Abstract: A method for producing a customised surgical instrument or prosthesis for a specific patient is described. At least one x-ray image of a body part of the patient is captured. A statistical model having a dense set of anatomical correspondence points across the model is instantiated using image data derived from the at least one x-ray image to generate a patient specific model of the body part having a high accuracy surface. Patient specific data from the patient specific model is used to generate a design of the customised surgical instrument or prosthesis for use in a surgical procedure to be carried out on the body part. The surgical instrument or prosthesis is then manufactured using the design. A computer implemented method for generating the patient specific model of the body part is also described.