Parallel versus orthogonal plate osteosynthesis of adult distal humerus fractures: a meta-analysis of biomechanical studies

Biomechanical comparison of three internal fixation configurations for low transcondylar fractures of the distal humerus

BACKGROUND

We aimed to evaluate the biomechanical stiffness and strength of different internal fixation configurations and find suitable treatment strategies for low transcondylar fractures of the distal humerus.

METHODS AND MATERIALS

Thirty 4^th generation composite humeri were used to create low transcondylar fracture models that were fixed by orthogonal and parallel double plates as well as posterolateral plate and medial screw (PPMS) configurations (n=10 in each group) using an anatomical locking compression plate-screw system and fully threaded medial cortical screws. Posterior bending (maximum 50 N), axial loading (maximum 200 N) and internal rotation (maximum 10 N·m) were tested, in that order, for each specimen. Stiffness under different biomechanical settings among different configurations were compared. Another 18 sets of fracture models were created using these three configurations (n=6 in each group) and the load to failure under axial loading among different configurations was compared.

RESULTS

Under posterior bending, the stiffness of parallel group was higher than orthogonal group (P<0.001), and orthogonal group was higher than PPMS group (P<0.001). Under axial loading, the stiffness of parallel group was higher than orthogonal group (P=0.001) and PPMS group (P<0.001); however, the difference between orthogonal and PPMS group was not statistically significant (P>0.05). Under internal rotation, the stiffness of parallel group was higher than orthogonal group (P=0.044), and orthogonal group was higher than PPMS group (P=0.029). In failure test under axial loading, the load to failure in the orthogonal group was lower than parallel group (P=0.009) and PPMS group (P=0.021), but the difference between parallel group and PPMS group was not statistically significant (P>0.05). All specimens in orthogonal group demonstrated "distal medial failure"; most specimens had "distal medial and trochlear failure" in the parallel group; most specimens exhibited "contact failure" in the PPMS group.

CONCLUSION

For treating low transcondylar fractures, the overall stiffness and strength of the parallel configuration were superior to those of the orthogonal and PPMS configurations. Nevertheless, the PPMS configuration can provide adequate stability and stiffness comparable to double-plate configurations under axial loading. Therefore, the PPMS construct may have certain clinical value.

Intra-articular Distal Humerus Fractures: Parallel Versus Orthogonal Plating

Background: Dual-plating osteosynthesis is the standard treatment for Orthopedic Trauma Association (OTA)-type 13-C distal humerus fractures. However, optimal plate position is debated. Purpose: The purpose of this study was to evaluate dual-plate positioning following intra-articular distal humerus fracture repair by comparing outcomes between patients plated in parallel and those plated orthogonally following open-reduction, internal-fixation (ORIF) of intra-articular distal humerus fractures. Methods: All OTA-type 13-C intra-articular distal humerus fractures treated operatively at our institution over a 10-year period were reviewed. Clinical outcomes and complications were compared between those plated in parallel and those plated orthogonally. Data were analyzed using independent-samples t-tests, Mann-Whitney U tests, chi-square tests, and Fisher's exact tests. Results: A total of 69 patients met inclusion criteria. Mean follow-up among this cohort was 19.3 months; 45 (64.8%) patients had orthogonal dual plating, and 24 (35.2%) had parallel plating. Groups did not differ with respect to demographics or duration of follow-up. Clinically, there were no significant differences in time to union, elbow arc of motion at any time point, or patient Mayo Elbow Performance Index (MEPI) scores at final follow-up. Furthermore, there were no differences in complications. Conclusion: Parallel and orthogonal plating following ORIF of distal humerus fractures with modern, contoured locking compression plates had similar outcomes in this study. This study represents the largest comparative series in the literature at the time of its writing. Both techniques may be considered when deciding on dual-plating technique for treating intra-articular distal humerus fractures.

The Outcomes of Intra-Articular Distal Humerus Open Reduction Internal Fixation Using Parallel Precontoured Plates in the Elderly

PURPOSE

Inconsistent outcomes have been reported in several prior studies of elderly patients with distal humerus fractures treated with open reduction and internal fixation (ORIF). We evaluated the outcomes of ORIF using modern precontoured plates exclusively in a parallel orientation.

METHODS

A retrospective review was performed to identify the patients aged over 65 years who sustained an isolated distal humerus fracture between 2015 and 2019. We identified 22 patients who underwent distal humerus ORIF using parallel, precontoured locking plates. Electronic medical records were reviewed for demographic characteristics, physical examination findings, and radiographic data. Outcomes were assessed with Quick Disabilities of the Arm, Shoulder, and Hand scores and Mayo Elbow Performance scores. Complications were evaluated by a review of the patient's medical record and postoperative radiographs.

RESULTS

Of the included patients, 18 were women and 4 were men; the average age was 78 years (SD, 8.5 years), and the patients were followed for an average of 33 months. The sample consisted of 19 AO type C, 1 type B, and 2 type A fractures. At the final follow-up, the mean arc of total elbow flexion was 107° (SD, 18.9°; range 40° to 130°), with mean elbow flexion of 129° (SD, 11.7°; range, 120° to 140°) and mean extension of 22° (SD, 12.9°; range 0° to 90°). The mean Quick Disabilities of the Arm, Shoulder, and Hand score was 19 (SD, 14.4), and the mean Mayo Elbow Performance score was 86 (SD, 10.2). Complications occurred in 5 (23%) patients, requiring 4 subsequent surgeries, of which 1 was a conversion to total elbow arthroplasty.

CONCLUSIONS

Older patients who underwent ORIF of the distal humerus using a parallel construct demonstrated good functional outcomes and similar complications to those in previously reported studies.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Modified pin and plate fixation for low intercondylar fractures of the humerus: biomechanical study corroborated with a case series

BACKGROUND

Establishing fracture union of low and comminuted intercondylar fractures of the humerus is inherently challenging. The purposes of the present study were to investigate the biomechanical effectiveness of pin & plate (PP) fixation compared to other dual-plating techniques by finite element analysis, and to present a technical description as well as retrospectively review the outcomes of PP fixation in such difficult fractures.

METHODS

Low-level intercondylar fracture 3D models of the humerus were virtually stabilized with three fixations on lateral side including PP, lateral pre-contoured locking compression plate (L-LCP), and variable angle lateral pre-contoured locking plate (VA-L-LCP) whereas medial pre-contoured locking compression plate (M-LCP) on medial side. Loading conditions under consideration were axial compression, internal rotation, posterior bending, and valgus rotation. Regarding the clinical series, eight patients with intra-articular and comminuted fractures of the distal humerus (6 intercondylar fractures, 1 fracture-subluxation, and 1 isolated lateral condylar fracture) were operated by isolated PP fixation or combinations of PP and the other standard implants. Data were collected on fracture union, perioperative complications, and objective clinical outcomes.

RESULTS

Biomechanical results revealed the most instability of the fracture occurring under posterior bending. PP fixation presented comparable fracture stability and fragment displacement compared to other dual-plating fixations, except stress on the Kirschner wire under internal rotation which was higher than other fixations. Regarding the clinical series, fracture union was achieved in all cases with an average union time of 17 weeks (range 12-20). All except one patient had good-to-excellent MEPS results with an average Disabilities of the Arm, Shoulder, and Hand (DASH) score of 14.6 (range 0-45) and an average arc of elbow motion of 107.5 degrees (range 60-140).

CONCLUSION

By the biomechanical performance, PP fixation is a reliable technique for fixation of low intercondylar fractures of the humerus. Supported by the clinical outcomes, the present technique could be an alternative for this particular fracture especially when severe comminution prevents the use of the standard dual plating technique.

Radiographic Evaluation of Elbow Fractures

Fractures and dislocations of the elbow are a common cause of emergency department visits each year. Radiography remains the bedrock of an initial injury assessment, and recognition of distinctive injury patterns based on fracture location, morphology, and severity, guides optimal clinical decision-making. This article reviews basic elbow anatomy, frequently seen fractures and injury patterns, and highlights how these findings influence surgical planning and patient management.

Dynamic effect of three locking plates fixated to humeral fracture based on multibody musculoskeletal model

OBJECTIVE

This study attempts to analyse the biomechanical effect of internal fixation (plated in parallel or plated vertically) on the basis of distal humeral fractures on musculoskeletal multibody dynamics using AnyBody in Finite Element Method.

METHOD

Humeral 3D models were reconstructed by MIMICS after volunteers' CT image input in *.dicom format, and processed by Geomagic Studio for surfaces, while locking plates and screws were then designed by Pro-E. A humeral model of T-type fracture was created and assembled in Hypermesh, to integrate fixtures (e.g., MPL/PML/ML), to grid the mesh and then assign materials. A musculoskeletal model of the upper limb was established by AnyBody to simulate elbow flexion and extension. They were finally imported to Abaqus for boundary conditions and dynamic analysis.

RESULT

In terms of Von Mises stress, its maximum increased and then decreased gradually during the joint motion, but p > 0.05 in SPSS suggests no significant difference for all three fixtures. In terms of displacement, when the elbow was at 90°, each motional pattern reached its peak as follows: ML180° = 0.28 mm, MPL90° = 0.49 mm & PML90° = 0.54 mm during flexion; ML180° = 0.073 mm, MPL90° = 0.10 mm & PML90° = 0.12 mm during extension. p < 0.05 suggests a significant difference for the displacements of all three fixations. p = 0.007 < 0.01667 suggests the significant difference between the two fixations, for example, PML90° and ML180°, indicating that the peak displacement of ML180° is less than that of PML90°.

CONCLUSION

After generally analysed in musculoskeletal dynamics, the biomechanical property of the fixtures was presented as follows: the displacement of the parallel plate was less than that of the vertical, and the parallel plate may optimise the clinical reduction anatomically.

Low-profile double plating of unstable osteoporotic olecranon fractures: a biomechanical comparative study

BACKGROUND

In the treatment of unstable olecranon fractures, anatomically preshaped locking plates exhibit superior biomechanical results compared with tension band wiring. However, posterior plating (PP) still is accompanied by high rates of plate removal because of soft-tissue irritation and discomfort. Meanwhile, low-profile plates precontoured for collateral double plating (DP) are available and enable muscular soft-tissue coverage combined with angular-stable fixation. The goal of this study was to biomechanically compare PP with collateral DP for osteosynthesis of unstable osteoporotic fractures.

METHODS

A comminuted displaced Mayo type IIB fracture was created in 8 osteoporotic pairs of fresh-frozen human cadaveric elbows. Pair-wise angular stable fixation was performed by either collateral DP or PP. Biomechanical testing was conducted as a pulling force to the triceps tendon in 90° of elbow flexion. Cyclical load changes between 10 and 300 N were applied at 4 Hz for 50,000 cycles. Afterward, the maximum load was raised by 0.02 N/cycle until construct failure, which was defined as displacement > 2 mm. Besides failure cycles and failure loads, modes of failure were analyzed.

RESULTS

Following DP, a median endurance of 65,370 cycles (range, 2-83,121 cycles) was recorded, which showed no significant difference compared with PP, with 69,311 cycles (range, 150-81,938 cycles) (P = .263). Failure load showed comparable results as well, with 601 N (range, 300-949 N) after DP and 663 N (range, 300-933 N) after PP (P = .237). All PP constructs and 3 of 8 DP constructs failed by proximal fragment cutout, whereas 5 of 8 DP constructs failed by bony triceps avulsion.

CONCLUSION

Angular-stable DP showed comparable biomechanical stability to PP in unstable osteoporotic olecranon fractures under high-cycle loading conditions. Failure due to bony triceps avulsion following DP requires further clinical and biomechanical investigation, for example, on suture augmentation or different screw configurations.

Optimal Fixation of the Capitellar Fragment in Distal Humerus Fractures

OBJECTIVES

To determine if orthogonal or parallel plate position provides superior fixation of the separate capitellar fragment often present in intra-articular distal humerus fractures. We hypothesized that orthogonal plating would provide stiffer fixation given a greater number of opportunities for capitellar fixation and screw trajectories perpendicular to the fracture plane offered by a posterolateral plate compared with a parallel plate construct.

METHODS

Ten matched pairs of cadaveric distal humeri were used to compare parallel and orthogonal plating in a fracture gap model with an isolated capitellar fragment. The capitellum was loaded in 20 degrees of flexion using a cyclic, ramp-loading protocol. Fracture displacement was measured using video tracking software. The primary outcome was axial stiffness for each construct. Secondary outcomes included maximum axial and angular fracture displacement.

RESULTS

The parallel plate construct was more than twice as stiff as the orthogonal plate construct averaged across all loads (1464.8 ± 224.0 N/mm vs. 526.3 ± 90.8 N/mm, P < 0.001). Average axial fracture displacement was 0.15 ± 0.03 mm versus 0.53 ± 0.10 mm for parallel versus orthogonal plating, respectively (P = 0.003). Angular fracture displacement was minimal for both constructs (0.009 ± 0.001 degrees vs. 0.028 ± 0.006 degrees for parallel vs. orthogonal constructs).

CONCLUSIONS

Despite fewer points of fixation, a parallel plate construct provided stiffer fixation with less displacement of the simulated capitellar fracture fragment than an orthogonal plate construct in this biomechanical study. In the setting of an articular fracture, in which absolute stability and primary bone healing are desirable, parallel fixation should be considered even in fractures with a separate capitellar fragment if the size of fragment and fracture orientation allows.

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.

DOUBLE PLATING FOR FRACTURES IN GIANT ANTEATERS (MYRMECOPHAGA TRIDACTYLA)

The fixation of fractures in wild animals has been a great challenge for veterinarians, because they will inevitably face a unique anatomical characteristic with scarce studies or reports published. Fracture fixation should promote adequate stability and early return to limb function, taking into account biomechanical characteristics of the bones, body weight, and natural habits of wildlife. Three bone fractures from two giant anteaters (Myrmecophaga tridactyla) referred at the veterinary teaching hospital on different occasions were treated by a double plating technique. The two free-ranging anteaters incurred their injuries when struck by an automobile. The first anteater (Ant 1) had a complete oblique fracture of the proximal third of the right femur and a complete comminuted fracture of the distal third of the right tibia. Surgical stabilization was performed by double plating to stabilize the femur and tibia. The second anteater (Ant 2) had a complete transverse fracture of the mid-diaphysis of the right radius and ulna, and it was fixed with a medial plate on the radius and a caudal plate on the ulna. The patients were able to walk 24 hr after the surgical procedures. Bone consolidation was observed at 60 days postoperatively, with no complications. The biggest challenges were related to anatomical characteristics for surgical approaches and the ability to promote a fixation strong enough to support the weight and strength of the animal, allowing early return to limb function.

[Sub- and intercondylar fractures of the distal humerus in adults]

Introduction

les fractures articulaires complètes de l’extrémité inférieure de l’humérus de l’adulte sont des lésions rares et graves. Les options thérapeutiques sont nombreuses mais le traitement chirurgical par ostéosynthèse est ardemment défendu. L’objectif de notre travail a été de décrire les caractéristiques épidémiologiques, clinico-radiologiques et thérapeutiques de ces fractures, ainsi que d’évaluer les résultats fonctionnels obtenus chez nos patients.

Méthodes

nous avons mené une étude prospective sur une période de 3 ans, portant sur 38 patients admis pour fracture articulaire complète sus et inter-condylienne de l’humérus distal (classée type C selon la classification de l’AO), traités chirurgicalement par voie postérieure trans-olécranienne avec un recul moyen de 34 mois.

Résultats

nous avons remarqué une distribution bimodale avec une atteinte du sujet jeune de sexe masculin d’une part, et une survenue chez les femmes âgées d’autre part. Les étiologies étaient dominées par les accidents de la voie publique chez 78%. Lors du suivi, nous avons noté un seul cas d’infection superficielle du site opératoire et il n’y a eu aucun cas de démontage du matériel ni de pseudarthrose. De surcroit, aucune complication de l’ostéosynthèse de l’olécrane n’a été enregistrée. Les résultats fonctionnels ont été très satisfaisants avec un score de Mayo-Clinic Elbow Performance Score (MEPS) moyen de 86.

Conclusion

nous considérons que la voie postérieure trans-olécranienne semble être la meilleure voie d’abord de ces fractures puisqu’elle permet une bonne exposition articulaire, condition sine qua non pour une restitution anatomique parfaite et une ostéosynthèse stable afin d’entreprendre une rééducation précoce et adaptée.

Biomechanical Comparison of External Fixation and Double Plating for Stabilization of a Canine Cadaveric Supracondylar Humeral Fracture Gap Model

OBJECTIVE

 Successful stabilization of comminuted supracondylar humeral fractures is challenging, and biomechanical studies are scarce. This study compares double-plate (DB-PLATE) and linear external fixator with an intramedullary pin tie-in (ESF-IMP) fixation techniques in a cadaveric gap model. The hypothesis was the DB-PLATE construct would be stiffer, stronger and more resistant to repeated loading than the ESF-IMP construct in both cyclic and load-to-failure axial compression testing.

STUDY DESIGN

 A 2 cm ostectomy was performed on 10 pairs of canine cadaveric humeri proximal to the supratrochlear foramen. Stabilization was with DB-PLATE (n = 10) or ESF-IMP (n = 10). Cyclic testing was performed by applying a 200 N load at 2 Hz for 63,000 cycles. Axial compressive load to failure testing followed. Data analysed included dynamic stiffness, stiffness and yield load.

RESULTS

 No constructs failed during cyclic testing or lost stiffness over time. Mean dynamic stiffness over the final 100 cycles was greater for DB-PLATE compared with ESF-IMP. Mean stiffness of DB-PLATE in load-to-failure testing was not different than ESF-IMP. Yield load of DB-PLATE was higher than ESF-IMP.

CONCLUSION

 Both DB-PLATE and ESF-IMP survived cyclic testing with no change in dynamic stiffness. DB-PLATE was stronger than ESF-IMP in load-to-failure testing, which may make this construct preferable when prolonged healing or poor patient compliance is anticipated. Results suggest that either method may be appropriate for fixation of comminuted supracondylar humeral fractures.