Table 1.

Summary of search 1 terms: studies investigating the association between concussion and risk of musculoskeletal injury

Study	Cohort	Na (M/F)	Post-concussion time frame	Outcome (95% confidence interval)	Interpretation
Makdissi et al. [62]	Professional Australian football	276 (276/0)	1 competitive match	Injury rate ratio 2.23 (0.93–5.04)	Despite a large rate ratio, there were no statistical injury rate group differences. The authors only observed injuries in a single competitive match after concussion
Brooks et al. [54]	Mixed college	257 (194/63)	90 d	OR 2.48 (1.04–5.91)	Concussed athletes had higher odds of experiencing LE injuries than controls within a 90-day window after concussion
Cross et al. [57]	Professional rugby union	810 (810/0)	24 mo	Injury rate ratio 1.6 (1.4–1.9)	Professional rugby union players had a 60% greater risk of experiencing time-loss injuries than players with no concussion
Lynall et al. [56]	Mixed college	102 (67/35)	12 mo	Injury rate ratio Pre- vs. post-concussionb = 1.97 (1.19–3.28) Concussion vs. control = 1.64 (1.07–2.51)	Concussed athletes were 1.97 times more likely to experience an LE injury after concussion than before, and 1.64 times more likely compared with matched controls for up to 1-y post-concussion
Nordstrom et al. [58]	Professional soccer	1665 (1665/0)	12 mo	HRc Post- to pre-concussion = 1.47 (1.05–2.05) Compared with controls: 0–3 mo: 1.56 (1.09–2.23) 3–6 mo: 2.78 (1.58–4.89) 6–12 mo: 4.07 (2.14–7.76)	Professional soccer players were 47% more likely to experience an injury after concussion as compared with before concussion. Concussion increased acute injury risk (HR = 1.70; 1.20–2.41), but not gradual-onset injury risk (HR = 1.00; 0.60–1.66). The risk of injury was about 2.2 times greater in concussed players as compared with controls throughout the total follow-up period
Burman et al. [64]	Mixed athlete	1540 (1091/449)	24 mo	OR Pre-concussiond = 1.98 (1.45–2.72) Post-concussione = 1.72 (1.26–2.37)	Both pre- and post-concussion, concussed players were more likely than controls to experience a subsequent injury
Pietrosimone et al. [63]	Retired professional football	2429 (2429/0)	Reported history	ORf 1 concussion vs. 0 concussions = 1.59 (1.30–1.94) 2 concussions vs. 0 concussions = 2.29 (1.85–2.83) 3+ concussions vs. 0 concussions = 2.86 (2.36–3.48)	Concussion and musculoskeletal injury histories were associated in retired professional football players
Nyberg et al. [65]	Professional ice hockey	264 (264/0)	42 d	χ2 No statistical differences (p ≥ 0.12) Concussion group had more severe injuries (p ≥ 0.04)	Compared with those who had a knee injury, concussed professional hockey players were not at an increased risk for injury, but did have more severe (absence >27 d) injuries within 21 d of return to play
Herman et al. [55]	Mixed college	221 (158/63)	90 d	OR 3.39 (1.90–6.05)	Concussed athletes had higher odds of experiencing LE injuries than controls within a 90-d window after concussion, but overall time loss owing to the subsequent injury was not different between groups
Gilbert et al. [59]	Mixed college	335 (127/208)	Reported history	ORg 1.61–2.87	Concussion and musculoskeletal injury histories were associated in college athletes, with specific associations between concussion and lateral ankle sprain (OR = 1.79), knee injury (OR = 2.13), and LE muscle strain (OR = 1.61)

Unless otherwise noted, all studies compared a concussion group with a control group, and all outcome ratios are reported as concussion/control

F female, HR hazard ratio, LE lower extremity, M male, OR odds ratio

^aN indicates the total sample size (concussion and control groups), broken into total F and M participants

^bCompared injury rates in year post-concussion to year pre-concussion in the concussion group only

^cReported results are when controlling for the number of injuries in the year preceding concussion

^dAnalyzed injuries prior to concussion compared with the control group

^eAnalyzed injuries after concussion compared with the control group

^fReported OR for those who had a history of 1, 2, or 3+ concussions compared with those with 0 concussions

^gReported multiple ORs for different LE injuries