The effect of total knee arthroplasty design on extensor mechanism function.
The effect of total knee arthroplasty design on extensor mechanism function was evaluated prospectively in a consecutive, single-surgeon series. Group 1 knees (n = 83) were implanted with a prosthesis that has a multiradius femoral component, and group 2 knees (n = 101) were implanted with a femoral prosthesis that has a single flexion-extension axis. Group 2 knees gained flexion more rapidly: At 6 weeks, the average flexion for was 94.5 degrees for group 1 and 107.1 degrees for group 2 (P<.001). Significantly more patients with group 2 knees were able to arise from a 16-inch (low) chair without using their arms starting at 6 weeks, and a difference was maintained through 2 years (90% vs 73%; P=.003). Patients with group 2 knees had significantly less anterior knee pain when rising from a seated position starting at 6 weeks, and a difference was maintained through 2 years (1% vs 22%; P=.001).
Mahoney
Ormonde M
OM
Athens Orthopedic Clinic P.A., Athens, Georgia, USA.
McClung
Christian D
CD
dela Rosa
Mylene A
MA
Schmalzried
Thomas P
TP
D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D007720:Knee Prosthesis; D008297:Male; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000601:surgery*; D011446:Prospective Studies; D011474:Prosthesis Design; D016059:Range of Motion, Articular