1. Injuries To The Hand And Digits
Chrisnel Jean, D.O.
May 30, 2006
Reviewed by Dr. Batizy

2. Outline Anatomy Principles of Evaluation Tendon Injuries
General Hand Examination
Anesthesia and Direct Wound Examination
Radiographs, Consultation, and Disposition
Tendon Injuries
Flexor / Extensor Tendons
Ligaments And Dislocation Injuries
Compartment Syndrome
High-Pressure Injection Injury

3. Hand Anatomy Hand consist of 27 bones: 14 Phalangeal bones
5 Metacarpal bones
8 Carpal bones
Carpal bones are made up of two rows of four bones bridged by flexor retinaculum which forms the carpal tunnel.
Carpal tunnel consist of the median nerve and the nine long flexor of the fingers

4. Hand Anatomy Intrinsic muscle of the hand:
Have their origins and insertions within the hand.
Consist the following:
Thenar, Hypothenar, adductor pollicies, the interossei and the lumbricals. (Refer to pg 1665 for anatomical description)

5. Hand Anatomy Extensor Tendons:
Courses over the dorsal side of the forearm, wrist and hand.
9 extensor tendons pass under the extensor retinaculum and separate into 6 compartments

6. Surface anatomy of the hand.
The tendons that are palpated with thumb abducted and extended form an anatomic snuff-box.

7. Hand Anatomy Extensor Tendons:
The extensor tendons gain entrance to the hand from the forearm through a series of six canals, five fibroosseous and one fibrous The communis tendons are joined distally near the MP joints by fibrous interconnections called juncturae tendinum. Beneath the retinaculum, the extensor tendons are covered with a synovial sheath.

8. Hand Anatomy Extensors digitorum communis are connected by junctura.
Because of this, a complete tendon laceration proximal to the junction may still result in normal extensor fuction.

9. Hand Anatomy Flexor Tendons:
Courses over the volar side of the forearm, wrist, and hand.
Unlike the extensor tendons, the flexor tendons are enclosed in synovial sheaths making them prone to deep space infections.

10. Hand Anatomy Flexor Tendons:
Flexor carpi radialis, flexor carpi ulnaris, and palmaris longus primarily flex the wrist

11. Hand Anatomy

12. Hand Anatomy 9 flexor tendons pass through the carpel tunnel:
1 tendon go to the base of the dist. Phalanx of the thumb
The other 4 digit has 2 tendon each (FDS / FDP).

13. Hand Anatomy
Flexor digitorum superficialis (FDS) insert into middle phalanx.
Flexor digitorum profundus (FDP) runs deep to the FDS until the level of the MP joint where FDS bifurcates.
FDP inserts at the base of the distal phalanx and acts primarily to flex the DIP joint as well as all other joints flexed by FDS. (Figure 268-5).

14. Hand Anatomy Blood supply (BS):
Hand and digits has dual (BS) with contributions from the radial and ulnar arteries.

15. Hand Anatomy Blood supply (BS):
Proximal portions of the hand (BS) come from the deep and superficial arches on the palmar and dorsal side.
BS of the fingers is distributed by the digital arteries that arises from the superficial palmer arch.

16. Hand Anatomy - Blood supply
The Allen's test.

17. Hand Anatomy
The cutaneous nerve supply in the hand. M, median; R, radial; U, ulnar; PCM, palmar cutaneous branch of median nerve; DCU, dorsal cutaneous branch of ulnar nerve

18. Principles of Evaluation
History:
Should include the time, the cause of the injury and eval for the possibility of crush, burn, or chemical exposure.
The patient’s occupation, prior hand injuries, and handedness should be documented

19. Principles of Evaluation
The position of the hand at the time of injury should be determined.
Injuries with the digits in flexion may result in retraction of the cut end of the tendon when the digit is examined in neutral position.

20. Principles of Evaluation
Physical Exam
Should detail the extent of injury by documenting the following:
Amount of devascularization
Status of the skin
Posture of the fingers
Presence of deformity
Active bleeding
B/L grip strength

21. Principles of Evaluation
Physical Exam
ROM and strength should be tested against resistance.
Nerve testing:
Test median nerve:
Have the pt flex the distal phalanx of the thumb against resistance
Test opposition by touching the tip of the thumb to the tip of the little finger
The pt will be unable to oppose against resistence if median nerve function is lost.

22. Principles of Evaluation
Nerve testing
Test median nerve:
Test thumb abduction by placing the hand palm up and raising the thumb to the perpendicular while palpating the belly of the abductor pollicis muscle to insure it is contracting.

23. Principles of Evaluation
Nerve testing:
To test ulnar nerve
Spread the fingers apart against resistance and then push them together against resistance.
Test the hypothenar muscle, extend the fingers and then move the fifth finger away from the others
Test thumb adduction (ulnar nerve innervates the adductor pollicis muscles) bring the thumb tightly against the side of the index finger.

24. Principles of Evaluation
Nerve testing:
To test ulnar nerve
Adductor strength can be further tested by interposing a piece of paper between the thumb and the side of the index finger and then trying to pull the paper away.
To test radial nerve:
Extend the fingers and wrist.
With the thumb in the hitchhiking position, test its resistance to further extension.

25. Principles of Evaluation
Nerve testing: Sensation
Determined by 2-point discrimination.
Normal 2-point discrimination is <6 mm at the fingertips and is often <2 mm. Both injured and non-injured fingers must be compared.
Repeat 2-point discrimination testing 2 – 4 times on each side of the digit (80% accuracy is considered acceptable)

26. Principles of Evaluation
Nerve testing: Sensation
A sensory deficit implies a potential digital artery laceration because of the close proximity of the two.
Tendon testing:
Full ROM of each tendon against resistance should be assessed and compared with the uninjured side.

27. Principles of Evaluation
Tendon testing:
Important to test resistance because up to 90 % of a tendon can be lacerated with preservation of ROM without resistance.
Pain along the course of the tendon during resistance testing suggests a partial laceration even if the strength appears adequate.

28. Principles of Evaluation
Tendon testing:
FDP is tested by flexing the DIP against resistance while the MP and PIP are held in extension.
FDS is tested by flexing the PIP against resistance while the remaining fingers are held.

29. Principles of Evaluation
FDP is tested
To test for an intact profundus tendon, the examiner maintains the digit in extension while the patient attempts to flex the terminal phalanx.

30. Principles of Evaluation
FDS is tested
Examination to assess function of flexor digitorum superficialis.

31. Principles of Evaluation
Anesthesia and Direct Wound Examination:
Sensation and ROM should be tested before anesthesia applied.
Exam should be done under a bloodless field by applying local tourniquet or penrose drain around the base of the finger.

32. Principles of Evaluation
Radiographs, Consultation, and Disposition:
XRAY: should include a PA, lateral , and oblique view.
Injuries requiring immediate and delayed follow-up by a hand surgeon are listed in Tables and
Guidelines for adequate immobilization and follow-up for specific hand injuries are listed in Tables 268-3

33. Principles of Evaluation
Tendon injuries: Flexor tendons
Most common cause of flexor tendon injury is a laceration.
A distal to proximal five zone (I – V) classification system for flexor tendon injuries has been developed based on location, treatment considerations, and prognosis.
Refer to pg 1670 for specific descriptions.

34. Principles of Evaluation
Tendon injuries: Extensor tendons
Are the most common site of tendon injuries because of the superficial nature of the tendons on the dorsum of the hand.
A separate zone classification system (I – VIII) has been developed for assessing injury patterns, repair techniques, and rehabilitation.
Refer to pages 1670 – 1671 for specific description.

35. Ligament and Dislocation injuries
DIP
Dislocation at DIP are uncommon because of the firm attachments of the skin and subq tissue to the underlying bone.
Dislocations at the DIP are usually dorsal.
Reduction can be done by longitudinal traction and hyperextension, followed by direct dorsal pressure to the base of the distal phalanx after a digital block.

36. Ligament and Dislocation injuries
Dorsal dislocation at the DIP jt without associated fracture
Volar dislocation of DIP joint of little finger.

37. Ligament and Dislocation injuries
PIP Dislocation:
One of the most common ligamentous injuries
Mechanism:
Usually due to axial load and hyperextension.
Dorsal dislocation occurs when the volar plate ruptures.
Lateral dislocation occurs when one of the collateral ligaments ruptures with at least a partial avulsion of the volar plate form the middle phalanx.
Volar dislocations are rare.

38. Ligament and Dislocation injuries
Lateral dislocation of middle finger PIP joint.

39. Ligament and Dislocation injuries
PIP Dislocation:
Reduction
Perform similarly to DIP dorsal dislocations
Active ROM and strength should be tested after reduction.
If testing is normal, then splint in 30-degree flexion for 3 wks.
If the joint is irreducible or there is evidence of complete ligamentous disruption, operative repair is required.

40. Ligament and Dislocation injuries
MP dislocation:
Less common than at the PIP jt
Mechanism:
Usually due to hyperextension forces that rupture the volar plate causing dorsal dislocation.
In subluxation (simple dislocation) – the jt appears to be hyperextended 60 – 90 degrees and the articular surfaces are still in contact.
Volar dislocation are rare and usually require operative reduction.

41. Ligament and Dislocation injuries
MP dislocation:
Reduction:
Does not involve hyperextension (this might convert it from a simple to a complex dislocation)
Performed with the wrist flexed to relaxed the flexor tendon and applying pressure over the dorsum of the proximal phalanx in a distal and volar direction.
Splint the MP jt in flexion after reduction.

42. Ligament and Dislocation injuries
CMC jt dislocation:
Are uncommon because the jt is supported by strong dorsal, volar, and interosseous ligaments and reinforced by the broad insertions of the wrist flexions and extensors.

43. Ligament and Dislocation injuries
CMC jt dislocation:
Mechanism:
Usually due to high-speed mechanisms (MVC, falls, crushes, or clenched fist trauma).
Usually occurs via dorsal and with associated fractures.

44. Ligament and Dislocation injuries
CMC jt dislocation:
Reduction:
Attempt after regional anesthesia with traction and flexion with simultaneous longitudinal pressure on the metacarpal base.
Pt need early referral after reduction to determine if further fixation is needed.

45. Ligament and Dislocation injuries
Thumb IP dislocation
Are rare but, if present, usually open.
Mechanism:
Usually hyperextension with rupture of the volar plate.
Reduction:
Similar to the IP jt of the other digits
Immobilized for 3wks in mild flexion.

46. Ligament and Dislocation injuries
Thumb MP dislocation:
Usually dorsal
Can be simple (subluxation) or complex
Mechanism:
Hyperextension force causing rupture of the volar plate.

47. Ligament and Dislocation injuries
Thumb MP dislocation:
Reduction:
After a radial nerve block.
Performed with pressure directed distally on the base of the proximal phalanx with the metacarpal flexed and abducted.

48. Ligament and Dislocation injuries
Thumb MP Collateral Ligament Rupture:
Rupture of the ulnar collateral ligament (gamekeeper’s thumb, skier’s thumb)
Occurs when the mechanism causes radial deviation (abduction) of the MP jt.
Tear usually occur at the insertion into the proximal phalanx.
Significant injury occurs to the dorsal capsule and volar plate.

49. Ligament and Dislocation injuries
Thumb MP Collateral Ligament Rupture:
Rupture of the ulnar collateral ligament (gamekeeper’s thumb, skier’s thumb)
Type 1 Avulsion fracture, nondisplaced
Type 2 Avulsion fracture, displaced
Type 3 Torn ligament, stable in flexion
Type 4 Torn ligament, unstable in flexion

50. Ligament and Dislocation injuries
Gamekeeper's thumb. (1.) The normal thumb MCP jt ulnar collateral ligament. (2.)Tear in the extensor mechanism overlying the disrupted ligament acts as a buttonhole and (3.) traps the ligament end. In this position, spontaneous healing and recovery of stability is prevented. 

51. Ligament and Dislocation injuries
Thumb MP Collateral Ligament Rupture:
Rupture of the ulnar collateral ligament
Hand surgery referral is recommended for all patients with weakness of pincer function and point tenderness at the volar – ulnar aspect of the thumb MCP jt resulting from a forced abduction mechanism of injury.

52. Ligament and Dislocation injuries
Thumb MP Collateral Ligament Rupture:
Rupture of the ulnar collateral ligament
If XRAY negative for fracture, then abduction stress testing of the ulnar collateral ligament maybe performed for added information.
Test the thumb MCP both in full extension and 30-degree flexion, by stabilizing the metacarpal with one hand while applying lateral (radial) stress on the proximal phalanx with the other.

53. Ligament and Dislocation injuries
Thumb MP Collateral Ligament Rupture:
Rupture of the ulnar collateral ligament
More than 40 degrees radial angulation indicates complete rupture and requires surgical consultation.
Repair best accomplished in 1 wk.
Rupture of the radial collateral ligament
Not as common
Mechanism is forced adduction

54. Ligament and Dislocation injuries
Thumb CMC:
Isolated dislocation is rare compared to the more common Bennett fracture dislocation.
Easy to reduce but unstable after reduction.
Apply thumb spica splint after reduction.
Need surgical referral.

55. ROM of the Thumb

56. Fractures Distal Phalanx:
Account for 15 – 30 present of all hand fractures.
Are usually from crush or shearing forces.
Can be classified as tuft, shaft, or intraarticular.
Tuft fractures – can be associated with nail bed lacerations

57. Fractures Distal Phalanx:
Fractures at the base may be associated with flexor or extensor tendon involvement.
These fractures are treated as soft tissue injuries with protective splinting.

58. Fractures Proximal and Middle Phalanx Proximal phalanx
Has no tendinous attachments
Fractures frequently have volar angulation from the forces of the extensor and interosseous muscles.

59. Fractures Proximal and Middle Phalanx Middle Phalanx:
Has the FDS insert on the entire volar surface and the extensor tendon insert at the proximal base
Fractures at the base have dorsal angulation and fractures at the neck result in volar angulation.
Most often these fractures are stable and nondisplaced.
Can be treated with early protected motion by buddy taping.

60. Fractures Proximal and Middle Phalanx
Unstable fractures amenable to closed reduction can be splinted from the elbow to the DIP with the wrist at 20-degree extension and the MP jt in 90-degree flexion.
Midshaft transverse fractures, spiral fractures and intraarticular fractures often require internal fixation.

61. Fractures Metacarpal (II to V) Fractures
2nd and 3rd metacarpals are relatively immobile and fractures require anatomic reduction.
4th and 5th MC have 15 to 20-degree AP motion, which allows for some compensation.
MC fractures are categorized as head, neck, shaft, or base fractures.

62. Fractures Metacarpal (II to V) Fractures Head:
Usually caused by a direct blow, crush or missile.
Fractures are distal to the insertion of the collateral ligaments and are often comminuted.
If a laceration is present a human bite must be considered.
Treatment:
Ice, elevation, immobilization, and referral to a hand surgeon.

63. Fractures Metacarpal (II to V) Fractures Neck:
Usually caused by a directed impaction force.
Fracture of the fifth MC neck is often referred to as a boxer’s fracture
Fracture are usually unstable with volar angulation.
Angulation of < 20 degrees in the 4th and 40 degrees in the 5th MC will not result in functional impairment

64. Fractures Metacarpal (II to V) Fractures Neck:
If greater angulation in these MC occur, reduction should be attempted
Fractures should be splinted with the wrist in 20-degree extension and the MP flexed at 90 degrees.
In the 2nd and 3rd MC, angulation of <15 degrees is acceptable. If significantly displaced or angulated then anatomic reduction and surgical fixation is needed

65. Fractures Metacarpal (II to V) Fractures Shaft:
Usually occur via a direct blow
Rotational deformity and shortening are more often in shaft fractures than in neck fractures.
If reduction is needed, than operative fixation is usually indicated.

66. Fractures Metacarpal (II to V) Fractures Base
Usually caused by a direct blow or axial force.
They are often associated with carpal bone fractures.
Fractures at the base of the 4th and 5th MC can result in paralysis of the motor branch of the ulnar nerve.

67. Fractures
Thumb MC
Because of the mobility of the thumb MC, shaft fractures are uncommon
Fractures usually involve the base.
Two type:
Extraarticular
Intraarticular

68. Fractures Thumb MC Extraarticular:
Are caused by a direct blow or impaction mechanism.
Mobility of the CMC jt can allow for 20-degree angular deformity. Angulation greater than this requires reduction and thumb spica splint for 4 wks.
Spiral fractures often require fixation.

69. Fractures Thumb MC Intraarticular
Caused by impaction from striking a fixed object (two type)
Bennett fx
Is an intraarticular fx with associated subluxation or dislocation at the CMC jt.
The ulnar portion of the MC usually remains in place.
The distal portion usually subluxes radially and dorsally from the pull of abduction pollicis longus and the adductor pollicis
Treatment – thumb spica and referral

70. Fractures Bennett's fracture
Avulsion fracture of the articular surface of the first metacarpal with subluxation at the CMC jt.

71. Fractures Thumb MC Intraarticular Rolando fracture
An intraarticular comminuted fracture at the base of the metacarpal.
Mechanism of injury is similar to the Bennett fracture, but less common.
Treatment – thumb spica splint and surgery consultation.

72. COMPARTMENT SYNDROME
May occur in crush injury of the hand with or without associated fracture.
Involved compartments of the hand includes:
Thenar
Hypothenar
Adductor pollicis
Four interossei

73. COMPARTMENT SYNDROME
Cross section through the palm showing compartments of the hand

74. COMPARTMENT SYNDROME
Edema of tissues or hemorrhage within any of these compartments may lead to elevated pressures that result in tissue necrosis and subsequent loss of hand function due to contracture.
Sign and symptoms:
Pain and paresthesias occur early
Paralysis and pulselessness occurring later

75. COMPARTMENT SYNDROME Sign and symptoms: PE findings: Pain
Most consistent clinical sign
usually described as deep, constant, poorly localized and disproportionate to clinical findings.
PE findings:
“intrinsic minus” position at rest (MCP extended with PIP slightly flexed)
Pain with passive stretch of the involved compartmental muscle

76. COMPARTMENT SYNDROME PE findings:
Pain with passive stretch of the involved compartmental muscle
Interosseous: performed with MCP extended and PIP fully flexed with slight radial ulnar deviation
Thenar / Hypothenar: performed by extension of MCP
Tense swelling of the affected compartment

77. COMPARTMENT SYNDROME Diagnosis
Confirmed by compartment pressure measurement – high rate of false readings.
In the setting of severe crush injury with signs and symptoms suggestive of compartment syndrome, emergent hand surgeon consultation for fasciotomy is mandatory.

78. High – Pressure Injection Injury
The initial dissipation of kinetic energy through the soft tissue of the hand produce tissue edema and resultant ischemia of the tissue.
Most common injected substances include grease, paint, hydraulic fluid, diesel fuel, paint thinner, and water.

79. High – Pressure Injection Injury
Definitive treatment of high – pressure injection injuries is early surgical decompression and debridement of injected areas.
These must be recognized as surgical emergency and obtain immediate hand surgery consultation, immobilize and elevate the affected hand, initiate tetanus prophylaxis, broad-spectrum antibiotics and provide adequate analgesia.