Orthopedics - Oleksa A.P. 2006

Congenital upper limb malformations
Congenital forearm anomalies
Congenital radioulnar synostosis

Congenital synostosis of the forearm bones is a rare condition, accounting for 0.61% of orthopedic deformities (Kolyaditsky V.G., 1964). It is four times more common bilaterally (Nikiforova E.K., 1968) and is occasionally hereditary. Synostosis results from a disruption or arrest of embryonic development in the early stages, occurring more frequently in male fetuses (Reinberg S.O., 1964).

In congenital synostosis, the Diagnosis can be established within the first months of a child's life. Typically, restricted or absent rotational Movements of the forearm are observed. At the same time, radiographic signs of bone fusion are not yet visible and appear only over time. This fusion is located in the proximal part of the bones (Fig. 122) and is usually small in size, connecting the bones just beneath the radial HEAD; however, it can occasionally be extensive, spanning up to one-third of their length. In cases of extensive synostosis, the head of the radius typically fuses with the ulna.

The bones fuse in a pronated position, which is why this condition is also referred to as "congenital pronation." Because supination of the forearm and hand is impossible, the child compensates by performing adaptive movements in the Shoulder and Elbow joints to turn the palm ventrally. Flexion and extension of the forearm at the elbow are unrestricted and free.

Follow-up radiographs show that both forearm bones are normally developed and possess correct anatomical shapes. A bony connecting bridge is visible in their upper third, confirming the clinical diagnosis. In adults, this bridge exhibits a trabecular Structure, with the cortical layers transitioning smoothly from one bone to the other in the diaphyseal region. The radial head is occasionally deformed (Reinberg S.A., 1964).

Congenital synostosis of the forearm bones may be associated with other Congenital Malformations, particularly of the fingers and hands.

Treatment. Conservative treatment is ineffective at any age. Therefore, all hopes rely on surgical intervention, although surgical outcomes do not always satisfy the physician or the patient due to The high frequency of synostosis (bony fusion) recurrence.

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Fig. 122. Congenital radioulnar synostosis

The surgery is performed under general anesthesia. The synostosis is exposed via a posterior approach along the PROJECTION OF THE interosseous space. Using an osteotome, the bony bridge is isolated alongside the cortical layer of both forearm bones and excised. Meticulous hemostasis is essential in all cases. The most critical steps of the Procedure are interpositioning between the bones (using bovine testicular tunica albuginea, preserved fascia, etc.) and wound drainage for 1–2 days. It is important to initiate forearm supination exercises by the 4th to 5th postoperative day and maintain a prolonged regimen of active and passive mobilization.

Abakarov A.A. and Razumovsky A.V. (1986) perform resection of the radius distal to the synostosis, removing a 3–4 cm fragment along with its periosteum, and replace it with an allograft of the radial head, connecting it to the peripheral fragment. This is followed by osteotomy of the ulnar neck with rotation in the desired direction to optimize supination and pronation Functions.