Background Injury to the ipsilateral graft used for reconstruction of the anterior cruciate ligament (ACL) or a new injury to the contralateral ACL are disastrous outcomes after successful ACL reconstruction (ACLR), rehabilitation, and return to activity. Studies reporting ACL reinjury rates in younger active populations are emerging in the literature, but these data have not yet been comprehensively synthesized. Purpose To provide a current review of the literature to evaluate age and activity level as the primary risk factors in reinjury after ACLR. Study Design Systematic review and meta-analysis. Methods A systematic review of the literature was conducted via searches in PubMed (1966 to July 2015) and EBSCO host (CINAHL, Medline, SPORTDiscus [1987 to July 2015]). After the search and consultation with experts and rating of study quality, 19 articles met inclusion for review and aggregation. Population demographic data and total reinjury (ipsilateral and contralateral) rate data were recorded from each individual study and combined using random-effects meta-analyses. Separate meta-analyses were conducted for the total population data as well as the following subsets: young age, return to sport, and young age + return to sport. Results Overall, the total second ACL reinjury rate was 15%, with an ipsilateral reinjury rate of 7% and contralateral injury rate of 8%. The secondary ACL injury rate (ipsilateral + contralateral) for patients younger than 25 years was 21%. The secondary ACL injury rate for athletes who return to a sport was also 20%. Combining these risk factors, athletes younger than 25 years who return to sport have a secondary ACL injury rate of 23%. Conclusion This systematic review and meta-analysis demonstrates that younger age and a return to high level of activity are salient factors associated with secondary ACL injury. These combined data indicate that nearly 1 in 4 young athletic patients who sustain an ACL injury and return to high-risk sport will go on to sustain another ACL injury at some point in their career, and they will likely sustain it early in the return-to-play period. The high rate of secondary injury in young athletes who return to sport after ACLR equates to a 30 to 40 times greater risk of an ACL injury compared with uninjured adolescents. These data indicate that activity modification, improved rehabilitation and return-to-play guidelines, and the use of integrative neuromuscular training may help athletes more safely reintegrate into sport and reduce second injury in this at-risk population.

Background A patellar dislocation is a common knee injury in the young, athletic patient population. Recent trends indicate that the use of long-term nonoperative treatment is decreasing, and surgical intervention is more commonly recommended for those patients who fail initial nonoperative management with recurrent patellar dislocations. Medial patellofemoral ligament (MPFL) reconstruction has become increasingly utilized in this regard. Purpose To evaluate outcomes, particularly return to sports and its relationship to postoperative instability, of isolated MPFL reconstruction for the treatment of recurrent patellar dislocations. Study Design Systematic review and meta-analysis. Methods A review of the current literature was performed using the terms “medial patellofemoral ligament reconstruction” and “MPFL reconstruction” in the electronic search engines PubMed and EBSCOhost (CINAHL, MEDLINE, SPORTDiscus) on July 29, 2015, yielding 1113 abstracts for review. At the conclusion of the search, 14 articles met the inclusion criteria and were included in this review of the literature. Means were calculated for population size, age, follow-up time, and postoperative Tegner scores. Pooled estimates were calculated for postoperative Kujala scores, return to play, total risk of postoperative instability, risk of positive apprehension sign, and risk of reoperation. Results The mean patient age associated with MPFL reconstruction was 24.4 years, with a mean postoperative Tegner score of 5.7. The pooled estimated mean postoperative Kujala score was 85.8 (95% CI, 81.6–90.0), with 84.1% (95% CI, 71.1%–97.1%) of patients returning to sports after surgery. The pooled total risk of recurrent instability after surgery was 1.2% (95% CI, 0.3%–2.1%), with a positive apprehension sign risk of 3.6% (95% CI, 0%–7.2%) and a reoperation risk of 3.1% (95% CI, 1.1%–5.0%). Conclusion A high percentage of young patients return to sports after isolated MPFL reconstruction for chronic patellar instability, with short-term results demonstrating a low incidence of recurrent instability, postoperative apprehension, and reoperations.

Adding mesopore networks in microporous materials using the principles of hierarchical structure design is recognized as a promising route for eliminating their transport limitations and, therefore, for improving their value in technological applications. Depending on the routes of physico-chemical procedures or post-synthesis treatments used, very different geometries of the intentionally-added transport mesopores can be obtained. Understanding the structure-dynamics relationships in these complex materials with multiple porosities under different thermodynamical conditions remains a challenging task. In this review, we summarize the results obtained so far on experimental and theoretical studies of diffusion in micro-mesoporous materials. By considering four common classes of bi-porous materials, which are differing by the inter-connectivities of their sup-spaces as one of the most important parameter determining the transport rates, we discuss their generic transport properties and correlate the results delivered by the equilibrium and non-equilibrium techniques of diffusion measurements.

Objective To evaluate sex differences in incidence rates (IRs) of anterior cruciate ligament (ACL) injury by sport type (collision, contact, limited contact, and noncontact). Data Sources A systematic review was performed using the electronic databases PubMed (1969–January 20, 2017) and EBSCOhost (CINAHL, SPORTDiscus; 1969–January 20, 2017) and the search terms anterior cruciate ligament AND injury AND (incidence OR prevalence OR epidemiology). Study Selection Studies were included if they provided the number of ACL injuries and the number of athlete-exposures (AEs) by sex or enough information to allow the number of ACL injuries by sex to be calculated. Studies were excluded if they were analyses of previously reported data or were not written in English. Data Extraction Data on sport classification, number of ACL injuries by sex, person-time in AEs for each sex, year of publication, sport, sport type, and level of play were extracted for analysis. Data Synthesis We conducted IR and IR ratio (IRR) meta-analyses, weighted for study size and calculated. Female and male athletes had similar ACL injury IRs for the following sport types: collision (2.10/10 000 versus 1.12/10 000 AEs, IRR = 1.14, P = .63), limited contact (0.71/10 000 versus 0.29/10 000 AEs, IRR = 1.21, P = .77), and noncontact (0.36/10 000 versus 0.21/10 000 AEs, IRR = 1.49, P = .22) sports. For contact sports, female athletes had a greater risk of injury than male athletes did (1.88/10 000 versus 0.87/10 000 AEs, IRR = 3.00, P < .001). Gymnastics and obstacle-course races were outliers with respect to IR, so we created a sport category of fixed-object, high-impact rotational landing (HIRL). For this sport type, female athletes had a greater risk of ACL injury than male athletes did (4.80/10 000 versus 1.75/10 000 AEs, IRR = 5.51, P < .001), and the overall IRs of ACL injury were greater than all IRs in all other sport categories. Conclusions Fixed-object HIRL sports had the highest IRs of ACL injury for both sexes. Female athletes were at greater risk of ACL injury than male athletes in contact and fixed-object HIRL sports.