Femoral nerve palsy (FNP) is a debilitating and relatively rare complication of total hip replacement, which can worsen the functional prognosis. Various surgical approaches, including posterior, lateral, and anterior, are employed in total hip arthroplasty (THA), and the chosen approach can influence which nerve is affected. There is currently a lack of recent research on the prevalence of FNP and its typical course of recovery. In this clinical case, we report a rare incidence of FNP that presented as a complication of primary THA in a patient with end-stage osteoarthritis secondary to developmental dysplasia of the hip (DDH). A 35-year-old female presented with groin pain and restricted movement in her hip joint. She had a history of undergoing complex open-reduction surgery for hip dysplasia. During the physical examination, a positive Trendelenburg gait was identified, along with end-stage osteoarthritis (OA) secondary to the dysplasia. She subsequently underwent THA using a posterolateral approach. Following the procedure, she experienced neurological symptoms, leading to the diagnosis of FNP, a rare occurrence.