Tamon Kabata

Polyneuropathy caused by cobalt–chromium metallosis after total hip replacement

Although metal intoxication after arthroplasty causes various symptoms, polyneuropathy has never been the focus of clinical investigation. We report the case of a 56‐year‐old woman with metal neuropathy. She had metallosis after hip arthroplasty with a cobalt–chromium alloy prosthesis. She developed progressive sensory disturbance, hearing loss, and hypothyroidism. Sural nerve biopsy indicated axonopathy. After exchange arthroplasty, blood levels of cobalt and chromium decreased, and her symptoms improved. Cobalt or chromium can cause axonopathy. Muscle Nerve, 2010

Deformity correction followed by lengthening with the Ilizarov method.

Deformity combined with shortening of 18 lower limb segments of 17 patients was treated with the Ilizarov method. Limb lengthening was done at the same treatment (monofocal treatment) or a separate osteotomy (bifocal treatment) was done after acute or gradual correction of the deformity using the Ilizarov hinge system. The external fixation time, amount of deformity correction, length gained, and incidence of complications were examined. Results were compared between monofocal versus bifocal treatment groups and between femoral versus tibial procedures. The average deformity corrected was 22.3°, and the average lengthening was 44.4 mm. The external fixation index was 49.3 days/cm on average, ranging from 24.4 to 90 days/cm, and the mean duration of external fixation was 198 days, ranging from 77 to 352 days. Major complications requiring surgical treatment, such as premature consolidation and fracture, were seen in four patients. There were no statistically significant differences between the results for monofocal and bifocal treatment or treatment indices for femoral and tibial operations. The Ilizarov method was very effective for treatment of limb deformity combined with shortening. Monofocal treatment might be better if the total amounts of lengthening required are short to reduce surgical invasion. Longer treatment indices for tibial operations could not be verified from the current study.

Reconstruction with Distraction Osteogenesis for Juxta-articular Nonunions with Bone Loss

BACKGROUND Nonunions of a juxta-articular lesion with bone loss, which represent a challenging therapeutic problem, were treated using external fixation and distraction osteogenesis. METHODS Seven juxta-articular nonunions (five septic and two aseptic) were treated. The location of the nonunion was the distal femur in four patients, the proximal tibia in one patient, and the distal tibia in two patients. All of them were located within 5 cm from the affected joints. Preoperative limb shortening was present in six cases, averaging 2.9 cm (range, 1-7 cm). The reconstructive procedure consisted of refreshment of the nonunion site, deformity correction, stabilization by external fixation, and lengthening to eliminate leg length discrepancy or to fill the defect. Shortening-distraction was applied to six patients and bone transport to one patient for reconstruction. Intramedullary nailing to reduce the duration of external fixation was simultaneously performed in two cases. All the patients had at least 1 year of follow-up evaluation. RESULTS Osseous union without angular deformity or leg length discrepancy greater than 1 cm was achieved in all patients. The mean amount of lengthening was 5.8 cm (range, 2.2-10.0 cm). The mean external fixation period was 219 days (range, 98-317 days), and the mean external fixation index was 34.4 days/cm (range, 24.5-47.6 days/cm). All patients reported excellent pain reduction. There were no recurrences of infection in five patients with prior history of osteomyelitis. The functional results were categorized as excellent in two, good in three, and fair in two. CONCLUSION Despite the length of postoperative external fixation, distraction osteogenesis can be a valuable alternative for the treatment of juxta-articular nonunions.

Venous thromboembolism after spine surgery: changes of the fibrin monomer complex and D-dimer level during the perioperative period

OBJECT The goal of this study was to determine the incidence of deep venous thrombosis (DVT) and pulmonary embolism (PE) after spine surgery. Another purpose was to clarify the rapid changes of the fibrin monomer complex (FMC) and D-dimer levels during the perioperative period of spine surgery for early diagnosis of venous thromboembolism (VTE). METHODS The participants were 72 patients who underwent spine surgery between September 2007 and March 2008. The FMC and D-dimer levels were measured 6 times: 1) at induction of general anesthesia; 2) just after implantation or during surgery; 3) immediately following surgery; 4) 1 day after surgery; 5) 3 days postsurgery; and 6) 7 days after surgery. All patients received mechanical prophylaxis, including compression stockings and intermittent pneumatic compression devices, and all were examined with duplex ultrasonography assessments of both lower extremities and with lung perfusion scintigraphy 7-10 days after surgery. If DVT or PE was suspected, the patient underwent multidetector CT venography. RESULTS There were no patients with clinical signs of DVT and PE, but 6 (8.3%) showed VTE, among whom 5 had DVT and 3 had PE. Patients with VTE had significantly higher FMC levels 1 day after surgery, compared with those without VTE (55.9 ± 17.2 μg/ml vs 11.1 ± 2.89 μg/ml; p < 0.01). Patients with VTE had significantly higher D-dimer levels 7 days postsurgery, compared with those without VTE (12.5 ± 2.95 μg/ml vs 4.3 ± 0.39 μg/ml; p < 0.01). Receiver operating characteristic analysis showed that the FMC result was more useful than the D-dimer assay for diagnosis of VTE. When the cutoff value was set to 20.8 μg/ml for FMC, sensitivity was 100% and specificity was 86.3%. CONCLUSIONS In this study the prevalence of VTE after spine surgery was 8.3%. The FMC measured 1 day after spine surgery is considered to be useful as an indicator of VTE.

Vascular endothelial growth factor in rabbits during development of corticosteroid-induced osteonecrosis: a controlled experiment.

Objective Vascular endothelial growth factor (VEGF) is an angiogenic promoter that is rapidly induced as a response to local hypoxia. We investigated VEGF expression in rabbits in a controlled experiment to clarify the onset of ischemic events in corticosteroid-induced osteonecrosis (ON). Methods Ninety-nine mature Japanese white rabbits were divided into 6 treatment groups and an untreated control group. The treatment groups received a single intramuscular injection of 4 mg/kg methylprednisolone acetate; they were euthanized at different times, and tissue samples were obtained from their femora. We examined the development of ON and the expression of VEGF using histopathology, immunohistochemistry, Northern blot analysis, and Western blot analysis. Results On histopathological examination, the earliest indication of ON was 5 days after the corticosteroid treatment. The frequency of ON occurrence reached a plateau at or after Week 1. VEGF expression was accompanied by the development of ON. VEGF-positive cells detected by immunohistochemistry were found among bone marrow cells, frequently located in the area surrounding ON, suggesting that VEGF production was switched on as a result of the ischemic events that cause ON. The level of VEGF-mRNA expression indicated by Northern blot analysis peaked at 3 days after the corticosteroid treatment and decreased gradually to the levels present in the control group at 7 days after treatment. Western blot analysis revealed VEGF protein production at 3 days after the corticosteroid treatments. Levels of VEGF expression 2 weeks or more after the corticosteroid treatment were almost the same as in the control group. Conclusion We observed early expression of VEGF in the cells around the corticosteroid-induced ON lesions in rabbits. These results suggest that the ischemic events that cause ON begin soon after the initial corticosteroid treatment.

Changes of the soluble fibrin monomer complex level during the perioperative period of hip replacement surgery

BackgroundVenous thromboembolism (VTE) is a critical complication after hip replacement surgery, so both early diagnosis and prophylaxis are important. The purpose of this study was to clarify the rapid changes of the fibrin monomer complex (FMC) and soluble fibrin (SF) during the perioperative period of hip replacement surgery.MethodsThe subjects were 32 patients (7 men, 25 women) who underwent elective hip replacement surgery between November 2004 and January 2006. Their ages ranged between 34 to 82 years (mean 56.8 years). According to their thromboembolic risk, the patients received different prophylaxis: unfractionated heparin (4 patients), danaparoid sodium (14 patients), or mechanical therapy only (14 patients).ResultsFMC and SF became rapidly elevated during the operation and just after surgery but declined to preoperational levels 3 days after surgery; they were higher in lupus anticoagulant (LA)-positive patients. In contrast, FDP and D-dimer had gradually become elevated 3 and 7 days after surgery. According to venous ultrasonography and lung perfusion scintigraphy, VTE occurred in 7 patients overall (21.9%). The incidence of VTE was 7.1% in the danaparoid group, whereas it was 35.7% in the mechanical therapy group. We also found that danaparoid sodium rapidly decreased FMC and SF within 3 days.ConclusionsFMC and SF were rapidly elevated during hip replacement surgery and differentiated in LA-positive and LA-negative patients.

A Mechanical Analysis of Femoral Resurfacing Implantation for Osteonecrosis of the Femoral Head

Hip resurfacing is becoming a popular procedure for treating osteonecrosis of the femoral head. However, the biomechanical changes that occur after femoral resurfacing have not been fully investigated with respect to the individual extent of the necrosis. In this study, we evaluated biomechanical changes at various extents of necrosis and implant alignments using the finite element analysis method. We established 3 patterns of necrosis by depth from the surface of femoral head and 5 stem angles. For these models, we evaluated biomechanical changes associated with the extent of necrosis and the stem alignment. Our results indicate that stress distribution near the bone-cement interface increased with expansion of the necrosis. The maximum stress on the prosthesis was decreased with stem angles ranging from 130° to 140°. The peak stress of cement increased as the stem angle became varus. This study indicates that resurfacing arthroplasty will have adverse biomechanical effects when there is a large extent of osteonecrosis and excessive varus or valgus implantation of the prosthesis.

The use of the transverse acetabular ligament in total hip replacement: An analysis of the orientation of the trial acetabular component using a navigation system

It has recently been reported that the transverse acetabular ligament (TAL) is helpful in determining the position of the acetabular component in total hip replacement (THR). In this study we used a computer-assisted navigation system to determine whether the TAL is useful as a landmark in THR. The study was carried out in 121 consecutive patients undergoing primary THR (134 hips), including 67 dysplastic hips (50%). There were 26 men (29 hips) and 95 women (105 hips) with a mean age of 60.2 years (17 to 82) at the time of operation. After identification of the TAL, its anteversion was measured intra-operatively by aligning the inferomedial rim of the trial acetabular component with the TAL using computer-assisted navigation. The TAL was identified in 112 hips (83.6%). Intra-observer reproducibility in the measurement of anteversion of the TAL was high, but inter-observer reproducibility was moderate. Each surgeon was able to align the trial component according to the target value of the angle of anteversion of the TAL, but it was clear that methods may differ among surgeons. Of the measurements of the angle of anteversion of the TAL, 5.4% (6 of 112 hips) were outliers from the safe zone. In summary, we found that the TAL is useful as a landmark when implanting the acetabular component within the safe zone in almost all hips, and to prevent it being implanted in retroversion in all hips, including dysplastic hips. However, as anteversion of the TAL may be excessive in a few hips, it is advisable to pay attention to individual variations, particularly in those with severe posterior pelvic tilt. Cite this article: Bone Joint J 2014;96-B:306–11.It has recently been reported that the transverse acetabular ligament (TAL) is helpful in determining the position of the acetabular component in total hip replacement (THR). In this study we used a computer-assisted navigation system to determine whether the TAL is useful as a landmark in THR. The study was carried out in 121 consecutive patients undergoing primary THR (134 hips), including 67 dysplastic hips (50%). There were 26 men (29 hips) and 95 women (105 hips) with a mean age of 60.2 years (17 to 82) at the time of operation. After identification of the TAL, its anteversion was measured intra-operatively by aligning the inferomedial rim of the trial acetabular component with the TAL using computer-assisted navigation. The TAL was identified in 112 hips (83.6%). Intra-observer reproducibility in the measurement of anteversion of the TAL was high, but inter-observer reproducibility was moderate. Each surgeon was able to align the trial component according to the target value of the angle of anteversion of the TAL, but it was clear that methods may differ among surgeons. Of the measurements of the angle of anteversion of the TAL, 5.4% (6 of 112 hips) were outliers from the safe zone. In summary, we found that the TAL is useful as a landmark when implanting the acetabular component within the safe zone in almost all hips, and to prevent it being implanted in retroversion in all hips, including dysplastic hips. However, as anteversion of the TAL may be excessive in a few hips, it is advisable to pay attention to individual variations, particularly in those with severe posterior pelvic tilt.

Histological finding of atypical subtrochanteric fracture after long-term alendronate therapy

Abstract Drug therapy for osteoporosis is widely accepted. Bisphosphonates in particular significantly inhibit bone resorption by suppressing osteoclast activity and increasing bone density [1–3]. Alendronate is one of these bisphosphonates; it was approved in the United States in the 1990s and is commonly prescribed worldwide [1, 4, 5]. Clinical trials have shown its effectiveness in the treatment of fractures related to postmenopausal osteoporosis [6]. However, some recent reports have described unusual subtrochanteric or femoral shaft fractures following long-term alendronate therapy [4, 7–13]. Although no causal relationship between long-term alendronate treatment and these atypical stress fractures has been established, some reports suggest that the severe suppression of bone turnover by alendronate may lead to accumulated microdamage to the bone that subsequently results in complete fracture [4, 12].

Does Degree of the Pelvic Deformity Affect the Accuracy of Computed Tomography-Based Hip Navigation?

Although some navigation systems have been used for improvement of component positioning, there have been few reports regarding cases of severe pelvic deformity. We performed a retrospective review of 25 cases of total hip arthroplasty with a computed tomography-based navigation system in patients with severe pelvic deformities and estimated acetabular component position and angle between severe deformity group and mild dysplastic group as a control. There were no significant differences in accuracy of navigation system between 2 groups in terms of 3-dimensional component position or angle. Accuracy of computed tomography-based hip navigation does not depend on the degree of pelvic deformity, and this system is also useful to identify acetabular orientation and for precise component implantation in cases of pelvic deformity.