ABSTRACT
Autosomal dominant osteopetrosis (ADO) is a sclerotic bone disorder due to failure of osteoclasts. ADO poses difficulties during arthroplasty because of the increased chance for iatrogenic fractures due to sclerotic bone. ADO is divided into two types based on radiological findings, fracture risk, and osteoclast activity. These differences suggest less brittle bone in patients with ADO I compared to that of patients with ADO II, which suggests a smaller chance of preoperative fractures during cementless arthroplasty in ADO I compared with that in ADO II. A case of cementless total knee arthroplasty in a patient with ADO I is presented. Total hip arthroplasty was performed during follow-up, and known major problems related to ADO II were experienced. Therefore, the differences between ADO I and ADO II may not be clinically relevant for an iatrogenic fracture during arthroplasty in patients with ADO.