Locking Plates versus Locking Intramedullary Nails Fixation of Proximal Humeral Fractures Involving the Humeral Shaft: A Retrospective Cohort Study

Finite element method-based simulation on bone fracture fixation configuration factors for biodegradable embossed locking compression plate

As an evolution, biodegradable implants need to maximize mechanical performance thereby may lead to confusion in selection of the biodegradable material and implant design to the fracture site. This requires selecting a unique fixation configuration to fit within the fractured bone, factors of which can be bone-plate clearance, interfragmentary gap, alteration in screw fixation position and variation in the number of screws whose configuration optimization can re-maximize the mechanical performance of the biodegradable implant. Therefore, these factors have been optimized based on the induced minimum stress using the finite element method-based simulation for which biodegradable embossed locking plates (BELCP) via screws made of Mg-alloy have been fitted over two fragments of femur body (as hollow cylindrical cortical bone). An average human weight of 62 kg is applied to one segment of the femur for all different configurations of each factor, where another segment is assumed to be fixed. By this simulation, the most optimal fixation configuration was found at a minimum induced stress value of 41.96 MPa which is approximately 85%, 18%, 6% and 48% respectively less than all maximum stress induced configurations in each of the factor. This optimized configuration was at the minimum clearance between bone and plate with a 3 mm interfragmentary gap using 8 screws where the locking screw begins to apply from the center of the BELCP. Overall, BELCP may be a better biodegradable implant plate for bone fracture fixation with these optimized fixation configurations as the improved mechanical performance after experimental validation.

Stabilization of Comminuted Fractures of the Proximal Humerus with Intramedullary Nails and Angularly Stable Locking Plates—Functional Results before and during the SARS-COVID-19 Pandemics

Background and Objectives: Intramedullary nailing (IMN) and angularly stable plating (ASP) are the most popular techniques for the stabilization of comminuted fractures of the proximal humerus, without either one being obviously superior. The aim of the study was to validate the functional outcomes of both stabilization techniques in the COVID-19 pandemic by comparing them with data obtained just before the pandemic, because the limitations of the COVID-19 pandemic are affecting several aspects of social and medical life—being afraid of the transmission of the infection, patients reduce their exposure to healthcare to absolutely essential emergencies. Moreover, working conditions in the operating theater have also become more restrictive. Materials and Methods: Investigations were performed on 112 adult patients with Neer’s three- and four-fragment fractures stabilized with IMN (64) and ASP (48). Treatment effects were validated six months after surgery based on radiographs for evidence of bone union, humeral neck–shaft angle (NSA) and implant placement. Limb function was assessed with the QuickDash and Constant–Murley scores. Data obtained from patients treated in the COVID-19 pandemic were compared with those obtained before the pandemic. Results: The healing of all fractures was satisfactory, but complications developed in six cases. Three patients required secondary interventions due to inadequate repositioning: one after IMN and two after ASP. Additionally, one ASP was complicated by the secondary destabilization of a primarily properly stabilized major tubercle, and in two cases by conflict of the protruding implant with the acromion. ASP was noted to provide better functional results during the COVID-19 pandemic according to the Constant–Murley score (p = 0.0048; Student’s t-test). No significant differences were observed in the pre-COVID-19 pandemic. Conclusions: Our results suggest that ASP is more beneficial for the stabilization of comminuted fractures of the proximal humerus during the COVID-19 pandemic.

Biomechanical analysis of helical versus straight plating of proximal third humeral shaft fractures

BACKGROUND

Proximal humeral shaft fractures are surgically challenging and plate osteosynthesis with a long straight plate is one operative treatment option in these patients although endangering the radial nerve distally. Helical plates potentially avoid the radial nerve by twisting around the humeral shaft. Aim of the study was to investigate in a human cadaveric model the biomechanical competence of helical plates versus straight lateral plates used for fixation of proximal third comminuted humeral shaft fractures.

METHODS

Eight pairs of humeral cadaveric humeri were instrumented using either a long 90°-helical plate (Group1) or a straight long PHILOS plate (Group2). An unstable proximal humeral shaft fracture was simulated by means of a 5 cm osteotomy gap. All specimens were tested under quasi-static loading in axial compression, internal and external rotation, and bending in four directions. Subsequently, progressively increasing cyclic loading in internal rotation until failure was applied and interfragmentary movements were monitored by motion tracking.

RESULTS

During static testing flexion/extension deformation in Group1 was significantly higher, however, varus/valgus deformation as well as shear and torsional displacement under torsional load remained statistically indifferent between both groups. During cyclic testing shear and torsional displacements were both significantly higher in Group1 compared to Group 2. However, cycles to catastrophic failure remained statistically indifferent between the groups.

CONCLUSIONS

From a biomechanical perspective, although 90°-helical plating is associated with higher initial stability against varus/valgus collapse and comparable endurance under dynamic loading, it demonstrates lower resistance to flexion/extension and internal rotation with bigger shear interfragmentary displacements versus straight lateral plating and, therefore, cannot be considered as its real alternative. Alternative helical plate designs should be investigated in the future.

Efficacy of Intramedullary Nailing in the Treatment of Comminuted Proximal Humeral Fractures and Its Influence on Shoulder Joint Function Recovery

In this paper, we have aimed to elucidate the therapeutic effect of intramedullary nailing (IMN) in treating comminuted proximal humeral fractures (CPHFs) and its influence on the recovery of shoulder joint function. For this purpose, 60 cases with CPHFs were selected, particularly from January 2020 to October 2021. In these cases, 28 cases were treated with a locking proximal humeral plate (LPHP) and assigned to the control (Con) group and the remaining 32 patients were treated with IMN and included in the research (Res) group. The therapeutic effect, surgical indicators, total complications, visual analogue scale (VAS) score, and postoperative shoulder joint function score were compared between the two arms. We observed that compared with the Con group, the effective rate in the Res group was higher while the operation time, intraoperative blood loss, and fracture healing time were shorter, the overall complication rate and VAS score were lower, and the postoperative shoulder joint function score was higher, all with statistical significance. The above results indicate that IMN is effective and safe in the treatment of CPHFs, which can validly reduce the discomfort of patients and facilitate the recovery of shoulder joint function.