Mallet finger

mallet finger

1. Mallet finger Dr. Santosh Batajoo

2. Introduction Deformity of the finger caused by damaged extensor tendon distal to DIP. Also called baseball finger or hammer finger or drop finger. Disruption may be bony or tendinous . Injury at zone 1.

3. Common in young to middle-aged males and older females. Most frequently involves long, ring and small fingers of dominant hand.

4. Mechanism Ball or the object strikes the tip of the finger or thumb and forcibly bends it. A minor force such as tucking in a bed sheet. Force tears the tendon or even pull away a piece of bone.

5. Less common mechanism is a sharp or crushing-type laceration to the dorsal DIP joint. Less commonly, a forceful hyperextension injury of the DIP joint.

6. Classification (Doyle’s) Type I Closed injury with or without small dorsal avulsion fracture Type II Open injury (laceration) Type III Open injury ( deep soft tissue abrasion involving loss skin and tendon substance) Type IV Mallet fracture A - distal phalanx physeal injury (pediatrics) B - fracture fragment involving 20% to 50% of articular surface (adult) C - fracture fragment >50% of articular surface (adult)

7. Signs & symptoms The fingertip droops. The patient cannot straighten but passive movement is normal. Finger may be painful, swollen and bruised. Lack of active DIP extension. Swan-neck deformity

8. Diagnosis X-ray : Avulsion of distal phalanx May be a ligamentous injury with normal bony anatomy.

9. Treatment NONSURGICAL: Goal – to keep the fingertip straight until the tendon heals. Extension splints with DIP joint in extension for 6-8 weeks then at night for a 4 additional weeks. Bone avulsion – mallet splint for 6 weeks

10. Maintain free movement of the PIP joint. Begin progressive flexion exercise at 6 weeks.

11. Surgical : Indications- volar subluxation of distal phalanx, large bone fragments with >50% articular suface involved, non-surgical treatment was not successful. >2mm articular gap

12. CRPP or ORIF – pin fixation or dorsal/extension blocking pin. ORIF with a pull-out wire. Surgical reconstruction of terminal tendon in chronic injury > 12 weeks with healthy joint – direct repair, tenodermodesis or retinacular ligament reconstruction Central slip release (Fowler)

13. Type 1 and type 2 can be treated closed. Type 3 require soft tissue coverage and pinning of the DIP joint. DIP arthrodesis – painful, stiff, arthritic DIP joint Swan neck deformity – lateral band tenodesis , FDS tenodisis , Fowler central slip tenotomy

14. Complications Extensor lag Non union Swan neck deformities due to – attenuation of volar plate and transverse retinacular ligament at PIP joint, dorsal subluxation of lateral bands, hyperextension of PIP, contracture of traiangular ligament.

15. Thank you…