The wound is first properly debrided and cleaned of all potential contamination with a separate sterile debridement set. The fracture is subsequently anatomically reduced and repaired with two plates spanning the entire bone and applied at 90° relative to each other (left). In small ponies, some foals and selective cases of adult horses only one plate may be selected (right). It is very important to insert some interfragmentary screws to assure the not only the plate(s) bridge the fracture. Care must be taken in foals to avoid bridging the distal physis of the bone.
The use of LCPs and the addition of bone grafts and/or antibioticimpregnated PMMA beads is encouraged.
2. Initial management
The wound is first debrided and any visible contamination removed- Flushing of the wound should be performed from the opposite side of the limb facilitating exit of the flushing solution through the already present skin wound. The debridement set is subsequently packed away.
Regional intravenous limb perfusion was initiated during wound debridement.
Large reducible fragments are attached to the major fragments with 3.5 mm cortex screws in lag fashion. Ideally the screws are inserted in a location not occupied later by one of the two plates. Small fragments void of any periosteal attachement are discarded. If needed the screws heads can be countersunk such that they are completely buried within the cortex of the bone, allowing placement of a plate directly over it.
The first plate is applied over reattached fragments. Incorporation of the distal epiphysis and physis is avoided.
The second plate is placed at 90° relative to the first one applying routine technique. In the presence of a bone defect, the second plate should be placed over it after filling the defect with cancellous bone graft harvested from the tuber coxae.
The longitudinal incision splitting the common digital flexor tendon is closed using a simple continuous suture pattern with a monofilament synthetic suture.
Skin closure is routine, but may be difficult. Frequently tension relieving sutures are necessary to close the skin completely. The original skin wound is closed last. If the wound is small and not located over an implant it may be left open to allow drainage.
The limb is covered by a sterile bandage, which is changed usually at 4-day intervals unless shorter intervals need to be selected because of drainage develops from the wounds.
The patient is kept in a box stall for one month with some hand grazing after two weeks. The bandage is maintained for 2-3 weeks and changes at 4-day intervals. At the end of the first month the patient is allowed some exercise in a small paddock for one additional month.
Follow up radiographs are taken 2 months postoperatively. The radiographs show some bone lysis and the original would opened up again and is draining.
Follow up care
The patient is re-anesthetize, all screws checked for tightness and the screws located over the enlarged defect removed. A massive cancellous bone graft is applied and antibiotic impregnated PMMA beads added over the defect.
Immediate postoperative radiographs are taken to document the present status. Monitoring of fracture healing is continued including repeated intravenous regional limb perfusion. And systemic antimicrobial therapy.
Draining continued but with time decreased in the amount. The patient started to apply more weight on the fractured limb. Radiographically progressive bone healing was observed. At 5 month after the initial fracture fixation a solid, smooth callus bridged the original bone defect.
The dorsal plate was subsequently removed and the the surgery site flushed and carefully curetted. The animal was kept in a stall with the limb bandaged and gradually the exercise load could be increased. Some minor draining persisted.
At 8 months bone had sufficiently healed to allow removal of the second plate. The persistent minimal draining ceased within a week after removal of the second plate. After removal of the skin sutures ten days postoperatively, the animal was turned out in a pasture.
More information about implant removal can be found here.