Introduction:

Supracondylar fractures are the third most common fractures in children but at the same time the most commonly operated ones. Closed reduction and percutaneous pinning (CRPP) has become the gold standard of treatment of the supracondylar fractures in children preventing complications of deformities and compartment syndrome.
Indications:
1. All grade 3: CRPP is the gold standard of treatment. Even in the patients with vascular injury, open fractures and nerve injury it is the initial line of treatment.
2. Grade 2 when reduced because reduction process breaks the posterior cortex and converts type 2 into unstable type 3.
3. Grade 1 with medial comminution as they have tendenct to produce varus deformity if not fixed.

Princinciples:

The most common complication of SCSH is cubitus varus, and the most dreaded complication is Volkmann ischemic contracture. The first can be prevented by an accurate reduction. However, without fixation, it is necessary to maintain the elbow at 110 degrees or more of flexion to maintain the reduction. With the subsequent swelling that occurs around the elbow, this position restricts venous drainage from the forearm, resulting in increased swelling and compartment syndrome. If the elbow is extended to 90 degrees, there is a likelihood that the reduction will be lost. An accurate reduction and the use of percutaneous skeletal fixation to permit the elbow to extend to 90 degrees while maintaining reduction thus prevents both the complications allowing optimum treatment of these fractures in children.

Biomechanics Of Reduction

To understand the importance of accurate reduction, it is necessary to understand peculiar of the humerus at the fracture site and the mechanics of how the deformity occurs.
The supracondylar fracture of the humerus occurs through the thinnest portion of the bone: the area of the coronoid fossa anteriorly and the coracoid fossa posteriorly. A cross-section of this area looks like a dum bell like structure with thick medial and lateral bone masses and thin central area in between. Therefore, without the rotational correction, the medial and lateral columns will not be opposed and naturally and the reduction will be unstable. As a result, the distal fragment may tilt and angulate, producing deformity. This rotational deformity can be seen clinically in cases of angular deformity. However, because of the large range of rotation in the shoulder joint, this rotational deformity is not apparent cosmetically or functionally.

OT Arrangement

It must be emphasized that this is a radiographic technique. Proper positioning of the patient, the image intensifier, and the assistant greatly simplifies the procedure.

The recording tube of the image intensifier becomes the operating table. The patient is shifted to the side of the table so that the shoulder is at the edge. A tourniquet can be applied in case an open reduction is necessary. The arm is draped. A sheet is kept under the arm to fascilitate the use of drill for K wire fixation.

The Technique of Reduction

It is important to remember that this reduction does not require strength, and in fact, if the reduction is not done gently, the remaining periosteal hinge will be torn, creating an unstable situation and a much more difficult reduction.
The reduction of a supracondylar fracture is not difficult if each of the steps in the reduction described by Rang are performed in the proper sequence.
Step 1 Traction: The first step in the reduction is the application of traction to the arm, which is flexed about 15 degrees to reduce the distal fragment in line with the proximal fragment. In most extension type supracondylar fractures, there is an intact periosteum posteriorly that aids in the reduction by providing a stable fulcrum.

Step 2 Correction of medio-lateral displacement: The second step is the correction of the medial or lateral displacement. This can be seen from the preoperative radiograph or the image intensifier during the reduction. It must be performed before the surface of the two bony fragments are brought into contact because after they are reduced, it is impossible to slide one over the other.
Step 3 Correction of Rotataion: The third step is to correct the rotation. This must be done again before the two fragments are brought into apposition. If the rotation is not correct, the fragments must be disengaged before another attempt at correction of the rotation. In most cases, the distal fragment requires external rotation.
Step 4 Correction of posterior displacement and locking of reduction: With rotation and medial and lateral displacement corrected, the posterior displacement can be corrected. While the assistant supports the arm, the surgeon places one thumb behind the medial condyle and the other behind the lateral condyle. Pushing forward, the surgeon corrects the posterior displacement. The elbow is then flexed, which reduces the fracture. The final step of reduction is to pronate (if medially displaced) or supinate (if laterally displaced) the arm to tighten the remaining medial or lateral periosteal hinge.

THE TECHNIQUE OF PINNING

The assistant holds the elbow in acute flexion, which maintains the reduction.
The arm is examined with the image intensifier to determine the adequacy of the reduction. Four views should be examined by internally and externally rotating the arm back and forth at each view to ensure that the proper aspect of the reduction is seen. The anteroposterior view is the least helpful because the overlying forearm obscures the bony detail of the humerus. The arm is held acutely flexed while the lateral view is examined. If the diameters of the two fragments at the fracture site are different, malrotation is present. If the proper angle between the condyles and the shaft has not been restored, hyperextension and lack of full flexion of the elbow results. Next, the lateral and medial condyles are examined by oblique views. The internal oblique view demonstrates the lateral condyle, and the external oblique view demonstrates the medial condyle. If the lateral view shows that the rotation is incompletely reduced, these oblique views demonstrate which condyle is not completely reduced and whether more internal or external rotation is needed.

When the reduction is achieved, the percutaneous pins are inserted. Usually, 1.25 Kirschner wires are adequate for the fixation.

The options for pin placement are
1. Two lateral pins
2. Three lateral pins
3. One medial and one lateral pin
One medial and one lateral pin provide the optimal degree of stability but carries a small risk of ulnar nerve injury. We pass two or three lateral pins and do external rotation test to stability of ulnar nerve. Following this is the fixation is stable medial pin is not passed. However if there is medial comminution or if the fixation is unstable additional medial pin is passed taking care not to injure the ulnar nerve

Lateral K wire Insertion
Although it is more easier to rotate the arm externally than internally and pass medial pin forst the position of hyperflexion subluxates the ulnar nerve anteriorly making it vulnerable to injury. Hence the lateral pin is passed first.
The assistant continues to hold the elbow acutely flexed while rotating the arm with the lateral condyle facing up. The lateral condyle is palpated, and the Kirschner wire on the drill is pushed through the skin and into the bone. The image intensifier can be used to determine whether the location is correct and to aid in directing the wire so that it does not pass too far anteriorly or posteriorly and miss the proximal fragment. The wire should engage the opposite cortex. The direction of wire is from anterior to posterior around 15 degrees to match the lower end humerus profile.

Medial K wire insertion
The arm, still held in acute flexion, is rotated until the medial condyle faces up. The thumb of the left hand (right-handed surgeon) finds the medial epicondyle. If swelling makes this difficult, the elbow can be extended slightly. The thumb should roll off of the inferior edge of the epicondyle into the ulnar grove and remain there holding the nerve in the grove. The Kirschner wire is started just at the tip of the thumb and is directed with image intensifier guidance, as in the previous example. If the surgeon is uncertain about the location of the ulnar nerve, a small incision over the ulnar groove can be made and the ulnar nerve located and held out of the way with a small curved hemostat.
Both pins should engage the opposite cortex. Ideally, they pass up the medial and lateral columns of bone and do not cross at the fracture site. It is important to ascertain that the pins are in the distal fragment because, in the surgeon’s desire to avoid the ulnar nerve, the pin may start too far proximally and miss the distal fragment. These views from the image intensifier are recorded as the final films because they will be far superior to any films taken through the cast, and no further change in the fracture can occur if the pins are placed properly. Finally, the arm can be extended fully and examined clinically for any deformity.
Four View Xray Examination
After placement of both pins, the arm is again examined in all four views with the image intensifier to confirm the reduction and the placement of the pins. The internal rotation oblique view demonstrates the lateral condyle, and the external oblique view demonstrates the medial condyle. If the fracture is not anatomically reduced, these views show which condyle is incompletely reduced.
If all is satisfactory, the pins are cut and bent over, leaving them outside the skin to facilitate removal in the office.

Post op management

The arm is held in 90 degrees of elbow flexion and supination. Above elbow slab is given in 100 degrees of flexion. Pins are removed at 4 weeks after confirming union and elbow mobilization is started