Evaluation of the wear performance of a polycarbonate-urethane acetabular component in a hip joint simulator and comparison with UHMWPE and cross-linked UHMWPE

Purpose of the study — to improve the two-dimensional planning of total hip joint arthroplasty to ensure precise positioning of the acetabular component in the deformed acetabulum. Materials and methods. Features of roentgenological anatomy of acetabulum and its coverage were studied on 1058 hip joint x-rays in the AP view in accordance with the procedure developed by the authors to define acetabular square — the site of standard positioning of a spherical femoral head in the acetabulum or of a hemispherical acetabular component. The method consisted of identifying the apex of “teardrop” figure; the most lateral points of the pelvic terminal line and roof of the acetabulum; superior part of the acetabular cavity; medial and inferior points of acetabular coverage, and building the sides of acetabular square — medial, inferior, lateral and superior boundary lines. Connection of “teardrop” apex and lateral point of the pelvic terminal line formed the medial side of acetabular square, and a perpendicular to that line drawn through the “teardrop” apex to its inferior side. The lateral side was drawn either through the intersection of the ascending diagonal line — bisector from the top of the “teardrop” figure with the contour of the acetabulum roof, or was a part of the projection of the most lateral point of the acetabular roof on the inferior side of the square. The superior side was a perpendicular connecting the intersection of the ascending diagonal and lateral bounding lines with the medial side of the acetabular square. The area of the deformed acetabular cavity located outside of the acetabular square was assessed as the acetabular defect. Results. Method of defining the acetabular square allowed to identify types of ratios between acetabular cavity and acetabular coverage in transverse (9 types) and longitudinal (7 types) direction. Combination of transverse ratio of acetabular cavity and coverage with longitudinal type allowed to define the options of acetabular deformities in two-dimensional view. The authors identified 25 types of acetabular deformities. Bone defects of acetabular walls were of the major importance among all anatomical features. Cranial defect of acetabulum was observed in 450 cases, medial wall defect — in 38 cases, defect including cranial and medial areas — in 7 cases. Conclusion. The method suggested by the authors to determine acetabular square and acetabular deformity variations allows to screen the anatomical features of the acetabulum during two-dimensional preoperative planning and to make an informed decision on the need to use other planning techniques. The type of acetabular deformity identified during preoperative planning allows to elaborate the indications for replacement of acetabular bone defects and/or resection of acetabular osteophytes.

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Treatment of an extensive acetabular defect in a patient with aseptic instability of a total hip arthroplasty

N.N. Priorov Journal of Traumatology and Orthopedics ◽

10.17816/vto202027360-66 ◽

2020 ◽

Vol 27 (3) ◽

pp. 60-66

Author(s):

Hovakim A. Aleksanyan ◽

Hamlet A. Chragyan ◽

Sergey V. Kagramanov ◽

Nikolay V. Zagorodniy

Keyword(s):

Acetabular Component ◽

Hip Joint ◽

Revision Arthroplasty ◽

Acetabular Defect ◽

Total Arthroplasty ◽

Total Endoprosthesis ◽

Reconstructive Operations ◽

Fresh Frozen ◽

Joint Revision ◽

The Right

The aim of the study is to demonstrate, using a clinical example, the possibility of treating a patient with a severe acetabular defect by performing a one-stage revision arthroplasty using an individual design. Materials and methods. A 45-year-old female patient was admitted with complaints of pain, limitation of movement in the right hip joint, and gait disturbance. From anamnesis at the age of 5 years, reconstructive operations of the hip joints were performed. In 1991, CITO performed primary total arthroplasty of the right hip joint with an endoprosthesis from ESKA Implants. In 1998, due to the instability of the acetabular component of the total endoprosthesis of the right hip joint, revision arthroplasty was performed, and the cup was placed with a cement fixation. In 2001, for left-sided dysplastic coxarthrosis, primary total arthroplasty of the left hip joint was performed. In 2012, due to the instability of the total endoprosthesis of the left hip joint, revision arthroplasty was performed using an ESI anti-protrusion ring (ENDOSERVICE) with a cement cup and a Zweimller-type femoral component; the femur defect was repaired using a fresh frozen cortical graft. In October 2019, instability of the total endoprosthesis of the right hip joint was revealed, for which revision endoprosthetics was performed using an individual acetabular component. Results. The HHS index before revision arthroplasty was 21 points, after 1 month after surgery 44 points, after 3 months after surgery 65, after 6 months 82. Quality of life was assessed according to the WOMAC scale: before surgery 73 points, after 1 month after surgery 54 points, after 3 months 31, after 6 months 15 points. At the time of the last consultation, the patient moves with a cane, lameness persists, associated with scar reconstruction and atrophy of the gluteal muscles. Conclusion. The use of individual structures allows to restore the support ability of the lower limb and the function of the hip joint in the case of an extensive defect of the pelvic bones of the pelvic discontinuity type.

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Biotribological behaviour of Vitamin E-blended highly cross-linked UHMWPE in a hip joint simulator

Industrial Lubrication and Tribology ◽

10.1108/ilt-09-2015-0130 ◽

2016 ◽

Vol 68 (5) ◽

pp. 548-553 ◽

Cited By ~ 2

Author(s):

Guomei Chen ◽

Zifeng Ni ◽

Shanhua Qian ◽

Yongwu Zhao

Keyword(s):

Wear Resistance ◽

Vitamin E ◽

Hip Joint ◽

Oxidative Degradation ◽

Test Environment ◽

Content Type ◽

Artificial Hip Joint ◽

Hip Simulator ◽

Directional Motion ◽

Hip Joint Simulator

Purpose The purposes of this paper are to investigate the biotribological behaviour of Vitamin E-blended highly cross-linked ultra-high molecular weight polyethylene (HXL-UHMWPE) under multi-directional motion by using a CUMT II artificial joint hip simulator and compare it with HXL-UHMWPE and conventional UHMWPE. Design/methodology/approach The biotribological behaviour of conventional, highly cross-linked and Vitamin E-blended highly cross-linked UHMWPE acetabular cups counterfaced with CoCrMo alloy femoral head under multi-directional motion were investigated by using CUMT-II artificial hip joint simulator for one-million walking cycles. The test environment was at 36.5 ± 0.5°C and 25 per cent bovine serum was used as lubricant. A Paul cycle load with a peak of 784 N was applied; the motion and loading were synchronized at 1 Hz. Findings The wear resistance of Vitamin E-blended highly cross-linked UHMWPE was significantly higher than that of highly cross-linked and conventional UHMWPE. The wear marks observed from the worn surface of UHMWPE were multi-directional, with no dominant wear direction. Only abrasion occurred on the surface of Vitamin E-blended highly cross-linked UHMWPE, while yielding and accumulated plastic flow processes occurred on the surface of conventional UHMWPE and flaking-like facture and abrasion occurred on the surface of highly cross-linked UHMWPE. Originality/value Besides the prevention of oxidative degradation, blending with Vitamin E can also reduce the incidence of fatigue crack occurred in the surface layer of HXL-UHMWPE samples. Therefore, the wear resistance of HXL-UHMWPE under multi-directional motion can be further enhanced by blending with Vitamin E.

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