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Hand Soft Tissue

Hand infection and septic arthritis

Cellulitis and inflammatory hand swelling, deep space infection, septic arthritis and bite wounds

45 questions 5 source pages 1 fact-check flags

Images appear with the first question taken from each source page — tap a question to open it.

45 questions
Q1How are brachial plexus injuries classified anatomically?▸
  • Preganglionic versus postganglionic
  • Supraclavicular: root / trunk
  • Infraclavicular: cord / terminal branch
Q2What history is important in a brachial plexus injury?▸
  • Premorbid status, occupation, past medical history
  • Mechanism of trauma
  • Associated injuries and area of sensory deficit
  • Chronicity and current functional status
Q3How do you differentiate a preganglionic from a postganglionic brachial plexus injury clinically?▸
  • Horner's syndrome
  • Scapular winging: medial - serratus anterior, lateral - rhomboids
  • Histamine test: red and wheal occur locally, but the flare needs a reflex from the cell body; no flare = postganglionic
  • Long tract signs
  • Trapezius weakness (CN XI is in close proximity to the root)
Q4What is the role of nerve conduction studies in brachial plexus injury?▸
  • Delay 4-6 weeks for Wallerian degeneration to occur
  • Normal sensory conduction indicates a preganglionic injury
Q5What imaging and electrodiagnostic tests are used in brachial plexus injury?▸
  • CXR: raised hemidiaphragm, transverse process fracture, clavicle fracture, scapulothoracic dissociation
  • EMG: decreased recruitment, increased amplitude and duration; denervation in segmental paraspinal muscles (posterior rami) = preganglionic
  • XR C-spine: transverse process fracture
  • CT myelogram 3-4 weeks after injury
  • MRI (after 6 weeks) for empty nerve root sign + meningocele
Q6Describe the Leffert classification of brachial plexus injuries.▸
  • Type 1 = open
  • Type 2 = closed: 2a supraclavicular, 2b infraclavicular (usually involves branches from the trunks)
  • Type 3 = radiation/iatrogenic
  • Type 4 = obstetric: 4a Erb's, 4b Klumpke, 4c mixed
Q7What are the indications and timing for surgery in brachial plexus injury?▸
  • Indications: no clinical or electrodiagnostic signs of recovery, open injury, vascular injury, deteriorating neurology
  • Timing: open or vascular injury - immediate; preganglionic - 3 weeks; postganglionic - 3-6 months
  • Aim: restore upper limb function and protective sensation
Q8What is the reconstructive priority in brachial plexus injury?▸
  • Elbow flexion > shoulder abduction/ER stabilization > shoulder adduction
  • > sensation below elbow > wrist extension and finger flexion > intrinsics
Q9What is the role of physiotherapy in brachial plexus injury?▸
  • Physiotherapy to maintain range of motion while waiting for nerve recovery or reconstruction
Q10What are the primary nerve surgery options for brachial plexus injury?▸
  • Nerve repair
  • Neurolysis
  • Nerve graft for postganglionic injuries
  • Neurotization for preganglionic injuries
Q11What is neurotization?▸
  • Transfer of a functional but dispensable nerve to the distal end of a denervated nerve
  • Aim: maximise the number of myelinated axons per target function
Q12What nerve transfers are used for elbow and shoulder reconstruction in brachial plexus injury?▸
  • Elbow: Oberlin (fascicle from the ulnar nerve to supply the biceps)
  • Shoulder: Somsak, CN XI, contralateral C7, 3/4 intercostal nerves, phrenic nerve
  • Phrenic nerve: lung function recovery in 2 years; C/I in paediatric patients (elevated hemidiaphragm)
Q13What secondary reconstructive options exist for brachial plexus injury?▸
  • Tendon transfer and arthrodesis
  • Elbow: Steindler flexoplasty (proximalise FPO), triceps to biceps, pectoralis major transfer
  • Shoulder: FF - LHB to acromion, anterior transfer of posterior deltoid; abduction - latissimus dorsi + teres major to GT (Lepiscopo), arthrodesis
Q14What are the poor prognostic features in brachial plexus injury?▸
  • Delayed presentation, preganglionic injury
  • Old age, high-energy injury
  • Anaesthetic limb, flaccid limb
Q15Describe Doi's functional free muscle transplantation (FFMT) for brachial plexus injury.▸
  • 2-stage reconstruction using gracilis
  • Stage 1: 1st gracilis to restore elbow flexion and wrist extension (spinal accessory nerve neurotization)
  • Stage 2: 2nd gracilis to restore finger flexion (intercostal nerves neurotization)
Q16What risk factors suggest obstetric brachial plexus palsy?▸
  • High birth weight
  • Forceps delivery
  • Breech presentation
  • Shoulder dystocia
Q17What examinations and investigations are used in obstetric brachial plexus palsy?▸
  • Examine to locate the injury; Moro or ATR reflex can be done
  • XR, MRI
  • NCT, EMG
  • Toronto score (depends on ROM): <3.5 indicates surgery
Q18Describe the Narakas classification and prognosis.▸
  • I: C5-6 Erb - 90%
  • II: C5-7 Erb + wrist drop - 60%
  • III: C5-T1 total - 23%
  • IV: total + Horner - <10%
Q19What is the Mallet score used for?▸
  • To monitor progress in obstetric brachial plexus palsy
  • Assesses 5 major functions: abduction, ER, hand behind head, hand behind back, hand to mouth
Q20What is the initial management of obstetric brachial plexus palsy?▸
  • Maintain passive motion while the nerve recovers
  • Observe for 3 months initially
Q21What are the indications for primary surgery (before 6 months) in obstetric brachial plexus palsy?▸
  • C8-T1 with Horner
  • Total palsy with no biceps function by 3 months
  • Toronto score <3.5
  • EMG criteria by Smith; failure to progress after 1 year
  • Erb's with no biceps by 3 months; shoulder abduction by 2 months
Q22What primary nerve surgery is used for obstetric brachial plexus palsy?▸
  • Nerve graft / nerve transfer
  • Performed as primary surgery before 6 months
Q23What is the natural history of obstetric brachial plexus palsy?▸
  • >90% resolve
  • Prognosis follows the Narakas classification
  • Biceps absent at 3 months = poor prognosis
  • Borderline case: explore the brachial plexus earlier for a better outcome
  • Recovery usually up to 1 year
Q24How is a shoulder posterior dislocation in obstetric brachial plexus palsy managed?▸
  • Relocation + capsulorrhaphy
  • Derotational osteotomy if older
Q25What secondary procedures are used for shoulder internal rotation contracture?▸
  • <2 years = soft tissue procedure (subscapularis release)
  • >4 years (glenoid dysplasia) = bony procedure
  • Lepiscopo procedure: teres major + latissimus dorsi transfer to GT
  • Derotational osteotomy (Wickstrom procedure)
  • Elbow supination contracture: flexible = biceps rerouting, rigid = osteotomy
Q26How are felon and paronychia managed?▸
  • Felon: multiple septal compartments; midaxial incision and disrupt all septation
  • Paronychia: infection beneath the eponychial fold; needs elevation of the eponychium
Q27What is a collar button infection and how is it treated?▸
  • Webspace infection; clinically the finger is abducted
  • 2 cavities connected by a narrow isthmus
  • Dorsal spread through the deep transverse MC ligament causes digital artery thrombosis / numbness; proximal spread via lumbrical canal to midpalmar space
  • Rx: both dorsal (longitudinal) and volar (zig-zag) incisions with no connection (avoid neurovascular structures)
Q28What is the anatomy of the webspace (volar to dorsal)?▸
  • 1. Natatory ligament (superficial transverse metacarpal ligament)
  • 2. Neurovascular bundle
  • 3. Lumbrical
  • 4. Deep transverse metacarpal ligament
  • 5. Dorsal interossei; laterally bounded by the MCPJ capsule
Q29What are Kanavel's four cardinal signs of flexor tenosynovitis?▸
  • Finger held in a flexed position
  • Fusiform, sausage-like swelling
  • Tenderness along the flexor sheath
  • Pain with passive extension of the finger
  • Classically quoted: all four positive is >90% sensitive
Q30What are the systemic features and initial treatment of flexor tenosynovitis?▸
  • Systemic: only 17% have fever
  • Splinting, IV antibiotics and close observation for 24 hours
  • Operative treatment if failed
Q31How is flexor tenosynovitis drained and what is the Michon grading?▸
  • Close sheath irrigation (proximal to A1 and distal to A4) or open drainage (midaxial scar)
  • Open if Michon II or III; Brunner or midaxial incision
  • Michon: 1 = serous, 2 = pus, 3 = necrosis of tendon/pulley
Q32What are the routes of spread of flexor tenosynovitis?▸
  • Thumb --> radial bursa
  • Index, middle and ring --> midpalmar space
  • Little --> ulnar bursa
  • Radial/ulnar bursa --> horseshoe abscess / Parona's space (between PQ and FDP)
  • Thenar --> hypothenar (through radial bursa, Parona's space, ulnar bursa)
Q33Describe the radial and ulnar bursae and their drainage.▸
  • Ulnar bursa: MCPJ, widening 3rd and 4th MC (50% contiguous with FDP and FDS of little finger)
  • Radial bursa: MCPJ to proximal edge of TCL (95% contiguous with FPL sheath)
  • Rx: close irrigation 2-incision approach
  • Radial: incision adjacent to flexor crease of thumb MCPJ + ulnar to FCR
  • Ulnar: incision at A1 pulley and radial to FCU
Q34What are the boundaries and management of thenar and midpalmar space infections?▸
  • Thenar space (most common): thenar muscles (superficial), adductor pollicis (deep), 1st MC (radial), midpalmar septum (ulnar)
  • Rx thenar: volar incision along thenar crease (stay 1.5 cm from web) +/- dorsal between 1st and 2nd MC; risk to recurrent motor branch, superficial palmar arch, 1st/2nd digital NV
  • Midpalmar space: MF-LF flexors (superficial), interossei and 3-5 MC (deep), midpalmar septum (radial), hypothenar septum (ulnar)
  • Rx midpalmar: L-shaped incision (transverse distally then along radial border of hypothenar eminence)
Q35What are the spread patterns of a thenar space infection?▸
  • Can spread to the 1st web as a dumbbell infection
  • Palpate along FPL as it may be associated with FPL tenosynovitis
  • Dorsal extension through adductor pollicis and 1st DI
  • Can spread to the FPL/radial bursa
Q36What are the spread patterns and risks of a midpalmar space infection?▸
  • Communicates with the flexor sheath
  • Proximal extension to Parona's space; diffuse spread from Parona's space to radial/ulnar bursae, hypothenar and thenar spaces
  • Can cause median nerve compromise
Q37What are the boundaries and management of a hypothenar space infection?▸
  • Rare
  • Boundaries: palmar fascia and superficial hypothenar muscle fascia (superficial), 5th MC and deep hypothenar muscle fascia (deep), hypothenar septum (radial)
  • Rx: incision along the radial border of the hypothenar eminence
Q38How is wrist septic arthritis drained?▸
  • Longitudinal incision between the 3rd and 4th compartments (gold standard)
  • Arthroscopic: 2/3 + 4/5 portals (viewing + working), 6U/6R for water out
Q39What are the advantages and disadvantages of arthroscopic wrist drainage?▸
  • Advantages: small wound, preserves the dorsal ligament
  • Disadvantages: incomplete lavage, time-consuming
Q40How is MCPJ septic arthritis drained?▸
  • Dorsal approach, adjacent to the extensor tendon
  • Split the sagittal band
Q41How is PIPJ septic arthritis drained?▸
  • Dorsal: between the central slip and lateral band
  • Mid-axial: through accessory collateral
Q42How is DIPJ septic arthritis drained?▸
  • Dorsal: adjacent to the terminal extensor
  • Mid-axial: through accessory collateral
Q43Why is a wound over the MCPJ suspicious and what must be excluded?▸
  • Suspicious of a fight bite
  • Needs urgent exploration to rule out extension into the joint
  • Also exclude extensor tendon and osteochondral injuries
  • Neglected injuries are associated with fracture and osteomyelitis
Q44How do you examine a suspected fight bite?▸
  • Ask the patient to flex the MCPJ (mimic a punch)
  • This reveals the true tendon cut position
Q45What history is important in a fight bite?▸
  • Mechanism and chronicity
  • Occupation, hand dominance
  • Ask if the assailant has a history of blood-borne virus

Fact check

All four Kanavel signs positive gives >90% sensitivity for flexor tenosynovitis — conflates individual sign sensitivity with all four; misleading — individual Kanavel signs have 91-97% sensitivity but poor specificity (51-69%); all four are present in only a minority and are specific rather than >90% sensitive — source
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