Linking the distal humerus columns in articular fracture fixation

INTRODUCTION

Concerning rates of nonunion in articular distal humerus fractures indicate an unsolved problem. The fixation principles of O'Driscoll describe linking the fractured articular segment to the distal humerus columns with compression screws which creates a stable fixed angle construct. A novel device has been introduced which utilizes an interlocking beam through the articular segment to connect the distal aspect of the medial and lateral plates, creating a linked construct. We sought to evaluate the stability of this linked construct using an articular model of distal humerus fracture.

MATERIALS AND METHODS

Ten matched pair specimens of 65 years of age or older were randomized to the use (LB group) or non-use (NLB group) of an interlocking beam to link the medial and lateral locking plates in fixation of an AO Type C3 fracture model. Outside of the linking beam, fixation between the matched pairs was consistent using 2.7 mm locking screws distally with fixed trajectories and +/- 2 mm lengths.

RESULTS

Mean stiffness was 273 Newtons/mm in the LB group and 225 Newtons/mm in the NLB group (p = 0.001). Mean maximum displacement was 0.28 in the LB group and 0.93 mm in the NLB group (p = 0.006). Mean load to failure was 277 pounds in the LB group and 280 pounds in the NLB group (p = 0.94).

DISCUSSION

Our results indicate that an interlocking beam which links the medial and lateral plates provides greater stability compared to a similar construct without an interlocking beam. We attribute this finding to the beam's double supported design which resists cantilever bending and provides robust compression of the fractured fragments.

Does posterior configuration have similar strength as parallel configuration for treating comminuted distal humerus fractures? A cadaveric biomechanical study

BACKGROUND

The posterior plating technique could be used as a clinical alternative to parallel plating for treating comminuted distal humerus fractures (DHFs) successfully with good clinical results. However, the biomechanical characteristics for posterior fixation are still unclear. The purpose of this study is to evaluate the biomechanical properties of the posterior fixation and to make comparisons between the parallel and the posterior fixation systems.

MATERIALS AND METHODS

We performed a cadaveric biomechanical testing with two posterior plating systems (a posterior two plating and a single posterior pre-contoured Y plating system) and one parallel two plating system to treat AO/OTA type-C2.3 DHFs. Among three groups, we compared construct stiffness, failure strength, and intercondylar width changes after 5000-cycle fatigue loading and failure loads and failure modes after destructive tests in both the axial compression and (sagittal) posterior bending directions. The correlations between construct failure loads and bone marrow density (BMD) were also compared.

RESULTS

In axial direction, there were no significant differences in the stiffness and failure load between the posterior and the parallel constructs. However, in sagittal direction, the two-plate groups (posterior two plating and parallel plating group) had significant higher stiffness and failure loads than the one-plate group (single posterior Y plating). There was no fixation failure after 5000-cyclic loading in both directions for all groups. Positive correlation was noted between BMD and failure loads on parallel fixation.

CONCLUSIONS

We found that when using two plates for treating comminuted DHFs, there were no significant differences in terms of most biomechanical measurements between posterior and parallel fixation. However, the single pre-contoured posterior Y plate construct was biomechanically weaker in the sagittal plane than the parallel and the posterior two-plate constructs, although there was no fixation failure after the fatigue test for all groups regardless of the fixation methods.

LEVEL OF EVIDENCE

Biomechanical study.

Orthogonal plating method versus parallel plating method in the treatment of distal humerus fracture: A systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis was performed to investigate the outcomes of orthogonal plating method and parallel plating method in the treatment of distal humerus fracture from the current literatures.

METHODS

The electronic literature database of Pubmed, Embase, and Cochrane library were searched in November 2018. The data operation time, union time, Mayo Elbow Performance Score (MEPS), range of motion (ROM) of elbow, arc of elbow flexion, arc of elbow extension, rate of excellent and good results and complications (including heterotopic ossification, transient ulnar nerve neuropathy and ankylosis) were extracted. Stata 14.0 software was used for our meta-analysis.

RESULTS

A total of 8 studies including 6 RCTs and 2 cohort studies met our inclusion criteria. This meta-analysis showed that there was no significant difference between the two groups regarding operation time, MEPS, ROM of elbow, arc of elbow flexion, arc of elbow extension and rate of excellent and good results at final follow-up (P = 0.50, P = 0.39, P = 0.87, P = 0.18, P = 0.58 and P = 0.59 respectively). However, the present meta-analysis demostrated that parallel plating method had significantly shorter union time than orthogonal plating method (P = 0.018). As for the complications (heterotopic ossification, transient ulnar nerve neuropathy and ankylosis), there was no significant difference between the two groups (P = 0.89, P = 0.08 and P = 0.29 respectively).

CONCLUSION

Our meta-analysis suggested that both orthogonal plating and parallel plating method could achieve satisfactory outcomes with the similarly low complications in the treatment of distal humerus fracture. More RCTs are required for further research.

Biomechanical comparison of orthogonal versus parallel double plating systems in intraarticular distal humerus fractures

OBJECTIVES

In intraarticular distal humerus fractures, internal fixation with double plates is the gold standard treatment. However the optimal plate configuration is not clear in the literature. The aim of this study was to compare the biomechanical stability of the parallel and the orthogonal anatomical locking plating systems in intraarticular distal humerus fractures in artificial humerus models.

METHODS

Intraarticular distal humerus fracture (AO13-C2) with 5 mm metaphyseal defect was created in sixteen artificial humeral models. Models were fixed with either orthogonal or parallel plating systems with locking screws (Acumed elbow plating systems). Both systems were tested for their stiffness with loads in axial compression, varus, valgus, anterior and posterior bending. Then plastic deformation after cyclic loading in posterior bending and load to failure in posterior bending were tested. The failure mechanisms of all the samples were observed.

RESULTS

Stiffness values in every direction were not significantly different among the orthogonal and the parallel plating groups. There was no statistical difference between the two groups in plastic deformation values (0.31 mm-0.29 mm) and load to failure tests in posterior bending (372.4 N-379.7 N). In the orthogonal plating system most of the failures occurred due to the proximal shaft fracture, whereas in the parallel plating system failure occurred due to the shift of the most distal screw in proximal fragment.

CONCLUSION

Our study showed that both plating systems had similar biomechanical stabilities when anatomic plates with distal locking screws were used in intraarticular distal humerus fractures in artificial humerus models.

Distal humerus fractures: a review of current therapy concepts

Fractures of the distal humerus in the adult comprise approximately one third of all humeral fractures. Successful management of distal humerus fractures depends on correct reduction of the fracture, reconstruction of the articular surface if needed, stability and rigidity of the fixation, and appropriate rehabilitation. In this review, we evaluated the available literature and highlighted current therapy concepts. We assessed the evolution of internal fixation and elbow arthroplasty focusing on the established surgical approaches against the background of a growing incidence of distal humeral fractures in an aging patient population. Therefore evaluating the aspect and influence of age-dependent comorbidities like osteoporosis on successful treatment.