Table 1.
Outcome measurement and interpretation
| Construct (measure) | Time-point(s) | Assessment method | Interpretation |
| Evidence of ACL healing on MRI (ACLOAS MRI grading system)21 | 3 months; 6 months |
MRI interpretation was performed independently by three experienced musculoskeletal radiologists (RS, PL and AVDH). A consensus meeting resolved any discrepancies | ACLOAS grades: 0=normal ligament with hypointense signal and regular thickness and continuity; 1=thickened ligament and/or high intraligamentous signal with normal course and continuity; 2=thinned or elongated but continuous ligament; 3=absent ligament or complete discontinuity21 |
| Self-reported knee function (Lysholm Scale)22 | Median (IQR): 12 months (7–16 months) | Self-reported questionnaire | Scored out of 100 across 8 domains: pain, instability, locking, swelling, limping, stair climbing, squatting and the need for gait support.23 A score of 84 is considered ‘good’. A score of >94 is considered ‘excellent’. A lower score indicates increased severity of symptoms and worse function.24 Acceptable reliability, validity and responsiveness for use in ACL-injured individuals25 |
| Knee-related QOL (ACLQOL)26 | Median (IQR): 12 months (7–16 months) | Self-reported questionnaire | The 32-item questionnaire contains five domains (Symptoms & Physical Complaints, Work-Related Concerns, Recreation Activities & Sport Participation or Competition, Lifestyle, Social & Emotional Aspects) and is scored out of 100 (overall score and individual domain scores) with a lower score indicating worse knee-related QOL.26 Valid, reliable and responsive for use in ACL injured patients17 27 |
| Passive knee laxity (Lachman’s test and pivot- shift test) | 3 months (Lachman’s test); 6 months (pivot-shift test) |
Both tests were performed by one of two experienced sports and exercise medicine physicians (TC and RD) who were not blinded to the treatment | Lachman’s test was graded relative to the contralateral knee (no side-to-side difference; end-point with side-to-side difference and no end-point).28 Pivot shift test was graded based on the quality of the lateral pivot-shift manoeuvre (normal=no glide or jerk detected; glide=a ‘gliding’ motion (IKDC grade 129); jerk=locked subluxation (described as grade 3 instability by the IKDC classification29); or a ‘jerking’/clunking movement pattern (IKDC grade 2 instability29)) |
| Return to pre-injury sport | 12 months | Self-reported during a clinical visit or via telephone interview | Patients reported whether they had returned to pre-injury sport (information collected included the type and level of sport that they returned to) |
ACL, anterior cruciate ligament; ACLOAS, Anterior Cruciate Ligament OsteoArthritis Score; ACLQOL, Anterior Cruciate Ligament Quality Of Life Questionnaire; IKDC, International Knee Documentation Committee; QOL, quality of life.