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Bone & Joint Research
Vol. 9, Issue 11 | Pages 761 - 767
1 Nov 2020
Hada M Mizu-uchi H Okazaki K Murakami K Kaneko T Higaki H Nakashima Y

Aims

This study aims to investigate the effects of posterior tibial slope (PTS) on knee kinematics involved in the post-cam mechanism in bi-cruciate stabilized (BCS) total knee arthroplasty (TKA) using computer simulation.

Methods

In total, 11 different PTS (0° to 10°) values were simulated to evaluate the effect of PTS on anterior post-cam contact conditions and knee kinematics in BCS TKA during weight-bearing stair climbing (from 86° to 6° of knee flexion). Knee kinematics were expressed as the lowest points of the medial and lateral femoral condyles on the surface of the tibial insert, and the anteroposterior translation of the femoral component relative to the tibial insert.


Bone & Joint Research
Vol. 4, Issue 8 | Pages 128 - 133
1 Aug 2015
Kuwashima U Okazaki K Tashiro Y Mizu-Uchi H Hamai S Okamoto S Murakami K Iwamoto Y

Objectives

Because there have been no standard methods to determine pre-operatively the thickness of resection of the proximal tibia in unicompartmental knee arthroplasty (UKA), information about the relationship between the change of limb alignment and the joint line elevation would be useful for pre-operative planning. The purpose of this study was to clarify the correlation between the change of limb alignment and the change of joint line height at the medial compartment after UKA.

Methods

A consecutive series of 42 medial UKAs was reviewed retrospectively. These patients were assessed radiographically both pre- and post-operatively with standing anteroposterior radiographs. The thickness of bone resection at the proximal tibia and the distal femur was measured radiographically. The relationship between the change of femorotibial angle (δFTA) and the change of joint line height, was analysed.


The Journal of Bone & Joint Surgery British Volume
Vol. 90-B, Issue 8 | Pages 1025 - 1031
1 Aug 2008
Mizu-uchi H Matsuda S Miura H Okazaki K Akasaki Y Iwamoto Y

We compared the alignment of 39 total knee replacements implanted using the conventional alignment guide system with 37 implanted using a CT-based navigation system, performed by a single surgeon. The knees were evaluated using full-length weight-bearing anteroposterior radiographs, lateral radiographs and CT scans.

The mean hip-knee-ankle angle, coronal femoral component angle and coronal tibial component angle were 181.8° (174.2° to 188.3°), 88.5° (84.0° to 91.8°) and 89.7° (86.3° to 95.1°), respectively for the conventional group and 180.8° (178.2° to 185.1°), 89.3° (85.8° to 92.0°) and 89.9° (88.0° to 93.0°), respectively for the navigated group.

The mean sagittal femoral component angle was 85.5° (80.6° to 92.8°) for the conventional group and 89.6° (85.5° to 94.0°) for the navigated group.

The mean rotational femoral and tibial component angles were −0.7° (−8.8° to 9.8°) and −3.3° (−16.8° to 5.8°) for the conventional group and −0.6° (−3.5° to 3.0°) and 0.3° (−5.3° to 7.7°) for the navigated group.

The ideal angles of all alignments in the navigated group were obtained at significantly higher rates than in the conventional group. Our results demonstrated significant improvements in component positioning with a CT-based navigation system, especially with respect to rotational alignment.