Partial interosseous ligament tears of the wrist: difficulty in utilizing either primary or secondary MRI signs

Prior reports on scapholunate ligament (SLL) and lunotriquetral ligament (LTL) tears have evaluated complete tears. As these complete tears have markedly different biomechanical manifestations and surgical considerations than do partial tears, we evaluated the accuracy of MR and the usefulness of secondary MR signs to diagnose partial interosseous ligament tears.

Fifty wrists in 50 patients underwent arthroscopy following 1.5 T MR. Images were evaluated by two independent blinded observers for normal or partially torn SLL and LTL and for three secondary signs potentially seen as mechanical sequelae of tears: osseous offset, arc disruption, or focal osteoarthritis.

Arthroscopically, there were 16 SLL and 14 LTL partial tears. Accuracy of primary MR signs of partial tears was lower than that described in the literature for complete tears [sensitivity/specificity (kappa) = 0.56/0.56 (0.12)-SLL, 0.31/0.76 (0.13)-LTL]. Secondary signs showed low sensitivity but high specificity, particularly for LTL tears: arc disruption [0.17/0.83 (0.43)-SLL, 0.0/1.00 (1.0)- LTL], focal osteoarthritis [0.32/0.78 (0.18)-SLL, 0.11/0.91 (0.12)-LTL], and focal osseous offset [0.39/0.75 (0.10)-SLL, 0.26/0.93 (0.39)-LTL]. Additionally, there was poor interobserver consistency for both primary and secondary signs.

The sensitivity of morphologic evaluation for diagnosing partial intercarpal ligament tears, particularly those of the LTL, is limited. Secondary signs increase specificity but have low sensitivity, and with the exception of arc disruption, all signs had poor interobserver agreement.