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Biomechanical Concepts for Fracture Fixation

Bottlang, Michael PhD*; Schemitsch, Christine E.; Nauth, Aaron MD, FRCSC; Routt, Milton Jr MD§; Egol, Kenneth A. MD; Cook, Gillian E. MHSc†,¶; Schemitsch, Emil H. MD, FRCSC†,**

Author Information
Journal of Orthopaedic Trauma: December 2015 - Volume 29 - Issue - p S28-S33
doi: 10.1097/BOT.0000000000000467

Abstract

INTRODUCTION

Selection of the appropriate fracture fixation method is a multifaceted issue that depends on the location and type of fracture, the inherent stability at the fracture site, and the desired degree of flexibility and motion required for healing. This review assesses current fixation devices used in radial head and coronoid fractures, sacral fractures, periprosthetic and distal femur fractures, and syndesmosis injuries and discusses the biomechanics of each.

RADIAL HEAD AND CORONOID FRACTURES: BIOMECHANICAL EVIDENCE FOR MODERN APPROACHES

Several biomechanical studies have provided important evidence that can help to guide the management of radial head and coronoid fractures of the elbow. The majority of these have focused on the importance of appropriate management of these fractures when combined with ligamentous injury (ie, complex elbow instability or fracture-dislocations of the elbow). From these studies, several noteworthy concepts can be obtained.

First, stable fixation or replacement of the radial head in the setting of traumatic elbow instability is critical. Multiple biomechanical investigations have demonstrated that the radial head is critically important to elbow stability when the ligaments of the elbow have been disrupted.1–31–31–3 These studies have further shown that elbow stability is best restored by ligamentous repair combined with stable radial head fixation or replacement. This biomechanical literature, combined with the clinical evidence which has shown that significantly displaced radial head fractures are an important predictor of elbow dislocation,4 suggests that these fractures are best treated with stable fixation or replacement in combination with ligamentous repair. Practically speaking, this means that radial head excision is contraindicated in the setting of complex elbow instability and that if stable fixation cannot be achieved, radial head replacement should be performed. This, combined with the clinical evidence of poor outcomes in comminuted, displaced, radial head fractures treated with open reduction and internal fixation (ORIF),5 has led to a distinct shift by orthopaedic trauma surgeons toward radial head replacement in the setting of complex elbow instability, even in young patients.

Second, correct sizing of a radial head replacement is critical to restoring joint kinematics and contact pressures, and yet improper sizing is one of the most commonly encountered surgical errors. This is typically due to overstuffing of the joint in an effort to compensate for instability of the elbow. Biomechanical studies have demonstrated that improper sizing of the radial head replacement results in increased joint contact pressures, elbow instability, and altered biomechanics in the forearm.6,76,7 These studies have shown that the best restoration of elbow stability and mechanics occurs with accurate radial head sizing and ligamentous repair. Several anatomic and radiographic landmarks for accurate radial head sizing have been described in the literature and should be used accordingly.8

Third, stable fixation of a complete radial head fracture is best achieved with crossed screws or a fixed angle device, particularly in the setting of incomplete cortical contact between the head and the neck. Two separate biomechanical studies have shown the importance of using such constructs to obtain stable radial head fixation in the setting of a complete articular fracture of the radial head.9,109,10

Finally, when considering the need for fixation of the coronoid in the setting of complex elbow instability, both the size and location of the coronoid fragment is important. Several biomechanical studies evaluating the influence of coronoid fragment size and fixation in the setting of terrible triad injuries have shown that it is not necessary to perform fixation of coronoid fragments involving less than 40%–50% of the coronoid, provided that radial head stability is restored and ligament repair is performed.11–1311–1311–13 This literature suggests that previous thinking, which recommended that coronoid fragments of any size be fixed in the setting of terrible triad injuries, was incorrect. Subsequent clinical literature has provided further support for this notion.14 Biomechanical research has shown that the location of the coronoid fracture is also important in elbow stability because even small anteromedial facet fractures (>5 mm) can be significantly unstable and likely warrant fixation.15

UNSTABLE SACRAL FRACTURES: IS STANDARD ILIOSACRAL SCREW FIXATION ADEQUATE?

Unstable pelvic ring injuries usually result from high-energy traumatic events, such as automobile accidents, and in osteopenic patients due to less violent incidents such as falls. Sacral fractures are common in pelvic ring injuries; their instability depends on numerous factors, and the foremost among them is the magnitude of the applied traumatic load.

Iliosacral screw insertion became a popular fixation method for unstable posterior pelvic ring injuries because they could be safely inserted via small surgical incisions, which lowered wound complication rates, operative blood losses, and operative times significantly, while avoiding deep pelvic hematoma.16 Furthermore, high-quality intraoperative fluoroscopic imaging was available to guide and assess closed posterior pelvic reduction techniques and iliosacral screw insertions. “Standard” iliosacral screw fixation was commonly defined as a single, cannulated, 7-mm screw inserted from the lateral iliac cortical surface, across the sacroiliac joint, through the sacral ala below the alar cortical surface and above the nerve root tunnel, and ending in the upper sacral vertebral body or contralateral ala (see Figure, Supplemental Digital 1 Content, http://links.lww.com/BOT/A546). The screw starting point, directional aim, and length were determined by the particular injury pattern and osteology. The development of longer, 7-mm-diameter, cannulated, cancellous screws allowed for transiliac–transsacral (TITS) screw orientations to be used (see Figure, Supplemental Digital Content, http://links.lww.com/BOT/A546). One clinical study showed that fixation failure rates were significantly lowered in patients with unstable posterior pelvic injuries when TITS screws were used compared with shorter length screws.17 Patient compliance must also be considered when planning the sacral fixation construct because early unprotected weight bearing after surgery can lead to fixation failure. “Standard” iliosacral screw fixation alone is therefore not advocated for potentially noncompliant patients.

In several clinical series, a “standard” iliosacral screw in the upper sacral segment fixation construct failed to maintain the reduction, especially with certain injury patterns.16,1816,18 The most common factor associated with “standard” fixation failure was a highly displaced sacral fracture that had been poorly reduced, either after closed manipulation or after open reduction. Poor reduction of a sacral fracture was also noted to diminish the safe region available for iliosacral screw insertion.19 Unsurprisingly, the more unstable fracture patterns also correlated with higher failure rates.18 Another factor noted to increase failure in clinical practice was insufficient stabilization of the other pelvic ring injury sites. This correlates with biomechanical studies, which found that reduction and fixation of each injury site improved the overall fixation construct strength.20 Transverse sacral fracture patterns require additional consideration with regard to iliosacral screw fixation. U-shaped sacral fractures cause instability of the entire spine, along with the upper sacral segment and the rest of the pelvis. U-shaped fractures exclude overall ring involvement, but fixation failures, have occurred in association with standard iliosacral screw fixation.21 Thus, for U-shaped sacral fractures, TITS screws located in the safe sacral osseous fixation pathway, cranial to the transverse fracture, provide stable and durable fixation. Y-shaped and H-shaped sacral fracture patterns are U-shaped fractures that are further complicated by associated pelvic ring injuries. For these injuries and U-shaped fractures that require spinal decompression due to cauda equina syndrome, supplementary spinopelvic fixation should be considered.

Based on clinical and biomechanical studies in addition to clinical experience, “standard” iliosacral screw fixation (one upper sacral segment screw) is more likely to be a successful treatment for patients with rotationally unstable injuries, especially when the anterior pelvic injury and the sacral fracture are accurately reduced and stabilized. For more unstable sacral fracture patterns with vertical or multiplanar instability, “standard” iliosacral screw fixation will not provide adequate stability. Following accurate sacral fracture reduction, several iliosacral screws of appropriate lengths, located at multiple sacral levels, are optimal. Other important factors that contribute to overall pelvic ring stability and the durability of the fixation construct include anterior pelvic injury reduction quality and the choice of implant. Poor anterior pelvic reductions and less stable anterior pelvic fixation devices, such as external fixation, place additional stress on the sacral fracture fixation construct. Lumbopelvic fixation can also be used to supplement iliosacral screw fixation.

PERIPROSTHETIC FEMUR FRACTURES: 90/90 FIXATION VERSUS A SINGLE LOCKING PLATE?

Periprosthetic femur fractures are a complication of total hip arthroplasty, and although uncommon, they are increasing in frequency with the aging population.22,2322,23 Classification of periprosthetic femur fractures is based on the Vancouver system.24 The focus of this review is Vancouver B1 fractures, which account for a majority of periprosthetic femur fractures.22,2522,25 Vancouver B1 fractures occur around or just distal to a stable prosthesis. Correctly identifying the fracture type is imperative to providing the best chance for a successful outcome.24,2624,26 Vancouver B1 fractures are particularly difficult to treat because they have a high complication rate, and the proper treatment method is still under debate.23,2723,27

A 90/90 fixation construct for a periprosthetic femur fracture involves a plate placed laterally and a cortical allograft strut placed anteriorly. Strut allografts allow greater mechanical stability and increase bone stock, leading to improved fracture healing.28,2928,29 Benefits of using a locking plate alone include a minimally invasive technique of insertion, increased angular stability, and a decreased need for plate contouring.23,2823,28

Biomechanical studies have indicated that a lateral cable plate with an allograft strut placed anteriorly may provide superior fixation for periprosthetic femoral fractures. A study by Zdero et al27 showed that 90/90 fixation achieved equal or superior results in axial stiffness, lateral bending stiffness, and torsional stiffness tests compared with locking plates alone. Moreover, the results seen with the single locking plate constructs were similar to nonlocked cable plates. These results were maintained with cyclic loading. A locked plate alone was less stiff in bending and had a lower load to failure than 90/90 allograft strut–plate constructs with or without locking screws.30

A systematic review conducted by Dehghan et al26 compared different operative treatments for Vancouver B1 periprosthetic femur fractures. Two of the treatments that were compared included ORIF with cable plates and cortical strut allografts and ORIF with locking plates. This systematic review indicated that locking plates had a higher rate of nonunion and hardware failure compared with a cable plate with a cortical strut allograft (90/90 fixation construct).

Both the biomechanical evidence and systematic review suggest that 90/90 fixation yields superior results compared with a single locking plate and should be used in the treatment of patients with a Vancouver B1 periprosthetic femur fracture when maximum rigidity is required. In particular, a locking plate should be avoided if there is no medial cortical contact at the fracture site and with transverse fractures.

DISTAL FEMUR FRACTURES: FAR CORTICAL VERSUS CONVENTIONAL LOCKING SCREWS—IS THERE A NEW GOLD STANDARD?

Far cortical locking (FCL) is a strategy to dynamize a locked plating construct to promote biologic fracture healing by callus formation.31 Applying a locking plate with FCL screws instead of conventional locking screws reduces the construct stiffness and enables controlled axial motion that leads to faster and stronger fracture healing.32,3332,33

The original gold standard for flexible fracture stabilization promoted callus formation using elastic fixation constructs, such as intramedullary nails, external fixators, and functional bracing.34,3534,35 This flexible fixation strategy is supported by more than 50 years of research demonstrating that controlled dynamization of a fracture promotes callus formation and improves the speed and strength of fracture healing.36–4036–4036–4036–4036–40 For example, Goodship and Kenwright37 demonstrated that 1-mm axial dynamization delivered more than 3 times stronger and 2 times faster healing compared with rigid fixation. Conversely, deficient fracture motion caused by overly stiff fixation constructs can suppress secondary fracture healing, contributing to delayed union, nonunion, osteolysis, and fixation failure.41,4241,42

Locking plates can provide stronger and more durable fixation than nonlocked plates. However, locked plating constructs are also inherently stiff and can suppress motion at the fracture site to levels insufficient for stimulation of callus formation.41,4341,43 Consequently, locked plating of distal femur fractures causes deficient and asymmetric callus formation, with the least amount of callus being deposited at the near cortex.41,4241,42 This concern is corroborated in recent studies on locked plating of distal femur fractures, documenting nonunion rates of 10%–23%,44–4744–4744–4744–47 and a 31% reoperation rate for open fractures.48

Yet with the advent of locked plating came novel strategies for dynamization31,38,4931,38,4931,38,49 because locking plates derive stability from fixed-angle locking screws and thus no longer require plate compression onto the bone surface. The strategy of FCL enables controlled and symmetric interfragmentary motion through elastic flexion of screw shafts within a motion envelope at the near cortex.31 A biomechanical study demonstrated that FCL screws enable axial dynamization without sacrificing construct stability.32 In an ovine fracture healing study, FCL constructs delivered consistent and circumferential callus bridging and yielded 157% stronger healing compared with standard locked plating.33 Clinically, a prospective study of 31 consecutive distal femur fractures stabilized with FCL constructs reported no implant or fixation failure, an average time to union of 16 weeks, and a nonunion rate of 3%.50 The FCL strategy has been implemented in commercial implants (MotionLoc FCL screws; Zimmer, Warsaw, IN and Dynamic Locking Screws; Synthes, West Chester, PA) and has been clinically used for the fixation of distal femur fractures,50–5250–5250–52 tibial fractures,53 and humeral fractures.54 FCL fixation has also been simulated using standard locking screws by means of overdrilling55 or slotting56 of the near cortex. Moreover, “active” locking plates have been developed that provide controlled axial dynamization through elastic suspension of the locking holes within the plate, while using standard locking screws.49 However, to date, only FCL screws have been fully evaluated by benchtop and cadaveric testing,32,5732,57 a prospective, randomized, animal study,33 and clinical trials.50 Alternative strategies for dynamization should therefore be viewed with caution until they have been fully evaluated.

In conclusion, FCL combines the superior fixation strength of fixed-angle locking screws with controlled dynamization to promote biologic healing. Given the established benefits of dynamization and the evidence that stiff locking constructs can suppress healing, a new standard for locked plating of distal femur fractures should account for dynamization to promote healing.

SYNDESMOTIC INJURIES: WHAT IS THE IDEAL FIXATION CONSTRUCT?

Physiologic motion at the syndesmosis is complex. Normal motion at the ankle necessitates translational, rotational, and migrational movements of the fibula at the syndesmosis.58 During plantarflexion, the fibula migrates distally, translates anteromedially, and internally rotates. Dorsiflexion results in migration of the fibula proximally, posterolateral translation, and external rotation. External rotation of the foot causes a medial translation, posterior displacement, and external rotation of the fibula through the syndesmosis.59 Screw fixation alters fibular translation and rotation.60–6260–6260–62 As a result, syndesmotic screw fixation has been shown to restrain the mortise-width variations during foot dorsiflexion and plantarflexion with reduced range of motion for horizontal translation.63

Likewise, syndesmotic screws cannot prevent syndesmotic widening when subjected to weight bearing.64 Rigid fixation of the syndesmosis restricts normal physiologic motion of the distal tibiofibular joint, which may adversely affect ankle biomechanics, as reflected in a smaller joint contact area and a decrease in anterior and posterior drawer tests.65 Clinically, outcomes 1 year after syndesmotic screw fixation were significantly better in patients with removed, fractured, or loosened screws, according to a retrospective analysis.66

Tricortical screws may allow for more physiologic motion, with a resultant higher rate of associated hardware loosening.67 Bioabsorbable screws as an alternative to metallic screws have comparable biomechanical properties and outcomes, while obviating the need for removal.68 Similar outcomes exist for all fixation constructs regarding pain, range of motion, and functional assessments.

Suture-button devices are still a relatively new technology. Klitzman et al conducted a cadaveric study to analyze suture-button biomechanics in comparison to screw fixation. They found that suture-button fixation preserved reduction after cycling with submaximal loads to a degree similar to an intact syndesmosis. Also, increased physiologic movement of the fibula in the sagittal plane was noted when compared with tricortical screw fixation.69 This must be tempered with Teramoto et al,70 who found a potential limitation of suture-button devices to be insufficient fixation in multidirectional testing.

One study found screw fixation to be closer to native ankle kinematic motion in anterior/posterior and medial/lateral motions, although suture-buttons were closer to native fibular rotation. They also concluded that FiberWire buttons were consistently unable to maintain reduction with the forces applied, whereas suture endobuttons had a performance equal to or greater than screw fixation when subjected to rotational torque.71

There are other construct types and concepts that have been reported. Kirschner wire fixation has been shown to be comparable to screw fixation in Weber C fractures with regard to joint motion and contact surface.62 This technique may provide sufficient stabilization in select fractures with syndesmotic injury.72 Posterior malleolus fracture fixation reestablishes the posterior tibiofibular ligament of the syndesmosis, while potentially allowing for normal ankle kinematics. Posterior malleolus fixation alone has been shown to result in better clinical outcomes than when combined with transsyndesmotic screw placement.73

With regard to clinical outcomes, no major differences have been noted in functional outcomes between single and double screws, tricortical and quadricortical screws, transsyndesmotic and suprasyndesmotic screws, stainless steel and titanium, or metal and bioabsorbable screws to date.72,74–7672,74–7672,74–7672,74–76 At present, there is no “ideal construct” for syndesmotic fixation, and as such, it should be selected based on surgeon preference and experience. Screw fixation remains the most stable and reliable construct in moderate-to-severe ankle injuries involving the syndesmosis.

CONCLUSIONS

Depending on the fracture type, different fixation constructs may be optimal. Orthopaedic surgeons should carefully select the fracture fixation construct to optimize stability and promote healing.

REFERENCES

1. King GJ, Zarzour ZD, Rath DA, et al.. Metallic radial head arthroplasty improves valgus stability of the elbow. Clin Orthop Relat Res. 1999;368:114–125.
2. Beingessner DM, Dunning CE, Gordon KD, et al.. The effect of radial head excision and arthroplasty on elbow kinematics and stability. J Bone Joint Surg Am. 2004;86:1730–1739.
3. Charalambous C, Stanley J, Siddique I, et al.. Radial head fracture in the medial collateral ligament deficient elbow; biomechanical comparison of fixation, replacement and excision in human cadavers. Injury. 2006;37:849–853.
4. Rineer CA, Guitton TG, Ring D. Radial head fractures: loss of cortical contact is associated with concomitant fracture or dislocation. J Shoulder Elbow Surg. 2010;19:21–25.
5. Ring D, Quintero J, Jupiter JB. Open reduction and internal fixation of fractures of the radial head. J Bone Joint Surg Am. 2002;84:1811–1815.
6. Van Glabbeek F, Van Riet R, Baumfeld J, et al.. Detrimental effects of overstuffing or understuffing with a radial head replacement in the medial collateral-ligament deficient elbow. J Bone Joint Surg Am. 2004;86:2629–2635.
7. Lanting BA, Ferreira LM, Johnson JA, et al.. The effect of radial head implant length on radiocapitellar articular properties and load transfer within the forearm. J Orthop Trauma. 2014;28:348–353.
8. Frank SG, Grewal R, Johnson J, et al.. Determination of correct implant size in radial head arthroplasty to avoid overlengthening. J Bone Joint Surg Am. 2009;91:1738–1746.
9. Giffin JR, King GJ, Patterson SD, et al.. Internal fixation of radial neck fractures: an in vitro biomechanical analysis. Clin Biomech. 2004;19:358–361.
10. Burkhart KJ, Mueller LP, Krezdorn D, et al.. Stability of radial head and neck fractures: a biomechanical study of six fixation constructs with consideration of three locking plates. J Hand Surg Am. 2007;32:1569–1575.
11. Jeon I, Sanchez-Sotelo J, Zhao K, et al.. The contribution of the coronoid and radial head to the stability of the elbow. J Bone Joint Surg Br. 2012;94:86–92.
12. Hartzler RU, Llusa-Perez M, Steinmann SP, et al.. Transverse coronoid fracture: when does it have to be fixed? Clin Orthop Relat Res. 2014;472:2068–2074.
13. Beingessner DM, Stacpoole RA, Dunning CE, et al.. The effect of suture fixation of type i coronoid fractures on the kinematics and stability of the elbow with and without medial collateral ligament repair. J Shoulder Elbow Surg. 2007;16:213–217.
14. Papatheodorou LK, Rubright JH, Heim KA, et al.. Terrible triad injuries of the elbow: does the coronoid always need to be fixed? Clin Orthop Relat Res. 2014;472:2084–2091.
15. Pollock JW, Brownhill J, Ferreira L, et al.. The effect of anteromedial facet fractures of the coronoid and lateral collateral ligament injury on elbow stability and kinematics. J Bone Joint Surg Am. 2009;91:1448–1458.
16. Routt MC Jr, Simonian PT, Mills WJ. Iliosacral screw fixation: early complications of the percutaneous technique. J Orthop Trauma. 1997;11:584–589.
17. Blaisdell GY, Krieg JC, Routt MLC Jr, Transiliac-transsacral screw fixation in c-type pelvic ring injuries reduces postoperative failure. Presented at: OTA Annual Meeting; October 5, 2012; Minneapolis, MN.
18. Griffin DR, Starr AJ, Reinert CM, et al.. Vertically unstable pelvic fractures fixed with percutaneous iliosacral screws: does posterior injury pattern predict fixation failure? J Orthop Trauma. 2003;17:399–405.
19. Reilly MC, Bono CM, Litkouhi B, et al.. The effect of sacral fracture malreduction on the safe placement of iliosacral screws. J Orthop Trauma. 2003;17:88–94.
20. Simonian PT, Routt MC. Biomechanics of pelvic fixation. Orthop Clin North Am. 1997;28:351–367.
21. Nork SE, Jones CB, Harding SP, et al.. Percutaneous stabilization of u-shaped sacral fractures using iliosacral screws: technique and early results. J Orthop Trauma. 2001;15:238–246.
22. Pike J, Davidson D, Garbuz D, et al.. Principles of treatment for periprosthetic femoral shaft fractures around well-fixed total hip arthroplasty. J Am Acad Orthop Surg. 2009;17:677–688.
23. Graham SM, Moazen M, Leonidou A, et al.. Locking plate fixation for vancouver b1 periprosthetic femoral fractures: a critical analysis of 135 cases. J Orthopaedic Sci. 2013;18:426–436.
24. Brady OH, Garbuz DS, Masri BA, et al.. The reliability and validity of the vancouver classification of femoral fractures after hip replacement. J Arthroplasty. 2000;15:59–62.
25. Sariyilmaz K, Dikici F, Dikmen G, et al.. The effect of strut allograft and its position on vancouver type b1 periprosthetic femoral fractures: a biomechanical study. J Arthroplasty. 2014;29:1485–1490.
26. Dehghan N, McKee MD, Nauth A, et al.. Surgical fixation of vancouver type b1 periprosthetic femur fractures: a systematic review. J Orthop Trauma. 2014;28:721–727.
27. Zdero R, Walker R, Waddell JP, et al.. Biomechanical evaluation of periprosthetic femoral fracture fixation. J Bone Joint Surg Am. 2008;90:1068–1077.
28. Buttaro MA, Farfalli G, Núñez MP, et al.. Locking compression plate fixation of vancouver type-b1 periprosthetic femoral fractures. J Bone Joint Surg Am. 2007;89:1964–1969.
29. Haddad FS, Duncan CP, Berry DJ, et al.. Periprosthetic femoral fractures around well-fixed implants: use of cortical onlay allografts with or without a plate. J Bone Joint Surg Am. 2002;84:945–950.
30. Talbot M, Zdero R, Schemitsch EH. Cyclic loading of periprosthetic fracture fixation constructs. J Trauma. 2008;64:1308–1312.
31. Bottlang M, Feist F. Biomechanics of far cortical locking. J Orthop Trauma. 2011;25(suppl 1):S21–S28.
32. Bottlang M, Doornink J, Fitzpatrick DC, et al.. Far cortical locking can reduce stiffness of locked plating constructs while retaining construct strength. J Bone Joint Surg Am. 2009;91:1985–1994.
33. Bottlang M, Lesser M, Koerber J, et al.. Far cortical locking can improve healing of fractures stabilized with locking plates. J Bone Joint Surg Am. 2010;92:1652–1660.
34. Uhthoff HK, Poitras P, Backman DS. Internal plate fixation of fractures: short history and recent developments. J Orthop Sci. 2006;11:118–126.
35. McKellop H, Hoffmann R, Sarmiento A, et al.. Control of motion of tibial fractures with use of a functional brace or an external fixator. A study of cadavera with use of a magnetic motion sensor. J Bone Joint Surg Am. 1993;75:1019–1025.
36. Claes LE, Heigele CA, Neidlinger-Wilke C, et al.. Effects of mechanical factors on the fracture healing process. Clin Orthop Relat Res. 1998(suppl 355):S132–S147.
37. Goodship AE, Kenwright J. The influence of induced micromovement upon the healing of experimental tibial fractures. J Bone Joint Surg Br. 1985;67:650–655.
38. Richter H, Plecko M, Andermatt D, et al.. Dynamization at the near cortex in locking plate osteosynthesis by means of dynamic locking screws: an experimental study of transverse tibial osteotomies in sheep. J Bone Joint Surg Am. 2015;97:208–215.
39. Uhthoff HK. Current concepts of internal fixation of fractures. Can J Surg. 1980;23:213–214.
40. Woo SL, Lothringer KS, Akeson WH, et al.. Less rigid internal fixation plates: historical perspectives and new concepts. J Orthop Res. 1984;1:431–449.
41. Lujan TJ, Henderson CE, Madey SM, et al.. Locked plating of distal femur fractures leads to inconsistent and asymmetric callus formation. J Orthop Trauma. 2010;24:156–162.
42. Roderer G, Gebhard F, Duerselen L, et al.. Delayed bone healing following high tibial osteotomy related to increased implant stiffness in locked plating. Injury. 2014;45:1648–1652.
43. Claes L. Biomechanical principles and mechanobiologic aspects of flexible and locked plating. J Orthop Trauma. 2011;25(suppl 1):S4–S7.
44. Henderson CE, Lujan TJ, Kuhl LL, et al.. 2010 mid-america orthopaedic association physician in training award: healing complications are common after locked plating for distal femur fractures. Clin Orthop Relat Res. 2011;469:1757–1765.
45. Hoffmann MF, Jones CB, Sietsema DL, et al.. Outcome of periprosthetic distal femoral fractures following knee arthroplasty. Injury. 2012;43:1084–1089.
46. Rodriguez EK, Boulton C, Weaver MJ, et al.. Predictive factors of distal femoral fracture nonunion after lateral locked plating: a retrospective multicenter case-control study of 283 fractures. Injury. 2014;45:554–559.
47. Vallier HA, Immler W. Comparison of the 95-degree angled blade plate and the locking condylar plate for the treatment of distal femoral fractures. J Orthop Trauma. 2012;26:327–332.
48. Ricci WM, Streubel PN, Morshed S, et al.. Risk factors for failure of locked plate fixation of distal femur fractures: an analysis of 335 cases. J Orthop Trauma. 2014;28:83–89.
49. Tsai S, Fitzpatrick DC, Madey SM, et al.. Dynamic locking plates provide symmetric axial dynamization to stimulate fracture healing. J Orthop Res. 2015;33:1218–1225.
50. Bottlang M, Fitzpatrick DC, Sheerin D, et al.. Dynamic fixation of distal femur fractures using far cortical locking screws: a prospective observational study. J Orthop Trauma. 2014;28:181–188.
51. Adams JD Jr, Tanner SL, Jeray KJ. Far cortical locking screws in distal femur fractures. Orthopedics. 2015;38:e153–e156.
52. Ries ZG, Marsh JL. Far cortical locking technology for fixation of periprosthetic distal femur fractures: a surgical technique. J Knee Surg. 2013;26:15–18.
53. Freude T, Schroter S, Gonser CE, et al.. Controlled dynamic stability as the next step in “biologic plate osteosynthesis”—a pilot prospective observational cohort study in 34 patients with distal tibia fractures. Patient Saf Surg. 2014;8:3.
54. Freude T, Schroeter S, Plecko M, et al.. Dynamic-locking-screw (dls)-leads to less secondary screw perforations in proximal humerus fractures. BMC Musculoskelet Disord. 2014;15:194.
55. Linn MS, McAndrew CM, Prusaczyk B, et al.. Dynamic locked plating of distal femur fractures. J Orthop Trauma. 2015;29:447–450.
56. Gardner MJ, Nork SE, Huber P, et al.. Less rigid stable fracture fixation in osteoporotic bone using locked plates with near cortical slots. Injury. 2010;41:652–656.
57. Doornink J, Fitzpatrick DC, Madey SM, et al.. Far cortical locking enables flexible fixation with periarticular locking plates. J Orthop Trauma. 2011;25(suppl 1):S29–S34.
58. Norkus SA, Floyd R. The anatomy and mechanisms of syndesmotic ankle sprains. J Athl Train. 2001;36:68.
59. Beumer A, Valstar ER, Garling EH, et al.. Kinematics of the distal tibiofibular syndesmosis: radiostereometry in 11 normal ankles. Acta Orthop Scand. 2003;74:337–343.
60. Huber T, Schmoelz W, Bölderl A. Motion of the fibula relative to the tibia and its alterations with syndesmosis screws: a cadaver study. Foot Ankle Int. 2012;18:203–209.
61. Ogilvie-Harris D, Reed S, Hedman T. Disruption of the ankle syndesmosis: biomechanical study of the ligamentous restraints. Arthroscopy. 1994;10:558–560.
62. Peter RE, Harrington R, Henley M, et al.. Biomechanical effects of internal fixation of the distal tibiofibular syndesmotic joint: comparison of two fixation techniques. J Orthop Trauma. 1994;8:215–219.
63. Bragonzoni L, Russo A, Girolami M, et al.. The distal tibiofibular syndesmosis during passive foot flexion. Rsa-based study on intact, ligament injured and screw fixed cadaver specimens. Arch Orthop Trauma Surg. 2006;126:304–308.
64. Beumer A, Campo MM, Niesing R, et al.. Screw fixation of the syndesmosis: a cadaver model comparing stainless steel and titanium screws and three and four cortical fixation. Injury. 2005;36:60–64.
65. Needleman RL, Skrade DA, Stiehl JB. Effect of the syndesmotic screw on ankle motion. Foot Ankle Int. 1989;10:17–24.
66. Manjoo A, Sanders DW, Tieszer C, et al.. Functional and radiographic results of patients with syndesmotic screw fixation: implications for screw removal. J Orthop Trauma. 2010;24:2–6.
67. Høiness P, Strømsøe K. Tricortical versus quadricortical syndesmosis fixation in ankle fractures: a prospective, randomized study comparing two methods of syndesmosis fixation. J Orthop Trauma. 2004;18:331–337.
68. Thordarson DB, Samuelson M, Shepherd LE, et al.. Bioabsorbable versus stainless steel screw fixation of the syndesmosis in pronation-lateral rotation ankle fractures: a prospective randomized trial. Foot Ankle Int. 2001;22:335–338.
69. Klitzman R, Zhao H, Zhang LQ, et al.. Suture-button versus screw fixation of the syndesmosis: a biomechanical analysis. Foot Ankle Int. 2010;31:69–75.
70. Teramoto A, Suzuki D, Kamiya T, et al.. Comparison of different fixation methods of the suture-button implant for tibiofibular syndesmosis injuries. Am J Sports Med. 2011;39:2226–2232.
71. den Daas A, van Zuuren WJ, Pelet S, et al.. Flexible stabilization of the distal tibiofibular syndesmosis: clinical and biomechanical considerations: a review of the literature. Strategies Trauma Limb Reconstr. 2012;7:123–129.
72. Van Heest TJ, Lafferty PM. Injuries to the ankle syndesmosis. J Bone Joint Surg Am. 2014;96:603–613.
73. Gardner MJ, Demetrakopoulos D, Briggs SM, et al.. Malreduction of the tibiofibular syndesmosis in ankle fractures. Foot Ankle Int. 2006;27:788–792.
74. Kukreti S, Faraj A, Miles J. Does position of syndesmotic screw affect functional and radiological outcome in ankle fractures? Injury. 2005;36:1121–1124.
75. DeGroot H, Al-Omari AA, El Ghazaly SA. Outcomes of suture button repair of the distal tibiofibular syndesmosis. Foot Ankle Int. 2011;32:250–256.
76. Wikerøy AK, Høiness PR, Andreassen GS, et al.. No difference in functional and radiographic results 8.4 years after quadricortical compared with tricortical syndesmosis fixation in ankle fractures. J Orthop Trauma. 2010;24:17–23.
Keywords:

coronoid fracture; radial head fracture; unstable sacral fractures; iliosacral screws; far cortical locking; interfragmentary motion

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