Load balance in total knee arthroplasty: an in vitro analysis.
BACKGROUND
One of the goals of total knee arthroplasty (TKA) is to balance the loads between the compartments of the knee. An instrumented load cell that measures compartment loads in real time is utilized to evaluate conventional, qualitative methods of achieving this balance.


METHODS
TKA was performed on 10 cadaveric knees. Prior to and after load balancing, compartment forces were measured at flexion angles of 0-90 degrees. Knees were randomly assigned into one of two groups, based upon whether or not the surgeons could visualize the load cell's output during balancing.


RESULTS
Prior to attempting load balance, there were significant differences between the medial and lateral compartment loads for all knees (p < 0.05). After attempting balance with the aid of the load cell, there was equal load balance at all angles studied. Without the aid of the load cell, balance was not consistently achieved at every angle.


CONCLUSIONS
Conventional load balancing techniques in TKA are not perfect.
El-Hawary
Ron
R
Division of Orthopaedic Surgery, IWK Health Centre, Dalhousie University, Halifax, Nova Scotia, Canada. ron.el-hawary@iwk.nshealth.ca
Roth
Sandra E
SE
King
Graham J W
GJ
Chess
David G
DG
Johnson
James A
JA
D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000379:methods*; D002102:Cadaver; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology* / Q000601:surgery*; D008297:Male; D015203:Reproducibility of Results; D012371:Robotics / Q000295:instrumentation / Q000379:methods*; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D025321:Surgery, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D013647:Task Performance and Analysis; D014159:Transducers; D016896:Treatment Outcome; D016474:Weight-Bearing