Abstract
Chronic distal tibiofibular syndesmosis disruption can be managed by endoscopic arthrodesis of the syndesmosis. This is performed through the proximal anterolateral and posterolateral portals. The scar tissue and bone block are resected to facilitate the subsequent reduction of the syndesmosis. The reduction of the syndesmosis can be guided either arthroscopically or endoscopically. The tibial and fibular surfaces of the tibiofibular overlap can be microfractured to facilitate subsequent fusion.
The distal tibiofibular syndesmosis is a fibrous joint between the distal tibia and fibula that is stabilized by the distal anterior tibiofibular ligament, the distal posterior tibiofibular ligament, the transverse ligament, and the interosseous ligament.1 Chronic syndesmosis disruption can result from missed diagnosis in the acute injury or after failed or inadequate nonoperative or operative management. It can result in chronic ankle pain and progressive degeneration of the ankle.2, 3, 4 Arthrodesis of the distal tibiofibular syndesmosis is one of the surgical options possible for stabilization of the syndesmosis. We offer a technical guide to endoscopic distal tibiofibular syndesmosis arthrodesis.5
Technique
Step 1: Patient Positioning and Preoperative Setup
The patient is placed in a floppy lateral position. The ankle can be put in a supine position for ankle arthroscopy and a lateral position for the syndesmosis endoscopy. A thigh tourniquet is applied to provide a bloodless operative field. The fluid input is by gravity and no arthro-pump is used. Arthroscopes measuring 2.7 mm 30° and 4.0 mm 30° are used for this procedure. The 2.7 mm 30° arthroscope is used for the ankle arthroscopy, whereas the 4.0 mm 30° arthroscope is preferred for the syndesmosis endoscopy to provide a wider arthroscopic view.
Step 2: Ankle Arthroscopy
First of all, ankle arthroscopy is performed with the standard anterolateral and anteromedial portals. The goal is examination of the ankle joint, and any concomitant lesion (e.g., osteochondral lesion) is dealt with accordingly. With the anterolateral portal as the viewing portal, a fibrous tissue or meniscoid lesion may be found in the medial gutter in case of lateral shift of the talus. The lesion is resected to facilitate the reduction of the talus. The viewing portal is switched to the anteromedial portal. The scar tissue covering the syndesmosis is debrided before the congruity of the syndesmosis can be assessed. Most of the time, the syndesmosis cannot be mobilized adequately to achieve anatomical reduction by arthroscopic debridement alone as only the anterior talofibular ligament and anterior part of the syndesmosis can be adequately debrided. The scarred distal posterior tibiofibular ligament, the transverse ligament, the interosseous ligament, and the bony outgrowth blocking the reduction of the syndesmosis cannot be effectively debrided through the arthroscopic approach as a result of the difficulty associated with inserting the arthroscopic instrument into the posterior aspect of the syndesmosis. This insertion is challenging due to obstruction by the curved outline of the syndesmosis and scarring of its surrounding soft tissues.
Step 3: Extra-articular Syndesmosis Endoscopy
The extra-articular syndesmosis endoscopy is then performed through the proximal anterolateral and proximal posterolateral portals. The goal of the endoscopy is complete debridement of scarred tissue, removal of any bone block, and preparation of the fusion surfaces. The articular edges of the syndesmosis are exposed and the distal fibula is adequately mobilized to allow the anatomical reduction of the syndesmosis. The upper border of the tibiofibular overlap is located fluoroscopically. The proximal anterolateral portal is located 1.5 cm above the upper border of the overlap and lateral to the tibialis anterior tendon. The proximal posterolateral portal is at the lateral border of the Achilles tendon 2 cm above the proximal anterolateral portal (Fig 1). It can be established with the inside-out technique by introducing the trocar through the proximal anterolateral portal and between the distal tibia and fibula above the distal tibiofibular overlap. The proximal anterolateral and proximal posterolateral portals can be switched as the visualization and instrumentation portals, respectively, via the switching rod technique (Fig 2). The scar tissue, including the interosseous distal tibiofibular ligament, can be debrided with an arthroscopic shaver and small periosteal elevator and curette. The bone block is resected with an arthroscopic acromionizer. The depth of the syndesmosis reached by the arthroscopic instrument needs regular verification with fluoroscopy. The surgeon should avoid going into the ankle joint without notice to avoid iatrogenic damage to the articular cartilage. It is possible that a 2.7-mm arthroscope and smaller sized instruments are needed for debridement deep inside the syndesmosis and close to the ankle joint to minimize bone resection. The debridement should go down to the ankle joint. Once debridement is finished, the anterolateral talar dome should be seen through the proximal posterolateral portal. The deep fibrous tissue separating the posterolateral talar dome from the posterior part of the syndesmosis should be preserved to prevent the subsequent bone graft from dropping into the ankle joint. The debridement of the anterior part of the syndesmosis can be difficult as freedom of motion of the instrument through the proximal anterolateral portal can be limited by the shin. The anterolateral ankle portal can be used together with the proximal posterolateral portal to complete the debridement of the anterior part of the syndesmosis (Fig 3). Microfracture of the adjacent tibial and fibular cortices of the syndesmosis is then performed with arthroscopic awls (Table 1, Video 1, Fig 4).
Fig 1.
Left ankle. (A) The proximal anterolateral portal (PALP) is located 1.5 cm above the upper border of the overlap and lateral to the tibialis anterior tendon. (B) The proximal posterolateral portal (PPLP) is at the lateral border of the Achilles tendon 2 cm above the PALP.
Fig 2.
Left ankle. Switching rod technique. (A) The trocar-cannula is introduced from the proximal anterolateral portal to the proximal posterolateral portal. The trocar is removed and the switching rod is inserted into the cannula. (B) The cannula is then removed and reinserted along the rod through the proximal posterolateral portal. The rod is removed and the arthroscopic shaver is inserted half-way into the cannula through the proximal anterolateral portal. (C) The cannula is withdrawn half-way and the arthroscope is inserted. (D) This can guarantee the correct placement of the arthroscope and the shaver.
Fig 3.
Left ankle. (A) The debridement of the anterior rim of the syndesmosis through the proximal anterolateral portal is difficult because the manipulation of the shaver is blocked by the shin of the patient. (B) The shaver can be inserted to the top of the anterior rim of the syndesmosis through the anterolateral ankle portal. The debridement of the anterior rim of the syndesmosis can be started from the top downward. The handpiece of the shaver is moving upward and would not be hindered by the foot or the shin of the patient.
Table 1.
Pearls and Pitfalls of the Endoscopic Distal Tibiofibular Syndesmosis Arthrodesis
| Pearls | Pitfalls |
|---|---|
| 1. Preoperative computed tomography scan is important for preoperative planning. | 1. It cannot correct the syndesmosis malalignment if there is malunion of the fibula. |
| 2. The working space is at the tibiofibular overlap and outside the ankle joint. | 2. The location of the ankle joint cannot be determined endoscopically. |
| 3. Adequate resection of the scar tissue and bone block is essential for the anatomical reduction of the syndesmosis. | 3. The location of the instrument should be checked regularly under fluoroscopy to avoid iatrogenic damage to the ankle joint. |
Fig 4.
Left ankle. Syndesmosis endoscopic views. The proximal posterolateral portal is the viewing portal. (A) Curettage of the scar tissue of the syndesmosis. (B) Resection of the bone block by an arthroscopic acromionizer. (C) Exposure of the anterolateral part of the talar dome (td) after release of the syndesmosis. (D) Preparation of the fusion surfaces by microfracture with an arthroscopic awl. (f, fibula; ib, impinging bone of the distal tibia; t, tibia.)
Step 4: Reduction and Fixation of the Syndesmosis
Ankle arthroscopy is then performed again and guides the anatomic reduction of the syndesmosis. In case of marked arthrofibrosis of the joint, the ankle joint cannot be distracted adequately to allow visualization of the posterior part of the syndesmosis. The reduction of the syndesmosis is then accomplished via endoscopic assessment. The anterior corners of the distal tibia and fibula at the joint level should touch each other and the anterior cortex of the lateral malleolus should be in a smooth line with that of the distal tibia without stepping. This can correct any coronal, sagittal, and rotational disruption of the syndesmosis if present. To have adequate endoscopic view to guide the reduction, more bone should be resected down to the articular edges. The syndesmosis is then stabilized with screws (Fig 5). Any residual space of the syndesmosis if present can be grafted with cancellous graft by means of a bone trephine (Aesculap) through the proximal portals. Postoperatively, a short leg cast is applied and the patient is advised to walk strictly in non–weight-bearing conditions for 8 weeks. The cast is removed 8 weeks after the operation and the patient can start partial weight-bearing walking with a rocker boot for another 4 weeks. The patient can resume full weight-bearing walking in conventional shoes 12 weeks after the operation, and radiographs usually show union of the arthrodesis site at that time.
Fig 5.
(A) Preoperative anteroposterior radiograph of the left ankle of the illustrated case showing lateral displacement of the talus inside the ankle mortise. (B) Postoperative radiograph showing that the syndesmosis is stabilized with 2 screws and the talus is reduced.
Discussion
Chronic distal tibiofibular syndesmosis disruption can result in significant functional deficit and development of posttraumatic ankle arthritis. It is usually a result of missed or inadequately treated acute injury to the syndesmosis and share the same degree of complexity as in acute injuries.6 The disruption pattern can be a combination of coronal, sagittal, rotational, and longitudinal planes.6 Standard radiographic measurements are of limited value in analyzing the disruption pattern.6, 7 Preoperative CT scan should be performed to evaluate the position of the fibula in the incisura tibialis.8 Because of the variation of the normal anatomy of the syndesmosis, it is better to take imaging of the contralateral side for comparison.8
The ankle pain in chronic distal tibiofibular syndesmosis disruption can be due to hypertrophy and impingement of the soft tissue in the distal tibiofibular joint. Arthroscopic debridement alone can be indicated if the chronic distal tibiofibular syndesmosis disruption is not combined with medial ankle instability and lateral displacement of the talus.9 Otherwise, the anatomic reduction and stabilization of the syndesmosis is indicated. The syndesmosis can be stabilized by syndesmotic screw fixation alone, ligamentous reconstruction, or fusion of the syndesmosis.2, 10, 11, 12, 13, 14, 15, 16, 17, 18 Compared with other procedures, arthrodesis of the syndesmosis provides the greatest and long-lasting stability of the syndesmosis. However, it is unclear whether obliteration of motion of the syndesmosis will deteriorate ankle joint function in the future as there is no report that shows the clinical and functional results of arthrodesis of the syndesmosis after long-term follow-up.18 The endoscopic arthrodesis is technically more difficult than the open procedure. Moreover, it cannot correct malunion of the fibula that is indicated for the open procedure. However, it has less surgical trauma and provides adequate visualization and debridement of the syndesmosis to ensure fusion in anatomical position. Endoscopic distal tibiofibular syndesmosis arthrodesis is indicated in chronic disruption of the syndesmosis with lateral displacement of the talus. It is contraindicated in case of disruption of the syndesmosis because of malunion of the fibula.19 Ankle arthroscopy is included into this procedure and has 3 roles: management of associated intra-articular pathologies, resection of the scar tissue, or meniscoid lesion of the medial ankle gutter to facilitate the reduction of the talus and guidance of the reduction of the syndesmosis.6, 7, 13 However, syndesmosis arthrodesis is difficult to be achieved by arthroscopy alone. The soft tissue and bony blockage of the reduction of the syndesmosis are present in extra-articular sites and are difficult to be reached arthroscopically. An endoscopic approach can access the whole area of distal tibiofibular overlap and remove all the soft tissue and bone blocks for the reduction of the syndesmosis. To minimize the amount of bone resection, the scar tissue around the syndesmosis should be adequately released to allow further diastasis of the syndesmosis and debridement of the deep site of the syndesmosis. The articular surfaces of the tibial plafond and lateral malleolus can be preserved as the debridement goes from the tibiofibular overlap toward the ankle joint.
The structures at risk during this endoscopic procedure include the sural nerve, flexor hallucis longus muscle, and the peroneal artery, and its perforating and posterior branches.20 Unlike the arthroscopic instrument used in ankle arthroscopy, the endoscope does not have distinct landmarks to identify the depth of the instrument within the syndesmosis. There is a risk of damage to the articular cartilage of the talar dome if the instruments enter the joint without being noticed. The location of the arthroscopic instrument should be checked frequently with fluoroscopy to avoid iatrogenic damage to the ankle joint. Other potential risks of the procedure include iatrogenic fracture of the distal fibula around the screw head and nonunion of the arthrodesis site. This is a technically demanding procedure and should be reserved for experienced foot and ankle arthroscopists.
Conclusions
Endoscopic arthrodesis of the distal tibiofibular syndesmosis is a viable option to treat chronic disruption of the syndesmosis with lateral displacement of the talus.
Footnotes
The author reports that he has no conflicts of interest in the authorship and publication of this article.
Supplementary Data
Endoscopic distal tibiofibular syndesmosis arthrodesis of the left ankle. The proximal posterolateral portal is the viewing portal. Step 1: The scar tissue of the syndesmosis is resected. Step 2: The distal fibula is assessed for any bony outgrowth blocking reduction of the syndesmosis. The bony outgrowth is resected with an arthroscopic acromionizer. Step 3: The ankle joint is reached and the anterolateral talar dome can be identified. The distal fibula should be adequately mobilized for the subsequent reduction of the syndesmosis. Step 4: The tibial and fibular surfaces of the tibiofibular overlap is microfractured with an arthroscopic awl.
References
- 1.Hermans J.J., Beumer A., de Jong T.A.W., Kleinrensink G.J. Anatomy of the distal tibiofibular syndesmosis in adults: A pictorial essay with a multimodality approach. J Anat. 2010;217:633–645. doi: 10.1111/j.1469-7580.2010.01302.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Lui T.H. Tri-ligamentous reconstruction of the distal tibiofibular syndesmosis: A minimally invasive approach. J Foot Ankle Surg. 2010;49:495–500. doi: 10.1053/j.jfas.2010.06.002. [DOI] [PubMed] [Google Scholar]
- 3.Reckling F.W., McNamara G.R., Desmet A.A. Problems in the diagnosis and treatment of ankle injuries. J Trauma. 1981;21:943–950. doi: 10.1097/00005373-198111000-00006. [DOI] [PubMed] [Google Scholar]
- 4.Sagi H.C., Shah A.R., Sanders R.W. The functional consequence of syndesmotic joint malreduction at a minimum 2-year follow-up. Orthop Trauma. 2012;26:439–443. doi: 10.1097/BOT.0b013e31822a526a. [DOI] [PubMed] [Google Scholar]
- 5.Lui T.H. Arthroscopic arthrodesis of the distal tibiofibular syndesmosis. J Foot Ankle Surg. 2015;54:953–957. doi: 10.1053/j.jfas.2015.02.017. [DOI] [PubMed] [Google Scholar]
- 6.Lui T.H., Ip K.Y., Chow H.T. Comparison of radiologic and arthroscopic diagnoses of distal tibiofibular syndesmosis disruption in acute ankle fracture. Arthroscopy. 2005;21:137e1–137e7. doi: 10.1016/j.arthro.2005.08.016. [DOI] [PubMed] [Google Scholar]
- 7.van den Bekerom M.P.J. Diagnosing syndesmotic instability in ankle fractures. World J Orthop. 2011;2:51–56. doi: 10.5312/wjo.v2.i7.51. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Dikos G.D., Heisler J., Choplin R.H., Weber T.G. Normal tibiofibular relationships at the syndesmosis on axial CT imaging. J Orthop Trauma. 2012;26:433–438. doi: 10.1097/BOT.0b013e3182535f30. [DOI] [PubMed] [Google Scholar]
- 9.Han S.H., Lee J.W., Kim S., Suh J.S., Choi Y.R. Chronic tibiofibular syndesmosis injury: The diagnostic efficiency of magnetic resonance imaging and comparative analysis of operative treatment. Foot Ankle Int. 2007;28:336–342. doi: 10.3113/FAI.2007.0336. [DOI] [PubMed] [Google Scholar]
- 10.Harper M.C. Delayed reduction and stabilization of the tibiofibular syndesmosis. Foot Ankle Int. 2001;22:15–18. doi: 10.1177/107110070102200103. [DOI] [PubMed] [Google Scholar]
- 11.Morris M.W., Rice P., Schneider T.E. Distal tibiofibular syndesmosis reconstruction using a free hamstring autograft. Foot Ankle Int. 2009;30:506–511. doi: 10.3113/FAI.2009.0506. [DOI] [PubMed] [Google Scholar]
- 12.Valkering K.P., Vergroesen D.A., Nolte P.A. Isolated syndesmosis ankle injury. Orthopedics. 2012;5:e1705–e1710. doi: 10.3928/01477447-20121120-13. [DOI] [PubMed] [Google Scholar]
- 13.Wagener M.L., Beumer A., Swierstra B.A. Chronic instability of the anterior tibiofibular syndesmosis of the ankle. Arthroscopic findings and results of anatomical reconstruction. BMC Musculoskelet Disord. 2011;12:212. doi: 10.1186/1471-2474-12-212. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Yasui Y., Takao M., Miyamoto W., Innami K., Matsushita T. Anatomical reconstruction of the anterior inferior tibiofibular ligament for chronic disruption of the distal tibiofibular syndesmosis. Knee Surg Sports Traumatol Arthrosc. 2011;19:691–695. doi: 10.1007/s00167-010-1311-1. [DOI] [PubMed] [Google Scholar]
- 15.Olson K.M., Dairyko G.H., Jr., Toolan B.C. Salvage of chronic instability of the syndesmosis with distal tibiofibular arthrodesis functional and radiographic results. J Bone Joint Surg Am. 2011;93:66–72. doi: 10.2106/JBJS.J.00030. [DOI] [PubMed] [Google Scholar]
- 16.Lambers K.T.A., van den Bekerom M.P.J., Doornberg J.N., Stufkens S.A.S., van Dijk C.N., Kloen P. Long-term outcome of pronation-external rotation ankle fractures treated with syndesmotic screws only. J Bone Joint Surg Am. 2013;95:e122. doi: 10.2106/JBJS.L.00426. [DOI] [PubMed] [Google Scholar]
- 17.Parlamas G., Hannon C.P., Murawski C.D. Treatment of chronic syndesmotic injury: A systematic review and meta-analysis. Knee Surg Sports Traumatol Arthrosc. 2013;21:1931–1939. doi: 10.1007/s00167-013-2515-y. [DOI] [PubMed] [Google Scholar]
- 18.Miyamoto W., Takao M. Management of chronic disruption of the distal tibiofibular syndesmosis. World J Orthop. 2011;18:1–6. doi: 10.5312/wjo.v2.i1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Lui T.H., Chan K.B., Ngai W.K. Premature closure of distal fibular growth plate: A case of longitudinal syndesmosis instability. Arch Orthop Trauma Surg. 2008;128:45–48. doi: 10.1007/s00402-007-0305-z. [DOI] [PubMed] [Google Scholar]
- 20.McKeon K.E., Wright R.W., Johnson J.E., McCormick J.J., Klein S.E. Vascular anatomy of the tibiofibular syndesmosis. J Bone Joint Surg Am. 2012;94:931–938. doi: 10.2106/JBJS.K.00604. [DOI] [PubMed] [Google Scholar]
Associated Data
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Supplementary Materials
Endoscopic distal tibiofibular syndesmosis arthrodesis of the left ankle. The proximal posterolateral portal is the viewing portal. Step 1: The scar tissue of the syndesmosis is resected. Step 2: The distal fibula is assessed for any bony outgrowth blocking reduction of the syndesmosis. The bony outgrowth is resected with an arthroscopic acromionizer. Step 3: The ankle joint is reached and the anterolateral talar dome can be identified. The distal fibula should be adequately mobilized for the subsequent reduction of the syndesmosis. Step 4: The tibial and fibular surfaces of the tibiofibular overlap is microfractured with an arthroscopic awl.