Forearm Anatomy

The morphological feature of the ulna is that the upper end is thick and gradually becomes thinner.
Lateral view: There is a physiological arc between the proximal 3/4 and the distal 1/4.

There are two physiological curvatures of the radius, one is from lateral plane, the radius protrudes to the radial side; the other is from the frontal plane and there is a physiological curvature to the back.

Forearm Function

Reduction of Anatomic Curvature
Radial bow, not less than 5-10°

Ulnar bow, in the range of 0-5°

The ulnar medullary cavity is slightly round, and on the axis of the medullary cavity extending from the proximal 1/4 of the ulna to the distal end, the narrowest part is about 1cm far from the midpoint of this line, and the diameter is 4-5mm.

Epidemiology

Ulna and radius fractures accounted for 18.28% of the total number.
More men than women, more on the left than on the right.
Proximal and diaphyseal segments accounted for 12.37% and 13.04% of the total number of ulnar fractures.

Ⅱ. Classification of Ulna and Radius Fractures

Operative Indication（AO）

Displaced fracture of both bones of forearm

Angulation is greater than 10°, rotation displacement is greater than 10°

Displaced fracture of a single bone of forearm

Special type: Monteggia fracture, Galeazzi fracture, Essex-Lopresti injury

All open fractures

Ⅲ. Surgical Treatment Plans and Deficiencies

Intramedullary Nail VS. Plate

Ozkaya et al. 's study in 2009 showed that:：
Intramedullary nailing fixation is more advantageous in terms of time to union and blood loss.
Exposure of the surgeon and the surgical team to radiation beam is a disadvantage of the intramedullary nail fixation.
There were no significant difference in mean operation time, postoperative complications, functional healing, and patient satisfaction.

Insufficient of Plate Internal Fixation

Radial nerve injury (0.5-2.7%).
Nonunion caused by fracture as high as 5-12%, large surgical incision, and deep infection as high as 4%.
Prone to secondary fractures after the plate is removed, the rate is reported as high as 11%-20%.
Large surgical incision affect the appearance.

Insufficiency of External Fixation

Pin infection risk

Nerve damage

High incidence of nonunion

Unattractive and not convenient

Advantages of Intramedullary Nail Fixation

Minimally invasive implantation, small incision

Anatomical design, excellent fit

Easy to operate

Less complications

Lee et al. 2008 reported the application of intramedullary nailing. A total of thirty-eight interlocking intramedullary nails were inserted into the forearms of twenty-seven adults.The average time to fracture union was fourteen weeks.There was one nonunion of an open comminuted fracture ofthe middle third of the ulna. There were no deep infections or radioulnar synostoses. Twenty-two patients (81%) had an excellent result; three (11%), a good result; and two (7%), an acceptable result. The excellent and good results were obtained in 92.6%.

Selection of Forearm Intramedullary Nail

Elastic Intramedullary Nail VS. Interlocking Intramedullary Nail

1. Interlocking Intramedullary Nail has anti-rotation effect.
2. Anatomical design, no need for preoperative bending.
3. Various lengths for more choices, no need to cut, to avoid soft tissue irritation caused by sharp distal ends
4.Traditional entry point of elastic nail: lateral distal radius (disadvantages: may damage the superficial branch of radial nerve) New entry point：Lister tubercle

Kirschner Wire VS. Interlocking Intramedullary Nail
1. Kirschner wire is often used to treat children's forearm fractures. It is minimally invasive and low-cost. However, because the end is exposed outside the bone, it can irritate the soft tissues and is prone to infection, and the Kirschner wire is easy to loosen.
2. The diameter of Kirschner wires is small, it is difficult to match the medullary cavity of large diameter, and the stability is poor.