The Importance of Patient Sex in the Outcomes of Anterior Cruciate Ligament Reconstructions: A Systematic Review and Meta-analysis

Anterolateral rotatory instability in vivo correlates tunnel position after anterior cruciate ligament reconstruction using bone-patellar tendon-bone graft

AIM

To quantitatively assess rotatory and anterior-posterior instability in vivo after anterior cruciate ligament (ACL) reconstruction using bone-patellar tendon-bone (BTB) autografts, and to clarify the influence of tunnel positions on the knee stability.

METHODS

Single-bundle ACL reconstruction with BTB autograft was performed on 50 patients with a mean age of 28 years using the trans-tibial (TT) (n = 20) and trans-portal (TP) (n = 30) techniques. Femoral and tibial tunnel positions were identified from the high-resolution 3D-CT bone models two weeks after surgery. Anterolateral rotatory translation was examined using a Slocum anterolateral rotatory instability test in open magnetic resonance imaging (MRI) 1.0-1.5 years after surgery, by measuring anterior tibial translation at the medial and lateral compartments on its sagittal images. Anterior-posterior stability was evaluated with a Kneelax3 arthrometer.

RESULTS

A total of 40 patients (80%) were finally followed up. Femoral tunnel positions were shallower (P < 0.01) and higher (P < 0.001), and tibial tunnel positions were more posterior (P < 0.05) in the TT group compared with the TP group. Anterolateral rotatory translations in reconstructed knees were significantly correlated with the shallow femoral tunnel positions (R = 0.42, P < 0.01), and the rotatory translations were greater in the TT group (3.2 ± 1.6 mm) than in the TP group (2.0 ± 1.8 mm) (P < 0.05). Side-to-side differences of Kneelax3 arthrometer were 1.5 ± 1.3 mm in the TT, and 1.7 ± 1.6 mm in the TP group (N.S.). Lysholm scores, KOOS subscales and re-injury rate showed no difference between the two groups.

CONCLUSION

Anterolateral rotatory instability significantly correlated shallow femoral tunnel positions after ACL reconstruction using BTB autografts. Clinical outcomes, rotatory and anterior-posterior stability were overall satisfactory in both techniques, but the TT technique located femoral tunnels in shallower and higher positions, and tibial tunnels in more posterior positions than the TP technique, thus increased the anterolateral rotation. Anatomic ACL reconstruction with BTB autografts may restore knee function and stability.

Younger Patients and Men Achieve Higher Outcome Scores Than Older Patients and Women After Anterior Cruciate Ligament Reconstruction

BACKGROUND

There is some evidence that functional performance and validated outcome scores differ according to the gender, age, and sport participation status of a patient after anterior cruciate ligament (ACL) reconstruction. However, the impact of these three factors, and interaction among them, has not been studied across a large relatively homogeneous group of patients to better elucidate their impact.

QUESTIONS/PURPOSES

We reviewed a large cohort of patients who had undergone ACL reconstruction to determine if ROM, knee laxity, objective performance measures, and validated outcome scores differed according to (1) gender; (2) age; and (3) sport participation status.

METHODS

This was a retrospective analysis of prospectively collected data. Between 2007 and 2016, we performed 3452 single-bundle ACL reconstructions in patients who participated in sport before ACL injury. Of those, complete followup (including preoperative scores and scores at 1 year after surgery; mean, 14 months; range, 12-20 months) was available on 2672 (77%) of patients. Those lost to followup and those accounted for were not different in terms of age, gender, and sports participation at baseline. The study group consisted of 1726 (65%) men and 946 (35%) women with a mean ± SD age of 28 ± 10 years. For these patients, the following measures were obtained: knee ROM (flexion and extension deficit), instrumented knee laxity, single and triple hop for distance limb symmetry index (LSI), International Knee Documentation Committee (IKDC) subjective evaluation, and Single Assessment Numeric Evaluation score. Mean scores and measures of variability were calculated for each outcome measure. Comparisons were made among gender, age, and sport status.

RESULTS

Men had less knee laxity after reconstruction (men 1.1 ± 2.2 mm, women 1.3 ± 2.4 mm; mean difference 0.2 mm [0.1-0.4], p < 0.001), greater limb symmetry (single limb hop men: 94% ± 12%, women 91% ± 13%, mean difference 3% [2%-4%], p < 0.001), and higher IKDC scores than did women (men 84 ± 12, women 82 ± 12, mean difference 2 [1-3], p < 0.001). With the exception of instrumented laxity, all outcome measures showed reduced deficits and higher scores in younger patients. This was most marked for LSI scores between the youngest and oldest aged patient groups (crossover hop: < 16 years 99% ± 10%, > 45 years 90% ± 16%, mean difference: 9 [5-11], p < 0.001). Patients who had returned to their preinjury sport also scored higher and had smaller deficits for all outcomes except ROM compared with patients who had not returned to sport at the time of followup (IKDC subjective: returned 90 ± 9, no sport 79 ± 12, mean difference 11 points [9-12], p < 0.001; single limb hop: returned 97 ± 10, no sport 91 ± 14, mean difference 6% [5%-7%], p < 0.001).

CONCLUSIONS

This study showed that some of the most commonly used functional performance and validated clinical scores for ACL reconstruction are superior for patients who are younger, male, and have returned to preinjury sport. Reference to these data allows clinicians to more effectively evaluate a patient based on their age, gender, and sport status when making return to sport and rehabilitation decisions.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Joint awareness after ACL reconstruction: patient-reported outcomes measured with the Forgotten Joint Score-12

PURPOSE

To measure joint awareness in patients who have undergone anterior cruciate ligament (ACL) reconstruction and to investigate medium- and long-term results of the procedure.

METHODS

All patients who had undergone ACL reconstruction with the same arthroscopic surgical technique at our institution between 2011 and 2014 (medium-term follow-up group (Group I)) or between 2000 and 2005 (long-term follow-up group (Group II)) were considered for inclusion in the study. A group of healthy controls were recruited to obtain reference values for the FJS-12 (Forgotten Joint Score-12). Propensity score matching was applied to improve comparability of patients and healthy controls in terms of sex and age.

RESULTS

Fifty-eight patients of the Group I (mean follow-up 31.5 (SD13.4) months, range 12-54), 57 patients of the Group II (mean follow-up 139 (SD15.2) months, range 120-179), and the healthy control samples (100 individuals) were analysed. Significantly lower FJS-12 was found in both groups (Group I: 71.6 and Group II: 70.1), compared to the two matched control groups (88.1 and 90.0).

CONCLUSIONS

The concept of joint awareness was successfully applied to evaluate medium- and long-term results of ACL reconstruction. The clinical relevance of this study is that it extends the construct of joint awareness as a patient-reported outcome parameter to ACL reconstruction surgery.

LEVEL OF EVIDENCE

Level III.

MRI findings of knee abnormalities in adolescent and adult volleyball players

Background

To longitudinally and cross-sectionally evaluate knee abnormalities by sex and age in adolescent and adult volleyball athletes over 2 years using magnetic resonance imaging (MRI).

Methods

Thirty-six high-level volleyball athletes (18 adolescents: 56% female, mean age 16.0 ± 0.8 years; and 18 adults: 50% female, mean age 46.8 ± 5.1 years) were imaged by MRI at BL and at 2-year follow-up (FU). Prevalence and severity of cartilage lesions, subarticular bone marrow lesions (BMLs), subarticular cysts, osteophytes, and ligament and meniscus integrity were evaluated by sex and by age cohort (adolescents and adults) using the whole-organ MRI score (WORMS).

Results

There were no significant longitudinal changes in any of the features within any of the sex or age groups. No significant differences were found in overall prevalence or severity of any of the features between males and females, although at FU, males had a significantly higher prevalence of osteophytes in the medial femorotibial joint (MFTJ) than females (p=0.044). Compared to adolescents, adult volleyball players had a significantly greater prevalence and severity of cartilage lesions (p<0.001 for both), BMLs (p=0.0153 and p=0.005), and osteophytes (p≤0.003 and p<0.001), and more severe meniscal lesions (p≤0.021).

Conclusion

We found significant differences in the prevalence and severity of knee abnormalities between adolescent and adult volleyball players, but no overall differences by sex. These findings lay the groundwork for further investigations with larger cohorts and longer FU times to determine whether or not these knee abnormalities are associated with the development of OA.

Cost of Outpatient Arthroscopic Anterior Cruciate Ligament Reconstruction Among Commercially Insured Patients in the United States, 2005-2013

BACKGROUND

Despite the significance of anterior cruciate ligament (ACL) injuries, these conditions have been under-researched from a population-level perspective. It is important to determine the economic effect of these injuries in order to document the public health burden in the United States.

PURPOSE

To describe the cost of outpatient arthroscopic ACL reconstruction and health care utilization among commercially insured beneficiaries in the United States.

STUDY DESIGN

Economic and decision analysis; Level of evidence, 3.

METHODS

The study used the Truven Health Analytics MarketScan Commercial Claims and Encounters database, an administrative claims database that contains a large sample (approximately 148 million) of privately insured individuals aged <65 years and enrolled in employer-sponsored plans. All claims with Current Procedural Terminology (CPT) code 29888 (arthroscopically aided ACL reconstruction or augmentation) from 2005 to 2013 were included. "Immediate procedure" cost was computed assuming a 3-day window of care centered on date of surgery. "Total health care utilization" cost was computed using a 9-month window of care (3 months preoperative and 6 months postoperative).

RESULTS

There were 229,446 outpatient arthroscopic ACL reconstructions performed over the 9-year study period. Median immediate procedure cost was $9399.49. Median total health care utilization cost was $13,403.38. Patients who underwent concomitant collateral ligament (medial [MCL], lateral [LCL]) repair or reconstruction had the highest costs for both immediate procedure ($12,473.24) and health care utilization ($17,006.34). For patients who had more than 1 reconstruction captured in the database, total health care utilization costs were higher for the second procedure than the first procedure ($16,238.43 vs $15,000.36), despite the fact that immediate procedure costs were lower for second procedures ($8685.73 vs $9445.26).

CONCLUSION

These results provide a foundation for understanding the public health burden of ACL injuries in the United States. Our findings suggest that further research on the prevention and treatment of ACL injuries is necessary to reduce this burden.

Return to Sport After Primary and Revision Anterior Cruciate Ligament Reconstruction: A Prospective Comparative Study of 552 Patients From the FAST Cohort

BACKGROUND

Few studies have reported the return-to-sport rate at 1-year follow-up after primary and revision anterior cruciate ligament (ACL) reconstruction.

PURPOSE

To compare the return-to-sport rate 1 year after primary and revision ACL reconstruction in the same cohort according to 2 modalities: any kind of sport and the patient's usual sport at the same level as before the injury.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A single-center, prospective cohort study of patients undergoing ACL reconstruction (French prospective Acl STudy [FAST]) was begun in 2012. A comparative study was performed based on a retrospective analysis of data collected prospectively. Included were all athletes aged 18 to 50 years who underwent primary or revision isolated ACL reconstruction between 2012 and 2014. Two groups were formed: primary reconstruction and revision reconstruction. The main criterion was return to sport at 1-year follow-up (yes/no); secondary criteria were return to the usual sport at 1-year follow-up, knee function (International Knee Documentation Committee [IKDC] and Knee injury and Osteoarthritis Outcome Score [KOOS] scores), and psychological readiness (ACL-Return to Sports after Injury [ACL-RSI] score) at 6 months and 1 year.

RESULTS

A total of 552 patients (primary reconstruction group: n = 497, revision reconstruction group: n = 55) were included in the study. There were 373 men and 179 women (mean [±SD] age, 30.2 ± 8.4 years). No significant difference in the return-to-sport rate was found between the 2 groups at 1-year follow-up (primary reconstruction group: 90.9%, revision reconstruction group: 87.3%; P = .38), but patients in the primary reconstruction group resumed their usual sport significantly more often (primary reconstruction group: 63.6%, revision reconstruction group: 49.1%; P = .04). Eight (1.4%) retears occurred during a new sport-related injury within a mean 8.9 ± 2.9 months: 7 (1.4%) in the primary reconstruction group and 1 (1.8%) in the revision reconstruction group ( P = .8). At 1-year follow-up, functional scores were significantly better in the primary reconstruction group for subjective IKDC (82.6 ± 13.3 vs 78.4 ± 16.6; P = .04); KOOS Symptoms/Stiffness (73.3 ± 15.2 vs 67.7 ± 19.6; P = .02), Activities of Daily Living (96.3 ± 6.4 vs 94.3 ± 9.1; P = .04), Sport (79.7 ± 19.1 vs 69.1 ± 24.8; P = .0004), and Quality of Life (69.6 ± 22.7 vs 54.7 ± 24.8; P < .00001) subscales; and ACL-RSI (65 ± 23 vs 49.5 ± 24.8; P < .00001). On multivariate analysis, patients who were more likely to resume their usual sport at 1 year were high-level players (odds ratio [OR], 2.2) who underwent primary reconstruction (OR, 2.0) and had better KOOS Quality of Life (OR, 1.7) and subjective IKDC (OR, 2.1) scores at 6-month follow-up without complications or retears during the first postoperative year (OR, 2.6).

CONCLUSION

At 1-year follow-up, there was no significant difference in the return-to-sport rate between primary and revision ACL reconstruction. Patients who underwent primary reconstruction returned to their usual sport significantly more often.

TRIAL REGISTRATION

NCT02511158 ( ClinicalTrials.gov identifier).

Twenty-Year Outcome of a Longitudinal Prospective Evaluation of Isolated Endoscopic Anterior Cruciate Ligament Reconstruction With Patellar Tendon or Hamstring Autograft

BACKGROUND

Long-term prospective studies of isolated endoscopic anterior cruciate ligament (ACL) reconstruction are limited and may include confounding factors.

PURPOSE

This study aimed to compare the outcomes of isolated ACL reconstruction using the patellar tendon (PT) autograft and the hamstring (HT) autograft in 180 patients over 20 years.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 180 participants undergoing isolated ACL reconstruction between 1993 and 1994 were prospectively recruited. Evaluation was performed at 1, 2, 5, 7, 10, 15, and 20 years after surgery and included the International Knee Documentation Committee (IKDC) knee ligament evaluation with radiographic evaluation, KT-1000 arthrometer side-to-side difference, and subjective scores.

RESULTS

Over 20 years, there were 16 patients (18%) and 9 patients (10%) with an ACL graft rupture in the HT and PT groups, respectively (P = .13). ACL graft rupture was associated with male sex (odds ratio [OR], 3.9; P = .007), nonideal tunnel position (OR, 3.6; P = .019), and age <18 years at the time of surgery (OR, 4.6; P = .003). The odds of a contralateral ACL rupture were increased in patients with the PT graft compared with patients with the HT graft (OR, 2.2; P = .02) and those aged <18 years at the time of surgery (OR, 3.4; P = .001). The mean IKDC scores at 20-year follow-up were 86 and 89 for the PT and HT groups, respectively (P = .18). At 20 years, 53% and 57% of the PT and HT groups participated in strenuous or very strenuous activities (P = .55), kneeling pain was present in 63% and 20% of the PT and HT groups (P = .018), and radiographic osteoarthritic change was found in 61% and 41% of the PT and HT groups (P = .008), respectively.

CONCLUSION

Compared with patients who received the HT graft, patients who received the PT graft had significantly worse outcomes with regard to radiologically detectable osteoarthritis, kneeling pain, and contralateral ACL injury. At 20-year follow-up, both HT and PT autografts continued to provide good subjective outcomes and objective stability. However, further ACL injury is common, particularly in male individuals, younger patients, and those with tunnel malposition.

Defining Thresholds for the Patient Acceptable Symptom State for the IKDC Subjective Knee Form and KOOS for Patients Who Underwent ACL Reconstruction

BACKGROUND

A clinically meaningful change in patient-reported outcome (PRO) may not be associated with an acceptable state that corresponds to "feeling well," also known as the patient acceptable symptom state (PASS). The PASS thresholds for the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) and the Knee injury and Osteoarthritis Outcome Score (KOOS) have not been determined for individuals after anterior cruciate ligament (ACL) reconstruction.

PURPOSE

To determine the PASS thresholds for the IKDC-SKF and KOOS in individuals at 1 to 5 years after ACL reconstruction.

STUDY DESIGN

Cohort study (diagnosis): Level of evidence, 2.

METHODS

Individuals 1 to 5 years after primary ACL reconstruction completed a survey that included the IKDC-SKF and KOOS. All subjects assessed satisfaction with their current state by answering the question, "Taking into account all the activity you have during your daily life, your level of pain, and also your activity limitations and participation restrictions, do you consider the current state of your knee satisfactory?"

RESULTS

A total of 251 participants (mean age ± SD, 26.1 ± 9.9 years) completed the survey at an average of 3.4 ± 1.3 years after ACL reconstruction. Of these, 223 (89.2%) individuals indicated that they were in an acceptable symptom state (PASS-Y). Analysis of the receiver operating characteristic curve revealed that the IKDC-SKF and each of the KOOS subscales (pain, symptoms, activities of daily living [ADL], sport and recreation [sport/rec], and quality of life [QoL]) were significantly better identifiers of PASS than chance as indicated by the significance of the area under the curves. The PASS threshold (sensitivity, specificity) was 75.9 (0.83, 0.96) for the IKDC-SKF, 88.9 (0.82, 0.81) for the KOOS pain, 57.1 (0.78, 0.67) for the KOOS symptoms, 100.0 (0.70, 0.89) for the KOOS ADL, 75.0 (0.87, 0.88) for the KOOS sport/rec, and 62.5 (0.82, 0.85) for the KOOS QoL. In addition, the difference between PASS-Y and PASS-N was statistically significant (P < .001) for all PROs.

CONCLUSION

To our knowledge, this is the first study to identify the PASS thresholds for the IKDC-SKF and the KOOS subscales for individuals 1 to 5 years after ACL reconstruction. By identifying threshold values for the PASS, this study provides additional information to facilitate interpretation of the IKDC-SKF and KOOS in daily practice and clinical research related to ACL reconstruction.

Outcomes in Anterior Cruciate Ligament Reconstruction Surgery

Improving the outcomes in reconstructive surgery of the anterior cruciate ligament (ACL) requires a rigorous and permanent assessment of specific parameters. Therefore, we can increase the degree of reproducibility of the procedure and identify particular aspects in order to achieve an adequate and individualized therapeutic approach for each case. In order to accomplish this goal, the use of complex means (scores) of quantifying results is required. That includes objective means of verifying the parameters in knee surgery, and a subjective evaluation of the patient in order to compare the results.

[The time-related risk for knee osteoarthritis after ACL injury. Results from a systematic review]

AIM

The aim of this review was to evaluate the time-related risk for knee osteoarthritis in patients after ACL injury.

MATERIALS AND METHODS

The primary search was carried out in different medical databases with the deadline 12.01.2014. The search strategy for the evaluation was [ACL] AND [osteoarthritis] including "all fields". All 1656 title/abstracts were reviewed by two independent researchers who selected 140 papers for full text review. Finally, a total of 21 relevant publications were identified for inclusion in this current paper.

RESULTS

The incidence of knee osteoarthritis rises significantly over time. Two years after injury it was 6.9%, after 5 years 32.2%, after 7 years 36.3%, and after 10 years 79.6%. At the same time, the crude relative risk of OA rises as the time interval since injury increases. The relative risk of OA has already doubled by 2 years after ACL injury). By 7 years it has increased fivefold and compared with OA status at the time of injury it is still increasing significantly after 10 years.

CONCLUSIONS

The ACL injury is a significant risk factor for the development of early-onset secondary knee osteoarthritis. Within 5 years of the injury the knee shows clear signs of osteoarthritis on MRI. However, these lesions are often not associated with any clinical signs. Knee osteoarthritis as a severe disease starts 8 years or later after the injury, when it requires treatment.

The Utility of Limb Symmetry Indices in Return-to-Sport Assessment in Patients With Bilateral Anterior Cruciate Ligament Reconstruction

BACKGROUND

The incidence of contralateral anterior cruciate ligament (ACL) injury after ACL reconstruction (ACLR) is high. Often, return-to-sport (RTS) tests of strength and functional hopping rely on limb symmetry indices (LSIs) to identify deficits, although the utility of these measures in athletes with bilateral ACL injuries is unknown.

PURPOSE/HYPOTHESIS

The aim of this study was to investigate if LSIs used as RTS criteria in female patients after unilateral ACLR were appropriate for female patients with bilateral ACL involvement. The hypothesis tested was that asymmetries with traditional LSI measures would be present in a population after unilateral ACLR but would not be present in a population with bilateral ACLR due to the lack of a healthy internal control limb.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 45 female subjects were classified into 3 groups: after second (contralateral) ACLR (ACLR-B; n = 15); after primary unilateral ACLR (ACLR-U; n = 15); and uninjured controls (CTRL; n = 15). After being cleared for RTS, each subject completed a single-legged hop for distance (SLHD), triple hop for distance (THD), and triple-crossover hop for distance (CHD) test, in addition to an isometric quadriceps strength test on both limbs. Means and LSI ([involved limb/uninvolved limb] × 100) were calculated for each test. Limb symmetry deficits were defined by LSI <90%.

RESULTS

Analysis of functional hop testing revealed a side × group interaction for SLHD (P = .001), THD (P = .019), and CHD (P = .04). Side-to-side differences were found in the ACLR-U group for all hop tests (P = .001-.003) and in the ACLR-B group for SLHD (P = .002) and THD tests (P = .024). No side-to side differences were seen in the CTRL group (P > .05). A side × group interaction was found for isometric quadriceps strength (P = .006), with lower LSI seen in the ACLR-U group (81% ± 17.6%) compared with the CTRL group (102.2% ± 10.8%) and the ACLR-B group (95.6% ± 24.9%). Although no interaction was seen, side-to-side differences were noted in the THD in the ACLR-U group (P = .013) and ACLR-B group (P = .024) and in the CHD in the ACLR-U group (P = .001). Despite absence of an LSI deficit, bilateral peak quadriceps strength in the ACLR-B group was comparable to the involved limb of the ACLR-U group and less than in the CTRL group (P = .012).

CONCLUSION

Both the ACLR-U and the ACLR-B groups demonstrated side-to-side deficits during functional hop tests; however, these deficits were not identified according to the clinically accepted LSI values of ≥90%, calling into question the efficacy of current RTS criteria. At the time of RTS, only individuals in the ACLR-U group demonstrated an altered LSI in quadriceps strength. Significantly lower quadriceps strength of both limbs in the ACLR-B group was seen compared with the CTRL group, despite no LSI deficits in quadriceps strength. Current use of LSIs during strength and performance tests may not be an appropriate means of identifying residual deficits in female patients after bilateral ACLR at time of RTS. Furthermore, a better indicator of strength performance in this population may need to include a comparison of strength performance values to the normative values of healthy controls.

Risk of Secondary Injury in Younger Athletes After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis

BACKGROUND

Injury to the ipsilateral graft used for reconstruction of the anterior cruciate ligament (ACL) or a new injury to the contralateral ACL are disastrous outcomes after successful ACL reconstruction (ACLR), rehabilitation, and return to activity. Studies reporting ACL reinjury rates in younger active populations are emerging in the literature, but these data have not yet been comprehensively synthesized.

PURPOSE

To provide a current review of the literature to evaluate age and activity level as the primary risk factors in reinjury after ACLR.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A systematic review of the literature was conducted via searches in PubMed (1966 to July 2015) and EBSCO host (CINAHL, Medline, SPORTDiscus [1987 to July 2015]). After the search and consultation with experts and rating of study quality, 19 articles met inclusion for review and aggregation. Population demographic data and total reinjury (ipsilateral and contralateral) rate data were recorded from each individual study and combined using random-effects meta-analyses. Separate meta-analyses were conducted for the total population data as well as the following subsets: young age, return to sport, and young age + return to sport.

RESULTS

Overall, the total second ACL reinjury rate was 15%, with an ipsilateral reinjury rate of 7% and contralateral injury rate of 8%. The secondary ACL injury rate (ipsilateral + contralateral) for patients younger than 25 years was 21%. The secondary ACL injury rate for athletes who return to a sport was also 20%. Combining these risk factors, athletes younger than 25 years who return to sport have a secondary ACL injury rate of 23%.

CONCLUSION

This systematic review and meta-analysis demonstrates that younger age and a return to high level of activity are salient factors associated with secondary ACL injury. These combined data indicate that nearly 1 in 4 young athletic patients who sustain an ACL injury and return to high-risk sport will go on to sustain another ACL injury at some point in their career, and they will likely sustain it early in the return-to-play period. The high rate of secondary injury in young athletes who return to sport after ACLR equates to a 30 to 40 times greater risk of an ACL injury compared with uninjured adolescents. These data indicate that activity modification, improved rehabilitation and return-to-play guidelines, and the use of integrative neuromuscular training may help athletes more safely reintegrate into sport and reduce second injury in this at-risk population.