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J Wrist Surg 2022; 11(04): 302-306
DOI: 10.1055/s-0041-1735982
Scientific Article

Is DISI Deformity Related to Presence of a Medial Lunate Facet in Patients with Scapholunate Dissociation?

Sofie Goeminne 
1   Department of Orthopaedic Surgery, AZ Herentals, Herentals, Belgium
,
Laura Lemmens
2   Department of Orthopaedic Surgery, UZ Leuven, Leuven, Belgium
,
Ilse Degreef
2   Department of Orthopaedic Surgery, UZ Leuven, Leuven, Belgium
› Author Affiliations Funding None.
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Abstract

Background Lunate morphology has been suggested to influence carpal kinematics.

Purpose We investigate a possible relation between presence of a medial lunate facet and dorsal intercalated segment instability (DISI) of the wrist in patients with a scapholunate (SL) dissociation.

Methods We retrospectively reviewed patients diagnosed with SL dissociation between 2000 and 2017. Lunate morphology was categorized based on radiographs and magnetic resonance imaging (MRI), as type I or II according to Viegas and Galley. DISI was defined as radiolunate angle > 15 degrees and SL instability as SL angle > 60 degrees. SL distance > 3 mm was considered as widening and carpal height ratio < 0.5 was considered as carpal collapse. We used descriptive statistics to report on SL instability and DISI in patients with Viegas type I and type II lunates. We calculated kappa to determine agreement between radiographs and MRI and to determine inter- and intraobserver agreement.

Results Of 119 patient files, 79 wrists met the inclusion criteria of which 25 were type I lunates and 54 type II. Similar spreading of the data of both groups was found regarding DISI, SL instability, and SL widening based on radiographic classification of the lunate, even after adding MRI findings. In the presence of carpal collapse, capitate-to-triquetrum distance was higher. We found a substantial inter- and intraobserver agreement for lunate classification.

Conclusion Our results suggest a similar prevalence of DISI deformity or enlarged SL angle in patients with type I or II lunate in presence of SL dissociation. The Viegas classification is a reliable and reproducible classification system.

Level of evidence This is a Level III, cross-sectional study design.

Keywords

scapholunate instability - lunate morphology - wrist kinematics

Ethical Approval

This study was approved by the Ethical Board of Leuven University Hospital.




Publication History

Received: 23 June 2021

Accepted: 18 August 2021

Article published online:
01 October 2021

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