Selective Atrophy of the Abductor Digiti Quinti: An MRI Study

SLR - August 2009 - A. Shalonda Davidson

Reference:
Recht, M., Grooff, P., Ilaslan, H., Recht, H., Sferra, J., Donley, B. (2007). Selective atrophy of the abductor digiti quinti: An MRI Study. The American Journal of Roentgenology, 189(3), 123-127.


Scientific Literature Reviews


Reviewed by: A. Shalonda Davidson, DPM
Residency Program: OCPM-UHHS Richmond Medical Center


Podiatric Relevance:
This study provides data for the podiatric surgeon to decide whether MR findings of atrophy of the abductor digiti quinti (ADQ) muscle is a useful marker of entrapment of
the first branch of the lateral plantar nerve.

Methods:
A prospective study of all patients referred for ankle and foot MRI examinations was performed. The study included 602 patients, 387 females and 215 males ages 9 to 88. All images were evaluated for the presence or absence of selective fatty atrophy of the ADQ muscle. Atrophy was graded on a 4-point scale. The clinical notes on patients with MR findings of ADQ atrophy were analyzed by 2 orthopedic surgeons for descriptions of the symptoms leading to the MRI examination, presence of symptoms that might be related to nerve entrapment, and the alterations of clinical management related to the MRI finding of ADQ atrophy.

Results:
Thirty eight (6.3%) of the 602 patients had selective fatty atrophy of the ADQ, 29 females and 9 males. Nineteen had grade 3 atrophy (fat>muscle); 11 with grade 2 (fat=muscle); and eight with grade 1 atrophy (muscle>fat). Age range of patients with atrophy was 24 to 79 years old. Only one patient had a clinical diagnosis of possible nerve entrapment before MRI examination. MRI findings of ADQ atrophy altered clinical management in only one patient.

Conclusions:
Selective fatty atrophy of the ADQ is not a rare finding on MRI examinations of the foot and ankle, being seen in 6.3% of all studies and in 7.5% of all studies in females. The clinical relevance of selective ADQ atrophy seen on MRI is uncertain.