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Treatment Of Distal Femoral Fractures Using The Less Invasive Stabilisation System (LISS) Plates

Shreya Srinivas*,  Michael Maru**, Cathy Lennox #

*Research fellow, Centre for Spinal Surgery and Studies, Queens Medical Centre, Nottingham
Specialist Registrar, Trauma and Orthopaedics, Northern deanery
#Consultant Orthopaedic Surgeon, University hospital North Tees and Hartlepool

Address for Correspondence:  

Macclesfield, Cheshire SK10 3LT



Purpose: To review clinical and radiological outcome of distal femoral fractures treated with the Less Invasive Stabilisation System (LISS).

Methods: Retrospective observational study of all distal femoral fractures treated with LISS between 2003 and 2007 in three trauma centres.

Results: A total of 40 patients were identified. Amongst these, 3 patients were lost to follow up or died and 37 patients (24 females and 13 males) were included in final analysis. There were 23 acute femoral fractures and 14 periprosthetic fractures. The commonest cause of injury was simple mechanical fall. According to the AO classification, 15 patients with type 33A, 4 patients with type 33C,  13 patients with type 32A and 2 patients with  type 32B and 3 patients with type 32C . Overall, the mean age was 67+/- 23.62 (Mean+/-SD) years. Follow up period was 12+/-6.92 (Mean+/-SD) months. At the time of follow-up, fractures in 25 patients had united and the remaining patients were proceeding to union. Average time to union was 4.0+/-1.48(Mean+/- SD) months. One patient died 13 months after fixation of fracture. Twenty seven patients had closed reduction.

Conclusion: LISS technique can achieve 100% union rate in both acute distal femoral and periprosthetic fractures. Most fractures proceed to union without the need for primary bone grafting and there were no deep infections, thromboembolic events, persistent pain or malunion. However, the procedure requires careful planning and experience in the operative technique.

J.Orthopaedics 2008;5(4)e10


Less invasive stabilisation system plates; distal femur; fractures; periprosthetic fractures.


Fractures of the distal femur are complex injuries that account for 7% of all femoral fractures [1] and their surgical treatment has always remained a challenge for the orthopaedic surgeon. [2]

The goals of surgical treatment are to restore anatomical congruity and achieve a stable fracture fixation that will allow early mobilisation.

The results with surgical treatment are now favourable consequent to the advances in implant technology and surgical techniques seen in the last 40 years. From 1990 onwards, the decade saw the evolution of minimally invasive surgical techniques in the fixation of distal femoral fracture.

Studies were undertaken to develop a system that can combine the principles of a fixed angle construct (biological plating techniques) that provides angular stability and the soft tissue preservation that can be achieved with intramedullary nailing devices. [3] The end result of these studies was the less invasive stabilisation system (LISS). The LISS has been shown to provide a stable fracture fixation with soft tissue preservation and has now gained popularity in treatment of distal femoral fractures and in fractures around an implant (periprosthetic fractures).

However, owing to the recent evolution of this system, there are very few clinical studies undertaken in UK, so far, which have published the outcome with the LISS technique.

We therefore undertook a multi centre retrospective study to assess the outcome with LISS technique in treatment of distal femoral fractures in three trauma units.

In this paper, we present our results with respect to the clinical and radiological outcome achieved and discuss our experience with LISS technique.

Material and Methods :

A retrospective review of all patients who underwent surgical fixation with the LISS technique for distal femoral fractures in three trauma units in North East England (2 district general hospitals and 1 tertiary referral centre) was undertaken between 2004 and 2007.

A total of 40 cases of distal femoral fractures underwent LISS procedure during the period of review. Two patients were lost to follow up and another died at 3 months due to causes unrelated to surgery and these 3 patients were excluded from our study.

Therefore, only 37 patients were included in the final analysis and a review of case notes and radiographs of these patients were undertaken by the authors.

We noted the patient demographics with relation to age and gender. Details about the mechanism of initial injury, type of fracture (open or closed) and presence of periprosthetic fracture was recorded. Initial plain radiographs were reviewed and all fractures were classified according to the AO system.

Intra-operative information about surgical technique with regards fracture reduction, intra-operative complications and post operative mobilisation instructions were obtained from the operative notes. 

Clinical and radiological outcome with regard to bony union, post-operative complications and incidence of post-operative infection was assessed from the follow up outpatient clinic notes and radiographs. Simple statistics were used where possible.

Results :

Between 2003 and 2007, forty patients underwent LISS plate fixation for treatment of distal femoral fractures. The case notes and radiographs of 37 patients were available for final analysis.

There were 23 cases of distal intra and extra articular acute femoral shaft fractures (AO/OTA Type 32 and 33) treated with LISS during the period of review.

There were 14 cases of periprosthetic fractures and the results are discussed separately. 

Acute Femoral shaft fractures:  

The mean age at time of operation was 62.74 +/- 26.90 years (mean +/- SD). Range (18 – 102 years).

The commonest mechanism of injury was simple mechanical fall (n= 13) and other cause of injury was a road traffic accident [RTA] (n= 10).  There were two cases of compound fracture. According to the AO classification, 11 patients with type 33A, 4 patients with type 33C, 6 patients with type 32A and 1 patient each with  type 32B and 32 C respectively. (Table 1) There were 2 cases of compound fracture.

Fracture Type












TABLE 1. AO/OTA Fracture classification in acute femoral fractures

Early post operative mobilisation was encouraged in all patients. Post operative weight bearing status depended on practice of the operating surgeon. In 11 cases, patients were initially mobilised non weight bearing for 6 weeks and in the other 12 cases, patients were allowed to partially weight bear for 6 weeks immediately after the operation. The average follow up of patients was 11.77 +/- 8.72 months (mean +/- SD). All patients were being followed up until bony union was evident on plain radiographs.  At the time of follow-up, plain radiographs showed that the fractures in 20 patients had united and the remaining three patients were proceeding to union with evidence of good callus formation. The average time to union was 4.0 +/- 1.33 months (mean+/- SD).

Complications: Indirect fracture reduction with closed technique was achieved in 15 patients but in 6 patients, direct open reduction was necessary to achieve adequate reduction of fracture (28.5%). Post operative early failure of fixation was seen in 1 case because of a short plate being used. This was revised within 6 weeks using a longer holed plate and satisfactory union was seen at follow up. Another case of screw pull out was noted on x-ray but overall fracture fixation was stable. 1 patient died 13 months after fixation of fracture due to causes unrelated to the fracture fixation.

There was no incidence of deep infections, thromboembolic events, persistent pain or malunion seen.

Periprosthetic fractures: 

Amongst the cases included in our review, there were 14 cases of periprosthetic fractures. The fractures occurred in 7 cases around a Total hip replacement and in 6 cases around a Total knee replacement. One patient had both a hip and knee prosthesis in situ. There was 1 compound fracture. Mean age of patient was 73.64 +/- 14.22 years. (Mean +/- SD).The mechanism of injury in 13 patients was a simple fall. Fracture classification is outlined in Table 2.

Fracture Type










TABLE 2. AO/OTA Fracture classification of periprosthetic fractures

In two cases, fractures occurred during primary total hip replacement and in addition to the LISS, cables were used to achieve fracture fixation in these 2 cases. Patients were allowed to commence partial weight bearing mobilisation for 6 weeks following the operation in all but 4 cases where patients remained non weight bearing for initial 6 weeks. Patients were followed up for 11.5 +/- 5.16 months (mean +/- SD) and average time to union was 4.54 +/- 1.69 months (mean +/- SD). All fractures proceeded to bony union.


In 4 cases, indirect fracture reduction was not possible and minimal open incision was required for adequate reduction (30.7%). No failure of fixation was seen. There was no incidence of deep infection or thromboembolic events. The findings are summarised in Table 3.


Acute femoral fractures

Periprosthetic fractures


Age (mean+/-SD)

62.74 +/- 26.90

73.61 +/- 14.80

67+/- 23.62









High energy

Low energy







Post op mobilisation












Follow up(mean+/-SD)




Time to union(mean+/-SD)

4.0+/- 1.33



Failure of indirect reduction*







TABLE 3. Patient characteristics in distal femoral fractures
*open fractures were excluded

Discussion :

Many treatments for distal femoral fractures have been advocated in the past years.

In 1960s, clinical studies showed that non operative treatment was more successful in these fractures but it remained a serious cause of disability. Invariably the patients had a stiff knee but the results obtained with surgical fixation were unfavourable as well. [15] The introduction of the AO angled blade plate in 1970 however reversed this trend. With subsequent advances in implant technology and surgical techniques, it is now accepted that these fractures are best treated with surgical fixation to achieve a good functional outcome [2].

Less Invasive Stabilization System (LISS) has been designed to provide a stable biomechanical fixation while preserving the blood supply to the bone with minimal soft tissue disruption. The locked screw plate construct has greater angular stability than compression plating devices with lesser incidence of implant failure and has thus gained popularity in the treatment of supracondylar femoral fractures in the last decade [4-6].

The widely accepted indications for use of this technique are periprosthetic fractures, intra and extra articular diaphyseal fractures [8].

Figure1: Clinical Case pre-operative radiographs distal femur AP and Lateral

Figure 2: Post-operative radiographs showing fracture union

The LISS acts as a splint and its function as an internal fixator offers relative stability and results in indirect bone healing with callus formation. Therefore, in contrast to compression plating, the LISS plate does not have to be in direct contact with the bone. This reduces soft tissue dissection and preserves the blood supply to the periosteum. This not only reduces the incidence of infection but also helps with early post operative mobilisation. A low infection rate is reported with LISS technique (0-8%) [4-8] and in our study there are no cases of superficial or deep infections reported.

The biomechanical principle used during the evolution of the LISS technique was to develop an implant which would resist failure until after fracture healing [3,9]  and a biomechanical comparison of 4 different constructs used in treatment of distal femoral fractures has shown that LISS has improved distal fixation especially in osteoporotic bone [9].

Early clinical studies evaluating the efficacy and outcome of the LISS technique have reported union rates of 93% - 100%. [4,5,7] The average time to bony union is between 3.5 to 4.5 months [4-6]. As evidenced in our study, we were able to achieve 100 % union rate with LISS technique. The average time to union noted in our study was 4 months and this is similar to the average time reported in other studies.  

Giving particular attention to the management of periprosthetic fractures, the incidence is 0.3% to 2.5 % [10]. The trend in management of periprosthetic fractures has been surgical fixation with either intramedullary nailing devices such as a retrograde nail, rush or enders nail and the angled blade plate. The outcome has been reasonable with a complication rate of 30%. [11]

However, in recent years, LISS technique has emerged as an ideal technique of fixation in the treatment of periprosthetic fractures around the knee. When compared to other fixation methods such as compression plate and intramedullary nailing, there were fewer instances of failure of fixation and resultant varus angulation in fractures treated with LISS technique. It offers better return of function and early mobilisation. The other advantages are that there is no need for acute bone grafting, a low risk for infection and is associated with minimal blood loss. A recent review of the management of periprosthetic fractures has shown that modern treatment options in surgical fixation are better than conventional techniques of open reduction and compression plating or non operative management [12].

In our case series, we have treated 14 cases of periprosthetic fractures. All cases proceeded to union (100% union rate) with no need for primary bone grafting. We were able to achieve early postoperative mobilisation and patients were allowed to partially weight bear in all but 4 cases.  No cases of deep infection or failure were seen.

One of the challenges we encountered with LISS technique was achieving adequate fracture reduction using a closed/indirect technique. In our study, 10 cases required open reduction (4 periprosthetic, 6 distal shaft fractures 29.41%).

Of these 10 cases, 5 cases were Type C fractures and open reduction was probably required to visualise the articular surface to help anatomical reduction and restore joint congruity. The other possible explanations are complex fracture pattern, inexperience of the surgeon and inadequate closed reduction. These difficulties can be overcome by careful surgical planning.

Early studies comparing the outcome of LISS plating have highlighted its limitations in less experienced hands and that inadequate operative experience and inappropriate technique can result in suboptimal fixation [1]. However one study found this system user-friendly with no major technical difficulties [5].

Technical tips suggested in helping fracture reduction include use of femoral distracters or Schanz screws (joy stick). Additional aids described to achieve an appropriate reduction include percutaneous clamps and a bone hook. [4] The surgical assistant can also aid fracture reduction with posterior support of the distal fragment to overcome the resistance of the gastrocnemius muscle. Fixation with a k-wire will help maintain the fracture reduction.

One of the identified causes of failure of fixation in LISS plating is an incorrectly placed plate. The plate has a tendency to externally rotate against the lateral femoral condoyle [1] and this can be overcome by taking precautions to fix the plate parallel to the femur. A cadaveric study has shown that plates fixed in external rotation are more prone to failure [14].  In our case series, only 1 case was noted to have a less than satisfactory fixation due to shorter plate being used. This was revised within 6 weeks and a longer 15 hole plate was used to achieve satisfactory reduction. At time of final follow up the fracture was united with no further complications. 

Other complications noted with LISS technique have been delayed union (11%) and malreduction (6%) and plate breakage (2%) [4,13] but in our study we have not encountered any of these complications.

Conclusion :

We were able to achieve a 100% union rate with LISS technique in both acute distal femoral and periprosthetic fractures. There was no primary bone grafting required and no incidence of infection was noted.

The LISS technique offers the advantages of a stable construct with minimal soft tissue disruption.

However the procedure requires careful surgical planning and experience in the operative technique is paramount.

Reference :

  1. O’Brien P J, Meek RN, Blachut PA, Broekhuyse H. Fractures of distal femur in Rookwood and Green 6th ed; Vol 2; Chapter 48; Pg 1915- 1938.

  2. J. H. Newman .Fractures of the femur, Injury (1990) 21, 280-282

  3. Frigg R, Appenzeller A, Christensen R, Frenk A, Gilbert S, Schavan R. The development of the distal femur less invasive stabilization system (LISS). Injury 2001; 32:24–31.

  4. Kregor PJ, Stannard JA, Zlowodzki M, Cole PA. Treatment of distal femur fractures using the less invasive stabilization system: surgical experience and early clinical results in 103 fractures. J Orthop Trauma 2004;18:509–20 

  5. Syed AA, Agarwal M, Giannoudis PV, Matthews SJE, Smith RM. Distal femoral fractures: long-term outcome following stabilization with the LISS. Injury 2004;53:599–607

  6. Wong MK, Leung F, Chow SP. Treatment of distal femoral fractures in the elderly using a less-invasive plating technique. Int Orthop. 2005 Apr; 29(2):117-20.

  7. Ricci AR, Yue JJ, Taffet R, Catalano JB, Defalco RA, Wilkens KJ. Less invasive stabilization system for treatment of distal femur fractures. Am J Orthop 2004;33:250–5

  8. Less Invasive Stabilization System (LISS) © 2000 SYNTHES (USA) TECHNIQUE GUIDE. Original Instruments and Implants of the Association for the Study of Internal Fixation —AO ASIF           

  9. Zlowodzki M, Williamson S, Cole PA, Zardiackas LD, Kregor PJ. Biomechanical evaluation of the less invasive stabilization system, angled blade plate, and retrograde intramedullary nail for the internal fixation of distal femur fractures. J Orthop Trauma. 2004 Sep; 18(8):494-502.

  10. Althausen PL, Lee MA, Finkemeier CG, Meehan JP, Rodrigo JJ. Operative stabilization of supracondylar femur fractures above total knee arthroplasty: a comparison of four treatment methods. J Arthr 2003; 18:834–9.  

  11. Chen F, Mont MA, Bachner RS.Management of ipsilateral supracondylar femur fractures following total knee arthroplasty. J Arthroplasty. 1994 9(5):521-6.

  12. Herrera DA, Kregor PJ, Cole PA, Levy BA, Jönsson A, Zlowodzki M. Treatment of acute distal femur fractures above a total knee arthroplasty: systematic review of 415 cases (1981-2006). Acta Orthop. 2008 Feb; 79(1):22-7.

  13. Schultz M, Muller M, Krettek C, Hontzsch D, Regazzoni P, Ganz R, et al. Minimally invasive fracture stabilization of distal femoral fractures with the LISS: a prospective multicenter study. Results of a clinical study with special emphasis on difficult cases.Injury 2001;32: 48–54. 

  14. Khalafi A, Curtiss S, Hazelwood S, Wolinsky P.The effect of plate rotation on the stiffness of femoral LISS: a mechanical study. J Orthop Trauma. 2006 Sep; 20(8):542-6. 

  15. A P Whittle. Fractures of the Lower extremity in Campbell’s Operative Orthopaedics Eleventh ed; Vol III; Chapter 51; Pg 3085.(Book Chapters)


This is a peer reviewed paper 

Please cite as :Shreya Srinivas : Treatment Of Distal Femoral Fractures Using The Less Invasive Stabilisation System (LISS) Plates

J.Orthopaedics 2008;5(4)e10





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