Periprosthetic acetabular fracture after total hip arthroplasty is relatively uncommon but can occur in high-energy trauma or in patients with bone loss secondary to osteolysis. We encountered a periprosthetic acetabular fracture after minor trauma. The fracture was minimally displaced, and was treated conservatively. After eight-weeks non-weight-bearing, the fracture was healed but the acetabular cup had migrated. Acetabular revision was performed with morcellized allograft and non-cemented acetabular cup. At the one-year follow-up, the injured hip showed good range of motion with a stable acetabular component.