Outcomes after plating of olecranon fractures: A multicenter evaluation.

INTRODUCTION: The aim of this study was to report the physical and functional outcomes after open reduction internal fixation of the olecranon in a large series of patients with region specific plating across multiple centres. PATIENTS/METHODS: Between January 2007 and January 2014, 182 consecutive patients with a displaced olecranon fracture treated with open reduction internal fixation were included in this study. Retrospective review across four trauma centres collected elbow range of motion, DASH scores, hardware complications, and hardware removal. Postoperative visits in the outpatient clinic were at two, six, and twenty-four weeks. After 24 weeks, patients were eligible for hardware removal if symptomatic. All patients were contacted, at least 1 year following surgery, to determine if hardware was removed. RESULTS: 182 patients (75 women, 105 men) average age 50 (16-89) with 162 closed and 19 open displaced olecranon fractures were treated with one region specific plate. Nineteen were lost to followup leaving 163 for analysis with all patients united. The most common deficiency was a lack of full extension with 39% lacking at least 10° of extension. Hardware was asymptomatic in 67%, painful upon leaning in 20%, and restricted activities in 11% resulting in a 15% rate of hardware removal. Hardware complaints were more common if a screw was placed in the corner of the plate (P=0.004). When symptomatic, the area of the plate that was bothersome encompassed the whole plate in 39%, was at the edge of the plate in 33%, and was a screw head in 28%. The DASH scores, collected at final follow-up of 24 weeks, was 10.1±16, indicating moderate disability was still present. Patients who lacked 10° of extension had a DASH of 12.3 as compared with 10.5 for those with near full extension, but this was not significant (P=0.5). CONCLUSION: Plating of the olecranon leads to predictable union. The most common complication was lack of full extension with 39% lacking more than 10°, although this did not have any effect on DASH scores. Overall results indicate that disability still exists after 6 months with an average DASH score of 10. LEVEL OF EVIDENCE: Therapeutic level III.

Effect of distal interlocking screw number and position after intramedullary nailing of distal tibial fractures: a biomechanical study simulating immediate weight-bearing.

OBJECTIVE: To quantify the changes in biomechanical stability conferred by the addition of a single medial blocking screw or a single bicortical interlocking screw to 2 existing distal points of screw fixation in a distal tibial fracture model repaired with intramedullary nailing. METHODS: After simulation of a distal tibial metaphyseal fracture, 21 synthetic tibiae were repaired with an intramedullary nail and: (1) two bicortical locking screws placed in the 2 most distal screw holes (IM-L2); (2) three distal bicortical locking screws (IM-L3); and 2 distal locking screws and a single blocking screw positioned in the sagittal plane on the medial aspect of the nail (IM-L2B). The specimens were tested under combined cyclic axial and torsional loading for up to 16k cycles. The former was stepwise increasing, whereas the latter was with constant amplitude in internal rotation. RESULTS: All constructs survived 12k cycles without hardware deformation or failure. IM-L3 constructs displayed the highest baseline axial stiffness at the beginning of the test (1130.9 ± 246.9 N/mm), which was significant compared with the IM-L2 construct (701.8 ± 189.57 N/mm, P = 0.004). No significant difference in baseline axial stiffness was identified between the IM-L3 and IM-L2B constructs (881.1 ± 182.4 N/mm, P = 0.125). Relative varus interfragmentary deformation at baseline was smaller in the IM-L3 treatment group (1.3 ± 0.3 degrees) relative to the IM-L2 group (2.4 ± 0.7 degrees, P = 0.012). No differences in torsional rigidity or relative interfragmentary torsional deformation were identified between groups (P > 0.168). Failure was breakage or backout of the distal bicortical screws, fracture of the distal fragment, or proximal screw breakage. There was no significant difference in number of cycles to failure between instrumentation groups (IM-L2: 14,345 ± 1438 cycles; IM-L3: 15,634 ± 626 cycles; and IM-L2B: 14,862 ± 1511 cycles, P = 0.184). CONCLUSION: Results suggest that each of the constructs tested here may be a biomechanically viable option allowing for immediate weight-bearing after fixation of fractures of the distal third of the tibia. The addition of a single bicortical interlocking screw to create 3 points of distal fixation improves construct stiffness while reducing interfragmentary motion relative to 2 interlocking points of screw fixation with or without a blocking screw.

Biomechanical analysis of an interbody cage with three integrated cancellous lag screws in a two-level cervical spine fusion construct: an in vitro study.

BACKGROUND CONTEXT: Despite an increase in the clinical use of no-profile anchored interbody cages (AIC) for anterior cervical discectomy and fusion (ACDF) procedures, there is little published biomechanical data describing its stabilizing effect relative to the traditional anterior plating technique over two contiguous levels. PURPOSE: To biomechanically compare the acute stability conferred by a stand-alone interbody fusion device with three integrated fixation screws ("anchored cage") with a traditional six-hole rigid anterior plate in a two contiguous levels (C4-C5+C5-C6) fusion construct. We hypothesized that the anchored cage would confer comparable segmental rigidity to the cage and anterior plate construct. STUDY DESIGN: A biomechanical laboratory study using cadaveric human cervical spines. METHODS: Seven (n=7) cadaveric human cervical spines (C3-C7) were subjected to quasistatic, pure-moment loading (±1.5 Nm) in flexion-extension (flex/ext), right/left lateral bending (RB/LB), and right/left axial rotation (RR/LR) for the following test conditions: intact; after discectomy and insertion of the AIC at C4-C5 and C5-C6 with anchoring screws engaged; after the removal of the integrated anchoring screws and instrumentation of an anterior locking plate (ALP) over both levels; and cage-only (CO) configuration with screws and anterior plate removed. Intervertebral range of motion (ROM) at the instrumented levels was the primary biomechanical outcome. RESULTS: Flex/ext, RB/LB, and RR/LR ROMs were significantly reduced (p<.001) over both levels by AIC and ALP constructs relative to the CO construct. Significant reduction in flex/ext motion was achieved with the ALP (6.8±3.7) relative to the AIC (10.2°±4.6°) (p=.041) construct. No significant differences were seen in ROM reductions over the two levels between the AIC and APL groups in lateral bending or axial rotation (p>.826). CONCLUSIONS: The anchored cage fusion construct conferred similar acute biomechanical stability in lateral bending and axial rotation ROMs relative to rigid anterior plating. We identified a statistically significant reduction (Δ=3.4°, combined over two levels) in sagittal plane ROM conferred by the ALP relative to the AIC construct. Our biomechanical findings may support the clinical use of no-profile integrated interbody devices over two contiguous levels in ACDF.

Postero-lateral disc prosthesis combined with a unilateral facet replacement device maintains quantity and quality of motion at a single lumbar level.

BACKGROUND: Mechanically replacing one or more pain generating articulations in the functional spinal unit (FSU) may be a motion preservation alternative to arthrodesis at the affected level. Baseline biomechanical data elucidating the quantity and quality of motion in such arthroplasty constructs is non-existent. PURPOSE: The purpose of the study was to quantify the motion-preserving effect of a posterior total disc replacement (PDR) combined with a unilateral facet replacement (FR) system at a single lumbar level (L4-L5). We hypothesized that reinforcement of the FSU with unilateral FR to replace the resected, native facet joint following PDR implantation would restore quality and quantity of motion and additionally not change biomechanics at the adjacent levels. STUDY DESIGN: In-vitro study using human cadaveric lumbar spines. METHODS: Six (n = 6) cadaveric lumbar spines (L1-S1) were evaluated using a pure-moment stability testing protocol (±7.5 Nm) in flexion-extension (F/E), lateral bending (LB) and axial rotation (AR). Each specimen was tested in: (1) intact; (2) unilateral FR; and (3) unilateral FR + PDR conditions. Index and adjacent level ROM (using hybrid protocol) were determined opto-electronically. Interpedicular travel (IPT) and instantaneous center of rotation (ICR) at the index level were radiographically determined for each condition. ROM, ICR, and IPT measurements were compared (repeated measures ANOVA) between the three conditions. RESULTS: Compared to the intact spine, no significant changes in F/E, LB or AR ROM were identified as a result of unilateral FR or unilateral FR + PDR. No significant changes in adjacent L3-L4 or L5-S1 ROM were identified in any loading mode. No significant differences in IPT were identified between the three test conditions in F/E, LB or AR at the L4-L5 level. The ICRs qualitatively were similar for the intact and unilateral FR conditions and appeared to follow placement (along the anterior-posterior (AP) direction) of the PDR in the disc space. CONCLUSION: Biomechanically, quantity and quality of motion are maintained with combined unilateral FR + PDR at a single lumbar spinal level.

Repeated administrations of human umbilical cord blood cells improve disease outcomes in a mouse model of Sanfilippo syndrome type III B.

Sanfilippo syndrome type III B (MPS III B) is an inherited disorder characterized by a deficiency of α-N-acetylglucosaminidase (Naglu) enzyme leading to accumulation of heparan sulfate in lysosomes and severe neurological deficits. We have previously shown that a single administration of human umbilical cord mononuclear cells (hUCB MNCs) into Naglu knockout mice decreased behavioral abnormalities and tissue pathology. In this study, we tested whether repeated doses of hUCB MNCs would be more beneficial than a single dose of cells. Naglu mice at 3 months of age were randomly assigned to either a Media-only group or one of three hUCB MNC treatment groups--single low dose (3 × 10(6) cells), single high dose (1.8 × 10(7) cells), or multiple doses (3 × 10(6) cells monthly for 6 months) delivered intravenously; cyclosporine was injected intraperitoneally to immune suppress the mice for the duration of the study. An additional control group of wild-type mice was also used. We measured anxiety in an open field test and cognition in an active avoidance test prior to treatment and then at monthly intervals for 6 months. hUCB MNCs restored normal anxiety-like behavior in these mice (p < 0.001). The repeated cell administrations also restored hippocampal cytoarchitecture, protected the dendritic tree, decreased GM3 ganglioside accumulation, and decreased microglial activation, particularly in the hippocampus and cortex. These data suggest that the neuroprotective effect of hUCB MNCs can be enhanced by repeated cell administrations.