The negative impact of anterior cruciate ligament reconstruction in professional male footballers.

BACKGROUND: Soccer is one of the most common international sports in which ACL injuries occur, with previous studies reporting high return-to-play rates following ACL reconstruction (ACLR). Return-to-play analysis fails to take into consideration how effective a player remains once returning to competition. The aims of this study are to provide a large-scale international analysis of return-to-play and player performance statistics among professional soccer athletes following ACLR. METHODS: Using publicly available sources, professional soccer athletes who have undergone ACLR between the 1996 and 2015 seasons were identified. Player metrics including statistical performance, recovery time, and return-to-play rates were analyzed both before and after reconstruction. Furthermore, player performance statistics during each of three consecutive seasons post-ACLR were compared. RESULTS: A total of 176 athletes who underwent ACLR were included in this study. The return-to-play rate was 93.2% (164 athletes). Cumulative post-surgical statistical analysis of ACLR players demonstrated fewer games/season, minutes/season, minutes/game, goals/season, and more fouls/season following ACLR (p < 0.04). Analysis of player performance statistics suggests that athletes do not return to their baseline number of games/season and minutes/game until two and three seasons post-ACLR, respectively. At three seasons post-ACLR, athletes are still starting fewer games/season and scoring fewer goals/90 min (p < 0.04). CONCLUSION: Return-to-play rate is high following ACLR; however, athletes exhibit poorer statistical performance, especially in the first few seasons upon return. Our data shows that athletes continue to start fewer games/season and score fewer goals/90 min at three seasons post-ACLR.

Bone formation after damaging in vivo fatigue loading results in recovery of whole-bone monotonic strength and increased fatigue life.

Bone has a remarkable capacity for self-repair. We previously reported a woven bone response after damaging in vivo fatigue loading of the rat ulna that led to a rapid recovery of whole-bone strength. In the current study we asked: does the bone response in the 12 days after damaging fatigue loading result in a bone that has normal fatigue properties? The right forelimbs of 52 adult rats were subjected to a single bout of in vivo fatigue loading. Nonloaded left forelimbs were used as controls. Ulnar geometric properties were assessed by peripheral quantitative computed tomography (pQCT) and ex vivo mechanical properties were assessed by three-point bending. On day 0, ulnae from loaded forelimbs had a 15-20% reduction in stiffness and ultimate force versus controls (p < 0.10), indicative of structural damage. On day 12, bone area at the midshaft was increased by 27% (p < 0.001) and microCT scans revealed periosteal woven bone at this site. This bone response led to a recovery of the monotonic properties of loaded ulnae at day 12 versus control (stiffness, p = 0.73; ultimate force, p = 0.96). Importantly, fatigue testing ex vivo at day 12 demonstrated significantly greater fatigue life in in vivo loaded ulnae versus controls (p < 0.001). Additionally, the slope of the fatigue-life curve was significantly less in loaded versus control ulnae (p < 0.002). We conclude that woven bone "repair" of a bone damaged by fatigue loading restores whole-bone strength and enhances resistance to further damage by repetitive loading.