The data from this study may be useful for both patient and physician to consider when deciding on a suitable treatment in potential surgical candidates suffering from femoroacetabular impingement.

Purpose.To compare early outcome of total knee replacement (TKR) using computed tomography (CT)-based patient-specific cutting blocks versus standard instrumentation. Methods. 40 men and 44 women (90 knees) aged 45 to 88 (mean, 65) years who underwent TKR using standard instrumentation were compared with 39 men and 43 women (90 knees) aged 44 to 85 (mean, 64) years who underwent TKR using CT-based patientspecific cutting blocks. A single surgeon performed all TKRs through the medial parapatellar approach using a cemented prosthesis, with the posterior cruciate ligament retained and the patella resurfaced. Results. Respectively in the standard and patientspecific instrumentation groups, 74 and 70 patients were followed up for a mean of 30 and 14 months. The mean Oxford Knee Score was 19 and 19 preoperatively, 34 and 34 at 3 months, and 37 and 40 at 12 months (p=0.02). 71% and 88% of patients achieved good-toexcellent outcome (Oxford Knee Score of >34) at 12Early outcome after total knee replacement using computed tomography-based patientspecific cutting blocks versus standard instrumentation months (p=0.008). The respective mean EQ-5D score was 54 and 52 preoperatively, 73 and 76 at 3 months, and 77 and 78 at 12 months. 18% and 2% of patients required a blood transfusion (p=0.0002), with a mean blood loss of 292 and 254 g/l (p=0.049). The mean tourniquet time was 45 minutes in both groups. There was no infection or revision in either group. Conclusion.Compared with standard instrumentation, the use of CT-based patient-specific cutting blocks for TKR achieved higher Oxford Knee Score at 12 months and lower blood loss and transfusion rate.

Purpose: To assess the accuracy of total knee replacements (TKRs) performed using CT-based patient-specific instrumentation by postoperative CT scan. Method: Approval from the Ethics Committee was granted prior to commencement of this study. Fifty prospective and consecutive patients who had undergone TKR (Evolis, Medacta International) using CT-based patient-specific instrumentation (MY KNEE, Medacta International) were assessed postoperatively using a CT scan and the validated Perth protocol measurement technique. The hip-knee-ankle (HKA) angle of the lower limb in the coronal plane; the coronal, sagittal, and rotational orientation of the femoral component; and the coronal and sagittal orientation of the tibial component were measured. These results were then compared to each patient's preoperative planning. The percentage of patients found to be less than or equal to 3 of planned alignment was calculated. One patient was excluded as the femoral cutting block did not fit the femur as predicted by planning and therefore underwent a conventional TKR. Results: Ninety-eight percent of patients were within 3 of planned alignment in the coronal plane reproducing the predicted HKA angle. Predicted coronal plane orientation of the tibial and femoral component was achieved in 100% and 96% of patients, respectively. The sagittal orientation of the femoral component was within 3 in 98% of patients. The planned sagittal positioning of the tibial component was achieved in 92% of patients. Furthermore, 90% of patients were found to have a femoral rotation within 3 of planning. Eighty-six percent of patients achieved goodto-excellent outcome at 12 months (Oxford Knee Score > 34). Conclusion: We have found that TKR using this patientspecific instrumentation accurately reproduces preoperative planning in all six of the parameters measured in this study.