Self-made distal femoral extramedullary positioning osteotomy template in total knee arthroplasty

[Abstract] Objective To investigate the accuracy and feasibility of using a homemade distal femoral extramedullary positioning osteotomy template to position the distal femur for total knee replacement during initial total knee arthroplasty. Methods From September 2019 to February 2021, 35 consecutive cases of advanced osteoarthritis or rheumatoid arthritis (extramedullary positioning group), 10 males and 25 females, aged 56 ?80years, average (69.09±5.70years), underwent total knee replacement with distal femoral osteotomy using a homemade extramedullary positioning template. 35 consecutive cases of advanced osteoarthritis or rheumatoid arthritis with total knee replacement by distal femoral osteotomy with conventional intramedullary localization (intramedullary localization group), 9males and 26 females; age 55 ?79 years, mean (67.17±5.38) years. The extramedullary positioning osteotomy template was referenced to the tibial osteotomy surface. ¬¬The lower limb force line was determined by the center of the femoral head, the knee joint center, and the ankle joint center to complete the distal femoral osteotomy. We compared the intraoperative bleeding, postoperative drainage, knee mobility at 1 and 2 weeks postoperatively, the deviation of hip-knee ankle (HKA) angle from the ideal value on x-ray within one week postoperatively, and the difference of femoral prosthesis coronal plane angle and femoral prosthesis flexion angle between the two groups. Results: There were no statistically significant differences in age, sex, body mass index, deviation of preoperative HKA from the ideal value, Hospital for Special Surgery (HSS) knee score, and knee mobility between the two groups. The operative time was (96.57±8.576)min and (89.97±10.051) minutes in the extramedullary and intramedullary localization groups. The intraoperative bleeding was (104.8 ± 8.864) ml and (95.4±9.372)ml, respectively, and the postoperative drainage was (179.43_+48.443)ml and (229.29±55.095)ml, respectively, and the differences were statistically significant (P0.05). Conclusion: The use of homemade osteotomy templates for distal femoral extramedullary positioning can shorten the time of total knee replacement surgery, reduce trauma and bleeding, and have higher accuracy in coronal and sagittal positioning of the femoral prosthesis than intramedullary positioning, with the same effect on the improvement of knee function and knee mobility in the early postoperative period. [Keywords] Arthroplasty, replacement, knee; positioning markers; femur