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Biomedical subjects

Steven A Olson

Publications and source records attributed to Steven A Olson.

At least 19 recordsLinked to original sources
PubMed2006

Comprehensive morphologic evaluation of the hip in patients with symptomatic labral tear.

A torn acetabular labrum is a well-documented source of hip pain, but the mechanism of injury is debated because the relationship between the bone morphology and labral tears is poorly understood. We compared hips with and without labral abnormalities to determine the relative incidence of morphologic abnormalities. The study group consisted of patients with a labral tear confirmed by arthroscopy or arthrotomy at the time of open débridement or periacetabular osteotomy. We compared the affected hip with the contralateral, unaffected hip to ascertain signs of hip dysplasia and impingement. We observed differences in the center edge angle, acetabular depth to width index, acetabular index of elevation, femoral head extrusion, lateral and superior subluxation, Sharp's angle, peak to edge distance, and acetabular retroversion. Similar differences occurred in the subgroup analyses. Symptomatic labral tears correlated with abnormal hip morphology as reflected by radiographic measurements of dysplasia and impingement. This relationship occurred in patients with hip dysplasia and patients without obvious femoral head uncovering. Our findings suggest abnormal hip morphology may be a risk factor for labral tears.

Acetabulum↗
PubMed2006

Validation of a Spanish version of the Short Musculoskeletal Function Assessment Questionnaire (SMFA).

OBJECTIVES: The purpose of this study was to develop a linguistically appropriate, culturally adapted, and appropriately validated Spanish version of the SMFA (SMFA-Mex). DESIGN: Validation of a survey-based outcome instrument. SETTING: Busy state hospital in southern Mexico. PATIENTS/PARTICIPANTS: Consecutive trauma patients with a variety of orthopedic disorders. INTERVENTION: N/A. MAIN OUTCOME MEASUREMENTS: The SMFA-Mex was forward and back translated, administered to orthopedic trauma patients, and compared against the Spanish version of the SF-36s for criterion validity. Statistical analysis included factor analysis, criterion validation with the SF-36, and internal measures of reliability. RESULTS: Factor analysis demonstrated three separate subscale dimensions: 1) upper-extremity dysfunction, 2) lower-extremity dysfunction, and 3) lifestyle alterations. Item analysis showed a high degree of internal consistency for the three subscales (subscale 1, r = 0.95; subscale 2, r = 0.94; subscale 3, r = 0.92). Test-retest reliability at 7 days was 0.93 for the upper-extremity dysfunction subscale, 0.95 for the lower-extremity dysfunction subscale, and 0.92 for the lifestyle-alterations subscale. Construct validity was established by comparison of the Brazilian version of the SF-36. CONCLUSIONS: The SMFA-Mex was successfully translated and culturally adapted from the English original. The SMFA-Mex demonstrated adequate scale reliability and validity and yielded three distinct subscales using factor analysis.

Adolescent↗
PubMed2006

Influence of acetabular coverage on hip survival after free vascularized fibular grafting for femoral head osteonecrosis.

BACKGROUND: Osteonecrosis of the femoral head frequently results in collapse of the head and subsequent arthrosis of the joint. Surgical treatment has been based entirely on the evaluation of the femoral side of the hip joint, with little consideration given to the possible influence on outcome of the orientation of the acetabulum. METHODS: We retrospectively reviewed a consecutive series of 200 hips in 160 patients with osteonecrosis of the femoral head who had undergone free vascularized fibular grafting between 1997 and 1998. The mean duration of clinical follow-up was 7.5 years. Ninety-one hips in seventy-one patients were evaluated radiographically for evidence of progression of femoral head collapse at a minimum of two years, and a mean of three years, postoperatively. We defined conversion to a total hip arthroplasty and progression of femoral head collapse as the failure end points, and we analyzed the association of the acetabular center-edge angle of Wiberg, the area and laterality of the lesion, the amount of preoperative collapse of the femoral head, and the etiology of the osteonecrosis with the likelihood of failure. RESULTS: Forty-eight (24%) of the 200 hips had undergone conversion to a total hip arthroplasty at the time of the final clinical follow-up. In addition, 15% (fourteen) of the ninety-one hips with sufficient radiographic follow-up demonstrated progression of femoral head collapse at the time of the final radiographic examination. Of the hips with a center-edge angle of </=30 degrees , 55% (of those with sufficient radiographic follow-up) demonstrated progressive collapse and 45% were converted to a total hip arthroplasty. In contrast, of the hips with a center-edge angle of >30 degrees , 10% had progressive collapse (p = 0.002) and 6% were converted to a total hip arthroplasty (p < 0.001). Neither the etiology nor the size of the lesion was significantly correlated with progression of collapse or conversion to a total hip arthroplasty. CONCLUSIONS: Patients with osteonecrosis of the femoral head and a suboptimal center-edge angle of the hip are at substantial risk for progression of femoral head collapse and conversion to a total hip arthroplasty following free vascularized fibular grafting. An estimation of the degree of hip dysplasia should be included in the preoperative assessment of patients with osteonecrosis of the femoral head for prognostic and possibly surgical planning purposes.

Acetabulum↗
PubMed2005

Cross-cultural adaptation and validation of the Brazilian Portuguese version of the short musculoskeletal function assessment questionnaire: the SMFA-BR.

BACKGROUND: This study was designed to translate, culturally adapt, and validate a Brazilian Portuguese version of the Short Musculoskeletal Function Assessment Questionnaire (SMFA-BR). METHODS: The SMFA was translated from English into Brazilian Portuguese. Translations were synthesized, translated back into English, and then submitted to a committee of clinical, psychometric, and language experts. The questionnaire was then administered to 220 trauma patients at a midsize hospital in southern Brazil. Test-retest reliability was examined at one and seven days. Scale reliability and validity were assessed, and factor structure was analyzed. RESULTS: Patients with only one region of dysfunction reported less dysfunction than did patients with two or three regions of dysfunction. Both the SMFA-BR dysfunction and the SMFA-BR bother scores had significant correlations with all Brazilian Short Form-36 (SF-36) subscales except for bodily pain. Test-retest reliabilities, as determined by intraclass correlation analyses, were 0.99 (95% confidence interval, 0.97, 1.00) at one day (n = 10) and 0.99 (95% confidence interval, 0.96, 1.00) at seven days (n = 17) for the dysfunction index and 0.99 (95% confidence interval, 0.98, 1.00) at one day (n = 10) and 0.97 (95% confidence interval, 0.97, 1.00) at seven days (n = 17) for the bother index. Cronbach alpha reliabilities were 0.95 (95% confidence interval, 0.93, 0.97) and 0.91 (95% confidence interval, 0.89, 0.94) for the dysfunction and bother indices, respectively. Minimal ceiling and floor effects were observed for the bother subscale only. Exploratory factor analysis yielded a three-factor structure: upper-extremity dysfunction, lower-extremity dysfunction, and bother. CONCLUSIONS: A reliable and valid Brazilian Portuguese version of the SMFA was developed. It will facilitate the examination of functional performance within a large patient population as well as allow cross-cultural comparisons.

Adolescent↗
PubMed2005

Acute compartment syndrome in lower extremity musculoskeletal trauma.

Acute compartment syndrome is a potentially devastating condition in which the pressure within an osseofascial compartment rises to a level that decreases the perfusion gradient across tissue capillary beds, leading to cellular anoxia, muscle ischemia, and death. A variety of injuries and medical conditions may initiate acute compartment syndrome, including fractures, contusions, bleeding disorders, burns, trauma, postischemic swelling, and gunshot wounds. Diagnosis is primarily clinical, supplemented by compartment pressure measurements. Certain anesthetic techniques, such as nerve blocks and other forms of regional and epidural anesthesia, reportedly contribute to a delay in diagnosis. Basic science data suggest that the ischemic threshold of normal muscle is reached when pressure within the compartment is elevated to 20 mm Hg below the diastolic pressure or 30 mm Hg below the mean arterial blood pressure. On diagnosis of impending or true compartment syndrome, immediate measures must be taken. Complete fasciotomy of all compartments involved is required to reliably normalize compartment pressures and restore perfusion to the affected tissues. Recognizing compartment syndromes requires having and maintaining a high index of suspicion, performing serial examinations in patients at risk, and carefully documenting changes over time.

Compartment Syndromes↗
PubMed2005

Orthopaedic trauma for the general orthopaedist: avoiding problems and pitfalls in treatment.

The Advanced Trauma Life Support program of the American College of Surgeons has developed a de facto standard of care for the first hour of treatment of patients with trauma who are treated in North America. No equivalent for the treatment of orthopaedic trauma has been established. We provide an overview of the important topics every orthopaedist treating patients with musculoskeletal trauma should be familiar with. The topics include: (1) diagnosis of musculoskeletal injury and documentation of physical exam; (2) pelvic ring injuries; (3) open fractures; (4) compartment syndrome; (5) the timing of definitive fixation in the patient with polytrauma; (6) delayed diagnosis of musculoskeletal injury; and (7) deep venous thrombosis prophylaxis.

Clinical Competence↗
PubMed2005

Classification and initial management of patients with unstable pelvic ring injuries.

Unstable pelvic ring injuries in hemodynamically unstable patients are life-threatening emergencies that many orthopaedic surgeons encounter in practice. Therefore, it is important to be up to date regarding current methods of evaluating, assessing, and treating patients with these complex and severe injuries. Surgeons should first determine whether patients have hemodynamic instability and identify the source of the hemorrhage. Patients should then be assessed for stabilization of unstable pelvic ring injuries.

Emergency Medical Services↗
PubMed2004

Are recombinant human bone morphogenetic protein-7 and tobramycin compatible? An experiment in rats.

OBJECTIVES: To evaluate the effects of local antibiotics on bone morphogenetic protein-induced new bone formation in vivo. DESIGN: In the research laboratory, inactive collagenous bone matrix was reconstituted with 1 microg of recombinant human bone morphogenetic protein-7 and implanted subcutaneously in the thorax bilaterally in 30 male Long-Evans rats. INTERVENTION: In group A (n = 2), the inactive collagenous bone matrix alone was implanted, bilaterally, and one of these pellets treated with either 500 microg tobramycin in aqueous solution or 3 tobramycin-impregnated polymethyl methacrylate beads. In group B (n = 4), the reconstituted pellets were not treated with tobramycin. In group C (n = 8), 1 reconstituted pellet in each rat was treated with 500 microg tobramycin in aqueous solution. In group D (n = 8), 3 tobramycin beads were placed in contact with 1 of the 2 reconstituted pellets in each rat. In group E (n = 8), 3 tobramycin beads were placed on the dorsal surface of 4 of the rats. All rats were killed on day 11. MAIN OUTCOME MEASUREMENT: Bone formation was evaluated by alkaline phosphatase assay and histology. Tobramycin elution from the beads after day 11 was measured by placing the explanted beads into a phosphate buffer solution to incubate for 24 hours. RESULTS: There was no difference in the alkaline phosphatase activity between the tobramycin treated and untreated implants. Histologic evaluation of the implants revealed areas of robust new bone formation in both the tobramycin treated and untreated implants. CONCLUSIONS: The results by both alkaline phosphatase assay and histologic evaluation in this rat model indicate that there is no inhibition of recombinant human bone morphogenetic protein-7-induced new bone formation by locally applied tobramycin. Recombinant human bone morphogenetic protein-7 is osteoinductive in the presence of locally applied tobramycin. A composite osteogenic device containing both tobramycin and recombinant human bone morphogenetic protein-7 may be developed that can simultaneously induce bone healing and decrease the risk for infection.

Administration, Topical↗
PubMed2004

Pulmonary aspects of treatment of long bone fractures in the polytrauma patient.

During the past decade, there have been significant advances in the treatment of long bone fractures in the polytraumatized patient. The major controversy in this area is whether definitive long bone stabilization needs to be done emergently. In general, definitive fixation should be done early in the patient's hospital course after it is determined that the patient is hemodynamically stable and is resuscitated adequately. The major benefits of fixation are: (1). improve mobilization to enhance pulmonary function; (2). decreased narcotic requirements with improved pain control after fixation; and (3). early aggressive fluid resuscitation associated with operative intervention. Patients with multisystem injury who are underresuscitated or are unstable should have early external fixation because temporizing skeletal stabilization until definitive fixation can be done.

Arm Injuries↗
PubMed2004

The role of biomechanics and inflammation in cartilage injury and repair.

Osteoarthritis is a painful and debilitating disease characterized by progressive degenerative changes in the articular cartilage and other joint tissues. Biomechanical factors play a critical role in the initiation and progression of this disease, as evidenced by clinical and animal studies of alterations in the mechanical environment of the joint caused by trauma, joint instability, disuse, or obesity. The onset of these changes after joint injury generally has been termed posttraumatic arthritis and can be accelerated by factors such as a displaced articular fracture. Within this context, there is considerable evidence that interactions between biomechanical factors and proinflammatory mediators are involved in the progression of cartilage degeneration in posttraumatic arthritis. In vivo studies have shown increased concentrations of inflammatory cytokines and mediators in the joint in mechanically induced models of osteoarthritis. In vitro explant studies confirm that mechanical load is a potent regulator of matrix metabolism, cell viability, and the production of proinflammatory mediators such as nitric oxide and prostaglandin E2. Knowledge of the interaction of inflammatory and biomechanical factors in regulating cartilage metabolism would be beneficial to an understanding of the etiopathogenesis of posttraumatic osteoarthritis and in the improvement of therapies for joint injury.

Animals↗
PubMed2004

Development of an animal model of acetabular fractures.

A closed intraarticular fracture is a complex injury that consists of a physical disruption of the subchondral bone and articular surface, and an impaction injury to the articular surface that occurs at the time of the fracture. Few experimental models have been able to incorporate the elements of displaced articular fractures and blunt impaction injury to the articular surface. This work details the initial stages of an attempt to develop such model. Using a model of a dorsal wall fracture of the acetabulum in a goat, we have developed a bench-top method for assessing articular contact stress. Additionally, preliminary in vivo survival data are presented.

Acetabulum↗
PubMed2004

Femur fractures and lung complications: a prospective randomized study of reaming.

Reaming the intramedullary canal during fixation of femoral shaft fractures may contribute to pulmonary morbidity in patients with trauma. The purpose of our study was to compare acute and late pulmonary complications after reamed or nonreamed nailing of femur fractures. Patients who had femoral shaft fractures were randomized prospectively to a reamed (n = 41) or nonreamed (n = 41) femoral nailing group. Arterial blood gases were measured before and after femur fixation. Ratios of PaO2/FiO2 and alveolar arterial gradients were calculated. Pulmonary complications (acute respiratory distress syndrome) (ARDS), pneumonia, and respiratory failure) were monitored. Age, gender, fracture site, fracture type, time to nailing, length of operation, Injury Severity Score, and Abbreviated Injury Scale-thorax were similar for the two groups. No significant differences were observed in the ratio of PaO2/FiO2 ratios or alveolar arterial (A-a) gradients before and after nailing. The overall incidence of pulmonary complications was 14.6% (eight patients who had reamed nailing and four patients who had nonreamed nailing), and given the sample size, definitive conclusions could not be reached because of inadequate statistical power. We were unable to document differences in pulmonary physiologic response or clinical outcome between patients having reamed and nonreamed femoral nailing. This study may serve as a pilot investigation for other clinical investigations.

Adult↗
PubMed2003

Biomechanical comparison of posterior pelvic ring fixation.

OBJECTIVE: To determine relative stiffness of various methods of posterior pelvic ring internal fixation. DESIGN: Simulated single leg stance loading of OTA 61-Cl.2, a2 fracture model (unilateral sacroiliac joint disruption and pubic symphysis diastasis). SETTING: Orthopaedic biomechanic laboratory. OUTCOME VARIABLES: Pubic symphysis gapping, sacroiliac joint gapping, hemipelvis coronal plane rotation. METHODS: Nine different posterior pelvic ring fixation methods were tested on each of six hard plastic pelvic models. Pubic symphysis was plated. The pelvic ring was loaded to 1000N. RESULTS: All data were normalized to values obtained with posterior fixation with a single iliosacral screw. The types of fixation could be grouped into three categories based on relative stiffness of fixation: For sacroiliac joint gapping, group 1-fixation stiffness 0.8 and above (least stiff) includes a single iliosacral screw (conditions A and J), an isolated tension band plate (condition F), and two sacral bars (condition H); group 2-fixation stiffness 0.6 to 0.8 (intermediate stiffness) includes a tension band plate and an iliosacral screw (condition E), one or two sacral bars in combination with an iliosacral screw (conditions G and I); group 3-fixation stiffness 0.6 and below (greatest stiffness) includes two anterior sacroiliac plates (condition D), two iliosacral screws (condition B), and two anterior sacroiliac plates and an iliosacral screw (condition C). For sacroiliac joint rotation, group 1-fixation stiffness 0.8 and above includes a single iliosacral screw (conditions A and J), two anterior sacroiliac plates (condition D), a tension band plate in isolation or in combination with an iliosacral screw (conditions E and F), and two sacral bars (condition H); group 2-fixation stiffness 0.6 to 0.8 (intermediate level of instability) includes either one or two sacral bars in combination with an iliosacral screw (conditions G and I); group 3-fixation stiffness 0.6 and below (stiffest fixation) consists of two iliosacral screws (condition B) and two anterior sacroiliac plates and an iliosacral screw (condition C). DISCUSSION: Under conditions of maximal instability with similar material properties between specimens, differences in stiffness of posterior pelvic ring fixation can be demonstrated. The choice of which method to use is multifactorial.

Fracture Fixation↗
PubMed2003

Open fractures of the tibial shaft: an update.

The treatment of open fractures of the tibial shaft continues to be a challenging problem for the orthopaedic surgeon. The basic principles of treatment for open fractures have changed little over the past decade; urgent wound débridement, early use of antibiotic therapy, skeletal stabilization, and early wound coverage remain the primary goals of treatment. However, the methods used to achieve these goals of treatment have evolved. Recent advances in the treatment of open fractures focus on the treatment of open fractures of the tibial shaft.

Anti-Bacterial Agents↗
PubMedDate not supplied

Incision placement for intramedullary tibial nailing: an anatomic study.

OBJECTIVES: For intramedullary nailing of tibial shaft fractures, a recent study has determined that the entry site should be just medial to the lateral tibial spine at the anterior margin of the articular surface. Gaining access to this site is often through a medial parapatellar or transpatellar approach. Several studies have indicated that a transpatellar approach may contribute to anterior knee pain. Our study sought to use anatomic measurement to determine the ideal incision site for insertion of an intramedullary tibial nail. DESIGN Part I: survey of Orthopaedic Trauma Association (OTA) members. Part II: anatomic study. SETTING: A Level I trauma center in Sacramento, California. PARTICIPANTS: Part I: OTA members. Part II: a group of 56 healthy volunteers. INTERVENTION: Part I: questionnaire sent to OTA members. Part II: clinical examination and radiographic analysis. MAIN OUTCOME MEASUREMENTS: Part I: responses to questionnaire. Part II: anatomic measurements. RESULTS: Part I: based on a questionnaire, OTA members use at least one or more approaches to access their preferred tibial nail entry site. Fifty-seven percent use only one type of approach in all cases. Part II: the authors performed a clinical and radiographic study in 56 volunteers (112 knees) to determine the relationship of the lateral tibial spine to the patellar tendon. On the basis of this information, the tendon was divided into thirds to account for the three most common surgical approaches. The entry site was in the lateral zone in 29 knees, the middle zone in 75 knees, and the medial zone in 8 knees. If divided equally into purely a medial or lateral zone to avoid a transpatellar approach, the starting point fell into the medial zone in 42 knees and the lateral zone in 70 knees. CONCLUSIONS: Individual variations in patellar tendon anatomy should be considered when choosing the proper entry site for tibial nailing. Based on the assumption that the ideal entry point for tibial nailing is just medial to the tibial spine at the anterior margin of the articular surface, a preoperative fluoroscopic measurement before incision can guide the surgeon as to whether a medial parapatellar, transpatellar, or lateral parapatellar approach provides the most direct access to this entry site. The routine use of a single approach for all tibial nails may no longer be justified.

Adult↗