ABSTRACT
BACKGROUND: Despite the increasing international popularity of CrossFit, there is a paucity of scientific evidence on the risk of CrossFit-related musculoskeletal injuries (CRMIs). PURPOSE: To investigate the incidence (cumulative incidence proportion [IP] and incidence density [ID]) of CRMIs and the association of CRMIs with personal and training characteristics. STUDY DESIGN: Descriptive epidemiology study. METHODS: A prospective, 12-week descriptive epidemiology cohort study was conducted in a convenience sample of CrossFit facilities in a single Brazilian city. Printed baseline questionnaires were distributed to 13 CrossFit boxes. All participants who filled out the questionnaire and consented to participate in the study were invited to respond to an online follow-up questionnaire every 2 weeks to collect data on CrossFit training characteristics and CRMIs. A CRMI was defined as any self-reported musculoskeletal injury or pain that prevented an athlete from exercising for at least 1 day. The IP was defined as the number of new cases divided by the entire population at risk, while the ID was defined as new events divided by the total person-time exposure in hours. Logistic mixed models were developed to investigate the association of CRMIs with personal and training characteristics. RESULTS: A total of 515 CrossFit participants filled out the baseline questionnaire and provided informed consent, and 406 (78.8%) completed at least 1 follow-up measure. There were 133 participants who reported at least 1 CRMI during the study, and a total of 247 unique and new CRMIs were reported over a total estimated person-time exposure to CrossFit of 13,041 hours. The IP was 32.8% (95% CI, 28.4%-37.5%). The ID was 18.9 (95% CI, 16.6-21.3) per 1000 hours of CrossFit exposure. The shoulders (19.0%; n = 47) and lumbar spine (15.0%; n = 37) were most affected. Muscle injuries (45.3%; n = 112) and joint pain (24.7%; n = 61) were the most common CRMI types reported. Switching between prescribed and scaled down training loads (odds ratio [OR], 3.5 [95% CI, 1.7-7.3]) and previous injuries (OR, 3.2 [95% CI, 1.4-7.7]) were risk factors for a CRMI, while CrossFit experience was identified as a protective factor (OR, 0.7 [95% CI, 0.5-1.0]). CONCLUSION: In this 12-week prospective study, the ID was 18.9 CRMIs per 1000 hours of exposure; switching between training loads and previous injuries was associated with 3.5- and 3.2-fold higher odds, respectively, of sustaining CRMIs.
ABSTRACT
BACKGROUND: The middle genicular artery (MGA) is responsible for the blood supply to the cruciate ligaments and synovial tissue. Traumatic sports injuries and surgical procedures (open and arthroscopic) can cause vascular damage. Little attention has been devoted to establish safe parameters for the MGA. PURPOSE: To investigate the anatomy of the MGA and its relation to the posterior structures of the knees, mainly the posterior capsule and femoral condyles, and to establish safe parameters to avoid harming the MGA. STUDY DESIGN: Descriptive laboratory study. METHODS: Dissection of the MGA was performed in 16 fresh, unpaired adult human cadaveric knees with no macroscopic degenerative or traumatic changes and no previous surgeries. The specimens were meticulously evaluated with emphasis on preservation of the MGA. The distances from the MGA to the medial and lateral femoral condyles were measured. The Mann-Whitney test was used for statistical analysis. RESULTS: In all specimens, the MGA emerged from the anterior aspect of the popliteal artery, distal to the superior genicular arteries, and had a short distal trajectory toward the posterior capsule where it entered proximal to the oblique popliteal ligament. The artery lay in the midportion between the condyles. The distance between the posterior aspect of the tibia and the point of entry of the MGA into the posterior joint capsule was 23.8 ± 7.3 mm (range, 14.72-35.68 mm). There was no correlation between an individual's height and the distance of the entrance point of the MGA into the posterior joint capsule to the posterior superior corner of the tibia. CONCLUSION: The middle genicular artery lies in the midportion between the medial and lateral femoral condyles. CLINICAL RELEVANCE: This knowledge is important for the preservation of the blood supply during posterior knee surgical procedures and to settle a secure distance between the posterior aspect of the tibia and the MGA input. This could decrease and prevent iatrogenic vascular injury risk to the MGA.
