- Email: [email protected]
Does it really spin? Intra-medullary nailing of segmental tibial fractures—A cadaveric study
Injury, Int. J. Care Injured 46 (2015) 643–648
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Does it really spin? Intra-medullary nailing of segmental tibial fractures—A cadaveric study Mateen H. Arastu a, Brendan Sheehan b, Elizabeth Oddone Paolucci c,d, Richard E. Buckley b,* a
University Hospital Coventry and Warwickshire, Coventry, UK Division of Orthopaedic Trauma Surgery, Foothills Medical Centre, Calgary, Alberta, Canada Department of Surgery, Faculty of Medicine, University of Calgary, Alberta, Canada d Department of Community Health Sciences, Faculty of Medicine, University of Calgary, Alberta, Canada b c
A R T I C L E I N F O
A B S T R A C T
Article history: Accepted 11 January 2015
This study aims to quantify the effect of intra-medullary reaming on rotational displacement of both long diaphyseal segmental tibial fractures (Melis Type III) and short (Melis Type IV) in a cadaveric model with differing degrees of soft tissue stripping. Eighteen fresh-frozen cadaveric specimens (9 matched pairs), median age at death was 85 years (68– 92) were used to perform a standardized reaming procedure for an intra-medullary tibial nail and the rotational displacement of the segmental fracture fragment (long and short diaphyseal fractures) was recorded. Rotational displacement was recorded using a goniometer and K-wires positioned in the proximal, segmental and distal fracture fragments. Type III fractures rotate more than Type IV fractures (p < 0.0001). In Type III fractures reaming to fit with 0%, 50% and 100% soft tissue stripping resulted in rotational displacement of 11.7 SD 12), 13 (SD 16.5) and 307.3 (SD 118.1) degrees respectively. In Type IV fractures reaming to fit with 0%, 50% and 100% soft tissue stripping resulted in rotational displacement of 8.5 (SD 5.5), 12.7 (SD 9.9) and 135.3 (SD 147.1) degrees respectively. The use of a pointed reduction clamp or unicortical plate eliminated rotational displacement. Reaming is a major risk factor for rotational displacement of segmental tibial fractures irrespective of the degree of soft tissue stripping. Long diaphyseal segmental fractures rotate more than shorter segmental fractures. We recommend always clamping the fracture during reaming to avoid rotational displacement. ß 2015 Elsevier Ltd. All rights reserved.
Keywords: Tibia fracture Segmental Intra-medullary reaming Soft tissue stripping
Introduction Segmental tibial fractures are rare and are often the result of high-energy trauma with significant soft tissue stripping at the site of injury. A classification of segmental tibial fractures was proposed by Melis et al. which included types I–IV (Fig. 1) [1]. Minimally invasive osteosynthesis techniques are paramount in order to preserve the soft tissue envelope around a fracture in order to maintain blood supply to promote fracture union and avoid complications [2]. Treatment of these difficult fractures remains controversial and includes non-operative management,
* Corresponding author at: Division of Orthopaedic Trauma Surgery, Foothills Medical Centre, 0490 Ground Floor, McCaig Tower, 3134 Hospital Drive NW, Calgary, Alberta, Canada T2N 5A1. Tel.: +1 403 944 8371; fax: +1 403 270 8004. E-mail address: [email protected] (R.E. Buckley). http://dx.doi.org/10.1016/j.injury.2015.01.014 0020–1383/ß 2015 Elsevier Ltd. All rights reserved.
open reduction and internal fixation, external fixation and intramedullary nailing [1,3–10]. The associated complications with this injury pattern are non-union, delayed union, malunion, osteonecrosis and infection [1,11,12]. Techniques have been described in order to maintain the reduction of the fracture prior to intra-medullary reaming which include the use of a pointed reduction clamp to hold the segmental component of the fracture, temporary unicortical plating or using a Farabeuf clamp [1,11,13,14]. Rotational displacement is undesirable as it potentially will strip the remaining soft tissue vascular attachments to the fracture fragment and result in delayed healing, infection, malunion or non-union. However, there is no scientific evidence in the literature that undesirable rotational displacement of segmental tibial fractures when treated with intra-medullary nailing is a direct consequence of reaming the fracture. This study aims to quantify the effect of intra-medullary reaming on rotational displacement of both long
644
M.H. Arastu et al. / Injury, Int. J. Care Injured 46 (2015) 643–648
Fig. 1. Melis segmental tibia fracture classification. Type I – fractures in the proximal and middle third. Type II – fractures in the middle and distal third. Type III – fractures in the proximal and distal third creating a long central fracture fragment. Type IV – fractures in the middle third creating a short central fracture fragment.
diaphyseal segmental tibial fractures (Melis Type III) and short (Melis Type IV) in a cadaveric model with differing degrees of soft tissue stripping. Materials and methods Institutional Review Board approval was obtained to perform the study. Eighteen fresh-frozen lower limb cadaveric specimens (9 matched pairs) were obtained from Department of Anatomy, University of Calgary. One specimen was excluded secondary to pathologic bone and one specimen was used as a trial to optimize the methodology and time points for measuring rotational displacement. A total of 16 specimens were included in our final results. The median age of the cadaveric specimens was 85 years (68–92). There were 12 male specimens and 4 female specimens. The mean intramedullary canal size for the specimens at ream to fit was 11.8 mm. The cadaveric specimen was secured with a clamp around the femur and 1.6 mm unicortical K-wires were inserted into the tibial tuberosity, midportion of the segmental fracture fragment and mid malleolar point in a parallel fashion using a ruler (Fig. 2A and B). Small vertical stab incisions were used and an oscillating saw (1.5 cm blade) used to create a transverse segmental tibia fracture, either 2.5 cm (Melis Type IV fracture) or 12 cm (Melis Type III fracture) in length with the midportion of the tibia (isthmus) at the centre of the fracture fragment (measured equidistant from the tibial plafond and plateau). This process was repeated to create a same level segmental fibula fracture either 3.5 cm or 12 cm in length. With the fracture reduced, all three K-wires were parallel. A total of 8 Type III and 8 Type IV fractures were used.
Soft tissue stripping was performed sharply with a scalpel blade. In the specimens classified as 0% soft tissue stripping access to the segmental fracture to use the oscillating saw was made by 2 cm vertical incisions over the antero-medial border of the tibia; 50% soft tissue stripping all of the soft tissue attachments were removed from the antero-lateral border of the tibia and interosseous membrane was left intact. When 100% soft tissue stripping was performed, all of the antero-lateral and posterior tissues including the inter-osseous membrane were dissected from the segmental tibial fragment. Linear circumferential incisions were used to create tracts for the K-wires to rotate freely as during the methodology optimization K-wires were not fully rotating due to soft tissue impedance (Fig. 3). If a greater degree of rotational displacement occurred then the K-wire in the intermediate fragment was removed in order to visualize this and prevent impedance of rotation. A medial parapatellar approach was used to perform a standardized intra-medullary reaming technique with new reamers (Expert Tibial Nail, Synthes, Mississauga, ON, Canada) starting with an 8.5 mm end-cutting reamer then increased sequentially in 0.5 mm increments until the canal had been over reamed by one reamer size. The size at which ream to fit was achieved was noted for each specimen when cortical chatter was first achieved. As the tibia was reamed by one investigator, a second maintained a manual reduction of the fracture fragment using axial load. The degree of axial load applied was judged by the investigator in order to maintain an adequate fracture reduction under direct visualization as may occur during freehand intra-medullary tibial nail. The fracture fragment was anatomically reduced under direct
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Fig. 2. (A, B) The cadaveric specimen was secured in a clamp attached to the distal femur and unicortical K-wires inserted in a parallel fashion in the tibial tuberosity, segmental fracture fragment and mid malleolar point in order to measure the rotational displacement with a goniometer.
visualization prior to each subsequent reamer insertion. Parallelism of the K-wires was used as an additional guide to judge fracture reduction. Rotational displacement of the tibial segment was measured for each reamer size with a goniometer between the proximal and segmental fracture K-wires. For each reamer size, displacement was recorded at 3 time points, initially when the reamer entered the fracture fragment at maximal rotational displacement; when the reamer passed from the segmental fracture into the distal tibia and the final rotational displacement of the tibial segment when the reamer was withdrawn. No intramedullary tibial nails were used in this study as the process of reaming causing rotation of segmental fracture fragments was being investigated. Four specimens (Melis Type III (n = 2), Melis Type IV (n = 2)) were reamed with 0%, 50% and 100% soft tissue stripping respectively. Two specimens (Melis Type III (n = 1), Melis Type IV (n = 1)), with 100% soft tissue stripping were plated with a 4 hole one third tubular small fragment plate on the posteromedial tibial border at the
level of the proximal fracture line using unicortical non locked 3.5 mm screws (2 proximal and 2 distal to fracture) prior to reaming in order to prevent rotational displacement of the fracture. Two specimens (Melis Type III (n = 1), Melis Type IV (n = 1)), each with 100% soft tissue stripping, were reamed with the fracture fragment held in place with a pointed reduction clamp (Fig. 4). Statistical analysis Statistical analysis was performed using IBM SPSS Statistics v19 (IBM, New York, New York, USA). An Independent Samples Mann– Whitney U test was computed on degrees of rotational displacement and reamer size by soft tissue stripping. A Univariate General Linear Model Analysis was used to compare fracture type and percentage soft tissue stripping by degrees of rotational displacement. A Bonferroni post hoc test was then conducted to see if there was a statistical difference between percentage soft tissue stripping groups. The level of significance was set at p < 0.05.
Fig. 3. (A, B) Soft tissue impedance prevented free rotation of the K-wire in the segmental fracture fragment during intra-medullary reaming (A) and creating a linear soft tissue tract allowed free rotation on order to measure rotation accurately (B).
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Fig. 4. The prevention of rotational displacement is demonstrated using a pointed reduction clamp during intra-medullary reaming.
Results The mean rotational displacement across all fracture types and reamer sizes for the 0%, 50% and 100% soft tissue stripping groups was 10.4 (SD 9.9), 12.8 (SD 13.7) and 208.1 (SD 158.7) degrees respectively. The difference in rotation between the 0% and 100% group, as well as the 50% and 100% group were statistically significant for both Type III and Type IV fractures (p < 0.0001). The increasing rotational displacement with increasing soft tissue stripping is shown in Fig. 5. Table 1 shows the mean rotational displacement for differing amounts of soft tissue stripping for both Type III and IV fractures. There was a significant difference in terms of mean rotational displacement between fracture types, with Type III fractures showing more rotation than Type IV fractures at 100% soft tissue stripping, as shown in Fig. 4 (p < 0.0001). Table 2 shows the mean rotational displacement of the segmental fracture fragment with increasing reamer sizes for all percentages of soft tissue stripping as well as individually for 0%, 50% and 100% stripping. Within each group there was a statistically significant increase in the degree of rotational displacement as reamer size increased, with the maximal rotation occurring when the tibia was over reamed by one reamer size (p < 0.0001). At 100% soft tissue stripping, when the tibia was reamed to fit, the segmental fragment spun freely (>360 degrees). On removal of the reamer following the initial rotational displacement there was no recoil of the displaced fracture fragment back to a less rotationally displaced position in any of the specimens investigated. The control specimens (unicortical plate (n = 2) and clamp (n = 2)) maintaining fracture reduction during reaming showed no rotational displacement of the segmental fracture fragment at 100% soft tissue stripping. Discussion Segmental tibia fractures are high-energy injuries with extensive soft tissue stripping and risk of complications is significant [1,3,4,12,15,16]. To the best of our knowledge this is the first study to show that segmental tibia fractures rotate secondary to intramedullary reaming. The mean rotational displacement for both Melis Type III and IV fractures was 10.4, 12.8 and 208.1 degrees for 0, 50 and 100% soft tissue stripping respectively. This degree of rotational displacement may further jeopardize remaining vascular attachments to the fracture fragment and predispose the patient to delayed healing, infection, mal-union or non-union. Long segmental fractures (12.5 cm) rotated to a greater degree than short (2.5 cm) fractures in this study and were statistically
Fig. 5. (A, B) The degree of rotational displacement with 0%, 50% and 100% soft tissue stripping with increasing reamer size for Type III (12.5 cm segmental fracture fragment) (A) and Type IV (2.5 cm segmental fracture fragment) (B). Not ream to fit defined by reamer sizes where no cortical chatter present; ream to fit defined by first cortical chatter and over ream defined by reaming beyond first cortical chatter by 1 mm.
significant. The reason for this may be that a longer segmental fracture fragment will be the result of a higher energy injury and as a result have more extensive soft tissue stripping. In addition to this the longer segmental fracture fragment will have a longer Table 1 Mean rotational displacement of segmental fracture fragment in Type III and IV fractures with differing amounts of soft tissue stripping. Melis fracture type
Soft tissue stripping (%)
Mean rotational displacement (degrees) (SD)
p-Value
Type III
0 50 100 0 50 100 0 50 100
11.67 12.95 307.27 8.53 12.63 135.33 10.37 12.80 208.08
<0.0001
Type IV
Type III and IV
(12.0) (16.5) (118.1) (5.5) (9.9) (147.1) (9.9) (13.7) (158.7)
<0.0001
M.H. Arastu et al. / Injury, Int. J. Care Injured 46 (2015) 643–648 Table 2 (A, B) Mean rotational displacement of segmental fracture fragment with different reamer sizes (A – Type III and B – Type IV fractures. End cutting reamer = 8.5 mm; ream to fit defined by first cortical chatter and over ream defined by reaming beyond first cortical chatter by 1 mm. Soft tissue stripping (%) A 0
50
100
All
B 0
50
100
All
Reamer size
Mean rotational displacement (degrees) (SD)
p-Value
8.5 mm Ream to fit Over ream 8.5 mm Ream to fit Over ream 8.5 mm Ream to fit Over ream 8.5 mm Ream to fit Over ream
2.5 (3.5) 25 (7.1) 32.5 (3.5) 0 (0) 37.5 (10.6) 42.5 (3.5) 200 (226.3) 360.00 (0) 360 (0) 67.5 (144.1) 140.8 (169.9) 145 (166.6)
<0.0001
8.5 mm Ream to fit Over ream 8.5 mm Ream to fit Over ream 8.5 mm Ream to fit Over ream 8.5 mm Ream to fit Over ream
7.5 (3.5) 12.5 (3.5) 20 (0) 7.5 (3.5) 25 (7.1) 32.5 (3.5) 15 (21.2) 360.00 (0) 360 (0) 10 (10.5) 132.5 (176.3) 137.5(172.4)
<0.0001
isthmic region of bone in contact with the reamer and torsional displacement as a result would be more likely. In this study there was a statistically significant increase in the degree of rotational displacement as reamer size increased in both Type III and IV fractures with more soft tissue stripping, with the maximal rotation occurring when the tibia was over reamed by one reamer size. At 100% soft tissue stripping, when the tibia was reamed to fit, the segmental fragment spun freely (>360 degrees). Kakar and Tornetta [16] published a series of 62 consecutive patients with closed and open segmental tibia fractures (AO-OTA 42-C2) treated with unreamed tibial nails and concluded that this technique was associated with high union rates (91%), few complications, and limited indications for secondary procedures in the management of segmental tibia fractures. Unreamed nails were thought to be less likely to disturb the fracture fragment’s precarious blood supply. However, the use of small diameter nails may result in an increased incidence of mal-unions as they may not provide adequate stability acutely or during the healing phase [17]. Woll and Duwelius [11] reported an incidence of 29% of malunions in their series of segmental tibia fractures treated with unreamed nails. Singer and Kellam [17] reported 49% of fractures were malunited, particularly in the proximal third of the diaphysis. Due to the prolonged healing time for segmental tibia fractures and the risk of mal-union and implant failure a carefully performed reamed tibial nail may be more advantageous than an unreamed nail but prevention of rotational displacement is paramount. Melis et al. described in 1981 that during blind reaming, any undesirable rotation of the intermediate fragment was controlled manually and rotation was undesirable because it tends to tear the residual vascular connections of the fragments and therefore, cautious progressive reaming was required but did not explain these statements any further [1]. Giannoudis et al. also stated that the use of a large pointed reduction clamp was found to be very
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useful to reduce and stabilize the segmental fracture to prevent spinning and mal-alignment during reaming and nail insertion [4]. The use of a Farabeuf [13] clamp or unicortical plate application [18] has been described to maintain the reduction of segmental tibia fractures but not specifically to prevent undesirable rotation of the intermediary segment. In this study unicortical plating of the proximal fracture and the use of a large pointed reduction clamp prevented any rotational displacement in Type III and IV fractures with 100% soft tissue stripping. However, the use of a plate to prevent rotation in a fracture that has a compromised soft tissue envelope may not be the optimal method to stabilize the fracture during reaming. The use of this technique in this study was to provide another control group in addition to fractures stabilized with a percutaneous reduction clamp. The use of the pointed reduction clamp should not significantly strip any further soft tissue from the intermediary fracture segment and therefore may be more advantageous when compared to unicortical plating. The limitations of this study were that fresh frozen cadaveric tissue was used and the sample size was small. The methodology used has compromised the soft tissue envelope even in the group with 0% soft tissue stripping and must be taken into account and an over estimation of rotation is a possibility. In addition, transverse osteotomies with no interdigitation of fracture fragments to resist rotation is a less likely clinical scenario and may lead to an over estimation of the effect of soft tissue stripping on fragment rotation. No radiographic assessment of fractures was performed during the reaming procedure but the fracture lines were directly visible through the incisions used to create the osteotomies and as a result reduction of the fracture during reaming was accurate. Crude assessment of rotation using a goniometer was performed using K-wires to determine displacement that is subject to human error but during intra-medullary nail fixation, assessment of rotation based upon intra-operative radiographic images is often very difficult. The point at which first cortical chatter was noted is subjective and may have varied depending on the cortical bone density, which would have been compromised given the age of the cadaveric specimens. Intra-medullary nail fixation of segmental tibia fractures is technically demanding. The surgical technique is critical in order to preserve the residual soft tissue envelope and vascular supply to significantly damaged tissue and obtain an accurate reduction of the fracture. Reaming to fit is a significant risk factor for causing rotational displacement of the intermediate fragment but the potential biomechanical benefits of a larger intra-medullary nail are appealing. Over reaming must be avoided. The routine use of a pointed reduction clamp for both long and short diaphyseal segmental fractures is recommended which can prevent any undesirable rotation. The consideration of unicortical plating of the proximal portion of the segmental fracture can also be performed but this does risk more extensive soft tissue stripping of the fracture fragment. Financial disclosure The authors report no financial disclosures related to the manuscript. Conflict of interest None declared. Acknowledgements We would like to thank Mr Nolan Brown (DePuy Synthes, Canada) for the provision of the intra-medullary reamers for this study.
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References [1] Melis GC, Sotgiu F, Lepori M, Guido P. Intramedullary nailing in segmental tibial fractures. J Bone Joint Surg Am Vol 1981;63:1310–8. [2] Farouk O, Krettek C, Miclau T, Schandelmaier P, Guy P, Tscherne H. Minimally invasive plate osteosynthesis and vascularity: preliminary results of a cadaver injection study. Injury 1997;28(Suppl. 1):A7–12. [3] Ajay M. Segmental tibial fractures: an assessment of procedures in 27 cases. Injury 2004;35:834. [4] Giannoudis PV, Hinsche AF, Cohen A, Macdonald DA, Matthews SJ, Smith RM. Segmental tibial fractures: an assessment of procedures in 27 cases. Injury 2003;34:756–62. [5] Siebenrock KA, Schillig B, Jakob RP. Treatment of complex tibial shaft fractures. Arguments for early secondary intramedullary nailing. Clin Orthop Relat Res 1993;269–74. [6] Huang CK, Chen WM, Chen TH, Lo WH. Segmental tibial fractures treated with interlocking nails. A retrospective study of 33 cases. Acta Orthop Scand 1997;68:563–6. [7] Beardi J, Hessmann M, Hansen M, Rommens PM. Operative treatment of tibial shaft fractures: a comparison of different methods of primary stabilisation. Arch Orthop Trauma Surg 2008;128:709–15. [8] Giotakis N, Panchani SK, Narayan B, Larkin JJ, Al Maskari S, Nayagam S. Segmental fractures of the tibia treated by circular external fixation. J Bone Joint Surg Br 2010;92-B:687–92. [9] Ma CH, Tu YK, Yeh JH, Yang SC, Wu CH. Using external and internal locking plates in a two-stage protocol for treatment of segmental tibial fractures. J Trauma 2011;71:614–9.
[10] Sarmiento A, Gersten L, Sobol P, Shankwiler J, Vangsness C. Tibial shaft fractures treated with functional braces. Experience with 780 fractures. J Bone Joint Surg Br 1989;71-B:602–9. [11] Woll TS, Duwelius PJ. The segmental tibial fracture. Clin Orthop Relat Res 1992;204–7. [12] Rommens PM, Coosemans W, Broos PL. The difficult healing of segmental fractures of the tibial shaft. Arch Orthop Trauma Surg 1989;108: 238–42. [13] Robertson A, Giannoudis PV, Matthews SJ. Maintaining reduction during unreamed nailing of a segmental tibial fracture: the use of a Farabeuf clamp. Injury 2003;34:389–91. [14] Matthews DE, McGuire R, Freeland AE. Anterior unicortical buttress plating in conjunction with an unreamed interlocking intramedullary nail for treatment of very proximal tibial diaphyseal fractures. Orthopedics 1997;20: 647–8. [15] Giotakis N, Panchani SK, Narayan B, Larkin JJ, Al Maskari S, Nayagam S. Segmental fractures of the tibia treated by circular external fixation. J Bone Joint Surg Br 2010;92:687–92. [16] Kakar S, Tornetta 3rd P. Segmental tibia fractures: a prospective evaluation. Clin Orthop Relat Res 2007;460:196–201. [17] Singer RW, Kellam JF. Open tibial diaphyseal fractures. Results of unreamed locked intramedullary nailing. Clin Orthop Relat Res 1995;114–8. [18] Kim KC, Lee JK, Hwang DS, Yang JY, Kim YM. Provisional unicortical plating with reamed intramedullary nailing in segmental tibial fractures involving the high proximal metaphysis. Orthopedics 2007;30:189–92.
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Does it really spin? Intra-medullary nailing of segmental tibial fractures—A cadaveric study Mateen H. Arastu a, Brendan Sheehan b, Elizabeth Oddone Paolucci c,d, Richard E. Buckley b,* a
University Hospital Coventry and Warwickshire, Coventry, UK Division of Orthopaedic Trauma Surgery, Foothills Medical Centre, Calgary, Alberta, Canada Department of Surgery, Faculty of Medicine, University of Calgary, Alberta, Canada d Department of Community Health Sciences, Faculty of Medicine, University of Calgary, Alberta, Canada b c
A R T I C L E I N F O
A B S T R A C T
Article history: Accepted 11 January 2015
This study aims to quantify the effect of intra-medullary reaming on rotational displacement of both long diaphyseal segmental tibial fractures (Melis Type III) and short (Melis Type IV) in a cadaveric model with differing degrees of soft tissue stripping. Eighteen fresh-frozen cadaveric specimens (9 matched pairs), median age at death was 85 years (68– 92) were used to perform a standardized reaming procedure for an intra-medullary tibial nail and the rotational displacement of the segmental fracture fragment (long and short diaphyseal fractures) was recorded. Rotational displacement was recorded using a goniometer and K-wires positioned in the proximal, segmental and distal fracture fragments. Type III fractures rotate more than Type IV fractures (p < 0.0001). In Type III fractures reaming to fit with 0%, 50% and 100% soft tissue stripping resulted in rotational displacement of 11.7 SD 12), 13 (SD 16.5) and 307.3 (SD 118.1) degrees respectively. In Type IV fractures reaming to fit with 0%, 50% and 100% soft tissue stripping resulted in rotational displacement of 8.5 (SD 5.5), 12.7 (SD 9.9) and 135.3 (SD 147.1) degrees respectively. The use of a pointed reduction clamp or unicortical plate eliminated rotational displacement. Reaming is a major risk factor for rotational displacement of segmental tibial fractures irrespective of the degree of soft tissue stripping. Long diaphyseal segmental fractures rotate more than shorter segmental fractures. We recommend always clamping the fracture during reaming to avoid rotational displacement. ß 2015 Elsevier Ltd. All rights reserved.
Keywords: Tibia fracture Segmental Intra-medullary reaming Soft tissue stripping
Introduction Segmental tibial fractures are rare and are often the result of high-energy trauma with significant soft tissue stripping at the site of injury. A classification of segmental tibial fractures was proposed by Melis et al. which included types I–IV (Fig. 1) [1]. Minimally invasive osteosynthesis techniques are paramount in order to preserve the soft tissue envelope around a fracture in order to maintain blood supply to promote fracture union and avoid complications [2]. Treatment of these difficult fractures remains controversial and includes non-operative management,
* Corresponding author at: Division of Orthopaedic Trauma Surgery, Foothills Medical Centre, 0490 Ground Floor, McCaig Tower, 3134 Hospital Drive NW, Calgary, Alberta, Canada T2N 5A1. Tel.: +1 403 944 8371; fax: +1 403 270 8004. E-mail address: [email protected] (R.E. Buckley). http://dx.doi.org/10.1016/j.injury.2015.01.014 0020–1383/ß 2015 Elsevier Ltd. All rights reserved.
open reduction and internal fixation, external fixation and intramedullary nailing [1,3–10]. The associated complications with this injury pattern are non-union, delayed union, malunion, osteonecrosis and infection [1,11,12]. Techniques have been described in order to maintain the reduction of the fracture prior to intra-medullary reaming which include the use of a pointed reduction clamp to hold the segmental component of the fracture, temporary unicortical plating or using a Farabeuf clamp [1,11,13,14]. Rotational displacement is undesirable as it potentially will strip the remaining soft tissue vascular attachments to the fracture fragment and result in delayed healing, infection, malunion or non-union. However, there is no scientific evidence in the literature that undesirable rotational displacement of segmental tibial fractures when treated with intra-medullary nailing is a direct consequence of reaming the fracture. This study aims to quantify the effect of intra-medullary reaming on rotational displacement of both long
644
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Fig. 1. Melis segmental tibia fracture classification. Type I – fractures in the proximal and middle third. Type II – fractures in the middle and distal third. Type III – fractures in the proximal and distal third creating a long central fracture fragment. Type IV – fractures in the middle third creating a short central fracture fragment.
diaphyseal segmental tibial fractures (Melis Type III) and short (Melis Type IV) in a cadaveric model with differing degrees of soft tissue stripping. Materials and methods Institutional Review Board approval was obtained to perform the study. Eighteen fresh-frozen lower limb cadaveric specimens (9 matched pairs) were obtained from Department of Anatomy, University of Calgary. One specimen was excluded secondary to pathologic bone and one specimen was used as a trial to optimize the methodology and time points for measuring rotational displacement. A total of 16 specimens were included in our final results. The median age of the cadaveric specimens was 85 years (68–92). There were 12 male specimens and 4 female specimens. The mean intramedullary canal size for the specimens at ream to fit was 11.8 mm. The cadaveric specimen was secured with a clamp around the femur and 1.6 mm unicortical K-wires were inserted into the tibial tuberosity, midportion of the segmental fracture fragment and mid malleolar point in a parallel fashion using a ruler (Fig. 2A and B). Small vertical stab incisions were used and an oscillating saw (1.5 cm blade) used to create a transverse segmental tibia fracture, either 2.5 cm (Melis Type IV fracture) or 12 cm (Melis Type III fracture) in length with the midportion of the tibia (isthmus) at the centre of the fracture fragment (measured equidistant from the tibial plafond and plateau). This process was repeated to create a same level segmental fibula fracture either 3.5 cm or 12 cm in length. With the fracture reduced, all three K-wires were parallel. A total of 8 Type III and 8 Type IV fractures were used.
Soft tissue stripping was performed sharply with a scalpel blade. In the specimens classified as 0% soft tissue stripping access to the segmental fracture to use the oscillating saw was made by 2 cm vertical incisions over the antero-medial border of the tibia; 50% soft tissue stripping all of the soft tissue attachments were removed from the antero-lateral border of the tibia and interosseous membrane was left intact. When 100% soft tissue stripping was performed, all of the antero-lateral and posterior tissues including the inter-osseous membrane were dissected from the segmental tibial fragment. Linear circumferential incisions were used to create tracts for the K-wires to rotate freely as during the methodology optimization K-wires were not fully rotating due to soft tissue impedance (Fig. 3). If a greater degree of rotational displacement occurred then the K-wire in the intermediate fragment was removed in order to visualize this and prevent impedance of rotation. A medial parapatellar approach was used to perform a standardized intra-medullary reaming technique with new reamers (Expert Tibial Nail, Synthes, Mississauga, ON, Canada) starting with an 8.5 mm end-cutting reamer then increased sequentially in 0.5 mm increments until the canal had been over reamed by one reamer size. The size at which ream to fit was achieved was noted for each specimen when cortical chatter was first achieved. As the tibia was reamed by one investigator, a second maintained a manual reduction of the fracture fragment using axial load. The degree of axial load applied was judged by the investigator in order to maintain an adequate fracture reduction under direct visualization as may occur during freehand intra-medullary tibial nail. The fracture fragment was anatomically reduced under direct
M.H. Arastu et al. / Injury, Int. J. Care Injured 46 (2015) 643–648
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Fig. 2. (A, B) The cadaveric specimen was secured in a clamp attached to the distal femur and unicortical K-wires inserted in a parallel fashion in the tibial tuberosity, segmental fracture fragment and mid malleolar point in order to measure the rotational displacement with a goniometer.
visualization prior to each subsequent reamer insertion. Parallelism of the K-wires was used as an additional guide to judge fracture reduction. Rotational displacement of the tibial segment was measured for each reamer size with a goniometer between the proximal and segmental fracture K-wires. For each reamer size, displacement was recorded at 3 time points, initially when the reamer entered the fracture fragment at maximal rotational displacement; when the reamer passed from the segmental fracture into the distal tibia and the final rotational displacement of the tibial segment when the reamer was withdrawn. No intramedullary tibial nails were used in this study as the process of reaming causing rotation of segmental fracture fragments was being investigated. Four specimens (Melis Type III (n = 2), Melis Type IV (n = 2)) were reamed with 0%, 50% and 100% soft tissue stripping respectively. Two specimens (Melis Type III (n = 1), Melis Type IV (n = 1)), with 100% soft tissue stripping were plated with a 4 hole one third tubular small fragment plate on the posteromedial tibial border at the
level of the proximal fracture line using unicortical non locked 3.5 mm screws (2 proximal and 2 distal to fracture) prior to reaming in order to prevent rotational displacement of the fracture. Two specimens (Melis Type III (n = 1), Melis Type IV (n = 1)), each with 100% soft tissue stripping, were reamed with the fracture fragment held in place with a pointed reduction clamp (Fig. 4). Statistical analysis Statistical analysis was performed using IBM SPSS Statistics v19 (IBM, New York, New York, USA). An Independent Samples Mann– Whitney U test was computed on degrees of rotational displacement and reamer size by soft tissue stripping. A Univariate General Linear Model Analysis was used to compare fracture type and percentage soft tissue stripping by degrees of rotational displacement. A Bonferroni post hoc test was then conducted to see if there was a statistical difference between percentage soft tissue stripping groups. The level of significance was set at p < 0.05.
Fig. 3. (A, B) Soft tissue impedance prevented free rotation of the K-wire in the segmental fracture fragment during intra-medullary reaming (A) and creating a linear soft tissue tract allowed free rotation on order to measure rotation accurately (B).
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Fig. 4. The prevention of rotational displacement is demonstrated using a pointed reduction clamp during intra-medullary reaming.
Results The mean rotational displacement across all fracture types and reamer sizes for the 0%, 50% and 100% soft tissue stripping groups was 10.4 (SD 9.9), 12.8 (SD 13.7) and 208.1 (SD 158.7) degrees respectively. The difference in rotation between the 0% and 100% group, as well as the 50% and 100% group were statistically significant for both Type III and Type IV fractures (p < 0.0001). The increasing rotational displacement with increasing soft tissue stripping is shown in Fig. 5. Table 1 shows the mean rotational displacement for differing amounts of soft tissue stripping for both Type III and IV fractures. There was a significant difference in terms of mean rotational displacement between fracture types, with Type III fractures showing more rotation than Type IV fractures at 100% soft tissue stripping, as shown in Fig. 4 (p < 0.0001). Table 2 shows the mean rotational displacement of the segmental fracture fragment with increasing reamer sizes for all percentages of soft tissue stripping as well as individually for 0%, 50% and 100% stripping. Within each group there was a statistically significant increase in the degree of rotational displacement as reamer size increased, with the maximal rotation occurring when the tibia was over reamed by one reamer size (p < 0.0001). At 100% soft tissue stripping, when the tibia was reamed to fit, the segmental fragment spun freely (>360 degrees). On removal of the reamer following the initial rotational displacement there was no recoil of the displaced fracture fragment back to a less rotationally displaced position in any of the specimens investigated. The control specimens (unicortical plate (n = 2) and clamp (n = 2)) maintaining fracture reduction during reaming showed no rotational displacement of the segmental fracture fragment at 100% soft tissue stripping. Discussion Segmental tibia fractures are high-energy injuries with extensive soft tissue stripping and risk of complications is significant [1,3,4,12,15,16]. To the best of our knowledge this is the first study to show that segmental tibia fractures rotate secondary to intramedullary reaming. The mean rotational displacement for both Melis Type III and IV fractures was 10.4, 12.8 and 208.1 degrees for 0, 50 and 100% soft tissue stripping respectively. This degree of rotational displacement may further jeopardize remaining vascular attachments to the fracture fragment and predispose the patient to delayed healing, infection, mal-union or non-union. Long segmental fractures (12.5 cm) rotated to a greater degree than short (2.5 cm) fractures in this study and were statistically
Fig. 5. (A, B) The degree of rotational displacement with 0%, 50% and 100% soft tissue stripping with increasing reamer size for Type III (12.5 cm segmental fracture fragment) (A) and Type IV (2.5 cm segmental fracture fragment) (B). Not ream to fit defined by reamer sizes where no cortical chatter present; ream to fit defined by first cortical chatter and over ream defined by reaming beyond first cortical chatter by 1 mm.
significant. The reason for this may be that a longer segmental fracture fragment will be the result of a higher energy injury and as a result have more extensive soft tissue stripping. In addition to this the longer segmental fracture fragment will have a longer Table 1 Mean rotational displacement of segmental fracture fragment in Type III and IV fractures with differing amounts of soft tissue stripping. Melis fracture type
Soft tissue stripping (%)
Mean rotational displacement (degrees) (SD)
p-Value
Type III
0 50 100 0 50 100 0 50 100
11.67 12.95 307.27 8.53 12.63 135.33 10.37 12.80 208.08
<0.0001
Type IV
Type III and IV
(12.0) (16.5) (118.1) (5.5) (9.9) (147.1) (9.9) (13.7) (158.7)
<0.0001
M.H. Arastu et al. / Injury, Int. J. Care Injured 46 (2015) 643–648 Table 2 (A, B) Mean rotational displacement of segmental fracture fragment with different reamer sizes (A – Type III and B – Type IV fractures. End cutting reamer = 8.5 mm; ream to fit defined by first cortical chatter and over ream defined by reaming beyond first cortical chatter by 1 mm. Soft tissue stripping (%) A 0
50
100
All
B 0
50
100
All
Reamer size
Mean rotational displacement (degrees) (SD)
p-Value
8.5 mm Ream to fit Over ream 8.5 mm Ream to fit Over ream 8.5 mm Ream to fit Over ream 8.5 mm Ream to fit Over ream
2.5 (3.5) 25 (7.1) 32.5 (3.5) 0 (0) 37.5 (10.6) 42.5 (3.5) 200 (226.3) 360.00 (0) 360 (0) 67.5 (144.1) 140.8 (169.9) 145 (166.6)
<0.0001
8.5 mm Ream to fit Over ream 8.5 mm Ream to fit Over ream 8.5 mm Ream to fit Over ream 8.5 mm Ream to fit Over ream
7.5 (3.5) 12.5 (3.5) 20 (0) 7.5 (3.5) 25 (7.1) 32.5 (3.5) 15 (21.2) 360.00 (0) 360 (0) 10 (10.5) 132.5 (176.3) 137.5(172.4)
<0.0001
isthmic region of bone in contact with the reamer and torsional displacement as a result would be more likely. In this study there was a statistically significant increase in the degree of rotational displacement as reamer size increased in both Type III and IV fractures with more soft tissue stripping, with the maximal rotation occurring when the tibia was over reamed by one reamer size. At 100% soft tissue stripping, when the tibia was reamed to fit, the segmental fragment spun freely (>360 degrees). Kakar and Tornetta [16] published a series of 62 consecutive patients with closed and open segmental tibia fractures (AO-OTA 42-C2) treated with unreamed tibial nails and concluded that this technique was associated with high union rates (91%), few complications, and limited indications for secondary procedures in the management of segmental tibia fractures. Unreamed nails were thought to be less likely to disturb the fracture fragment’s precarious blood supply. However, the use of small diameter nails may result in an increased incidence of mal-unions as they may not provide adequate stability acutely or during the healing phase [17]. Woll and Duwelius [11] reported an incidence of 29% of malunions in their series of segmental tibia fractures treated with unreamed nails. Singer and Kellam [17] reported 49% of fractures were malunited, particularly in the proximal third of the diaphysis. Due to the prolonged healing time for segmental tibia fractures and the risk of mal-union and implant failure a carefully performed reamed tibial nail may be more advantageous than an unreamed nail but prevention of rotational displacement is paramount. Melis et al. described in 1981 that during blind reaming, any undesirable rotation of the intermediate fragment was controlled manually and rotation was undesirable because it tends to tear the residual vascular connections of the fragments and therefore, cautious progressive reaming was required but did not explain these statements any further [1]. Giannoudis et al. also stated that the use of a large pointed reduction clamp was found to be very
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useful to reduce and stabilize the segmental fracture to prevent spinning and mal-alignment during reaming and nail insertion [4]. The use of a Farabeuf [13] clamp or unicortical plate application [18] has been described to maintain the reduction of segmental tibia fractures but not specifically to prevent undesirable rotation of the intermediary segment. In this study unicortical plating of the proximal fracture and the use of a large pointed reduction clamp prevented any rotational displacement in Type III and IV fractures with 100% soft tissue stripping. However, the use of a plate to prevent rotation in a fracture that has a compromised soft tissue envelope may not be the optimal method to stabilize the fracture during reaming. The use of this technique in this study was to provide another control group in addition to fractures stabilized with a percutaneous reduction clamp. The use of the pointed reduction clamp should not significantly strip any further soft tissue from the intermediary fracture segment and therefore may be more advantageous when compared to unicortical plating. The limitations of this study were that fresh frozen cadaveric tissue was used and the sample size was small. The methodology used has compromised the soft tissue envelope even in the group with 0% soft tissue stripping and must be taken into account and an over estimation of rotation is a possibility. In addition, transverse osteotomies with no interdigitation of fracture fragments to resist rotation is a less likely clinical scenario and may lead to an over estimation of the effect of soft tissue stripping on fragment rotation. No radiographic assessment of fractures was performed during the reaming procedure but the fracture lines were directly visible through the incisions used to create the osteotomies and as a result reduction of the fracture during reaming was accurate. Crude assessment of rotation using a goniometer was performed using K-wires to determine displacement that is subject to human error but during intra-medullary nail fixation, assessment of rotation based upon intra-operative radiographic images is often very difficult. The point at which first cortical chatter was noted is subjective and may have varied depending on the cortical bone density, which would have been compromised given the age of the cadaveric specimens. Intra-medullary nail fixation of segmental tibia fractures is technically demanding. The surgical technique is critical in order to preserve the residual soft tissue envelope and vascular supply to significantly damaged tissue and obtain an accurate reduction of the fracture. Reaming to fit is a significant risk factor for causing rotational displacement of the intermediate fragment but the potential biomechanical benefits of a larger intra-medullary nail are appealing. Over reaming must be avoided. The routine use of a pointed reduction clamp for both long and short diaphyseal segmental fractures is recommended which can prevent any undesirable rotation. The consideration of unicortical plating of the proximal portion of the segmental fracture can also be performed but this does risk more extensive soft tissue stripping of the fracture fragment. Financial disclosure The authors report no financial disclosures related to the manuscript. Conflict of interest None declared. Acknowledgements We would like to thank Mr Nolan Brown (DePuy Synthes, Canada) for the provision of the intra-medullary reamers for this study.
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