Case Report Transfixation cast technique for arthrodesis of the distal interphalangeal joint of horses J. L. Easter 1 ; J. Schumacher 2 ; J. P. Watkins 3 1 Performance Equine Associates, Whitesboro, Texas, USA; 2 Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee, USA; 3 Department of Large Animal Medicine & Surgery, College of Veterinary Medicine, Texas A&M University, College Station, Texas, USA Keywords Distal interphalangeal joint, arthrodesis, osteoarthritis, infection, horse Summary Surgical arthrodesis of the distal interphal- angeal (DIP) joint by transfixation casting was used to salvage a three-year-old filly and a yearling filly that were chronically lame be- cause of infection of the DIP joint for breed- ing. Unlike previously described techniques for arthrodesis of the DIP joint, the technique used did not require insertion of implants across the joint, which may have contributed to the successful outcome. Correspondence to: Dr. J. Lane Easter Performance Equine Associates 15257 U.S. Hwy. 377 Whitesboro, Texas 76273 United States Phone: +1 903 564 7443 Fax: +1 903 564 3704 E-mail: lane.easter@pea-tx.com Vet Comp Orthop Traumatol 2011; 24: 62–67 doi:10.3415/VCOT-09-05-0061 Received: May 29, 2009 Accepted: June 28, 2010 Pre-published online: November 19, 2010 Introduction A common indication for arthrodesis of the distal interphalangeal (DIP) joint is ir- reversible damage to that joint. Causes may include instability, infection, advanced os- teoarthritis, articular fracture, osteochon- drosis, and traumatic injury to periarticu- lar ligaments and soft tissue structures of the joint. The aim of arthrodesis is to relieve pain and improve function of the limb to salvage a horse that has value for breeding or as a pet (1–4). The purpose of this report is to describe a technique for arthrodesis of the DIP joint that does not use transarticular implants, making it particularly useful for arthrode- sis of a chronically infected DIP joint. This report describes the clinical findings, treat- ment, and outcome of two horses that underwent arthrodesis of the DIP joint using this technique. Surgical technique of arthrodesis of the distal interphalangeal joint Horses were anesthetised and positioned in lateral recumbency with the affected limb up. The superficial layer of horn was re- moved from the hoof wall and sole with a grinder, the sole and the most distal cen- timetre of the wall were covered with a latex glove, and the distal portion of the limb was aseptically prepared for surgery. Two Steinmann pins a (4.8 mm diameter Steinmann pins for horse 1, and 6.2 mm, positive-profile, threaded, large animal transfixation pins for horse 2) were placed in the distal aspect of the third metacarpal bone in standard fashion for application of a transfixation cast (5–7). Radiopaque markers were placed on the hoof wall to tar- get the centre of the DIP joint. A window in the hoof wall, centred over the lateral aspect of the joint, was created using a 19 mm bone trephine b . The laminae were excised with a scalpel, and the hoof wall and laminae were elevated en bloc with an osteotome to ex- pose the DIP joint. A 3.2 mm hole was dril- led through the joint, from lateral to medial, using radiographic control to ensure that the drill bit was centred across the joint. This hole was sequentially enlarged using in- creasingly larger bits (4.5 mm, 5.5 mm, and 12.7 mm drills) (Fig. 1). A small amount of soft bone was removed from the margin of the 12.7 mm hole using a curette, but no effort was made to remove cartilage from the articular surfaces of the distal and middle phalanges or navicular bone. The hole was packed with alternating layers of poly- methylmethacrylate c (PMMA) beads con- taining tobramycin d (9.6 g of tobramycin/40 g of PMMA) and cancellous bone harvested simultaneously from the wing of the ilium by a second surgical team. Approximately 20, crudely fashioned beads, approximately 3 mm in diameter, were placed. The defect in the hoof wall was packed with cancellous bone to within 4 to 5 mm of the surface of the hoof wall, and 40 g PMMA e containing 500 mg gentamicin, was placed over the de- fect in the hoof, flush with the hoof wall. The PMMA patch was covered with a sterile dressing, and a fiberglass, transfix- ation cast that extended from the sole of the hoof to the proximal end of the metacarpus was applied to the limb. Case reports Horse 1 An eight-month-old, American Quarter Horse filly was referred because of lame- a Imex Veterinary, Inc., Longview TX, USA b Galt trephine: Miltex Instrument Company, Inc., Lake Success, NY, USA. c Surgical Simplex P Bone Cement: Howmedica Os- teonics, Mahwah, NJ, USA. d Nebcin: Eli Lilly and Company, Indianapolis, IN, USA. e Technovit, Jorgenson Labs, Inc., Loveland, CO, USA. Vet Comp Orthop Traumatol 1/2011 62 © Schattauer 2011 For personal or educational use only. No other uses without permission. All rights reserved. Downloaded from www.vcot-online.com on 2018-03-31 | ID: 1000333563 | IP: 54.70.40.11