Takeshi Miyaji

Comparison of in vivo Kinematics in Primary Medial Osteoarthritic and ACL Deficient Knees during a Leg Press

Background: Primary knee osteoarthritis (OA) is a progressive and disabling disorder affecting up to 13% of individuals aged 65 years and older. Anterior cruciate ligament deficiency (ACLD) is known to be a major precursor of early development of degenerative changes in the knee. There is a possibility of becoming a help of the disease process clarification of knee OA appearance of disease by investigating the relativity of knee OA and ACLD. Methods: Fifteen OA, 9 ACLD, and 9 uninvolved knees were enrolled. In vivo knee kinematics was obtained using a 3D-to-2D registration technique utilizing CT-based bone models and lateral fluoroscopy during a leg press activity. Results: The OA knees were in greater external rotation than the uninvolved and ACLD knees, while there were no differences between the uninvolved and ACLD knees. Reduced screw home motion was observed in OA knees. Knee kinematics in the earlier stages of knee OA appeared to change at mid flexion angles, while in the later stages at all flexion angles. Conclusions: The OA knees showed grater abnormal kinematics as compared than the ACLD at small load of a leg press device. Level of Evidence: Prognostic Level III.

Double-bundle anterior cruciate ligament reconstruction improves tibial rotational instability: analysis of squatting motion using a 2D/3D registration technique

BackgroundThe anterior cruciate ligament-deficient (ACLD) knee requires appropriate treatment for the patient to return to sports. The purpose of this study was to clarify the kinematics of the anterior cruciate ligament-deficient knee in squatting motion before and after double-bundle anterior cruciate ligament reconstruction (DB-ACLR) using a 2D/3D registration technique.MethodsThe subjects of this study were 10 men with confirmed unilateral ACL rupture who underwent DB-ACLR. Computed tomography (CT) of the knee joints was performed before DB-ACLR. Fluoroscopic imaging of the knee motion in squatting before and after DB-ACLR was also performed. The 2D/3D registration technique is a method of calculating positional relationships by projecting the 3D bone model created from the CT data onto the image extracted from the fluoroscopic images. The tibial anteroposterior (AP) and rotational positions were analyzed with reference to the femur.ResultsThe tibial AP position of the ACLD knees was significantly anterior to the contralateral knees (p = 0.015). The tibial rotational position of the ACLD knees was significantly internally rotated compared to the contralateral knees (p < 0.001). Both tibial AP and rotational positions improved after DB-ACLR (p < 0.001), with no significant differences compared to the contralateral knees.ConclusionDB-ACLR improved not only tibial AP instability but also tibial rotational instability at knee flexion with weight-bearing. DB-ACLR appears to be a useful technique for normalizing the knee joint kinematics of ACLD knees.