- TKR Menu
- Joint Line Position:
- Posterior Stabilized Prosthesis:
- Function of Posterior Cruciate Ligament: (see PCL)
- as the knee flexes, eccentric postion of the PCL femoral orgin prodecues a tensile force in the ligament;
- because of nonconforming low friction articlation, this tensile force is converted into a translatory force, shifting tibia forward (or forcing femur to roll back);
- posterior clearance is increased, permitting greater flexion w/o impingment;
- moment arm of quadriceps is incr by 20 to 30%;
- PCL Retaining Prosthesis:
- retention of PCL may allow more normal knee function in climbing stairs;
- retention of the PCL requires that prosthetic kinematics closely match that of the normal knee;
- posterior cruciate retention along with minimal constraint on tibial component enables normal roll back of the femur on tibia with knee flexion;
- this roll back allows for increased quadriceps lever arm & more efficient use of extensor musculature, permiting more normal stair climbing;
- retention of PCL requires that slope of replaced femoral condyles closely match that of the native condyles;
- excessive posterior condyle thickness prevents full flexion;
- insufficient thickness results in laxity of ligament & failure to achieve roll back;
- advantages of PCL retention:
- maintenance of ligament's proprioceptive abilities;
- maintenance of load transfers by the PCL;
- allows stress sharing, so that stress is taken on bone cement interface;
- AP stability;
- adequate exposure of proximal tibia may not be possible w/ PCL retention;
- difficult to balance collateral ligament;
- will increase joint reactive forces;
- increased polyethylene wear;
- excessive proximal tibial resection may jeopardize the PCL insertion, in which case a posterior stabilized prosthesis will be required;
- increased need for soft tissue balancing and soft tissue releases
- ref: Correction of axial and rotational alignment after medial and lateral releases during balanced gap TKA. A clinical study of 54 patients.
- malposition of joint line
- tends to decrease knee flexion;
- attempts to recreate joint line at its preop level may necessitate excessive proximal tibial bone resection to avoid use of an excessively thin polyethylene component
Posterior cruciate ligament strain biomechanics in total knee arthroplasty.
Posterior cruciate condylar total knee arthroplasty. Average 11-year follow-up evaluation.
Functional comparison of posterior cruciate-retained versus cruciate-sacrificed total knee arthroplasty.
Posterior cruciate condylar total knee arthroplasty. Five-year results.
Two- to four-year results of posterior cruciate-sparing condylar total knee arthance of radiolucent lines.
Twelve years' experience with posterior cruciate-retaining total knee arthroplasty.
The posterior cruciate ligament in total knee surgery. Save, sacrifice, or substitute.
Proprioception, Kinesthesia, and Balance After Total Knee Arthroplasty with Cruciate-Retaining and Posterior Stabilized Prostheses.
Increased Long-Term Survival of Posterior Cruciate-Retaining Versus Posterior Cruciate-Stabilizing Total Knee Replacements
Original Text by Clifford R. Wheeless, III, MD.
Last updated by Clifford R. Wheeless, III, MD on Sunday, February 3, 2013 8:12 pm