Epidemiology of MRI-detected muscle injury in athletes participating in the Tokyo 2020 Olympic Games

Hiroki Katagiri; Bruce B Forster; Lars Engebretsen; Jae-Sung An; Takuya Adachi; Yukihisa Saida; Kentaro Onishi; Hideyuki Koga

doi:10.1136/bjsports-2022-105827

Epidemiology of MRI-detected muscle injury in athletes participating in the Tokyo 2020 Olympic Games

Br J Sports Med. 2022 Dec 5;57(4):218-224. doi: 10.1136/bjsports-2022-105827. Online ahead of print.

Authors

Hiroki Katagiri^{1

2}, Bruce B Forster³, Lars Engebretsen⁴, Jae-Sung An¹, Takuya Adachi⁵, Yukihisa Saida⁵, Kentaro Onishi^{6

7}, Hideyuki Koga⁸

Affiliations

¹ Department of Joint Surgery and Sports Medicine, Tokyo Medical and Dental University Graduate School of Medical and Dental Sciences, Bunkyo-ku, Tokyo, Japan.
² Department of Orthopaedic Surgery, Dokkyo Medical University Saitama Medical Center, Koshigaya, Saitama, Japan.
³ Department of Radiology, The University of British Columbia Faculty of Medicine, Vancouver, British Columbia, Canada.
⁴ Orthopedic Clinic, Oslo University Hospital and Oslo Sports Trauma Research Center, Norwegian School of Sports Sciences, Oslo, Norway.
⁵ Department of Diagnostic Radiology, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan.
⁶ Department of Physical Medicine and Rehabilitation, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
⁷ Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
⁸ Department of Joint Surgery and Sports Medicine, Tokyo Medical and Dental University Graduate School of Medical and Dental Sciences, Bunkyo-ku, Tokyo, Japan koga.orj@tmd.ac.jp.

Abstract

Objective: Muscle injury is one of the most common injuries occurring at the Olympic Games often with devastating consequences. Epidemiological injury surveillance is recognised by the IOC as essential for injury prevention and management. We aimed to describe the incidence, anatomical location and classification of MRI-detected muscle injuries in athletes who participated in the Tokyo 2020 Olympic Games.

Methods: Two board-certified orthopaedic surgeons, highly experienced in reviewing MRIs, independently and retrospectively reviewed all MRIs collected at the Tokyo 2020 Olympic Games from clinical reports generated by board-certified musculoskeletal radiologists at the IOC Polyclinic. The presence and anatomical site of muscle injuries were classified as: type a: myofascial/peripheral; type b: muscle belly or musculotendinous junction; and type c: injury which extends into the tendon, with reference to the British Athletics Muscle Injury Classification.

Results: Fifty-nine MRI-detected muscle injuries were seen in 40 male and 19 female athletes. 24 athletes (41%) were unable to fully compete in their event. Fifty-two injuries (88%) involved lower extremity muscles with hamstring muscle injuries most common (32 of 59, 54%). Half of all muscle injuries occurred in athletes participating in athletics (30 of 59, 51%). 21 athletes (35%) sustained type a injuries, 14 athletes (24%) type b injuries and 24 athletes (41%) type c injuries. Of athletes with type c injuries, 18 (75%) did not complete their competition, a rate significantly higher than types a and b (OR 14.50, 95% CI 4.0 to 51.9, p<0.001).

Conclusion: For athletes sustaining muscle injuries during the Olympic Games, our study demonstrates the prognostic relevance of muscle injury anatomical site and severity for predicting completion or non-completion of an Olympic athlete's competition.

Keywords: Magnetic Resonance Imaging; epidemiology; muscle.