Basics
Tendons near lacerations must be explored through complete range of motion to rule out injury. é á
Description
- Based on mechanism
- External trauma:
- Penetrating trauma:
- Gunshot wounds
- Glass
- Knives
- Foreign bodies
- Blunt trauma:
- Crushing force or avulsion from hyperextension of a joint
- Internal trauma:
- Entrapment/laceration from bony fracture (rare)
Etiology
Tendon injuries grossly categorized into those affecting upper vs. lower extremities: é á
- Upper-extremity injuries frequently related to the workplace, home, an assault, or attempted suicide
- Lower-extremity injuries most often associated with work or motor vehicle accident
Diagnosis
Signs and Symptoms
- Pain is the cardinal symptom.
- Functional deficit
- Soft tissue damage:
- Swelling
- Ecchymosis
- Lacerations
- Hemorrhage
- Abnormal resting position of the extremity or large joint instability increases suspicion for tendon injury.
Essential Workup
- A careful history:
- Mechanism, time of injury
- Hand position during injury
- Hand dominance
- Drug allergies
- Medications
- Past medical history
- Tetanus vaccination status
- Physical exam:
- Examine resting position of hand. (At rest there is natural flexion of fingers increasing from radial to ulnar side.)
- Examine the wound in position of initial injury.
- Perform neurovascular exam before local anesthesia is instilled.
- Examine each digit separately.
- Test strength against resistance.
- Examine tendon with direct visualization through full range of motion.
- Flexor digitorum profundus injuries:
- Present with inability to flex the distal interphalangeal (IP) joint
- Exam involves stabilizing the proximal IP joint in full extension while the patient attempts to flex distal IP joint.
- Flexor digitorum superficialis injuries:
- Present with inability to flex the proximal IP joint of a digit
- Usually established by means of standard superficialis tendon test:
- While holding the uninjured digits in full extension, the patient attempts to flex the affected finger at the proximal IP joint.
- False negative if profundus is functional.
- The distal IP joint extension test:
- May make this diagnosis more apparent
- Patient is asked to make a precision pinch between thumb and the injured finger.
- Then asked to flex the proximal IP joint so that the distal IP joint is hyperextended
- Confirms the integrity of the flexor digitorum superficialis
- Forearm and wrist flexor injuries:
- Present with inability to flex ulnar or radial side of wrist or to flex the wrist while opposing the thumb to the little finger
- Extensor tendon injuries:
- Found by weakness or lack of extension of the distal phalanx against resistant
- Indicates partial or complete disruption
- Best determined with patient placing palm on flat surface and asking the patient to attempt to extend the fingers individually
- Palpate each tendon.
- Loss of normal tension indicates injury.
- Further explore tendons and wounds after local anesthesia (1% lidocaine or 0.5% bupivacaine) in a bloodless, well-lit surgical field:
- Tendons near lacerations must be explored through complete range of motion.
- Best elucidates tendon injuries distal or proximal to a skin wound
- More difficult to get an adequate exam
- The healing process is usually quicker and more often associated with complete return to preinjury function.
Diagnosis Tests & Interpretation
Lab
Wounds 1st examined >12 hr after injury or wounds with evident infection should be cultured. é á
Imaging
- Radiographs are frequently needed to identify radiopaque foreign bodies or fractures.
- High-frequency US can be used to identify complete tendon lacerations:
- Partial tendon lacerations difficult to image
- A water bath may help when attempting to image a painful extremity.
- US guidance may help to guide removal of foreign bodies.
- MRI
Differential Diagnosis
- Always rule out an associated foreign body or fracture.
- Lacerations over the proximal IP joint may involve the lateral bands or the central slip of the extensor mechanism:
- Boutonni â Ęre deformity from improper repair
- Disruption of the extensor tendon distal to the central slip results in a mallet finger deformity.
- "Jersey finger " Ł is a closed traumatic injury with avulsion of the flexor digitorum profundus, seen when a football player grabs the jersey of another player and his finger gets stuck.
- Avulsion of the flexor digitorum superficialis distally may be present with or without an associated avulsion fracture:
- Suspect when a grasping finger is hit by a fast-moving object (jammed finger).
Treatment
Pre-Hospital
- Do not remove foreign matter from the patient in the field.
- Immobilize and transport patient.
- Apply direct pressure to control hemorrhage.
- Assess distal neurovascular status for signs of compromise.
- Contact medical control before any attempted reduction.
Initial Stabilization/Therapy
- Evaluate extremity and control hemorrhage with direct pressure.
- Remove all jewelry or constricting bands.
Ed Treatment/Procedures
- Pain control as required
- Administer tetanus toxoid as needed.
- Copious irrigation with 1 L NS
- Broad-spectrum antibiotic, such as a 1st-generation cephalosporin (Cefazolin)
- Tendon lacerations associated with human bites:
- Must be copiously irrigated
- Place on IV antibiotics with coverage of oral anaerobes (ampicillin/sulbactam).
- Immobilize and elevate the hand.
- Remove all foreign bodies and provide debridement of avascular tissue.
- Partial tendon lacerations that involve >20% of the cross-sectional area of the tendon must be repaired.
- Simple extensor tendon lacerations may be repaired in the ED:
- Use a 4-0 or 5-0 nonabsorbable suture in a figure-of-8 or a modified Kessler stitch.
- All suspected flexor tendon, wrist, and distal forearm tendon lacerations require consultation by a hand surgeon, ideally within 12 hr.
- Tendon lacerations over the proximal IP joint may result in a boutonni â Ęre deformity:
- The superficial nature of multiple tendons, nerves, and vessels on the volar aspect of the wrist renders them easily vulnerable to penetrating trauma:
- "Spaghetti wrist " Ł or "full house " Ł:
- Volar wrist laceration with at least 10 structures involved
- Requires prompt consultation with a hand surgeon
- Tendon lacerations associated with fractures require referral for operative repair.
- If a surgeon is not promptly available:
- Irrigate copiously.
- Close skin without repair of tendon.
- Immobilize injured hand with a bulky volar dressing and splint.
- Wrist in 20 " ô30 é ░ of flexion
- Metacarpal joint in 60 " ô70 é ░ of flexion
- IP joints in 10 " ô15 é ░ of flexion
Medication
- Ampicillin/sulbactam: 3 g IV q6 (peds: 200 mg/kg/d IM or IV div. q6h)
- Cefazolin: 1 g IV piggyback (peds: 100 mg/kg/d IM or IV div. q6h, followed by 40 mg/kg/d PO QID for 5 " ô7 days)
- Tetanus toxoid: 0.5 mL IM (peds: <7 yr " ôdiphtheria " ôpertussis " ôtetanus vaccine preferred; in those >7 yr, adult dose tetanus toxoid if immunization series not completed), tetanus immune globulin, as required, 250 IU administered IM
Follow-Up
Disposition
Admission Criteria
- Patients with infected tendon lacerations must be admitted for operative debridement.
- Any patients with tendon injury secondary to human bite must be admitted for operative debridement and IV antibiotics.
- Any patients with significant flexor tendon laceration may be admitted for timely operative repair or transferred to the nearest hand surgeon.
Discharge Criteria
- Patients with an extensor tendon laceration that is not infected, nor associated with other significant injury or underlying fracture, which was repaired by the ED physician and is now properly splinted, may be discharged with timely surgical follow-up.
- Patients with an extensor tendon laceration requiring surgeon referral for repair (wrist, forearm, proximal IP joint), which has been properly treated and splinted, with the patient placed on antibiotics, may be discharged for timely surgical follow-up.
Pearls and Pitfalls
- Partial lacerations are common but more difficult to diagnosis than complete disruptions because they may demonstrate intact function:
- Alterations of the normal resting hand position may indicate partial laceration.
- Lacerations over the metacarpophalangeal joint should be considered the result of a human bite until proven otherwise:
- Look for associated extensor tendon injury while metacarpophalangeal joint flexed.
- It is very important to test strength because tendon injuries with up to a 90% full-thickness laceration can have normal range of motion. Therefore, test strength against resistance.
- Tendon laceration with >20% cross-sectional area of involvement need repair
Additional Reading
- Fitoussi é áF, Badina é áA, Ilhareborde é áB, et al. Extensor tendon injuries in children. J Pediatr Orthop. 2007;27(8):863 " ô866.
- Matzon é áJL, Bozentka é áDJ. Extensor tendon injuries. J Hand Surg Am. 2010;35(5):854 " ô861.
- Nassab é áR, Kok é áK, Constantinides é áJ, et al. The diagnostic accuracy of clinical examination in hand lacerations. Int J Surg. 2007;5(2):105 " ô108.
- Sokolove é áPE. Extensor and flexor tendon injuries in the hand, wrist, and foot. In: Roberts é áJR, Hedges é áJR, eds. Clinical Procedures in Emergency Medicine. 5th ed. Philadelphia, PA: Saunders Elsevier; 2009.
- Wu é áTS, Roque é áPJ, Green é áJ, et al. Bedside ultrasound evaluation of tendon injuries. Am J Emerg Med. 2012;30(8):1617 " ô1621.
Codes
ICD9
- 848.9 Unspecified site of sprain and strain
- 884.2 Multiple and unspecified open wound of upper limb, with tendon involvement
- 891.2 Open wound of knee, leg [except thigh], and ankle, with tendon involvement
- 883.2 Open wound of finger(s), with tendon involvement
ICD10
- S46.929A Laceration of unspecified muscle, fascia and tendon at shoulder and upper arm level, unspecified arm, initial encounter
- S56.429A Laceration of extensor muscle, fascia and tendon of unspecified finger at forearm level, initial encounter
- S86.909A Unspecified injury of unspecified muscle(s) and tendon(s) at lower leg level, unspecified leg, initial encounter
- S66.329A Lacerat extn musc/fasc/tend unsp finger at wrs/hnd lv, init
- S56.129A Laceration of flexor muscle, fascia and tendon of unspecified finger at forearm level, initial encounter
- S66.929A Lacerat unsp musc/fasc/tend at wrs/hnd lv, unsp hand, init
SNOMED
- 301453009 tendon laceration (disorder)
- 275458004 Open wound of arm with tendon injury (disorder)
- 269181003 Open wound of knee, leg and ankle with tendon involvement (disorder)
- 446313009 Laceration of tendon of finger (disorder)