Incidence of Acromioclavicular (AC) Joint Sprains in Hockey

By Tyler Meyers PT, DPT

             AC joint background

  The acromioclavicular (AC) joint is comprised of lateral clavicle and the acromion process of the scapula. This joint conjoins the scapula to the clavicle and serves as the main point of articulation that suspends the upper extremity from the trunk. The primary function of the AC joint is to allow for additional scapular range of motion on the thorax, allow for additional adjustments of the scapula to adhere to the changing shape of the thorax with motion, and transmit forces from the upper extremity to the clavicle. The joint is comprised of three ligaments that are commonly implicated with AC joint injuries. The coracoclavicular ligaments, conoid and trapezoid, and the acromioclavicular ligament serve as the primary reinforcement for the AC joint.1

AC joint and Hockey

The sport of hockey has a large presence in the United States with 547,429 registered athletes according to USA Hockey.2 With the increasing number of participants in the sport it is important to understand the most common forms of injury. Through direct and indirect forces, AC-joint sprains account for about 7.3% of injuries seen at the NCAA collegiate level. The most common source of these injuries is direct forces seen in player-player and player-boards impacts. Even though the sport of football involves more player-player collisions, hockey still saw a greater rate of AC-joint sprains. It is hypothesized that hockey shoulder pads have greater flexibility than football shoulder pads which may play a role in the difference of AC-joint sprain rates between sports.3

AC-joint sprain and Return-to-sport

          With an AC-joint sprain there are varying severities graded with the Rockwood Grading Scale. On this scale the injury ranges from grade I to VI with the severity progressing from least to most. This grading scale helps to assist in the decision-making for proper treatment options to avoid further complications of the injury.

The level of severity of the injury does impact the type of treatment and time to return-to-sport. A study looking at AC-joint sprain severity and return-to-sport showed that all grades of sprain were able to have a successful return-to-sport. The average time amount of time to return-to-sport was 21.7 days with grade I and II injuries returning in 20.1 days compared to 28.3 days for grade III sprains. All the grade I through III injuries were treated nonoperatively with pain control, immediate support with shoulder sling, early mobilization, progressive resistance exercises, and strength/physical reconditioning. Grades IV through VI sprains will typically result in surgical treatment to address the displacement and instability.4

References

1) Dutton M. Orthopaedic: Examination, evaluation, and intervention. The McGraw-Hill Companies Inc. 2008. 2nd ed.

2) USA Hockey. Membership Statistics. https://www.usahockey.com/membershipstats. Published in 2022. Accessed on April 23, 2022.

3) Boltz AJ, Nedimyer AK, Chandran A, et al. Epidemiology of Injuries in National Collegiate Athletic Association Men’s Ice Hockey: 2014-2015 through 2018-2019. J Athl Train. 2021;56(7):703-710

4) White LW, Ehmann J, Bleakney RR, et al. Acromioclavicular joint injuries in professional ice hockey players – epidemiologic and MRI findings and association with return to play. Orthop J Sports Med. 2020;8(11):1-9