Fingertip Injuries





CRITICAL POINTS





  • Fingertip injuries are common and account for approximately 4% of all emergency department visits.



  • Sequelae of fingertip injuries include scar contracture, cold intolerance, hypersensitivity, inadequate pulp volume, and stiffness in adjoining joints and adjacent digits with consequent long-term patient dissatisfaction or frank disability.



  • Goals of management include preservation of functional length, durable coverage, preservation of useful sensibility, prevention of symptomatic neuromas, prevention of adjacent joint contractures, short morbidity, and early return to work or recreation.



  • All fingertip injuries ultimately require referral to a hand therapy unit for optimization of outcome and minimization of long-term sequelae.



Fingertip injuries are common and account for approximately 4% of all emergency department visits. Significant costs are associated with treatment, lost work, and functional disability due to these injuries. Furthermore, long-term sequelae of scar contracture, cold intolerance, inadequate pulp volume, and stiffness in adjoining joints and adjacent digits may lead to chronic patient dissatisfaction or frank disability.


Surgical options for the treatment of fingertip injuries span the spectrum from elegant simplicity to the absolute triumph of technology over reason. Treatment decisions should ultimately be based on patient needs. These include preservation of functional length, durable coverage, preservation of useful sensibility, prevention of symptomatic neuromas, prevention of adjacent joint contractures, short morbidity, and early return to work or recreation.


Regardless of medical or surgical intervention, all fingertip injuries ultimately require referral to a hand therapy unit for optimization of outcome and minimization of long-term sequelae.




Anatomy


For simplicity we consider the fingertip as the digital unit distal to the insertion of the flexor digitorum profundus. It consists of the pulp, nail, and underlying phalanx.


The fingertip pulp is a closed space. Vertical fibrous septae anchor the pulp to the periosteum of the underlying phalanx. The pulp contains the distal arborization of cutaneous lymph vessels, as well as the terminal branches of the digital neurovascular system.


The nail unit provides support to the pulp during pincer grasp and tactile functions ( Fig. 21-1 ). It consists of keratinized squamous cells produced by the germinal matrix at the base of the nail bed. The thin epithelium of the sterile matrix provides an adherent layer for firm nail attachment. It is in turn contiguous with the underlying periosteum of the distal phalanx. The eponychium forms the dorsal roof of the base of the nail, and the paronychium is the lateral nail fold. The hyponychium is the junction of the nail bed and the fingertip skin distally.




Figure 21-1


The finger nail unit.




Surgical Considerations


Fingertip injuries are typically due to a crush or a crush–avulsion type of mechanism. They result in an injury spectrum consisting of disruption of the pulp, injury to the nail unit, and fracture of the underlying bone ( Fig. 21-2 ).




Figure 21-2


Fingertip injury in 32-year-old truck driver with loss of pulp substance, open fracture through distal phalanx, avulsion of fingernail, and laceration of nail bed following blunt injury.


Examination is best performed under loupe magnification, in a hemostatic field, and with the patient made comfortable. To this end patients are offered a regional anesthetic. It is the authors’ preference, for reasons of patient comfort, to administer wrist blockade rather than digital blockade. Multiplanar radiographs of the affected digit are then obtained. A finger cot tourniquet is applied. In the subacute setting, although the wound may initially be hemostatic, examination and debridement will shortly disrupt this. The wound is irrigated with sterile saline solution to clear blood and debris. Detailed and complete assessment is now possible. Once complete, the fingertip is dressed with nonadherent gauze, surgical sponges, and light compressive dressing. The bulky nature of this dressing generally provides adequate immobilization as well.


Fractures of the distal phalanx with fingertip injuries often involve significant comminution or bone loss. As such, operative intervention for the bony injuries alone is very uncommon.


Recall that the periosteum of the distal phalanx is contiguous with the sterile matrix, and disruption of the nail bed with tuft fractures is generally a certainty. If the overlying nail plate is not avulsed, surgical nail removal and repair of the nail bed is not performed. The overlying nail plate serves as an excellent occlusive dressing to allow for healing of the underlying matrix ( Fig. 21-3 ). If the nail plate is disrupted or avulsed, it is removed and meticulous nail bed repair is performed with fine absorbable (5-0 gut) sutures. The nail fold is then fixed, using either the native nail plate or a contoured slip of sterile foil from the surgical wrapper ( Fig. 21-4 ).




Figure 21-3


Crush injury to fingertip. A, Large subungual hematoma but without avulsion of nail from nail fold. This patient was treated with a tip protector orthosis for comfort, mobilization, and edema control. The injured nail fell off at 3 weeks, and at 9 months a new, normal-appearing nail was in its place ( B ).



Figure 21-4


A, linear laceration of the nail is approximated with fine gut sutures. B, it is commonly our practice to splint the nail folds and protect nail bed repairs with a “foil nail” made of sterile suture packaging. Note inset of the foil into the nail fold, secured proximally and distally with absorbable suture.


Linear skin lacerations may be easily repaired with fine absorbable suture. Stellate lacerations are loosely reapproximated. When the laceration involves the proximal or lateral nail folds, care must be taken to restore the anatomy without obliterating the underlying space.


The management of soft tissue loss of the fingertip with exposed bone has engendered tremendous controversy. The patient’s work demands and the desire for restoration of appearance guide the choice of treatment. Microsurgical replantation, free tissue transfer, pedicled flap coverage, soft tissue advancement, cross-finger flap coverage, thenar flap coverage, and skin grafting have been described with varying degrees of success. However, no single method is universally applicable. Indeed, no method guarantees prevention of the vexing sequelae of cold intolerance, tip sensitivity, or altered cosmesis.


Revision amputation is the most expeditious approach, but it involves shortening of the digit to the level of the head of the middle phalanx. While allowing for immediate soft tissue coverage, further shortening of an injured digit is not accepted by all patients ( Fig. 21-5 ).




Figure 21-5


Revision amputation. A, Patient with multiple digital amputations. B, Digits operatively explored, debrided, with neurectomies performed. C, Single-stage closure with local tissue.


Simple shortening of exposed bone with a rongeur at the time of initial examination followed by dressing changes allowing for healing by wound contraction and granulation allow restoration of satisfactory appearance and sensitivity. It avoids surgical intervention but generally entails a 3- to 4-week period in which meticulous wound care is required two to three times a day. Patients are instructed in dry dressing changes, secured with a lightly compressive wrap ( Fig. 21-6 ). They may incorporate full use of the injured extremity into daily hand hygiene 3 days after the injury, including gentle cleansing of the amputated tip with a mild antibacterial soap.




Figure 21-6


A, A single, dry gauze is placed to cover the fingertip without excessive bulk. B, This is overwrapped with a light compressive dressing. This may easily be changed daily by the patient.


More recently, the application of topical growth factors with dressing changes has been shown to yield results superior to and less costly than surgical soft tissue reconstruction. It is unclear whether these offer any advantage to less technologically sophisticated wound care.


We have enjoyed great success with this method, but concerns over bone dessication and osteomyelitis lead some to abandon this method except in the smallest of injuries.


Full-thickness skin grafting of pulp and tip defects enjoys limited benefit over simple healing by secondary intention. Although donor site morbidity is minimal, the fingers are immobilized for 7 to 10 days to allow for graft incorporation. A mature graft is relatively anesthetic, and graft contracture may lead to poor cosmesis.


Full-thickness pulp defects, with exposed bone or tendon, are typically not amenable to healing by secondary intention. These injuries have more recently been treated by us through a staged procedure involving the application of an acellular dermal matrix followed by full-thickness skin grafting at an interval of 3 weeks ( Fig. 21-7 ). This technique allows for preservation of length and contour, but carries with it the costs of two procedures and a heavy expense for the acellular matrix template.




Figure 21-7


Staged reconstruction of full-thickness pulp defect ( A ) with application of acellular dermal matrix ( B ). At 3 weeks the matrix is ingrown and provides a suitable bed for skin grafting ( C ).


Homodigital flaps, such as the V – Y advancement flaps have been in use for decades with little modification of the original technique described independently by Attasoy and Kutler ( Fig. 21-8 ). Tissue is advanced based on deep septal perforating vessels. There is no need for prolonged immobilization, and no donor site morbidity results. Clinically, however, the extent that tissue may be advanced distally is limited. Although advancement up to 10 mm is possible, considerable dissection is involved and possibly devitalization of septal perferators.


Figure 21-8





A, Artist’s rendering of V – Y advancement flap for fingertip coverage

(Reprinted with permission from Green D, Hotchkiss R, Pederson W, eds. Green’s Operative Hand Surgery , 4th ed. Philadelphia: Churchill Livingstone, 1999, p. 1804.)


The adipofascial “turnover” flap is a reasonable option for coverage of large full-thickness defects to the dorsum of the fingers. This flap is based on constant dorsal cutaneous perforating vessels arising from the proper digital arteries at the level of the proximal interphalangeal joint. The flap may be extended to offer durable coverage to the entirety of the digit from the proximal interphalangeal (PIP) joint to the fingertip dorsally. A full-thickness skin graft is applied over the flap while the donor site may be closed primarily ( Fig. 21-9 ).




Figure 21-9


Adipofascial turnover flap. A, Left hand of a 52-year-old craftsman following auger injury. B, Adipofascial flap harvested from proximal finger and rotated distally based on perforating vessels at level of proximal interphalangeal joint. Coverage is obtained to the level of the fingertip. C, Full-thickness skin graft applied. D, Three months after surgery. Patient was self- employed and returned to work 10 days after surgery following removal of operative dressings. He continued with Coban wrap while at work.


Heterodigital flaps such as thenar flaps and cross-finger flaps further expand the surgical armamentarium for fingertip reconstruction. These are random flaps raised either at the base of the thumb or off the doral aspect of an adjoining digit. The injured digit is secured to this flap and sectioned 14 to 21 days later at a second surgery. The donor site is typically covered with a skin graft ( Fig. 21-10 ). This iatrogenic syndactylization of two digits, often with the PIP joint in midflexion, has an inherent propensity to lead to permanent flexion contracture. Although we have found these complications to be common, several authors assure us that this sequela is rare.


Apr 21, 2019 | Posted by in PHYSICAL MEDICINE & REHABILITATION | Comments Off on Fingertip Injuries
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