706 \200 Early complications \200 VTE 4% \200 Dislocation 3% \200 Deep infection 2% \200 Fra cture 1% \200 Nerve palsy 1% \200 Limb-length a m u a r t d n a discrepancy 1% \200 Death 0.4 \200\2230.7%164 s c i d e a p o h t r O Fig 1. AP image shoulder hemi- arthroplasty. Courtesy of Norfolk and Norwich University Hos pital (NNUH) Radiology Department. 707 Infected hip and knee prostheses This may be a disastrous complication of joint replacement \200\224presenting with pain, loss of function, fever, or wound in \202 ammation. Periope rative wound complications, obesity, increased age, diabetes mellitus, steroid use and rheu - matoid arthritis increase risk. Staphyloccal skin commensals are the most common infectiv e organisms Investigations: CRP/ESR, blood culture and aspi- ration of joint. Plain radiogr aphs may show peri-prosthetic loosening. CT/MRI may be of limited use due to artifact. Gall ium/labeled leukocyte imaging may be useful in hard to diagnose cases Treatment: Early on, debridement + anti- biotics may be enough. Later, with loosening of components, radical deb ride- ment must include removal of all prosthetic material, as well as any involved bone an d soft tissue. Sometimes reconstruction by exchange arthroplasty works, eg for less virulen t infections. Antibiotics may be needed for months. Patient selection is vital, eg those wi thout draining sinuses, without immuno- compromise, and with adequate bone quality after de bridement.172 The Mayo Clinic reports a 13% failure rate with a 2-stage reconstruction. a m u a r t d n a s c i d e a p o h t r O Another alternative may be the removal of all foreign material and allowing ankylosis to occur, ie a Girdlestone pseudarthrosis, for the hip. SBE \200\223style antibio tic prophylaxis antibiotic-impregnated cement? \200 Dentistry-associated prosthesis in fection with oral bacteria is very rare and risks of antibiotics are palpable (>500 penicil lin-caused deaths/yr, in the USA), and SBE-style prophylaxis is not recommended. Colonoscopy + polypectomy may be more risky than dentistry; some rec- ommend prophylaxis, if <6 months since replacement. The best prophylaxis might be achieved with a combination of gentamicin-im- pregnated cemen t, systemic antibiotics for >24h, and surgery performed in ultra- clean environments (lamin ar air \202 ow theaters/surgeons in space suits , although the additional cost of this m ay be prohibitive or prove to be ineff ective). Reim- plantation need not require use of ce ment: hydroxyapatite coated total prosthe- ses are an alternative.173 See \201 g 2 for th e usual constituents found in bone cement. Other systemic long-term complications of joint replacements174 Fine frag- mentation may lead to metal poisoning (eg cobalt) targeting mito chondria: suspect if visual/hearing loss and 24h urine cobalt excretion >1.5 g/L. Fig 2. AP radiograph of a cemented total hip arthroplasty. Bone cement usually contains: me thylmethacrylate (forms the polymer); a starter, initiator + inhibitor chemicals; an antibi otic (eg gentamicin clindamycin); a coloring agent (eg chlorophyll, hence green color); and a radiopaci \201 er (eg ZrO2 or BaSO4).1 1 The \201 rst hip replacement was done by Philip Wiles at the Middlesex Hospital in 1938. The Charnley low friction arthroplasty was \201 rst used in the 1960s. 2 For DVT/PE prophylaxis, NICE recommends using either LMWH, fondaparinux, dabigatran or rivaroxaban for 10 \200\22335 days post-op depending on the typ e of surgery, and agent chosen. Fig 3. AP radiograph of the left hip after Bir- mingham hip resurfacing.2 Images courtesy of Norfolk and Norwich Uni- versity Hospital (NNUH) Radiology Department. Joint injection and aspiration Joint aspirations Diagnostic role: Any blood, crystals, or p us?175 Therapeutic role: For tense eff usions, septic eff usions, and haemarthroses. Approa ches for speci \201 c joints are given below and on p710. \200\207Remember that aspiratio n of a joint with a prosthesis should only be done under the strictest sterile condi- tions (ie in the operating theater) to minimize risk of introducing infection. Steroid injection s to in \202 amed joints, bursae, or tendon sheaths aim to \200\201in \202 ammation and relieve pain, perhaps by \200\201prostaglandin synthesis, stabiliz- ing mast cells, or \200\201tissue calci \201 cation, or increasing vascularization and per- meability of syno vium. Side effects: Skin atrophy (hydrocortisone acetate is safer than triamcinolone), haem arthrosis, facial \202 ushing, urticaria, Charcot \200\231s arthropathy, post-injection \202 are syndrome (synovitis with fever), paresis, and septic arthritis ( \211 1 in 14,000 injections). \200\207It is essential that steroids are not used in septic conditions and, if any doubt at all exists, results of syno- vial \202 uid culture should be awaited. Re member the possibility of tuberculous synovitis \200\224especially in immigrant populations . Repeated injections are more dangerous: beware ligamentous laxity, joint instability, cal ci \201 cation, or tendon rupture. 708 a m u a r t d n a s c i d e a p o h t r O Preparations are available: hydrocortisone acetate (cheapest, shortest act- ing), methylpre dnisolone, and triamcinolone. They may be mixed with 1% li- docaine. When triamcinolone is used for injecting near short tendons, 10mg strength is preferred to 40mg as tendon rupture has been reported after the latter. Despite our best intentions \200\230joint \200\231 in jections often fail to meet their tar- get (50% in one study in which contrast material was also injected); those off -target are less likely to relieve symptoms.176 Conditions respo nding reasonably well to steroid injection Localized sub- deltoid bursitis; supraspinatus, infraspinatus, and subscapular tendinopathy; shoulder arthritis; tennis and golfer \200\231 s elbow, arthritis of elbow, radioulnar, acromioclavicular, and sternoclavicular joints; ga nglia; trigger \201 ngers; de Quervain \200\231s disease; strains of collateral and cruci ate ligaments of knee; supra- patellar, infrapatellar, and Achilles tendinopathy; plantar f asciitis; traumatic arthritis of metatarsophalangeal joints; and sesamo- \201 rst-metatars al joint. Preparation Check you have swabs, needles, and sterile bottles. For aspiration of viscid \202 uid (eg haemarthrosis) use a 19G needle. For the larger joints use a 21G nee dle, and for \201 ngers and toes a 23G needle. Locate joint margins care- fully before cl eaning with chlorhexidine in 5% spirit or surgical spirit; once the skin is clean use scrup ulous aseptic no-touch technique. Remember that anti- septics and local anesthetics take 3m in to work; even then, the skin is clean but not sterile. Samples for microbiology should b e sent in sterile containers, those for cytology or crystal examination in heparinized or F BC containers. Knee joint The patient lies with knee supported slightly \202 exed and mus cles re- laxed. Palpate the joint space behind patella either medially or laterally \200 \224the lateral approach may be less reliable.177 Insert a needle horizontally between the patella and femur. Slight resistance is felt on traversing the synovial mem- brane; it shou ld be possible to aspirate \202 uid, and injection \202 uid should \202 ow easily. Us ual doses: 25 \200\22350mg hydrocortisone acetate, 40mg methylpredniso- lone, 20mg triamcin olone. Repeat injections should be longer than 3 months apart. If injection is used for pre patellar bursitis, give 25mg hydrocortisone acetate into the most tender spot. The ankle Pl antar \202 ex foot slightly, palpate joint margin between tibialis an- terior (the most m edial) and extensor hallucis longus (lateral to tibialis ante- rior) tendons just above tip of medial malleolus. Inject 25mg hydrocortisone acetate into the joint. 709 Synovial \202 uid in health and disease Blood, crystals or pus? Aspiration of synovial \202 uid is used diagnose haemar- throses, or infectious or crystal (gout and pseudogout) a rthropathies. Appearance Viscosity WBC/mm3 Neutrophils Clear, colorless Clear, straw High Bloody, xan- th ochromic Turbid, yellow a m u a r t d n a s c i d e a p o h t r O <200 <25% Normal High Non-in \202 ammatory, eg OA Haemorrhagic, eg tumor hemophilia, trauma Acute in \202 ammat ory1 \200 Acute gout \200 Rheumatic fever \200 Rheumatoid arthritis Septic \200 TB \200 Gonorrhoeal \200 Septic (non-gonococcal)2 <5000 <10,000 <25% <50% Variable Decreased 14,000 18,000 16,000 80% 50% 65% Turbid, yellow Decreased 24,000 14,000 16,000 70% 60% 95% For in \202 ammatory causes of arthritis: Synovial \202 uid WBC >2000/mm3 is 84% sensiti ve (84% speci \201 c); synovial \202 uid neutrophil count >75% is 75% sensitive (92% spe ci \201 c). \200\207NB: not all labs are equally skillful.178 Pathological fractures De \201 nition A fracture that occurs in diseased or abnormal bone. Disrup- tion of bony structural integrity means that even trivial forces can produce a fra cture, so suspect a pathological fracture if the energy of the trauma is abnormally low for the resulting injury. Common sites include the subtrochan- teric femur and the proximal hu meral shaft. Causes The commonest causes are osteoporosis (so-called \200\230fragility \200\231 frac- tures) and bony metastases (eg from breast or prostate primaries). Rarer cau ses include osteomalacia, osteitis (bone infection), primary bone tumor and osteogenesis im perfecta. Management If the underlying di- agnosis is unclear, then do rigorous directed in vestigation, eg in a search for a primary cancer. Without treat- ing the bone metastases, t he chances Courtesy of Norfolk and Norwich University Hospital (NNUH) Radiology Department. of healing are nearly zero. Chemo- and radiotherapy with \201 xation (eg intramedullary nail insertion bone cement) may allow slow healing. Prevention Prevention of fracture fr om metastatic deposits may include external beam irradiation and prophylactic intramedullar y nail insertion.179 Osteoporosis prevention is also a major issue, covered by NICE. \200 1 80 \200\207Remember pathological fractures, as prevention is important and treatment may b e diff erent. Fig 1. Diff use bony sclerotic lesions, put- ting the patient at risk from pathological fra cture. \200 \200 : Metastasis from prostate and breast, and rarely GI carcinoma; primary lympho- ma; multiple myeloma. \200\207Remember to image the whole femur if a proximal path ological fracture is iden- ti \201 ed \200\224the forces through any \201 xation device could snap any other surrounding in \201 ltrated bone. 1 Includes eg Reiter \200\231s syndrome, pseudogout, SLE etc. 2 Includes Staphs, Streps, Ly me, and Pseudomonas (eg post-op). Joint injections II Shoulder injection As shoulder pain from soft tissue causes is common ( life- time incidence 10%), and pain can be chronic ( \200\20523% resolve within 4wks), thi s is one of the most commonly injected joints. But we do not know who to inject or when in their illness, as trials are few, and the best ones cast doubt on the bene \201 t of any i njection.21 Anterior approach: (aspiration, synovitis, frozen shoul- der) seat the patient with arm relaxed by side of chest. Feel the space between head of humerus and glenoid cap 1cm below coracoid process. Insert 21G green needle into the joint space (enters joint spac e when almost up to hilt) and in- ject 25 \200\22350mg hydrocortisone acetate. \200\207Do not go medial to the coracoid process (neurovascular structures, p765 \201 g 2). Lateral approach: (subacromial bursitis, painful arc syndrome) inject 25 \200\22350mg hydrocortison e acetate with lidocaine just below the lateral tip of the acromion, pointing downwards and advancing medi- ally. If the needle is withdrawn from touching the head of humerus with sl ight pressure on the plunger, a drop in pressure is felt as the bursa is entered. Painful a rc pain may be reproduced. A 2nd injection may be given after >48h. Tennis elbow (see also p666) 25mg hydrocortisone acetate with 1mL lidocaine is injected with force to area of maxi mal tenderness over lateral humeral con- dyle moving to and fro down to bone several times. A second injection may be needed, eg after 2 weeks. Warn the patient that symptoms may wor sen brie \202 y after the injection has been given, and that long-term (>6 weeks) relief o f symp- toms may not be provided \200\224better results may be obtained with physiotherapy and elbow manipulation.181,182 Avoid triamcinolone and Depo-Medrone \200\224be- cause inj ections are super \201 cial, fat necrosis may occur. Elbow joint injection With elbow \202 exed at 90 , inject 25mg hydrocortisone ac- etate between proximal head of radius (lo cate by rotating patient \200\231s forearm and feeling the radial head rotate) and lateral epicondyle by lateral approach (needle 90 to skin), or posteriorly between olecranon and lateral epicondyle. \200\207Avoid the posteromedial aspect, as the ulnar nerve lies behind the epicondyle. Biceps tendinopathy is worsened by externally rotating the arm. Insert nee dle parallel to tendon (if resistance, it is in the tendon: withdraw a bit); inject 25mg hy drocortisone acetate into tendon sheath and 25mg into joint. Ultrasound guid- ance for this injection increases accuracy.183 Wrist injection Inject 25mg hydrocortisone acetate 1 \200 \2231.5cm deep between ex- tensor tendons of ring and little \201 ngers between ulnar hea d and lunate. De Quervain \200\231s tenosynovitis Extensor pollicis brevis and abductor pol licis lon- gus tendons \200\224on traversing the extensor retinaculum on the dorsal wrist \200\224may cause a tender swelling (p668). With needle almost parallel to skin pointing pr oximally, inject 25mg hydrocortisone acetate slowly just distal or proximal to the radial s tyloid, at the site of maximum tenderness. If needle in tendon, injec- tion is diffi cult s o withdraw until easy \202 ow occurs. Carpal tunnel Introduce the needle just proximal to the distal wrist crease, to the ulnar side of palmaris longus (locate before starting by r esisting active \202 exion of the wrist), angled at 45 in a distal to proximal directio n. \200\207Do not use local anesthetic. If the patient jumps or reports an \200\230electr ic shock \200\231 then you are probably in, or touching, the nerve. Redirect the needle tow ards the ulnar side and then inject 25mg hydrocortisone acetate. The intention is to delive r steroid around the \202 exor tendons and not into the carpal tunnel itself. If the \201 rst injec- tion fails, consider repeating with 10 \200\22320mg triamcinolone. A splint worn for the next few days may mitigate symptoms which can occur at the time of injection. Trigger \201 nger Insert needle at MCP skin crease parallel to \202 exor tendon, point - ing to palm. Palpate tendon thickening in palm; proceed as for de Quervain \200\231s. Fir st carpometacarpal joint of thumb Avoiding radial artery, inject 25mg hy- drocortisone acet ate at base of \201 rst metacarpal at 1cm depth in anatomical snuff box (aim at base of l ittle \201 nger). \200\207In all areas, learn from an expert. 710 a m u a r t d n a s c i d e a p o h t r O 711 a m u a r t d n a s c i d e a p o h t r O Fig. 1. (a) Dorsal aspect of the right ankle indicating anatomical landmarks \200\224shown here is the anterior ankle approach. (b) Dorsal aspect of the right wrist indicating anatomical landmarks \200\224shown here fro m left to right are the injection sites for the wrist joint, de Quervain \200\231s tenosyno vitis & the 1st carpometacarpal joint. (c) Diagrammatic representation of the anterior aspect of the right shoulder region. The bl ue areas indicate synovial membranes of the subacromial bursa and the glenohumer- al joints \200\224shown here are the anterior shoulder approach (below) and the acromiocla- vicular joint approach (above). (d) The right elbow, \202 exed \200\224shown from left to right the posterior and lateral approaches.184 Tendon rupture and injury The main tendons to rupture are the extensor tendons of the \201 ngers, the Achilles tendon ( \201 g 2), the long head of biceps (p664), supraspinatus (p664), and the quadriceps expansion ( \201 g 1). The cause may be sharp or blunt trauma (anything from sporting injuries to rubber bullets). Ultrasound aids diagnosis, but its use fulness is largely operator-dependent. Mallet \201 nger Often caused by a sudden blow to an extended \201 nger \200\224e.g. hit by basketball on outstretched \201 nger \200\224 which leads to rupture of the extensor tendon at the distal phalanx. Treatment: Splint the aff ected digit for 6 weeks (in slight hyper-extension) using a Stack splint or a molded al uminum splint. If untreated the mallet \201 nger may develop into a swan-neck deformity. If con- servative treatment fails, or the mallet \201 nger is associated with a large avu lsion fracture (>30%) refer to a hand surgeon for consideration of surgical \201 xation.1 85 Boutonni re deformity Rupture of the central slip of the extensor tendon (at the base o f the middle phalanx) allows the lateral bands of the extensor mechanism to slip towards th e palm, turning them into \202 exors of the PIP joint. The result is \202 exion at the PIP and hyperextension of the DIP joint. It can occur following injury (forced \202 exion of extended PIP joint or volar dislocation of dis- tal \201 nger at PIP joint) or second ary to rheumatoid arthritis. Acute injuries are typically treated by splinting PIP in compl ete and constant extension, allowing movement at DIP and MCP joints. Referral to hand thera py is recommended. Achilles (calcaneal) tendon rupture Typi \201 ed by sudden pain at the back of the ankle during running or jumping as the tendon ruptures. Pain may be perceived a s a \200\230kick \200\231 rather than actual pain. It is possible to walk (with a limp), a nd some plantar \202 exion of the foot remains, but it is impossible to raise the heel fr om the \202 oor when standing on the aff ected leg. A gap may be palpated in the tendon c ourse (particularly within 24h of injury). The squeeze test (Simmonds \200\231 test) is sen sitive: ask the patient to kneel on a chair, while you squeeze both calves \200\224if the A chilles is ruptured, there is less plantar \202 exion on the aff ected side. Treat- ment: Tendon repair (percutaneous or open) is often preferred by young, athletic patients. Late- presenting ruptures usually need reconstructing.186 Surgery has a lower re-rupture rate, bu t risks potentially devastating infection. Conservative treatment may be most suitable for smokers, diabetics and those >50yrs old. Conservative management usually requires initial c asting in equinus position. Typically there is no weight bearing for 6 \200\2238 weeks. Qua driceps expansion rupture Injury may be direct (eg blow) or indirect (stumbling causing sud den contraction of the apparatus). The quadriceps ex- pansion ( \201 g 1) encloses the pat ella and inserts into the tibial tuberosity as the patellar tendon. Non-traumatic causes: P seudogout; Wilson \200\231s disease; renal failure with hyperparathyroidism.187 Treatment: Rupture can occur at the site of quadriceps insertion to the patella, through the patella b y fracture, or by avulsion of the patellar tendon from the tibial tuberosity. In all with e xtensor mechanism disruption (no straight leg raising) surgery is mandatory. After re- pair , the knee is immobilized for >4 weeks; then intensive physiotherapy helps regain knee func tion. Many have persistent weakness.188 Tenosynovitis Tendons and surrounding synovium may become locally in- \202 amed (?from strain) so causing pain, eg supraspinatus tendinopath y and bi- cipital tendinopathy (p664), or de Quervain \200\231s (p668). Acute frictional sy novitis at the wrist is another example, with swelling over wrist and thumb extensors. If p alpation doesn \200\231t detect crepitus, at some sites, stethoscope auscultation reveals s ounds like bronchial breathing.1 Treatment: In wrist tenosynovitis, a splint for 3 weeks (l eaving the \201 ngers free) may be needed to allow in \202 amma- tion to subside. 712 a m u a r t d n a s c i d e a p o h t r O 1 \200\230Breathing \200\231 on the painful right arch on great toe \202 exion with \200\230vesicular \200\231-type breathing on the unaf- fected left side.189 713 a m u a r t d n a s c i d e a p o h t r O Fig 2. The medial aspect of the ankle, show- ing the extensor and \202 exor tendons of th e foot. The Achilles tendon tends to rupture 5cm proximal to its insertion into the cal- c aneus. Also note the ordering of the \202 exor tendons posterior to the medial malleolus, from anterior to posterior \200\224this can be re- membered with the mnemonic Tom, Dick an d, Harry: \200 Tibialis posterior \200 Flexor digitorum longus \200 Posterior tibial artery \200 Posterior tibial nerve \200 Flexor hallucis longus. Fig 1. The extensor expansion of the knee. Nerve compression syndromes1 \200 Carpal tunnel syndrome (CTS) \200\207This is the commo nest cause of hand pain 714 at night. It is due to compression of the median nerve as it passes under the \202 exor r etinaculum. \200 : \200 >1 : 1. Signs are in the median nerve distribution: \200 Tingl ing or pain is felt in the thumb, index, and middle \201 ngers. \200 When the pain is a t its worse, the patient characteristically \202 icks or shakes the wrist to bring about relief. Pain is especially common at night and after repetitive actions. Aff ected persons may experience clumsiness. \200 Wasted thenar eminence & \200\201sensation over the late ral 3 digits (not 5th). \200 Lateral palmar sensation is spared as its supply (the palm ar cutaneous branch of the median nerve) does not pass through the tunnel. Phalen \200\231s test: holding the wrist hyper \202 exed for 1min reproduces the symp- tom s. (This is more reliable than Tinel \200\231s test \200\224tapping over the tunnel to pro- duce paraesthesiae. Note: Phalen \200\231s \202 exing, Tinel \200\231s tapping.) a m u a r t d n a Tests: Nerve conduction studies are unnecessary if history and examination are conclusive. US may be useful, MRI is less diagnostically accurate; neither are routine.190,191 Posterio r interosseous nerve (PIN) compression The branch is compressed on passing through the prox imal supinator muscle, eg after forearm fracture or excessive exercise. Patients experience weakness of thumb and \201 nger exten- sion. Electromyographic studies are typically pos itive Radial tunnel syndrome involves compression of the same nerve, but presents with late ral forearm pain rather than weakness. Electrodiagnostic studies tend to be negative Examin ation may show weakness of long \201 nger extensors, and short and long thumb exten- sors , but no sensory loss. Treatment Rest, splints, NSAIDs. are \201 rst line. Steroids in- j ections may help. In resistant cases surgical decompression of areas of potential compressi on of the PIN (eg the arcade of Fr hse, ie the free edge of supinator).192 Anterior intero sseous nerve compression This median nerve branch may be compressed under the \201 brous origin of \202 exor digitorum profundus, causing weakness of pinch and pain along the for earm \200\231s radial border. Examination shows weakness of the long thumb \202 exor and \202 exor profundus to the index \201 nger \200\224the patient will be unable to \202 ex the DIP joint of the index \201 nger and PIP joint of the thumb to make a rounded \200\230O \200\231 shape Treatment Initial conserva- tive managment with surgical decompres sion if required. Ulnar nerve compression at the wrist Uncommon. Compression occurs at Guyo n \200\231s Canal. Loss may be motor or sensory. Compression can be due to a mass or extern al compression (in cyclists). Diagnose clinically, US may help. Meralgia paraesthetica is a symptom complex of numbness, paraesthesiae, and pain (eg burning/shooting) in the anterola teral thigh, caused by lateral femoral cutaneous nerve entrapment, eg under the lateral par t of the inguinal ligament (or neuroma, or other mononeuropathy). Causes: Tight jeans; body armor; seatbelts; patient-positioning devices (eg for hip surgery); \200\200intra- abdomi nal pressure (eg pregnancy, obesity, ascites), \200\226diabetes mellitus, \200\226tumors, 193 repetitive contraction of inguinal muscles during sports train- ing,194 herniorrhaphy, pregnancy, pelvic osteotomy (eg for grafts).195 \201\231 \201\231: Lum- bar disc hernia. \201\227: (often self-limiting but may recur196). Lose weight if needed, rest, NSAID car bamazepine197 cortisone and local anesthetic injection at the anterior superior iliac sp ine gives unpredictable results. Common peroneal compression Nerve compression against the head of \201 b- ula (eg plaster casts, thin patients lying unconscious, proximal \201 b ula fracture, squatting, obstructed labor)198 causes inability to dorsi \202 ex the foot. Sensa- tion may be \200\201 over the dorsum of the foot. Treatment: Most recover spontane- ously but surgical decompression may be needed (eg if >3 months without improvement). Phys iotherapy and splint until foot-drop recovers. s c i d e a p o h t r O 1 Ulnar nerve compression at elbow, p666; brachial plexus injury, p764; peripheral nerve in jury, p760 & p716. 715 Managing carpal tunnel syndrome Treat any treatable association (see MINIBOX) Rest, weight reduction and wrist splints are \201 rst line treat- ment.199 20% of cases will spontaneo usly resolve.For carpal injection, see p710. (Symptom relief beyond 1 month compared to pla cebo is unproven.)200 More permanent results are obtained from decom- pression by \202 ex or retinaculum division.201 Although a certain proportion ( 7%) have worse symptoms post su rgery. Full implications of endoscopic techniques are uncertain.202 CTS associations \200 Myxoedema \200 Pregnancy; the Pill \200 Gout & pseudogout \200 Diabetes; obesity \200 Cardiac failure \200 Acromegaly \200 Rheumatoid a m u a r t d n a s c i d e a p o h t r O arthritis Premenstrual state \200 Amyloidosis Overuse phenomena at work Activity requiring repetitive actions, particularly those associa ted with pro- longed muscle contraction, may lead to chronic symptoms. Employers have a dut y to provide a safe working envi- ronment and well-designed chairs and tools, and frequent short breaks. Chang- es of posture and activity help to reduce work-related \200\230non-sp eci \201 c arm pain \200\231. If no diagnosis has been made, this term is preferred to the fallacious repeti- tive strain injury (RSI) \200\224see \201 g 1. The cost of these inju ries in suff ering, and hours lost from work, is considerable as treatment of established s ymptoms is often diffi cult and may necessitate change in employment \200\224if one is avai lable. Compensation is a vexed issue, and recent court judgments have gone in favor of empl oyers in some instances, and in favor of patients in others. Some people argue that the con dition does not exist as a separate medical entity, emphasizing lack of histopathology. It should be noted that this is not a prerequisite for a disease (see Sudden infant death, p14 8) \200\224and in any case histopathology is sometimes demonstrable. Treatments tried inclu de splint- ing (may prolong the problem), physiotherapy, \200 -blockers for relaxation, an d the Alexander technique for posture re-education. Synonyms \200 Non-speci \201 c arm pain = Work-related upper limb injury = Occupational overuse syndrome = Isometric contraction myopathy = RSI (although, see \201 g 1) Those who use vacuum cleaners, assemble cars, or play stringed instru- ments may all develop overuse phenomena, as can sports players (p705). Fig 1. Why is the term repetitive strain in- jury a fallacy? Just because chest pain from a ngina can be provoked by walking up hills, walking up hills does not cause coronary artery stenosis (although the idea for some may be enough to cause a little heart \202 utter). A nd so, because use of the arm may provoke the symptoms of an underlying condition (eg carpa l tunnel syndrome, osteoarthritis at the base of the thumb, de Quervain \200\231s disease), it does not mean that it is the cause of the un- derlying condition. Courtesy of Dr Tom Turmezei. Testing peripheral nerve motor functions Upper limb203 Nerve root Muscle Trapezius C3,4 Rho mboids C4,5 C5,6,7 Serratus anterior C5,6 716 Test by asking the patient to: Shrug shoulder (via accessory nerve).204 Brace shoulder back . Push arm forward against resistance. Adduct arm from above horizontal, and push it forwar d. Adduct arm below horizontal. Pectoralis major (clavicular head) C6,7,8 Pectoralis major (sternocostal head) Supraspinatus Infraspinatus C5,6 C5,6 C6,7,8 Latissimus dorsi Biceps C5,6 C5,6 Deltoid Radial nerve (C5 \200\2238) C6,7 ,8 Triceps C5,6 Abduct arm the \201 rst 15 . Externally rotate arm, elbow at side. Adduct arm from horiz ontal position. Flex supinated forearm. Abduct arm between 15 and 90 . a m u a r t d n a Extend elbow against resistance. Flex elbow with forearm half way between pronation and sup ination. Extend wrist radially with \201 ngers extended. Arm by side, resist hand pronati on. Keep \201 ngers extended at MCP joint. Extend wrist to ulnar side. Abduct thumb at 90 to palm. Extend thumb at MCP joint. Resist thumb \202 exion at IP joint. Brachioradialis s c i d e a p o h t r O C5,6 Extensor carpi radialis longus C6,7 C7,8 C7,8 C7,8 C7,8 C7,8 Median nerve (C6 \200\223T1) Pronator teres C6,7 C6,7 Flexor carpi radialis C7,8,T1 Flexor digitorum super \201 cialis Supinator Extensor digitorum Extensor carpi ulnaris Abductor pollicis longus Extensor polli cis brevis Extensor pollicis longus Keep arm pronated against resistance. Flex wrist towards radial side. Resist extension at P IP joint (while you \201 x his proximal phalanx). C8,T1 Flexor digitorum profundus I & II Flex the DIP of the index \201 nger, with the PIP held in extension. Resist thumb extension at interphalan- geal joint ( \201 x proximal phalanx). Abduct thumb (nail at 90 to palm). Thumb touches base of 5th \201 nger-tip ( nail parallel to palm). Extend PIP joint against resistance with MCP joint held in \202 e xion. C8,T1 Flexor pollicis longus C8,T1 Abductor pollicis brevis Opponens pollicis C8,T1 C8,T1 1st and 2nd lumbricals Ulnar nerve (C7 \200\223T1) C7,8,T1 Flexor carpi ulnaris C7,C8 Flex wrist towards ulnar side. Flex the DIP of the little \201 nger, with the PIP held in extension. Abduct \201 ngers (use index \201 nger). Adduct \201 ngers (use index \201 nger). Adduct thumb (nail at 90 to palm). Abduct little \201 nger. Flex the little \201 nger at MCP joint. Flexor digitorum profundus III & IV C8,T1 Dorsal interossei C8,T1 Palmar interossei C8,T1 Adductor pollicis C8,T1 Abductor digi ti minimi Flexor digiti minimi C8,T1 The musculocutaneous nerve (C5 \200\2236) C5,6 This may be injured at the brachial plexus, causing weakness of biceps, coracobrachialis, a nd brachialis. Forearm \202 exion is weak, some loss of sensation.1 Sources: MRC Handbook; www.rad.washington.edu/atlas; www.medmedia.com/05/324.htm See p762 f or dermatomes and peripheral nerve distributions. NB: root numbers in bold indicate that th at root is more important than its neighbor. \200\207Sources vary in ascribing particular nerve roots to muscles \200\224and there is some biological variation in individuals. The a bove is a reasonable compromise, and is based on the MRC guidelines. Lower limb205 Nerve root Muscle L4,5, S1 L5, S1,2 L2,3,4 717 Test by asking the patient to: Internal rotation at hip, hip abduction. Extension at hip (l ie prone). Adduct leg against resistance. Gluteus medius & minimus Gluteus maximus Adductors (obturator nerve) a m u a r t d n a s c i d e a p o h t r O Femoral nerve (L2 \200\2234, posterior division) L1,2,3 Iliopsoas Flex hip with knee \202 exed and lower leg supported: patient lies on back. Flex knee wit h hip external rotated. Extend knee against resistance. L2,3 L2,3,4 Obturator nerve (L2 \200\2234, anterior division) Hip adductors L2,3,4 Inferior gluteal nerve L5,S1,S2 Superior gluteal nerve L4,5,S1 Sciatic nerve (including the common peroneal nerveCP & tibial nerve) L4,5CP L5,S1CP L5,S1CP L5,S1CP L5,S1CP L5,S1,2T L4,5T S1,2 T L5,S1,2T S1,2T Sartorius Quadriceps femoris Adduct the leg. Gluteus maximus Hip extension. Gluteus medius & minimus Abduction and internal rotation of hip. Tibialis anterior Extensor digitorum longus Dorsi \202 ex toes against resistance. Extenso r hallucis longus Peroneus longus & brevis Extensor digitorum brevis Dorsi \202 ex 2nd \200\2234th toes (muscle of foot). Hamstrings Tibialis posterior Gastrocnemius Flexor digit orum longus Small muscles of foot Dorsi \202 ex ankle. Dorsi \202 ex hallux against resistance. Evert foot against resistance. Flex knee against resistance. Invert plantar \202 exed foot. Plantar \202 ex ankle joint. Flex terminal joints of toes. Make sole of foot into a cup. Quick screening test for muscle power Shoulder Abduction Hip Adduction Flexion Extension Fl exion Extension Flexion Extension Abduction Flexion Extension Flexion Extension Dorsi \202 exion Plantar \202 exion S1,2 L1,2 L5,S1 C5 C5, 7 C5, 6 Elbow Knee S1 L3,4 C7 C7,8 Wrist Ankle L4 C7 C7 \200\2238 Fingers C7 T 1 (ulnar) Quantifying strength The UK MRC scale objecti \201 es strength (reasonably well): Grade 0 No muscle contraction Grade 3 Active movement, with gravity eliminated Grade 1 Flicker of c ontraction Grade 4 Active movement against resistance Grade 2 Some active movement Grade 5 Normal power Grades 4 \200\223, 4, and 4+ describe movement against slight, moderate, and s trong re- sistance. Dynamometers help quantify strength.206 n=30 Remember to test proximal muscle power: ask the patient to sit from lying, to pull you towards himself, and to rise f rom squatting. Gower \200\231s sign (observed in a child with muscular dystro- phy and prox imal muscle weakness) shows the patient standing from a squatting position by \200\230clim bing \200\231 sequentially up his own legs. \200\207Also, observe walking (easy to forget, even if the complaint is of walking diffi culty!). See p680 and OHCM p471 for gait disorde rs. Reducing pain in A&E \200\207All patients should be asked speci \201 cally if they requir e pain relief. Clinical assessment is expedited by relieving pain. There is some evidence t o show that nurse initiated analgesia in Emergency Departments reduces time to relief of pa in.207,208 No acute pain is uncontrollable. If systemic analgesia is required, select the a nalgesic most appropriate to the type of pain. In pleuritic or mus- culoskeletal pain, NSAI Ds are often more effi cacious than a narcotic. NB: there are NO contraindications to narco tic analgesia (other than well-de \201 ned allergy which is very rare). If in doubt, TREAT ! Adjuncts Splint and elevate fractures and dislocations; RICE (p705). Local anesthesia Loc al in \201 ltration of wounds with 1% lidocaine; digital nerve block in \201 nger injuri es; femoral nerve block for fractured shaft of femur. NB: use plain lidocaine (no added adr enaline) for \201 nger blocks. Non-opioid systemic analgesia Paracetamol 1g/4 \200\2236h; aspirin 600mg co- deine 15 \200\22360mg/6h. NSAIDs: see below. Ketamine is a dissociati ve agent which can be used in subanaesthetic doses to provide analgesia. It should be used under the authority of a consultant. NSAIDS Ibuprofen 400 \200\223800mg/8h PO. Diclofenac 7 5mg PR/IM STAT (max dose 150mg in 24h) is useful in management of renal colic. Indometacin 100mg PR stat can also be used in acute pain, eg from renal colic or gout. Ketorolac is an injectable NSAID. Dose if >16yrs old: 10mg IM/IV over >15sec, every 2 \200\2236h, up to 90 mg/day (60mg if old or <50kg). \200\207NSAIDs ought to be avoided if there is a his- tory of renal impairment, peptic ulceration or inducing acute asthma. Gas Entonox is a 50% mix ture of nitrous oxide in O2. It is self-administered using a demand valve system and can pr ovide a good level of analgesia for short procedures (eg \201 nger relocation) or when aw aiting other forms of an- algesia. Nitrous oxide is now increasingly available in variable concentrations upto 70% \200\224and is no more likely to result in adverse eff ects than En tonox .209 Opioid analgesia should be given IV as a bolus or infusion (IM is too slow and unpredictable). Morphine dose: 50 \200\223100 g/kg, eg 2.5 \200\2237.5mg IV slowly. Furthe r increments should be titrated to the patient \200\231s response, initially at 5min in- te rvals. Respiratory depression is unlikely with careful titration. \200\207There is no de \201 ned maximum dose; a typical total dose is 10 \200\22320mg. Antiemetics are not always required routinely, but may be helpful in alleviating symptoms of nau- sea and vomiting (av oid metoclopramide in children: risk of oculogyric crisis). Naloxone (0.1 \200\2230.2mg sta t IV, then 0.1mg every 2mins until responsive) can be used to reverse eff ects of overdose. Fentanyl (1 \200\2232 g/kg IBW, eg 50 \200\223100 g IV) is useful for short procedures r equiring conscious sedation (cardioversion, re- duction of dislocated shoulder). Meptazinol is an opioid option, and can be given as 200mg every 3 \200\2236h PO \200\224eff ects are only partially reversed by naloxone. Tramadol is a synthetic opioid analgesic that has weak agonist activity at mu opiate receptors and inhibits serotonin and noradrenaline reuptake in the spi- nal cord; dose: 50 \200\223100mg/6h PO. Sedation Sometimes IV sedation is requi red for the sake of comfort and co- operation \200\224eg joint relocation, fracture reducti on (p734) or cardioversion (OHCM, p784). It is important that, if possible, one person is i n charge of drug administration and monitoring (HR, BP, O2 sats, GCS) and one person is in charge of the procedure. NB: this is not always possible, eg in remote locations, where sin gle physician procedural sedation will be required.210 Midazolam is an ef- fective sedative and should be titrated to response, starting with 2.5mg IV by slow injection (1mg in elder ly) and given in further 0.5 \200\2231mg increments. It is unusual for more than 5mg to be required. It can be given with mor- phine, though remember that morphine also has sedative eff ects. The use of propofol and/or ketamine is useful in experienced hands. \200\207Moni tor the patient throughout and after the procedure until GCS normal. 718 \200 a m u a r t d n a s c i d e a p o h t r O 719 Children with trauma needing pain relief Hospitals can be frightening. Toys, friendliness, a quiet room and a simple ex- planation of what is going to happen go a long way to avoid c reating distress. \200 Introduce yourself to the child (and their parents), get down to t heir eye level, and reassure them (and their parents). a m u a r t d n a s c i d e a p o h t r O Be positive and relaxed, let them know they are brave, and that you are go- ing to make them feel better and want to \200\234 \201 x \200\235 what ails them.