Femoral lengthening in young patients: An evidence-based comparison between motorized lengthening nails and external fixation

Table 1 Characteristics of the included publications

Ref.	Study design	Patient characteristics	Intervention	Comparator	Clinical outcomes
Black et al[14]	Comparative non-randomized retrospective	(1) Congenital short femur; (2) Skeletally mature children; (3) n = 29 (15 in FITBONE group and 14 in circular external fixation group); and (4) Age (mean): 18.2 yr in FITBONE and 15.8 yr in circular fixators	Motorized lengthening nails (FITBONE)	Circular external fixator	Length achieved, complications rates
Szymczuk et al[13]	Comparative non-randomized retrospective	(1) Congenital short femur; (2) n = 62 (30 in PRECICE group and 32 in LRS group); and (3) Age (mean): 15.4 yr in PRECICE and 9.4 yr in LRS	Magnetic lengthening nails (PRECICE)	LRS external fixator	ROM, length achieved HI and complication rates

Table 2 Findings of the included publications

Black et al[14]
Comparison of FITBONE and circular fixation with respect to several treatment outcomes
Outcome	FITBONE			Circular fixator			P value
Length achieved (cm)	4.4			4.8			0.63
Time to full weight bearing (mo)	7.7			8.8			0.27
Length of F/U (yr)	3			3.6			0.6
Classification of complications according to the authors
Grade	Definition			Example
I	Minimal intervention required; goal still achieved			Pin site infection, mild joint contracture
II	Change to treatment plan, goal still achieved			Unplanned return to theatre, delayed union requiring bone graft.
IIIA	Fail to achieve plan, no new pathology			Premature union, inability to tolerate lengthening, fracture
IIIB	Fail to achieve goal, new pathology/permanent complications			Dislocations, deformity, nerve injury, deep infection
Comparison of FITBONE and circular fixation with respect to adverse events
Complication	FITBONE			Circular fixator			P value
	No. of complications (n = 15)		n (%) of lengthening sessions affected by complications	No. of complication (n = 14)		n (%) of lengthening sessions affected by complications
I	7		5 (33)	15		11 (79)	0.03
II	6		6 (40)	8		6 (43)	0.88
IIIA	4		3 (20)	4		4 (29)	0.68
IIIB	3		3 (20)	6		5 (36)	0.43
Any complication	20		11 (73)	33		14 (100)	0.10
Szymczuk et al[13]
Comparison of PRECICE and LRS fixation with respect to ROM
ROM	PRECICE			LRS fixator			P value
	Extension		Flexion	Extension		Flexion
Preoperative	0.83		127.7	0.47		123.3	0.35
Post-distraction	0.93		96.3	-0.6		69.9	0.0007
Post-consolidation	-0.4		121.5	0.74		81.3	< 0.0001
Final follow up	-0.4		119.6	-0.7		120.2	0.9
Comparison of PRECICE and LRS fixation with respect to several treatment outcomes
Outcome	PRECICE			LRS fixator			P value
Lengthening goal (cm)	4.97			5.58			0.15
Length achieved (cm)	4.75			5.55			0.052
Healing Index (d/cm)	34.77			29.33			0.08
Comparison of complication rates between PRECICE and LRS[22]
Complication	PRECICE			LRS fixator			P value
	Total events	Affected segment		Total events	Affected segments
Problems1, n (%)	8 (25.8)	7(23.3)		32 (55)	20 (62.5)		< 0.001
Obstacle1, n (%)	19 (61)	11 (36.7)		20 (34.5)	10 (31.3)		0.66
Complications1, n (%)	4 (12.9)	4 (13.3)		6 (10.3)	5 (15.6)		0.99
Total, n (%)	31	18(60)		58	26 (81.3)		0.07

¹Problems, obstacles, complications: A classification system of adverse events associated with limb lengthening.

Problems include incidents that do not need operative intervention. Obstacles were the incidents requiring operative but did not lead to permeant complications. Complications included intraoperative injuries and non- resolved problems before the end of treatment.

Table 3 Quality assessment of included publications

Strengths	Limitations
Black et al[14]
(1) Clear methodology: Objective, design, inclusion / exclusion criteria, outcome, and results; (2) Age matched participants; (3) All participants had the same underlying diagnosis; and (4) Complications were described in detail	(1) Clinical and radiological outcome results were not declared due to compassionate use policy; (2) Selection bias; (3) All participants were skeletally mature (not fully representing the Paediatric population); (4) No validated scores were used; (5) No attempt was made to avoid observer bias; and (6) Sample size calculations were not undertaken
Szymczuk et al[13]
(1) Clear methodology: Objective, design, inclusion/exclusion criteria, outcome, and results; (2) The study focused only on children; (3) All participants had the same underlying diagnosis; (4) Probability values (P values) were reported; and (5) Complications were described in detail	(1) Bias such as selection and follow up; (2) There is no mention of potential confounders or how they may have varied between groups; (3) No validated scores were used; (4) No attempt was made to avoid observer bias; (5) Nails were used only in older children, resulting in uneven distribution of the intervention especially in the higher-risk younger age group; and (6) Sample size calculations were not undertaken