Interreader reliability assessment of hallux valgus evaluation on dorsoplantar weightbearing radiographs from a prospective multi-center trial and correlation with patient-reported outcome measures

Objective: To determine inter-reader reliability (IRR) of hallux valgus (HV) related parameters, i.e. intermetatarsal angle (IMA), hallux valgus angle (HVA), lateral round sign of the first metatarsal, tibial sesamoid position (TSP), metatarsus adductus angle (MAA), transverse osseous foot width, 1^st MT length, MTP osteoarthritis (OA), and distal metatarsal articular angle (DMAA). These were correlated with patient-reported outcome measures (PROMs). Materials and Methods: A prospective single-arm Level 3 multicenter clinical trial in which standardized radiographs and PROMs were collected at the time of the initial patient visit for pre-operative assessment. Two musculoskeletal radiologists performed measurements blinded to each other’s reads and clinical information. Intraclass coefficient and kappa were obtained for inter-reader analysis. A partial spearman rank order was used to correlate the measurements with PROMs. Results: The final cohort size of 183 patients had mean age of 40.77 years, mean body mass index was 26.11 kg/m², with 91.2% females and 8.7% males. There was excellent IRR for HVA (0.96, CI: [0.94,0.97]), IMA (0.92, CI: [0.89,0.94]), transverse osseous foot width (0.99, CI: [0.98,1.00]), and DMAA (0.80, CI: [0.74, 0.85]), good agreement for TSP (0.73, CI:[0.67,0.79]) and MAA (0.67, CI: [0.16, 0.84]), fair agreement for MTP OA (0.48, CI: [0.36,0.59]), and poor agreement for lateral round sign (0.32, CI: [0.11, 0.52]. The negative correlation of increasing transverse osseous foot width with worsening PROMIS physical but better MOxFQ and VAS scores is likely spurious. Conclusion: Good to excellent inter-reader reliability was observed for the most often used measurements for HV assessment without major trends in their correlations with PROMs. Lateral round sign is not a reliable finding in HV deformity.