Answer:
Kanavel’s four cardinal signs of flexor tenosynovitis are:
1) Exquisite tenderness that affects the entire tendon sheath and is limited to the sheath.
2) Intense pain with passive extension of the finger, most marked at the proximal end.
3) Semiflexed finger.
4) Fusiform or symmetric swelling of the entire finger.
Gram positive cocci are usually the cause, and untreated infections can lead to skin necrosis, tendon adhesions, tendon necrosis and rupture, joint ankylosis, osteomyelitis, and deep space abscess. Loss of finger function and/or loss of finger altogether from the need for amputation are usually the endpoints of untreated tenosynovitis.
Acute flexor tendon tenosynovitis is treated by tendon sheath irrigation intraoperatively and IV antibiotics. Two approaches can be used:
The open approach essentially fillets the finger open using volar zig-zag incisions to directly drain the purulent material. The disadvantage of this approach is the exposure of delicate structures to infection with subsequent fibrosis and loss of function. There is also an increased risk of tendon necrosis and greater scarring. Secondary procedures are often required as well as prolonged rehabilitation. This approach often leads to an undesirable functional result.
The closed approach entails making limited incisions to allow drainage. Placement is variable but incisions are usually made distal to the A4 & A5 pulley at the level of the DIP and just proximal to the A1 pulley at the level of the distal palmar crease. Vigorous intraoperative irrigation is the key. Antibiotic solutions can be used but the mechanical action of the irrigant is more important than the nature of the irrigant. Some surgeons set up an irrigating system postoperatively, with catheters situated proximal and distal to the ends of the flexor sheath. The closed approach allows less scarring, less risk of desiccation and tendon necrosis, shorter hospitalization, more rapid ability to engage in active flexion and extension exercises (48-72 hours), and more rapid return to function with greater likelihood of complete recovery in function.