Adherent bacterial colonization in the pathogenesis of osteomyelitis.

Direct scanning electron microscopy of material obtained during surgical debridement of osteomyelitic bone showed that the infecting bacteria grew in coherent microcolonies in an adherent biofilm so extensive it often obscured the infected bone surfaces. Transmission electron microscopy showed this biofilm to have a fibrous matrix, to contain some host cells, and to contain many bacteria around which matrix fibers were often concentrated. Many bacterial morphotypes were present in these biofilms, and each bacterium was surrounded by exopolysaccharide polymers, which are known to mediate formation of microcolonies and adhesion of bacteria to surfaces in natural ecosystems and in infections related biomaterials. The adherent mode of growth may reduce the susceptibility of these organisms to host clearance mechanisms and antibiotic therapy and thus may be a fundamental factor in acute and chronic osteomyelitis.

Adhesive colonization of biomaterials and antibiotic resistance.

This study addresses the problem of antibiotic resistance in adhesive, biomaterial-centred infections. It is suggested that this anionic, extracapsular, polysaccharide slime produced by bacteria protects them from antibiotics and sequesters critical ions from the surface of biomaterials. Biofilm-enclosed bacteria on the surface of stainless steel substrata in a test chamber were challenged with incremental levels of tobramycin. In this setting, the minimum inhibitory concentration and minimum bactericidal level of tobramycin for Staphylococcus epidermis were well above normal.

Bacterial colonization of percutaneous sutures.

The direct electron microscopic examination of 15 sutures and 15 staples removed from 10 healed surgical wounds showed, on the intradermal portions, consistent colonization by bacteria growing in adherent biofilms. This clearly demonstrable bacterial colonization of biomaterials within the wound tract had not resulted in infection or perceptible inflammation in any of the wounds. These bacterial cells were of several morphotypes, including gram-positive cocci, and all specimens yielded cultures of the autochthonous (native) skin bacterium, Staphylococcus epidermidis. The bacteria within the wound tracts were enveloped by extracellular material that appeared on scanning electron microscopy to be a condensed amorphous residue and on transmission electron microscopy to be a fibrous extracellular matrix. We suggest that this mode of growth, in which the colonizing bacteria are enveloped in a copious exopolysaccharide glycocalix, protects the bacteria from host defense factors and accounts for their persistence on the suture surfaces until they are removed with the sutures.

Bioimplant surfaces: binding of fibronectin and fibroblast adhesion.

The adhesion of baby hamster kidney 21C/13 fibroblasts to surfaces of passivated titanium, carbon fibers, bioactive glasses B5 and B6, fibronectin-precoated passivated titanium, and fibronectin-precoated B6 was quantified. The order of adhesive cell avidity for the uncoated surfaces was passivated titanium (greatest), B6 and carbon fibers (intermediate), and B5 (least). Precoating with fibronectin enhanced the adhesive characteristics of fibroblasts on passivated titanium and B6 by 74% and 118%, respectively.

A prospective evaluation of the clinical utility of the lower-extremity injury-severity scores.

BACKGROUND: High-energy trauma to the lower extremity presents challenges with regard to reconstruction and rehabilitation. Failed efforts at limb salvage are associated with increased patient mortality and high hospital costs. Lower-extremity injury-severity scoring systems were developed to assist the surgical team with the initial decision to amputate or salvage a limb. The purpose of the present study was to prospectively evaluate the clinical utility of five lower-extremity injury-severity scoring systems. METHODS: Five hundred and fifty-six high-energy lower-extremity injuries were prospectively evaluated with use of five injury-severity scoring systems for lower-extremity trauma designed to assist in the decision-making process for the care of patients with such injuries. Four hundred and seven limbs remained in the salvage pathway six months after the injury. The sensitivity, specificity, and area under the receiver operating characteristic curve were calculated for the Mangled Extremity Severity Score (MESS); the Limb Salvage Index (LSI); the Predictive Salvage Index (PSI); the Nerve Injury, Ischemia, Soft-Tissue Injury, Skeletal Injury, Shock, and Age of Patient Score (NISSSA); and the Hannover Fracture Scale-97 (HFS-97) for ischemic and nonischemic limbs. The scores were analyzed in two ways: including and excluding limbs that required immediate amputation. RESULTS: The analysis did not validate the clinical utility of any of the lower-extremity injury-severity scores. The high specificity of the scores in all of the patient subgroups did confirm that low scores could be used to predict limb-salvage potential. The converse, however, was not true. The low sensitivity of the indices failed to support the validity of the scores as predictors of amputation. CONCLUSIONS: Lower-extremity injury-severity scores at or above the amputation threshold should be cautiously used by a surgeon who must decide the fate of a lower extremity with a high-energy injury.

Musculoskeletal injuries in theatrical dance students.

Three hundred and fifty-two injuries in 185 theatrical dance students at the North Carolina School of the Arts were diagnosed and treated from September 1981 through May 1982, the most recent academic year. The total number of dancers enrolled in the school was 218; thus, 84.9% of the dance students were evaluated for an injury by a physician, with 87.8% of the injuries sustained during dance. Approximately one-fourth of the dance-related injuries involved the foot or ankle. The injuries were usually not severe, and proved amenable to treatment by conservative measures.

Total shoulder replacement.

In total shoulder replacement the result is highly dependent upon the integrity or reconstructability of the muscles, tendons, and capsule, as well as the experience of the surgeon. Stability and function of an unconstrained implant are a result of the interrelationship of critical factors such as humeral length, humeral and glenoid version, appropriate abductor tension, rotator cuff integrity, and capsular reconstruction. If these factors are not present and preserved, they must be reconstructed. The results obtained in this study are comparable to those previously published using similar shoulder arthroplasty systems. Total shoulder replacement must be considered a relatively new procedure, but results justify some optimism for the durability of this procedure.

Ultrasonography of the shoulder. Static and dynamic imaging.

High-resolution, real-time ultrasonography is an effective diagnostic technique for evaluating rotator cuff movements and is useful in detecting aberrations that correlate with rotator cuff biomechanics and impingement syndrome.

The use of vacuum-assisted closure therapy for the treatment of lower-extremity wounds with exposed bone.

Lower-extremity wounds with exposed tendon, bone, or orthopedic hardware present a difficult treatment challenge. In this series of patients, subatmospheric pressure therapy was applied to such lower-extremity wounds. Seventy-five patients with lower-extremity wounds, most of which were the result of trauma, were selected for this study. Dressings made of sterile open-cell foam with embedded fenestrated tubing were contoured to the wound size and placed into the wound. The site was covered with an adhesive plastic sheet. The sheet was placed beneath any external fixation devices, or the fixation device was enclosed within the sheet. The tubing was connected to the vacuum-assisted closure pump. Continuous subatmospheric suction pressure (125 mmHg) was applied to the wound site. The wounds were inspected and the dressings were changed every 48 hours.Vacuum-assisted closure therapy greatly reduced the amount of tissue edema, diminishing the circumference of the extremity and thus decreasing the surface area of the wound. Profuse granulation tissue formed rapidly, covering bone and hardware. The wounds were closed primarily and covered with split-thickness skin grafts, or a regional flap was rotated into the granulating bed to fill the defect. Successful coverage was obtained without complication in 71 of 75 patients. Wounds have been stable from 6 months up to 6 years.

Inability to deploy the distal fixator fin of a Brooker-Wills nail.

While a Brooker-Wills nail was being placed in an osteotomized femur during the course of a closed femoral shortening procedure, the slot holding the distal fixator fin was deformed as it was driven across the fracture/osteotomy site (approximately 50% apposition), and the fin could not have been deployed had it been needed for stabilization of the fracture. This case illustrates the importance of maintaining a meticulous closed reduction and of obtaining oblique image intensifier views of the distal portion of this nail while it is being inserted.

Unstable femoral shaft fractures: a comparison of interlocking nailing versus traction and casting methods.

Among 60 femur fractures not amenable to fixation by simple intramedullary nailing, 30 were treated with balanced skeletal traction followed by cast bracing or spica casting, and 30 were treated with closed interlocking nailing. The criteria for using an interlocking nail were fractures with less than 50% cortical contact or fractures with rotationally insecure purchase of the nail in either the proximal or distal fragment. In terms of fracture severity, patient age, injury severity, and clinical follow-up, the patient groups were similar. There were three open fractures in each group. The average hospital stay was 61 days for the traction group, and 19 days for the interlocking nail group (p less than 0.001). Time to clinical and radiographic union averaged 34 weeks with traction and casting and 18 weeks with interlocking nail fixation (p less than 0.001). Failure by the criteria of Johnson et al (2) occurred in 67% of the traction group and in 3% of the interlocking nail group (p less than 0.001). Minor complications were more common in the traction group. On the basis of this study and the experience of others, interlocking nail fixation appears to be the method of choice for managing unstable femoral shaft fractures.

Antibiotic resistance in staphylococci adherent to cortical bone.

The surface-adherent mode of bacterial growth has been shown to play a pivotal role in the persistent nature of infections involving retained foreign bodies, biomaterials, or dead bone (e.g., osteomyelitis). The hypothesis tested herein is that bone and implant materials--polytetrafluoroethylene (PTFE), and polymethylmethacrylate (PMMA)--provide a surface environment that promotes a type of bacterial growth characterized by an enhanced antibiotic resistance. The antibiotic resistance estimates of three staphylococcal subtypes were determined for organisms grown in an adherent state on the aforementioned surfaces as well as in their nonadherent or suspended state. Antibiotic resistance was found to vary with mode of bacterial growth. Secondly, for the staphylococcal subtypes, antibiotics and modes of growth studied herein, adherent growth on bone was associated with the most antibiotic resistance.

Greenfield filter prophylaxis of pulmonary embolism in patients undergoing surgery for acetabular fracture.

Pulmonary embolism is a potentially lethal complication among patients with acetabular fractures requiring surgery. The reliability, safety, and extent of efficacy of pharmacologic as well as existing nonpharmacologic anticoagulation prophylaxis in this patient group has not been determined. A careful analysis of the myriad factors acting on these patients who have had major trauma and have undergone a major surgical procedure about the hip prompted a change in our approach to prophylaxis in this patient group. In the period from March 1984 through October 1987, 51 patients having 52 acetabular fractures underwent osteosynthesis at the Wake Forest University Medical Center. Twenty-four patients had two or more identifiable risk factors and underwent insertion of a Greenfield filter for prevention of pulmonary emboli. Filters were inserted at the time of acetabular surgery with C-arm guidance via the internal jugular vein approach. The average time for insertion was 57 min. Placements were verified by plain roentgenograms. There were no complications during filter insertion. Four patients with filters (17%) developed leg edema; in three the edema was minor, and in one the filter trapped what could have been a fatal embolus but caused lower extremity venous stasis severe enough to result in peripheral lower extremity tissue loss. There were no pulmonary emboli (by clinical criteria). The remaining 27 patients had routine medical prophylaxis and no filters. In this group, two patients had a clinically evident pulmonary embolus (7%), and one of these patients died. Two other patients (7%) had minor chronic leg edema. In one of them, a proximal deep venous thrombosis in the lower extremity was documented with venography, requiring rehospitalization and anticoagulant therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Results in patients with craniocerebral trauma and an operatively managed acetabular fracture.

Results in 23 patients with significant craniocerebral trauma (Glasgow Coma Scale less than or equal to 10) and displaced acetabular fracture requiring surgery were reviewed after a minimum follow-up of 1 year. Despite a postoperative anatomic reduction in all but one case, clinical outcome for these hips was poor, with an average Harris hip rating of 59. Patients older than 40 years had a significantly poorer outcome than did younger patients (p = 0.004). Postoperative problems occurred in 70% of patients (n = 16); the largest portion of these represented symptomatic heterotopic bone, which occurred in 61%. None of the four patients who had an anterior ilioinguinal surgical approach had symptomatic heterotopic ossification. The average Glasgow outcome score was 3.9 out of 5, and 20 of the 23 patients, despite a prolonged convalescence, were able to return to independence and self-care. The authors conclude that patients with combined significant craniocerebral trauma and an operatively managed displaced acetabular fracture are likely to have compromised hip function despite a well-executed osteosynthesis. This was especially true for those patients over age 40 in this series. The authors suggest that if the fracture pattern permits it, the operative management of the acetabular fracture in these patients be by an anterior ilioinguinal approach, so as to minimize the formation of heterotopic bone.

Electromyography monitoring for percutaneous placement of iliosacral screws.

OBJECTIVE: To report our experience with the use of continuous electromyography (EMG) for placement of iliosacral screws. DATA SOURCES: Concurrently acquired data as well as patient charts, intraoperative EMG records, x-rays, and pelvic computed tomography (CT) scans. DESIGN: The monitored group of twenty-nine patients was studied prospectively. The control group consisted of twenty-two patients studied retrospectively. SETTING: Level One trauma center. METHODS: Continuous electromyograms were recorded for twenty-nine patients and compared with those from a group of twenty-two antecedent patients who were not monitored. The primary parameter of interest of this study was the presence or absence of neurologic change after iliosacral screw placement. This information was obtained prospectively in the study group and by retrospective review in the historical control. RESULTS: Four patients in the control group had postoperative and/or sensory motor changes prompting a postoperative CT scan; in each of these patients, a misdirected screw was identified and subsequently removed in a second procedure. There were no neurologic changes subsequent to placement in the twenty-nine patients who were monitored (7.5 percent versus 0 percent; p = 0.029, Fisher's exact test). All monitored patients had postoperative CT scans and showed the screw in a safe position with no significant violations of the S1 tunnel. CONCLUSION: Continuous EMG monitoring during iliosacral screw placement may be a useful neuroprotective tool.

Characterization of patients with high-energy lower extremity trauma.

PURPOSE: (a) to report the demographic, socioeconomic, behavioral, social, and vocational characteristics of patients enrolled in a study to examine outcomes after high-energy lower extremity trauma (HELET) and to compare them with the general population; (b) to determine whether characteristics of patients undergoing limb salvage versus amputation after HELET are significantly different from each other. DESIGN AND STUDY POPULATION: A prospective study of 601 patients admitted with high-energy lower extremity trauma to eight Level I trauma centers. PROCEDURES: Patients were evaluated during the initial hospitalization. They are being followed up for 24 months postinjury. Study patients are compared with the general population by using census information, population survey data, and published norms. Characteristics of patients undergoing limb salvage versus amputation are also compared. RESULTS: Most patients were male (77 percent), white (72 percent), and between the ages of twenty and forty-five years (71 percent). Seventy percent graduated from high school (compared with 86 percent nationally) (p < 0.05). One fourth lived in households with incomes below the federal poverty line, compared with 16 percent nationally (p < 0.05). The percentage with no health insurance (38 percent) was also higher than in the general population (20 percent) (p < .05). The percentage of heavy drinkers was over two times higher than reported nationally (p < 0.01). Study patients were slightly more neurotic and extroverted and less open to new experiences. When patient characteristics were compared for those undergoing amputation versus limb salvage, no significant differences were found among any of the variables (p > 0.05). CONCLUSION: In conclusion, LEAP patients differ in important ways from the general population. However, the decision to amputate verus reconstruct does not appear to be significantly influenced by patient characteristics.

Exertional compartment syndrome in a Marine grunt.

Exercise-induced exertional compartment syndrome was first described by Vogt in 1945 as "march gangrene." The authors report a case of a 20-year-old United States Marine presenting with the florid findings of acute crural compartment syndrome. The patient's history of prior episodes of crural pain following long hikes led the authors to conclude that this patient had a chronic exertional compartment syndrome.

Disruption of the posterior pelvic ring caused by vertical shear.

Disruption of the posterior pelvic ring caused by vertical shearing forces is associated with significant morbidity and mortality. We reviewed the intermediate results in 18 patients who had 20 disruptions of the posterior pelvic ring. Depending on the location of the injury, patients were treated by either skeletal traction or open reduction and internal fixation. Patients who had open reduction and internal fixation had a significantly shorter hospitalization, a shorter confinement to bed, a shorter time to full weight-bearing, and fewer early complications. In addition, on intermediate follow-up, these patients had less back and leg pain and fewer gait disturbances, and were more likely to be able to do heavy work. Further study is needed to determine whether these results will be preserved on long-term follow-up.