Kinematically aligned total knee arthroplasty limits high tibial forces, differences in tibial forces between compartments, and abnormal tibial contact kinematics during passive flexion

• Published in: Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA Vol. 26; no. 6; pp. 1589 - 1601
• Main Authors: Roth, Joshua D., Howell, Stephen M., Hull, Maury L.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2018; John Wiley & Sons, Inc
• Subjects: Aged; Aged, 80 and over; Alignment; Arthroplasty (knee); Arthroplasty, Replacement, Knee - adverse effects; Arthroplasty, Replacement, Knee - methods; Biomechanical Phenomena; Biomedical materials; Bone Malalignment - etiology; Bone Malalignment - physiopathology; Bone Malalignment - prevention & control; Cadaver; Cadavers; Compartments; Femoral components; Femur; Human performance; Humans; Joint surgery; Kinematics; Knee; Knee Joint - physiopathology; Knee Joint - surgery; Knee Prosthesis; Medical personnel; Medicine; Medicine & Public Health; Middle Aged; Orthopedics; Range of Motion, Articular; Recovery of function; Surgery; Surgical implants; Tibia - physiopathology; Tibia - surgery; Tibial components; Translation; Tibial force sensor; Kinematic alignment; Anterior sliding; Soft tissue balancing; Intra-articular load; Contact force imbalance; Tibiofemoral joint
• ISSN: 0942-2056; 1433-7347; 1433-7347
• DOI: 10.1007/s00167-017-4670-z

Purpose Following total knee arthroplasty (TKA), high tibial forces, large differences in tibial forces between the medial and lateral compartments, and anterior translation of the contact locations of the femoral component on the tibial component during passive flexion indicate abnormal knee function. Because the goal of kinematically aligned TKA is to restore native knee function without soft tissue release, the objectives were to determine how well kinematically aligned TKA limits high tibial forces, differences in tibial forces between compartments, and anterior translation of the contact locations of the femoral component on the tibial component during passive flexion. Methods Using cruciate retaining components, kinematically aligned TKA was performed on thirteen human cadaveric knee specimens with use of manual instruments without soft tissue release. The tibial forces and tibial contact locations were measured in both the medial and lateral compartments from 0° to 120° of passive flexion using a custom tibial force sensor. Results The average total tibial force (i.e. sum of medial + lateral) ranged from 5 to 116 N. The only significant average differences in tibial force between compartments occurred at 0° of flexion (29 N, p  = 0.0008). The contact locations in both compartments translated posteriorly in all thirteen kinematically aligned TKAs by an average of 14 mm ( p  < 0.0001) and 18 mm ( p  < 0.0001) in the medial and lateral compartments, respectively, from 0° to 120° of flexion. Conclusions After kinematically aligned TKA, average total tibial forces due to the soft tissue restraints were limited to 116 N, average differences in tibial forces between compartments were limited to 29 N, and a net posterior translation of the tibial contact locations was observed in all kinematically aligned TKAs during passive flexion from 0° to 120°, which are similar to what has been measured previously in native knees. While confirmation in vivo is warranted, these findings give surgeons who perform kinematically aligned TKA confidence that the alignment method and surgical technique limit high tibial forces, differences in tibial forces between compartments, and anterior translation of the tibial contact locations during passive flexion.