Soft Tissue Hand Injury

Back

Background

Hand injuries are common and account for 5-10% of emergency department (ED) visits nationwide. The complexity of the hand and the similarities in clinical presentation of different injuries make understanding of hand anatomy and function, good physical examination skills, and knowledge of indications for treatment indispensable for the emergency physician.

Terminology

Thorough knowledge of the anatomy and functions of the hand is required for proper diagnosis and treatment. Use of proper terminology prevents confusion that may compromise the care of patients with hand injuries. The following is a brief review of standard terminology and key anatomic structures.

Motion and position: Standard terminology also applies to motions and positions of the hand and digits.

Anatomy

Surface anatomy: Three creases are present on the palmar surface of the digits. The distal and middle palmar creases correspond to the distal interphalangeal (DIP) and proximal interphalangeal (PIP) joints, respectively. The proximal digital palmar crease does not overlie a joint as the MCP is more proximal. The long thenar crease partially encircles the thenar eminence and overlies the metacarpophalangeal (MCP) joint.

Bony anatomy: The wrist is composed of 8 carpal bones arranged in 2 rows of 4. The flexor retinaculum together with the carpal bones forms the carpal tunnel. The median nerve passes through the carpal tunnel with the tendons of the flexor digitorum profundus and superficialis. The ulnar nerve enters the hand passing between the hook of the hamate bone and the pisiform bone in the Guyon canal.

The metacarpal bones articulate with the wrist at the carpometacarpal (CMC) joints. The metacarpophalangeal (MCP) joints are formed by the articulation of the metacarpal bones with the proximal phalanges (see the image below). The heads of the metacarpals form the knuckles, which are seen dorsally with the closed fist. The thumb has only 1 interphalangeal (IP) joint, while the rest of the digits have proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints.



View Image

Metacarpophalangeal joints of the digits

Each of the MCP, PIP, and DIP joints has collateral ligaments, which provide lateral stability, and a volar plate, which prevents hyperextension. The volar plate is damaged frequently in subluxation and dislocation injuries.

Blood supply: The blood supply to the hand is derived from the ulnar and radial arteries, which form the superficial and deep palmar arterial arches by anastomosis. In the absence of vascular disease, either artery alone is sufficient to perfuse the entire hand in most of the population.

Extrinsic and intrinsic muscles: The muscles of the hand are designated intrinsic or extrinsic. Extrinsic muscle bellies are in the forearm and their tendons insert into the hand, while intrinsic muscles both arise in and insert in the hand. The muscles of the hand and digits also are named according to their function as either flexors or extensors.

Forearm flexors: The forearm flexors are extrinsic muscles of the hand. These muscles arise from the medial epicondyle of the humerus and include the following:

The tendons of flexor carpi radialis (FCR), palmaris longus, and flexor carpi ulnaris (FCU) are visible in the forearm (see the image below). The palmaris longus is absent in about 14% of the population. The median nerve lies between the palmaris longus and the flexor carpi radialis (to the ulnar side of the FCR). The flexor carpi ulnaris is a good landmark to locate the ulnar nerve and artery, which lie to the radial side of the FCU.



View Image

Volar tendons at the wrist. These can be used as landmarks for injections.

Flexion of the fingers is controlled by the flexor digitorum profundus and superficialis muscles. Both of the finger flexors lie on the ulnar side of the wrist with the median and ulnar nerves and the ulnar artery. The flexor carpi ulnaris and radialis flex the wrist when acting together and cause deviation to their respective active sides when contracting separately.

Intrinsic muscles of the hand: Branches of the median and ulnar nerves innervate all the intrinsic muscles of the hand. They can be divided into 3 groups as follows: thenar (thumb), hypothenar (little finger), and lumbricals.

The thenar eminence is formed by the extensor pollicis brevis and the 3 short thenar muscles: the abductor pollicis brevis, flexor pollicis brevis, and opponens pollicis. These muscles have short tendons that insert onto the proximal phalanx of the thumb. They are innervated by the recurrent branch of the median nerve. The superficial location of this branch renders it vulnerable to seemingly trivial trauma to the thenar eminence.

Forearm extensors: Eleven muscles extend the wrist, hand, and digits (see the image below). The forearm extensors pass into the hand in 6 compartments. All forearm extensors arise from the lateral epicondyle of the humerus. They are innervated by the radial nerve.



View Image

Sagittal section of extensor compartments

Innervation: The median, ulnar, and radial nerves supply all of the sensory and motor innervation to the hand. The superficial volar and dorsal distributions of the sensory nerves are shown in the images below. The median nerve enters the hand via the carpal tunnel and often is involved in carpal tunnel syndrome. The median nerve sends motor fibers to the 3 short thenar muscles and the first and second lumbricals. The ulnar nerve sends motor fibers to the hypothenar muscles, the ulnar 2 lumbricals, the adductor pollicis, and all of the interosseous muscles. The radial nerve sends no motor branches to the intrinsic muscles of the hand.



View Image

Superficial volar sensation of the hand



View Image

Superficial dorsal sensation of the hand

Pathophysiology

The pathophysiology of soft tissue injuries of the hand is diverse. The most common mechanisms of injury are blunt trauma (eg, crush injury, contusions, abrasions), laceration, avulsion, ring avulsion, and burns. Besides skin and superficial tissues, the many muscles, ligaments, and tendons of the hand are vulnerable to injury, as are the nerves and blood vessels that supply these structures. Damage to these structures may create permanent functional and/or sensory deficits specific to the site of injury.[1, 2, 3]

Nerve injuries

Blunt, penetrating, and crush injuries to the hand result in nerve damage.[4] Nerve injury is divided into 3 types, as follows:

Dislocations

DIP: The DIP joint is stabilized not only by collateral ligaments but by adjacent flexor and extensor tendons, making dislocations of this joint uncommon. If dislocation does occur, it usually is directed dorsally and often is associated with an open wound. DIP joint dislocations are detected easily by physical examination.

PIP: The ligaments of the PIP joints are the most commonly injured in the hand. Dorsal dislocations are the most common and usually are the result of a blow to the extended digit, causing a combination of axial loading and dorsal deviation. Volar dislocations are uncommon because the joint does not resist motion in this direction. Lateral dislocation is the result of a tangential load applied to the extended digit that ruptures a collateral ligament and disrupts the volar plate. Ulnar deviation, with rupture of the radial collateral ligament, is more common than radial deviation.

MCP: Dislocation of the MCP joint is uncommon, but when it occurs deviation is usually dorsal. The common mechanism of injury is the application of a dorsally directed force that is sufficient to rupture the volar plate. Dorsal dislocations in 60-90° of hyperextension and without intervening soft tissue are simple dislocations. Complex dislocations have the volar plate entrapped between the metacarpal and the proximal phalanx. Complex dislocations are less striking in their clinical presentation but are more serious injuries.

Thumb: The IP joint of the thumb is very stable and seldom injured. Dislocations usually are dorsal and often open. The MCP joint of the thumb is one of the most frequently injured joints. Injury most commonly is caused by hyperextension force sufficient to rupture the volar plate and cause dorsal dislocation. As in MCP joints of the other digits, dorsal dislocation of the MCP joint may be a simple subluxation or complex dislocation. The complex dislocation is complicated by entrapment of the proximal phalanx.

Ligament injuries/sprains

Joints of the digits are stabilized by the combination of collateral ligaments and the volar plate. Stretching or partial tearing of the ligaments results in a sprain. The volar plate may be injured alone or in combination with the collateral ligaments. The common mechanism for an isolated volar plate injury is hyperextension during an axial load. Pain location is a good indicator of the site of injury. For example, lateral pain suggests collateral ligament injury, whereas pain on the palmar surface of the joint suggests volar plate injury. Loss of stability more commonly is associated with joint dislocation.

Sprains of the PIP and MCP joints produce pain and swelling but may lead to little or no instability. They are classified as first, second, or third degree. If the joint does not open at all but has pain with stressing of a ligament, the injury is first degree. A joint that is opened slightly in the ulnar or radial direction is defined as having a second-degree injury. This finding suggests a unilateral collateral ligament tear. A joint that is opened by at least 3-5 mm must have damage to at least 2 of the 3 structures stabilizing the joint (ie, volar plate, 2 collateral ligaments). This is referred to as a third-degree sprain or an unstable joint. Serious ligamentous injuries occur frequently and often are misdiagnosed because a mild sprain may have a similar presentation. Sequelae from missed ligamentous injuries range from chronically painful to chronically unstable or deformed joints.

Sprains of the MCP joint are rare because of the anatomy of the joint, the laxity of the collateral ligaments, and the protection afforded the joints by surrounding structures. Hyperextension of the extended digit is the most common mechanism causing sprains. Diagnosis is indicated by a stable but painful edematous joint.

The ability to hold objects between the thumb and 4 fingers is an essential function of the hand and depends upon an intact ulnar collateral ligament (UCL). Injury to the UCL is known as the gamekeeper's thumb or skier's thumb. This is because Scottish gamekeepers frequently damaged their UCLs killing game. The head of a small animal was placed between the thumb and index finger and a hyperextension/longitudinal traction force applied to the animal's cervical spinal cord by abruptly yanking the lower extremities. In a certain percentage of these procedures, the UCL of the gamekeeper was disrupted.

In modern times, skiing is the activity that most often causes UCL injury. However, a history of a missed punch, a fall onto the thumb, or the forceful removal of an object from the flexed hand also should be considered suggestive of UCL injury.

The common mechanism of injury is the forceful abduction of the thumb. Any patient with pain in the distribution of the UCL or inability to forcefully oppose the thumb has an injury of the UCL until proven otherwise.

Rupture of the radial collateral ligament of the thumb is much less common than UCL rupture. The mechanism of injury is forceful adduction of the thumb in any position.

Tendon injuries

The extensor tendons' superficial location predisposes them to injury from seemingly trivial lacerations as well as avulsions, crushes, and burns.[2, 3, 5, 6] Flexor tendon injuries can be caused by lacerations. Tendon injuries also may be sustained as the result of forced hyperextension or forced flexion of an extended digit. Injuries may include complete or partial transection, avulsion, or maceration. Whenever a tendon is damaged, particularly with an open injury, the vessels and nerves that are in close proximity may be injured.[7, 8]

Understanding that a tendon may be 70-90% lacerated and still functional is critical. Damage to these tendons may result in such findings as boutonnière deformity and mallet finger (see the images below).[9, 5]



View Image

Boutonnière deformity due to closed central tendon rupture



View Image

Boutonnière deformity



View Image

Mallet finger due to loss of central extensor tendon to the distal phalanx

Epidemiology

Mortality/Morbidity

Soft tissue injuries of the hand rarely are life threatening. However, the high incidence of disability from chronically painful or unstable joints is reflected by the fact that hand derangements account for 9% of all worker compensation claims.

The costs for treating these injuries are considerable and include not only the direct costs of repair but also the indirect costs borne by the patient, his or her family, and society. These indirect costs include, for example, time off from work and costs incurred while seeking care.[10]

History

See the list below:

Physical

See the list below:

Causes

Trauma accounts for the majority of these injuries. However, patients also present with complaints that are secondary to infection, burns, or overuse.

Imaging Studies

Plain-film radiographs of the hand or wrist should be obtained when a patient presents with a soft tissue injury suggestive of fracture or an occult foreign body. Of particular concern are lacerations from glass.

Radiography is indicated in dislocation of a DIP joint to rule out fracture.

In dislocation of an MCP joint, posterior-anterior view shows marked widening of the joint. Sesamoid bones seen inside the joint space on radiographs are diagnostic of complex MCP joint dislocation.

Ultrasonography has a growing role in locating foreign bodies and in evaluating soft tissues (see the image below). It can be used to detect ruptured tendons and ulnar collateral ligament injuries to the thumb. One can also assess the dynamic function of tendons noninvasively using ultrasonography. Ultrasound evaluation in the long axis with use of dynamic imaging allows visualization of the ulnar collateral ligament and adductor pollicis aponeurosis. Ultrasound has also been found to be accurate in diagnosing Stener lesions.[11, 12]

One prospective study found that high-resolution ultrasound (5-13 Mhz) is often superior to clinical diagnosis of many disorders, including ganglion cysts, tendinopathies, and retained foreign bodies.[13] However, it is less accurate with diagnosis of solid lesions.[13, 14]



View Image

This image shows an ultrasound of the flexor tendon of a finger with the structures labeled. It was performed using a water bath with the water as the....

MRI has been shown to be highly sensitive in detecting ruptured tendons. However, it does not have a role in emergent management of hand wounds.

Prehospital Care

Prehospital care of soft tissue hand injuries consists of application of sterile dressings and splinting, as needed.

Emergency Department Care

The prevalence and acute nature of soft tissue injuries to the hand require that the emergency physician understand the principles of evaluation and treatment.

Consultations

Orthopedic surgeon or plastic surgeon with expertise in hand injuries.[2, 1]

Complications

Complications of soft tissue hand injuries may include the following:

Prognosis

See the list below:

Patient Education

See the list below:

Author

Andrea B Lese, MD, Staff Physician, Section of Emergency Medicine, Yale-New Haven Hospital

Disclosure: Nothing to disclose.

Coauthor(s)

Kenneth R Chuang, MD, Attending Physician, Emergency Department, Long Beach Memorial Medical Center and Miller Children's Hospital

Disclosure: Nothing to disclose.

Wyatt Decker, MD, Vice President and Chief Executive Officer, Mayo Clinic Campus, Arizona

Disclosure: Nothing to disclose.

Specialty Editors

Francisco Talavera, PharmD, PhD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Eric L Legome, MD, Chief, Department of Emergency Medicine, Kings County Hospital Center; Professor Clinical, Department of Emergency Medicine, State University of New York Downstate College of Medicine

Disclosure: Nothing to disclose.

Chief Editor

Trevor John Mills, MD, MPH, Chief of Emergency Medicine, Veterans Affairs Northern California Health Care System; Professor of Emergency Medicine, Department of Emergency Medicine, University of California, Davis, School of Medicine

Disclosure: Nothing to disclose.

Additional Contributors

Dan Danzl, MD, Chair, Professor, Department of Emergency Medicine, University of Louisville Hospital

Disclosure: Nothing to disclose.

Acknowledgements

The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous author, Kahill Glenn, MD, to the development and writing of this article.

References

  1. Hegge T, Neumeister MW. Mutilated hand injuries. Clin Plast Surg. 2011 Oct. 38(4):543-50. [View Abstract]
  2. Lalonde DH, Kozin S. Tendon disorders of the hand. Plast Reconstr Surg. 2011 Jul. 128(1):1e-14e. [View Abstract]
  3. Carty MJ, Blazar PE. Complex flexor and extensor tendon injuries. Hand Clin. 2013 May. 29(2):283-93. [View Abstract]
  4. Woo A, Bakri K, Moran SL. Management of ulnar nerve injuries. J Hand Surg Am. 2015 Jan. 40 (1):173-81. [View Abstract]
  5. Drake DB, Tilt AC, Degeorge BR. Acellular Flexor Tendon Allografts: A New Horizon for Tendon Reconstruction. J Hand Surg Am. 2013 May 24. [View Abstract]
  6. Altobelli GG, Conneely S, Haufler C, Walsh M, Ruchelsman DE. Outcomes of Digital Zone IV and V and Thumb Zone TI to TIV Extensor Tendon Repairs Using a Running Interlocking Horizontal Mattress Technique. J Hand Surg Am. 2013 Jun. 38(6):1079-83. [View Abstract]
  7. Farnebo S, Chang J. Practical management of tendon disorders in the hand. Plast Reconstr Surg. 2013 Nov. 132 (5):841e-853e. [View Abstract]
  8. Scalcione LR, Pathria MN, Chung CB. The athlete's hand: ligament and tendon injury. Semin Musculoskelet Radiol. 2012 Sep. 16 (4):338-49. [View Abstract]
  9. Makhlouf VM, Deek NA. Surgical treatment of chronic mallet finger. Ann Plast Surg. 2011 Jun. 66(6):670-2. [View Abstract]
  10. Dias JJ, Garcia-Elias M. Hand injury costs. Injury. 2006 Nov. 37(11):1071-7. [View Abstract]
  11. Martinoli C, Perez MM, Bignotti B, Airaldi S, Molfetta L, Klauser A, et al. Imaging finger joint instability with ultrasound. Semin Musculoskelet Radiol. 2013 Nov. 17 (5):466-76. [View Abstract]
  12. Melville DM, Jacobson JA, Fessell DP. Ultrasound of the thumb ulnar collateral ligament: technique and pathology. AJR Am J Roentgenol. 2014 Feb. 202 (2):W168. [View Abstract]
  13. Allen GM, Drakonaki EE, Tan ML, et al. High-resolution ultrasound in the diagnosis of upper limb disorders: a tertiary referral centre experience. Ann Plast Surg. 2008 Sep. 61(3):259-64. [View Abstract]
  14. Teefey SA, Middleton WD, Patel V, et al. The accuracy of high-resolution ultrasound for evaluating focal lesions of the hand and wrist. J Hand Surg [Am]. 2004 May. 29(3):393-9. [View Abstract]
  15. Krieger Y, Bogdanov-Berezovsky A, Gurfinkel R, Silberstein E, Sagi A, Rosenberg L. Efficacy of enzymatic debridement of deeply burned hands. Burns. 2011 Nov 18. [View Abstract]
  16. Patel J, Couli R, Harris PA, et al. Hand lacerations. An audit of clinical examination. J Hand Surg [Br]. 1998 Aug. 23(4):482-4. [View Abstract]
  17. Antosia RE, Lyn L. The hand. Emergency Medicine: Concepts and Clinical Practice. 4th ed. 1998. 625-68.
  18. Chick LR, Lister GD. Emergency management of thermal, electrical, and chemical burns. Occupational Hand and Upper Extremity Injuries and Diseases. 1991.
  19. Chuinard RG, Friermood TG, Lipscomb PR. The 'suicide' wrist: epidemiologic study of the injury. Orthopaedics. 1979. 2:499-502.
  20. Cooney WP 3rd, Dobyns JH, Linscheid RL. Complications of Colles' fractures. J Bone Joint Surg Am. 1980. 62(4):613-9. [View Abstract]
  21. Cowen NJ, Loftus JM. Distraction augmentation manoplasty technique for lengthening digits of hands. Orthopedic Rev. 1978. 7:45-53.
  22. Damert HG, Altmann S, Schneider W. [The potential of high-resolution sonography in the follow-up of surgically treated flexor tendons]. Handchir Mikrochir Plast Chir. 2006 Apr. 38(2):109-12. [View Abstract]
  23. Greenspan A. Orthopedic Radiology: A Practical Approach. 1992. 2.
  24. Hergan K, Mittler C, Oser W. Pitfalls in sonography of the Gamekeeper's thumb. Eur Radiol. 1997. 7(1):65-9. [View Abstract]
  25. Idler RS, et al. The Hand: Examination and Diagnosis. American Society for Surgery of the Hand; 1990. 3.
  26. Koslowsky TC, Mader K, Gausepohl T, et al. Ultrasonographic stress test of the metacarpophalangeal joint of the thumb. Clin Orthop Relat Res. 2004 Oct. 115-9. [View Abstract]
  27. Kuschner SH, Ebramzadeh E, Johnson D, et al. Tinel's sign and Phalen's test in carpal tunnel syndrome. Orthopedics. 1992 Nov. 15(11):1297-302. [View Abstract]
  28. Lister G. Undefined. The Hand: Diagnosis and Indications. 1993. 3.
  29. Louis DS. Barton's and Smith's fractures. Hand Clin. 1988 Aug. 4(3):399-402. [View Abstract]
  30. Mehara AK, Rastogi S, Bhan S, et al. Classification and treatment of volar Barton fractures. Injury. 1993. 24(1):55-9. [View Abstract]
  31. Moore KL. Undefined. Clinically Oriented Anatomy. 1992. III:591-607.
  32. O'Brien ET. Fractures and dislocations of the wrist region. Fractures in Children. 1991. 3.
  33. Palmer AK, Werner FW. The triangular fibrocartilage complex of the wrist--anatomy and function. J Hand Surg [Am]. 1981 Mar. 6(2):153-62. [View Abstract]
  34. Salisbury RE. Soft tissue injuries of the hand. Hand Clin. 1986 Feb. 2(1):25-32. [View Abstract]
  35. Schnur DP, DeLone FX, McClellan RM, et al. Ultrasound: a powerful tool in the diagnosis of ulnar collateral ligament injuries of the thumb. Ann Plast Surg. 2002 Jul. 49(1):19-22; discussion 22-3. [View Abstract]
  36. Simon RR, Slobodkin D. Injuries to the wrist and hand. Emergency Medicine: A Comprehensive Study Guide. 1996. Vol 4: 1217-35.
  37. Skandalakis JE, Colborn GL, Skandalakis PN, et al. The carpal tunnel syndrome: Part I. Am Surg. 1992 Jan. 58(1):72-6. [View Abstract]

Metacarpophalangeal joints of the digits

Volar tendons at the wrist. These can be used as landmarks for injections.

Sagittal section of extensor compartments

Superficial volar sensation of the hand

Superficial dorsal sensation of the hand

Boutonnière deformity due to closed central tendon rupture

Boutonnière deformity

Mallet finger due to loss of central extensor tendon to the distal phalanx

This image shows an ultrasound of the flexor tendon of a finger with the structures labeled. It was performed using a water bath with the water as the conduction agent. (Image courtesy of Dr. Christopher Moore and Dr. Michael Osborne.)

Metacarpophalangeal joints of the digits

Volar tendons at the wrist. These can be used as landmarks for injections.

Sagittal section of extensor compartments

Superficial volar sensation of the hand

Superficial dorsal sensation of the hand

Boutonnière deformity due to closed central tendon rupture

Boutonnière deformity

Mallet finger due to loss of central extensor tendon to the distal phalanx

This image shows an ultrasound of the flexor tendon of a finger with the structures labeled. It was performed using a water bath with the water as the conduction agent. (Image courtesy of Dr. Christopher Moore and Dr. Michael Osborne.)