How precise is the PRECICE compared to the ISKD in intramedullary limb lengthening?

Figures & data

Figure 1. A PRECICE nail transected with a laser. The integrated magnet (arrow) is visible on the threaded rod.

Figure 2. Application of the external remote controller. The weak magnetic field has to be pressed as much as possible into the soft tissue. A range of 5.5 cm is the maximum distance for proper functioning of the magnetic device.

Figure 3. The application level depends on the positioning of the magnet, which can be identified in relation to the osteotomy level on the radiograph (see arrow).

Figure 4. Radiograph from a 16-year-old boy, 6 months after implantation of a femoral PRECICE with a trochanteric approach for lengthening of 50 mm. After 3 months (35 mm), repeat osteoclasia due to early consolidation had become necessary. Breakage of the welding seam (arrow) occurred a further 3 months later, 1 month after the end of the distraction period.

Figure 5. Nail breakage at the welding seam in the PRECICE device in the patient shown in Figure 4.

Table 1. Empirical data for the group of 24 patients who underwent surgery with 26 implantations of a PRECICE device, and reliability of the device

	Femoral lengthening	Tibial lengthening	Total
Patients (implanted PRECICE nails), n	19 (20)	5 (6)	24 (26)
Mean age (range) at surgery, years	20 (12–31)	17 (13–21)	19 (12–31)
Median age, years	17	17	17
M/F, n	6/13	4/1	10/14
Treatment completed with PRECICE, n	19/20	5/6	24/26
Dropout rate, unsuccessful PRECICE, n ^a	1/20	1/6	2/26
Secondary failure of PRECICE, n ^b	1/20	1/6	2/26
Overall reliability of PRECICE, n	18/20	4/6	22/26

^a Bony consolidation or full weight bearing not achieved with PRECICE.

^b The PRECICE device broke or was removed or exchanged before bony consolidation was achieved, but after the desired lengthening had been reached.

Table 2. Results for 23 patients with implantation of 24 PRECICE nails and successful lengthening of the bone: accuracy of lengthening, implant-associated problems, obstacles, and complications

A	B	C	D	E	F	G	H	I	J	K	L
1	16	50	FA	50	Yes	50	0.00	0.4	1	1 ^a	1 ^a
2	18	28	FA	30	No	28	0.93	1.1	1
3	23	107	FA	50	Yes	50	0.00	0.3	1
4	16	80	FA	30	Yes	30	0.00	0.4	1		1
5	16	50	FA	50	Yes	49	0.98	0.8	1
6	19	40	FA	35	No	35	0.00	0.6
7	12	47	FA	50	Yes	50	0.00	0.9	1
8	17	44	T	44	No	38	0.86	0.7	1	1 ^a	1 ^a
9	16	50	FA	40	No	40	0.00	0.9
10	15	50	FA	50	Yes	50	0.00	1.4	1
11	13	48	T	48	Yes	45	0.94	0.3	1	1
12	29	50	FA	35	No	35	0.00	1.3
13	16	50	FA	50	No	44	0.88	1.3	1	1
14	17	35	T	35	Yes	35	0.00	0.7	1
15	29	30	FR	25	No	25	0.00	0.5
16	17	25	FR	20	No	20	0.00	0.5
17	15	25	FA	25	No	25	0.00	0.9	1
18	19	23	FA	23	No	23	0.00	0.8
19	32	23	FR	23	No	23	0.00	0.6
20	20	15	FA	23	No	15	0.65	0.5
21	16	53	FA	50	No	50	0.00	0.8	1
22	18	50	FR	50	No	50	0.00	0.9	1	1	1
23	21	0	T	50	Yes	49	0.98	0.4
			0	T	50	Yes	51	0.98	0.4	1
Total					Yes = 10				15	5	4
Average	18			38		37	0.97	0.8	0.6	0.2	0.2

^a Patients with nail breakage during the consolidation period who required exchange nailing.

A Patient no.

B Age

C Limb length discrepancy, mm

D Bone approach

 FA: femoral antegrade trochanteric entry

 FR: femoral retrograde entry

 T: tibial

E Distraction planned, mm

F ECR adjustment

G Distraction achieved, mm

H Accuracy ratio (ratio of distraction achieved to that planned)

I mm/day

J Problems

K Obstacles

L Complications