CONTACT AREA AND STATIC PRESSURE PROFILE AT THE PLATE-BONE INTERFACE IN THE NONLUTED AND LUTED BONE PLATE

Contact area and pressure between 6-hole broad dynamic compression pla tes and 20 pairs of equine third metatarsal bones were measured using nonluted and luted plating techniques. Pressure-sensitive film (pressu re ranges 10 to 50 MPa and 50 to 130 MPa) was used as the static press ure transducer. Nonluted and one of two luting techniques were tested on each pair of bones; each luting technique was tested on 20 bones. Q uantitative determinations of contact area and pressure were made usin g computerized image processing techniques. Mean (+/-SD) total contact area for nonluted plates was 18.49% +/- 3.5% of the potential plate-b one contact area. Luting increased (P <.05) total contact area to 25.5 6% +/- 4.0% and 31.29% +/- 6.6% for the respective luting techniques. The effects of luting on contact area were dependent on the contact pr essure. At contact pressure ranges 10 to 20 and 21 to 35 MPa, luting i ncreased contact area. In contact pressure ranges 36 to 45 and 50 to 6 5 MPa, plate-bone contact was inherently greatest and plate luting had no significant effect on contact area. In contact pressure ranges 66 to 99 and 100 to 126 MPa, luting decreased contact area. Contact area was increased at lower contact pressures at the expense of higher pres sure contact. Contact in the middle third of the plate was 20% to 40% of the contact at either end of the plate. Plate luting increased cont act area best where plate-bone contour was most similar. (C)Copywright 1995 by The American College of Veterinary Surgeons