Investigations Joint space narrowing and osteophyte formation is found on radiographs. Loos e bodies may also be seen. See Figure 5.18. Nerve entrapment around the elbow The median, ulnar, and radial nerves may be trapped aroun d the elbow, each giving rise to distinct clinical presentations. Nerve conduction studies are helpful in the investigation of nerve entrapment syndromes. Radial tunnel syndrome The deep branch of the radial nerve (posterior interosseus nerve or PIN) may become compressed as it passes through a tunnel formed by \201 brous tissue next to the super \201 cial head of the supinator muscle. As this is adjacent to the joint cap sule, compression of PIN may occur as a result of synovitis of the capsule. Presentation is usually with lateral elbow pain that radiates into the dorsal aspect of the forearm. Examination \200 Examination reveals local tenderness where the radial nerve crosses the head of the radius. Tinel \200\231s sign may be positive at this point. Provocation of the entrapment occurs w ith resisted supination of the elbow with the elbow in extension. If severe, a PIN palsy re sults, with clinical \201 ndings consistent with a more peripheral radial nerve palsy: \200 \200 Figure 5.18 Sclerosis, osteophytes and joint space narrowing is evident on this plain radio graph of an osteoarthritic elbow. An effusion can also be detected. Weak wrist extension due to paralysis of extensor carpi radialis brevis and extensor carpi ulnaris. Weak thumb abduction (abductor pollicis longus). Loss of thumb extension (extensor pollicis brevis and longus). Loss of finger extension (extensor indicis proprius, extensor digitorum communis and extensor digiti minimi). The diagnosis of a PIN palsy can be dif \201 cult if the palsy is partial and the differential diagnosis includes extensor tendon r upture at the wrist. In both cases, those muscles and tendons closest to the ulnar are affe cted \201 rst. The \200\230tenodesis test \200\231 can help differentiate between the tw o. The extensor tendons are intact if the wrist is passively \202 exed and the \201 nge rs extend due to tension in the extensor tendons. If they do not extend it is likely that t he tendons are ruptured. Treatment In the majority of cases, conservative measures with anal- gesia and self-managem ent are indicated. Physiotherapy and advice about avoidance of heavy physical work are impo rtant. \200 \200 If there is a history of locking, arthroscopic removal of loose bodies provides good sympto matic relief. If osteoarthritis primarily affects the lateral aspect of the joint, excision of the radial head results in pain relief. Rarely, replacement arthroplasty is indicated. Osteochonditis dissecans After the knee, the elbow is the most common site of osteochondrit is dissecans. Necrosis of part of the articular cartilage occurs, with associated necrosis of the underlying bone. Eventually, this separates from healthy bone resulting in a loose f ragment within the joint. This fragment is usually part of the capitulum of the humerus. Th e cause of osteo- chonditis dissecans is unclear. Treatment of PIN compression is conservative, but decompression of the PIN can be undertake n surgically in those with refractory symptoms or signi \201 cant motor \201 ndings. History There is a history of mild mechanical pain and, following separation of the fragmen t, there is a history of locking of the joint. The pronator teres syndrome (median nerve entrapment) Around the elbow, the median nerve ca n become entrapped as it passes through the two heads of the pronator teres muscle. Present ation is with anterior elbow pain and distal paraesthesia identical to that seen in carpal tunnel syndrome. Treatment consists of conservative measures, including physiotherapy, and NSAIDs, and sur- gery, is reserved for those who are not responding. Surgery involves relea se of the humeral head of pronator teres. Examination An effusion can be detected in the early stages and there may be some mild rest riction of movement. Treatment Treatment is conservative until the fragment results in locking, an indication fo r surgery. CHAPTER 5 Regional musculoskeletal anatomy and conditions 151 Examination The pain is exacerbated by resisted pronation of the forearm. Weakness of the \202 exors of the index and middle \201 ngers may result in resting \201 nger extensio n, the so-called \200\230papal sign \200\231. Examination There may be tenderness over the ulnar nerve as it lies within the groove behin d the medial epicondyle, and there is usually a positive Tinel \200\231s test. There is was ting of the intrinsic muscles of the hand in advanced cases Cubital tunnel syndrome The ulnar nerve runs in the groove behind the medial epi- condyle o n its path into the forearm. The main complaint is of pain on the medial side of the elbow with paraesthesia along the ulnar border of the forearm extending into the little and ring \201 ngers. There may be a history of weak grip. Treatment is with activity modi \201 ca tion, NSAIDs if severe, and splinting. Surgical techniques involve ulnar nerve trans- posit ion or less commonly, medial epicondylectomy. Further reading Bosworth DM. The role of the orbicular ligament in tennis elbow. J Bone Jt Surg Am 1955; 37: 527 \200\22333. Kraushaar BS, Nirschl RP. Tendinosis of the elbow (tennis elbow). Clinical features and \201 ndings of histological, immunohistological and electron micrsopic studies. J Bone Jt S urg Am 1999; 81: 259 \200\22378. Putnam MD, Cohen M. Painful conditions around the elbow. Orthopaed Clin N Am 1999; 30: 109 \200\22318. THE HAND AND WRIST 152 The hand and wrist The hand is the body \200\231s key functional asset, and for full function and positioning, a normal shoulder and elbow joint is necessary. radius, and acts as a pulley for the extensor pollicis longus tendon. The scapholunate inte rval lies just distal to and in line with Lister \200\231s tubercle or dorsal tubercle of t he distal radius. Movements of the wrist include palmar \202 exion, dorsi \202 exion, ul nar deviation, radial deviation, and circumduction. The intercarpal joints contribute to pa lmar \202 exion. Regional anatomy The anatomy of the wrist, the carpal tunnel, and the hand will be discusse d. The osteology of the hand and wrist are visualized in Figure 5.19. The carpal tunnel The carpal bones form an upside down arch (as viewed with the wrist in su pination) with the \202 exor retinaculum (= transverse carpal ligament) spanning the arch from the palmar surfaces of scaphoid and trapezium radially to the pisiform, triquetrum, a nd hamate ulnarly. The combination of arch and spanning \200\230roof \200\231 of the \202 exor retinaculum produces a tunnel, the carpal tunnel. Bones The wrist When the wrist is in a neutral position, the wrist and hand are in the same plane as the longitudinal axis of the radius and middle metacarpal. The term \200\230wris t joint \200\231 normally implies the radiocarpal joint, rather than the other articula- ti ons of the carpal bones. The hand The thumb metacarpal articulates with trapezium. The thumb \200\230carpometacarpa l \200\231 joint (CMCJ) and the metacar- pals of the \201 ngers articulate proximally wit h the trapezoid, capitate, and hamate. The thumb has only two phalanges \200\223 proximal and distal \200\223 and, therefore, only one interphalan- geal joint. The \201 ngers hav e a proximal, middle, and distal phalanx and, therefore, both a proximal and distal inter- phalangeal joint. The \201 rst CMCJ lies between trapezium and the base of the \201 rst metacarpal bone. It is a multiplane and very mobile joint allowing thumb extension, abduct ion, adduction, and opposition with the \201 ngers. Flexion/extension at the \201 rst C MCJ is up to 50 of movement and abduction/ adduction is up to 70 . The fourth and \201 fth CMCJs of the The radiocarpal joint is formed by the articulation of the distal radius with the scaphoid and lunate. The trique- trum articulates with the triangular \201 brocartilage (TFCC), wh ich is a layer of \201 brocartilage of variable thickness at- tached to the ulnar end of the distal radius and the fovea at the base of the ulnar styloid. The distal end of the uln ar, therefore, does not articulate directly with the proximal carpal row. More distally, fu rther movement occurs at the intercarpal and intermetacarpal articulations. The distal radius and ulnar also articulate with each other at the distal radioulnar joint. The terms \200\230radial \200\231 and \200\230ulnar \200\231 are preferred to medial and lateral, due to the effect of supination at the elbow on posture of the hand. \200\230Lis ter \200\231s tubercle \200\231 is a bony prominence on the dorsum of the thumb MCP trapezoid capitate hamate thumb CMC triquetral trapezium pisiform scaphoid radius ulnar lunate Figure 5.19 Osteology of the hand and wrist. CHAPTER 5 Regional musculoskeletal anatomy and conditions 153 \201 ngers are more mobile than the second and third, allow- ing greater opposition with the thumb, and enable the hand to be cupped. The metacarpophalangeal joints (MCPJ) are modi \201 ed hinge joints. The main function of the MCPJs is to provide \202 exion/extension of the \201 ngers, with palmar \202 exion up to 70 , but they also enable the span of the hand to be varied though abduction and adduction. The interphalangeal joints, both pro ximal (PIPJ) and distal (DIPJ) in the second to \201 fth digits, and the interphalangeal joint of the thumb are hinge joints. Palmar \202 exion is up to 120 , and there is not n ormally signi \201 cant extension in these joints. palmar ligament tendon of flexor carpi ulnaris radial collateral ligament ulnar collateral ligament tendon of flexor carpi radialis Joint capsules The wrist joint capsule is bound down to the distal radius and ulnar, bones of the carpus, and bases of the metacar- pals, such that, in combination with the intrinsic ligaments between carpal bones, the distal radioulnar joint is a sepa- rate cavity from th e radiocarpal joint which is also separate from the midcarpal joint. In a normal wrist, the refore, radiographic contrast material injected into any one of these three separate caviti es should remain within the cavity into which it is injected. The distal radioulnar joint w ill develop a communication with the radiocarpal joint if the TFCC becomes perforated eithe r as a result of a trau- matic tear, as a result of degenerative breakdown or in \202 amma tory synovitis. The radiocarpal joint will commu- nicate with the radiocarpal joint if eith er the scapholunate or lunatotriquetral ligaments become perforated. The capsule of the met acarpophalangeal joints is strengthened by the radial and ulnar collateral ligaments on the sides and by the palmar plate on the palmar surface. The capsule attaches to the articular margins. deep transverse metacarpal ligaments Figure 5.20 Capsule and ligaments of wrist, carpal, and metacarpophalangeal joints. Ligaments The ligaments of the hand and wrist are seen in Figure 5.20. \200 Ligaments of the wrist: these are classi \201 ed as palmar, dorsal, intrinsic, or extrinsic. Each ligam ent is named according to the bones to which it attaches, with the most proximal or radial bone attachment being given \201 rst, e.g. scapholunate and lunatotriquetral. The palmar capsular ligaments are more numerous than the dorsal and tend to converge distally. Distal radioulnar ligaments: the dorsal radioulnar and palmar radioulnar ligaments are major stabi lizers of the distal radial ulnar joint. They form the dorsal and palmar margins of the TFC C, and the most proximal \201 bres con- verge on the ulnar side and attach into the fovea , at the base of the ulnar styloid process. The most distal \201 bres of the palmar radio ulnar ligament form ligaments between the disc of the TFCC and the lunate, and between the disc and the triquetrum. Palmar radiocarpal ligaments: the palmar radiocarpal ligaments are strong condensations within the palmar wrist capsule and pass from the distal radius to th e scaphoid, lunate, and capitate, and form a double V-shaped (one V proximal to the other, rather than side by side) structure with the distal apex on the capitate and the proximal a pex on the lunate. Dorsal capsular ligaments: these are most easily pictured as a Z-shaped structure made up of the dorsal radioulnar ligament, the dorsal radiocarpal ligament and th e dorsal intercarpal ligament. The main attachments from the proximal end of the Z to dista l end of the Z are: distal ulnar, distal radius, triquetrum, and scaphoid and trapezoid (th e Z is reversed on the left wrist when looking from the dorsal aspect). Ligaments in the digits: a similar distribution of ligaments occurs in the interphalangeal joints, with collaterals to give longitudinal stability and a palmar plate, which limits ex tension. The articular surface of the metacarpal head, when viewed laterally, is not spheri cal, but ovoid, with the top of the oval level with the dorsal cortex of the metacarpal and the bottom of the oval projecting palmar to the palmar cortex of the metacarpal. The colla teral ligaments are attached to the side of the metacarpal head closer to the top of the ov al and, therefore, are slack when the MCPJ is in extension, but taut when the MCPJ is in \202 exion. Abduction at these joints, therefore, can only occur when there is slack in the collateral ligaments, i.e. when these joints are in extension; abduction is not possible w hen these joints are fully \202 exed. Unlike the MCPJ collateral ligaments, the collat- e ralligaments of the interphalangeal joints remain taut throughout movement, providing a gre ater degree of stability and restricting lateral movement. See Figure 5.21. Muscles and tendons The main muscles of the hand and wrist and their actions are tabulated in Table 5.7. Extensor tendons. The extensor tendons are bound down to the dorsum of the wr ist by the extensor retinaculum. This is a condensation of the fascia of the extensor compa rtment that forms a strap-like structure. The strap is attached to the distal radius at one end and the distal ulna at the other, and additionally has separate attachments in between such that there are six separate dorsal compartments through which the exten- sor tendons run. THE HAND AND WRIST 154 Table 5.7 Main muscles of the wrist and hand Prime dorsi \202 exors at the wrist Flexor carpi radialis Flexor carpi ulnaris proximal interphalangeal joint distal interphalangeal joint Palmaris longus Extensor pollicis brevis Dorsi \202 exors at the MCPJs Extensor indicis proprius metacarpo-phalangeal joint ( \200\230cam \200\231) Extensor digitorum communis Extensor digiti minimi Flexor pollicis brevis Lumbricals Interossei Flexor digiti minimi br evis Flexor digitorum super \201 cialis Flexor digitorum profundus Interossei lumbricals Palmar \202 exors at the MCPJs Flexion of the PIPJs Flexion of the DIPJs Dorsi \202 exors of the DIPJs and PIPJs Flexion of the thumb IPJ Dorsi \202 exion of the thumb IPJ Flexor pollicis longus Extensor pollicus longus Figure 5.21 Metacarpophalangeal ( \200\230cam joint \200\231) and interphalangeal joints in \202 exion and extension. The \201 rst compartment lies over the radial styloid, on the lateral aspect of the dista l radius, and contains the ten- dons of abductor pollicis longus (APLS) and extensor pollic is brevis (EPB). Within the second compartment are the two tendons of the radial wrist exte nsors [extensor carpi radialis longus (ECRL) and extensor carpi radialis brevis (ECRB)]. In the third compartment is the extensor pollicis longus tendon, which is prone to rupture in association with fractures of the distal radius. The fourth compartment contains the exten sor indicis proprius (EIP) tendon and the four tendons of extensor digitorum communis (EDC) . Along the \202 oor of this com- partment runs the terminal branch of the posterior inte rosseous nerve (PIN). The \201 fth compartment lies over the ulnar head and contains the extensor digiti minimi (EDM) tendon. This tendon tends to be the \201 rst extensor tendon to rupture if the ulnar head erodes through the dorsal distal radi- oulnar joint capsule. This may occur in either rheumatoid or osteoarthritis. The sixth compartment lies over the ulnar aspect of the ulnar head, just dorsal to the ulnar styloid, and contains the tendon o f extensor carpi ulnaris (ECU). The extensor tendons leave their compartments beneath the e xtensor retinaculum and diverge to their respective digits where they are held in place by tethers. The main tethers are the saggital bands, which hold the tendons centrally over the dorsal aspect of the MCPJs. The saggital bands are attached to each side of the ten- don a nd run around each side of the base of the proxi- mal phalanx in a palmar direction and att ach to each side of the palmar \202 exor tendon sheath. In addition, the extensor tendons are held by an attachment to the underlying MCPJ capsule. The extensor tendon then separat es into three parts, called slips, at the level of the middle of the proximal phalanx. The slips comprise a central slip and two lateral slips. The central slip of the extensor tendo n inserts into the base of the middle phalanx and extends the PIPJ. The two lateral slips d iverge to join the lateral bands of the intrinsic muscles at the level of the distal third of the proximal phalanx, where they form the conjoined lateral band. The conjoined lateral bands m erge at the distal third of the middle phalanx and form a terminal tendon, which inserts in to the base of the distal phalanx and extends the DIPJ. The intricate weave of the tendons of the long extensors and the aponeurotic expansion of the tendons of the intrinsic muscles form an aponeurosis known as the dor- sal aponeurosis (synonymous with dorsal apparatus). The action of the central slip is extension of the PIPJ and the action of the terminal tend on is extension of the DIPJ. The action of the dorsal aponeurosis at the MCPJ, however, is \202 exion. This is because the tendons of the intrinsic muscles (interossei and lumbrica ls) arise palmar and proximal to the center of rotation of the MCPJ, and then run dorsally to insert into the extensor tendon distal to the MCPJ. The intrinsic muscles of the hand ar e therefore \202 exors of the MCPJs and, via the extrinsic extensor tendon with which the y merge, extensors of the PIPJs and DIPJs. Tightness of the intrinsic muscles, as may occur in condi- tions, such as rheumatoid arthritis, results in PIPJ \202 exion being more res tricted when the MCPJs are in extension than in \202 exion (if the intrinsic muscles are \200\230tight \200\231 the MCPJs are pulled into \202 exion and the PIPJs into exten- si on). If the MCPJs are then moved passively into \202 exion, this has the effect of reduci ng the tension in the intrinsic tendons and so \202 exion at the PIPJ may be easier. Flexor tendons. The \202 exor tendons of the digits and the median nerve run through the carpal tunnel. Neither the \202 exor carpi radialis (FCR) tendon and adjacent radial ar- tery, nor the flexor carpi ulnaris (FCU) tendon and adjacent ulnar nerve run through the ca rpal tunnel. The super \201 cial \202 exors of the hand are visualized in Figure 5.22. \200 The \202 exor tendons then leave the carpal tunnel, diverge and attach to the digit s in the hand. The palmaris longus tendon, when present (it is absent in 15% of the populat ion) inserts into the \202 exor retinacu- lum, and the palmar aponeurosis. The palmar apo neuro- sis is a fan-like expansion of fascia in the palm. There are CHAPTER 5 Regional musculoskeletal anatomy and conditions 155 tendons of flexor digitorum profundus and flexor digitorum superficialis flexor sheaths lumbricals superficial palmar arch common digital branches flexor digiti minimi flexor pollicis brevis hypo- thenar muscles thenar muscles abductor digiti minimi abductor pollicis brevis opponens digiti minimi opponens pollicis flexor retinaculum ulnar artery radial artery Figure 5.22 Super \201 cial aspect of palm. longitudinal condensations (bands) running to each digit. In addition, there are transverse \201 bres and also vertical \201 bres attaching to the overlying skin. The palmar apon eu- rosis is, therefore, part of a three dimensional fascial structure known as the palmar fascial complex . The \202 exor tendons and median nerve lie on the radial side of the p almaris longus tendon. The flexor tendons, after leaving the carpal tunnel, diverge to thei r respective digits and are guided along the palmar side of the phalanges by a tunnel. This tunnel comprises the tendon sheath and a series of pulleys that keep the tendon centrally placed. The pulleys occur at intervals and are a series of annular and cruciform retain- er s that prevent \200\230bowstringing \200\231 of the tendons (i.e. they hold the tendons ag ainst the phalanges). The \200\230A1 \200\231 ( \201 rst annular) pulley lies at the leve l of the MCPJs and is the pulley most commonly involved in \200\230trigger digits \200\231 . thenar muscles, but sometimes actually runs through the ligament. The sensory distribution of the median nerve is normally from the palmar aspect of the thumb as far as and including the radial border of the ring \201 nger. This nerve also provides sensibility to the dor sum of the digits distal to the distal interphalangeal joints (sensory supply to the skin o f the dorsum of the hand proximal to these points is provided by the radial nerve). In addi tion, via the recurrent motor branch, the median nerve sup- plies the muscles of the thenar eminence and the most radial two lumbricals. There is some variation in innerva- tion of t he thenar muscles such that the \202 exor pollicis brevis and opponens pollicis are somet imes innervated by the ulnar nerve. The abductor pollicis brevis muscle is, therefore, the muscle of the thenar eminence most consistently innervated by the median nerve, and, there- fore, the muscle to test when assessing the median nerve at the level of the wrist. The an atomy of the carpal tun- nel is seen in Figure 5.23. Ulnar nerve: the ulnar nerve approache s the wrist beneath and to the radial side of the FCU tendon. As the FCU tendon inserts int o the pisiform, the nerve runs around the radial side of the pisiform and passes into the p alm via Guyon \200\231s canal. The ulnar nerve innervates all the small muscles of the hand (apart from those inner- vated by the median nerve, as previously described) and provides sensibility to the little \201 nger and ulnar border Nerves of the hand \200 Median nerve: from the antecubital fossa, where it lies to the ulnar side of the radial art ery, the median nerve runs deep to the \202 exor digitorum super \201 cialis (FDS) muscl e into the wrist. At the wrist the nerve runs through the carpal tunnel alongside the \202 exor tendons of the digits. The recurrent motor branch, to the thenar eminence, usuall y loops back over the distal end of the \202 exor retinaculum to enter the proximal end o f the THE HAND AND WRIST 156 median nerve palmar aponeurosis flexor retinaculum flexor carpi radialis ulnar artery and nerve flexor pollicis longus thenar muscles hypothenar muscles radial artery flexor tendons in carpal tunnel branches of radial nerve extensor tendons bones of carpus Figure 5.23 Carpal tunnel and contents (tendon shealths not shown); transverse section. of the ring \201 nger, on both the palmar and dorsal aspects of the lengths of these \201 ngers. As with innervation of the muscles, there can be some variation in sensory supp ly in that the ulnar nerve may encroach on median nerve territory by innervating as far as the skin of the ulnar border of the middle \201 nger. Polley HF, Hunder GG. The wrist and carpal joints, metacar- pophalangeal, proximal, and dis tal interphalangeal joints. In: Polley HF, Hunder GG (Eds) Physical Examination of the Join ts, 2nd edn. Philadelphia: WB Saunders, 1978: 90 \200\223148. Schneider LH. Flexor tendons \200\223 late reconstruction. In: Green et al. (Eds) Green \200\231s Operative Hand Surgery, 4th edn. Edinburgh: Churchill Livingstone; 1999: 1909. Smith RJ. Intrinsic muscles of the \201 ngers: function, dysfunction and surgical reconst ruction. Instruct Course Lect 1975; 24: 200 \200\22320. Williams PL, Warwick R, Dyson M, Ba nister LH. Joints of the upper limb. In: Williams PL et al. (Eds) Gray \200\231s Anatomy, 3 7th edn. Edinburgh: Churchill Livingstone 1989: 499 \200\223516. Further reading Markison RE, Kilgore ES, Hand. In David JH (Eds) Clinical Surgery. St Louis: CV Mosby; 1987; 1087: 2292 \200\223353. McMurty RY. The hand. In: Little AH (Ed.) The Rheumatological Physical Examination. Orlando : Grune and Stratton; 1986: 91 \200\223100. McMurty RY, Little AH. The wrist. In: Little AH (Ed.) The Rheumatological Physical Examination. Orlando: Grune and Stratton, 1986: 83 \200 \2239. This page intentionally left blank HAND AND WRIST: REGIONAL MUSCULOSKELETAL CONDITIONS 158 Hand and wrist: regional musculoskeletal conditions the triangular \201 brocartilage complex (TFCC). The radius and ulna articulate at the si gmoid notch. The DRUJ and TFCC can be disrupted via trauma, such as a radial fracture malun ion, or degenerative and in \202 ammatory conditions. \200 Main causes of hand and wrist pain Articular \200 \200 \200 In \202 ammatory arthritis. Osteoarthritis. Crystal arthritis. Patients may have degeneration or tears of the cartilagi- nous disc. If the radius loses he ight, such as in a radial fracture, too much force goes through the relatively longer ulna. Patients will often tell you they have pain and clicking on the ulna side of the wrist. Tw o simple tests can be done that indicate ulna-sided pathology include pain on ulna deviatio n of the wrist with pain on ballotment of the ulna. Analgesia and temporary splinting can h elp alleviate pain, but referral to a hand surgeon is usually recommended. Surgery is compl ex and often involves long periods of post-operative immobilization. Periarticular \200 \200 \200 \200 \200 Tenosynovitis, e.g. De Quervain \200\231s, trigger \201 nger. Ganglia. Tophi/RA nodules. Dupytrens contracture. Diabetic cheirarthropathy. Bone \200 \200 Fracture. Osteochondritis, e.g. scaphoid fracture. Neurological \200 Table 5.8 Differential diagnosis hand and wrist pain by location Peripheral nerve entrapment, e.g. carpal tunnel syndrome, PIN entrapment. Brachial plexus p athology. Thoracic outlet syndrome. Cervical radiculopathy. \200 \200 Radial Osteoarthritis thumb carpometacarpal joint Scapho-trapezial-trapezoid osteoarthritis Scaphoid fracture, or consequent scaphoid collapse De Quervain \200\231s disease Conditions associated with osteoarthritis of the hand See Chapter 12 p. 571(OA). The locati on of pain can be vital in making a diagnosis. See Table 5.8. Ganglion Ulna Distal radioulnar joint osteoarthritis and instability Triangular \201 brocartilage complex injury or degeneration. Hamate hook fracture and non-union Mucous cyst This is a sub dermal cyst at the dorsum of the DIPJ. It arises from the joint c apsule. Patients must be aware that is a sign of a degenerative joint and not a disease in itself. They can be excised, but carry the risk of recurrence. Extensor carpi ulnaris (ECU) tendinitis Piso-triquetral osteoarthritis Dorsal Avascular necrosis of the lunate (Keinbock \200\231s disease) Ganglion Carpometacarpal joint osteoarthritis (CMCJ OA) This condition exists in up to 70% of people over the age of 60. There is a ratio of 10:1 women to men. \200 Scapho-lunate dissociation Scapho-lunate advanced collapse On clinical examination there is a prominence at the base of the thumb with pain on axially loading, and extending or \202 exing the thumb. Early treatment includes hand therapy wi th splinting, analgesia, and glucocorticoid injection. Surgery involves removal of the trap ezium with various procedures to stabilize the base of the thumb. Patients must be told tha t they will be mobilized for approxi- mately 6 weeks after surgery and that it may take up to 6 months to regain their preoperative hand function. Tenosynovitis This is de \201 ned as in \202 ammation of the synovial lining of a tendon sheath. Table 5.9 Causes of tenosynovitis Proliferative Erosive, e.g. RA Deposition, e.g. amyloid Crystalline, e.g. gout, pseudo-gout Scaphoid non-union and advanced collapse (SNAC) This is a secondary arthritis of the carpus because of a previous scaphoid fracture that has not united. Septic, e.g. bacterial, mycobacterial Finger, e.g. trigger Tendon entrapment and stenosing tendonvaginitis Radial side of wrist, e.g. De Quervains \200\231 disease Scapho-lunate advanced collapse (SLAC) Damage to the scapho-lunate ligament leads to rotary subluxation of the scaphoid. As a result of this secondary arthritic changes begin in a lo calized manner at the radio- scaphoid joint and progress to pan-carpal arthritis. Tendons, e.g. ECU, EPL, FCR History There is usually a history of pain and swelling along the line of the affected tend on, usually an extensor tendon, with subsequent loss of function. A careful history will de ter- mine an underlying in \202 ammatory or infectious cause. Distal radio-ulna joint disease The radius and ulna articulate at the distal radio-ulnar jo int (DRUJ). The base of the ulna is attached to the radius via CHAPTER 5 Regional musculoskeletal anatomy and conditions 159 Young babies can have a \200\230congenital \200\231 trigger thumb. Parents may notice that the thumb does not extend. On examination a nodule may be felt at the base of the thumb an d it may not be possible to extend the thumb. This is due to a similar pathology and warran ts referral to a hand surgeon. Examination \200 Soft tissue swelling, which moves as the affected tendon is moved. There may be crepitus on movement of the affected ten- don through the tendon sheath. There may be features of an a ssociated carpal tunnel syndrome. Tendon rupture or triggering may be present. De Quervain \200\231s tenosynovitis De Quervain \200\231s tenosynovitis occurs in the \201 rst extensor compartment on the back of the thumb. This includes the extensor pollicus brevis (EPB) tendon and abductor pollicus longus (APLS) tendon. \200 Investigations The most speci \201 c imaging technique is ultrasound, which allows visuali zation of the synovitis around the tendon and guides accurate placement of an injection int o the tendon sheath. Ultrasound will also detect heterogeneity of a ten- don indicating deg enerative change. See Figure 5.24. Pain is the main presenting symptom with triggering a rare \201 nding. Flexion of the thu mb and ulna deviation of the wrist (Finkelstein \200\231s test) causes pain, but is not pat hognomonic of de Quervain s tenosynovitis. It is common in breast feeding and new mothers d ue to over-use and positioning of the hands. Treatment modalities include glucocorticoid in jection and ultimately surgical decompression if this does not work. Intersection syndrome Intersection syndrome is a tenosynovitis of the second dorsal compart ment of the wrist (This is where the APLS and EPB tendons cross the common radial wrist ext ensors). \200 Patients present with pain and swelling 4 cm proximal to the radial side of the wrist. It i s more common with repetitive wrist motion especially in sports, such as rowing and weight lifting. In the majority of cases rest, splinting, and glucocorticoid injection is suf \201 cient. Occasionally, surgical decompres- sion is necessary. Figure 5.24 There is thickening around the tendon and synovitis around the extensor group 1 tendons, but with no \202 uid visualized on ultrasound. Management of tenosynovitis \200 Extensor carpi ulnaris (ECU) tenosynovitis This is reactive tenosynovitis in the ECU tendon and it is often initiated by a twisting injury of the wrist. \200 In those with an infectious cause, debridement and antibiotic therapy is necessary, with no role for conservative management or glucocorticoid injection (see Chapter 16 p. 459) Hand therapy, rest, and splinting are of bene \201 t. Medical management aims to prevent tendon rupture. Targeted glucocorticoid injections for non-infectious tenosynovitis. Surgical ste ps include synovectomy and trigger \201 nger release with carpal tunnel decompression. Do rsal synovectomy involves a long incision on the back of the hand, followed by bandage or p laster immobilization for 2 weeks. After this period, removal of sutures and hand therapy c an begin. Scar massage and occasionally desensitization may be needed. It is associated with nocturnal ulna-sided wrist pain and swelling. Pain in the sensory bra nch of the ulna nerve is common. Pain in all motions of the wrist is noted although it is w orse in an extensor and ulna deviated position. The diagnosis is con \201 rmed when pain i s obliterated by injecting local anesthetic into the ECU sheath. Management is the same as intersection syndrome. \200 \200 Kienb cks disease This encompasses avascular necrosis of the lunate bone. It involves a de gree of wrist degeneration. Reasonable func- tion, however, is maintained. The cause of thi s condition is uncertain, but is not thought to be related to trauma. Speci \201 c examples of tenosynovitis Trigger \201 nger Trigger \201 nger and thumb a re common, and can be primary or associated with diabetes, gout, renal disease, and other r heumatic diseases. The flexor tendon is unable to smoothly slide up and down its sheath, an d as a result the \201 nger locks/clicks into a \202 exed position. It can be very pain ful to straighten it up. \200 History \200 \200 \200 \200 Pain particularly on the dorsum of the wrist. Stiffness with subsequent loss of motion. Wea kness of the wrist with diminished grip strength. There is rarely a history of trauma. Examination \200 \200 On clinical examination the triggering can be elicited and a nodule is often palpated at th e distal palmar crease. Treatment includes glucocorticoid injection with an approximately 5 0% success rate. If the glucocorticoid injection does not work then surgical release of the trigger \201 nger is performed, usually under local anesthetic. Tenderness to palpation with occasional dorsal swelling. Decreased range of wrist motion. Investigations \200 Radiographs show characteristic increased density of the lunate bone, as well as fragmentat ion with collapse of the lunate. See Figure 5.25. MR may be useful and can help in planning treatment. HAND AND WRIST: REGIONAL MUSCULOSKELETAL CONDITIONS 160 diabetes, connective tissue diseases, pregnancy, and previ- ous wrist fracture. It occurs m ost commonly in women in the 30 \200\22360-year age groups. The differential diagnosis for this condition includes a cervical radiculopathy, as well as spinal cord lesions and periph eral neuropathies, such as alcoholic and diabetic neuropathies. History \200 Patients often present with a typical history of numbness in the median nerve distribution, particularly in the morning, with pins and needles in a similar distribution. They often r eport that shaking the hand in the morning makes it better. Patients initially have pins an d needles, and pain in the above mentioned distribution and as time progresses they may wel l go on to having diminished sensation. Patients often present with odd pain shooting up th e arms. Figure 5.25 On this plain radiograph of a patient with Keinbock \200\231s disease, sclerosi s of the lunate bone can be seen on both views. The disease is staged according to the degree of degen- eration, with subsequent secondary changes to the car- pal structure and scaphoid bone. Examination \200 Examination should include the cervical spine, as well as a neurological examination of the hand. There may be diminished sensation in the median nerve distribution with wasting of t he thenar muscles. Gentle tapping over the median nerve at the wrist in a neutral position often produces paraesthesia in the dis- tribution of the median nerve. (Tinel \200\231s tes t) Holding the wrist in a \202 exed position will often bring on similar symptoms of ting ling (Phalens \200\231 test). The disease can be divided into mild (sensory de \201 cit on ly), moderate (sensory and motor de \201 cit), and severe (sensory de \201 cit with motor absence) The diagnosis of this disease is generally clinical. However, nerve condition stu dies may be used as an adjunct. Management \200 A short period of physiotherapy with casting or bracing can be attempted, but it is not rec ommended unless there is quick resolution of symptoms. Arthroscopic evaluation may help wit h diagnosis and can provide pain relief. Surgery can be complex and may involve prolonged p eriods of immobilization after osteotomy. Advanced disease can be treated with proximal row carpectomy or arthrodesis. Recovery can often take up to 6 months. Preisser \200\231s disease \200 This is a similar condition to Kienb ck \200\231s, but affects the scaphoid bone. It prese nts with radial and dorsal sided wrist pain. There may be an association with previous non- speci \201 c wrist trauma but this disease is differentiated from scaphoid fracture and no n-union. Management is also complex and beyond the scope of this text. Management \200 \200 Conservative management, such as a Futuro splint and non-steroidal anti-in \202 ammatory d rugs often help. Injection of local anesthetic and glucocorticoid into the carpal tunnel ha ve been shown to keep patients symptom-free for at least 1 year in over 50% of cases. Injec tion is best provided by a hand surgeon or rheuma- tologist as the median nerve is at risk during the injection. If conservative treatment has not worked then early referral to a han d surgeon would be recommended. The treatment would include surgical decompression of the c arpal tunnel, which can usually be performed under local anesthetic. Upper limb nerve entrapment syndromes The radial, ulna, and median nerves may all be compre ssed predominantly from the elbow to the wrist. Patients present with a wide range of sympt oms starting with occasional paraesthesia, and may progress to sensory loss, muscle weaknes s, and pain. Severity depends on the degree of compression, as well as duration of compress ion. It is imperative that the whole limb, as well as the cervical spine is examined when e valuating these patients. Double crush syndrome, as described by Upton and Acoma, is the co mpression of a nerve at one level, which will make it susceptible to damage at another leve l. For example, cervical nerve route compression predisposes a patient to carpal tunnel dis ease. Median nerve compression in the forearm \200 The proximal median nerve can be trapped between the ligaments and muscles at the elbow, an d proximal fore- arm, e.g. between the bellies of the pronator teres muscle. The anterior i nterosseous nerve can be trapped in the forearm resulting in diminished thumb \202 exion and weakness in pronation at 90 of \202 exion. History \200 \200 