Stable Versus Unstable Grade II High Ankle Sprains: A Prospective Study Predicting the Need for Surgical Stabilization and Time to Return to Sports

Arthroscopy. 2016 Apr;32(4):634-42. doi: 10.1016/j.arthro.2015.10.003. Epub 2015 Dec 22.


Purpose: To investigate grade II syndesmosis injuries in athletes and identify factors important in differentiating stable from dynamically unstable ankle sprains and those associated with a longer time to return to sports.

Methods: Sixty-four athletes with an isolated syndesmosis injury (without fracture) were prospectively assessed, with a mean follow-up period of 37 months (range, 24 to 66 months). Those with an associated deltoid ligament injury or osteochondral lesion were included. Those whose injuries were considered stable (grade IIa) were treated conservatively with a boot and rehabilitation. Those whose injuries were clinically unstable underwent arthroscopy, and if instability was confirmed (grade IIb), the syndesmosis was stabilized. Clinical and magnetic resonance imaging assessments of injury to individual ligaments were recorded, along with time to return to play. A power analysis estimated that each group would need 28 patients.

Results: All athletes returned to the same level of professional sport. The 28 patients with grade IIa injuries returned at a mean of 45 days (range, 23 to 63 days) compared with 64 days (range, 27 to 104 days) for those with grade IIb injuries (P < .0001). There was a highly significant relationship between clinical and magnetic resonance imaging assessments of ligament injury (anterior tibiofibular ligament [ATFL], anterior-inferior tibiofibular ligament [AITFL], and deltoid ligament, P < .0001). Instability was 9.5 times as likely with a positive squeeze test and 11 times as likely with a deltoid injury. Combined injury to the anterior-inferior tibiofibular ligament and deltoid ligament was associated with a delay in return to sports. Concomitant injury to the ATFL indicated a different mechanism of injury-the syndesmosis is less likely to be unstable and is associated with an earlier return to sports.

Conclusions: A positive squeeze test and injury to the ATFL and deltoid ligament are important factors in differentiating stable from dynamically unstable grade II injuries and may be used to identify which athletes may benefit from early arthroscopic assessment and stabilization. They may also be important in predicting the time frame for athletes' expected return to play.

Level of evidence: Level II, prospective comparative study.

MeSH terms

  • Ankle Injuries / physiopathology
  • Ankle Injuries / rehabilitation
  • Ankle Injuries / surgery*
  • Ankle Joint / physiopathology*
  • Ankle Joint / surgery
  • Arthroscopy / methods*
  • Athletic Injuries / physiopathology
  • Athletic Injuries / rehabilitation
  • Athletic Injuries / surgery*
  • Follow-Up Studies
  • Fractures, Bone / complications
  • Humans
  • Ligaments, Articular / injuries
  • Ligaments, Articular / surgery*
  • Magnetic Resonance Imaging
  • Prospective Studies
  • Return to Sport / physiology*
  • Sprains and Strains / physiopathology
  • Sprains and Strains / rehabilitation
  • Sprains and Strains / surgery*
  • Time Factors
  • Treatment Outcome