Exploring the High Reinjury Rate in Younger Patients Undergoing Anterior Cruciate Ligament Reconstruction

Lateral Extra-Articular Tenodesis and Anterolateral Procedures

The treatment of rotational instability has been an intriguing challenge since the era of modern anterior cruciate ligament (ACL) surgery. Lateral extra-articular procedures (LEAPs) have emerged as a solution to this problem, particularly in high-risk populations. Several studies have shown significant benefits of combining LEAPs with ACL reconstruction, including reduced graft failure rates, improved knee stability, improved rotational stability, and higher return-to-play rates. These findings have led to an in-depth evaluation of LEAPs as lateral extra-articular tenodesis and anterolateral ligament reconstruction and their potential role in improving outcomes after ACL reconstruction.

Avoiding Graft Failure: Lessons Learned from the Stability Trial

The Stability Study was a multicenter, pragmatic, parallel groups, randomized clinical trial comparing hamstring tendon autograft anterior cruciate ligament reconstruction with or without the addition of lateral extra-articular tenodesis in young patients at high risk of graft failure. Having recruited 618 patients with a 5% loss to follow up, we were able to demonstrate a clinically and statistically significant reduction in clinical failure and graft rupture at 2 years postoperative. No differences in patient-reported outcomes (PROs) were demonstrated between groups; however, patients who experienced an adverse event had significantly worse PROs than those who did not.

A comparative study on 3D printing-assisted arthroscopic IDEAL point femoral tunnel positioning for anterior cruciate ligament reconstruction versus conventional arthroscopic positioning

BACKGROUND

This study aimed to investigate the feasibility and precision of using a 3D-printed template for femoral tunnel placement in guiding the optimal positioning of the Internal anatomical stop and Low tension maintenance (IDEAL) bone tunnel during single-bundle anterior cruciate ligament (ACL) reconstruction.

METHODS

A retrospective analysis was conducted on 40 patients who underwent arthroscopic single-bundle ACL reconstruction at our hospital between April 2021 and November 2021. In the direct vision group, the IDEAL bone tunnel was positioned using radiofrequency localization directly visualized at the stump. In the 3D-printed positioning group, preoperative CT scans and Digital Imaging and Communications in Medicine (DICOM) data were employed. Following the Quadrant method by Bernard, the femoral tunnel's depth was set at 25% and its height at 29%. Postoperative plain CT scans enabled the reconstruction of 3D models for both groups. The accuracy of femoral tunnel placement was then compared.

RESULTS

The central locations of the bone tunnels in the direct vision group were at a mean depth of 25.74 ± 1.84% and a height of 29.22 ± 2.97%. In the 3D printing localization group, these values were 25.39 ± 2.98% for depth and 28.89 ± 2.50% for height, respectively. No significant differences were found in tunnel positioning between the groups. Both groups demonstrated statistically significant improvements in International Knee Documentation Committee Subjective Knee Form (IKDC) and Lysholm scores postoperatively, with no significant differences observed 12 months post-surgery.

CONCLUSION

The findings of this study suggest that 3D printing-assisted arthroscopic IDEAL point femoral tunnel positioning and conventional arthroscopic positioning are feasible and effective for ACL reconstruction. Using 3D printing technology to design femoral anchor points in ACL reconstruction allows for the customization of anterior fork reconstruction and precise bone tunnel positioning, supporting the goal of individualized and accurate reconstruction.

Return to Soccer After Acute Anterior Cruciate Ligament Primary Repair: A 2-Year Minimum Follow-up Study of 50 Amateur Players

BACKGROUND

Return to sport (RTS) after treatment of an anterior cruciate ligament (ACL) tear is a critical parameter to assess the outcome of a surgical procedure. However, few studies have investigated RTS after ACL repair.

PURPOSE

To evaluate RTS of a group of amateur soccer players at a minimum follow-up of 2 years after ACL repair.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A retrospective review of all patients treated with acute ACL repair was conducted. A total of 50 amateur soccer players were included in the study. Patients were examined clinically or contacted to complete postoperative patient-reported outcome measures, namely the Knee injury and Osteoarthritis Outcome Score, the International Knee Documentation Committee questionnaire, the ACL-Return to Sport After Injury scale, and the Forgotten Joint Score-12.

RESULTS

The patients' mean age was 25.8 ± 7.7 years (range, 14-47 years), and the mean follow-up was 34.3 ± 10.7 months (range, 24-51.3 months). The median Tegner Activity Scale score was 9. The ACL repair failure rate was 16% (8/50). The mean time from repair to failure was 23.1 ± 12.7 months (range, 6-44 months), and the mean age of patients who sustained ACL repair failure was 19.9 ± 3.3 years (range, 14-24 years), significantly lower compared with patients who did not experience ACL repair failure (26.9 ± 7.9 years; range, 16-47 years; P = .017). Multivariate analysis showed that age ≤21 years was the only significant risk factor for ACL repair failure (odds ratio, 5.45; confidence interval, 1.24-27.91; P = .041). Excluding the 8 patients who experienced repair failure, 31 of 42 patients (73.8%) returned to soccer after ACL repair, with 29 of the 31 (93.5%) returning at their preinjury level of play. Moreover, patients who played competitive soccer and returned to their preinjury level of play were significantly younger than those who did not return to their preinjury level of play (mean, 21.1 ± 3.4 vs 29.2 ± 9.5 years, respectively; P = .002) and had significantly better ACL-Return to Sport After Injury scores (mean, 96.6 ± 4 vs 87.8 ± 11, respectively; P = .044).

CONCLUSION

In this study, 73.8% (n = 31) of patients returned to playing soccer, of whom 93.5% (n = 29) returned to their preinjury level after ACL repair. The failure rate was 16% (n = 8) and mainly involved patients ≤21 years old.

A Recess Is Observed Between the Posterior Knee Capsule and the Meniscotibial Ligament Complex in Pediatric Specimens

Purpose

To define the surgical anatomy of the meniscotibial ligament complex of the pediatric medial and lateral menisci and their relation to the proximal tibial physis and posterior joint capsule.

Methods

Fourteen pediatric cadaveric knee specimens (aged 3 months to 11 years) were dissected to clarify the relation of the posterior knee capsule, the meniscus, and the meniscotibial ligament complex. Metallic markers were placed marking the meniscotibial ligament capsular attachment on the proximal tibia. Specimens underwent computed tomography scanning to evaluate pin placement and relation to the physis. A digital measurement tool was used to measure the distances between the proximal tibial physis and the pins (placed at 5 points on both the lateral and medial menisci).

Results

In each specimen, clear separation was noted between the posterior joint capsule from the meniscus and meniscotibial ligament complex in the medial and lateral compartments. There was an increase in the distance between the proximal tibial physis and the insertion points of the meniscotibial ligament complex with increasing specimen age. For both the medical and lateral menisci in group 1, the median meniscotibial ligament insertion points were often less than 7 mm (interquartile range, 0.00-7.8 mm) away from the physis. The median meniscotibial ligament insertion points in group 2 tended to be farther from the physis but always less than 20 mm (interquartile range, 2.5-17.5 mm)-and as close as less than 5 mm (lateral posterior root).

Conclusions

In this anatomic study of pediatric knees, we observed a distinct recess/cul-de-sac space between the posterior knee capsule and meniscal attachments in all specimens. This defines a distinct plane between the posterior knee capsule and the meniscotibial ligament complex, with a distance between the physis and meniscotibial ligament capsular attachments that increases with age.

Clinical Relevance

The anatomic parameters evaluated in our study should be considered as future meniscal repair and transplantation techniques aim to restore the meniscal anatomy, stability, and mobility provided by the meniscotibial ligament complex and capsule structures.

Lower anxiety level to perform movements after revision anterior cruciate ligament reconstruction with lateral extra-articular tenodesis compared to without lateral extra-articular tenodesis

PURPOSE

To evaluate the anxiety level to perform movements in patients after revision anterior cruciate ligament reconstruction (ACLR) combined with lateral extra-articular tenodesis (LET) compared to patients after revision ACLR without LET.

METHODS

Ninety patients who underwent revision ACLR with ipsilateral bone-patellar tendon-bone autograft and with a minimum of 12 months follow-up were included in this study. Patients were divided into two groups: patients who received revision ACLR in combination with LET (revision ACLR_LET group; mean follow-up: 29.4 months, range: 12-80 months), and patients who received revision ACLR without LET (revision ACLR group; mean follow-up: 61.1 months, range: 22-192 months). All patients filled in a questionnaire about anxiety level related to physical activity and sports, the Knee injury and Osteoarthritis Outcome Score (KOOS), the International Knee Documentation Committee subjective form (IKDCsubjective), and the Tegner Activity Score.

RESULTS

Patients in the revision ACLR_LET group had a significantly lower anxiety level to perform movements than patients in the revision ACLR group (p < 0.05). No significant differences were found in KOOS, IKDCsubjective, and Tegner Activity Scores.

CONCLUSIONS

Patients who received LET in addition to revision ACLR have a lower anxiety level to perform movements than patients with revision ACLR alone, despite non-different subjective functional outcomes.

STUDY DESIGN

Retrospective cohort study, Level of evidence: III.

Reduction in re-rupture rates following implementation of return-to-sport testing after anterior cruciate ligament reconstruction in 313 patients with a mean follow-up of 50 months

OBJECTIVES

The objective of this study was to assess the mid-term effectiveness of a return to sport (RTS) test in relation to preventing anterior cruciate ligament (ACL) re-rupture and contralateral ACL injury following ACL reconstruction (ACLR). Furthermore, this study aimed to assess the timing of passing a, RTS-test after surgery, and the effect age has on RTS outcomes.

METHODS

Patients undergoing ACLR between August 2014 and December 2018 took an RTS-test following rehabilitation. The RTS-test consisted of the Anterior Cruciate Ligament Return to Sport After Injury Scale, a single-leg hop, a single-leg triple hop, a single-leg triple cross-over hop, a box-drop vertical jump down, a single-leg 4-rep max-incline leg press, and a modified agility T test. RTS-passing criteria were ≥90% limb symmetry index in addition to defined takeoff and landing parameters. Mid-term review assessed sporting level, ACL re-injury, and contralateral ACL injury.

RESULTS

A total of 352 patients underwent RTS-testing, following ACLR with 313 (89%) contactable at follow-up, a mean of 50 months (standard deviation: 11.41, range: 28-76) after surgery. The re-rupture rate was 6.6% after passing the RTS-test and 10.3% following failure (p ​= ​0.24), representing a 36% reduction. Contralateral ACL injury rate after surgery was 6% and was 19% lower in those passing the RTS test. The mean age of patients passing their first RTS-test was significantly higher than that of those who failed (p ​= ​0.0027). Re-ruptures in those who passed the RTS test first time occurred late (>34 months), compared to those who failed first time, which all occurred early (<33 months) (p ​= ​0.0015). The mean age of re-rupture was significantly less than those who did not sustain a re-rupture (p ​= ​0.025).

CONCLUSION

Passing a RTS-test following ACLR reduces ACL re-rupture by 36.21% and contralateral ACL injury by 19.15% at mid-term follow-up. Younger patients are more likely to fail a RTS-test and are at higher risk of contralateral ACL rupture.

LEVEL III EVIDENCE

Trends in Pediatric Anterior Cruciate Ligament Reconstruction in Australia: An Analysis of Australian Medicare Benefits Schedule Database From 2001 to 2020

BACKGROUND

Anterior cruciate ligament (ACL) injuries are common and increasingly prevalent in the pediatric population. However, there remain sparse epidemiological data on the surgical treatment of these injuries. The objective of this study is to assess the trends in the rate of pediatric ACL reconstruction in Australia over the past 2 decades.

METHODS

The incidence of ACL reconstruction from 2001 to 2020 in patients 5 to 14 years of age was analyzed using the Australian Medicare Benefits Schedule (MBS) database. Data were stratified by sex and year. An offset term was introduced using population data from the Australian Bureau of Statistics to account for population changes over the study period.

RESULTS

A total of 3719 reconstructions for the management of pediatric ACL injuries were performed in Australia under the MBS in the 20-year period from 2001 to 2020. There was a statistically significant annual increase in the total volume and per capita volume of pediatric ACL reconstructions performed across the study period ( P <0.0001). There was a significant increase in the rate of both male and female reconstructions ( P <0.0001), with a greater proportion of reconstructions performed on males (n=2073, 56%) than females (n=1646, 44%). In 2020, the rate of pediatric ACL reconstructions decreased to a level last seen in 2015, likely due to the effects of COVID-19.

CONCLUSIONS

The incidence of ACL reconstruction in skeletally immature patients has increased in Australia over the 20-year study period. This increase is in keeping with evidence suggesting poor outcomes with nonoperative or delayed operative management.

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.

Tracking and predicting the treatment adherence of patients under rehabilitation: a three-wave longitudinal validation study for the Rehabilitation Adherence Inventory

This study aimed to develop and validate a new measurement tool, the Rehabilitation Adherence Inventory (RAI), to measure patients' rehabilitation adherence. We recruited 236 patients with anterior cruciate ligament (ACL) ruptures from the United Kingdom (Mage = 33.58 ± 10.03, range = 18 to 59; female = 46.2%). Participants completed a survey, that measured their rehabilitation adherence, rehabilitation volume, psychological needs support, autonomous motivation, and intention at baseline, and at the 2nd and 4th month. Factorial, convergent, discriminant, concurrent, predictive, ecological validity and test-retest reliability of the RAI were tested via exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and structural equation modelling (SEM). All the EFAs, CFAs, and SEMs yielded acceptable to excellent goodness-of-fit, χ2 = 10.51 to 224.12, df = 9 to 161, CFI > 0.95, TLI > 0.95, RMSEA <0.09 [90%C I < 0.06 to 0.12], SRMR <0.04. Results fully supported the RAI's factorial, convergent, discriminant, and ecological validity, and test-retest reliability. The concurrent and predictive validity of the RAI was only partially supported because the RAI scores at baseline was positively associated with rehabilitation frequency at all time points (r = 0.34 to 0.38, p < 0.001), but its corresponding associations with rehabilitation duration were not statistically significant (p = 0.07 to 0.93). Overall, our findings suggest that this six-item RAI is a reliable and valid tool for evaluating patients' rehabilitation adherence.

Evaluation of Failed ACL Reconstruction: An Updated Review

Failure rates among primary Anterior Cruciate Ligament Reconstruction (ACLR) range from 3.2% to 11.1%. Recently, there has been increased focus on surgical and anatomic considerations which predispose patients to failure, including excessive posterior tibial slope (PTS), unaddressed high-grade pivot shift, and improper tunnel placement. The purpose of this review was to provide a current summary and analysis of the literature regarding patient-related and technical factors surrounding revision ACLR, rehabilitation considerations, overall outcomes and return to sport (RTS) for patients who undergo revision ACLR. There is a convincingly higher re-tear and revision rate in patients who undergo ACLR with allograft than autograft, especially amongst the young, athletic population. Unrecognized Posterior Cruciate Ligament (PLC) injury is a common cause of ACLR failure and current literature suggests concurrent operative management of high-grade PLC injuries. Given the high rates of revision surgery in young active patients who return to pivoting sports, the authors recommend strong consideration of a combined ACLR + Anterolateral Ligament (ALL) or Lateral extra-articular tenodesis (LET) procedure in this population. Excessive PTS has been identified as an independent risk factor for ACL graft failure. Careful consideration of patient-specific factors such as age and activity level may influence the success of ACL reconstruction. Additional technical considerations including graft choice and fixation method, tunnel position, evaluation of concomitant posterolateral corner and high-grade pivot shift injuries, and the role of excessive posterior tibial slope may play a significant role in preventing failure.

Anterior cruciate ligament: A brief narrative review of main risk factors for injury and re-injury

Anterior cruciate ligament (ACL) injury is one of the main injuries in professional and amateur athletes of different sports. Hundreds of thousands of ACL ruptures occurs annually, and only 55% of the athletes return to competitive level, with a 15 times higher chance of suffering a second injury. 60% of these injuries occur without physical contact and since they occur in the acute process, they can cause joint effusion, muscle weakness and functional incapacity. In the long term, they can contribute to a premature process of osteoarthritis. This narrative review is of particular interest for clinicians, practitioners, coaches and athletes to understand the main factors that contribute to an injury and/or re-injury and thus, to optimize their training to reduce and/or prevent the risk of injury and/or reinjury of ACL. Therefore, we aimed reports a narrative overview of the literature surrounding communication and explore through a theoretical review, the main risk factors for an ACL injury and/or re-injury, as well as bringing practical and correct methods of training applications. The lack of theoretical/practical knowledge on the part of rehabilitation and/or training professionals may impair the treatment of an athlete and/or student. High-quality research that can testing different training methods approaches in randomized controlled trials is needed.

Primary Anterior Cruciate Ligament Reconstruction with Suture Tape Augmentation: A Case Series of 252 Patients

Anterior cruciate ligament reconstruction (ACLR) using suture tape augmentation to internally brace is a relatively new technique. The primary goal of this study was to prospectively collect patient-reported outcomes (PROs) and surgical history from patients who underwent primary ACLR with internal bracing to determine if internal bracing resulted in a low graft failure rate while maintaining acceptable PROs. A total of 252 patients with a mean age of 23.6 years (95% confidence interval [CI]: 22.1-25.1) and a mean follow-up of 37.9 months (95% CI: 35.8-40.0) were included in this study. Patients who underwent primary ACLR with internal brace augmentation between July 12, 2016 and July 31, 2021 were eligible. A total of 222 patients were contacted via telephone and administered the visual analog scale (VAS), the single assessment numeric evaluation (SANE), the Lysholm knee score scale, and, if applicable, the short version ACL return to sport after injury (SV-ACL-RSI) survey. Additionally, patients were asked to give an updated orthopaedic history. Thirty additional patients were included from either our institution's registry or by completing their surveys in-office or by e-mail. The minimal clinically important difference (MCID) and patient-acceptable symptom states (PASS) were calculated based on our patient population and applied to each individual patient. The patients' electronic health record (EHR) was searched for pre- and postoperative clinical data including KT-1000 arthrometer measurements. Two patients (0.8%) had subsequent graft failures and one patient (0.4%) required a revision surgery. MCID was achieved in 242 patients (96.0%) for the Lysholm, 227 patients (90.1%) for the SANE, and 146 patients (57.9%) for the VAS. PASS was achieved in 214 patients (84.9%) for the Lysholm, 198 patients (78.6%) for the SANE, and 199 (80.0%) patients for the VAS, postoperatively. Of note, 65 patients (25.8%) exceeded the PASS threshold for the VAS preoperatively. A total of 127 patients (84.4%) met the cutoff of ≥60/100 for the SV-ACL-RSI survey postoperatively. Postoperative KT-1000 measurements showed near-identical side-to-side differences at both the 13.6-kg pull and manual maximum pull. When stratifying patients based on age at the time of surgery, it was noted that patients younger than 25 years had significantly higher SANE scores (91.6 [95% CI: 90.2-92.9] vs. 82.6 [95% CI: 79.0-86.2]; p < 0.0001) and lower VAS pain scores (0.7 [95% CI: 0.5-0.8] vs. 1.2 [95% CI: 0.8-1.5]; p = 0.004). Primary ACLR with internal bracing led to acceptable patient outcomes and a graft failure rate of less than 1%. LEVEL OF EVIDENCE:: case series, IV.

The relationship between lateral femoral condyle ratio measured by MRI and anterior cruciate ligament injury

Background

Previous studies have shown that the lateral femoral condyle ratio (LFCR) measured by X-ray has a significant relationship with the anterior cruciate ligament (ACL) injury. However, few relevant studies have been performed on LFCR measured by magnetic resonance imaging (MRI).

Purpose

(1) To evaluate the relationship between LFCR measured by MRI and ACL injury or rerupture. (2) To compare the LFCR measured by MRI with existing bony morphological risk factors and screen out the most predictive risk factors for primary ACL injury or rerupture.

Study Design

Cohort study; Level of evidence, 3.

Methods

Totally 147 patients who underwent knee arthroscopic surgery from 2015 to 2019 with minimum follow-up of 48 months were retrospectively evaluated. Patients were placed into three groups: 1) the control group of patients with simple meniscus tears without ligament injury; 2) the primary noncontact ACL injury group; 3) ACL rerupture group (ACL reconstruction failure). The LFCR measured by MRI and other previous known risk factors associated with MRI (notch width index, medial tibial slope, lateral tibial slope, medial tibial depth, lateral tibial height) were performed to evaluate their predictive value for ACL injury and rerupture. All the risk factors with p < 0.01 according to univariate analysis were included in the logistic regression models. Receiver operating characteristic (ROC) curves were analyzed for sensitivity, specificity, cut-off, and area under the curve (AUC). Z tests were used to compare the AUC values.

Results

The LFCR measured by MRI was obviously higher in primary ACL injury group (0.628 ± 0.020) and in ACL rerupture group (0.625 ± 0.021) than that in the control group (0.593 ± 0.030). The best risk factor was the LFCR with a cut-off of 0.602 (AUC, 0.818; 95% CI, 0.748-0.878; sensitivity, 90%; specificity, 66%). When combined with lateral tibial slope (cutoff, 7°) and lateral tibial height (cutoff, 3.6 mm), the diagnostic performance was improved significantly (AUC, 0.896; 95% CI, 0.890-0.950; sensitivity, 87%; specificity, 80%).

Conclusion

The increased LFCR measured by MRI was associated with a significantly higher risk for ACL injury or rerupture. The combination of LFCR, lateral tibial slope and lateral tibial height were the most predictive risk factors. This may help clinicians identify susceptible individuals and allow precision approaches for better prevention, treatment and management of this disease.

Global knee function rating more strongly influences adolescent athletes that sustain a sports-related surgical ACL re-injury or contralateral ACL injury

PURPOSE

This study evaluated differences between adolescent athletes who sustained a surgical anterior cruciate ligament (ACL) re-injury, or contralateral ACL injury following return to sports bridge programme participation (Group 1) compared to those that did not (Group 2).

METHODS

At 19.9 ± 7 years of age, 198 athletes participated in this study. Groups were compared for time postsurgery, preprogramme and postprogramme Knee Outcome Survey Sports Activity Scale (KOS-SAS) and global rating of knee function (GRKF) during sports activities, postprogramme lower extremity physical function test performance and perceived sports performance compared to preinjury level.

RESULTS

By 6.0 ± 3.2 years postsurgery, 11 (5.6%) sustained another ACL injury. Group 1 was younger (17.3 ± 1.7 years vs. 20.1 ± 6.8 years, p < 0.001). Postprogramme re-evaluation revealed that Group 1 had a greater GRKF compared to their programme initiation GRKF than Group 2 (32.6 ± 38 vs. 20.0 ± 23, p = 0.04). Group 1 also had a greater mean preprogramme to postprogramme GRKF change than Group 2 (51.3 ± 31 vs. 35.5 ± 21, p = 0.02) (effect size = 0.73). More Group 1 subjects also had a GRKF difference that exceeded the overall mean than Group 2 (p = 0.04). Group 1 had moderately strong relationships between preprogramme and postprogramme GRKF score change and the postprogramme GRKF score (r = 0.65, p = 0.04) and between preprogramme and postprogramme KOS-SAS score change and postprogramme GRKF score (r = 0.60, p = 0.04).

CONCLUSION

Global rating scores had a stronger influence among adolescent athletes that sustained either surgical ACL re-injury or contralateral ACL injury. Since group physical function and neuromuscular control factors were similar, clinicians need to increase their awareness and understanding of other factors that may influence surgical ACL re-injury or contralateral ACL injury risk.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Why Your Patient May Need an ACL Reconstruction Plus Lateral Extra-Articular Tenodesis Procedure

Anterior cruciate ligament (ACL) tears are one of the most common knee injuries experienced by active individuals engaging in cutting sports. Despite improved surgical techniques and rehabilitation, the return to sport rate and re-tear rates remain unsatisfactory. Lateral extra-articular tenodesis (LET) is a procedure that has been growing in interest when performed in conjunction with ACL reconstruction. The benefits of adding an LET procedure to an ACL surgery may include greater rotational stability, decreased re-tear rates, and improved return to play. Level of evidence: V.

Unsupervised Machine Learning of the Combined Danish and Norwegian Knee Ligament Registers: Identification of 5 Distinct Patient Groups With Differing ACL Revision Rates

BACKGROUND

Most clinical machine learning applications use a supervised learning approach using labeled variables. In contrast, unsupervised learning enables pattern detection without a prespecified outcome.

PURPOSE/HYPOTHESIS

The purpose of this study was to apply unsupervised learning to the combined Danish and Norwegian knee ligament register (KLR) with the goal of detecting distinct subgroups. It was hypothesized that resulting groups would have differing rates of subsequent anterior cruciate ligament reconstruction (ACLR) revision.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

K-prototypes clustering was performed on the complete case KLR data. After performing the unsupervised learning analysis, the authors defined clinically relevant characteristics of each cluster using variable summaries, surgeons' domain knowledge, and Shapley Additive exPlanations analysis.

RESULTS

Five clusters were identified. Cluster 1 (revision rate, 9.9%) patients were young (mean age, 22 years; SD, 6 years), received hamstring tendon (HT) autograft (91%), and had lower baseline Knee injury and Osteoarthritis Outcome Score (KOOS) Sport and Recreation (Sports) scores (mean, 25.0; SD, 15.6). Cluster 2 (revision rate, 6.9%) patients received HT autograft (89%) and had higher baseline KOOS Sports scores (mean, 67.2; SD, 16.5). Cluster 3 (revision rate, 4.7%) patients received bone-patellar tendon-bone (BPTB) or quadriceps tendon (QT) autograft (94%) and had higher baseline KOOS Sports scores (mean, 65.8; SD, 16.4). Cluster 4 (revision rate, 4.1%) patients received BPTB or QT autograft (88%) and had low baseline KOOS Sports scores (mean, 20.5; SD, 14.0). Cluster 5 (revision rate, 3.1%) patients were older (mean age, 42 years; SD, 7 years), received HT autograft (89%), and had low baseline KOOS Sports scores (mean, 23.4; SD, 17.6).

CONCLUSION

Unsupervised learning identified 5 distinct KLR patient subgroups and each grouping was associated with a unique ACLR revision rate. Patients can be approximately classified into 1 of the 5 clusters based on only 3 variables: age, graft choice (HT, BPTB, or QT autograft), and preoperative KOOS Sports subscale score. If externally validated, the resulting groupings may enable quick risk stratification for future patients undergoing ACLR in the clinical setting. Patients in cluster 1 are considered high risk (9.9%), cluster 2 patients medium risk (6.9%), and patients in clusters 3 to 5 low risk (3.1%-4.7%) for revision ACLR.

A lateral extra-articular tenodesis without additional hardware: Surgical technique and biomechanical comparison with an anatomic anterolateral ligament reconstruction in the augmentation of anterior cruciate ligament reconstruction

BACKGROUND

The aims of this study were to describe a lateral extra-articular tenodesis (LET) using no additional hardware and compare the tibiofemoral kinematics of anterior cruciate ligament (ACL) reconstruction augmented with either the LET or a standard anatomic anterolateral ligament (ALL) reconstruction using intra-tunnel fixation.

METHODS

Ten cadaveric knees were mounted on a robotic testing system and underwent a kinematic assessment of anterior tibial translation and internal tibial rotation under a simulated pivot-shift in the following states: ACL-intact, ACL-sectioned, ACL-sectioned/anterolateral complex (ALC)-sectioned, ACL-reconstructed/ALC-sectioned, ACL-reconstructed/ALL-reconstructed, and ACL-reconstructed/LET. For the LET, an iliotibial autograft was passed under the fibular collateral ligament and secured to the femur with the pull sutures of the ACL reconstruction femoral cortical suspensory fixation device, positioned at the distal ridge of Kaplan's fibers.

RESULTS

Anterior tibial translation was restored to normal by ACL reconstruction without meaningful benefit of augmentation with LET or ALL. ACL reconstruction restored internal tibial rotation close to normal between 0° and 30°, but increased internal tibial rotation persisted between 45° and 90°. Augmentation of ACL reconstruction with the LET reduced internal rotation close to normal between 45° and 90°, whereas increased internal rotation persisted after ALL reconstruction.

CONCLUSION

ACL reconstruction and LET are complementary in controlling tibiofemoral kinematics of knees with a combined ACL and ALC injury: ACL reconstruction restored native tibiofemoral kinematics except for internal rotation at flexion greater than 30°. The increased internal rotation at flexion greater than 30° was restored to normal with an LET, but not with an ALL reconstruction.

Does core stability training improve hopping performance and kinetic asymmetries during single-leg landing in anterior cruciate ligament reconstructed patients?

Safe return to sport (RTS) after anterior cruciate ligament reconstruction (ACLR) surgery is important. Core stabilization is common within rehabilitation, but its influence on hopping performance and single-leg landing kinetics among athletes post-ACLR is unclear. Twenty-four male professional athletes who had ACL reconstruction surgery (time since surgery = 11.47 ± 1.55 months) were recruited and randomly assigned to exercise (n = 12) and control (n = 12) groups. Exercise group received an 8-week core stability exercise program. Limb symmetry index (LSI) for single-leg hop for distance (SLH) and triple hop (TRH) tests, and single-leg landing kinetics (multidirectional ground reaction forces) were measured pre- and post-intervention. In post-test, the participants in exercise group were more symmetrical in SLH (P = .04, CI = 0.01-7.68) and TRH (P = .01, CI = 0.28-11.1) distances. They also improved their LSI values for vertical ground reaction force (vGRF), though not significantly (P < .05). LSI for anteroposterior (a-p) and mediolateral (m-l) GRFs remained unchanged for participants of both groups. Our findings indicate the positive effect of core exercise on decreasing between-limb asymmetries during SLH and TRH tests. Our results demonstrate that despite lack of change in kinetics, functional performance is more symmetrical following core stability training.

Impact of Lateral Extra-Articular Procedure Augmentation on Rerupture Risk and Tegner Activity Scale Outcomes in Adolescent Anterior Cruciate Ligament: A Matched Comparative Study With a Minimum 2-Year Follow-up

BACKGROUND

Despite the well-established role of lateral extra-articular procedures (LEAPs) in reducing failure rates after anterior cruciate ligament (ACL) reconstruction (ACLR) in the adult population, similar in-depth research for the adolescent and pediatric population remains lacking.

PURPOSE

To examine the effect of the LEAP augmentation on the rerupture rate after ACLR in patients aged <18 years.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This was a retrospective analysis of prospectively collected data from October 2012 to June 2020, involving adolescents <18 years old undergoing primary ACLR with a minimum follow-up of 2 years. Two groups, matched for age, sex, Tegner activity scale, and presence of meniscal injury, were established: ACLR alone and ACLR+LEAP augmentation. The primary outcome measure was the rate of rerupture after ACLR. The secondary outcome measures were the rate of non-graft rupture related reoperation after ACLR; rate of return to sport (RTS) rate, timing, and level compared with preinjury status; and functional scores including the International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS) (Pain, Symptoms, Activities of Daily Living, Sport and Recreation, and Quality of Life), Tegner activity scale score, ACL Return to Sport after Injury (ACL-RSI) score, and Lysholm score.

RESULTS

After accounting for follow-up losses, we analyzed 132 patients who underwent ACLR alone and 121 patients who underwent ACLR+LEAP from the initial 147 per group. The mean age of the patients in both groups was 16.1 years (SD, 1.1 and 1.0 years, respectively), with similar patient and injury characteristics across both groups (P > .05). Both groups also showed comparable preoperative functional scores. A significantly lower preoperative ACL-RSI score was observed in the ACLR-alone group compared with the ACLR+LEAP group (P = .0044). Graft rupture was significantly less common in the ACLR+LEAP group (2.5%) than in the ACLR-alone group (13.6%) (P = .002). The attributable risk reduction for ACLR+LEAP was 11.1%, and the calculated number needed to treat was 9. Kaplan-Meier analysis showed significantly better rerupture-free survival at 5 years for the ACLR+LEAP group (P = .001). Cox regression confirmed a 6-fold increased rerupture risk in the ACLR-alone group (P = .004). At the final follow-up, despite similar IKDC, KOOS, Lysholm, and ACL-RSI values across both groups, the ACLR+LEAP group had a significantly higher Tegner score (7.2 vs 6.3; P = .0042). No significant differences were observed in RTS rates or sport level compared with preinjury states between the groups.

CONCLUSION

ACLR+LEAP augmentation significantly reduced rerupture risk and facilitated higher postoperative activity levels in adolescents.

REGISTRATION

NCT02511158 (ClinicalTrials.gov identifier).

Limb asymmetries persist 6 months after anterior cruciate ligament reconstruction according to the results of a jump test battery

Objectives

Test batteries used to assess a patient's return-to-sports (RTS) following anterior cruciate ligament reconstruction (ACLR) are currently undergoing continual development, although no consensus exist on tests to be administered to athletes before allowing return to play. A simple standardized jump test battery was developed to objectively evaluate knee function following ACLR, thereby aiding in RTS decision-making.

Methods

Thirty-three patients who underwent ACLR were prospectively assessed pre-operatively, 6, and 12 months after surgery. Knee function was assessed using a device for optical detection using a test battery consisting of three jump tests: monopodalic countermovement jump (CMJ), drop jump, and monopodalic side-hop. Limb symmetry index (LSI) was reported for all tests at all time points. LSI ≥90% was defined as RTS criteria.

Results

At 12-month evaluation, mean LSI significantly improved compared to 6-month follow up (p < 0.01), and also compared to baseline (p < 0.01), reporting a mean value of 92.6% for CMJ, 90.6 for drop jump and 96.9% for side hop test. Most patients fulfilled the RTS criteria 12 months after surgery (LSI ≥90%). The percentages of patients demonstrating LSI ≥90% at 6 months was 7/33 (21.2%) for CMJ, 12/33 (36.4%) for drop jump, and 11/33 (33.3%) for side-hop test. One year after surgery, percentages grew up to 66.6% (22/33), 63.6% (21/33), and 81.8% (27/33) respectively.

Conclusion

Six months after ACLR, knee functional performance was unsatisfactory in most patients, whereas a significantly higher percentage of patients met RTS criteria 1 year after surgery. The results of the jump test battery proposed in this study support the idea that timing for resumption of cutting and pivoting sports should be delayed later than 6 months, as still limb asymmetries persist at this time point.

External validation of the Norwegian anterior cruciate ligament reconstruction revision prediction model using patients from the STABILITY 1 Trial

PURPOSE

A machine learning-based anterior cruciate ligament (ACL) revision prediction model has been developed using Norwegian Knee Ligament Register (NKLR) data, but lacks external validation outside Scandinavia. This study aimed to assess the external validity of the NKLR model (https://swastvedt.shinyapps.io/calculator_rev/) using the STABILITY 1 randomized clinical trial (RCT) data set. The hypothesis was that model performance would be similar.

METHODS

The NKLR Cox Lasso model was selected for external validation owing to its superior performance in the original study. STABILITY 1 patients with all five predictors required by the Cox Lasso model were included. The STABILITY 1 RCT was a prospective study which randomized patients to receive either a hamstring tendon autograft (HT) alone or HT plus a lateral extra-articular tenodesis (LET). Since all patients in the STABILITY 1 trial received HT ± LET, three configurations were tested: 1: all patients coded as HT, 2: HT + LET group coded as bone-patellar tendon-bone (BPTB) autograft, 3: HT + LET group coded as unknown/other graft choice. Model performance was assessed via concordance and calibration.

RESULTS

In total, 591/618 (95.6%) STABILITY 1 patients were eligible for inclusion, with 39 undergoing revisions within 2 years (6.6%). Model performance was best when patients receiving HT + LET were coded as BPTB. Concordance was similar to the original NKLR prediction model for 1- and 2-year revision prediction (STABILITY: 0.71; NKLR: 0.68-0.69). Concordance 95% confidence interval (CI) ranged from 0.63 to 0.79. The model was well calibrated for 1-year prediction while the 2-year prediction demonstrated evidence of miscalibration.

CONCLUSION

When patients in STABILITY 1 who received HT + LET were coded as BPTB in the NKLR prediction model, concordance was similar to the index study. However, due to a wide 95% CI, the true performance of the prediction model with this Canadian and European cohort is unclear and a larger data set is required to definitively determine the external validity. Further, better calibration for 1-year predictions aligns with general prediction modelling challenges over longer periods. While not a large enough sample size to elicit the true accuracy and external validity of the prediction model when applied to North American patients, this analysis provides more support for the notion that HT plus LET performs similarly to BPTB reconstruction. In addition, despite the wide confidence interval, this study suggests optimism regarding the accuracy of the model when applied outside of Scandinavia.

LEVEL OF EVIDENCE

Level 3, cohort study.

Anterior Cruciate Ligament-Return to Sport after Injury (ACL-RSI) subcategories are affected by subjective running ability and medial single-leg hop distance in postreconstruction patients at 6 months

Purpose

This study aimed to investigate the intricate relationship between physical function factors and each subcategory score of the Anterior Cruciate Ligament-Return to Sport after Injury (ACL-RSI) scale among patients following ACL reconstruction.

Methods

Participants comprised 59 patients who had undergone primary ACL reconstruction using hamstring tendon. The ACL-RSI was completed 6 months after reconstruction and five physical functions were measured in patients on the same day. Simple linear regression was performed multiple times to investigate the relationship between ACL-RSI subcategory scores as a dependent variable and each independent variable (knee strength, leg anterior reach distance, single-leg hop [SLH] distances, side bridge endurance, and subjective running ability). Multiple regression analysis was performed using a stepwise method, with factors showing a risk rate <0.05 in simple linear regression analyses as independent variables and the ACL-RSI in each subcategory score as the dependent variable.

Results

Multiple regression analysis showed that subjective running ability affected all subcategories (p ≤ 0.001), and that the limb symmetry index of medial SLH distance affected both the Emotions (p = 0.047) and Confidence (p = 0.009) subcategories. Higher subjective running ability and greater limb symmetry in the medial SLH were thus positively associated with each dimension of psychological readiness.

Conclusions

This study highlights the differential impact of physical function factors on specific subcategories of the ACL-RSI scale, providing clinicians with insights for designing targeted rehabilitation strategies. This original paper suggests the importance of analysing factors related to subcategory scores in addition to total ACL-RSI score, and could contribute to the understanding of determinants for a successful return to sport following ACL reconstruction.

Level of Evidence

Level IV.

Optimising the Early-Stage Rehabilitation Process Post-ACL Reconstruction

Outcomes following anterior cruciate ligament reconstruction (ACLR) need improving, with poor return-to-sport rates and a high risk of secondary re-injury. There is a need to improve rehabilitation strategies post-ACLR, if we can support enhanced patient outcomes. This paper discusses how to optimise the early-stage rehabilitation process post-ACLR. Early-stage rehabilitation is the vital foundation on which successful rehabilitation post-ACLR can occur. Without high-quality early-stage (and pre-operative) rehabilitation, patients often do not overcome major aspects of dysfunction, which limits knee function and the ability to transition through subsequent stages of rehabilitation optimally. We highlight six main dimensions during the early stage: (1) pain and swelling; (2) knee joint range of motion; (3) arthrogenic muscle inhibition and muscle strength; (4) movement quality/neuromuscular control during activities of daily living (5) psycho-social-cultural and environmental factors and (6) physical fitness preservation. The six do not share equal importance and the extent of time commitment devoted to each will depend on the individual patient. The paper provides recommendations on how to implement these into practice, discussing training planning and programming, and suggests specific screening to monitor work and when the athlete can progress to the next stage (e.g. mid-stage rehabilitation entry criteria).

Sports activity level after ACL reconstruction is predicted by vastus medialis or vastus medialis obliquus thickness, single leg triple hop distance or 6-m timed hop, and quality of life score

PURPOSE

Recovery after anterior cruciate ligament reconstruction (ACLR) may take > 2 years, and younger athletes have higher re-injury risk. The purpose of this prospective longitudinal study was to determine how the early to mid-term Tegner Activity Level Scale (TALS) scores of athletically active males ≥ 2 years post-ACLR follow-up was predicted by bilateral isokinetic knee extensor and flexor torque, quadriceps femoris thickness, single leg hop test performance, and self-reported knee function (Knee Injury and Osteoarthritis Outcome Score (KOOS); International Knee Documentation Committee (IKDC) Subjective Assessment score).

METHODS

After ACLR with a hamstring tendon autograft and safely returning to sports at least twice weekly, 23 men (18.4 ± 3.5 years of age) were evaluated at final follow-up (mean = 4.5, range = 2-7 years). Exploratory forward stepwise multiple regression was used to determine the relationship between independent surgical and non-surgical lower limb variables peak concentric isokinetic knee extensor-flexor torque at 60°/sec and 180°/sec, quadriceps femoris muscle thickness, single leg hop test profile results, KOOS subscale scores, IKDC Subjective Assessment scores, and time post-ACLR on TALS scores at final follow-up.

RESULTS

Subject TALS scores were predicted by KOOS quality of life subscale score, surgical limb vastus medialis obliquus (VMO) thickness, and surgical limb single leg triple hop for distance (SLTHD) performance. Subject TALS scores were also predicted by KOOS quality of life subscale score, non-surgical limb vastus medialis (VM) thickness, and non-surgical limb 6 m single leg timed hop (6MSLTH) performance.

CONCLUSION

TALS scores were influenced differently by surgical and non-surgical lower extremity factors. At ≥ 2 years post-ACLR, ultrasound VM and VMO thickness measurements, single leg hop tests that challenge knee extensor function, and self-reported quality of life measurements predicted sports activity levels. The SLTHD test may be better than the 6MSLTH for predicting long-term surgical limb function.

Differences in the microstructural and mechanical qualities of semitendinosus tendon grafts between skeletally immature and mature patients in anterior cruciate ligament reconstruction

BACKGROUND

This study aimed to investigate the microstructural and mechanical properties of semitendinosus tendon graft tissues during anterior cruciate ligament reconstruction and the clinical outcomes in skeletally immature and mature patients.

METHODS

Twenty-two patients who underwent primary anterior cruciate ligament reconstruction using a hamstring tendon graft were analyzed and divided into skeletally immature (n = 7) and mature groups (n = 15) based on magnetic resonance imaging findings of the epiphyseal plate of the distal femur. Tissue samples were collected from the mid-portion of the semitendinosus tendon. The collagen fibril diameter, maximum stress, and strain at maximum stress point in the semitendinosus tendon tissues were calculated for comparison of the microstructural and mechanical properties between the two groups. Postoperative outcomes were also assessed between the two groups.

RESULTS

The mean and 60th and 80th percentiles of fibril diameters in the skeletally immature group were significantly smaller than those in the mature group (65.9 ± 13.0, 73.5 ± 19.3, and 91.3 ± 27.4 nm in the skeletally immature group; and 90.3 ± 14.7, 94.0 ± 18.4, and 125.3 ± 19.9 nm in the skeletally immature group; p = 0.001, 0.024, and 0.004, respectively). Additionally, the strain at maximum stress was higher in the skeletally immature group (237.2 ± 102.4% vs. 121.5 ± 51.9%, p = 0.024). However, there was no difference in maximum stress between the skeletally immature and mature groups (19.9 ± 14.3 MPa vs. 24.5 ± 23.4 MPa, p = 0.578). Strain was negatively correlated with the mean fibril diameter and the 60th and 80th percentiles of fibril diameters, whereas stress was positively correlated with the mean fibril diameter. The skeletally immature group had a higher pivot shift test-positive rate than the mature group at the last follow-up (p = 0.023).

CONCLUSION

Semitendinosus tendon graft tissues differed microstructurally and mechanically between skeletally immature and mature patients.

LEVEL OF EVIDENCE

Level Ⅳ.

Similar outcomes after anterior cruciate ligament reconstruction in paediatric and adult populations: a 1-year follow-up of 506 paediatric operations in Denmark

PURPOSE

To present 1-year results after all paediatric anterior cruciate ligament (ACL) reconstructions in Denmark (5.9 M inhabitants) for the 10½ year period, 1 July 2011 to 31 December 2021.

METHODS

All children who had an ACL reconstruction were enrolled. They were asked to complete Pedi-IKDC preoperatively and at 1-year follow-up. Independent observers performed pivot shift test and instrumented laxity assessment preoperatively and at 1-year follow-up.

RESULTS

The median age of the 506 children (47.2% girls) was 14.3 years (9.3-15.9). The Pedi-IKDC score increased from preoperatively 61.6 ± 15.8 (mean ± SD) to 85.9 ± 13.0 at 1-year follow-up (p < 0.0001). There were concomitant injuries (to meniscus and/or cartilage) in 49.9%, but these children had preoperative and follow-up Pedi-IKDC scores similar to the scores for children with isolated injury to ACL (n. s.). Instrumented anterior laxity was 4.3 ± 1.4 (mean ± SD) mm preoperatively and 1.4 ± 1.4 mm at follow-up (p < 0.0001). Preoperatively, 3% had no pivot shift whilst this was the case for 68% postoperatively (p < 0.0001). Twenty-five children (5.6%) had 4 mm instrumented laxity or more relative to the unoperated knee at follow-up. Two patients (0.4%) had an operatively treated deep infection, three (0.5%) were operated on for reduced range of motion and two (0.4%) had a revision ACL reconstruction.

CONCLUSION

ACL reconstruction resulted in a clinically meaningful increase in Pedi-IKDC, an improved instrumented stability, a reduction in the grade of pivot shift and the complication rate was low at 1-year follow-up. The risk of graft insufficiency at 1-year follow-up was the same as in an adult population.

LEVEL OF EVIDENCE

II.

Assessment of Return to Sport After ACL Reconstruction With Soft Tissue Autograft in Adolescent Athletes: Quadriceps Versus Hamstring Tendon

Background

Quadriceps tendon soft tissue autograft represents an increasingly popular graft option for anterior cruciate ligament reconstruction (ACLR), particularly for adolescents, some of whom have an open physis, precluding use of graft options with bone plugs.

Purpose/Hypothesis

The purpose of this study was to quantify return-to-sport performance assessments in adolescents at 6 months after ACLR with all-soft tissue quadriceps tendon autograft (ACLR-Q) versus hamstring tendon autograft (ACLR-HS). It was hypothesized that ACLR-Q would be associated with improved hamstring strength and hamstring-to-quadriceps (HS:Q) ratios compared with ACLR-HS, albeit with decreased quadriceps strength.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Included were patients aged 12 to 19 years who underwent primary ACLR by a single surgeon and who completed a return-to-sport performance assessment between 5 and 9 months postoperatively. The performance assessment included manual muscle strength tests (hamstring, quadriceps, hip abductor and adductor), dynamic balance test (Y-balance), and functional hop tests (single hop, triple hop, crossover hop, 6-m timed hop). Data were converted to limb symmetry indices, and limb symmetry index deficits were compared between the ACLR-Q and ACLR-HS cohorts using the Student t test or Wilcoxon-Mann-Whitney test.

Results

An initial cohort of 90 ACLR-Q patients was compared with 54 ACLR-HS patients, with no significant differences in patient characteristics. Differences in meniscal repair rates, however, prompted use of propensity score matching on age, sex, body mass index, meniscectomy, and meniscal repair to produce comparable subcohorts. The matching resulted in 67 ACLR-Q and 52 ACLR-HS patients. Hamstring strength deficits were significantly greater in ACLR-HS versus ACLR-Q patients (-40.5% vs -5.7%; P < .001). Quadriceps strength deficits were significantly greater in ACLR-Q versus ACLR-HS patients (-12.8% vs -0.4%; P < .001). ACLR-Q patients had a significantly greater HS:Q ratio on the operative knee (P < .001) and significantly higher Y-balance composite score deficits (-2.9% vs -0.4%; P = .01) than ACLR-HS patients. There were no significant differences in hop test performance between groups.

Conclusion

Adolescent athletes who underwent ACLR-Q showed significantly greater quadriceps strength deficits but significantly smaller hamstring strength deficits than those who underwent ACLR-HS, leading to more favorable HS:Q ratios in ACLR-Q patients at 6 months postoperatively.

Growth progression of anterior cruciate ligament bone grafts in a pediatric population: magnetic resonance imaging analysis

BACKGROUND

In children, the incidence of anterior cruciate ligament (ACL) ruptures and reconstructions has significantly risen. Unfortunately, re-rupture rates following surgery are substantially higher in children than adults. Previous research suggests that smaller graft diameters are predictive of re-rupture.

OBJECTIVE

This study aimed to investigate the growth progression of the ACL bone graft, specifically in terms of width and length, within the intra-articular portion and tunnels, using successive magnetic resonance imaging (MRI) scans. The hypothesis was that the ACL grafts would undergo thinning during growth.

MATERIALS AND METHODS

The cohort comprised 100 patients who underwent ACL reconstruction. Among them, 37 patients with significant residual growth were selected for analysis. Of these, 4 patients experienced graft rupture, 5 had "over-the-top" techniques, 12 had missing MRI scans and 5 were lost to follow-up. Each included patient underwent two MRI scans; the analyses of which were conducted in a double-masked manner.

RESULTS

A total of 13 knees (and patients) were analyzed, with a mean ± SD (range) delay of residual growth between the two MRI scans of 3.3 + / - 1.4 (1.2-5.2) years. The graft exhibited elongation, thinning and eventual integration with the surrounding bone in the tunnels. Within the intra-articular portion, the mean [95% CI] increase in graft size between the two MRI scans was 30.8% in length and 14.8% in width. The width/length ratio in the intra-articular part was 20.4% on the first MRI and 20.8% on the second MRI. Since this difference in the ratio (+ 0.4%) was not statistically significant (P=0.425), our results indicate that the grafts remained stable in terms of proportions without thinning or thickening. Therefore, the initial hypothesis was validated for the tunnel portion but not the intra-articular portion of the grafts.

CONCLUSION

In children with open physes, ACL grafts demonstrate smooth growth progression in all dimensions. However, this finding does not fully explain the high rate of re-rupture observed in children. Further research is needed to elucidate the underlying factors contributing to re-rupture in this population.

Factors Associated With Sports Function and Psychological Readiness to Return to Sports at 12 Months After Anterior Cruciate Ligament Reconstruction: A Cross-sectional Study

BACKGROUND

Sports function and psychological readiness to return to sports (RTS) are important outcomes when evaluating rehabilitation after anterior cruciate ligament reconstruction (ACLR). It is, however, unclear which specific factors contribute most to these outcomes.

PURPOSE

To determine associations between demographic characteristics, objective measurements of physical function, patient-reported outcome measure scores, sports-related function assessed with the Knee injury and Osteoarthritis Outcome Score (KOOS) Sport and Recreation subscale, and psychological readiness to RTS assessed with the Anterior Cruciate Ligament-Return to Sport after Injury (ACL-RSI) scale at 1 year after ACLR.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

At a mean of 12.5 ± 2.0 months after ACLR, 143 participants (50.3% female), with a mean age of 25.0 ± 5.7 years, were assessed for demographic characteristics, physical factors (hop performance, muscle strength, ankle and hip range of motion), and psychological factors (KOOS Pain and Symptoms subscales, Perceived Stress Scale, fear of reinjury) as well as the KOOS Sport and Recreation subscale and ACL-RSI scale. Backward linear regression models were used to evaluate factors associated with sports function and psychological readiness to RTS.

RESULTS

Lower isokinetic knee extension peak torque (limb symmetry index) (B = 18.38 [95% CI, 3.01-33.75]), lower preinjury activity level (B = 2.00 [95% CI, 0.87-3.14]), greater knee pain (B = 0.90 [95% CI, 0.70-1.10]), shorter time between injury and reconstruction (B = 0.16 [95% CI, 0.05-0.26]), and greater fear of reinjury (B = 0.11 [95% CI, 0.01-0.20]) were associated with a worse KOOS Sport and Recreation subscore (R2 = 0.683). A shorter hop distance (B = 0.15 [95% CI, 0.00-0.29]) was associated with a lower ACL-RSI score (R2 = 0.245).

CONCLUSION

A combination of knee muscle strength, activity level, knee pain, timing of surgery, and fear of reinjury accounted for approximately 70% of the variation in sports function at 1 year after ACLR. In contrast, there was only 1 weak association between physical function and psychological readiness to RTS at this time point. Thus, factors associated with current sports function are much better known than features related to psychological readiness to RTS.

Neuromuscular control in males and females 1 year after an anterior cruciate ligament rupture or reconstruction during stair descent and artificial tibial translation

Neuromuscular alterations are reported in patients with anterior cruciate ligament reconstruction (ACL-R) and conservative treatment (copers with ACL deficiency, ACL-C). However, it is unclear whether sex influences neuromuscular control. The objective was to investigate differences in neuromuscular control regarding sex and treatment type one year after ACL rupture in comparison to a group with an intact ACL (ACL-I). Electromyography of vastus medialis (VM) and lateralis, biceps femoris (BF) and semitendinosus (ST) was recorded in ACL-R (N = 38), ACL-C (N = 26), and ACL-I (N = 38) during stair descent and reflex activity by anterior tibial translation while standing. The movements of stair descent were divided into pre-activity, weight-acceptance and push-off phases, reflex activity in pre-activation, short, medium (MLR), and long latency responses (LLR). Normalized root mean squares for each muscle of involved and matched control limb per phase were calculated and analyzed with two-way ANOVA (α = 0.05). During stair descent, neuromuscular differences of BF were significant during push-off only (p = 0.001). Males of ACL-R and ACL-C had higher BF activity compared to ACL-I (p = 0.009, 0.007 respectively). During reflex activity, VM and BF were significantly different between treatment groups for pre-activation (p = 0.013, 0.035 respectively). VM pre-activation of females was higher in ACL-R compared to ACL-C (p = 0.018), and lower in ACL-C compared to ACL-I (p = 0.034). Males of ACL-R showed higher VM and less BF pre-activation (p = 0.025, p = 0.003 respectively) compared to ACL-I. Males of ACL-C had less BF pre-activation compared to ACL-I (p = 0.019). During MLR, intra-group differences in ST were found for treatment (p = 0.011) and females of ACL-R compared to ACL-I (p = 0.015). During LLR, overall intra-group differences in VM were present for treatment (p = 0.034) and in females (ACL-R versus ACL-C (p = 0.015), ACL-I (p = 0.049), respectively). One year after an ACL rupture, neuromuscular alterations persist regardless of treatment and sex. Standard rehabilitation protocols may not be able to restore neuromuscular control. Future research should include long-term follow up and focus on exercises targeting neuromuscular function.

Major Increase in Incidence of Pediatric ACL Reconstructions From 2005 to 2021: A Study From the Norwegian Knee Ligament Register

BACKGROUND

The incidence of pediatric and adolescent anterior cruciate ligament reconstruction (ACLR) is increasing in several countries. It is uncertain whether this trend applies to countries that traditionally prefer an initial nonoperative treatment approach whenever possible, like Norway. Nationwide, long-term patient-reported outcomes and revision rates after ACLR in the pediatric population are also lacking.

PURPOSE

To determine the incidence of pediatric ACLR in Norway since 2005, as well as to detect trends in surgical details and describe patient-reported outcomes up to 10 years after ACLR.

STUDY DESIGN

Descriptive cohort study.

METHODS

This study is based on prospectively collected data on girls ≤14 years and boys ≤16 years, registered in the Norwegian Knee Ligament Register at the time of their primary ACLR, between 2005 and 2021. The main outcome was the incidence of ACLR, adjusted to the corresponding population numbers for each year. The time trend was analyzed by comparing the mean of the first and last 3-year period (2005-2007 and 2019-2021). Patient-reported outcomes were assessed using the Knee injury and Osteoarthritis Outcome Score preoperatively and at 2, 5, and 10 years postoperatively.

RESULTS

A total of 1476 patients (1484 cases) were included, with a mean follow-up of 8.1 years (range, 1-17). The incidence of pediatric ACLRs per 100,000 population increased from 18 to 26, which corresponds to an increase of 40% for boys and 55% for girls. Concurrent meniscal procedures increased significantly from 45% to 62%, and the proportion of meniscal repairs increased from 19% to 43% when comparing the first and last time period. The mean Knee injury and Osteoarthritis Outcome Score values for the Sport and Recreation and Quality of Life subscales were between 72 and 75 at the 2-, 5- and 10-year follow-up. The 5-year revision rate was 9.9%.

CONCLUSION

There was a major increase in incidence of pediatric ACLR in Norway during the study period. There was a shift in the approach to concomitant meniscal procedures from resection to repair, with more than a doubling of the proportion of meniscal repairs. Patient-reported outcomes revealed long-lasting reduced knee function.

The Association of Physical Competence With Psychological Response Among Young Athletes at Time of Return to Sport After ACL Reconstruction

BACKGROUND

The traditional index of return-to-sport (RTS) readiness after anterior cruciate ligament reconstruction (ACLR) is the achievement of physical competence criteria. Emerging research indicates that psychological response and self-perceptions of physical competence may be critical mechanisms for successful RTS among young athletes.

HYPOTHESIS

Young athletes with higher actual physical competence (APC) and perceived physical competence (PPC) will demonstrate a more positive psychological response at the time of RTS after ACLR.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 41 young athletes after primary ACLR completed testing within 8 weeks of medical clearance to RTS. APC was measured with isokinetic knee extension strength, single-limb crossover hop for distance, and the Knee injury and Osteoarthritis Outcome Score. PPC was measured with the Athletic Competence subscale of the Self-Perception Profile. Criteria for APC and PPC were based on established age- and activity-relevant cutoff scores. Different constructs of psychological response were assessed with the adapted Sport Motivation Scale, Brief Resilience Scale, and Anterior Cruciate Ligament Return to Sport after Injury (ACL-RSI) total and subscale scores (Emotions, Confidence, and Risk Appraisal). Multiple linear regression analyses were used to determine differences in measures of psychological response based on achievement of APC and PPC, while adjusting for age and sex.

RESULTS

Of the 41 participants, 10 (24.4%) met all criteria for APC and 22 (53.7%) met the PPC criteria. The regression models estimating the ACL-RSI score (P < .001; adjusted R2 = 0.331), ACL-RSI Emotions score (P < .001; adjusted R2 = 0.427), and ACL-RSI Risk Appraisal score (P = .013; adjusted R2 = 0.212) were statistically significant. Although APC was not associated with any measure of psychological response, meeting PPC criteria, younger age, and male sex were found to be associated with a more positive psychological readiness to RTS, but not with motivation or resilience.

CONCLUSION

Meeting PPC criteria was associated with higher psychological readiness to RTS among young athletes after ACLR, while meeting APC criteria was not associated with any construct of psychological response.

No increase in adverse events with lateral extra-articular tenodesis augmentation of anterior cruciate ligament reconstruction - Results from the stability randomized trial

OBJECTIVES

Results from the Stability Study suggest that adding a lateral extra-articular tenodesis (LET) to a hamstring tendon autograft reduces the rate of anterior cruciate ligament reconstruction (ACLR) failure in high-risk patients. The purpose of this study is to report adverse events over the 2-year follow-up period and compare groups (ACLR alone vs. ACLR + LET).

METHODS

Stability is a randomized clinical trial comparing hamstring tendon ACLR with and without LET. Patients aged 14-25 years with an ACL deficient knee were included. Patients were followed and adverse events documented (type, actions taken, resolution) with visits at 3, 6, 12, and 24 months postoperatively. Adverse events were categorized as none, minor medical, minor surgical, contralateral ACL rupture, or graft rupture. Patient reported outcome measures (PROMs) collected at each visit included the Knee Injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee Score (IKDC), and ACL Quality of Life Questionnaire (ACL-QOL).

RESULTS

In total, 618 patients were randomized (mean age 18.9 years, 302 (49%) male). Forty-five patients (7%) suffered graft rupture; 34 (11%) in the ACLR group compared to 11 (4%) in the ACLR + LET group (RRR = 0.67, 95% CI 0.36 to 0.83, p < 0.001). There were no differences in effusion or infection rates between groups. The ACLR + LET group experienced an increased number of hardware removals (10 vs. 4). Overall, the rate of minor medical events (11%), minor surgical events (7%), and ipsilateral or contralateral ACL tears (10%) were low considering the high-risk patient profile. Increasing severity of adverse events was associated with lower PROMs at 24 months post-operative. Patients in the ACLR + LET group reported greater degree of pain at 3 months only. There were no clinically significant differences in range of motion between groups.

CONCLUSIONS

The addition of LET to hamstring tendon autograft ACLR in young patients at high risk of re-injury resulted in a statistically significant reduction in graft rupture. While the addition of LET may increase rates of hardware irritation, there was no significant increase in overall rates of minor medical adverse events, minor surgical events, or overall re-operation rates. The concerns regarding complications associated with a LET did not materialize in this study.

LEVEL OF EVIDENCE

Level I.

Reduced Incidence of Revision Anterior Cruciate Ligament Reconstruction With Internal Brace Augmentation

Background

Revision rates and outcome measures after anterior cruciate ligament reconstruction (ACLR) with suture tape as an internal brace is not well-documented because of the emerging nature of the technique.

Hypothesis

ACLR with internal bracing (IB) would lead to decreased revision ACLR compared with traditional ACLR while exhibiting comparable patient outcomes.

Study Design

Cohort study; Level of evidence, 3.

Methods

A total of 200 patients were included in this study. Patients aged between 13 and 39 years at the time of surgery who underwent primary autograft ACLR with IB between 2010 and 2020 and were enrolled in our institution's registry with a minimum of 2-year follow-up were identified and matched 1 to 1 with a non-internal brace (no-IB) group based on concomitant procedures and patient characteristics. Pre- and postoperatively, patients completed the Knee injury and Osteoarthritis Outcome Score, Marx activity rating scale, Veterans RAND 12-Item Health Survey, and visual analog scale for pain. Knee laxity measurements via the KT-1000 arthrometer were included in the pre- and postoperative objective clinical assessments.

Results

A total of 100 IB patients were matched with 100 no-IB patients based primarily on concomitant procedures and secondarily on patient characteristics. The IB group underwent significantly fewer revision ACLRs (1% vs 8%; P = .017). Even though the no-IB group had a significantly longer mean final follow-up time (48.6 months [95% CI, 45.4-51.7] vs 33.4 months [95% CI, 30.3-36.5]; P < .001), the time elapsed from the original ACLR to the revision did not differ significantly between groups, and the mean ages for the IB and no-IB groups were comparable (19 vs 19.9 years). All postoperative patient-reported outcome scores between the 2 groups were comparable and significantly improved postoperatively except for the Marx score, which significantly decreased stepwise for both groups postoperatively. KT-1000 measurements significantly improved in both groups after surgery with the IB and no-IB cohorts yielding comparable results at the manual maximum pull (0.97 vs 0.65 mm).

Conclusion

ACLR with IB resulted in a significantly decreased risk of revision ACLRs while maintaining comparable patient-reported outcomes. Therefore, incorporating an internal brace into ACLR appears to be safe and effective within these study parameters.

Anterior Cruciate Ligament Rehabilitation for the 10- to 18-Year-Old Adolescent Athlete: Practice Guidelines Based on International Delphi Consensus

Background

There are 2 treatment options for adolescent athletes with anterior cruciate ligament (ACL) injuries-rehabilitation alone (nonsurgical treatment) or ACL reconstruction plus rehabilitation. However, there is no clear consensus on how to include strength and neuromuscular training during each phase of rehabilitation.

Purpose

To develop a practical consensus for adolescent ACL rehabilitation to help provide care to this age group using an international Delphi panel.

Study Design

Consensus statement.

Methods

A 3-round online international Delphi consensus study was conducted. A mix of open and closed literature-based statements were formulated and sent out to an international panel of 20 ACL rehabilitation experts. Statements were divided into 3 domains as follows: (1) nonsurgical rehabilitation; (2) prehabilitation; and (3) postoperative rehabilitation. Consensus was defined as 70% agreement between panel members.

Results

Panel members agreed that rehabilitation should consist of 3 criterion-based phases, with continued injury prevention serving as a fourth phase. They also reached a consensus on rehabilitation being different for 10- to 16-year-olds compared with 17- and 18-year-olds, with a need to distinguish between prepubertal (Tanner stage 1) and mid- to postpubertal (Tanner stages 2-5) athletes. The panel members reached a consensus on the following topics: educational topics during rehabilitation; psychological interventions during rehabilitation; additional consultation of the orthopaedic surgeon; duration of postoperative rehabilitation; exercises during phase 1 of nonsurgical and postoperative rehabilitation; criteria for progression from phase 1 to phase 2; resistance training during phase 2; jumping exercises during phase 2; criteria for progression from phase 2 to phase 3; and criteria for return to sports (RTS). The most notable differences in recommendations for prepubertal compared with mid- to postpubertal athletes were described for resistance training and RTS criteria.

Conclusion

Together with available evidence, this international Delphi statement provides a framework based on expert consensus and describes a practice guideline for adolescent ACL rehabilitation, which can be used in day-to-day practice. This is an important step toward reducing practice inconsistencies, improving the quality of rehabilitation after adolescent ACL injuries, and closing the evidence-practice gap while waiting for further studies to provide clarity.

Incidence of anterior cruciate ligament injury patterns in Japanese judo players from a nationwide insurance database

Objective

This study aimed to characterize the age- and sex-specific Anterior cruciate ligament (ACL) injury rates and related injury patterns in judo players in Japan using the nationwide insurance database.

Methods

This was a descriptive epidemiological study. We examined a total of 2142 adolescents with anterior cruciate ligament injuries registered in the insurance system of the Japan Sports Council between January 2009 and December 2018. The age- and sex-specific incidences were estimated for the levels of 7th, 8th, and 9th grades of junior high school and 10th, 11th, and 12th grades of high school. The anterior cruciate ligament injury circumstances were classified into three patterns based on the impact to the involved knee: high-impact valgus force, low-impact trunk displacement, or no-impact knee twisting.

Results

The incidence of anterior cruciate ligament injury from the 7th to 12th grades were 0.5, 0.9, 0.9, 6.9, 8.6, and 6.1 per 1000 athlete-years in male players and 1.3, 3.8, 3.4, 16.8, 19.5, and 13.6 per 1000 athlete-years in female players. The most prevalent injury pattern was a low-impact contact injury (42.6%) with Osoto-gari, followed by a high-impact contact injury (29.8%). The concomitant medial collateral ligament (MCL) injury rate was 18.1%, which was correlated with a high-impact contact injury (p = 0.005) by multiple regression analysis.

Conclusions

The highest incidence of age- and sex-specific anterior cruciate ligament injury was 19.5 per 1000 athlete-years in female high school students in the 11th grade. The most frequent injury pattern was low-impact contact injury with trunk displacement, indicating that trunk stabilization training could help prevent anterior cruciate ligament injury in judo.

Lateral Extra-articular Tenodesis with Iliotibial Band Using Knotless All-Suture Anchor Femoral Fixation

Common injuries, such as anterior cruciate ligament (ACL) tears, can result in both anterior and rotational instability of the knee. An arthroscopic anterior cruciate ligament reconstruction (ACLR) method has been shown to be effective in restoring anterior translational stability, but this could be followed by persistent rotational instability by means of residual pivot shifts or repeat instability episodes. Alternative techniques, such as a lateral extraarticular tenodesis (LET), has been proposed as a technique for preventing persistent rotational instability following ACLR. This article presents a case of a LET using an autologous central slip of iliotibial (IT) band with fixation to the femur using a 1.8-mm knotless all-suture anchor.

Graft-Specific Surgical and Rehabilitation Considerations for Anterior Cruciate Ligament Reconstruction with the Quadriceps Tendon Autograft

Anterior cruciate ligament reconstruction (ACLR) with a bone-patellar tendon-bone (BPTB) or hamstring tendon (HT) autograft has traditionally been the preferred surgical treatment for patients returning to Level 1 sports. More recently, international utilization of the quadriceps tendon (QT) autograft for primary and revision ACLR has increased in popularity. Recent literature suggests that ACLR with the QT may yield less donor site morbidity than the BPTB and better patient-reported outcomes than the HT. Additionally, anatomic and biomechanical studies have highlighted the robust properties of the QT itself, with superior levels of collagen density, length, size, and load-to-failure strength compared to the BPTB. Although previous literature has described rehabilitation considerations for the BPTB and HT autografts, there is less published with respect to the QT. Given the known impact of the various ACLR surgical techniques on postoperative rehabilitation, the purpose of this clinical commentary is to present the procedure-specific surgical and rehabilitation considerations for ACLR with the QT, as well as further highlight the need for procedure-specific rehabilitation strategies after ACLR by comparing the QT to the BPTB and HT autografts.

Level of Evidence

Level 5.

A scoping review of portable sensing for out-of-lab anterior cruciate ligament injury prevention and rehabilitation

Anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) surgery are common. Laboratory-based biomechanical assessment can evaluate ACL injury risk and rehabilitation progress after ACLR; however, lab-based measurements are expensive and inaccessible to most people. Portable sensors such as wearables and cameras can be deployed during sporting activities, in clinics, and in patient homes. Although many portable sensing approaches have demonstrated promising results during various assessments related to ACL injury, they have not yet been widely adopted as tools for out-of-lab assessment. The purpose of this review is to summarize research on out-of-lab portable sensing applied to ACL and ACLR and offer our perspectives on new opportunities for future research and development. We identified 49 original research articles on out-of-lab ACL-related assessment; the most common sensing modalities were inertial measurement units, depth cameras, and RGB cameras. The studies combined portable sensors with direct feature extraction, physics-based modeling, or machine learning to estimate a range of biomechanical parameters (e.g., knee kinematics and kinetics) during jump-landing tasks, cutting, squats, and gait. Many of the reviewed studies depict proof-of-concept methods for potential future clinical applications including ACL injury risk screening, injury prevention training, and rehabilitation assessment. By synthesizing these results, we describe important opportunities that exist for clinical validation of existing approaches, using sophisticated modeling techniques, standardization of data collection, and creation of large benchmark datasets. If successful, these advances will enable widespread use of portable-sensing approaches to identify ACL injury risk factors, mitigate high-risk movements prior to injury, and optimize rehabilitation paradigms.

Using load sensing insoles to identify knee kinetic asymmetries during landing in patients with an Anterior Cruciate Ligament reconstruction

BACKGROUND

Knee extension moment asymmetry is a known second anterior cruciate ligament injury risk factor in patients who have had an anterior cruciate ligament reconstruction. Traditionally, assessing asymmetries requires motion capture and force platforms which are expensive and occupy a large space. Wireless force sensing insoles could be a feasible surrogate.

METHODS

Twenty-nine patients following anterior cruciate ligament reconstruction performed ten bilateral stop jumps while insole forces, ground reaction forces, and lower extremity kinematics were collected. Peak knee extension moment symmetry was computed using the kinematic and kinetic data, and peak impact force symmetry and impulse symmetry were computed using both the insole force data and vertical ground reaction force data. The relationship between outcomes was analyzed using Pearson correlation coefficients. Patients were classified as symmetric or asymmetric for each outcome based on an 85% symmetry cutoff. The resulting classifications were qualitatively compared across outcome measures.

FINDINGS

Peak knee extension moment symmetry had a strong association with the force plate symmetry outcomes (r = 0.72-0.96, p < 0.001) and a moderate to strong association with insole symmetry outcomes (r = 0.67-0.77, p < 0.001). There was strong agreement between insole and force plate symmetry outcomes (r = 0.69-0.90, p < 0.001). Four patients were identified as symmetric when using the peak knee extension moment symmetry, five when using force plate data, and eight when using insole data.

INTERPRETATION

Force sensing insoles could be used as a surrogate for knee extension moment asymmetry in patients who have had an anterior cruciate ligament reconstruction.

Secondary Anterior Cruciate Ligament Injury Prevention Training in Athletes: What Is the Missing Link?

After reconstruction, the return to full competition rate of athletes is low, while the re-injury rate remains high despite the completion of a rehabilitation programme. Primary ACL prevention programmes are well developed, yet few research papers focus on secondary ACL injury prevention. The aim of current review is to determine if current ACL secondary prevention training has a positive influence on the re-injury rate, the clinical or functional outcomes, or the risk of re-injury in athletes. Studies investigating secondary prevention of ACL were searched in PubMed and EBSCOhost, followed by a review of the references in the identified articles. The existing evidence suggests that neuromuscular training, eccentric strengthening, and plyometric exercises may have a potential impact on improving biomechanical, functional, and psychological outcomes in athletes; however, the studies on the prevention of second ACL injury in athletes is scarce and inconclusive. Future research is needed to investigate the effectiveness of secondary ACL prevention in reducing the re-injury rates. (PROSPERO Registration number: CRD42021291308).

Clinical Research Progress of Internal Brace Ligament Augmentation Technique in Knee Ligament Injury Repair and Reconstruction: A Narrative Review

Knee ligament injuries are most common in sports injuries. In general, ligament repair or reconstruction is necessary to restore the stability of the knee joint and prevent secondary injuries. Despite advances in ligament repair and reconstruction techniques, a number of patients still experience re-rupture of the graft and suboptimal recovery of motor function. Since Dr. Mackay's introduction of the internal brace technique, there has been continuous research in recent years using the internal brace ligament augmentation technique for knee ligament repair or reconstruction, particularly in the repair or reconstruction of the anterior cruciate ligament. This technique focuses on increasing the strength of autologous or allograft tendon grafts through the use of braided ultra-high-molecular-weight polyethylene suture tapes to facilitate postoperative rehabilitation and avoid re-rupture or failure. The purpose of this review is to present detailed research progress in the internal brace ligament enhancement technique of knee ligament injury repair as well as the reconstruction from biomechanical and histological research and clinical studies and to comprehensively assess the value of the application of this technique.

Predicting anterior cruciate ligament failure load with T2* relaxometry and machine learning as a prospective imaging biomarker for revision surgery

Non-invasive methods to document healing anterior cruciate ligament (ACL) structural properties could potentially identify patients at risk for revision surgery. The objective was to evaluate machine learning models to predict ACL failure load from magnetic resonance images (MRI) and to determine if those predictions were related to revision surgery incidence. It was hypothesized that the optimal model would demonstrate a lower mean absolute error (MAE) than the benchmark linear regression model, and that patients with a lower estimated failure load would have higher revision incidence 2 years post-surgery. Support vector machine, random forest, AdaBoost, XGBoost, and linear regression models were trained using MRI T2* relaxometry and ACL tensile testing data from minipigs (n = 65). The lowest MAE model was used to estimate ACL failure load for surgical patients at 9 months post-surgery (n = 46) and dichotomized into low and high score groups via Youden's J statistic to compare revision incidence. Significance was set at alpha = 0.05. The random forest model decreased the failure load MAE by 55% (Wilcoxon signed-rank test: p = 0.01) versus the benchmark. The low score group had a higher revision incidence (21% vs. 5%; Chi-square test: p = 0.09). ACL structural property estimates via MRI may provide a biomarker for clinical decision making.

Lateral Extra-Articular Tenodesis via an All-Suture Anchor

Background:

In young patients, anterior cruciate ligament (ACL) reconstruction often results in graft failure. This may be due, in part, to concomitant injury to anterolateral complex (ALC) of the knee leading to rotatory laxity. The modified Lemaire lateral extra-articular tenodesis (LET) technique is intended to address the anterolateral rotatory instability due to injury to the ALC and to protect the ACL graft and meniscus.

Indications:

The International Anterolateral Complex Consensus Group Meeting identified 4 appropriate indications for the modified Lemaire LET procedure: revision ACL, high-grade pivot shift, generalized ligamentous laxity/genu recurvatum, and young patients returning to pivoting activities.

Technique Description:

The technique consists of harvesting an 8-cm long by 1-cm wide graft from the iliotibial band. The graft is released proximally and remains attached distally to Gerdy’s tubercle. The graft is then passed deep to the lateral collateral ligament (LCL) from distal to proximal. The graft is then affixed to a point proximal and posterior to the lateral femoral epicondyle with an all-suture button. The graft is then tensioned with knee at 30° of flexion and neutral rotation, and then secured in place.

Results:

With the modified Lemaire LET, there was previously concern for overconstraint and lateral compartment degeneration. However, recent studies have shown that there is no increased risk for these complications with the LET procedure. The STABILITY trial found that the addition of LET to ACL reconstruction significantly reduces re-rupture and residual laxity when compared with ACL reconstruction alone. Moreover, the addition of LET to ACL reconstruction can restore native knee kinematics.

Conclusion:

The addition of the modified Lemaire LET technique to traditional ACL reconstruction is a safe and effective adjunct that reduces the occurrence of graft rupture, addresses residual rotational laxity, and can restore native knee kinematics in appropriately indicated patient populations.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Combined anterolateral complex and anterior cruciate ligament injury: Anatomy, biomechanics, and management-State-of-the-art

Anterior cruciate ligament (ACL) rupture typically occurs because of sudden axial loading of the knee in conjunction with a coupled valgus and rotational moment about the tibia. However, the ACL is not the only structure damaged during this mechanism of injury, and studies have shown that the anterolateral complex (ALC) of the knee is also commonly involved. Biomechanical studies have established that the ALC plays an important role as a secondary stabiliser to control anterolateral rotatory laxity (ALRL). Indeed, it has been suggested that failure to address injury to the ALC at the time of ACL reconstruction (ACLR) may increase the risk of graft failure owing to persistent ALRL. The concept of combining a lateral extra-articular procedure to augment ACLR for the treatment of ACL injury emerged with a view to decrease the failure rate of either procedure in isolation. This state-of-the-art review discusses the history of the anatomy of the ALC, the biomechanics of a variety of lateral extra-articular augmentation procedures, and provides clinical guidelines for their use in primary ACLR.

The Bone Bridge for Tibial ACL Graft Fixation: A Biomechanical Analysis of Different Tibial Fixation Methods for ACL Reconstruction

Background

The tibial fixation site is considered the weak link in anterior cruciate ligament (ACL) reconstruction, and conflicting results regarding the biomechanical properties of various fixation methods have been reported.

Purpose

To examine knots tied over a bone bridge and its biomechanical properties as a suitable tibial fixation method in ACL reconstruction.

Study Design

Controlled laboratory study.

Methods

We divided 40 fresh-frozen porcine tibiae into 4 equal groups to evaluate flexor tendon grafts set with standard tibial fixation techniques: (1) bone bridge (BB group), (2) suspension button (SB group), (3) combined interference screw and bone bridge (IFS/BB group), and (4) combined interference screw and suspension button (IFS/SB group). Each construct was subjected to cyclic loading (1500 cycles, 50-250 N, 1 Hz) with a servohydraulic materials testing machine to measure elongation; load-to-failure testing (displacement rate: 25 mm/s) was then performed. Load to failure, stiffness, and yield load were compared between constructs using 1-way analysis of variance.

Results

The hybrid fixation constructs (IFS/BB and IFS/SB groups) showed significantly better biomechanical properties than the isolated extracortical fixation constructs (BB and SB groups) (P < .05 for all). There were no differences between the isolated extracortical fixation constructs or between the hybrid fixation constructs in elongation or load to failure; however, stiffness of the IFS/BB group was significantly higher than that of the IFS/SB group (175.3 ± 16.6 vs 144.9 ± 20.1 N/mm, respectively; P < .05). Stiffness between the SB and BB groups was not significantly different.

Conclusion

Hybrid fixation had superior biomechanical performance compared with isolated extracortical fixation. However, tibial graft fixation using a bone bridge either as isolated extracortical fixation or combined with an interference screw for hybrid fixation showed equivalent biomechanical properties compared with suspension button-based graft fixation.

Clinical Relevance

The clinical use of a bone bridge for tibial graft fixation could reduce the cost for ACL reconstruction and lower the rate of implant-associated issues.

Suture tape augmentation, a novel application of synthetic materials in anterior cruciate ligament reconstruction: A systematic review

Objective: Suture tape (ST) is a common synthetic material in the repairing surgery of soft tissue. Recently, ST augmentation (STA) technique has been described as a novel way to improve the mechanical property of grafts in the anterior cruciate ligament (ACL) reconstruction (ACLR). However, the clinical outcomes of ACLR using ST-augmented grafts have not been clarified. This systematic review aimed to summarize the specific technique of STA and evaluate the clinical outcomes after ACLR with STA. Methods: A electronic search of PubMed and Embase databases with a manual search of Google Scholar was performed to identify studies that reported the clinical outcomes of ACLR with STA. Each included study was abstracted regarding the study features, patient data, surgical information, and outcome measures. Results: Nine studies were included, representing 314 knees in 314 patients undergoing ACLR with STA. Technically, ST was fixed independently from grafts in six studies and along with grafts in two studies. Most studies applied an equal or slightly less tension on ST than ACL graft. Clinically, significant improvements were found in the Lysholm, IKDC, and KOOS scores after a mean follow-up of 16.7 months. Physical examinations of 220 patients showed significant restoration of knee stability at the final follow-up. 59 of 80 (73.8%) patients returned to preinjury sports level at a minimum 2 year follow-up. Six of 266 (2.3%) patients had a graft failure during the first 2 years postoperatively. The use of ST was significantly associated with better Tegner scores and a trend toward significantly higher rates of return to sport compared to standard ACLR. No significant difference was found in most subjective scores, knee laxity, and graft failures between ACLR with or without STA. Conclusion: ACLR with STA achieved overall favorable clinical outcomes. Patients using ST-augmented grafts were seemingly associated with better sports performance compared to standard ACLR. But ACLR with STA was not superior to ACLR alone in most functional scores, knee stability measures, and graft failure rates. A tension equal to or slightly less than the ACL graft should be carefully applied on ST during fixation to avoid stress shielding of the graft.

Increasing incidence of anterior cruciate ligament reconstruction: a 17-year population-based study

PURPOSE

Anterior cruciate ligament (ACL) injuries are one of the most frequently studied injuries in orthopedic care and research. However, limited epidemiological data are available in Canada regarding trend and distribution of anterior cruciate ligament reconstruction (ACLR). In this paper, our purpose was to assess trends of ACLR between 2002/03 and 2018/19 by age, sex, season of surgery, and location (inpatient vs outpatient) of surgery.

METHODS

In this descriptive epidemiological study of retrospective data available from Alberta Ministry of Health, we report annual incidence of ACLR between 2002/03 until 2018/19 among Albertans aged 10 years and older. Information was collected by authors from physician claims database for primary ACLR and revision ACLR and linked with other databases. Incidence proportions (number of ACLR/100,000 population) were calculated and compared by age category and gender over the study period.

RESULTS

A total of 28,401 primary ACLR and 2085 revision ACLR were identified during the study period. Age-standardized annual incidence of primary ACLR increased from 40.6 to 51.2 per 100,000 population aged 10 years and older. Average annual increase in ACLR incidence was higher among females (1.8% per years) compared to males (0.96% per year). The overall peak incidence and peak incidence among males was observed in 20-29 year age group, whereas peak incidence in females was observed in 10-19 years of age. The number of ACLR in females outnumbers those among males for 10-19 year age group. Generally, a lower proportion of ACLR were conducted in summer compared to other seasons. Primary ACLR conducted in outpatient setting increased from 72% in 2002/03 to 97% in 2018/19.

CONCLUSION

The incidence of ACLR is increasing in Alberta, especially among females and among younger cohorts under 20 years of age. This information can help clinicians to provide patient education and policy-makers to design and implement targeted ACL injury prevention programs.

LEVEL OF EVIDENCE

Level III.