Principles of Surgery, Companion Handbook - page 44

GENERAL CONSIDERATIONS

Examination

Prior records and diagnostic images may precisely define the extent, limitations, and duration of the patient's disorder and the clinical course. The history should include information about relevant systemic disease such as diabetes, atherosclerosis, neurologic and psychiatric disorders, and other serious or chronic diseases. The examiner should use the patient's normal anatomy—the contralateral, uninvolved limb—to observe for differences in alignment, contour, and symmetry. Observing the hand and forearm at rest, in pronation and in supination, should reveal any swelling, masses, erythema, ulceration, atrophy, anhidrosis, or excoriation. The reproducibility of the patient's active participation in the examination process is important. Responses should be consistent; repeated efforts, such as in grip testing, should produce similar values.

Light palpation provides information concerning excessive or absent sweating associated with anxiety or insensibility in particular zones, nerve distributions, dermatomes, or body parts . Variations in skin contour, texture, color , temperature, capillary refill, and hair characteristics offer information regarding circulation, nerve supply, masses, and joint swelling. Abnormal, injured, and scarred soft tissues can restrain joint motion, produce skin blanching with attempted active function, or cause visible dimpling of adherent deep structures, such as injured, repaired, or adherent tendons.The nails and eponychial and paronychial tissues often mirror systemic disease as well as acute and chronic injury .

Nails have a limited range of biologic responses. Splitting and fissuring, onycholysis, and onychorrhexis may reflect loss of nail adherence to the bed matrix after trauma, aging, or malnutrition. The transverse posttraumatic nail crease that parallels the proximal nail fold and advances with growth (Beau's line) represents a single alteration of nail metabolism at the time of trauma, which is common after injury but does not include a poor prognosis . Multiple transverse grooves (Mee's lines) can occur with diseases such as Hodgkin's disease, malaria, and psoriasis and are normal in the latter part of pregnancy . Pigmented longitudinal bands may occur in melanoma, glomus tumor, and carpal tunnel syndrome. Nail bed pigmentation can be found with systemic sepsis, subungual infection, and benign and malignant tumors. Motion should be recorded with a small goniometer and strength with a dynamometer (Fig. 42-1). Simple line sketches record sites of injury, swelling, part loss, or dysfunction and can precisely record and communicate findings.

FIGURE 42-1 A and B . Common terminology used in describing hand mobility. C. The anatomy of the volar surface of the hand. (From: American Society for Surgery of the Hand: The Hand: Examination and Diagnosis, 3d ed. New York, Churchill-Livingstone, 1990, with permission.)

Imaging Studies Diagnostic imaging includes traditional roentgenography, single- and multiple-phase technetium bone scans , computed tomography (CT), and magnetic resonance imaging (MRI). Most patients should receive plain radiographs in posteroanterior, lateral, and one or both oblique projections. Radiographs provide information with relatively intermediate sensitivity, high specificity, and reasonable cost. Diagnoses can be missed if only specialized and expensive evaluations such as trispiral tomography, CT, MRI, or bone scans are used.

TRAUMA

The best care is delivered initially, when tissues are fresh and potentially can be salvaged, revascularized, and directly repaired without the burdens of secondary scar tissue after delayed healing, osteoarticular degeneration, or infection. It is in the acute situation that success is greatest in achieving a functional and aesthetically satisfactory result.

Skeletal Trauma

Carpal Bone Fractures The eight carpal bones have a large proportion of their surfaces covered with articular cartilage, and this has two clinical implications. First, the limited periosteal attachment offers a tenuous blood supply; after fracture, one of the fragments is potentially at risk for avascular necrosis. Second, most carpal fractures are intraarticular injuries. The displaced fracture often needs surgical repair to avoid secondary arthritis from joint surface incongruity. The pattern of carpal fracture or fracture dissociation may not be clearly discernible on standard posteroanterior and lateral radiographs, and oblique views, carpal tunnel projection, and other views may be necessary. If results are still equivocal , trispiral tomography or CT should demonstrate the fracture patterns and fragment positions . A technetium bone scan 72 h after trauma usually is diagnostic when the question is whether or not a scaphoid fracture is present.

Scaphoid Fracture Nearly two- thirds of all carpal fractures are of the scaphoid, occurring most often in males 15–30 years of age. Scaphoid fractures occur most commonly through the middle third of the waist or at the juncture of the middle and proximal poles. Diagnosis requires clinical and imaging information. If initial radiographs are normal but the history and physical examination suggest the possibility of scaphoid fracture, continuous immobilization in a thumb spica splint or cast is advised. Repeat radiographs in 2–3 weeks or a technetium bone scan after 72 h will make the diagnosis. Nondisplaced scaphoid fractures treated with adequate immobilization have a union rate of 90–95 percent. Displaced fractures, defined as displacement of 1.0 mm or more, are associated with avascular necrosis in one-half and nonunion in one-half of patients if not reduced and stabilized operatively.

Carpal Dislocations and Instabilities The radiocarpal and intercarpal articulations are not inherently stable on the basis of their osseous anatomy; it is the integration of osteoligamentous anatomy that secures the complex kinematics of wrist function. Most carpal dislocations are caused by an acute axial load with wrist hyperextension. The primary dislocation occurs at the midcarpal joint with dorsal displacement of the capitate. When the capitate displaces, the scaphoid must fracture or its ligaments will tear, allowing it to rotate from a horizontal position to one of vertical malalignment with the proximal pole rotating dorsally; this is called dorsal perilunate dislocation. These serious and unstable intraarticular injuries, with or without scaphoid or triquetral fracture, require careful reduction and internal fixation. The majority require open reduction. Direct trauma to the median nerve from impact, by secondary stretching resulting from dorsal displacement of the carpus, or from acute bleeding and swelling within the carpal tunnel should be identified by neurovascular examination. Carpal instabilities of all types should be treated aggressively to prevent chronic instability and dysfunction.

Metacarpal Fractures Because of their subcutaneous location and relatively rigid proximal articulations, the metacarpals represent one-third of hand and wrist fractures. Failure to reconstitute the metacarpals may lead to permanent functional deficit. Complication rates after extensive exposure for plate fixation can be high, and the risk of additional injury must be weighed against outcomes expected with conservative measures. The goal is early restoration of hand function to prevent stiffness. Whether internal or external immobilization is used is immaterial, as long as bone length and articular relationships are preserved and soft tissue management and therapy techniques can be instituted rapidly . A skin laceration caused by tooth impact often connotes an open fracture and mandates surgical treatment. Patients with human or animal bites require surgical irrigation of the fracture site or joint plus high-dose antibiotics. Rotational alignment of a metacarpal fracture is best assessed with the fingers flexed at the metacarpophalangeal joint. With an uncooperative juvenile patient or an unconscious patient, the wrist can be passively flexed and extended, with the resulting extrinsic flexor and extensor effect on digital alignment observed . Malrotation on active flexion produces a degree of visible digital overlap. Malrotation and radial-ulnar angulation interfere with hand function and should be corrected. The metacarpal neck is the most common fracture site. As with displaced and angulated fractures, the cortex on the angulated side usually is comminuted. The normal pull of the intrinsic muscles further flexes the head fragment, making it difficult to maintain reduction. The degree of angulation and the metacarpal involved determine the best treatment for the specific fracture. Because the second and third carpometacarpal joints are rigid, no more than 10–15 degrees of palmar angulation of the distal fragment is acceptable. Considerably more angulation (30–50 degrees) may be acceptable in the neck of the fourth and fifth metacarpals. Closed reduction may be achieved through the combination of direct and counterpressure applied with the finger flexed. The hand should not be immobilized in the position depicted for manipulation. Open reduction usually is not necessary, but when the fracture is unstable and residual or recurring angulation is not acceptable, internal fixation is required. Metacarpal shaft fractures should be protected when position and angulation are acceptable but reduced when they are not. Spiral and oblique fractures undergo malrotation and displacement because of the normal forces of the flexor and extensor tendons and hand intrinsics . Those which are not initially displaced or rotated must be carefully observed. Internal fixation allows more rapid soft tissue mobilization and often can be treated with percutaneous intermetacarpal pin technique, local block anesthesia, and fluoroscopic monitoring. Some of these fractures require open reduction for fixation.

Phalangeal Fractures The goal of phalangeal fracture treatment is restoration of anatomy, bone healing, and full function. Dysfunctional angulation and rotation are not acceptable. Stabilized fracture anatomy must allow rapid mobilization. Each method of fracture care has relative advantages and risks. Less invasive methods may offer less stability, but they inflict less soft tissue damage. When operation is required, the least traumatic method should be used to avoid violation of gliding structures. The patient's active participation in a rehabilitation program encompassing supervised therapy, custom splinting, and home exercises is critical for recovery of function. Proximal interphalangeal joint motion, particularly extension, can be difficult to regain if an injured, swollen finger is immobilized in flexion. Scar can tether the extensor tendons or prevent the flexors from gliding, impairing grasp and manipulation and preventing return to preinjury employment. When Kirschner wires are used, they may be buried, and they may then be retrieved in the outpatient setting under local anesthesia after 4 weeks. Sufficient fracture healing usually has occurred by then despite the delayed appearance of significant interfragmentary callus on radiographs. When Kirschner wires are left external to the skin, as in juveniles, pins must be capped and cared for meticulously. Small bone plates and screws need not be removed except to treat symptoms from the hardware.

Finger Ligament Injuries Metacarpophalangeal (MP) Joint MP joint dislocations can be managed by gentle reduction and splinting under local anesthesia. If significant residual collateral ligament instability in a particular finger is present, surgical repair is necessary. The small subgroup of irreducible fractures requires operative repair. Patients with acute collateral injuries may have a malrotated finger because of rotation about the intact ligament. Dorsal dislocations that are irreducible are characterized by dimpling of the palmar skin over a prominent metacarpal head. Interposed soft tissues can prevent joint reduction. In these patients, surgical treatment is required. Thumb MP joint injuries result from axial load and angular displacement. These injuries often occur when the patient jams the thumb into an object while falling. Disruption of the ulnar collateral ligament of the thumb is called gamekeeper's thumb, although the term was applied originally only to chronic ulnar collateral instability. Collateral laxity at the thumb MP joint is dysfunctional and painful and may lead to late arthritis. After plain radiographs fail to detect the presence of intraarticular fractures, the thumb is examined in about 30 degrees of MP flexion, gently and progressively stressing the suspect collateral ligament. Radiographs may be obtained simultaneously ; the stress radiograph is best performed by the examining physician . Treatment of incomplete collateral ligament injuries without associated instability is best done closed, with cast immobilization for approximately 4 weeks, followed by custom-splint immobilization. Soreness may persist for several months. Complete disruption of the ulnar or radial collateral ligament of the thumb MP joint should be repaired and protected by temporary pin fixation of the joint, which is most likely to give a better result and shorter period of disability than secondary reconstruction.

Proximal Interphalangeal (PIP) Joint The tightly congruent osteoarticular contours of the proximal interphalangeal joint make restoration of stable alignment of disrupted or displaced structures essential. Stiffness, rather than instability, is the outcome that must be avoided after trauma of the PIP joint. Most dorsal and lateral PIP dislocations can be treated by closed reduction and are stable. Immobilization for 10–15 days allows the patient to recover from the acute posttraumatic effects before a protected mobilization program is started with buddy tapes to an adjacent finger. Joints without an actual history of displacement, deformity, or reduction may have considerable swelling and stiffness if not mobilized early. Dislocations with fractures are more likely unstable. Postoperative immobilization that inadvertently stresses an osteoarticular fragment results in posttraumatic instability. The combination of joint surface impaction and ligament disruption has the worst prognosis. These fracture-dislocations have an outcome that is often unsatisfactory.

Palmar (Volar) PIP Dislocations In volar PIP dislocations the middle phalanx is displaced palmarward, sometimes resulting in serious instability. This PIP dislocation results from the combination of axial load and palmar vector force, most often during sports activities. Often unrecognized is that this trauma has an associated disruption of the central slip of the extensor tendon and one collateral ligament. Closed reduction and pinning or open reduction for the irreducible variant with prolonged postoperative therapy is the rule.

Distal Interphalangeal (DIP) Joint Collateral ligament injuries and dorsal or palmar dislocations may occur. Stable joints need not be pinned. In others, percutaneous fixation with maintenance of the pin fixation for 5 weeks allows the rest of the hand to be mobilized.

Fingertip Injuries Conservative treatment, such as healing by secondary intention of fingertip amputations, may result in painful scarring and deformity. However, with only a skin defect and of less than 25 percent of the pulp in adults and 50 percent of the pulp in children, conservative treatment (dressings) frequently gives the best result. There are several requirements for a satisfactory outcome after fingertip amputation: (1) Optimal functional finger length must be maintained, and additional shortening during or as a complication of treatment must be avoided. (2) The residual tip/pulp requires a resistant and resilient character like normal skin. (3) Excellent fingertip sensibility should be maintained to avoid blinding the finger. (4) Bone support for the nail is needed to minimize beaking deformity. For the thumb, every reasonable effort must be made to restore a sensate and durable pulp. Requirements for sensibility are more critical in the index and middle fingers, but they also are significant in the ulnar pulp of the small finger. Amputations can be clean and sharp, but the common injury has a component of avulsion, crush, blast, and burn, as in explosions. Explosions cause extensive trauma to surrounding skin, soft tissue, and neurovascular tissue that requires debridement and, in some cases, staging of the closure. Treatment of partial amputations, crush injuries, and partial devascularizing injuries should be directed toward preserving soft tissues. Distal phalangeal fractures, including bursting or tuft fractures, frequently are associated with crush trauma and nail bed disruption or lacerations. Nail bed injuries are not always obvious, and subungual hematoma may be the only sign of nail bed injury. Nail bed injuries should be repaired to prevent permanent nail deformity. Nail bed repairs usually are done with fine 6-0 absorbable suture. After repair, the nail that was removed is replaced beneath the cuticle to splint the bed.

Bone Shortening and Primary Closure This is performed under local or regional anesthesia and consists of debriding enough bone so that the skin can be closed with a few 5-0 sutures without tension. This method affords coverage with soft tissues of normal sensibility, and this well- padded fingertip is not painful, but the cost is some length and at least a portion of the fingernail. Inadequate bone resection produces a fingertip with unpadded bone, resulting in pain during grasping.

Composite Pulp Reattachment Reapplication of the composite of skin and pulp or skin, pulp, and bone can be done when the mass of the amputated part is very small. This choice almost always should be reserved for young children. It is best to debride any residual bone. Superficial necrosis of the reapplied part should be expected. In most situations, the reapplied tissue is a temporary biologic dressing.

Skin Grafting Grafts are a means of coverage of skin defects. The major drawbacks are sensory loss in the graft area and inadequate padding if the graft is applied directly over periosteum on prehensile surfaces. The aesthetics of the graft are affected by the donor site. The best cosmetic result for the pulp surface is achieved in all races with split-thickness or full-thickness skin graft taken from the glabrous skin at the hypothenar eminence under local anesthesia. The defect covered with a skin graft should be a skin defect, and the recipient bed must have adequate subcutaneous tissues. Skin grafts to the palm from any area other than glabrous skin is hyperpigmented. Split grafts usually are inadequate for pressure and friction surfaces. Toe-to-finger and foot -instep-to-hand-pulp skin grafting can be performed, but the short-term disadvantages are obvious as compared with full- thickness hypothenar skin as the donor.

Local Flaps Local tissue transfer from more proximally on the injured finger affords vascularized, padded, and most often sensate tissue.

Regional and Distant Flaps Cross-finger, thenar, and other heterodigital flaps have been used since the early part of the twentieth century, generally for more extensive pulp loss and otherwise uncoverable bone and tendon. These flaps have the advantage of retaining finger length but carry the risk of posttraumatic deformity or dysfunction in an adjacent donor finger. Care must be taken to avoid dysfunction from immobilization of the injured or the donor part because of nonphysiologic positioning during flap healing and before pedicle detachment. Such flaps usually are not sensate.

Replantation and Microvascular Neurosensory Flaps Microsurgical advances have made finger- and hand-part reattachment possible and have allowed reconstruction by composite neurovascular pulp tissue from toes, with or without joints and tendons. The isolated single-digit amputation in the adult usually is not suitable for replantation, especially if proximal to the PIP joint, because the functional and aesthetic recovery usually does not justify the morbidity and costs of the replantation procedure. Multiple-digit amputations, subtotal hand amputations, amputations throughout the upper limb proximal to the hand, and most pediatric amputations should be evaluated for replantation or primary composite microvascular reconstruction.

Soft Tissue Trauma

Tendon Injuries Flexor Tendons Flexor mechanism injuries in the hand and fingers usually are treated early in most patients because direct primary and delayed primary repairs offer good to excellent results even when done in the middle of the digits. Satisfactory results are reported in 75–98 percent of patients in various series. Flexor tendon repair and functional rehabilitation are a challenge. Flexor tendons are not difficult to repair, but achieving good function of repaired tendons is difficult, particularly in zones in which multiple tendons of different excursion are in juxtaposition. Tendons must glide, and simultaneously they are restrained by ligaments, such as within the digital sheath and within the carpal canal. Getting flexor tendons to glide after repair is a problem. The critical operative principle in tendon repair is to achieve near-perfect anatomic alignment of the tendon ends. There should be no gaps at the repair site, and bunching of the repair zone should be avoided to permit the repaired tendon(s) to glide within a sheath or pulley system. The zones of flexor tendons are defined by the number of tendons, restraints, and pulleys and the presence or absence of synovial membrane at that specific anatomic level. In the diagnosis of tendon disruption, the patient often presents with an open wound and loss of active motion. Observing the part at rest along with active, separate evaluation of the flexor digitorum profundus and flexor digitorum superficialis tendons makes the diagnosis. A high level of suspicion should be maintained with injuries that have loss of active flexion or extension when x-rays do not show skeletal disruption. Tendon avulsions may occur without attached bone. Closed, isolated flexor profundus avulsion is most common in the ring finger; the DIP joint will not flex, but the PIP joint does. For primary or delayed primary repair to be effective, early diagnosis is essential. Partial tendon lacerations, approximately up to two-thirds of the tendon's cross-sectional area, do not present serious risk of rupture , but the lacerated edge may catch on a nearby pulley, producing posttraumatic triggering. Lacerations involving 30–60 percent of the tendon's cross-sectional area may be treated by epitendinous suture alone. Division of 60 percent or more of cross-sectional area may be treated surgically as though division were complete.

Extensor Tendons The superficial location of the extensor tendons on the dorsum of the fingers and hand makes them vulnerable to injury, especially when the fingers are flexed. Trauma comes from lacerations, crush impacts, abrasions, and bites. Extensor tendon injuries are more common than those of flexors and often are treated casually in the emergency department. Extensor dysfunction may result in loss of active flexion from scar tethering and/or diminished active extension. The extensor system is more intricate and complex than the flexor system. The interconnections of the extrinsic digital extensor tendons from the muscles in the forearm and tendons in the hand, and the intrinsic tendons in which muscles and tendons are in the hand, are complex. The two sets of tendons collaborate to flex the MP joints and extend the IP joints. Because excursion of the extensor mechanism is limited over the finger joints, preservation of tendon length is more critical to maintain and restore tendon balance than with flexor tendon injury. The flexor tendons are thick, round, cordlike structures with spiraling fibers. The extensor tendons are thin and flat, and the longitudinal fibers of the extensors do not hold sutures well. The limited amount of soft tissues about these tendons also makes repairs prone to adherence and scarring. The extrinsic extensor tendon is the only MP joint extensor through aponeurotic sagittal fibers. Distally, the function of the intrinsic and extrinsic tendons together forms the dorsal tendon apparatus in the fingers. The direct distal continuation of the intrinsic tendon is the lateral band that continues distally to reach a position dorsal to the center of axis of PIP joint motion before crossing over the distal third of the proximal phalanx, thereby making it an extensor tendon for both IP joints. At the metaphysis of the proximal phalanx and the base of the middle phalanx, the extrinsic and intrinsic tendons converge to become conjoined extensors. The central slip inserts into the dorsal lip of the middle phalanx as its direct extensor, but the conjoined lateral bands run along the dorsal lateral edge of the PIP joint and converge distally over the middle phalanx to become the terminal tendon that inserts into the dorsal lip of the distal phalanx, functioning as this last joint's only extensor. Because of the normal dorsolateral position of the lateral bands, in certain direct injuries to the dorsum of the finger at the PIP joint the lateral bands may subluxate volarly, hyperextending the terminal joint. This is called the boutonnire deformity. When the terminal tendon insertion at the DIP joint (zone 1) is avulsed or transected, the distal joint droops, and the secondary proximal and dorsal retraction of the lateral bands produces gradual hyperextension at the PIP joint level. This deformity is known as mallet or baseball finger; it progresses to the swan-neck deformity when PIP joint hyperextension is added.

Terminal tendon injury may occur by avulsion with or without attached bone fragment and by transection from laceration or crush. Closed and open injuries usually can be treated successfully by closed means. Splints that immobilize the DIP articulation in extension (6–8 weeks) but leave the PIP joint unrestrained usually are preferred.

Zone 2 Zone 2 is the area over the middle phalanx where the lateral bands fuse to form the terminal tendon. Direct repair and terminal joint pinning for 6–8 weeks are appropriate for open cases; closed splinting for closed injuries without significant fracture is effective.

Zone 3 (Boutonnire) Zone 3 is the area over the PIP joint where the central slip and lateral bands interconnect. Injury may include avulsion of the central slip, with or without a dorsal bone fragment. The latter injuries require accurate reduction of the joint, bone, and contiguous tendon mechanism. Pinning the PIP joint in extension allows early rehabilitation of the other joints. Closed splint or percutaneous pin management may be equally effective for pure tendon injuries.

Zone 4 Most tendon injuries in zone 4 are partial, and the cut tendon ends do not retract significantly. Only direct inspection can confirm this diagnosis. If IP joint extension is normal, a partial tendon injury need not be repaired. Splinting the PIP joint for 3–4 weeks usually is adequate.

Zone 5 Lacerations and bite wounds are common at the MP joint. Bite wounds are serious contaminated injuries requiring primary surgical debridement, irrigation of the wound and joint, and aggressive intravenous antibiotics for 24–48 h. The incidence of complications is directly related to the delay in treatment. Radiographs are taken to rule out the presence of a foreign body such as a piece of tooth, an intraarticular fracture, or air in the joint, proving contamination. When caused by a bite, the wound is left open, and tendon repair is performed secondarily after healing by secondary intention. In a simple laceration, the tendon can be repaired directly. The more dorsal extrinsic extensor tendon and the sagittal band mechanism should be repaired to prevent subluxation of the extensor into the intermetacarpal valley. Primary repairs are preferable, using suture techniques described in Fig. 42-2. The wrist is immobilized in 30 degrees or less of extension, and the MP joint is splinted at 60–70 degrees or treated with a custom dynamic MP extension splint for early passive motion. The PIP and DIP joints are left free.

FIGURE 42-2 Suture techniques for the extensor tendons. Different techniques are chosen according to the size and quality of the tendon. The interrupted suture is used in zone 1, whereas core -type sutures can be used in thicker tendon tissue in zone 6.

Zone 6 Zone 6 covers the dorsum of the hand. Single or partial tendon lacerations may not produce MP extension loss because forces are transmitted through the tendinous interconnections extending from adjacent extensors, such as the juncturae tendinum. The tendons are oval in cross section and thicker here than distally. Core sutures of the type used in flexor repairs are recommended (see Fig. 42-2). The wrist should be kept in about 30 degrees of extension and the MP joints fitted with proximal phalangeal extensor cuffs with the IP joints free, allowing active flexion and passive extension.

Zone 7 Zone 7 is the proximal wrist region under the extensor retinaculum, which should be preserved or repaired. Attrition ruptures should be repaired by tendon transfer or grafting. Direct repair is almost never possible because of the wide zone of tendon trauma that occurs before breakage .

Zone 8 Multiple adjacent muscles or tendons make it difficult to identify individual tendons. The priority of repair is to restore independent wrist and thumb extension and group extension of the fingers. For repair at this level, the suture line must include fascia or the intramuscular tendinous septa to prevent pullout and failure of operation. After repair, elbow flexion and wrist extension may be needed to reduce tension at the suture line.

Nerve Injury The upper extremity is innervated by the brachial plexus and several sensory branches arising from the plexus and intercostal nerves. Classification of nerve injuries is as follows : Neurapraxia describes paralysis/dysfunction in the absence of nerve degeneration. This dysfunction is often of some duration, though recovery is always achieved in a shorter time than would be required after complete transection and nerve degeneration and regeneration. Recovery is invariably complete. Axonotmesis includes damage to the nerve fibers of a severity that causes complete nerve degeneration. The epineurium and other supporting structures of the nerve are not disrupted, so the internal architecture is relatively well preserved. Spontaneous recovery is the rule, and generally it is of very good quality because the regenerating fascicles are guided into their paths via the intact sheaths. Recovery takes longer than for neurapraxia. Neurotmesis is when all nerve structures have been divided. Laceration produces neurotmesis, but physical gaps in the nerve may occur even though the epineurial sheath appears in continuity, such as after traction or crush. At the site of damage, the nerve will be completely replaced by fibrous tissue, and there is complete loss of anatomic continuity. Recovery after nerve injury depends on successful reinnervation of sensory or motor end- organs. After denervation, muscles begin to lose their bulk; a loss of cross-sectional area without any loss in muscle fiber count begins within 1 week of denervation. Connective tissue surrounding the muscle undergoes degeneration and thickening. Interstitial fibrosis predominates over time, but passive exercises may delay or prevent this phenomenon . For function to be resumed, motor end plates must be reinnervated within 18 months of trauma. Sensory end- organs may be usefully reinnervated long after initial injury, but the quality of recovery diminishes with the passage of time. The result after repair depends on numerous factors: injury level and mechanism, associated bone and soft tissue loss, residual function, patient compliance and motivation, timing of repair, and supervised rehabilitation. Quantitative postoperative assessment of motor and sensory function should be documented. Repair should be done with microsutures with the aid of magnification to produce a spatially correct, tension-free suture line. Nerve grafts are used when direct repair after segmental loss or fibrosis would require tension at the repair site. Joint posturing into extreme flexion or extension to decrease tension at the nerve repair site should be avoided; nerve graft is substituted for such destructive splinting maneuvers. Primary or delayed primary repair should be done whenever appropriate conditions allow. The combination of group fascicular and epineurial nonreactive microsutures after identification of the internal topography should produce the best anatomic result. Repairs are protected by relaxed joint posturing for about 3 weeks, and the results of repair are maximized by beginning sensory and motor reeducation after reinnervation.

Vascular Trauma and Replantation Most upper extremity replantation surgery is based on microsurgical technique. A contaminated soft and bony tissue injury is healed by primary debridement and stabilization of open fractures, repair of extensor and flexor mechanisms, and microsurgical repair of nerves and vessels. Neither complete nor near-complete part amputation makes any patient an automatic candidate for revascularization or reattachment. Single-finger amputation in the adult, especially at a level proximal to the PIP joint, including both superficialis and profundus tendons and digital nerves, is not suitable for replantation in the vast majority of patients. Consideration should be given to replantation for thumb amputations at and proximal to the IP joint, for single-finger amputations in children, and for partial hand and more proximal wrist, forearm, or arm amputations.

Handling of Amputated Parts The amputated part should be cleansed under saline solution, wrapped in a saline-moistened gauze, and placed in a plastic bag. The plastic bag containing the part should then be placed on, not packed in, a bed of ice in a suitable container. The part should not be immersed in nonphysiologic solution such as antiseptics or alcohols. The amputated part is never put in dry ice, it is not perfused, and it should not be allowed to freeze.

Preparing the Patient The patient is stabilized, and a compression dressing is applied to the stump before transport to the replantation center. Intravenous access lines should be started and blood samples drawn while awaiting transportation. If time permits , x-rays of the stump and also of the amputated part can be obtained. Most replantation centers request that the patient be given intravenous antibiotics, an aspirin suppository (325 mg), and 25–50 mL/h intravenous supplement of low-molecular-weight dextran in dextrose, the latter for antiaggregation platelet effects.

Complications of Trauma

Compartment Syndrome/Volkmann's Contracture In acute compartment syndrome, increased fluid pressure in the tissues contained within a fascial space or subcompartment increases to a level that reduces capillary blood flow below that necessary for continued tissue viability. When untreated, continued pressure elevation produces irreversible muscle and nerve damage because of ischemia, with secondary necrosis, fibrosis, contractures, and sensibility deficits or chronic pain. Acute compartment syndrome results from an increase in the volume of fluid within a compartment or limitations on the dimensions of an anatomic compartment. Posttraumatic edema or hemorrhage, hematoma, swelling from infection, or burns increase compartment fluid, as does revascularization. Other causes include venous obstruction and transiently strenuous exercise. Constrictive dressings and casts, excessively tight surgical closure, and prolonged direct limb pressure during unconsciousness from alcohol and drugs or during extended surgical procedures add to the limited dimensions of the anatomic compartment. Acute compartment syndrome is diagnosed clinically but can be confirmed by measurement of intracompartmental tissue pressure. Clinical findings include a swollen, tense, and tender compartment with pain out of proportion to that expected from the originating injury, peripheral sensibility deficits, and finally, motor weakness or paralysis. Pain is accentuated by passive stretch of the affected muscle. Peripheral pulses usually remain intact because systolic arterial pressure usually is well in excess of the dangerously elevated intracompartmental pressure. While blood flow through the major arteries is not impeded, capillary perfusion is compromised by the elevated pressure (30–60 mmHg) within the compartment. Pressure measurement devices are confirmatory but not infallible, and in treatment decisions clinical concerns should outweigh specific pressure measurements. Threshold pressure measurements of 30 mmHg or more are consistent with compartment syndrome, and surgical decompression should be prompt. Because tissue perfusion is affected by systemic blood pressure, a lower threshold pressure for fasciotomy should be used in hypotensive patients. Treatment includes removal of all occlusive dressings, wraps, layers , and splints and splitting tight casts and cast padding down to the skin. If symptoms are not relieved rapidly, fasciotomy of the affected areas is required.

Neuromas Neuromas represent a normal physiologic response after nerve injury. All badly injured and severed nerves form neuromas, but only those neuromas which are exposed, superficial, and likely to be impacted become symptomatic. Only sensory fibers develop painful neuromas. Medical and surgical management of symptomatic neuromas may be difficult, but prevention is more important. A symptomatic neuroma is a therapeutic challenge. More than a hundred methods of surgical treatment have been described, but no method is universally successful. The symptomatic neuroma should be identified, isolated, and dissected intact. The scar bulb is kept in continuity with the nerve. The symptomatic nerve and its continuous neuroma are transposed to a deeper, more padded, and often more proximal location, beneath muscle if possible, but within bone when needed.

Reflex Sympathetic Dystrophy Reflex sympathetic dystrophy is a complex interaction of physiologic responses initiated by trauma and exacerbated by posttraumatic events. This process is staged by time and inflammatory phase with characteristic changes (Table 42-1) and by descriptive terminology (Table 42-2). The presumptive diagnosis is based on pain, which is often diffuse, burning, and hyperpathic, including allodynia (pain to light touch), hyperalgesia (painful response to nonpainful stimuli), dysesthesia (pins and needles following minor stimulus), and hyperesthesia (increased sensitivity or pain with nonpainful stimuli). Patients with reflex sympathetic dystrophy often require chronic treatments , psychological support, including counseling and medication , and an extended, intensive , and closely monitored therapy program (Table 42-3). Early recognition and treatment prevent secondary stiffness from joint and tendon adhesions.

TABLE 42-1 STAGING OF REFLEX SYMPATHETIC DYSTROPHY

TABLE 42-2 DEFINITIONS OF REFLEX SYMPATHETIC DYSTROPHY

TABLE 42-3 ORAL AND TOPICAL MEDICATIONS FOR REFLEX SYMPATHETIC DYSTROPHY

Burns

See Chap. 7.

INFECTION

Bacterial Infection

Skin infections most commonly derive from direct bacterial inoculation. Secondary spread from contiguous sites and hematogenous seeding are less likely. The most common infecting organisms are Staphylococcus and Streptococcus species; gram-negative, anaerobic, and mixed infections are seen, depending on the inoculation method, e.g., a tooth. Serious, deep infections require hospital admission and extended use of high-dose intravenous antibiotics. Wound and blood cultures are obtained before antibiotic therapy is started, and adjustments are made as indicated. Paronychial infections are common. These involve the nail and nail bed and constitute about 15 percent of hand infections. Occurrence is associated with hangnails, nail biting, finger sucking, and occupations requiring the hands to be damp frequently. Acute infection is always bacterial, creating a localized abscess, but chronic inflammation is most often yeast or fungal, requiring a different therapeutic approach. Herpetic whitlow is an infection of the soft tissues of the distal phalanx or paronychial area by the herpes simplex virus. It is characterized by intense pain and cutaneous vesicles or blisters. The vesicle fluid is clear at first but may become cloudy over a few days. It is important to distinguish this from bacterial infection. Herpetic whitlow is self-limited, generally resolving within 3–4 weeks. Felon is an expanding abscess within the finger pulp and represents up to one-quarter of hand infections. Felons also can be extremely painful, often reported as throbbing pulp pain.

Tenosynovitis Acute pyogenic digital tenosynovitis is most frequently a result of direct penetrating trauma. Kanavel's cardinal signs of tenosynovitis include (1) fusiform digital swelling, (2) semiflexed digital posture , (3) significant pain from passive extension of the finger, and (4) tenderness along the entire flexor sheath. Proper management for this closed-space tenosynovial abscess is surgical drainage and intravenous antibiotics. A high index of clinical suspicion is required for diagnosis. Aspiration of the sheath will confirm the diagnosis. In early cases, systemic antibiotics alone may be considered , but there must be profound resolution within 12–24 h; otherwise, prompt operative drainage is necessary.

Osteoarthritis and Osteomyelitis These may result from neglected soft tissue infections.

High-Pressure Injection Injuries These occur from paint and grease guns. Penetration along extended tissue planes occurs. These injuries require immediate mechanical debridement to prevent extensive loss.

Nonbacterial Infections

These include tuberculous and mycotic infections such as leprosy.

CHRONIC SYNDROMES

Tendinitis

De Quervain's Tenosynovitis Inflammation of the tendons in the first dorsal compartment and the abductor pollicis longus and extensor pollicis brevis became associated with de Quervain after his 1895 report of five cases. This tendon inflammation is one of the most common causes of pain along the radial side of the wrist and the proximal dorsoradial thumb. Injection with a steroid and local anesthetic combination is the best nonoperative treatment. As with other tendon inflammations, injection should relieve symptoms adequately and for a minimum of 4–6 months to merit repeating. When symptoms persist or recur, surgery is carried out.

Trigger Finger Chronic flexor tenosynovitis or tenovaginitis occurs most commonly in the middle and ring fingers and in the thumb and most often in postmenopausal females. The snapping phenomenon occurs as the flexor digitorum superficialis and profundus tendons or the flexor pollicis longus in the case of the thumb pulls through a tight A1 flexor pulley at the proximal edge of the sheath. There is debate as to whether tenosynovial inflammation or pulley thickening is the cause. Nonsurgical treatment should be offered except for patients with a fixed PIP joint flexion contracture that will not unlock after local anesthetic and steroid injection. Approximately 1–2 mL of steroid and local anesthetic is injected into the flexor sheath and pulley. Surgery routinely cures the problem for those unrelieved by steroid.

Neuropathies

Median Nerve The median nerve may be compressed anywhere along its course from the cervical roots to the fingertips, but the most common site is within the carpal tunnel, where it is dorsal to the transverse carpal ligament. All anatomic sites of compression must be considered and evaluated in the differential diagnosis of this increasingly common peripheral neuropathy. Carpal tunnel syndrome results from increased pressure within the rigid carpal canal, producing median nerve ischemia and physiologic dysfunction. Symptoms include paresthesias and numbness in the radial three fingers, burning digital dysesthesias, and later in the course, hand weakness or awkwardness. Focal wrist and hand pain are not a part of the syndrome, whereas nocturnal presence of symptoms is a hallmark of this diagnosis.

All treatments are designed to reduce pressure within the canal and relieve nerve. There is debate as to the cause of the increased pressure. Some have postulated tenosynovitis, whereas other studies have shown collagen, amyloid deposits, and edema as causes. Eighty percent of carpal tunnel patients are over the age of 40 years. The female -to-male ratio varies from 4:1 for idiopathic cases to as low as 1.5:1 with occupational presentation. A direct connection between carpal tunnel syndrome and forceful or repetitive use of the hands has not been demonstrated conclusively. Carpal tunnel syndrome has been associated with endocrine disorders, including diabetes, myxedema, hyperthyroidism, acromegaly, pregnancy, and the postpartum state. Chronic infections and hematologic and autoimmune disorders also are associated with carpal tunnel syndrome. Space-occupying lesions such as lipomas, bone abnormalities of the radius or carpals, posttraumatic edema, and hematomas may induce increased pressure within the canal and compromise median nerve function.The diagnosis of carpal tunnel syndrome is clinical.

Classic symptoms include paresthesias, with a predominance of nocturnal or early morning onset, burning or numbness in the median sensory distribution, and awkwardness in use of the hand. On physical examination, direct digital pressure over the median nerve at the carpal tunnel reproduces symptoms within 30 s. In Phalen's maneuver, gravity-induced wrist flexion reproduces symptoms within a minute. When direct percussion of the nerve elicits and reproduces paresthesias in the median distribution, it is a positive Tinel's sign.

Examination of motor function includes observation for thenar loss and assessing abductor muscle resistance against force. Electrophysiologic studies provide important confirmatory and differential diagnostic information. Electrophysiologic studies alone do not form the basis for this diagnosis, but surgery should not be done without electrophysiologic evaluation. Underlying peripheral neuropathies and multifocal compressions that are otherwise unsuspected may be uncovered. Electrical studies provide a baseline for later comparison if the response to surgery is disappointing. Evaluation may include studies of the median nerve as well as of a second nerve in the more symptomatic extremity. Comparison of median and ulnar or of median and radial sensory stimulation values at the wrist is useful in confirming the diagnosis. Studies are not necessarily of prognostic value for the response to surgery. Routine radiographs including the carpal tunnel view are recommended by the American Academy of Orthopaedic Surgery for evaluation and treatment of carpal tunnel syndrome. Radiographs are evaluated for carpal fractures, arthritis, Kienbck's disease, or other problems that could alter treatment. CT scans and MRI are seldom needed, but basic laboratory studies to screen for endocrine and hematologic disorders are helpful.

Predisposing medical diseases, such as thyroid dysfunction or rheumatoid arthritis, should be treated and frequently may improve or resolve the neuropathy without surgery. In pregnancy, carpal tunnel syndrome is treated by salt restriction, wrist splinting, analgesics, and occasionally, diuretics. Local injection may be needed in the third trimester. Most patients recover within about 6 months of delivery. For acute posttraumatic carpal tunnel syndrome associated with swelling or hemorrhage, loosening of constrictive bandages and moving the wrist from a position at the extreme of flexion or extension may suffice to reverse or significantly improve symptoms. Pressure studies and early surgery may be appropriate for those who do not respond. Splints and nonsteroidal antiinflammatory medications are widely used. Splints should fit comfortably and position the wrist in neutral to minimal extension. Splints are worn at night if nocturnal symptoms are a major complaint. Night splinting may be all that is required. With activity-induced symptoms, daytime splint use during provoking tasks may be needed. Oral nonsteroidal anti-inflammatory agents may be helpful, with monitoring for possible gastrointestinal and systemic side effects. Although subclinical vitamin B ₆ deficiency is a possible cause of carpal tunnel syndrome, no prospective study has demonstrated the efficacy of pyridoxine, but it is nontoxic . Local steroid injection results in improvement in 80–90 percent of patients, but there is gradual deterioration over the next 12–24 months. As with other sites, injections should not be repeated more than two or three times annually. Inadvertent injection directly into the median nerve will worsen symptoms. Surgical treatment requires complete division of the transverse carpal ligament for the entire length of the carpal tunnel under direct vision. Surgical failure is most often associated with incorrect diagnosis or incomplete ligament division. Internal neurolysis, flexor tenosynovectomy, concomitant ulnar nerve decompression in Guyon's canal, or carpal ligament reconstruction is not indicated with primary release and may be harmful . Open and endoscopic release can effectively divide the transverse carpal ligament and increase canal volume. If the patient continues to have symptoms after surgery, appropriate clinical and adjunctive diagnostic investigations should be undertaken. Incomplete ligament division or inaccurate preoperative diagnosis is the most frequent problem, but patients with hidden agendas of a nonanatomic nature may experience prolonged wound discomfort and limited recovery. In such situations, the value of preoperative electrodiagnostics becomes evident.

Ulnar Nerve Ulnar nerve compression at the elbow, the cubital tunnel syndrome, has been known for more than a century. It has been called posttraumatic ulnar neuritis and tardy ulnar nerve palsy to emphasize the traumatic causation. Distal compression in the canal of Guyon (the ulnar tunnel) at the wrist is a less common problem and more often caused by a space-occupying lesion or direct trauma. All sites of nerve compression must be considered. The differential diagnosis must include medial epicondylitis and its coexistence with ulnar nerve irritation. Some patients have the mechanical problem of a hypermobile or subluxating ulnar nerve. Ulnar traction neuritis with elbow flexion and anterior nerve subluxation reproduce radiating paresthesias in the ulnar two fingers. Patients who have actual motor weakness, and especially the subgroup with intrinsic muscle atrophy and electrophysiologic changes, have a guarded prognosis after delayed decompression. Patients presenting with medial epicondylitis should be treated for that problem, but the presence of secondary coexisting nerve irritation must be addressed. Those who do not respond to conservative measures as outlined for the carpal tunnel should be treated surgically. There is no clear advantage of one technique over the other in most patients. Ulnar tunnel decompression at the wrist must include the management of space-occupying lesions that complicate this diagnosis. Ulnar tunnel syndrome is far less frequent than compromise of the median nerve in the carpal tunnel syndrome.

ACQUIRED DYSFUNCTION

Dupuytren's Contracture

Although this disorder is associated with the nineteenth-century French surgeon Baron Guillaume Dupuytren, he was not the first to describe it. John Hunter, in 1777, and Sir Astley Cooper, in 1822, described the disease, and Cooper recommended subcutaneous fasciotomy. The pathologic proliferation is primarily of the longitudinal portion of the palmar fascia and its digital expansions palmar and dorsal to the neurovascular bundles. There is no proven relationship to trauma, occupation , handedness , or repetitive use in work or sports. Dupuytren's contracture is seen most commonly in Caucasian males of northern European descent who are in their sixth decade or older. Hand dominance and trauma are not causes; the male-to-female ratio varies from 2:1 to 10:1. Dupuytren's contracture is familial and is inherited as an autosomal dominant trait but with variable penetrance. There are significant associations with a number of diseases and conditions, the most prominent of which are diabetes and alcoholism. Human immunodeficiency virus (HIV) infection may be a risk factor. There is no effective nonsurgical treatment for Dupuytren's contracture. Operation should be reserved for those whose disease is complicated by contracture. When the patient can no longer place the hand flat on the table, the Huston tabletop test, operation is indicated. Contracture correction at the MP joint is easier than at the PIP joint. Operating on a patient with Dupuytren's contracture requires a detailed knowledge of normal hand anatomy, palmar fascial structure, and location of the pathology as it applies to the deformity, including pathologic displacement of the neurovascular bundles, which puts them at risk of injury during even the most careful of surgical release procedures. Most patients have the ulnar palm affected first and most significantly. In decreasing order, the fourth, fifth, third, second, and first rays are most frequently involved. The most effective technique is digital fasciectomy as opposed to fasciotomy. The results deteriorate with time, however; surgery does not cure the disease but treats joint deformities, contracture, and dysfunction. Fasciectomy is performed under loupe magnification and exsanguinated pneumatic tourniquet control. In addition to wound infection and skin slough, secondary swelling is a serious but uncommon complication. Prolonged pain leading to reflex sympathetic dystrophy is a difficult problem for patient, therapist, and physician. Digital nerves can be injured during operation no matter how expertly the procedure is performed, but such injury must be recognized and repaired.

Arthritis

Inflammatory Arthropathies The hand is a mirror of many inflammatory arthropathies, not just gout or rheumatoid arthritis (Table 42-4).

TABLE 42-4 INFLAMMATORY ARTHROPATHIES AFFECTING THE HANDS

Adult and Juvenile Rheumatoid Arthritis Primary consideration should be given to arthritis because of worldwide prevalence and the severe disability if untreated or, occasionally, when treated aggressively. Rheumatoid arthritis is a chronic systemic disorder of unknown cause whose major manifestation is inflammatory synovitis with secondary bone and tendon invasion and destruction. There may be late tendon dysfunction through nodularity and locking or scarring, joint subluxation, and pain. In most cases, synovitis deformities are symmetrical. Rheumatoid arthritis affects the elbows, wrists, and MP joints. Proximal IP joint involvement is less common but may be significant in a given patient. On radiographs, the hands and feet show some of the earliest signs of periarticular osteopenia, demineralization. The earliest erosions occur along the radial-palmar aspects of the metacarpal heads, at the proximal phalanges, and in the prestyloid recess of the ulna. Operative intervention is best limited to patients who, despite medical management, have persistent dysfunction because of pain, stiffness, or instability or those who have progressively worsened function and increased deformities.

Scleroderma or Systemic Sclerosis This is a generalized vasculitis affecting the skin, gastrointestinal tract , kidneys, and hands, resulting in thickened, dense, and inelastic skin and connective tissues. Pathologic joint involvement occurs in up to 80 percent of the patients. Vasculitis and secondary small joint deformity may combine to produce unstable skin, chronic ulcerations that cannot heal, and secondary infections and painful loss of use.

Noninflammatory Arthropathies Osteoarthritis Osteoarthritis is the most common upper extremity arthropathy. Although classically defined as noninflammatory, osteoarthritis is a cartilage disease with at least intermittent low to moderate levels of inflammation. Its incidence increases with age. There is a significant hereditary component, especially for women. Patients may demonstrate progressive loss of articular cartilage, seen on radiographs first as diminished joint space, with secondary subchondral sclerosis and marginal bone spurs or lipping. Joint enlargement as a result of lipping usually occurs. The prevalence of DIP joint nodularity, Heberden's nodes, is up to 10 times greater in women, especially for those with a family history. Secondary posttraumatic mechanical osteoarthritis is more common in individuals whose occupations expose them to injuries or repetitive load, motion, and impact. The inflammatory variant often affects the hands, particularly the IP joints, and can be clinically and radiographically aggressive. The IP joints (particularly the terminal IP joints of the index finger and thumb), the trapeziometacarpal, thumb basilar joint, and the pantrapezial and radioscaphoid articulations are most frequently affected. Focal small joint deformities are best treated with arthroplasty, especially in MP joints and for the less active, older patient or patients with arthrodesis at selected limited intercarpal and IP joints. For successful arthrodesis, selection of operative method is not as important as meticulous, precise technique. Stabilized continuous bone contact over the entire surface to be fused, in the presence of good bone stock with durable soft tissue coverage, produces a positive outcome. Thumb basilar arthroplasty yields functional, aesthetic results.

CONGENITAL DEFORMITIES

Failures of development, separation, and segmentation and intrauterine injury such as amniotic bands or congenital constriction ring syndrome affect mobility, facility, and self-image. Abnormalities of the shoulder and humerus, elbow, forearm, wrist, and hand produce important but different impairments, and all diminish hand facility to different degrees. Among the most common congenital afflictions in the hand are syndactyly and polydactyly. Consideration of repair should begin when the patient is 3–6 months of age.

Congenital trigger thumb may present to the primary pediatric caregiver as a snapping that may or may not be painful, but it often presents as a fixed flexion of the terminal thumb joint. Surgical release of the pulley is almost always curative.

TUMORS

Principles Localized masses are common in the hand and upper limb, but most are benign. Most have characteristics that assist in making the diagnosis. The relative rarity of malignant tumors of the musculoskeletal system distal to the elbow can lead to misdiagnosis and undermanagement. Every mass, particularly those which are atypical in appearance or location, should be diagnosed with staging and imaging procedures leading to careful incisional biopsy. Hand masses tend to present earlier, when smaller, because of their superficial location. Enlarging, symptomatic masses are evaluated with history, laboratory studies, imaging by plain films , ultrasonography, scintigraphy, CT scans, or MRI. Biopsy is the last step in diagnosis, and only very small lesions or lesions that are typical should be excised initially. Surgical staging and treatment for true malignant tumors is outlined in Table 42-5 and Table 42-6.

TABLE 42-5 SURGICAL STAGING FOR SARCOMA