Soft-tissue Quadriceps Autograft ACL-reconstruction in the Skeletally-immature vs. Hamstrings

ACL graft failure is a composite outcome defined by MRI confirmation of rupture and/or asymmetrical symptomatic laxity (i.e., positive Lachman and/or positive pivot shift).

Return to sport (at any level and to pre-injury level) will be evaluated using the Tegner Activity Scale. The Tegner activity level scale is a graduated list of activities of daily living, recreation, and competitive sports, in which the response is presented as an 11-point Likert scale, where 0 indicates the lowest level of ability to perform work and sport functions, and 10 indicates competitive participation in high level sports.

Patient Knee Function will be evaluated using the Pediatric International Knee Documentation Committee Subjective Form (Pedi-IKDC). The Pedi-IKDC is a 15 question form that consists of measures of daily living and sport activity, in which the response options are presented as either 4 or 10 point Likert scales. Scores for the form range from 0 (lowest level of function) to 100 (highest level of function).

Knee pain will be evaluated using a 100-point Visual Analogue Scale (VAS). The VAS has been validated in ACL patients and is one of the most commonly used pain rating scores both in research and clinical practice as it is an easy-to-use, validated, one-dimensional scale that does not require verbal or reading skills.

Health-related quality of life (HRQL) and health utility will be evaluated using the EuroQol 5 Dimensions for Youth (EQ-5D-Y-3L) questionnaire.The EQ-5D is a standardized, utility-based instrument for use as a measure of HRQL and health utility. Similar to the adult version, the EQ-5D-Y-3L comprises 5 questions on mobility, self-care, usual activities, pain/discomfort, and anxiety/ depression. The EQ-5D-Y-3L has been extensively validated in international paediatric populations.

Psychological predictors, specifically psychological readiness to return-to-sport, will be evaluated using the Anterior Cruciate Ligament Return to Sport after Injury (ACL-RSI) questionnaire, which has been shown to be reliable and responsive at the group (study) level in younger populations across all sexes. The ACL-RSI scale has 3 domains: risk appraisal, confidence, and emotions. Greater psychological preparation is indicated by higher scores.

Knee range of motion (ROM) and both anterior-posterior and rotational stability will be evaluated through physical examination (i.e. Lachman and pivot shift tests, respectively). ROM will be measured in the flexion-extension (i.e. sagittal) plane using a goniometer. Anterior-posterior stability will be measured using the Lachman test, given its non-invasive nature, high sensitivity, superiority over the anterior drawer test, and by virtue of being the most reliable clinical method to assess ACL integrity. It will be performed in the supine position, with the extremity in 20-30° of knee flexion, as is commonly described. Similarly, rotational stability will be assessed using the standardized pivot shift test, performed in 30° of knee flexion.

The expert Adjudication Committee will evaluate all graft failures, re-operations and other knee-related adverse events through a process of independent review and consensus, guided by decision rules detailed in the Adjudication Charter (drafted using recommendations from the literature, tested for validity and agreement among the adjudicators, and in use for the pilot study). An adverse event is defined as any symptom, sign, illness, or experience that develops or worsens in severity during the course of the trial.