1. Injuries to the Hand and Digits Tintinalli Chapter 268

2. Hand/Digit Anatomy

3. Anatomy • Extensor tendons (9) • Dorsal side of forearm, wrist and hand • Pass under extensor retinaculum • Connected by junctura  complete tendon lac my still result in normal extensor function • Flexor tendons (9) • Volar side of forearm, wrist and hand • Pass under flexor retinaculum • 4 flexor digitorum superficialis (FDS)  middle phalanx • 4 (FDP) profundus  distal phalanx

4. Blood Supply • Dual • Radial artery  deep arch • Supply palm, thumb, and part of index finger • Ulnar artery  superficial arch • Give rise to common digital arteries • Supply palm, 2nd through 5th digits

5. Ulnar Nerve • Runs deep to the carpi ulnaris tendon. • Sensation: • palm and dorsal aspects of the ulnar side of hand, 5th digit and ulnar half of the 4th digit. • Motor: • Dorsal interosseous, hypothenar muscles, ulnar lumbricals • Test • abduction of fingers against resistance

6. Median nerve • Runs through carpal tunnel • Sensory: • Thumb, palm on the radial side of the hand, the palmar aspect of the radial 2 ½ fingers, the dorsal aspect of the tips of the index and middle fingers and radial half of the ring finger. • Motor: • Thenar muscles, radial lumbricals • Test: • opposition of the thumb to each finger vs resistance -watch for thenar muscles contractions

7. Radial nerve • Sensory • dorsum of radial aspect of the hand, dorsum of thumb, dorsal aspect of the 2nd and 3rd fingers, dorsal radial half of the 4th finger. • Motor • Extensors of wrist, no intrinsic muscles in hand • Test • extension of the wrist and fingers against resistance • Loss of function: wrist drop

8. Evaluation • History • Time and cause of injury • Occupation, prior hand injury, handedness • PE • Posture, status of skin, devascularization, deformity, active bleeding, grip strength • Compare to other hand • Clenched fist: observe orientation if middle/distal phalanxes (should be parallel)

9. Evaluation • Sensory Testing • Two point discrimination • >6mm fingertips abnormal • Sensory deficit implies digital artery lac (close prox) • Tendon Testing • Full ROM vs resistance compared to uninjured side • Pain along course of tendon suggests partial lac • FDP: flex DIP while PIP/MP held extended • FDS: flex PIP while fingers held extended • Radiographs • PA, lateral, oblique

10. Hand Surgery Consultation • Immediate: • vascular injury, irreducible dislocations, contaminated wounds, crush, compartment syndrome, high pressure injection, hand or finger amputation • Delayed: • Extensor/flexor tendon laceration, FDP rupture, nerve injury, fractures, dislocations, unstable ligament injury

11. Anesthesia • Regional nerve blocks-useful with finger/hand injuries. • Finger injuries-digital block better than local • Sensation is by the palmar and dorsal digital nerves along the lateral aspect of each finger. • Digital block • Dorsal approach • Palmar approach • Web space approach

12. Flexor Tendon Injuries • Most common: laceration • Zone I – Zone V • Flexor tendon injuries-repaired by hand surgeon in 12 hours

13. Extensor Tendon Injury • Most common site of tendon injury: superficial on dorsum of hand • Mallet Finger: common injury in athletes • MOI: blunt trauma, sudden forced flexion • Unable to extend DIP • Swan-neck deformity develops in chronic/untreated • Tx • No fx: Splint in slight hyperextension • Fx: ortho for pinning

14. Extensor Tendon Injury • Boutonniere Deformity • Complete disruption of central tendon • Flexion of PIP and hyperextension of DIP • MOI direct blow • Tx • splint the PIP in extension refer to ortho

15. Ligament and Dislocation Injury • DIP (uncommon) • Longitudinal traction and hyperextension, direct dorsal pressure base of distal phalanx • PIP (most common) • Reduce as above plus splint 30 degree flexion • MP • Wrist flexed with pressure applied over dorsum of the proximal phalanx in a distal and volar direction • Thumb MP Collateral Ligament Rupture • Game keepers/Skiers Thumb: radial deviation of MP • Hand surgery referral recommended with weak pincer

16. Fractures • Distal Phalanx (15-30% of hand fx) • Splint • Proximal and Middle Phalanx • Buddy taping

17. Fractures • Metacarpal: MOI - punch clenched fist • Head • Direct blow, crush, missile • Laceration- assume human bite • Neck • Direct impaction of force • Reduce if: • >15 degree angulation 2nd and 3rd • >20 degree angulation 4th • >40 degree in 5th (Boxer’s fx) • Shaft • Direct blow • Rotational deformity/shortening likely • Tx: operative

18. Compartment Syndrome • Crush injury • Involved compartments: • Thenar, hypothenar, adductor pollicis, 4 interossei • Edema/hemorrhage  increased pressure  tissue necrosis  loss of hand fxn/contracture • Pain (disproportionate and on passive stretch), paresthesia, paralysis, pulselessness • Tx: Hand consult for fasciotomy

19. High pressure injection injury • Initially appear benign: HISTORY important • Injection into soft tissue (2000-10,000) psi • Industrial/operator • Grease, paint, hydraulic fluid, diesel fuel, etc. • Causes inflammatory response, tissue edema/ischemia • Compartment syndrome • Xray: • radio-opaque substance, subQ air • Tx: • Hand consult, immobilize, elevate, tetanus, atb, analgesics • Surgical decompression/debridement

20. High Pressure Injection

21. DeQuervain’s tenosynovitis • Inflammed extensor tendons of the thumb-pain on radial aspect of wrist-worse with use • Finkelstein test-pain on ulnar deviation of the wrist while thumb is flexed and held in the palm by the other finger • Treatment-NSAID’s-splint position of function

22. Infections of the Hand • Paronychia • nail fold infection-Staph & Strep-Treat with I&D • Felon • fingertip infection-Staph-Treat with I&D • Incision through the pulp of the finger laterally with wick placed though the incision-remove in 72 hours

23. Infections of the Hand • Herpetic Whitlow- • viral infection of distal finger-HVS I or II-pain, burn, itching and herpetic lesions then form. • Treatment-splint and analgesics-may give oral antivirals • DO NOT DRAIN

24. Infections of the Hand • Human bite or fight bite • punch to the mouth usually • DO NOT suture over the MCP-heal by secondary intention • Eikenella corrodens • Treatment-ortho consult, xrays, wound cultures, irrigate, IV antibiotics if necessary

25. Infections of the Hand • Tenosynovitis • Typically from punture wound-staph or strep • Diagnose-Kanavel four cardinal signs • Held in slight flexion • Symmetric swelling of the finger • Tender along flexor tendon sheath • Pain with passive extension of the finger • Tx: IV antibiotics, culture, tetanus • Penetrating trauma penicillinase-resistant antistaphylococcal PCN or 1st gen. cephalosporin • No history of trauma in a sexually active adult, consider GC-treat with ceftriaxone