Essentials of Orthopedic Surgery, third edition / 10-The Hand

The distal radioulnar joint is frequently involved with erosions into the ulnar head, eventually causing instability that allows the ulnar head to abrade the overlying extensor tendons and cause rupture; this is called a Vaughn– Jackson lesion. The remainder of the carpus can develop extensive erosion, frequently causing volar and ulnar subluxation of the carpus on the radius and a radial deviation deformity of the wrist. The thumb CMC joint often erodes and dislocates, pushing the thumb into an adduction deformity. The metacarpophalangeal (MP) joint of the thumb is also frequently involved.

The MP joints of the remaining digits usually drift into an ulnar deviation deformity, further compromising hand function. The PIP joints develop severe synovitis that can lead to either a boutonnière or swan-neck deformity. The DIP joints are usually spared. In the early phases of the disease, treatment is focused on medical management. Accompanying therapy and splinting can be useful adjuncts for maintaining strength and slowing the progress of deformity. As the disease progresses, the individual problems that develop must be addressed. Persistent tenosynovitis is treated with surgical tenosynovectomy; resection of the ulnar head or bony osteophytes at Lister’s tubercle or the scaphoid is also often performed. Rheumatoid destruction of the wrist itself is usually addressed with a fusion. Several types of wrist replacements are available, including Silastic implants and metal and plastic options. The thumb CMC joint is usually addressed with a nonimplant arthroplasty, with trapeziectomy and ligament reconstruction. The MP joint of the thumb is usually fused when necessary, and MP joints of the other digits are either fused or replaced with Silastic or other implant arthroplasties. Fusions and replacements are available for the PIP joints and DIP joints. Many other treatments and surgical options are available. Needless to say, these procedures need to be done by an experienced hand surgeon who can follow the many problems that these patients develop over time.

Nerve Compression Syndromes

Compressive neuropathies of the upper extremity are common problems that cause significant disability and pain in many patients. Carpal tunnel

FIGURE 10-3. Rheumatoid arthritis. (A) Severe erosive destruction of carpal and forearm bones with dislocation of distal radioulnar joint and moderate osteoporosis of all bones. (B) Clinical picture of advanced rheumatoid changes with tenosynovitis at wrist, dislocations of MCP joints of fingers resulting in ulnar drift, and typical deformities of the thumb. (C) Rupture of extensors of ulnar three digits as a result of tenosynovitis at wrist with dislocation of distal radioulnar joint. (D) Results of surgery with relocation of MCP joints of fingers by prosthetic insertion, fusion of thumb joints, and synovectomy of wrist joint and extensor tendons.

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syndrome is by far the most common of these problems. Unfortunately, this condition has received so much attention that people are often labeled with this disease as soon as they present with any hand problems, and the diagnosis can often be faulty. Carpal tunnel syndrome is caused by compression of the median nerve at the wrist underneath the transverse carpal ligament. The hallmark symptoms include numbness, tingling, and paresthesias in a median nerve distribution (the thumb, index, and middle and radial half of the ring finger), loss of dexterity in the hand, and discomfort particularly with wrist flexion or at sleep. In more-advanced stages, patients may develop weakness of the hand and dropping of objects, pain radiating to the elbow or even the shoulder, or atrophy of the thenar musculature.

The underlying cause of carpal tunnel syndrome is unknown in most patients. Patients with metabolic diseases such as hypothyroidism, diabetes, and renal failure are at much higher risk for developing this disease. The relationship of repetitive motion tasks, especially keyboarding, with carpal tunnel syndrome is very controversial, and hand surgeons still debate the causal role of such activities.

Physical examination findings include a positive Tinel’s sign, in which tapping over the median nerve at the wrist crease elicits paresthesias in a median nerve distribution. A positive Phalen’s sign occurs when symptoms are reproduced by holding maximal flexion of the wrist for a minute or less. The carpal tunnel compression test is positive if pressure directly over the carpal tunnel applied by the examiner elicits symptoms within 30 seconds or less. Thumb abduction strength should be tested, and a sensory evaluation should be documented. When patients have an atypical presentation or physical examination, an electromyograph (EMG) and nerve conduction study as well as X-rays can be very helpful for sorting out other diseases or making sure that a more-proximal nerve compression process is not present.

Carpal tunnel syndrome can be treated initially by bracing and oral antiinflammatory medications. If this does not help, a corticosteroid injection into the carpal tunnel gives temporary relief in nearly 80% of patients with true disease. Finally, when conservative measures have failed and the patient has had persistent symptoms for more than 3 to 6 months, a surgical release is indicated. This operation can be done through one of many open techniques or through an endoscopic technique. Overall results are excellent through both methods.

Cubital tunnel syndrome, or compression of the ulnar nerve at the elbow, is the second-most common compressive neuropathy. Patients present with numbness and tingling in the small finger and the ulnar half of the ring finger and frequently complain of elbow pain. Symptoms are often worse at night or after long periods in which the elbow has been flexed. Physical examination findings include a positive Tinel’s sign over the ulnar nerve and behind the medial epicondyle, a positive elbow flexion test in which full flexion of the elbow for more than 30 seconds reproduces symptoms, and in some cases subluxation of the ulnar nerve out of the retrocondylar

groove when flexing the elbow. Distally, one can often find decreased sensation in an ulnar nerve distribution. In advanced cases, weakness to finger abduction or even intrinsic atrophy can be present. Froment’s test, in which the patient is required to pinch a card between the thumb and index finger, is positive when the patient either cannot strongly pinch the card or collapses into a flexed IP joint position and hyperextended MP joint position of the thumb. The main differential diagnosis includes cervical radiculopathy, thoracic outlet syndrome (i.e., brachial plexus compression in the region from the scalenes to the clavicle), and ulnar nerve compression at the wrist. An EMG and nerve conduction study can be helpful to differentiate between these sites, but these are often negative even in moderately advanced stages of cubital tunnel syndrome. Treatment usually starts with extension splinting, activity modification, and antiinflammatories. If symptoms do not resolve in 3 to 6 months or patients begin to develop significant atrophy, an anterior transposition of the ulnar nerve or a medial epicondylectomy may be indicated.

Tendon Compression Syndromes

Stenosing tenosynovitis is the name given to conditions in which tendon segments with a synovial sheath become compressed by the overlying ligamentous or retinacular structures. Patients initially present with pain and eventually develop problems with gliding motion and sometimes even develop frank catching or triggering of the tendon as it passes through its retinacular housing. These problems are frequently associated with diabetes and renal failure. They are sometimes thought to be caused by overuse. Most of the time, however, the underlying cause is unknown. The most common of these tendon disorders is trigger finger, in which the flexor tendons are entrapped underneath the A-1 pulley of the flexor tendon sheath. Patients often develop locking of the finger in flexion, requiring a prying open of the digit with a palpable and sometimes visible pop as the finger fully extends. This condition can be treated with very high success rates with a corticosteroid injection initially. If symptoms recur or do not remit, a surgical release of the A-1 pulley is indicated.

Another very common stenosing tenosynovitis is de Quervain’s tenosynovitis, in which the abductor pollicis longus and extensor pollicis brevis tendons become constricted under the extensor retinaculum at the first dorsal compartment of the wrist; this is especially common in mothers with newborn children. Hallmark physical findings are significant tenderness over the first dorsal compartment at the radial styloid and a positive Finkelstein’s test, in which the thumb and wrist are forcibly maneuvered into ulnar deviation, eliciting severe pain over the first dorsal compartment. Treatment options include nonsteroidal antiinflammatory medications, corticosteroid injections, bracing, which must include the thumb and wrist, and, eventually, surgical release of the first dorsal compartment. Other

ial or cuticle injuries, does lead to a fairly high incidences of infection overall. A paronychia is an infection that affects the soft tissues overlying the proximal nail fold or the lateral edges of the nail (Fig. 10-4A). It is usually caused by Staphylococcus and presents as a red, swollen, painful abscess overlying the nail fold. If it is diagnosed at an early enough stage, warm water soaks and oral antibiotics can cure it. In more-advanced stages, surgical drainage is required.

A felon is a more-involved infection that invades into the pulp of the

fingertip. Patients present with a very swollen, tense, and painful finger pulp (see Fig. 10-4B–D). It is very important to drain this as soon as possible and release all the septa between the skin of the pulp and the bone, thereby completely decompressing the infection. If this is not done, the infection can spread to the bone or to the tendon sheath.

Purulent or septic flexor tenosynovitis is an extremely serious infection that can result in loss of the finger if not treated aggressively. The four

A B C D

E

FIGURE 10-4. Infections of the hand. (A) Paronychia with collection of pus beneath eponychium and base of nail. (B–D) Felon with marked distension of pulp of finger, impending necrosis of skin on palmar surface, and dissolution of bone of distal phalanx. (E) Thenar space abscess.

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classic findings for this are called Kanavel’s signs: fusiform swelling of the digit, severe tenderness over the flexor tendon sheath, semiflexed posture of the digit, and severe pain to passive extension of the digit. This infection should be surgically drained as soon as possible and subsequently treated with several weeks of antibiotics and soaks. If left untreated, it can spread into the palmar bursa and enter the thenar space, the palmar space, or even the carpal tunnel, causing a more severe and widespread infection.

Human bite infections can cause extensive damage before treatment has begun. The injury often occurs in a fight with the patient’s metacarpal head striking a tooth and seeding the MP joint and the metacarpal head with several different bacteria. These wounds should be debrided aggressively and allowed to heal by secondary intent or a delayed primary closure. The antibiotic selected should cover Eikenella corrodens. Dog and cat bite wounds can also cause significant hand infections, including septic flexor tenosynovitis and septic arthritis. Appropriate debridement should be performed when necessary, and antibiotic coverage should include drugs that will eradicate Pasteurella multocida. Infections to the hand and wrist from fungi, mycobacteria, and other atypical flora are relatively rare but should be kept in mind. A history of exposure to soil, birds, or seawater is particularly important to check. These infections often require extensive debridement and long periods of antibiotic therapy.

Trauma

As mentioned earlier, the hand is subject to high rates of trauma, ranging from very minor accidents to devastating injuries to the hand and wrist. It is important for all physicians to have a basic approach to dealing with trauma of the hand and to know when to urgently involve a hand surgeon with these problems.

Lacerations

Lacerations and puncture injuries to the hand can show obvious and extensive injury in some situations, but many of the more subtle small lacerations can also mask significant deep injury. In general, these wounds should not be probed in an emergency room or office setting; all the necessary information can be gleaned by distal evaluation of the affected digit or hand. A careful assessment of nerve, vessel, tendon, ligament, and bone function should be assessed, and plain X-rays should also be taken to ensure that no fracture or residual foreign body is present. Appropriate tetanus and antibiotic coverage should be instituted. If the decision is made to take a wound to the operating room right away, the wound can just be loosely dressed and splinted to await passage to surgery. If the external wound is minor, but the patient needs a tendon or other repair, a loose closure can be performed in the emergency room. Splinting is usually initiated, and the patient

can follow up with the hand surgeon on an elective basis. Minor lacerations that are clean and do not have deep tissue involvement should be definitively closed and dressed in the emergency room. It is important to note here that whenever nerve, tendon, or other significant structural involvement is present, the hand surgeon who will eventually definitively treat this should be contacted so that appropriate care and follow-up can be arranged and the patient does not fall through the cracks or lose an opportunity for timely care. Nerve and flexor tendon injuries, in particular, must be addressed within 1 or 2 weeks to avoid permanent loss of function.

Fractures and Dislocations

Fractures and dislocations of the hand and wrist can occur through a variety of mechanisms, including falls on an outstretched wrist or hand, crush injuries, or direct blows. Appropriate X-rays can usually make the diagnosis, but for some of the carpal injuries in particular, bone scans and MRIs are needed to confirm the problem. Assessment of the fracture should also include whether this is open or if there is associated soft tissue injury involving the nerves, tendons, or vessels. Fractures of the phalanges can involve a variety from simple tuft fractures to extensive intraarticular fractures with comminution. The fractures must be assessed for stability, angular deformity, rotational malalignment, and shortening. If these factors are all found to be acceptable, the fracture can be treated closed with 3 to 4 weeks of immobilization or protected early range of motion until healing occurs. If these factors are not acceptable in the fracture pattern, surgical management should be initiated; the most commonly used fixation techniques involve K-wire or plate-and-screw fixation. This procedure is especially important for intraarticular fractures that are displaced to restore adequate range of motion.

Most metacarpal fractures can be treated nonoperatively. Exceptions include fractures with rotational malalignment, excessive angular deformity, or intraarticular displacement, especially of the thumb or small metacarpal bases. Fractures of the thumb metacarpal base often occur in a pattern in which the ulnar segment of the base stays attached to the trapezium and index metacarpal through the volar oblique ligament and the remainder of the metacarpal shaft subluxates radially. This pattern is called a Bennett’s fracture and often requires fixation. Boxer’s fractures are small metacarpal neck fractures that are extremely common. If no rotational deformity is present, up to 70 degrees of apex dorsal angulation can be treated nonoperatively in most cases. Index and middle metacarpal neck fractures are more problematic as their metacarpal bases are quite stiffly attached to the carpus and less compensation can occur.

Carpal bone fractures occur frequently as well. The most commonly injured wrist bone is the scaphoid (Fig. 10-5). When patients are tender over the anatomic snuff box or the scaphoid tubercle, one should maintain

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A B

FIGURE 10-5. Fracture with nonunion of carpal scaphoid. (A) Established nonunion with sclerosis and cyst formation 6 months after untreated “wrist sprain.”

(B) Operative treatment with screw resulted in union.

a high index of suspicion for this fracture. If initial X-rays are negative, advanced imaging techniques such as bone scan or MRI should be obtained, or the patient should be immobilized for 3 weeks and repeat radiographic views considered. Scaphoid fractures have high rates of complications because of the poor vascularity of this bone; nonunions and avascular necrosis of the proximal pole can occur, especially when treatment is delayed or missed. Another common carpal fracture is the dorsal triquetral avulsion injury, which often occurs after a fall on an outstretched wrist; this is best seen on lateral radiographic views in which a small fleck of bone is noted dorsal to the triquetral region. Immobilization in a cast or brace for 3 to 4 weeks usually results in a very good outcome.

Dislocations of the interphalangeal joints are quite common and can usually be reduced using closed techniques. It is important to initiate early range of motion soon after this to avoid excessive stiffness. It is particularly important to do brief periods of extension splinting, once the joint is stable enough, to prevent flexion contractures from developing. At the MP joints, dislocations can result in irreducible situations in which the volar plate becomes incarcerated between the articular surfaces. This situation requires surgical treatment, but again, nearly always excellent stability can be expected once reduction is obtained. Here, too, it is very important to initiate range-of-motion exercises soon after surgical treatment to avoid subsequent stiffness. Injuries to the collateral ligaments of the PIP and MP joints are common, especially at the thumb. An injury to the thumb MP joint ulnar collateral ligament is often called a “gamekeeper’s” or “skier’s” thumb and is a frequent athletic injury. Patients who have tenderness over the ligament, but good stability, should be immobilized for 3 to 4 weeks, and then

range of motion should be initiated. If the patient has more than 45 degrees of opening to radially directed stress, or more than 50% subluxation of the joint on stress views, or has a palpable Stener’s lesion (a completely ruptured ulnar collateral ligament that is incarcerated in the adductor pollicis muscle), surgical repair of the ligament is indicated. It is also important to note that sprains and strains of the PIP joints can result in very long periods of swelling and stiffness of the joint and, in some patients, can lead to some permanent thickening of the collateral ligaments.

Severe and Complex Upper Extremity Injuries

Amputations of portions of the upper limb, especially the fingers, are very common especially in industrial and agricultural environments. Modern microvascular surgical techniques allow reimplantation of the amputated parts in many situations. The severed part should be wrapped in a gauze dressing soaked in sterile saline and placed in a container or sealed plastic bag that can be immersed in ice and transported to a treating facility. The part should never be placed directly on ice, and dry ice should never be used. An experienced hand or reimplantation surgeon should be consulted immediately to assess whether the part is a good candidate for reattachment. Typical indications at this time include any part that is large enough in a child, the thumb at any level that can be reattached, multiple digits, or an amputation through the midpalm or proximal. Severe contamination, crush injury, avulsion, or broad areas of vascular damage are contraindications to reimplantation of the part.

Extensive mangling injuries must be treated by an experienced hand surgeon as soon as possible. Initial care rendered often determines the final outcome and, therefore, must be carefully planned with a long-term treatment plan and an outcome firmly in mind. Inadequate debridement, primary closure, improper splinting, and nominal or poor understanding of the injury all too often result in more significant disability than necessary.

Crush injuries and high-energy trauma should always be carefully evaluated for the development of compartment syndrome. The early symptoms may be very subtle. The history may be vague, for example, an intoxicated patient sleeping on an arm for a long period of time (and the damage may take a long time to develop). Iatrogenic causes include cast or dressings that are too tight or extravasation injuries. One should maintain a high degree of suspicion for this problem and observe for the five P’s: pain out of proportion to the injury, severe pain with passive stretch, later paresthesias, pallor, and pulselessness. The condition occurs from increased pressure in the forearm or hand muscle compartments preventing flow through the venules and capillaries and preventing perfusion of the soft tissues of the compartment. Compartment pressures can be measured, but determining the threshold pressure at which to release the compartments is not always easy.

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When this diagnosis is confirmed, it constitutes a surgical emergency. It is imperative to take the patient to the operating room and release the compartments as soon as possible to prevent necrosis of the muscle and other tissues, resulting in severe patterns of function loss, such as a Volkmann’s contracture.

Thermal, chemical, or electrical injuries cause soft tissue problems of varying depth. The skin is the initial point of contact and may show firstdegree (redness), second-degree (blistering), or third-degree (full-thick- ness or charring) injuries, particularly with burns. Early care of the second-degree injury can minimize the chance of an infection converting it to a third-degree injury. Early referral to a hand therapist for exercise and splinting may avoid extensive late contractures. Third-degree burns should be treated by early surgical excision of the eschar and skin grafting. Chemical injuries should be treated in a facility that has experience in managing these conditions as specific antidotes can be used to neutralize many chemicals and minimize damage.

Cold injury varies from minor frostbite to extensive freezing of tissues and peripheral parts. The initial treatment should involve rapid rewarming of the area of frostbite followed by observation to see what survives. Early amputation is not necessary in the absence of infection. Electrical burns can be quite deceptive as to the extent of damage and require repeated evaluation.

Other Injuries

Mallet finger may occur from rupture of the terminal extensor tendon, often with trivial injury. Fracture of the dorsal lip of the distal phalanx may be seen on X-ray in some cases. Full passive extension is present, but active extension is not. Treatment usually involves splinting in full extension for 6 or more weeks.

Boutonnière deformities occur from disruption of the central slip of the extensor tendon over the PIP joint by blunt trauma or laceration. Over time, the lateral bands slip progressively volar to the axis of rotation of the PIP joint, especially if the triangular band is disrupted. The patient develops a flexion deformity at the PIP joint and compensatory hyperextension at the DIP joint. When diagnosed early, this can be treated with closed extension splinting of the PIP joint. After prolonged presence of deformity, surgical treatment can be required.

Metabolic Disease

Many metabolic illnesses such as diabetes, hyperthyroidism, hyperparathyroidism, and renal failure can be underlying causes to hand problems such as carpal tunnel syndrome. One should be careful to check a patient’s medical history and make sure these underlying problems are adequately treated before initiating any surgical intervention.