The biomechanical effect of different posterior tibial slopes on the tibiofemoral joint after posterior-stabilized total knee arthroplasty

Abstract

Background Different posterior tibial slopes (PTS) after posterior-stabilized total knee arthroplasty (PS-TKA) may lead to different biomechanical characteristics of knee joint. This cadaveric study was designed to investigate the tibiofemoral kinematics and contact pressures after PS-TKA with different PTS. Methods Nine human cadaveric knee specimens were used for PS-TKA with the PTS of 3°, 6°, and 9°. The tibiofemoral kinematics and contact pressures were measured during knee flexion angle changing from 0 to 120° (with an increment of 10°) with an axial load of 1000 N at each angle. Results The root mean square (RMS) of the tibiofemoral contact area and the mean and peak contact pressures during knee flexion were 586.2 mm 2 , 1.85 MPa, and 5.39 MPa before TKA and changed to 130.2 mm 2 , 7.56 MPa, and 17.98 MPa after TKA, respectively. Larger contact area and smaller mean and peak contact pressures were found in the joints with the larger PTS after TKA. The RMS differences of femoral rotation before and after TKA were more than 9.9°. The posterior translation of the lateral condyle with larger PTS was more than that with smaller PTS, while overall, the RMS differences before and after TKA were more than 11.4 mm. Conclusion After TKA, the tibiofemoral contact area is reduced, and the contact pressure is increased greatly. Approximately 80% of the femoral rotation is lost, and only about 60% of the femoral translation of lateral condyle is recovered. TKA with larger PTS results in more posterior femoral translation, larger contact area, and smaller contact pressure, indicating that with caution, it may be beneficial to properly increase PTS for PS-TKA.

Validation of a novel finite-element model for evaluating patellofemoral forces and stress during squatting after posterior-stabilized total knee arthroplasty

“…The initial step of the computer validation focuses on the tibiofemoral joint's loads and kinematics, similar to the in vivo or experimental conditions observed after implantation of posteriorstabilized TKA: presence of posterior femoral roll-back of several millimeters without paradoxical anterior translation, limited lateral lift-off of femoral condyles during flexion [22,23]. In our simulation, the tibiofemoral contact forces, their distribution between the medial and lateral compartments (about 60% vs. 40%), along with the instant of post-cam contact (typically reported to be between 60 • and 75 • flexion) were consistent with several published studies [22,24,25].…”

Tibio‐Femoral Contact Force Distribution of Knee Before and After Total Knee Arthroplasty: Combined Finite Element and Gait Analysis

“…Osteotomy was performed in accordance with the recommended standard of the prosthesis. 19 Both patients were able to walk independently without assistance before and after TKA.…”

“…Femoral intramedullary positioning and tibial extramedullary positioning were performed. Osteotomy was performed in accordance with the recommended standard of the prosthesis 19 . Both patients were able to walk independently without assistance before and after TKA.…”

The effect of gender, age, and body mass index on the medial and lateral posterior tibial slopes: a magnetic resonance imaging study

“…The PTS affects knee joint stability, biomechanics, and PCL tension after TKA [ 27 , 32 ], and a reduced PTS can lead to abnormal femoral rollback, polyethylene wear, and postoperative stiffness [ 32 ]. Moreover, TKA with excessive PTS results in an increased contact area, smaller contact pressure, and posterior femoral translation [ 33 ]. Therefore, the PTS greatly influences the clinical outcomes of TKA.…”