Limits...
Kinematic analysis of a posterior-stabilized knee prosthesis.

Zhao ZX, Wen L, Qu TB, Hou LL, Xiang D, Bin J - Chin. Med. J. (2015)

Bottom Line: Computed tomography and magnetic resonance imaging scans of a healthy, anticorrosive female cadaver were used to establish a model of the entire lower limbs, including the femur, tibia, patella, fibula, distal femur cartilage, and medial and lateral menisci, as well as the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments.The displacement of the medial/lateral femur and the internal rotation angle of the tibia were analyzed during 0-135° flexion.Both the output data trends and the measured values derived from the normal knee's kinematics model were very close to the results reported in a previous in vivo study, suggesting that this model can be used for further analyses.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopedics, Beijing Chao Yang Hospital, Capital Medical University, Beijing 100020, China.

ABSTRACT

Background: The goal of total knee arthroplasty (TKA) is to restore knee kinematics. Knee prosthesis design plays a very important role in successful restoration. Here, kinematics models of normal and prosthetic knees were created and validated using previously published data.

Methods: Computed tomography and magnetic resonance imaging scans of a healthy, anticorrosive female cadaver were used to establish a model of the entire lower limbs, including the femur, tibia, patella, fibula, distal femur cartilage, and medial and lateral menisci, as well as the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments. The data from the three-dimensional models of the normal knee joint and a posterior-stabilized (PS) knee prosthesis were imported into finite element analysis software to create the final kinematic model of the TKA prosthesis, which was then validated by comparison with a previous study. The displacement of the medial/lateral femur and the internal rotation angle of the tibia were analyzed during 0-135° flexion.

Results: Both the output data trends and the measured values derived from the normal knee's kinematics model were very close to the results reported in a previous in vivo study, suggesting that this model can be used for further analyses. The PS knee prosthesis underwent an abnormal forward displacement compared with the normal knee and has insufficient, or insufficiently aggressive, "rollback" compared with the lateral femur of the normal knee. In addition, a certain degree of reverse rotation occurs during flexion of the PS knee prosthesis.

Conclusions: There were still several differences between the kinematics of the PS knee prosthesis and a normal knee, suggesting room for improving the design of the PS knee prosthesis. The abnormal kinematics during early flexion shows that the design of the articular surface played a vital role in improving the kinematics of the PS knee prosthesis.

Show MeSH

Related in: MedlinePlus

(a) The three-dimensional (3D) bone model of lower limb. (b) The 3D model of cartilage and meniscus. (c) The 3D model of normal knee joint.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4837841&req=5

Figure 1: (a) The three-dimensional (3D) bone model of lower limb. (b) The 3D model of cartilage and meniscus. (c) The 3D model of normal knee joint.

Mentions: The CT images were used to establish a model of the entire lower limbs, including the femur, tibia, patella, and fibula. The normal attenuation coefficient range of human skeletal bone is 226–1701 Hu; this threshold range was chosen to establish the mask in the setting of Mimics 13.0. The different colors indicate the masks of different bone models. Manual division and repair were applied to the scanned images for processing. First, a partial division was made for the scanned images of the connection structures among the femur, tibia, and fibula. Next, the “region growth” function of Mimics was used to further divide the selected image, and different bone structures were separated. Finally, the “three-dimensional (3D) calculation” function of Mimics was used to reconstruct each individual mask. After this process, the 3D bone structures were clearly visualized [Figure 1a].


Kinematic analysis of a posterior-stabilized knee prosthesis.

Zhao ZX, Wen L, Qu TB, Hou LL, Xiang D, Bin J - Chin. Med. J. (2015)

(a) The three-dimensional (3D) bone model of lower limb. (b) The 3D model of cartilage and meniscus. (c) The 3D model of normal knee joint.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837841&req=5

Figure 1: (a) The three-dimensional (3D) bone model of lower limb. (b) The 3D model of cartilage and meniscus. (c) The 3D model of normal knee joint.
Mentions: The CT images were used to establish a model of the entire lower limbs, including the femur, tibia, patella, and fibula. The normal attenuation coefficient range of human skeletal bone is 226–1701 Hu; this threshold range was chosen to establish the mask in the setting of Mimics 13.0. The different colors indicate the masks of different bone models. Manual division and repair were applied to the scanned images for processing. First, a partial division was made for the scanned images of the connection structures among the femur, tibia, and fibula. Next, the “region growth” function of Mimics was used to further divide the selected image, and different bone structures were separated. Finally, the “three-dimensional (3D) calculation” function of Mimics was used to reconstruct each individual mask. After this process, the 3D bone structures were clearly visualized [Figure 1a].

Bottom Line: Computed tomography and magnetic resonance imaging scans of a healthy, anticorrosive female cadaver were used to establish a model of the entire lower limbs, including the femur, tibia, patella, fibula, distal femur cartilage, and medial and lateral menisci, as well as the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments.The displacement of the medial/lateral femur and the internal rotation angle of the tibia were analyzed during 0-135° flexion.Both the output data trends and the measured values derived from the normal knee's kinematics model were very close to the results reported in a previous in vivo study, suggesting that this model can be used for further analyses.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopedics, Beijing Chao Yang Hospital, Capital Medical University, Beijing 100020, China.

ABSTRACT

Background: The goal of total knee arthroplasty (TKA) is to restore knee kinematics. Knee prosthesis design plays a very important role in successful restoration. Here, kinematics models of normal and prosthetic knees were created and validated using previously published data.

Methods: Computed tomography and magnetic resonance imaging scans of a healthy, anticorrosive female cadaver were used to establish a model of the entire lower limbs, including the femur, tibia, patella, fibula, distal femur cartilage, and medial and lateral menisci, as well as the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments. The data from the three-dimensional models of the normal knee joint and a posterior-stabilized (PS) knee prosthesis were imported into finite element analysis software to create the final kinematic model of the TKA prosthesis, which was then validated by comparison with a previous study. The displacement of the medial/lateral femur and the internal rotation angle of the tibia were analyzed during 0-135° flexion.

Results: Both the output data trends and the measured values derived from the normal knee's kinematics model were very close to the results reported in a previous in vivo study, suggesting that this model can be used for further analyses. The PS knee prosthesis underwent an abnormal forward displacement compared with the normal knee and has insufficient, or insufficiently aggressive, "rollback" compared with the lateral femur of the normal knee. In addition, a certain degree of reverse rotation occurs during flexion of the PS knee prosthesis.

Conclusions: There were still several differences between the kinematics of the PS knee prosthesis and a normal knee, suggesting room for improving the design of the PS knee prosthesis. The abnormal kinematics during early flexion shows that the design of the articular surface played a vital role in improving the kinematics of the PS knee prosthesis.

Show MeSH
Related in: MedlinePlus