Background The purpose of this study was to compare radiological features between high tibial osteotomy (HTO) and tibial condylar valgus osteotomy (TCVO), in order to define the radiological indication criteria for TCVO. Methods Thirty-two cases involving 35 knees that had undergone HTO and the same number that had undergone TCVO for knee osteoarthritis were retrospectively evaluated. Characteristics of both groups did not differ significantly. Lower limb alignment, bone morphology, joint congruity, and joint instability were measured in standing full-length leg and knee radiographs obtained before and after surgery. Results Radiological features in the TCVO group included greater frequencies of advanced knee OA grade, varus lower limb malalignment, depression of the medial tibial plateau, and varus-valgus joint instability compared to the HTO group before surgery. However, tibial morphology, alignment of the lower limb, and joint instability improved to comparable levels after surgery in both groups. Conclusions TCVO appears preferable in cases with advanced knee OA, destroyed or inclined medial tibial plateau, widened and subluxated lateral joint, and high varus-valgus joint instability.

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.

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