1. A 3.5-mm-Diameter Anterior Cruciate Ligament Tibial Retrograde Socket Drilling Pin Is More Accurate Than a 2.4-mm-Diameter Pin 
James H. Lubowitz, M.D., John Konicek, B.S. 
Arthroscopy 
Volume 27, Issue 5, Pages (May 2011)
DOI: /j.arthro
Copyright © 2011 Arthroscopy Association of North America Terms and Conditions

2. Figure 1
Left tibia viewed anterior-posterior. The bioengineer electronically measures and records the perimeter of the ACL tibial footprint by measuring the location of circumferential points using a MicroScribe 3-dimensional digitizer; marked points on the medial tibial plateau provide a fixed-coordinate reference system for 3 sets of digitizer measurements. These data are used to calculate the anatomic center (C) of the footprint.
Arthroscopy  , DOI: ( /j.arthro )
Copyright © 2011 Arthroscopy Association of North America Terms and Conditions

3. Figure 2
ACL C-ring guide (left), tibial marking hook (projecting from guide on left to upper right), and 2.4-mm-diameter drill-tipped guide pin within 2.4-mm-diameter guide pin sleeve (projecting from bottom center to upper right).
Arthroscopy  , DOI: ( /j.arthro )
Copyright © 2011 Arthroscopy Association of North America Terms and Conditions

4. Figure 3
ACL Flipcutter guide (blue, center), tibial marking hook (silver, within guide and projecting from upper center to right), and Flipcutter (blue base and silver pin with black laser marks, projecting from bottom left to upper right; 3.5-mm-diameter guide pin sleeve not shown).
Arthroscopy  , DOI: ( /j.arthro )
Copyright © 2011 Arthroscopy Association of North America Terms and Conditions

5. Figure 4
Left tibia, superior view, with digital projection of ACL tibial footprint in blue. Digital calculation of the anatomic center of the footprint (C) was performed. The distance from C to the surgeon's guess of the footprint center (G) is precision. The distance from G to the guide pin tibial articular exit point (P) is pin accuracy.
(Reprinted with permission.2)
Arthroscopy  , DOI: ( /j.arthro )
Copyright © 2011 Arthroscopy Association of North America Terms and Conditions

6. Figure 5
Pin accuracy is represented as drill pin distance from the surgeon's guess in millimeters, where guess represents the surgeon's marked prediction of the true anatomic center of the ACL tibial footprint. Black diamonds represent the standard 2.4-mm drill-tipped guide pin. Pink squares represent the 3.5-mm retrograde socket drilling pin. The 3.5-mm pin is significantly more accurate.
Arthroscopy  , DOI: ( /j.arthro )
Copyright © 2011 Arthroscopy Association of North America Terms and Conditions

7. Figure 6
Drill pin distance from footprint center (C-P, in millimeters) results from combined effects of imprecision (distance of true anatomic center of ACL tibial footprint from surgeon guess, C-G) and inaccuracy (distance of surgeon guess from actual guide pin position, G-P). Black diamonds represent standard 2.4-mm drill-tipped guide pin subgroup. Pink squares represent 3.5-mm retrograde socket drilling pin subgroup. Illustrated are all 12 samples, representing 2 subgroups. There are no significant differences between subgroups.
Arthroscopy  , DOI: ( /j.arthro )
Copyright © 2011 Arthroscopy Association of North America Terms and Conditions