Objective: To report the effect of weightbearing x-ray imaging on clinical decisions in hallux valgus. Weightbearing (WB) x-ray is standard imaging for symptomatic hallux valgus (HV). In our clinical practice, often patients are presenting with non-weightbearing (NWB) x-rays. Repeated imaging requires additional radiation, justified only if expected to benefit patient's treatment. In this study, the influence of WB status on radiological HV parameters and on clinical decisions was analyzed.
Methods: In the dataset of WB and NWB x-rays, the hallux valgus (HVA) and intermetatarsal angle (IMA) were measured and differences analyzed. Clinical decisions for 10 x-ray pairs were studied among 40 respondents.
Results: The WB and NWB HVA difference ranged - 16 to 16° (p < 0.001) and IMA - 3.4 to 5.8° (p < 0.001). In only 45% of cases, the decisions based on NWB and WB imaging were consistent (kappa (95% CI) = 30.0 (23.7-36.3)).
Conclusions: Clinical decisions based on WB and NWB radiographs vary significantly. NWB films overestimate early and underestimate advanced HV deformity. Repeating radiographs is justified in patients presenting with NWB radiographs of symptomatic HV.
Keywords: Bunion; Hallux valgus; Imaging; Preoperative planning; Radiograph; Weightbearing.