Shinji Kitamura

Biological reaction to alumina, zirconia, titanium and polyethylene particles implanted onto murine calvaria.

Periprosthetic osteolysis is a serious problem that limits long-term survival of total hip arthroplasty. Ceramics have been introduced as a joint surface material to reduce osteolysis due to wear particles. The aim of this study is to investigate the biological reaction of ceramic particles on murine calvarial bone, in comparison with polyethylene and titanium particles. Sixty CL/BL6 mice were divided into five groups according to the materials implanted onto the murine calvariae: control, Al(2)O(3), ZrO(2), high-density polyethylene (HDP) and Ti6Al4V. One week after the implantation, each calvarial tissue was dissected and the release of proinflammatory mediators (IL-1beta, IL-6, TNF-alpha) and bone resorption were assessed. The particles of HDP and Ti6Al4V induced three and two times larger osteolytic lesions than the control, respectively. The levels of IL-1beta and IL-6 were significantly elevated in the medium subcultured with the calvariae of HDP and Ti6Al4V groups. Any particle type did not increase the levels of TNF-alpha. There were no significant differences observed in the levels of proinflammatory mediators or osteolytic area among Al(2)O(3), ZrO(2) and control groups. The inflammatory response and bone resorption induced by ceramic particles were much smaller than those induced by HDP and Ti6Al4V. These biological features suggest the biocompatibility of ceramics as a joint surface material for artificial joints.

Osteonecrosis of the femoral head associated with pregnancy

Abstract A 31-year-old pregnant woman suddenly complained of bilateral hip pain 2 weeks before delivery. She was delivered of triplets by Caesarean section. She had been treated with human menopausal gonadotropin and human chorionic gonadotropin (hMG-hCG) before pregnancy. Radiograms of the hip joint showed collapse of the femoral heads bilaterally. Magnetic resonance imaging revealed a band pattern of low signal intensity for both hips on T1- and T2-weighted images. She had no history of steroid therapy or alcohol abuse. Osteonecrosis of the femoral heads bilaterally associated with pregnancy was confirmed. Pathology of the femoral head showed typical empty lacunae and necrosis of the trabecula.

Transtrochanteric rotational osteotomy for osteonecrosis of the femoral head

We reviewed 48 hips in 43 patients 3–7.1 years (average 4.6 years) after Sugioka transtrochanteric rotational osteotomy for osteonecrosis of the femoral head. The average age at operation was 41 years. Thirty-four patients were men and 9 women. Overall results at the final follow-up were satisfactory in 30 hips (62%). Kaplan-Meiers survivorship was 62% at 3 years and 60% at 5 years postoperatively. Six hips for which the ratio of the intact area of the articular surface on the preoperative lateral radiograph was less than 30% showed further collapse. Five hips were converted to bipolar hemiarthroplasties or total hip arthroplasties. Complications, such as varus deformity, subtrochanteric fracture, and ectopic bone formation, occurred in eight hips. Five of them were operated on in the first 2 years of this series. Three of these five operations had unsatisfactory results. We conclude that satisfactory results can be achieved using this osteotomy by maintaining exact surgical technique and by limiting the surgical indications to hips with an intact area of more than one-third of the entire articular surface on the lateral radiograph of the femoral head.

Eccentric Rotational Acetabular Osteotomy for Acetabular Dysplasia and Osteoarthritis: Follow-up at a Mean Duration of Twenty Years

BACKGROUND The aim of the eccentric rotational acetabular osteotomy is to correct the deficient acetabular coverage in the dysplastic hip in order to limit the development of secondary osteoarthritis. The purpose of this study was to investigate the results in patients managed with an eccentric rotational acetabular osteotomy after a mean of twenty years. METHODS The clinical and radiographic outcomes for the first 126 consecutive patients (132 hips) who underwent an eccentric rotational acetabular osteotomy at our institution were retrospectively evaluated. One hundred and twenty-four patients (130 hips) were evaluated; 117 were women (123 hips). The mean patient age was thirty-seven years (range, fifteen to fifty-nine years) at the time of surgery, and the average duration of follow-up was twenty years. Twenty-three hips in twenty-two patients were also treated with intertrochanteric valgus osteotomy at the time of the eccentric rotational acetabular osteotomy to further improve joint congruency. RESULTS The mean preoperative Harris hip score of 70 points (range, 51 to 90 points) improved to a mean of 88 points (range, 35 to 100 points) at the final follow-up. Thirty hips had a fair clinical outcome (Harris hip score, <80 points). In seventeen hips, the eccentric rotational acetabular osteotomy was converted to a total hip arthroplasty. The cumulative survivorship at fifteen years and at the final follow-up at twenty-three years was 97% and 80%, respectively. Four factors led to a poor outcome: a small (≤2.0-mm) preoperative minimum joint space, joint incongruence, simultaneous intertrochanteric valgus osteotomy, and lateral subluxation of the femoral head postoperatively. CONCLUSIONS Eccentric rotational acetabular osteotomy is an effective surgical procedure for treating symptomatic dysplastic hips before, and in the early stages of, osteoarthritis. The majority of patients maintained excellent or good native hip function at a mean of twenty years after surgery. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Catastrophic Failure of Cementless Total Hip Arthroplasty Using a Femoral Component Without Surface Coating

Consecutive series of 90 hips that had had a primary cementless arthroplasty with use of straight collarless stems between January 1988 and September 1992 were reviewed. Twenty-eight hips with Omnifit Normalized Stems (Fit-N) and 45 hips with Omniflex Normalized Stems (Flex-N) without porous coatings were compared clinically and radiographically with 17 hips with Omnifit Microstructured Stems (Fit-M) with porous coating. The average follow-up periods for the 3 stems were 97 months, 73 months, and 93 months. Revision was performed or awaited in 9 cases (32.1%) in the Fit-N group, 18 cases (40.0%) in the Flex-N group, and 1 case (5.8%) in the Fit-M group. The average annual subsidence was 0.62 mm/y, 0.73 mm/y, and 0.17 mm/y. Osteolysis of more than 3 mm occurred in 28.6%, 37.8%, and 23.5%. Fit-N stems and Flex-N stems without porous coatings are not appropriate for cementless total hip arthroplasty.

Increased expression and activation of cathepsin K in human osteoarthritic cartilage and synovial tissues

Few studies have analyzed Cathepsin K (CatK) expression in human osteoarthritic tissues. We investigated CatK expression and activation in human articular cartilage using clinical specimens. Human osteoarthritic cartilage was obtained during surgery of total hip arthroplasty (n = 10), and control cartilage was from that of femoral head replacement for femoral neck fracture (n = 10). CatB, CatK, CatL, CatS, and Cystatin C (CysC) expressions were evaluated immunohistochemically and by real‐time PCR. Intracellular CatK protein was quantified by ELISA. Intracellular CatK activity was also investigated. Osteoarthritis (OA) chondrocytes were strongly stained with CatK, particularly in the superficial layer and more damaged areas. CatB, CatL, CatS, and CysC were weakly stained. CatK mRNA expression was significantly higher in OA group compared to that in control group (p = 0.043), whereas those of CatB, CatL, CatS, and CysC did not differ significantly. Mean CatK concentration (4.83 pmol/g protein) in OA chondrocytes was higher than that (3.91 pmol/g protein) in control chondrocytes (p = 0.001). CatK was enzymatically more activated in OA chondrocytes as compared with control chondrocytes. This study, for the first time, revealed increased CatK expression and activation in human OA cartilage, suggesting possible crucial roles for it in the pathogenesis of osteoarthritic change in articular cartilage.

Bone scintigraphy and magnetic resonance imaging after transtrochanteric rotational osteotomy.

Abstract Objective. To assess the ability of bone scintigraphy and magnetic resonance imaging (MRI) to predict the outcome of transtrochanteric rotational osteotomy (TRO) for osteonecrosis of the femoral head (ONFH). Design. This study was a prospective evaluation of imaging techniques. Patients and methods. MRI and bone scintigraphy were performed on 20 hips in 18 patients at 3 months after TRO. The radiographic findings at 3 months after TRO, and the MRI and bone scintigraphic findings, were compared with the radiographic findings at final follow-up (mean 39 months). Results and conclusions. On MRI a low-intensity area or a low-intensity band in the new weight-bearing area extending over the acetabular edge on T1-weighted images was related to the presence of collapse on the radiographs at final follow-up. In hips with an area of absent activity in the new weight-bearing surface on bone scintigraphy, collapse was seen more frequently on radiographs at final follow-up than in hips without this feature. Bone scintigraphy was no more specific than radiography in predicting the outcome after TRO. We consider MRI to be superior to bone scintigraphy in predicting the occurrence of collapse, which is one of the major short-term problems after TRO.

Scintigraphic evaluation of transtrochanteric rotational osteotomy for osteonecrosis of the femoral head

Scintigrams and radiographs of 36 femoral heads in 34 patients before and after Sugiokas transtrochanteric rotational osteotomy for osteonecrosis of the femoral head were investigated prospectively. Patients were followed for more than 3 years after the operation. The patterns of early scintigrams made within 3 months of the operation were classified into four categories. All 4 patients with a large cold area evidenced collapse within I year despite good recovery of the weight-bearing surfaces immediately after operation on conventional radiograms. Twenty-two hips with no cold area in the femoral head did not demonstrate collapse. Femoral head collapse after rotational osteotomy can be predicted by early postoperative bone scintigraphy.

Effects of recombinant human erythropoietin on thrombosis and fibrinolysis in autologous transfusion for hip surgery.

Abstract Recombinant human erythropoietin (rHuEPO) is effective in allowing autologous blood donation in patients unable to donate because of anemia. As adverse effects of rHuEPO might include activation of coagulation and possibly fibrinolysis, we investigated these possibilities in the context of autologous blood donation preceding hip surgery. Thirty-seven patients who donated 800 ml of autologous blood for elective hip surgery were randomly assigned to either a group of 20 receiving preoperative treatment with rHuEPO (erythropoietin β), 6000 U i.v. twice weekly for 3 weeks, or an untreated control group of 17. A significant increase in platelet count was associated with autologous blood donation and intraoperative blood loss with or without rHuEPO. Coagulation and fibrinolysis were increased significantly by intraoperative blood loss in both groups, but not by rHuEPO. Coagulation and fibrinolysis were not activated by rHuEPO for elective hip surgery.

Characterization and Biological Application of Hydroxyapatite-Glass-Titanium (HA-G-Ti) Functional Gradient Composite Material

Osteolysis has emerged as a common cause of loosening in cementless total hip arthroplasty. For the purpose of resolving osteolysis, plasma-sprayed hydroxyapatite (HA)-coated Ti implants were developed. However, delamination of HA has often occurred. There is a serious problem of adhesive quality between the HA layer and the substrate, mainly caused by the large difference in the linear thermal expansion coefficient between the substrate and HA. Bioactive composites comprising HA containing glass (G)-coated titanium (Ti) or titanium alloy (Ti-6A1-4V), so-called HA-G-Ti functional gradient composite materials, providing both the bioactivity potential due to the HA and the mechanical strength of titanium or alloy, were subjected to experiments under in vitro and in vivo conditions. In the former, as a characterization of HA-G-Ti composites, the structural features and properties, chemical stability, and electrochemical corrosion and then the bioactivity, involving the precipitation of apatite under physiological conditions, are summarized. In the latter, the experiments of implantation of the HA-G-Ti composites into mandibular bone, femur, and tibia of dogs were performed. The bonding behavior at the interface between the implants and the surrounding bone tissue, as well as the bonding strength and histocompatibility, have been extensively investigated. It is concluded that the HA-G-Ti composite is an excellent biomaterial, applicable in prostheses such as cementless artificial joints (HAPG-Profile). Clinical trials of HAPG-Profile are now going on.