Clinical and sonographic evaluation of Endobutton distal biceps brachii tendon repair: what constitutes normal post-operative appearances?

Objective Distal biceps brachii tendon (DBBT) rupture is an uncommon but functionally significant injury given the loss of supination, flexion strength and pain that often result. Prompt surgical repair is preferred in most patients. Clinicoradiological post-operative follow-up is typically performed to assess DBBT repair integrity and function, frequently using ultrasound, though to date, no studies have described post-operative DBBT repair sonographic appearances. The purpose of this study was to evaluate post-operative DBBT sonographic appearances in the context of Endobutton repair with the following aims: Establish typical ultrasound appearances 12 months post-surgery Establish the relationship between ultrasound appearances and clinical/functional outcomes. Materials and methods Sixty patients between February 2016 and October 2017 undergoing DBBT repair were prospectively recruited, all undergoing clinical and sonographic assessment 12 months post-surgery. Ultrasound data was collected on tendon integrity, tendon calibre and presence of intratendinous calcification, peritendinous fluid and peritendinous soft tissue/scarring. Clinical data was collected on active range of motion (ROM) (flexion, extension, supination, pronation) and strength (flexion and supination). Results A total of 57/60 patients had intact DBBT repairs identified sonographically and clinically at 12 months. DBBT repairs had significantly increased cross-sectional area (mean 260%, 95% CI: 217%, 303%) compared with non-operated DBBT. Ninety-three percent of DBBT repairs were hypoechoic. Thirty percent contained intratendinous calcification. Peritendinous fluid/soft tissue was rarely observed. There was no significant correlation between DBBT calibre and strength/ROM parameters. Conclusion Normal post-operative sonographic appearances of Endobutton DBBT repair comprise a hypoechoic tendon significantly increased in calibre compared with non-operated tendon +/- intratendinous calcification. DBBT repair calibre varies greatly, but is not associated with any significant difference in strength/ROM.