Fig. F6D: Callus removal results in redundant periosteum. Resect the excess tissue and suture the remainder snugly over the repair site.
The tips of the screws should not invade the space between the major and minor metacarpal bones.
Fig. X6D: a) The fracture occured just above the area of synostosis. b) Screws proximal to the synostosis should not engage the third metacarpal bone. c) Cosmetic healing occurred and the plate remained in place for 8 years, after which the patient was lost to follow-up.
6.4 Postoperative considerations
Intolerance to cold, with resultant pain and lameness, may necessitate implant removal.
A pressure bandage is applied postoperatively to aid in the prevention of seroma formation. The administration of perioperative antibiotics is continued for 24 hours. The horse is stall rested for 10 days until the skin sutures can be removed. Elastic bandaging is continued for 3 weeks. Controlled exercise is begun 1 month postoperatively, while exercise at will at pasture is discouraged for a full 12 weeks. Training is resumed at 4–6 months postoperatively, depending on soundness and radiographic healing. Typically, these fractures heal cosmetically, without the recurrence of the preoperative exostosis.
6.4.1 Complications
The only complication encountered with this surgery has been the need for implant removal due to intolerance to cold (Fig. S6C, Fig. X6E) Although this has been reported anecdotally for other fixations, the problem seems greater in this area of little skin and hair cover, with a relatively large surface area of metal lying subcutaneously. Owners should be made aware of this, since it alters the time frame for a return to training. It is recommended that strenuous exercise be postponed until the screw holes have filled in with bone, which can take up to 90 days.
Fig. X6E: At 8 months postoperatively (a), the horse was back in work but showed occasional pain, especially in cold weather. The plate was removed (b), and training successfully resumed 60 days later (c).
Fig. S6C: The tangential view and the straight AP view show good cosmetic healing 3 months postoperatively in this open jumper.
6.5 Results
The results of this treatment have been uniformly successful, even when used in older fractures (Fig. X6F). Infected fractures also respond positively to fixation, since the stability conferred is rigid (Fig. S6D), expediting the resolution of infection and enhancing healing. Antibiosis is begun preoperatively based upon appropriate culture and sensitivity testing.
Fig. X6F: This series of films shows healing at 3 days (b), 3 months (c), 5 months(d), and 2 years (e). The horse raced for 5 years with the plate in place before being lost to follow-up.
Fig. S6D: Thoroughly debride infected fractures, and remove any callus that has formed prior to the application of the plate.
6.6 References
1. Jann HW, Fackelman GE, Pratt G (1986) Strain patterns in the second metacarpal bone and their surgical significance. Vet Surg; 15:124.
2. Harrison LJ, May SA, Edwards GB (1991) Surgical treatment of open splint bone fractures in 26 horses. Vet Rec; 28:606–610.
3. Baxter GM, Doran RE, Allen D (1992) Complete excision of a fractured fourth metatarsal bone in eight horses. Vet Surg; 21:273–278.
4. Botz R (1993) Total amputation of the fourth metatarsal bone after fracturation in a horse. Prakt Tierarzt; 74:918.
5. Bowman KF, Fackelman GE (1980) Comminuted fractures in the horse. Comp Cont Educ Pract Vet; 2:98.
6. Müller ME, Allgöwer M, Schneider R, et al. (1977) Fractures of the lateral malleolus. In: Müller ME, Allgöwer M, Schneider R, et al., editors. Manual of Osteosynthesis. Heidelberg:Springer Verlag, 267.
6.6.1 Online references
See online references on the PEOS internet home page for this chapter: http://www.aopublishing.org/PEOS/06.htm
Gustave E. Fackelman
7.2 Preoperative considerations
7.4 Surgical procedure
7.5 Postoperative care
7.6 Results
7.7 References
7.7.1 Online references
7.1 Description
Common anamnesis: repeated bouts of lameness with pain and swelling in the fetlock region, pain on passive flexion of the MC joint and point pain in the distal metaphyseal region.
Repeated radiographs and scintigraphy may be needed to make a definitive diagnosis.
Fractures of the distal metacarpal and metatarsal condyles were among the earliest to be repaired by internal fixation [1]. Their relationships to the distal articular surface and to the long axis of the bone are relatively simple and technical problems are few. In general, these fractures are racehorse injuries, are more common in Thoroughbreds than in Standardbreds, and usually affect the lateral condyle (Fig. X7A). Fractures of the medial condyle may appear similar radiographically (Fig. X7B), but when examined more closely, they are far more extensive and require more aggressive treatment [2]. As with a number of other exercise induced fractures, condylar fractures appear to occur in stages. A common anamnesis includes: signs of repeated bouts of lameness associated with pain and swelling in the fetlock region; passive flexion of the metacarpophalangeal joint appearing painful; and, possible occasional point pain detectable in the distal metaphyseal region. These 2–3 day periods of lameness alternate with periods of apparent athletic soundness. Only after repeated radiographs are taken at different intervals and from various angles does the bony defect become visible [3]. There is scintigraphic evidence that there may be some predisposing (vascular) disorder of the distal metacarpus (Fig. X7C) that precedes actual bony failure [4], as has been observed in humans [5, 6]. The gradual nature of the failure may be connected with prevailing loading characteristics, as has been demonstrated in experimental animals [7]. In describing the repair procedure below, the metacarpus will be used as an example. Mention will be made