Добавил:
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
Скачиваний:
38
Добавлен:
20.06.2014
Размер:
561.93 Кб
Скачать

10

The Hand

MUSTAFA A. HAQUE

The human hand is one of the most important interfaces of a person’s body with the outside world. It allows us to touch, feel, manipulate, and modify our environment. Its cortical representation in the brain is nearly as large as the rest of the musculoskeletal system combined. Loss of hand function can have devastating effects on a person’s ability to work or perform activities of daily living. Unfortunately, because of its constant use and its position at the forefront of human activity, it is frequently affected by trauma and other disease processes. Nearly all physicians will see patients with hand problems, so some familiarity with these processes and basic hand evaluation is very important.

History

As in all fields of medicine, the history begins by carefully determining the patient’s chief complaint, followed by a detailed history of the present illness. It is also very important to obtain supplemental information important to hand function, such as hand dominance and the patient’s specific use patterns for his or her hands such as occupation, sports involvement, and hobbies.

The history of present illness is tailored to the patient’s chief complaint and does require some background understanding of various pathologic processes in the hand and upper extremity. In patients with congenital hand differences or birth-related injuries, one must obtain a careful understanding of the gestational and birth history. One must inquire about gestational diabetes, preeclampsia, and other maternal and fetal health problems, including exposure to teratogens. The presence of consanguinity or a family history of similar anomalies should also be determined. The physician should also see if improvement in the condition has occurred and determine some of the parental goals and expectations of outcome.

In nontraumatic situations, it is important to have the patient focus as closely as possible on the exact site of the problem and to try to analyze

387

388 M.A. Haque

the history of onset, the progression, and interventions. An understanding of what helps relieve symptoms and what aggravates them can be very important in determining treatment. In patients who attribute their problems to repetitive activities, it is further important to understand the length of time it takes before symptoms begin, how long the patient had been doing this activity before this problem developed, and whether symptoms are now present when the patient is not involved in these activities.

When a traumatic injury is present, the exact nature of the injury and the surrounding circumstances under which it occurred should be carefully noted and documented; this includes such information as the environment in which this occurred, whether it was clean or dirty, and whether the patient perceives that the injury was caused by another person’s fault, their own error, or an unavoidable circumstance. Many of these patients later become involved in worker’s compensation or other medicolegal litigation. By carefully determining and recording the events that occurred, the treating physician can give the most accurate representation of the injury and avoid later difficulties in trying to reconstruct events from memory.

Many times these patients present late after having been treated elsewhere or having avoided treatment altogether. In these stages, it is very important to note the evolution of the patient’s problems, what treatments have occurred, and what are the current functional losses.

The remainder of the patient’s medical history is also quite important. A good understanding of the patient’s diseases including the presence of diabetes, hypothyroidism, heart disease, or other problems can help determine factors contributing to a hand problem. Previous surgical history, including complications of anesthetics, is also very important in the treatment process. Medications and allergies have obvious implications in the treatment. Social history should include the patient’s occupation and hobbies as well as tobacco, alcohol, and illicit drug use. Family history and review of systems that include questions about the patient’s psychiatric history help complete a thorough evaluation of the patient’s history.

Physical Examination

In the physical examination of the hand and upper extremity, one must often start proximally at the neck or shoulder, especially for nerve and tendon problems. One begins the evaluation with observation of the upper extremity, looking for atrophy, deformity, or any other lesions with comparison to the opposite side. Palpation of the area of the chief complaint should be performed next. In this section, one should make every effort to localize the patient’s pain or other complaints as anatomically as possible to help define the diagnosis. An understanding of the surface anatomy is critical. For example, one must know that the scaphoid waist underlies

10. The Hand

389

the anatomic snuff box and that the A-1 pulley of the flexor tendon sheath is at the level of the metacarpophalangeal joint. Next, one should determine both the active and passive range of motion of the elbow, wrist, and hand. This information should be recorded carefully for later comparison testing.

Injuries that involve open wounds of the hand and upper extremity should rarely, if ever, be probed or explored on the initial evaluation. Examination of the distal hand function can usually determine what structures are injured. Vascular function can be determined by evaluating capillary refill or performing a Doppler ultrasound evaluation of pulses distal to the laceration. Flexor and extensor tendon function can almost always be determined by evaluation of active range of motion. Nerve function can be assessed by performing motor and sensory examination as well. In evaluating the sensory function, it is often helpful to obtain some quantifiably measured data such as two-point discrimination or Semmes– Weinstein monofilament threshold testing. For young children, assessment of wrinkling after immersion under water or the presence or absence of sweating can be helpful, as they are functions of the autonomic nervous system and cease as soon as a peripheral nerve is cut.

Specialized testing for specific injuries or problems can help confirm a diagnosis, and these tests are addressed under the sections describing those specific disease processes.

Imaging

Imaging of the hand and upper extremity typically starts with plain radiographic evaluation. The standard views used in the hand and wrist include anteroposterior (AP), lateral, and oblique views, and all physicians who will ever evaluate the hand should have some familiarity with the basic radiographic anatomy of the carpal, metacarpal, and phalangeal bones in these views. In particular, one should be recognize the overall alignment and arcs that are present to avoid missing a dislocation in an emergency room setting. There are many additional special views, such as a carpal tunnel, a Brewerton, and scaphoid views, that help profile specific injury patterns.

Advanced imaging modalities are used for disease or injury processes that are more difficult to define. Bone scans can be very useful for helping define infection, reflex sympathetic dystrophy, and occult fractures. Computed tomography (CT) scans are helpful for better understanding bony lesions and defining tumors. Magnetic resonance imaging (MRI) is typically the imaging modality of choice for soft tissue lesions, and it is also becoming more frequently used for occult fractures. When accompanied by an arthrogram, it can be very helpful in diagnosing ligamentous injuries of the wrist. Ultrasound is rapidly becoming a very useful imaging tech-

390 M.A. Haque

nique as well, especially to define soft tissue lesions, bony abnormalities, and ligamentous injuries. It can be particularly helpful in differentiating between rupture or scarring of a tendon repair and for visualizing foreign bodies that are not radiopaque. Ultrasound allows for a dynamic study in which tendons or other soft tissue structures can be evaluated while they are moving. It is an extremely cost-effective imaging modality, but, unfortunately, at this time it is still very operator dependent.

Arthroscopy

Arthroscopy has become an important treatment modality for the wrist in particular. In some situations, such as chondral injuries, some ligament tears, and capsular tears, it is the best way to make a diagnosis as well. As the technology and experience level increases in these techniques, arthroscopy may become an important diagnostic and treatment method for the metacarpophalangeal and other small joints also.

Pathophysiology

Hand problems can be grouped into seven major categories of disease: congenital, developmental/idiopathic, inflammatory/infectious, traumatic, metabolic, vascular, and neoplastic. There is tremendous overlap between these divisions, and a given disease process may actually have roots in more than one category. However, keeping these major categories in mind and eliminating those that do not fit a patient’s complaint can help narrow down one’s differential diagnosis and arrive at the proper diagnosis and treatment protocol. The remainder of this section reviews the most common disease entities within each category.

Congenital Hand Differences

In the human embryo, the upper extremity begins to develop as a limb bud at 4 weeks after fertilization when a segment of mesoderm outgrows and protrudes into the overlying ectoderm. A small segment of ectoderm then condenses and forms the apical ectodermal ridge, which guides further longitudinal growth of the limb. A second area, named the zone of polarizing activity, forms in the posterior margin of the limb bud and controls radial and ulnar growth and differentiation. A third area in the dorsal ectoderm helps control formation of volar and dorsal characteristics of the limb. From weeks 4 to 8 after fertilization, this small outgrowth of mesoderm becomes a fully differentiated upper extremity with separated joints and digits. It is during this time that most congenital upper extremity anomalies originate.

10. The Hand

391

Failure of Formation of Parts (Arrest of Development)

Failures of formation of parts come in two varieties: transverse and longitudinal. Transverse failures are caused by injuries to the apical ectodermal ridge. They result in complete congenital amputation distal to the site of injury, which can vary from loss of fingertips to complete absence of the arm. The most common presentation is a congenital below-elbow amputation at the level of the proximal third of the forearm; it is treated by fitting a passive mitten when the child is old enough to sit, then a prosthesis a few years later.

Longitudinal failures of formation involve loss of only part of the distal segment. They can be divided into radial (preaxial), central, and ulnar (postaxial). The most common of these are the radial-sided deficiencies such as congenital absence of the thumb or radial clubhand (Fig. 10-1A). These problems are often associated with visceral and bone marrow abnormalities and abnormalities such as Holt–Oram (cardiac septal defects), thrombocytopenia absent radius (TAR), and vertebral, anal, cardiac, tracheoesophageal, renal, and limb abnormalities (VACTRL). These patients should all undergo evaluation by the appropriate pediatric subspecialists. Central defects are much less common and mainly involve the cleft hand. Ulnar-sided deficiencies include ulnar clubhand and its variations; these are often associated with other orthopedic anomalies. A very uncommon form of longitudinal growth arrest involves intrasegmental losses such as phocomelia, in which a relatively normal hand is attached to either the trunk or a very short segment of arm.

Failure of Differentiation (Separation of Parts)

Failure of differentiation occurs when the normal programmed cell death between tissues fails to occur and bones, joints, or individual digits fail to form. The most common manifestation of this is syndactyly, in which individual digits are still linked together, either by webs of skin or sometimes by continued fusion of the bones (see Fig. 10-1C). These parts often require surgical separation when the patient reaches the appropriate age. Other fairly common failures of separation include the congenital lunatotriquetral coalition; this rarely causes any problems and is often an incidental finding. Synostosis, particularly of the proximal radius and ulna, which restricts pronation and supination, and symphalangism, in which there is congenital fusion of the proximal interphalangeal (PIP) joint, are other manifestations that can be more problematic.

Duplication

Duplication or polydactyly, another fairly common congenital hand difference, can range in scope from a simple skin tag attached to the small finger to a complete mirror hand. The very small skin tags formed on the ulnar aspect of the hand can sometimes be treated with suture ligation in the

392 M.A. Haque

A B

C

FIGURE 10-1. Congenital malformations. (A) Radial clubhand produced by longitudinal absence of radius. (B) Failure of formation of parts combined with failure of separation. (C) Simple syndactyly of middle and ring fingers.

nursery, but more complex polydactylies require formal surgical resection and reconstruction. This is particularly true when a joint is involved, as osteotomy to allow the joint surfaces to maintain normal congruity and ligament reconstruction to reestablish stability may be required. Often the

10. The Hand

393

individual duplicated segments are not equal in size to a normal part, and function may not be completely normal after reconstruction. Many of the thumb reconstructions, in particular, require later secondary operations to fine-tune the result or to make adjustments for growth-induced deformities (Fig. 10-2A).

Other Congenital Anomalies

The remaining categories of congenital hand differences are less common. Overgrowth is a condition that can affect either an entire limb or an individual digit or section of the upper extremity (see Fig. 10-2B). When

A B

C

FIGURE 10-2. Congenital and developmental anomalies. (A) Duplication of thumb.

(B) Gigantism of index finger with enlarged soft tissues as well as skeleton. (C) Dupuytren’s contracture. Bands extending from proximal palm into middle segment of finger have caused nearly 90 degree contractures of MCP and PIP joints with dimpling and shortening of skin.

394 M.A. Haque

this is encountered, the physician should look for an underlying cause such as a vascular malformation or neurofibromatosis. The problem can be exceedingly difficult to treat, and when debulking procedures fail, ray amputation of affected digits often is required.

Undergrowth or hypoplasia also shows a wide spectrum of problems including such minor differences as brachymetacarpia (short metacarpals) or involving significant hypoplasias of the entire upper extremity. It is sometimes associated with other syndromic conditions such as Poland syndrome (pectus excavatum and other chest wall abnormalities, hypoplasia of the hand, syndactyly, and other associated abnormalities). The treatment is very patient specific, and often supportive care is all that is needed.

Congenital constriction band syndrome is a process in which the underlying cause is not fully understood. It is thought that amniotic bands form across segments of the extremities, causing deep constriction rings, amputations, or fusions of distal parts. In some rare instances, surgery very soon after birth is required to prevent neurovascular compromise, but most cases this can be treated in a delayed fashion. Treatment often involves excision of the deep constriction band and multiple Z-plasties for reconstruction. In some situations, a separation of distal syndactyly of the digits can be required.

The final category of congenital hand differences involves generalized skeletal abnormalities: these are disease processes such as enchondromatosis, multiple hereditary exostoses, and chondroplasia. Frequently, no hand surgery is required. One should only monitor the patient’s symptoms closely and ensure that they follow up with the appropriate specialists if the symptoms become worse.

Developmental or Acquired Disease

Arthritides

Arthritis of the hand and wrist is a fairly common problem, and as it becomes progressively more severe, patients can experience marked limitation in hand use because of pain or loss of function.

Nearly all types of arthritis eventually affect the hand, but osteoarthritis is by far the most common form that develops. The distal interphalangeal (DIP) joints of the fingers and interphalangeal (IP) joints of the thumbs are the usual sites where this first develops, and patients often notice painless nodules early on in the disease process. Mucous cysts can result at these joints. The PIP joints also become involved and can develop significant angular deformity. The thumb carpometacarpal (CMC) joint, also known as the basilar joint or trapeziometacarpal joint, is a common site of early involvement; it can be extremely painful and cause debilitating loss of pinch and grasp function. In the carpus itself, the scaphotrapeziotrape-

10. The Hand

395

zoid (STT) joint also has fairly high rates of involvement and is often accompanied by thumb CMC arthritis.

The diagnosis can often be made by the patient’s description of their symptoms alone. Physical examination often shows a deformity and nodule formation. Thumb CMC arthritis can further be diagnosed by a positive thumb CMC grind test. The thumb metacarpal is carefully grasped between the examiner’s thumb and index finger. The remainder of the wrist is stabilized with the other hand, and an axial load and circumduction force are applied to the thumb metacarpal. This procedure usually results in severe pain for patients who have arthritis of this joint. Plain radiographs confirm the diagnosis in nearly all cases and advanced imaging is rarely, if ever, needed. Classic radiographic findings are joint space narrowing, subchondral sclerosis, subchondral cyst formation, and osteophyte formation.

Treatment is usually directed by the patient’s level of symptoms and their radiographic staging. For moderate pain and earlier radiographic stages, simple rest and antiinflammatories can often help tremendously. Splinting is often a very usual adjunct, particularly for the thumb CMC joint and for the STT joint. Corticosteroid injections can also give tremendous pain relief, again, particularly at the thumb CMC joint and the STT joint. If patients have significant mucous cysts at the DIP joint causing pain, skin breakdown, or nail deformities, surgical treatment with resection of the mucous cysts and the underlying osteophytes is indicated. More severe PIP and DIP joint involvement causing unremitting pain or deformity is usually treated by a fusion. Joint replacement arthroplasties are available for very limited indications. Isolated STT joint arthritis is usually treated with fusion. Arthritis of the CMC joint can be treated with arthrodesis or arthroplasty using trapezial resection and ligament reconstruction. Some surgeons prefer implant arthroplasties, but these have had problems with stability and wear.

Posttraumatic arthritis is another very common form of arthritis caused by a ligament, cartilage, or bone injury resulting in increased wear of the joint surface and eventual loss of the cartilage space and arthritis formation. One of the most frequently seen forms is the scapholunate advanced collapse pattern or SLAC wrist. The underlying problem here is a rupture of the scapholunate interosseous ligament that goes untreated. The scaphoid eventually assumes a flexed posture and rotates within the scaphoid fossa of the radius, the lunate goes into a hyperextended position, and arthritis develops. This process first starts in the radial styloid region and extends to the entire scaphoid fossa and then to the scaphocapitate interval and eventually around the entire wrist. Treatment options depend upon the stage and include symptomatic treatment initially, followed by scaphoid excision and capitate-hamate-triquetral and lunate fusion, or proximal row carpectomy and total wrist fusion for more-advanced states.

Rheumatoid arthritis has extensive involvement in the hand and wrist (Fig. 10-3). This disease is a systemic problem, and in the hand nearly all tissues can be involved including bone, joint, tendon, and vascular tissues.

396 M.A. Haque

A B

C

D

Соседние файлы в папке Essentials of Orthopedic Surgery, third edition