Intramedullary goniometer can improve alignment in knee arthroplasty surgery

Fifty total knee arthroplasties were performed using an intraoperative intramedullary goniometer to measure the angle of the distal femoral cut. When deviations of 1 degrees or more were found, angled cutting blocks ranging from 1 degrees to 5 degrees were used to recut the distal femur. Revised femoral cuts were made in 25 knees (50%). Postoperative evaluation from weight-bearing long-standing anteroposterior radiographs revealed an average distal femoral angle deviation from preoperative planning of 0.64 degrees (range, 0 degrees-3 degrees). This was statistically significantly different from the value for a comparison group of 50 knees on which arthroplasties were performed without the intraoperative goniometer with an average femoral angle deviation of 1.44 degrees (range, 0 degrees-4 degrees) (P < .05). In the control group, there were 7 knees (14%) that deviated by 30 or more versus only 2 knees in the study group. The authors conclude that an intramedullary goniometer is fast, is simple to use, and leads to more accurate preparation of the distal femur in total knee arthroplasty.