Monday Memo Oct 5, 2020: The Importance of Return to Sport (RTS) testing in ACL Rehabilitation

Phil Forsythe, SPT ’21

Week two of the NFL came and went filled with injuries in one of the worst weekends for players and fantasy football owners alike. For Saquon Barkley of the New York Giants and Nick Bosa of the San Francisco 49ers’, their 2020 campaigns came to a halt with one of the worst injuries a professional athlete can suffer: torn ACLs.  In a review of Orthopaedic Surgeries effect on athletes’ careers in the NFL, the average rehabilitation period for ACLRs was 378.1 days or just over a year [1]. These are some of the most elite athletes in the country with some of the best professional surgeons, physical therapists, and strength and conditioning specialists, and yet, it still takes them on average a year to return to the field.

That raises an important question: how good are the outcomes for physical therapists treating high school and college athletes in the outpatient orthopaedic setting? Not great. In a 2014 study looking at the incidence of a second ACL injury two years after return to sport in 78 patients, they reported a second ACL injury rate of 29.5% with 20.5% occurring on the contralateral ACL [2]. Surgeons and physical therapists alike have made progress on recognizing some of the most important factors from the literature to reduce reinjury rates including symmetrical quadricep indices and time until return to sport. In general, it appears that every month RTS is delayed up to the ninth, the likelihood for reinjury is reduced by 51% compared to the previous month (3).

Every new graduate in the outpatient orthopaedic setting will eventually see the referral to evaluate and treat a post-operative ACL patient. Alongside that referral they will receive a protocol outlining the goals for range of motion, strength, jogging, jumping, running, cutting/pivoting, and finally return to sport. The problem with only adhering to your protocol is you are trying to eliminate the personal aspect from your athlete’s rehab. The protocol should serve as your guide, but it should never paralyze your ability to assess what your athlete is showing you on the day to day basis. Every athlete should earn the right to the next stage of their rehab until they are ready to step back onto that field. Otherwise, you are potentially doing them a disservice. At Pitt, one of the mantras we get taught is to test early and test often. While that doesn’t mean you start doing hopping tests before they are jogging, one of your goals should be to assess strength of the quadriceps compared to the uninvolved side before the patient earns the right to progress in their rehab. Communicating early with the surgeon to align recommendations with objective goals ensures there is no miscommunication during checkup visits.

What is the next step when nine months passes by, and your athlete feels that they are ready to start playing again? As physical therapists, we need options that will accurately assess the demands of their sport and provide an evaluation that clears an athlete for play. Researchers are still working on the most optimal battery of return to sport tests, but they have shown that meeting a comprehensive RTS criterion can significantly reduce reinjury rates in athletes who passed versus athletes who failed [3].

Here’s an example of the battery used in the Delaware-Oslo ACL cohort study (>90% symmetry for all tests is considered a pass) [3].

1. Quadriceps Strength Testing: Isokinetic Concentric (Biodex) – The Biodex is considered the gold standard for testing quadriceps muscle strength, but it is also extremely cost prohibitive for typical outpatient settings. A handheld dynamometer can produce a more cost-effective assessment, and even 1-rep maximum testing on the leg press is better than no strength assessment. Quadriceps symmetry is extremely important; this needs to be tested before you should be comfortable letting a patient return to sport.

2. Four Single Legged Hop Tests – There are many different options for single legged hop tests: single leg hop for distance, triple crossover hop, triple hop, 6 meter timed hop, lateral and medial single leg hops. Symmetry between involved and uninvolved in terms of distance or time is what you are measuring.

3. Two Objective Outcome Scores – KOS-ADLS and Global Rating Scale. These outcomes tell a lot about how the patient perceives their knee and overall function. Another great outcome score would be the ACL-RSI; this outcome gives a quick measure of the patient’s fears about returning to sport and the specific mechanism of injury for their knee [4].

RTS testing is an integral element to ensuring that you are providing the best possible opportunity to prevent a second ACL injury. While there are additional considerations on whether athletes should progress through a tapered return to live, full contact sport, RTS testing is the bare minimum we need to be doing as clinicians before signing off on our end.

Nine months minimum is one of the longest rehabilitation times in physical therapy. By making your RTS decision objective and measurable, you could prevent that athlete’s return to physical therapy for a second injury.

1. Mai HT, Alvarez AP, Freshman RD, et al. The NFL Orthopaedic Surgery Outcomes Database (NO-SOD): The Effect of Common Orthopaedic Procedures on Football Careers. The American Journal of Sports Medicine. 2016;44(9):2255-2262.

2. Paterno MV, Rauh MJ, Schmitt LC, Ford KR, Hewett TE. Incidence of Second ACL Injuries 2 Years After Primary ACL Reconstruction and Return to Sport. Am J Sports Med. 2014 Jul;42(7):1567-73

3. Grindem H, Snyder-Mackler L, Moksnes H, Engebretsen L, Risberg MA. Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study. Br J Sports Med. 2016 Jul;50(13):804-8.

4. Webster KE, Feller JA. Development and Validation of a Short Version of the Anterior Cruciate Ligament Return to Sport After Injury (ACL-RSI) Scale. Orthop J Sports Med. 2018 Apr 4;6(4)