Fracture of the patella after total knee arthroplasty is an infrequent complication. In the presence of poor remaining bone stock, avascular necrosis, removal of the implant with partial or complete patellectomy is recommended. Arthroscopic removal of a loose body or cement extrusion has been recently attempted successfully in very few cases, where loose and mobile cement fragments were involved and were often removed piecemeal. The authors experienced an unusual case of a patient a 69-year-old woman who, after having fallen down, presented a comminuted patellar fracture. We recommended an external orthosis and a temporary limitation of activity. Four months later, the patient complained. An X-ray revealed a necrosis of the proximal fragment and a lowering of the patellar button with the distal bone fragment. The removal of the patellar button was performed by arthroscopy. Conservative treatment can be successful for this patients and the removal of the patellar button loosening via arthroscopy appears to be an attractive technique to be used in similar cases.