ORIGINAL ARTICLE The Risk of Injury to the Anterior Tibial Artery in the Posterolateral Approach to the Tibia Plateau: A Cadaver Study Nima Heidari, MBBS, MRCS(Eng), MSc, FRCS(Tr&Orth),* Surjit Lidder, BSc(Hons), MBBS, MRCS(Eng), Wolfgang Grechenig, MD, Norbert P. Tesch, MD, and Annelie M. Weinberg, MDk Background: Posterolateral tibial plateau shear fractures often require buttress plating, which can be performed through a posterolateral approach. The purpose of this study was to provide accurate data about the inferior limit of dissection. Methods: Forty unpaired cadaver adult lower limbs were used. The anterior tibial artery was identified because it coursed through the interosseous membrane. The perpendicular distance from the lateral joint line and fibula head to this landmark was measured. Results: The anterior tibial artery coursed through the interosseous membrane at 46.3 6 9.0 mm (range 27 62 mm) distal to the lateral tibial plateau and 35.7 6 9.0 mm (range 17 50 mm) distal to the fibula head. Conclusions: Displaced posterolateral tibial plateau fractures require anatomic reduction and stabilization with a buttress plate. This can be achieved by gaining access to the posterolateral tibial cortex. The distal limit of this dissection can be as little as 27 mm distal to the lateral tibial plateau. Dissection in this region should be carried out with caution. Key Words: knee, tibial plateau, fracture, posterolateral, posterolateral approach, anterior tibial artery (J Orthop Trauma 2013;27:221 225) INTRODUCTION Fractures of the tibial plateau are uncommon with those affecting the posterolateral tibial plateau accounting for approximately 7%. 1 Operative fixation through an anterolateral approach has been described; however, there is a biomechanical advantage of a posterolateral plate position. Several approaches have been described for the posterolateral tibial plateau 2 8 with authors deliberating over the merits of each. Accepted for publication August 30, 2012. From the *Department of Trauma and Orthopaedics, Royal London Hospital, London, United Kingdom; Department of Trauma and Orthopaedics, Eastbourne District General Hospital, East Sussex, United Kingdom; Department of Traumatology, Medical University of Graz, Graz, Austria; Institute of Anatomy, Medical University of Graz, Graz, Austria; and kdepartment of Pediatric and Adolescent Surgery, Medical University of Graz, Graz, Austria. The authors have no financial disclosures or conflicts of interest to declare. Reprints: Mr Nima Heidari, MBBS, MRCS(Eng), MSc, FRCS(Tr&Orth), Department of Trauma and Orthopaedics, Royal London Hospital, Whitechapel, London E1 1BB, United Kingdom (e-mail: n.heidari@gmail.com). Copyright 2013 by Lippincott Williams & Wilkins The extent of distal dissection through the posterolateral approach is often stated as 5 cm from the tibial plateau where the anterior tibial artery perforates through the interosseous membrane 5 ; however, no published anatomic studies support this measurement. This study aims to provide accurate data about the safe inferior limit of dissection for the posterolateral approach by providing measurements of the anterior tibial artery from the lateral joint line and fibula head to where it pierces the interosseous membrane. MATERIALS AND METHODS Forty unpaired, white adult lower limbs (20 left and 20 right) preserved using the method of Thiel were used for this study. 9 None of the limbs had signs of previous injury, abnormality, or disease. The mean age of the donors had been 71 years (range, 44 84 years) at the time of death. Each lower limb was dissected using the posterolateral approach to the proximal tibia, as described by Frosch et al. 7 The skin and superficial fascia were removed from the knee leaving the deep fascia intact. First, the common peroneal nerve was identified on the posterior border of biceps femoris (Fig. 1). It was followed from the apex of the popliteal fossa to the fibular neck. The lateral border of the lateral head of gastrocnemius muscle was identified from its origin on the posterior aspect of the lateral femoral condyle distally (Fig. 2). The anatomic plane between it and the soleus muscle was developed by blunt dissection. This brought the tendon of the popliteus muscle and the belly of the soleus muscle along its fibular attachment into view (Fig. 3). In this plane, care must be taken to identify and ligate the inferolateral genicular branch of the popliteal artery. Once this was done, the popliteus muscle was mobilized subperiosteally either proximally or its tendon divided between stay-sutures so that it could be repaired during closure (Fig. 4). The soleus muscle was released from its origin on the posterior aspect of the fibula and retracted medially. This brought the anterior tibial vessels into view (Fig. 5). Occasionally, muscular branches of the popliteal artery require ligation for the muscle to be mobilized more easily. Care must be taken when releasing the soleus from the medial border of fibula because the attachment is quite fibrous at this location and vigorous tissue handling can injure the anterior tibial vessels. Just distal to the inferior border of popliteus, the anterior tibial artery courses anteriorly and pierces the interosseous J Orthop Trauma Volume 27, Number 4, April 2013 www.jorthotrauma.com 221
Heidari et al J Orthop Trauma Volume 27, Number 4, April 2013 FIGURE 1. Posterior aspect of the right knee with skin and superficial fascia removed. Biceps femoris muscle (b), common peroneal nerve (c), lateral head of gastrocnemius muscle (g) and soleus muscle (s). membrane. This defines the most distal limit of this dissection. Once the anterior tibial artery was identified as it coursed through the interosseous membrane, a posterior arthrotomy was performed locating the joint line (Fig. 6). Perpendicular measurements were made from the posterior limit of the articular surface of the lateral tibial plateau and fibula head (Fig. 7) to the position where the anterior tibial artery pierced the interosseous membrane. All distances were measured using a Vernier caliper and recorded in millimeters. RESULTS The anterior tibial artery coursed through the interosseous membrane at 46.3 6 9.0 mm (range 27 62 mm) distal to the lateral tibial plateau and 35.7 6 9.0 mm (range 17 50 mm) distal to the fibula head. In 6 of the 40 (15%) specimens, the distance from the lateral tibial plateau to the perforation of the anterior tibial artery was 27 35 mm. In 13 of 40 (32.5%), the distance was 36 45 mm. In 13 of 40 (32.5%), FIGURE 2. The lateral border of the lateral head of gastrocnemius muscle (g) was identified from its origin on the posterior aspect of the lateral femoral condyle distally and common peroneal nerve (c) exposed distally in the soleus muscle (s). Biceps femoris muscle (b). the distance was 46 55 mm, and in the last 8 of 40 (20%), the distance was 56 62 mm. There was no difference between right- or left-sided knees [anterior tibial artery distal to lateral tibial plateau; right: 44.8 6 8.5 mm (range 30 60 mm), left: 47.8 6 9.3 mm (range 27 62 mm); and distal to fibula head; right: 34.4 6 8.6 mm (range 18 49 mm), left: 37.0 6 9.3 mm (range 17 50 mm)] (Fig. 8). DISCUSSION Posterolateral tibial plateau fractures are uncommon. They are caused by a valgus and axial compressive force, with the knee in flexion. This results in a shearing force exerted on the posterolateral tibial plateau by the lateral femoral condyle. Isolated posterolateral plateau injuries are difficult to asses radiographically on anteroposterior views and full assessment of the fracture morphology requires 222 www.jorthotrauma.com Ó 2013 Lippincott Williams & Wilkins
J Orthop Trauma Volume 27, Number 4, April 2013 Risk of Injury to the Anterior Tibial Artery FIGURE 3. The anatomic plane between the gastrocnemius (g) and soleus (s) muscles was developed by blunt dissection. This brought the tendon of popliteus muscle (p), the belly of soleus muscle, and anterior tibial (AT) artery into view. Biceps femoris muscle (b) and common peroneal nerve (c). a computed tomography. 10 Most tibial plateau fractures are partial articular OTA type B and involve the anterolateral (Schatzker type I-III) or posteromedial (Schatzker type IV) quadrants. 11 Posterolateral tibial plateau injuries may occur in isolation or in combination with posteromedial or anterolateral tibial plateau fractures. Anatomic reduction of these intra-articular fractures is advocated to reduce painful intraarticular malunions. 12 Up to 26% of reduced fractures may still have an articular step and angular deformity. 7 For isolated posterolateral tibial plateau fractures, a buttress plate affords optimal biomechanical fixation. A number of approaches have been described for the operative reduction and fixation of isolated or combined posterolateral tibial plateau fractures. 3,5,7,13 When there is a combination of posteromedial and posterolateral shear fractures, an extensile posteromedial approach has been described. 10 To avoid injury to the neurovascular bundle in the popliteal space, Luo et al 10 suggested that all the dissection from medial to lateral should be performed beneath the popliteus muscle in the proximal part of the approach. FIGURE 4. The popliteus muscle (p) can be mobilized subperiosteally either proximally or its tendon divided between stay-sutures so that it may be repaired during closure. Biceps femoris muscle (b), common peroneal nerve (c), lateral head of gastrocnemius muscle (g), soleus muscle (s), and anterior tibial artery (AT). Normal anatomic variation in the popliteal artery and its branches can, however, provide a challenge during this surgical dissection. The anterior tibial artery branches quite proximally from the popliteal artery trunk at the proximal border of popliteus muscle in 2.3% of the cases. 14 In a further 0.9% of the cases, the peroneal artery arises from the high branching anterior tibial artery. 14 In an unknown proportion of these anatomic variants, the anterior tibial artery lies deep to the popliteus muscle, in direct contact with the posterior tibial cortex. 14 The rarity of these injuries means that the results of fixation of these fractures are restricted to small case series. 13 Frosch et al 7 described a posterolateral approach without fibula osteotomy. This technique permits minimal fracture fragment dissection with preservation of the posterolateral ligaments. With all of the techniques described, however, the distal limit of dissection is the location that the anterior tibial artery perforates the interosseous membrane. This distance has not been previously described with reference to Ó 2013 Lippincott Williams & Wilkins www.jorthotrauma.com 223
Heidari et al J Orthop Trauma Volume 27, Number 4, April 2013 FIGURE 5. The soleus muscle (s) is released from its origin on the posterior aspect of the fibula (f) and retracted medially. The anterior tibial (AT) vessels are brought into view. Biceps femoris muscle (b), common peroneal nerve (c), lateral head of gastrocnemius muscle (g), and popliteal muscle (p). anatomic data. The anterior tibial artery supplies the muscles of the anterior compartment of the leg and the overlying skin. 15 Iatrogenic injury to it at the level of trifurcation can result in ischemic necrosis of the muscles of this compartment and skin loss. This cadaveric study shows that the safe zone of distal exposure through which fracture manipulation and safe application of a buttress plate can be performed maybe as little as 27 mm distal to the lateral tibial plateau. This was the case in 1 of the 40 specimens investigated for this study, but in a further 5, the distance of the lateral tibial plateau to the perforation of the anterior tibial artery was less than 35 mm. In these challenging cases, a proximal fibular osteotomy as described by Lobenhoffer et al 3 can be performed. However, this does not necessarily improve the distal extent of the dissection and carries with it the associated risks of injury to the FIGURE 6. The anterior tibial (AT) artery was identified as it coursed through the interosseous membrane. The popliteal muscle (p) is reflected medially to identify the lateral tibial plateau (t). Biceps femoris muscle (b), common peroneal nerve (c), lateral head of gastrocnemius muscle (g), fibula (f), and soleus muscle (s). common peroneal nerve and further compromise of the already injured posterolateral corner soft tissues. There is also a small risk of nonunion of this osteotomy. Luo et al 10 have described an extensile posteromedial approach where the posterolateral cortex of the proximal tibia can be exposed by subperiosteal dissection deep to the popliteus muscle. These authors also caution against dissecting too far distally and laterally toward the interosseous membrane because the anterior tibial artery may be damaged. Additionally, ultrasonography studies have shown that in up to 6% of cases, the anterior tibial artery has a more proximal origin. 16 It originates proximal to the popliteus muscle and passes beneath it in contact with the posterior tibial cortex, leaving it unprotected during elevation of the popliteus muscle from the posterior tibial cortex. In conclusion, dissection in this region should be carried out with caution. A good understanding of the surgical anatomy of this region and the morphology of the fracture are essential for a successful outcome. 224 www.jorthotrauma.com Ó 2013 Lippincott Williams & Wilkins
J Orthop Trauma Volume 27, Number 4, April 2013 Risk of Injury to the Anterior Tibial Artery FIGURE 8. Bar graph and diagram showing perpendicular distance of anterior tibial artery perforating the interosseous membrane (X) from the lateral tibial plateau. FIGURE 7. Vascular anatomy of the posterior left knee. Popliteal artery (P), lateral superior genicular artery (a), medial superior genicular artery (b), lateral inferior genicular artery (c), medial inferior genicular artery (d), anterior tibial (AT) artery. Perpendicular measurements from lateral joint line (A) and fibula head (B) to anterior tibial artery. REFERENCES 1. Partenheimer A, Gosling T, Muller M, et al. Management of bicondylar fractures of the tibial plateau with unilateral fixed-angle plate fixation [Article in German]. Unfallchirurg. 2007;110:675 683. 2. Carlson DA. Posterior bicondylar tibial plateau fractures. J Orthop Trauma. 2005;19:73 78. 3. Lobenhoffer P, Gerich T, Bertram T, et al. Particular posteromedial and posterolateral approaches for the treatment of tibial head fractures [Article in German]. Unfallchirurg. 1997;100:957 967. 4. Alpert JM, McCarty LP, Bach BR Jr. The posterolateral corner of the knee: anatomic dissection and surgical approach. JKneeSurg.2008;21:50 54. 5. 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. 2009;129:955 962. 6. Trickey EL. Rupture of the posterior cruciate ligament of the knee. J Bone Joint Surg Br. 1968;50:334 341. 7. 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. 2010;24:515 520. 8. Tao J, Hang DH, Wang QG, et al. The posterolateral shearing tibial plateau fracture: treatment and results via a modified posterolateral approach. Knee. 2008;15:473 479. 9. Thiel W. The preservation of the whole corpse with natural color [Article in German]. Ann Anat. 1992;174:185 195. 10. Luo CF, Sun H, Zhang B, et al. Three-column fixation for complex tibial plateau fractures. J Orthop Trauma. 2010;24:683 692. 11. Chang SM. Selection of surgical approaches to the posterolateral tibial plateau fracture by its combination patterns. J Orthop Trauma. 2011;25:e32 e33. 12. Stevens DG, Beharry R, McKee MD, et al. The long-term functional outcome of operatively treated tibial plateau fractures. J Orthop Trauma. 2001;15:312 320. 13. Solomon LB, Stevenson AW, Baird RP, et al. Posterolateral transfibular approach to tibial plateau fractures: technique, results, and rationale. J Orthop Trauma. 2010;24:505 514. 14. Mauro MA, Jaques PF, Moore M. The popliteal artery and its branches: embryologic basis of normal and variant anatomy. AJR Am J Roentgenol. 1988;150:435 437. 15. Attinger CE, Evans KK, Bulan E, et al. Angiosomes of the foot and ankle and clinical implications for limb salvage: reconstruction, incisions, and revascularization. Plast Reconstr Surg. 2006;117:261S 293S. 16. Tindall AJ, Shetty AA, James KD, et al. Prevalence and surgical significance of a high-origin anterior tibial artery. J Orthop Surg (Hong Kong). 2006;14:13 16. Ó 2013 Lippincott Williams & Wilkins www.jorthotrauma.com 225