Intra-Articular Fracture Of The Medial Condyle

The line of fracture passes obliquely through the condyle, entering just above its tip and emerging on the articular surface of the trochlea either in the groove separating the two portions of the trochlea or the groove between the trochlea and capitellum. As already explained (page 282), the integrity of the joint and the line of the arm depend on the trochlea and not on the capitellum, therefore the farther over toward the capitellum the line of fracture goes the more likely is there to be lateral mobility (Fig. 312).

The fragment may be pushed up; this carries the ulna up with it while the radius is prevented from following by the capitellum. Therefore the forearm bends inward, making a lateral deformity. The carrying angle (page 282) becomes obliterated and what is known as gunstock deformity or cubitus varus is produced. It is mainly to the researches of Dr. O. H. Allis that we are indebted for our knowledge of the mechanism of this deformity. The attachment of the flexor muscles does not keep the fragment from rising. The deformity is difficult to detect when the elbow is flexed. The condyles and olecranon and shaft of the humerus may all be in the same straight line and still the medial (internal) condyle be higher than normal. If the injury is treated with a right-angled splint the radius and ulna remain in their proper positions but the ulna and medial condyle may both be higher than normal. If this is the case, then, when the forearm is extended, instead of it making an angle of 10 degrees outwardly with the line of the humerus, it may incline 10 degrees or even 20 degrees inwardly: thus it may deviate as much as 30 degrees from the normal direction. To guard against this deformity Allis advised treating the injury with the arm in full extension. Any tendency to lateral deformity will then be at once evident and can be corrected by additional lateral support. Certain it is that no serious fracture of the elbow ought to be treated without frequent examinations of the arm in full or almost complete extension being made from time to time, so as to be sure this deformity is not becoming established.

The treatment of fractures involving the joint by placing the elbow in a position of complete flexion has been strongly advocated, although it has not entirely superseded other methods.

Fig. 312.   Fracture of internal condyle and trochlea, causing gun stock deformity (cubitus varus). From a photograph of a preparation in the Mutter Museum of the College of Physicians.

Fig. 312. - Fracture of internal condyle and trochlea, causing gun-stock deformity (cubitus varus). From a photograph of a preparation in the Mutter Museum of the College of Physicians.

Intercondylar Or T Fracture

When both condyles are detached there is produced what is known as a T fracture. In this injury both condyles are detached from each other and from the shaft of the humerus. The line of fracture may vary. Sometimes there is a transverse fracture above the condyles with a second line passing longitudinally into the joint like the letter T. In other cases the lines may be like the letter V or Y (Fig. 313).

In all these cases the mobility is very marked and the limb can be bent at the elbow in any direction. The diagnosis is to be made by grasping the shaft of the humerus with one hand and moving each condyle separately with the other. Having determined that each is detached from the humerus, then one condyle is grasped in each hand and they are moved on one another, thus establishing • the fact of a fracture between them.

In treatment the same care must be exercised to detect the occurrence of gunstock deformity as has already been advised in fractures of the medial condyle. In these fractures the fragments are frequently rotated on one another, and disability and deformity so often result that in some cases it is advisable to fix the fragments in place by some operative means.