Current Concepts Review Injuries to the Ankle Syndesmosis

Current Concepts Review

Injuries to the Ankle Syndesmosis

Tyler J. Van Heest, BA, and Paul M. Lafferty, MD

J Bone Joint Surg Am. 2014;96:603-13 d http://dx.doi.org/10.2106/JBJS.M.00094

Copyright 2014 By The Journal of Bone and Joint Surgery, Incorporated

Investigation performed at the University of Minnesota-Regions Hospital, St. Paul, Minnesota

JACO Editorial Reviewer: Jeffrey R. Cates, DC, MS

Published:
Journal of the Academy of Chiropractic Orthopedists
December 2016, Volume 13, Issue 2

The original article copyright belongs to the original publisher. This review is available from:http://www.dcorthoacademy.com © 2016 Cates and the Academy of Chiropractic Orthopedists. This is an Open Access article which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Author’s Abstract

  • Despite being common, syndesmotic injuries are challenging to diagnose and treat.
  • Anatomic reduction of the ankle syndesmosis is critical for good clinical outcomes.
  • Intraoperative three-dimensional radiography and direct syndesmotic visualization can improve rates of anatomic reduction.
  • The so-called gold-standard syndesmotic screw fixation is being brought increasingly into question as new fixation techniques emerge.
  • Syndesmotic screw removal remains controversial, but may allow spontaneous correction of malreductions.

JACO Editorial Summary:

  • This article is an interesting and well written narrative review. The purpose was to review the diagnosis and management of injuries to the ankle syndesmosis. These types of injuries are seen in 5-10% of ankle sprains and 23% of ankle fractures. The article notes that there is notable disagreement in the medical world on how to best diagnosis and manage these injuries. Treatment can range from conservative to surgical and can include manual reduction, reduction forceps, lag screws, and Kirschner wire fixation.
  • An informative review of the anatomy is provided by the authors. They note the syndesmosis maintains the boundaries of the ankle mortise, while allowing rotation, translation, and migration of the fibula. Complex movements of the fibula occur with various foot positions. The syndesmosis complex includes four ligaments, the interosseous ligament, the anterior inferior tibiofibular ligament, the posterior inferior tibiofibular ligament, and the inferior transverse ligament. The joint receives blood largely by the anterior branch of the peroneal artery which can be damaged with ankle injuries.
  • The most common mechanism of injury to this joint is external rotation and hyperdorsiflextion. These injuries are commonly seen with sport mishaps, slips and falls.
  • Isolated syndesmotic injuries are commonly referred to as high ankle sprains. When diagnosing these, it is important to obtain a detailed history including the present and past injuries and the mechanism of injuries. Stress tests can assist in establishing the diagnosis. The authors review several such tests including;
    • The external rotation stress test which requires stabilization of the leg with the knee in 90 degrees of flexion while an external rotation load is applied at the foot.
    • The squeeze test is done by compressing the proximal part of the fibula to the tibia resulting in separation.
    • A crossed-leg test requires crossing the injured leg over the uninjured one while seated, then the application of gentle downward pressure to the knee of the injured leg.
    • The forced dorsiflexion test forces the ankle into dorsiflexion, then again while compressing the distal tibia and fibula together. Compression can be done manually or with sport tape. Decreasing pain during compression indicates syndesmotic injury.
  • In instances of fracture, syndesmotic stability can be assessed with two common tests during reparative surgery. The hook test is performed by the surgeon using a bone hook to pull the lateral malleolus lateral. Confirmation of movement under fluoroscopy of more than 2 mm is considered positive. The external rotation test is also done under fluoroscopy and involves rotating the foot externally while assessing for an increased medial clear space. The authors report that while both test have excellent interobserver agreement, the sensitivity was poor.
  • Conservative treatment options were reported to be most appropriate for isolated syndesmotic injuries and a three phased treatment plan was presented.
    • Phase I – Protection, rest, ice, compression, elevation, along with pain control, limited weight bearing and light ankle motion exercises.
    • Phase II – Strength and proprioceptive exercises with progression from low intensity – high repetition, to high intensity with low repetition exercises.
    • Phase III – Rigorous strength exercise with focus on sport specific needs. Phase III is generally only needed for athletes.
  • Ankle fractures with syndesmotic injury have routinely been repaired surgically, however one study found no significant difference between those with syndesmotic fixation and those that had no syndesmotic fixation. Clamps used for reduction prior to screw stabilization can cause rotational misalignment. Standard radiographs and fluoroscopy can not reliably detect such malposition making them a common complication of operative fixation.
  • Fixation methods include single or double screws, suture button fixation, or posterior malleolar fixation. There are pros and cons to each technique.
  • Conservative treatment outcomes tend to show that syndesmotic sprains have longer healing periods than lateral ankle sprains. In the operative area, the suture button is initially more expensive than the syndesmotic screw fixation; however, screws often need to be removed once healing is accomplished. Besides malreduction other surgical complications include screw breakage, which reportedly occurs in 7% to 29% of screw fixation cases. To avoid this complication, fixation screws are often removed at 6 to 12 weeks. Obese and neuropathic patients have a higher risk of complications. Heterotopic ossification occurs in a large number of patients, especially if fixation was accomplished with bioabsorbable screws.
  • The authors conclude that the available data leaves many questions left unanswered, however, it does question the concept of syndesmotic screw fixation as a gold-standard treatment method. The authors provide recommendations with graded evidence:
  • Radiographic evaluation is effective in diagnosing moderate to severe syndesmotic injuries, but often fails to detect subtle ones.
  • It is important to intraoperatively stress all surgically treated ankle fractures to evaluate latent syndesmotic injury.
  • Patients with distal tibiofibular diastasis and persistent symptoms despite conservative management can benefit from delayed operative treatment.
  • Posterior malleolar fixation can restore syndesmotic stability.
  • Anatomic reduction of the syndesmosis may not be reliably determined with intraoperative fluoroscopy or standard radiographs.
  • Anatomic reduction of the syndesmosis is essential for improving functional outcomes and avoiding posttraumatic osteoarthritis.
  • Several strategies, such as intraoperative three-dimensional imaging, postoperative computed tomography, and imaging of the contralateral syndesmosis, improve rates of anatomical reduction.
  • Syndesmotic screw removal may provide immediate improvement to outcome scores, yet screw removal is not without risks.
  • Use of 3 to 4 quadricortical syndesmotic screws should be considered for patients who are at a higher risk of fixation failure.
  • Most isolated syndesmotic injuries can be treated conservatively.

B

C

C

C

C

C

C

C

I

I

Grade A indicates good evidence. Grade B, fair evidence. Grade C, conflicting or poor-quality evidence.
Grade I, insufficient evidence to make a recommendation

Summary:

This review covered a topic that has not received a lot of attention or high level research. The knowledge provided can assist the chiropractic physician in diagnosing and managing syndesmotic injuries. While this work is very informative, the reader should note that this is not a systematic review, nor should the recommendations be confused with those of properly constructed guidelines. As such, the information and recommendations should be considered in that light and, if possible, compared to higher level quality research sources.