More than 670,000 total knee replacements are performed annually in the United States; however, high-quality evidence to support the effectiveness of the procedure, as compared with nonsurgical interventions, is lacking.

Background No systematic review has identified the incidence of running-related injuries per 1000 h of running in different types of runners. Objective The purpose of the present review was to systematically search the literature for the incidence of running-related injuries per 1000 h of running in different types of runners, and to include the data in meta-analyses. Data Sources A search of the PubMed, Scopus, SPORTDiscus, PEDro and Web of Science databases was conducted. Study Selection Titles, abstracts, and full-text articles were screened by two blinded reviewers to identify prospective cohort studies and randomized controlled trials reporting the incidence of running-related injuries in novice runners, recreational runners, ultra-marathon runners, and track and field athletes. Study Appraisal and Synthesis Methods Data were extracted from all studies and comprised for further analysis. An adapted scale was applied to assess the risk of bias. Results After screening 815 abstracts, 13 original articles were included in the main analysis. Running-related injuries per 1000 h of running ranged from a minimum of 2.5 in a study of long-distance track and field athletes to a maximum of 33.0 in a study of novice runners. The meta-analyses revealed a weighted injury incidence of 17.8 (95 % confidence interval [CI] 16.7–19.1) in novice runners and 7.7 (95 % CI 6.9–8.7) in recreational runners. Limitations Heterogeneity in definitions of injury, definition of type of runner, and outcome measures in the included full-text articles challenged comparison across studies. Conclusion Novice runners seem to face a significantly greater risk of injury per 1000 h of running than recreational runners.

Although epidemiologic studies of tibial plateau fractures have been conducted, none have included geographically defined populations or a validated fracture classification based on computed tomography (CT). The goals of this study were to provide up-to-date information on the incidence and basic epidemiology of tibial plateau fractures in a large unselected patient population and to report the mechanisms of injury involved and the distribution of fractures according to a validated CT-based fracture classification. The authors conducted a population-based epidemiologic study of all patients treated for tibial plateau fracture over a 6-year period from 2005 to 2010. The study was based on an average background population of 576,364 citizens. A retrospective review of hospital records was performed. During this time, a total of 355 patients were treated for tibial plateau fracture. This group included 166 men and 189 women, and mean age was 52.6 years (SD, 18.3). The most common fracture type was AO type 41-B3, representing 35% of all tibial plateau fractures. The second most common fracture type was AO type 41-C3, representing 17% of all tibial plateau fractures. The incidence of tibial plateau fractures was 10.3 per 100,000 annually. Compared with women, men younger than 50 years had a higher incidence of fractures. The incidence of fractures increased markedly in women older than 50 years but decreased in men older than 50 years. In both sexes, the highest frequency was between the ages of 40 and 60 years. [ Orthopedics. 2015; 38(9):e780–e786.]

Background: The prevalence of adolescent knee pain is 33%, and patellofemoral pain (PFP) is the most common diagnosis with a nontraumatic onset. The 2-year prognosis of adolescent PFP compared with other types of knee pain is unknown. Purpose: To investigate the 2-year prognosis of knee pain among adolescents with and without a diagnosis of PFP. Study Design: Cohort study; Level of evidence, 2. Methods: In 2011, a cohort of 2200 adolescents aged 15 to 19 years answered an online questionnaire on musculoskeletal pain. Of these, 504 reported knee pain, and 153 of these were clinically diagnosed with PFP. After 2 years, the 504 adolescents, as well as 252 randomly selected adolescents who did not report knee pain in 2011, were contacted again. Primary outcome at follow-up was the proportion of adolescents with knee pain during the last week prior to follow-up. Results: Overall, 55.9% (95% CI, 50.8%-60.9%) of those reporting knee pain at baseline also reported pain 2 years later. Adolescents diagnosed with PFP had a 1.26 (95% CI, 1.05-1.50) higher relative risk (RR) of knee pain at follow-up compared with other types of knee pain. Adolescents with PFP were significantly more likely to reduce or stop sports participation compared with adolescents with other types of knee pain. Of those without knee pain at baseline, 12.8% (95% CI, 8.4%-17.2%) reported knee pain at follow-up in 2013. Adolescents with knee pain at baseline had a 4.51 (95% CI, 3.15-6.45) higher RR of knee pain at follow-up compared with adolescents without knee pain at baseline. Conclusion: Knee pain during adolescence, and PFP in particular, is in most cases present after 2 years and thus may not be self-limiting. A greater focus on early detection and prevention of knee pain during adolescence is needed.