Outcomes of Activity-Related Lower Extremity Muscle Tears After Application of the British Athletics Muscle Injury Classification: A Systematic Review.

Context: Muscle injury classification and grading systems have been reported for >100 years; yet it offer limited evidence relating the clinical or radiological qualities of a muscle injury to the pathology or clinical outcome. The British Athletics Muscle Injury Classification (BAMIC) incorporates recent predictive features of muscle injuries and provides a precise radiographic framework for clinical prediction and management.

Objective: To investigate clinical outcomes, particularly time to return to play (RTP), reinjury rate (RIR), and prognostic value of specific magnetic resonance imaging (MRI) findings, of activity-related muscle injuries (tears) in athletes after application of the BAMIC.

Data sources: A search of PubMed (NLM), EMBASE (Ovid), Web of Science (Clarivate), Cochrane Library (Wiley), and ClinicalTrials.gov from the inception date of each database through August 31, 2022, was conducted. Keywords included the BAMIC.

Study selection: All English language studies evaluating clinical outcomes of RTP and RIR after activity-related muscle injuries and where BAMIC was applied were included. A total of 136 articles were identified, and 11 studies met inclusion criteria.

Study design: Systematic review (PROSPERO: CRD42022353801).

Level of evidence: Level 2.

Data extraction: Two reviewers independently screened studies for eligibility and extracted data. Methodological quality of included study was assessed independently by 2 reviewers with the Newcastle-Ottawa Quality Scale (NOS); 11 good quality studies (4 prospective cohort studies, 7 retrospective cohort studies) with 468 athletes (57 female) and 574 muscle injuries were included.

Results: All studies reported a statistically significant relationship between BAMIC grade, BAMIC injury site, and/or combined BAMIC grade and injury site with RTP. A statistically significant increased RIR was reported by BAMIC grade and BAMIC injury site in 2 of 4 and 3 of 4 studies, respectively. The prognostic value of individual MRI criteria was limited.

Conclusion: Consistent evidence suggests that BAMIC offers prognostic and therapeutic guidance for clinical outcomes, particularly RTP and RIR, after activity-related muscle injuries in athletes that may be superior to previous muscle injury classification and grading systems.