusion:

Following reconstruction of the flexible PCFD, PASS thresholds for the PROMIS PF and PI domains were found to be lower and higher, respectively, than population norms. This suggests that patients may be satisfied with the outcome of their surgery despite not returning to the population mean. The probability of achieving the PASS thresholds was influenced by both preoperative PROMIS PF and PI scores but not by patient demographics or certain PCFD reconstruction procedures. In addition to guiding future outcomes research, these results may help foot and ankle surgeons optimize treatment for the flexible PCFD and better manage patient expectations.