ObjectiveTo estimate knee osteoarthritis (OA) risk following anterior cruciate ligament (ACL), meniscus or combined ACL and meniscus injury.DesignSystematic review and meta-analysis.Data sourcesMEDLINE, Embase, SPORTDiscus, CINAHL and Web of Science until November 2018.Eligibility criteria for selecting studiesProspective or retrospective studies with at least 2-year follow-up including adults with ACL injury, meniscal injury or combined injuries. Knee OA was defined by radiographs or clinical diagnosis and compared with the contralateral knee or non-injured controls.Study appraisal and synthesisRisk of bias was assessed using the SIGN50 checklist. ORs for developing knee OA were estimated using random effects meta-analysis.Results53 studies totalling ∼1 million participants were included: 185 219 participants with ACL injury, mean age 28 years, 35% females, 98% surgically reconstructed; 83 267 participants with meniscal injury, mean age 38 years, 36% females, 22% confirmed meniscectomy and 73% unknown; 725 362 participants with combined injury, mean age 31 years, 26% females, 80% treated surgically. The OR of developing knee OA were 4.2 (95% CI 2.2 to 8.0; I2=92%), 6.3 (95% CI 3.8 to 10.5; I2=95%) and 6.4 (95% CI 4.9 to 8.3; I2=62%) for patients with ACL injury, meniscal injury and combined injuries, respectively.ConclusionThe odds of developing knee OA following ACL injury are approximately four times higher compared with a non-injured knee. A meniscal injury and a combined injury affecting both the ACL and meniscus are associated with six times higher odds compared with a non-injured knee. Large inconsistency (eg, study design, follow-up period and comparator) and few high-quality studies suggest that future studies may change these estimates.Clinical relevancePatients sustaining a major knee injury have a substantially increased risk of developing knee OA, highlighting the importance of knee injury prevention programmes and secondary prevention strategies to prevent or delay knee OA development.PROSPERO registration number CRD42015016900

Objectives To investigate the benefits and harms of exercise therapy on physical and psychosocial health in people with multimorbidity. Design Systematic review of randomised controlled trials (RCTs). Data sources MEDLINE, EMBASE, CENTRAL and CINAHL from 1990 to April 20th, 2020 and Cochrane reviews on the effect of exercise therapy for each of the aforementioned conditions, reference lists of the included studies, the WHO registry and citation tracking on included studies in Web of Science. Eligibility criteria for study selection RCTs investigating the benefit of exercise therapy in people with multi-morbidity, defined as two or more of the following conditions: osteoarthritis (of the knee or hip), hypertension, type 2 diabetes, depression, heart failure, ischemic heart disease, and chronic obstructive pulmonary disease on at least one of the following outcomes: Health-related quality of life (HRQoL), physical function, depression or anxiety. Summary and quality of the evidence Meta-analyses using a random-effects model to assess the benefit of exercise therapy and the risk of non-serious and serious adverse events according to the Food and Drug Administration definition. Meta-regression analyses to investigate the impact of pre-specified mediators of effect estimates. Cochrane ‘Risk of Bias Tool’ 2.0 and the GRADE assessment to evaluate the overall quality of evidence. Results Twenty-three RCTs with 3363 people, testing an exercise therapy intervention (mean duration 13.0 weeks, SD 4.0) showed that exercise therapy improved HRQoL (standardised mean difference (SMD) 0.37, 95 % CI 0.14 to 0.61) and objectively measured physical function (SMD 0.33, 95 % CI 0.17 to 0.49), and reduced depression symptoms (SMD -0.80, 95 % CI -1.21 to -0.40) and anxiety symptoms (SMD -0.49, 95 % CI -0.99 to 0.01). Exercise therapy was not associated with an increased risk of non-serious adverse events (risk ratio 0.96, 95 % CI 0.53-1.76). By contrast, exercise therapy was associated with a reduced risk of serious adverse events (risk ratio 0.62, 95 % CI 0.49 to 0.78). Meta-regression showed that increasing age was associated with lower effect sizes for HRQoL and greater baseline depression severity was associated with greater reduction of depression symptoms. The overall quality of evidence for all the outcomes was downgraded to low, mainly due to risk of bias, inconsistency and indirectness. Conclusions Exercise therapy appears to be safe and to have a beneficial effect on physical and psychosocial health in people with multimorbidity. Although the evidence supporting this was of low quality, it highlights the potential of exercise therapy in the management and care of this population.

Knee joint loading exercise seems to not be harmful for articular cartilage in people at increased risk of, or with, knee OA. However, the quality of evidence was low, including some interventions studying activities considered outside the therapeutic loading spectrum to promote cartilage health.