Interobserver variability in Pirani clubfoot severity scoring system between the orthopedic surgeons

Congenital talipes equinovarus (clubfoot) is one of the most common congenital pediatric orthopedic foot deformity, which varies in severity and clinical course. Assessment of severity of the club foot deformity is essential to assess the initial severity of deformity, to monitor the progress of treatment, to prognosticate, and to identify early relapse. Pirani's scoring system is most acceptable and popular for club foot deformity assessment because it is simple, quick, cost effective, and easy. Since the scoring system is subjective in nature it has inter- and intra-observer variability, it is widely used. Hence, the interobserver variability between orthopedic surgeons in assessing the club foot severity by Pirani scoring system.

We assessed the interobserver variability between five orthopedic surgeons of comparable skills, in assessing the club foot severity by Pirani scoring system in 80 feet of 60 children (20 bilateral and 40 unilateral) with club foot deformity. All the five different orthopedic surgeons were familiar with Pirani clubfoot severity scoring and Ponseti cast manipulation, as they had already worked in CTEV clinics for at least 2 months. Each of them independently scored, each foot as per the Pirani clubfoot scoring system and recorded total score (TS), Midfoot score (MFS), Hind foot score (HFS), posterior crease (PC), emptiness of heel (EH), rigidity of equnius (RE), medial crease (MC), curvature of lateral border (CLB), and lateral head of talus (LHT). Interobserver variability was calculated using kappa statistic for each of these signs and was judged as poor (0.00-0.20), fair (0.21-0.40), moderate (0.41-0.60), substantial (0.61-0.80), or almost perfect (0.81-1.00).

The mean age was 137 days (range 21-335) days. The mean Pirani score was 3.86. We found the overall consistency to be substantial for overall score (total score kappa - 0.71) and also for midfoot (0.68) and hindfoot (0.66) separately. The consistency was least for the emptiness of heel (kappa - 0.39), and best for rigidity of equnius (kappa - 0.68) and rest of the parameters were moderate (kappa between 0.40 and 0.60).

The Pirani scoring system had got substantial reliability in assessing the clubfoot deformity even when the reliability test was extended to five different orthopedic surgeons simultaneously.