Distal humerus fracture (adult)

The distal humerus is a triangle of two columns (medial and lateral) joined by the trochlea, with the capitellum in front of the lateral column. In adults most fractures are articular (13C): the olecranon is driven up like a wedge and splits the condyles apart. Two age peaks: young men after high-energy trauma and elderly women with osteoporotic bone after a simple fall.

Mechanism

Fall onto the flexed elbow (the olecranon wedges the columns apart) or onto the outstretched hand; high-energy road and sports injuries, often open.

Clinical findings

• Swollen, deformed elbow; the epicondyle–olecranon triangle is preserved in supracondylar fractures but disturbed in dislocations and in fractures that split the condyles.
• Ulnar nerve function before any treatment (and document it); radial and median nerves, radial pulse.
• Posterior wounds from the shaft spike = open fracture. Watch for forearm compartment syndrome.

Imaging

• AP and lateral of the elbow; full-length humerus if the fracture extends up the shaft.
• Traction views under anaesthesia when comminution is hard to read.
• CT with 3D reconstructions for every articular fracture and for any capitellar or trochlear shear (double-arc sign).

• AP and lateral of the elbow; traction views under anaesthesia help to understand comminution.
• CT with 3D reconstructions for all articular fractures, and to show coronal shear fractures of the capitellum and trochlea (double-arc sign on the lateral X-ray).

Classification

13A

Extra-articular: A1 epicondyle avulsion, A2 simple metaphyseal, A3 wedge or multifragmentary metaphyseal.

13B

Partial articular: B1 lateral sagittal (lateral condyle), B2 medial sagittal (medial condyle), B3 frontal/coronal plane (capitellum and/or trochlea).

13C

Complete articular: C1 simple articular and simple metaphyseal (T or Y), C2 simple articular with multifragmentary metaphysis, C3 multifragmentary articular.

Capitellum (Bryan–Morrey / Dubberley)

I Hahn–Steinthal (large osseous fragment), II Kocher–Lorenz (thin osteochondral shell), III comminuted, IV (McKee) capitellum and trochlea in one piece; Dubberley adds whether the posterior condyle is comminuted.

Types shown in 3D

13A2

Extra-articular simple metaphyseal (supracondylar) fracture: the distal block and the forearm go posteriorly and proximally under triceps pull. Double plating, or a single strong plate in good bone.

13B1

Lateral sagittal: the lateral condyle with the capitellum and part of the trochlea is sheared off and displaced proximally; the forearm may follow it. Screws and a lateral plate.

13B2

Medial sagittal: the medial condyle and trochlea, pulled by the flexor–pronator mass. The ulna may sublux with it. Screws and a medial plate; protect the ulnar nerve.

13B3 capitellum

Coronal shear of the capitellum (Hahn–Steinthal type): the fragment flips forwards and up into the radial fossa and can block flexion. Seen as a half-moon in front of the humerus on the lateral view. Headless compression screws.

13C1

Complete articular, simple (T or Y): a supracondylar line plus a sagittal split between the trochlea halves. The ulna is driven up between the condyles and they rotate apart. Restore the joint, then double plating.

Treatment

Open reduction and internal fixation (standard)

For almost all displaced fractures in patients who can use the arm. Posterior approach (olecranon osteotomy for C3, triceps-sparing or triceps-splitting for simpler patterns), identify and protect the ulnar nerve. Restore the joint first, then fix it to the shaft with two precontoured plates (orthogonal or parallel) so that each column is stable and early motion is possible.

Capitellum and trochlea (13B3)

Lateral (Kocher or Kaplan) approach; headless compression screws from anterior to posterior, or posterior to anterior with a posterolateral buttress plate when the posterior condyle is comminuted.

Total elbow arthroplasty

Elderly, low-demand patients with unreconstructable articular comminution in osteoporotic bone (and rheumatoid arthritis): linked (semi-constrained) prosthesis. Lifelong lifting limit of a few kilograms.

Non-operative

Only for undisplaced fractures or patients who cannot undergo surgery ("bag of bones": short splinting and early motion, accepting stiffness).

Aftercare

Splint in extension for a few days, then active-assisted motion within the first week after stable fixation. No strengthening before union (about 12 weeks).

Complications

• Stiffness, especially loss of extension (the commonest problem)
• Ulnar neuropathy
• Heterotopic ossification
• Non-union (supracondylar level) and failure of fixation
• Olecranon osteotomy non-union or symptomatic wires
• Post-traumatic arthritis