The Case: 58-year-old man presented with left middle finger pain swelling and purulent discharge following what he believes to have been a splinter injury 5 days prior. On physical examination, there was fusiform swelling of the middle finger of his left hand. The finger was tender to palpation along the flexor surface from the PIP to the MCP and there was purulent discharge that could be expressed from the wound.
Why it matters: Flexor tenosynovitis is a surgical emergency. The flexor tendon sheaths are a sealed space filled with synovium to reduce friction and supply nutrients to the tendons. Because the sheath is a small nutrient rich space infection spreads rapidly and can result in tendon necrosis. Even when treated promptly, tendon adhesions resulting in decreased grip strength, reduced range of motion, or even amputation may occur.
The flexor tendon sheaths extend from the distal end of the finger and terminate at the distal palm. The 5th digit, however, communicates with the ulnar bursae and common flexor tendon sheath of the palm. Given their anatomy there are 4 key physical exam finds that lead a clinician to suspect flexor tenosynovitis; they are known as the Kanavel’s signs:
1. Excessive tenderness over the course of the tendon sheath, limited to the sheath
2. Symmetric enlargement of the whole finger
3. Excruciating pain on passive finger extension, along the entire sheath
4. Flexed resting position of the finger
On ultrasound hypoechoic/anechoic fluid can be found around the tendon sheath consistent with edema. The sheath itself will also appear thickened. Ultrasound therefore can be an adjunct diagnostic tool to help support the clinical diagnosis of flexor tenosynovitis.
Our patient had fusiform swelling, but the finger was not held in flexion, there was no pain with passive extension, and there was not tenderness over the entire length of the tendon sheath. Bedside drainage of a purulent collection of fluid was performed by the surgical consultant. A drain was placed and the patient was discharged on Augmentin with clinic follow up.
Written by:
Dr. Meredith Scott, MD
Emergency Medicine, PGY-2
Cook County Health
Reviewed by:
Dr. Scott Sherman, MD
Associate Program Director
Cook County Health
References:
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