Table IV.

Recommendations for points to consider: eligibility criteria

Consideration	Recommendation
1. Definition of acute knee injury	□The extent and characteristics of acute structural joint damage should be fully classified by magnetic resonance imaging □Subgroups/types of injury for inclusion such as ACL and/or meniscal tear should be carefully defined □Different types of injury may be associated with different biomechanical outcomes and responsiveness to any given intervention, so the target population needs to be carefully defined □In the case of meniscal tears, the individual's age, history of a clear injurious episode, plus MR appearances are all important in identifying traumatic tears (and excluding degenerative lesions from these studies) □Caution should be exercised in the inclusion of extreme phenotypes, for example those with isolated ACL tears or very extensive injuries
2. Time since injury	□Establishing an appropriate therapeutic time-window will be relevant for each new target/intervention □Certain interventions targeting the early response to injury may benefit from being tested within days of injury, or up to a maximum of 4–6 weeks from injury
3. Age	□Upper age limit should be carefully considered; an upper age limit of 35 was proposed □Challenges were highlighted around intervening in paediatric populations who lack capacity to give informed consent or who have immature growth plates
4. Demographics	□People of both sexes should be included □Studies may include, but should not be restricted, to professional athletes
5. Proposed exclusions	□ Other existing causes of joint pathology ○ inflammatory arthritis or pre-existing established osteoarthritis ○ other disorders of bone, current or past ○ previous substantial injury or surgery of index knee (particularly where there would be an associated markedly increased risk of PTOA) ○ other concomitant body injury or surgery (in some circumstances as may confound biomarkers) □Pregnancy or breast-feeding □Heavy use of alcohol, or recreational drug use □Morbid obesity