1. Distal humerus― intraarticular fractures and complications
Published: September 2013
Author: Fabian M Stuby, DE
Reviewed: 2019
Reviewer: Ashraf Moharram
AO Trauma Advanced Principles Course

2. Learning objectives
Understand the surgical anatomy of the distal humerus
List indications for surgical treatment and outline the different surgical approaches
Formulate surgical tactics for:
Reducing the different fracture patterns
Fixing the articular surface
Plating the two columns
Predict expected outcomes and identify potential complications
List key outcome publications
Teaching points:
Reinforce the absolute stability dictum for the articular fracture, and the option for relative stability for the metaphyseal fracture component.

3. Anatomy—anterior Triangular structure provides strength
Lateral column
Medial epicondyle
Trochlea
Lateral epicondyle
Medial column
Coronoid fossa
Triangular structure provides strength
Bony surface at the center is thin = tie-rod
The strength of the distal humerus is based around two strong bony columns—lateral and medial. The two columns are connected at the level of the joint and the strength of fixation depends on accurately reconstructing this triangular shape. The coronoid fossa is extremely thin and of no mechanical strength.
When dealing with the distal humerus, one needs to think of it as a medial column, lateral column, and a central keystone piece—the trochlea, while remaining aware of the coronoid fossa, olecranon fossa, medial and lateral epicondyle.

4. Anatomy—functional anatomy
Trochlea is center point
Hinged joint with single
axis of rotation
(trochlear axis)
Distal humeral triangle
The distal humerus is essentially a triangle. With two main columns holding the articular part. The elbow is a pure hinge joint—“gingulus“. The center of the joint in the trochlea is just medial to the long axis of the humeral shaft.
The axis of rotation is normally 5° of valgus.
5°valgus

5. Anatomy
First we have to know something about the anatomy. Here is the articulation of the radial head, and this is the trochlea.

6. Anatomy
If you look sideways in lateral view, you are able to see another angle that you have to keep in mind while operating, the distal humerus angles forward 30°.

7. Evaluation Physical examination Neurological status:
Soft-tissue envelope
Vascular status
Radial and ulnar pulses
Neurological status:
Radial nerves
Ulnar nerve
Median nerves (rarely injured)
Evaluation of these injuries includes soft-tissue examination and vascular status (ie, radial and ulnar pulses). Evaluation of neurological status involving the radial, ulnar, and median nerves.

8. X-ray evaluation—AP and lateral
X-ray evaluation includes AP and lateral x-rays.

9. Radiological evaluation
Anterioposterior
Lateral
Traction view
CT scan

10. Value of CT scans? CT scans are helpful in case of:
Intraarticular fractures
Severe osteoporosis
Preexisting deformities
Comminution
CT scans are very useful with severe comminution. They can help to plan the operation.
If the bone stock is good and there is no comminution, a regular x-ray might be sufficient.

11. AO/OTA Classification—type A
Humerus, distal segment (13)
Type A—extraarticular
A1—avulsion fracture
A2—simple fracture
A3—multifragmentary fracture
If you keep in mind what we just learned about anatomy, the AO/OTA classification of fractures is very logical.
Type A fractures are extraarticular injuries, which can be treated through a single incision on the side of the injury, and stabilized directly.
AO/OTA Classification, 13-A is a nonarticular fracture.

12. B2 AO/OTA Classification—type B Humerus, distal segment (13)
Type B—partial articular
B1—lateral condyle fracture
B2—medial condyle fracture
B3—frontal plane fracture, trochlea/capitulum
Type B fractures are partial articular fractures. Depending on the involvement of the articular surface, one might need an exposure of it.
AO/OTA Classification, 13-B is a partial articular fracture.

13. AO/OTA Classification—type C
Humerus, distal segment (13)
Type C—complete articular
C1—articular simple; metaphyseal simple
C2—articular simple; metaphyseal multifragmentary
C3—articular multifragmentary
Type C fractures are complete articular fractures. There is no intact connection of the joint and diaphysis. Those are very difficult injuries to treat.
AO/OTA classification, 13-C is a complete articular fracture.

14. Treatment principles What do we want:
Anatomical reduction of the articular surfaces
Stable internal fixation of the articular surface
Restoration of articular axial alignment
Stable fixation of the articular segment to the metaphysis and diaphysis
Early range of motion (ROM) of the elbow
Our goals are:
Anatomical articular reduction
Stabilization of articular surfaces
Restoration of axial alignment (remember the anatomical angles)
Stable fixation
Early range of motion

15. Other treatment options
Total elbow arthroplasty
Comminuted intraarticular fracture in the elderly
Promotes immediate ROM
Usually limited by poor remaining bone stock
“Bag of bones” technique = nonoperative treatment
Cast or brace
Indicated for completely nondisplaced, stable fractures
We do have some other potential options, like total elbow arthroplasty, which we only use for very elderly and very comminuted fractures.
“Bag of bones” is rarely indicated because of the pain that is involved and because newer techniques of both arthroplasty and internal fixation are available (bag of bones technique is nonoperative treatment with early motion).
Cast or brace is also only very rarely used because most of the fractures are unstable and dislocated.

16. Decision making Questions to ask:
One or two column fracture (type B or C)?
Intraarticular surface disturbed?
Reduction and fixation possible?
Severity of soft-tissue damage?
So to boil it down to the real questions:
Do we have a one or two column fracture?
How intense is the injury of the articular surface?
Is it possible to reduce and fix this fracture?
Do the soft tissues allow an operative treatment without high risk of infection?
Is the articular surface involved and can it be fixed?

17. Positioning of the patient
Lateral
Prone
Once we have decided to perform an osteosynthesis, we have to plan the operation properly.
How do we position the patient? It is desirable to be able to have flexion of at least 100° on the table. Therefore, we prefer the prone position. Though lateral is also possible.

18. Approach
The approach is a straight incicision on the dorsal elbow, allowing exposure of the distal humerus and proximal ulna.

19. Identification of the ulnar nerve
First thing to do is to identify the ulnar nerve and mobilization. After that, you tie a string around the nerve, which will stay there for the rest of the operation.
Now you perform the osteotomy according to your preoperative plan.

20. Osteotomy of the olecranon
AP view
Lateral view
There are other possibilities for accessing the fracture other than the osteotomy of the olecranon.
However, we believe that neither triceps splitting or extraarticular osteotomy are adequate for intraarticular fractures.
Therefore we prefer the intraarticular osteotomy as shown here. But be careful: the last part of the osteotomy should be done with a chisel.

21. Locating osteotomy
To locate the exact position of the osteotomy, it is helpful to use lateral view x-rays and a drill. The hole is going to be the tip of your V of the osteotomy.

22. Intraoperative view
After the osteotomy is finished and you have opened the articular capsule, you will have a nice (or not so nice) overview of the injury.

23. Reduction
After identifying the joint surface parts, you have to try anatomical reduction of these pieces forming a fixed joint block as shown here.
Sometimes this takes a lot of time and patience.

24. Temporary fixation
Once the joint block is properly reduced, you will have to reduce this block to the diaphyseal part as shown here for example with reduction forceps and afterwards temporary fixation with K-wires.

25. Final fixation
Last step of the humeral fracture treatment is the fixation with plates. We do prefer two plates, if possible at a 90° angle. However, it is also possible to use them at a 180° angle.
Also, locking plates are recommended because of superior stability. However, these implants are not always available, so you will have to fabricate your own plates out of what you have, for example 3.5 reconstruction plates or LCDC plates.

26. Osteotomy fixation
Refixation of the olecranon is either done with a screw (be aware that you will have to drill and tap before you perform the osteotomy to provide a perfect result) or with two K-wires and tension band.
Of course you could also use a plate, however, tension bands are a lot cheaper than plates.

27. Locking concepts
As for the availability of implants, we are lucky and do have access to these improved implant designs, which provide better fixation especially in elderly osteoporotic bone.

28. Postoperative result
If everything mentioned before is taken into account, you will achieve reduction with a good postoperative result. But of course this is not always the case.
There are several complications to be mentioned:
Pain related to hardware can be up to 70% of cases
Infection rate up to 6% in closed fractures and higher in open fractures
Up to 8% reoperation rate

29. Complications Malunion
Apart from these common surgical complications we are confronted with some other severe complications in distal humeral fractures.

30. Complications
Secondary
dislocation

31. Complications Associated fractures
Associated (iatrogenic) fractures, in this case due to external fixation and Schanz screws.

32. Complications Incomplete reduction
Incomplete reduction, especially on the flexion side opposite to our approach. The case above is not very severe because the articular surface is not affected.

33. Case example
Patient with polytrauma
II° open distal humeral fracture

34. Initial treatment
External fixator with attention to Schanz screw positioning
Soft-tissue debridement with jet lavage

35. Postoperative result 3 days postoperative 8 weeks postoperative
The plates should be different lengths, so that they do not produce stress at the same area on the humeral shaft.

36. Postoperative range of motion
Pronation/supination: 90–0–90°
Extension/flexion: 0–15–120°

37. Take-home messages Essentials:
Knowledge of the anatomy of the distal humerus
Proper preoperative planning
Adequate exposure for articular reduction
Knowledge of reduction and fixation methods
Treatment principles as for all intraarticular injuries
As a summary, you should remember:
You have to know the anatomy of the distal humerus to treat these fractures
Proper preoperative planning is mandatory
Adequate exposure for articular reduction is necessary
You need to know reduction methods and how to use them
Follow the principles for all articular fractures
Anatomical reduction and stable reconstruction with early motion give good results

38. Take-home messages Still a difficult fracture Short distal fragments
Poor bone stock
High rate of complications (loss of fixation)
Lower complication rate with:
Proper technique and application of principles
New implants with locked screws
Total elbow arthroplasty is an alternative in patients with osteopenia
It is still a difficult fracture. Very short distal segments with poor bone quality are a major problem. These have a high rate of fixation failure due to the small amount of distal bone and the bone quality.
Complications are generally those of poor technique and poor application of principles.
New implants with a better design and locking head screws are an improvement.
Total elbow arthroplasty is an alternative in patients with osteoporotic bone.