ACL Return to Sport Protocols
In 2023, where do we stand concerning ACL return-to-sport protocols? Traditionally, the
expected timeframe for returning to sports activities after suffering an ACL tear and
completing the subsequent rehabilitation process ranges from 9 to 12 months, or even
longer. However, there exists a state of confusion surrounding the appropriate battery of
tests, strength assessments, and the optimal time for granting clearance for a return to
sports.
Beischer et al. conducted a study revealing that returning to strenuous knee-related
sports before the 9-month mark following ACL reconstruction was associated with a
roughly 7-fold increase in the likelihood of experiencing a second ACL injury. Given the
wealth of available data, it raises the question: why are we still lagging in the realm of
return-to-sport testing?
I am Dr. Evan Motlong, and I am here to delve into the guidelines that should be
followed when conducting return-to-sport testing for our athletes and active clients. In
many physical therapy clinics, the focus tends to be on conducting a brief manual
muscle test and a battery of hop tests to determine a patient’s eligibility for returning to
sports. Let’s begin by clarifying what return-to-sport (RTS) testing entails. RTS testing is
defined as a set of assessments designed to encompass various risk factors. A
comprehensive RTS test battery should include, at the very least, strength tests, hop
tests, and assessments of movement quality.
In the United States, a striking 56% of therapists rely solely on manual muscle testing
as their method for evaluating strength. This is a matter of concern as manual muscle
testing, using the Medical Research Council scale, comes with several limitations,
including poorly defined distinctions between grades “4” and “5”. Such an approach not
only puts our athletes at risk of failure and potential re-injury but also falls short of our
responsibility as evidence-based practitioners. To provide the best care, we must stay
updated with current research data.
For research purposes, isokinetic dynamometry is often employed to assess the
strength of the quadriceps and hamstrings. However, practicality issues arise in clinical
settings due to the high cost, lack of portability, and space requirements of isokinetic
devices. A more clinically viable alternative is hand-held dynamometry or the utilization
of equipment such as a leg press or leg extension machine for 1, 3, 5, or even 10-rep
max testing.
The Limb Symmetry Index (LSI) is a crucial metric, defined as the ratio between the
scores of the involved and uninvolved limbs, expressed as a percentage. An LSI of
90% is typically used as a cutoff score. For recreational and non-pivoting sports, an
LSI of 90% may suffice, but for pivoting/contact/competitive athletes, a 100% LSI for
both knee extensor and knee flexor muscle strength is recommended. However, issues
arise here: 1) only 14% of patients achieved an LSI of 100% for strength tests at the 2-
year post-ACLR mark, raising doubts about its feasibility in daily practice; 2) the LSI
assumes that the uninjured leg can serve as an adequate reference for strength, which
may not be the case post-ACLR due to bilateral deficits.
I find the following table to be extremely valuable for therapists in establishing criteria for
return to sports.
Additionally, I advocate for the inclusion of the Vail Sport Test™, which involves dynamic
multiplanar functional activities against the resistance of a sportcord. This test not only
assesses muscle endurance but also evaluates the qualitative ability to control the lower
extremity during these tasks. Another valuable addition is the lateral step-down test,
which assesses muscular endurance and movement quality. From a strength
perspective, I have found that conducting isometric strength testing at 90 and 45
degrees of knee extension, along with a 3 or 5-rep max on a leg press or leg extension
machine, is a practical alternative in the absence of a Biodex machine, which is often
inaccessible.
I hope you find this information helpful and educational. Please don’t hesitate to reach
out via email or visit us at one of our clinics in Brickell, Miami or Miami Beach for further information.
Dr. Evan Motlong, PT, DPT, CSCS, XPS
drevan@asrsportsmedicine.com
References:
1. Burgi CR, Peters S, Ardern CL, et al. Which criteria are used to clear patients to
return to sport after primary ACL reconstruction? A scoping review. Br J Sports
Med. 2019;53:1154-1161. doi:10.1136/bjsports-2018-099982
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;42(7):1567-1573. doi:10.1177/0363546514530088
3. Wetters N, Weber AE, Wuerz TH, Schub DL, Mandelbaum BR. Mechanism of
injury and risk factors for anterior cruciate ligament injury. Oper Tech Sports Med.
2016;24(1):2-6. doi:10.1053/j.otsm.2015.09.001