The aim of this study was to evaluate the results of interpositional arthroplasty with tensor fascia lata or fat as a treatment for traumatic subtalar joint arthritis after a fracture of the calcaneus. From August 2006 to March 2008, 22 patients with traumatic subtalar joint arthritis were enrolled in this study. Tensor fascia lata was implanted for 7 patients who previously underwent surgery with the extensive lateral approach. Fat was implanted for 15 patients who were previously managed with conservative or percutaneous fixation. All the patients were followed up for more than 1 year, and the results were evaluated retrospectively. The Ankle-Hindfoot score by the American Orthopedic Foot & Ankle Society changed from 60.95 to 80.23 (p < 0.05). Visual Analogue Scale pain score decreased from 6.6 to 3.8 (p < 0.05). The results of the circle draw test were excellent in 8 patients, good in 11, and fair in 3 patients without any poor outcomes. The subjective satisfaction of the patients was excellent in 16 patients, good in 4 patients, and poor in 2 patients. In 2 patients with poor satisfaction, symptoms and mobility showed no improvement postoperatively. Interpositional arthroplasty with tensor fascia lata or fat as a treatment modality of traumatic subtalar joint arthritis could provide good clinical outcome and preservation of range of motion.