A method of generating a surgical plan for an orthopaedic surgical procedure from medical image data using a surgical plan server, in which the steps of the method which are performed by the server comprise: (a) receiving an orthopaedic surgical plan request from a computing device of a healthcare facility via a network, (b) receiving a medical image of bony anatomy of a patient, (c) receiving constraint data corresponding to an orthopaedic surgical procedure to be performed upon the bony anatomy of the patient, (d) generating a surgical plan (218, 230) for the procedure, and (e) transmitting the surgical plan (220, 232) to the computing device of the healthcare facility via the network, characterised in that the steps of the method which are performed by the server further include: determining (216, 300) whether the orthopaedic surgical procedure is a difficult orthopaedic surgical procedure based on the received medical images and the received constraint data, and wherein determining whether the orthopaedic surgical procedure is a difficult orthopaedic surgical procedure includes after step (c) and before step (d): determining patient-specific anatomical data from the received medical image of the bony anatomy of the patient; comparing the patient-specific anatomical data to historical anatomical data maintained in a surgical procedure database to determine whether the bony anatomy of the patient is similar to the bony anatomy of another patient on which a previous orthopaedic surgical procedure has been performed; determining whether the patient-specific anatomical data is outside a reference range or exceeds a reference threshold; and determining that the orthopaedic surgical procedure is a difficult orthopaedic surgical procedure based on: determining that the bony anatomy of the patient is similar to the bony anatomy of another patient that underwent a similar previous orthopaedic surgical procedure and determining that the previous orthopaedic surgical procedure was difficult; and determining that the patient specific anatomical data is outside of the reference range or exceeds the reference threshold, in which a first surgical plan for the surgical procedure is generated in step (d) by retrieving a surgical procedure from a surgical procedure database if it is determined that the procedure is not difficult, and instead, if it is determined that the procedure is difficult, the steps of the method which are performed by the server include (i) transmitting via the network to a remote computing device the received medical image and the constraint data corresponding to the orthopaedic surgical procedure, the remote computing device having means enabling the medical image and the constraint data to be reviewed by one or more surgeons so that the surgeons can make a recommendation affecting the orthopaedic surgical procedure, wherein the recommendation is a surgical plan modification, and (ii) receiving the recommendation from the remote computing device via the network, the surgical plan that is generated for the procedure then being a second surgical plan generated by retrieving a surgical procedure for the previous orthopaedic surgical procedure determined to be difficult from the surgical procedure database and including extra and/or modified steps based on the recommendation received, and different from the first surgical plan. (a) receiving an orthopaedic surgical plan request from a computing device of a healthcare facility via a network, (b) receiving a medical image of bony anatomy of a patient, (c) receiving constraint data corresponding to an orthopaedic surgical procedure to be performed upon the bony anatomy of the patient, (d) generating a surgical plan (218, 230) for the procedure, and (e) transmitting the surgical plan (220, 232) to the computing device of the healthcare facility via the network, determining patient-specific anatomical data from the received medical image of the bony anatomy of the patient; comparing the patient-specific anatomical data to historical anatomical data maintained in a surgical procedure database to determine whether the bony anatomy of the patient is similar to the bony anatomy of another patient on which a previous orthopaedic surgical procedure has been performed; determining whether the patient-specific anatomical data is outside a reference range or exceeds a reference threshold; and determining that the orthopaedic surgical procedure is a difficult orthopaedic surgical procedure based on: determining that the bony anatomy of the patient is similar to the bony anatomy of another patient that underwent a similar previous orthopaedic surgical procedure and determining that the previous orthopaedic surgical procedure was difficult; and determining that the patient specific anatomical data is outside of the reference range or exceeds the reference threshold, determining that the bony anatomy of the patient is similar to the bony anatomy of another patient that underwent a similar previous orthopaedic surgical procedure and determining that the previous orthopaedic surgical procedure was difficult; and determining that the patient specific anatomical data is outside of the reference range or exceeds the reference threshold,