Introduction
Artificial turf (AT) playing surfaces have emerged as a common alternative to natural grass (NG) at all levels of athletic competition from youth to professional. While several prior articles have compared the lower extremity injury rates on AT and NG, the heterogeneity of these studies in terms of design and methodology has led to widely variable results. The purpose of this systematic review was to determine whether any definitive conclusions can be drawn with regard to the risk of lower extremity injury on AT and NG playing surfaces.
Methods
A systematic review of the English-language literature was performed according to the PRISMA guidelines. All included studies presented a direct comparison of injury rates on AT versus NG playing surfaces. No restrictions were made with regard to sport, level of competition, level of evidence, or year of publication. Studies that examined only head injury rates (e.g. concussions) without any comparison of overall injury rates or lower extremity injury rates were excluded. Systematic reviews and meta-analyses were also excluded. The following data elements were extracted from each article: publication year, study design, level of evidence, industry funding, cohort selection process (ad-hoc vs. systematic), sport, level of competition, number of athletic seasons, injury setting, AT type, overall injury rate, knee rate, and foot & ankle injury rate. AT types were classified into Old Generation (1st or 2nd generation) or New Generation (3rd generation or higher).
Results
53 articles ranging in publication year from 1972 to 2020 met inclusion criteria. 31 articles compared overall injury rates (indiscriminate of anatomic location) on AT versus NG. Roughly one-half of these studies (51.6%) found no significant difference between NG and AT, while one-third (35.5%) found a higher overall injury rate on AT and just 4 studies (12.9%) found a higher overall injury rate on NG. Similarly, of the 26 articles comparing knee injury rates, 14 studies (53.8%) reported no significant difference between AT and NG, 8 studies (30.8%) reported a higher injury rate on AT, and 4 studies (15.4%) reported a higher injury rate on NG. With regard to foot & ankle injuries, however, a majority of articles (14/24, 58.3%) reported a higher injury rate on AT. Comparatively few articles (3/24, 12.5%) reported a higher foot & ankle injury rate on NG, while the remaining articles (7/24, 29.2%) reported no difference in foot & ankle injury rate between AT and NG. Moreover, this trend toward a higher foot & ankle injury rate on AT persisted when New Generation and Old Generation playing surfaces were analyzed separately. Further analysis of the 3 articles reporting a higher foot & ankle injury rate on NG also revealed that 2 of these studies (66.7%) utilized ad-hoc cohort selection and received industry funding from an AT manufacturing company.
Conclusions
The present study is a systematic review of 53 articles in the English-language literature that compared injury rates on AT and NG. Our findings suggest that the rates of overall injury and knee injury are similar between these two playing surfaces, though AT may be associated with a higher rate of foot & ankle injuries compared to NG.