Correlation between classification and secondary screw penetration in proximal humeral fractures

Preventing secondary screw perforation following proximal humerus fracture after locking plate fixation: a new clinical prognostic risk stratification model

INTRODUCTION

After locking plate (LP) fixation, secondary screw perforation (SSP) is the most common complication in proximal humerus fracture (PHF). SSP is the main cause of glenoid destruction and always leads to reoperation. This study aimed to identify independent risk parameters for SSP and establish an individualized risk prognostic model to facilitate its clinical management.

METHODS

We retrospectively reviewed the medical information of patients with PHF who underwent open reduction and internal LP fixation at one medical center (n = 289) between June 2013 and June 2021. Uni- and multivariate regression analyses identified the independent risk factors. A novel nomogram was formulated based on the final independent risk factors for predicting the risk of SSP. We performed internal validation through concordance indices (C-index) and calibration curves. To implement the clinical use of the model, we performed decision curve analyses (DCA) and risk stratification according to the optimal cutoff value.

RESULTS

A total of 232 patients who met the inclusion criteria were enrolled. The incidence of SSP was 21.98% at the last follow-up. We found that fracture type (odds ratio [OR], 3.111; 95% confidence interval [CI], 1.223-7.914; P = 0.017), postoperative neck-shaft angle (OR, 4.270; 95% CI 1.622-11.239; P = 0.003), the absence of calcar screws (OR, 3.962; 95% CI 1.753-8.955; P = 0.003), and non-medial metaphyseal support (OR,7.066; 95% CI 2.747-18.174; P = 0.000) were independent predictors of SSP. Based on these variables, we developed a nomogram that showed good discrimination (C-index = 0.815). The predicted values of the new model were in good agreement with the actual values demonstrated by the calibration curve. Furthermore, the model's DCA and risk stratification (cutoff = 140 points) showed significantly higher clinical benefits.

CONCLUSIONS

We developed and validated a visual and personalized nomogram that could predict the individual risk of SSP and provide a decision basis for surgeons to create the most optional management plan. However, future prospective and externally validated design studies are warranted to verify our model's efficacy.

Effect of Fibular Allograft Augmentation in Medial Column Comminuted Proximal Humeral Fractures: A Randomized Controlled Trial

BACKGROUND

Previous observational studies and meta-analyses have recommended augmentation with a fibular allograft (FA) during the treatment of proximal humeral fractures with locking plates (LPs). However, to our knowledge, randomized controlled trials comparing open reduction and internal fixation (ORIF) with and without FA have not been performed to date.

METHODS

This was a randomized controlled trial in which adults with a medial column comminuted proximal humeral fracture were randomly allocated to undergo ORIF with an LP (the LP group) or with an LP augmented with an FA (the FA group). Patients were followed for 24 months. The primary outcome was the Disabilities of the Arm, Shoulder and Hand (DASH) score at 12 months after the surgical procedure. The secondary outcomes included the DASH score at other time points, shoulder function, pain score, satisfaction, complications, and changes in neck-shaft angle and humeral head height.

RESULTS

From October 20, 2016, to December 24, 2019, 80 patients were randomized. There were 52 women (65%), and the mean patient age (and standard deviation) was 65 ± 14 years. Of the 80 patients, 39 were allocated to the FA group and 41 were allocated to the LP group. At the primary time point (12 months), the unadjusted mean between-group difference in DASH score was -1.2 (95% confidence interval [CI], -7.3 to 5.0; p = 0.71) favoring the FA group, and, with adjustment for smoking, alcohol drinking, and diabetes, the between-group difference was -1.4 (95% CI, -7.7 to 5.0; p = 0.67) favoring FA. No significant differences between the 2 groups were found among the secondary outcomes.

CONCLUSIONS

No additional benefit was found for FA augmentation in treating medial column comminuted proximal humeral fractures.

LEVEL OF EVIDENCE

Therapeutic Level II . See Instructions for Authors for a complete description of levels of evidence.

A novel method to assess intraarticular screw penetration into the joint space

Objectives

This study aims to propose a novel method to detect articular penetration of screws by relying on their electrical conductivity properties and control the validity of this method.

Materials and methods

In this ex vivo study, conducted between June 2017 and August 2017, we used five fresh sheep shoulder joints. First, the shoulder joint space was filled with saline solution. An insulated cannula was placed in the joint capsule, and a conductive wire was introduced into the joint via this cannula. A single titanium screw was inserted from the tuberculum majus into the posteroinferior quadrant of the humeral head under fluoroscopic observation. Conductivity was continuously measured using a digital multimeter. When a sudden decrease in conduction resistance was detected, fluoroscopic images were obtained in the anteroposterior (AP) and lateral directions. These images were assessed for penetration by a blinded surgeon. Penetration was confirmed by dissection of the joint.

Results

There was a significant decrease in electrical resistance when screw penetration occurred (p<0.001). All penetration events were confirmed using our novel method. For all five of the specimens, either AP or lateral images could not be used to confirm penetration. For two of these specimens, penetration was undetectable in both AP and lateral fluoroscopic images, but a decrease in resistance was recorded.

Conclusion

The described method exhibits greater sensitivity and accuracy for metal penetration to joint, and it is effective in detecting screws in the joints. The novel method described in this paper was applied in a prototype setting, and we believe that this concept can continue to be developed.

The plate fixation strategy of complex proximal humeral fractures

PURPOSE

For complex proximal humeral fractures, severe displacement and comminuted fragments lead to poor clinical outcomes. Despite considerable management, the locking plate fixation is still a preference and the proper selection of its strategy for each individual seems to be essential.

METHOD

The available classification system of the fracture, determination of surgical intervention, the common complications and related causes, and the latest critical surgical strategies with locking plate fixation were discussed in this review.

RESULTS

The frequent complications with complex proximal humeral fractures after operative treatment present a great challenge to orthopedic surgeons. In order to maintain the stability of locking plate fixation, several options including calcar screw, bone graft, bone cement augmentation, dual plate fixation, and fracture impaction were available for restoration of medial support.

CONCLUSION

Restoration of medial support seems of importance to provide solid stability and reduced complication for the complex fractures with fixation of locking plates.

Secondary Perforation Risk in Plate Osteosynthesis of Unstable Proximal Humerus Fractures: A Biomechanical Investigation of the Effect of Screw Length

Secondary perforation of screws into the joint surface is a commonly reported mechanical fixation failure mode in locked plating of proximal humerus fractures (PHF). This study investigated the influence that screws tip to joint distance (TJD) has on the biomechanical risk of secondary screw perforation and the stability of PHF. Ten pairs of cadaveric proximal humeri with a wide range of bone mineral density were used. Each specimen was osteotomized and instrumented with the PHILOS plate, simulating a highly unstable 3-part fracture. Bones were randomized into a long screw group (LSG) with 4 mm TJD, or a short screw group (SSG) with 8 mm TJD. A custom biomechanical setup was used to test the samples to failure cyclically with a constant valley load and an increasing ramp. The number of cycles to the initial screw loosening event was significantly higher for the LSG (mean ± standard deviation: 17,532 ± 6,458) compared with the SSG (11,102 ± 5,440) (p < 0.01). The mode of failure during testing was lateral-inferior displacement combined with varus collapse, with calcar screws perforating first. The number of cycles to failure event for LSG (27,849 ± 5,648) was not significantly different compared with SSG (28,782 ± 7,307) (p = 0.50). Screws that purchase closer to the joint had better initial stability and resistance against loosening. Placing longer screws, within limits dictated by the surgical guide, is expected to decrease the risk of secondary perforation failures in unstable PHF. These findings require clinical corroboration. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2625-2633, 2019.

Optimal viewing angles of intraoperative fluoroscopy for detecting screw penetration in proximal humeral fractures: a cadaveric study

Background

To identify the optimal viewing angles for every proximal screw in PHILOS plate-fixed proximal humeral fractures.

Methods

Three fresh-frozen human cadaveric bodies with six intact shoulders were studied. All three bodies were put in the beach chair position and PHILOS plates were placed on the proximal humerus. Head screws penetrating 1 mm into the joint were fitted one by one. Fluoroscopy was conducted in the 180° horizontal plane and the 120° coronal plane to analyze each screw’s penetration in every shoulder. Images were taken every 5°, then all images were analyzed to identify the sensitive angles.

Results

The range of optimal viewing angles to visualize penetration of every head screw was identified. In the coronal plane, the angles in the range between 0° and 10° were sensitive to all screws except No. 8 and No. 9. Furthermore, penetration of screws No. 8 and 9 could not be identified on any axillary view, but could be identified in the horizontal plane from − 30° to − 10° and from 10° to 35° respectively.

Conclusions

We recommend a 0°–10° axillary view with 30° arm abduction combined with two horizontal angles in the range of − 30° to − 10° and 10° to 35° for routine fluoroscopy during surgery. Our results will be helpful in avoiding primary screw penetration.