A Long-Term Study of the Effect of Subtalar Arthrodesis on the Ankle and Hindfoot Joints

Background: Subtalar arthrodesis is a common therapy for subtalar joint disorders. In this article, we evaluate the effect of subtalar arthrodesis on the ankle and hindfoot joints. Methods: Fifty patients (33 men and 17 women) underwent subtalar arthrodesis between January 1, 1996, and August 31, 2011. The 36-item Short-Form Health Survey and American Orthopaedic Foot and Ankle Society ankle hindfoot scores were used for clinical evaluation. Radiographic analysis included assessment of degenerative changes and ankle and hindfoot joint function in the frontal and sagittal planes. Results: Thirty-seven patients (27 men and 10 women; mean age, 42.6 years) were followed up for an average of 9.2 years (range, 2-17 years). The mean +/- SD 36-item Short-Form Health Survey score improved from 30.21 +/- 7.19 before surgery to 78.50 +/- 12.23, and the American Orthopaedic Foot and Ankle Society ankle hindfoot score increased from 50.32 +/- 12.39 to 73.14 +/- 15.44. Degenerative changes in the talonavicular, calcaneocuboid, metatarsocuboid, and ankle joints occurred. The talar-vertical angle was positively related to the tibial-plantar minimal angle (affected side: r = 0.56; P < .01; healthy side: r = 0.46; P < .01). The difference in hindfoot height is positively related to the difference in tibial-plantar minimal angle (r = 0.54; P < .01). Conclusions: Subtalar arthrodesis is effective treatment for subtalar joint disease but could induce joint degeneration and ankle joint motion limitation related to talar declination and hindfoot height.