Modified Ultrasonographic Classification of Tendinous Mallet Injuries Based on a Combination with Wang Classification...

Background: Although ultrasonography is useful for assessing soft-tissue injuries, its role in classifying tendinous mallet injuries remains underdefined. This study aimed to propose a modified ultrasonographic classification system that combines Wang's classification with additional subtypes emphasising lateral band involvement to improve diagnostic accuracy and prognostic assessment. Methods: A retrospective cross-sectional study was performed on 36 patients with acute closed tendinous mallet injuries of the fingers. All patients underwent ultrasonographic evaluation. Based on the modified classification, Wang Type B was subdivided into Subtype B1 (complete terminal tendon rupture) and Subtype B2 (rupture of either the radial or ulnar slip of the lateral band). Clinical outcomes were recorded at a minimum of 4 months of follow-up. Data on pinch strength, pain, extension lag and functional scores were analysed to compare outcomes across the three injury types. Results: Fifteen Type B1, eight Type B2, and 13 Type C injuries were identified. In all types, as the length of the injured tendon increased, pinch strength relative to the contralateral side was significantly weaker. Additionally, the injured tendon was significantly longer in Type C injuries than in Type B1 and B2 injuries. As the length of the injured tendon increased, pinch strength relative to the contralateral side decreased across all injury types. Nevertheless, the pain score, functional score and initial extension lag did not show statistically significant variations amongst injury types. Crawford criteria showed that Types B2 and C injuries were mostly graded as 'excellent' or 'fair', whereas Type B1 injuries were more often classified as 'poor' or 'fair'. Conclusions: The modified ultrasonographic classification provides a more detailed framework for assessing tendinous mallet injuries by integrating Wang's classification and distinguishing partial lateral band ruptures. This approach enhances diagnostic precision and may improve functional prognostication. Level of Evidence: Level IV (Diagnostic).