Radiological evaluation of total knee arthroplasty

X-Ray analysis of a subset of TKA performed using a standard posterior cruciate ligament [PCL] retaining cemented technique to study the component malposition, overall post-operative alignment and mechanical loosening with respect to components positioning during follow-up period. This is a prospective study where we radiographically evaluated twenty-six primary TKAs [15 right and 11 left] in 20 patients [six patients received two stage bilateral total knee replacement] performed between July 2004 and December 2005. There were a total of 13 women and 7 men. The mean age at the time of the operation was 68 years and the follow-up period ranged from 18-32 months. The indication for knee replacement in all cases was advanced osteoarthritis. Radiographs were done immediately postoperative, at 6 weeks, at 3 months, at 6 months and then every year after surgery, and each time were compared to the postoperative controls. The overall alignment was acceptable in 19 knees, 3 had excessive valgus and 4 had varus alignment. At the last follow-up which was up to 32 months in some cases, none of the cases developed loosening as evidenced by non appearance of radiolucent zones or shifts in the position of the components. Moreover, the seven cases with joint malalignment didn't show signs of aseptic loosening within the available follow-up period. For the patellar angle, the mean tilt angle was 12° +/- 6°. In 17 knees the patellar prosthesis was displaced superiorly, and in seven cases there was medial displacement of the patellar prosthesis. Evaluation of total joint arthroplasty must be clinical, radiological and with annual intervals, in order to discover early failure signs. Proper alignments are critical for achieving good results thus keeping loosening to a minimum. Concerning the present study, aseptic loosening was not a complication of the toted knee arthroplasty evaluated at a follow-up period of up to almost three years in some cases, including those cases with documented postoperative joint malalignment

Assessment of the range of motion after total knee arthroplasty for osteoarthritic knees

A prospective study was performed to evaluate the range of motion after total knee replacement for osteoarthritis, one year postoperatively, by comparing it to baseline value. Forty-two knees [23 right and 19 left] primary TKAs in 36 patients [six patients received two stage bilateral total knee replacements] were performed between July 2004 to September 2006. There were a total of 22 women and 14 men. The mean age at the time of the operation was 68 years [range 53 - 82 years]. The average duration of follow-up was 18 months [range 14-22 months]. All prostheses were cemented preserving the posterior cruciate ligament Three different models were used namely: P.F.C. SIG-MA[R] Total Knee System from DePuy, AGC[R] Total Knee System from Biomet, and Columbus[R] Total Knee System from Aesculap. The diagnosis of osteoarthritis was established in all cases. The parameters evaluated were age, sex, preoperatlve knee flexion and extension range, preoperative flexion arc, tibiofemoral angle, and implant design. Advanced age, female gender, and good preoperative flexion and flexion arc were related to better postoperative flexion. Preoperative tibiofemoral malalignment had no significant effect on postoperative flexion. Advanced age, female gender, and good preoperative flexion and flexion arc are related to better postoperative range of motion particularly the degree of flexion