An In Vitro Biomechanical Comparison of a 5.5 mm Locking Compression Plate Fixation with a 4.5 mm Locking Compression Plate Fixation of Osteotomized Equine Third Metacarpal Bones

Proximal Interphalangeal Arthrodesis in Horses: A Meta-Analysis of Retrospective Studies

The aim of this study was to determine the clinical outcomes reported in retrospective studies of proximal interphalangeal arthrodesis (PIA) in horses through a meta-analysis of retrospective studies. CAB Abstracts, PubMed, ScienceDirect, Web of Science, and Scopus were searched. The primary outcomes included survival and surgical site infection (SSI) rates, return to activities, and time of hospital stay and casting. Subgroups were formed for fractures and other conditions. Meta-analyses were performed with fixed and random effects models to estimate proportions, mean values, and effect size by odds ratio (OR) with 95% confidence intervals (CI). Twenty-one full articles were included, totaling 458 horses. The survival rate was 90% (95% CI [86%-93%]), return to activities was 65% (95% CI [61%-70%]), and SSI was 12% (95% CI [8%-16%]). The mean hospitalization was 25 days (95% CI [18-35 days]) and time of casting was 29 days (95% CI [21-42 days]). The OR of survival (P = .769), return to activities (P = .576), and SSI (P = .467) were similar between cases of fractures and other conditions. PIA is an efficient and safe method to treat injuries in the pastern region, with a high survival rate and low SSI. However, the rate of return to soundness for intended use was modest, being potentially lower for fracture cases. Thus, investigations of more efficient interventions are needed to improve this outcome.

Biomechanical properties of a novel locking compression plate to stabilize oblique tibial osteotomies in buffaloes

OBJECTIVE

Quantitation of mechanical properties of a novel locking compression plate (LCP) for bovine tibia.

STUDY DESIGN

Prospective in vitro study.

SAMPLE POPULATION

Adult Murrah buffalo (250-350 kg) tibiae.

METHODS

Forty tibiae were randomly assigned to five treatment groups (n = 8/group): intact bone and bone constructs with a standard nonlocking plate, single LCP, double LCP, and novel LCP. During implant application, a mid-diaphyseal, oblique osteotomy was performed in all constructs, which were subsequently tested in axial compression (n = 4 each) or three-point craniocaudal bending (n = 4 each). Novel LCP alone (n = 4) was tested only in bending. Stiffness, yield load, ultimate failure load, and bending moment were determined from the load deformation curves and compared among different treatment groups (P < .05).

RESULTS

Under compression, yield load of the novel LCP (24.07 ± 3.45 kN) was greater than that of the nonlocking plate (11.10 ± 2.46 kN) and the single LCP (18.01 ± 2.07 kN) but less than that of the double LCP (30.61 ± 1.95 kN), and ultimate failure load of the novel LCP (25.85 ± 4.32 kN) was greater than that of the nonlocking plate (13.18 ± 2.91 kN) but similar to that of the single LCP (21.17 ± 2.33 kN) and the double LCP (32.40 ± 1.46 kN). Bending moment, yield load, and ultimate failure load of the novel LCP were 565.37 ± 79.30 Nm, 7.90 ± 1.14 kN, 9.83 ± 1.38 kN, respectively, which were greater than those of the nonlocking plate and the single LCP but comparable to those of the double LCP.

CONCLUSION

The novel LCP developed for bovine tibia was mechanically superior to the standard nonlocking plate or the single LCP and comparable to the double LCP.

CLINICAL SIGNIFICANCE

The novel LCP may provide rigid fixation of tibial diaphyseal fractures in buffaloes and cattle weighing 250 to 350 kg.

In vitro biomechanical testing of the 3.5 mm LCP in torsion: a comparison of unicortical locking to bicortical nonlocking screws placed nearest the fracture gap

Objective

This biomechanical study compared the torsional strength and stiffness of a locking compression plate with all locking versus nonlocking screws and examined the effect of placing a locking unicortical or nonlocking bicortical screw nearest the fracture gap in a synthetic bone model.

Results

Synthetic bone models simulating a diaphyseal fracture without anatomic reduction were tested using four screw configurations: all bicortical locking (ABL), all bicortical nonlocking (ABN), a hybrid construct with a bicortical nonlocking screw nearest the fracture gap (BN), and a unicortical locking screw placed nearest the fracture gap (UL). Torsional stiffness, rotation and torque at failure were compared via ANOVA and post hoc pairwise comparisons (p < 0.05). ABN and BN had the highest stiffness (p < 0.01) with ABL greater than UL (p < 0.01). Rotation at failure was greatest for ABL (p < 0.01) with UL greater than ABN (p < 0.05). Unicortical locking screws nearest the fracture gap decreased stiffness, without significantly affecting torque or rotation at failure. Construct stiffness was found to exist in a very narrow range of 0.9–1.2 N m/deg with standard deviations of 0.1 N m/deg in all cases. The results of this study support the use of nonlocking screws in a hybrid construct to increase torsional stiffness.

Electronic supplementary material

The online version of this article (10.1186/s13104-017-3102-y) contains supplementary material, which is available to authorized users.

Single cycle to failure in torsion of three standard and five locking plate constructs

Objectives: The biomechanical properties of standard plates and recently designed locking plates were compared in torsion. We hypothesized that titanium (Ti) constructs would have the greatest deformation, and String of Pearls (SOP) constructs the greatest strength and stiffness.

Methods: Dynamic compression plates (DCP), stainless steel (SS) limited contact (LC)-DCP, Ti LC-DCP, locking compression plate (LCP), 10 mm and 11 mm Advanced Locking Plate System (ALPS) 10 and 11, SOP and Fixin plates were applied to a validated bone model simulating a bridging osteosynthesis. Yield torque (strength), yield angle (deformation) and stiffness were compared using one-way ANOVA with post hoc Tukey (p <0.05).

Results: The ALPS 11 constructs had significantly greater elastic deformation than all constructs except for the ALPS 10. There were not any differences in strength observed except for the ALPS 10 constructs, which was less than that for the SOP, LCP, DCP and ALPS 11 constructs. No differences in construct torsional stiffness were observed with the SS LCDCP, DCP, LCP and SOP constructs however all had greater stiffness than all remaining constructs. The ALPS 10 construct had lower stiffness than all constructs.

Clinical significance: Modulus of elasticity of Ti explains the higher deformation and lower stiffness of these systems, with similar results for the Fixin due to its lower section modulus compared to all other plates. The SOP and standard constructs had surprisingly similar biomechanical properties in torsion. The rationale for selecting these implants for fracture repair likely needs to be based upon their differing biomechanical properties inherent to the diverse implant systems.

Presented at the 38th Annual Conference of the Veterinary Orthopedic Society, Snowmass, Colorado, USA March 6, 2011.

In vitro biomechanical comparison of a 5-hole 4.5 mm locking compression plate and 5-hole 4.5 mm dynamic compression plate for equine proximal interphalangeal joint arthrodesis

OBJECTIVE

To compare the biomechanical properties of a 5-hole 4.5 mm narrow locking compression plate (LCP) and 5-hole 4.5 mm narrow dynamic compression plate (DCP) for equine proximal interphalangeal (PIP) joint arthrodesis.

STUDY DESIGN

Experimental mechanical study.

ANIMALS

Cadaveric adult equine forelimbs (n = 6 pair).

METHODS

For each forelimb pair, 1 PIP joint was stabilized with LCP and the contralateral PIP joint with DCP. The 6 construct pairs were tested using a single-cycle, 3-point dorsopalmar bending system. PIP joints were evaluated with pre- and post-test radiography.

RESULTS

The LCP technique had significantly greater yield load, failure load, and stiffness under single-cycle, 3-point dorsopalmar bending to failure than the DCP technique. There was no significant difference between the 2 constructs for displacement at yield and failure point.

CONCLUSIONS

Biomechanically, the LCP technique provided significantly greater stability than the DCP technique under the test condition.