The effect of patellar thickness on intraoperative knee flexion and patellar tracking in total knee arthroplasty.
We designed a simple IRB-approved study to evaluate the intraoperative effect of patellar thickness on knee flexion and patellar tracking during total knee arthroplasty. Routine PCL-retaining total knee arthroplasty was performed in 31 consecutive knees. With clinical balance and congruent patella tracking established, custom trial patellar components that were thicker than the standard trial by 2-mm increments (2-8 mm) were sequentially placed and trialed. Passive flexion was recorded to the nearest 5 degrees with an intraoperative goniometer and gross mechanics of patellofemoral tracking were visually assessed. On average, passive knee flexion decreased 3 degrees for every 2-mm increment of patellar thickness. Furthermore, for the knee system used in this study, increased patellar thickness had no gross effect on patellar subluxation or tilt.
Bengs
Benjamin C
BC
Department of Orthopaedic Surgery, Harvard Combined Orthopaedic Surgery Residency, Massachusetts General Hospital, GRB 6, Boston, MA 02114, USA.
Scott
Richard D
RD
D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology / Q000601:surgery*; D008297:Male; D010329:Patella / Q000502:physiology / Q000601:surgery*; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D016896:Treatment Outcome