AMPUTATION, FINGER

Hand and finger injuries continue to be very common problems in emergency departments (ED) around the world. In the United States, finger amputations are very common in both the work environment¹and in the home.²Finger amputations can be partial or complete. More than 90% involve the fingertip (pulp, fingernail, and/or distal phalanx) only and are treated and released in an ED.²Work-related amputations are prevalent in young males (>80%) with limited education beyond high school.¹ Most work-related amputations occur during the regular work week, while using machines such as saws, punch presses, food and beverage machines, and printing presses.^2,3 The industries where amputations are common include agriculture, forestry, fishing, manufacturing, and construction.¹ Machinery guards and shields are frequently not used by injured workers.

Most amputations, whether they occur in the home or at the workplace, are treated by amputation revision (85%) rather than replantation (15%). In Japan, replantation is attempted in 29% of cases of digit amputation. This increased rate of replantation is based on the different cultural beliefs—primarily related to Confucius teachings—and because Japanese patients with amputations are stigmatized and avoided by some people.⁴

Definitions

The amputation of a finger is the loss of any part of the index, long, ring, or little finger digits.  The lost tissue may or may not include bone.¹ The finger amputation can be partial or complete.² With a partial amputation, there may be a skin bridge still connecting the distal part of the finger to the stump. In complete amputations, there is no visible connection between the amputated part and the stump. Amputations may also be defined by the level of the transection. For example, the amputation level may be through the fingertip and fingernail, through the distal phalanx, through the distal interphalangeal (DIP) joint, through the middle phalanx, through the proximal interphalangeal (PIP) joint, or through the proximal phalanx.

Related Anatomy

Obviously, complete amputation of a finger involves all the tissues in the amputated part. Therefore, a finger amputation involves the skin, veins, extensor tendons, bone, flexor tendons, digital nerves, and digital arteries.  How these structures are managed during revision amputation and microsurgical replant are outlined in this table.

Overall Incidence

• Conn and colleagues reported that there are >30,000 non-work-related finger amputations annually in the U.S.²They also identified two high-risk groups: children aged <5 years and adults, usually male, aged >55 years.
  • Children often get a finger shut in a door, and adults are usually injured by power saws, snow blowers, and other machinery.
  • Fingers have been lost secondary to a cut, crush, bite, or burn.
  • Factors such as alcohol use, fatigue, decreased dexterity, and reflex time and medication use were cited as frequent secondary causes associated with these injuries.
• Another study⁵used 3 years of data from the National Inpatient Sample of the Healthcare Cost and Utilization Project to identify 9,407 upper extremity amputations.⁵
  • Approximately 15% of these amputations underwent replantation; the mean cost of replantation was >$40,000.
• In the U.S., amputations are very common in the workplace:
  • Amputation rates vary from 1.5 to 3.7 per 10,000 full-time workers per year.¹
  • Single finger amputations occur 81% of the time, and multiple finger amputations in 14%.¹
  • In North Carolina between 2004 and 2006, the amputation rate was 21.3 amputations per 1 million people. There was no correlation to increased numbers or immigrants.³

Related Injuries/Conditions

• The majority of upper extremity amputations are secondary to traumatic injuries; however, amputations are also performed surgically to treat severe burns, neoplasms, and uncontrollable chronic infections.
• Amputations are also the treatment-of-choice for subungual malignant melanomas.⁶
• Congenital amputations are very rare; the Centers for Disease Control and Prevention estimates 4/10,000 babies are born with upper limb reductions.⁷

Differential Diagnosis

• Traumatic amputation
• Surgical amputation for tumor or infection control
• Congenital amputation

The typical patient is a young, male worker aged 24-29 years who was working full time and injured during normal work hours. The worker will typically report he was using a press or a saw. There will likely be a history that verifies that the guards on the saw or shield on the press was not in use. The dominant hand will be slightly more likely to be the injured hand. The injured finger is likely to be the index or long finger and more often than not one finger will be amputated. If the patient is aged <5 years, the typical injury will be a crush injury of a finger caused by the finger being caught in a house or car door as it was being shut. If the patient is a homeowner, he will likely be aged >55 years. The amputation will be caused by a power tool like a table saw, skill saw, or lawnmower. Secondary factors may include: alcohol use, fatigue, decreased dexterity, decreased reflex time, and/or medication use.

• For amputations that are allowed to heal by secondary intention, the hand therapist is an excellent resource to teach the patient proper techniques for soaking the amputated stump and performing daily dressing changes.
• A hand therapist can also help patients recovering from a thumb amputation in the following ways:
  1. Instruct on how to maintain active range of motion (ROM) in the salvage joint(s)
  2. Decrease finger edema by massage and stump wrapping
  3. Minimize neuroma symptoms by desensitization techniques
  4. Teach prosthetic use and care when appropriate

• Symptomatic neuroma and diminished stump sensation²⁰
• Psychological trauma, time off from work and job change or loss¹
• Wound complications such as infections
• Bone overgrowth at stump end
• Loss of ROM in the finger remaining joints
• Contractures in the joints of the amputated finger
• Phantom limb sensation and pain
• Replant failure and need for secondary amputation revision
• Cold intolerance from the amputated stump or replanted finger
• Fingernail deformity and nail horns⁸
• Lumbrical-plus finger development and digital amputations, particularly those amputations occurring at the middle phalanx level; occurs especially in amputations of the middle finger

• Whether finger amputation should be treated with revision or replantation remains controversial.^21-23
• Finger replantation procedures achieve an average 86% survival rate of the distal part.²⁰   Guillotine amputations do better than crush type injuries.^8,23
• Active range of motion usually is greater after finger replantation.
• Finger replantation is usually associated an excellent cosmetic result; however, paresthesias and cold intolerance are present after amputation revision and after successful replantation surgery.²¹Pain can be a posttraumatic complaint in both groups.
• Amputation revision remains a straightforward procedure that is frequently done without hospitalization; rehabilitation and time lost from work is usually shorter for amputation revision surgery than for replantation.
• Despite this, lost time from work, lost jobs and placement in alternative work remain occurrences that workers often experience after a finger amputation.¹
• Pulp atrophy and nail deformity occur after replantation surgery at rates of 14% and 24%, respectively.²³Finger sensation was often acceptable even without nerve repairs.²³However, finger replantation remains a more financially costly procedure than does amputation revision, both for the healthcare system and the patient.²²

• Fingertip amputations that involved no bone or minimal bone can be managed effectively by minimal debridement and bone shortening followed by dressing change therapy. This treatment allows stump healing by secondary intention.
• Amputations to the PIP and DIP joints that are not amenable to replantation should be revised by removing the cartilage and some bone from the middle or proximal phalanx head to provide a stump that is not overly bulbous and covered without tension on the skin.
• Amputation in the long (middle) finger through the middle phalanx can be complicated by the development of a lumbrical-plus finger deformity (ie, the PIP joint extends as the patient attempts to flex the finger with the amputation).
• All revision amputations have neuromas, and all replanted fingers have either neuroma incontinuity or neuroma if the nerves were not repaired.
• Symptomatic amputation neuromas are complex problems with no simple answer.  Centro-central union of the digital nerves and the stump may decrease these annoying and troublesome symptoms.²⁴
• Patients with elective and traumatic amputations should be advised early about phantom sensations and/or phantom pain. These patients should be advised to ignore these disrupted perceptions that are caused by the damaged nerve endings sending the brain corrupted messages that are perceived as pain or the feeling that the amputated finger is still present.

New and Cited Articles

1. Boyle, D, Parker, D, Larson, C, et al. Nature, incidence, and cause of work-related amputations in Minnesota. Am J Ind Med 2000;37(5):542-50.PMID: 10723048
2. Conn, JM, Annest, JL, Ryan, GW, et al. Non-work-related finger amputations in the United States, 2001-2002. Ann Emerg Med 2005;45(6):630-5. PMID: 15940097  
3. Gavrilova, N, Harijan, A, Schiro, S, et al. Patterns of finger amputation and replantation in the setting of a rapidly growing immigrant population. Ann Plast Surg 2010;64(5):534-6. PMID: 20395810
4. Shauver, MJ, Nishizuka, T, Hirata, H, et al. Traumatic Finger Amputation Treatment Preference among Hand Surgeons in the United States and Japan. Plast Reconstr Surg 2016;137(4):1193-202. PMID: 27018674
5. Friedrich, JB, Poppler, LH, Mack, CD, et al. Epidemiology of upper extremity replantation surgery in the United States. J Hand Surg Am 2011;36(11):1835-40. PMID: 21975098
6. Martin, DE, English, JC and Goitz, RJ. Subungual malignant melanoma. J Hand Surg Am 2011;36(4):704-7. PMID: 21277700
7. Upper and lower limb reduction defects. Centers for Disease Control and Prevention2018-4-20 retrieved 2018-09-12.
8. Jebson PL, Louis DS, Bagg M. Amputations. In Wolfe SW, Hotchkiss RN, Pederson WC, Kozin SH (eds): Green’s Operative Hand Surgery 6^thEdition, Philadelphia. Elsevier Churchill Livingstone, 2010.
9. Moynihan, FJ. Long-term results of split-skin grafting in finger-tip injuries. Br Med J1961;2(5255):802-6. PMID: 13773383
10. Atasoy, E, Ioakimidis, E, Kasdan, ML, et al. Reconstruction of the amputated finger tip with a triangular volar flap. A new surgical procedure. J Bone Joint Surg Am 1970;52(5):921-6.PMID: 4920906
11. Kuyler, W. A new method for fingertip amputation. JAMA 1947;133(1):29. PMID: 20277556
12. Snow, JW. The use of a volar flap for repair of fingertip amputations: a preliminary report. Plast Reconstr Surg 1967;40(2):163-8. PMID: 5340493
13. Johnson, RK and Iverson, RE. Cross-finger pedicle flaps in the hand. J Bone Joint Surg Am 1971;53(5):913-9.PMID: 4934075
14. Smith, RJ and Albin, R. Thenar "H-flap" for fingertip injuries. J Trauma 1976;16(10):778-81. PMID: 792463
15. Foucher, G and Khouri, RK. Digital reconstruction with island flaps. Clin Plast Surg 1997;24(1):1-32. PMID: 9211025
16. Germann, G, Rudolf, KD, Levin, SL, et al. Fingertip and Thumb Tip Wounds: Changing Algorithms for Sensation, Aesthetics, and Function. J Hand Surg Am 2017;42(4):274-284.PMID: 28372640
17. Henry, M and Stutz, C. Homodigital antegrade-flow neurovascular pedicle flaps for sensate reconstruction of fingertip amputation injuries. J Hand Surg Am 2006;31(7):1220-5. PMID: 16945731
18. Carroll, RE. Transposition of the index finger to replace the middle finger. Clin Orthop1959;15:27-34. PMID: 13807969
19. Peimer, CA, Wheeler, DR, Barrett, A, et al. Hand function following single ray amputation. J Hand Surg Am 1999;24(6):1245-8. PMID: 10584948
20. Pierrie, SN, Gaston, RG and Loeffler, BJ. Current Concepts in Upper-Extremity Amputation. J Hand Surg Am 2018;43(7):657-667. PMID: 29871787
21. Hattori, Y, Doi, K, Ikeda, K, et al. A retrospective study of functional outcomes after successful replantation versus amputation closure for single fingertip amputations. J Hand Surg Am 2006;31(5):811-8. PMID: 16713848
22. Sears, ED, Shin, R, Prosser, LA, et al. Economic analysis of revision amputation and replantation treatment of finger amputation injuries. Plast Reconstr Surg 2014;133(4):827-40.PMID: 24352209
23. Sebastin, SJ and Chung, KC. A systematic review of the outcomes of replantation of distal digital amputation. Plast Reconstr Surg 2011;128(3):723-37. PMID: 21572379
24. Belcher, HJ and Pandya, AN. Centro-central union for the prevention of neuroma formation after finger amputation. J Hand Surg Br 2000;25(2):154-9. PMID: 11062573