What is forearm mal-union?
The forearm is made up of a set of two bones, the Ulna and the Radius, and muscles and tendons that surround the bones. After trauma to these bones they begin to heal. Sometimes their position may develop an angulation or rotation that is outside the normal parameters which can restrict functionality and/or appearance of the forearm. Mal-union healed in an unacceptable position, affecting function and/or rotation is an unfortunate complication of some forearm fractures in children.
Signs and Symptoms
Signs of a forearm mal-union often include wrist pain, decreased rotational motion, and unsatisfactory cosmetic appearance. Forearm mal-unions can result in functional impairment, leaving you without the ability to use your forearm the way you want to. Symptoms of a forearm mal-union usually develop after a specific trauma. Below you can see that this patient’s left forearm is unable to rotate like the right forearm. Figure 2 below shows the right forearm in a normal supination position; the forearm rotated such that the palms are facing upward. Notice that the left arm is unable to rotate like the right forearm. Figure 3 shows the right forearm pronating; forearm rotated such that palms face the floor. The left forearm is unable to rotate into this position like the right. This lack of left forearm rotation can be very limiting for the patient by severely restricting the type of activities or work that they are able to perform.
These are a forearm motion, not a wrist motion.
Surgical approach is often necessary with a forearm mal-union. See Publication:
Alaskan Three-Dimensional Osteotomy: Surgical Correction for long Bone Malunions.
The Journal of Hand Surgery, Volume 33A, May- June 2008.
Diagnosis of a Forearm Mal-union
The diagnosis is based on signs, symptoms and physical exam, as well as further information that can be gained from x-rays and/or computed topology (CT) scan. The diagnosis will begin with a thorough history, paying close attention to the mechanisms of injury. Physical examination will follow and will demonstrate limitations in forearm supination and pronation, as well as obvious bowing deformity compared to the unaffected side. Most often, x-rays are taken of the forearm and then changes in the radius or ulna bones are critically analyzed to see if they may contribute to pain and symptoms. The Dr may request that you also under go a CT scan to understand fully the multiple planes of deformity. Using all this information the surgeon will determine the best course for the patient to regain movement with their forearm.
Many forearm mal-unions may require an osteotomy, the surgical procedure where the mal-aligned bone is repositioned for better functional use. It is also referred to as a 3 dimensional osteotomy because it involves not only repositioning the bone from side to side, but also rotating it. This is a surgical procedure where the surgeon will reposition the bone and then insert a plate to secure the bone together as it heals. This is referred to as – anatomic open reduction with 3-dimensional osteotomy, followed by internal fixation. Dr. McNamara has developed 3 D Osteotomy tools to assist him with this procedure in treating forearm mal-unions. (See Figure 4) Properly applied surgical techniques can improve/restore function to the forearm and improve cosmetic appearance, thereby enhancing the patient’s quality of life.
The Alaskan 3-Dimensional (3-D) Osteotomy is a simple, reproducible procedure for effective correction of angulation in two planes, length and rotation deformities of mal-united long bones. (Figure 5)
Following Surgery, the forearm is immobilized to allow for healing. The patient is placed in a long arm splint for 10 days to two weeks or until the sutures are removed. Then patient is placed in a long arm cast for another month or so. Total time of protection depends on degree of correction, health of patient, age, and activity level. After that the patient will be placed into a well-padded clamshell brace to regain rotational movement with the forearm. Often protection is required for a minimum of 8-12 weeks. The patient will go for slow progressive rotational movement, supination and pronation as the fracture demonstrates healing on the x-rays.
The Alaskan 3-D Osteotomy corrects angulation in two planes, rotation and length deformities of long bones. This technique helped patients with mid-shaft long bone mal-unions return to active lifestyles by alleviating joint pain, improving forearm rotation and restoring more normal cosmetic appearance.
Without the Alaskan 3-D Osteotomy, the radius mal-union patient above could not have enjoyed “7.6 seconds on Prime Rib”!