Unicondylar Knee Arthroplasty Using Minimally Invasive Surgical Technique

PURPOSE: To evaluate the results of unicondylar knee arthroplasties using minimally invasive surgical(MIS) technique. MATERIALS AND METHODS: During the years 2000 and 2001, 195 unicondylar knee arthroplasties were completed by senior author with the Miller-Galante prosthesis(Zimmer, Warsaw, IN, USA). We analyzed clinical results, flexion/extension gap laxity and the radiological findings. RESULTS: The average preoperative range of motion(ROM) was 122 degrees. At the first follow-up appointment after the surgery, the average ROM was 111 degrees and it was improved to 130.1 degrees at 1-year follow up. The preoperative hospital for special surgery score was 53.8 and it was improved 92.4 postoperatively. The average extension gap for all of the surgeries was 1.47 mm and the flexion gap was 1.82 mm. The average correction of overall alignment on the follow-up x-rays was 3.9 degrees for the varus knees. The x-rays showed an increase of distal femoral valgus angle(1.79 degrees ) with 6 mm cut than with the 8mm cut(0.37 degrees ). The average proximal tibial varus angle was decreased from 5.45 degrees to 2.11 degrees and the average posterior slope of proximal tibia was decreased from 7.2 degrees to 4.5 degrees . CONCLUSION: Unicondylar knee arthroplasty by MIS technique guarantees early recovery and satisfactory radiological results. Therefore, long term follow-up evaluation is necessary.

Auto-Transfusion in Total Knee Arthroplasty

PURPOSE: The purposes of this study are to see how much the auto-transfusion reduce the need for allo- genic blood transfusion and to ascertain whether transfusion affects the incidence of deep vein thrombo- sis(DVT) in primary total knee arthroplasty(TKA). MATERIALS AND METHODS: A retrospective analysis of 263 consecutive patients who had had a primary TKA was performed. The operations included 165 unilateral and 98 one-stage bilateral cases. The predeposit autologous blood donated 1pint for the unilateral cases and 2pints for bilateral cases preoperatively. Intraoperative salvage of blood was performed using the cell saver system. The collected data from the patients charts(the estimated blood loss and the amount of transfusion) were statistically analysed to examine relationships between development of DVT and the loss of blood or transfusion. RESULTS: We excluded the data of the patients who needed to be transfused over 6pints. For the unilateral cases, the average estimated loss of blood was 307+/-150cc(50~1000), the average amount of transfusion was 1.5+/-0.8 pint(0~5), and the average amount of blood that was salvaged through cell saver system was 210+/-141 cc(0~660). Adding the autologous donation(400cc), auto-transfusion was up to 100% of the average amount of transfusion. For the one-stage bilateral cases, the average estimated loss of blood was 678+/-267cc(100~1400), the average amount of transfusion was 3.0+/-0.9 pint(1~5), and the average amount of blood that was salvaged through cell saver system was 524+/-279cc(125~1125), Adding the autologous donation(800cc), auto-transfusion was up to 100% of the average amount of transfusion. There were no statistical associations between DYT and the loss of blood or transfusion(p>0.05). CONCLUSION: Combining preoperative autologous blood donation with intraoperative salvage effectively reduces the need for allogenic blood transfusion in primary TKA.