Open reduction internal fixation via Kocher approach preserving posterior blood supply | intermediate
Surgical Imaging
The trap: The lateral condyle fragment appears to have robust soft-tissue attachments laterally — surgeons may be tempted to release posterior tissues for better visualisation.
The fix: The entire blood supply arrives via posterior structures. Maintain a strict anterior-only dissection plane. Leave the posterior periosteal hinge and capsule completely undisturbed. Avascular necrosis of the capitellum or trochlea is almost always iatrogenic from posterior dissection.
The trap: Judging reduction by the metaphyseal spike or external cortex alone — the articular surface may remain stepped even when the metaphysis looks aligned.
The fix: Always visualise the anterior articular surface directly through the Kocher interval. Reduce under direct vision and confirm with image intensifier in multiple planes. A step greater than 1 mm at the joint surface is unacceptable and predicts later arthritis or nonunion.
The trap: Treating a Milch type II fracture (through the trochlear groove) as a simple lateral condyle injury — these are functionally equivalent to a T-condylar fracture with complete loss of trochlear support.
The fix: Type II fractures have no intact articular hinge. They displace in three planes and almost always require open reduction. Do not attempt closed reduction in type II injuries.
The trap: Defaulting to K-wires in every case — in older children with larger fragments a screw provides compression and earlier motion but risks physeal damage if placed across the growth plate.
The fix: In children younger than 8 years or with small fragments use divergent smooth K-wires. In older children (greater than 10 years) with a large fragment a 4.0 mm cannulated screw placed from posterior to anterior or lateral to medial, avoiding the physis, allows earlier range-of-motion exercises.
The trap: Operating on an established nonunion (greater than 12 weeks) with the same acute fracture protocol — the fragment is sclerotic, the bed is atrophic, and simple pinning will fail.
The fix: Late nonunion requires freshening of sclerotic edges, autograft or allograft, and stable compression fixation (often a screw plus tension-band wiring). Ulnar nerve transposition is frequently required at the same sitting because of valgus deformity and tardy neuropathy.
The trap: Missing the early radiographic sign of fishtail deformity — central physeal bar formation between capitellum and trochlea leading to a characteristic notch.
The fix: On the AP radiograph at 6-12 months look for loss of the normal smooth contour between capitellum and trochlea. Early recognition allows discussion of future deformity correction or ulnar nerve management before severe valgus and palsy develop.
M.I.L.C.HMILCH — Fracture Classification
K.O.C.H.E.RKOCHER — Surgical Approach Safety
W.E.I.S.SWEISS — Treatment Algorithm
Surgical Indications
Absolute Indications
- Displacement greater than 2 mm on any radiographic view
- Milch type II fracture through the trochlear groove
- Weiss type 3 injury (greater than 4 mm displacement or disrupted articular hinge)
- Open fracture or associated vascular injury
- Incarcerated fragment blocking motion
Relative Indications
- Weiss type 2 (2-4 mm) with equivocal hinge integrity on arthrogram
- Delayed presentation less than 3 weeks with still-mobile fragment
- Associated radial head or olecranon fracture requiring simultaneous fixation
- Patient or family preference for definitive anatomic reduction over nonoperative care
Contraindications
Absolute:
- Established nonunion greater than 12 weeks without preparation for grafting and compression (different operative plan)
- Active infection at the surgical site
Relative:
- Minimally displaced fracture (less than 2 mm) with intact hinge on advanced imaging
- Medical comorbidities precluding anaesthesia in the acute window
Evidence for Operative Treatment
Why Nonoperative Treatment Fails When Displaced
- The lateral condyle fragment has a small metaphyseal component and relies on the posterior soft-tissue pedicle for perfusion.
- Greater than 2 mm displacement allows synovial fluid to enter the fracture line, preventing healing and promoting nonunion.
- Malunion produces progressive cubitus valgus, lateral spur formation, and eventual tardy ulnar nerve palsy.
- Historical series before modern fixation showed nonunion rates approaching 30-50 percent when displacement exceeded 2 mm and nonoperative care was pursued.
Timing of Surgery
- Ideally within 5-7 days of injury while the fragment remains mobile and the fracture surfaces are fresh.
- Surgery after 3 weeks becomes technically more difficult due to early callus and fragment rounding; after 12 weeks it is considered established nonunion requiring a different strategy.
- Delayed presentation between 3 and 12 weeks still allows acute-style fixation but requires more aggressive debridement of early callus and careful assessment of fragment viability.
Fixation Method Evidence
- Two divergent smooth K-wires remain the most common fixation in children younger than 8-10 years because they avoid physeal damage and allow easy removal.
- A single 4.0 mm cannulated screw provides interfragmentary compression and earlier motion in older children with larger fragments; biomechanical studies show superior torsional stability compared with K-wires.
- Both techniques achieve greater than 90 percent union when anatomic reduction and posterior hinge preservation are achieved.
- Recent series support screw fixation in children older than 10 years with fragment size permitting screw placement without physeal violation, allowing earlier protected motion and potentially lower stiffness rates.
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“A 6-year-old child presents 5 days after a fall with a displaced lateral condyle fracture. The AP radiograph shows 3 mm displacement and the fracture line appears to pass through the trochlear groove. What is your classification, and what operative steps are critical to avoid avascular necrosis?”
“A 9-year-old presents 4 months after nonoperative treatment of a lateral condyle fracture with established nonunion, 15 degrees of cubitus valgus and early ulnar nerve paresthesias. Outline your surgical plan.”
“During Kocher approach for a fresh lateral condyle fracture you notice the radial nerve is immediately adjacent to your proximal dissection. How do you protect it and what is the safe zone?”