Takehiko Torisu

Proinflammatory cytokine (TNFalpha/IL-1alpha) induction of human osteoclast formation.

TNFα and IL‐1α are potent stimulators of bone resorption in vivo and in vitro. Recently, it has been demonstrated that these two cytokines directly induce osteoclastogenesis in mouse marrow cultures. This study determined whether TNFα (± IL‐1α) is also capable of inducing human osteoclastogenesis. The CD14+ monocyte fraction of human peripheral mononuclear cells was cultured with TNFα ± IL‐1α in the presence of M‐CSF. TNFα induced the formation of multinucleated cells (MNCs) which were positive for TRAP, VNR and cathepsin K and showed evidence of resorption pit formation. IL‐1α stimulated TNFα‐induced lacunar resorption two‐ to four‐fold. Osteoprotegerin, the decoy receptor for RANKL, did not inhibit this process. Anti‐human IL‐1α neutralizing antibodies significantly inhibited resorption without inhibiting the formation of TRAP+/VNR+ MNCs. These results suggest that, in the presence of M‐CSF, TNFα is sufficient for inducing human osteoclast differentiation from circulating precursors by a process which is distinct from the RANK/RANKL signalling pathway. Copyright

Mortality after hip fracture in Japan: the role of nutritional status.

Purpose. To assess factors that influence 4-year mortality following hip fracture surgery in a Japanese population. Methods. Records of 129 hips in 24 men and 103 women aged 50 to 103 (mean, 79) years who underwent surgery for femoral neck or trochanteric fractures were reviewed. Clinical data reviewed included age, gender, body mass index (BMI), side of fracture, fracture type, fracture stability, surgery type, interval from admission to surgery, length of hospital stay, number of pre-fracture comorbidities, pre-fracture ambulatory level, pre-fracture place of residence, preoperative dementia, preoperative skeletal traction, blood haemoglobin level, serum albumin level, number of postoperative complications, and postoperative delirium. Univariate and multiple logistic regression analyses were performed to identify the relative contribution of the variables to mortality. Receiver operating characteristic (ROC) curves were used to identify optimal cut-off levels. Results. The 4-year mortality was 48%. Multiple logistic regression analysis showed that serum albumin level (p=0.0004, odds ratio [OR]=5.8541) and BMI (p=0.0192, OR=1.1693) significantly influenced mortality; the cut-off points were 36 g/l and 18.9 kg/m2, respectively, based on the ROC curves. Kaplan-Meier curves showed that survival rates were significantly worse in patients with values below these cut-off points. Conclusion. Serum albumin level and BMI on admission are predictive of mortality after hip fracture surgery.

Synovectomy, debridement, and continuous irrigation for infected total knee arthroplasty

Since 1990, a total of ten joints in nine patients with infected total knee arthroplasty have been treated in our department within 21 days of the onset of infection. Their radiographs showed no evidence of implant loosening or “moth-eaten” appearance. They underwent synovectomy, debridement, and continuous irrigation without implant removal. Continuous irrigation was maintained for 7–29 days. It was possible to retain implants in eight joints of seven patients. Two joints of two patients were removed. Pain disappeared in all eight joints in which the implants were retained. Four patients could walk with one cane; one patient could walk with one crutch. Range of motion in five joints remained over 100°. We recommend synovectomy, debridement, and continuous irrigation to cure an early stage infection of total knee arthroplasty.RésuméDepuis 1990, dix articulations chez neuf malades avec une arthroplastie totale infectée du genou ont été traité dans notre département dans les 21 jours après le début de l’infection. Les radiographies n’ont pas montré de descellement d’implants ou d’anomalie de la texture osseuse. Ils ont subi synovectomie, débridement et irrigation continue sans ablation de l’implant. L’irrigation continue a été maintenue pour sept à 29 jours. Il a été possible de conserver les implants de huit articulations chez sept malades. Deux articulations de deux malades ont subi l’ablation de l’implant. La douleur a disparu de toutes les articulations ou les implants avaient été conservés. Quatre malades devaient marcher avec une canne et un avec une béquille. L’amplitude de mobilité est restée au-dessus de 100° pour cinq articulations. Nous recommandons la synovectomie, le débridement et l’irrigation continue pour traiter une infection précoce d’arthroplastie totale du genou.

Contrast-enhanced MR imaging of subchondral insufficiency fracture of the femoral head: a preliminary comparison with that of osteonecrosis of the femoral head

IntroductionSubchondral insufficiency fracture of the femoral head (SIF) may be confused with osteonecrosis of the femoral head (ON) due to clinical and imaging similarities.Materials and methodsContrast-enhanced MR images in patients with SIF (ten hips in ten patients) were retrospectively reviewed and compared with those from patients with ON (ten hips in six patients).ResultsLow-signal intensity bands on T1-weighted images were present within the femoral head in all hips examined. The segment proximal to the band was contrast-enhanced following IV gadolinium administration in nine of ten hips (90%) with SIF and in none of the 10 hips with ON.ConclusionThese results suggest that the presence of contrast enhancement in the segment proximal to the low-signal intensity band in the femoral head may serve as a supplemental diagnostic measure for the differentiation of SIF from ON.

Bipolar hip arthroplasty without acetabular bone—grafting for dysplastic osteoarthritis: Results after 6–9 years

Abstract The authors report the clinical and radiographic results of 36 bipolar hip arthroplasties after performing excavation of the steep and shallow acetabulum without acetabular bone—grafting for dysplastic osteoarthritis. The procedures were carried out between 1981 and 1985. Survivorship analysis showed that 84.6 of the bipolar hip arthroplasties were retained for 8 years. Twenty-nine patients, which were followed for 6–9 years after surgery, were reviewed. Severity of acetabular dysplasia was classified according to the method of Crowe. Class 1 included 17 hips and class 2 included 12 hips. The average preoperative clinical score was 49 points. The average postoperative clinical hip score improved to 87 points after 6 years. Twenty-seven of the 29 hips assessed were classified as either excellent or good by Charnleys function score. Stress fracture, due to excessive acetabular excavation at the time of surgery, and femoral component loosening were major symptomatic complications. The cessation of radiographic evidence of migration of the bipolar socket was recognized in 25 of 29 procedures at 6 years after surgery (86.2%). Cineradiographic study demonstrated that the abduction motion under standing position for 20 of 24 hip joints functioned dominantly at the inner-bearing and metallic—stem interface.

Joint Motion of Bipolar Femoral Prostheses

From 1982 to 1992, 251 bipolar hip arthroplasties were performed on 213 patients. Among them, 117 bipolar femoral prostheses were randomly selected to examine the behavior of abduction motion under weight-bearing loads. Roentgenographic motion study was performed at an average of 46.5 months after surgery (range, 2-110 months). One hundred one prostheses used in dysplastic osteoarthritic, rheumatoid, and revised failed total hip arthroplasty patients moved 18.2% at the outer bearing and 81.8% at the inner bearing, while 16 prostheses used in femoral neck fracture and osteonecrosis of the femoral head patients moved 49.7% at the inner bearing and 50.3% at the outer bearing. There was a statistical difference in the motion pattern between the two groups. The abduction motion behavior of the bipolar femoral prostheses was not affected by the length of the follow-up period, the diameter of the outer heads, or the position of the prostheses on immediate postoperative roentgenograms.

Subchondral Insufficiency Fracture of the Femoral Head may be Associated with Hip Dysplasia: A Pilot Study

BackgroundSubchondral insufficiency fracture of the femoral head occurs mainly in elderly patients with osteoporosis. Spontaneous resolution is observed after nonoperative treatment in some patients whereas other show progressive joint destruction requiring THA. Several studies report the occurrence of subchondral insufficiency fracture of the femoral head in dysplastic hips.Questions/purposesWe asked whether the extent of hip dysplasia or osteoporosis was greater in patients with subchondral insufficiency fracture of the femoral head than in normal control subjects.Patients and MethodsWe compared the clinical and imaging findings of 13 patients with subchondral insufficiency fractures of the femoral head and 12 patients scheduled for TKA with asymptomatic hips. Age, gender, and body mass index were comparable in the two groups.ResultsHigher mean Sharp angles, lower acetabular head indices, lower center-edge angles, and higher acetabular roof angles in patients with subchondral insufficiency fracture of the femoral head than in those with asymptomatic hips suggested a greater degree of hip dysplasia. Bone mineral density and serum levels of Type I collagen cross-linked N-telopeptide and bone alkaline phosphatase were similar in the two groups.ConclusionsWe speculate an excessive amount of stress on the acetabular edge from dysplasia may be associated with the occurrence of subchondral insufficiency fracture of the femoral head.

Analysis of wear and oxidation on retrieved bipolar polyethylene liner

BackgroundFor bipolar prostheses, most of the previous studies attributed the occurrence of osteolysis to wear debris generated from the bearing surface. We looked closely into the wear debris and reported on our findings with respect to the oxidation index and the rate of wear in ultra-high molecular weight polyethylene (UHMWPE) inserts retrieved from bipolar prostheses after various spans of time in vivo.MethodThe inserts were retrieved from the heads of three types of bipolar prosthesis (UH1, UPF1, UPF2). We retrieved 24 bipolar prostheses from 23 patients whose mean implantation period was 10.0 years (2.7–15.4 years).ResultsAll the retrieved polyethylene had a burnished bearing surface. In all, 92% (22/24) of these inserts had indentation and roughness at the rim and flange, suggesting neck-cup impingement; periprosthetic fracture occurred in the other two inserts. The mean linear wear rate was 0.035 mm per year. The average maximum oxidation index for the inserts with osteolysis was 3.34, and it was was 3.49 for the inserts without osteolysis. We, therefore, could not detect any significant difference between the aforesaid groups of inserts.ConclusionsThe results strongly suggest that most of the polyethylene wear debris was not generated from the bearing surface. Moreover, the wear debris generated from neck-cup impingement may well be the cause of an inflammatory reaction, which in turn has a strong potential to become the primary cause of osteolysis.

Role of multinuclear cells in granulation tissue in osteomyelitis Immunohistochemistry in 66 patients

We investigated the origin of multinuclear cells (MNCs) in the granulation tissue in osteomyelitis by immunohistochemical techniques in 66 patients. 12 samples were analyzed for the presence of CD68, cathepsin K, CD11b and tartrate-resistant acid phosphatase (TRAP) activity. Many MNCs were present in the granulation tissue adjacent to a sequestrum. MNCs in contact with the sequestrum were also noted, however, no osteoblasts were found. Immunohistochemically, CD68, cathepsin K and TRAP were strongly expressed in most of the MNCs, while CD11b positive cells were not found. MNCs remote from and in contact with the sequestrum showed the same immunohistochemical features which are characteristic of osteoclasts. Further, MNCs in contact with the sequestrum had originally developed in the granulation tissue and directly infiltrated towards the sequestrum without cellto-cell interaction with osteoblasts.

Risk factors leading to total hip arthroplasty in patients with subchondral insufficiency fractures of the femoral head.

Purpose. To retrospectively evaluate factors leading to total hip arthroplasty (THA) in patients with subchondral insufficiency fractures (SIF) of the femoral head. Methods. 5 men and 22 women aged 51 to 85 (mean, 72) years with SIF of the femoral head initially underwent conservative treatment. THA was later performed for 13 patients, as the hip pain became worse secondary to joint space narrowing and/or femoral head collapse. Patient demographics and radiological variables were retrieved. Risk factors leading to THA in patients with SIF of the femoral head were identified. Receiver operating characteristic curves were used to determine optimal cut-off values for the significant risk factors. Results. 2 men and 11 women aged 62 to 85 (mean, 74.9) years underwent THA and were followed up for 0.2 to 62 (mean, 13) months. The remaining 3 men and 11 women aged 51 to 81 (mean, 68) years underwent conservative treatment and were followed up for 9 to 93 (mean, 28) months. Patient age was the only risk factor for THA (p=0.047, odds ratio=1.13), the cut-off value being 71 years (sensitivity, 77%; specificity, 64%). The survival rate was significantly lower in patients aged ≥71 years than in those aged <71 years (p<0.05). Conclusion. Elderly patients with SIF of the femoral head are at higher risk of undergoing THA.