The Effect of Femoral Cutting Jig Design on Restoration of Femoral Offset in Posterior-Referenced Total Knee Arthroplasty.

The Effect of Femoral Cutting Jig Design on Restoration of Femoral Offset in Posterior-Referenced Total Knee Arthroplasty. Orthopedics. 2019 Sep 10;:1-7 Authors: Coyle RM, Bas MA, Rodriguez JA, Hepinstall MS Abstract Femoral component sizing and rotation in total knee arthroplasty (TKA) affects patellofemoral tracking and tibiofemoral mechanics. Posterior referencing is said to optimize restoration of posterior condylar offset. However, it typically allows the surgeon to select 3° to 5° of external rotation to the posterior condylar axis, inevitably changing the offset of one or both condyles. The axis about which external rotation occurs varies between the jigs of various TKA systems. The location of this axis can result in a medial, central, or lateral reference point for posterior offset restoration. Variations in jig design will result in varying posterior offset changes at the same jig setting, with differential effects on balance between the flexion and extension gaps. Using identical Sawbones in a controlled laboratory setting, 9 TKA instrumentation systems were examined. Two systems referenced medially, 1 referenced laterally, and 6 referenced centrally. The authors measured distal and posterior resections in both 3° and 5° of external rotation to the posterior condylar axis. They calculated changes in both distal and posterior joint lines using resection measurements and implant specifications. Posterior resection thickn...
Source: Orthopedics - Category: Orthopaedics Authors: Tags: Orthopedics Source Type: research