COMPREHENSIVE GAIT ANALYSIS IN POSTERIOR-STABILIZED KNEE ARTHROPLASTY

Sixteen patients implanted with a posterior-stabilized prosthesis (Ins all-Burstein PS II, Zimmer, Warsaw, IN) and 32 age-matched control sub jects were evaluated by isokinetic muscle testing and comprehensive ga it analysis at a mean 46 months following the index arthroplasty. The contralateral knee was normal in 13 patients and an asymptomatic total knee arthroplasty in 3 patients. No significant differences (P > .05) were found between the study and control groups in spatiotemporal gai t parameters nor were there isokinetic strength deficits. A prolonged firing of the vastus medialis was observed in some patients. Knee rang e of motion during level walking and stair descent was decreased signi ficantly (P < .05) in the study group. There was no significant differ ence for knee range of motion between the study and control groups dur ing stair ascent. Spatiotemporal gait parameters in the total knee art hroplasty patients show no significant differences from the control su bject at nearly 4 years after surgery. However, other gait abnormaliti es are present and cannot be accounted for on the basis of muscle weak ness, abnormal phasic muscle activity, or inadequate knee range of mot ion. With reference to historic control subjects, the persistent gait abnormalities of patients implanted with posterior-stabilized prosthes es (posterior cruciate substituting) are comparable to those of patien ts implanted with cruciate-retaining prostheses and superior to crucia te sacrificing prostheses.