Ayumi Kaneuji

A new cementless total hip arthroplasty with bioactive titanium porous-coating by alkaline and heat treatment: Average 4.8-year results

A method has been developed for creating a bioactive coating on titanium by alkaline and heat treatment, and shown that it forms a thin layer of hydroxyapatite (HA) on the surface of implants when soaked in simulated body fluid. A series of 70 cementless primary total hip arthroplasties using this coating technique on a porous titanium surface was performed, and followed up the patients for a mean period of 4.8 years. There were no instances of loosening or revision, or formation of a reactive line on the porous coating. Although radiography just after operation showed a gap between the host bone and the socket in over 70% of cases, all the gaps disappeared within a year, indicating the good osteoconduction provided by the coating. Alkaline-heat treatment of titanium to provide a thin HA coating has several advantages over plasma-spraying, including no degeneration or absorption of the HA coating, simplicity of the manufacturing process, and cost effectiveness. In addition, this method allows homogeneous deposition of bone-like apatite within a porous implant. Although this was a relatively short-term study, treatment that creates a bioactive surface on titanium and titanium alloy implants has considerable promise for clinical application.

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

OBJECTIVEnTo investigate the relationship between transient oxidative stress and the development of osteonecrosis in a rat model.nnnMETHODSnA 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.nnnRESULTSnGSH 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.nnnCONCLUSIONnTransient 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.

Stage-specific sagittal spinopelvic alignment changes in osteoarthritis of the hip secondary to developmental hip dysplasia.

Study Design. A retrospective, age- and sex-matched radiographic study. Objective. To compare the sagittal spinopelvic alignment in patients with hip osteoarthritis (OA) stratified by stage with that of age-matched control groups. Summary of Background Data. OA of the hip resulting from developmental hip dysplasia could be a cause of low back syndrome. OA of the hip may induce changes in sagittal alignment compared with healthy subjects. Methods. We studied 53 patients with OA of the hip secondary to developmental hip dysplasia, including 27 at the prearthritic/early stage (age, 34.0 years) and 26 at the advanced/terminal stage (age, 56.3 years). Comparisons were made with healthy females age-matched to each patient group (n = 13 and n = 15, respectively). Lateral roentgenograms of the lumbar spine and the hip joint were obtained in the upright position to determine pelvic inclination, sacral slope angle, lumbar lordotic angle (L1–L5), disc angle of L5/S1, and pelvic angle (by Jackson’s method). Results. Patients with pre/early-stage OA tended to have greater anterior pelvic inclination than healthy volunteers, although the difference was not significant. No significant differences were noted for other measurements. Lumbar lordotic and sacral slope angles were significantly greater in patients with advanced/terminal-stage OA than the control. Although lumbar lordotic and sacral slope angles decreased with aging in the healthy subjects, patients with OA retained the lumbar lordotic and sacral slope angles despite progression of OA with age. Conclusion. Pelvic inclination tended to increase in pre/early-stage OA patients. In healthy subjects, aging is associated with reduction of lumbar lordotic angle and tendency for posterior inclination of the sacrum. With aging, patients with OA maintained the lumbar lordotic angle and did not develop a posterior sacral slope angle.

Is the Bone-bonding Ability of a Cementless Total Hip Prosthesis Enhanced by Alkaline and Heat Treatments?

BackgroundCementless total hip arthroplasty (THA) implants using alkaline and heat treatments were developed to enhance bone bonding. Although bone-bonding ability of the alkali- and heat-treated titanium surface has been demonstrated in animal studies, it remains unknown whether it enhances or provides durable bone bonding in humans.Questions/purposesWe therefore (1) determined long-term survivorship, function, and radiographic signs of failure of fixation of alkali- and heat-treated THA implants; and (2) histologically examined their bone-bonding ability in two human retrievals.MethodsWe retrospectively reviewed 58 patients who underwent 70 primary THAs, of whom 67 were available for minimum followup of 8xa0years (average, 10xa0years; range, 8–12xa0years). Survival rate was calculated. Hip function was evaluated using the Japan Orthopaedic Association (JOA) hip scores, and radiographic signs of implant failure were determined from anteroposterior radiographs. Two retrieved implants were investigated histologically.ResultsUsing revision for any reason as the end point, the overall survival rate was 98% (95% confidence interval, 96%–100%) at 10xa0years. The patients’ average JOA hip scores improved from 47 points preoperatively to 91 points at the time of the last followup. No implant had radiographic signs of loosening. Histologically we observed bone in the pores 2xa0weeks after implantation in one specimen and apparently direct bonding between bone and the titanium surface in its deep pores 8xa0years after implantation.ConclusionsCementless THA implants with alkaline and heat treatments showed a high survival rate. Further study is required to determine whether the treatment enhances direct bone bonding.Level of EvidenceLevel IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

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

BACKGROUNDnWe 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.nnnMETHODSnBetween 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.nnnRESULTSnConversion 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.nnnCONCLUSIONSnThe 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.nnnLEVEL OF EVIDENCEnTherapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.