Conventry Award Paper: Multicenter Determination of In Vivo Kinematics After Total Knee Arthroplasty

Abstract

A summation analysis of more than 70 individual kinematic studies involving normal knees and 33 different designs of total knee arthroplasty (TKA) was done with the objective of analyzing implant design variables that affect knee kinematics. Eight hundred eleven knees (733 subjects) were analyzed either during the stance phase of gait or a deep knee bend maneuver while under fluoroscopic surveillance. Fluoroscopic videotapes then were downloaded onto a workstation computer and anteroposterior (AP) femorotibial translational patterns were determined using an automated three-dimensional model fitting technique. The highest magnitude of translation was found in the normal and ACL-retaining TKA groups. Paradoxical anterior femoral translation during deep flexion was most commonly observed in PCL-retaining TKA. Substantial variability in kinematic patterns was observed in all groups. The least variability during gait was observed in mobile-bearing TKA designs, whereas posterior-stabilized TKA designs (fixed or mobile-bearing) showed the least variability during a deep knee bend. A medial pivot kinematic pattern was observed in only 55% of knees during deep knee flexion. Kinematic patterns of fixed versus mobile-bearing designs were similar with the exception of mobile-bearing TKA during gait in which femorotibial contact remained relatively stationary with minimal AP femorotibial translation.

Abnormal Axial Rotations in TKA Contribute to Reduced Weightbearing Flexion

“…In this study, we found that knees with greater than 15°of normal axial rotation obtain deeper flexion than those with more than 3°of reverse rotation. It has been hypothesized that this reverse rotation pattern may limit TKA flexion as a result of the anteriorization of the lateral condyle [3]. Additionally, we found that knees with an ending normal axial rotation of greater than 3°obtained deeper flexion than those knees that had less normal-ending axial rotation or reverse-ending axial rotation.…”

In Vivo Kinematics after a Cruciate-substituting TKA

“…Numerous kinematic analyses of the normal knee have documented greater mean posterior motion of the lateral condyle relative to the medial condyle, leading to a mean internal rotation of the tibia with progressive knee flexion [9,15,23,25,27,29]. Komistek et al reported the lateral condyle achieved more posterior motion than the medial condyle, 19.2 mm and 3.4 mm, respectively, with increasing knee flexion during a deep knee bend [25].…”

“…With increasing knee flexion, the normal knee reportedly experiences more posterior motion of the lateral condyle leading to internal rotation of the tibia with respect to the femur [18,22,25]. In contrast to the normal knee, in vivo kinematic analyses suggest subjects undergoing TKA often experience a motion pattern opposite the normal knee where the condyles slide in the anterior direction with increasing knee flexion [2,8,9,24,28,31,[34][35][36][37]. Also, in vivo kinematic studies involving patients undergoing TKA have documented reverse rotational patterns [2,10] and lateral condylar liftoff [13,21,34,37].…”

“…However, measurement in weightbearing conditions typically reduces the observed ROM [11]. PCR and PS TKAs have similar kinematic patterns in early flexion activities such as gait [9,10].…”

CORR Insights®: Higher Frequency of Reoperation With a New Bicruciate-retaining Total Knee Arthroplasty

“…These parameters should include early failure rates, patient reported outcomes, radiographic findings, and ultimately long-term survival and revision rates. These parameters are a part of any long-term registry with level three and four data already established in many advanced countries and gaining momentum in the United States through the American Joint Replacement Registry [2,4].…”