LESS THAN HALF OF ACL-RECONSTRUCTED ATHLETES ARE CLEARED FOR RETURN TO PLAY BASED ON PRACTICE GUIDELINE CRITERIA: RESULTS FROM A PROSPECTIVE COHORT STUDY

Improved Quadriceps Torque Production With Optimized Biofeedback in Patients After Anterior Cruciate Ligament Reconstruction

Hogg, JA, Barger, NB, Bruce, JR, White, CC, Myer, GD, and Diekfuss, JA. Improved quadriceps torque production with optimized biofeedback in patients after anterior cruciate ligament reconstruction. J Strength Cond Res XX(X): 000–000, 2024—Optimizing performance through intrinsic motivation and attention for learning: prevention rehabilitation exercise play (OPTIMAL PREP) training strategies incorporate motor learning principles to enhance movement acquisition and retention. We aimed to use OPTIMAL PREP biofeedback to evaluate its potential to improve quadriceps and hamstring torque production in patients with anterior cruciate ligament reconstruction (ACL-R). Thirteen subjects 23 ± 19 months post ACL-R completed 5 concentric quadriceps/hamstrings repetitions on an isokinetic dynamometer for each limb and counterbalanced condition at 60°·s−1. For the control condition, subjects were instructed to perform the exercise “as hard and fast as possible.” For the OPTIMAL PREP condition, subjects were additionally told that “Research shows that if you focus on moving the line on the screen (external focus) you will exhibit greater quadriceps output (enhanced expectancies)” and were given the choice of graphical representation for the biofeedback (autonomy support). Quadriceps and hamstrings peak torque, rate of force development, and torque-angle waveforms were analyzed with 2 × 2 RMANOVAs (a priori >0.06). The ACL-R limb demonstrated increased quadriceps peak torque in the OPTIMAL PREP condition than in the control condition ( = 0.13, interaction p = 0.21, pairwise Cohen's d = 0.63). Anterior cruciate ligament reconstruction limb quadriceps deficits remained near terminal extension (14–45°; peak Cohen's d = 0.57, p < 0.001). For hamstrings peak torque, we observed moderate effects for condition (OPTIMAL PREP greater; = 0.10, p = 0.29) and limb (uninvolved greater; = 0.13, p = 0.22). Easily implementable OPTIMAL PREP training strategies improved ACL-R limb quadriceps torque production, resulting in between-limb parity. However, asymmetries still existed near terminal extension.

Composite Score of Readiness (CSR) as a Data Reduction Technique for Monitoring the RTS Process in Footballers following ACL Reconstruction

In recent years, many studies on the safe return to sport (RTS) have been published, but there are still no clear and validated guidelines. After ACL reconstruction between limbs, asymmetry of muscle strength affects knee mechanics during walking and running, and asymmetrical joint kinematics and kinetics are considered as a strong risk factor of musculoskeletal injury. Therefore, proper diagnosis of any motor deficits remaining after ACL reconstruction seems particularly important. The aim of this study was to analyze how many tests should be included in the RTS test battery and which of them are most indicative for functional deficits related to anterior cruciate ligament (ACL) reconstruction. Sixty-five male football players (age 18–25 years) were divided into three groups: ACL group—after ACL rupture and reconstruction, mild injury group—post mild lower limb injuries, and the control group—without injuries. They performed five tests: Functional Movement Screen, Tuck Jump Assessment, Y-balance Test, Hop Test for Distance, and Isokinetic Test. The Composite Score of Readiness (CSR) index was calculated and expressed as the sum of z-scores. The multiple regression model for all tests was calculated, and then redundant variables were excluded. We observed that all tests significantly influenced the final CSR index. The Y-balance Test, Tuck Jump Assessment, and Isokinetic Test for knee flexion influenced the final CSR index the most, which means that these tests are greatly indicative of functional deficits related to ACL reconstruction. The strength of the extensor (quadriceps) muscle and the quadriceps/hamstring ratio appeared to be non-sensitive for testing functional deficits related to ACL reconstruction. If the test battery includes 4–5 tests, it better differentiates the athletes following ACL reconstruction from those after mild injuries, even if they all were cleared to play.

Predicting readiness for return to sport and performance after anterior cruciate ligament reconstruction rehabilitation

BACKGROUND

Determining readiness to return to sport after anterior cruciate ligament (ACL) reconstruction is challenging.

OBJECTIVES

To develop models to predict initial (directly after rehabilitation) and sustainable (one year after rehabilitation) return to sport and performance in individuals after ACL reconstruction.

METHODS

We conducted a multicentre, prospective cohort study and included 208 participants. Potential predictors - demographics, pain, effusion, knee extension, muscle strength tests, jump tasks and three sport-specific questionnaires - were measured at the end of rehabilitation and 12 months post discharge from rehabilitation. Four prediction models were developed using backward logistic regression. All models were internally validated by bootstrapping.

RESULTS

All 4 models shared 3 predictors: the participant's goal to return to their pre-injury level of sport, the participant's psychological readiness and ACL injury on the non-dominant leg. Another predictor for initial return to sport was no knee valgus, and, for sustainable return to sport, the single-leg side hop. Bootstrapping shrinkage factor was between 0.91 and 0.95, therefore the models' properties were similar before and after internal validation. The areas under the curve of the models ranged from 0.74 to 0.86. Nagelkerke's R2 varied from 0.23 to 0.43 and the Hosmer-Lemeshow test results varied from 2.7 (p = 0.95) to 8.2 (p = 0.41).

CONCLUSION

Initial and sustainable return to sport and performance after anterior cruciate ligament reconstruction rehabilitation can be easily predicted by the sport goal formulated by the individual, the individual's psychological readiness, and whether the affected leg is the dominant or non-dominant leg.

Meeting movement quantity or quality return to sport criteria is associated with reduced second ACL injury rate

The purposes of this prospective cohort study were (1) to assess if second anterior cruciate ligament (ACL) injury rate 2 years after ACL reconstruction (ACLR) in those who returned to pivoting sport was associated with meeting (a) quantitative return to sport (RTS) criteria, (b) qualitative RTS criteria, and (c) combined quantitative and qualitative RTS criteria, and (2) to determine why athletes did not return to their preinjury (level of) sport. Athletes after ACLR performed RTS tests immediately before RTS: seven movement quantity (strength and hop test battery) and two movement quality (countermovement jump with LESS score and hop-and-hold test) tests. A 2-year postoperative questionnaire asked for RTS, reasons for not returning to the same (level of) sport and second ACL injuries. One hundred and forty-four athletes (82%) completed the questionnaire and 97 of them returned to a pivoting sport. Seven of these athletes had a second ACL injury. Meeting the hop test battery RTS criterion (absolute risk reduction 11%; p = .047) and hop-and-hold test RTS criterion (absolute risk reduction 15%; p = .031) were both significantly associated with a reduced second ACL injury rate. Meeting combined RTS criteria were not significantly associated with second ACL injury rate. Therefore, RTS tests after ACLR should at least comprise a hop test battery or the hop-and-hold test to reduce second ACL injury risk after return to pivoting sport. Also, one-third of all athletes mentioned fear of reinjury as the main reason for not returning to their preinjury (level of) sport. This psychological component should be taken seriously and discussed during rehabilitation.

The Non-injured Leg Can Be Used as a Reference for the Injured Leg in Single-legged Hop Tests

BACKGROUND

Single-legged hop tests are frequently used in substantiating return to sport decisions following lower extremity injury. Evidence for using the non-injured leg as a reference for the injured leg in the return to sport decision-making at the criterion-based point of return to sport following lower extremity injury is lacking.

PURPOSE

To compare absolute values in single-legged hop tests between the non-injured leg of athletes returning to high-impact sports after lower extremity injury and the matched leg of healthy athletes.

STUDY DESIGN

Cross-sectional study.

METHODS

One hundred and sixty-nine athletes returning to high-impact sports after lower extremity injury and 169 matched healthy athletes executed five single-legged hop tests. Differences between athletes returning to high-impact sports after lower extremity injury and matched healthy athletes on five single-legged hop tests were analyzed using paired t-tests.

RESULTS

There were no statistically significant differences between the non-injured leg of athletes returning to sport and the matched leg of healthy athletes. Effect sizes ranged from 0.05 to 0.14 indicating negligible effects.

CONCLUSION

Clinicians can use the non-injured leg as a reference for the injured leg in single-legged hop tests for deciding on return to high-impact sports after lower extremity injuries.

LEVEL OF EVIDENCE

3b.