The sequence of repair is dependent on the ease with which the fracture can be reduced. In fractures which are easily reduced and maintained reduction forceps may be adequate to maintain reduction for plate fixation. In fractures which are difficult to reduce it can be advantageous to place a transphyseal screw and wire construct to aid in fracture reduction. Once the fracture is aligned and held in temporary reduction fixation proceeds with placement of a plate on the caudal aspect of the olecranon and ulna. The plate screws should engage the caudal cortex of the radius distally. Once the plate is in place, the reduction forceps and the transphyseal screw and wire construct can be removed and the second plate can be applied to the lateral aspect of the proximal radius.
Intraoperative imaging is in this procedure to assist in implant positioning and aid in screw placement.
The fracture is brought into reduction and held in place with pointed reduction forceps if possible.
In cases which are difficult to bring into reduction it may be necessary to initially apply a transphyseal screw and wire construct laterally.
Plate selection and preparation
Usually, an 8-12 hole narrow plate is appropriate for application to the ulna, depending on the size of the foal. DCP, LCP or LC-DCP have been used successfully. A soft aluminum template is used to determine the appropriate contour for plate application to the caudal aspect of the ulna, starting proximally at, or near, the olecranon physis and extending distally to span the fracture. For the radius, an 8-10 hole narrow plate is usually sufficient. When selecting the plate lengths, make sure that they do not end at the same level distally.
Application of the first plate
The plate, in this case a LC-DCP, is applied to the caudal aspect of the ulna with 2 screws in the proximal and 2 screws in the distal fragment to maintain reduction of the fracture while the plate is applied to the lateral aspect of the radius.
Application of the second plate
The second plate is contoured to the lateral surface of the radius with the help of an aluminum template. The plate is applied to the lateral aspect of the radius. If a LCP is used, the stacked combi hole should be positioned over the epiphysis. Additionally it is important to place all cortex screws prior to the locking head screws. The cortex screws that are in the plate just distal to the physis should be placed in lag fashion into the metaphyseal fragment to increase stability and provide interfragmentary compression, providing the fragment is of sufficient size.
Care must be taken to ensure accurate placement of the epiphyseal screw to avoid inadvertent penetration of the joint. In an DCP or LC-DCP the angle of drilling can be adjusted using radiographic or fluoroscopic control to achieve this objective. However, if an LCP is available, the epiphyseal screw should be a locking head screw, and the plate must be contoured appropriately to ensure the screw does not enter the articulation. Intraoperative imaging is required during placement of these implants to ensure appropriate screw position.
At least two additional locking head screws are inserted distal to the fracture line.
Insertion of the remaining screws
Once the plate is applied to the radius, the remaining screws in the ulnar plate are inserted and engage the radius between the screws in the radial plate. If deemed necessary, a cortex screw can be inserted in lag fashion across the ulnar fracture line engaging also the caudal cortex of the radius.
Care must be taken to avoid joint penetration of the screws adjacent to the trochlear notch.
Note: the principle for fractures of the olecranon in foals younger than 7 months of age to avoid transfixing the ulna to the radius because this would lead to incongruity of the elbow joint does not hold true in these fractures. Fractures of the proximal radial physis are supplemented with an additional plate in the olecranon and ulna. Because the radial physis has been injured and a plate is placed across the proximal radial physis, growth of the proximal radius is obviated and therefore elbow congruency is maintained.
It is advisable to take radiographs prior to closure of the incision. Any implant changes necessary can at that time be easily executed without causing any complications.
Antibiotic impregnated polymethylmethacrylate beads are placed along the plates prior to closure. The surgical incisions are closed using routine technique. The caudal incision is frequently covered first with a stent bandage because regular bandage frequently displace distally during getting up and laying down. A light bandage is then applied covering the proximal radius and ulna until the skin staples or stiches are removed.
Some surgeons prefer to use suction drains, but the author does not routinely use them.
6. Overview of rehabilitation
The foal is kept in stall rest for a minimum of 60 days. The first 30 days hand-grazing only is advised, followed by 30 days of hand-walking.
Follow up radiographs are taken at 60 days. If healing appears to be progressing without complications the foal is gradually transitioned to free paddock exercise.
The implants are left in place unless complications develop.