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J Wrist Surg
DOI: 10.1055/a-2662-1014
Wrist and Carpal Anatomy Article

Biometric and Ligaments Analysis of the Scaphotrapeziotrapezoid Joint: Implications for Arthroplasty

Thomas Albert
1   Institut de la Main - Nantes Atlantique - Bd Charles-Gautier, Saint-Herblain, France
,
Philippe Bellemère
1   Institut de la Main - Nantes Atlantique - Bd Charles-Gautier, Saint-Herblain, France
,
Andrea Atzei
2   Pro-Mano, Hand Surgery and Rehabilitation, Viale Louis Pasteur, Treviso, Italy
,
Ludovic Ardouin
1   Institut de la Main - Nantes Atlantique - Bd Charles-Gautier, Saint-Herblain, France
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Funding None.
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Abstract

Background

The periarticular ligament anatomy of the scaphotrapeziotrapezoid (STT) joint varies in the literature, complicating standardization. Preservation of this ligamentous array is critical in preventing intracarpal malalignment.

Purpose

This study aims to map ligament insertion sites on the bony components of the STT joint and define resection margins for the scaphoid, trapezium, and trapezoid during arthroplasty.

Materials and Methods

We examined 26 cadaveric wrists. Needles marked the STT joint before arthrotomy, allowing precise observation of ligament positioning intact. Ligament insertion sites on the scaphoid, trapezium, and trapezoid were measured with micrometric calipers. We recorded STT arthritis presence and distribution on the scaphoid, trapezium, and trapezoid articular surfaces. Each surface was divided into four quadrants voloulnar (VU), voloradial (VR), dorsoulnar (DU), and dorsoradial (DR).

Results

The dorsal intercarpal ligament (DIC) was the only extrinsic dorsal ligament of the STT joint. The average insertion distance from the articular surface was 3.033 mm (standard deviation [SD] = 0.693) on the trapezium and trapezoid, compared to 1.918 mm (SD = 0.329) on the scaphoid. This difference was statistically significant (p < 0.001). The palmar ligament organization resembled a rigid tripod anchored by the RS (radioscaphoid), ST (scaphotrapezial), and SC (scaphacapitate) ligaments around the scaphoid tubercle. Palmar ligament insertion points averaged 0.58 mm (SD = 0.32) from the articular surface, with no significant difference between the scaphoid and the trapezoid–trapezium complex (p = 0.558). STT arthritis was present in 80.8% of wrists. The VU sides of the STT were most affected, particularly the volar side of the trapezoid.

Conclusion

The DIC ligament and palmar ligamentous tripod, formed by the RS, SC, and ST ligaments, could acts as a mechanical lock preventing dorsal scaphoid translation. While distal scaphoid pole resection is standard, our findings suggest prioritizing proximal trapezium and trapezoid resections in arthroplasty to avoid instability.

Keywords

STT joint - wrist ligaments - arthroplasty - anatomy - arthritis

Authors' Contributions

T.A. and L.A. conducted literature searches and designed the study and analyzed the data. P.B., V.B., and A.A. participated in the development of the protocol. T.A. wrote the first draft of the manuscript. All authors reviewed and edited the manuscript and approved the final version of the manuscript.


Ethical Approval

This study was completed in accordance with the Helsinki Declaration as revised in 2024. This cadaveric study was carried out with the approval of the ethical, scientific, and educational committee, which you can find below.


Patient's Consent

Patient consent information is not required for this cadaveric anatomical study.




Publication History

Received: 17 April 2025

Accepted: 21 July 2025

Article published online:
06 August 2025

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