Distal Humerus Fractures - Trauma

Introduction

Consists of
- supracondylar fractures
- single column (condyle) fractures
- bicolumn fractures
- coronal shear fractures
Epidemiology
- incidence
  - distal intercondylar fractures are the most common fracture pattern
- demographics
  - most common in young males and older females
Pathophysiology
- mechanism
  - low energy falls in elderly
  - high energy impact in younger population
- pathoanatomy
  - elbow position affects fracture type
    - elbow flexed < 90 degrees
      - axial load leads to transcolumnar fracture
      - direct posterior blow leads to olecranon fracture with or without distal humerus involvement
    - elbow flexed > 90 degrees
      - may lead to intercondylar fracture
Associated injuries
- elbow dislocation
- terrible triad injury
- floating elbow
- Volkmann contracture
  - result of a missed forearm compartment syndrome
Prognosis
- majority of patients regain 75% of elbow motion and strength
- goal is to restore elbow ROM 30-130 degrees of flexion
- unsatisfactory outcomes in up to 25%
  - treatment of these fractures is complex due to:
    - low fx 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 to 120 deg
  - tight in pronation
- lateral collateral ligament
  - originates from distal lateral epicondyle
  - inserts on crista supinatorus
  - stabilizer against posterolateral rotational instability
  - taut in supination
Nerves
- ulnar nerve
  - resides in cubital tunnel in a subcutaneous position below the medial condyle
- radial nerve
  - resides in spiral groove 15cm proximal to distal humeral articular surface
  - between brachioradialis and brachialis proximal to elbow
  - divides into PIN and superficial radial nerve at level of 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 nerve
  - check distal pulses
    - brachial artery may be injured
    - if pulse decreased, obtain noninvasive vascular studies; consult vascular surgery if abnormal
- monitor carefully for forearm compartment syndrome

Imaging

Radiographs
- recommended views
  - obtain AP and lateral of humerus and elbow
  - include entire length of humerus and forearm
- additional views
  - obtain wrist radiographs if elbow injury present or distal tenderness on exam
  - oblique radiographs may assist in surgical planning
  - traction radiographs may assist in surgical planning
    - specifically evaluate if there is continuity of the trochlear fragment to 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
- 3D CT scan improves the intraobserver and interobserver reliability of several classification systems
MRI
- usually not indicated in acute injury

Treatment

Nonoperative
- cast immobilization
  - indications
    - nondisplaced Milch Type I fractures
  - technique
    - immobilize in supination for lateral condyle fractures
    - immobilize in pronation for medial condyle fractures
Operative
- closed reduction and percutaneous pinning
  - indications
    - displaced Mich Type I fractures
- open reduction internal fixation
  - indications
    - supracondylar fractures
    - intercondylar / bicolumnar fractures
    - Milch Type II fractures
- total elbow arthroplasty
  - indications
    - distal bicolumnar fractures in elderly patients

Techniques

Open Reduction Internal Fixation
- positioning
  - lateral decubitus position
    - on foam mattress with radiolucent arm board
  - prone position
    - useful in patients with spine injuries or contralateral extremity fractures
  - supine positioning
    - can be used in a polytrauma situation or with contraindications to other positioning
  - obtain test imaging before prepping and draping
  - prep entire arm from shoulder to hand
- approach
  - articular surface exposure
    - olecranon osteotomy 57%
    - triceps-reflecting 46%
    - triceps-splitting 35%
  - posterior superficial approach
    - raise full thickness medial and lateral soft tissue flaps
    - elevate deep fascia to identify ulnar and radial nerves
  - triceps splitting (Campbell)
    - split triceps tendon in midline down to olecranon
  - tricep sparing (known as paratricipital, Alonso-Llames, medial and lateral windows)
    - indications
      - extra articular fractures or fractures with simple articular split)
    - can be converted to olecranon osteotomy if needed
    - medial side
      - identify ulnar nerve and dissect it 15cm proximal to elbow joint proximally, and distally to first motor branch to FCU
      - elevate triceps from posterior aspect of humerus on medial side and free it from medial intermuscular septum
      - posterior band of MCL is elevated and posterior joint capsule entered to visualize trochlea
    - lateral side
      - identify radial nerve proper proximally if fracture is distal
        
        if fracture is distal and does not require long plates, proper radial nerve does not need to be exposed
      - elevate remainder of tricep from posterior aspect of humerus
      - anconeus may be divided or dissected on lateral side to improve exposure
  - olecranon osteotomy
    - indications
      - complex intra articular fragments and/or presence of coronal splint)
    - contraindications
      - total elbow arthroplasty is planned/may be required
    - technique
      - identify bare area of sigmoid notch medially and laterally
      - pre-drill (for 6.5mm screw) or plate prior to making bone cut
      - pass sponge through ulnohumeral joint to protect articular surface while making cut
      - fluoroscopy is used to confirm location of osteotomy
      - shallow chevron (apex distal) is cut down to subchondral bone (95% cut)
      - finish cut (remaining 5%) with osteotome
      - peel olecranon and triceps proximally and wrap with saline soaked sponge
      - fixation
        
        screw, K wires and tension band or plate
        
        clamp osteotomy from medial and lateral side with large pointed reduction clamps
        
        insert 6.5, 7.0 or 7.3mm screw (or plate) in previously drilled hole
        
        apply tension band
        
        still preferable for posterior trochlea fx and medial epicondyle fx
    - complications
      - AIN nerve injury
        
        check ability to flex thumb interphalangeal joint in recovery
  - triceps reflecting (Bryan-Morrey)
    - reflect triceps tendon, forearm fascia and periosteum from medial to lateral off olecranon
    - repair through transosseous drill holes
    - immobilize to protect triceps repair for 4-6wk postop
  - triceps-reflecting anconeous pedicle (O'Driscoll)
    - elevate anconeous subperiosteally from proximal ulna
    - medial exposure is Bryan-Morrey triceps reflecting approach
  - lateral muscles interval
    - is an alternative to visualize the articular
    - elevate ECRB and part of ECRL of supracondylar ridge
    - usually able to work anterior to and sacrifice LCL
    - if fx of lateral column, utilize and mobilize
    - sublux joint to assist in articular visualization
- fixation principles (O'Driscoll)
  - fixation in the distal fragment must be maximized
  - all fixation in distal fragments should contribute to stability between the distal fragments and the shaft.
- fixation objectives (O'Driscoll)
  - every screw in the distal fragments should pass through a plate
  - engage a fragment on the opposite side that is also fixed to a plate
  - as many screws as possible should be placed in the distal fragments
  - each screw should be as long as possible
  - each screw should engage as many articular fragments as possible
  - the screws in the distal fragments should lock together by interdigitation, creating a fixed-angle structure
    - this creates the architecural equivalent of an arch, which gives the most biomechanical stability
  - plates should be applied such that compression is achieved at the supracondylar level for both columns
  - the plates must be strong enough and stiff enough to resist breaking or bending before union occurs at the supracondylar level.
- fixation
  - countersunk / headless screw to fix articular fragments 1st after provisional reduction with k-wires
    - if metaphyseal injury is not comminuted, reducing one column to the metaphysis first may be beneficial
    - consider using positional screws when reducing trochlea to avoid narrowing it with compression
  - then address condyles and epitrochlear ridge
    - lateral epicondyle may be fix with tension band wire or plate
  - two plates in orthogonal planes used to fix articular segment to shaft
    - place 3.5-mm LCDC plate or one of equivalent strength on lateral side
    - place 2.7-mm or 3.5-mm LCDC plate on medial side
    - interdigitate screws if possible to increase strength
  - new literature supports parallel plates
  - if ulnar nerve contacts medial hardware during flexion/extension, can transpose however literature does not support decreased ulnar n. symptoms with transposition
  - postoperative
    - place in splint with elbow in approx 70 degrees of flexion
    - remove splint at 48 hours post-operatively, initiate ROM exercises
      - if osteotomy performed patient may do active and active assisted flexion and extension for 6 weeks; no active extension against gravity or resistance
      - if not osteotomy, permitted to do 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

Complications

Elbow stiffness
- most common
Heterotopic ossification
- reported rate of 8%
- routine prophylaxis is not warranted
  - 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 fxs)
  - cubitus varus (medial column fxs)
DJD
Ulnar nerve injury
AIN Injury
- can be seen with olecranon osteotomy