Angle of BRINK - a new way to measure Haglund's deformity

Introduction Haglund's deformity, an abnormality of the postero-superior corner of the calcaneum, is a common, critically debated cause of posterior heel pain. Several radiological indices such as Fowler-Philip angle, Ruch pitch, Chauveaux-Liet angle, calcaneal pitch angle, parallel pitch lines, and X-Y ratio have been described to measure this deformity. However, most of these lack specificity and have variable intra- and inter-observer reliability. Purpose The study aims to describe a new radiological "angle of BRINK" (Botchu-Reilly-Iyengar-Nischal-Kakarala) to measure Haglund's deformity. Patient and methods We performed a retrospective cohort analysis, assessing 20 weight-bearing lateral ankle radiographs of patients with Haglund's deformity (Haglund's cohort) and 100 radiographs without the deformity (normal cohort). Demographic details and angle of BRINK to measure Haglund's deformity were measured for each patient. Statistical analysis was performed using t-test and inter-observer reliability was calculated using kappa coefficient. Results The mean angle of BRINK to measure Haglund's deformity in the normal cohort was 20.04 degrees (SD 4.88), and in the Haglund's cohort was 25.1 degrees (SD 3.3). This was statistically significant with a p-value of less than 0.0001. There was excellent intra- and inter-observer reliability with kappa value of 0.8. Conclusion Our proposed radiological angle of BRINK to measure Haglund's deformity is simple and easy to calculate on standard weight-bearing radiographs. Contrary to the traditional measurements used to estimate the deformity, it has shown a good intra- and inter-observer reliability and can support surgical decision-making process for management of patients with symptomatic Haglund's deformity.