40 Wrist pain Functional anatomy of the wrist \200 The wrist includes radiocarpal (scaphoid and lunate) and intercarpal articulations. The ulna does not truly articulate with the luna te but is joined to it, the triquetrum, and the radius (ulnar side of distal aspect), by th e triangular \201 brocartilage complex. The intercarpal joints are joined by intercarpal ligaments and are most stable when the wri st is in full extension. The anterior carpal ligaments are stronger than the posterior ones and are reinforced by the \202 exor retinaculum. Wrist and \201 nger \202 exor tendo ns, the radial artery, and the median nerve enter the hand in a tunnel formed by the carpal bones and the \202 exor retinaculum (carpal tunnel). Flexion (70 ), extension (70 ), radial and ulnar deviation (about 20 and 30 from midl ine, respectively) occur at the wrist but supination/ pronation of the wrist and hand is du e to radiohumeral movement at the elbow. The \202 exor carpi radialis (FCR) and ulnaris (FCU) are the main \202 exors of the wrist, although the palmaris longus (pl) also helps (see Figure 2.6). All arise from the medial humeral epicondyle. \200 All carpal extensors arise from the lateral humeral epicondyle (see Figure 2.7). Radial deviation (abduction) occurs primarily when radial \202 exors and extensors act to gether. Ulnar deviation (adduction) occurs primarily when ulnar \202 exors and extensors act together. Taking a history Table 2.4 details the major diagnoses for painful conditions of the wrist and hand. Determine the exact location of the pain \200 Pain localizing only to the wrist most like ly comes from local tissue pathology. Cervical nerve root pain as a result of a C6, C7, or C8 lesion and pain from peripheral nerve lesions is likely to be located chie \202 y in th e hand. Pain at the base of the thumb, aggravated by thumb movements, in middle and old age is typi cal of OA (see Chapter 6) of the trapezium- \201 rst metacarpal joint. Pain in this area m ight also be due to tenosynovitis of thumb tendons. Trauma history \200 Injury/post-injury conditions are common. A history of trauma is important. Common fractures in adults are: scaphoid and base of the \201 rst metacarpal (Bennett \200\231s), and head of the radius (Colles \200\231). \200 Distal rad ioulnar physeal injuries may occur in children. \200 Posttraumatic chronic wrist pain fol lowing injuries may be due to ligamentous injury and chronic carpal instability or osteonec rosis (lunate). WRIST PAIN 41 (a) Digital flexor tendon sheaths Flexor pollicis longus tendon sheath Common flexor tendon sheath Flexor retinaculum Flexor digitorum superficialis and flexor digitorum profundus tendons Flexor carpi radialis tendon sheath Extensor digitorum communis and extensor indicis propius (fourth compartment) (b) Extensor digiti minimi (fifth compartment) Extensor pollicis longus (third compartment) Extensor pollicis brevis and abductor pollicis longus (first compartment) Extensor carpi ulnaris (sixth compartment) Extensor carpi radialis longus et brevis (second compartment) Extensor retinaculum Fig. 2.7 Flexor (a) and extensor (b) tendon sheaths crossing the wrist. Flexor carpi radial is (FCR) inserts into the second and third metacarpals. Flexor carpi ulnaris (FCU) inserts into the pisiform, hamate, and \201 fth metacarpal. Extensor carpi radialis longus (ECRL) inserts into the base of the second, extensor carpi radialis brevis (ECRB) into the third, and extensor carpi ulnaris (ECU) into the \201 fth metacarpal, respectively. CHAPTER 2 Regional musculoskeletal conditions 42 Table 2.4 Painful conditions of the wrist and hand: major diagnoses Articular disorders In \202 ammatory arthritis (e.g., RA, JIA) Degenerative arthritis* Crystal arthritis Ligamentous lesions* Carpal instability (e.g., lunate dislocation) Periarticular disorders De Quervain \200\231s tenosynovitis Tenosynovitis of common \202 exor/extensor tendon sheath Flexor pollicis tenosynovitis Distal \202 exor stenosing tenosynovitis (trigger \201 nger or thumb)* Ganglia*, subcutaneous nodules, tophi Diabetic cheiroarthropathy Dupuytren \200\231s contracture* Bone pathology Fracture* Neoplasia Infection Osteochondritis (lunate \200\224Kienb ck \200\231s; scaphoid \200\224 Prieser \200\231s) (see Chapter 16) Neurologic Median nerve entrapment (carpal tunnel* or at pronator teres) Anterior interosseous nerve syndrome Ulnar nerve entrapment (cubital tunnel or in Guyon \200\231s canal in wrist) Posterior interosseous nerve entrapment Radial nerve palsy Brachial plexopathy Thoracic outlet syndrome Cervical nerve root irritation or entrapment* Complex regional pain syndrome (see Chapter 18) Spinal cord lesions, e.g., syringomyelia Common conditions. Unusual or \202 orid pain descriptors suggest a regional pain syndrome (e.g., re \202 ex sympathetic dystrophy). Following trauma, regional pain syndromes are not uncommon in chil dren, adolescents, or young adults. Are there features to suggest synovitis? \200 Pain due to wrist joint synovitis may be as sociated with stiffness and be worse at night or in the early morning. Stiffness in the han d may WRIST PAIN 43 have various causes, but these will include multiple tendon/small joint synovitis, diabetic cheiroarthropathy, or even scleroderma (see Chapter 12). Wrist synovitis occurs commonly in adult RA and in children with both systemic and rheumato id factor positive JIA. It occurs in 5% of oligoarticular JIA cases (see Chapter 7). In the elderly, wrist synovitis may be due to calcium pyrophosphate dihydrate (CPPD) crystals (see Chapter 15). The quality of the pain \200 Although primary bone pathology is rare, local bony pain (un remitting, severe, preventing sleep) might suggest avascular necrosis in those at risk or, if part of a wider pattern of bony pain, metabolic bone disease (e.g., physeal pain in chil dren with rickets). Radicular pain may be burning in quality and is typically associated with numbness and pare sthesias. Such neurogenic pain is commonly due to nerve root irritation or compression. Other joint/musculoskeletal symptoms \200 Wrist and extensor tendon sheath synovitis is a common presenting feature of adult RA. Other joints may be affected. CPPD arthritis commonly involves the wrist and can mimic RA in its joint distribution and presentation in the elderly. Wrist synovitis and enthesitis occur in SpA. Pain may be considerable, although swelling is minimal. There may be in \202 ammatory-type symptoms of spinal pain a nd enthesitis elsewhere. Ask speci \201 cally about job/leisure activities \200 Repetitive lateral and medial wri st movements with thumb adducted can cause tenosynovitis of the abductor pollicis longus (A PL) or the extensor pollicis brevis (EPB), commonly called De Quervain \200\231s tenosynovi tis. If there is no obvious history of trauma, tendonitis may be a presenting feature of a systemic autoimmune rheumatic disease or even gonococcal infection in adolesce nts and young adults. Overuse pain syndromes may occur as a result of repetitive activity. The term repetitive st rain injury is controversial. Objective assessment of pain, location of swelling, etc., fro m the outset is invaluable in assessing the response to treatment. Lack of objective \201 ndings (if imaging is normal) suggests a regional pain disorder. Examination Visual inspection Inspect the dorsal surface of both wrists looking for swellin g, deformity, or loss of muscle bulk. \200 Diffuse swelling may be due to wrist or extens or tendon sheath synovitis. A prominent ulna styloid may result from subluxation at the distal radioulnar joint due to synovitis or radioulnar ligament damage. \200 Prominence ( \200\234squaring \200\235) of the trapezoid \200\223 \201 rst metacarpal joint commonly occurs in OA of this joint. CHAPTER 2 Regional musculoskeletal conditions 44 Loss of muscle bulk in the forearm may be due to a chronic T1 nerve root lesion or disuse atrophy. Flexion/extension range tests for major wrist lesions \200 The normal range of both \202 exion and extension in Caucasian adults is about 70 . Synovitis invariably reduces this range. When wrist synovitis is present, swelling on the dorsum of the wrist may become more appare nt. Substantial common \202 exor or extensor tendon swelling will probably also block the full range of wrist movement (soft tissue approximation \200\234end-feel \200\235). There is normally an additional 20 of \202 exion and extension to the active range with passive movement. Elicited pain and crepitus are unlikely to be speci \201 c for any type of lesion but may draw your attention to the anatomical site of the lesion. Examine the dorsum of the wrist in detail \200 Note any abnormal excursion of the ulnar s tyloid associated with pain and/or crepitus suggesting synovitis. Posttraumatic carpal instability, particularly scapulolunate dissociation, is relatively co mmon. The latter is demonstrated by eliciting dorsal subluxation of the proximal scaphoid p ole by \201 rm pressure on its distal pole as the wrist is deviated radially from a start ing position with the forearm pronated and the wrist in ulnar deviation. Note any gap betwe en the scaphoid and lunate and any associated tenderness. \200 Note any tenderness or thi ckening of the common extensor tendon sheath and tendon sheath of APL and EPB. Tenderness at the base of the thumb may be due to wrist synovitis, carpal or carpometacarpal OA, tenosynovitis, a ganglion, or a ligament lesion. Finkelstein \200\231s test for De Quervain \200\231s tenosynovitis may be used to elicit APL/EPB tendon pain. With the thumb adducted and opposed, the \201 ngers are curle d to form a \201 st. Passive ulnar deviation at the wrist stretches the abnormal tendons and elicits pain. Although it is a sensitive test, it is not speci \201 c for tendon pain. In adults, protrusion of the thumb out of the \201 st on the ulnar side of the hand durin g the \201 rst part of this test is unusual and suggests hypermobility. Test the integrity of the tendons Many muscles/tendons that move both the wrist and digits originate at the elbow; therefore, the quality of information gained from isolated tendon r esistance tests (for either pain or strength) may be affected by pain else- where around th e wrist, wrist deformity, or elbow lesions. Interpret \201 ndings cautiously. Useful information might be obtained by passive movemen t of a tendon rather than by resisted active movement, and also by feeling for thickening o r crepitus of the tendons. Diagnosis and treatment The diagnosis and treatment of wrist conditions is covered in the f ollowing section on symptoms in the hand. This page intentionally left blank CHAPTER 2 Regional musculoskeletal conditions 46 Symptoms in the hand Symptoms in the hand are a common presenting feature of some systemic conditions, and localized neurologic and musculoskeletal lesions are com- mon, especially i n adults. Detailed knowledge of anatomy is beyond the scope of this text. Functional anatom y is important and the more common abnormalities are summarized in the subsections that fol low. Functional anatomy of the hand The long tendons \200 Digital power is provided primarily by \202 exor and extensor muscles arising in the forearm. Their action is supplemented an d modi \201 ed by small muscles in the hand. Precise movements of the hand are mainly due to small muscles. Powerful digital \202 exors (see Figure 2.7): \202 exor digitorum super \201 cialis (FDS), \202 exor digitorum profundus (FDP), and \202 exor pollicis longus (FPL). fds \202 exes proximal interphalangeal joints (PIPs) and, more weakly, metacarpophalangeal joints (MCPs)/wrist. fdp \202 exes distal interphalangeal joints (DIPs) and, increasingly weakly, PIPs, MCPs/wrist. FPL \202 exes (at 90 to other digits) mainly the PIP but also the whole thumb in a power grip (see below). Powerful digital extensors (see Figure 2.7): the extensor digitorum (ED) arises from the la teral epicondyle splitting at the wrist to insert into each digital dorsal expansion (digit s two to \201 ve) that attaches to all three phalanges (see Figure 2.8). The \201 fth d igit has an additional tendon, extensor digiti minimi (EDM) that also arises at the lateral epicondyle. APL abducts the thumb at the mcp provided the wrist is stable. \200 EPB and EPL extend th e thumb. \200 Extensor indicis (EI) arises from the ulna posterior border distal to EPL and joins the index \201 nger ed tendon. The muscles of the thenar eminence (see Table 2.5) act synchronously. All except adductor p ollicis (ulnar nerve, C8/T1) are supplied by the median nerve from C8/T1 nerve roots. All t hree muscles are supplied by the ulnar nerve (C8/T1). The intrinsic muscles \200 The longitudinal muscles of the palm (four dorsal and four pal mar interossei and four lumbricals) all insert into digits. Palmar interossei, from metacarpals 1, 2, 4, and 5, insert into dorsal tendons. Each dorsal interosseous arises from origins on two adjacent metacarpals. The muscles abduct the second and fourth \201 ngers and move the middle \201 nger either medially or laterally. The four lumbricals (see Figure 2.7, Table 2.6) arise from tendons of FDP in the palm passi ng to the lateral side of each MCP inserting into the dorsal expansions. The interossei combine with lumbricals to facilitate \201 ne control of \202 exion and extension of MCPs and PIPs. SYMPTOMS IN THE HAND 47 Distal interphalangeal joint Collateral (side) slips Proximal interphalangeal joint Intermediate (central or median) slip Dorsal (extensor) expansion (hood) Metacarpophalangeal joint Interosseous tendons Lumbrical tendon Extensor digitorum communis tendon Metacarpal Fig. 2.8 Extensor expansion of a \201 nger. Table 2.5 Muscles of the thenar eminence Muscle Origin Insertion Abductor pollicis brevis Flexor retinaculum, scaphoid, and trapezium Thumb proximal phalanx and dorsal expansion Flexor pollicis brevis Flexor retinaculum, trapezium, trapezoid, and capitate Thumb proximal phalanx (base of radial side) Opponens pollicis Flexor retinaculum and tubercle of the trapezium First metacarpal (lateral border) Adductor pollicis Capitate, bases of second/ third metacarpals and distal third metacarpal Thumb proximal phalanx (medial side) CHAPTER 2 Regional musculoskeletal conditions 48 (a) Third lumbrical First lumbrical Opponens pollicis Abductor pollicis Abductor digiti minimi Lexor pollicis brevi Abductor pollicis brevis Flexor digiti minimi Flexor retinaculum (b) Second dorsal interosseus Third dorsal interosseus Forth dorsal interosseus First dorsal interosseus Fig. 2.9 (a) Lumbrical muscles and muscles of the thenar and hypothenar eminences. (b) Dors al interossei. SYMPTOMS IN THE HAND 49 Table 2.6 Muscles of the hypothenar eminence Muscle Origin Insertion Base of the \201 fth proximal phalanx and dorsal expansion Abductor digiti minimi Flexor retinaculum (FR), pisiform, and pisohamate Ligament Flexor digiti minimi brevis Flexor retinaculum and hook of hamate Base of the \201 fth proximal phalanx Opponens digiti minimi Flexor retinaculum and hook of hamate Medial side of the \201 fth Metacarpal Grip \200 For power, the wrist extends and adducts slightly, and the long digital \202 exors contract. A modi \201 ed power grip, the hook grip, is used to carry heavy objects like a suitcase. The thumb is extended out of the way and extension at MCPs accompanies \202 exion at PIPs/DIPs. More precision in the grip can be obtained using varying degrees of thumb adduction, abduction, and \202 exion. The thumb can be opposed with any of the four other digits depending on the shape of the object to be held and the type of manipulation required. Taking a history A history of acute or overuse trauma with subsequent localized symp- toms requires a straightforward application of anatomical knowledge, precise examination, and ju dicious choice of imaging techniques for diagnosis. However, there are more subtle or less easily delineated pat- terns of symptoms in the hand, particularly when pain is diffuse or poorly localized. Is the pain associated with immobility or stiffness? \200 Stiffness may be associated wit h joint or tendon synovitis but is not speci \201 c. Prompting may provide more accurate localization of symptoms. If unilateral, especially on the dominant hand, remember that diffuse hand pain may be due to a regional pain syndrome. Is stiffness local or diffuse? \200 Patterns of joint involvement in autoimmune rheumatic disease and polyarticular arthritis are summarized in Chapter 3. If localized in the palm, look for evidence of a Dupuytren \200\231s contracture (associate d with diabetes). If diffuse, there may be thickening of soft tissue from a systemic proces s, e.g., hypothyroidism, scleroderma, diabetic cheiroarthropathy, or disorders of mucopolys accharide metabolism (the latter especially in infants, although Fabry \200\231s syndrome c an present in adulthood, and is associated with acroparesthesias and palmar telangiectasias ). CHAPTER 2 Regional musculoskeletal conditions 50 Stiffness due to an upper motor neuron lesion (an interpretation of increased tone) is unli kely to be con \201 ned to the hand and is likely to be associated with weakness. The patt ern of symptoms over time should give a clue to its etiology. Are there neurologic qualities to the pain or characteristics typical of a common nerve les ion? \200 \200\234Burning \200\235 or \200\234deep \200\235 episodic pain varying with head, neck, and upper spinal position is typical of cervical nerve root pain. Ask about occupation and othe r activities that are associated with neck problems, the relationship with sleep posture, a nd frequent headaches. \200 Pain on the radial side of the hand waking the patient at nig ht and often relieved, at least partially, by shaking the hand is typical of median nerve e ntrapment in the wrist. However, pain in this condition is often poorly localized at initia l presentation, and may be described as \200\234hand swelling \200\235. Remember other les ions that produce pain in the area around the thumb base: trapezoid \200\223 \201 rst meta carpal joint OA, tenosynovitis of APL/EPB (De Quervain \200\231s) or EPL, referred pain fro m a C6 nerve root lesion, and ligament lesions (e.g., ulnar collateral ligament of \201 r st MCP \200\224 \200\234skier \200\231s thumb \200\235). Tingling/pins and needles/numbness Make sure both you and the patient understand what you e ach mean by these terms. \200 Symptoms usually denote cervical nerve root or peripheral n erve irritation/compression, although they can re \202 ect underlying ischemia. Tingling in the \201 ngertips of both hands, however, is recognized to occur commonly in patients diagnosed with \201 bromyalgia. Symptoms associated primarily with speci \201 c positions of the whole arm may be due to t horacic outlet compression of neurovascular structures. Pain arising from bone Pain in the hands arising from bones may be dif \201 cult to discri minate. Radiographs will often lead to con \201 rmation of the diagnosis. \200 The most common tumor in the hand is an enchondroma. It is usually painless. If they are painful, th en one should suspect infarction or malignant change. Secondary metastases and malignant bone tumors in the hand are rare but must be ruled out i n children, adolescents, and young adults with persistent localized bone pain. Paget \200\231s disease of hand bones can occur but is relatively rare. \200 Digital bone pain from osteomalacia/rickets occurs but is unusual at presentation. Digital pain may rarely be due to sarcoidosis, hyperparathyroid bone disease, thyroid acrop achy, hypertrophic pulmonary osteoarthropathy (HPOA), or pachydermoperiostitis. Look for cl ubbing. Ischemic pain? A history suggestive of ischemic pain in the hands is rare in rheumatologic practice. Persistent ischemic digital pain is a medical emergency. SYMPTOMS IN THE HAND 51 Digital vasomotor instability (e.g., Raynaud \200\231s phenomenon [RP]) is episodic and tri ggered by cold and emotion, and characterized by digital color changes: white/blue then red . Pain from vasculitis is likely to be persistent and associated with a purpuric rash, nail-fold infarcts, or splinter hemorrhages. Ischemic pain associated with cervicothoracic posture or prolonged arm elevation maneuvers may be due to thoracic outlet syndrome. Pain may be due to thromboembolism (e.g., antiphospholipid syndrome), infective endocarditis, or thromboangiitis obliterans (Buerger \200\231s disease ). Swelling Examination is more reliable than a history. \200 Apart from isolated lesions su ch as ganglia, patients \200\231 description of soft tissue or joint swelling may be unreli able and should be substantiated by examination. Nerve lesions can give the impression that swelling is present (think what a dentist \200\231s local anesthetic does for your lip!). Patients with carpal tunnel syndrome, for example, frequently complain of hand swelling at night. Weakness Ask about trauma, neck, and median nerve entrapment symptoms. \200 Acute tendon injuries are common industrial accidents. Chronic occupational overuse may also lead to rupture. If weakness is profound and there has been no obvious trauma, the cause is likely to be neuromuscular. If not associated with pain, weakness is more likely to be neurologic than musculoskeletal in origin. Weakness associated with pain may be due to a neurologic or musculoskeletal lesion, the latter situation often due to an inability to use the hand (or part of it) because of pain or an alteration in biomechanical function as a result of defor mity, which may only be slight. True weakness associated with stiffness is associated with myelopathy or even motor neuron disease. A detailed history of the progression of symptoms is important and neurologic exam ination should be thorough. Trigger \201 nger This may denote stenosing tenosynovitis of a digital \202 exor tendon . Damage to the tendon and its sheath can result in a \201 brous nodule attached to the t endon that moves and catches under the proximal annular ligament just distal to the MCP. It may not be painful. This most commonly affects middle and ring \201 ngers and is prevale nt among professional drivers and cyclists, and those in occupations requiring repeated use of hand-held heavy machinery. Examination The sequence described here is comprehensive but should be considered if a gene ral condition is suspected. Often an examination only needs to be more speci \201 cally di rected. CHAPTER 2 Regional musculoskeletal conditions 52 Inspection of the nails and \201 ngers \200 Pits/ridges are associated with psoriatic a rthritis (see Plate 3). \200 Splinter hemorrhages may be traumatic but are associated wit h infective endocarditis or vasculitis. Obvious cuticle damage and punctate cuticle erythema (dilated capillary loops) are features of secondary Raynaud \200\231s phenomenon, scleroderma, or my ositis (see Plates 4, 20, 21). Periungual erythema is associated with a number of autoimmune rheumatic and connective tissue diseases. Multiple telangiectasias are associated with limited cutaneous scleroderma (see Chapter 13). Diffuse \201 nger thickening (dactylitis) may be due to gross tendon thickening (e.g., SpA or sarcoid, see Plate 19), or connective tissue \201 brosis/thicken ing (scleroderma, cheiroarthropathy). Bony or soft- tissue DIP or PIP swelling should be di scriminated. A shiny/waxy skin appearance, often pale, may indicate scleroderma. \200 Scattered, tiny, nonblanching dark red punctate lesions are typical of cutaneous skin vasculitis. Erythematous or violaceous scaly papules/plaques over MCPs or PIPs may suggest dermatomyositis. Note any diffuse swelling of the hand \200 Diffuse soft-tissue or skin swelling may occur in association with RA, RS 3 PE syndrome, JIA, complex regional pain syndrome (see Plate 5 ), and scleroderma. RS 3 PE (remitting seronegative symmetric synovitis with pitting edema), which presents mai nly in adults in their 70s, may be a distinct type of nonerosive polyarticular/tendon synov itis but may be associated with other, often hematologic, conditions. Swelling associated with complex regional pain syndrome may be localized or diffuse (see Plate 5). Skin may be shiny, and later there is often a dark red or blue mottled appearance. Typical skin appearances are critical to making a clinical diagnosis of scleroderma. The sk in may be initially puffy but later shiny and tight and, with progression, atrophic with co ntractures. Note any muscle wasting Wasting may be due to a degree of chronic denervation (e.g., the th enar eminence in CTS), disuse atrophy (e.g., painful polyarthropathy, joint hypomobility), or catabolism of muscle (e.g., polymyositis, RA). In the eld- erly there may be age-related muscle loss ( \200\234sarcopenia \200\235). Note any deformity of digits \200 Deformities tend to occur with long-standing polyarticu lar joint disease, e.g., OA, severe RA, and psoriatic arthritis. Isolated deformities may be due to previous bone or tendon trauma, severe neurologic lesions and Dupuytren \200\231s contracture. A mallet \201 nger (loss o f active DIP extension) is due to rupture of the distal extensor tendon expansion usually d ue to direct trauma. SYMPTOMS IN THE HAND 53 Inspect the palm and dorsum of the hand \200 Palmar erythema is not speci \201 c but is associated with autoimmune disorders of connective tissue and joints. Check for Dupuytren \200\231s contracture (fascial thickening on ulnar side). \200 On the dorsum of the hand, ganglia and swelling of the common extensor tendon sheath are usually easily noted. Swelling of the extensor tendon sheath is commonly associated with RA in adul ts. Palpation of joints and nodules Palpation of joints and nodules is best done using thumb pa ds with the patient \200\231s wrist supported. \200 Swelling should be noted for site, co nsistency, tenderness, and mobility. Osteophytes and exostosis are periarticular or at sites of pressure, may be tende r, but are always \201 xed (see Plate 16d). \200 Ganglia are hard and usually quite mob ile (can occur anywhere). \200 Rheumatoid nodules occur anywhere but typically are found on the dorsum of the hand and the extensor surface of the elbow; tophi (usually distal) are rubbery, hard, relatively \201 xed, but may be moved (see Plate 16a). Synovitis is often represented by soft ( \200\234boggy \200\235), often springy, swelling a round a joint. It may be tender and warm but this is not invariable. Synovitis in a single joint may be due to autoimmune rheumatic disease, oa, infection, or f oreign-body synovitis (e.g., rose thorn synovitis). Palpate tendons in the palm or on the volar aspect of the phalanges \200 Thickening, tend erness, and crepitus suggest tenosynovitis but tenosynovitis can be hard to spot if it is mild. Tethering and thickening of tendons in the palm associated with excessive digital \202 exion when the hand is at rest and a block t o passive \201 nger extension suggests chronic \202 exor tenosynovitis (take care to no te any contributory joint damage). Passive tendon movement by gently \202 exing/extending a proximal phalanx may disclose pa lpable tendon nodules, crepitus, and tenderness. Discriminate Dupuytren \200\231s contracture from \202 exor tendonopathy Dupuytren \200 \231s contracture typically involves the fourth and \201 fth \201 ngers (40% bilateral) . It is common in males aged 50 to 70. The fascia extends to the second phalanx, thus, if s evere, the condition causes \201 xed \202 exion of MCPs and PIPs. It is associated with epilepsy, diabetes, and alcoholism, and usu- ally is not painful. Diagnostic tests for hand and wrist disorders Radiographs \200 An AP view of the hand and wrist is a useful screening tool to characterize a polyarthropathy and diagnose traumatic or metabolic bone lesions (see Table 2.7). Radiographs may reveal soft tissue swelling around joints compatible with a diagnosis of synovitis. CHAPTER 2 Regional musculoskeletal conditions 54 Table 2.7 Some conditions/features that may be diagnosed on simple AP hand/wrist radiograph s Bone conditions Fractures (e.g., scaphoid, base of \201 rst metacarpal) Tumors Metabolic bone diseases (e.g., rickets, hyperparathyroidism) Avascular necrosis (e.g., posttraumatic \200\224lunate, sickle cell disease) Sarcoidosis (may also have arthropathy) Speci \201 c features Cartilage damage (joint space loss and subchondral bone changes) Articular erosions Osteophytes Infection (cortex loss, patchy osteolysis) Calcium deposition in joint (e.g., triangular ligament chondrocalcinosis) Soft tissue swelling (e.g., over ulnar styloid in wrist synovitis) Periarticular osteoporosis (associated with joint in \202 ammation) Carpal dislocation (e.g., lunate displacement in chronic carpal pain) Polyarticular/ overall patterns of radiological abnormality OA (distribution of osteophytes and subchondral bone changes) RA, JIA (e.g., deformities, erosion appearance/distribution) Psoriatic arthritis (e.g., deformities, erosion appearance \200\224DIPs) CPPD arthritis/gout (e.g., erosion appearance in gout) Radiographs are insensitive for identifying erosions in early autoimmune joint disease. An oblique view of the hand may add information about joint erosions if an erosive MCP arthritis is considered. Lateral and carpal tunnel views of the carpus can be obtained by varying the degree of X-ra y projection angle; however, unless searching for evidence of fracture these views are rare ly needed. Further imaging: US, MR, and bone scan \200 In experienced hands, US can be a useful way of looking for early synovitis and patterns of abnormality in association with median nerve entrapment. MR may demonstrate a torn or avulsed triangular cartilage in patients with a posttraumatic painful wrist or with carpal instability. SYMPTOMS IN THE HAND 55 MR images of the carpal tunnel are especially useful in con \201 rming median nerve compression/tethering and soft tissue wrist pathology, particularly when sympt oms recur after carpal tunnel release surgery. \200 MR can provide valuable information a bout the degree and distribution of in \202 ammatory disease in joints and tendons, partic ularly in children and patients with whom history and examination are dif \201 cult. MR is more sensitive than radiography in identifying joint erosions in RA. Choosing MR over US depends on availability and sonographer experience. Bone scan is not speci \201 c for any single condition, but in young adults (after closure of epiphyses and before OA is likely) it may be useful for disclosing patter ns of in \202 ammation at and around joints. 99m Tc-labeled human immunoglobulin may be mo re speci \201 c for detecting patterns of synovitis in children and adults. Laboratory tests \200 CBC, ESR, CRP. The characteristic, though nonspeci \201 c, picture in patients with a systemic in \202 ammatory condition such as RA or polyarticular JIA, is mild anemia with normal red cell indices, high or high-normal platelets, and increased acu te phase response. Lymphopenia frequently accompanies autoimmune disease. Neutrophils are r aised in infection, with steroids, and in systemic JIA or adult onset Still \200\231s disea se. Blood urea, electrolytes, creatinine, and urate will detect hyperuricemia and renal impairm ent associated with gout (see Chapter 15). Blood calcium, phosphate, albumin, vitamin D, an d alkaline phosphatase ( PTH) will screen for metabolic bone disease. \200 Rheumatoid f actor (RF) and anti-citrullinated protein antibody (ACPA) tests such as anti-cyclic citrull inated peptide (CCP) may be useful for diagnosing rheumatoid arthritis. Antinuclear antibod y (ANA) and a screen of extractable nuclear antibodies (ENAs) may be helpful for the evalua tion of a number of disorders, including systemic lupus erythematosus (SLE), Sjogren \200 \231s, and scleroderma. In children with JIA, a positive ANA is associated with an increased risk of uveitis. Other investigations to consider: serum angiotensin converting enzyme (sACE) for sarcoidosi s, glycosylated hemoglobin in diabetics, serum and urinary protein electrophoresis for myel oma. Other diagnostic procedures \200 Nerve conduction studies are useful to evaluate upper li mb neuropathies. Joint/bursa \202 uid aspiration is mandatory in suspected cases of sepsis and should be s ent for culture and microscopy. Crystal arthropathy should also be considered. Treatment of wrist and hand disorders Treatment for speci \201 c diseases is considered in Part 2. Management of the soft tissue lesions in the hand and wrist, like elsewhere, combi nes periods of rest and splinting with active physical therapy, avoidance of repetitive act ivity, and analgesia. In most cases, the condition will resolve CHAPTER 2 Regional musculoskeletal conditions 56 spontaneously, but severe or persistent pain and disability may warrant input from a hand o ccupational therapist, local steroid injections, or occa- sionally surgical soft tissue dec ompression. \200 Conditions that respond to local steroid therapy include: tenosynovitis, e.g., De Quervain \200\231s \200 tendon nodules and ganglia \200 \202 exor tenosynovitis (and trigger \201 nger) \200 Dupuytren \200\231s contracture \200 carpal tunnel syndrome \200 synovitis: radiocarpal and radioulnar at the wrist, MCPs and PIPs, \201 rst carpometacarpal (CMC). The accuracy of needle placement is likely to be improved by US guidance; however, greater ef \201 cacy from such an approach over blind injection has not yet been shown. See Corticosteroid Injection Therapy and Principles of Rehabilitation at the end of this chapter. Functional evaluation (from a physical and occupational therapist) is likely to be of use i n cases of polyarthropathy. Early use of splints, orthotics, and exercises may lead to grea ter functional ability and a decrease in symptoms. Surgical options for the hand and wrist may include: fusion or resection of the carpal bones \200 ulna styloidectomy and wrist synovectomy (RA ) \200 tendon repair and transfer operations (RA) \200 synovectomy of joints and/or ten dons (RA) \200 fusion of small joints \200 PIP/MCP replacements \200 Dupuytren \200 \231s release/fasciectomy \200 carpal tunnel release \200 trapeziectomy for thumb CMC j oint OA Many of these procedures primarily reduce pain; function may not be restored. This page intentionally left blank CHAPTER 2 Regional musculoskeletal conditions 58 Upper limb peripheral nerve lesions Background \200 Upper limb peripheral nerve lesions a re common. Most are entrapment neuropathies. Occasionally, nerve trauma may present to primary care providers o r rheumatologists with (primarily) regional muscle weakness. Although not speci \201 c for its diagnosis, the triad of pain, paresthesias, and weakness is suggestive of nerve entrapment. Features may be considered more speci \201 c for nerve entrapment if there is a history of acute or overuse trauma proximal to the distribution o f the symptoms. Lesions may characteristically occur in association with speci \201 c activities, occupations, or sports (e.g., ulnar neuropathy in cyclists). \200 Accurate di agnosis relies on demonstration of the anatomic lesion. Useful in this respect is knowledge of likely sites of entrapment or damage and, in the case of entrapment, the ability to eli cit a positive Tinel sign (i.e., percussion over the site of entrapment eliciting sensory s ymptoms in the appropriate nerve distribution). Always compare examination \201 ndings in both upper limbs. \200 Nerve conduction studi es are an adjunct to clinical diagnosis. They should not be relied on to make a diagnosis i n the absence of good clinical data. MR techniques and their interpretation are becoming increasingly more sophisticated in iden tifying patterns of abnormality in these disorders. The long thoracic nerve \200 Entrapment is in the differential diagnosis of painless shou lder weakness. The nerve origin is at C5 \200\223C7, and its course runs beneath the subscapular is and into the serratus anterior. Muscle paralysis is often painless and implies loss of the last 30 of overhead arm extens ion, disrupted scapular rhythm, and scapula winging. Winging is demonstrated by inspection from behind with the patient pressing against a wall with an outstretched arm. Damage to the nerve occurs typically from an anterior direct blow or brachial plexus injury . Damage sometimes occurs after carrying heavy backpacks (e.g., army recruits) or after sur gical resection of a cervical rib. It can also occur spontaneously after infection. There is no speci \201 c treatment. The suprascapular nerve \200 The nerve origin is at roots C4 \200\223C6; its course is la teral and deep to the trapezius, through the suprascapular notch, terminating in the supras pinatus and posteriorly in the infraspinatus. It carries pain \201 bers from the glenohum eral joint and AC joint. Impingement of the nerve at the suprascapular notch should be considered in a patient complaining of shoulder pain despite a normal examination and imagi ng tests. Injury to the nerve often gives diffuse shoulder pain, although painless paralysis of the muscles can occur. UPPER LIMB PERIPHERAL NERVE LESIONS 59 Injury is often thought to occur from repeated stretching of the nerve at the notch. Weight lifters are prone to bilateral injury and volleyball players prone to dominant side injury. Compression by ganglia or tumors occurs and can be con \201 rmed by MR. Ulnar nerve The ulnar nerve originates from C8 and T1. It lies along the medial side of the brachial artery in the upper arm, then above the medial humeral epicondyle where it passes posteriorly, piercing the medial intermuscular septum. It then runs behind the elbow in a groove between the olecranon and medial epicondyle, covered by a \201 brous sheath and ar cuate ligament (cubital tunnel). Following the line of the ulna in the \202 exor compartm ent of the forearm, branches supply the \202 exor digitorum profundus (FDP) and the \202 exor carpi ulnaris (FCU). The nerve enters the hand on the ulnar side dividing into su per \201 cial (palmaris brevis and skin over the medial one and a half digits) and deep (s mall muscles of the hand) branches. \200 Lesions are usually due to entrapment. \200 Th e ulnar nerve is occasionally damaged in the relatively exposed cubital tunnel (cubital tun nel syndrome) resulting in pain and paresthesias along the medial forearm, wrist, and fourt h/ \201 fth digits. Damage may occur from direct trauma, compression, or recurrent subluxa tion. The Tinel test at the elbow may be positive and there might be sensory loss over the palmar aspect of the \201 fth digit.