Fig 1.
The DePuy Synthes TPLO saw guide has a combination of 12 possible positions for attachment to the jig; three angular positioning slots on the guide for the jig pin (A, B, C) and four bolt hole choices for securing the guide to the jig (1, 2, 3, 4).
Fig 2.
Digital representation of the method used to align the jig and guide onto a true-to-size printed postoperative lateral radiograph.
The alignment jig/saw guide was aligned with the long axis of the tibia using the proximal and distal jig pin holes. The saw guide was then positioned to achieve the best fit over the osteotomy by angling the jig arms (see Fig 3). The widest offset along the radial osteotomy between the actual and saw guide osteotomy position was recorded (≤1 mm = excellent; ≤2 mm = good; ≤3 mm = satisfactory; >3 mm = poor).
Fig 3.
After the saw guide was placed in the closest position to the osteotomy, the jig arms were angulated to achieve the best guide-to-osteotomy fit.
The baseline angle of the jig arm was 90°. Angles greater than 90° were recorded as positive and angles below 90° were recorded as negative. The magnitude of the angle was recorded as its total deviation from 90°. This image was reproduced from the DePuy Synthes Vet Technique Guide: “Standard Tibial Plateau leveling Osteotomy (TPLO) System” (J6544-C, 2013), with the courtesy of DePuy Synthes Vet, Inc. West Chester, PA; USA.
Table 1.
The distribution of frequency for each saw guide position as the best guide-to-osteotomy fit for freehand osteotomies based on group.
Table 2.
The distribution of frequency for each saw guide position as the best guide-to-osteotomy fit for the proposed ideal osteotomy location (IOL) based on group.
Fig 4.
Depiction of the osteotomy options available with each of the twelve positions and ±30° from a baseline of 90° angulation of the proximal jig arm.
Each shaded area is a result of angulating the jig arms in each of the positions selected (ABC/1234).
Fig 5.
The proximal jig pin is inserted (dot) parallel to the joint surface and perpendicular to the tibial long axis, 3–4 mm distal to the joint and just caudal to the medial collateral ligament (MCL).