Distal ulna fracture (DUF) is a common concomitant injury with distal radius fracture (DRF), and in most cases, it can be managed non-surgically without affecting functional outcomes. However, if there is instability in the distal radioulnar joint (DRUJ) or if there is triangular fibrocartilage complex (TFCC) injury, surgical fixation may be necessary. In such cases, plate fixation is a feasible and successful option.
Classification of Distal Ulna Fractures (AO): a Radial head, b Olecranon tip, c Ulnar styloid, d Ulnar head, e Ulnar neck, f Ulnar shaft distal. Q1 Ulnar styloid fracture, Q2 Isolated ulnar neck fracture, Q3 Comminuted ulnar neck fracture, Q4 Ulnar head fracture, Q5 Ulnar head-neck combined fracture, Q6 Ulnar shaft distal fracture. Blue dashed line junction of ulnar metaphysis and epiphysis, blue solid line joint area, red line fracture line.
This article will focus on the surgical treatment of distal ulna fractures, excluding ulnar styloid fractures. It will primarily discuss the steps and considerations of plate fixation.
1. Positioning
The patient is placed in a supine position with the arm abducted and positioned on the operating table. The wrist is internally rotated and slightly elevated to create a better approach angle.
2. Opening
Utilize the radial approach. Palpate the styloid process of the radius (far distal line) before making a straight, longitudinal incision (dashed line) between the extensor and flexor carpi radialis muscles, approximately 5 centimeters in length. Caution should be taken to protect the posterior branch of the radial nerve.
3. Expose
The dorsal branch of the ulnar nerve must be dissected. It runs along the dorsal edge of the ulnar side of the wrist flexor muscle, approximately 5 cm from the proximal end of the pisiform bone, traveling subcutaneously. Therefore, before encountering the fascia, further divide the subcutaneous tissue with spreading scissors. The area where the dorsal branch of the ulnar nerve is frequently encountered is indicated by the blue dashed line circle.
4. Reset
A fracture can be reduced using reduction forceps. Depending on the type of fracture, Kirschner wires can temporarily fix the distal fragments to the distal radius. To ensure anatomical reduction, perform fluoroscopic examination. Evaluate the distal radioulnar joint.
5. Steel Plate Placement Position
(1) The placement of the steel plate must take into consideration the prevention of impact and rotation restrictions on the ulnar side wrist extensor tendons. Identify a safe zone and utilize a steel plate of sufficient size, covering a small area including the ulnar border and a palmar portion of the ulnar border. The black dashed line coincides with the ulnar border and the styloid process of the ulna. The blue area represents the secure region where the plate is fixed. If the black dashed line is considered as 0°, the safe zone extends approximately from 0 to 30° palmarly. b A schematic diagram illustrates the safe zone of the ulnar aspect of the distal radius in palmar, ulnar, and dorsal views. FCU denotes the flexor carpi ulnaris muscle on the ulnar side of the wrist. The blue hatched lines indicate the safe zone.
(2) First, secure the steel plate near the proximal end using a 1.8mm drill bit and 2.4mm cortical screw. Then, make slight adjustments to the distal end.
(3) After securing the proximal end, use a 2.4mm variable-angle locking screw to fix the distal fracture segment. Perform a perspective check to assess ulnar height, ensuring anatomical reduction during fixation.
(4) a. After confirming with fluoroscopy, secure the steel plate completely. Ensure that the screws do not protrude into the distal radioulnar joint.
b. Conduct fluoroscopic imaging to assess the position of the fully fixed steel plate.
(5) Next, perform a comprehensive motion examination of the wrist through fluoroscopic imaging to assess any potential restrictions. The surgeon evaluates potential impingements during the examination. In case of limitations, the positioning of the plate must be reconsidered.
(6) Preoperative, intraoperative, and postoperative images of patients with distal radius fracture combined with ulnar fracture.
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Post time: Nov-20-2023