Presentation
Cut injury to the dorsum of the thumb 4 weeks before the presentation. Complaining of local pain, swelling, and discharge. On examination, swelling over the interphalangeal joint of the thumb and local skin changes. Extension of the interphalangeal joint was preserved.
Patient Data
There is a subcutaneous collection with internal echoes on the dorsal side of the interphalangeal joint of the thumb. The collection enters the interphalangeal joint through a defect in the middle fibers of the extensor pollicis longus tendon which measures about 5 x 5 mm. The ulnar and radial side of fibers of the extensor pollicis longus tendon shows a continuity which explained preserved extension of the interphalangeal joint. There is no obvious cartilage or bone erosion involving the joint. There is effusion with echoes in the palmar recess of the joint. Local hypervascularity is present around the collection. The Flexor tendon shows normal echopattern without tenosynovitis. There is a presence of a sesamoid bone embedded in the volar plate of the interphalangeal joint.
Case Discussion
A male patient had cut injury to the dorsum of thumb followed by local pain, swelling, and discharge. Ultrasound shows tear involving middle fibers of the extensor pollicis longus tendon through which a dorsal subcutaneous collection extended in the joint.
Surgery revealed an abscess communicating the interphalangeal joint through the tendon defect.