The purposes of this study are to compare the outcomes of the biodegradable implants for the fixation of ankle fracture and those of metallic implants, and to assess the problems of the biodegradable implants. Null hypothesis is that the clinical outcomes of biodegradable plate and screws for ankle fracture are not different from those of metallic implants.

Inclusion Criteria:

• skeletally mature subjects (≥16 years old) with unilateral ankle fractures

Exclusion Criteria:

• subjects less than 16 years old,
• subjects not followed up at this hospital,
• multiple injuries,
• bilateral ankle fractures,
• open fractures,
• pathologic fractures,
• concomitant tibial shaft fractures,
• previous history of immobilization due to significant injury or a fracture of either ankle,
• significant peripheral neuropathy,
• soft tissue infection in the region on either injured ankle,
• or inability to complete the study protocol