Displays mounted on cutting blocks reduce the learning curve in navigated total knee arthroplasty

Figures & data

Figure 1. Set-up of the navigation system in the operating theater. A navigated TKA of the right knee is being performed. Note the display positioned off to the side of the operation site.

Figure 2. The use of the Dash® device with the integrated display. The display is fixed on the cutting block, and no external display is required.

Figure 3. Overview of the study set-up. The Kolibri® device is shown on the left and the Dash® device on the right. Identical knee models with identical reference arrays were used at both workstations. The infrared cameras of both systems were positioned at the foot of the virtual patients.

Figure 4. A student adjusts the cutting blocks using the Kolibri® device. During the procedure, an optical array was fixed on the tibial and femoral cutting blocks.

Table I.  Time requirements for adjustment of cutting blocks for both groups.

	Dash device			Kolibri device
	Tibial (s)	Femoral (s)	Total (tibial + femoral) (s)	Tibial (s)	Femoral (s)	Total (tibial + femoral) (s)
Dash group
Trial 1	60	47	106	78	63	141
Trial 2	44	33	77	38	65	103
Trial 3	31	28	59	30	42	71
Mean value	45	36	81	49	56	105
Std. dev.	19	11	25	22	27	43
Range	15–160	14–129	33–238	11–215	13–233	32–295
Kolibri group
Trial 1	41	41	82	70	88	158
Trial 2	34	28	62	56	48	104
Trial 3	27	25	52	32	37	69
Mean value	34	32	66	53	58	110
Std. dev.	11	9	17	28	24	42
Range	16–89	13–80	29–169	12–210	14–220	29–362
All students
Mean value	40	34	73	51	57	108
Std. dev.	16	10	23	25	25	42
Range	15–160	13–129	29–238	11–215	14–233	29–362

Figure 5. The total time requirement for adjustment of the tibial and femoral blocks. Using the integrated display (the Dash® device), the time requirement was significantly reduced by 32% (73 s vs. 108 s, p < 0.001).

Table II.  Time for adjustment of each cutting block using the Dash and Kolibri devices.

		Dash device (s)	Kolibri device (s)	Level of significance
Dash group	Tibial	45	49	0.346
	Femoral	36	56	0.005*
	Total	81	105	0.006*
Kolibri group	Tibial	34	53	0.007*
	Femoral	32	58	0.001*
	Total	66	110	0.001*
All students	Tibial	40	51	0.007*
	Femoral	34	57	<0.001*
	Total	73	108	<0.001*

*Significant differences as determined by Wilcoxon test with significance set to α = 0.05