Enhancing the Repair of Substantial Volumetric Muscle Loss by Creating Different Levels of Blood Vessel Networks Using Pre-Vascularized Nerve Hydrogel Implants

Volumetric muscle loss (VML), a severe muscle tissue loss from trauma or surgery, results in scarring, limited regeneration, and significant fibrosis, leading to lasting reductions in muscle mass and function. A promising approach for VML recovery involves restoring vascular and neural networks at the injury site, a process not extensively studied yet. Collagen hydrogels have been investigated as scaffolds for blood vessel formation due to their biocompatibility, but reconstructing blood vessels and guiding innervation at the injury site is still difficult. In this study, collagen hydrogels with varied densities of vessel-forming cells are implanted subcutaneously in mice, generating pre-vascularized hydrogels with diverse vessel densities (0-145 numbers/mm2) within a week. These hydrogels, after being transplanted into muscle injury sites, are assessed for muscle repair capabilities. Results showed that hydrogels with high microvessel densities, filling the wound area, effectively reconnected with host vasculature and neural networks, promoting neovascularization and muscle integration, and addressing about 63% of the VML.

Engineering large and geometrically controlled vascularized nerve tissue in collagen hydrogels to restore large-sized volumetric muscle loss

Developing scalable vascularized and innervated tissue is a critical challenge for the successful clinical application of tissue-engineered constructs. Collagen hydrogels are extensively utilized in cell-mediated vascular network formation because of their naturally excellent biological properties. However, the substantial increase in hydrogel contraction induced by populated cells limits their long-term use. Previous studies attempted to mitigate this issue by concentrating collagen pre-polymer solutions or synthesizing covalently crosslinked collagen hydrogels. However, these methods only partially reduce hydrogel contraction while hindering blood vessel formation within the hydrogels. To address this challenge, we introduced additional support in the form of a supportive spacer to counteract the contraction forces of populated cells and prevent hydrogel contraction. This approach was found to promote cell spreading, resist hydrogel contraction, control hydrogel/tissue geometry, and even facilitate the engineering of functional blood vessels and host nerve growth in just one week. Subsequently, implanting these engineered tissues into muscle defect sites resulted in timely anastomosis with the host vasculature, leading to enhanced myogenesis, increased muscle innervation, and the restoration of injured muscle functionality. Overall, this innovative strategy expands the applicability of collagen hydrogels in fabricating large vascularized nerve tissue constructs for repairing volumetric muscle loss (∼63 %) and restoring muscle function.

Reconstructing vascular networks promotes the repair of skeletal muscle following volumetric muscle loss by pre-vascularized tissue constructs

Current treatment for complex and large-scale volumetric muscle loss (VML) injuries remains a limited success and have substantial disadvantages, due to the irreversible loss of muscle mass, slow muscle regeneration, and rapid formation of non-functional fibrosis scars. These VML injuries are accompanied by denervation and the destruction of native vasculature which increases difficulties in the functional restoration of muscle. Here, reconstruction of the vascular network at the injury site was offered as a possible solution for improving the repair of muscle defects through the timely supply of nutrients and oxygen to surrounding cells. A hydrogel-based tissue construct containing various densities of the vascular network was successfully created in the subcutaneous space of mice by manipulating hydrogel properties, and then implanted into the VML injury site. One month after implantation, the mouse treated with the highly vascularized tissue had extensive muscle repair at the injury site and only spent a shorter time completing the inclined plane tests. These findings suggest that the reconstruction of the functional vascular network at the VML injury site accelerated muscle fiber repair through a timely supply of sufficient blood and avoided invasion by host fibroblasts.

Strategy for improving cell-mediated vascularized soft tissue formation in a hydrogen peroxide-triggered chemically-crosslinked hydrogel

The physically-crosslinked collagen hydrogels can provide suitable microenvironments for cell-based functional vascular network formation due to their biodegradability, biocompatibility, and good diffusion properties. However, encapsulation of cells into collagen hydrogels results in extensive contraction and rapid degradation of hydrogels, an effect known from their utilization as a pre-vascularized graft in vivo. Various types of chemically-crosslinked collagen-based hydrogels have been successfully synthesized to decrease volume contraction, retard the degradation rate, and increase mechanical tunability. However, these hydrogels failed to form vascularized tissues with uniformly distributed microvessels in vivo. Here, the enzymatically chemically-crosslinked collagen-Phenolic hydrogel was used as a model to determine and overcome the difficulties in engineering vascular networks. Results showed that a longer duration of inflammation and excessive levels of hydrogen peroxide limited the capability for blood vessel forming cells-mediated vasculature formation in vivo. Lowering the unreacted amount of crosslinkers reduced the densities of infiltrating host myeloid cells by half on days 2–4 after implantation, but blood vessels remained at low density and were mainly located on the edge of the implanted constructs. Co-implantation of a designed spacer with cell-laden hydrogel maintained the structural integrity of the hydrogel and increased the degree of hypoxia in embedded cells. These effects resulted in a two-fold increase in the density of perfused blood vessels in the hydrogel. Results agreed with computer-based simulations. Collectively, our findings suggest that simultaneous reduction of the crosslinker-induced host immune response and increase in hypoxia in hydrogen peroxide-triggered chemically-crosslinked hydrogels can effectively improve the formation of cell-mediated functional vascular networks.

A strategy to engineer vascularized tissue constructs by optimizing and maintaining the geometry

The success of engineered tissues is limited by the need for rapid perfusion of a functional vascular network that can control tissue engraftment and promote survival after implantation. Diabetic conditions pose an additional challenge, because high glucose and lipid concentrations cause an aggressive oxidative environment that impairs vessel remodeling and stabilization and impedes integration of engineered constructs into surrounding tissues. Thus, to achieve rapid vasculogenesis, angiogenesis, and anastomosis, hydrogels incorporating cells in their structure have been developed to facilitate formation of functional vascular networks within implants. However, their transport diffusivity decreases with increasing thickness, preventing the formation of a thick vascularized tissue. To address this, we used diffusion-based computational simulations to optimize the geometry of hydrogel structures. The results show that the micro-patterned constructs improved diffusion, thus supporting cell viability, and spreading while retaining their mechanical properties. Thick cell-laden bulk, linear, or hexagonal infill patterned hydrogels were implanted; and structural stability due to skin mobility was improved by the protective spacer. Larger and thicker perfused vascular networks formed in the hexagonal structures (∼17 mm diameter, ∼1.5 mm thickness) in both normal and diabetic mice on day 3, and they became functional and uniformly distributed on day 7. Moreover, transplanted islets were rapidly integrated subcutaneously in this engineered functional vascular bed, which significantly enhanced islet viability and insulin secretion. In summary, we developed a promising strategy for generating large, thick vascularized tissue constructs, which may support transplanted islet cells. These constructs showed potential for engineering other vascularized tissues in regenerative therapy. STATEMENT OF SIGNIFICANCE: Diffusion-based computational simulations were used to optimize the geometry of hydrogel structures, i.e., hexagonal cell-laden hydrogels. To maintain the hydrogel's structural integrity, a spacer was designed and co-implanted subcutaneously to increase the permeability of explants. The spacer provides the structural integrity to improve the permeability of the implanted hydrogel. Otherwise, the implanted hydrogel may be easily squeezed and deformed by compression from the skin mobility of mice. Here, we successfully developed a cell-based strategy for rapidly generating large, functional vasculature (diameter ∼17 mm and thickness ∼1.5 mm) in both normal and diabetic mice and demonstrated its advantages over currently available methods in a clinically-relevant animal model. This concept could serve as a basis for engineering and repairing other tissues in animals.

Viscous Fingering as a Rapid 3D Pattering Technique for Engineering Cell-Laden Vascular-Like Constructs

Tissues are much larger than the diffusion limit distance, so rapidly providing blood vessels to supply embedded cells inside tissues with sufficient nutrients and oxygen is regarded as a major strategy for the success of bioengineered large and thick tissue constructs. Here, a patterning technique, viscous fingering, is developed to bioengineer vascularized-like tissues within a few minutes. By controlling viscosity, flow rate, and the volume of photo-cross-linkable prepolymer, macro- and microscale vascular network structures can be precisely engineered using the Hele-Shaw cell that is designed in this study. After cross-linking, a vascular-like gel with fingering structures is formed between the bottom and top base gels, creating a sandwich-like structure. Cells can be incorporated into the fingers, bases, or both gels. The spreading and growth direction of the embedded cells are successfully controlled and guided by manipulating the physical properties of the fingering and base gels individually. Moreover, fingering is generated, connected, and surrounded prepared cell-laden microgels in base prepolymers to form prevascularized tissue-like constructs. Taken together, the 3D cell patterning technique extends the potential for modeling and fabricating large and stackable vascularized tissue-like constructs for both ex vivo and in vivo applications.

Dynamically and Spatially Controllable Albumin-Based Hydrogels for the Prevention of Postoperative Adhesion

Since the degree of severity and the geometry of wounds vary, it is necessary to prepare an antiadhesive hydrogel that possesses dynamically controllable material properties, exhibits biodegradability, and possesses drug-releasing properties. Injectable, oxygen peroxide-sensitive, and photo-cross-linkable hydrogels that permit in situ dynamic and spatial control of their physicochemical properties were synthesized for the prevention of postoperative adhesion. Albumin is the most abundant protein in blood serum and serves as a carrier for several molecules that exhibit poor water solubility. It is therefore a suitable biomaterial for the fabrication of hydrogels since it presents a low risk of life-threatening complications and does not require immunosuppressive therapy for preventing graft rejection. The physicochemical properties of this hydrogel can then be spatially postadjusted via transdermal exposure to light to release drugs, depending on what is required for the injury. A significant reduction in postoperative peritoneal adhesion was observed in an animal model involving severe sidewall and bowel abrasions. This study demonstrated that the fabricated dually cross-linked, albumin-based hydrogels have great potential in such applications because they showed a low immune response, easy handling, full wound coverage, and tunable biodegradability. Precise spatial and controllable drug-release profiles may also be achieved via in situ transdermal post-tuning of the biomaterials, depending on the injury.

Two-Stage Patterned Cell-Based Treatments for Skin Regeneration

During the process of wound healing, avoiding the formation of aligned collagen fibrils and subsequent scarring has become the focus of numerous research efforts. However, the goal of regeneration of native or scar-free skin remains a challenge. The complex and equivocal connection between inflammation and regeneration within the process of healing contributes to unsatisfactory treatment outcomes. Inspired by the scarless repair observed in fetal wound healing, we create a two-stage treatment combining the hydrocolloid dressing to attenuate the immune response in the initial three days, and the biomimetic cell-laden hydrogel to improve skin regeneration, which meet the specific needs of each stage in the healing process. To further accelerate the skin regeneration, the patterned cell-laden hydrogels were fabricated by photo-mask based photolithography technique. The efficacy and possible mechanisms of skin regeneration using this patterned cell-laden hydrogel therapy was investigated. Results show that these two-stage patterned cell-laden treatments were able to promote vascular network formation, accelerate wound closure, decrease scar formation, increase tissue regeneration and restore structure and mechanical properties of the skin in a full-thickness murine wound model. These data suggest that our patterned cell-based two-stage treatments can be used as a promising therapeutic option for wound healing by accelerating skin tissue regeneration.

[The role and mechanism of regulatory T cells in indirect acute lung injury]

Objective: To study the role and mechanism of CD(4)(+) CD(25)(+) FoxP3(+) regulatory T cells (Tregs) in the pathophysiological process of indirect acute lung injury (iALI) in mice. Methods: The iALI model was successfully induced by shock/cecal ligation and puncture method. Sham (n=8), cecal ligation and puncture (CLP, n=10), and hemorrhage (Hem, n=12) groups were established as controls. Two experimental groups were established: CLP+Hem (n=15) without Tregs adoptive transfer (AT), and CLP+Hem with Tregs adoptive transfer (CLP+Hem+AT, n=14). The number of Tregs, subsets of lymphocytes, neutrophil activity, apoptosis, cytokine levels and histopathological changes were measured in the lung tissue of each group. The protein exudation and the expression of IL-10 in bronchoalveolar lavage fluid (BALF) were also detected. After in vitro cell co-culture, the proliferation of activated T cells and the expression of IL-10, INF-γ and iNOS protein were detected. Results: The percentage and the absolute cell number of CD(4)(+) CD(25)(+) FoxP3(+) Tregs in lung tissue of iALI mice were (2.530±0.086)%, and (1.441±0.090)×10(4)/ml, respectively, which were significantly higher than the control groups (P<0.05). Adoptive transfer of Tregs could significantly decrease CD3-positive T lymphocytes, myeloperoxidase (MPO) activity, caspase-3 activity in lung tissue as well as protein leakage in BALF (P<0.05). Meanwhile interleukin-10 (IL-10) levels in lung tissue and BALF were up-regulated from (121.4±43.76) pg/ml to (201.0±61.96) pg/ml (t=2.776, P<0.05) and (206.2±90.88) pg/ml to (339.4±109.5) pg/ml (t=2.477, P<0.05), respectively. Histopathology was also significantly improved. The proliferation of activated T lymphocytes in the adoptive transfer Treg (AT-Treg) group (n=5) was significantly lower than that in the natural regulatory T cell (N-Treg) group (n=5, t=7.485, P<0.01) and the negative control group (n=5, t=16.66, P<0.01). However, iNOS enzyme inhibitor L-NMMA could significantly reduce the T cell proliferation (P<0.05). Conclusion: CD(4)(+)CD(25)(+)FoxP3(+) Tregs could reduce inflammatory reaction in mice with iALI, and the iNOS signaling pathway may be involved in this process.

Somatometric measurements, and clinical chemistry and hematology parameters in Tibetan macaque (Macaca thibetana)

BACKGROUND

Limited physiological data for Tibetan macaques are available at present. This study will provide more rationale for evaluating this species.

METHODS

Thirty-seven Tibetan macaques (15 males and 22 females) were used in this study. Somatometric measurements, clinical chemistry and hematology parameters, insulin, and C-peptide were analyzed.

RESULTS

Females had higher values of waist and waist hip ratio (WHR) than males in somatometric measurements. There were no significant differences between the two genders in hematology. Significant differences between males and females were only found for aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in biochemistry testing. In addition, females had higher fasting insulin and C-peptide than males. There was a strongly positive correlation between age and some somatometric parameters.

CONCLUSIONS

These physiological data will provide veterinarians and researchers with baseline values to evaluate experimental results using Tibetan macaques.

Thigh muscle volume predicted by anthropometric measurements and correlated with physical function in the older adults

OBJECTIVES

(1) to correlate thigh muscle volume measured by magnetic resonance image (MRI) with anthropometric measurements and physical function in elderly subjects; (2) to predict MRI-measured thigh muscle volume using anthropometric measurements and physical functional status in elderly subjects.

DESIGN

Cross-sectional, nonrandomized study.

SETTING

Outpatient clinic in Taiwan.

PARTICIPANTS

Sixty-nine elderly subjects (33 men and 36 women) aged 65 and older.

MEASURMENTS

The anthropometric data (including body height, body weight, waist size, and thigh circumference), physical activity and function (including grip strength, bilateral quadriceps muscle power, the up and go test, chair rise, and five meters walk time) and bioelectrical impedance analysis data (including total body fat mass, fat-free mass, and predictive muscle size) were measured. MRI-measured muscle volume of both thighs was used as the reference standard.

RESULTS

The MRI-measured thigh volume was positively correlated with all anthropometric data, quadriceps muscle power and the up and go test as well as fat-free mass and predictive muscle mass, whereas it was negatively associated with age and walk time. In predicting thigh muscle volume, the variables of age, gender, body weight, and thigh circumference were significant predictors in the linear regression model: Muscle volume (cm3) =4226.3－42.5 × Age (year)－955.7 × gender (male=1, female=2) + 45.9 × body weight(kg) + 60.0 × thigh circumference (cm) (r2 = 0.745, P < 0.001; standard error of the estimate = 581.6 cm3).

CONCLUSION

The current work provides evidence of a strong relationship between thigh muscle volume and physical function in the elderly. We also developed a prediction equation model using anthropometric measurements. This model is a simple and noninvasive method for everyday clinical practice and follow-up.

External beam radiation therapy for inoperable hepatocellular carcinoma with portal vein thrombosis

Portal vein thrombosis (PVT) in patients with hepatocellular carcinoma (HCC) has a poor impact on prognosis. Many of these tumors may cause intrahepatic and extrahepatic metastases. From January 1991 to December 1996, 41 unresectable HCC patients with PVT underwent transcatheter arterial chemoembolization (TACE) and external beam radiation therapy (EBRT) to the portion of PVT. The irradiated field, with a mean equivalent field size of 6.6 x 7.1 cm2, was localized and simulated by abdominal sonography, angiography and computed tomography. Radiation dose ranged from 36 to 66 Gy (mean dose: 51.4 Gy), in a daily fraction of 1.8 to 2 Gy. The response of EBRT was evaluated by abdominal sonography within 3 months of completion of EBRT. The response rates of the PVT after treatment were 39% for complete response (CR), 41% for partial response (PR), and 19% for no response (NR), respectively. The median overall survival time from start of radiotherapy was 10 months for all patients, 17 months for CR patients, 8 months for PR patients and 4 months for NR patients. By multivariate analysis, response of PVT resulted in a significant improvement in survival. (P = 0.001) There was no occurrence of severe complication of radiation-induced liver disease. The results obtained with combined treatment modality of EBRT and TACE in the treatment of HCC patients with PVT are encouraging.

Red blood cell osmotic fragility in chronically hemodialyzed patients

Chronic renal failure induces anemia and a short erythrocyte life span. Red blood cell (RBC) osmotic fragility is the resistance of RBC hemolysis to osmotic changes that is used to evaluate RBC friability. To find the cause of shortened red cell survival in uremic patients, we evaluated the RBC osmotic fragility in 57 chronic hemodialyzed patients. Each patient had received 12 h of dialysis per week continuously prior to being enrolled in the study. Nineteen healthy volunteers served as a control group. Biochemistry, hemoglobin, electrolyte, osmolarity, beta2-microglobulin, and intact parathyroid hormone were examined before and after the dialysis session. To evaluate the osmotic fragility of RBC, blood samples were collected in heparinized test tubes. Fifty microliters of the RBC of each individual was then incubated in solutions containing a series of various concentrations of NaCl ranging from 0 to 0.6%. The concentration of NaCl at which 50% of RBCs were lysed was considered the median osmotic fragility (MOF). The results showed that the MOF was significantly greater in hemodialyzed patients before dialysis than in the control group (0.41 +/- 0.03 vs. 0.39 +/- 0.02%). The osmotic resistance to hemolysis was also recorded after dialysis (MOF 0.38 +/- 0.03%). Correlation analysis showed that the MOF was significantly correlated with urea nitrogen, serum osmolarity, and intact parathyroid hormone level. In addition, the osmotic fragility was higher in patients who had a predialysis intact parathyroid hormone level > 100 pg/dl. In conclusion, hemodialysis can improve the osmotic fragility. The mechanism underlying this improvement may be the removal of low molecular weight uremic toxins, resulting in normalization of serum osmolarity. Our results indicate that parathyroid hormone is probably a major factor influencing RBC osmotic fragility in chronic renal failure.

Talo-navicular arthrodesis for residual midfoot deformities of a previously corrected clubfoot

Triangular navicular, dorsal-lateral subluxation of the talo-navicular (TN) joint with a secondary forefoot cavovarus deformity, and degenerative changes of the TN joint are frequent causes of residual clubfoot deformity and pain in the midfoot after surgical correction. This study investigates the usefulness of TN arthrodesis to correct these deformities and to resolve symptoms resulting from these deformities. During the period from 1991-1996, the senior author performed 19 TN fusions (16 patients) for the above residual clubfoot deformities involving a painful TN joint. Eight of the procedures (seven patients) also required a lateral column shortening with a calcaneal wedge osteotomy to allow for a complete correction of the TN joint. The procedure was only performed in cases involving a hindfoot that was adequately aligned during a previous clubfoot correction. The average age of the patients at the time of surgery was 11 years (range: 4-20). One patient (bilateral procedures) was lost to follow-up. Fifteen patients (17 procedures) were followed-up for an average of four years (range: 2-6). All patients reported symptomatic improvement after the TN arthrodesis. Fourteen of the patients (15 procedures) were completely satisfied. The remaining patient (bilateral procedures) was only partially satisfied due to the subsequent development of navicular-cuneiform osteoarthritis in both feet. Two cases (2 patients) developed complications requiring a second procedure for satisfactory results. In addition, the procedure resulted in an improvement of the talus-first metatarsal angle on both antero-posterior and lateral radiographs. TN arthrodesis produced a correction of the residual clubfoot deformities of the midfoot and resulted in satisfactory clinical improvement in all the patients.

Avascular necrosis in children with acute lymphoblastic leukemia

This study describes the prevalence and demographics of avascular necrosis (AVN) in children with acute lymphoblastic leukemia (ALL). With improving survival of ALL patients on modern chemotherapy regimens, an increasing number of children with AVN will be presenting to orthopaedists. From 1991 to 1996, 202 patients were treated for ALL at a major tertiary pediatric cancer referral center. Eight patients (4.0%) subsequently developed AVN at an average of 30.0 months after beginning chemotherapy. A total of 27 documented joints were involved, with an average of 3.4 joints affected per patient diagnosed with AVN. The subset of patients with high-risk ALL who underwent an aggressive chemotherapy protocol was particularly susceptible to developing AVN. Six of 58 high-risk ALL patients (10.3%) developed AVN at an average of 18.5 months. As ALL patients now frequently survive into adulthood, orthopaedists will be increasingly called on to manage AVN affecting multiple joints in children and young adults.

Solution structure and dynamics of G1TE, a nonphosphorylated cyclic peptide inhibitor for the Grb2 SH2 domain

The solution structure and dynamics of G1TE, a nonphosphorylated cyclic peptide inhibitor for the Grb2 SH2 domain, was determined using two-dimensional NMR and simulated annealing methods. G1TE consists of 10 amino acids and a C-terminal Cys cyclized through its side-chain sulfur atom by a thioether linkage to its N terminus. The results indicate that G1TE assumes a circle-like shape in solution in which all the side chains are protruding outside, and none of the residues are involved in intramolecular hydrogen bonding. The average root-mean-square deviations were found to be 0.41 +/- 0.11 A for the backbone heavy atoms C, Calpha, and N, and 1.03 +/- 0.14 A for all heavy atoms in a family of 10 structures. (15)N relaxation measurements indicate that G1TE has rather restricted dynamics in the fast time scale within its backbone. However, residues Tyr3, Val6, and Gly7 may be involved in a possible conformational exchange. The structural comparison between G1TE in solution and the BCR-Abl phosphopeptide bound to Grb2 SH2 domain revealed that G1TE may form a larger circle-like binding surface than the BCR-Abl phosphopeptide in the bound form. Also, the restricted backbone dynamics of G1TE may result in a reduced loss of entropy and can compensate for the absence of a phosphate group at the Tyr3 position. These structural and dynamic properties of G1TE may provide a molecular basis for understanding its interactions with the Grb2 SH2 domain.

Revision total hip arthroplasty in patients with avascular necrosis

This retrospective study compared the results of revision total hip arthroplasty (THA) in patients with avascular necrosis to patients with osteoarthritis. Twenty-two revision THAs (34 components) in 19 patients with avascular necrosis were compared with 35 revision THAs (55 components) in 31 patients with osteoarthritis. All of the procedures were performed by a single surgeon between 1981 and 1994, and all patients had a minimum of 2 years of follow-up. At the time of revision surgery, the average age was 54 years for the avascular necrosis patients and 67 years for the osteoarthritis patients (P=.002). Clinical and radiographic follow-up was performed for an average of 7 years (range: 2-12 years). Six (18%) components in the avascular necrosis group and nine (16%) components in the osteoarthritis group required re-revision for aseptic loosening an average of 7 years after the original revision (range: 2-11 years). Statistical analysis demonstrated no significant difference between the two groups in regard to the incidence of failure, time to failure, Harris Hip Score, and radiographic appearance. Contrary to expectations derived from the literature on primary THA, no difference was found between the outcome and survivorship of revision THA in patients with avascular necrosis and patients with osteoarthritis, despite a significant difference in age.

Nonoperatively treated displaced bimalleolar and trimalleolar fractures: a 20-year follow-up

This study evaluates the long-term results of displaced bi- and trimalleolar fractures treated closed. Few reports exist in the literature regarding the long-term outcomes of ankle fractures, and none of these specifically addresses displaced bi- and trimalleolar fractures treated nonoperatively. This study analyzed the results of bi- and trimalleolar fractures treated by a single surgeon from 1973 to 1981. As was the standard of care at that time, these fractures were treated nonoperatively if a stable reduction was achieved and maintained. Serial radiographs confirmed the maintenance of reduction in a non-weightbearing long leg cast for 6 weeks and then a short leg walking cast for 6 weeks. Of the 34 patients in this series, 19 were available for review, 10 were deceased, and five were lost to follow-up. The average age at the time of injury was 39 years (range, 17-79 years), and the average length of follow-up was 20 years (range, 16-24 years). At the time of review, only two patients with trimalleolar fractures were minimally symptomatic or had radiographic evidence of mild degenerative changes. The average American Orthopaedic Foot and Ankle Score was 98 of 100 points (range, 87-100 points). This long-term follow-up shows that bi- and trimalleolar fractures can be treated nonoperatively if an anatomic reduction is maintained and closely followed. With reports indicating as much as a 5% deep infection rate and a 10% incidence of loss of reduction after internal fixation, universally recommending an operation for these injuries should be reconsidered, especially in high surgical risk patients.

Diaphyseal forearm fractures treated with and without bone graft

BACKGROUND

The purpose of this study was to determine whether the acute bone grafting of diaphyseal forearm fractures decreases the incidence of nonunion and reduces the time to union. Although the traditional treatment of comminuted radius and/or ulnar shaft fractures involves bone graft, a recent report called into question this practice.

PATIENTS

A database search was used to identify all acute diaphyseal forearm fractures presenting to an urban Level I trauma center between 1988 and 1996. All radius and/or ulnar shaft fractures, as well as all Monteggia and Galeazzi fracture-dislocations, in patients with closed physes were included. The charts and operative reports were available for 64 diaphyseal forearm fractures in 49 patients. Fifty-six fractures were followed for at least 1 year beyond clinical and radiographic union. The injuries were treated with open reduction and plate fixation by experienced orthopedic traumatologists. All noncomminuted fractures were treated without bone graft. For the comminuted fractures, the decision to use bone graft was left to the discretion of the operating surgeon.

RESULTS

Overall, 55 of 56 fractures (98%) achieved union at a mean of 49 days (range, 19-123 days), with the only nonunion occurring in a patient with a closed, noncomminuted Galeazzi injury. Among the 20 noncomminuted fractures, all of which were treated without bone graft, 19 (95%) achieved union at a mean of 50 days (range, 19-102 days). Among the 36 comminuted fractures, all 25 treated without bone graft achieved fusion at an average of 50 days (range, 20-123 days) and all 11 treated with bone graft achieved union at an average of 45 days (range, 22-67 days). No statistically significant difference in the incidence of nonunion or time to union was noted between fractures that were treated with and without bone graft.

CONCLUSION

Acute bone grafting of diaphyseal forearm fractures did not affect the union rate or the time to union.

Aggressive treatment of 119 open fracture wounds

BACKGROUND

The purpose of this study was to determine whether immediate primary closure of open fracture wounds can be performed without increasing the incidence of infections and delayed unions/nonunions. Although the traditional management of these injuries has been open treatment, a trend toward immediate primary closure has evolved on our service.

METHODS

All open fractures presenting to an urban Level I trauma center during a 42-month period were reviewed. Of the 127 patients with open fractures, 90 patients (119 open fractures) were initially treated at the above institution within 24 hours of injury, had fractures proximal to the carpus or tarsals, and were followed-up until fracture union. All patients underwent emergent wound irrigation and debridement. The method of fracture immobilization and timing of wound closure was left to the discretion of the attending orthopedic surgeon. Immediate primary closure was used in 22 of 25 Grade I open fractures (88%), 37 of 43 Grade II fractures (86%), 24 of 32 Grade IIIa fractures (75%), 4 of 12 Grade IIIb fractures (33%), and 0 of 7 Grade IIIc fractures (0%).

RESULTS

Eight fractures (7%) were complicated by a deep wound infection/osteomyelitis, and 19 fractures (16%) developed a delayed union/nonunion. Statistical analysis revealed no significant difference in delayed/nonunion and infection rates between immediate and delayed closures.

CONCLUSION

Immediate primary closure of open fracture wounds after a thorough debridement by an experienced fracture surgeon appears to cause no significant increase in infections or delayed union/nonunions. In addition, early closure may decrease the requirement for subsequent debridements and soft-tissue procedures, thereby minimizing surgical morbidity, shortening hospital stays, and reducing costs. We feel that a randomized, prospective study of this aggressive approach to open fracture care is warranted.

Relationship between microalbuminuria, left ventricular mass and function in essential hypertension

To investigate the relationship of microalbuminuria, left ventricular hypertrophy and hypertension, 150 hypertensive patients were studied. All patients received a series of blood pressure (BP) measurements, overnight urine collection for microalbuminuria determination, chest radiography (CXR), electrocardiography (EKG) and echocardiographic assessment. Echocardiographic variables including left ventricular mass index (LVMI), fractional shortening (FS) and Doppler mitral flow E/A ratio were analyzed. Patients were divided into 4 groups according to diastolic blood pressure. Left ventricular hypertrophy (LVH) was identified by EKG in 28 patients (18.7%), by CXR in 56 patients (37.3%) and by echocardiography in 126 patients (89.3%). Microalbuminuria was detected in 42 patients (28%). Microalbuminuria tended to present in patients with higher systolic, diastolic and mean blood pressure. There was no relation between FS and E/A ratio and the degree of blood pressure elevation. However, there was a strong correlation between microalbuminuria and LVMI (p < 0.001), this correlation was not related to any difference in blood biochemistry. The results of this study indicate that the severity of microalbuminuria relates closely to the severity of hypertension. In addition, hypertensive patients with microalbuminuria tend to have higher LVMI.

Complete atraumatic rupture of the flexor hallucis longus tendon: a case report and review of the literature

A complete atraumatic rupture of the flexor hallucis longus tendon in a patient without systemic disease is a rare occurrence. Although four cases of complete traumatic ruptures have been cited in the literature, only one case of a complete atraumatic rupture has been previously reported. Presented here is a second case with a review of the literature and a discussion of the surgical indications.

Major causes of diabetic death at one hospital

Death certificates filed between 1987 and 1990 at the Kaohsiung Medical College Hospital (KMCH) were reviewed to investigate causes of diabetic death. During this period, 1,383 patients expired at KMCH, of which 151 had diabetes mellitus. The major causes of death in these 151 diabetic patients were infection in 25.8%, cardiovascular disease in 18.5%, cerebrovascular disease in 11.3%, uremia in 8.6% and diabetic ketoacidosis in 1.3%, while diabetes was reported as the contributory or underlying cause of death. Malignancy in 12.0%, liver disease in 5.3%, trauma in 1.3% and upper gastroenteral bleeding in 0.7%, likewise, were among the leading causes of death irrespective of underlying diabetes. However, cause of death in 15.2% of these diabetic patients was undetermined. Our analysis revealed that infection and cardiocerebrovascular disease were the leading problems contributing to diabetic death. Therefore, reducing the risk of infection by strict glycemic control, intensive medical intervention in infection and the proper prevention of diabetic angiopathy-related risk factors and complications are imperative for the reduction of diabetic mortality in our patients.

Remission of hypoplastic acute leukemia by low dose Ara-C: one case report

The occurrence of hypoplastic acute leukemia is widely recognized as an atypical leukemia, and is defined as hypocellular marrow with more than 30% blasts and none or few blasts in the circulating blood. The pathogenesis of hypoplastic acute leukemia is still unknown. Clinically, it usually follows a less progressive course and has a high prevalence rate among the elderly. The treatment and prognosis remains unclear. We present a case of hypoplastic acute leukemia, which responded well to low dose Ara-C. The 67 year-old female patient had symptoms of bruising easily and dizziness for about 3 years. Initial investigation revealed pancytopenia in the circulating blood and hypocellularity (10%) with blast cells (60%) in the bone marrow. Besides supportive treatment with blood transfusions and antibiotics, chemotherapy of low dose Ara-C 10 mg/m2 was administrated for 14 days by subcutaneous injection. Bone marrow examination revealed an increase of cellularity and a decrease of blast cells following chemotherapy. Anemia and thrombocytopenia also simultaneously improved. Such results may suggest induction of differentiation effect of low dose Ara-C in hypoplastic leukemia.