A functional and radiographic analysis of the total condylar knee arthroplasty.
Twenty-one knees in 14 patients were studied during walking, in clinical follow-up, and radiographically. The purpose was to examine the relationship between dynamic loading at the knee joint during level walking in the early postoperative period (1-2 years) and longer-term (4 years) prosthetic performance. Joint kinematics and kinetics were measured while patients were walking in the laboratory. The results were compared with an age-matched control group of healthy normal subjects. Patients were analyzed when grouped according to original diagnoses of rheumatoid or osteoarthritis. After total knee arthroplasty, patients with rheumatoid arthritis walked with a significantly lower magnitude peak adduction moment (force tending to thrust the knee into varus) about the knee than patients with osteoarthritis. The osteoarthritic group had an increased varus axial alignment when compared to the rheumatoid group. There was a strong correlation between postoperative varus alignment and the magnitude of the adduction moment. These results suggest that dynamic loading at the knee is greatly affected by static alignment of the joints in patients with total knee arthroplasty. In spite of the lower adduction moment during level walking and its associated effects on lower compressive loads at the knee, the patients with rheumatoid arthritis had a significantly higher radiolucency index. Thus, it appears that quality of bone stock may be a more important factor in determining prosthetic loosening than dynamic loading at the knee joint following total knee arthroplasty.
Brugioni
D J
DJ
Department of Orthopedic Surgery, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612.
Andriacchi
T P
TP
Galante
J O
JO
D001172:Arthritis, Rheumatoid / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000502:physiology; D007720:Knee Prosthesis; D008124:Locomotion / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009068:Movement; D010003:Osteoarthritis / Q000601:surgery*; D011859:Radiography; D013314:Stress, Mechanical; D013997:Time Factors