Yukiharu Hasegawa

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.

Functional outcome after hip fracture in Japan

One thousand one hundred sixty-nine elderly Japanese patients who sustained a hip fracture were observed prospectively. Ninety-two percent had operative fracture treatment. Hospital length of stay averaged 67 days; 81% of patients were discharged to their place of residence where they resided before sustaining the fracture. Mortality rates at 120 days, 1 year, and 2 years after injury were 6%, 11%, and 19%, respectively. At 1-year followup, ambulatory status was recovered to that of the level experienced before injury in 67% of patients.

The natural course of osteoarthritis of the hip due to subluxation or acetabular dysplasia.

SummaryIn 59 patients, 86 hips with subluxation or hip dysplasia were examined to determine the natural course of the condition and select suitable treatment. Thirty-three percent of the joints (13/39 hips) developed early osteoarthritis from pre-osteoarthritis within an average term of 9.2 years, while the remaining, sixty-six percent (31/47 hips) developed advanced-stage osteoarthritis from early osteoarthritis within an average term of 7.8 years. Patients were classified into advanced and non-advanced groups according to radiographic analysis of the advance of the disease and statistical analysis was performed. In pre-osteoarthritis, centre-edge angle, slope of the acetabular roof, acetabular head index, acetabular depth ratio and Japanese Orthopaedic Association (JOA) hip score were significant predictors, while in early osteoarthritis, a broken Shentons line, cranial joint space and JOA score were significant. On the basis of multiple parameters, formulas for predicting development in patients with pre-osteoarthritis, those with early osteoarthritis, and all patients together were established, with an accuracy of 87%, 71%, and 68%, respectively.

Expression and enzymatic activity of MMP-2 during healing process of the acute supraspinatus tendon tear in rabbits.

We investigated the spontaneous healing process of a surgically created supraspinatus tendon tear in rabbits with specific reference to the expression of matrix metalloproteinase‐2 (MMP‐2) and its time‐course change in enzymatic activity along with the expression of tissue inhibitors of metalloproteinases (TIMPs). A transverse, full thickness tear of the supraspinatus tendon was created and examined. Immunohistochemical analysis revealed that MMP‐2 positive cells were mainly localized at both cutting ends of the tendon, and reparative tissue encroached into the gap from the bursal side. The expression of TIMP‐1 was induced in the cells at not only the tendon edges but also the reparative tissue during the healing process. TIMP‐2 was constitutively expressed in both the tendon and the reparative tissue. Gelatin zymography using tissue culture media demonstrated latent and active forms of MMP‐2 and characteristic time‐linked changes of the enzymatic activity. Western blotting confirmed the bands as the latent form of MMP‐2. These results suggest that MMP‐2 is expressed and activated during the healing process of acute supraspinatus tendon tear and can play an important role in the remodeling process.

Eccentric rotational acetabular osteotomy for acetabular dysplasia follow-up of one hundred and thirty-two hips for five to ten years

Background: Eccentric rotational acetabular osteotomy for the operative treatment of acetabular dysplasia consists of a spherical but eccentric osteotomy and rotation of the acetabulum that moves the center of rotation of the head of the femur medially and distally. No bone graft is needed. The reorientation of the acetabular fragment not only improves acetabular coverage but also restores the center of rotation of the subluxated hip. The purpose of this paper was to describe eccentric rotational acetabular osteotomy for the treatment of acetabular dysplasia and to evaluate its clinical and radiographic outcomes.Methods: We performed this procedure consecutively in 132 hips in 126 patients with dysplasia of the hip. Eighteen hips had no osteoarthritis, fifty-three had early osteoarthritis, and sixty-one had advanced osteoarthritis. Seven patients were male, and 119 were female. The average age was 36.5 years at the time of the index operation, and the average duration of follow-up was 7.5 years. Twenty-three hips in twenty-two patients were also treated with intertrochanteric valgus osteotomy to further improve joint congruency at the time of the acetabular osteotomy.Results: The average preoperative Harris hip score of 71 points improved to an average score of 89 points at the time of the latest follow-up. The average center-edge angle improved from 0° to 36°. An apparent change in the stage of the arthritis was observed in seven hips (5%), one of which had had early-stage disease and six of which had had advanced disease preoperatively.Conclusions: Eccentric rotational acetabular osteotomy appears to be a good treatment option for young patients with either early or advanced hip osteoarthritis secondary to dysplasia.

A computer simulation study of normal and abnormal hip joint contact pressure

The contact pressure on 112 normal hip joints and 66 acetabular dysplastic hip joints was analysed using a three-dimensional rigid body spring model. Geometric models were made from conventional anteroposterior radiographs, with the assumption that the acetabular surface was spherical. In normal hips, the distribution of contact pressure was almost even over the joint surface, and the maximum contact pressure was relatively low. However, in a dysplastic hip joint, the pressure was concentrated on the anterolateral edge of the acetabulum and increased enormously not only with the reduction in lateral coverage but also with the reduction in the anterior coverage of the acetabulum. This result indicates that a three-dimensional analysis is indispensable for estimating the mechanical effect on acetabular cartilage.

Indications and results of vascularized pedicle iliac bone graft in avascular necrosis of the femoral head

Several reports describe methods of treatment for avascular necrosis of the femoral head (ANFH) involving 0 to 2 mm of collapse. Some cases of ANFH have good prognoses, requiring only non-weight-bearing treatment. Other cases rapidly progress to collapse and complete destruction with enlargement of the necrotic area. The progression of the necrotic area is related to the activity of the original disease, steroid treatment, and the size and location of the necrotic area in the early stages of the disorder. In this report, a vascularized pedicle bone graft was used to treat ANFH, particularly those cases identified as Stage II on the system established by the Japanese Investigation Committee. Surgery involved curettage of necrotic bone, implantation of spongy bone, and application of a vascularized pedicle bone graft. Grafts were taken from the ilium and included the superficial circumflex iliac artery (SCIA). A bony canal was made in the anterior femoral neck, from which the necrotic bone was curetted and to which the bone graft was applied. The deep circumflex iliac artery (DCIA) was also used in combination with the SCIA. The postoperative weight-bearing period was six months. Follow-up periods lasted one to six years. Seventeen of 23 Stage II joints (19 cases) achieved satisfactory results at a mean of three years after surgery. Three Stage II joints and three Stage III joints continue to have significant problems. One of these six has been converted to a dual-bearing type endoprosthesis. The unsuccessful results generally occurred in patients who were treated with steroids.

Osteonecrosis of the femoral head after allogeneic bone marrow transplantation.

A comparative retrospective analysis of 100 consecutive patients after bone marrow transplantation was performed with magnetic resonance imaging in addition to plain radiography for the development of osteonecrosis of the femoral head. The incidence and risk factors for osteonecrosis of the femoral head were identified, comparing various parameters concerning bone marrow transplantation between the groups with and without evidence of osteonecrosis. Nineteen (19%) of 100 patients had osteonecrosis of the femoral head develop. Four factors were found to be statistically significantly different between patients who had osteonecrosis develop and those who did not: younger age at the time of bone marrow transplantation, chronic graft-versus-host disease, cumulative dose of steroid, and intravenous pulse therapy with methylprednisolone. It was concluded that a low rate of complications and low dose steroid administration would reduce the incidence of osteonecrosis after bone marrow transplantation.

Twenty years' followup of intertrochanteric osteotomy for treatment of the dysplastic hip

A followup study of more than 15 years of intertrochanteric osteotomy for osteoarthrosis of the dysplastic hip was performed in 52 hips of 42 patients with varus osteotomy and in 58 hips of 53 patients with valgus osteotomy. Varus osteotomy was indicated for predegenerative or early degenerative stages of osteoarthrosis, and valgus osteotomy was indicated for progressive or end stage disease. The average age at time of varus and valgus osteotomies was 25 and 37 years, respectively, and the average followup period was 21 and 20 years, respectively. Using Kaplan-Meiers method (end point, Harris Hip Score < 70 points or salvage operation), the 10- and 15-year survival rates for varus osteotomy were 89% and 87% and for valgus osteotomy were 66% and 38%, respectively. Radiographic measurements of the postoperative acetabular head index and center edge angle in varus osteotomy were better in the group with good results than those in the group with poor results. There were no differences in radiographic measurements between the group with good results and the group with poor results of valgus osteotomy. Intertrochanteric varus and valgus osteotomy delayed the need for total hip arthroplasty in young patients with osteoarthrosis of the dysplastic hip.

Curved intertrochanteric varus osteotomy for osteonecrosis of the femoral head

We reviewed the outcome of curved intertrochanteric varus osteotomy in the treatment of osteonecrosis of the femoral head in 20 hips. A mean varus angulation of 31 degrees was obtained by the osteotomy. The ratio of intact area on the weight-bearing portion increased from 19% to 61%. The mean elevation and lateral displacement of the greater trochanter were 1.2 cm and 0.5 cm, respectively. These changes in the position of the greater trochanter were very small when compared with those after conventional varus wedge osteotomy. Nonunion or delayed union was not observed. Quantitative analyses showed aggressive bone remodelling in the medial intertrochanteric region. Eighteen hips survived without collapse after a mean follow-up of 48 months. We conclude that curved varus osteotomy can be used to preserve the hip joint in patients with osteonecrosis of the femoral head.