Bilateral Paradoxically Symptomatic Luno-triquetral Coalition: A Case Report

Oliver Lotter, MD; Stephane Stahl, MD; Oliver Luz, MD; Matthias Pfau, MD; Hans-Eberhard Schaller, MD


ePlasty. 2010;10:e47 

In This Article

Abstract and Introduction


Objective: While bony luno-triquetral coalitions are known to be asymptomatic, fibro-cartilage unions can cause ulnar-sided wrist pain. The purpose of this case report is to present a paradox clinical constellation of bilateral luno-triquetral coalition. Furthermore, recommendations for proper diagnosis and treatment options will be discussed.
Methods: The case of a 21-year-old female patient is reported, where a bony coalition of one side caused wrist pain and the contralateral fibro-cartilage bonding was asymptomatic.
Results: Because of the stable bony coalition in the symptomatic wrist, we refused to undertake a luno-triquetral fusion and continued conservative treatment with the option of wrist denervation.
Conclusions: Consequently, not only incomplete but also complete luno-triquetral coalitions can cause wrist pain. Unfortunately, no clear biomechanical explanation is available for this finding.


Luno-triquetral coalition is a congenital carpal anomaly that is most often diagnosed as an incidental finding in asymptomatic patients and can be associated with other synostoses or malformations. It is the most common coalition representing nearly 90% of all carpal fusions, followed by the capito-hamate coalition with 5.6% of all carpal fusions.[1] The prevalence in the general population averages 0.1% but is thought to be 100 times higher in Africans.[2] This anomaly is found more often in females with a ratio of 2:1.[3,4] Embryological carpal coalition represents a failure of cavitation of the cartilaginous hand bud precursor during the fourth to eighth week of gestation, which later develops to an osseous, fibrous, or cartilaginous union.[5] It is classified according to the degree of union and is often found bilateral. According to literature, the biggest collective has been reported from Senegal, where 32 luno-triquetral coalitions in 20 patients were examined in a retrospective study. The complete form (type III of Minaar's classification) was the most frequent (46.8%), followed by the incomplete osseous fusion with a distal notch (28.1%).[6,7] While synostosis of the lunate and the triquetrum is known to be asymptomatic, fibro-cartilaginous bonding can present an uncommon cause for ulnar-sided wrist pain.[8,9] This is the case of a bilateral luno-triquetral coalition causing symptoms only on the side of a stable fusion, whereas the contra lateral wrist, with an incomplete fibro-cartilaginous component, is asymptomatic.


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