Risk factors associated with revision and contralateral anterior cruciate ligament reconstructions in the Kaiser Permanente ACLR registry

Validating the capture rate of revisions by the New Zealand ACL Registry: An analysis of all-cause reoperation following primary ACL reconstruction

PURPOSE

To validate the New Zealand Anterior Cruciate Ligament (ACL) Registry's capture rate of revisions by cross-referencing Registry data with reoperations data recorded by the Accident Compensation Corporation (ACC) and identify risk factors for all-cause reoperation.

METHODS

Primary ACL reconstructions performed between April 2014 and September 2019 were individually matched on a record-by-record basis between the two databases. The ACC database was used to identify patients who underwent a reoperation with manual review of operation notes to identify whether a revision or other procedure was performed. This was combined with the number of revisions separately recorded in the New Zealand ACL Registry, which was used as the denominator value to calculate the Registry's capture rate of revisions. Patient and surgical data recorded in the Registry were analysed to identify independent predictors for all-cause reoperation.

RESULTS

A total of 8046 primary ACL reconstructions were matched between the New Zealand ACL Registry and the ACC databases. The reoperation rate was 8.9% (n = 715) at a mean follow-up of 2.5 years. Meniscal-related procedures were the most common reoperation (n = 299, 3.7%), followed by revision ACL reconstruction (n = 219, 2.7%), arthrofibrosis (n = 185, 2.3%), cartilage (n = 56, 0.7%) and implants (n = 32, 0.4%). The New Zealand ACL Registry captured 96% of revisions. Younger age (hazard ratio [HR] > 1.4, p < 0.001), earlier surgery (HR > 1.3, p = 0.05), concurrent meniscal repair (medial meniscus HR = 1.9, p < 0.001 and lateral meniscus HR = 1.3, p = 0.022) and hamstring tendon autografts (HR = 1.4, p = 0.001) were associated with a higher risk of reoperation.

CONCLUSION

The New Zealand ACL Registry captured 96% of revisions. Risk factors for all-cause reoperation included younger age, earlier surgery, meniscal repair and hamstring tendon autografts.

LEVEL OF EVIDENCE

Level III.

Factors associated with increased 30-day re-operation risk in anterior cruciate ligament reconstruction

BACKGROUND

Revision surgery following isolated anterior cruciate ligament reconstruction (ACLR) has often focused on mid- to long-term revisions due to re-rupture, while short-term 30-day revision is a rare, but underappreciated entity. This study aims to characterize incidence and risk factors for reoperations following isolated ACLR.

METHODS

This is a retrospective case-control analysis of the American College of Surgeons National Surgical Quality Improvement Program Database (NSQIP) database from 2005 to 2017. Current Procedural Terminology codes were used to identify elective isolated ACLR patients. Patients undergoing reoperations were analyzed using bivariate analysis against their respective perioperative variables. Multivariate stepwise logistic regression was used to identify independent risk factors for reoperations after ACLR.

RESULTS

12,790 patients were included in the study. 37.0% of patients were female. Mean age was 32.2+/-10.7 years and mean body mass index (BMI) was 27.8+/-6.5 kg/m2, with 28.9% of patients with BMI > 30. The most frequently reported reason for reoperation based on CPT and ICD-9/10 codes was postoperative infection (0.5%). Overall reoperation rate was approximately 0.5%. Multivariate analysis identified operative time >1.5 h (OR 2.6 [95% CI; 1.5-4.4]), dependent functional status (OR 14.0 [1.4-141.6]), and adjunctive anesthesia (OR 2.4 [95% CI; 1.1-5.0]) as independent risk factors for reoperation. Female sex was a protective factor against reoperations (OR 0.6 [0.3-0.98]).

CONCLUSION

Primary, isolated ACLR is associated with extremely low rates of short-term reoperations. Operative time >1.5 h, dependent functional status, and adjunctive anesthesia were independent risk factors for reoperation and female sex was a protective factor against reoperation.

LEVEL OF EVIDENCE

Level III. Retrospective cohort study.

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.

A new neural network model that detects graft ruptures and contralateral anterior cruciate ligament injuries

PURPOSE

The purpose of this study was to develop a neural network model for predicting second anterior cruciate ligament (ACL) injury risk following ACL reconstruction using patient features from medical records.

METHODS

Of 486 consecutive patients who underwent primary unilateral ACL reconstruction, 386 patients (198 women, 188 men) with a mean age of 25.1 ± 11.6 years were included in this study. Fifty-eight features, including demographic data, surgical, preoperative and postoperative data, were retrospectively collected from medical records, and features with an incidence of less than 5% were excluded. Finally, 14 features were used for the analysis. The multilayer perceptron was composed of four hidden layers with a rectified linear unit as activation and was trained to maximise the area under the receiver-operating characteristic curve (auROC). Subsequently, validation was carried out through a rigorous threefold cross-validation process. To ascertain the most efficacious combination of features with the highest auROC, a single feature with the least impact on auROC maximisation was systematically eliminated from the comprehensive variable set, ultimately resulting in the retention of a mere two variables.

RESULTS

The median follow-up period was 50.5 (24-142) months. Fifty-seven knees had a second ACL injury, with a graft rupture rate of 7.7% and a contralateral injury rate of 6.9%. The maximum auROC for predicting graft rupture was 0.81 with two features: young age and hamstring graft. Meanwhile, the maximum auROC for predicting contralateral ACL injury was 0.74 with seven features, including young age, presence of medial meniscus tear, small body mass index, hamstring graft, female sex and medial meniscus repair or treatment.

CONCLUSION

A neural network model with patient features from medical records detected graft ruptures and contralateral ACL injuries with acceptable accuracy. This model can serve as a new, useful tool in clinical practice to inform decisions about ACL reconstruction and retuning to sports postoperatively.

LEVEL OF EVIDENCE

Level IV.

The Value of Ultrasound Diagnostic Imaging of Anterior Crucial Ligament Tears Verified Using Experimental and Arthroscopic Investigations

This study investigates the potential of the ultrasound imaging technique in the assessment of Anterior Cruciate Ligament (ACL) pathologies by standardizing the examination process. We focused on four key ultrasound parameters: the inclination of the ACL; swelling or scarring at the ACL's proximal attachment to the lateral femoral condyle; swelling or scarring of the ACL/posterior cruciate ligament (PCL) compartment complex with accompanying morphological changes in the posterior joint capsule; and dynamic instability, categorized into three ranges-0-2 mm, 3-4 mm, and ≥5 mm. The study group consisted of 25 patients with an ACL injury and 25 controls. All four tested parameters were found more frequently in the study group compared to the control (p < 0.0001). Our findings suggest that this standardized approach significantly augments the diagnostic capabilities of ultrasound, complementing clinical evaluation and magnetic resonance imaging (MRI) findings. The meticulous assessment of these parameters proved crucial in identifying subtle ACL pathologies, which might otherwise be missed in conventional imaging modalities. Notably, the quantification of dynamic instability and the evaluation of morphological changes were instrumental in early detection of ACL injuries, thereby facilitating more precise and effective treatment planning. This study underscores the importance of a standardized ultrasound protocol in the accurate diagnosis and management of ACL injuries, proposing a more comprehensive diagnostic tool for clinicians in the field of sports medicine and orthopedics.

Risk Factors for Ipsilateral Versus Contralateral Reinjury After ACL Reconstruction in Athletes: A Systematic Review and Meta-analysis

Background

Anterior cruciate ligament (ACL) reinjury after ACL reconstruction (ACLR) can occur on the ipsilateral or contralateral side. Limited evidence exists regarding the difference between the incidence of reinjury to either knee, which is important in developing interventions to prevent ACL reinjury.

Purpose

To compare the reinjury rate of the ACL on the ipsilateral side versus the contralateral side in athletes after ACLR and investigate the risk factors that may cause different reinjury rates between the sides.

Study Design

Systematic review; Level of evidence, 4.

Methods

A systematic review was performed based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies that involved ACL reinjury in athletes after ACLR were reviewed. Considering several risk factors, including age and sex, a comparison of ACL reinjury incidence on the ipsilateral and contralateral sides was performed using a meta-analysis.

Results

Of the 17 selected studies, 3 were found to be at high risk of bias, and thus, 14 (n = 3424 participants) studies were included in the meta-analysis. In this athletic population, the contralateral ACL had a significantly higher rupture rate than the ipsilateral graft (risk ratio [RR], 1.41; P < .0001). Female athletes were found to have a greater risk of ACL reinjury on the contralateral versus the ipsilateral side (RR, 1.65; P = .0005), but different results were found in male athletes. (RR, 0.81; P = .21). There was no statistical difference in the incidence rate of ACL reinjury to either side in adolescent athletes (RR, 1.15; P = .28).

Conclusion

The contralateral ACL was more vulnerable to reinjury than the ipsilateral side in athletes after ACLR. Female athletes were more likely to reinjure their contralateral native ACL, while the same trend was not found in their male counterparts. The reinjury rate was comparable in both knees in adolescent athletes.

Comparison of Knee Pain and Difficulty With Kneeling Between Patellar Tendon and Hamstring Tendon Autografts After Anterior Cruciate Ligament Reconstruction: A Study From the New Zealand ACL Registry

BACKGROUND

The bone-patellar tendon-bone (BTB) autograft is associated with difficulty with kneeling after anterior cruciate ligament (ACL) reconstruction; however, it is unclear whether it results in a more painful or symptomatic knee compared with the hamstring tendon autograft.

PURPOSE

To identify the rate and risk factors for knee pain and difficulty with kneeling after ACL reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Primary ACL reconstruction procedures prospectively recorded in the New Zealand ACL Registry from April 2014 to May 2021 were analyzed. The Knee injury and Osteoarthritis Outcome Score (KOOS) was used to identify patients reporting consequential knee pain (CKP), defined as a KOOS Pain subscore of ≤72 points, and severe kneeling difficulty (SKD), defined as a self-report of "severe" or "extreme" difficulty with kneeling. Absolute values of the KOOS Pain and Symptoms subscales were also compared.

RESULTS

A total of 10,999 patients were analyzed. At 2-year follow-up, 9.3% (420/4492) reported CKP, and 12.0% (537/4471) reported SKD. The most important predictor of CKP at 2-year follow-up was having significant pain before surgery (adjusted odds ratio, 4.10; P < .001). The most important predictor of SKD at 2-year follow-up was the use of a BTB autograft rather than a hamstring tendon autograft (21.3% vs 9.4%, respectively; adjusted odds ratio, 3.12; P < .001). There was no difference between the BTB and hamstring tendon grafts in terms of CKP (9.9% vs 9.2%, respectively; P = .494) or in absolute values of the KOOS Pain (mean, 88.7 vs 89.0, respectively; P = .37) and KOOS Symptoms (mean, 82.5 vs 82.1, respectively; P = .49) subscales.

CONCLUSION

At 2-year follow-up after primary ACL reconstruction, 9.3% of patients reported CKP, and 12.0% reported SKD. The BTB autograft was associated with difficulty with kneeling, but it did not result in a more painful or symptomatic knee compared with the hamstring tendon autograft.

Anterior Cruciate Ligament Tears in the Adolescent Population: Injury Demographics and Risk of Reinjury Among High School Athletes

BACKGROUND

The incidence of anterior cruciate ligament (ACL) injuries is increasing among the adolescent population with a peak occurring in the high school age range.

PURPOSE

To characterize recent epidemiologic trends of ACL injuries, ACL reconstruction (ACLR), and retear rates in high school adolescents based on age, participating sport, and mechanism of injury.

STUDY DESIGN

Retrospective case series.

METHODS

A prospectively maintained institutional database was retrospectively reviewed for all patients 18 or younger who underwent primary ACLR between 2015 and 2020. Odds ratios were calculated for baseline patient characteristics and their association with risk of retear. Multivariate regression analysis was also performed to identify the relationship between retear and specific categorical variables.

RESULTS

A total of 482 patients were included, with a mean follow-up time of 13.0 ± 11.8 months. Patients were an average age of 16.1 ± 1.3 years old (range: 13 to 18 y). Initial presentation of ACL injuries in high school athletes often occurred at 16 years old regardless of the sport played. Based on age, high school freshmen and seniors are found to have an increased risk of ACL retear. One hundred three patients (21.6%) completed at least 2 or more years of follow-up after ACLR. Of these patients, 38.8% received a bone-tendon-bone (BTB) autograft, 36.9% hamstring autograft, 14.6% quadriceps tendon autograft, and 3.9% received hamstring allograft or other graft (eg, tibialis anterior and BTB allograft), respectively. There were 25 ipsilateral ACL retears that occurred in the patient cohort (5.2%). Thirteen (52%) of retears were females. Football and soccer were the most common sports played by patients with a retear of the ipsilateral knee (31.8% and 27.3%, respectively). Patients who were 13 to 14 or 18 years old ( P = 0.009 and 0.035, respectively) or who received a tibialis anterior/BTB allograft ( P = 0.002) were found to have increased risk of ACL retear compared with other age groups. When evaluating by sex, female soccer players had a greater risk of retear compared with male soccer players ( P = 0.007). When adjusting for multiple variables, (including age, sex, body mass index, primary reconstruction graft choice, sport, and length of follow-up), the odds of ipsilateral retear in patients who received hamstring autograft ( P = 0.02), sustained a contralateral ACL tear ( P = 0 .04), or a contact injury ( P = 0.01) were increased.

CONCLUSION

Initial presentation of ACL injuries in high school athletes often occurs at 16 years old regardless of the sport played. Based on age, high school freshmen and seniors are found to have an increased risk of ACL retear. However, the overall rate of ACL retear in high school athletes of all ages is low. Patients who underwent ACLR with hamstring tendon autograft had a greater risk of retear compared with other graft types. Female soccer players also had a greater risk of ACL retear. High school athletes must take caution when in the early high school years (underclassman) and more senior years (upperclassman), as susceptibility for ACL retears is elevated.

LEVEL OF EVIDENCE

Level IV.

Fatigue-induced Landing Alterations in ACL Reconstructed Athletes after Return-to-Sport

At the time of return-to-sport, anterior cruciate ligament reconstructed athletes still show altered neuromechanics in their injured leg during single leg hopping tasks. Part of these alterations can be magnified when these athletes are fatigued. So far, little is known whether fatigue-induced landing alterations persist after return-to-sport. Therefore, the aim of this study was to evaluate whether these alterations persist in the six months following return-to-sport. Sixteen anterior cruciate ligament reconstructed athletes performed five unilateral hop tasks before and after a fatigue protocol. The hop tasks were executed at three different time points (return-to-sport, 3 and 6 months post-return-to-sport). A 2-by-3 repeated measures ANOVA was performed to evaluate whether fatigue-induced landing alterations persisted 3 and 6 months following return-to-sport. At 6 months following return-to-sport, fatigue still induces a reduction in hamstring medialis activation and an increase in the knee abduction moment during a vertical hop with 90-degree inward rotation. Most fatigue-induced landing alterations present at the time of return-to-sport normalize after resumption of sports activities. However, a larger knee abduction moment in the injured leg after resumption of sports activities can still be observed.

Anterior cruciate ligament injuries in female athletes

The anterior cruciate ligament (ACL) is frequently injured in elite athletes, with females up to eight times more likely to suffer an ACL tear than males. Biomechanical and hormonal factors have been thoroughly investigated; however, there remain unknown factors that need investigation. The mechanism of injury differs between males and females, and anatomical differences contribute significantly to the increased risk in females. Hormonal factors, both endogenous and exogenous, play a role in ACL laxity and may modify the risk of injury. However, data are still limited, and research involving oral contraceptives is potentially associated with methodological and ethical problems. Such characteristics can also influence the outcome after ACL reconstruction, with higher failure rates in females linked to a smaller diameter of the graft, especially in athletes aged < 21 years. The addition of a lateral extra-articular tenodesis can improve the outcomes after ACL reconstruction and reduce the risk of failure, and it should be routinely considered in young elite athletes. Sex-specific environmental differences can also contribute to the increased risk of injury, with more limited access to and availablility of advanced training facilities for female athletes. In addition, football kits are designed for male players, and increased attention should be focused on improving the quality of pitches, as female leagues usually play the day after male leagues. The kit, including boots, the length of studs, and the footballs themselves, should be tailored to the needs and body shapes of female athletes. Specific physiotherapy programmes and training protocols have yielded remarkable results in reducing the risk of injury, and these should be extended to school-age athletes. Finally, psychological factors should not be overlooked, with females' greater fear of re-injury and lack of confidence in their knee compromising their return to sport after ACL injury. Both intrinsic and extrinsic factors should be recognized and addressed to optimize the training programmes which are designed to prevent injury, and improve our understanding of these injuries.

Risk Factors for Revision or Rerupture After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis

BACKGROUND

The rerupture or need for revision after anterior cruciate ligament reconstruction (ACLR) is a serious complication. Preventive strategies that target the early identification of risk factors are important to reduce the incidence of additional surgery.

PURPOSE

To perform a systematic review and meta-analysis to investigate risk factors for revision or rerupture after ACLR.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

Literature searches were performed in PubMed, Embase, and Web of Science from database inception to November 2021 and updated in January 2022. Quantitative, original studies reporting potential adjusted risk factors were included. Odds ratios (ORs) were calculated for potential risk factors.

RESULTS

A total of 71 studies across 13 countries with a total sample size of 629,120 met the inclusion criteria. Fifteen factors were associated with an increase in the risk of revision or rerupture after ACLR: male sex (OR, 1.27; 95% CI, 1.14-1.41), younger age (OR, 1.07; 95% CI, 1.05-1.08), lower body mass index (BMI) (OR, 1.03; 95% CI, 1.00-1.06), family history (OR, 2.47; 95% CI, 1.50-4.08), White race (OR, 1.32; 95% CI, 1.08-1.60), higher posterolateral tibial slope (OR, 1.15; 95% CI, 1.05-1.26), preoperative high-grade anterior knee laxity (OR, 2.30; 95% CI, 1.46-3.64), higher baseline Marx activity level (OR, 1.07; 95% CI, 1.02-1.13), return to a high activity level/sport (OR, 2.03; 95% CI, 1.15-3.57), an ACLR within less than a year after injury (OR, 2.05; 95% CI, 1.81-2.32), a concomitant medial collateral ligament (MCL) injury (OR, 1.62; 95% CI, 1.31-2.00), an anteromedial portal or transportal technique (OR, 1.36; 95% CI, 1.22-1.51), hamstring tendon (HT) autografts (vs bone-patellar tendon-bone [BPTB] autografts) (OR, 1.60; 95% CI, 1.40-1.82), allografts (OR, 2.63; 95% CI, 1.65-4.19), and smaller graft diameter (OR, 1.21; 95% CI, 1.05-1.38). The other factors failed to show an association with an increased risk of revision or rerupture after ACLR.

CONCLUSION

Male sex, younger age, lower BMI, family history, White race, higher posterolateral tibial slope, preoperative high-grade anterior knee laxity, higher baseline Marx activity level, return to a high activity level/sport, an ACLR within less than a year from injury, a concomitant MCL injury, an anteromedial portal or transportal technique, HT autografts (vs BPTB autografts), allografts, and smaller graft diameter may increase the risk of revision or rerupture after ACLR. Raising awareness and implementing effective preventions/interventions for risk factors are priorities for clinical practitioners to reduce the incidence of revision or rerupture after ACLR.

Long-term results after anterior cruciate ligament reconstruction using patellar tendon versus hamstring tendon autograft with a minimum follow-up of 10 years-a systematic review

INTRODUCTION

A lot of research addresses superiority of the two commonly used autografts bone-patellar tendon-bone (BPTB) and hamstring tendon for anterior cruciate ligament (ACL) reconstruction, without getting to consensus. While there are numerous studies and reviews on short- to mid-term follow-up, not much literature is available on long-term follow-up. As patients suffering ACL injuries are often of young age and high athletic activity, it is crucial to have the best evidence possible for graft choice to minimize consequences, like osteoarthritis later on.

MATERIALS AND METHODS

A search of the online databases, PubMed and Embase, was carried out last on 31st March 2022 for studies comparing BPTB and hamstring tendon (HT) autografts for ACL reconstruction in human patients with a minimum follow-up of 10 years. The methodological quality of each study has been evaluated using the modified Coleman Methodology Score. Results on the three variables patient-oriented outcomes, clinical testing and measurements and radiographic outcomes were gathered and are presented in this review.

RESULTS

Of 1299 records found, nine studies with a total of 1833 patients were identified and included in this systematic review. The methodological quality of the studies ranged from a Coleman Score of 63-88. Many studies reported no or only few statistically significant differences. Significant results in favour of BPTB were found for activity levels and for instrumented laxity testing with the KT-1000 arthrometer. Better outcomes for HT were found in IKDC-SKF, the KOOS, donor site morbidity, pivot shift test, radiographic osteoarthritis (IKDC C or D) and contralateral ACL rupture. No studies presented significant differences in terms of Lysholm Score or Tegner Activity Score, Lachman test, single-legged hop test, deficits in range of motion, osteoarthritis using the Kellgren and Lawrence classification or graft rupture.

CONCLUSION

We cannot recommend one graft to be superior, since both grafts show disadvantages in the long-term follow-up. Considering the limitation of our systematic review of no quantitative analysis, we cannot draw further conclusions from the many insignificant results presented by individual studies.

LEVEL OF EVIDENCE

IV.

Two-Dimensional Magnetic Resonance Imaging in Preparation for Autograft Anterior Cruciate Ligament Reconstruction Demonstrates Quadriceps Tendon Is Thicker Than Patellar Tendon

Purpose

The purpose of this study was to assess patellar tendon (PT) and quadriceps tendon (QT) thickness on preoperative magnetic resonance imaging (MRI), in both the sagittal and axial planes, at multiple points along each tendon, and to correlate these findings to anthropometric patient data before anterior cruciate ligament (ACL) surgery.

Methods

Patients who underwent PT or QT autograft ACL reconstruction between 2020 and 2022 and who had preoperative MRIs with adequate visualization of the proximal QT and distal PT were retrospectively identified. Patient demographics were recorded (age, height, weight, sex, injury side). Preoperative MRI measurements were performed by 3 independent examiners using standardized protocol. Preoperative MRI measurements were the QT anterior-posterior (AP) thickness at 1, 2, and 4 cm from the proximal patella on axial and sagittal MRI images at the central aspect of the tendon, as well as PT AP thickness at 1, 2, and 4 cm from the distal patella on axial and sagittal MRI images at the central aspect of the tendon.

Results

Forty-one patients (21 females, 20 males) were evaluated, with a mean age of 33.4 years. The quadriceps tendon was significantly thicker than the patellar tendon at all measured locations (P < .0001) with average QT versus PT thickness (in mm) at each level sagittal 1 cm (7.13 vs 4.35), sagittal 2 cm (7.41 vs 4.44), sagittal 4 cm (7.26 vs 4.81), axial 1 cm (7.35 vs 4.50), axial 2 cm (7.63 vs 4.47), axial 4 cm (7.46 vs 4.62), respectively. There were no significant correlations between tendon size and patient body mass index.

Conclusions

The quadriceps tendon is significantly thicker than the patellar tendon at 1, 2, and 4 cm from the patella in both males and females based on preoperative MRI before ACL surgery.

Clinical relevance

Investigating the thickness of the tendons available for autograft harvest before surgery will give us a better understanding of tendon anatomy in the setting of ACL reconstruction.

Graft failure and revision rate after ACL repair with dynamic intraligamentary stabilization. One-year results of a prospective case series of 155 patients

PURPOSE

The aim of this study was to assess graft failure, revision rate, and functional outcomes after treatment of acute ACL rupture with dynamic intraligamentary stabilization (DIS) Ligamys device one year post surgery. Additionally, differences in functional outcome between patients with and without anteroposterior laxity were assessed. It was hypothesized that the failure rate of DIS was non-inferior to that of previously reported ACL reconstruction (10%).

METHODS

In this prospectively designed multicenter study, including patients with an acute ACL rupture, DIS was performed within 21 days after rupture. Primary outcome was failure of the graft at 1 year post surgery, defined as 1) re-rupture of the graft, 2) revision of DIS, or 3) a > 3 mm side-to-side difference in anterior tibial translation compared to the non-operated knee (∆ATT), measured by the KT1000 device. Additional analysis was performed using a 5 mm threshold. The subjective International Knee Documentation Committee Score (IKDC) and Numerical Rating Scales (NRS) for pain and confidence were used to evaluate functional outcome.

RESULTS

A total of 155 patients were included with a mean age at surgery of 27.8 years (SD 9.4). The mean interval from rupture to DIS was 16.4 days (SD 5.2). At a median follow-up of 13 months (IQR 12-18) the failure rate of the graft was 30.2% (95%CI:22.0-39.4); 11 patients (7%) required secondary reconstructive surgery and of the 105 patients who attended ATT measurement, 24 patients (23%) had an ∆ATT > 3 mm. Secondary analysis, based on a 5 mm threshold, revealed a failure rate of 22.4% (95%CI: 15.2; 31.1). A total of 39 patients (25%) reported at least one complication, comprising mainly arthrofibrosis, traumatic re-rupture and pain. In these patients, removal of the monoblock was performed in 21 cases (13.5%). At follow-up no significant differences in functional outcomes between patients with ∆ATT > 3 mm and stable ATT were observed.

CONCLUSION

This prospective multicenter study found a high failure rate at one year follow-up of 30% (7% revision surgery and 23% > 3 mm side-to-side difference in anterior tibial translation) in patients treated by primary repair of the ACL with DIS, and did therefore not demonstrate non-inferiority to ACL reconstruction. For patients who did not require secondary reconstructive surgery, this study found good functional outcomes, also in case of persistent anteroposterior knee laxity (∆ATT > 3 mm).

LEVEL OF EVIDENCE

Level IV.

Comparison of Psychological Readiness to Return to Sport After Primary Versus Revision Anterior Cruciate Ligament Reconstruction

Background

Rates of return to preinjury level of play after anterior cruciate ligament (ACL) reconstruction (ACLR) remain unsatisfactory, particularly for patients who undergo revision surgery. Psychological readiness is associated with successful return to sport (RTS) and self-perceived preinjury sport performance.

Purpose

To compare psychological readiness at RTS between patients who underwent revision ACL autograft reconstruction and matched controls who underwent primary ACL autograft reconstruction.

Study Design

Cohort study; Level of evidence, 3.

Methods

Data were gathered using a single orthopaedic surgeon database of patients who underwent ACLR between 2015 and 2018. Patients who underwent revision ACLR and met the study criteria (N = 92) were matched by age, sex, graft type, and rehabilitation protocol to a control group of patients who underwent primary ACLR (n = 92). Functional assessment at release to play was examined using passive knee range of motion, single-leg squat, and single-leg hop testing. Self-reported outcomes included the International Knee Documentation Committee subjective function survey and the ACL-Return to Sport after Injury (ACL-RSI) psychological readiness scale. Time to release to play was recorded as the number of months needed to reach a ≥90% limb symmetry index from the date of the index ACLR. Data were assessed for normality using the Shapiro-Wilk test, and univariate general linear models were utilized with an alpha level of .05.

Results

The overall mean patient age was 29.9 ± 10 years, and 40% of patients were women. No significant differences between groups were noted in any of the baseline patient characteristics or surgical findings. At RTS, the mean ACL-RSI score was significantly lower in the revision surgery group (77.4 ± 19.4 vs 85.3 ± 17.4; P = .011). In addition, the revision surgery group returned to play significantly later than the primary surgery group (9.4 ± 2 vs 8.1 ± 1.3 months, respectively; P < .001).

Conclusion

When compared with primary ACL autograft reconstruction, revision reconstruction patients exhibited lower psychological readiness scores and a longer time to meet the objective criteria for RTS.

Registration

NCT03704376 (ClinicalTrials.gov identifier).

Current trends in graft choice for primary anterior cruciate ligament reconstruction - part II: In-vivo kinematics, patient reported outcomes, re-rupture rates, strength recovery, return to sports and complications

Postoperative patient satisfaction after anterior cruciate ligament reconstruction (ACL-R) is influenced mainly by the degree of pain, the need for reoperation, and functional performance in daily activities and sports. Graft choice has shown to have an influence on postoperative outcomes after ACL-R. While patient reported outcomes measurements do not differ between graft options, evidence shows that normal knee kinematics is not fully restored after ACL-R with an increase in postoperative anterior tibial translation (ATT). Postoperative graft rupture rates seem to favor bone-patella-tendon-bone (BPTB) and quadriceps tendon (QT) autografts over HT or allografts. While return to sports rates seem comparable between different graft types, postoperative extensor strength is reduced in patients with BPTB and QT whereas flexion strength is weakened in patients with HT. Postoperative donor site morbidity is highest in BPTB but comparable between HT and QT. With all graft options having advantages and drawbacks, graft choice must be individualized and chosen in accordance with the patient.

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.

Return to Sports: A Risky Business? A Systematic Review with Meta-Analysis of Risk Factors for Graft Rupture Following ACL Reconstruction

BACKGROUND

The risk of sustaining a graft rupture after anterior cruciate ligament reconstruction (ACLR) is high. Contributing risk factors are, however, still not clearly identified.

OBJECTIVE

The aim of this systematic review was to identify and quantify risk factors for graft rupture after ACLR.

METHODS

A systematic review with meta-analysis (PROSPERO CRD42020140129) based on PRISMA guidelines was performed. MEDLINE, CINAHL and EMBASE were searched from inception to September 2021. Prospective and retrospective studies addressing risk factors for graft rupture after ACLR in males/females of all ages were considered. Meta-analyses using a random effect model (effect measure: odds ratio [OR] with 95% confidence interval [CI]) were performed. The GRADE tool was used to assess evidence quality.

RESULTS

Following full-text screening of 310 relevant papers, 117 were eventually included, incorporating up to 133,000 individuals in each meta-analysis. Higher Tegner activity level (≥ 7 vs < 7) at primary injury (OR 3.91, 95% CI 1.69-9.04), increased tibial slope (degrees) (OR 2.21, 95% CI 1.26-3.86), lower psychological readiness to return to sport (RTS) (OR 2.18, 95% CI 1.32-3.61), early surgery (< 12 vs ≥ 12 months) (OR 1.87, 95% CI 1.58-2.22), RTS (pre-injury level) (OR 1.87, 95% CI 1.21-2.91) and family history of ACL injury (OR 1.76, 95% CI 1.34-2.31) were all associated with increased odds of graft rupture. Higher age (OR 0.47, 95% CI 0.39-0.59), female sex (OR 0.88, 95% CI 0.79-0.98), fewer self-reported knee symptoms pre-reconstruction (OR 0.81, 95% CI 0.69-0.95) and concomitant cartilage injuries (OR 0.70, 95% CI 0.62-0.79) instead decreased the odds. Meta-analysis revealed no association between body mass index, smoking, joint laxity, RTS time, knee kinematics, muscle strength or hop performance and graft rupture.

CONCLUSION

Conspicuous risk factors for graft rupture were mainly sports and hereditary related. Few studies investigated function-related modifiable factors or included sports exposure data.

Psychological Patient-reported Outcomes Cannot Predict a Second Anterior Cruciate Ligament Injury in Patients who Return to Sports after an Anterior Cruciate Ligament Reconstruction

Background

Psychological patient-reported outcomes (PROs) are recommended for use in test batteries to aid in decision-making, regarding whether patients are well prepared to return to sports (RTS) after anterior cruciate ligament (ACL) reconstruction. However, the values that should be regarded as "pass" or "fail" are still unclear.

Purpose

This study aimed to identify cut-off values for three commonly used psychological PROs that could differentiate patients who suffer a second ACL injury from patients who do not within two years of RTS in patients after ACL reconstruction with respect to recovery of symmetrical quadriceps strength.

Study design

Diagnostic/prognostic study.

Methods

Demographic data, isokinetic strength test data for quadriceps, as well as results for the ACL-Return to Sport after Injury scale (ACL-RSI), Knee Injury and Osteoarthritis Outcome Score (KOOS) Quality of Life, and Function in Sport and Recreation sub-scales, and the 18-item version of the Knee Self-Efficacy Scale (K-SES18) were extracted from a registry. Receiver operating characteristic (ROC) curves were calculated for each PRO. Accuracy of the cut-offs was presented with two summary measures for the ROC: the area under the curve (AUC) and Youden index.

Results

In total, 641 (355 men, 61%) patients (24.8 [SD 7.6] year old at ACL reconstruction) were included. The cut-off values were not able to differentiate patients who suffered a second ACL injury up to 24 months after RTS and ACL reconstruction from patients who did not. Additionally, achieving symmetrical quadriceps strength did not improve the cut-off psychometric properties.

Conclusion

Since cut-off values could not differentiate between patients who suffered a second ACL injury and those who did not, clinicians should not rely only on cut-off values or a single PRO of those analyzed in this study when making decisions on which patients are at risk of experiencing a second ACL injury when returning to sports after ACL reconstruction.

Level of Evidence

Level 3.

Risk Factors for Anterior Cruciate Ligament Graft Failure in Professional Athletes: An Analysis of 342 Patients With a Mean Follow-up of 100 Months From the SANTI Study Group

BACKGROUND

Anterior cruciate ligament (ACL) injuries are among the most common knee injuries sustained in elite sport, and athletes generally undergo ACL reconstruction (ACLR) to facilitate their return to sport. ACL graft rupture is a career-threatening event for elite athletes.

PURPOSE/HYPOTHESIS

The purpose of this study was to determine the risk factors for graft failure in professional athletes undergoing ACLR. It was hypothesized that athletes who underwent combined ACLR with a lateral extra-articular procedure (LEAP) would experience significantly lower rates of graft rupture in comparison with those who underwent isolated ACLR.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Professional athletes who underwent primary ACLR with a minimum follow-up of 2 years were identified from the Santy database. Patients were excluded if they underwent major concomitant procedures, including multiligament reconstruction surgery or osteotomy. Further ipsilateral knee injury, contralateral knee injury, and any other reoperations or complications after the index procedure were identified by interrogation of the database and review of the medical notes.

RESULTS

A total of 342 athletes with a mean follow-up of 100.2 ± 51.9 months (range, 24-215 months) were analyzed. Graft failures totaling 31 (9.1%) were reported, requiring revision surgery because of symptomatic instability. The rate of graft failure was significantly higher when ACLR was not combined with a LEAP (15.5% vs 6.0%; P = .0105) and in athletes aged 21 years or younger (13.8% vs 6.6%; P = .0290). A multivariate analysis was performed using the Cox model and demonstrated that athletes undergoing an isolated ACLR were at >2-fold risk of ACL graft rupture (hazard ratio [HR], 2.678 [1.173; 4.837], P = .0164) when compared with those undergoing a combined ACLR with a LEAP. Additionally, athletes aged ≤21 years were also at >2-fold risk of graft failure (HR, 2.381 [1.313; 5.463]; P = .0068) than those aged >21 years. Sex, sport, and graft type were not found to be significant risk factors for graft failure.

CONCLUSION

Professional athletes undergoing isolated ACLR and aged ≤21 years are at >2-fold greater risk of graft failure. Orthopaedic surgeons treating elite athletes should combine an ACLR with a LEAP to improve ACL graft survivorship.

'I was young, I wanted to return to sport, and re-ruptured my ACL' - young active female patients' voices on the experience of sustaining an ACL re-rupture, a qualitative study

Background

Despite anterior cruciate ligament (ACL) re-ruptures being common, research on patient experiences after knee trauma has primarily focused on the time after primary ACL reconstruction. Integrating qualitative research and patient experiences can facilitate researchers and clinicians in understanding the burden of an ACL re-rupture. The aim of the study was to explore the experiences of an ACL re-rupture journey in young active females aiming to return to knee-strenuous sports after primary ACL reconstruction.

Method

Fifteen young (19[range 16–23] years old) active females who suffered an ACL re-rupture were interviewed with semi-structured interviews. Qualitative content analysis using deductive approach based on Wiese-Bjornstal’s ‘integrated model of response to sport injury’ was used.

Results

The results are presented in two timelines 1) from first ACL injury to ACL re-rupture, and 2) from ACL re-rupture to present day, and further stratified according to the domains of the ‘integrated model of psychological response to injury’. Results in the first timeline are summarised into seven categories: Finding hope for the journey; Accepting my ACL injury; I succeeded; What matters now? Who am I?; Where will this end? What is going to happen? In the second timeline, eight categories were identified: Fighting spirit; A helping hand; Working hard; I am a new me; I am destroyed; Loneliness; Painful changes; and, I could have made it to the pro´s.

Conclusion

Young active females who suffered an ACL re-rupture did not express any positive experience following their first ACL injury, however, in contrast, expressed positive experiences and personal growth after going through the ACL re-rupture journey, characterized by a lot of struggling, and ultimately led to the experience of becoming a new, stronger person.

Optimal Graft Choice in Athletic Patients with Anterior Cruciate Ligament Injuries: Review and Clinical Insights

Anterior cruciate ligament (ACL) rupture is a common sporting-related knee injury with a potentially detrimental impact on the athlete’s career, yet there is no formal consensus on the optimal graft choice for reconstructing the ruptured ACL in this specific population. Options for reconstruction include autograft, allograft, and artificial grafts. However, each has associated failure risk and donor site morbidity. Our operational definition of the athlete is a skeletally mature individual participating in high level activity with the expectation to return to pre-injury level of activity. The athlete has unique injury characteristics, post-operative expectations, and graft demands that differ to the general population. Long-term outcomes are of particular importance given on-going mechanical demands on the reconstructed knee. Therefore, the purpose of this review is to consolidate current literature on the various ACL reconstruction graft options, with a focus on the optimal graft for returning the athlete to activity with the lowest rate of re-injury.

Notchplasty is associated with decreased risk of anterior cruciate ligament graft revision

PURPOSE

Despite influencing knee biomechanics and outcomes, the use of notchplasty at time of anterior cruciate ligament reconstruction (ACLR) has not been evaluated with regards to risk of secondary injury and revision. This study evaluates this association.

METHODS

42 patients (21.7-years, IQR = 19.0-27.5) that underwent primary then revision ACLR at a single institution were contrasted with a case matched control group of patients with grafts that did not fail. Patients were propensity score matched in a 1:2 ratio by age, gender, and date of index procedure. Post-hoc statistical correction was made for post-index procedure sports participation level.

RESULTS

Notchplasty was performed in 2 of 42 cases that went on to revision, and in 31 of 84 cases in the control group (p < 0.001). This was associated with reduced rates of revision ACLR (OR = 0.085, 95%CI = 0.019-0.378). A significant difference was seen in the post-ACLR activity level between groups (p = 0.028), with post-hoc testing highlighting those returning to competitive sport to be more likely to require subsequent revision (OR = 9.647, 95%CI = 1.947-47.795). Notchplasty remained significantly associated with (reduced) risk of revision surgery, despite the observed variation in post-ACLR activity (p = 0.001).

CONCLUSION

Individuals whose graft failed following ACLR were significantly less likely to have had notchplasty performed as part of their surgery than a control group who did not suffer graft reinjury. We propose that this may be due to decreased tensioning of the graft as the knee enters dynamic valgus, which may be of great relevance to athletes undergoing ACLR to enable return to sport.

Are 6-Month Functional and Isokinetic Testing Measures Risk Factors for Second Anterior Cruciate Ligament Injuries at Long-T Follow-Up?

INTRODUCTION

 Second anterior cruciate ligament (SACL) injuries are a devastating complication following return to sport (RTS). Appropriate and safe RTS criteria that reduce the risk of SACL injuries are needed. The goal of this study was to investigate the relationship between functional and isokinetic testing at 6 months following primary ACL reconstruction (ACLR) as risk factors for SACL injuries.

METHODS

 Patients with primary ACLR from 1990 to 2010 were identified. Those with 6-month postoperative functional and isokinetic testing and a minimum of 2-year follow-up were included. Functional testing included vertical jump, single-leg hop, and single-leg triple hop. Isokinetic testing included concentric quadriceps and hamstrings (HSs) strength at 60 and 180 degree/s speeds. Statistical analysis evaluated the significance of the various tests between those with and without a secondary tear.

RESULTS

 In total, 344 patients with a mean age of 26.0 ± 9.8 years at an average time of 9.1 ± 3.5 years of follow-up were analyzed. Fifty-nine patients (17%) experienced SACL injuries at an average time of 4.8 years following ACLR with 34 (58%) ipsilateral graft ruptures and 25 (43%) contralateral tears. Several isokinetic measures were significantly different between the NO SACL and the SACL groups: quadriceps 60 degree/s limb symmetry index (LSI) (75 vs. 82% p = 0.01), HS 60 degree/s LSI (92 vs. 97%, p = 0.04), quadriceps 180 degree/s involved/body weight (BW) (41 vs. 47%, p = 0.04), and HS 180 degree/s involved/BW (30 vs. 34%, p = 0.04). Patients with involved limb peak quadriceps torque value greater than 65 or 50% of BW (60 and 180 degree/s) had a 2.2 and 3.1 times higher risk of an SACL injury.

CONCLUSIONS

 Patients with certain elevated isokinetic scores in the injured limb at 6 months after ACLR experienced a higher rate of subsequent ACL injuries than those who had lower peak torque. Although a quantitative only analysis may not be sufficient to determine RTS criteria, clinicians should caution high-performing patients about the risk of subsequent ACL injury.

LEVEL OF EVIDENCE

 Cohort study; 3.

A Systematic Review and Meta-Analysis of Strength Recovery Measured by Isokinetic Dynamometer Technology after Anterior Cruciate Ligament Reconstruction Using Quadriceps Tendon Autografts vs. Hamstring Tendon Autografts or Patellar Tendon Autografts

Background: This systematic review and meta-analysis compared the isokinetic strength of the muscular knee joint between quadriceps tendon autografts (QTAs) and hamstring tendon autografts (HTAs) or patellar tendon autografts (PTAs) after anterior cruciate ligament (ACL) reconstruction by determining the isokinetic angular velocity and follow-up time points. The functional outcomes and knee stability at the same time points were also compared using isokinetic technology. Methods: Two independent reviewers searched the Medline (via PubMed search engine), Scopus, Web of Science and Cochrane Library databases to include full text comparative studies that assessed isokinetic strength test following ACL reconstruction. The DerSimonian and Laird method was used. Results: In total, ten studies were included; seven compared studies QTAs vs. HTAs, and three compared QTAs vs. PTAs. Five studies were included in the meta-analysis. Isokinetic strength data were reported 3, 6, 12 and 24 months after ACL reconstruction. Conclusions: The QTAs showed better and significant results with knee flexion compared with HTAs, similar results to PTAs at 6 and 12 months. While HTAs showed better and significant results with knee extension at 6 months and similar results at 12 months compared to QTAs. Furthermore, a standardized isokinetic strength test must be followed to achieve a more specific conclusion and better clinical comparison among participants.

More anatomic tunnel placement for anterior cruciate ligament reconstruction by surgeons with high volume compared to low volume

PURPOSE

Correct placement of the femoral and tibial tunnels in the anatomic footprint during anterior cruciate ligament reconstruction (ACLR) is paramount for restoring rotatory knee stability. Recent studies have looked at surgeon volume and its outcomes on procedures such as total knee arthroplasty and infection rates, but only few studies have specifically examined tunnel placement after ACLR based on surgeon volume. The purpose of this study was to compare the placement of femoral and tibial tunnels during ACLR between high-volume and low-volume surgeons. It was hypothesized that high-volume surgeons would have more anatomic tunnel placement compared with low-volume surgeons.

METHODS

A retrospective review of all ACLR performed between 2015 and 2019 at an integrated health care system consisting of both academic and community hospitals with 68 orthopaedic surgeons was conducted. Surgeon volume was categorized as less than 35 ACLR per year (low volume) and 35 or more ACLR per year (high volume). Femoral tunnel placement for each patient was determined using an exact strict lateral radiograph (less than 6 mm of offset between the posterior halves of the medial and lateral condyles) taken after the primary ACLR using the quadrant method. The centre of the femoral tunnel was measured in relation to the posterior-anterior (PA) and proximal-distal (PD) dimensions (normal centre of anatomic footprint: PA 25% and PD 29%). Tibial tunnel placement for each patient was determined on the same lateral radiographs by measuring the mid-sagittal tibial diameter and the centre of the tibial attachment area of the ACL from the anterior tibial margin (normal centre of anatomic footprint: 43%). Each lateral radiograph was reviewed by one of two blinded reviewers.

RESULTS

A total of 4500 patients were reviewed, of which 645 patients met all the inclusion/exclusion criteria and were included in the final analysis. There were 228 patients in the low-volume group and 417 patients in the high-volume group. Low-volume surgeons performed a mean of 5 ACLRs per year, whereas surgeons in the high-volume group performed a mean of 40 ACLRs per year. In the PA dimension, the low-volume group had significantly more anterior femoral tunnel placement compared with the high-volume group (32 ± 10% vs 28 ± 9%, p < 0.01). In the PD dimension, the low-volume group had statistically significant more proximal femoral tunnel placement compared to the high-volume group (32 ± 9% vs 35 ± 9%, p < 0.01). For the tibial tunnel, the low-volume group had significantly more posterior tibial tunnel placement compared with the high-volume group (41 ± 10% vs 38 ± 7%, p < 0.01).

CONCLUSION

Low-volume surgeons placed their femoral tunnels significantly more anterior and proximal (high) during ACLR, and placed their tibial tunnels significantly more posterior, compared with high-volume surgeons. Prior research has indicated that anatomic placement of the femoral and tibial tunnels during ACLR leads to improved rotatory knee stability. The findings of this study demonstrate the importance of surgical volume and experience during ACLR.

LEVEL OF EVIDENCE

III.

Revision ACL reconstruction has higher incidence of 30-day hospital readmission, reoperation, and surgical complications relative to primary procedures

PURPOSE

Although there has been substantial improvement in ACL reconstructive surgery, graft failure remains a devastating complication for some patients. Revision procedures are inherently more complex and technically challenging. The purpose of this study is to determine the incidence of short-term complications after these procedures and to compare trends in operative length, relative valuation, and reimbursement after primary versus revision ACL reconstruction.

METHODS

Primary and revision arthroscopic ACL reconstruction cases were identified on the American College of Surgeons' NSQIP database using Current Procedural Terminology (CPT) and International Classification of Diseases (ICD) codes between January 1, 2012 and December 31, 2017. Demographics, patient variables, and surgical variables were compared between primary and revision groups using Chi-squared tests. Logistic regression was used to identify independent risk factors for revision ACL reconstruction. Various 30-day outcome measures were compared between the primary and revision ACL reconstruction groups. Various measures of valuation-including total relative value units (RVU) and reimbursement per minute-were calculated and compared between the two groups.

RESULTS

A total of 8292 patients-8135 primary and 157 revision procedures-were included in the final cohort. Higher ASA scores were associated with revision ACL reconstructions. Patients undergoing revision procedures were less likely to have an ASA score of 1 (p < 0.001) and more likely to have an ASA score of 2 (p = 0.004) or 3 (p = 0.020). Revision ACL reconstruction was associated with higher rates of poor 30-day outcome measures, including unplanned readmission (p = 0.029), reoperation (p = 0.012), return to the OR (p = 0.012), and surgical complications (p = 0.021). The total RVUs and reimbursement for revision procedures were significantly greater than those for primary procedures (p < 0.001). However, when accounting for operative time, the RVU/minute and reimbursement/minute were similar between the two groups (n.s.).

CONCLUSIONS

Relative to primary ACL reconstruction, revision ACL procedures are associated with worse short-term outcomes-including unplanned readmission, reoperation, return to the OR, and surgical complications. A greater ASA score was independently predictive of revision ACL surgery. The current RVU system undervalues revision ACL procedures, considering the increased operative time and complexity of such procedures.

LEVEL OF EVIDENCE

Level III.

Greater Psychological Readiness to Return to Sport, as Well as Greater Present and Future Knee-Related Self-Efficacy, Can Increase the Risk for an Anterior Cruciate Ligament Re-Rupture: A Matched Cohort Study

PURPOSE

To determine the psychological characteristics and strength outcomes of patients who sustained an early anterior cruciate ligament (ACL) re-rupture after their primary ACL reconstruction and cross-sectionally compare them with a matched cohort of patients who did not sustain a reinjury during the first 2 years after primary ACL reconstruction.

METHODS

In this matched cohort study, data for quadriceps and hamstring strength and 3 hop tests and answers to standardized patient-reported outcomes (the Anterior Cruciate Ligament Return to Sport after Injury scale and a short version of the Knee Self-Efficacy Scale) were extracted from a rehabilitation outcome registry. Data for patients suffering a re-rupture were extracted, and patients were matched in terms of sex, age, and activity level with patients not suffering an ACL re-rupture within 2 years of primary reconstruction. The groups were compared 10 weeks and 4, 8, and 12 months after the primary reconstruction.

RESULTS

A total of 36 patients suffering an ACL re-rupture were matched with 108 patients not suffering a re-rupture after ACL reconstruction. Patients who suffered an ACL re-rupture had greater psychological readiness, that is, greater confidence in performance, lesser negative emotions, and lesser risk appraisal, to return to sport (RTS) at 8 months (81.2 vs 67.9 [95% Δconfidence interval {CI} 2.7-23.8) P = .014) and at 12 months (95.2 vs 67.1, (95% ΔCI 14.3-41.8) P ≤ .001), and greater knee-related self-efficacy at 8 months (8.6 vs 8.0 [95% ΔCI 0.1-1.2], P = .021) and 12 months (9.4 vs 8.1, [95% ΔCI 0.3-2.2] P = .012) after primary ACL reconstruction, compared with the matched group.

CONCLUSIONS

A stronger psychological profile, defined by a greater psychological readiness to RTS and knee-related self-efficacy, may be associated with an ACL re-rupture within 2 years of the primary reconstruction.

LEVEL OF EVIDENCE

Matched cohort study, level III.

Suspensory Versus Interference Tibial Fixation of Hamstring Tendon Autografts in Anterior Cruciate Ligament Reconstruction: Results From the New Zealand ACL Registry

BACKGROUND

The hamstring tendon is frequently used to reconstruct the anterior cruciate ligament (ACL), but there is a lack of consensus on the optimal method of fixation. Registry studies have shown that the type of femoral fixation device can influence the risk of revision ACL reconstruction (ACLR), but it is unclear whether the type of tibial fixation has an effect. In New Zealand, over 95% of hamstring tendon grafts are fixed with an adjustable loop suspensory device on the femoral side, with variable usage between suspensory and interference devices, with or without a sheath, on the tibial side.

PURPOSE

To investigate the association between the type of tibial fixation device and the risk of revision ACLR.

STUDY DESIGN

Cohort Study; Level of evidence, 2.

METHODS

Prospective data recorded in the New Zealand ACL Registry were analyzed. Only primary ACLRs performed with a hamstring tendon autograft fixed with a suspensory device on the femoral side were included. A Cox regression survival analysis with adjustment for patient factors was performed to analyze the effects of the type of tibial fixation device, the number of graft strands, and graft diameter on the risk of revision.

RESULTS

A total of 6145 primary ACLRs performed between 2014 and 2019 were analyzed. A total of 59.6% of hamstring tendon autografts were fixed with a suspensory device on the tibial side (n = 3662), 17.6% with an interference screw with a sheath (n = 1079), and 22.8% with an interference screw without a sheath (n = 1404). When compared with suspensory devices, a higher revision risk was observed when using an interference screw with a sheath (adjusted hazard ratio [HR], 2.05; P = .009) and without a sheath (adjusted HR, 1.81; P = .044). The number of graft strands and a graft diameter of ≥8 mm were associated with the rate of revision on the univariate analysis; however, after adjusting for confounding variables on the multivariate analysis, they did not significantly influence the risk of revision.

CONCLUSION

In this study of hamstring tendon autografts fixed with an adjustable loop suspensory device on the femoral side during primary ACLR, the use of an interference screw, with or without a sheath, on the tibial side resulted in a higher revision rate when compared with a suspensory device.

Sex-Specific Outcomes After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis

Background:

Despite the significant difference between men and women in incidence of anterior cruciate ligament (ACL) injuries, there is a paucity of consistent information on the influence of patient sex on outcomes after ACL reconstruction. A previous meta-analysis has demonstrated that female patients have worse outcomes with regard to laxity, revision rate, Lysholm score, and Tegner activity score and are less likely to return to sports (RTS).

Purpose:

To conduct a systematic review and meta-analysis to evaluate and compare sex-specific outcomes after ACL reconstruction.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review was performed using PubMed, PubMed Central, Embase, OVID, and Cochrane databases per PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The following search terms were used: “anterior cruciate ligament reconstruction” OR “ACL reconstruction” OR “anterior cruciate ligament” OR “ACL” AND “gender” OR “sex” OR “male” OR “female” AND “outcome” AND “2015-Present” to gather all relevant articles between 2015 and 2020. A risk-of-bias assessment and quality assessment was conducted on included studies.

Results:

Of 9594 studies initially identified, 20 studies with 35,935 male and 21,455 female patients were included for analysis. The 7 studies reporting International Knee Documentation Committee (IKDC) scores showed that male patients had statistically significantly higher postoperative scores (mean difference, 3.02 [95% CI, 1.19-4.84]; P< .01; I² = 66%), and 7 studies that reported the rate of ACL revision showed there was no significant difference between male and female patients (odds ratio, 0.85 [95% CI, 0.45-1.60]; P = .61; I² = 94%). The 7 studies that reported rates of rerupture showed that males were significantly more likely than females to have a graft rerupture (odds ratio, 1.35 [95% CI, 1.22-1.50]; P < .01; I² = 0%). Male patients reported a higher RTS rate than did their female counterparts (59.82% compared with 42.89%); however, no formal statistical analysis could be done because of the variability in reporting techniques.

Conclusion:

Male and female patients with ACL injuries demonstrated similar outcomes regarding their rates of revision; however, male patients were found to have statistically significantly higher postoperative IKDC scores but at the same time higher rerupture rates. Our findings suggest that sex-based differences in outcomes after ACL reconstruction vary based on which metric is used. These results must be considered when counseling patients with ACL injuries.

Impact of Anterior Cruciate Ligament Injury on European Professional Soccer Players

Background:

The impact of anterior cruciate ligament reconstruction (ACLR) on the performance and career of professional soccer players has not been extensively investigated.

Purpose:

To evaluate in professional European soccer players (1) the ACL injury incidence, (2) the return-to-play (RTP) rate and time after ACLR, (3) career survival and athlete performance in the first 3 postoperative seasons after RTP, (4) factors likely related to different outcomes after ACLR, and (5) any related differences between the top 8 European soccer leagues.

Study Design:

Descriptive epidemiology study.

Methods:

Included were professional soccer players in the top 8 European Soccer leagues (Serie A [Italy], Premier League [England], Ligue 1 [France], LaLiga [Spain], Bundesliga [Germany], Jupiler Pro League [Belgium], Liga NOS [Portugal], and Premier Liga [Russia]) who sustained an ACL injury during seasons 2014 to 2015, 2015 to 2016, and 2016 to 2017. Data were retrieved from publicly available online sources. Outcomes were evaluated based on player age (<25 years, 25-30 years, and >30 years), position (goalkeeper, defender, midfielder, and forward), affected side (dominant vs nondominant), and league.

Results:

Overall, 195 players sustained an ACL injury, for a mean annual ACL injury incidence of 1.42%. The RTP rate was 95%, with a mean RTP time of 248 ± 136 days. Within the third postoperative season, 66 players (36%) competed in a lower level national league, and 25 (13.6%) ended their careers; a significant reduction in the mean minutes played per season was found in all 3 postoperative seasons. Player age correlated significantly with reduction in performance or recovery from an ACL injury. No significant correlation was found between postoperative player performance and affected side, position, league, or time to RTP.

Conclusion:

A substantial ACL injury incidence was found in top European elite soccer players; however, a high RTP rate in a reasonable time was seen after ACLR. Nevertheless, professional soccer players experienced a short-term decline in their performance.

Tear Rates of the Ipsilateral ACL Graft and the Contralateral Native ACL Are Similar following ACL Reconstruction

The aim of the study is to compare the tear rates of ipsilateral anterior cruciate ligament (ACL) grafts and the contralateral native ACL as well as to investigate the correlation of gender, age at time of surgery, and body mass index (BMI) with the occurrence of these injuries. The medical records of 751 patients who underwent ACL reconstruction surgery with follow-up periods of 2 to 7 years were retrospectively analyzed. Survival analyses of ipsilateral ACL grafts and contralateral native ACL were performed. Univariate and multivariate logistic regression analyses were performed to identify risk factors that were associated with these injuries. The tear rates of the ipsilateral ACL graft and contralateral ACL were 5.86 and 6.66%, respectively with no significant difference between groups (p = 0.998). The mean time of tears of the ipsilateral ACL and contralateral ACL was also similar (p = 0.977) at 2.64 and 2.78 years, respectively after surgery. Both the odds of sustaining an ipsilateral ACL graft and contralateral ACL tear were also significantly decreased by 0.10 (p = 0.003) and 0.14 (p = 0.000), respectively, for every 1-year increase in age at which the reconstruction was performed. However, graft type, gender, and BMI were not associated with an increased risk of these injuries. There was no difference between tear rates of ipsilateral ACL graft and contralateral ACL following ACL reconstruction. Patients who undergo ACL reconstruction at a young age are at an increased risk of both ipsilateral graft and contralateral ACL rupture after an ACL reconstruction. Patients who are young and more likely to return to competitive sports should be counselled of the risks and advised to not neglect the rehabilitation of the contralateral knee during the immediate and back to sports period of recovery. This is a Level III, retrospective cohort study.

Social Determinants of Health Influence Access to Care and Outcomes in Patients Undergoing Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To investigate the impact social determinants of health (SDOH) have on accessing orthopaedic treatment after an anterior cruciate ligament injury, as well as patient-reported and surgical outcomes after anterior cruciate ligament reconstruction (ACLR).

METHODS

A systematic search of the PubMed, MEDLINE, Epub Ahead of Print, Embase, and Web of Science databases was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify studies that reported at least 1 SDOH and its effect on patient-reported outcomes or surgical outcomes after anterior cruciate ligament reconstruction. Our search identified 937 studies. After eliminating 273 duplicates, 2 authors screened 664 articles on the basis of title and abstract. After this initial screening, 76 studies were evaluated for data extraction. Studies were categorized based on the social determinant(s) of health reported.

RESULTS

Twenty-two articles published between 2002 and 2020 were included in this study, encompassing 15 retrospective cohort studies, 3 prospective cohort studies, 3 cross-sectional studies, and 1 case-control study from 9 journals across 3 countries. Of these articles, 9 investigated race/ethnicity, 8 investigated insurance status, 4 investigated income, 5 investigated education level, 2 investigated employment status, and 5 investigated socioeconomic status. Reported outcomes included time to treatment, concomitant knee injury, patient-reported outcome measurement scores, postoperative complications, need for additional surgery, and postoperative healthcare utilization.

CONCLUSIONS

Certain SDOH, including black race, Hispanic ethnicity, public health insurance, and lower socioeconomic status contribute to a delay in access to care, which may result in increased severity of concomitant knee injuries encountered at the time of anterior cruciate ligament reconstruction and inferior outcomes.

STUDY DESIGN

Level III, systematic review of level I-III evidence.

Predictors of Graft Failure in Young Active Patients Undergoing Hamstring Autograft Anterior Cruciate Ligament Reconstruction With or Without a Lateral Extra-articular Tenodesis: The Stability Experience

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction (ACLR) has higher failure rates in young active patients returning to sports as compared with older, less active individuals. Augmentation of ACLR with an anterolateral procedure has been shown to reduce failure rates; however, indications for this procedure have yet to be clearly defined.

PURPOSE/HYPOTHESIS

The purpose of this study was to identify predictors of ACL graft failure in high-risk patients and determine key indications for when hamstring ACLR should be augmented by a lateral extra-articular tenodesis (LET). We hypothesized that different preoperative characteristics and surgical variables may be associated with graft failure characterized by asymmetric pivot shift and graft rupture.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data were obtained from the Stability 1 Study, a multicenter randomized controlled trial of young active patients undergoing autologous hamstring ACLR with or without a LET. We performed 2 multivariable logistic regression analyses, with asymmetric pivot shift and graft rupture as the dependent variables. The following were included as predictors: LET, age, sex, graft diameter, tear chronicity, preoperative high-grade knee laxity, preoperative hyperextension on the contralateral side, medial meniscal repair/excision, lateral meniscal repair/excision, posterior tibial slope angle, and return-to-sports exposure time and level.

RESULTS

Of the 618 patients in the Stability 1 Study, 568 with a mean age of 18.8 years (292 female; 51.4%) were included in this analysis. Asymmetric pivot shift occurred in 152 (26.8%) and graft rupture in 43 (7.6%). The addition of a LET (odds ratio [OR], 0.56; 95% CI, 0.37-0.83) and increased graft diameter (OR, 0.62; 95% CI, 0.44-0.87) were significantly associated with lower odds of asymmetric pivot shift. The addition of a LET (OR, 0.40; 95% CI, 0.18-0.91) and older age (OR, 0.83; 95% CI, 0.72-0.96) significantly reduced the odds of graft rupture, while greater tibial slope (OR, 1.15; 95% CI, 1.01-1.32), preoperative high-grade knee laxity (OR, 3.27; 95% CI, 1.45-7.41), and greater exposure time to sport (ie, earlier return to sport) (OR, 1.18; 95% CI, 1.08-1.29) were significantly associated with greater odds of rupture.

CONCLUSION

The addition of a LET and larger graft diameter were significantly associated with reduced odds of asymmetric pivot shift. Adding a LET was protective of graft rupture, while younger age, greater posterior tibial slope, high-grade knee laxity, and earlier return to sport were associated with increased odds of graft rupture. Orthopaedic surgeons should consider supplementing hamstring autograft ACLR with a LET in young active patients with morphological characteristics that make them at high risk of reinjury.

Disparities in ACL Reconstruction: the Influence of Gender and Race on Incidence, Treatment, and Outcomes

PURPOSE OF REVIEW

Anterior cruciate ligament (ACL) rupture is a common injury that has important clinical and economic implications. We aimed to review the literature to identify gender, racial and ethnic disparities in incidence, treatment, and outcomes of ACL injury.

RECENT FINDINGS

Females are at increased risk for ACL injury compared to males. Intrinsic differences such as increased quadriceps angle and increased posterior tibial slope may be contributing factors. Despite lower rates of injury, males undergo ACL reconstruction (ACLR) more frequently. There is conflicting evidence regarding gender differences in graft failure and ACL revision rates, but males demonstrate higher return to sport (RTS) rates. Females report worse functional outcome scores and have worse biomechanical metrics following ACLR. Direct evidence of racial and ethnic disparities is limited, but present. White athletes have greater risk of ACL injury compared to Black athletes. Non-White and Spanish-speaking patients are less likely to undergo ACLR after ACL tear. Black and Hispanic youth have greater surgical delay to ACLR, increased risk for loss to clinical follow-up, and less physical therapy sessions, thereby leading to greater deficits in knee extensor strength during rehabilitation. Hispanic and Black patients also have greater risk for hospital admission after ACLR, though this disparity is improving. Females have higher rates of ACL injury with inconclusive evidence on anatomic predisposition and ACL failure rate differences between genders. Recent literature has suggested inferior RTS and functional outcomes following ACLR in females. Though there is limited and mixed data on incidence and outcome differences between races and ethnic groups, recent studies suggest there may be disparities in those who undergo ACLR and time to treatment.

Age, time from injury to surgery and hop performance after primary ACLR affect the risk of contralateral ACLR

PURPOSE

To evaluate factors affecting the risk of contralateral anterior cruciate ligament reconstruction (ACLR) within 5 years of primary ACLR.

METHODS

Primary ACLRs performed at Capio Artro Clinic, Stockholm, Sweden, during the period 2005-2014, were reviewed. The outcome of the study was the occurrence of contralateral ACLR within 5 years of primary ACLR. Univariable and multivariable logistic regression analyses were employed to identify preoperative [age, gender, body mass index (BMI), time from injury to surgery, pre-injury Tegner activity level], intraoperative [graft type, medial meniscus (MM) and lateral meniscus (LM) resection or repair, cartilage injury] and postoperative [limb symmetry index (LSI) for quadriceps and hamstring strength and single-leg-hop test performance at 6 months] risk factors for contralateral ACLR.

RESULTS

A total of 5393 patients who underwent primary ACLR were included. The incidence of contralateral ACLR within 5 years was 4.7%. Univariable analysis revealed that age ≥ 25 years, BMI ≥ 25 kg/m², time from injury to surgery ≥ 12 months and the presence of a cartilage injury reduced the odds, whereas female gender, pre-injury Tegner activity level ≥ 6, quadriceps and hamstring strength and a single-leg-hop test LSI of ≥ 90% increased the odds of contralateral ACLR. Multivariable analysis showed that the risk of contralateral ACLR was significantly affected only from age ≥ 25 years (OR 0.40; 95% CI 0.28-0.58; P < 0.001), time from injury to surgery ≥ 12 months (OR 0.48; 95% CI 0.30-0.75; P = 0.001) and a single-leg-hop test LSI of ≥ 90% (OR 1.56; 95% CI 1.04-2.34; P = 0.03).

CONCLUSION

Older age (≥ 25 years) and delayed primary ACLR (≥ 12 months) reduced the odds, whereas a symmetrical (LSI ≥ 90%) 6-month single-leg-hop test increased the odds of contralateral ACLR within 5 years of primary ACLR. Knowledge of the factors affecting the risk of contralateral ACLR is important when it comes to the appropriate counselling for primary ACLR. Patients should be advised regarding factors affecting the risk of contralateral ACLR.

LEVEL OF EVIDENCE

Level III.

Optimizing anterior cruciate ligament reconstruction: Individualizing the decision-making process using data from the Kaiser Permanente ACLR Registry: 2018 OREF award paper

Despite years of study, controversy remains regarding the optimal graft for anterior cruciate ligament reconstruction (ACLR), suggesting that a single graft type is not ideal for all patients. A large community based ACLR Registry that collects prospective data is a powerful tool that captures information and can be analyzed to optimize surgery for individual patients. The studies highlighted in this paper were designed to optimize and individualize ACLR surgery and have led to changes in surgeon behavior and improvements in patient outcomes. Kaiser Permanente (KP) is an integrated health care system with 10.6 million members and more than 50 hospitals. Every KP member who undergoes an ACLR is entered into the Registry, and prospectively monitored. The Registry uses a variety of feedback mechanisms to disseminate Registry findings to the ACLRR surgeons and appropriately influence clinical practices and enhance quality of care. Allografts were found to have a 3.0 times higher risk of revision than bone-patellar tendon-bone (BPTB) autografts. Allograft irradiation >1.8 Mrad, chemical graft processing, younger patients, BPTB allograft, and male patients were all associated with a higher risk of revision surgery. By providing feedback to surgeons, overall allograft use has decreased by 27% and allograft use in high-risk patients ≤21 years of age decreased 68%. We have identified factors that influence the outcomes of ACLR. Statement of Clinical Significance: We found that information derived from an ACLR Registry and shared with the participating surgeons directly decreased the use of specific procedures and implants associated with poor outcomes.

A Systematic Approach for Stronger Documentation of Anterior Cruciate Ligament Graft Choice

Numerous studies have focused on determining the optimal choice between the two most used anterior cruciate ligament (ACL) reconstruction autografts. In order to address this matter, we performed a systematic review of every meta-analysis published on the PubMed platform between 2001 and 2020, comparing the functional outcomes, the static stability parameters, as well as the postoperative and long-term complications of the patellar tendon (BPTB) autograft and hamstrings (HT). We retrieved a total of 26 meta-analyses that met our criteria, and the characteristics and outcomes of every meta-analysis, as well as subgroup analysis regarding the type of the study design, number of strands of HT autograft, and fixation method, were extensively recorded. The majority of the meta-analyses showed that there were no significant differences between BPTB and HT in terms of functional outcomes and static stability parameters while HT autografts seem to be superior to BPTB regarding kneeling pain and anterior knee pain. Other outcomes seem to be affected by the number of strands of the HT autograft, the fixation technique, and the type of study design, indicating superiority of the four-strand HT autograft with the use of an extra-cortical button fixation. Overall, there is no clear superiority of BPTB over HT autografts for ACL reconstruction, as both types present similar outcomes in the majority of postoperative parameters. Autograft selection should be individualized according to each patient's needs and more RCTs are warranted in order to reach safer results on the appropriate autograft type.

Higher Rate of Return to Preinjury Activity Levels After Anterior Cruciate Ligament Reconstruction With a Bone-Patellar Tendon-Bone Versus Hamstring Tendon Autograft in High-Activity Patients: Results From the New Zealand ACL Registry

BACKGROUND

In primary anterior cruciate ligament (ACL) reconstruction, a bone-patellar tendon-bone (BTB) autograft is associated with lower ipsilateral failure rates. BTB autografts are associated with a higher rate of contralateral ACL injuries, which some clinicians view as a marker of success of the BTB autograft. However, there is a lack of evidence on whether BTB autografts improve the rate of return to activity and sport.

PURPOSE

To compare the rate of return to preinjury activity levels in high-activity patients after ACL reconstruction with BTB autograft or hamstring tendon autograft.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

In a high-activity cohort of patients recorded between 2014 and 2018 in the New Zealand ACL Registry, prospectively collected data on preinjury and postoperative Marx activity scores were analyzed. The proportion of patients who returned to their preinjury activity levels at 1- and 2-year follow-up was compared between graft types.

RESULTS

Overall, 11.3% (208/1844) of patients returned to their preinjury activity levels at 1-year follow-up, and 15.5% (184/1190) returned at 2-year follow-up. At 1-year follow-up, 17.2% of patients with a BTB autograft returned to their preinjury activity levels compared with 9.3% of patients with a hamstring tendon autograft (adjusted odds ratio, 1.59 [95% CI, 1.16-2.17]; P = .004). At 2-year follow-up, 23.3% of patients with a BTB autograft had returned to their preinjury activity levels compared with 13.3% of patients with a hamstring tendon autograft (adjusted odds ratio, 1.63 [95% CI, 1.14-2.34]; P = .008). Male sex and younger age were associated with a higher rate of return to activity at both follow-up time points.

CONCLUSION

The use of BTB autografts increased the odds of returning to preinjury activity levels at early follow-up. A higher rate of return to activity is a possible explanation for the higher rate of contralateral ACL injuries with the use of BTB autografts.

All-Inside Anterior Cruciate Ligament Reconstruction Using Quadrupled Semitendinosus: Comparable 2-Year Outcomes in Male and Female Patients

PURPOSE

To determine 2-year functional outcomes using an all-inside quadrupled semitendinosus anterior cruciate ligament (ACL) reconstruction technique in male and female patients.

METHODS

A total of 100 patients who underwent quadrupled semitendinosus all-inside hamstring ACL reconstruction by a single surgeon were enrolled. Patient-reported outcome scores collected preoperatively and postoperatively included visual analog scale, Veterans Rand 12-Item Health Survey (VR-12; Physical and Mental), Marx Activity Scale, Knee Injury and Osteoarthritis Outcome Scores (KOOS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

RESULTS

A total of 100 ACL reconstructions comprising 62 female, and 38 male patients were included in this study. Mean graft diameter was 9.4 mm in female and 9.8 mm in male patients (range, 9-11). Outcome scores demonstrated improvement from preoperative to 2-year postoperative respectively: visual analog scale pain 3.18, 1.07, VR-12 physical 36.35, 52.64, VR-12 mental 53.96, 54.65, KOOS pain 59.17, 89.03, KOOS symptoms 52.64, 80.79, KOOS Activities of Daily Living 69.38, 95.4, KOOS Sport 28.97, 81.25, KOOS Quality of Life 27.54, 71.56, WOMAC Pain 71.56, 92.65, WOMAC Stiffness 60.55, 84.13, and WOMAC Function 69.38, 95.4. Marx activity score decreased from baseline (10.98) to 2 years' postoperatively (8.75). At 2 years, patient expectations were met or exceeded with regards to pain (94%), motion and strength (91%), normal function of daily living (95%), and return to sport (79%).

CONCLUSIONS

Anatomic all-inside quadrupled semitendinosus ACL reconstruction improves functional outcomes similarly to previous studies between baseline and clinical follow-up at 1-year and 2-years postoperatively and is comparable in both male and female patients.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Five- and six-strand hamstring grafts consistently produce appropriate graft diameters for anterior cruciate ligament reconstruction

PURPOSE

Hamstring tendon graft diameter less than 8 mm has been correlated with an increased risk of anterior cruciate ligament reconstruction (ACLR) graft failure. The purpose of this study was to measure and compare the diameter of 3-, 4-, 5-, and 6-strand gracilis and semitendinosus (ST) hamstring tendon (HT) ACLR grafts, and to determine if there is a correlation between anthropometric data, HT length, and diameter of the HT ACLR graft.

METHODS

Male patients (n = 78) undergoing primary or revision ACLR with a HT autograft between July 2018 and March 2020 were recruited. Pre-operative anthropometric data was collected. Gracilis and ST tendons were harvested and the length and diameter measured. The following HT graft configurations were prepared in each patient: triple ST; double gracilis + double ST; double gracilis + triple ST; triple gracilis + triple ST. Paired t-tests and Pearson's correlation coefficients were used to assess demographics, anthropometrics, graft diameter, and tendon length. A non-parametric test was used to compare femoral and tibial ACL graft diameters of the 3-, 4-, 5-, and 6-strand HT graft configurations.

RESULTS

For the femoral end, 10%, 19%, 69% and 86% of the patients achieved graft diameters of equal to or greater than 8 mm in 3-, 4-, 5- and 6-strand HT graft configurations respectively. For the tibial end, 27%, 10%, 83%, and 92% of the patients achieved graft diameters of equal to or greater than 8 mm in 3-, 4-, 5-, and 6-strand HT graft configurations respectively. The largest increases in HT graft diameters were noted between the femoral end of 6- vs. 3-strand grafts (mean difference 1.7 ± 0.5 mm; p < 0.001) and between the tibial end of 6- vs. 4-strand grafts (mean difference 2.0 ± 0.5 mm; p < 0.001). Height and leg length were moderately positively correlated with ST tendon length (r = 0.54-0.51) and gracilis tendon length (r = 0.52-0.45), and thigh and shank lengths were moderately positively correlated with ST tendon length (r = 0.43 and 0.40, respectively).

CONCLUSION

Traditional 4-strand HT ACL autografts in male patients undergoing ACLR in the United Arab Emirates result in graft diameters less than 8 mm in the majority of patients.

LEVEL OF EVIDENCE

III.

The 50 Most Cited Articles in the Indications, Risk Factors, Techniques, and Outcomes of ACL Revision Surgery

The rate of anterior cruciate ligament (ACL) retear remains high and revision ACL reconstruction has worse outcomes compared with primaries. To make advances in this area, a strong understanding of influential research is necessary. One method for systematically evaluating the literature is by citation analysis. This article aims to establish and evaluate "classic" articles. With consideration of these articles, this article also aims to evaluate gaps in the field and determine where future research should be directed. The general approach for data collection and analysis consisted of planning objectives, employing a defined strategy, reviewing search results using a multistep and multiauthor approach with specific screening criteria, and analyzing data. The collective number of citations for all publications within the list was 5,203 with an average of 104 citations per publication. "Biomechanical Measures during Landing and Postural Stability Predict Second Anterior Cruciate Ligament Injury after Anterior Cruciate Ligament Reconstruction and Return to Sport" by Paterno et al contained both the highest number of total citations and the highest number of citations per year, with 403 total citations and 43.9 citations per year. The most recurring level of evidence were level II (n = 18) and level III (n = 17). "Clinical Outcomes" was the most common article type (n = 20) followed by "Risk Factors" (n = 10). The American Journal of Sports Medicine had the highest recorded Cite Factor with over 50% of the articles (n = 27) published. The most productive authors included R.W. Wright (n = 6), S.D. Barber-Westin (n = 5), F.R. Noyes (n = 5), and K.P. Spindler (n = 5). Historically, influential studies have been published in the realms of clinical outcome and risk factor identification. It has been established that revision ACL reconstruction has worse outcomes and more high-level studies are needed. Additionally, prospective studies that apply the knowledge for current known risk factor mitigation are needed to determine if graft tear rates can be lowered.

Radiographic Cam Morphology of the Hip May Be Associated with ACL Injury of the Knee: A Case-Control Study

Purpose

To evaluate femoral and acetabular morphology in patients who underwent anterior cruciate ligament reconstruction (ACLR).

Methods

A retrospective review of a prospectively collected ACL registry was performed to identify patients with pelvis radiographs before undergoing either primary or revision ACLR between January 2010 and August 2020. Alpha angle (AA), head-neck offset ratio (HNOR), lateral center edge angle (LCEA), and crossover sign (COS) were measured on the operative side. Values were compared to a negative control group that did not significantly differ in age, sex, or body mass index. Univariate analysis and Pearson’s correlation coefficient were used to compare groups with significance defined as P < .05.

Results

In total, 114 patients were included (ACL, n = 38; control, n = 76). Eleven primary and 27 revision ACL reconstructions were identified. The mean AA in patients undergoing primary ACL reconstruction was higher than control (67.45° ± 11.30° vs 51.5° ± 10.8°, P < .001). A significantly elevated AA was also found in those undergoing revision ACL surgery (61.8° ± 7.51° vs 51.5° ± 10.8°, P < .001). In addition, the HNOR was significantly lower in the ACL group (0.12 ± 0.03 vs 0.14 ± 0.04, P = .0304). Acetabular morphology was similar between groups (LCEA, ACL 31.97° ± 5.04° vs control 30.01° ± 5.17°, P = .0549; COS, ACL 9 of 38 (23.7%) vs control 18 of 76 (23.7%), P = 1.00).

Conclusion

An association exists between radiographic cam morphology of the hip and patients who previously underwent ACLR.

Level of Evidence

III, retrospective comparison study.

Augmentation of Primary ACL Reconstruction With a Modified Ellison Lateral Extra-articular Tenodesis in High-Risk Patients: A Pilot Study

BACKGROUND

Lateral extra-articular tenodesis (LET) has been used to augment primary anterior cruciate ligament (ACL) reconstruction to reduce the risk of reinjury. Most LET procedures result in a construct that is fixed to both the femur and the tibia. In a modified Ellison procedure, the construct is only fixed distally, reducing the risk of inadvertently overconstraining the lateral compartment.

PURPOSE

To evaluate the use of the modified Ellison procedure in a cohort of patients deemed to be at a high risk of further ACL injury after primary ACL reconstruction.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Included were 25 consecutive patients with at least 2 of the following risk factors: age <20 years at the time of surgery, previous contralateral ACL reconstruction, positive family history of ACL rupture (parent or sibling), generalized ligamentous laxity (Beighton ≥4), grade 3 pivot shift in the consulting room, a desire to return to a pivoting sport, and an elite or professional status. All patients underwent primary ACL reconstruction with an additional modified Ellison procedure. Postoperatively, patients completed the IKDC subjective knee evaluation form (International Knee Documentation Committee), KOOS Quality of Life subscale (Knee injury and Osteoarthritis Outcome Score), ACL-Return to Sport After Injury Scale, Marx Activity Rating Scale, and SANE score (Single Assessment Numeric Evaluation).

RESULTS

At 12-month follow-up, the mean outcome scores were as follows: SANE, 94/100; IKDC, 92/100; Marx, 13/16; ACL-Return to Sport, 85/100; and KOOS, 77/100. At 24 months, return-to-sport data were available for 23 of 25 patients; 17 (74%) were playing at the same level or higher than preinjury and 2 at a lower level. One patient (4%) sustained a contact mechanism graft rupture at 12 months. There were 2 (9%) contralateral ACL injuries, including 1 ACL graft rupture, at 11 and 22 months postoperatively. There was a further contralateral ACL graft rupture at 26 months.

CONCLUSION

The use of the modified Ellison procedure as a LET augmentation of a primary ACL reconstruction to produce a low graft rupture rate appeared to be safe in a cohort considered to be at a high risk of reinjury. The procedure showed promise in terms of reducing further graft injuries.

Can a Knee Brace Prevent ACL Reinjury: A Systematic Review

This systematic review aimed to investigate whether the use of a knee brace when returning to sport (RTS) could prevent a second injury after anterior cruciate ligament reconstruction (ACLR). This study was registered with the PROSPERO database and followed PRISMA guidelines. A systematic search of PubMed, Ovid Medline, Ovid All EBM Reviews, Ovid Embase, EBSCO Sportdiscus and ISI Web of Science databases for meta-analysis, randomized controlled trials and prospective cohort studies published before July 2020 was undertaken. The inclusion criteria were: (1) Comparing with and without a brace at RTS, (2) follow up of at least 18 months after ACLR, (3) reinjury rates included in the outcomes. Two reviewers independently extracted the data. Quality appraisal analyses were performed for each study using the Cochrane Collaboration tools for randomized and nonrandomized trials. A total of 1196 patients in three studies were included. One study showed a lower rate of reinjury when wearing a knee brace at RTS. One study found the knee brace to have a significant protective effect for younger patients (≤17 years). The effectiveness of knee bracing when RTS remains ambiguous. Current data cannot support that using a knee brace when RTS will decrease the rate of reinjury after ACL reconstruction.

Risk Factors for Septic Arthritis After Anterior Cruciate Ligament Reconstruction: A Nationwide Analysis of 26,014 ACL Reconstructions

BACKGROUND

Septic arthritis (SA) after anterior cruciate ligament reconstruction (ACLR) is a rare yet severe complication. The samples in previous studies have been small and without nationwide coverage, making analysis uncertain with a risk of bias. Conclusions to recommend preventive measures are therefore difficult to draw, and it has not been possible to perform a comprehensive risk factor analysis.

PURPOSE

To study the incidence of SA after ACLR in a large, nationwide population and to study the risk factors for SA after ACLR.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

All ACLRs, primary and revision, in the Swedish Knee Ligament Registry between 2006 and 2013 were linked with data from the Swedish National Board of Health and Welfare. The incidence of SA events was determined using entries from the day of surgery until 90 days postoperatively based on diagnosis codes and the prescription of antibiotics. All events of SA were verified via a review of medical records. Risk factors were analyzed based on data from the registries. Descriptive statistics were used to describe the findings, while logistic regression analysis was used for the risk analysis.

RESULTS

The cohort consisted of 26,014 primary and revision ACLRs. During the study period, 298 events of SA (1.1%) were identified. The high-volume units (≥500 ACLRs during the study period) had a distribution of SA between 2 and 47 (0.2%-2.9%). Independent risk factors of SA were male sex (OR, 1.65; 95% CI, 1.28-2.13), operating time ≥70 minutes (OR, 1.83; 95% CI, 1.42-2.36), hamstring tendon autograft (OR, 2.23; 95% CI, 1.21-4.08), and clindamycin as perioperative antibiotic prophylaxis (OR, 1.94; 95% CI, 1.10-3.41).

CONCLUSION

The incidence of SA after ACLR in this nationwide cohort was 1.1%. Male sex, hamstring tendon autografts, and a longer operating time were all independent risk factors for SA. The use of clindamycin as perioperative antibiotic prophylaxis was a risk factor compared with the use of cloxacillin. Some high-volume units had a very low infection rate (0.2%).

Low surgical routine increases revision rates after quadriceps tendon autograft for anterior cruciate ligament reconstruction: results from the Danish Knee Ligament Reconstruction Registry

PURPOSE

Recent registry data have demonstrated a higher revision rate of quadriceps tendon (QT) graft compared with hamstring tendon (HT) and patellar tendon (PT) grafts. Clinic routines could be an important factor for revision outcomes. The purpose of this study is to use the Danish Knee Ligament Reconstruction Registry (DKRR) to compare revision rates in patients who have undergone ACLR with QT, HT and PT grafts related to individual clinic surgical routine.

METHODS

Data on primary ACLRs entered in the DKRR from 2012 through 2019 were analysed since QT graft usage started in 2012. Revision rates for QT, HT and PT grafts were compared according to clinic activity (0-100 and > 100 procedures). Revision rates for the three autograft cohorts are presented, as well as adjusted revision hazard rates. Instrumented knee stability and pivot-shift tests were performed at a one-year follow-up.

RESULT

QT revision rate (6.4%) for low-activity clinics was higher than for high-activity clinics (2.9%) (p = 0.003). The adjusted revision hazard ratio for low-activity clinics was 2.3 (p = 0.01). QT autograft was associated with statistically significant, increased side-to-side laxity at follow-up (1.4 mm) compared with HT and PT autografts (1.0 mm) (p < 0.01), as well as an increased positive pivot-shift rate.

CONCLUSION

QT autografts for ACLR were associated with higher revision rates in clinics with lower than 100 procedures performed from 2012 to 2019. QT graft usage is not associated with a high revision rate when routinely performed. Learning curve is an important factor when introducing QT ACLR.

LEVEL OF EVIDENCE

Level III.