EFFECTS OF 3 INTRAMEDULLARY PINNING TECHNIQUES ON PROXIMAL PIN LOCATION AND ARTICULAR DAMAGE IN THE CANINE TIBIA

The effects of three different techniques of intramedullary (IM) pin p lacement on pin location and incidence of stifle joint injury were eva luated using 70 cadaver canine tibiae after middisphyseal osteotomy. I n 50 tibiae, pins were placed retrograde in either a nondirected (grou p A) or a craniomedially directed fashion (group B) with 25 tibiae in each group. Pins were driven normograde (group N) in 20 tibiae. All th e stifles were dissected to qualitatively evaluate pin interference wi th different joint structures. End-on radiographs of the tibial platea us were used to quantitatively evaluate pin location. Interference wit h the caudal cruciate ligament, medial meniscus, lateral meniscus, or meniscal ligaments was not observed in any group. There was a signific ant association between pinning technique and incidence of involvement of the cranial cruciate ligament (P < .005), patella (P < .001), pate llar ligament (P < .005), and femoral condyle (P < .01). Pin location for group A was significantly different from either other group in a c ranial-caudal direction (P = .003), and was significantly different fr om group N in a medial-lateral direction (P = .005). No significant di fference was observed between pin location for groups B and N in eithe r plane. It was concluded that although nondirected retrograde pinning cannot be recommended, retrograde pins directed craniomedially may be an acceptable technique for the repair of proximal to mid-diaphyseal tibial fractures if care is taken to properly seat the pins. (C) Copyr ight 1994 by The American College of Veterinary Surgeons