Motoki Sonohata

Silver oxide-containing hydroxyapatite coating has in vivo antibacterial activity in the rat tibia

Bacterial infection is a serious postoperative complication of joint replacement. To prevent infections related to implantation, we have developed a novel antibacterial coating with Ag‐containing hydroxyapatite (Ag‐HA). In the present study, we examined the antibacterial activity of Ag‐HA implant coatings in the medullary cavity of rat tibiae. Forty 10‐week‐old rats received implantation of Ag‐HA‐ or HA‐coated titanium rods, then were inoculated with ∼1.0u2009×u2009102 colony‐forming units of methicillin‐resistant Staphylococcus aureus. Bacterial counts were calculated for rats euthanized at 24, 48, and 72u2009h postoperatively. Serum levels of Ag (in the Ag‐HA group only) were calculated for rats euthanized at 24, 48, 72u2009h and 4 weeks. Radiographic evaluations of bone infection were also performed at 4 weeks. Tibiae from both groups showing infection were evaluated histologically. Significant differences in bacterial counts were seen at 24, 48, and 72u2009h. Mean concentrations of Ag in serum peaked about 48u2009h after implantation, then gradually decreased. Mean radiographic scores for infection were significantly lower with Ag‐HA implants than with HA implants. Histological examination showed better results for abscesses, bone resorption, and destruction of cortical bone around Ag‐HA‐coated implants. These results indicate that Ag‐HA coatings may help prevent surgical‐site infections associated with joint replacement.

Serum concentrations of interleukin-6 in patients following unilateral versus bilateral total knee arthroplasty

BackgroundSurgical stress is known to affect body temperature, white blood cell (WBC) count, C-reactive protein (CRP), and interleukin-6 (IL-6). The aim of the present study was to investigate which parameter is most suitable for quantitative analysis of surgical stress.MethodsUnilateral total knee arthroplasty (U-TKA) and bilateral TKA (B-TKA) were selected for the subjects of this study because the B-TKA creates approximately double the surgical stress of the U-TKA. The temperature, WBC count, CRP, and IL-6 in the blood were measured pre- and postoperatively in both groups. The IL-6 in the drainage fluid was also measured after the operation.ResultsThe temperature, WBC count, CRP, and IL-6 in the blood significantly increased on the first day after the operation in both groups. There were significant differences between the two groups in the WBC count (P < 0.05) and the IL-6 level in the blood (P < 0.05) on the first day after the surgery. There were no significant differences between the two groups for the CRP and IL-6 levels in the drainage fluid. The relative proportions — (B-TKA/U-TKA) × 100 (%) — were 170.4% for the operating time, 219.4 % for total blood loss, 200.0% for blood transfusion, 100.3% for temperature, 128.9% for WBC count, 127.4% for CRP, and 246.5% for the IL-6 level in the blood.ConclusionsThe serum IL-6 level may best reflect surgical stress and could therefore be a quantitative marker of surgical stress.

Comparison between topical and intravenous administration of tranexamic acid in primary total hip arthroplasty

BACKGROUNDnTranexamic acid has been reported to be safer with topical administration than with intravenous administration in total knee arthroplasty. However, the most effective administration route of tranexamic acid in total hip arthroplasty remains controversial. This study compared the effectiveness of topical tranexamic acid administration with that of intravenous tranexamic acid administration in total hip arthroplasty.nnnMETHODSnWe retrospectively examined the medical records of 886 patients with osteoarthritis of the hip joint, who had undergone unilateral primary total hip arthroplasty. The patients were divided into a control group (nxa0=xa0302; did not receive tranexamic acid), topical group (nxa0=xa0265; topically administered 2xa0g tranexamic acid in 30xa0mL normal saline via drain tubes placed in the joint before wound closure along with posterior soft tissue repair), and intravenous group (nxa0=xa0319; intravenously administered 1xa0g tranexamic acid before skin incision along with posterior soft tissue repair). Data on blood loss, hemoglobin levels, transfusion rates, and occurrence of deep vein thrombosis and pulmonary embolization were collected.nnnRESULTSnThe mean operation times were approximately 40xa0min in all of the groups. The operation time and intra-operative blood loss were significantly lower in the control group than in the topical and intravenous groups. However, the post-operative blood loss, total blood loss, and decrease in the hemoglobin level were significantly higher in the control group than in the topical and intravenous groups. There were no significant differences in terms of blood loss and systemic complications between the tranexamic acid administration methods.nnnCONCLUSIONSnTranexamic acid reduces both post-operative and total blood loss in total hip arthroplasty. Moreover, a lower amount of tranexamic acid can be used to reduce blood loss in total hip arthroplasty with intravenous tranexamic acid administration than with topical tranexamic acid administration. Therefore, we suggest that tranexamic acid should be intravenously administered pre-operatively and the posterior soft tissue should be repaired to decrease total hip arthroplasty-related complications.

First Clinical Experience With Thermal-Sprayed Silver Oxide–Containing Hydroxyapatite Coating Implant

BACKGROUNDnProsthetic joint infection is a serious complication of implant therapy. To prevent prosthetic joint infection, we previously reported the features of silver oxide-containing hydroxyapatite (Ag-HA), which was prepared by mixing silver (a metal with antimicrobial activity) with HA. In this study, we evaluated the potential issues of total hip arthroplasty (THA) with an Ag-HA-coated implant.nnnMETHODSnWe prepared an implant for THA that was coated with Ag-HA. In this study, the implant contained silver at a maximum quantity of 2.9 mg/implant. In this prospective interventional study, we performed THA with this implant in 20 patients and investigated the effects of silver.nnnRESULTSnBlood silver levels peaked at 2 weeks after THA and gradually decreased thereafter. The highest blood silver level recorded during the postoperative follow-up was 6.0 ng/mL, which was within the normal range. The Harris Hip Scores increased in all cases, and activities of daily living improved markedly after THA with Ag-HA-coated implants. Implant failure was absent on radiography. No adverse reaction to silver was noted, and argyria was not observed in any case. No patients have developed infection after surgery.nnnCONCLUSIONnThis is the first clinical study of Ag-HA-coated implants in THA. Our Ag-HA-coated implants markedly improved patients activities of daily living without causing any adverse reactions attributable to silver in the human body. Ag-HA is expected to reduce postoperative infections and prevent decreased quality of life in patients undergoing prosthetic arthroplasty, thus leading to more favorable outcomes.

Failure analysis of alumina on alumina total hip arthroplasty with a layered acetabular component: minimum ten-year follow-up study.

This prospective study reports the outcome of total hip arthroplasty (THA) performed in a consecutive series of patients using an alumina ceramic on a ceramic-layered component (Alumina-Bearing-Surface system). The cohort consisted of 270 hips in 229 patients. The study evaluated the clinical and radiological results over a mean follow-up of 11.4 years. Revision THA was performed on 58 hips, including alumina alternative failure in 50 hips, loosening in 4 hips, recurrent dislocation in 2 hips, stem neck fracture in 1 hip and hematoma in 1 hip. The survival rate was 68% with revision for any reason as the end point. The risk factors of implant failure are the preoperative range of motion of the hip joint and postoperative dislocation.

Shape of the joint gap for 90° and 120° knee flexion after total knee arthroplasty

BackgroundThe joint gap is set rectangular at 90° flexion during total knee arthroplasty (TKA). However, the condition of the joint gap in deep knee flexion is obscure.MethodsThe method for obtaining a posteroanterior view radiograph of the knee at 90° flexion (the epicondylar view) was modified, and a method to obtain an anteroposterior view radiograph at 120° flexion (deep flexion view) was established. With this method, subjects lie on the radiography table with their thighs placed on a device so their lower legs hang down in neutral rotation with a 1.5-kg weight attached to the ankle. The joint gap angle and medial and lateral joint space widths were measured on epicondylar view and deep flexion view radiographs in 20 normal male subjects, 20 normal female subjects, and 20 subjects after TKA.ResultsThe joint gap was almost rectangular at two flexion angles in normal subjects. In the implanted knees, the gap angle was 1.4° varus ± 3.3° (mean ± standard deviation), and no significant difference was found between medial and lateral joint space widths at 90° flexion. In contrast, the gap angle was 2.5° varus ± 2.5° and the lateral joint space width was significantly wider than the medial joint space width at 120° flexion (P < 0.001). The gap angle was more varus with a significant difference in the implanted knees than that in the normal subjects at 120° flexion (P < 0.001).ConclusionsThe joint gap was trapezoidal with a wider lateral side at 120° flexion even though it was almost rectangular at 90° flexion after TKA.

Total hip arthroplasty combined with double-chevron subtrochanteric osteotomy

BackgroundSubtrochanteric femoral shortening and corrective osteotomy are regarded as an integral part of total hip arthroplasty for a completely dislocated hip or severe deformity of the proximal femur. Alternative femoral osteotomy techniques—transverse, oblique, step-cut, and V-shaped, have been described.MethodsIn this series, we performed 22 cementless total hip arthroplasties combined with double-chevron subtrochanteric osteotomies between 1997 and 2002. There were 17 females and 2 males. Their average age at the time of the operation was 59xa0years (range 41–74xa0years). Thirteen hips were completely dislocated, 8 hips needed treatment after a proximal femoral osteotomy, and there was 1 case of hip ankylosis.ResultsThe mean length of the operation was 128xa0min (range 80–215xa0min). Mean total blood loss was 1442xa0g (range 809–2007xa0g), which included both the intraoperative blood loss and postoperative blood loss. After an average of 7.6xa0years of follow-up, the Japanese Orthopaedic Association Hip Score improved from 48 to 79. Three types of complication were observed. There were 4 early dislocations, 3 proximal splits, and 1 nonunion at the osteotomy site.ConclusionsOur study shows that acceptable results are obtained from double-chevron subtrochanteric osteotomy for subtrochanteric femoral shortening and corrective osteotomy. However, total hip arthroplasty combined with subtrochanteric osteotomy is a technically demanding treatment option.

Supratentorial subdural hemorrhage of a previous head injury and cerebellar hemorrhage after cervical spinal surgery: a case report and review of the literature.

Study Design. Case report. Objective. To report a case of an acute supratentorial subdural hemorrhage (SDH) of a previous head injury site and cerebellar hemorrhage, after an incidental dural tear during spine surgery. Summary of Background Data. Intracranial hemorrhage, such as subdural, cerebellar, subarachnoid, and epidural hemorrhage after a dural tear during spinal surgery, is a rare and poorly recognized complication. Moreover, only 3 cases in patients with concurrent SDH and cerebellar hemorrhage have been described in the literature, and none of these reports demonstrated the bleeding point on the adhesion site of the dural at the regions of the previous head injury. Methods. A case report and literature review are presented. Results. A 46-year-old male underwent occipital cervical surgery for os odontoideum. Intraoperatively, a dural tear was noted and repaired, but he later developed postoperative disturbance of consciousness. A head computed tomographic scan revealed a supratentorial SDH and cerebellar hemorrhage. Evacuation of the supratentorial SDH was performed via craniotomy, and the bleeding point was revealed to be on the adhesion site of the dural where the patient had experienced a previous head injury. The patient made a full recovery. Conclusion. This report illustrates that cerebrospinal fluid leakage after a dural tear during spinal surgery may cause intracranial hemorrhage. A previous head trauma could be a risk factor for such hemorrhagic complications. Headache, nausea, and postoperative stupor after spinal surgery, especially after an accidental durotomy, should be considered possible indications of intracranial hemorrhage, and affected patients should be investigated with computed tomography or magnetic resonance imaging. Level of Evidence: N/A

The termination level of the conus medullaris and lumbosacral transitional vertebrae

BackgroundThe presence of lumbosacral transitional vertebrae (LSTV) may affect the variation of the termination level of conus medullaris (TLCM). However, there have been few studies examining the association between the distribution of the TLCM and LSTV, especially in young patients. The purpose of this investigation was therefore to assess the relationship between the TLCM and LSTV in young patients.MethodsA total of 379 patients with lumbar herniated disks were included in this study. There were 249 males and 130 females, with a mean age of 31xa0years (range 15–44). The patients were classified into three groups: (1) L4/TV group (7xa0%): 28 patients with sacralization of the fifth lumbar vertebrae; (2) L5/TV group (11xa0%): 41 patients with lumbarization of the sacrum; and, (3) normal group (82xa0%): 310 patients without LSTV. TLCM was assessed using MRI.ResultsThe median TLCM of the normal, L4/TV and L5/TV groups was the middle third of L1, the upper third of L1 and the lower third of L1, respectively. The TLCM in the L4/TV group was significantly higher than that observed in the normal group (pxa0<xa00.001), while that in the L5/TV group was significantly lower than observed in the normal group (pxa0<xa00.001).ConclusionsThe presence of LSTV affected the variation of the TLCM. Therefore, the distribution of the TLCM with or without lumbosacral TV may help clinicians to identify the neurological discrepancies observed among neurologic injuries at the thoracolumbar junction.

Neonate with calcinosis cutis following extravasation of calcium gluconate

Calcium gluconate has been widely used in the management of neonatal hypocalcemia. When extravasation of a calcium gluconate infusion occurs, there may be rapid and marked swelling, erythema, and signs of soft tissue necrosis or infection, with ensuing extensive local calcifi cation, called calcinosis cutis. In most cases, calcinosis cutis following extravasation of calcium gluconate can be treated conservatively without any special treatment. However, it is often diffi cult to make a proper diagnosis because the disease is rare in the orthopedic fi eld, there is a time discrepancy between the clinical symptoms and radiographic fi ndings, and most patients are neonates. There are only two reports of this disease in the orthopedic literature. This report describes a neonate with “calcinosis cutis” following extravasation of calcium gluconate. The patient’s family was informed that the data from this case would be submitted for publication, and they gave their consent.