Toru Ichiseki

Minimum ten-year results of a porous acetabular component for Crowe I to III hip dysplasia using an elevated hip center.

We conducted a retrospective study of the placement of porous-coated acetabular components using screws at more than 20 mm above the teardrop without structural bone graft for dysplastic hips to determine long-term outcome. Thirty hips (29 patients) were monitored for a mean of 15.2 years (range, 10.4-18.3 years) after surgery. Compared with 12 contralateral normal hips, the distance of the hip center from the teardrop was significantly high (26.8 +/- 4.8 and 13.4 +/- 2.7 mm P < .001); however, it was not laterally different (31. 5 +/- 5.1 and 31.7 +/- 5.0 mm). No acetabular components showed loosening. One metal shell was revised for wear and osteolysis. Morselized bone grafted in 25 hips was incorporated in all cases. Slight elevation of the hip center without lateralization in cementless cups fixed with screws was well tolerated for dysplastic hips.

Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ): a patient-based evaluation tool for hip-joint disease. The Subcommittee on Hip Disease Evaluation of the Clinical Outcome Committee of the Japanese Orthopaedic Association

BackgroundThe Japanese Orthopaedic Association Hip Score is widely used in Japan, but this tool is designed to reflect the viewpoint of health-care providers rather than that of patients. In gauging the effect of medical therapies in addition to clinical results, it is necessary to assess quality of life (QOL) from the viewpoint of patients. However, there is no tool evaluating QOL for Japanese patients with hip-joint disease.MethodsWith the aim of more accurately classifying QOL for Japanese patients with hip-joint disease, we prepared a questionnaire with 58 items for the survey derived from 464 opinions obtained from approximately 100 Japanese patients with hip-joint disease and previously devised evaluation criteria. In the survey, we collected information on 501 cases, and 402 were subjected to factor analysis. From this, we formulated three categories—movement, mental, and pain—each comprising 7 items, for a total of 21 items to be used as evaluation criteria for hip-joint function.ResultsThe Cronbach’s α coefficients for the three categories were 0.93, 0.93, and 0.95, respectively, indicating the high reliability of the evaluation criteria. The 21 items included some related to the Asian lifestyle, such as use of a Japanese-style toilet and rising from the floor, which are not included in other evaluation tools.ConclusionsThis self-administered questionnaire may become a useful tool in the evaluation of not only Japanese patients, but also of members of other ethnic groups who engage in deep flexion of the hip joint during daily activities.

Prevention of steroid-induced osteonecrosis by intravenous administration of vitamin E in a rabbit model

BackgroundWe focused on vitamins with marked antioxidant potency to see whether their use might prevent the development of steroid-induced osteonecrosis.MethodsFifteen Japanese white rabbits weighing about 3.5 kg were injected once into the right gluteal muscle with methylpred-nisolone (MPSL) 40 mg/kg (S group). In addition, 10 other rabbits received consecutive daily intravenous injections of vitamin E 50 mg/kg, starting from the day of MPSL administration (E group). All animals were killed 2 weeks after MPSL administration, and femurs were extracted and stained with H&E. Blood levels of reduced glutathione (GSH) were also measured.ResultsIn the S group the osteonecrosis development rate was 93%, in contrast to 0% in the E group (P < 0.01). Also, GSH levels in the S group abruptly decreased from the first day after MPSL administration, whereas in the E group, the decline in GSH levels was significantly suppressed on days 1 and 3 after MPSL administration (P< 0.05).ConclusionsVitamin E administration significantly inhibited steroid-induced oxidative stress. The results of this study suggest that the administration of vitamin E may be a novel and simple method to prevent the development of steroid-induced osteonecrosis.

Osteonecrosis Development in a Novel Rat Model Characterized by a Single Application of Oxidative Stress

OBJECTIVE To investigate the relationship between transient oxidative stress and the development of osteonecrosis in a rat model. METHODS A total of 160 male Wistar rats (24 weeks old) were injected only once with the pro-oxidant DL-buthionine-(S,R)-sulfoximine (BSO) (500 mg/kg given intraperitoneally) and were killed 12 hours (group A), 1 day (group B), 3 days (group C), 4 days (group D), 5 days (group E), 7 days (group F), or 14 days (group G) after administration (n = 20 per group). Twenty untreated rats were used as a control group (group N). Femurs were examined histopathologically for the presence of osteonecrosis, and reduced glutathione (GSH) in liver tissue was measured as an index of oxidative stress. RESULTS GSH decreased rapidly after BSO administration. Significant decreases were noted in groups A and B as compared to group N (P < 0.0001 and P = 0.0007, respectively), confirming the development of transient extreme oxidative stress soon after BSO administration. The histopathologic study revealed osteonecrosis in 10% of the rats in group E, 35% of the rats in group F, and 40% of the rats in group G. CONCLUSION Transient extreme oxidative stress was confirmed to induce osteonecrosis in this model. Since preparation of this model is extremely simple and because rats are well suited to genetic studies, this model may be of use in elucidating the pathophysiology of femoral head osteonecrosis in future studies.

Wear Comparison Between Conventional and Highly Cross-Linked Polyethylene Against a Zirconia Head A Concise Follow-Up, at an Average 10 Years, of a Previous Report

We previously reported the results of wear comparison at a minimum of 5 years between highly cross-linked polyethylene (HXLPE) and conventional polyethylene (PE) against a zirconia femoral head. We now report the mean wear at 10 years for 52 patients (56 hips) of the original cohort of 61 patients (65 hips) who had undergone primary total hip arthroplasty at our hospital between November 1999 and August 2000. The mean steady-state linear wear rate of HXLPE was 0.045 mm/y, compared with 0.080 mm/y for conventional PE (P=.0003). The incidence of osteolysis was 25% in the conventional PE group compared with 0% in the HXLPE group. Our study demonstrated that the steady-state wear rate for HXLPE remains significantly lower than that for conventional PE against a zirconia femoral head at a mean of 10 years after implantation.

Wear comparison between a highly cross-linked polyethylene and conventional polyethylene against a zirconia femoral head: minimum 5-year follow-up.

Highly cross-linked polyethylene (HXLPE) was developed to reduce wear of articular bearing surface in total hip arthroplasty patients. Several studies have shown reduced wear of HXLPE compared with conventional polyethylene; however, these studies had used HXLPE in combination with a Co-Cr metal head. The purpose of this study was to compare the 5-year in vivo wear of HXLPE with that of conventional PE using a zirconia femoral head. Forty-five hips with a Trilogy HXLPE (Zimmer, Warsaw, Ind) were matched and compared with a control group of 20 conventional Trilogy PE hips. The 2-dimensional linear wear rate was significantly less in the HXLPE group between 1 and 5 years postoperation (P < .001). The results show that HXLPE reduces short-term polyethylene wear against not only a Co-Cr head but also a zirconia head.

Rotational Acetabular Osteotomy for Osteoarthritis with Acetabular Dysplasia: Conversion Rate to Total Hip Arthroplasty within Twenty Years and Osteoarthritis Progression After a Minimum of Twenty Years

BACKGROUND We investigated the rate of conversion to total hip arthroplasty by twenty years and radiographic findings at a minimum of twenty years after rotational acetabular osteotomy. METHODS Between June 1986 and August 1991, we performed 172 rotational acetabular osteotomies in 168 patients with acetabular dysplasia. Of those, ninety-three hips (ninety-one patients), including twenty-three hips with pre-osteoarthritis, twenty-nine with initial osteoarthritis, and forty-one with advanced osteoarthritis, had clinical and radiographic findings available. The mean age of the patients was 32.4 years (range, twelve to forty-nine years). The duration of follow-up was a mean of twenty-three years (range, twenty to twenty-seven years) for seventy-six hips, excluding hips that underwent conversion to total hip arthroplasty. RESULTS Conversion to total hip arthroplasty by twenty years after surgery was performed in one hip (4%) with pre-osteoarthritis, two hips (7%) with initial osteoarthritis, and fourteen hips (34%) with advanced osteoarthritis. The hips with advanced osteoarthritis had a significantly higher rate of conversion to total hip arthroplasty than hips in the other stages did (p = 0.0005). At the latest follow-up or at conversion to total hip arthroplasty, the disease stage had not progressed in seventeen hips (74%) with pre-osteoarthritis, nineteen (66%) with initial osteoarthritis, and twenty-six (63%) with advanced osteoarthritis. CONCLUSIONS The progression of osteoarthritis after rotational acetabular osteotomy was not detected for at least twenty years in most hips with either pre-osteoarthritis or initial osteoarthritis in this cohort. Rotational acetabular osteotomy may delay conversion to total hip arthroplasty in advanced osteoarthritis. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Cementless Anatomic Total Hip Femoral Component With Circumferential Porous Coating for Hips With Developmental Dysplasia: A Minimum Ten-Year Follow-Up Period

Anatomic femoral components are optimized for primary osteoarthritis, and few long-term results for their use are available for developmental dysplasia of the hip (DDH). We reviewed 135 uncemented total hip arthroplasties in which an anatomic femoral component was used in 106 patients with DDH, excluding femurs with neck-shaft angles of >160° and femurs with anteversion of >50°. The mean age of patients at surgery was 49.4 years (range, 33-66 years), and the mean duration of follow-up was 13.5 years (range, 10-18 years). No osteoporotic femurs were included in our study group. Despite 18 acetabular revisions, no femoral component was removed for any reason. No femoral loosening was seen at the final follow-up examination. An anatomic femoral component with circumferential porous coating can produce good clinical and radiologic findings in young patients with good bone quality who have DDH without excessive femoral deformity.

How far above the true anatomic position can the acetabular cup be placed in total hip arthroplasty

Introduction There is controversy about which is more suitable for determining correct socket position in patients with severe bone deficiency of the acetabular roof because of developmental dysplasia of the hip (DDH): the anatomic centre of hip rotation or a high centre. Method We evaluated the relationship, in 200 hips, between the centre of rotation and presence of the Trendelenburg sign to determine the upper limit of cup position from the standpoint of hip-abductor strength. Results Of the 200 hips, 20 (10%) showed a positive Trendelenburg sign. There were no statistically significant differences between parameters (the centre of rotation, femoral offset, abductor lever arm) regarding the presence of the Trendelenburg sign except for age at surgery. Patients with a positive Trendelenburg sign were significantly older (64.1 ± 9.4 years) than those with a negative Trendelenburg sign (58.8 ± 7.7 years) (P = 0.01). Conclusions Our findings indicate that a high centre of hip rotation of up to approximately 30 mm from the inter-teardrop line is a feasible option for patients with DDH from the standpoint of hip-abductor strength if stems are used that allow the restoration of femoral offset and the abductor lever arm.

Osteocytic cell necrosis is caused by a combination of glucocorticoid-induced Dickkopf-1 and hypoxia

Osteonecrosis is a major glucocorticoid-induced complication in the orthopedics field. Despite the extensive researches, mechanisms underlining the glucocorticoid-induced osteonecrosis are largely unknown. Here, we first provide the evidence that a combined treatment of cultured osteocytic cells with glucocorticoid and hypoxia caused necrotic cell death, which is assumed to occur in the acute bone injuries induced by glucocorticoids. We cultured MLO-Y4 murine osteocytic cells under hypoxia in the presence or absence of Dexamethasone (Dex) and examined the rates of apoptotic and necrotic cell death. Dex or hypoxia alone increased apoptotic cells, but not necrotic cells. The combination of Dex and hypoxia dramatically increased osteocytic cell death, notably necrotic cell death. The expression of Dickkopf-1 (Dkk-1), an inhibitor of Wnt/β-catenin signal, was scarcely expressed in the control and hypoxic cells, but a dramatic increase of the Dkk-1 expression was detected in Dex-treated cells. siRNA-mediated knockdown of Dkk-1 in Dex and hypoxia-treated osteocytic cells showed the significant decreases in both apoptotic and necrotic cells. The results indicated that the combination of Dkk-1 overexpression by Dex and hypoxia causes the necrotic osteocytic cell death. The results also indicated that blocking of Dkk-1 can protect bone cells from glucocorticoid and hypoxia-induced cell injury.