Introduction
Anatomy
Assessment of the Hand
Treatment
Specific Treatments
Nail Bed Injuries
Fingertip Injuries
Mallet Finger
Bites: Human, Animal
Injection Injuries

Burns

Extensor Tendons

Flexor Tendons

Splinting and Rehabilitation

Conclusion

References

Questions

Clinical Pictures

Introduction
This article will review the general principles which should be kept in mind while providing emergency care of the hand, including assessment and follow-up care. I will then review some of the common problems that present to the surgeon on an emergency basis.
In the western world there is increasing specialization, and as a result hand problems are often treated by subspecialists. In the developing world, the general surgeon will often be the only source of care, so it is important to know how to manage many different hand problems. Maurice King in Primary Surgery provides very practical suggestions for the inexperienced surgeon. (1;2) In a study of open fractures, hands were only 1% of the cases (3) while another study suggested that hand injuries made up 14% of unintentional trauma costs.(4) While a hand injury is rarely a cause of death, it can be a source of long-term disability in patients. The best hope for a good outcome lies in providing the best possible care with the initial treatment. Salvage treatment at a later date is both difficult and less likely to have a good functional outcome.

Anatomy
Anatomy is key in the management of hand injuries, as we are often trying to restore normal anatomy after trauma (5). The placement of incisions is also based on avoiding injuries to underlying structures as well as preventing long-term disability from a poorly placed incision. If you are uncertain of the anatomy prior to an operation, take the time to review it. In brief, the hand has both flexor and extensor surfaces, and these will need very different approaches when injured.

	The extensor surface is thinner; therefore there is less protection for the underlying structures. The spaces do not tend to limit the spread of swelling or infection.

Figures from Current Diagnosis and Treatment in Orthopedics. 3rd edition published by Lange

On the flexor surface of the hand the thicker skin will provide some increased protection of the underlying structures. The bursas are well developed and tend to limit or direct the spread of infection. This may also minimize the signs of infection and restrict the appearance of fluctuation even with an underlying abscess.
Figure from Emergency Medicine: A Comprehensive Study Guide 6th edition (2004)

Assessment of the Hand
As with any patient you must first take a history, and look for any other injuries that may take precedence in treatment. If then appropriate, focus on the hand exam.(6) What was the mechanism of injury? Was there a fall, mechanical trauma, history of a fight or animal bite? Look at the hand. Is there active bleeding of gross disruption of tissue? At rest the normal hand has a cascade of finger flexion from index to the small finger. If a finger is out of sequence there may be a tendon injury (less flexed suggests flexor injury, more flexed an extensor injury). Is there a deformity suggestive of fracture or dislocation? Are there swelling, heat and redness suggestive of infection? Is there evidence of vascular injury with cool, pale fingers, poor capillary refill of the nail bed or arterial bleeding?
Next do a brief physical exam, taking into consideration any obvious injuries. Flexors are tested with all the fingers in extension, testing both sublimus and profundus. If active flexion seems intact, try gentle resistance as flexion may be present with near complete tendon lacerations. The presence of pain with resisted flexion suggests a tendon injury. When testing for extensor function, remember to place the MP joints in extension as the intrinsics can provide extension with the MPs flexed. Sensation is easily tested using 2 point discrimination with a paper clip tip bent 5mm apart. Look at the site and mechanism of injury for probable sensory loss.
It is important to test and document all deficits at the initial exam. This will help direct your operative treatment, and even if you will be unable to repair an injury, you can let the patient know what to expect in the future.
If X-rays are available, they may show not only fractures or dislocations, but foreign bodies, swelling or evidence of osteomyelitis.

Treatment
Once the patient has been assessed, the initial treatment can begin. Where possible this should include assessment of tetanus status and updating immunizations as required. Significant bleeding can be controlled with direct pressure. Rarely is tourniquet or blind clamping of vessels required. The wounds should be cleansed with saline and perhaps an antiseptic, or if that is not available just soap and water. If there is an open wound, cover with a clean moist gauze and splint as needed to prevent further injury.
The use of prophylactic antibiotics is controversial. For clean, sharp wounds treated promptly they are probably unnecessary. For crush injuries or those involving bone they are likely of use. A first generation cephalosporin or penicillin with staph coverage is often used, but this will be altered by specific injuries. (7) You must now decide on specific treatment. If an operation is necessary, do you have the skills and facilities to fully correct the problem? If you do not, what are the options for referral? If referral is not available, what can you do to best achieve healing with maximum function?
With open wounds, even if referral is available, the wounds should be cleaned. Unlike the aggressive debridement used following trauma in other areas, we must be a little cautious in the hand. While obviously dead or necrotic tissue must be removed, try to preserve nerves, tendons and vessel wherever possible. Excision of skin should be limited to what is absolutely necessary since overly aggressive debridement may create difficulty with wound closure later. Avoid bone shortening on the thumb if at all possible to maximize function. In badly mangled digits, primary amputation may be the best course if you think long-term function will be poor. This is especially true for border digits (index and small) where patients will tend to exclude the non-functional digit. If you will be referring the patient immediately, you may loosely close the wound if possible without excess tension, place in a splint and elevate the limb.
Tourniquet use is essential in all hand surgery to provide a bloodless field. This allows the identification and protection of all structures and will make the surgery both easier and safer. For operations distal to the proximal phalanx a digital tourniquet works well. I normally use a ¼ inch penrose drain, but a finger cut from a sterile glove also works well. Simply cut off the tip of the glove finger and roll it onto the finger. For more proximal injury it will be necessary to use an arm tourniquet. If you do not have one, a blood pressure cuff can be used. The upper arm should be padded with 2 layers of cast padding before applying the tourniquet. Once the arm has been prepped and draped, and you are ready to start the surgery, the tourniquet can be inflated. For upper limbs this should be set at 50-100mm above the patient’s systolic pressure. Under local anesthetic most patients will tolerate 20 minutes of ischemia, under general anesthetic it can be left up for 2 hours. If more time is needed, it should be released for 20 minutes before re-inflating. If available, use a sterile Esmarch to exsanguinate the arm first, or simply hold the arm up for 30sec with the radial and ulnar arteries compressed before inflating the tourniquet. Exsanguination should not be used with infection, tumour or injection injuries due to a risk of contamination.
Some form of hand table is also desirable for surgery, at a level that allows the surgeon to sit. Two arm boards set up next to each other will work well, and the patient should be positioned so that the injured area is comfortably on the operative surface.

Specific Treatments
Nail Bed Injuries
Standard thinking has been that with an intact nail and a subungual hematoma of greater than 50% of the nail bed it is best to remove the nail and do a direct repair. However a study comparing two methods found equally good results with the use of trephination to decompress the nail bed. (8). This is readily done using the heated tip of a paper clip. In the West where concern for appearance may be more intense, one group has shown that initial split thickness nail bed grafting from a great toe donor site gives good cosmetic results in patients where the nail bed tissue has been avulsed. (9)

Finger tip Injuries
Crush injuries and amputations of the fingertips are very common injuries with a range on treatment options. The goal is to provide a padded, sensate tip with minimal pain in a reasonable healing time. There is general agreement that wounds of 1cm or less can be left to close be secondary intention, but some authors prefer this method for wounds up to 1.5-2 cm. (10) The use of topical growth factors are also being explored as a way of speeding healing. (11). The use of composite grafts has generally fallen out of favor due to high failure rates, but one author had up to 70% success rate. This seemed most suitable in clean cuts or avulsions that involved a small portion of distal phalanx, and he advocated minimal debridement of the graft. Success was decreased greatly with smokers. (12). Other methods of closure include split thickness graft (STG), full thickness graft from the hypothenar area (13) and many local flaps.(14;15). Most authors would agree that you should use simpler methods if you are unfamiliar with the more complex methods. Changing dressings every 2-5 days, topical antibiotics and a non-adherent dressing are part of the protocol in most treatments.

Mallet Fingers
These injuries can be open or closed, and may involve a portion of bone avulsed at the insertion of the extensor tendon at the distal phalanx. Although a seemingly minor injury, this can lead to a swan neck deformity long-term if not treated, and so it should not be ignored. Judging by the number of articles written of this subject, almost everyone has an opinion on the best treatment. If the wound is open, most would treat with direct suture of the tendon, and K-wire fixation of the DIP joint in extension for 6 weeks. It is the management of the closed injury that is more controversial. Splinting of the DIP joint in slight hyperextension for 6-8 weeks shows good results, even if treatment has been delayed. Care must be taken in protecting the dorsal skin, and preventing any droop of the DIP when the splint is being changed. (16-18) When the fragment of avulsed bone is greater that 1/3 of the articulate surface, many but not all authors would suggest K-wire fixation, and several methods have been suggested.(19;20) In reviewing these articles I was impressed with the good functional results and patient satisfaction from simple splinting, and this is what I plan to do.

Bites
Human
These usually result from a fight where the clenched fist meets to tooth of the opponent. These are a notorious cause of infection both due to the mechanism of injury, and the delayed presentation of the injury and often unreliable patient.
With the clenched fist, the tooth will often not only break the skin, but also penetrate to tendon and joint capsule. When the finger straightens, the tendon and joint injuries become hidden, and bacteria become deep seated within the hand. If these patients present early, the wound should be explored and irrigated, the hand splinted and oral antibiotics started. If they present late, they will need to be explored in the operating room for a wider debridement and admitted for IV antibiotics. Recommended antibiotics are amoxicillin/clavulonic acid or a 1st generation cephalosporin.(21-23)

Figure from Current Diagnosis and Treatment in Orthopedics 3rd edition (2003)

Animal
In the West the majority of animal bites involve either cats or dogs, but in the developing world other animals or wildlife may play a role. Cat bites tend to be puncture wounds with a high risk of infection. Unless very superficial the risk is great enough to justify the use of prophylactic antibiotics. (24) Dog bites tend to be more destructive with greater tissue damage (25). The need for antibiotics must be individualized, and antibiotics are never a substitute for thorough wound cleansing. More exotic injuries such as snakebite can occur in the developing world, but in this the focus is more on the management of any venom inoculation rather than the wound per se.

Injection Injury
This form of injury bears special mention because the initial injury is often deceptively innocuous, and therefore under treated. When first seen there may be only a pinprick or abrasion visible. X-rays will sometimes show the extent of spread of contamination. The most common finger injured is the non-dominant L index, and history is the key to diagnosis. The seriousness of the injury varies with injection pressure, agent injected and volume injected. Injection with gas is the only case that can be treated non-operatively with antibiotics and splinting. All other agents will involve a surgical approach. This is aimed at decreasing the load of foreign material, and decompressing the finger or hand. Amputation rates of 50% can occur with some agents and long-term stiffness is common. Grease, paint and hydraulic oil are the most common agents to be injected. It is important the patient understand the seriousness of the injury when they are first seen.(26-28)

Burns
The hand and upper limb is frequently the site of a burn, up to 89% of all burns in one study. (29) In the developing world it is frequently children who are involved, by falling into a fire, or pulling down a scalding liquid. (30) I will not get into the general treatment of burns, but want to emphasize the role of early mobilization and proper splinting to prevent or minimize long-term contractures. Splinting will generally hold the wrist in 30 degrees of dorsiflexion, the MPs in 70 degrees or more of flexion and the IP joints in full extension. If the hand is burned, the fingers should be dressed separately to maintain the web space and avoid syndactyly from forming. When possible early excision of the burn and sheet rather than meshed STG will give a better cosmetic and functional result.(31;32) (33) Splinting may be required at night for some time after the burns have healed to prevent contracture, as well as physio to mobilize the hand. When physiotherapists are not available it is important the surgeon explain to the patient and family the importance of physio and splinting and supervise the treatment. If contractures occur there are several operations that have been suggested, from skin grafting to some form of flap (34;35) In the growing child the need for this may occur some years after the initial burn. One study reported an impressive improvement in function with grafting a contracture 20 years after the original burn.(36)
Chemical burns are a special subset of burns, and may occur when workers are not aware of the importance of safety measures, or they are not available. (37) The emphasis is on removing the agent by dilution with large volumes of tepid water, including removal of any clothing which may be contaminated. Chemical burns may continue to evolve after presentation if the agent is within the tissue. Calcium gluconate is used as a specific antidote for burns with hydrofluoric acid.(38)

Infections
Infections at any site are a common problem in the developing world, and the hand is no exception. These may occur after an injury, especially any form of puncture wound (39) The history may suggest a foreign body which can be looked for on X-ray. History may also suggest unusual organisms, for example mycobacterium marinum in those working with water (40), or other unusual infections seen with fishing injuries.(41)
The surgeon is often involved when there is a suspected abscess, and the question of need for drainage is raised. The hand, especially on the volar surface has many compartments which can act as areas of containment for the infection, and fluctuation can be a late sign. The cardinal signs of infection are pain, often of a throbbing nature, redness, heat and swelling. Fever may also occur, and there will be some loss of function in the hand. On the dorsum of the hand the tissue planes are flimsier, so swelling will show readily. On the volar surface the compartments tend to hold any pus under pressure and therefore cause more severe pain. In the nail bed this is known as a paronychia; in the pulp space, a felon. If contained within the tendon sheath it is a tenosynovitis, described by Kanavel in 1912 with 4 cardinal signs: finger held in slight flexion, uniform swelling and redness of the finger, severe pain on passive extension of the DIP and tenderness along the flexor tendon sheath. In web space infections there is marked edema, and the adjacent fingers are held apart by the pressure of pus in the web space.
What all these infections have in common is the need for immediate drainage. Delaying until the next day will only allow progression of the infection and more destruction within the hand. Starting IV antibiotics while pus is still under pressure in the hand will do very little to improve things, so do not delay drainage. If the OR will not be available in a timely fashion, a small incision to drain the pus will buy time. On the volar surface of the hand fluctuance is a late sign. If no fluctuance or draining pus is present, base your incision of the point of maximal tenderness. It is important that all pus be drained and the wound be left open. For tendon sheath infections, the use of an irrigation catheter in the tendon sheath is sometimes suggested.
Since the hand contains many vital structures near the surface, placement of the incisions to avoid undue disability is important. Use a tourniquet, but do not exsanguinate the arm in the presence of infection (also applies to injection injury) to avoid any spread of infection. Be aware of the underlying structures, especially nerves and vessels which can be readily cut with aggressive scalpel or scissor use.

 

Figures from Campbell’s Operative Orthopedics 10th edition, published by Mosby
The above diagram illustrates some safe sites for incision. Note that on the flexor surface an incision must not cross a flexion crease at 90 degrees as this will lead to a contracture as the scar shortens. Following the initial drainage, it may be necessary to return to the OR for further debridement or dressing changes. The hand should be splinted and elevated to promote healing, and active motion encouraged several times a day as soon as possible.

Extensor Tendons
In general extensor tendons are readily repaired, and are a good place to start if you are learning tendon repairs. With the exception of the extensor pollicis longus, these tendons do not usually retract far when cut, so the ends are easier to retrieve than with flexors. Suture material has usually been non-absorbable, and I have found that a 4-0 braided suture works well. The monofilament sutures have the disadvantage that the stiff cut ends will often poke through the thin dorsal skin at some point and occasionally need to be removed. Length of splinting after repair is usually between 6-8 weeks depending on the level of the repair. It is worth reviewing this in an ortho or plastics text if you will be doing repair.
Central slip injury deserves special mention. This can occur after a laceration or blunt injury to the dorsum of the PIP (42;43). It may be missed initially as the lateral bands will initially continue to extend the PIP. If recognized, a period of 6-12 weeks of extension splinting can prevent the problem. If not picked up, a boutonniere is a challenging problem to fix late.

Flexor Tendons
If you will be repairing flexor tendons, you will need to review a text on the subject. I will discuss only a few principles and pitfalls. The trend has been to perform primary repair of all divided flexor tendons at all levels, and in experienced hands this will produce good results. With less experienced hands, it is possible to make things much worse by attempting repair and the surgeon must decide what will work best in his(or her) hands. In tendon lacerations of less than 50%, it has been shown that repair is not necessary to maintain strength. There have been reports of triggering occurring in partial lacerations, but this is uncommon.(44)

Figures from Current Diagnosis and Treatment in Orthopedics 3rd edition(2003)
The flexor surface is sometimes thought of in 5 zones for repair. In zone I injuries the profundus is divided, with an intact sublimus. If the injury occurred with a flexed hand, the proximal end may be retracted and difficult to retrieve. Unless both ends are lying in the wound, this repair is left for more experienced surgeons. Zone II is the classic “no man’s land” through the pulley system. If a repair is done, at least the A2 and A4 pulleys must be maintained to prevent bowstringing. Best referred if you are not experienced. Zone III is an easier site for repair, but be alert for the nerves and vessels in this region. They may need repair and must be protected if not injured. In Zone IV and V primary repair should be possible by most general surgeons. All operations should be done under tourniquet control, and the post-op care will be as important as the operation to achieve excellent results. The review article by Strickland (45) outlines the current thoughts on treatment. The role of the hand therapist is emphasized in the literature (46;47), but in the developing world that role must often be filled by the surgeon and the patient. This makes it even more important that the surgeon explain to the patient what is expected, and continue supervision until recovery is complete. The concept is to allow as much movement as possible while preventing disruption of the repair. The repair tends to be weakest at 2-3 weeks, with maximum strength at 12 weeks. Various forms of protected motion have been suggested, and you must decide what you can do in your facility. Dynamic splints can be made using plaster, rubber bands and safety pins, so they need not be expensive.(48;49)

Splinting and Rehabilitation
After a hand problem has been treated, some form of splinting will often form an important part of the recovery. With infections, splinting will rest the hand to allow a faster recovery, as well as minimize the risk of contractures. With tendon or ligamentous injuries, splinting will help in tissue healing. A position of 30 wrist dorsiflexion, 90 degrees of MP flexion, and all IP joints in full extension is one that will prevent shortening of collateral ligaments at the joints and thus minimize the risk of contracture. This may be modified after flexor tendon repair in which the wrist is placed in 50 or 60 degrees of volar flexion to take the tension off the repair. With an extensor repair the MPs may be placed in only 10-15 degrees of flexion to take tension off the repair. If a burn is on the dorsum of the hand and wrist, it may be necessary to place the wrist in volar flexion so that the splint is opposing the forces of scar contracture. Always think about what you are trying to achieve and protect as you design your splint.
As important as splinting is, movement is our ultimate goal. Therefore once structures are stable the splint can be removed to allow controlled exercises. Initially this may involve removing the splint 3 or 4 times a day for exercises, or using it only at night. In burns splinting may be needed for a longer period for scars crossing joints.

Conclusions
Hand injuries are a common problem which can involve complex surgical decisions. Try to treat patients in a timely fashion to decrease morbidity, and pick up the problems which have simple solutions early on, but disastrous consequences if missed. If you have little experience in hand surgery, tackle the smaller repairs first to build up your skills for the more complex surgeries.

Barbara LeBlanc
General Surgeon
Guelph, Canada

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