Lower limb malrotation following MIPO technique of distal femoral and proximal tibial fractures

Injury, Int. J. Care Injured 42 (2011) 194–199

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Lower limb malrotation following MIPO technique of distal femoral and proximal tibial fractures R. Buckley a,b,*, K. Mohanty c,1, D. Malish d a

Foothills Medical Centre, AC144A, 1403 – 29th Street NW, Calgary, AB, Canada T2N 2T9 Department of Surgery, Foothills Hospital, Calgary, AB, Canada T2N 2T9 c 1 Ochr Y Coed, Thornhill, Cardiff CF149GB, UK d 3330 Hospital Drive NW, Calgary, AB, Canada T2N 4N1 b

A R T I C L E I N F O

A B S T R A C T

Article history: Accepted 18 August 2010

Objective: To determine the incidence of rotational malalignment in distal femoral and proximal tibial fractures using computed tomography (CT) scanograms following indirect reduction and internal fixation with the minimally invasive percutaneous osteosynthesis (MIPO) technique. Design: Prospective Cohort. Setting: Level I Trauma Centre. Patients/Participants: A total of 27 consecutive subjects, and 14 proximal tibia and distal femur fractures. Intervention: All patients underwent indirect reduction and internal fixation with a MIPO plating system. A CT scanogram to measure rotational malalignment between the injured and non-injured extremity was then undertaken. Main outcome measure(s): Femoral anteversion angles and tibial rotation angles between the injured and non-injured extremities were compared. Malrotation was defined as a side-to-side difference of >108. Results: A total of 14 postoperative tibias and 13 femurs underwent CT scanograms. Three females and 11 males with an average age of 38.1 years sustained proximal tibia fractures and six females and seven males with an average age of 55.8 years sustained distal femur fractures. The difference between tibial rotation in the injured and the non-injured limbs ranged from 2.7 to 40.08 with a mean difference of 16.28 (p = 0.656, paired T-test). Fifty percent of the tibias fixed with MIPO plates were malrotated >108 from the uninjured limbs. The difference between femoral anteversion in the injured and non-injured limbs ranged from 2.0 to 31.38 with a mean difference of 11.58 (p = 0.005, paired T-test). A total of 38.5% of the distal femurs fixed with MIPO plates were malrotated >108 from the uninjured limb. Conclusions: Following fixation of distal femoral and proximal tibial fractures, the incidence of malrotation was 38.5% and 50%, respectively. The difference of the mean measures was significant for femoral malrotation; however, statistical significance could not be demonstrated for tibial malrotation. The incidence of malrotation following MIPO plating in this study is much higher than that quoted in previous studies. ß 2010 Elsevier Ltd. All rights reserved.

Keywords: Fracture MIPO Malrotation CT scanogram Malunion

Introduction With the popularity of biological fixation, minimally invasive percutaneous plating is now being used more frequently at trauma centres around the world. Published reports have shown good outcomes, including shorter healing time and lower re-operation rates.9,10,20,33,36–38,48 Indirect fracture reduction to achieve restoration of anatomic length, alignment and rotation in an injured

* Corresponding author at: Foothills Medical Centre, AC144A, 1403 – 29th Street NW, Calgary, AB, Canada T2N 2T9. Tel.: +1 403 944 8371; fax: +1 403 270 8004. E-mail address: [email protected] (R. Buckley). 1 Tel.: +44 2920 753738; fax: +44 2920 753738. 0020–1383/$ – see front matter ß 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2010.08.024

extremity can be extremely challenging. Closed, minimally invasive techniques with indirect fracture reduction can lead to higher rates of limb malalignment.24,29,34,44 Limb malalignment can have deleterious effects on adjacent joints and articular cartilage. Rotational deformity in the lower extremity has been shown to influence articular cartilage shearing and the development of earlier joint arthrosis, leading to clinically relevant degenerative changes.12,18,22,25,42 Several large studies looking at tibial intramedullary (IM) nails showed that the incidence of malrotation ranged anywhere from 0% to 6% when measured clinically.1,4,11,21,27,46 Similarly, earlier studies clinically assessing malrotation in femoral shaft fractures treated with IM nails report incidence rates ranging from 0% to 7%.2,45 Clinical examination and side-to-side comparison of limbs

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has been shown to underestimate the degree of malrotation present postoperatively. Computed tomography (CT) scanograms of lower extremities using standard protocols to assess femoral anteversion and tibial torsion indicate that the degree of malrotation in tibial and femoral fractures treated with closed reduction and IM nailing can be as high as 22% and 55%, respectively.5,13,28,41 CT scanograms have become the ‘gold standard’ for assessing lower extremity malrotation with good demonstrated intra- and inter-observer reliability and repeatability.28 The quality of reduction and limb alignment with the use of the L.I.S.S. system (‘Less Invasive Skeletal Stabilisation’ system – L.I.S.S., Synthes, Paoli, PA, USA) has not been well documented. The few studies that have documented post-reduction limb rotation following minimally invasive percutaneous osteosynthesis (MIPO) plate fixation quote an incidence of malrotation >10 in 0–9% of limbs based on clinical examination and on side-to-side comparison with the uninjured extremity.7,19,30,39,43 The primary objective of this study was to determine the incidence of lower extremity malrotation in a prospective cohort of patients with distal femoral and proximal tibial fractures treated with the L.I.S.S. plating system using a standard lower extremity postoperative CT scanogram protocol. Patients and methods Scientific and ethical approval to proceed with this prospective study was obtained from the Conjoint Health Research Ethics Board. The study design was a prospective cohort based at the local Level 1 Trauma Center. A consecutive series of 38 eligible patients with either distal femoral or proximal tibial fractures treated with L.I.S.S. plate fixation were approached to be enrolled in the study. A total of 27 patients consented to enter the study. As many as 11 patients declined entry or were unreachable. All patients, who had L.I.S.S. stabilisation for distal femoral and proximal tibial fractures, were considered for enrolment in this study. Inclusion criteria consisted of both closed and open fractures, periprosthetic fractures and intra-articular and extraarticular metaphyseal fractures. Only unilateral fractures were included. Pregnant females, patients with claustrophobia to the CT scanner and patients with other fractures, fixation or revision of previous fixation in either the ipsilateral or the contralateral femur or tibia were excluded from the study. The decision to proceed with MIPO plate fixation of a distal femoral or proximal tibial fracture was made by the attending staff surgeon. The attending staff surgeon was, each time, a senior attending staff surgeon and was present for all of the surgery that was provided to the patients. All patients underwent treatment of their injury based on the surgeon’s standard treatment protocols. Poly-traumatised patients were treated in conjunction with the trauma and intensive care services until when they were appropriately stabilised and ready for the operating room. The standard operating room set-up for MIPO plating with a fracture table and intra-operative fluoroscopy was used in each case. Standard principles for treating open fractures were followed, although no application of external fixators or staged reconstructions was necessary. Strict adherence to definitive AO fracture treatment principles included open reduction of any intra-articular fractures, indirect reduction of metaphyseal and metadiaphyseal fractures and minimally invasive plate application and fixation using fluoroscopic guidance. All 38 patients who had L.I.S.S. fixation in our institution during the study period were approached to enrol in the study postoperatively and 27 patients consented to participate. Chart notes were studied for demographics, mechanism of injury and type of fracture. All preoperative X-rays were reviewed and classified using the AO/Orthopaedic Trauma Association (AO/OTA)

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classification system. Prior to hospital discharge, a CT scan of both lower extremities was conducted based on a standard protocol for assessing femoral version angle and tibial rotation.15,16,23,26 The same General Electric Lightspeed Quadratic Multislice scanner was used in each case. Patients were scanned in the supine position with adjustable supports to prevent movement of their lower extremities. Scanning included multiple 5-mm cuts at the proximal femur, distal femur, proximal tibia and distal tibia. The femoral version angle was calculated using the difference between the angles of the axis of the femoral neck and the posterior femoral condyles at the level of the transepicondylar axis with a horizontal reference line on the scan (Fig. 1). The tibial torsion angle was calculated using the difference between the angles of the transcondylar axis at a level just proximal to the fibular head and the transmalleolar axis just proximal to the tibial plafond with a horizontal reference line on the 129 scan (Fig. 2). Each measurement was taken on three different occasions by a fellowship-trained radiologist, and the mean calculated to reduce intra-observer variability. Negative angles denote internal tibial torsion and femoral retroversion while positive angles indicate external tibial torsion and femoral anteversion. Measurements for the injured and non-injured extremity were recorded and the sideto-side difference was calculated. The mean rotational difference between limbs was then calculated for the femurs and tibias and a range of rotational differences was recorded along with the standard deviation. A side-to side difference in tibial torsion and femoral version angles >108 were considered a significant degree of malrotation based on previous references. The incidence of

[(Fig._1)TD$IG]

Fig. 1. Selected axial CT images of the (a) proximal and (b) distal femur demonstrating the method of measuring the femoral anteversion angle. The difference in anteversion angle between the injured and uninjured extremity indicated the degree of malrotation postoperatively.

[(Fig._2)TD$IG]

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Fig. 2. Selected axial CT images of both the injured and uninjured (a) proximal and (b) distal tibias of a postoperative patient. The side-to-side difference in the calculated tibial rotation angles between the injured and uninjured extremities was used to indicate the degree of tibial malrotation.

malrotation for the femurs and tibias was calculated along with a paired T-test to determine if the difference between the mean measurements was significant. Results Of the 27 patients enrolled in the study, 13 had distal femoral fractures and 14 had proximal tibial fractures. Injuries included both high- and low-energy mechanisms from simple falls, falls from a height, motor vehicle crashes and one-blast injury. In the

femur fracture population, six patients were female and seven were male at an average age of 55.8 years. Using the AO/OTA classification, six 33.A1, four 33.A2, one 33.A3, one 33.C1 and one 33.C2 fractures were identified. No femur fractures were open. The proximal tibial fracture population included three females and 11 males at an average age of 38.1 years. The number of fractures was classified as three 41.A2, four 41.A3, four 41.C1, one 41.C2 and two 41.C3. Three Gustillo-Anderson Grade II open fractures occurred. All were AO/OTA type A fractures. For the 14 tibia fractures, the postoperative rotational difference between the injured and non-injured extremities ranged from 2.7 to 40 (Table 1). The mean rotational difference between limbs was approximately 16.2 with a standard deviation of 12.8. Using a previously described malrotation classification,17 excellent results (0–5) were obtained in four (29%), good results (6–10) were obtained in three (21%), fair results (11–20) in two (14%) and poor results (>20) in five (36%). Fifty percent of fractures were reduced with difference in the degree of malrotation >10 from the contralateral normal limb. There were four 41.C1, one 41.C2, one 41.C3 and one 41.A3 fractures malrotated >10. The four 41.C1 and one 41.C2 fractures were malrotated >20. However, the statistical difference between the mean measures of rotational difference was not significant at a p-value of approximately 0.656, suggesting that this group was underpowered. Similarly for the femur fractures, postoperative rotational difference between the injured and non-injured extremities ranged from 2.0 to 31.3 (Table 2). The mean degree of malrotation was approximately 11.58 with a standard deviation of 10.3. Classifying the degree of malrotation, six (47%) were excellent, two (15%) were good, two (15%) were fair and three (23%) were poor. Five of 13 fractures (38.5%) were malrotated >10 compared with the contralateral limb. Six fractured extremities had version angles that were retroverted, suggesting that the distal femoral fracture fragment was relatively externally rotated compared with the contralateral limb. There were four 33.A1 and one 33.A2 fractures that were malrotated >10, while two 33.A1 and one 33.A2 fractures were malrotated >20. The difference between the mean measures of rotational difference was significant at a p-value of 0.005. One patient (41.A1) was lost to follow-up after the initial operation. Apart from that patient, no tibial or femoral fractures required revision fixation for rotational malalignment for 2 years after surgery. Two tibial fractures (41.A3 and 41.C2) required hardware removal after fracture healing for hardware prominence. One tibial fracture (41.C1) required conversion to an IM tibial nail for nonunion of the diaphyseal extension of the fracture. One femoral fracture (33.A1) required revision plate fixation for coronal plane malalignment not rotational malalignment.

Table 1 Measured tibial rotational malalignment of 14 proximal tibia fractures stabilised with the L.I.S.S. plate system. Age

Gender

Side

Fracture type

Tibial rotation normal side (8)

Tibial rotation injured side (8)

Rotational deformity (8)

18 42 35 47 34 32 45 31 36 62 38 22 46 46

F M M M M F F M M M M M M M

Left Left Right Right Right Right Left Right Right Left Right Right Right Left

41.A3 41.C1 41.A3 41.C2 41.C3 41.A2 41.C3 41.A3 41.A2 41.C1 41.A2 41.C1 41.C2 41.C1

46.9 3.6 16.4 35.3 42.8 24.1 29.8 25.6 44.7 33.1 25.3 2.5 31.0 40.0

44.2 33.9 24.3 32.2 37.6 16.4 42.3 9.6 35.6 1.4 30.2 42.5 5.0 13.0

2.7 30.3 7.9 3.1 5.2 7.7 12.5 16.0 9.1 34.5 5.1 40.0 26.0 27.0

( ) Denotes internal rotation; mean rotational deformity 16.28; paired T-test (p-value) 0.656; % malrotated >108 7/14 (50%); malrotation range 2.7–35.48; Std Dev 12.8.

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Table 2 Measured femoral rotational malalignment of 13 distal femur fractures stabilised with the L.I.S.S. plate system. Age

Gender

Side

Fracture type

Femoral anteversion normal side (8)

19 50 78 65 68 73 78 27 46 70 55 50 46

M M F M F F F M F M F M M

Right Right Right Left Right Right Left Right Left Left Right Right Left

33.A1 33.A3 33.A1 33.C2 33.A1 33.A1 33.A1 33.A2 33.C1 33.A2 33.C2 33.A1 33.C1

12.7 12.7 11.0 6.6 28.2 11.8 18.5 15.1 8.7 7.4 2.9 23.0 1.0

Femoral anteversion injured side (8) 0.5 7.7 2.9 2.3 3.1 10.5 16.5 7.1 3.3 23.5 0.8 17.0 5.0

Rotational deformity (8) 13.2 5.0 13.9 4.3 31.3 22.3 2.0 8.0 5.4 30.9 3.7 6.0 4.0

( ) Denotes femoral retroversion; mean rotational deformity 11.58; paired T-test (p-value) 0.005; % malrotated >108 5/13 (38.5%); malrotation range 2.0–31.38; Std Dev 10.3.

Discussion Fractures around the knee are quite common and account for approximately 1–2% of all fractures. Typically, they occur bimodally, either as a result of high-energy trauma in the younger population or due to trivial falls in elderly people with osteoporotic bones. Distal femoral and proximal tibial periprosthetic fractures around total knee replacements are now a common phenomenon, with a reported incidence of 2–3%.31 Over the past 4 decades, there has been increased emphasis on open reduction and internal fixation of these fractures, to allow early pain-free mobilisation of the limb and the patient. Comparative studies have shown better union rates and functional outcome after internal fixation.3,24,34,35 However, open reduction of these metaphyseal fractures is associated with complications of up to 20%.32,47 Minimally invasive osteosynthesis is now a common technique, designed to provide stable internal fixation through a minimally invasive surgical technique. As the fracture site is not exposed directly, this technique conceptually counters all the disadvantages of direct open reduction. The ‘L.I.S.S.’ is a prototype of the minimally invasive systems. This implant system consists of anatomically precontoured plates and locking screws designed to provide angular stability at the plate–screw junction. The load transmission across the fracture occurs through the screw–plate junction without depending upon the frictional force between bone and plate. Tight apposition of plate to bone is not required, which spares the circumferential vascularity.8,9,33 While the principles of intra-articular fracture reduction and fixation are adhered to using the MIPO systems, fixation of the metaphyseal block to the shaft is done by indirect methods. Early results of the L.I.S.S. system are encouraging with reported high union rates and a much lower complication rate.7,9,10,19,20,30,36–39,43,48 However, restoration of limb alignment is critical at the time of any fracture stabilisation to produce optimal outcome. Malalignment of the femur or tibia in any plane can lead to abnormal load transmission across the adjacent joints and resultant shearing of the articular cartilage.12,18,22,25,42 Correct restoration of limb alignment, particularly rotational alignment, is technically difficult when resorting to indirect reduction techniques with the aid of intra-operative fluoroscopy. The only sure way to restore the normal anatomy is to ‘key in’ the various fracture fragments under direct vision. Depending on the degree of comminution of the metadiaphysis, even this can be extremely difficult. Draping of most of the limb and limited field of projection of the image intensifiers used for these closed procedures adds to the technical difficulty of accurate assessment of limb rotation intra-operatively.

CT scanning has become the gold standard for assessing limb rotational alignment.15,16,23,26,40 The test is accurate and has good inter- and intra-observer reliability and repeatability.28 Using CT, our study demonstrated a significantly higher incidence of femoral and tibial malrotation >10 of 38.5% and 50%, respectively, following L.I.S.S. plating. This incidence of malrotation is much higher than previously quoted in L.I.S.S. outcome studies to date.7,19,30,39,43 Femur fractures had a mean malrotation of 11.5, while tibias were malrotated by an average of 16.2. The most significant degree of malrotation was seen in the C1 and C2 tibial fractures and the A1 and A2 femur fractures, each showing >208. There did not appear to be a correlation between fracture severity and degree of malrotation in the femurs and tibias. In addition, postoperatively, there was no evidence to indicate clinically significant malrotation requiring revision surgery. There was also no evidence of a ‘learning curve’ in fracture reduction where one would expect higher degrees of malrotation in the fractures fixed earlier in the study than later. Of note, the type A femur fractures appeared to have a more significant degree of malrotation than the more comminuted type C fractures and the type C tibial fractures were more malrotated than the type A fractures. This seems counterintuitive and contradictory. Type A femur fractures are extra-articular whereas the type C fractures are intra-articular with a higher degree of comminution. Using intra-articular fracture reduction and fixation principles, open reduction and visualisation of the articular surface prior to fixation of the metaphyseal block to the diaphyseal segment would have allowed a wider anatomical view of the fracture. This wider anatomical view and dissection, compared with a standard minimally invasive approach without the need for articular reduction and fixation, may have allowed for a better assessment of the reduction in all planes. Furthermore, the more comminuted fractures may have responded to traction and ligamentotaxis in a more favourable manner, allowing the soft tissues to re-align the fracture fragments closer to their anatomic positions. Type A fractures with larger extra-articular fracture fragments can be more difficult to reduce with a minimally invasive approach depending strictly on ligamentotaxis, as the fracture fragments can sometimes get ‘caught up’ in the surrounding soft tissues and prevent accurate reduction. Regarding the tibial fractures, unfortunately, no conclusions can be drawn from this group as the difference between the mean measures of rotation was insignificant, indicating the group was underpowered. Three of the type A and none of the type C tibial fractures were grade II open fractures. Treating these fractures with irrigation, debridement and then fixation using the L.I.S.S. system may have contributed to the lesser degree of malrotation seen in this group. Also, the generally smaller soft-tissue envelope around the tibia,

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combined with the ability to use more of the extremity for judging alignment, may have made reduction of the type A fractures more successful. Intra-operative assessment of limb alignment can be extremely difficult, particularly because there can be a wide range of tibial rotation and femoral version between patients. Based on our study results, improved techniques to assess rotation intra-operatively need to be developed. Fluoroscopy provides some assistance, particularly with coronal and sagittal alignment, using antero-posterior (AP) and lateral images. However, the field of view is limited. Rotational alignment is the most difficult to assess. The other limb, if uninjured, is needed as a comparison to base rotational measurements upon. Previous studies using CT scans looking at uninjured lower limbs for rotation and length show an average side-to-side difference in rotation of only 3–48.40 Including the uninjured limb in the surgical preparation would benefit reduction assessment. Tornetta has described a technique of using a distal femoral traction pin and fluoroscopy of both normal and injured extremities to better judge rotation for femoral shaft fractures.41 This technique could only be used in extra-articular distal femoral fractures, if any. Protractor devices mounted on the fluoroscopy C-arm units as well as anatomic landmark computer profiling have also been described as techniques to assess limb rotation, and these could be adapted to assess tibial torsion and femoral version.6,14 However, malrotation of up to 158 is still noted with these methods. Preoperative imaging of the uninjured extremity to evaluate anatomic rotation may provide useful information to the surgeon when performing fracture reduction and fixation on the contralateral extremity. Availability of resources, costs, radiation exposure and the inconvenience of imaging an injured patient multiple times make this option less attractive. To date, no convenient and reliable method of assessing intra-operative lower limb rotation has been developed and used consistently. This is an area for further work and development to improve results in lower limb fracture management. Our study had several limitations and shortcomings. A larger patient population from multiple centres would make the results more generalisable and relevant. No consistent record was kept of adjuncts to fracture reduction and fixation used for each case. Manual traction, traction boot, pins or temporary K-wire fixation are a few examples of adjuncts that may influence quality of reduction. Although it can be assumed that the clinical assessment of limb rotation was deemed acceptable intra-operatively, this study would have been stronger if we would have correlated clinical rotational assessment to postoperative CT assessment. Despite the fact that none of our patients required revision of their fracture fixation for reasons of clinical malrotation, clinical correlation was not made between the malrotated limbs and postoperative patient satisfaction using any outcome scores. Although the purpose of this study was mainly to assess limb rotation radiographically, clinical correlation and functional limitations related to the degree of malrotation would highlight the importance of accurate rotational alignment. Finally, the subpopulation of tibia fractures was underpowered. Conclusion Tibial torsion and femoral version rotational malalignment is under-appreciated in the literature when distal femoral and proximal tibial fractures are assessed clinically by an examining surgeon. CT scanning identified rotational malalignment in 38.5% of distal femur fractures and 50% of proximal tibial fractures in our study. Certain injury patterns appear to be more prone to malreduction with indirect methods than others. Work needs to be done to develop a consistent, reliable and convenient method of

assessing intra-operative rotational fracture alignment and reduction. Long-term outcome studies looking at malrotated limbs and the development of corresponding joint disease should be performed. Conflicts of interest All authors disclose that they have no conflict of interests that could inappropriately influence this work. This study was selffunded. Funding source Self-funded. Acknowledgement We wish to thank Dr. James Powell for the inclusion of patients in this study. References 1. Alho A, Ekeland A, Stromsoe K, et al. Locked intramedullary nailing for displaced tibial shaft fractures. J Bone Joint Surg Br 1990;72(September (5)):805–9. 2. Alho A, Stromsoe K, Ekeland A. Locked intramedullary nailing of femoral shaft 420 fractures. J Trauma 1991;31(January (1)):49–59. 3. Barei DP, Nork SE, Mills WJ, et al. Complications associated with internal fixation of high-energy bicondylar tibial plateau fractures utilizing a twoincision technique. J Orthop Trauma 2004;18(November–December (10)): 649–57. 4. Blachut PA, O’Brien PJ, Meek RN, et al. Interlocking intramedullary nailing with and without reaming for the treatment of closed fractures of the tibial shaft. A prospective, randomized study. J Bone Joint Surg Am 1997;79(May (5)):640–6. 5. Braten M, Terjesen T, Rossvoll I. Torsional deformity after intramedullary nailing of femoral shaft fractures. Measurement of anteversion angles in 110 patients. J Bone Joint Surg Br 1993;75(September (5)):799–803. 6. Clementz BG. Assessment of tibial torsion and rotational deformity with a new 499 fluoroscopic technique. Clin Orthop Relat Res 1989;245(August):199–209. 7. Cole PA, Zlowodzki M, Kregor PJ. Treatment of proximal tibia fractures using the less 455 invasive stabilization system: surgical experience and early clinical results in 77 fractures. J Orthop Trauma 2004;18(September (8)):528–35. 8. Farouk O, Krettek C, Miclau T, et al. Effects of percutaneous and conventional plating techniques on the blood supply to the femur. Arch Orthop Trauma Surg 1998;117(8):438–93. 9. Frigg R, Appenzeller A, Christensen R, et al. The development of the distal femur Less Invasive Stabilization System (LISS). Injury 2001;32 Suppl 3(December):SC24–31. Review. 10. Goesling T, Frenk A, Appenzeller A, et al. LISS PLT: design, mechanical and biomechanical characteristics. Injury 2003;1 Suppl(August (34)):A11–5. 11. Gregory P, Sanders R. The treatment of closed, unstable tibial shaft fractures with unreamed interlocking nails. Clin Orthop Relat Res 1995;315(June):48–55. 12. Gugenheim JJ, Probe RA, Brinker MR. J Orthop Trauma. The effects of femoral shaft malrotation on lower extremity anatomy 2004;18(November–December (10)):658–64. 13. Jaarsma RL, Pakvis DF, Verdonschott N, et al. Rotational malalignment after intramedullary nailing of femoral fractures. J Orthop Trauma 2004;18(August (7)):403–9. 14. Jaarsma RL, Verdonschot N, van der Venne R, et al. Avoiding rotational malalignment after fractures of the femur by using the profile of the lesser trochanter: an in vitro study. Arch Orthop Trauma Surg 2005;125(April (3)):184–7. 15. Jakob RP, Haertel M, Stussi E. Tibial torsion calculated by computerised tomography and compared to other methods of measurement. J Bone Joint Surg Br 1980;62–463(May (B2)):238–42. 16. Jend HH, Heller M, Dallek M, et al. Measurement of tibial torsion by computer tomography. Acta Radiol Diagn (Stockh) 1981;22(3A):271–6. 17. Johner R, Wruhs O. Classification of tibial shaft fractures and correlation with results 472 after rigid internal fixation. Clin Orthop Relat Res 1983;178(September):7–25. 18. Kettelkamp DB, Hillberry BM, Murrish DE, et al. Degenerative arthritis of the knee secondary to fracture malunion. Clin Orthop Relat Res 1988;234(September):159–69. 19. Kregor PJ, Stannard J, Zlowodzki M, et al. 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(September (8)): 509–20. 20. Markmiller M, Konrad G, Sudkamp N. Femur-LISS and distal femoral nail for fixation of distal femoral fractures: are there differences in outcome and complications? Clin Orthop Relat Res 2004;426(September):252–7. 21. McKee MD, Schemitsch EH, Waddell JP, et al. A prospective, randomized clinical trial comparing tibial nailing using fracture table traction versus manual traction. J Orthop Trauma 1999;13(September–October (7)):463–9.

R. Buckley et al. / Injury, Int. J. Care Injured 42 (2011) 194–199 22. Milner SA, Davies TRC, Muir KR, et al. Long-term outcome after tibial shaft fracture: is malunion important? J Bone Joint Surg Am 2002;84–A(June (6)):971–80. 23. Murphy SB, Simon SR, Kijewski PK, et al. Femoral anteversion. J Bone Joint Surg Am 1987;69(October (8)):1169–76. 24. Neer CS, Grantham SA, Shelton ML. Supracondylar fracture of the adult femur. A study of one hundred and ten cases. J Bone Joint Surg Am 1967;49(June (4)):591. 25. Netz P, Olsson E, Ringertz H, et al. Functional restitution after lower leg fractures. A long-term follow-up. Arch Orthop Trauma Surg 1991;110(5): 238–41. 26. Pfeifer T, Mahlo R, Franzreb M, et al. Computed tomography in the determination of leg geometry. In Vivo 1995;9(May–June (3)):257–61. 27. Pintore E, Maffulli N, Petricciuolo F. Interlocking nailing for fractures of the femur and tibia. Injury 1992;23(6):381–6. 28. Puloski S, Romano C, Buckley R, et al. Rotational malalignment of the tibia following reamed intramedullary nail fixation. J Orthop Trauma 2004;18(August (7)):397–402. 29. Ricci WM, Bellabarba C, Lewis R, et al. Angular malalignment after intramedullary nailing of femoral shaft fractures. J Orthop Trauma 2001;15(February (2)):90–5. 30. Ricci WM, Rudzki JR, Borrelli Jr J. Treatment of complex proximal tibia fractures with the less invasive skeletal stabilization system. J Orthop Trauma 2004;18(September (8)):521–7. 31. Rorabeck CH, Taylor JW. Periprosthetic fractures of the femur complicating total knee arthroplasty. Orthop Clin North Am 1999;30(April (2)):265–77. Review. 32. Sanders R, Regazzoni P, Ruedi TP. Treatment of supracondylar-intracondylar fractures of the femur using the dynamic condylar screw. J Orthop Trauma 1989;3(3):214–22. 33. Schandelmaier P, Partenheimer A, Koenemann B, et al. Distal femoral fractures and LISS stabilization. Injury 2001;32 Suppl 3(December):SC55–63. Review. 34. Schatzker J, Horne G, Waddell J. The Toronto experience with the supracondylar fracture of the femur, 1966–72. Injury 1974;6(November (2)):113–28. 35. Schatzker J, McBroom R, Bruce D. The tibial plateau fracture. The Toronto experience 1968–1975. Clin Orthop Relat Res 1979;138(January–February):94–104.

199

36. Schutz M, Kaab MJ, Haas N. Stabilization of proximal tibial fractures with the LIS366 System: early clinical experience in Berlin. Injury 2003;34 Suppl 1(August):A30–5. 37. Schutz M, Muller M, Regazzoni P, et al. Use of the less invasive stabilization system (LISS) in patients with distal femoral (AO33) fractures: a prospective multicenter study. Arch Orthop Trauma Surg 2005;125(Mar (2)):102–8. Epub 2005 Feb 2. 38. Stannard JP, Wilson TC, Volgas DA, et al. Fracture stabilization of proximal tibial fractures with the proximal tibial LISS: early experience in Birmingham, Alabama (USA). Injury 2003;34 Suppl 1(August):A36–42. 39. Stannard J, Wilson TC, Volgas DA, et al. The less invasive stabilization system in the treatment of complex fractures of the tibial plateau: short-term results. J Orthop Trauma 2004;18(September (8)):552–8. 40. Strecker W, Keppler P, Gebhard F, et al. Length and torsion of the lower limb. J Bone Joint Surg Br 1997;79(November (6)):1019–23. 41. Tornetta 3rd P, Ritz G, Kantor A. Femoral torsion after interlocked nailing of unstable femoral fractures. J Trauma 1995;38(February (2)):213–9. 42. van der Schoot DKE, Den Outer AJ, Bode PJ, et al. Degenerative changes at the knee and ankle related to malunion of tibial fractures. 15-year follow-up of 88 patients. J Bone Joint Surg Br 1996;78(September (5)):722–5. 43. Weight M, Collinge C. Early results of the less invasive stabilization system for mechanically unstable fractures of the distal femur (AO/OTA types A2, A3, C2, and C3). J Orthop Trauma 2004;18(September (8)):503–8. 44. Williams J, Gibbons M, Trundle H, et al. Complications of nailing in closed tibial fractures. J Orthop Trauma 1995;9(6):476–81. 45. Wiss DA, Fleming CH, Matta JM, et al. Comminuted and rotationally unstable fractures of the femur treated with an interlocking nail. Clin Orthop Relat Res 1986;212(November):35–47. 46. Wiss DA, Stetson WB. Unstable fractures of the tibia treated with a reamed intramedullary interlocking nail. Clin Orthop Relat Res 1995;315(June): 56–63. 47. Young MJ, Barrack RL. Complications of internal fixation of tibial plateau fractures. Orthop Rev 1994;23(February (2)):149–54. 48. Zlowodzki M, Williamson S, Cole PA, et al. 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;18(September (8)):494–502.