Differential Diagnosis of Trigger Finger

Courtesy: Prof Nabil Ebraheim, University of Toledo, Ohio, USA

DIFFERENTIAL DIAGNOSIS OF TRIGGER FINGER

LUMBRICAL PLUS FINGER
• When the patient tries to flex the fingers,the involved digit will be extended

SAGITTAL BAND INJURY
• Sagittal band injury can give rise to trigger (In sagittal band injury there is subluxation and relocation of the extensor tendon),
• snapping and subluxation of the tendon is noticed at the top of the knuckle when moving from extension to flexion
• The patient is unable to actively extend the finger from fully flexed flexed position, but the
finger can be maintained in place once it is passively extended
• IN BOTH CASES THE MIDDLE FINGER IS AFFECETED

JOINT CONTRACTURE
• The patient may have a history of trauma
• The patient will be unable to actively or passively extend the finger

FLEXOR TENOSYNOVITIS
• The four positive Kanavel signs:

Fusiform swelling of the finger
Flexed posture of the finger
Tenderness along the sheath of the finger
Inability to actively extend the finger with intense pain when attempting to straighten the finger

FLEXOR DIGITORUM PROFUNDUS AVULSION
• The avulsed tendon ends can retract proximally and may become entrapped at the level of PIP joint, causing flexion contracture of the PIP joint

POSTERIOR INTEROSSEOUS NERVE SYNDROME
• There is lack of extension of the fingers and the finger may have a flexed posture