Distal Humerus Fractures - Trauma

Introduction

Overview
- distal humerus fractures are traumatic injuries that include
  - supracondylar fractures
  - single column (condyle) fractures
  - bicolumn fractures
  - coronal shear fractures
Epidemiology
- incidence
  - accounts for 0.5-7% of all fractures
  - accounts for 30% of elbow fractures
- demographics
  - most common in young males and older females
- location
  - distal intercondylar fractures are the most common fracture pattern
Pathophysiology
- mechanism
  - low energy falls in elderly
  - high energy impact in younger population
- pathoanatomy
  - elbow position affects fracture type
    - elbow flexed < 90°
      - axial load leads to transcolumnar fracture
      - direct posterior blow leads to olecranon fracture with or without distal humerus involvement
    - elbow flexed > 90°
      - may lead to intercondylar fracture
Associated injuries
- elbow dislocation
- terrible triad injury
- floating elbow
- Volkmann contracture
  - results from missed forearm compartment syndrome
Prognosis
- majority of patients regain 75% of elbow motion and strength
- goal is to restore elbow ROM 30-130° of flexion
- unsatisfactory outcomes in up to 25%
  - treatment of these fractures is complex due to
    - low fracture line of one or both columns
    - metaphyseal fragmentation of one or both columns
    - articular comminution
    - poor bone quality

Anatomy

Osteology
- elbow is a hinged joint
- trochlea
  - articulates with sigmoid notch
  - allows for flexion and extension
- capitellum
  - articulates with proximal radius
  - allows for forearm rotation
Muscles
- common flexors (originate from medial epicondyle)
  - pronator teres
  - flexor carpi radialis
  - palmaris longus
  - FDS
  - FCU
- common extensors (originate from lateral epicondyle)
  - anconeus
  - ECRL
  - ECRB
  - extensor digitorum comminus
  - EDM
  - ECU
Ligaments
- medial collateral ligament
  - anterior bundle originates from distal medial epicondyle
  - inserts on sublime tubercle
  - primary restraint to valgus stress at the elbow from 30-120°
  - tight in pronation
- lateral collateral ligament
  - originates from distal lateral epicondyle
  - inserts on crista supinatorus
  - stabilizer against posterolateral rotational instability
  - tight in supination
Nerves
- ulnar nerve
  - resides in the cubital tunnel in a subcutaneous position below the medial condyle
- radial nerve
  - resides in the spiral groove 15cm proximal to distal humeral articular surface
  - runs between brachioradialis and brachialis proximal to elbow
  - divides into PIN and superficial radial nerve at the level of the radial head

Classification

Can be classified as
- supracondylar fractures
- distal single column fractures
  - subclassified using Milch classification system (see table)
  - lateral condyle more common than medial
- distal bicolumnar fractures
  - classified using Jupiter classification system (see table)
  - 5 major articular fragments have been identified
    - capitellum/lateral trochlea
    - lateral epicondyle
    - posterolateral epicondyle
    - posterior trochlea
    - medial trochlea/epicondyle

AO/OTA Classification of Distal Humerus Fractures
Type A	Extraarticular (supracondylar fracture),80% are extension type; epicondyle
Type B	Intraarticular-Single column (partial articular-isolated condylar, coronal shear, epicondyle with articular extension)
Type C	Intraarticular-Both columns fractured and no portion of the joint contiguous with the shaft (complete articular)
Each type further divided by degree and location of fracture comminution

Milch Classification of Single Column Condyle Fractures
Milch Type I	Lateral trochlear ridge intact
Milch Type II	Fracture through lateral trochlear ridge

Jupiter Classification of Two-Column Distal Humerus Fractures
High-T	Transverse fx proximal to or at upper olecranon fossa
Low-T	Transverse fx just proximal to trochlea (common)
Y	Oblique fx line through both columns with distal vertical fx line
H	Trochlea is a free fragment (risk of AVN)
Medial lambda	Proximal fx line exists medially
Lateral lambda	Proximal fx line exists laterally
Multiplane T	T type with additional fracture in coronal plane

Presentation

Symptoms
- elbow pain and swelling
Physical exam
- gross instability often present
  - avoid ROM due to risk of neurovascular damage
- neurovascular exam
  - check function of radial, ulnar, and median nerves
  - check distal pulses
    - brachial artery may be injured
    - if pulse decreased, obtain noninvasive vascular studies and consult vascular surgery if abnormal
- monitor carefully for forearm compartment syndrome

Imaging

Radiographs
- recommended views
  - AP
  - lateral
- additional views
  - obtain wrist radiographs if elbow injury present or distal tenderness on exam
  - oblique and traction radiographs may assist with surgical planning
    - specifically used to evaluate if there is continuity of the trochlear fragment with the medial epicondylar fragment, this can influence hardware choice
CT
- often obtained for surgical planning
- especially helpful when shear fractures of the capitellum and trochlea are suspected
MRI
- usually not indicated in acute injury

Treatment

Nonoperative
- cast immobilization
  - indications
    - nondisplaced Milch Type I fractures
Operative
- closed reduction and percutaneous pinning (CRPP)
  - indications
    - displaced Mich Type I fractures
- ORIF
  - indications
    - supracondylar fractures
    - intercondylar / bicolumnar fractures
    - Milch Type II fractures
- total elbow arthroplasty
  - indications
    - distal bicolumnar fractures in elderly patients

Techniques

Cast Immobilization
- technique
  - immobilize in supination for lateral condyle fractures
  - immobilize in pronation for medial condyle fractures
ORIF
- approach
  - posterior superficial approach
- exposures
  - triceps-splitting (Campbell)
    - technique
      - split triceps tendon in midline down to olecranon
  - triceps-sparing (paratricipital, Alonso-Llames, medial and lateral windows)
    - indications
      - extra-articular fractures
      - fractures with a simple articular split
    - technique
      - elevate triceps from the humerus using medial and lateral windows
      - can be converted to olecranon osteotomy if needed
  - olecranon osteotomy
    - indications
      - complex intra-articular fractures
      - fractures with a coronal splint
    - contraindications
      - total elbow arthroplasty is planned/may be required
    - technique
      - perform chevron (apex distal) osteotomy
      - fixation of osteotomy performed using a combination of screws, K wires, tension band or plate
    - complications
      - AIN nerve injury
        
        check ability to flex thumb interphalangeal joint in recovery
  - triceps-reflecting (Bryan-Morrey)
    - technique
      - reflect triceps tendon, forearm fascia, and periosteum off the olecranon from medial to lateral
      - repair through transosseous drill holes
      - immobilize to protect triceps repair for 4-6 weeks postoperatively
  - triceps-reflecting anconeous pedicle (O'Driscoll)
    - technique
      - elevate anconeous subperiosteally from proximal ulna
  - lateral muscles interval
    - technique
      - elevate the ECRB and part of the ECRL off of the supracondylar ridge
- fixation
  - perform provisional reduction with k-wires
    - if metaphyseal injury is not comminuted, reducing one column to the metaphysis first may be beneficial
  - perform fixation of articular fragments with countersunk/headless screws
    - consider using positional screws when reducing trochlea to avoid narrowing it with compression
  - perform fixation of condyles and epitrochlear ridge
    - fix the lateral epicondyle using a tension band wire or plate
    - fix the articular segment to the shaft using two plates in orthogonal planes
      - new literature supports parallel plates
    - if the ulnar nerve contacts medial hardware during flexion/extension, can perform an ulnar nerve transposition
      - literature does not support decreased ulnar nerve symptoms with transposition
- postoperative
  - splint elbow in 70° of flexion
  - remove splint at 48 hours post-operatively and initiate ROM exercises
    - if osteotomy performed
      - active and active-assisted flexion and extension for 6 weeks
      - no active extension against gravity or resistance
      - no restrictions to rotation
    - if osteotomy not performed
      - active motion against gravity without restrictions
      - no restrictions to rotation
  - start gentle strengthening program at 6 weeks and full strengthening program at 3 months
Total Elbow Arthroplasty
- indications
  - communited articular fractures in osteoporotic bone
  - inflammatory conditions (e.g. RA)
- complications specific to this treatment
  - activity restrictions (e.g. can not lift more than 5 pounds)
  - implant loosening
  - polyethylene wear
  - periprosthetic fracture

Complications

Elbow stiffness
- most common
Heterotopic ossification
- seen in 8%
- routine prophylaxis is not warranted due to increased rate of nonunion in patients treated with indomethacin
Nonunion
- low incidence
- avoid excessive soft-tissue stripping
Malunion
- avoided by proper surgical technique
  - cubitus valgus (lateral column fractures)
  - cubitus varus (medial column fractures)
AIN injury
- can be seen with olecranon osteotomy
Ulnar nerve injury
DJD