The development of an acute respiratory distress syndrome following hip surgery in elderly patients is suggestive of thromboembolism in most instances. However, we must keep in mind the possibility of rarer complications, which can remain undiagnosed because they are hidden by prominent abnormal behaviours, which can develop following any type of anaesthesia. We report the case of a patient who developed a confusion following an orthopaedic surgery under spinal anaesthesia; this confusion concealed a penetration syndrome resulting from accidental inhalation of a dental crown. Because this patient was old and had previously developed chronic lung disorders, we selected a spinal anaesthesia for performing the surgery; these underlying respiratory disorders worsened the clinical consequences of the inhalation. The dental crown was removed under general anaesthesia with spontaneous ventilation using a bronchoscope after an unsuccessful attempt with a fibrescope due to the size of the foreign body.