Osteochondral fragments are infrequently encountered in the PIP joint in horses, and to our knowledge, only a few cases have been described in the literature.1–3 Previously reported locations for such fragments include the dorsoproximal margin of the middle phalanx,3 the palmar midsagittal aspect of the middle phalanx,1 and the palmaromedial aspect of the middle phalanx.2 Palmar fragments may represent partial avulsion fractures of the fibrous connective tissue attachments involving the PIP joint,4 whereas dorsal fragments have been suggested to be developmental in origin.3
To our knowledge, osteochondral fragments involving the dorsomedial aspect of the PIP joint in young horses have not been described previously. The purpose of the study reported here was to determine clinical and diagnostic imaging findings in young horses with osteochondral fragments involving the dorsomedial aspect of the PIP joint.
Modransky PD, Grant BD, Rantanen NW, et al. Surgical treatment of a palmar midsagittal fracture of the proximal second phalanx in a horse. Vet Surg 1982;4:129–131.
Welch RD, Watkins JP. Osteochondral fracture of the proximal palmar middle phalanx in a Thoroughbred. Equine Vet J 1991;23:67–69.
Schneider RK, Ragle CA, Carter BG, et al. Arthroscopic removal of osteochondral fragments from the proximal interphalangeal joint of the pelvic limb in three horses. J Am Vet Med Assoc 1994;205:79–82.
Watkins JP. Fractures of the middle phalanx. In:Nixon AJ, ed.Equine fracture repair. Philadelphia: WB Saunders Co, 1996;129–145.
Nixon AJ. Phalanges and the metacarpophalangeal and metatarsophalangeal joints. In:Auer JA, Stick JA, ed.Equine surgery. 3rd ed.St Louis: Saunders Elsevier, 2006;1217–1237.
Trotter GW, McIlwraith CW, Norrdin RW, et al. Degenerative joint disease with osteochondrosis of the proximal interphalangeal joint in young horses. J Am Vet Med Assoc 1982;180:1312–1318.
Pool RR. Difficulties in definition of equine osteochondrosis; differentiation of developmental and aquired lesions. Equine Vet J 1993;suppl 16:5–12.
Carlson CS, Cullins LD, Meuten DJ. Osteochondrosis of the articular-epiphyseal cartilage complex in young horses: evidence for a defect in cartilage canal blood supply. Vet Pathol 1995;32:641–647.
Grøndahl AM, Dolvik NI. Heritability estimations of osteochondrosis in the tibiotarsal joint and of bony fragments in the palmar/plantar portion of the metacarpo- and metatarsophalangeal joints of horses. J Am Vet Med Assoc 1993;203:101–104.
Schougaard H, Falk-Rønne J, Philipsson J. A radiographic survey of tibiotarsal osteochondrosis in a selected population of trotting horses in Denmark and its possible genetic significance. Equine Vet J 1990;22:288–289.
McIlwraith CW. General pathobiology of the joint and response to injury. In:McIlwraith CW, Trotter GT, ed.Joint disease in the horse. Philadelphia: WB Saunders Co, 1996;40–70.
Boening KJ. Arthroscopic surgery of the distal and proximal interphalangeal joints. In:McIlwraith CW, ed.Diagnostic and surgical arthroscopy in the horse. 3rd ed.Edinburgh: Mosby Elsevier, 2005;347–365.
MacLellan KN, Crawford WH, MacDonald DG. Proximal interphalangeal joint arthrodesis in 34 horses using two parallel 5.5 mm cortical bone screws. Vet Surg 2001;30:453–459.