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Biomedical subjects

R R Richards

Publications and source records attributed to R R Richards.

At least 19 recordsLinked to original sources
PubMed2003

Osteoblastoma of the clavicle.

A 14-year-old female with a 1-year history of a painful clavicle mass underwent resection and reconstruction with an intercalated autograft and rigid plate fixation. The histopathology was diagnostic for osteoblastoma. Although a clavicle mass is a common entity following clavicle trauma, less common disorders such as bone tumors need to be considered in the differential diagnosis. Osteoblastoma is an uncommon, benign bone tumor representing 1% of all primary bone tumors. An extensive review of the literature reveals only one reported case of clavicular osteoblastoma.

Adolescent↗
PubMed2000

Functional outcome following surgical treatment of intra-articular distal humeral fractures through a posterior approach.

BACKGROUND: While surgical repair is considered the standard of care of displaced intra-articular distal humeral fractures, most investigators have assessed its results with use of surgeon-based and/or radiograph-based outcome measures. The purpose of our study was to determine the functional outcome of fixation of displaced intra-articular distal humeral fractures with use of a standardized evaluation methodology consisting of objective testing of muscle strength and use of patient-based questionnaires (both limb-specific and general health-status questionnaires). METHODS: We identified twenty-five patients (fourteen male and eleven female), with a mean age of forty-seven years, who had an isolated, closed, displaced, intercondylar, intra-articular fracture of the distal part of the humerus repaired operatively through a posterior approach and fixed with plates on both the medial and the lateral column. All patients returned for follow-up that included recording of a complete history, physical examination, radiographic examination, completion of both a limb-specific questionnaire (Disabilities of the Arm, Shoulder and Hand [DASH]) and a general health-status questionnaire (Short Form-36 [SF-36]), and objective muscle-strength testing. RESULTS: The mean duration of follow-up was thirty-seven months (range, eighteen to seventy-five months). The mean flexion contracture was 25 degrees (range, 5 to 65 degrees), and the mean arc of flexion-extension was 108 degrees (range, 55 to 140 degrees). Significant decreases in mean muscle strength compared with that on the normal side were seen in both elbow flexion measured at 90 degrees (74 percent of normal, p = 0.01) and elbow extension measured at 45 degrees (76 percent of normal, p = 0.01), 90 degrees (74 percent of normal, p = 0.01), and 120 degrees (75 percent of normal, p = 0.01). The mean DASH score was 20 points, indicating mild residual impairment. The SF-36 scores revealed minor but significant decreases in the role-physical and physical function scores (p = 0.01 and 0.03, respectively) but no alteration of the mental component or mean scores. Six patients (24 percent) had a reoperation; three of them had removal of prominent hardware used to fix the site of an olecranon osteotomy. CONCLUSIONS: The surgical repair of an intra-articular distal humeral fracture is an effective procedure that reliably maintains general health status as measured by patient-based questionnaires. Our study quantified a decrease in the range of motion and muscle strength of these patients, which may help to explain the mild residual physical impairment detected by the limb-specific outcome measures and physical function components of the general health-status measures.

Adult↗
PubMed1999

Femoral bone blood flow after reaming and intramedullary canal preparation: a canine study using laser Doppler flowmetry.

This study was conducted to determine the effect of intramedullary reaming and canal preparation on bone blood flow in the proximal femur. Thirty-five adult dogs were randomly assigned to have their intramedullary canals prepared after reaming in the following manner: group 1, ream only; group 2, lavage; group 3, methylmethacrylate cement introduction; group 4, cement pressurization after placing a cement restrictor; group 5, lavage then cement introduction; and group 6, lavage then cement pressurization. Bone blood flow was measured at both metaphyseal and diaphyseal sites by using laser Doppler flowmetry before reaming, after reaming, after lavage, after cementing, and at 6 weeks after the procedure just before euthanasia. Reaming significantly decreased bone blood flow in the diaphysis (P = .046) but not in the metaphysis. Cement introduction and cement pressurization both significantly decreased bone blood flow in the metaphysis (P = .035, P = .004) and diaphysis (P = .007, P = .029). Pressurization of cement had a significantly greater relative effect than cement introduction alone in the diaphysis (P = .006) but not in the metaphysis. Lavage had no effect on bone perfusion. Bone blood flow was significantly increased at 6 weeks after the initial procedure in both the metaphysis (P = .049) and the diaphysis (P = .004). The results suggest that reaming decreases diaphyseal cortical but not metaphyseal bone blood flow significantly, whereas lavage has no effect. Cement introduction with or without pressurization has a significant detrimental effect on metaphyseal and diaphyseal blood flow. These findings have implications for intramedullary nailing and for canal preparation when performing arthroplasty.

Animals↗
PubMed1999

Pathophysiological effect of fat embolism in a canine model of pulmonary contusion.

BACKGROUND: The objective of this study was to determine the individual and combined effects of pulmonary contusion and fat embolism on the hemodynamics and pulmonary pathophysiology in a canine model of acute traumatic pulmonary injury. METHODS: After a thoracotomy, twenty-one skeletally mature dogs were randomly assigned to one of three groups. Unilateral pulmonary contusion alone was produced in Group 1 (seven dogs); pulmonary contusion and fat embolism, in Group 2 (seven dogs); and fat embolism alone, in Group 3 (seven dogs). Pulmonary contusion was produced by standardized compression of the left lung with a piezoelectric force transducer. Fat embolism was produced by femoral and tibial reaming followed by pressurization of the intramedullary canals. Cardiac output, systolic blood pressure, peak airway pressure, pulmonary arterial pressure, pulmonary capillary wedge pressure, partial pressure of arterial oxygen, and partial pressure of carbon dioxide were monitored for all groups. From these data, several outcome parameters were calculated: total thoracic compliance, alveolar-arterial oxygen gradient, and ratio of partial pressure of arterial oxygen to fractional inspired oxygen concentration. All of the dogs were killed after eight hours, and tissue samples were obtained from the brain, kidneys, and lungs for histological analysis. Lung samples were assigned scores for pulmonary edema (the presence of fluid in the alveoli) and inflammation (the presence of neutrophils or hyaline membranes, or both). The percentage of the total area occupied by fat was determined. RESULTS: Pulmonary contusion alone caused a significant increase in the alveolar-arterial oxygen gradient but only after seven hours (p = 0.034). Fat embolism alone caused a significant transient decrease in systolic blood pressure (p = 0.001) and a significant transient increase in pulmonary arterial pressure (p = 0.01) and pulmonary capillary wedge pressure (p = 0.015). Fat embolism alone also caused a significant sustained decrease in the ratio of partial pressure of arterial oxygen to fractional inspired oxygen concentration (p = 0.0001) and a significant increase in the alveolar-arterial oxygen gradient (p = 0.0001). The combination of pulmonary contusion and fat embolism caused a significant transient increase in pulmonary capillary wedge pressure (p = 0.0013) as well as a significant sustained decrease in partial pressure of arterial oxygen (p = 0.0001) and a significant decrease in systolic blood pressure (p = 0.001) that lasted for an hour. Pulmonary contusion followed by fat embolism caused a significant increase in peak airway pressure (p = 0.015), alveolar-arterial oxygen gradient (p = 0.0001), and pulmonary arterial pressure (p = 0.01), and these effects persisted for five hours. Total thoracic compliance was decreased 6.4 percent by pulmonary contusion alone, 4.6 percent by fat embolism alone, and 23.5 percent by pulmonary contusion followed by fat embolism. The ratio of partial pressure of arterial oxygen to fractional inspired oxygen concentration was decreased 23.7 percent by pulmonary contusion alone, 52.3 percent by fat embolism alone, and 65.8 percent by pulmonary contusion followed by fat embolism. The mean pulmonary edema score was significantly higher with the combined injury than with either injury alone (p = 0.0001). None of the samples from the lungs demonstrated inflammation. Fat embolism combined with pulmonary contusion resulted in a significantly greater mean percentage of the area occupied by fat in the noncontused right lung than in the contused left lung (p = 0.001); however, no significant difference between the right and left lungs could be detected with fat embolism alone. The mean percentage of the glomerular and cerebral areas occupied by fat was greater with fat embolism combined with pulmonary contusion than with fat embolism alone (p = 0.0001 and p = 0.01, respectively). (ABSTRACT TRUNCATED)

Airway Resistance↗
PubMed1999

Treatment of osteonecrosis of the femoral head by free vascularized fibular grafting: an analysis of surgical outcome and patient health status.

OBJECTIVE: To evaluate the limb-specific outcome and general health status of patients with osteonecrosis of the femoral head treated with vascularized fibular grafting. DESIGN: A retrospective review. SETTING: A single tertiary care centre. PATIENTS: Fifty-five consecutive patients with osteonecrosis of the femoral head who underwent fibular grafting (8 bilaterally). INTERVENTION: Vascularized fibular grafting. OUTCOME MEASURES: Limb-specific scores (Harris Hip Score, St. Michael's Hospital Hip Score), general health status (Nottingham Health Profile, SF-36 health status survey) and radiographic outcome measures (Steinberg stage). RESULTS: Patients were young (mean age 34 years, range from 18 to 52 years) and 80% had advanced osteonecrosis (Steinberg stages IV and V). Fifty-nine hips were followed up for an average of 50 months (range from 24 to 117 months) after vascularized fibular grafting. Sixteen hips (27%) were converted to total hip arthroplasty (THA). To date, 73% of hips treated with vascularized fibular grafting have required no further surgery. Preoperative and postoperative Harris Hip Scores were 57.3 and 83.6 respectively (p < 0.001). As measured by patient-oriented health status questionnaires (SF-36, Nottingham Health Profile) and compared with population controls, patients had normal mental health scores and only slight decreases in physical component scores. CONCLUSIONS: Free vascularized fibular grafting for osteonecrosis of the femoral head provides satisfactory pain relief, functional improvement and general health status and halts the progression of symptomatic disease.

Adolescent↗
PubMed1998

Donor site morbidity following vascularized fibular grafting.

We examined donor site morbidity in thirty-nine patients with avascular necrosis of the femoral head treated by curettage and transplantation of a free ipsilateral fibular graft. Utilising our donor site morbidity questionnaire, scar, functional loss, wound healing, complications, and pain were analysed. Subjective complaints and objective findings were evaluated and compared. Subjective complaints were common and included a sense of instability in 42% and a sense of weakness in 37%. However, objective findings were limited. No clinical instability could be elicited and only great toe flexion (29%) and extension (43%) were found to be mildly weak. Only one patient required reoperation for a donor site problem (2%). Eighty-nine percent were pain free at time of follow-up, and 93% felt the scar was good. Range of motion of the knee and ankle of the donor site leg was not different from the nonoperated leg. Donor site morbidity for avascular necrosis of the femoral head is low.

Adult↗
PubMed1998

A biomechanical assessment of ligaments preventing dorsoradial subluxation of the trapeziometacarpal joint.

Degenerative arthritis of the trapeziometacarpal joint is commonly associated with ligament laxity and joint subluxation. Specifically, key pinch in an affected joint often results in dorsoradial joint subluxation. This study examined the role the 4 ligaments of the trapeziometacarpal joint play in preventing dorsoradial subluxation. Six fresh-frozen cadaver hands were dissected of all soft tissue to expose the joint capsule and ligaments of the trapeziometacarpal joint. Serial random sectioning of the intermetacarpal ligament, anterior oblique ligament, palmar oblique ligament, and dorsoradial collateral ligament (RCL) was performed. Dorsoradial displacement of the metacarpal shaft in relation to the trapezium was measured using a linear variable dimension transformer. In all 6 specimens, sectioning of the RCL resulted in the greatest dorsoradial subluxation of the metacarpal. The mean displacement due to sectioning of the RCL was 1.4 mm, compared with 0.08 mm for the intermetacarpal ligament, 0.06 mm for the anterior oblique ligament, and 0.2 mm for the palmar oblique ligament. The importance of the RCL in preventing dorsoradial subluxation may have clinical significance. This study suggests that repairing or reconstructing the RCL during ligament reconstruction of the trapeziometacarpal joint should be considered.

Biomechanical Phenomena↗
PubMed1998

Femoral and cruciate blood flow after retrograde femoral reaming: a canine study using laser Doppler flowmetry.

OBJECTIVE: To determine the effect of retrograde femoral reaming on the blood flow of the distal femur and the cruciate ligaments. DESIGN: Canine experimental study. SETTING: Tertiary referral and teaching hospital in Toronto, Canada. PARTICIPANTS: Thirteen skeletally mature, cross-bred dogs. MAIN OUTCOME MEASURE: Red cell flux (RCF) was measured by using a laser Doppler flowmetry probe at three bone sites in the distal femur (trochlear groove, medial condyle, and lateral condyle) and at the midportion of both the anterior and posterior cruciate ligaments before and after retrograde femoral reaming. RESULTS: There was a significant increase in the mean postreaming RCF at all the bone sites of the distal femur compared with prereaming values: trochlear groove (p = 0.0247), medial condyle (p = 0.0440), and lateral condyle (p = 0.0042). We also found a significant decrease in the mean postreaming RCF at both cruciate ligament sites compared with prereaming values (anterior cruciate, p = 0.0004; posterior cruciate, p = 0.0006). CONCLUSIONS: Retrograde femoral reaming and intramedullary nailing has become a popular option for the treatment of distal femoral and some femoral shaft fractures, but concerns regarding the effect of reaming through an intraarticular entry portal have been raised. Our experimental study found that after reaming perfusion of the anterior cruciate ligament decreased by 52 percent and perfusion of the posterior cruciate ligament decreased by 49 percent. Diminished perfusion after reaming may delay healing or exacerbate existing injury to the cruciate ligaments and adversely affect rehabilitation of the knee after femoral fracture.

Animals↗
PubMed1998

A biomechanical evaluation of different plates for fixation of canine radial osteotomies.

BACKGROUND AND METHODS: The biomechanical properties of plates depend on their geometries and elastic moduli. The low contact-dynamic compression plate (LC-DCP) with relieved undersurfaces is a modification of the dynamic compression plate (DCP). Little attention has been directed toward comparison of the biomechanical properties of the LC-DCP and the DCP. This study compared the stiffness and strength of bone-plate constructs using plates of various designs and materials for fixation of radial osteotomies. In 20 matched pairs of canine radii, midshaft transverse osteotomies were created and fixed with 3.5-mm eight-hole plates on the volar surface. In 10 pairs, stainless-steel LC-DCPs and stainless-steel DCPs were applied. In the other 10 pairs, stainless-steel LC-DCPs and titanium LC-DCPs were placed. Bending and torsional stiffness were determined. The plates were removed, and a 5-mm gap was created at the osteotomy site. The plates were reapplied to the bones with the interfragmental gap. Stiffness and yield point in the anteroposterior direction were determined. RESULTS: In the absence of a bone gap, no statistically significant differences in construct stiffness were seen between the paired groups. In the presence of a gap, the stainless-steel LC-DCP construct was stiffer than the titanium LC-DCP construct (p = 0.02), and the DCP construct was stiffer than the LC-DCP construct (p = 0.002). The yield point of the DCP-bone construct was 59% greater than that of the stainless-steel LC-DCP construct (p = 0.02). However, the yield points of the titanium and stainless-steel LC-DCP-constructs were similar (p = 0.35). CONCLUSION: The similar results between constructs in the absence of a gap indicate that plate design and material properties may be less significant for achieving adequate stability after plate fixation of simple fractures. The use of the stiffer dynamic compression plate may be advantageous when maximum stability is required, such as with comminution or bone loss.

Animals↗
PubMed1998

Pulmonary and systemic fat embolization after medullary canal pressurization: a hemodynamic and histologic investigation in the dog.

BACKGROUND: The potential to produce fat embolism may be important in determining the ideal method and timing of fracture treatment in patients with preexisting lung injury. METHODS: Four dogs underwent femoral and tibial canal reaming and pressurization. Blood gas samples were analyzed, and pulmonary arterial pressure was monitored at 1 and 72 hours. Animals were killed 72 hours postoperatively, and the lungs, kidneys, and brain were examined histologically and compared with equivalent specimens from four control dogs that had not undergone femoral and tibial canal reaming and pressurization. RESULTS: Postmortem, intravascular fat persisted for 72 hours after induction of pulmonary fat embolism. Mean PaO2 was unchanged from baseline at 72 hours after canal pressurization. Canal pressurization caused a sustained increase in pulmonary arterial pressure (p=0.02) for 1 hour after canal pressurization. The mean pulmonary edema score at 72 hours was 29+/-3. Only a scant polymorph infiltrate (zero to two polymorphs per high-power field) was present at any time. No hyaline membranes were seen at any time. The percentage area occupied by intravascular fat in the lungs was 0.0214+/-0.0058 at 72 hours. No signs of ischemia or inflammation were seen in either the cerebral or the renal specimens. CONCLUSION: This study is the first to show that intravascular fat persists in the lungs, kidneys, and brain for 72 hours after canal pressurization and, by itself, does not cause pathologic evidence of acute inflammation.

Animals↗
PubMed1998

The role of methylmethacrylate monomer in the formation and haemodynamic outcome of pulmonary fat emboli.

We examined the roles of methylmethacrylate (MMA) monomer and cementing technique in the formation, and haemodynamic outcome, of pulmonary fat emboli. The preparation of the femoral canal and the cementing technique were studied in four groups of adult dogs as follows: control (no preparation); lavage; cement pressurisation; and cement pressurisation after lavage. We measured the intramedullary pressure, pulmonary artery pressure (PAP), pulmonary capillary wedge pressure and bilateral femoral vein levels of triglyceride, cholesterol and MMA monomer at rest and after reaming, lavage, and cementing. Femoral vein triglyceride and cholesterol levels did not vary significantly from resting levels despite significant elevations in intramedullary pressure with reaming, lavage and cementing (p = 0.001). PAP was seen to rise significantly with reaming (p = 0.0038), lavage (p = 0.0031), cementing (p = 0.0024) and cementing after lavage (p = 0.0028) while the pulmonary capillary wedge pressure remained unchanged. MMA monomer was detected in femoral vein samples when cement pressurisation was used. Intramedullary lavage before cementing had no significant effect on the MMA level. Haemodynamic evidence of pulmonary embolism was noted with reaming and intramedullary canal preparation, irrespective of the presence of MMA monomer. We found no relationship between MMA monomer level and intramedullary pressure, PAP or pulmonary capillary wedge pressure. Our findings suggest that the presence of MMA monomer in femoral venous blood has no effect on the formation of fat emboli or their pulmonary haemodynamic outcome during cemented hip arthroplasty.

Animals↗
PubMed1998

Validity of observer-based aggregate scoring systems as descriptors of elbow pain, function, and disability.

Current elbow-scoring systems are based on the observer-derived assessment of a variety of clinical and functional criteria, which are scored separately and then aggregated. The aggregate score then is assigned a categorical ranking that ranges from excellent to poor. The developers of different elbow-scoring systems have chosen different outcome criteria, assigned different weights to each criterion, and accorded different ranges of values to each categorical ranking. Five different elbow-scoring systems (the Mayo elbow-performance index and the systems of Broberg and Morrey, Ewald et al., The Hospital for Special Surgery, and Pritchard) were used to evaluate the same group of patients. The validity of the scoring systems was determined with use of visual-analog scales for the assessment of pain and function, patient and physician-derived ratings of the severity of impairment of the elbow, and two functional questionnaires completed by the patient (the Disabilities of the Arm, Shoulder and Hand questionnaire and the Modified American Shoulder and Elbow Surgeons patient self-evaluation form). The study sample consisted of sixty-nine patients who had sought treatment at one of two tertiary referral clinics because of problems related to the elbow. Pearson product-moment correlation coefficients were used to compare the raw aggregate scores, and kappa statistics were used to determine the level of agreement among the categorical rankings (excellent, good, fair, and poor). Examination of the five scoring systems revealed a remarkable lack of concordance with regard to the aspects of elbow function that were assessed. Good correlation was observed when the systems were compared on the basis of raw scores (Pearson product-moment correlation coefficients, 0.79 to 0.90), but only slight-to-moderate correlation was noted when the systems were compared on the basis of categorical rankings (quadratic weighted kappa coefficients, 0.18 to 0.49). Validity testing showed the system of Ewald et al. and the Mayo elbow-performance index to be the most discriminating, the system of Pritchard to be the least discriminating, and the system of The Hospital for Special Surgery and the system of Broberg and Morrey to be intermediate. The scores determined with the elbow-scoring systems demonstrated only moderate correlation with the score for function on the visual analog scale (Pearson product-moment correlation coefficients, 0.44 to 0.66), whereas those derived from the functional questionnaires completed by the patient demonstrated moderate-to-good correlation with the score for function (Pearson product-moment correlation coefficients, 0.72 and 0.80).

Adolescent↗
PubMed1997

The relative importance of intramedullary, intracortical, and extraosseous soft-tissue blood flow to the repair of devascularized canine tibial cortex.

Previous studies have not quantified the relative contributions of intracortical and extracortical perfusion to cortical porosity and new bone formation. The current study was performed to determine the relative importance of intramedullary, intracortical, and extraosseous soft-tissue blood flow and type of tissue to the repair of devascularized canine tibial cortex. A 2.5-cm segment of tibia between two standardized osteotomies was devascularized. The segment was replaced anatomically and stabilized with a plate. The animals were divided randomly into two groups: skin coverage (N = 8) and muscle coverage (N = 8). Thirty-one days postoperatively, cerium141 microspheres were injected, prior to sacrifice, to measure blood flow. Extraosseous soft-tissue perfusion was the same in the skin coverage and muscle flap coverage groups. There was no relationship between intramedullary or extraosseous soft-tissue flow and depth of new bone formation and cortical porosity. Intracortical blood flow was directly related to depth of new bone formation (p = 0.0006) and cortical porosity (outer cortex, p = 0.001; inner cortex, p = 0.0001). These findings indicate that the cortical repair process is linked to the restoration of perfusion and that muscle coverage, rather than the quantity of blood flow, determines the extent of cortical repair.

Animals↗
PubMed1997

Nonunion of distal radial fractures associated with distal ulnar shaft fractures: a report of four cases.

Although complications following distal radial fractures are common, nonunion is rare. We report four cases of radial nonunion following distal radial fractures that occurred in elderly women after low-energy falls. The distinctive feature of these injuries was the presence of an associated distal ulnar shaft fracture. All patients had initial closed reduction and cast immobilization, which was unsuccessful. Reconstruction was complicated by deformity, disuse osteoporosis, radiocarpal stiffness, and distal radioulnar joint disruption. Wrist arthrodesis improved function and decreased pain and deformity in three patients. Metaphyseal distal radial fractures associated with distal ulnar shaft fractures represent an unstable injury pattern, and closed reduction and casting may not be adequate treatment. Once established nonunion is present, wrist arthrodesis is a useful salvage procedure.

Aged↗
PubMed1997

Pulmonary effects of fixation of a fracture with a plate compared with intramedullary nailing. A canine model of fat embolism and fracture fixation.

UNLABELLED: Fat-embolism syndrome and pulmonary dysfunction may develop in multiply injured patients who have a fracture of a long bone. Although early fixation of a fracture is beneficial, intramedullary nailing may exacerbate pulmonary dysfunction by causing additional embolization of marrow fat. We examined the pulmonary effects of the timing and method of fixation of a fracture in a canine fat-embolism model. Fat embolism was induced in forty-one adult dogs by reaming the ipsilateral femur and tibia followed by pressurization of the intramedullary canal. The animals were divided into a control group of eight dogs that had induction of fat embolism alone and an experimental group of thirty-three dogs that had induction of fat embolism and internal fixation of a transverse fracture of the middle of the contralateral femoral shaft. In the control group, four dogs each were killed four hours and twenty-four hours after induction of fat embolism. In the experimental group, a femoral fracture was created and fixation was performed four hours after embolic showering in fifteen animals and twenty-four hours after embolization in eighteen animals. The two experimental groups were subdivided according to the method of fixation of the fracture: eleven dogs each had application of a plate, nailing without reaming, and nailing with reaming. The pulmonary arterial pressure and the alveolar-arterial gradient were measured preoperatively, during induction of fat embolism, and as long as one hour after fixation of the fracture but before the animal was killed. The lungs, brain, and kidneys were examined for pathological and physiological evidence of intravascular fat. The intravascular fat persisted for twenty-four hours after induction of pulmonary fat embolism. Pulmonary arterial pressure remained elevated at four hours after the embolic showering, before creation and fixation of the fracture. By twenty-four hours after the induction of fat embolism, pulmonary arterial pressure had returned to the baseline level. Neither the creation nor the fixation of the fracture affected pulmonary arterial pressure. In the animals that had fixation of a fracture four hours after embolization, both nailing with reaming and nailing without reaming produced alveolar-arterial gradients that were higher than the baseline values, whereas fixation with a plate did not change the alveolar-arterial gradient significantly from the baseline value. In addition, the alveolar-arterial gradients in the animals that had nailing with reaming and nailing without reaming four hours after embolization were, respectively, four and 3.5 times higher than that in the animals that had fixation of the femur with a plate. In the animals that had fixation twenty-four hours after embolization, none of the methods for fixation affected the alveolar-arterial gradient. The amount of embolic fat in the lungs, brain, and kidneys was not affected by fixation of the fracture when it was performed at either the four-hour or the twenty-four-hour time-interval. Scores for pulmonary edema were increased by fixation of the fracture, but there was no difference among the scores associated with the three methods of fixation. CLINICAL RELEVANCE: The findings of the present study indicated that the amount of intravascular fat persisting in the lungs, kidneys, and brain twenty-four hours after pressurization of the intramedullary canal is not affected by the method of fixation of the fracture. Fixation of a fracture is associated with minimum evidence of acute inflammation and has no effect on pulmonary artery pressure. The development of pulmonary dysfunction from fat emboli depends on other factors, not just on the presence of fat in pulmonary vessels. It appears that the method of fracture fixation has little influence on the outcome of treatment.

Animals↗