Alendronate does not prevent long bone fragility in an inactive rat model.

The lack of estrogen and inactivity are both important in the pathogenesis of osteoporosis in elderly women, and there have been no appropriate rodent studies to examine the effects of common bisphosphonates on these two components separately. We compared the efficacy of alendronate (ALN) on the long bones of aged female rats, which were sedentary, estrogen deficient, or both. The rats were either forced to remain in a sitting position or allowed to walk in standard cages with or without ALN administration. The 8-week experimental period began 5 weeks after ovariectomy or sham surgery. Parameters of the hindlimb bones were determined by a three-point bending test, peripheral quantitative computed tomography, microfocus computed tomography, confocal laser Raman microspectroscopy, and dynamic histomorphometry. Regardless of ovariectomy, ALN was ineffective against the deterioration of breaking stress caused by sitting even though the trabecular bone mineral density was significantly higher in the sitting-ALN groups. Toughness was significantly deficient in the ovariectomy sitting-ALN group. This was in agreement with the bone geometry with a greater marrow space. Sitting also increased the mineral-to-matrix ratio and the carbonate-to-phosphate ratio, both indicative of aged bone. A greater loss of proteinaceous amide intensity compared with mineral intensity resulted in an increased mineral-to-matrix ratio in the presence of ALN. Sitting resulted in deficits in the quality and the geometry of cortical bone, resulting in fragility. The use of bisphosphonates, such as ALN, may provide a therapy best suited for osteoporotic individuals whose daily activity is not limited.

Discrepancy between anatomical axis and stem position of various femoral components in Japanese.

PURPOSE: To evaluate the discrepancy between the anatomical axis of the distal femur of Japanese patients and the stem position of 5 types of femoral components. METHODS: Lateral radiographs of 12 men and 88 women aged 31 to 83 (mean, 59) years with rheumatoid arthritis were evaluated. The discrepancy between the anatomical axis of the distal femur and the stem position of 5 types of femoral components (Nexgen LCCK, Press-Fit Condylar, Scorpio, Total Stabilizer, and Rotating Hinge) was determined by superimposing the template of each model over each lateral radiograph. RESULTS: The anatomical axis varied widely among our patients, as did the stem position of the 5 femoral components. Stems of all 5 femoral components tended to be more posterior than the anatomical axis. The discrepancy was smallest in the Nexgen LCCK, followed by the Press-Fit Condylar components. It was >3 mm in the other 3 models. In 35% of the patients, none of the prosthesis could be placed in an appropriate position. Smaller-size prostheses appear necessary for the Japanese. CONCLUSION: The stem position should be an important factor guiding selection of the appropriate model. The currently available femoral components may not be appropriate for the Japanese. Prostheses with appropriately positioned stems for Japanese patients with rheumatoid arthritis should be developed.

Morphologic differences of the distal femur between Caucasian and Japanese women.

PURPOSE: To compare the morphology of the distal femur between Caucasian and Japanese women. METHODS: 30 Caucasian women aged 41 to 84 (mean, 67) years and 70 Japanese women aged 54 to 86 (mean, 70) years who underwent total knee arthroplasty for osteoarthritis were randomly selected. Morphologic measurements of the distal femur were compared using lateral radiographs. Both race and height influenced the morphology. To adjust for the influence of height on morphology, each measurement was divided by the patient's height and the ratios were compared. RESULTS: Caucasian women were generally taller and heavier (p<0.001) and had higher body mass index (p=0.03) than the Japanese women. Each morphologic measurement of the distal femur was significantly longer in the Caucasian women. In both groups, anteroposterior width of the condyle correlated more with height than weight. In women of equal height, the anteroposterior and metaphyseal widths of the femur and the anterior and resected condyles were longer in Caucasian women, but the posterior condyle was longer in Japanese women. CONCLUSION: Both the size of the femur and the anterior and posterior condyles are significantly larger in Caucasian than Japanese women.

Anatomic study for pubic medullary screw insertion.

PURPOSE: To study the anatomy of the pubic ramus and adjacent structures in 160 Japanese to establish a safer pubic screw fixation technique. METHODS: 80 male and 80 female Japanese aged 16 to 89 (mean, 50) years (10 persons in each decade of age) underwent 3-dimensional computed tomographic scanning of their pelvises. The angle at which the screw should be targeted, the appropriate length of the screw, the size of the canal for screw insertion, and the proximity to the bladder, iliac artery, and iliac vein were determined. Correlations between the canal diameters (of the acetabular, base, and parasymphyseal areas) and body features (age, height, and weight) were analysed. RESULTS: In men and women respectively, the appropriate mean screw length was 124.6 and 123.8 mm; the guide wire should be targeted at a mean of 66 degrees and 67 degrees cephalad and 54.1 degrees and 55.9 degrees laterally for insertion of a retrograde pubic screw; the minimum distances from the pubis to the bladder/iliac artery/ iliac vein were 0 and 0 mm/4.9 and 4.6 mm/0.8 and 0.2 mm. In both men and women, the canal diameters at the base were positively correlated to weight. In women, the canal diameters at the parasymphyseal area were correlated to height and weight. Canal diameters at the acetabulum were not correlated to height and weight. CONCLUSION: Pubic screw fixation may be potentially disastrous (owing to joint penetration and iliac vein injury) and should be performed with caution. When the canal diameter at the acetabulum is extremely narrow, plate fixation, computer-assisted surgery, or changing to a smaller-diameter screw is recommended.

Comparison of the cytokine-induced migratory response between primary and subcultured populations of rat mesenchymal bone marrow cells.

BACKGROUND: The aim of this study was to investigate the phenotypic differences of primary rat mesenchymal bone marrow cells (MBMCs) and subcultured cells, the influence of subculture and cell density on the cellular phenotypes, and the difference in the migratory responses of these cells to cytokines. METHODS: MBMCs were isolated from 8-week-old Wistar rats, and the cells were cultured for 1 week (passage 0, P0) or 3 weeks (P0-3W). P0 cells were subcultured for 1 week (P1). P1 cells were subcultured at several cell densities for 1 week (P2). Cell size and granularity were analyzed by flow cytometry. The gene expression characteristics of these cells were analyzed by reverse transcription polymerase chain reaction. Cell migration to bone morphogenetic protein-2 (BMP-2), fibroblast growth factor-2 (FGF-2), and platelet-derived growth factor-bb (PDGF-bb) was evaluated using a Boyden chamber. RESULTS: Three morphologically distinct populations in P0 and two in P2 were detected. The levels of human rapidly self-renewing cell-related marker genes in P0 were more highly expressed than in P2. Mesenchymal stem cell-associated markers were expressed at the same level in P0 and P2. The gene expression levels of immature oligodendrocyte precursor cell markers in P0 were higher than those in P2, whereas those of smooth muscle cell markers and osteoblastic cell markers in P0 were lower than those in P2. Subculture decreased the gene expression levels of human rapidly self-renewing cell-associated markers. Cell migration of P0 cells was stimulated by PDGF-bb but not by BMP-2 or FGF-2. In contrast, PDGF-bb, BMP-2, and FGF-2 all stimulated cell migration of P2. CONCLUSION: The types of cells in populations of primary and subcultured rat MBMCs were different, and the distribution of each cell population appeared to be changed by the culture conditions. The cell migration effect by PDGF-bb, BMP-2, and FGF-2 differed between the primary and subcultured MBMCs.

Immediate interlocking nailing versus external fixation followed by delayed interlocking nailing for Gustilo type IIIB open tibial fractures.

PURPOSE: To compare immediate interlocking nailing with external fixation followed by delayed interlocking nailing, for Gustilo type IIIB open tibial fractures. METHODS: 23 patients with Gustilo IIIB open tibial fractures were treated with either immediate unreamed interlocking nailing (n=9) or external fixation followed by delayed unreamed interlocking nailing (n=14). Patient age, sex ratio, fracture site, fracture type, and severity were similar in both groups. The time to union, deep infection rate, and nonunion rate in the 2 groups were compared. RESULTS: In the immediate and delayed nailing groups, respective mean times to union were 21 (standard deviation [SD], 14) months and 14 (SD, 8) months; nonunion rates were 44% (4/9) and 36% (5/14), and deep infection rates were 22% (2/9) and 7% (1/14). All corresponding differences were not statistically significant. CONCLUSION: Prospective, randomised, multicentre studies are needed to assess whether there are significant differences between the 2 treatment methods.

Protective effect of ischaemic preconditioning against ischaemia-induced reperfusion injury of skeletal muscle: how many preconditioning cycles are appropriate?

We investigated the efficacy of ischaemic preconditioning (IPC), consisting of repeated brief episodes of vascular occlusion followed by reperfusion, as protection against ischaemia-reperfusion injury of skeletal muscle, using a rat amputation-like model. Wistar rats underwent temporary amputation at the level of the femur, excluding the femoral vessels. The femoral artery and vein were clamped for 4h, using a micro-clamp, in the groups exposed to ischaemia. The rats were randomly divided into eight groups: a control (C) group (n = 7) with non-amputated and non-ischaemic hind limbs; a sham control (SC) group (n = 7) with amputated but non-ischaemic hind limbs; an ischaemia-reperfusion (IR) group (n = 7) with amputated and ischaemic hind limbs; and five IPC groups (n = 7 in each) with hind limbs that were subjected to 4h of ischaemia after one to five cycles of brief ischaemia and reperfusion for 10 min each, respectively. All rats were sacrificed 24h after reperfusion. The viability of the anterior tibial muscles was evaluated using nitroblue tetrazolium staining. The total viable area ratio (T-VAR) of the muscle tissue was calculated in each animal as follows: T-VAR\total viable area/total slice areae 100%. The T-VAR values of the eight groups were as follows: C group, 100% +/- 0%; SC group, 100% +/- 0%; IR group, 73.5% +/- 1.7%; IPC1 group, 79.4% +/- 6.5%; IPC2 group, 70.5% +/- 6.2%; IPC3 group, 90.6% +/- 2.8%; IPC4 group, 90.0% +/- 1.6%; and IPC5 group, 87.8% +/- 1.8%. The T-VARs in the IPC3, IPC4 and IPC5 groups were significantly higher (alpha < 0.01) than those in the IR group. In contrast, there were no significant differences between the T-VARs of the IPC1 and IPC2 groups and those of the IR group. In conclusion, three to five cycles of IPC could protect skeletal muscle against ischaemia. 2002 The British Association of Plastic Surgeons.

Technique for removing a bent intramedullary femoral nail: a case report.

The authors present a case in which an interlocked intramedullary nail placed to secure a left femoral shaft fracture was deformed twelve months after surgery because of secondary trauma. The nail was straightened by sectioning through half of its diameter with a drill for metal under minimal soft tissue dissection, then removed and replaced with another nail. The femur subsequently healed without complications.

Changes in nitric oxide, superoxide, and blood circulation in muscles over time after warm ischaemic reperfusion in rabbit rectus femoris muscle.

We present the sequence of changes in nitric oxide (NO) and superoxide (O2-) over time in reperfusion injuries. We examined both the changes in NO and O2- over time and the blood flow in an isolated ischaemia-reperfusion muscle model in rabbits. The ischaemic group comprised 8 animals which had had vascular pedicles clamped on the their rectus femoris muscles for 4 hours. The control group (n = 6) had a sham operation. Blood samples from the femoral vein proximal to the clamping point were collected before the operation, before clamping, before reperfusion, immediately after reperfusion, and 5, 15, 30, 60, and 120 minutes after reperfusion. NO was measured by Griess' method, and O2- by chemiluminescence. Blood flow was measured with a laser Doppler flowmeter. The amount of NO increased significantly immediately after reperfusion, and 15 and 30 minutes after reperfusion in the ischaemic group, compared with the control group (p < 0.05). O2- increased significantly at 5, 15, 60, 90 and 120 minutes after reperfusion, compared with the control group (p < 0.05). The blood flow volume curve increased by 1.4 times about four minutes after reperfusion compared with previously. After this it gradually decreased. The adverse effects of O2- became apparent when NO was extinguished by O2-.

Free vascularized fibular graft vs. Ilizarov method for post-traumatic tibial bone defect.

From 1991 to 1996, four free vascularized fibular grafts (FVFG) and four callus distraction (CD) techniques were performed for post-traumatic tibial defects at the authors' institute. They attempted to discern any differences of results between FVFGs and CDs for post-traumatic tibial defects. The mean defect length of the FVFG and CD groups were 7.3 cm and 4.6 cm, respectively (p < 0.05). They selected as contributing factors: external fixation time, complication rate, hospital charge, union rate, and functional score (Puno's criteria), in order to compare the treatment of FVFG with that of CD. The external fixation times of the FVFG and CD groups were 176 days and 261 days, respectively. One septic non-union after refracture of the grafted fibula occurred in the FVFG group. Two non-unions (50 percent) at the docking site occurred in the CD group. The mean total costs of the FVFG and CD groups were 7,398,536 yen (US $68,505) and 11,798,153 yen(US $109,242), respectively. The union rates of both groups were 75 percent and 100 percent, respectively. The mean functional scores of both groups were 69.5 and 88.8 points, respectively. The functional results of the FVFG group were as follows: one patient showed good results; one, fair; and two, poor. The functional results of the CD group were as follows: two patients showed excellent results; one, good; and one, fair. Both the costs and the functional outcomes between the two groups did not significantly differ. No clear differences between the two treatment groups could be determined. However, many more cases are needed to establish statistically significant differences between both methods.

Gluteal muscle necrosis following transcatheter angiographic embolisation for retroperitoneal haemorrhage associated with pelvic fracture.

Transcatheter angiographic emobilisation has been used as an effective control of haemorrhage associated with pelvic fracture. Although few complications of this procedure have been reported, gluteal muscle necrosis occurs occasionally. We assessed the type of pelvic fracture, concomitant injury, embolic site, embolic materials, and outcome in cases of gluteal muscle necrosis associated with angiographic embolisation for pelvic fracture-related haemorrhage, and investigated the factors associated with the development of gluteal muscle necrosis, one of the fatal complications of transcatheter angiographic embolisation. Five out of the 151 patients (incidence, 3.3%) who underwent transcatheter angiographic embolisation for haemorrhagic shock due to pelvic fracture developed gluteal muscle necrosis after embolisation. The five cases had injury severity scores ranging from 26 to 59 (mean 46.4). Three patients died (mortality, 60%) of subsequent sepsis and disseminated intravascular coagulation. These cases showed that transcatheter angiographic embolisation with gelatin sponge and/or steel coil, while effectively controlling bleeding, may also result in gluteal muscle necrosis. Aggressive management including intraarterial antibiotic treatment may have a role, but our numbers are too small to confirm this.

Contributing factors influencing the functional outcome of floating knee injuries.

The purpose of the present study was to retrospectively review the floating knee injuries treated at our institute and to determine various factors, such as severity of soft-tissue or skeletal injuries, site of fractures, and treatment methods that may significantly influence the final functional result in these injuries. Between 1986 and 1996, 65 patients with 66 floating knee injuries were treated in our institution. Among 66 fractures of the femur, 19 (29%) were open. There were 43 open tibial fractures. Fifty cases were Fraser type I floating knee fractures, 7 were type IIa, 2 were type IIb, and 7 were type IIc. In 63 cases (95%), both bones had been surgically stabilized with interlocked nails, Ender pins, plates, screws with/without pinning, or external fixations. Final functional results were evaluated according to Karlström and Olerud's criteria. Satisfactory results were rated as cases with excellent or good results. The mean follow-up time was 16.6 months range, (12-50 months). We assessed various factors influencing functional results, including Fraser type, severity of open injury grade (Gustilo) in both fractures, combination of open/closed injuries, fracture types (AO/ASIF type), existence of multiple trauma, neurovascular injuries, polyskeletal trauma, and stabilizing method or operation timing of both fractures. Satisfactory rates in Fraser type I and type II were 64% and 25%, respectively (P= .02). The satisfactory rate in closed, grade I+II, and grade III injuries of the femoral fractures was 53.2%, 81.8%, and 25%, respectively (grade I+II vs. grade III: P < .03). There were no significant correlations between the functional result and the following factors: soft-tissue injuries of the tibia; the fracture pattern of both fractures; the combination of open/closed injuries in each fracture; injury severity score; the existence of neurovascular injuries and double femoral fractures; treatment methods; and operation timing. Severity of damage to the knee joint and open injuries in the thigh were found to be significant factors contributing to the functional outcome in floating knee injuries.

Time course of superoxide anion radicals generation in two ischaemia-reperfusion models: comparison between hindlimb replant model and isolated rectus femoris muscle model.

We examined differences in superoxide radical (O(2)(-)) production between a hindlimb replant model and isolated rectus femoris muscle model using rabbits. Using Japanese white rabbit hindlimbs, we made limb replant models (LR group: n = 10) and isolated rectus femoris muscle models (IM group: n = 8) by temporary 4-h clampings of femoral vessels and nutrient vessels, respectively. For sham control subjects, the same surgical procedures with no clampings in both models were done (Control-LR: n = 7, Control-IM: n = 6). The measurement of O(2)(-)was performed by our chemiluminescence (CLN) method. In both models, reperfused blood samples were collected before reperfusion, and 5, 15, 30 and 60 min after reperfusion, and CLN was measured. We defined the superoxide index (SI) in each individual specimen as post-reperfusion CLN/pre-reperfusion CLN. The time course of SI in the Control-LR group was significantly higher than that of SI in the Control-IM group (P< 0.05). There was no significant difference between the time course of SI in the LR group and that of SI in the IM group. Both the limb replant model and isolated muscle model are applicable for the evaluation of radical formation in the reperfused stage though there are potential differences between the two models caused by the surgical procedures themselves.

Growth factor expression in the osteophytes of the human femoral head in osteoarthritis.

Osteoarthritis is characterized by marked osteophyte formation consisting of new cartilage and bone. Because several growth factors are known to be involved in chondrogenesis and osteogenesis, the expression of transforming growth factor-beta 1 and basic fibroblast growth factor in the osteophytes of the human femoral heads in osteoarthritis were examined. Transforming growth factor-beta 1 messenger ribonucleic acid was detected in the osteophytes by reverse transcription-polymerase chain reaction. All of the nine examined osteophytes expressed transforming growth factor-beta 1 messenger ribonucleic acid, whereas one of four osteoarthritic femoral heads and none of four osteonecrotic femoral heads expressed transforming growth factor-beta 1 messenger ribonucleic acid. The extent of transforming growth factor-beta 1 messenger ribonucleic acid expression varied among the osteophytes. Transforming growth factor-beta 1 or basic fibroblast growth factor was analyzed in osteophytes immunohistochemically. Transforming growth factor-beta 1 was localized in the superficial cells in the osteophyte cartilage, but it was scarcely detected in the superficial cells in the degenerative articular cartilage. Basic fibroblast growth factor was detected in the cells in the whole layer of osteophyte cartilage and in the articular cartilage. There was a difference in the localization, which suggests the different roles of transforming growth factor-beta 1 and basic fibroblast growth factor in bone and cartilage metabolism in osteophyte formation.

Involvement of cyclins in cell proliferation and their clinical implications in soft tissue smooth muscle tumors.

Expression of cyclins A and E and cyclin-dependent kinase 2 (cdk2) was examined immunohistochemically in 55 cases of soft tissue smooth muscle tumors, including vascular leiomyoma, and compared to expression of Ki-67 and proliferating cell nuclear antigen. Cyclin A was expressed in 70% of the leiomyoma cases, but with much lower labeling indexes than in leiomyosarcoma. Cyclin E was expressed exclusively in leiomyosarcoma. Although the differences of cyclin A- and cyclin E-labeling indexes between leiomyoma and leiomyosarcoma were statistically significant, no significant differences were found in the other markers. Furthermore, cyclin A- and/or E-positivity predicted a poor prognosis in recurrence- or metastasis-free survivals and overall survival. Immunoblotting revealed that cyclins A and E were expressed, in complex with cdk2, exclusively in tumors. In addition, not only leiomyosarcoma, but also leiomyoma specimens that exhibited negligible levels of complex expression, manifested detectable cdk2 activity. These results suggest 1) up-regulation of active cyclin A/cdk2 expression and associated kinase activity is critical for unrestrained cell proliferation; 2) cyclin E/cdk2 complexes may play a crucial role in leiomyosarcoma; 3) immunohistochemical detection of cyclins can be a more reliable tool for differential diagnosis between leiomyoma versus leiomyosarcoma than that of Ki-67 or proliferating cell nuclear antigen, and be a possible prognostic indicator.

Anabolic response of mouse bone-marrow-derived stromal cell clone ST2 cells to low-intensity pulsed ultrasound.

The effects of 20-min exposure to low-intensity, pulsed ultrasound were investigated in ST2 cells of bone marrow stromal origin. They responded to ultrasound with elevated levels of IGF mRNAs, osteocalcin, and bone sialoprotein mRNAs. The upregulated expression of these messages appeared in a biphasic manner, with the first peak resistant to the protein synthesis inhibitor cycloheximide, and a second peak that was eliminated by NS398, an inhibitor of the inducive prostaglandin G/H synthase (cyclooxygenase-2). A cumulative effect of mechanical loading called the memory effect, which has been observed in vivo, can be explained from such a biphasic anabolic reaction mediated by prostaglandins. The upregulation of IGF or osteocalcin mRNAs can be observed even at 24 h after the initiation of the 20-min exposure to ultrasound. Our results suggest that this low-intensity, pulsed ultrasound, which has been clinically used to accelerate the healing processes of fractured bone, induces a direct anabolic reaction of osteogenic cells, leading to bone matrix formation.

Chondrocyte transplantation for osteochondral defects with the use of suspension culture.

Cartilage graft is considered to be useful in repairing chondral or osteochondral defects. One method of the cartilage graft is achieved by autologous chondrocyte transplantation following cell culture. However, chondrocytes change their phenotype during culture. We used costal chondrocytes cultured over agarose (suspension culture) as a source of graft materials. The suspension-cultured chondrocytes formed aggregate in culture. We first examined the expressions of cartilage-specific matrices of cultured chondrocytes after two weeks in culture. The chondrocytes cultured over agarose expressed more type II collagen mRNA than those cultured on plastic dishes did after two weeks in culture. Safranin O staining showed the presence of glycosaminoglycans in the chondrocyte culture over agarose, while glycosaminoglycans were not observed in the culture on plastic dishes. We then examined the changes of rat articular osteochondral defects after transplantation of suspension-cultured chondrocytes. The aggregate of suspension-cultured chondrocytes was easily picked up with forceps and transplanted in the osteochondral defects. The defects were filled with safranin O-stained hyaline cartilage tissue two weeks after chondrocyte transplantation. On the contrary, the fibrous materials, which were not stained with safranin O, were observed in the control defects. These results suggest that the suspension-cultured chondrocytes are useful for autologous cartilage grafts by preserving chondrocyte phenotype.

Cortical revascularization after reamed and unreamed intramedullary nailing in the rabbit femur: a microangiographic histometric analysis.

BACKGROUND: Intramedullary nailing leads to a reduction in cortical bone blood flow. The relative effect of reamed versus unreamed nailing on the degree of avascularity and on revascularization of the cortex remains controversial. We compared the effects of reamed versus unreamed intramedullary nailing on cortical revascularization and the time course for its recovery in the unfractured rabbit femur. METHODS: A total of 56 New Zealand white rabbits were used as experimental animals. Reamed nailings with Kirschner wire (diameter, 3 mm) were performed in the right femora (group R, n = 49), and unreamed nailings with Kirschner wire (diameter, 2 mm) were performed in the left femora (group UR, n = 49) of the same animals after a standard surgical procedure. Microangiography that used Indian ink was performed for each killed animal at one of seven postoperative time periods: 2 hours, 3 days, and 1, 2, 3, 4, and 5 weeks after surgery. The right femora and the left femora of seven rabbits were used as the postoperative day 0 controls of group R and those of group UR, respectively. We evaluated the vascularization ratio (VR) in cross-sections according to the following formula: VR = the number of enhanced vessels with Indian ink/total cortical vessels. Each cross-section was divided into an inner and outer half, which were in turn divided into quarters, so that the entire cross-sectional are is represented by eight regions. The VR was calculated for each regions and then comparison was made between group R and group UR at various time periods and areas. RESULTS: No statistically significant differences were observed in VR at any time period between group R and group UR in total cortical area and total periosteal side. However, on the total medullary side, the VR of group UR was significantly higher than that of group R at postoperative day 3 (p = 0.04). Statistically significant differences were observed between the VR on the periosteal side and that on the medullary side in both groups at all time periods aside from the 5-week period (p < 0.05). Revascularization of the cortex occurred 4 weeks after intramedullary nailing in both group R and group UR. CONCLUSION: The periosteal circulation was maintained better than the medullary circulation, irrespective of whether the canal was reamed or not. The present study failed to detect any statistically significant differences in cortical revascularization between reamed nailing and unreamed nailing. Thus, we concluded that reamed and unreamed nailing are not differentially advantageous in the unfractured rabbit femur, in terms of impairment of cortical blood supply.

Deep infection and fracture healing in immediate and delayed locked intramedullary nailing for open femoral fractures.

Fifty-nine patients with 61 open femoral fractures were treated with immediate locked intramedullary (IM) nailing (group 1; n=15), delayed IM nailing following nonoperative treatment (group 2; n=42), and delayed IM nailing following external fixation (group 3; n=7). Sixteen fractures were Gustilo type I, 28 were type II, 7 were type IIIA, 6 were type IIIB, and 4 were type IIIC open fractures. Four (6.6%) deep infections occurred. Significant differences existed in the deep infection rate (DIR) between types I and II and all type III fractures (2.3% for types I and II versus 17.6% for type III). The deep infection rate did not differ significantly among the nailing groups (13.3%, 2.6%, and 15.3% for groups 1, 2, and 3, respectively), nor did the deep infection rate correlate with the degree of fracture comminution, the existence of polytrauma or polyskeletal trauma, or preexistence of superficial or pin-site infections. Seven (11.7%) of these fractures resulted in nonunion, excluding one secondary amputation; the nonunion rate correlated with fracture location. There were no significant differences in the mean fracture healing times between any of the nailing groups. These results suggest that IM nailing for the treatment of type III open femoral fractures should be considered carefully, regardless of whether it is performed immediately or delayed.

Time course of post-ischemic superoxide generation in venous effluent from reperfused rabbit hindlimbs.

In order to clarify the early time course of the generation of O2- produced from reperfused extremities after ischemia, the authors directly quantified the O2- of venous effluent from reperfused hindlimbs following various time periods of warm ischemia, using a rabbit reperfusion model. Using a total of 30 rabbit hindlimbs, the hindlimb-reperfusion model was created by temporarily cutting both soft-tissue and bony structures, exclusive of femoral vessels, around the thighs, and clamping the vessels with a microvascular clip. The various vascular pedicle clamping times at normothermia (25 degrees C) were used for three animal groups: 2-hr (n = 10), 4-hr (n = 10), and 6-hr (n = 10). For sham-operated controls (n = 7), the same surgical procedures with no clamping were performed. Venous effluent blood samplings from the femoral vein at the proximal side of the clamping point were collected before reperfusion, and from 5 min to 60 min after reperfusion at 5-min intervals in each animal, and peripheral blood was sampled to quantify O2- by a chemiluminescence (CLN) method using a derivative of luciferin (CLA). The time course of the production of O2- during reperfusion of all three experimental groups and controls showed polyphasic patterns with two or three peaks, but no significant changes throughout reperfusion. The time course of superoxide production after reperfusion in the 2-hr, 4-hr, and 6-hr groups showed significant differences (p < 0.05) in repeated measures by ANOVA, compared with controls. Superoxide production in the 6-hr group was greater than controls at relatively late times of reperfusion (20 min, 30 min, and 40 to 55 min after reperfusion). In the present study, it was found that the time course of superoxide production in ischemia-induced reperfused limbs showed a late polyphasic pattern without a significant initial peak, especially in the 6-hr ischemia group. In addition, the amount of superoxide production correlated with ischemic time period to some extent.