Injury History and Perceived Knee Function as Risk Factors for Knee Injury in Youth Team-Sports Athletes.

BACKGROUND: The identification of risk factors for sports injuries is essential before injury prevention strategies can be planned. HYPOTHESIS: Previous acute knee injury and lower perceived knee function measured by Knee injury and Osteoarthritis Outcome Score (KOOS) will increase the risk of acute knee injury in youth team-sports athletes. STUDY DESIGN: Prospective cohort study. LEVEL OF EVIDENCE: Level 3. METHODS: At baseline, youth (≤21 years old) male and female basketball and floorball athletes completed a questionnaire on previous acute knee injuries and perceived knee function (KOOS). A total of 211 male and 183 female athletes were followed for an acute knee injury up to 3 years. Unadjusted and adjusted Cox regression models were used in risk factor analyses. RESULTS: In male athletes, previous acute knee injury and lower KOOS Pain, Activities of Daily Living, Sport and Recreation, and knee-related Quality of Life subscale scores increased the risk of acute knee injury in the unadjusted analyses. Adjusted analyses for male injuries were not performed because of low number of acute knee injuries (n = 18). In female athletes, previous acute knee injury increased the risk of acute knee injury when adjusted for athletes' age and body mass index (hazard ratio, 2.6 [95% CI, 1.3-5.2]). In female athletes, none of the KOOS subscale scores were associated with the increased risk of acute knee injury in the adjusted analyses. CONCLUSION: Previous acute knee injury was associated with the risk of new acute knee injury in youth male and female athletes. In youth male athletes, additionally, lower perceived knee function in 4 out of 5 KOOS subscale scores were associated with the increased risk of new acute knee injury. CLINICAL RELEVANCE: The treatment and rehabilitation of the present acute knee injury and secondary prevention of reinjury should be emphasized in youth team-sports athletes.

R-Ras regulates vascular permeability, but not overall healing in skin wounds.

Wounds close by keratinocytes migrating from the edge of the wound and re-epithelializing the epidermis. It has been proposed that the major stimuli for wound closure are blood-derived growth factors, chemokines and cytokines. The small GTPase R-Ras, a known integrin activator, also regulates vascular permeability during angiogenesis, and blood vessels lacking R-Ras leak plasma proteins constantly. We explored whether the access to blood-derived proteins influences skin wound healing in R-Ras knockout (KO) mice. In skin wounds, R-Ras expression was mostly restricted to the vasculature in the granulation tissue. Angiogenic blood vessels in the R-Ras KO mice were significantly more permeable than in wild-type (WT) controls. Although the distances between epidermal tongues, and the panniculus carnosus muscles, were significantly longer in R-Ras KO than WT controls before the granulation tissue formation took place, there were no differences in the wound closure or re-epithelialization rates or granulation tissue formation. These findings were also corroborated in a special splint excision wound model. Our study shows that although R-Ras does not influence the skin wound healing itself, the blood vessels lacking R-Ras are leaky and thus could facilitate the access of blood-derived proteins to the wound.

Acute injuries in Finnish junior floorball league players.

OBJECTIVES: To investigate the incidence and characteristics of acute time-loss injuries in Finnish junior floorball league players. DESIGN: Prospective cohort study with 3-year follow-up. METHODS: One hundred and eighty-six female and male players (mean age 16.6±1.4) took part in the follow-up study (2011-2014). The training hours and games were recorded on a team diary. Floorball related acute injuries were registered and verified by a research physician. The injury incidence was expressed as the number of injuries per 1000h of exposure. Incidence rate was calculated separately for games and practices, and for males and females. RESULTS: One hundred and forty-four acute time-loss injuries occurred. Injury incidence was 26.87 (95% CI 20.10-33.63) in junior league games, and 1.25 (95% CI 0.99-1.52) in team practices. Female players had significantly higher game injury rate (IRR 1.88, 1.12-3.19) and joint/ligament injury rate (IRR 1.70, 1.07-2.73) compared to males. Eighty-one percent of the injuries affected the lower limbs. The ankle (37%), knee (18%), and thigh (14%) were the most commonly injured body sites. More than half of injuries involved joint or ligaments (54%). Twenty-six percent of the injuries were severe causing more than 28days absence from sports. Eight anterior cruciate ligament ruptures of the knee occurred among seven female players. CONCLUSION: The study revealed that risk of ankle and knee ligament injuries is high in adolescent floorball, specifically among female players.