Search PubMed⌕ Search

Biomedical subjects

Toni M McLaurin

Publications and source records attributed to Toni M McLaurin.

4 recordsLinked to original sources

Preoperative assessment of tibial nail length: accuracy using digital radiography.

This study was performed to determine if picture archiving communication systems can provide a more accurate method of determining implant length for intramedullary tibial nailing. Postoperative radiographs of 40 patients who underwent intramedullary nailing of their tibial shaft fractures using picture archiving communication systems were retrieved. In phase one and two of this investigation, tibial nail lengths were measured using "measuring distance" and "measure calibration" tools displayed on the respective digital systems. Phase 3 of this study involved 5 tibial Sawbones (Pacific Research Laboratories, Vashon, Wash) radiographically captured on the picture archiving communication systems with a radiograph marker of known length. Using the "measuring distance" and "measure calibration" tools in phases one and two did not result in accurate measurements. Of 40 digital radiographic images measured and calibrated with the on-screen ruler and using the digital system tools, 100% of our measurements were inaccurate. An average of 19.4-mm and 10.6-mm difference was noted in uncorrected measurements on anteroposterior (AP) and lateral views, respectively. An average 25.8 mm and 15.7 mm was noted in calibrated (corrected) measurements on AP and lateral views respectively. Digitally measured and calibrated lengths were an average 22 mm and 25 mm greater from the actual known length of the tibial nail, respectively. Phase 3 of our study presented the most accurate results in length determination of tibial nail length.

Body Weights and Measures↗

Proximal humerus fractures in the elderly are we operating on too many?

Proximal humerus fractures in the elderly are a relatively rare injury, the treatment of which remains controversial, especially regarding Neer displaced two-part, and three-part and four-part fractures. Operative indications for most displaced proximal humerus fractures in the elderly remain poorly defined, but recent literature is actually supporting less aggressive approaches except for the most severe fractures. Recent epidemiological and larger scale retrospective studies fail to show a significant functional difference between operative and non-operative treatment of displaced two-part and three-part fractures in the elderly. Most four-part fractures appear to be best treated with hemiarthroplasty. Recent meta-analyses show a need for well-executed, randomized, prospective studies that can be used to provide evidence-based templates for appropriate management of displaced proximal humerus fractures in the elderly.

Age Factors↗

Screw pullout strength: a biomechanical comparison of large-fragment and small-fragment fixation in the tibial plateau.

OBJECTIVES: To compare the pullout strengths of 6.5-millimeter diameter partially threaded cancellous screws and 4.5-millimeter diameter fully-threaded cortical screws versus 3.5-millimeter diameter cortical screws in the proximal tibia. DESIGN: Three screws were inserted in the lateral tibial plateau of each leg of fifteen paired cadaveric tibias. In one tibia, large-fragment fixation was used, consisting of a unicortical 6.5-millimeter screw in the subchondral bone, and bicortical 4.5-millimeter screws in the metadiaphyseal and diaphyseal bone. In the contralateral tibia, small-fragment fixation consisting of three 3.5-millimeter screws was used, placing the screws in the same positions as described above. MAIN OUTCOME MEASUREMENTS: A materials-testing machine was used to determine axial pullout strengths of each screw. The mean pullout strengths of large-fragment and small-fragment screws in each position were compared. RESULTS: No significant difference in pullout strengths was found between the large-fragment and small-fragment screws in subchondral and metadiaphyseal bone. A statistically significant difference was found between pullout strengths of large-fragment and small-fragment screws in diaphyseal bone. CONCLUSIONS: In human proximal tibial bone, the data from this study do not suggest that the pullout strength of 3.5-millimeter screws differs from that of 6.5-millimeter screws in subchondral bone, or that the pullout strength of 3.5-millimeter screws differs from that of 4.5-millimeter screws in metadiaphyseal bone. However, the pullout strength of 3.5-millimeter screws is significantly less than that of 4.5-millimeter screws in diaphyseal bone. The authors of the present study believe this supports the use of small-fragment fixation in the treatment of tibial plateau fractures.

Biomechanical Phenomena↗