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Surgical Treatment of Posterior Tibial Plateau Fractures
Surgical Treatment of Posterior Tibial Plateau Fractures Julius Bishop, MD, and Michael Githens, MD Posterior tibial plateau fractures are not uncommon injuries and often necessitate surgical treatment. They are frequently unstable with knee flexion even in the absence of an axial load. As with other tibial plateau fractures, knee instability and articular incongruity are indications for surgery. Optimal reduction and fixation usually requires a direct surgical approach, which is dictated by the fracture location and morphology. Common fracture morphologies include a posteromedial fragment that may or may not be associated with a bicondylar tibial plateau fracture, a posterior shearing pattern that involve the posteromedial and posterolateral plateaus, and a fracture that is with posterolateral articular impaction. This article provides an overview of current concepts in the surgical treatment of posterior tibial plateau fractures with discussion on relevant surgical approaches and fixation strategies. Although the overall incidence of these injuries is relatively low, it is important for surgeons to recognize these injury patterns and treat them appropriately to optimize patient outcome. Oper Tech Orthop ]:]]]-]]] C 2015 Elsevier Inc. All rights reserved.
KEYWORDS Tibial plateau, trauma, surgical technique
Introduction
C
oronal plane fractures involving the posterior tibial plateau are increasingly recognized as injuries that require unique treatment strategies. Care must be given to the diagnosis and management of these injuries as they are easily overlooked, yet unstable patterns that necessitate fracturespecific surgical approaches and fixation strategies. Posterior fractures are rarely found in isolation. They are typically a result of a high-energy injury and are found in combination with additional fractures through the tibial plateau.1 Although the Schatzker and Moore classification schemes are frequently used to describe tibial plateau fractures, they do not specifically address posterior coronal plane patterns. Increased recent attention to these injury patterns has generated modifications of these classification systems as well as alternative classifications.2-6 Careful scrutiny of reformatted computed tomography scans and their 3-dimensional Department of Orthopaedic Surgery, Stanford University Medical Center, Redwood City, CA. Conflict of interest: Dr Bishop serves as a consultant for Globus Medical and receives royalties from Innomed. Dr Githens has no conflicts to report. *Address reprint requests to Julius Bishop, MD, Department of Orthopaedic Surgery, Stanford University Medical Center, 450 Broadway St, MC 6342, Redwood City, CA 94063. E-mail: [email protected]
http://dx.doi.org/10.1053/j.oto.2015.08.004 1048-6666//& 2015 Elsevier Inc. All rights reserved.
renderings is important in understanding these patters, as the fracture location and pattern would dictate the surgical approach and fixation strategy. Although indications for posterior fixation are controversial, there is a growing body of evidence to support direct anatomical reduction and fragment-specific fixation.
Clinical Relevance Posterior tibial plateau fractures are not uncommon. A clinically significant posteromedial fragment has been observed in 30%-59% of bicondylar patterns.7,8 These fragments involve approximately a quarter of the total tibial plateau surface and are significantly displaced in half of the cases.7,8 Posteromedial articular depression has also been observed in 50% of medial tibial plateau fractures (Schatzker IV patterns).9 Posterolateral fragments are the least common but still occur in up to 44% of fractures. These fragments tend to be smaller, involving an average of 15% of the surface area of the plateau.10,11 Cadaveric models confirm the unstable nature of these patterns. Displacement of the posteromedial fragment occurs during knee flexion at low angles without axial loading.12 Fracture fragment size is inversely correlated with the degree of loading during flexion, implying that a larger fragment is 1
J. Bishop and M. Githens
2 subject to displacement at lower flexion angles.13 These data suggest that even nondisplaced posteromedial fragments are at risk for displacement with early postoperative range of motion and supports the argument for stable fixation. Clinical and radiographic outcomes after treatment of posterior patterns are limited to small observational studies.6,14-30 In the largest series to date, satisfactory articular reduction (o2 mm step or gap) was achieved in 55% of patients with bicondylar tibial plateau fractures treated with combined anterolateral and posteromedial plating. Coronal plane alignment was satisfactory in 90% and sagittal plane alignment was restored accurately in 68% of cases. All patients demonstrated a significant residual dysfunction. Better functional outcomes were significantly correlated with high-quality reduction. Poor functional outcome was strongly correlated to increased fracture severity. Fracture severity was not correlated with reduction quality.14 Sun et al31 successfully combined anterolateral and direct posterior approach and dual plating for posterolateral fractures, reporting no fragment subsidence, no change in limb mechanical axis from immediate-to-final follow-up, no reoperations, and good functional outcomes in a cohort of 41 patients. Additional small series report a broad range of radiographic and functional outcomes after a variety of surgical approaches and fixation strategies. Common complications reported broadly across these series include saphenous nerve injury and superficial wound problems. Loss of reduction, deep infection, and major nerve or vessel injury are reported less frequently.
Treatment Strategies The goals in treating articular fractures of the proximal tibia include restoring knee joint stability, limb mechanical axis, and articular congruity. These goals are achieved through direct anatomical reduction and fixation with interfragmentary compression to gain absolute stability.
Approaches Posteromedial The posteromedial approach affords access to the posterior medial and posterior portions of the medial condyle and is ideal for posteromedial shear and impaction injuries. It can be performed with the patient in the supine position and can be done in conjunction with a standard anterolateral approach for bicondylar patterns. It has also been described in combination with a posterolateral approach.16,17,20,22,23,26,32,33 A longitudinal incision is made 2 cm posterior to the posteromedial border of the tibia. Care must be taken to identify and preserve the saphenous nerve and its branches. The pes anserinus tendons are identified, mobilized, and retracted as necessary. If these tendons continue to obstruct reduction and fixation efforts, they can be tenotomized and repaired at the end of the procedure. The fascia over the medial head of the gastrocnemius is incised and the muscle is retracted laterally so the subperiosteal dissection can then be carried
across the back of the tibia. A bump under the heel is helpful at this stage. A medial submeniscal arthrotomy can be performed as necessary for direct visualization of the articular surface.
Direct Posterior Many iterations of the direct posterior approach have been published.6,27,30,34-40 The patient is positioned prone and a straight incision is made along the border of the medial head of gastrocnemius ending at the level of the joint line. After incising the popliteal fascia, the small saphenous vein is identified in the sulcus between the gastrocnemius heads. The medial gastrocnemius is retracted laterally while the semimembranosus complex is retracted medially without detaching its insertion on the posteromedial tibia. Alternatively, if additional exposure is necessary, the tendon of the medial head of the gastrocnemius can be divided sharply, proximal to the muscle’s blood supply, leaving a cuff for repair. The medial gastrocnemius is then retracted laterally, protecting the neurovascular bundle.30 The upper border of the popliteus muscle is detatched and dissected subperiostally, exposing the fracture. The tibial insertion of the semimembranosus complex can be incised in a subperiosteal fashion, if additional exposure is needed. If further distal exposure is needed, the soleus origin may be partially elevated.
Posterolateral Several variations of a posterolateral approach have been published.19,25,32,41,42 Carlsonet al provides an early description of the posterolateral approach without fibular osteotomy done in concert with a posteromedial approach to address bicondylar fractures with posterolateral and posteromedial shear fragments. After making an s-shaped curvilinear incision over the border of the biceps femoris, the common peroneal nerve is identified and mobilized to allow gentle lateral retraction. The lateral head of the gastrocnemius is retracted medially to expose the underlying soleus. The soleus is elevated from the proximal tibiofibular joint distally and medially, exposing the posterior lateral tibial plateau.32 Although this approach provides an excellent posterior exposure of the lateral plateau, the fibular head limits further lateral exposure and may impede fracture reduction. Solomon et al describe a posterolateral approach utilizing a proximal fibular osteotomy, allowing exposure of the lateral and posterior aspects of the lateral tibial plateau. The skin incision is made along the anterior border of the biceps femoris and carried down the leg. After mobilization of the common peroneal nerve, the fibular head is exposed and an osteotomy is made just distal to the biceps insertion. With retraction of the fibular head proximally, the lateral plateau and joint capsule are clearly exposed.19 Frosch et al developed a surgical approach to the posterolateral tibial fracture, which both protects the soft tissue and allows for good visual control of fracture reduction. The approach involves a lateral arthrotomy for visualizing the joint surface and a posterolateral approach for the fracture reduction and plate fixation, both of which are achieved through a posterolateral skin incision.25 Chen et al have similarly popularized a
Posterior tibial plateau fractures
3 conventional and locked plating for bicondylar fractures with a posteromedial component in composite tibiae, the combination of a conventional anterolateral nonlocking 3.5 mm plate and one-third tubular plate applied posteromedially in buttress mode was superior to locking anterolateral plating in load to failure.43 In a similar composite fracture model, a posteromedial buttress plate was confirmed superior in preventing fragment subsidence to anterior-to-posterior lag screws, limited-contact dynamic compression plate position plate, and an anterolateral locking plate.44 These findings have been substantiated in a cadaveric model.45 The clinical and biomechanical implications of posterolateral tibial plateau fracture fragments are not well understood and the indications for fixation are therefore controversial. These fragments tend to be much smaller than posteromedial fragment, but do share similar morphology.46 Stabilization cannot be achieved with an anterolateral implant and strategies such as direct posterolateral plating, fibular strut placement, and anterior-toposterior screws can be employed.
direct posterolateral approach that obviates the need for a fibular osteotomy.41,42 The patient is positioned prone with a small bump under the ankle to maintain slight knee flexion. A longitudinal skin incision is made along the posterior border of the fibula, beginning 2 cm above the popliteal crease. The subcutaneous tissue and popliteal fascia are incised by sharp dissection and the common peroneal nerve is again identified deep to the biceps femoris tendon. The nerve is mobilized distally until safe lateral retraction is achieved. The lateral sural cutaneous nerve, a branch of the common peroneal nerve is identified and retracted medially. The lateral gastrocnemius muscle is retracted medially. The soleus muscle is then divided from its posterior attachment of the proximal fibula and tibia from lateral to medial as needed to gain exposure of the fracture and retracted medially. The distal dissection is restricted to no more than 5 cm below the articular surface to avoid injury to the anterior tibial artery as it traverses the interosseous membrane. The popliteus muscle is identified and the inferior lateral geniculate artery that passes the muscle surface is ligated. Then, inferior border of the popliteus muscle is dissected and retracted cranially to expose the fracture. The capsule is opened transversely and the meniscus is elevated for intra-articular visualization.
Author’s Preferred Strategy In our practice, the most common indication for a posterior approach is for reduction and fixation of an isolated posteromedial tibial plateau fracture or the posteromedial component of a bicondylar pattern (Fig. 1A-E). It is our preference to do this in the supine position, so that anterolateral and posteromedial approaches can be performed simultaneously
Fixation Posterior coronal plane fractures are vertically unstable making them optimal for buttress plating. In a study comparing
B
A
E
C
F
D
G
Figure 1 (A-E) Plain radiographs and CT images demonstrating an unstable posteromedial tibial plateau fracture in a 63-year-old female injured in a motor vehicle crash. (F and G) Final radiographs after open reduction and internal fixation via a posteromedial approach with posterior and medial buttress plating. CT, computed tomography.
J. Bishop and M. Githens
4 if necessary. Patients with axially unstable bicondylar patterns have frequently been placed into a spanning external fixator for restoration of limb length, alignment, and rotation as well as soft tissue rest. The operative leg is positioned on a foam ramp to facilitate intraoperative fluoroscopy. An inflatable pressure bag can be placed under the ipsilateral hip to allow for internal and external rotation of the limb as the surgeon alternates between the 2 approaches.47 If the fracture is isolated to the posteromedial tibia or if the posteromedial component is the area of most complexity, the c-arm can be set up ipsilateral to the injured limb while the surgical team works from the contralateral side. A bump placed under the patient’s heel allows the calf musculature to fall away, improving exposure. We generally prefer to start on the medial side, as this fracture pattern is frequently simple and amenable to direct anatomical reduction. The approach is performed as described earlier. Reduction is generally best achieved with a combination of valgus, knee extension, and pointed reduction clamp application. A medially based universal distractor can also be helpful. Fixation is generally achieved with one-third tubular plate in buttress mode. In the setting of the sometimes-encountered anteromedial or direct medial fracture fragment, fragmentspecific fixation is employed (Fig. 1F-G). In the case of a truly nondisplaced posteromedial fragment, we occasionally employ
A
E
B
anterior-to-posterior lag-screw fixation. Following posteromedial reduction and fixation, routine anterolateral reduction and fixation is performed as indicated. Less commonly, a bicondylar posterior shearing injury is encountered with significant posteromedial and posterolateral fracture fragments (Fig. 2A-E). In our practice, this is an indication for a prone-direct posterior approach to the tibial plateau as described earlier. Indirect reduction of the medial and lateral articular surfaces is achieved based on anatomical reduction of the posteromedial and posterolateral cortical surfaces and is confirmed using fluoroscopy. Submeniscal arthrotomies can be performed, but direct visualization of the articular surface is limited. Once appropriate reduction has been achieved, routine lag-screw fixation or posterior buttress plating is performed (Fig. 2F-G). We do not routinely perform a posterolateral approach for the treatment of small isolated posterolateral fracture variants (Fig. 3A-E). Our usual strategy is to address these fragments, as indicated, through an anterolateral approach and stabilize them with fragment-specific anterior-to-posterior screws or a fibular strut, if the fragment is of sufficient size (Fig. 3F and G). If satisfactory reduction and fixation cannot be obtained using this strategy, a posterolateral approach can be considered to allow direct access.
C
F
D
G
H
Figure 2 (A-F) Plain radiographs and CT images demonstrating a posterior shearing tibial plateau fracture with extension into the tibial shaft in a 36-year-old male injured in a bicycle crash. Note the unstable partial articular injuries of both the posteromedial (C) and posterolateral (D) plateaus. (G and H) Intraoperative fluoroscopic images after open reduction and internal fixation via a direct posterior approach with posterolateral buttress plating and posteromedial lag-screw fixation. CT, computed tomography.
Posterior tibial plateau fractures
A
5
B
E
F
C
G
D
H
I
Figure 3 (A-E) Plain radiographs and CT images demonstrating a bicondylar tibial plateau fracture with posteromedial and posterolateral involvement in a 36-year-old female with osteogenesis imperfecta injured in a motor vehicle crash. (F and G) Intraoperative fluoroscopic images demonstrating placement of a fibular strut allograft to support the reduced posterolateral impaction. The medial-sided reduction and fixation was performed first via a posteromedial approach. (H and I) Final radiographs in this patient. CT, computed tomography. (Color version of figure is available online.)
Conclusion Posterior tibial plateau fracture patterns are not uncommon injuries. As they are typically unstable fractures requiring fragment-specific fixation, their treatment necessitates a thoughtful approach and fixation strategy. Posteromedial fracture patterns are unstable and should be treated with a direct postermedial approach and buttress plating. Posterior shearing patterns are best treated with a direct posterior approach and fixation of the posteromedial and posterolateral columns. Posterolateral fracture patterns are less common and are amenable to a number of reduction and fixation strategies. As with all-tibial plateau fractures, the goals of treatment are to accurately restore knee joint stability, limb mechanical axis, and articular congruity.
References 1. Yang G, Zhai Q, Zhu Y, et al: The incidence of posterior tibial plateau fracture: An investigation of 525 fractures by using a CT-based classification system. Arch Orthop Trauma Surg 133:929-934, 2013 2. Chen HW, Zhao GS, Wang ZY, et al: [Computed tomographic classification of posterior condylar tibial plateau fractures]. Zhonghua Yi Xue Za Zhi 91:180-184, 2011 3. Chang SM, Zhang YQ, Yao MW, et al: Schatzker type IV medial tibial plateau fractures: A computed tomography-based morphological subclassification. Orthopedics 37:e699-e706, 2014 4. Zhu Y, Yang G, Luo CF, et al: Computed tomography-based threecolumn classification in tibial plateau fractures: Introduction of its utility and assessment of its reproducibility. J Trauma Acute Care Surg 73:731-737, 2012
5. Yang G, Zhu Y, Luo C, et al: Morphological characteristics of Schatzker type IV tibial plateau fractures: A computer tomography based study. Int Orthop 36:2355-2360, 2012 6. Chen HW, Chen CQ, Yi XH: Posterior tibial plateau fracture: A new treatment-oriented classification and surgical management. Int J Clin Exp Med 8:472-479, 2015 7. Barei DP, O’Mara TJ, Taitsman LA, et al: Frequency and fracture morphology of the posteromedial fragment in bicondylar tibial plateau fracture patterns. J Orthop Trauma 22:176-182, 2008 8. Higgins TF, Kemper D, Klatt J: Incidence and morphology of the posteromedial fragment in bicondylar tibial plateau fractures. J Orthop Trauma 23:45-51, 2009 9. Zhai Q, Hu C, Xu Y, et al: Morphologic study of posterior articular depression in Schatzker IV fractures. Orthopedics 38:e124-e128, 2015 10. Sohn HS, Yoon YC, Cho JW, et al: Incidence and fracture morphology of posterolateral fragments in lateral and bicondylar tibial plateau fractures. J Orthop Trauma 29:91-97, 2015 11. Xiang G, Zhi-Jun P, Qiang Z, et al: Morphological characteristics of posterolateral articular fragments in tibial plateau fractures. Orthopedics 36:e1256-e1261, 2013 12. Cuéllar VG, Martinez D, Immerman I, et al: A biomechanical study of posteromedial tibial plateau fracture stability: Do they all require fixation? J Orthop Trauma 29(7):325-330, 2015 13. Immerman I, Bechtel C, Yildirim G, et al: Stability of the posteromedial fragment in a tibial plateau fracture. J Knee Surg 26:117-126, 2013 14. Barei DP, Nork SE, Mills WJ, et al: Functional outcomes of severe bicondylar tibial plateau fractures treated with dual incisions and medial and lateral plates. J Bone Joint Surg Am 88:1713-1721, 2006 15. Luo CF, Sun H, Zhang B, et al: Three-column fixation for complex tibial plateau fractures. J Orthop Trauma 24:683-692, 2010 16. Liu Z, Li G, Yang Y, et al: [Three-column plate internal fixation for the treatment of complex tibial plateau fracture through antero-midline and postero-medial approaches]. Zhongguo Gu Shang 27:961-964, 2014
6 17. Potocnik P, Acklin YP, Sommer C: Operative strategy in postero-medial fracture-dislocation of the proximal tibia. Injury 42:1060-1065, 2011 18. Carlson DA: Posterior bicondylar tibial plateau fractures. J Orthop Trauma 19:73-78, 2005 19. Solomon LB, Stevenson AW, Baird RP, et al: Posterolateral transfibular approach to tibial plateau fractures: Technique, results, and rationale. J Orthop Trauma 24:505-514, 2010 20. Chang SM, Wang X, Zhou JQ, et al: Posterior coronal plating of bicondylar tibial plateau fractures through posteromedial and anterolateral approaches in a healthy floating supine position. Orthopedics 35:583-588, 2012 21. Chang SM, Hu SJ, Zhang YQ, et al: A surgical protocol for bicondylar fourquadrant tibial plateau fractures. Int Orthop 38:2559-2564, 2014 22. Ren WF, Zhang NN, Zhu YY: [Medial plus anterolateral approaches for the treatment of tibial plateau fractures involving three columns]. Zhongguo Gu Shang 26:768-771, 2013 23. Chen HW, Zhao GS, Wang ZY, et al: Operative treatment for posteromedial condylar split fracture of tibial plateau. Zhongguo Gu Shang 25:190-193, 2012 24. Meng DP, Ye TW, Chen AM: An osteotomy anterolateral approach for lateral tibial plateau fractures merged with relatively simple and intact posterolateral corner displacement. J Orthop Surg Res 9:26, 2014 25. Frosch KH, Balcarek P, Walde T, et al: A new posterolateral approach without fibula osteotomy for the treatment of tibial plateau fractures. J Orthop Trauma 24:515-520, 2010 26. Berber R, Lewis CP, Copas D, et al: Postero-medial approach for complex tibial plateau injuries with a postero-medial or postero-lateral shear fragment. Injury 45:757-765, 2014 27. Galla M, Riemer C, Lobenhoffer P: [Direct posterior approach for the treatment of posteromedial tibial head fractures]. Oper Orthop Traumatol 21:51-64, 2009 28. Fang Y, Ma K, Yang T, et al: [Effectiveness of posterior approaches for treatment of posterior coronal fracture]. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 25:1082-1086, 2011 29. Brunner A, Honigmann P, Horisberger M, et al: Open reduction and fixation of medial Moore type II fractures of the tibial plateau by a direct dorsal approach. Arch Orthop Trauma Surg 129:1233-1238, 2009 30. Bhattacharyya T, McCarty LP, Harris MB, et al: The posterior shearing tibial plateau fracture: Treatment and results via a posterior approach. J Orthop Trauma 19:305-310, 2005 31. Sun H, Zhai QL, Xu YF, et al: Combined approaches for fixation of Schatzker type II tibial plateau fractures involving the posterolateral column: A prospective observational cohort study. Arch Orthop Trauma Surg 135:209-221, 2015 32. Carlson DA: Bicondylar fracture of the posterior aspect of the tibial plateau. A case report and a modified operative approach. J Bone Joint Surg Am 80:1049-1052, 1998
J. Bishop and M. Githens 33. Chen Z, Dai Z, Yang L, et al: [Treatment of Schatzker V/VI tibial plateau fracture involved posteromedial condyle through combined approach]. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 23:1319-1322, 2009 34. Muhm M, Schneider P, Ruffing T, et al: [Posterocentral approach to the posterior tibial plateau. Reconstruction of tibial plateau fractures and avulsions of the posterior cruciate ligament]. Unfallchirurg 117:813-821, 2014 35. Muhm M, Winkler H: The posterocentral approach to the posterior tibial plateau. Oper Orthop Traumatol 27:80-93, 2015 36. Chen CW, Chen L, Pan ZE, et al: [Open reduction and internal fixation via a posterior approach for posterior fractures of tibial plateau]. Zhongguo Gu Shang 25:561-565, 2012 37. Alpert JM, McCarty LP, Bach BR: The direct posterior approach to the knee: Surgical and anatomic approach. J Knee Surg 21:44-49, 2008 38. Connolly JF: The posterior shearing tibial plateau fracture: Treatment and results via a posterior approach. J Orthop Trauma 19:508, 2005. [author reply] 39. Lobenhoffer P, Gerich T, Bertram T, et al: [Particular posteromedial and posterolateral approaches for the treatment of tibial head fractures]. Unfallchirurg 100:957-967, 1997 40. De Boeck H, Opdecam P: Posteromedial tibial plateau fractures. Operative treatment by posterior approach. Clin Orthop Relat Res 320:125-128, 1995 41. Chang SM, Zheng HP, Li HF, et al: Treatment of isolated posterior coronal fracture of the lateral tibial plateau through posterolateral approach for direct exposure and buttress plate fixation. Arch Orthop Trauma Surg 129:955-962, 2009 42. Wang SQ, Gao YS, Wang JQ, et al: Surgical approach for highenergy posterior tibial plateau fractures. Indian J Orthop 45:125-131, 2011 43. Yoo BJ, Beingessner DM, Barei DP: Stabilization of the posteromedial fragment in bicondylar tibial plateau fractures: A mechanical comparison of locking and nonlocking single and dual plating methods. J Trauma 69:148-155, 2010 44. Zeng ZM, Luo CF, Putnis S, et al: Biomechanical analysis of posteromedial tibial plateau split fracture fixation. Knee 18:51-54, 2011 45. Higgins TF, Klatt J, Bachus KN: Biomechanical analysis of bicondylar tibial plateau fixation: How does lateral locking plate fixation compare to dual plate fixation? J Orthop Trauma 21:301-306, 2007 46. Sassoon AA, Torchia ME, Cross WW, et al: Fibular shaft allograft support of posterior joint depression in tibial plateau fractures. J Orthop Trauma 28:e169-e175, 2014 47. Abrams GD, Bishop JA: Use of an inflatable pressure bag bump for medial and lateral operative approaches to the lower leg. Foot Ankle Int 33:795-797, 2012
KEYWORDS Tibial plateau, trauma, surgical technique
Introduction
C
oronal plane fractures involving the posterior tibial plateau are increasingly recognized as injuries that require unique treatment strategies. Care must be given to the diagnosis and management of these injuries as they are easily overlooked, yet unstable patterns that necessitate fracturespecific surgical approaches and fixation strategies. Posterior fractures are rarely found in isolation. They are typically a result of a high-energy injury and are found in combination with additional fractures through the tibial plateau.1 Although the Schatzker and Moore classification schemes are frequently used to describe tibial plateau fractures, they do not specifically address posterior coronal plane patterns. Increased recent attention to these injury patterns has generated modifications of these classification systems as well as alternative classifications.2-6 Careful scrutiny of reformatted computed tomography scans and their 3-dimensional Department of Orthopaedic Surgery, Stanford University Medical Center, Redwood City, CA. Conflict of interest: Dr Bishop serves as a consultant for Globus Medical and receives royalties from Innomed. Dr Githens has no conflicts to report. *Address reprint requests to Julius Bishop, MD, Department of Orthopaedic Surgery, Stanford University Medical Center, 450 Broadway St, MC 6342, Redwood City, CA 94063. E-mail: [email protected]
http://dx.doi.org/10.1053/j.oto.2015.08.004 1048-6666//& 2015 Elsevier Inc. All rights reserved.
renderings is important in understanding these patters, as the fracture location and pattern would dictate the surgical approach and fixation strategy. Although indications for posterior fixation are controversial, there is a growing body of evidence to support direct anatomical reduction and fragment-specific fixation.
Clinical Relevance Posterior tibial plateau fractures are not uncommon. A clinically significant posteromedial fragment has been observed in 30%-59% of bicondylar patterns.7,8 These fragments involve approximately a quarter of the total tibial plateau surface and are significantly displaced in half of the cases.7,8 Posteromedial articular depression has also been observed in 50% of medial tibial plateau fractures (Schatzker IV patterns).9 Posterolateral fragments are the least common but still occur in up to 44% of fractures. These fragments tend to be smaller, involving an average of 15% of the surface area of the plateau.10,11 Cadaveric models confirm the unstable nature of these patterns. Displacement of the posteromedial fragment occurs during knee flexion at low angles without axial loading.12 Fracture fragment size is inversely correlated with the degree of loading during flexion, implying that a larger fragment is 1
J. Bishop and M. Githens
2 subject to displacement at lower flexion angles.13 These data suggest that even nondisplaced posteromedial fragments are at risk for displacement with early postoperative range of motion and supports the argument for stable fixation. Clinical and radiographic outcomes after treatment of posterior patterns are limited to small observational studies.6,14-30 In the largest series to date, satisfactory articular reduction (o2 mm step or gap) was achieved in 55% of patients with bicondylar tibial plateau fractures treated with combined anterolateral and posteromedial plating. Coronal plane alignment was satisfactory in 90% and sagittal plane alignment was restored accurately in 68% of cases. All patients demonstrated a significant residual dysfunction. Better functional outcomes were significantly correlated with high-quality reduction. Poor functional outcome was strongly correlated to increased fracture severity. Fracture severity was not correlated with reduction quality.14 Sun et al31 successfully combined anterolateral and direct posterior approach and dual plating for posterolateral fractures, reporting no fragment subsidence, no change in limb mechanical axis from immediate-to-final follow-up, no reoperations, and good functional outcomes in a cohort of 41 patients. Additional small series report a broad range of radiographic and functional outcomes after a variety of surgical approaches and fixation strategies. Common complications reported broadly across these series include saphenous nerve injury and superficial wound problems. Loss of reduction, deep infection, and major nerve or vessel injury are reported less frequently.
Treatment Strategies The goals in treating articular fractures of the proximal tibia include restoring knee joint stability, limb mechanical axis, and articular congruity. These goals are achieved through direct anatomical reduction and fixation with interfragmentary compression to gain absolute stability.
Approaches Posteromedial The posteromedial approach affords access to the posterior medial and posterior portions of the medial condyle and is ideal for posteromedial shear and impaction injuries. It can be performed with the patient in the supine position and can be done in conjunction with a standard anterolateral approach for bicondylar patterns. It has also been described in combination with a posterolateral approach.16,17,20,22,23,26,32,33 A longitudinal incision is made 2 cm posterior to the posteromedial border of the tibia. Care must be taken to identify and preserve the saphenous nerve and its branches. The pes anserinus tendons are identified, mobilized, and retracted as necessary. If these tendons continue to obstruct reduction and fixation efforts, they can be tenotomized and repaired at the end of the procedure. The fascia over the medial head of the gastrocnemius is incised and the muscle is retracted laterally so the subperiosteal dissection can then be carried
across the back of the tibia. A bump under the heel is helpful at this stage. A medial submeniscal arthrotomy can be performed as necessary for direct visualization of the articular surface.
Direct Posterior Many iterations of the direct posterior approach have been published.6,27,30,34-40 The patient is positioned prone and a straight incision is made along the border of the medial head of gastrocnemius ending at the level of the joint line. After incising the popliteal fascia, the small saphenous vein is identified in the sulcus between the gastrocnemius heads. The medial gastrocnemius is retracted laterally while the semimembranosus complex is retracted medially without detaching its insertion on the posteromedial tibia. Alternatively, if additional exposure is necessary, the tendon of the medial head of the gastrocnemius can be divided sharply, proximal to the muscle’s blood supply, leaving a cuff for repair. The medial gastrocnemius is then retracted laterally, protecting the neurovascular bundle.30 The upper border of the popliteus muscle is detatched and dissected subperiostally, exposing the fracture. The tibial insertion of the semimembranosus complex can be incised in a subperiosteal fashion, if additional exposure is needed. If further distal exposure is needed, the soleus origin may be partially elevated.
Posterolateral Several variations of a posterolateral approach have been published.19,25,32,41,42 Carlsonet al provides an early description of the posterolateral approach without fibular osteotomy done in concert with a posteromedial approach to address bicondylar fractures with posterolateral and posteromedial shear fragments. After making an s-shaped curvilinear incision over the border of the biceps femoris, the common peroneal nerve is identified and mobilized to allow gentle lateral retraction. The lateral head of the gastrocnemius is retracted medially to expose the underlying soleus. The soleus is elevated from the proximal tibiofibular joint distally and medially, exposing the posterior lateral tibial plateau.32 Although this approach provides an excellent posterior exposure of the lateral plateau, the fibular head limits further lateral exposure and may impede fracture reduction. Solomon et al describe a posterolateral approach utilizing a proximal fibular osteotomy, allowing exposure of the lateral and posterior aspects of the lateral tibial plateau. The skin incision is made along the anterior border of the biceps femoris and carried down the leg. After mobilization of the common peroneal nerve, the fibular head is exposed and an osteotomy is made just distal to the biceps insertion. With retraction of the fibular head proximally, the lateral plateau and joint capsule are clearly exposed.19 Frosch et al developed a surgical approach to the posterolateral tibial fracture, which both protects the soft tissue and allows for good visual control of fracture reduction. The approach involves a lateral arthrotomy for visualizing the joint surface and a posterolateral approach for the fracture reduction and plate fixation, both of which are achieved through a posterolateral skin incision.25 Chen et al have similarly popularized a
Posterior tibial plateau fractures
3 conventional and locked plating for bicondylar fractures with a posteromedial component in composite tibiae, the combination of a conventional anterolateral nonlocking 3.5 mm plate and one-third tubular plate applied posteromedially in buttress mode was superior to locking anterolateral plating in load to failure.43 In a similar composite fracture model, a posteromedial buttress plate was confirmed superior in preventing fragment subsidence to anterior-to-posterior lag screws, limited-contact dynamic compression plate position plate, and an anterolateral locking plate.44 These findings have been substantiated in a cadaveric model.45 The clinical and biomechanical implications of posterolateral tibial plateau fracture fragments are not well understood and the indications for fixation are therefore controversial. These fragments tend to be much smaller than posteromedial fragment, but do share similar morphology.46 Stabilization cannot be achieved with an anterolateral implant and strategies such as direct posterolateral plating, fibular strut placement, and anterior-toposterior screws can be employed.
direct posterolateral approach that obviates the need for a fibular osteotomy.41,42 The patient is positioned prone with a small bump under the ankle to maintain slight knee flexion. A longitudinal skin incision is made along the posterior border of the fibula, beginning 2 cm above the popliteal crease. The subcutaneous tissue and popliteal fascia are incised by sharp dissection and the common peroneal nerve is again identified deep to the biceps femoris tendon. The nerve is mobilized distally until safe lateral retraction is achieved. The lateral sural cutaneous nerve, a branch of the common peroneal nerve is identified and retracted medially. The lateral gastrocnemius muscle is retracted medially. The soleus muscle is then divided from its posterior attachment of the proximal fibula and tibia from lateral to medial as needed to gain exposure of the fracture and retracted medially. The distal dissection is restricted to no more than 5 cm below the articular surface to avoid injury to the anterior tibial artery as it traverses the interosseous membrane. The popliteus muscle is identified and the inferior lateral geniculate artery that passes the muscle surface is ligated. Then, inferior border of the popliteus muscle is dissected and retracted cranially to expose the fracture. The capsule is opened transversely and the meniscus is elevated for intra-articular visualization.
Author’s Preferred Strategy In our practice, the most common indication for a posterior approach is for reduction and fixation of an isolated posteromedial tibial plateau fracture or the posteromedial component of a bicondylar pattern (Fig. 1A-E). It is our preference to do this in the supine position, so that anterolateral and posteromedial approaches can be performed simultaneously
Fixation Posterior coronal plane fractures are vertically unstable making them optimal for buttress plating. In a study comparing
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Figure 1 (A-E) Plain radiographs and CT images demonstrating an unstable posteromedial tibial plateau fracture in a 63-year-old female injured in a motor vehicle crash. (F and G) Final radiographs after open reduction and internal fixation via a posteromedial approach with posterior and medial buttress plating. CT, computed tomography.
J. Bishop and M. Githens
4 if necessary. Patients with axially unstable bicondylar patterns have frequently been placed into a spanning external fixator for restoration of limb length, alignment, and rotation as well as soft tissue rest. The operative leg is positioned on a foam ramp to facilitate intraoperative fluoroscopy. An inflatable pressure bag can be placed under the ipsilateral hip to allow for internal and external rotation of the limb as the surgeon alternates between the 2 approaches.47 If the fracture is isolated to the posteromedial tibia or if the posteromedial component is the area of most complexity, the c-arm can be set up ipsilateral to the injured limb while the surgical team works from the contralateral side. A bump placed under the patient’s heel allows the calf musculature to fall away, improving exposure. We generally prefer to start on the medial side, as this fracture pattern is frequently simple and amenable to direct anatomical reduction. The approach is performed as described earlier. Reduction is generally best achieved with a combination of valgus, knee extension, and pointed reduction clamp application. A medially based universal distractor can also be helpful. Fixation is generally achieved with one-third tubular plate in buttress mode. In the setting of the sometimes-encountered anteromedial or direct medial fracture fragment, fragmentspecific fixation is employed (Fig. 1F-G). In the case of a truly nondisplaced posteromedial fragment, we occasionally employ
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anterior-to-posterior lag-screw fixation. Following posteromedial reduction and fixation, routine anterolateral reduction and fixation is performed as indicated. Less commonly, a bicondylar posterior shearing injury is encountered with significant posteromedial and posterolateral fracture fragments (Fig. 2A-E). In our practice, this is an indication for a prone-direct posterior approach to the tibial plateau as described earlier. Indirect reduction of the medial and lateral articular surfaces is achieved based on anatomical reduction of the posteromedial and posterolateral cortical surfaces and is confirmed using fluoroscopy. Submeniscal arthrotomies can be performed, but direct visualization of the articular surface is limited. Once appropriate reduction has been achieved, routine lag-screw fixation or posterior buttress plating is performed (Fig. 2F-G). We do not routinely perform a posterolateral approach for the treatment of small isolated posterolateral fracture variants (Fig. 3A-E). Our usual strategy is to address these fragments, as indicated, through an anterolateral approach and stabilize them with fragment-specific anterior-to-posterior screws or a fibular strut, if the fragment is of sufficient size (Fig. 3F and G). If satisfactory reduction and fixation cannot be obtained using this strategy, a posterolateral approach can be considered to allow direct access.
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Figure 2 (A-F) Plain radiographs and CT images demonstrating a posterior shearing tibial plateau fracture with extension into the tibial shaft in a 36-year-old male injured in a bicycle crash. Note the unstable partial articular injuries of both the posteromedial (C) and posterolateral (D) plateaus. (G and H) Intraoperative fluoroscopic images after open reduction and internal fixation via a direct posterior approach with posterolateral buttress plating and posteromedial lag-screw fixation. CT, computed tomography.
Posterior tibial plateau fractures
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Figure 3 (A-E) Plain radiographs and CT images demonstrating a bicondylar tibial plateau fracture with posteromedial and posterolateral involvement in a 36-year-old female with osteogenesis imperfecta injured in a motor vehicle crash. (F and G) Intraoperative fluoroscopic images demonstrating placement of a fibular strut allograft to support the reduced posterolateral impaction. The medial-sided reduction and fixation was performed first via a posteromedial approach. (H and I) Final radiographs in this patient. CT, computed tomography. (Color version of figure is available online.)
Conclusion Posterior tibial plateau fracture patterns are not uncommon injuries. As they are typically unstable fractures requiring fragment-specific fixation, their treatment necessitates a thoughtful approach and fixation strategy. Posteromedial fracture patterns are unstable and should be treated with a direct postermedial approach and buttress plating. Posterior shearing patterns are best treated with a direct posterior approach and fixation of the posteromedial and posterolateral columns. Posterolateral fracture patterns are less common and are amenable to a number of reduction and fixation strategies. As with all-tibial plateau fractures, the goals of treatment are to accurately restore knee joint stability, limb mechanical axis, and articular congruity.
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