ACL tears, as discussed previously (here & here) are not career ending but require some time and adaptation before returning to play. Therapists and coaches are left with guidelines and no specific protocols when rehabilitating a torn ACL. Few concrete methods exist with signposts along the way.

Della Villa et al. (2012) set out to change that. Using the Knee Outcome Survey-Sports Activity Scale (KOS-SAS) on field with every workout and training sessions, coaches were able to get a handle on how athletes were feeling and could set benchmarks for players’ improvement, seeing changes over time.

The KOS-SAS is a set of 15 self-report questions on a 6 point scale. Each question is scored from 0-5. While not an objective measure, it is easy to administer and coaches can easily track progress with standardised strength & rate of force development measures (jump height, 40 yard time, L-drill time and other objective measures) and pair the results with the KOS-SAS to determine when players can return to play. In 2001, Marx et al. completed a reliability study on several self-report questionnaires and found that the KOS-SAS showed .70-.85 for construct validity  (p <.05) when compared with the SF-36the ADLS or the Lysholm scale. So we know this is a valid self-report questionnaire when used as intended.

In the study, Della Villa used the KOS-SAS, isokinetic strengthening and general aerobic conditioning with standard rehabilitation for 50 soccer players’ post-ACL reconstruction. Average return to training was 90 days with the average return to play 180 days. Players showed significant improvement (P<.01) under the KOS-SAS, starting at 79 +/-15% and rising to 96 +/-7%. This shows that in 90 days of post-surgical rehabilitation and on-field training, an average increase in function of 17 points was found. Now a coach can say to a player, with some degree of comfort; “You are not playing a game until you have reached at least a 95 on the KOS-SAS.” The coach could then have a reasonable expectation that the player would be strong enough to return to play with minimal chances of re-injury that season.

As discussed previously, ACL rehab should include a neuro-muscular warm up, terminal knee extension, hamstring strengthening, running mechanics (focused on turning), plyometrics, and rate of force development training! All of these, introduced progressively and over a period of time (note that it took 180 days from hospital release to return to a game) will help maximize the chances that the player involved will have a successful outcome when returning to play.