Author(s): Chen PQ
Using quantitative gait analysis and clinical evaluation, the functional results of 18 total knee replacement (TKR) in 13 patients who had osteoarthritis were evaluated. Nine knees each were replaced by Insall-Burnstein (I/B) posterior stabilized design or Miller-Galante (M/G) prosthesis. The former was fixed by cement and needed to sacrifice posterior cruciate ligament (PCL), while the latter was inserted without cement, and PCL could be reserved. The follow-up period ranged from 21 to 77 months. At the final follow-up, the overall functional knee score was 94.1 points (I/B 95.0 versus M/G 92.2). The average active knee flexion was 109.7 degrees (I/B 116.4 degrees versus M/G 102.9). For gait analysis, three cameras synchronized with 2 AMTI force plates were connected to the VICON system to provide kinetic and kinematic data during level walking. The data were compared with the non-operated side; and with younger subjects as normal control. They were supposed to possess normal knee functions. In patients after knee prosthesis, they tended to have slower velocity, shorter step length and less cadence. They also showed shorter swing and longer stance phases. In the M/G knee ground, the duration for double-limb support was longer, but shorter for single-limb support. The angles of knee flexion-extension of both prosthetic groups became narrower. Their ground reaction forces in both vertical and medio-lateral directions were larger than in the control groups, probably due to quadriceps dysfunction and subtle imbalance of the soft tissue-prosthesis complex around the joint.