Isolated posterior high ankle sprain: a report of three cases

Journal of Orthopaedic Surgery 2013;21(3):391-5 Isolated posterior high ankle sprain: a report of three cases Rajesh Botchu, 1 Patricia Allen, 2 Winston J Rennie 1 1 Department of Musculoskeletal Radiology, Leicester Royal Infirmary, Leicester, United Kingdom 2 Department of Foot and Ankle, Leicester Royal Infirmary, Leicester, United Kingdom ABSTRACT High ankle sprains are difficult to diagnose and account for 10% of all ankle sprains. A high index of suspicion is essential for diagnosis. High ankle sprains are managed symptomatically, with prolonged rehabilitation. The posterior inferior tibiofibular ligament is the strongest syndesmotic ligament; isolated injury of it is rare. We present 3 cases of isolated posterior high ankle sprain and discuss the relevant anatomy, mechanism of injury, and management. Key words: ankle injuries; ankle joint INTRODUCTION Ligament injuries of the ankle are common. 1 The daily incidence is 23 000 in the USA, 5600 in the UK, and 1600 in the Netherlands. 2 Syndesmostic injuries, also known as high ankle sprains, are a subset of these and should be treated appropriately to decrease morbidity and enable a rapid return to sport and other activities. In high ankle sprains, the anterior inferior tibiofibular ligament (AITFL) is usually ruptured. The posterior inferior tibiofibular ligament (PITFL) is the strongest of the syndesmotic ligaments and hence isolated injury of it is rare. We present 3 patients with isolated PITFL injury and discuss the relevant anatomy, mechanism of injury, and management. CASE REPORTS Patient 1 In February 2010, a 36-year-old man presented with an 8-month history of dull posterior and posterolateral pain of the right ankle, without any history of trauma. The man was a keen sportsman. Clinical examination revealed a cavoid foot with a good range of movement. No instability was elicited. Marked tenderness was noted in the posterior ankle joint. Pain occurred mainly during the push-off phase of the gait cycle. Radiographs of the ankle Address correspondence and reprint requests to: Dr Rajesh Botchu, 11 Jackson Way, Kettering, NN15 7DL, United Kingdom. Email: drrajeshb@gmail.com

392 R Botchu et al. Journal of Orthopaedic Surgery were normal, but magnetic resonance imaging (MRI) revealed oedema within the PITFL, with associated cysts in the fibular attachment of the ligament (grade II sprain) [Fig. 1]. Physiotherapy and orthotics did not improve the symptoms. The patient underwent ultrasound-guided corticosteroid injection into the PITFL, and the symptoms improved significantly. At the 8-month follow-up, the symptoms had resolved. Patient 2 In June 2010, a 42-year-old woman presented with a 3-month history of posterior ankle pain, without any history of trauma. She had full range of ankle movement, with no signs of ankle instability. Focal tenderness was noted along the inferior syndesmosis. Radiographs were unremarkable, but MRI revealed oedema within the PITFL, with diffuse thickening of the PITFL at its fibular enthesis (grade II sprain) [Fig. 2]. The patient underwent ultrasound-guided corticosteroid injection into the PITFL and achieved a good outcome. At 8-month follow-up, there was no recurrence of posterior ankle pain. Patient 3 In March 2011, a 44-year-old woman presented with a 2-year history of dull ankle pain following an inversion injury. Radiographs were unremarkable, and she was managed symptomatically without success. Her pain was exacerbated on weight bearing, especially when walking on uneven ground. Clinical examination revealed tenderness along the posteromedial ankle joint corresponding to the PITFL. MRI revealed marked oedema within the PITFL (Fig. 3). She underwent ultrasound-guided corticosteroid injection into the PITFL and had complete resolution of her symptoms. At one-year follow-up, there was no recurrence of symptoms. DISCUSSION Ankle ligament sprains are common injuries. 1 5 The (a) (b) (c) (d) Figure 1 Patient 1: (a) radiographs of the ankle showing no abnormality. (b) Sagittal STIR image through the syndesmosis and (c) axial T2-fat-suppressed image showing a thickened oedematous posterior inferior tibiofibular ligament (PITFL) at its fibular insertion (arrows and arrowheads). (d) Axial proton-density image showing an intact deep part of the PITFL (arrowheads). (a) (b) (c) Figure 2 Patient 2: (a) axial STIR, (b) mid sagittal T2-fat-saturated, and (c) coronal images showing diffuse oedema within deep (arrowheads) and superficial (arrows) parts of the posterior inferior tibiofibular ligament.

Vol. 21 No. 3, December 2013 Isolated posterior high ankle sprain 393 daily prevalence in the UK varies from one to 60 per 1000, accounting for a quarter of all musculoskeletal injuries or 10% of the workload in a typical UK accident and emergency department. 1 About 800 mild-to-moderate and 110 severe ankle sprains are treated in the UK a day. 3 85% of these are lateral ankle sprains. 1,6,7 These account for approximately half of all basketball-related injuries and a quarter of all soccer-related injuries. 8,9 Football, ice hockey, and skiing are other sports commonly associated (a) Figure 3 Patient 3: Axial (a) proton-density and (b) STIR images showing diffuse oedema within deep (arrowhead) and superficial (arrow) parts of the posterior inferior tibiofibular ligament. (b) with these injuries. 9,10 The distal tibiofibular joint is involved in almost 10% of ankle sprains. 6,7 These syndesmosis injuries are known as high ankle sprains and are associated with chronic ankle instability, and recurrent and prolonged ankle pain. The incidence is significantly higher in adolescent females, especially athletes, and is lowest in elderly males. 3,11 The fibrous joint between the distal tibia and fibula is the syndesmosis, which is stabilised by the interosseous membrane and ligaments. The ligaments of the distal tibiofibular syndesmosis include the AITFL, PITFL, inferior transverse ligament, and interosseous ligament. 12 The PITFL is a triangular, multifascicular ligament that spans the lateral malleolus to the distal tibial posterior margin of the fibular notch (the Volkmann s tubercle). 12,13 It is the strongest of the syndesmotic ligaments. 6 It runs obliquely (20º of the horizontal plane). 7 It has superficial and deep fibres (Fig. 4). The superficial fibres traverse the posterolateral fibula to the posterior tibial tubercle, working in conjunction with the AITFL to stabilise the syndesmosis. The deep fibres of the PITFL is the traverse tibiofibular ligament. 9,13 The articular labrum of the lateral ridge of the trochlear of the talus is formed by the PITFL, predominantly the deep fibres. This contributes to the posterior stability of the talus. 9,14 The tibial attachment is wider and the fibular attachment is narrower (i.e. compact). The AITFL and deep part of the PITFL contribute a third each towards the stability of the fibula at the distal tibiofibular syndesmosis. The superficial PITFL (a) (b) (c) Figure 4 Coronal proton-density images through the posterior edge of the talo-crural joint showing the (a) deep and (b) superficial parts of the posterior inferior tibiofibular ligament (PITFL) [arrows]. (c) Axial proton-density image through the distal syndesmosis showing the deep (arrowhead) and superficial (arrow) parts of the PITFL.

394 R Botchu et al. Journal of Orthopaedic Surgery contributes only 9% of the stability of the fibula. The mechanism of high ankle sprain involves external rotation and abduction of a dorsiflexed ankle. 15,16 This results in rotation of the talus, followed by external rotation of the fibula and disruption of the syndesmotic ligament, predominantly the AITFL. The AITFL is usually the first syndesmotic ligament to give way. 17 If the ankle is in hyperdorsiflexion during the impact, this causes a wood splitter wedge force to be exerted on the ankle mortice by the broad posterior aspect of the talus, which can result in disruption of both the AITFL and PITFL. Adduction of the hyperdorsiflexed ankle results in isolated PITFL injury. 13 Fibular displacement on loading is minimal following isolated section of the PITFL. 16 Isolated injury of the PITFL is rare; it is usually associated with other injuries. 18 Clinical examination of the mechanism of injury and the presence of point tenderness over the PITFL is the key to the diagnosis of high ankle sprains. 16 Supramalleolar pain should raise suspicion of the diagnosis. Syndesmotic injuries are associated with increased pain, especially during the push-off phase of the gait cycle. 19,20 In contrast to lateral ankle sprains, the amount of soft-tissue oedema is significantly less. 20 Diagnosis based on radiographs is difficult, especially as these are usually partial tears and not associated with diastasis. 13 MRI has good sensitivity and specificity for high ankle sprain. 13,21 Calcification in the syndesmosis can be seen in chronic injuries. Isolated PITFL injury can result in thickening and oedema of the PITFL, with associated bone marrow oedema at its tibial or fibular attachment. 13 These high ankle sprains can be associated with osteochondral injuries, bone marrow oedema, and lateral ankle ligamentous injuries. 22 Isolated PITFL injuries are managed nonsurgically and symptomatically. Treatment involves partial or non-weightbearing, with the aid of orthotics. 23,24 The use of a brace, crutches, analgesics, and corticosteroids have been suggested. 10,23,24 Surgery should be considered if the AITFL is involved. 16 Syndesmotic injuries require a longer period of rehabilitation. 13,25,26 A large proportion of ankle sprains have persistent pain and ankle instability 6 months after injury. 6,7 If undiagnosed, long-term instability can result. 10,13 Appropriate management decreases morbidity and enables a rapid return to usual activities. DISCLOSURE No conflicts of interest were declared by the authors. REFERENCES 1. Nyanzi CS, Langridge J, Heyworth JR, Mani R. Randomized controlled study of ultrasound therapy in the management of acute lateral ligament sprains of the ankle joint. Clin Rehabil 1999;13:16 22. 2. Pijnenburg AC, Van Dijk CN, Bossuyt PM, Marti RK. Treatment of ruptures of the lateral ankle ligaments: a meta-analysis. J Bone Joint Surg Am 2000;82:761 73. 3. Bridgman SA, Clement D, Downing A, Walley G, Phair I, Maffulli N. Population based epidemiology of ankle sprains attending accident and emergency units in the West Midlands of England, and a survey of UK practice for severe ankle sprains. Emerg Med J 2003;20:508 10. 4. Clanton TO, Paul P. Syndesmosis injuries in athletes. Foot Ankle Clin 2002;7:529 49. 5. Williams GN, Jones MH, Amendola A. Syndesmotic ankle sprains in athletes. Am J Sports Med 2007;35:1197 207. 6. Hermans JJ, Beumer A, de Jong TA, Kleinrensink GJ. Anatomy of the distal tibiofibular syndesmosis in adults: a pictorial essay with a multimodality approach. J Anat 2010;217:633 45. 7. Ebraheim NA, Taser F, Shafiq Q, Yeasting RA. Anatomical evaluation and clinical importance of the tibiofibular syndesmosis ligaments. Surg Radiol Anat 2006;28:142 9. 8. http://www.iaaf.org/mm/document/imported/42031.pdf. 9. Norkus SA, Floyd RT. The anatomy and mechanisms of syndesmotic ankle sprains. J Athl Train 2001;36:68 73. 10. Lin CF, Gross ML, Weinhold P. Ankle syndesmosis injuries: anatomy, biomechanics, mechanism of injury, and clinical guidelines for diagnosis and intervention. J Orthop Sports Phys Ther 2006;36:372 84. 11. Waterman BR, Owens BD, Davey S, Zacchilli MA, Belmont PJ Jr. The epidemiology of ankle sprains in the United States. J Bone Joint Surg Am 2010;92:2279 84. 12. Boonthathip M, Chen L, Trudell DJ, Resnick DL. Tibiofibular syndesmotic ligaments: MR arthrography in cadavers with anatomic correlation. Radiology 2010;254:827 36. 13. Evans JM, Schucany WG. Radiological evaluation of a high ankle sprain. Proc (Bayl Univ Med Cent) 2006;19:402 5. 14. Bartonícek J. Anatomy of the tibiofibular syndesmosis and its clinical relevance. Surg Radiol Anat 2003;25:379 86. 15. Teramoto A, Kura H, Uchiyama E, Suzuki D, Yamashita T. Three-dimensional analysis of ankle instability after tibiofibular syndesmosis injuries: a biomechanical experimental study. Am J Sports Med 2008;36:348 52.

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