Passing return-to-sport criteria and landing biomechanics in young athletes following anterior cruciate ligament reconstruction

Return to Sport After Pediatric Anterior Cruciate Ligament Reconstruction: A Systematic Review of the Criteria

BACKGROUND

Postoperative rehabilitation is an important component of recovery after anterior cruciate ligament (ACL) reconstruction (ACLR), facilitating successful return to sport (RTS) by reducing risk factors for repeat injury.

PURPOSE

This systematic review aimed to determine the best protocol for RTS after ACLR in children.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

PubMed, Embase, PEDro, SPORTDiscus, and Web of Science databases were searched from October 3, 2014, to November 3, 2022. The inclusion criteria were the pediatric population (<18 years old) after ACLR with clear RTS criteria and/or mean/median time to RTS. Multiligament knee injuries were excluded from this study. The methodologic quality of the included articles was assessed using the methodological index for non-randomized studies (MINORS). The highest possible score was 24 points for comparative studies (ie, a study comparing 2 protocols or more). Noncomparative studies or studies with a single protocol could score a maximum of 16 points as assessed by the MINORS score.

RESULTS

The search yielded 1816 titles, and 24 were retained based on the inclusion and exclusion criteria. Every study was published between 2015 and 2022. Among the 24 studies included, 13 were retrospective and 11 were prospective. The mean MINORS score for the noncomparative studies was 13 of 16 (n = 23) and 23 of 24 for the comparative study (n = 1). The studies were categorized into unspecified clearance (n = 10), milestone based (n = 13), and combined time and milestone (n = 1). A total of 1978 patients (57% female) were included in the review. The mean age at ACLR was 14.7 years. The most common endpoint used was graft rupture (0% to 35%). In the unspecified group, the quickest RTS was 5.8 months and the longest was 9.6 months. Statistically significant risk factors for ACL reinjury included younger age and earlier RTS. The latter was a significant contributor to graft failure for combined time-based and milestone-based RTS. In the milestone-based group, the most common criteria were ≥90% limb symmetry measured using hamstring strength, quadriceps strength, and/or hop tests. The mean RTS time was 6.8 to 13.5 months.

CONCLUSION

RTS should be delayed, when possible, especially in the younger population. A combination of quantitative tests and qualitative tests is also recommended. However, optimal RTS criteria have yet to be determined. Future prospective studies should focus on comparing the different times and milestones currently available.

A comparison between physical therapy clinics with high and low rehabilitation volumes of patients with ACL reconstruction

BACKGROUND

Treatment volume can impact outcomes after surgical procedures of the knee between surgeons with high- and low-patient-volumes. However, the difference between physical therapeutic clinics with high- and low-volumes has not been widely researched. This registry study aims to investigate how patient volume affects knee function outcomes after anterior cruciate ligament (ACL) reconstruction at physical therapy (PT) clinics in terms of odds for a second ACL injury, return to pre-injury level of activity, perceived knee function, and recovery of strength and hop performance.

METHOD

Data were extracted from the Project ACL, a local rehabilitation registry. High- and low-volume clinics were defined based on the number of patients who attended different clinics. High-volume clinics were defined as those with > 100 patient registrations in Project ACL during the study period while low-volume clinics were those with ≤ 100 patient registrations. High- and low-volume clinics were compared, based on muscle function and patient-reported outcomes across 4 follow-ups, 2-, 4-, 8-, and 12 months, during the first year after ACL reconstruction, and odds of second ACL injury up to 2 years after ACL reconstruction.

RESULT

Of the 115 rehabilitation clinics included, 111 were classified as low-volume clinics and included 733 patients, and 4 as high-volume clinics which included 1221 patients. There were 31 (1.6%) second ACL injuries to the ipsilateral or contralateral side within the first 12 months and 68 (4.0%) within 2 years. No difference in the incidence of a second ACL injury, within 12 months follow-up odds ratio (OR) 0.95 [95% CI 0.46-1.97] or within 2 years follow-up OR 1.13 [95% CI 0.68-1.88], was found between high- and low-volume clinics. There were early (2 months) and non-clinically relevant differences in patient-reported outcomes (PROs) and physical activity levels early after ACL reconstruction in favor of high-volume clinics. One year after ACL reconstruction, no differences were observed between high- and low-volume clinics in terms of PROs, muscle function, and return to pre-injury level of activity.

CONCLUSION

No clinically relevant difference in the incidence of secondary ACL injuries in patients who underwent rehabilitation after ACL reconstruction at high- or low-volume physical therapist clinics was found. In addition, no clinically relevant differences in outcomes were found during the first year in terms of patient-reported outcomes, recovery of muscle function, or return to pre-injury level of activity.

Beyond peak torque: Longitudinal analysis of angle-specific isokinetic knee torques in collegiate athletes post-ACLR

OBJECTIVES

To investigate changes in angle-specific knee extensor torque between limbs from 4 to 12 months post-anterior cruciate ligament reconstruction(ACLR) in Division I collegiate athletes at two different isokinetic velocities.

DESIGN

Case-series study.

SETTING

Laboratory-based.

PARTICIPANTS

Isokinetic knee flexion and extension assessments of 17 athletes (11 female) at 4, 8, and 12 months after ACLR with bone-patellar tendon-bone autograft were evaluated.

MAIN OUTCOME MEASURES

Angle-specific curve analyses were performed using statistical parametric mapping for torque data obtained between 14 and 101° at 60°/s and 240°/s velocities.

RESULTS

At 60°/s, knee extensor torque of the operated limb increased between 4 and 8 months (18-101°,p < 0.001), 4 and 12 months (28-101°,p < 0.001), and 8 and 12 months post-surgery (62-70°,p = 0.002, and 79-90°,p < 0.001). Knee extensor torque was lower in the operated limb compared to the non-operated limb at 4 (47-97°,p < 0.001) and 8 months (65-90°,p < 0.001) for 60°/s, at 4 (21-89°,p < 0.001) and 8 months (50-77°,p < 0.001) for 240°/s, with no between-limb differences at 12 months post-ACLR for both velocities.

CONCLUSIONS

Operated limb knee extensor torque increased throughout the majority of knee range of motion from 4 to 12 months post-ACLR at both isokinetic velocities, while non-operated limb torque only improved through a reduced arc of motion in greater knee flexion angles.

Novel Use of an Accelerometer to Assess Load Asymmetry Over Time After Hip Resurfacing Arthroplasty

INTRODUCTION

There is limited knowledge regarding usage of wearable technology to guide return to sport after hip resurfacing arthroplasty (HRA). This study evaluated the use of accelerometers to identify when symmetry is restored between operative and non-operative limbs.

METHODS

A total of 26 primary HRA patients performed five validated physical tests before, 3 and 6 months after HRA: broad jump, double leg vertical jump (DLVJ), hop test, lateral single leg jump (LSLJ), and vertical single leg jump (VSLJ). Impact load and average intensity data (g-force units) were collected using accelerometers. Strength data (pounds (lbs.)) for internal and external rotation was collected with a dynamometer. Univariate and correlation analyses analyzed interlimb asymmetries.

RESULTS

At pre-operation, there were significant impact load asymmetries for DLVJ (P=.008), hop test (P=.021), and LSLJ (P=.003), and intensity asymmetry for DLVJ (P=.010) and LSLJ (P=.003). At 3 months, there was impact load asymmetry for DLVJ (P=.005) and LSLJ (P=.005), and intensity asymmetry for broad jump (P=.020), hop test (P=.042), and LSLJ (P=.005). There were significant strength asymmetries at pre- and 3 months post-operation for internal (P=.013) and external rotation (P=.037). All significant asymmetries indicated the non-operative leg had greater output. No significant asymmetries were found for any exercises at 6 months post-operation. An increase in Harris Hip Score was significantly associated with a decrease in impact asymmetry (r_s = -0.269, P=.006).

DISCUSSION AND CONCLUSION

Impact loads and strength reach interlimb symmetry at 6 months post-HRA. Wearable accelerometers provide useful metrics to distinguish limb asymmetries for recovery monitoring.

A scoping review of postoperative return to sport criteria and protocols for patients with femoroacetabular impingement syndrome

PURPOSE

To identify the objective criteria and guidelines utilized to determine if patients diagnosed with FAIS can safely return to sport following hip arthroscopy.

METHODS

The electronic databases MEDLINE Ovid, EMBASE Ovid, and CINAHL were searched to identify eligible studies. Details of study design, sample size, primary diagnosis, and return to sport protocol, duration, and rate were collected by two reviewers, independently.

RESULTS

Sixty-two studies were selected for full text review of which 14 were included in the final analysis. Of these, nine were clinical commentaries and five were retrospective cohort studies. Three types of rehabilitation guidelines are currently utilized postoperatively: 4-phase, 5-phase, and 6-phase protocols. Although all 14 studies recommend using various types of outcome measures to evaluate a patient's ability to return to sport, only eleven outlined the specific outcome criteria they must achieve to do so. The most utilized outcome measures are the hip outcome score, active and passive range of motion tests, gait analysis, single- and double-leg squat tests, and the Vail hip sports test. Criteria across all three types of protocols was variable, but they all evaluated the same international classification of disability and function constructs described by the World Health Organization: body function, body structure limitations, and activity capacity limitations.

CONCLUSIONS

There is no consensus on the optimal methods of evaluating a patient's readiness to return to sport after undergoing hip arthroscopy, with most criteria focused on expert opinion. Performance-based return to sport outcome criteria is not clearly defined, and validated outcome measures are not being used for FAIS patients post hip arthroscopy. Lastly, well-conducted prospective cohort studies using validated outcome measures and objective definitions of return to sport are needed to consistently identify signs that are prognostic of safe return to sport.

Altered movement strategy during functional movement after an ACL injury, despite ACL reconstruction

Knee joint functional deficits are common after anterior cruciate ligament (ACL) injury, but different assessment methods of joint function seem to provide contradicting information complicating recovery monitoring. We previously reported improved perceived knee function and functional performance (forward lunge ground contact time) in patients with an ACL injury from pre to 10 months post ACL reconstruction without improvement in knee-specific biomechanics. To further investigate this discrepancy, we additionally analyzed knee extensor and flexor muscle strength, and movement quality in the forward lunge (subjective and objective evaluations) and performed a full lower limb biomechanical analysis of the forward lunge movement. We included 12 patients with an ACL injury (tested before and after ACL reconstructive surgery) and 15 healthy controls from the previous study to the current investigation. Outcome measures were obtained pre and ~11 months post ACL reconstruction for the patients and at a single time point for the controls. Objective movement quality in the patients with an ACL injury showed an improvement from their pre reconstruction surgery visit to the post reconstruction visit but this was not observable in the subjective evaluation. Knee extensor muscle strength declined after the ACL reconstruction by 29% (p = 0.002) and both knee extensors (p < 0.001) and flexors (p = 0.027) were weaker in the patients post ACL reconstruction compared to healthy controls. ACL injured patients had an altered movement strategy in the forward lunge with reduced knee extensors contribution and increased hip extensor contribution compared to the controls both before and after the reconstruction. The altered movement strategy was associated with knee extensor muscle strength. This explorative study with a limited sample size found that clinicians should be aware that significant functional deficits in the knee extensor muscles, both in isolated muscle strength testing and during a functional movement, may be present although patients perceive an improvement in their knee function and present good functional performance without obvious movement quality issues.

Identification and Predictors of Age-Relevant and Activity-Relevant Hop Test Targets in Young Athletes After Anterior Cruciate Ligament Reconstruction

CONTEXT

Performance symmetry between limbs (limb symmetry index [LSI] ≥ 90%) on a battery of single-leg hop tests is recommended to inform return-to-sport (RTS) decisions after anterior cruciate ligament (ACL) reconstruction (ACLR). Achieving current hop test symmetry values has not been associated with future clinical outcomes. The identification of age-relevant and activity-relevant target values to benchmark the hop test performance of young athletes post-ACLR may provide greater specificity and clinical relevance for interpretation of hop test data.

OBJECTIVE

To identify single-leg hop test-target values for individual-limb performance and symmetry between limbs for athletes without a history of ACL injury and evaluate the proportion of young athletes post-ACLR who met the newly derived target values at the time of RTS clearance. The secondary objective was to test the hypothesis that better function and strength would be associated with achieving the newly derived hop test target values.

DESIGN

Cross-sectional study.

SETTING

Pediatric medical center and academic medical center.

PATIENTS OR OTHER PARTICIPANTS

A total of 159 young athletes (age = 16.9 ± 2.2 years) at the time of RTS clearance after primary, unilateral ACLR and 47 uninjured control athletes (age = 17.0 ± 2.3 years).

MAIN OUTCOME MEASURE(S)

All participants completed a single-leg hop test battery (single hop, triple hop, and crossover hop for distance [cm], and 6-m timed hop [seconds]). Raw distance values were normalized by body height, and LSI (%) was calculated for each hop test. Target values were defined as the lower bound of the 95% CI for each hop test, using control group data. Participants with ACLR also completed the Knee injury and Osteoarthritis Outcome Score subscales and a quadriceps femoris strength (newton meters/kilogram) assessment. Logistic regression determined predictors of achieving hop test target values in the ACLR group among injury, function, and strength data (P < .05).

RESULTS

In the ACLR group, 79% to 84% of participants met the 90% LSI threshold on each hop test. They achieved the target values for surgical-limb performance in the following proportions (% participants): single hop = 29%, triple hop = 24%, crossover hop = 30%, 6-m timed hop = 18%, all hops= 12%. Also, they met the target values for LSI in the following proportions: single hop = 43%, triple hop = 48%, crossover hop = 50%, 6-m timed hop = 69%, all hops = 25%. The only predictor of achieving all hop test targets for surgical-limb performance was greater surgical-limb quadriceps femoris strength (odds ratio = 4.10, P = .007). We noted a trend toward quadriceps femoris strength LSI ≥ 90% (odds ratio = 2.44, P = .058) as a predictor for meeting all hop test symmetry targets.

CONCLUSIONS

At the time of RTS post-ACLR, only a small proportion of young athletes achieved the age-relevant and activity-relevant single-leg hop test targets for surgical-limb performance or symmetry between limbs, even though a majority met the traditionally recommended 90% LSI threshold on hop tests.