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Bone & Joint Research
Vol. 9, Issue 7 | Pages 360 - 367
1 Jul 2020
Kawahara S Hara T Sato T Kitade K Shimoto T Nakamura T Mawatari T Higaki H Nakashima Y

Aims

Appropriate acetabular component placement has been proposed for prevention of postoperative dislocation in total hip arthroplasty (THA). Manual placements often cause outliers in spite of attempts to insert the component within the intended safe zone; therefore, some surgeons routinely evaluate intraoperative pelvic radiographs to exclude excessive acetabular component malposition. However, their evaluation is often ambiguous in case of the tilted or rotated pelvic position. The purpose of this study was to develop the computational analysis to digitalize the acetabular component orientation regardless of the pelvic tilt or rotation.

Methods

Intraoperative pelvic radiographs of 50 patients who underwent THA were collected retrospectively. The 3D pelvic bone model and the acetabular component were image-matched to the intraoperative pelvic radiograph. The radiological anteversion (RA) and radiological inclination (RI) of the acetabular component were calculated and those measurement errors from the postoperative CT data were compared relative to those of the 2D measurements. In addition, the intra- and interobserver differences of the image-matching analysis were evaluated.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_8 | Pages 25 - 25
1 May 2016
Hamai S Nakashima Y Hara D Higaki H Ikebe S Shimoto T Iwamoto Y
Full Access

INTRODUCTION

Golf is considered low-impact sport, but concerns exist about whether golf swing can be performed in safe manner after THA. The purpose of this study was to clarify dynamic hip kinematics during golf swing after THA using image-matching techniques.

METHODS

This study group consisted of eight right-handed recreational golfers with 10 primary THAs. Each operation was performed using a posterolateral approach with combined anteversion technique. Nine of ten polyethylene liners used had elevated portion of 15°. Continuous radiographic images of five trail and five lead hips during golf swing were recorded using a flat panel X-ray detector (Fig. 1) and analyzed using image-matching techniques (Fig. 2). The relative distance between the center of cup and femoral head and the minimum liner-to-stem distance were measured using a CAD software program. The cup inclination, cup anteversion, and stem anteversion were measured in postoperative CT data. Hip kinematics, orientation of components, and cup-head distance were compared between patients with and without liner-to-stem contact by Mann-Whitney U test.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_2 | Pages 25 - 25
1 Jan 2016
Hamai S Okazaki K Mizu-uchi H Shimoto T Higaki H Iwamoto Y
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Introduction

Controversy still exists as to whether total knee arthroplasty (TKA) provides reproducible knee kinematics during activities. In this study, we evaluated the in vivokinematics of stair-climbing after TKA using a 3D-to-2D model-to-image registration technique.

Patients and Methods

A total of twenty four knees in nineteen patients following cruciate-retaining (CR) or posterior-stabilized (PS) TKA were randomly included in the study. The twenty-four knees included 22 female knees and 2 male knees in patients aged 73 years. The pre-operative diagnosis was osteoarthritis in 22 knees and rheumatoid arthritis in 2 knees. The average follow-up period after surgery was 29 months, and average post-operative knee extension/flexion angle was 2°/121°. The average knee score was 93 and the average functional score was 77. Continuous sagittal radiological images were obtained during stair-climbing for each patient using a large flat panel detector. Anteroposterior (AP) tibiofemoral position, implant flexion, and axial rotation angles were determined in three dimensions using a 3D-to-2D model-to-image registration technique. In CR TKA, the minimum distances between the femoral trochlea and the intercondylar eminence of the tibial insert were measured using a CAD software program. In PS TKA, the minimum distances between the femoral cam and the posterior aspect of the tibial post and between the femoral trochlea and the anterior aspect of the tibial post were measured.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_2 | Pages 29 - 29
1 Jan 2016
Hara D Nakashima Y Hamai S Higaki H Shimoto T Ikebe S Hirata M Kanazawa M Kohno Y Iwamoto Y
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Introduction

3D-to-2D model registration technique has been used for evaluating 3D kinematics from 3D surface models of the prostheses or bones and radiographic image sequences. However, no studies have employed these techniques to evaluate in vivo hip kinematics under dynamic weight-bearing conditions. The purposes of this study were to evaluate kinematics of healthy hips and also hips with osteoarthritis (OA) prior to total hip arthroplasty (THA) during four different weight-bearing activities using 3D-to-2D model-to-image registration technique.

Measurement

Dynamic hip kinematics during gait, squatting, chair-rising, and twisting were analyzed for six healthy subjects and eleven patients with osteoarthritis (OA). Continuous anteroposterior radiographic images were recorded using a flat panel X-ray detector (Fig. 1), and each hip joint was scanned by computed tomography (CT). The 3D positions and orientations of the pelvis and femur in movement cycle were determined using a 3D-to-2D model-to-image registration technique. A matching algorithm maximizing correlations between density-based digitally reconstructed radiographs from CT data and the radiographic images was applied (Fig. 2). The relative positions and orientations of the pelvis with respect to the world coordinate systems were defined as pelvic movements (anterior-posterior tilt, contralateral-ipsilateral rotation, Fig. 3b and c), and those of the femur with respect to the world coordinate systems were defined as femoral movements (flexion-extension, internal-external rotation, Fig. 3d). We also defined the relative positions and orientations of the femur for the pelvis as hip movements (flexion-extension, internal-external rotation, Fig. 3e and f).


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 447 - 447
1 Dec 2013
Nakanishi Y Hidehiko H Miura H Shiraishi Y Shimoto T Umeno T Mizuta H Iwamoto Y
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An ultra-high molecular weight polyethylene (UHMWPE) is widely used as bearing material in artificial joints, however, UHMWPE wear particles are considered to be a major factor in long-term osteolysis and loosening of implants. The wear particles activate macrophages, which release cytokines, stimulating osteoclasts, which results in bone resorption. The biological activity of the wear debris is dependent on the volume and size of the particles produced. Many researchers reported that the volume and size of particles were critical factors in macrophage activation, which particles in the size range of 0.1–1 mm being the most biological active.

To minimize the amount of wear of UHMWPE and to enlarge the size of UHMWPE wear particle, a nano-level surface textured on Co-Cr-Mo alloy as a counterface material was invented (Figure 1). Although the generally-used surface for a conventional artificial joint has 10 nm roughness (G-1), the nano-level surface has a superfine surface of 1 nm with groove and dimples against the bearing area. The existence probability of groove or dimples, and their surface waviness were adjusted (P-1, 2, 3, 4 and W-1, 2).

Pin-on-disc wear tester capable of multidirectional motions was used to verify that the nano-textured surface is the most appropriate for artificial joint. UHMWPE pin with an average molecular weight of 6.0 million was placed in contact with the disc and the contact pressure was 6.0 MPa. The disc and pin were lubricated by a water-based liquid containing the principal constituents of natural synovial fluid. Sliding speed of 12.12 mm/s had been applied for total sliding distance of 15 km.

The nano-textured surfaces reduced the amount of UHMWPE wear, this would ensure the long-term durability of artificial joint (Figure 2). The wear particles isolated from lubricating liquid were divided broadly into two categories; one is “simple type” and the other is “complicated type”. The lengths in a longitudinal direction (Ll) and its orthogonal direction (Ls) for each particles (>150) were measured, and the each aspect ratio (= Ll/Ls) was calculated. No significant difference was found in the ratio between simple type and complicated type, and in the distributions of aspect ratios. However, the distributions of Ll, which means the size of UHMWPE wear particle, were dramatically changed by using the nano-textured surface (Figure 3). These results suggest that the nano-textured surface does not change the morphological aspect of UHMWPE particle but enlarges the size of UHMWPE particle.

Cells (RAW264.7, blood, Mouse) were cultured with the particles in supplemented Dulbecco's modified Eagle's medium for 24 h in an atmosphere of 5% CO2 in air at 37 degrees C, and the quantitative PCR was performed for genetic expression of IL-6. The wear debris generated on the nano-textured surface inhibited the genetic expression of IL-6, which does not induce the tissue reaction and joint loosening.


The Journal of Bone & Joint Surgery British Volume
Vol. 94-B, Issue 1 | Pages 56 - 61
1 Jan 2012
Kawahara S Matsuda S Fukagawa S Mitsuyasu H Nakahara H Higaki H Shimoto T Iwamoto Y

In posterior stabilised total knee replacement (TKR) a larger femoral component is sometimes selected to manage the increased flexion gap caused by resection of the posterior cruciate ligament. However, concerns remain regarding the adverse effect of the increased anteroposterior dimensions of the femoral component on the patellofemoral (PF) joint. Meanwhile, the gender-specific femoral component has a narrower and thinner anterior flange and is expected to reduce the PF contact force. PF contact forces were measured at 90°, 120°, 130° and 140° of flexion using the NexGen Legacy Posterior Stabilized (LPS)-Flex Fixed Bearing Knee system using Standard, Upsized and Gender femoral components during TKR. Increasing the size of the femoral component significantly increased mean PF forces at 120°, 130° and 140° of flexion (p = 0.005, p < 0.001 and p < 0.001, respectively). No difference was found in contact force between the Gender and the Standard components. Among the patients who had overhang of the Standard component, mean contact forces with the Gender component were slightly lower than those of the Standard component, but no statistical difference was found at 90°, 120°, 130° or 140° of flexion (p = 0.689, 0.615, 0.253 and 0.248, respectively).

Upsized femoral components would increase PF forces in deep knee flexion. Gender-specific implants would not reduce PF forces.


The Journal of Bone & Joint Surgery British Volume
Vol. 90-B, Issue 9 | Pages 1180 - 1185
1 Sep 2008
Hamai S Miura H Higaki H Shimoto T Matsuda S Iwamoto Y

Mechanical failure because of wear or fracture of the polyethylene tibial post in posteriorly-stabilised total knee replacements has been extensively described. In this study of 12 patients with a clinically and radiologically successful NexGen LPS posteriorly-stabilised prosthesis impingement of the anterior tibial post was evaluated in vivo in three dimensions during gait using radiologically-based image-matching techniques.

Impingement was observed in all images of the patients during the stance phase, although the NexGen LPS was designed to accommodate 14° of hyperextension of the component before impingement occurred. Impingement arises as a result of posterior translation of the femur during the stance phase. Further attention must therefore be given to the configuration of the anterior portion of the femoral component and the polyethylene post when designing posteriorly-stabilised total knee replacements.