Lateral Condyle Fracture of Humerus in Children
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Direct answer
A lateral condyle fracture of the humerus is the second most common elbow fracture in children, after supracondylar fracture, and it passes through the largely cartilaginous lateral condyle. Management depends on the Milch classification, which separates fractures that spare the trochlea from those that run through it, and on how far the fragment has displaced. Unstable fragments need reduction and internal fixation, because nonunion and valgus deformity can follow.
What you must remember
- Mechanism: a fall on the outstretched hand, which tears the lateral condyle through the growth cartilage of the distal humerus.
- Milch type I: the fracture line runs lateral to the trochlea, so the articular surface stays intact and the fragment is usually stable.
- Milch type II: the fracture line runs through the trochlea, so the articular surface is disrupted and the fragment tends to rotate and displace.
- Jakob grading: stage 1 is undisplaced with an intact cartilage hinge, stage 2 is displaced and stage 3 is displaced with fragment rotation; a cut-off of about 2 mm differs between sources and helps decide between nonoperative and operative care.
- Treatment: undisplaced fragments are immobilised in a cast, while displaced or unstable fragments are reduced and fixed with pins or screws.
- Complications: nonunion, growth disturbance, cubitus valgus and tardy ulnar nerve palsy, with avascular necrosis rarely reported.
- Radiology: the fragment is largely cartilaginous, so it can be missed on plain films and may need an arthrogram or ultrasound.
From a painful elbow to a stable fixation
A 7-year-old girl falls on her outstretched hand and has a swollen elbow with tenderness over the lateral side. The X-ray shows a small, possibly displaced fragment, and the key decisions are whether the fragment has moved and whether the joint surface is involved.
- Document the nerves and pulses: assess the median, radial and ulnar nerves and the distal pulses before any manipulation, and record the findings.
- Obtain adequate views: anteroposterior and lateral radiographs, with an oblique view if the fragment is hard to see, since cartilage can make the fragment look smaller than it is.
- Classify by Milch: decide whether the fracture line lies lateral to the trochlea (Milch I) or runs through it (Milch II).
- Measure the displacement: stage the fragment by Jakob's grades and measure displacement, since roughly 2 mm is a commonly quoted threshold for surgery, though sources differ.
- Fix unstable fragments: after reduction, fix displaced or unstable fragments with screws or K-wires and immobilise the elbow in a cast.
- Follow up for healing and growth: repeat radiographs check union, the carrying angle and the physis, because nonunion and valgus deformity can develop over months.
Viva angles on displacement and valgus
Examiners often ask how the classification changes management and what follow-up detects.
- Trap: treating every lateral condyle fracture as undisplaced. Correct: the cartilaginous fragment can look minimally displaced on plain X-ray, so an arthrogram or ultrasound is used when in doubt.
- Trap: calling every Milch type I fracture unstable. Correct: type I fractures keep the trochlea intact, and an undisplaced one usually heals with immobilisation alone.
- Trap: ignoring the carrying angle at follow-up. Correct: nonunion and growth disturbance can produce cubitus valgus and tardy ulnar nerve palsy, so the carrying angle and ulnar nerve are checked at review.
Frequently asked questions
What is the Milch classification of lateral condyle fractures?
The Milch classification divides lateral condyle fractures into type I and type II according to the fracture line in relation to the trochlea. Type I lies lateral to the trochlea and is usually stable, while type II passes through the trochlea, disrupts the articular surface and is generally unstable.
What complications follow a lateral condyle fracture of the humerus?
Nonunion, growth disturbance and cubitus valgus are the main complications of a lateral condyle fracture of the humerus. Tardy ulnar nerve palsy can develop with valgus deformity, and avascular necrosis is rarely reported.
At what displacement is fixation considered for a lateral condyle fracture?
Surgeons commonly fix fragments displaced by more than about 2 mm, and fragments that involve the trochlea are also treated operatively. The threshold is a guide rather than a rigid rule, and the decision depends on the fracture pattern and the child's age.
Why is a lateral condyle fracture often missed on X-ray?
The lateral condyle is largely cartilaginous at the age when the fracture occurs, so the ossified fragment on a plain film can underestimate the true injury. An arthrogram or ultrasound can reveal the cartilaginous component when the radiograph is inconclusive.
Which nerve injury is linked with cubitus valgus after lateral condyle fracture?
Tardy ulnar nerve palsy is the nerve injury linked with cubitus valgus after lateral condyle fracture of the humerus. It develops slowly, often years later, because the valgus carrying angle stretches the ulnar nerve in the cubital tunnel.