Findings
Radiographs show cystic changes/radiolucency along the ulnar border of the proximal lunate. The MRI shows edema pattern and cystic changes of the lunate. There is degeneration and fissuring of the articular disc of the triangular fibrocartilage complex (TFCC) with the dorsal and palmar radioulnar ligaments being intact. Cartilage wear is seen about the proximal aspect of the lunate.
Diagnosis: Ulnolunate Abutment Syndrome
Ulnocarpal abutment (ulnolunate being the most common) is a painful condition along the ulnar side of the wrist. The pathology relates to underlying ulnar positive variance which allows abnormal contact between the ulna and a carpal bone (in this case the lunate). This leads to breakdown of the articular cartilage and edema pattern of the carpal bone. Although ulnar positive variance is frequently found on the radiographs, it is not always apparent. As in this case, there is often a breakdown of the articular disc of the TFCC that allows a transient positive ulnar variance and the pathology about the lunate. Splinting and conservative measures are tried at first but often surgical intervention in some manner to shorten the ulna is necessary.
References
Biswas S. Ulnolunate impaction syndrome. Eplasty. 2015 Jan 8;15:ic2. PMID: 25671053; PMCID: PMC4294177.
Claudius D. Jarrett, Mark E. Baratz. The Management of Ulnocarpal Abutment and Degenerative Triangular Fibrocartilage Complex Tears in the Competitive Athlete. Hand Clinics, Volume 28, Issue 3, 2012, Pages 329-337, ISSN 07490712, ISBN 9781455738700, https://doi.org/10.1016/j.hcl.2012.05.018.