Simultaneous bilateral total knee replacement in a patient with achondroplasia and severe varus deformity: a case report.

We present a unique case of a 61-year-old female with achondroplasia and end-stage osteoarthritis of both knees who presented with severe pain and bilateral varus deformities of over 40 degrees. The patient underwent single-stage bilateral total knee arthroplasty (TKA) using cemented rotating-hinge implants with long stems. At 5-year follow-up, the patient has neutral limb alignment, pain-free ambulation without assistive devices, and stable implants on radiographs. This is one of the first reported cases of simultaneous bilateral TKA in a patient with achondroplasia and extreme bilateral varus deformity, highlighting how successful correction can be achieved using hinged implants and careful surgical planning, underscoring the feasibility of one-stage bilateral intervention in this rare and challenging scenario.