A technical innovation for improving identification of the trackers by the LED cameras in navigation-assisted total knee arthroplasty

Figures & data

Figure 1. (A) The camera of the system with the laser pointer mounted on top. (B) The trackers fixed on the bone in a TKR operation. (C) The camera identifies the trackers. (D) The laser mark on the lateral femoral condyle approximately 8 cm below the surface of the articular cartilage. If the laser pointer aims in this area, the trackers will be immediately identified by the camera. [Color version available online.]

Figure 2. Graphic representations of (A) the number of times the boom had to change position in both groups with the 95% confidence intervals; and (B) the number of times the boom had to change position at least once in both groups.

Table I.  Patients who underwent a total knee replacement using computer-assisted navigation with (Group B) and without (Group A) the use of a laser pointer. (Patients in each group were numbered after randomization.)

Group A (without laser pointer)			Group B (with laser pointer)
Patient No.	Times boom changed position	Additional time (min)	Patient. No.	Times boom changed position	Additional time (min)
1	9	12	21	2	1
2	11	14	22	2	1.5
3	9	8	23	1	0.5
4	10	13	24	0	0
5	12	16	25	0	0
6	5	8	26	0	0
7	11	16	27	1	1
8	8	10	28	0	0
9	9	10	29	0	0
10	9	8	30	0	0
11	11	15	31	1	0.50
12	10	14	32	2	1.50
13	8	9	33	0	0
14	9	11	34	0	0
15	7	10	35	3	2
16	12	15	36	1	0.50
17	6	8	37	0	0
18	9	12	38	2	1
19	11	13	39	1	1.50
20	7	9	40	1	1