High Yield Overview

SUPRACONDYLAR HUMERUS FRACTURE - CLOSED REDUCTION PERCUTANEOUS PINNING

Closed reduction with percutaneous K-wire pinning (lateral-entry or crossed pin configuration) for displaced pediatric supracondylar humerus fractures | intermediate

Critical Danger Structures - 5 Key Zones

Danger Zone 1: Ulnar Nerve

Location: 2-5mm posterior to medial epicondyle in cubital tunnel, 3-4mm deep to subcutaneous tissue

Protection: For medial pin insertion - extend elbow 45-60° (moves nerve posteriorly), mini-open 1cm incision preferred, palpate/visualize nerve, insert pin anterior to nerve under direct vision. Lateral-entry only technique avoids this risk entirely.

Injury Risk: 2-4% iatrogenic injury with percutaneous medial pin, less than 1% with mini-open visualization, 0% with lateral-entry only technique

Danger Zone 2: Anterior Interosseous Nerve

Location: Branch of median nerve passing deep to pronator teres 4-6cm distal to medial epicondyle, courses on interosseous membrane between FPL and FDP

Protection: No direct surgical risk (injured at presentation from stretching over fracture spike). Check preoperatively: OK sign (FPL), FDP index flexion, pronator quadratus function. Document carefully for medicolegal purposes.

Injury Risk: 10-20% at presentation (most common nerve injury), usually neurapraxia recovering spontaneously in 3-6 months, pure motor deficit (no sensory loss)

Danger Zone 3: Brachial Artery

Location: Crosses antecubital fossa 10-15mm anterior to distal humerus, tethered proximally by lacertus fibrosus and distally by deep head of pronator teres

Protection: Gentle reduction technique (avoid multiple attempts), assess pulse pre- and post-reduction, backslab elbow flexion less than 90° (70-80°) to avoid kinking artery at fracture site, especially with residual swelling.

Injury Risk: Kinked or compressed (pink pulseless) in 10-15% Gartland III (observe if pink hand), rarely lacerated less than 2% (requires exploration if white/pulseless)

Danger Zone 4: Median Nerve

Location: Runs medial to brachial artery 8-12mm anterior to distal humerus in antecubital fossa, proximal fragment can impale nerve with anterior displacement

Protection: Check preoperatively: thumb-index pinch strength, thenar muscle bulk/strength, sensation radial 3.5 fingers. Gentle reduction technique. Document pre/post-reduction status.

Injury Risk: 3-5% at presentation from direct injury by anterior displacement of proximal fragment, usually recovers with reduction

Danger Zone 5: Radial Nerve

Location: Posterior interosseous nerve branch passes around radial neck 15-20mm anterior to lateral epicondyle, superficial radial nerve courses anterolateral to elbow

Protection: Entry point for lateral pins should be on lateral epicondyle or posterior to avoid nerve (15-20mm anterior is danger zone). Check preoperatively: wrist/thumb extension, first webspace sensation.

Injury Risk: 3-5% at presentation (usually radial nerve), less than 1% iatrogenic with lateral pins if entry point chosen correctly

Mnemonic

No Angels In HeavenGARTLAND Classification Mnemonic

Memory Hook:Examiners expect precise distinction between IIA (stable) and IIB (unstable with rotation) - IIB requires surgery despite appearing well-aligned on AP view

Mnemonic

SAFE PINSAFE PIN Insertion Technique

Memory Hook:Describe pin configuration systematically - examiners probe understanding of biomechanics and why divergence/spread critical for preventing loss of reduction

Gartland Classification System

Type I - Nondisplaced

Anterior humeral line intersects capitellum on lateral radiograph
No angulation or rotation
Posterior fat pad sign may be only finding
Treatment: Above-elbow backslab, elbow 90° flexion
Outcome: Excellent, remodels completely

Type IIA - Angulated, Posterior Cortex Intact

Anterior humeral line passes anterior to capitellum
Extension angulation present
Posterior cortex intact (serves as hinge)
No rotation (medial/lateral columns aligned)
Baumann angle maintained within 5° of contralateral
Treatment: May attempt closed reduction and casting (controversial), many surgeons pin for reliability

Type IIB - Angulated and Rotated

Angulation in extension (anterior humeral line anterior to capitellum)
Rotation present (medial or lateral column malalignment)
Posterior cortex may appear intact on one view but disrupted on other
Loss of Baumann angle (varus or valgus tilt)
Treatment: CRPP mandatory - unstable fracture

Type III - Completely Displaced

No cortical contact between fragments
Periosteal hinge may be intact (usually posterior) or completely disrupted
High neurovascular injury risk (15-20% nerve injury, 10-15% vascular)
Treatment: Urgent CRPP within 6-8 hours
Compartment syndrome risk: 0.5-1%

Exam Pearl

Critical Distinction: Type IIA versus IIB - examiners focus here. IIA has angulation but NO rotation and intact posterior cortex on BOTH views. IIB has rotation (medial/lateral column malalignment) making it unstable despite appearing aligned on single view. IIB always requires surgery.

Neurovascular Examination Protocol

Document Pre-Reduction (Medicolegal Essential)

Anterior Interosseous Nerve (AIN) - Most common (10-20%)

Motor: FPL weak (thumb IP flexion) - OK sign lost
Motor: FDP index weak (index DIP flexion) - unable to flex DIP in isolation
Motor: Pronator quadratus weak (resisted pronation with elbow flexed)
Sensory: NONE (pure motor nerve)
Mechanism: Stretching over anterior spike of proximal fragment
Prognosis: 90% recovery over 3-6 months (neurapraxia)

Median Nerve - 3-5% at presentation

Motor: Thumb-index pinch weakness, thenar muscle atrophy (chronic)
Motor: FPL, FDP index/middle (overlap with AIN)
Sensory: Radial 3.5 fingers, thenar eminence
Mechanism: Direct injury from anterior displacement of proximal fragment
Prognosis: Usually recovers with reduction

Radial Nerve - 3-5% at presentation

Motor: Wrist extension weak (wrist drop), thumb extension weak
Motor: Finger MCP extension weak
Sensory: First webspace (superficial radial nerve)
Mechanism: Traction or direct injury
Prognosis: Usually recovers

Ulnar Nerve - 1% at presentation, 2-4% iatrogenic with medial pin

Motor: Finger abduction weak (interossei), Froment sign
Motor: Small finger abduction weak (ADM)
Sensory: Small finger ulnar half, ring finger ulnar half
Mechanism: Iatrogenic injury with medial pin insertion
Prognosis: Usually neurapraxia, recovers 3-6 months

Vascular Assessment

Radial pulse: Present, diminished, or absent
Capillary refill: Normal less than 2 seconds
Hand color: Pink versus white/pale
Hand temperature: Warm versus cool/cold
Pink pulseless hand (10-15%): Brachial artery kinked, adequate collaterals (radial/ulnar), safe to observe after reduction
White/pulseless hand: Brachial artery lacerated or severely compressed, requires urgent exploration if persists post-reduction

Pink Pulseless Hand Management

90% of pink pulseless hands develop adequate collaterals and do not require exploration. After reduction, if hand remains pink and warm with good capillary refill, observe closely. If hand becomes white, cold, or compartment syndrome develops, urgent exploration and possible fasciotomy required. Document pulse status meticulously pre- and post-reduction.

Radiographic Assessment Criteria

Lateral View - Anterior Humeral Line

Draw line along anterior cortex of humerus extending distally
Normal: Bisects middle third of capitellum
Abnormal: Passes through anterior third or entirely anterior to capitellum (extension deformity)
Post-reduction: MUST bisect middle third (essential quality indicator)

AP View - Baumann Angle

Angle between long axis of humerus shaft and line through capitellum physis
Normal: 70-75° (range 64-81°)
Compare to contralateral side (within 5° acceptable)
Less than 65°: Varus malreduction (medial tilt)
Greater than 80°: Valgus malreduction (lateral tilt)
Baumann angle less than 64° correlates with cubitus varus deformity

AP View - Medial and Lateral Columns

Medial column: Medial metaphyseal cortex should align with medial epicondyle
Lateral column: Lateral metaphyseal cortex should align with capitellum
Disruption indicates rotation (IIB or III fracture)

Gordon Line (AP View)

Line along anterior cortex of distal humerus
Should point toward capitellum ossification center
Disruption indicates rotation

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOStandard

EXAMINER

"A 6-year-old boy presents to ED 3 hours after falling off monkey bars. Radiographs show a completely displaced supracondylar humerus fracture. On examination he has a pink, pulseless hand with good capillary refill and cannot make an 'OK' sign with his thumb and index finger. Walk me through your management from presentation to discharge."

EXCEPTIONAL ANSWER

This is a Gartland Type III supracondylar fracture with vascular compromise (pink pulseless hand) and anterior interosseous nerve (AIN) injury. This requires urgent surgery within 6-8 hours. My approach is systematic: immediate neurovascular assessment, definitive fixation, and monitoring for compartment syndrome. **Immediate Assessment (ED)**: I perform comprehensive neurovascular examination documenting all five nerve territories. AIN deficit (cannot make OK sign, weak FPL and FDP index) is most common nerve injury (10-20%), typically neurapraxia from stretching over anterior fracture spike. Pink pulseless hand (10-15% Gartland III) indicates brachial artery kinked but adequate collaterals via radial/ulnar - acceptable to proceed with reduction and observe. I would examine for compartment syndrome (pain with passive finger extension, tense compartments). Radiographs confirm Gartland III (no cortical contact). **Urgent Surgical Planning**: List for urgent CRPP within 6 hours (vascular compromise present). Consent family: reduction technique, lateral versus crossed pins (I prefer lateral-entry only for safety), nerve injury risk if medial pin (2-4%), complications including compartment syndrome, expected recovery. NPO immediately, IV fluids, adequate analgesia, arm elevated, frequent neurovascular checks hourly. **Operative Technique**: General anesthesia with muscle relaxation mandatory. Supine on radiolucent hand table. Closed reduction sequence: longitudinal traction 2-3 minutes with elbow extended, correct varus (if present) with valgus force, flex elbow to 90° while applying posterior olecranon pressure, hyperflex to 120-140° and reassess pulse (reduce to 90° if pulse disappears). Fluoroscopy confirms reduction: lateral view (anterior humeral line bisects middle third capitellum), AP view (Baumann angle 70-75°, within 5° of contralateral). Three divergent lateral pins for stability (greater than 30° divergence, spread greater than 2cm at fracture, all engage medial cortex). Avoid medial pin (no ulnar nerve risk with lateral-entry only). Bend pins 90° and cut 0.5cm proud for clinic removal. **Critical Immobilization**: Above-elbow posterior backslab at 70-80° flexion (NOT hyperflexed - vascular kinking risk), forearm neutral. Collar and cuff for elevation. Post-reduction neurovascular exam documenting radial pulse return (if returns - excellent), confirm AIN deficit unchanged (not new). **Postoperative Monitoring**: Admit for 24-48 hours. Hourly neurovascular checks first 12 hours: radial pulse, capillary refill, hand color/temperature, pain assessment, compartment exam. If pink pulseless persists: Doppler confirming radial/ulnar flow, observe closely. If hand becomes white/cold or compartment syndrome (severe pain, pain with passive finger extension, tense compartments): Urgent fasciotomy all 3 forearm compartments. **Discharge and Follow-up**: Discharge when neurovascular status stable (48 hours). Strict precautions: return immediately if severe pain, numbness, white/cold hand. First clinic 5-7 days (radiographs confirm maintained reduction), second visit 3 weeks (pin removal in clinic if proud, radiographs), final visit 6-8 weeks (assess ROM, continue active exercises). Counsel family: AIN deficit (90% recover over 3-6 months), expect elbow stiffness initially (improves 6-12 months with active ROM only, no passive stretching).

VIVA SCENARIOStandard

EXAMINER

"You've completed closed reduction and lateral pinning of a Gartland Type III fracture. Final fluoroscopy shows the anterior humeral line passes through the anterior third of the capitellum on lateral view, and Baumann angle is 65° compared to 74° on the contralateral side. The pins are divergent, cross the fracture, and engage both cortices. What do you do?"

EXCEPTIONAL ANSWER

This is an inadequate reduction with residual extension deformity (anterior humeral line not bisecting middle third capitellum) and coronal plane malalignment (Baumann angle 65° versus 74° contralateral = 9° difference, varus malreduction). The pin configuration may be adequate but reduction quality is unacceptable. I would NOT accept this reduction and proceed with re-reduction before bending/cutting pins. **Recognition of Problem**: Acceptable reduction criteria: (1) Lateral view - anterior humeral line bisects middle third capitellum, (2) AP view - Baumann angle within 5° of contralateral, (3) Medial/lateral columns aligned. This case fails both (1) and (2). Anterior humeral line through anterior third indicates 10-15° extension deformity. Baumann angle 65° (versus 74°) is 9° varus malreduction (less than 64° predicts cubitus varus deformity). **Consequence of Accepting**: Extension malunion causes cosmetic/functional deficit (loss of terminal flexion, prominence of olecranon posteriorly). Varus malreduction of 9° will likely result in cubitus varus 'gunstock deformity' requiring corrective osteotomy. Patient/family dissatisfaction. Medicolegally indefensible to accept suboptimal reduction visible on fluoroscopy intraoperatively. **Immediate Action**: Remove all pins (do not bend/cut). Re-attempt closed reduction using systematic maneuver: longitudinal traction, correct varus with valgus force and thumb pressure on lateral condyle medially, flex elbow 90° with posterior olecranon pressure (translate distal fragment anteriorly), hyperflex to lock. If pulse disappears with hyperflexion, reduce to 90° and pin in that position. Assistant holds reduction while I assess fluoroscopy critically. **Re-assess Fluoroscopy**: Confirm anterior humeral line now bisects middle third capitellum (lateral view). Confirm Baumann angle now within 5° of contralateral (AP view). If still inadequate: consider open reduction (not satisfactory closed reduction achievable). **Re-pin if Adequate Reduction**: Three lateral divergent pins with technique as before (divergence greater than 30°, spread greater than 2cm at fracture, engage medial cortex). Reconfirm final radiographs both reduction AND pin configuration acceptable. Only then bend and cut pins. **Open Reduction Consideration**: If closed reduction remains inadequate after 2 attempts (anterior humeral line still anterior third or Baumann still greater than 5° from contralateral), proceed to open reduction. Approach: Lateral approach (Kocher interval between anconeus and EDC) allows direct visualization of fracture, removal of any soft tissue interposition (brachialis muscle most common), direct reduction under vision, pinning under direct control. **Communication**: Inform family postoperatively that additional reduction attempt was required to optimize alignment. Document clearly in operative note: initial inadequate reduction recognized, re-reduction performed, final radiographs acceptable. Cubitus varus risk reduced from high (with 9° varus) to low (with anatomic alignment).

VIVA SCENARIOStandard

EXAMINER

"You're pinning a Gartland III supracondylar fracture with crossed configuration (1 lateral + 1 medial pin). After inserting the medial pin with the elbow extended to 60°, you flex the elbow to assess final reduction on fluoroscopy and notice the patient's small finger is now dusky with poor capillary refill. The radial pulse remains palpable. What has happened and what is your management?"

EXCEPTIONAL ANSWER

This describes acute ulnar artery injury or occlusion, likely from the medial pin transfixing or compressing the ulnar artery as it courses medial and posterior to the medial epicondyle. The radial pulse remains palpable (radial artery intact) but ulnar artery supplies small finger predominantly via superficial palmar arch - dusky small finger indicates ulnar artery compromise. This requires immediate action. **Recognition**: Dual arterial supply to hand: radial artery (dominant, 50-60%) and ulnar artery (co-dominant, 40-50%). Superficial palmar arch (ulnar artery dominant) supplies small finger and ulnar half ring finger. Dusky small finger with palpable radial pulse = ulnar artery injury. Medial pin trajectory crosses ulnar artery as it passes posterior to medial epicondyle (8-10mm posterior, deep to FCU). **Immediate Action**: Remove medial pin immediately. Extend elbow again (flexion may kink vessels at fracture site). Reassess small finger color, capillary refill, and radial pulse. Perform Allen test (compress radial artery, assess hand perfusion via ulnar artery). If small finger color improves after pin removal, ulnar artery was compressed/transfixed by pin (not lacerated). If persists, consider arterial injury. **Intraoperative Assessment**: If small finger color returns to pink with good capillary refill after medial pin removal: ulnar artery spasm or compression from pin (resolved with removal). Assess whether medial pin is essential - if lateral pin(s) alone provide adequate stability (2-3 divergent lateral pins), proceed without medial pin (safer). If medial pin required for stability (highly unstable fracture, medial comminution): redirect medial pin more anteriorly (away from ulnar artery course) or convert to mini-open technique with direct visualization of neurovascular structures. **If Small Finger Remains Dusky**: Suggests ulnar artery laceration or thrombosis. Options: (1) Complete surgery with lateral pins only, then urgent vascular exploration medial elbow, repair/bypass ulnar artery, (2) Immediate vascular surgery consultation intraoperatively if available. Document radial pulse intact (hand will perfuse via radial artery alone in most cases, but ulnar artery repair optimal). **Complete Pinning**: If medial pin removed and not re-inserted, ensure lateral pins adequate: minimum 2 pins, preferably 3, divergent greater than 30°, spread at fracture greater than 2cm, engage medial cortex. Three lateral pins biomechanically equivalent to crossed configuration. Final fluoroscopy confirms reduction maintained, pins adequate. **Postoperative Management**: Close neurovascular monitoring. Document ulnar artery injury, medial pin removed, hand perfusion via radial artery. Small finger should pink up (radial artery supplies via deep/superficial palmar arches even if ulnar artery injured). If white/cold: Urgent vascular exploration, ulnar artery repair. Allen test postoperatively confirms radial artery alone adequate. **Communication**: Inform family of complication: medial pin caused temporary ulnar artery compromise, pin removed immediately, hand perfusion restored via radial artery, monitor closely. Most patients tolerate ulnar artery injury if radial artery intact (dual supply). Document in operative note: dusky small finger noted after medial pin insertion, pin removed immediately, color restored, completed with lateral pins only. **Learning Point**: This scenario highlights risk of medial pin - not only ulnar nerve (2-4%) but also ulnar artery. Lateral-entry only technique avoids this entirely. If medial pin chosen, mini-open approach with direct visualization of both ulnar nerve AND ulnar artery is safest.

Supracondylar Humerus Fracture CRPP - High-Yield Exam Summary

High-Yield Exam Summary

References

Gartland JJ. Management of supracondylar fractures of the humerus in children. Surg Gynecol Obstet. 1959;109(2):145-154. [Original description of Gartland classification system, foundational paper for supracondylar fracture management, defines Type I-III based on displacement pattern]
Skaggs DL, Cluck MW, Mostofi A, Flynn JM, Kay RM. Lateral-entry pin fixation in the management of supracondylar fractures in children. J Bone Joint Surg Am. 2004;86(4):702-707. doi:10.2106/00004623-200404000-00006 [Demonstrates biomechanical adequacy of lateral-entry only pinning with 2-3 divergent pins, safety advantage avoiding ulnar nerve]
Brauer CA, Lee BM, Bae DS, Waters PM, Kocher MS. A systematic review of medial and lateral entry pinning versus lateral entry pinning for supracondylar fractures of the humerus. J Pediatr Orthop. 2007;27(2):181-186. doi:10.1097/bpo.0b013e3180316cf2 [Meta-analysis showing crossed pins superior biomechanical stability but 2-4% iatrogenic ulnar nerve injury versus 0% lateral-entry only]
Shaw BA, Kasser JR, Emans JB, Rand FF. Management of vascular injuries in displaced supracondylar humerus fractures without arteriography. J Orthop Trauma. 1990;4(1):25-29. doi:10.1097/00005131-199003000-00005 [Landmark paper establishing safety of observing pink pulseless hand after reduction, 90% develop adequate collaterals, arteriography/exploration not routinely needed]
Choi PD, Melikian R, Skaggs DL. Risk factors for vascular repair and compartment syndrome in the pulseless supracondylar humerus fracture in children. J Pediatr Orthop. 2010;30(1):50-56. doi:10.1097/BPO.0b013e3181c6b3a8 [Analysis of 165 pulseless hands: pink hand observe (90% good outcome), white hand 70% require exploration, compartment syndrome 0.5-1%]
Ramachandran M, Skaggs DL, Crawford HA, et al. Delaying treatment of supracondylar fractures in children: has the pendulum swung too far? J Bone Joint Surg Br. 2008;90(9):1228-1233. doi:10.1302/0301-620X.90B9.20728 [Study demonstrating increased complications with surgical delay greater than 8 hours, recommends urgent surgery within 6-8 hours for Gartland III]
Valencia M, Moraleda L, Díez-Sebastián J. Long-term functional results of neurological complications of pediatric supracondylar humeral fractures. J Pediatr Orthop. 2015;35(6):606-610. doi:10.1097/BPO.0000000000000333 [Natural history of nerve injuries: AIN recovers 90% by 6 months, median 80%, radial 85%, ulnar 75%, most neurapraxia not requiring exploration]
Wilkins KE, Beaty JH, Chambers HG, Toniolo RM. Fractures and dislocations of the elbow region. In: Rockwood CA, Wilkins KE, Beaty JH, eds. Fractures in Children. 4th ed. Philadelphia: Lippincott-Raven; 1996:653-904. [Comprehensive textbook chapter detailing anterior humeral line, Baumann angle measurement, acceptable reduction criteria, historical evolution of treatment]
Omid R, Choi PD, Skaggs DL. Supracondylar humeral fractures in children. J Bone Joint Surg Am. 2008;90(5):1121-1132. doi:10.2106/JBJS.G.01354 [Current concepts review covering classification, neurovascular assessment, reduction techniques, pinning configurations, complications including cubitus varus prevention]
Gottschalk HP, Sagoo D, Glaser D, Doan J, Edmonds EW, Schlechter J. Biomechanical analysis of pin placement for pediatric supracondylar humerus fractures: does starting point, pin size, and number matter? J Pediatr Orthop. 2012;32(5):445-451. doi:10.1097/BPO.0b013e318257d1cd [Biomechanical study showing 3 lateral pins equivalent to crossed configuration, pin divergence greater than 30° and spread greater than 2cm at fracture critical for rotational stability]

Supracondylar Humerus Fracture - Closed Reduction Percutaneous Pinning