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J Wrist Surg
DOI: 10.1055/a-2702-0620
Scientific Article

The ABC Algorithm for Staging Scaphoid Nonunions

Authors

  • Marion Burnier

    1   Institut Chirurgical de la main et du Membre Supérieur, Hopital Jean Mermoz, Lyon, France
    1   Institut Chirurgical de la main et du Membre Supérieur, Hopital Jean Mermoz, Lyon, France

  • Fernando Corella

    2   Orthopedic and Trauma Department, Hospital Universitario Infanta Leonor, Madrid, Spain
    3   Hand Surgery Unit, IOTAM Group, Hospital Universitario Quironsalud Madrid, Madrid, Spain
    4   Department of Surgery, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain
    1   Institut Chirurgical de la main et du Membre Supérieur, Hopital Jean Mermoz, Lyon, France

Funding Information None.
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Abstract

Background

Scaphoid nonunion is a common and disabling condition in wrist surgery, associated with high rates of instability, chronic pain, and progressive degenerative changes. Due to the scaphoid's unique vascular anatomy and complex biomechanics, treatment decision-making remains challenging, and standardized staging protocols are lacking. Current imaging modalities alone often fail to provide sufficient accuracy in evaluating key parameters such as stability, vascularity, and associated ligament or cartilage injuries.

Purpose

This study introduces and evaluates a new pre- and intraoperative classification system—the ABC algorithm—which integrates preoperative imaging with arthroscopic findings to stage scaphoid nonunions more accurately and reproducibly.

Materials and Methods

The ABC algorithm categorizes scaphoid nonunions based on three components: (A) associated ligament injuries, (B) bone characteristics (including defect size, stability, fragmentation, and vascularity), and (C) cartilage status. Arthroscopic evaluation was performed systematically, using standardized portals and validated diagnostic techniques such as the hook test, rocking chair sign, and Outerbridge/International Cartilage Repair Society cartilage grading. A novel five-type arthroscopic bone classification was proposed based on stability, defect size, bleeding, and proximal pole fragmentation.

Results

Arthroscopy enabled direct, minimally invasive evaluation of joint integrity, providing reliable differentiation between stable and unstable nonunions, and precise identification of cartilage lesions and ligament injuries. The algorithm also provided immediate assessment of bone vascularity, a crucial determinant of prognosis and treatment approach, particularly in selecting between structural and vascularized bone grafts. The classification proved applicable even in revision surgeries, demonstrating adaptability across surgical expertise levels.

Conclusion

The ABC algorithm is a simple, comprehensive, and practical staging system for scaphoid nonunion that combines the strengths of advanced imaging and wrist arthroscopy. By providing detailed insights into articular, ligamentous, and osseous pathology, it enables better-informed surgical decisions and facilitates outcome comparisons in future multicentric studies. While further validation is warranted, this algorithm holds promise as a standard reference for both open and arthroscopic management of scaphoid nonunion.

Keywords

arthroscopy - classification - scaphoid nonunion - wrist arthroscopy

‡ Both authors have contributed equally to the work and should be considered co-first authors.




Publication History

Received: 04 August 2025

Accepted: 10 September 2025

Article published online:
23 October 2025

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