In general, athletes without frank diastasis or dynamic instability on weight-bearing or stress radiographs can be treated nonsurgically.16 The athlete should be informed that recovery from a syndesmotic injury takes longer than that for an inversion ankle sprain and may require more extensive treatment.10 Nussbaum et al16 found that the time to return to full competitive activity was directly associated with the level of tenderness along the interosseous membrane.
The rehabilitation process is implemented in three phases: acute (I), subacute (II), and integration to sport (III)21 (Table 1). The protocols for each phase of rehabilitation are tailored individually to achieve the goals of joint protection, minimization of inflammatory response, and pain control for the acute phase; restoration of mobility, strength, and gait for the subacute phase; and increased strength, neuromuscular control, and sports-specific tasks for the last phase. Grade III injuries in athletes are relatively uncommon and are typically managed surgically. The principles and methods of fixation are similar to those used for fractures with syndesmotic instability.
Many unstable syndesmotic injuries are associated with fractures; thus, most of the literature focuses on surgical management of fractures with unstable syndesmotic injuries. When these injuries occur, surgical anatomic reduction of the fracture and stabilization of the syndesmosis, if necessary, are typically indicated.
Fibular fractures commonly occur with syndesmotic injury. Open reduction of the fracture to correct length and rotation can result in an anatomic reduction of the syndesmosis.27 High fibular fractures (ie, Maisonneuve fractures) are associated with more extensive interosseous disruption and syndesmotic instability and can often be indirectly reduced. However, open reduction is indicated if shortening or malrotation of the fibula is suspected. Although radiography is helpful for delineating fractures, prediction of a syndesmotic injury based on the fracture pattern and location on preoperative radiographs can be misleading in up to one third of cases.28 Current evidence supports primary repair of an associated injury to the deltoid ligament only in the setting of suspected interposition of capsular tissues or a hematoma that is blocking reduction after anatomic reduction of the fibular fracture.29 In these cases, a medial approach should be considered. When medial malleolar fractures are present, they should be anatomically reduced and fixed with lag screws.
The posterior malleolus contains the tibial PITFL attachment. Biomechanical and clinical evidence suggests that fixation of displaced posterior malleolar fractures can be beneficial for syndesmotic stability and reduction. In a study of 15 patients with pronation-external rotation stage 4 ankle injuries with posterior malleolar fractures, Gardner et al30 found that the PITFL remained intact. The authors also reported a mechanical advantage to posterior malleolar fixation over syndesmotic fixation. A subsequent study by Miller et al31 demonstrated comparable clinical and radiographic outcomes with posterior malleolar fixation, syndesmotic fixation, and combined fixation at a mean follow-up of 15 months. Reduction and fixation of the posterior malleolar fragments are typically indicated when the fragment is displaced and larger than 25% to 33% of the plafond.32 Fixation can be performed using screws or a buttressing plate-and-screw construct.
Syndesmotic stability should always be assessed after fracture fixation regardless of pattern. The hook test and external rotation stress test can both be performed under fluoroscopic evaluation. In the hook test, the fibula is translated laterally, typically by applying a lateral translation force on the foot. Widening of the syndesmosis or medial clear space indicates a positive test. Both of these intraoperative tests have a high specificity but a moderate to low sensitivity.33 Normally, tibiofibular overlap should be maintained, and the tibiofibular clear space should not exceed 6 mm for the hook test. The medial clear space should not exceed 4 mm total for the external rotation stress test (Figure 5). Maintaining the hindfoot in varus while applying an external rotation force has been shown to improve the sensitivity of radiography in detecting a combined injury to the deltoid ligament and syndesmosis.34 When the results are equivocal, ankle arthroscopy can be used to confirm instability and reduction.
Screw fixation remains the most common fixation method for syndesmotic injuries. Despite extensive biomechanical and clinical research, no consensus exists on several aspects of screw fixation, including the screw size, number of screws, number of cortices involved, location of fixation, postoperative care, and the need for implant removal.35 Adequate stabilization of the syndesmosis throughout the healing period can be achieved with 4.5-mm or 3.5-mm screws. However, the larger screws have not been shown to offer a superior biomechanical advantage over the smaller screws.11 Although the 4.5-mm screws are less likely than the 3.5-mm screws to break, greater fixation strength may not be clinically necessary or desirable (Figure 6). Ease of screw removal is one benefit of using 4.5-mm screws, but these screws leave a larger defect in the tibia and fibula, which can be a potential stress riser.
The number of screws used can affect the stability of syndesmotic fixation. In a three-dimensional motion analysis of cadaver specimens, Huber et al36 found that screw fixation resulted in nonphysiologic stabilization of the fibula regardless of the number of screws used or the number of cortices involved. Markolf et al11 found that the number of cortices involved in fixation of the syndesmosis demonstrated no significant effect on the mechanical stability of the distal fibula in a simulated loading test. In a randomized controlled trial of 120 patients with syndesmotic disruption, no difference was reported between three- and four-cortex fixation in terms of loss of reduction, screw breakage, or the need for implant removal.37 However, a trend toward higher loss of reduction was reported in patients with tricortical fixation and in those who did not comply with weight-bearing restrictions.
Screws are generally placed 2 to 5 cm proximal and parallel to the ankle joint to avoid injury to the articular surface. To avoid an injury to the perforating branch of the peroneal artery, screws should be placed 2.3 to 4.1 cm proximal to the joint in women and 2.8 to 5.9 cm proximal to the joint in men.38 Screws should be directed anteriorly along the intermalleolar axis to avoid malreduction.39
Although no consensus exists on the optimal postoperative care after syndesmotic fixation, most surgeons recommend a non–weight-bearing status for a minimum of 4 to 6 weeks to prevent fixation failure.40 In athletes, syndesmotic screws are routinely removed at a minimum of 8 weeks, but screw removal at 12 weeks is ideal.41 However, good evidence is lacking to support routine screw removal in the general population.42 Given the physiologic motion at the syndesmosis, screws may loosen or break when left in place. Recent retrospective series have suggested that patients with loosened or broken screws have outcomes similar to those of patients with intact screws.43 One study reported a complication rate of up to 22.4% associated with screw removal.41 Based on the available data, screw removal should be reserved for patients with intact screws that cause irritation or reduced range of motion for 4 to 6 months.44
Although no consensus exists on guidelines for the treatment of competitive athletes with syndesmotic injuries, our preferred approach is outlined in Figure 8.
Because both clinical and plain radiographic criteria for the diagnosis of an unstable syndesmotic injury may not be reliable,23 close patient follow-up is required to ensure that there is improvement in physical signs and symptoms. Obtaining follow-up full weight-bearing radiographs is also critical.
For stable grade I sprains with injury only to the AITFL and/or anterior deltoid, management involves immediate rest, ice, and immobilization in a non–weight-bearing cast or a removable boot for 3 to 5 days to allow the acute inflammation and swelling to subside. After this period, weight bearing is allowed as tolerated in a boot, and passive- and active-assisted motion is initiated with trainers or physical therapists, followed by resistance and proprioception. Once the athlete is pain free in the boot (typically, 7 to 10 days), he or she transitions to a stabilizing brace, and strengthening and functional exercises begin, followed by running and integration of sport-specific activities. The ability to repeatedly perform a single-leg hop is a reliable sign of healing. Integration of sport-specific activities is permitted when the athlete is able to do a single-leg hop 10 times without significant pain.
Management of grade II injuries varies. Athletes with a competent deltoid and PITFL without diastasis on radiography can typically be treated nonsurgically, with good results. Recovery time is about 2 to 3 times longer than that for a high-grade inversion sprain. For an elite athlete with a grade II injury and clinical or radiographic evidence of dynamic instability or injury to the PITFL and deltoid on MRI, we recommend a live fluoroscopic examination performed with the patient under anesthesia and, if necessary, arthroscopy to assess the syndesmosis and confirm the diagnosis (Figure 3). In our practice, syndesmotic widening >2 mm warrants fixation. This distance can be measured arthroscopically using a length-labeled probe. Alternatively, if a 3.5-mm arthroscopic small joint shaver fits into the syndesmosis, diastasis is confirmed (Figure 4). For grade II injuries in which (1) a more severe injury pattern is suspected based on MRI findings, but instability is not demonstrated on stress radiography, or (2) nonsurgical management has failed, minimally invasive fixation (eg, percutaneous placement of an implant) may be indicated to stabilize subtle syndesmotic instability. Rehabilitation for these cases can be more aggressive because they have inherent stability. Arthroscopy is a useful adjunct to detect and treat other potential sources of pain.
In elite athletes, purely ligamentous grade III injuries in isolation are uncommon. These injuries more commonly occur with fractures or other injuries. The management approach is similar to that for fracture-associated syndesmotic instability. Screws, suture buttons, or a combination of the two can be used to stabilize the syndesmosis. When appropriate, we prefer to use suture button fixation after the other injuries have been addressed (Figure 7). One or two implants may be used based on the degree of instability and the size of the athlete.
The implant is inserted along the intermalleolar axis and parallel to the ankle joint. In elite athletes who require early return to high-impact activity, the use of a combination of buttress plating and a suture button construct may prevent a stress riser at the drill holes. In athletes weighing >250 lbs, greater stresses are placed on the ankle mortise, and syndesmotic instability is managed using two 3.5-mm or 4.5-mm quadricortical screws as part of a neutralization technique performed with the ankle in a neutral position at the time of fixation. Alternatively, a suture button can be used for initial reduction, and a 3.5- or 4.5-mm solid screw can be placed to stabilize the joint. The screw is removed after a minimum of 3 months and can be replaced with another suture button (Figure 9). More data are needed on clinical success rates and return to play characteristics associated with the use of a suture button, particularly in larger athletes.
We typically perform arthroscopy in the setting of syndesmotic stabilization to identify and address any concomitant intra-articular pathology and to confirm anatomic reduction of the syndesmosis.24 Capsular tissue or deltoid fibers can often block the reduction at the medial gutter and can be removed or débrided arthroscopically. A primary open repair of the deltoid can be performed, although it tends to heal well with immobilization and anatomic reduction of the ankle.
Postoperative care begins with immobilization of the ankle in a splint or boot, with no weight bearing permitted for a period of 4 to 6 weeks. Range-of-motion exercises and resistance training should begin a few days after surgery, as tolerated by the patient. Progressive weight bearing in a boot and strengthening exercises can subsequently be introduced under close supervision. Patients can return to competitive sports at 10 to 12 weeks, depending on injury severity. We suggest that syndesmotic screw removal remain optional, but it is indicated if there is evidence of ankle stiffness associated with intact screws or if symptoms secondary to irritation are present. In the setting of planovalgus alignment, which can increase stress on the syndesmosis, the use of a suture button may be considered following screw removal to enhance stability (Figure 9).
Syndesmotic fixation can lead to complications, including the development of heterotopic ossification, implant failure, wound infection, and, most commonly, malreduction of the distal tibia and fibula.57 Heterotopic ossification is a common, but rarely symptomatic, radiographic finding following syndesmotic injuries treated surgically and nonsurgically (Figure 10). Painful synostoses can be successfully treated with excision. Implant failure typically does not have a negative impact on syndesmotic function unless there is a recurrent diastasis of the syndesmosis, which warrants revision surgery. Mendelsohn et al58 found that patients who were obese were 12 times more likely than nonobese patients to suffer a loss of reduction; diabetes mellitus, smoking status, and the type of construct used were not predictive of loss of reduction. Typically, healing occurs adequately in the first 3 to 4 months after surgery. Loose or broken screws observed after this period can be treated or removed if they are symptomatic. Wound infection is a potential complication associated with syndesmotic fixation, but it may also be related to the severity of the injury or the surgery performed to address associated fractures. Perioperative antibiotic prophylaxis should be used as a primary preventive measure.
Evidence-based Medicine: Levels of evidence are described in the table of contents. In this article, references 9, 17, 27, 31, 33, 37, 43, and 46 are level II studies. References 2, 50, 58, and 59 are level III studies. References 1, 7, 8, 10, 16, 18, 19, 23-25, 28, 30, 35, 44, 45, 49, and 52-57 are level IV studies.
References printed in bold type are those published within the past 5 years.
1. Weening B, Bhandari M: Predictors of functional outcome following transsyndesmotic screw fixation of ankle fractures. J Orthop Trauma 2005;19(2):102–108.
2. Gerber JP, Williams GN, Scoville CR, Arciero RA, Taylor DC: Persistent disability associated with ankle sprains: A prospective examination of an athletic population. Foot Ankle Int 1998;19(10):653–660.
3. 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(6):633–645.
4. Xenos JS, Hopkinson WJ, Mulligan ME, Olson EJ, Popovic NA: The tibiofibular syndesmosis
: Evaluation of the ligamentous structures, methods of fixation, and radiographic assessment. J Bone Joint Surg Am 1995;77(6):847–856.
5. Beumer A, Valstar ER, Garling EH, et al.: Effects of ligament sectioning on the kinematics of the distal tibiofibular syndesmosis
: A radiostereometric study of 10 cadaveric specimens based on presumed trauma mechanisms with suggestions for treatment. Acta Orthop 2006;77(3):531–540.
6. Beumer A, Valstar ER, Garling EH, et al.: External rotation
stress imaging in syndesmotic injuries of the ankle: Comparison of lateral radiography and radiostereometry in a cadaveric model. Acta Orthop Scand 2003;74(2):201–205.
7. Hunt KJ, George E, Harris AH, Dragoo JL: Epidemiology of syndesmosis
injuries in intercollegiate football: Incidence and risk factors from National Collegiate Athletic Association injury surveillance system data from 2004-2005 to 2008-2009. Clin J Sport Med 2013;23(4):278–282.
8. Kaplan LD, Jost PW, Honkamp N, Norwig J, West R, Bradley JP: Incidence and variance of foot and ankle injuries
in elite college football players. Am J Orthop (Belle Mead NJ) 2011;40(1):40–44.
9. Waterman BR, Belmont PJ Jr, Cameron KL, Svoboda SJ, Alitz CJ, Owens BD: Risk factors for syndesmotic and medial ankle sprain: Role of sex, sport, and level of competition. Am J Sports Med 2011;39(5):992–998.
10. Wright RW, Barile RJ, Surprenant DA, Matava MJ: Ankle syndesmosis
sprains in national hockey league players. Am J Sports Med 2004;32(8):1941–1945.
11. Markolf KL, Jackson SR, McAllister DR: Syndesmosis
fixation using dual 3.5 mm and 4.5 mm screws with tricortical and quadricortical purchase: A biomechanical study. Foot Ankle Int 2013;34(5):734–739.
12. Haraguchi N, Armiger RS: A new interpretation of the mechanism of ankle fracture. J Bone Joint Surg Am 2009;91(4):821–829.
13. Wei F, Villwock MR, Meyer EG, Powell JW, Haut RC: A biomechanical investigation of ankle injury under excessive external foot rotation in the human cadaver. J Biomech Eng 2010;132(9):091001.
14. Wei F, Post JM, Braman JE, Meyer EG, Powell JW, Haut RC: Eversion during external rotation
of the human cadaver foot produces high ankle sprains. J Orthop Res 2012;30(9):1423–1429.
15. Wei F, Meyer EG, Braman JE, Powell JW, Haut RC: Rotational stiffness of football shoes influences talus motion during external rotation
of the foot. J Biomech Eng 2012;134(4):041002.
16. Nussbaum ED, Hosea TM, Sieler SD, Incremona BR, Kessler DE: Prospective evaluation of syndesmotic ankle sprains without diastasis. Am J Sports Med 2001;29(1):31–35.
17. Uys HD, Rijke AM: Clinical association of acute lateral ankle sprain with syndesmotic involvement: A stress radiography
and magnetic resonance imaging study. Am J Sports Med 2002;30(6):816–822.
18. de César PC, Avila EM, de Abreu MR: Comparison of magnetic resonance imaging to physical examination for syndesmotic injury after lateral ankle sprain. Foot Ankle Int 2011;32(12):1110–1114.
19. Sikka RS, Fetzer GB, Sugarman E, et al.: Correlating MRI findings with disability in syndesmotic sprains of NFL players. Foot Ankle Int 2012;33(5):371–378.
20. Kiter E, Bozkurt M: The crossed-leg test for examination of ankle syndesmosis
injuries. Foot Ankle Int 2005;26(2):187–188.
21. Williams GN, Jones MH, Amendola A: Syndesmotic ankle sprains in athletes. Am J Sports Med 2007;35(7):1197–1207.
22. Sman AD, Hiller CE, Rae K, et al.: Diagnostic accuracy of clinical tests for ankle syndesmosis
injury. Br J Sports Med 2015;49(5):323–329.
23. Sman AD, Hiller CE, Refshauge KM: Diagnostic accuracy of clinical tests for diagnosis of ankle syndesmosis
injury: A systematic review. Br J Sports Med 2013;47(10):620–628.
24. Takao M, Ochi M, Oae K, Naito K, Uchio Y: Diagnosis of a tear of the tibiofibular syndesmosis
: The role of arthroscopy of the ankle. J Bone Joint Surg Br 2003;85(3):324–329.
25. Wolf BR, Amendola AA: Syndesmosis
injuries in the athlete: When and how to operate. Curr Opin Orthop 2002;13(2):151–154.
26. Scranton PE Jr: Sprains and soft tissue injuries, in Pfefer G, ed: Chronic Ankle Pain in the Athlete. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2000, pp 3–20.
27. Pelton K, Thordarson DB, Barnwell J: Open versus closed treatment of the fibula in Maissoneuve injuries. Foot Ankle Int 2010;31(7):604–608.
28. Nielson JH, Sallis JG, Potter HG, Helfet DL, Lorich DG: Correlation of interosseous membrane tears to the level of the fibular fracture. J Orthop Trauma 2004;18(2):68–74.
29. Stufkens SA, van den Bekerom MP, Knupp M, Hintermann B, van Dijk CN: The diagnosis and treatment of deltoid ligament lesions in supination-external rotation
ankle fractures: A review. Strategies Trauma Limb Reconstr 2012;7(2):73–85.
30. Gardner MJ, Brodsky A, Briggs SM, Nielson JH, Lorich DG: Fixation of posterior malleolar fractures provides greater syndesmotic stability. Clin Orthop Relat Res 2006;447(447):165–171.
31. Miller AN, Carroll EA, Parker RJ, Helfet DL, Lorich DG: Posterior malleolar stabilization of syndesmotic injuries is equivalent to screw fixation. Clin Orthop Relat Res 2010;468(4):1129–1135.
32. Carr J: Malleolar fractures and soft tissue injuries of the ankle, in: Browner B, Jupiter J, Levine A, Trafton P, eds. Skeletal Trauma: Basic Science, Management, and Reconstruction, ed 3. Philadelphia, PA, Elsevier Science, 2003, vol 2, p 2307–2374.
33. Pakarinen H, Flinkkilä T, Ohtonen P, et al.: Intraoperative assessment of the stability of the distal tibiofibular joint in supination-external rotation
injuries of the ankle: Sensitivity, specificity, and reliability of two clinical tests. J Bone Joint Surg Am 2011;93(22):2057–2061.
34. Femino JE, Vaseenon T, Phisitkul P, Tochigi Y, Anderson DD, Amendola A: Varus external rotation
stress test for radiographic detection of deep deltoid ligament disruption with and without syndesmotic disruption: A cadaveric study. Foot Ankle Int 2013;34(2):251–260.
35. Schepers T: Acute distal tibiofibular syndesmosis
injury: A systematic review of suture-button versus syndesmotic screw repair. Int Orthop 2012;36(6):1199–1206.
36. 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 Surg 2012;18(3):203–209.
37. Moore JA Jr, Shank JR, Morgan SJ, Smith WR: Syndesmosis
fixation: A comparison of three and four cortices of screw fixation without hardware removal. Foot Ankle Int 2006;27(8):567–572.
38. McKeon KE, Wright RW, Johnson JE, McCormick JJ, Klein SE: Vascular anatomy of the tibiofibular syndesmosis
. J Bone Joint Surg Am 2012;94(10):931–938.
39. Phisitkul P, Ebinger T, Goetz J, Vaseenon T, Marsh JL: Forceps reduction of the syndesmosis
in rotational ankle fractures: A cadaveric study. J Bone Joint Surg Am 2012;94(24):2256–2261.
41. Schepers T, Van Lieshout EM, de Vries MR, Van der Elst M: Complications of syndesmotic screw removal. Foot Ankle Int 2011;32(11):1040–1044.
42. Schepers T, van Zuuren WJ, van den Bekerom MP, Vogels LM, van Lieshout EM: The management of acute distal tibio-fibular syndesmotic injuries: Results of a nationwide survey. Injury 2012;43(10):1718–1723.
43. Hamid N, Loeffler BJ, Braddy W, Kellam JF, Cohen BE, Bosse MJ: Outcome after fixation of ankle fractures with an injury to the syndesmosis
: The effect of the syndesmosis
screw. J Bone Joint Surg Br 2009;91(8):1069–1073.
44. Schepers T: To retain or remove the syndesmotic screw: A review of literature. Arch Orthop Trauma Surg 2011;131(7):879–883.
45. Naqvi GA, Shafqat A, Awan N: Tightrope fixation of ankle syndesmosis
injuries: Clinical outcome, complications and technique modification. Injury 2012;43(6):838–842.
46. Naqvi GA, Cunningham P, Lynch B, Galvin R, Awan N: Fixation of ankle syndesmotic injuries: Comparison of tightrope fixation and syndesmotic screw fixation for accuracy of syndesmotic reduction. Am J Sports Med 2012;40(12):2828–2835.
47. Forsythe K, Freedman KB, Stover MD, Patwardhan AG: Comparison of a novel FiberWire-button construct versus metallic screw fixation in a syndesmotic injury model. Foot Ankle Int 2008;29(1):49–54.
48. Klitzman R, Zhao H, Zhang LQ, Strohmeyer G, Vora A: Suture-button versus screw fixation of the syndesmosis
: A biomechanical analysis. Foot Ankle Int 2010;31(1):69–75.
49. Thornes B, Shannon F, Guiney AM, Hession P, Masterson E: Suture-button syndesmosis
fixation: Accelerated rehabilitation and improved outcomes. Clin Orthop Relat Res 2005;431:207–212.
50. Cottom JM, Hyer CF, Philbin TM, Berlet GC: Transosseous fixation of the distal tibiofibular syndesmosis
: Comparison of an interosseous suture and endobutton to traditional screw fixation in 50 cases. J Foot Ankle Surg 2009;48(6):620–630.
51. Coetzee J, Eberling P: Treatment of syndesmosis
disruptions with TightRope fixation. Tech Foot Ankle Surg 2008;7(3)196–202.
52. Qamar F, Kadakia A, Venkateswaran B: An anatomical way of treating ankle syndesmotic injuries. J Foot Ankle Surg 2011;50(6):762–765.
53. DeGroot H, Al-Omari AA, El Ghazaly SA: Outcomes of suture button
repair of the distal tibiofibular syndesmosis
. Foot Ankle Int 2011;32(3):250–256.
54. Willmott HJ, Singh B, David LA: Outcome and complications of treatment of ankle diastasis with tightrope fixation. Injury 2009;40(11):1204–1206.
55. Sagi HC, Shah AR, Sanders RW: The functional consequence of syndesmotic joint malreduction at a minimum 2-year follow-up. J Orthop Trauma 2012;26(7):439–443.
56. Storey P, Gadd RJ, Blundell C, Davies MB: Complications of suture button
stabilization with modifications of surgical technique. Foot Ankle Int 2012;33(9):717–721.
57. Symeonidis PD, Iselin LD, Chehade M, Stavrou P: Common pitfalls in syndesmotic rupture management: A clinical audit. Foot Ankle Int 2013;34(3):345–350.
58. Mendelsohn ES, Hoshino CM, Harris TG, Zinar DM: The effect of obesity on early failure after operative syndesmosis
injuries. J Orthop Trauma 2013;27(4):201–206.
59. Miller AN, Carroll EA, Parker RJ, Boraiah S, Helfet DL, Lorich DG: Direct visualization for syndesmotic stabilization of ankle fractures. Foot Ankle Int 2009;30(5):419–426.
60. Darwish HH, Glisson RR, DeOrio JK: Compression screw fixation of the syndesmosis
. Foot Ankle Int 2012;33(10):893–899.
61. Michelson JD: Ankle fractures resulting from rotational injuries. J Am Acad Orthop Surg 2003;11(6):403–412.