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Biomedical subjects

Jeff C Brand

Publications and source records attributed to Jeff C Brand.

6 recordsLinked to original sources

A biomechanical comparison of the FasT-Fix meniscal repair suture system and the RapidLoc device in cadaver meniscus.

PURPOSE: This biomechanical study compared the fixation characteristics of horizontally or vertically implanted FasT-Fix devices (Smith & Nephew, Endoscopy Division, Andover, MA) consisting of two 5-mm PLLA suture T-bar anchors with a pretied self-sliding knot (No. 0 nonabsorbable, USP, braided polyester suture material) and the RapidLoc device (Mitek Surgical Products, Westwood, MA) consisting of a PLLA T-bar anchor or "backstop," a connecting suture (No. 2 nonbiodegradable Ethibond; Ethicon, Somerville, NJ), and a PLLA grommet, for repairing posterior third lesions in human menisci. TYPE OF STUDY: Controlled laboratory biomechanical study. METHODS: After repair of a vertical longitudinal meniscus lesion with either vertically or horizontally implanted FasT-Fix devices or RapidLoc devices, 3 groups of 6 specimens underwent cyclic loading (5 mm/minute, cycling between 5 and 50 N at 1 Hz for 500 cycles) before load to failure testing on a servo hydraulic device. One-way analysis of variance and Tukey HSD post hoc tests were used to evaluate group differences (P < .05). RESULTS: The vertical FasT-Fix device group (3.2 +/- 0.49 mm) had less displacement after cyclic testing than either the horizontal FasT-Fix (4.4 +/- 0.73 mm, P = .003) or the RapidLoc (4.6 +/- 0.22 mm, P = .002) device groups. The vertical FasT-Fix device group had greater stiffness during cyclic testing (14.4 +/- 2.1 N/mm) than the horizontal FasT-Fix (10.4 +/- 1.6 N/mm, P = .0001) or the RapidLoc (9.7 +/- 0.44 N/mm, P = .0001) device groups. During load to failure testing, the vertical FasT-Fix group (125.3 +/- 39 N) had 28% greater strength than the horizontal FasT-Fix device group (89.7 +/- 14 N, P = .02) and 30% greater strength than the RapidLoc device group (87.1 +/- 13 N, P = .028), whereas displacement and stiffness did not show statistically significant group differences. CONCLUSIONS: The vertical FasT-Fix group had superior biomechanical characteristics for meniscal fixation during cyclic and load to failure testing compared with horizontal FasT-Fix or RapidLoc devices. CLINICAL RELEVANCE: Although the RapidLoc devices provided fixation characteristics comparable to horizontally implanted FasT-Fix devices, vertically implanted FasT-Fix devices may provide superior all-inside fixation.

Absorbable Implants↗

Soft-tissue interference fixation: bioabsorbable screw versus metal screw.

PURPOSE: To compare the biomechanical properties of eccentrically positioned bioabsorbable and titanium interference screws for quadrupled hamstring tendon graft (QHTG) fixation. TYPE OF STUDY: In vitro, biomechanical study. METHODS: In 10 paired cadaveric tibiae and femurs (mean age, 66.5 years; range, 53 to 81 years), QHTG fixation was performed in tunnels sized to within 0.5 mm of QHTG diameter using either a titanium (RCI; Smith & Nephew Donjoy, Carlsbad, CA) or a bioabsorbable (BioScrew; Linvatec, Largo, FL) screw of equal size. Constructs then underwent biomechanical load-to-failure testing on a servo-hydraulic device at 20 mm/min. RESULTS: Load at failure was greater for femoral-side QHTG fixation using the bioabsorbable screw than the titanium screw (486 +/- 223.7 N v 246 +/- 99.1 N, P = .006); however, displacement did not differ (P = .81). There were no statistically significant differences between groups for tibial side load at failure (P = .54), stiffness (P = .44), or displacement (P = .50). Screw thread-induced graft laceration was more frequently observed in the titanium screw group (9 of 10 grafts during femoral-side testing, 0 of 10 grafts during tibial-side testing) than in the bioabsorbable screw group (0 of 10 grafts during femoral-side testing, 1 of 10 grafts during tibial-side testing). CONCLUSIONS: BioScrew interference screw fixation was comparable or superior to RCI titanium interference screw fixation. BioScrew interference screw fixation also produced less screw thread-induced laceration of the QHTG during load-to-failure testing. CLINICAL RELEVANCE: Use of a biodegradable interference screw positioned directly against a soft-tissue graft provides fixation properties similar to those of a metal interference screw.

Absorbable Implants↗

A biomechanical comparison of initial soft tissue tibial fixation devices: the Intrafix versus a tapered 35-mm bioabsorbable interference screw.

BACKGROUND: Biomechanical testing of the Intrafix device has not been performed using human tibiae. HYPOTHESIS: The Intrafix device would provide comparable or superior tibial fixation of a quadrupled hamstring tendon graft to a 35-mm-long bioabsorbable interference screw. STUDY DESIGN: In vitro, biomechanical study. METHODS: Eight paired human tibiae and 16 quadrupled hamstring tendon grafts were divided into 2 groups. Each quadrupled hamstring tendon graft was fixed in a tunnel sized to 0.5 mm graft diameter with either an Intrafix device or a screw. RESULTS: Displacement at failure was greater in the Intrafix group (17.3 +/- 4.6 mm versus 10.9 +/- 4.4 mm, P =.002). Load at failure (796 +/- 193 N versus 647 +/- 269 N), stiffness (49.2 +/- 21.9 N/mm versus 64.5 +/- 22 N/mm), and bone mineral density (0.74 +/- 0.15 gm/cm(3) versus 0.74 +/- 0.14 gm/cm(3)) did not display significant differences for the Intrafix device and the screw, respectively (P >.05). CONCLUSIONS: Displacement at failure was greater for the Intrafix device. CLINICAL RELEVANCE: Increased displacement at failure for the Intrafix group suggests slippage from sheath channel deployment. Concentric fixation may not occur when less than optimal tibial bone mineral density increases the difficulty of attaining precise sheath deployment and quadrupled hamstring tendon graft strand alignment.

Bone Screws↗

Correlation of bone tunnel diameter with quadrupled hamstring graft fixation strength using a biodegradable interference screw.

PURPOSE: The purpose of this study was to determine whether the ultimate load at failure of a quadrupled hamstring tendon graft (QHT) fixed with a biodegradable interference screw is improved with a more precise match of the bone tunnel diameter to the diameter of the QHT. TYPE OF STUDY: Biomechanical testing. METHODS: In group A, 8 cadaver knees with a mean age of 69.4 years (range, 60 to 76) were used. QHT graft diameters were measured using sleeves in standard 1.0-mm increments, with matching bone tunnels drilled in 1.0-mm increments. In group B, 9 cadaver knees, with a mean age of 66.5 (53 to 81) were used. Grafts were measured using sleeves in 0.5-mm increments and matching bone tunnels in 0.5-mm increments were drilled. In both groups, the QHT grafts were fixed with a biodegradable interference screw (BioScrew, Linvatec, Largo, FL) in both the tibia and the femur. Tendon interference fixation was tested to failure using a material testing device that tensioned the grafts directly in line with the bone tunnels. Bone mineral density was measured using dual photon absorptimetry for the metaphyseal area of the tibias and femora in the area of interference screw fixation. RESULTS: Femoral maximum load at failure significantly improved from 341 N in the 1.0-mm group to 530 N (P <.05) in the 0.5-mm group; the tibial maximum load at failure improved from 221 N to 308 N (P =.35). CONCLUSIONS: Fixation strength results of this study suggest that commercially available instrumentation could be improved with sleeves and reamers available in 0.5-mm increments.

Absorbable Implants↗

Radiographic analysis of femoral tunnel position in postoperative posterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to test the hypothesis that plain radiographs are accurate in assessing femoral tunnel positions in posterior cruciate ligament (PCL) reconstruction. TYPE OF STUDY: Cadaveric study. METHODS: Femoral tunnels were drilled in cadaveric distal femurs using standard techniques at the 12 o'clock, 1:30, and 3 o'clock positions in the left femora and at the 12 o'clock, 10:30, and 9 o'clock positions in the right femora. At each of the three positions, a 9-mm tunnel was drilled with its anterior edge 2 mm posterior to the articular surface of the medial femoral condyle (MFC). Posterior or "malpositioned" tunnels were drilled with the anterior edge 11 mm posterior to the articular surface of the MFC. Four radiographs; a true lateral, a 10 degrees externally rotated lateral, a 10 degrees internally rotated film in the sagittal plane, and an anteroposterior (AP) radiograph were then taken of each tunnel with a radiopaque dilator in the tunnel. All radiographs were analyzed with the 4-quadrant method (4 is the posterior quadrant) and the ratio method (0 is anterior and 1 is posterior). The AP radiograph was measured using a new technique, the intersection of the angle of a line through the center of the femoral tunnel and a line placed tangential to the femoral condyles. RESULTS: Means were calculated for each of the 6 tunnel positions on the 4 radiographs (lateral, external rotation, internal rotation, and AP). Of the 15 comparisons among tunnel postions, 13 could be discriminated using the lateral and AP radiographs. The high-anterior (HA) (12 o'clock position) could not be differentiated on any radiograph from the high-posterior (HP) (12 o'clock position). The internally rotated lateral radiograph could discriminate the midanterior (MA) (1:30 and 10:30 positions) from the low-anterior (LA) (the 3 and 9 o'clock positions). CONCLUSIONS: Three radiographs; the AP, lateral, and internally rotated lateral, can be used to detect a significant difference in the majority of tunnel locations. The tunnel positions that could not be differentiated with these measurements were posterior and may not be clinically important. We concluded that a plain radiograph is an accurate indicator of PCL tunnel position.

Cadaver↗