Flexor Tendon Sheath


47YO gardener presenting 1 week after getting a thorn stuck in their finger. The affected finger is red hot and swollen and held in a fix flexion position.

I would approach this patient according to CRISP/ALS principles.

I would start of by checking the patients observations to ensure they were stable and not clinically septic.

I would then take a focused history and examination.

Pertinent features in the history would be: mechanism of injury/previous trauma, hand dominance, occupation/hobbies, walking aids, immunosuppression, constitutional symptoms, pain/erythema/swelling, smoking status. NBM status and allergies.

On examination I would look for: pain/erythema, NVI, Kanavel’s sings, axillary lymphadenopathy and tracking erythema.

I would take full trauma bloods and CRP and an X-Ray to RO foreign body.

Management would be washout and antibiotics

Kanavel’s signs

  • Fusiform swelling (97%)
  • Finger held in fixed flexion (69%)
  • Pain on palpation of flexor tendon sheath (65%)
  • Pain on extension/stretch of the flexor tendon sheath (72%)

In an appropriately marked, consented and anaesthetised individual. I would complete a WHO checklist.

Patient would be supine with an arm board.

Incision would be via a Bruner’s for open or 2 incisions: one over the A1 pully (5mm from palmar crease of finger) and one over the A5 pully (DIP crease)

Dissect down to the flexor tendon sheath and insert angiocath.

Take cultures

Washout with normal saline.

Dressing with wool and crepe, high elevation in Bradford sling

Septic shock

Infection leads to spread along the sheath causing tendon adhesions leading to stiffness and potential tendon rupture

Synovial fluids provide nutrition and lubrication to tendons

Prevent bow-stringing

Flexor sheath contains synovial fluids

Thumb has its own flexor sheath communicates with the common flexor sheath in 50% of individuals at the wrist.

The ulnar bursa consists of the tendons of the flexor digitorium superficialis and digitorum. It ends half way down the Metacarpals blindly for the 2nd, 3rd and 4th digit. These fingers have a second terminal parts of the flexor digitorum sheath.

The ring finger has a continuous tendon sheath.