Defining Nonunion for Metacarpal Fractures: A Systematic Review

Deep Learning in Scaphoid Nonunion Treatment

Background/Objectives: Scaphoid fractures are notorious for a high rate of nonunion, resulting in chronic pain and impaired wrist function. The decision for surgical intervention often involves extensive imaging and prolonged conservative management, leading to delays in definitive treatment. The effectiveness of such treatment remains a subject of ongoing clinical debate, with no universally accepted predictive tool for surgical success. The objective of this study was to train a deep learning algorithm to reliably identify cases of nonunion with a high probability of subsequent union following operative revision. Methods: This study utilized a comprehensive database of 346 patients diagnosed with scaphoid nonunions, with preoperative and postoperative X-rays available for analysis. A classical logistic regression for clinical parameters was used, as well as a TensorFlow deep learning algorithm on X-rays. The latter was developed and applied to these imaging datasets to predict the likelihood of surgical success based solely on the preoperative anteroposterior (AP) X-ray view. The model was trained and validated over six epochs to optimize its predictive accuracy. Results: The logistic regression yielded an accuracy of 66.3% in predicting the surgical outcome based on patient parameters. The deep learning model demonstrated remarkable predictive accuracy, achieving a success rate of 93.6%, suggesting its potential as a reliable tool for guiding clinical decision-making in scaphoid nonunion management. Conclusions: The findings of this study indicate that the preoperative AP X-ray of a scaphoid nonunion provides sufficient information to predict the likelihood of surgical success when analyzed using our deep learning model. This approach has the potential to streamline decision-making and reduce reliance on extensive imaging and prolonged conservative treatment.

Effect of Screw-to-Canal Diameter Ratio on Radiographic and Clinical Outcomes in Metacarpal Shaft Fractures

PURPOSE

The purpose of this study was to evaluate the influence of screw-to-canal diameter ratio on clinical and radiographic outcomes for patients with metacarpal shaft fractures treated with retrograde intramedullary headless compression screws (IMHS).

METHODS

A retrospective analysis was conducted for all patients with metacarpal shaft fractures treated with retrograde IMHS between 2017 and 2022. All procedures were performed using retrograde IMHS through an ulnar sagittal band split. Patients initiated early range of motion and were not immobilized. The ratio of screw diameter to metacarpal canal diameter at the fracture site was calculated. Radiographic displacement, QuickDASH (Disabilities of the Arm, Shoulder, and Hand) scores, grip strength, and range of motion were recorded during a 6-month follow-up period.

RESULTS

A total of 52 patients with 58 metacarpal shaft fractures treated with IMHS were included. All fractures achieved union, with 71% healed by 6 weeks and 100% healed by 12 weeks. Mean grip strength measured 86.0% relative to the contralateral side, and the average total active motion measured 248°. The mean QuickDASH score was 2.2, indicating minimal disability. No cases demonstrated extensor lag or required revision surgery. Mean screw-to-canal diameter ratio was 0.81. Oblique fractures were most likely to displace (50%), and there was a strong fit of the linear regression model for the ratio of canal fill and displacement (R2 = 0.72) among oblique fractures. No radiographic displacement occurred when the screw diameter was at least 80% of the canal diameter. Comparing patients with and without radiographic displacement, QuickDASH scores, grip strength, and mean total active motion were similar.

CONCLUSIONS

Our findings suggest that the screw-to-canal diameter ratio influences radiographic displacement in oblique fracture patterns that have a greater propensity to displace. When the screw-to-canal ratio exceeded 80%, there were no cases of displacement regardless of fracture pattern. Despite the occurrence of radiographic displacement, QuickDASH scores, grip strength, and range of motion were similar between the groups.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Clinical, Radiologic, and Functional Outcomes following Bone Grafting for Metacarpal Non-Unions: A Systematic Review

Objectives: Metacarpal non-unions are complex hand defects that can lead to severe hand impairment. Treatment may require the use of artificial or autologous bone grafts. This systematic review aims to describe the outcomes of bone grafting following metacarpal non-union in an attempt to establish an optimal therapeutic protocol for this complication. Methods: A systematic review was conducted in adherence with PRISMA guidelines. Data collection and analysis were performed in duplicate and confirmed by a third investigator. Our primary outcomes focused on radiological time to bone fusion and rates of non-union. Additionally, functional outcomes and complications were analyzed as means of central tendency. Results: Eighteen studies were included in the systematic review, accounting for a total of 47 patients. The average follow-up time was 12.4 months. Fourteen studies analyzed radiological outcomes, with atrophic non-union representing the most common type. The time to bone fusion, assessed radiologically, following bone graft was an average of 6.9 months (n = 14), with a 100% rate of union in 42 patients. Regarding patient-reported pain improvement, 76% of patients experienced pain relief. Moreover, all patients reported a complete subjective return to baseline hand function. Adverse events, limited to hematoma and seroma, were seen in three patients, representing a complication rate of 11.8% in the examined population. Conclusions: Metacarpal non-union can be treated successfully via vascularized and non-vascularized bone grafting. Based on the available evidence, bone grafts demonstrate favorable union rates, post-operative pain reduction, hand function recovery, earlier bone fusion times, and minimal complications in the context of metacarpal non-union management.

Metacarpal and Phalangeal Nonunions

The majority of phalangeal and metacarpal fractures will proceed to union when appropriately treated. However, when a nonunion does occur, it can lead to significant functional impairment for patients and societal costs. Operative intervention is typically required in these cases, but the technique can vary depending on each individual patient scenario. This article provides an overview of nonunions of the metacarpals and phalanges in the hand, including incidence, risk factors, current treatment options, and postoperative care.