Supracondylar fracture of Humerus

Supracondylar fracture occurs most commonly in children between the age 5 and 15 years

It is caused by a fall on the out stretched hand

Basic anatomy :

The elbow joint is a simple hinge joint allowing movement in only one plane

It is made up of three seperate joints namely

• Proximal radioulnar joint
• Humeroradial joint
• Humeroulnar joint

The distal end of  the humerus is flattened farming two process namely the 

• lateral epicondyle
• medial epicondyle

                                   form the anatomical landmarks

Medial to lateral condyle lies the capitulum

Lateral to the medial condyle lies the trochlea

The bony points 

There are three bony points around the elbow

• the medial condyle
• the lateral condyle
• the tip of olecranon

• They help in determining the normal anatomy of the joint.
• These reference  points also helpful in determining any deformity of the elbow joint 
• Normally in an elbow flexed at 90°, the three bony points make an isosceles triangle (any two sides are in equal length)
• In extended position of elbow, these three bony prominence make a straight line

The Carrying angle 

When the elbow is extended and supinated the long axis of the arm and that of forearm form an angle which is called Carrying angle

• It disappears in flexion of elbow 
• Normal angle 
• Male : 11°     Female : 14°

Ossification around the elbow

• One should be able to differentiate between the normal ossification centre and the fractured fragments

• without this knowledge one may think normal ossification centre as a fractured fragments

TYPES :

1.Extension type : 95-98%

In this type the distal fragments is displaced backwards

2.Flexion type :

In this rare type the distal fragments is displaced forward

CLINICAL FEAUTURES :

• The child complains of severe pain in the elbow and holds it in the flexed position
• The swelling is tense filling up the hollow around the elbow 
• Palpitation will elicit tenderness in the distal end of the humerus

• In this injury one should always feel the radial pulse to see if there is any pressure in the  brachial artery
• A weaker radial pulse compared to the opposite side needs emergency attention to save the circulation of forearm

DIFFERENTIAL DIAGNOSIS :

Posterior dislocation of elbow :

In supracondylar fracture the normal triangle relationship is not disturbed in case of posterior dislocation the relationship is grossly disturbed and the three points lies in a line

DIAGNOSIS :

1.Physical exam :

• gross deformity
• swelling
• ecchymosis {bruises} in antecubital fossa
• limited elbow motion

2.Nerve exam

evaluate for 

Anterior interosseous nerve {ACN} neuroproxia

can't make OK sign

Median Nerve injury :

loss of sensation over the volvar index finger

Radial nerve neuroproxia :

inability to extend wrist, MCP joints,thumb joint

3.Vascular exam 

• assess vascular perfusion 

well perfused- warm and pink

• poorly perfused

cold and pale

4.Imaging 

Recommanded views : AP and lateral view of elbow

Findings :

• Positive posterior fat pad sign
• Displacement of the anterior humeral line

anterior humeral line should intersect the middle third of the capitulum in children ≥ 5 years old and touches the capitulum in children <5 years
Capitulum moves posteriorly to this reference line in extension type and anterior in flexion type

• Alteration in Baumann angle

Baumann line is created by drawing a line parallel to the longitudinal axis of the humeral shaft and a line along the lateral condylar physis as viewed on AP

Normal 70-75° but best judge by comparing it with the contralateral side

RADIOLOGICAL CLASSIFICATION :

Based on X ray, Garland has classified supracondylar  fracture as following

Type 1 : Undisplaced

Type 2 : Partially displaced but posterior cortex intact

Type 3 : Complete displacement in both anterior posterior and lateral views

TREATMENT :

1.Crack with displacement :

only a posterior plaster slab with good padding for about 2-3 weeks

2.Displaced fracture :

• need reduction under general anaesthesia with traction , countertraction and local pressure
• a posterior slab is applied with good padding

3.If fracture fragments are unstable :

open reduction and internal fixation with K wire is done

4.Injury to the Neurovascular bundle :

A fracture complicated by any injury to the neurovascular bundle leading to neurovascular compromise requires exploration and decompression with appropriate vascular and plastic surgery inputs

COMPICATION :

Early : 

• Injury to the median nerve {anterior interosseous nerve}
• Injury to the brachial artery {volkmann ischemia}
• Pin migration 
• Infection
• Nerve injury

order of occurrence of nerve injury :

1^st  Anterior interosseous nerve (branch of median nerve )

2^nd  Median nerve –posterolateral displacement

3^rd Radial nerve -  posteromedial displacement

4^th ulnar nerve – commonly injured iatrogenically by pinning

Late :

1.Cubital varus deformity :

• Most common complication
• Malunion of the fracture leading to the cubitus varus  deformity called Gunstock deformity
• Corrected by supracondylar osteotomy of humerus

2.myositis occificans

3.elbow stiffness

4.Cubital valgus (rare)

5.Volkmann ischemic contracture