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Biomedical subjects

Michael J Gardner

Publications and source records attributed to Michael J Gardner.

At least 19 recordsLinked to original sources

Case report: Echinococcus disease of the bone presenting as a femoral shaft nonunion.

Osseous hydatidosis (Echinococcus infection) is a rare parasitic bone infection that poses challenges in diagnosis and treatment. We present a novel case of osseous hydatidosis of the femoral shaft that was diagnosed at the time of surgery for a recalcitrant femoral shaft nonunion. We know of no reports of osseous hydatidosis presenting as a femoral shaft nonunion. A discussion of the challenges in diagnosis and treatment of osseous hydatidosis are discussed, and the literature on osseous hydatidosis is reviewed.

Albendazole↗

An evaluation of accuracy and repeatability of a novel gait analysis device.

INTRODUCTION: Restoration of gait is a particularly important patient-based functional outcome following lower extremity trauma. A new portable device which measures gait parameters, the IDEEA, may be particularly useful in evaluating post-traumatic gait parameters in the office setting, but the accuracy and repeatability of this device relative to standard gait laboratory footswitches are unknown. MATERIAL AND METHODS: Twelve healthy subjects were tested simultaneously using the IDEEA device and standard gait laboratory footswitches, at slow, medium, and fast speeds. Parameters evaluated were single-limb support time (SLS), double-limb support time (DLS), swing phase duration (SPD), cycle duration, and cadence. RESULTS: The repeatability between right and left measurements tended to be better for the IDEEA, and was at least as good as the foot switches. The absolute differences of the timed gait parameters between the two devices were all in the range of 0.03 s, which is within the data sampling resolution of the gait laboratory foot switches (0.04 s). Furthermore, assuming a 1-s gait cycle, these differences account for only 3% of the gait cycle, which is also well within the clinical parameters for evaluating and differentiating between treatments. CONCLUSION: This device is accurate and repeatable, and may facilitate the evaluation of gait function in post-traumatic patients in settings outside of the traditional gait laboratory.

Adult↗

The efficacy of autologous platelet gel in pain control and blood loss in total knee arthroplasty. An analysis of the haemoglobin, narcotic requirement and range of motion.

Biological materials used to assist in haemostasis following total knee arthroplasty have been the subject of much recent research. Autologous platelet gel is a substance that is derived from platelet-rich plasma extracted from the patient's blood and centrifuged perioperatively, and is applied to exposed tissues, synovium and the lining of the wound at closure. Concentrating and applying these factors directly to the wound at the end of a total knee arthroplasty procedure may lead to more complete haemostasis, a reduction in perioperative blood loss, accelerated tissue repair and decreased postoperative pain. In this study, 98 unilateral total knee arthroplasties were evaluated retrospectively, 61 of which involved the intaroperative use of platelet gel, and 37 of which served as control subjects. Outcomes analysed were postoperative haemoglobin changes, intravenous and oral narcotic requirements, range of motion on discharge and total days in hospital. Patients receiving platelet gel during surgery had less postoperative blood loss as measured by differences in the preoperative and postoperative haemoglobin on day 3 (2.7 vs. 3.2 g/dl; P=0.026). The narcotic requirement was less in the platelet gel group for both intravenous (17.0 vs. 36.3 mg/day; P=0.024) and oral (1.84 vs. 2.75 tabs/day; P=0.063) medication. This group also achieved a higher range of motion prior to discharge (78.2 vs. 71.9; P=0.052) and were discharged an average of 1 day earlier than their control counterparts. Though further prospective trials are necessary, this study indicates that the application of autologous platelet gel may lead to improved haemostasis, better pain control and a shortened hospital stay.

Administration, Topical↗

How plants tell the time.

Plants, like all eukaryotes and most prokaryotes, have evolved sophisticated mechanisms for anticipating predictable environmental changes that arise due to the rotation of the Earth on its axis. These mechanisms are collectively termed the circadian clock. Many aspects of plant physiology, metabolism and development are under circadian control and a large proportion of the transcriptome exhibits circadian regulation. In the present review, we describe the advances in determining the molecular nature of the circadian oscillator and propose an architecture of several interlocking negative-feedback loops. The adaptive advantages of circadian control, with particular reference to the regulation of metabolism, are also considered. We review the evidence for the presence of multiple circadian oscillator types located in within individual cells and in different tissues.

Arabidopsis↗

In vivo cyclic axial compression affects bone healing in the mouse tibia.

Abundant evidence exists that fracture healing can be influenced by mechanical loading. However, the specific loading parameters that are osteogenic remain unknown. We hypothesized that the bone healing response in mouse tibial osteotomies would be different with a short delay before loading compared to immediate load application, as well as with higher and lower load magnitudes applied. Eighty 12-week-old mice underwent osteotomy of the left tibia followed by intramedullary nailing. Mice were divided into six groups based on days delayed until application of load (0 days or 4 days) and amplitude of cyclic load (0.5N, 1N, or 2N). Loading regimens were applied at 1 Hz for 100 cycles per day, 5 days per week for 2 weeks, using an external device that applied axial compression to the tibia. Bone healing was assessed by both microcomputed tomography (CT) and four-point bend testing. A short delay followed by cyclic application of a relatively low load led to improved fracture healing, as determined by increased callus strength, but this enhancement disappeared as load amplitudes increased. Load initiation immediately following fracture inhibited healing, regardless of the magnitude of load applied. MicroCT measurements of calluses in the early healing stage did not predict the mechanical strength of the fractures. These findings confirm that controlled, noninvasive cyclic loading can improve the strength of healing callus. However, application of load immediately after fracture appears to be detrimental to healing. Load magnitude also plays a critical role, and must be taken into account in future studies and clinical applications. As the loading parameters necessary to enhance fracture healing become refined, external compression may be used as a potent stimulus for treating fractures with decreased biological capacity.

Animals↗

Carpal kinematics.

The motion of the eight carpal bones is extremely complex, and their accurate measurement has been hampered by their multiplanar rotations and translations, the irregularity of their shape, and the small magnitudes of movements. However, an accurate three-dimensional understanding of carpal motion is critical for academic and clinical purposes, and may play an important role in assessing surgical procedures or rehabilitation protocols.

Biomechanical Phenomena↗

Treatment of distal radius fractures with a low-profile dorsal plating system: an outcomes assessment.

PURPOSE: To evaluate objective functional and radiographic outcomes after internal fixation of acute, displaced, and unstable fractures of the distal aspect of the radius in adults by using a low-profile dorsal plating system. Our hypothesis was that the low-profile dorsal plating system would allow for a reduction of extensor tendon irritation and pain and provide stable osseous fixation. METHODS: Sixty consecutive unstable fractures in 59 patients were treated by open reduction internal fixation using a low-profile dorsal plating system. There were 29 type A, 14 type B, and 8 type C fractures (AO classification system). Fifty patients with 51 fractures returned for outcomes assessment by physical examination, plain radiographs, and completion of a validated musculoskeletal function assessment questionnaire. The minimum follow-up period was 1 year; the mean follow-up period was 24 months. Clinical evaluation was performed and plain radiographs were assessed for maintenance of immediate postoperative reduction and implant position. Objective functional assessment was obtained through the Disabilities of the Arm, Shoulder, and Hand questionnaire. RESULTS: Outcomes analysis showed no cases of extensor tendon irritation or rupture. Hardware removal was performed in 1 patient but no extensor tendon irritation or rupture was evidenced. The mean Disabilities of the Arm, Shoulder, and Hand score was 11.9; implant-related discomfort was minimal. All patients had an excellent (31 patients) or good (19 patients) result according to the scoring system of Gartland and Werley. The mean active range of motion was greater than 80% of that of the contralateral wrist in flexion/extension, pronation/supination, and ulnar/radial deviation. Extensor tendon function was unimpaired in all patients. Grip and pinch strength averaged 90% and 94% of the contralateral sides, respectively. Radiographic evaluation showed no change in fracture reduction or implant position. CONCLUSIONS: The treatment of distal radius fractures with a low-profile stainless steel dorsal plating system is a safe and effective method that provides stable internal fixation and allows for full extensor tendon glide and full metacarpophalangeal joint motion. Objective outcome testing showed uniformly good to excellent recovery of wrist and hand function in all patients. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level IV.

Adult↗

The ability of the Lauge-Hansen classification to predict ligament injury and mechanism in ankle fractures: an MRI study.

OBJECTIVES: The Lauge-Hansen classification system was designed to predict the mechanism and ligament injury patterns of ankle fractures on the basis of x-rays. The purpose of this study was to evaluate the accuracy of these predicted injury sequences using magnetic resonance imaging (MRI) in a series of patients with ankle fractures. DESIGN: Retrospective cohort. SETTING: Two university level 1 trauma centers. PATIENTS: Fifty-nine patients with operative ankle fractures who were evaluated with both x-ray and MRI were included. INTERVENTION: All patients had a standard 3-view ankle x-ray series before fracture reduction, followed by an MRI. All plain x-rays were assigned to a Lauge-Hansen category by an experienced orthopedic traumatologist. MRI studies were subsequently read by an MRI musculoskeletal radiologist for the integrity of the ankle ligaments. MAIN OUTCOME MEASUREMENTS: After evaluation of the x-rays, fractures were classified according to the system of Lauge-Hansen, and the predicted presence, sequence, and mechanism of injury was determined. These were then compared to the actual injured structures on MRI in each case, and the ability of the Lauge-Hansen system to accurately predict the complete injury pattern was determined for the entire cohort. RESULTS: Average patient age was 59 (range: 18 to 84) years. Of the 59 ankle fractures evaluated, 37 (63%) were classified as supination external rotation, 11 (19%) were pronation external rotation, 1 (2%) was supination adduction, and 10 (17%) were not classifiable on the basis of the Lauge-Hansen system. Of the 49 fractures that fit into Lauge-Hansen categories, 26 (53%) had patterns of ligamentous injury and fracture morphology that did not coincide with the Lauge-Hansen predictions. A common fracture pattern was observed in 8 of the 10 unclassifiable fractures, which included a high spiral fracture of the fibula, vertical shear fracture of the medial malleolus, posterior malleolar fracture, and complete tears of the anterior-inferior tibiofibular ligament and the interosseous membrane. In addition, over 65% of patients in this series had complete ligamentous injury and a fracture of the malleolus to which the ligament attaches. CONCLUSIONS: These results demonstrate that the Lauge-Hansen classification system may have some limitations as a predictor of the mechanism of injury and the presence of soft-tissue damage associated with ankle fractures. The identification of a novel pattern of ankle fracture also illustrates how the system fails to describe all possible fracture patterns. For these reasons, we recommend that the Lauge-Hansen system be used only as a guide in the diagnosis and management of ankle fractures and not solely relied upon for treatment decisions. Although the exact clinical implications of the variety of ligamentous injuries observed on MRI are yet to be determined, this technique may be useful in individual cases in which doubt about joint stability and soft-tissue integrity exists. Additionally, MRI may be helpful in planning surgical approaches in atypical fractures in which injury patterns are less predictable solely on the basis of x-ray.

Adolescent↗

Fixation of posterior malleolar fractures provides greater syndesmotic stability.

Syndesmotic injuries are common in ankle fractures. Traditional syndesmosis fixation may be associated with a secondary procedure. When the posterior malleolus is fractured, the posterior syndesmotic ligaments may remain intact and attached to the fragment. Our goals were to establish the incidence of syndesmotic ligament ruptures in pronation-external rotation type ankle injuries associated with posterior malleolar fractures, and to assess syndesmotic stability after fixation of the posterior malleolus compared with using a syndesmotic screw. Fifteen patients who sustained pronation-external rotation Stage 4 ankle fractures that involved the posterior malleolus were evaluated using radiographs and magnetic resonance imaging. No complete tears of the posterior-inferior tibiofibular ligament occurred. A pronation-external rotation fracture pattern with a posterior malleolar fragment was created in 10 lower extremity cadaver specimens with random fixation of the posterior malleolus or the syndesmosis. Compared with the intact specimens, stiffness was restored to 70% after fixation of the posterior malleolus, and to 40% after syndesmosis stabilization. Syndesmotic stability may be obtained more effectively by fixation of the posterior malleolus rather than by using a syndesmotic screw. Although additional clinical investigation is warranted, these concepts may be useful in eliminating syndesmotic screw fixation in select patients.

Adult↗

Vascular implications of minimally invasive plating of proximal humerus fractures.

OBJECTIVES: Open reduction and internal fixation of proximal humerus fractures through the anterolateral acromial approach, which uses the anterior deltoid raphe and axillary nerve protection, has recently been advocated as a minimally invasive technique. Several recent reports have indicated variable and unpredictable vascular injuries to the humeral-head blood supply after a proximal humerus fracture, and thus a direct approach that minimizes further vascular compromise may be preferable. The purpose of this study was to define the relationship of this surgical interval to the lateral plating zone of the proximal humerus and to the penetrating vascular supply of the humeral head. DESIGN: Cadaveric vascular injection study. SETTING: Cadaveric dissection laboratory. PATIENTS: Six cadaveric specimens. INTERVENTION: The anterolateral acromial approach was performed on six cadaveric upper-extremity specimens. A locking proximal humerus plate was applied to the lateral proximal humerus, and the axillary artery was cannulated proximal to the circumflex humeral arteries. Dyed latex polymer was injected and allowed to harden, and dissection was performed to visualize the vasculature of the proximal humerus. Plates were then removed and the specimens were further inspected to examine the blood supply. MAIN OUTCOME MEASUREMENTS: The relationship of the anterolateral acromial approach to the lateral plating zone of the proximal humerus and the vascular supply of the humeral head. RESULTS: In all specimens, the filling of the anterior and posterior vessels that supplied the humeral head were undisturbed after use of the anterolateral acromial approach and locked plating. The blood vessels to the head-penetrating vascular branches were not in the surgical field. A bare spot on the lateral proximal humerus existed in the region of the greater tuberosity, which was 30 mm wide and between two penetrating humeral-head epiphyseal vessels. The nearest penetrating vessels were close to the plate, 4 mm anterior and 7 mm posterior. The anterior humeral circumflex vessel and its ascending branch, which provides critical blood supply to the humeral head, coursed directly in the region of the deltopectoral approach. CONCLUSIONS: Minimally invasive techniques have many potential benefits for fracture healing, but new surgical approaches often must be used to take full advantage of these newer methods. Splitting the anterior deltoid raphe from the acromion distally allowed direct access to the lateral plating zone of the proximal humerus. The bare spot in this region may be a safe area for plate application, if the plate is placed appropriately with thorough knowledge of the vascular anatomy. These findings may be of particular importance if the vascular supply to the humeral head has already been partially compromised by preceding trauma. This direct approach to the lateral bare spot on the proximal humerus may minimize iatrogenic vascular injury when treating these fractures.

Aged↗

Prediction of soft-tissue injuries in Schatzker II tibial plateau fractures based on measurements of plain radiographs.

BACKGROUND: Split-depression fractures of the lateral tibial plateau (Schatzker II) are associated with a significant risk of capsuloligamentous and meniscal injury. We hypothesized that the amount of fracture depression and widening on anteroposterior (AP) plain radiographs would correlate with the incidence of injury to these structures on magnetic resonance imaging (MRI). METHODS: Sixty-two consecutive patients with Schatzker II tibial plateau fractures had a knee x-ray series and MRI preoperatively. AP plain radiographs were measured for lateral joint line depression and condylar widening, and MRIs were evaluated for injury to soft-tissue structures around the knee. For each structure, the threshold of depression and widening that led to the greatest disparity in soft-tissue injury was determined. Multiple logistic regressions were applied to calculate whether depression and/or widening above the thresholds were predictive for injury to individual soft-tissue structures. RESULTS: When depression was greater than 6 mm and widening was greater than 5 mm, lateral meniscal injury occurred in 83% of fractures, compared with 50% of fractures with less displacement (p < 0.05). When either depression or widening was at least 8 mm, medial meniscal injury occurred more frequently (depression 53%, p < 0.05; widening 78%, p < 0.05; versus neither 15%). Lateral collateral ligament and posterior cruciate ligament tears were not seen with minimally displaced fractures (< 4 mm), but the incidence of injury approached 30% with increasing displacement. CONCLUSIONS: Due to the limited availability of MRI in some centers, correlation of lateral condylar depression and widening, as measured on plain radiographs, to injury of various soft-tissue structures may be extremely helpful in planning open or arthroscopic treatment methods. Using these guidelines, Schatzker II fractures with depression or widening approaching 5 mm deserve heightened vigilance in diagnosing and treating these concomitant soft-tissue injuries.

Adolescent↗

Malreduction of the tibiofibular syndesmosis in ankle fractures.

BACKGROUND: Diagnosis and reduction of syndesmosis injuries in ankle fractures can be challenging. Previous studies have demonstrated that standard radiographic measurements used to evaluate the integrity of the syndesmosis are inaccurate. The purpose of this study was to determine the adequacy of standard postoperative radiographic measurements in assessing syndesmotic reduction compared to CT and to determine the prevalence of postoperative syndesmotic malreduction in a patient cohort. METHODS: Twenty-five patients with ankle fractures and syndesmotic instability who had open reduction and syndesmotic fixation were evaluated. All patients had a standard radiographic series postoperatively followed by a CT scan. Radiographic measurements were made by three observers to determine the tibiofibular relationship. Axial CT scan images were judged for quality of reduction of the syndesmosis by measuring the distance between the fibula and the anterior and posterior facets of the incisura. Differences between the anterior and posterior measurements of more than 2 mm were considered incongruous. RESULTS: Six patients (24%) had evidence of postoperative diastasis using the radiographic criteria, four of whom had evidence of malreduction on postoperative CT scan. Conversely, 13 patients (52%) had incongruity of the fibula within the incisura on CT scan (average 3.6 mm, range 2.0 to 8.0 mm), only four of whom had one or more abnormal radiographic measurements. In 10 (77%) of the 13 malreductions seen on CT scan, the posterior measurement was greater, indicating that internal rotation or anterior translation of the fibula may have occurred. Sensitivity of radiographs was 31% and the specificity was 83% compared to CT. CONCLUSIONS: Many syndesmoses were malreduced on CT scan but went undetected by plain radiographs. Radiographic measurements did not accurately reflect the status of the distal tibiofibular joint in this series of ankle fractures. Furthermore, postreduction radiographic measurements were inaccurate for assessing the quality of the reduction. Although we did not seek to correlate functional outcomes, the known morbidity of postoperative syndesmotic malreduction should lead to heightened vigilance for assessing accurate syndesmosis reduction intraoperatively.

Adolescent↗

Hybrid locked plating of osteoporotic fractures of the humerus.

BACKGROUND: Locked plating techniques recently have gained popularity and offer a different biomechanical approach for fracture fixation compared with traditional compression plating. In certain clinical situations, it may be preferable to employ a "hybrid" construct, in which an unlocked screw is used to assist with reduction and locked screws are subsequently used to protect the initial reduction. In the present study, we used an unstable osteoporotic fracture model of the humerus to determine (1) whether a hybrid construct behaved more like a locked construct or a conventional unlocked construct and (2) whether there was a difference between locked and unlocked constructs. METHODS: Thirty third-generation Sawbones humeri were divided into three groups of ten humeri each. A locking plate with combination holes was applied to each bone with use of either a locked construct, an unlocked construct, or a hybrid construct. To simulate purchase in osteoporotic bone, all screw-holes were drilled to 0.3 mm less than the diameter of the screw used. Each specimen was then osteotomized in the middle part of the shaft, and a 5-mm segment was removed. Oscillating cyclic torsion testing was performed to +/-10 N-m for 1000 cycles, torsional stiffness was determined at periodic cyclic intervals, and the groups were compared. RESULTS: The locked and hybrid constructs demonstrated similar behavior. The initial stiffness was similar in these two groups. At ten cycles, the locked and hybrid constructs retained 96.3% and 95.4% of their initial stiffness, respectively. During the remainder of cycling the stiffness of the locked and hybrid constructs decreased in a linear fashion (R(2) = 0.89 and 0.88, respectively), and at 1000 cycles the stiffness of the locked and hybrid constructs averaged 80.0% and 79.2% of the initial values, respectively (p = 1.0). In contrast, the unlocked constructs initially were significantly less stiff than both the locked and hybrid constructs (p < 0.001). At ten cycles the unlocked constructs retained 80.4% of their initial stiffness, and at 1000 cycles they retained only 22.3% of their initial stiffness. CONCLUSIONS: Hybrid constructs are mechanically similar to locked constructs, and both are significantly more stable than unlocked constructs under torsional cyclic loading. CLINICAL RELEVANCE: Combining screws in the hybrid configuration used in the present study did not compromise the mechanical performance of the construct. Hybrid constructs may decrease cost and may provide additional clinical value when treating fractures in osteoporotic bone.

Bone Plates↗

Unsuspected lymphoma diagnosed with use of biopsy during kyphoplasty.

BACKGROUND: Vertebral augmentation procedures are currently widely performed to treat vertebral compression fractures. In selecting appropriate patients for these procedures, it is important to distinguish the pain caused by a fracture from other causes of back pain. The purpose of this study was to determine the frequency of underlying, previously unrecognized malignant tumors in a consecutive series of patients undergoing kyphoplasty to treat vertebral compression fractures. Our hypothesis was that an unsuspected malignant tumor will exist and that a bone-marrow aspiration from the iliac crest would enhance our ability to detect a malignant tumor. METHODS: A prospective histological evaluation of vertebral body biopsy specimens from presumed osteoporotic vertebral compression fractures and a concurrent bone-marrow aspiration from the iliac crest were performed in order to identify latent hematopoietic dyscrasias. Over a four-year period, vertebral body biopsies from 523 vertebral levels as well as iliac crest bone-marrow aspirations were performed in 238 patients. Both specimens were evaluated histologically, and the prevalence of an underlying occult malignant neoplasm was determined. RESULTS: All specimens from the vertebral bodies showed signs of bone-remodeling and/or fracture-healing. However, in three patients, both the bone biopsy specimen and the bone-marrow aspirate showed evidence of B-cell lymphoma. The bone-marrow aspirate did not provide any additional information compared with the vertebral body biopsy specimen, and multiple myeloma was not identified in any patient. CONCLUSIONS: Lymphoma is an uncommon cause of a vertebral compression fracture, but on the basis of our experience in this series, we recommend that vertebral body biopsy specimens be obtained in all patients managed with kyphoplasty and vertebroplasty to rule out an unsuspected malignant tumor. However, we do not recommend the routine use of an additional bone-marrow aspiration from the iliac crest during vertebral augmentation procedures because doing so did not appear to enhance our ability to detect a malignant tumor.

Adult↗

Outbreak of multidrug-resistant Salmonella typhimurium associated with ground beef served at a school potluck.

An outbreak of gastroenteritis occurred among at least 47 persons attending a school potluck. Illness was associated with consumption of ground beef (estimated odds ratio, 16.3; 95% confidence interval, 2.2 to 338.3). Salmonella Typhimurium isolated from infected individuals and the implicated ground beef revealed identical pulsed-field gel electrophoresis patterns and was multidrug resistant. The implicated ground beef was improperly handled during the cooking process and stored above the U.S. Food and Drug Administration cooling temperature standard for >15 h before being served. This outbreak demonstrates the limitations of food safety regulations in settings where foods are prepared in the home environment for communal potlucks, bake sales, or other such gatherings held at schools, churches, or other institutions. Public health authorities should encourage school and other institutional administrators to develop policies that require dissemination of safe food preparation guidelines to prospective food handlers when such events are scheduled.

Adolescent↗

An assessment of the methodological quality of research published in The American Journal of Sports Medicine.

BACKGROUND: Evidence-based medicine has become a popular topic in academic medicine during the past several decades and more recently in orthopaedics and sports medicine. HYPOTHESIS: Articles published in The American Journal of Sports Medicine have shown an improvement in methodological quality in 2001-2003, compared with 1991-1993. STUDY DESIGN: Systematic review. METHODS: All articles published in The American Journal of Sports Medicine during the periods 1991-1993 and 2001-2003 were reviewed and classified by type of study. The use of pertinent methodologies such as prospective data collection, randomization, blinding, and controlled studies was noted for each article. The frequency of each article type and the use of evidence-based techniques were compared across study periods. RESULTS: Case series and descriptive studies decreased during the study period, from 27.4% to 15.3% (P = .00003) and from 11.9% to 5.6% (P = .001), respectively, of articles published. Prospective cohort studies increased from 4.7% to 14.1% (P = .000005), and randomized, prospective clinical trials increased from 2.7% to 5.9% of articles (P = .04). More studies tested an explicit hypothesis (P = .0000002), used prospective data collection (P = .000003), and used blinding (P = .02), and more studies identified a funding source (P = .004). CONCLUSIONS: Overall, there was a shift toward more prospective and randomized research designs published in The American Journal of Sports Medicine during 2001-2003 compared to 1991-1993, demonstrating an improvement in the methodological quality of published research.

Case-Control Studies↗

Helical plating of the proximal humerus.

The ideal treatment for fractures of the proximal humerus has not been definitively agreed upon. Several recent reports have described a technique of helical plating for proximal humeral fractures, in which the proximal plate is placed laterally on the greater tuberosity, and spirals 90 degrees distally to lie on the anterior surface of the humeral shaft. The purpose of this study was to evaluate the feasibility of helical plating using a less invasive surgical approach and placing screws percutaneously in the distal plate. Dissection of 10 cadaveric upper extremity specimens was performed, using an extended anterolateral acromial approach followed by percutaneous helical plating. With the plate secured, the neurovascular structures which crossed the anterior humerus superficial to the plate were exposed and identified. Only the musculocutaneous nerve crossed anterior to the plate and was at risk for percutaneous screw placement. The nerve location was found in a consistent location among the specimens. The danger zone for the nerve location was found to be at an average of 13.5 cm from the greater tuberosity (99% CI: 12.2-14.8 cm). Though clinical experience is necessary to validate this plating technique, it appears that avoiding this danger zone in which the musculocutaneous nerve crosses will allow safe percutaneous screw placement and permit minimally invasive plating of these fractures.

Aged↗

The incidence of soft tissue injury in operative tibial plateau fractures: a magnetic resonance imaging analysis of 103 patients.

OBJECTIVES: The goal of this study was to determine the incidence of injury to soft tissue structures of the knee in tibial plateau fractures scheduled for surgery. DESIGN: Prospective cohort. SETTING: Level I academic medical center. PATIENTS/PARTICIPANTS: One hundred three consecutive patients with acute tibial plateau fractures indicated for operative intervention. INTERVENTION: Standard x-ray examinations, including anteroposterior, lateral, and oblique views, were performed in the emergency department. Subsequently all patients had magnetic resonance imaging performed. The Schatzker and AO/OTA classifications were used to classify each fracture pattern based solely on the x-rays. Soft tissue injuries were assessed by magnetic resonance imaging. MAIN OUTCOME MEASUREMENTS: Fifteen categories of injury were determined as positive or negative on each magnetic resonance imaging, which included tears of the cruciates, collateral ligaments, menisci, and posterolateral corner. RESULTS: The overall incidence of injury to soft tissues was higher than previously reported. Only 1 patient (1%) in the series had complete absence of any soft tissue injury. Seventy-nine patients (77%) sustained a complete tear or avulsion of 1 or more cruciate or collateral ligaments. Ninety-four patients (91%) had evidence of lateral meniscus pathology. Forty-five patients (44%) had medial meniscus tears. Seventy patients (68%) had tears of 1 or more of the posterolateral corner structures of the knee. The most frequent fracture pattern was a lateral plateau split-depression (Schatzker II) (60%). No pure depression injuries (Schatzker III, AO/OTA 41-B2) were seen. CONCLUSIONS: The incidence of complete ligamentous or meniscal disruption associated with operative tibial plateau fractures was higher than previously reported. Though the clinical importance of injury to each of these structures is unknown, the treating surgeon should be aware that a variety of soft tissue injuries are common in these fractures. In addition, all fractures had at least 1 cortical split visible on magnetic resonance imaging, implying that pure depression patterns are very rare or may not exist.

Adolescent↗