Treatment of distal femur fractures in a regional Australian hospital

Table 1 Biomechanic principles and recommended insertion technique of the Less Invasive Stabilisation System[10,11]

The approach to the distal femur should be minimally invasive, through either a lateral or antero-lateral incision

Stable fixation of the joint fragments is done under direct visualisation

The metaphyseal part of the fracture is reduced in a closed manner under image intensifier guidance. Direct Handling of the fracture is avoided, and the fracture must be reduced before application of the LISS

The LISS implant is inserted sub-muscularly under image intensifier guidance and is positioned alongside the femur.

The LISS is fixed distally and proximally to the femur with locking screws. The screw ratio for the diaphyseal part should be 0.4, meaning that in a 10 hole plate the maximum number of screws should be 4. The diaphyseal screws should have bicortical fixation.

The plate used should have a minimum length of nine holes

Primary bone grafting of the fracture site is not necessary.

LISS: Less Invasive Stabilization System.

Table 2 Comparison of surgical, acute care, rehabilitation and follow-up between implant treatment groups

	Surgical implant				P-value
	LISS(n = 19)	LISS-R(n = 11)	LISS-N(n = 8)	Alternative(n = 8)	LISS vs alternative	LISS-R vs LISS-N	LISS-R vs LISS-N vs alternative
Surgery within first 48 h	11 (58%)	6 (55%)	5 (63%)	6 (75%)	0.6655	1.0000	0.8773
Operation blood loss (mL)	521.1 (296.4)	490.9 (328.5)	562.5 (261.5)	806.3 (925.2)	0.2304	0.6173	0.4761
Operation time (min)	118.4 (24.6)	121.0 (30.0)	114.8 (16.7)	158.5 (42.8)	0.0048	0.5988	0.0187
Length of acute hospital stay (d)	11.7 (6.9)	9.4 (4.6)	14.9 (8.5)	8.9 (6.6)	0.3378	0.0859	0.1357
No rehabilitation	11 (58%)	4 (36%)	7 (88%)	7 (88%)	0.2011	0.0587	0.0308
Rehabilitation less than 14 d	4 (21%)	4 (36%)	0 (0%)	0 (0%)	0.28551	0.10321	0.02681

¹Less than 2 observations in a group makes this P-value unreliable. LISS: Less Invasive Stabilization System.

Table 3 Comparison of primary end points for the implant treatment groups

	Surgical implant				P-value
	LISS(n = 20)	LISS-R(n = 11)	LISS-N(n = 9)	Alternative(n = 8)	LISS vs alternative	LISS-R vs LISS-N	LISS-R vs LISS-N vs alternative
Median Knee Extension (degrees)	0.5 (12.5)	6.0 ( 5.7)	0.0 (18.2)	2.5 ( 9.8)	0.8257	0.9134	0.9698
Median knee flexion (degrees)	96.0 (19.6)	102.0 (13.7)	90.0 (20.2)	90.0 (18.5)	0.8634	0.0143	0.0454
Median lysholm score	57.0 (29.4)	67.0 (30.4)	42.0 (21.9)	56.5 (11.0)	0.9108	0.1809	0.3075
Excellent (> 90)	2 (10%)	2 (18%)	0	0	1.00001	0.47891	0.31481
Good (84-90)	0	0	0	0	NA	NA	NA
Fair (65-83)	2 (10%)	2 (18%)	0	1 (13%)	1.00001	0.47891	0.60711
Poor (< 65)	8 (40%)	4 (36%)	4 (44%)	3 (38%)	1.0000	1.0000	1.0000
Union after 6 mo	14 (70%)	9 (82%)	5 (56%)	5 (63%)	1.0000	0.3359	0.4670

¹Less than 2 observations in a group makes this P-value unreliable. LISS: Less Invasive Stabilization System.

Table 4 Comparison of complication rates for the implant treatment groups n(%)

	Surgical Implant				P-value
	LISS(n = 20)	LISS-R(n = 11)	LISS-N(n = 9)	Alternative(n = 8)	LISS vs alternative	LISS-R vs LISS-N	LISS-R vs LISS-N vs alternative
Complications of healing
Non-union	6 (30)	2 (18)	4 (44)	2 (25)	1.0000	0.3359	0.5065
Delayed union	0	0	0	1 (13)	0.28571	n/a	0.28571
Varus/valgus malalignment	5 (25)	2 (18)	3 (33)	4 (50)	0.3715	0.6169	0.3627
Recurvation	2 (10)	2 (18)	0	0	1.00001	0.47891	0.31481
Limb shortening	3 (15)	1 (9)	2 (22)	1 (13)	1.00001	0.56581	0.80661
Superficial infection	2 (10)	2 (18)	0	0	1.00001	0.47891	0.31481
Implant related complications
Implant malpositioning	2 (10)	1 (9)	1 (11)	n/a2	n/a	1.00001	n/a
Proximal screw pullout	1 (5)	0	1 (11)	n/a2	n/a	0.45001	n/a
Implant failure	4 (20)	1 (9)	3 (33)	1 (13)	1.00001	0.28481	0.46411

¹Less than 2 observations in a group makes this P-value unreliable;

²These complications are LISS specific. LISS: Less Invasive Stabilization System.