A distal humerus fracture is a fracture of the distal humeral metaphysis and articular surface, crossing the medial and lateral columns that carry the trochlea and capitellum. Most are treated by open reduction and dual plating. A comminuted intra-articular fracture in a low-demand older patient may do better with a total elbow replacement.
Key takeaways
- AO Surgery Reference sorts distal humerus fractures into extra-articular, partial articular and complete articular groups; McKee's trial recruited the complete articular pattern, coded OTA type 13C.
- McKee's randomised trial of 42 patients aged over 65 found total elbow arthroplasty gave better Mayo Elbow Performance Scores than fixation at 3 months (83 versus 65), 6 months, 12 months and 2 years (86 versus 73).
- Five of the 21 patients randomised to fixation in that trial were converted to arthroplasty during the operation because the comminution would not hold stable fixation.
- Research by Shearin and colleagues pooled 362 patients and found ulnar neuropathy in 19.3% overall, 15.3% after in situ release and 23.5% after anterior transposition.
- The December 2021 BOAST on peripheral nerve injury requires a recorded nerve examination at the first opportunity after injury, after any cast or manipulation, and before and after surgery.
- The May 2019 BOAST on the older or frail trauma patient asks for surgery within 36 hours of admission and a frailty pathway beginning within 72 hours of injury.
How is a distal humerus fracture classified?
A distal humerus fracture sits in AO segment 13, and AO Surgery Reference sorts it into three groups: extra-articular, partial articular and complete articular.
McKee's randomised trial defined its population as OTA type 13C, the complete articular pattern, which is the fracture the ST3 panel most often puts on the screen.
In practice the interviewer wants the column description rather than the code: a distal humerus fracture involving the medial column, the lateral column, or both, with or without an articular split.
Distal humerus fractures follow two populations. Young patients arrive after high-energy trauma, and older patients after a simple fall onto a flexed elbow with osteoporotic bone.
Why does the ulnar nerve matter in a distal humerus fracture?
The ulnar nerve runs in the cubital tunnel behind the medial epicondyle, directly through the field of any medial approach to a distal humerus fracture, so it is injured by the fracture or by the surgeon.
Research by Shearin and colleagues, a meta-analysis of five studies and 362 patients, found ulnar neuropathy after distal humerus fracture fixation in 19.3% overall.
In that analysis the rate was 15.3% where the nerve was released in situ and 23.5% where it was transposed anteriorly, so transposition did not protect it.
A larger systematic review by Li and colleagues, covering 17 studies and 1,280 patients with distal humerus fractures, found no significant difference in ulnar neuritis between transposition and no transposition.
That said, the same review found anterior transposition added a mean of 20.35 minutes to the operation, which is the argument the panel expects you to make.
How should a distal humerus fracture be assessed and imaged?
Assessment of a distal humerus fracture starts with the whole patient if the mechanism was high energy, then the limb: skin, compartments, radial pulse, and a documented examination of the radial, median and ulnar nerves.
The December 2021 BOAST on peripheral nerve injury states that an examination of all the functions of a peripheral nerve should be carried out and recorded at the first opportunity after injury.
The same standard requires that examination to be repeated after any intervention to the limb, such as manipulation or application of a cast, and recorded in enough detail to compare confidently later.
Imaging of a distal humerus fracture is orthogonal radiographs first, then CT for any articular involvement, because the articular map decides the approach and the implants.
Frailty is part of the assessment. The May 2019 BOAST includes patients with a Clinical Frailty Scale of 5 or more after major trauma, and every patient admitted with a fragility fracture.
What is the initial management of a distal humerus fracture?
Initial management of a closed distal humerus fracture is analgesia, an above-elbow backslab with the elbow at about 90 degrees, elevation, and a repeated documented nerve examination afterwards.
NICE NG38 states that adults with suspected long bone fractures of the arm should receive oral paracetamol for mild pain, paracetamol with codeine for moderate pain, and intravenous paracetamol with titrated intravenous morphine for severe pain.
NICE NG38 also says intravenous opioids should be used with caution in frail or older adults, and that non-steroidal anti-inflammatory drugs should not be offered to them at all.
An open distal humerus fracture follows the December 2017 BOAST on open fractures: early intravenous antibiotics, photograph and cover the wound, and plan a combined orthoplastic debridement.
How is a distal humerus fracture fixed, and what does the evidence say?
A distal humerus fracture is usually fixed with two plates, one on each column, either in a parallel configuration on the medial and lateral surfaces or in an orthogonal configuration.
A pooled analysis published in January 2026 compared the two configurations across six studies and reported better Mayo Elbow Performance Scores with parallel plating at 6, 12 and 24 months.
The same analysis reported union at a pooled 19.59 weeks for parallel plating against 22.96 weeks for orthogonal plating, roughly three weeks earlier, although the included studies were small.
Exposure of a complete articular distal humerus fracture usually needs an olecranon osteotomy, while an extra-articular pattern can be reached through a triceps-sparing approach that leaves the joint alone.
The principle the panel wants is stable fixation of both columns to the shaft, anatomical reconstruction of the articular surface, and an elbow that can start moving on the first postoperative day.
When is total elbow arthroplasty the better option?
Total elbow arthroplasty is the better option for a comminuted intra-articular distal humerus fracture in an older, low-demand patient whose articular surface cannot be reconstructed stably enough to move early.
McKee's multicentre randomised trial allocated 42 patients aged over 65 with displaced intra-articular distal humerus fractures to fixation or semiconstrained total elbow arthroplasty.
Mayo Elbow Performance Scores favoured arthroplasty at 3 months (83 versus 65), 6 months (86 versus 68), 12 months (88 versus 72) and 2 years (86 versus 73), all statistically significant.
However, DASH scores favoured arthroplasty only in the short term, with no significant difference at 12 months (32 versus 47) or at 2 years (34 versus 38), which is the nuance that marks a strong candidate.
Five of the 21 patients randomised to fixation could not be fixed and were converted to arthroplasty during surgery, so the trial is also evidence about how often a plan changes on the table.
Long-term follow-up of the same cohort by Dehghan and colleagues found that of 25 arthroplasties, only one needed early revision, and 15 patients died with a well-functioning implant in place.
What do the BOA Standards require for a distal humerus fracture?
Two BOA Standards frame a distal humerus fracture: the December 2021 standard on peripheral nerve injury and the May 2019 standard on the older or frail orthopaedic trauma patient.
The peripheral nerve injury BOAST states that formal advice should be sought within 24 hours for any peripheral nerve injury where operative management of the associated fracture is not indicated.
It also requires advice before surgery when a fracture with a nerve injury is to be fixed, and immediately when a new deficit appears after surgery and loosening measures have failed.
When a nerve is exposed during fixation of a distal humerus fracture, the same standard requires the operation note to describe the nerve's relationship to the implant.
The May 2019 frailty BOAST asks for a frailty pathway with geriatric assessment starting within 72 hours of injury, and for surgery within 36 hours of admission, in line with hip fracture care.
That standard also requires surgery to allow full weight-bearing for daily activities and a physiotherapy review on the first postoperative day, which matters for an older patient who needs the arm to stand up.
What are the complications of a distal humerus fracture?
The complications of a distal humerus fracture are stiffness, heterotopic ossification, ulnar neuropathy, nonunion of the fracture or of the olecranon osteotomy, implant prominence and infection.
Ulnar neuropathy is the one with a number attached: 19.3% across Shearin's pooled series, and no protection from routine anterior transposition in either that analysis or Li's review.
Reoperation after a distal humerus fracture was 4 of 15 after fixation and 3 of 25 after arthroplasty in McKee's trial, a difference that did not reach significance.
After total elbow arthroplasty the patient carries a lifelong lifting restriction, and the late risks are loosening, periprosthetic fracture and infection, which is why it is reserved for low-demand elbows.
What is the interviewer listening for on distal humerus fractures?
The interviewer is listening for a documented ulnar nerve examination before and after everything you do to a distal humerus fracture, and for a named plan rather than a vague one.
They want the decision framed around the patient: bone quality, articular comminution, functional demand and frailty, not the radiograph on its own.
A strong candidate quotes McKee both ways: arthroplasty won on the Mayo score at every point to two years, but DASH had converged by 12 months and reoperation rates did not differ significantly.
What are the common mistakes with distal humerus fractures?
The commonest mistake with a distal humerus fracture is a neurovascular examination recorded as "NVI", which the BOAST says is not detailed enough to compare with later examinations.
The second is offering arthroplasty to a young or high-demand patient with a distal humerus fracture, when McKee's trial recruited only patients aged over 65.
Others are skipping the CT before planning an articular reconstruction, promising anatomical fixation of comminution you have not seen, and forgetting that this patient may need both arms to transfer.
How this comes up at the ST3 interview
A distal humerus fracture arrives at the ST3 T&O clinical station as a radiograph and a one-line stem: an 82-year-old who fell onto her elbow, with a comminuted intra-articular fracture.
The follow-ups are predictable: how you examine and record the ulnar nerve, what imaging you want, would you fix it or replace it, and what evidence supports that.
orthointerview's question bank turns this into station-form questions with model answers and AI-marked spoken practice, across 782 questions and 100 scenarios, so the McKee numbers are said aloud before the day.