ABPS Surgery of the Hand cheat sheet

Syndactyly timing: border digits (thumb–index, ring–small) are released at 12–18 months to prevent angular deformity; central digits at 18–24 months; release before 6 months increases stiffness and web creep.

Simple syndactyly shares only soft tissue; complex syndactyly shares bone. Use interdigitating zigzag flaps and full-thickness skin grafts from the groin to line the new commissure.

Pediatric trigger thumb presents with an interphalangeal flexion contracture and a Notta nodule at the A1 pulley; most resolve spontaneously by 12–24 months, so A1 pulley release is reserved for persistent cases.

Blauth classification of thumb hypoplasia: grades I–II are reconstructable; grade IIIB (unstable CMC joint) through grade V are treated by ablating the remnant and performing index finger pollicization.

Radial longitudinal deficiency requires preoperative screening for Fanconi anemia (complete blood count, chromosome breakage), VACTERL association (cardiac, renal, vertebral) and Holt-Oram syndrome before centralization.

Brachial plexus birth palsy: Erb (C5–C7) gives a waiter's-tip posture, Klumpke (C8–T1) gives a clawed hand with Horner syndrome; absence of biceps function by 3–6 months indicates nerve reconstruction.

Camptodactyly most often affects the small finger PIP joint; observation and splinting come first, and operative release is considered when the flexion contracture exceeds roughly 30–40 degrees or splinting fails.

Constriction band syndrome from amnion rupture is treated by staged Z-plasty or excision of each band; release of a circumferential band in a single stage risks lymphatic and vascular compromise of the digit.

The scaphoid's blood supply enters the distal dorsal ridge from the dorsal branch of the radial artery, so proximal pole fractures carry the highest risk of nonunion and avascular necrosis.

Suspected scaphoid fracture with negative radiographs: immobilize, repeat imaging in 1–2 weeks, or obtain MRI/CT; anatomic snuffbox and scaphoid tubercle tenderness are the key clinical findings.

Distal radius patterns: Colles (dorsal angulation), Smith (volar angulation), Barton (intra-articular rim fragment), die-punch (impacted lunate facet fragment).

First metacarpal base: Bennett fracture is a two-part intra-articular fracture with a volar-ulnar fragment held by the anterior oblique ligament; Rolando fracture is comminuted (Y- or T-shaped).

Acceptable volar angulation for metacarpal neck fractures is about 40 degrees in the small finger and 10–15 degrees in the index finger; any rotational malalignment is unacceptable.

Stener lesion: the adductor aponeurosis interposes between a torn ulnar collateral ligament and the proximal phalanx, blocking healing; it requires operative repair of gamekeeper's thumb.

Perilunate and lunate dislocations follow a progressive perilunar arc; the perilunate form usually reduces closed and is pinned, whereas lunate dislocations often need open reduction, and the median nerve must be assessed.

Compartment syndrome is suggested by a delta pressure (diastolic pressure minus compartment pressure) below 30 mmHg; urgent fasciotomy is indicated rather than waiting for pulselessness.

LOAF muscles (median nerve): first and second lumbricals, opponens pollicis, abductor pollicis brevis, and the superficial head of flexor pollicis brevis; thenar atrophy signals advanced disease.

The ulnar nerve supplies all intrinsic hand muscles except LOAF; Froment sign (thumb IP flexion on pinch) and Wartenberg sign (abducted small finger) indicate intrinsic weakness.

Seddon classification: neurapraxia (demyelination, full recovery), axonotmesis (axon loss with intact endoneurium, good recovery), neurotmesis (complete transection, poor without surgery).

Regeneration advances at roughly 1 mm/day, approximated clinically by the advancing Tinel sign after axonotmesis or repair.

Repair is epineurial or group fascicular, performed tension-free; nerve graft (sural) is used when a gap cannot be closed, and conduit for short gaps in small-caliber digital nerves.

Carpal tunnel syndrome: nocturnal numbness, thenar atrophy, positive Phalen and Durkan tests; release divides the transverse carpal ligament while protecting the recurrent motor branch.

Cubital tunnel syndrome involves Osborne's ligament and worsens with prolonged elbow flexion; options are in situ decompression, medial epicondylectomy, or anterior transposition.

Guyon's canal lesions spare dorsal ulnar sensation because the dorsal sensory branch arises proximally; causes include ulnar artery aneurysm, ganglion, and hook of hamate fracture.

Flexor zones I–V: zone I is distal to the FDS insertion, zone II is within the fibro-osseous sheath where both tendons lie together (historically the worst prognosis), zone V is proximal to the carpal canal.

Extensor zones I–IX: zone I over the DIP (mallet), zone III over the PIP, zone V over the MCP joint, zone VII under the extensor retinaculum, zone VIII in the distal forearm.

Flexor repair uses a multi-strand core suture (four-strand or more) plus an epitendinous running stitch to reduce gap formation and allow early controlled mobilization.

Rehabilitation: Kleinert protocol uses passive flexion by rubber-band traction with active extension; Duran protocol uses controlled passive flexion with a dorsal blocking splint.

Trigger finger is A1 pulley stenosis; corticosteroid injection is first-line, and surgical release is favored in insulin-dependent diabetes and after failed injections.

Vaughan-Jackson lesion is attritional rupture of the extensor pollicis longus over Lister's tubercle after a minimally displaced distal radius fracture, causing loss of thumb IP extension.

Tendon transfer principles: supple joints, adequate donor excursion and strength (Grade 4–5), straight-line pull, one transfer per function, and tensioning with the wrist in neutral.

Quadriga effect: the four FDP tendons share one muscle belly, so excessive excursion or tethering of one digit weakens flexion in the others; limit distal advancement.

Osteoarthritis favors the DIP (Heberden nodes), PIP (Bouchard nodes), first carpometacarpal and scaphotrapezial joints; rheumatoid arthritis favors the MCP, wrist and PIP joints with ulnar drift.

Eaton staging of thumb CMC osteoarthritis (I–IV): stage IV includes scaphotrapezial disease and is best treated with trapeziectomy with or without ligament reconstruction, not ligament reconstruction alone.

SLAC wrist progresses from radial styloid–scaphoid arthritis to the entire scaphoid fossa and then capitolunate arthritis; stages II–III are treated with proximal row carpectomy or four-corner fusion.

Proximal row carpectomy requires an intact lunate facet of the radius and an intact capitate head; if either is arthritic, four-corner fusion is preferred.

Rheumatoid MCP disease is treated with silicone (Swanson) arthroplasty and realignment of the extensor tendons, whereas the DIP joint is usually arthrodesed.

Swan neck deformity is PIP hyperextension with DIP flexion from intrinsic tightness or volar plate laxity; boutonniere is PIP flexion with DIP extension from central slip failure.

Rheumatoid wrist destruction may be addressed with radiolunate fusion, total wrist arthrodesis, or total wrist arthroplasty depending on contralateral wrist status and demands.

Gout and calcium pyrophosphate disease mimic infection; aspirate for crystals and organisms before assuming a septic joint.

Ganglion cyst is the most common mass in the hand, typically dorsal over the scapholunate interval or volar at the radiocarpal joint; treatment is observation, aspiration, or excision.

Enchondroma is the most common benign bone tumor of the hand, usually in the phalanges and often revealed by pathologic fracture; multiple lesions suggest Ollier disease or Maffucci syndrome.

Giant cell tumor of tendon sheath is the second most common soft-tissue mass of the hand; it is lobulated and firm and recurs in roughly 10–20% of cases after excision.

Glomus tumor is a subungual lesion causing paroxysmal pain and cold sensitivity; the Love pin test and Hildreth test localize it, and MRI helps before excision.

Squamous cell carcinoma is the most common primary malignancy of the hand and may present subungually mimicking infection; melanoma carries a poor prognosis when delayed.

Epidermal inclusion cyst follows penetrating trauma and appears as a slowly enlarging nodule; rupture can produce a foreign-body inflammatory reaction.

Osteoid osteoma causes night pain relieved dramatically by NSAIDs, with a small radiolucent nidus surrounded by sclerosis on imaging.

Red flags for malignancy: rapid growth, size over 5 cm, deep or fixed location, pain, recurrence after excision; obtain MRI and biopsy before definitive resection.

Kanavel's four cardinal signs of pyogenic flexor tenosynovitis: fusiform swelling, semi-flexed resting posture, tenderness along the sheath, and severe pain on passive extension.

Felon is a closed-space infection of the distal pulp; it threatens pressure necrosis of the fingertip and osteomyelitis of the distal phalanx and requires prompt drainage.

Paronychia is usually caused by Staphylococcus aureus (including MRSA); herpetic whitlow is viral and must not be surgically drained.

Animal bites: Pasteurella multocida from cats and dogs; human bites: Eikenella corrodens. Amoxicillin-clavulanate covers both, and cat bites are high risk because of deep puncture inoculation.

Fight bite (clenched-fist injury) over the MCP joint inoculates oral flora into the joint or extensor tendon; treat with exploration, culture, antibiotics, and splinting, not simple suture.

Necrotizing fasciitis presents with pain out of proportion, rapid spread, crepitus, and gas on imaging; emergency wide debridement is the treatment, with antibiotics as an adjunct.

Mycobacterium marinum (fish tank exposure) and Sporothrix (rose gardener) cause chronic indolent granulomatous infection; diagnosis requires tissue culture and biopsy.

Deep space infections include thenar, midpalmar, hypothenar, and Parona's space; a collar-button abscess crosses the web space between these compartments and needs drainage on both sides.

Replantation is most strongly indicated for thumb amputation, multiple digits, wrist or forearm level, and any amputation in a child; a single digit distal to the FDS insertion is a relative indication.

Warm ischemia tolerance is roughly 6–12 hours for muscle-bearing parts; cooling to 4 °C extends tolerance to about 12–24 hours, and digits tolerate longer ischemia than the forearm.

Sequence for replantation: debridement, skeletal fixation, extensor tendons, arterial repair, venous repair, nerve repair, flexor tendons, then skin coverage.

Venous congestion after replantation is managed with leech therapy, release of tight dressings, and, if persistent, venous revision; arterial insufficiency requires re-exploration.

Hypothenar hammer syndrome is ulnar artery thrombosis or aneurysm from repeated palmar trauma, causing ischemia of the ring and small fingers with an abnormal Allen test.

Allen test assesses the adequacy of the palmar arch and collateral flow before radial or ulnar artery harvest or cannulation.

Stump management aims to preserve length and achieve soft-tissue coverage over bone; neuroma prevention options include targeted muscle reinnervation and regenerative peripheral nerve interfaces.

Ring avulsion severity (Urbaniak classification) depends on whether circulation is intact, insufficient, or absent; complete degloving with arterial failure requires revascularization or amputation.

Dupuytren disease begins as palmar nodules in the pretendinous cord; MCP joint contractures are more easily corrected than PIP contractures, and PIP involvement has a worse prognosis.

Diathesis predicting recurrence: young age at onset, bilateral disease, positive family history, knuckle pads (Garrod pads), and ectopic deposits; these favor more aggressive treatment.

A positive Hueston tabletop test (patient cannot lay the palm flat) is a functional indication for intervention.

Treatment options are limited fasciectomy, needle aponeurotomy, and collagenase injection; needle aponeurotomy and collagenase have higher recurrence rates but faster recovery.

Surgical risks in Dupuytren surgery include digital nerve injury, hematoma, flare reaction, skin necrosis, and stiffness; Z-plasty or skin grafting is used for severe or recurrent disease.

Fingertip coverage: Atasoy V-Y advancement for transverse or dorsal oblique amputations, Kutler lateral advancement flaps, and thenar flap for index or middle fingertip loss.

Exposed tendon without paratenon, exposed bone without periosteum, or exposed joint requires flap coverage rather than a skin graft.

Regional options include Moberg volar advancement (thumb), cross-finger flap, first dorsal metacarpal artery (kite) flap, posterior interosseous artery flap, radial forearm flap, and groin flap.