Earlier anterior cruciate ligament reconstruction is associated with a decreased risk of medial meniscal and articular cartilage damage in children and adolescents: a systematic review and meta-analysis

Management of Anterior Cruciate Ligament Tears in Skeletally Immature Patients

PURPOSE OF REVIEW

Anterior cruciate ligament (ALC) tears are increasingly common in skeletally immature patients, as more children and adolescents participate in intensive sports training and specialization at increasingly younger ages. These injuries were historically treated nonoperatively, given concerns for physeal damage and subsequent growth disturbances after traditional ACL reconstruction techniques. However, there is now sufficient data to suggest superior outcomes with operative treatment, specifically with physeal-sparing and physeal-respecting techniques. This article reviews considerations of skeletal maturity in patients with ACL tears, then discusses surgical techniques, with a focus on their unique indications and outcomes. Additional surgical adjuncts and components of postoperative rehabilitation, which may reduce retear rates, are also considered.

RECENT FINDINGS

Current research shows favorable patient-reported outcomes and high return-to-sport rates after ACL reconstruction in skeletally immature patients. Graft rupture (ACL retear) rates are low, but notably higher than in most adult populations. Historically, there has been insufficient research to comprehensively compare reconstruction techniques used in this patient population. However, thoughtful systematic reviews and multicenter prospective studies are emerging to address this deficit. Also, more recent data suggests the addition of lateral extra-articular procedures and stringent return-to-sports testing may lower retear rates. Physeal-sparing and physeal-respecting ACL reconstructions result in stabilization of the knee, while respecting the growth remaining in children or skeletally immature adolescents. Future research will be essential to compare these techniques, given that more than one may be appropriate for patients of a specific age and skeletal maturity.

Effect of Age and Body Mass Index on Time to Advanced Imaging and Surgery in Young Athletes With Anterior Cruciate Ligament Injury

Background

In young athletes with anterior cruciate ligament (ACL) injury, increased times from injury to magnetic resonance imaging (MRI) and injury to surgery can lead to the accrual of new injuries over time.

Purpose

To determine the patient characteristics associated with differences in timing between injury, MRI, and surgery in young athletes with ACL tears.

Study Design

Case-control study; Level of evidence, 3.

Methods

We reviewed the electronic medical records of patients aged 13 to 25 years who underwent isolated primary ACL reconstruction between January 2017 and June 2020 at a single orthopaedic surgery department. The times from injury to MRI, MRI to surgery, and injury to surgery were documented. Patient demographic data (age, sex, body mass index [BMI], race and ethnicity, and insurance type) were recorded. Multivariable analysis was used to determine if any patient characteristic had a significant association with increased time to MRI or surgery.

Results

A total of 369 patients (mean age, 18.0 years; 56% female) were included. Both age and BMI were found to be significantly associated with timing of care while holding all other predictors constant. For every 1-year increase in patient age, time from injury to MRI increased by 9.6 days (95% CI, 1.8-17.4 days; P = .02), time from MRI to surgery increased by 7.4 days (95% CI, 4.4-10.5 days; P < .001), and time from injury to surgery increased by 17.0 days (95% CI, 8.4-25.6 days; P < .001). Compared with patients with normal BMI, overweight patients (BMI range, 25-29.9 kg/m2) had an MRI-to-surgery time that was on average 37.2 days (95% CI, 11.7-62.7 days; P < .004) longer and an injury to surgery time that was on average 71.8 days (95% CI, 0.5-143.0 days; P = .048) longer. Obese patients (BMI ≥30 kg/m2) did not demonstrate a significant relationship with the studied time intervals.

Conclusion

Increasing age and elevated BMI were found to be associated with increased time to MRI and surgical care in young athletes with ACL injuries.

IL-6 induces periostin production in human ACL remnants: a possible mechanism causing post-traumatic osteoarthritis

OBJECTIVE

Perostin (POSTN) and IL-6 consistently elevated after ACL injury, and ACL has been proposed as the major source of POSTN. However, there is a lack of evidence whether IL-6 induces ACL remnants to produce POSTN. This study aimed to investigate the effect of IL-6 on POSTN production in ACL fibroblasts, which may help us understand more about the mechanism of PTOA after ACL injury and ACL reconstruction.

METHODS

ACL remnants were harvested from 27 patients undergoing ACL reconstruction. Quantitative real-time polymerase chain reaction (PCR) was performed to examine the POSTN gene expression of ACL fibroblasts after treatment of different concentrations of IL-6. The POSTN protein production of ACL fibroblasts was determined using western blot analysis. The blockers of possible signaling pathways, including PI3K/Akt, Ras/MAPK, and JAK/STAT pathways, were added to test whether the effect of IL-6 on ACL fibroblast could be attenuated. ACL fibroblast and chondrocyte co-culture was carried out to determine the influence of ACL and IL-6 on chondrocytes.

RESULTS

Quantitative real-time PCR showed that IL-6 time-dependently and dose-dependently increased POSTN gene expression of ACL fibroblast. Western blot analysis also revealed that IL-6 dose-dependently induced POSTN protein production. Regarding the chronicity of ACL injury, the POSTN protein production was comparable between ACL remnants which were derived within 3 months of injury and at least 6 months after injury. PI3K/Akt blockers could attenuate the effect of IL-6 on ACL remnants, whereas Ras/MAPK and JAK/STAT did not decrease POSTN production. The coexistence of ACL and IL-6 induced more MMP-13 and ADAMTS-4 by chondrocytes.

CONCLUSIONS

IL-6 induced ACL remnants to produce POSTN. This effect could be attenuated by the PI3K/Akt blocker. Coexistence of IL-6 and ACL remnants may accelerate post-traumatic arthritis.

Risk Factors of Loss of Knee Range of Motion after Primary Anterior Cruciate Ligament Reconstruction following Preoperative Recovery of Knee Range of Motion

The loss of knee range of motion (ROM) is not an uncommon complication after anterior cruciate ligament reconstruction (ACLR). However, the risk factors of loss of knee ROM remain debatable. The purpose of this study was to evaluate the incidence and risk factors of loss of knee ROM at 12 months after primary ACLR performed after regaining full knee ROM preoperatively. Consecutive patients who underwent primary ACLR after regaining full ROM between January 2014 and January 2020 were retrospectively reviewed. Patients who received a surgical arthrolysis within 12 months after ACLR or those who had a loss of knee ROM at 12 months postoperatively were defined as the loss of ROM group. Possible risk factors of loss of knee ROM, including patient demographic, preoperative, surgical, and postoperative factors, were assessed. The notch wide index and radiographic parameters of the tibial spines; medial tibial spine height/tibial length (TL), lateral tibial spine height (LTSH)/TL, and tibial spine width (TSW)/TL, were also assessed. A total of 141 patients (141 knees) were included (mean age, 25.8 ± 11.4 years; male/female, 56/85). Of the 141 patients, three received surgical arthrolysis within 12 months, and 23 had a loss of knee ROM at 12 months after ACLR. On comparing patients with and without loss of knee ROM, significant differences were found in the age (p = 0.04), LTSH/TL (p = 0.02), and TSW/TL (p = 0.02). A multivariate regression analysis showed that the age (odds ratio [OR]; 1.05, 95% confidence interval [CI]: 1.01-1.09, p = 0.02), LTSH/TL (OR: 1.44, 95% CI: 1.01-2.1, p = 0.04), and TSW/TL (OR: 0.79, 95% CI: 0.65-0.97, p = 0.02) were identified as significant independent risk predictors of loss of knee ROM. This study showed that the incidence of loss of knee ROM at 12 months after primary ACLR was 18.4% (26/141). An older age, a higher LTSH/TL, and a smaller TSW/TL may be associated with loss of knee ROM at 12 months after ACLR.

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

Background

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

Purpose/Hypothesis

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

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

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

Results

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

Conclusion

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

Is Delayed Anterior Cruciate Ligament Reconstruction Associated With a Risk of New Meniscal Tears? Reevaluating a Longstanding Paradigm

Background

Delayed anterior cruciate ligament (ACL) reconstruction has been associated with an increased risk of meniscal tears. However, studies comparing early versus delayed ACL reconstruction have not clearly demonstrated that meniscal tears diagnosed arthroscopically are new injuries as opposed to concomitant injuries sustained during ACL rupture.

Purpose

To determine whether and how delay of ACL reconstruction is associated with risk of "new" meniscal tears (defined as those visualized arthroscopically that had not been detected on magnetic resonance imaging [MRI]) in adult and pediatric patients.

Study Design

Cohort study; Level of evidence, 3.

Methods

We retrospectively identified patients who underwent primary ACL reconstruction between 2013 and 2022 at our institution. To ensure that MRI reflected initial intra-articular pathology, we included only patients who had an MRI scan within 3 weeks after injury (173 pediatric and 369 adult patients). Multivariate Poisson regression was performed to calculate the adjusted relative risk (ARR) of new meniscal tears after delayed (≥8 weeks from injury) operative treatment.

Results

The mean (± SD) time from injury to MRI was 1.0 ± 0.8 weeks for pediatric patients and 1.1 ± 0.7 weeks for adults. Less than half of the meniscal tears observed arthroscopically had been absent on initial MRI. New medial meniscal tears occurred in 15% of pediatric patients and 16% of adults. New lateral meniscal tears occurred in 48% of pediatric patients and 34% of adults. Among pediatric patients, delayed ACL reconstruction was associated with higher risk of new medial tears (ARR, 3.9; 95% CI, 1.5-10) but not lateral tears (ARR, 0.8; 95% CI, 0.4-1.5). In contrast, adults had no significant increase in risk of meniscal tears associated with operative delay.

Conclusion

Delayed ACL reconstruction may be acceptable in adults, who may be less active and less injury-prone than children and adolescents.

Management of Pediatric Anterior Cruciate Ligament Injuries: A Critical Analysis

» Overall evidence for the treatment of an anterior cruciate ligament (ACL) injury in a pediatric or skeletally immature patient remains lows.» An ACL reconstruction is recommended with concomitant repairable chondral and meniscus injury or with symptoms of persistent instability despite high-quality rehabilitation.» Treatment decision for pediatric ACL reconstruction should use a shared decision-making model weighing the risks and benefits of both a nonoperative vs. surgical treatment.

Graft choices for paediatric anterior cruciate ligament reconstruction: State of the art

The paediatric population is at particularly high risk for anterior cruciate ligament (ACL) injuries due to high rates of sports participation. Other risk factors for ACL injuries in children include but are not limited to being female, generalised ligamentous laxity, a high body mass index (BMI), and poor neuromuscular control. ACL reconstruction (ACLR) is commonly done to treat ACL injuries and allow for return to sports and daily activities. ACL repair is another option with ongoing techniques being developed. The high rates of graft failure in children reported in recent publications on ACL repair are very concerning. Special consideration must be taken in ACLR in the skeletally immature patient due to the risk of growth-related complications, such as limb deformity or growth arrest, that can arise from drilling across or disrupting the physis. Graft choices for paediatric ACLR include iliotibial band (ITB) over the top and over the front, hamstring autograft, bone patellar tendon bone (BTB) autograft, quadriceps tendon autograft, and allograft. Factors for each graft choice to consider include graft size, graft failure rates, donor site morbidity, requirement for bony tunnels, the post-op rehabilitation process, and return to sport outcomes. Each graft has its benefits and disadvantages for the individual patient, depending on age, skeletal maturity, and goals for recovery. Lateral extra-articular tenodesis (LET) is another option to consider with paediatric ACLR because LET has been shown to decrease the re-rupture rate in adult ACLR. After surgery, patient follow-up until at least the growth plates are closed is important. This article aims to provide an overview and comparison of the various graft types to aid in the graft choice decision making process for paediatric ACLR.

Treating Combined Anterior Cruciate Ligament and Medial Collateral Ligament Injuries Operatively in the Acute Setting Is Potentially Advantageous

Combined injury of the anterior cruciate ligament (ACL) and medial collateral ligament (MCL) remains among the most common knee injury patterns in orthopaedics. Optimal treatment of grade III MCL injuries is still debated, especially when combined with ACL injury. Most patients with these severe injuries are treated conservatively for at least 6 weeks to allow for MCL healing, followed by delayed ACL reconstruction. Although acute treatment of the MCL was common in the 1970s, postoperative stiffness was frequently reported. Moreover, studies of such treatment failed to show clinical benefits of surgical over conservative treatment, and the MCL exhibited intrinsic healing capacity, leading to the consensus that all MCL injuries are treated conservatively. The current delayed treatment algorithm for ACL-MCL injuries has several disadvantages. First, MCL healing may be incomplete, resulting in residual valgus laxity that places the ACL graft at greater risk of failure. Second, delayed treatment lengthens the overall rehabilitation period, thereby prolonging the presence of atrophy and delaying return to preinjury activity levels. Third, the initial healing period leaves the knee unstable for longer and risks further intra-articular damage. Acute simultaneous surgical treatment of both ligaments has the potential to avoid these shortcomings. This article will review the evolution of treatment of ACL-MCL injuries and explain how it shifted toward the current treatment algorithm. We will (1) discuss why the consensus shifted, (2) discuss the shortcomings of the current treatment plan, (3) discuss the potential advantages of acute simultaneous treatment, and (4) present an overview of the available literature.

Effect of Delayed Anterior Cruciate Ligament Reconstruction on Repair of Concomitant Medial Meniscus Tears in Young Athletes

BACKGROUND

Delayed anterior cruciate ligament (ACL) reconstruction (ACLR) is associated with an increased risk of meniscal injury. Limited data are available regarding the relationship between surgical delay and meniscal repairability in the setting of ACLR in young patients.

PURPOSE

To determine whether time from ACL injury to primary ACLR was associated with the incidence of medial and/or lateral meniscal repair in young athletes who underwent meniscal treatment at the time of ACLR.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Records were retrospectively reviewed for patients aged 13 to 25 years who underwent primary ACLR between January 2017 and June 2020 by surgeons from a single academic orthopaedic surgery department. Demographic data were collected, and operative reports were reviewed to document all concomitant pathologies and procedures. Univariable and multivariable logistic regression analyses were used to determine factors associated with meniscal repair, including time elapsed from ACL injury to surgery.

RESULTS

Concomitant meniscal tears were identified and treated in 243 of 427 patients; their mean age was 17.9 ± 3.3 years, and approximately half (47.7%) of patients were female. There were 144 (59.3%) medial tears treated and 164 (67.5%) lateral tears treated; 65 (26.7%) patients had both medial and lateral tears treated. Median time from ACL injury to ACLR was 2.4 months (interquartile range, 1.4-4.7 months). Adjusted univariate analysis showed a statistically significant correlation between medial meniscal repair and time to surgery, with a 7% decreased incidence of medial meniscal repair per month elapsed between injury and surgery (odds ratio, 0.93 per month; 95% CI, 0.89-0.98; P = .006). No similar relationship was found between lateral meniscal repair and time to surgery (odds ratio, 1.02; 95% CI, 0.99-1.06; P = .24).

CONCLUSION

In the setting of concomitant ACL and meniscal injuries, surgical delay decreased the incidence of medial meniscal repair in young athletes by 7% per month from time of injury.

Rare Fracture Knee Dislocation Treated with Ligament Repair and Novel Arcuate Fracture Repair Technique: A Case Report

CASE

A 57-year-old man presented with a left knee dislocation after a motor vehicle collision. Clinical and imaging evaluation demonstrated disruption of the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), anterolateral ligament (ALL), and posterolateral corner (PLC). The patient underwent acute, single-stage arthroscopic primary ACL and PCL repair, with arcuate fracture fixation using a novel technique. At 4 years postoperatively, he continues to do well subjectively with minimal clinical laxity.

CONCLUSION

Acute, single-stage arthroscopic primary ligamentous repair is a viable option for high-grade multiligamentous knee dislocations and may be combined with our novel technique for arcuate fracture fixation.

LEVEL OF EVIDENCE

Level IV, Case Report.

Acute and subacute anterior cruciate ligament reconstructions are associated with a higher risk of revision and reoperation

PURPOSE

(1) Report concomitant cartilage and meniscal injury at the time of anterior cruciate ligament reconstruction (ACLR), (2) evaluate the risk of aseptic revision ACLR during follow-up, and (3) evaluate the risk of aseptic ipsilateral reoperation during follow-up.

METHODS

Using a United States integrated healthcare system's ACLR registry, patients who underwent primary isolated ACLR were identified (2010-2018). Multivariable Cox proportional-hazards regression was used to evaluate the risk of aseptic revision, with a secondary outcome evaluating ipsilateral aseptic reoperation. Outcomes were evaluated by time from injury to ACLR: acute (< 3 weeks), subacute (3 weeks-3 months), delayed (3-9 months), and chronic (≥ 9 months).

RESULTS

The final sample included 270 acute (< 3 weeks), 5971 subacute (3 weeks-3 months), 5959 delayed (3-9 months), and 3595 chronic (≥ 9 months) ACLR. Medial meniscus [55.4% (1990/3595 chronic) vs 38.9% (105/270 acute)] and chondral injuries [40.0% (1437/3595 chronic) vs 24.8% (67/270 acute)] at the time of ACLR were more common in the chronic versus acute groups. The crude 6-year revision rate was 12.9% for acute ACLR, 7.0% for subacute, 5.1% for delayed, and 4.4% for chronic ACLR; reoperation rates a 6-year follow-up was 15.0% for acute ACLR, 9.6% for subacute, 6.4% for delayed, and 8.1% for chronic ACLR. After adjustment for covariates, acute and subacute ACLR had higher risks for aseptic revision (acute HR 1.70, 95% CI 1.07-2.72, p = 0.026; subacute HR 1.25, 95% CI 1.01-1.55, p = 0.040) and aseptic reoperation (acute HR 2.04, 95% CI 1.43-2.91, p < 0.001; subacute HR 1.31, 95% CI 1.11-1.54, p = 0.002) when compared to chronic ACLR.

CONCLUSIONS

In this cohort study, while more meniscal and chondral injuries were reported for ACLR performed ≥ 9 months after the date of injury, a lower risk of revision and reoperation was observed following chronic ACLR relative to patients undergoing surgery in acute or subacute fashions.

Risk of reoperation after primary anterior cruciate ligament reconstruction in children and adolescents

OBJECTIVE

To examine the incidence and risk factors of any-cause reoperation after primary ACLR in children and adolescents.

DESIGN

Retrospective Cohort.

SETTING

Electronic medical records from a large tertiary care, single institution integrated healthcare delivery system.

PATIENTS

Patients were under the age of 18 years and had anterior cruciate ligament reconstruction. They were excluded if they had a multi-ligamentous knee injury or <1 year follow-up.

INTERVENTIONS

Patients were further identified to have undergone a subsequent knee operation ipsilaterally or contralateral ACLR.

MAIN OUTCOME MEASURES

The rate of any-cause reoperation was our primary outcome measure.

RESULTS

The median age was 16. There were 208 females (53.9%) and 178 males (46.1%) included. The median follow-up was 25 months with a minimum of 12 months (interquartile range: 16.0, 46.0). The rate of any-cause reoperation was 34.7%. There was no statistically significant difference between those who underwent reoperation versus those who did not undergo reoperation relative to age, sex, BMI, graft type, or the presence of concomitant meniscal injury. The rates of ipsilateral ACLR and contralateral ACLR at any time during the study period was 8.0% and 10.9% respectively. There was no statistically significant difference for rate of reoperation between graft types, between various concomitant injuries, between those who underwent meniscus repair or no repair.

CONCLUSIONS

This study reflects a 34.7% rate of a subsequent knee operation after ACLR in patients younger than 18 years. These findings can be used to inform pediatric patients undergoing primary ACLR on their risk of returning to the operating room.

Does Surgery for Concomitant Cruciate and Meniscus Injuries Increase or Decrease Subsequent Comorbidities at 2 Years?

Concomitant cruciate and meniscus injuries of the knee are generally associated with acute trauma and commonly treated with surgical intervention. Comorbidities (simultaneous presence of two or more medical conditions) may be acquired from changes in activity levels and lifestyle after an injury and/or treatment. This study aimed to compare differences in comorbidity proportions between surgical and nonsurgical approaches in Military Health System beneficiaries who had concurrent cruciate and meniscus injuries. The retrospective case control design included 36-month data that were analyzed to reflect 12 months prior to injury/surgery and 24 months after injury/surgery. A comparison of differences within and between groups in surgical and nonsurgical approaches was calculated and logistic regression was used to determine if surgery increased or decreased the odds of comorbidities at 24 months. In our sample of 2,438 individuals with concurrent meniscus and cruciate injury, 79.1% (n = 1,927) received surgical intervention and 20.9% (n = 511) elected for nonoperative management. All comorbidities demonstrated significant within-group differences from pre- to postsurgery for those with a surgical intervention; approximately, half the comorbidities increased (i.e., concussion or traumatic brain injury, insomnia, other sleep disorders, anxiety, posttraumatic stress disorder, and tobacco abuse disorder), whereas the other half decreased (i.e., chronic pain, apnea, cardiovascular disease, metabolic syndrome, mental health other, depression, and substance abuse disorders). The odds of acquiring a comorbid diagnosis after surgery reflected the bivariate comparisons with half increasing and half decreasing in odds. To our knowledge, this is the first study to explore comorbidity changes with a control group for individuals with concurrent meniscus and cruciate injuries.

17-Year Results following Transepiphyseal Anterior Cruciate Ligament Reconstruction in Children and Adolescents

OBJECTIVE

Rupture of the anterior cruciate ligament (ACL) in childhood and adolescence is a serious injury. It is now known that conservative therapy of an unstable knee joint in childhood or adolescence under can lead to poor subjective and objective results. The aim of this study is to record long-term results after transepiphyseal ACL reconstruction using autologous hamstring tendons and extracortical fixation in childhood and adolescence with open physes - at least 15 years after surgery.

METHODS

Our internal registry was used to identify all patients who received surgical treatment of an acl tear during childhood and adolescence by transepiphyseal acl reconstruction more than 15 years previously. In these patients, the International Knee Documentation Committee for Subjective Knee Form (IKDCsubj.), Knee Injury and Osteoarthritis Outcome Score (KOOS), Tegner Activity Score (TAS) and Lysholm Score were collected, and clinical and magnetic resonance imaging (MRI) examinations were performed.

RESULTS

A total of 22 patients were identified, 5 of whom could not be contacted. The mean age at the time of surgery was 13.1 years, and the mean follow-up time was 17.4 years. In 3 patients, a traumatic tear was observed with subsequent reconstruction of the ACL. None of the included patients showed a growth disorder during the course of the study. The IKDC_subj. was 92.4 ± 14.7 (48 - 100), the Lysholm score was 87.9 ± 16.9 (34 - 100), the TAS was 5.7 ± 2.3 (3 - 9) and the pain level based on VAS was 3.5 ± 2.6 (1 - 8) points. The values showed subjective and objective deterioration compared to the 10-year results, with no statistical significance. The following subscores were reported for the KOOS: KOOS_pain 90.9 ± 17.6 (28 - 100); KOOS_symptom 82.9 ± 22.6 (11 - 100); KOOOS_ADL 94.3 ± 13.7 (44 - 100); KOOS_Sport 80.3 ± 26.4 (15 - 100); KOOS_QOL 80.9 ± 25.8 (0 - 100). 13 of the 17 patients could also be clinically and radiologically examined. In 92% of patients, an intact acl reconstruction was found without evidence of cartilage or meniscus damage. The mean lateral difference in the KT-1000 measurement was 1.5 mm.

CONCLUSION

ACL reconstruction in childhood and adolescence provides good functionality and stability of the knee joint over the long term. Secondary signs of osteoarthritis can only be detected in isolated cases by MRI. ACL reconstruction using the transepiphyseal technique can be considered the method of choice for open growth plate knee joints.

Assessment of Skeletal Maturity and Postoperative Growth Disturbance After Anterior Cruciate Ligament Reconstruction in Skeletally Immature Patients: A Systematic Review

BACKGROUND

Growth disturbance is an uncommon but potentially serious complication after anterior cruciate ligament (ACL) reconstruction in skeletally immature patients.

PURPOSE

To describe how the pediatric ACL literature has assessed preoperative skeletal maturity and the amount of growth remaining and to comprehensively review the incidence, reporting, and monitoring of postoperative growth disturbance.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

This review included studies reporting original research of clinical outcomes of skeletally immature patients after ACL reconstruction. Patient characteristics, surgical techniques, preoperative assessments of skeletal maturity or growth remaining, and postoperative assessments of growth disturbances were extracted.

RESULTS

A total of 100 studies met inclusion criteria. All studies reported chronological age, and 28 studies (28%) assessed skeletal age. A total of 44 studies (44%) used Tanner staging, and 12 studies (12%) obtained standing hip-to-ankle radiographs preoperatively. In total, 42 patients (2.1%) demonstrated a leg length discrepancy (LLD) >10 mm postoperatively, including 9 patients (0.5%) with LLD >20 mm; furthermore, 11 patients (0.6%) with LLD underwent growth modulation. Shortening was the most common deformity overall, but overgrowth was reported more frequently in patients who had undergone all-epiphyseal techniques. Most LLDs involved the femur (83%). A total of 26 patients (1.3%) demonstrated a postoperative angular deformity ≥5°, and 9 of these patients underwent growth modulation. The most common deformities were femoral valgus (41%), tibial recurvatum (33%), and tibial varus (22%). Although standing hip-to-ankle radiographs were the most common radiographic assessment of growth disturbance, most studies inadequately reported the clinical and radiographic methods of assessment for growth disturbance. Additionally, only 35% of studies explicitly followed patients to skeletal maturity.

CONCLUSION

This systematic review described significant variability in the reporting and monitoring of growth-related complications after ACL reconstruction in skeletally immature patients. The incidence of LLD and angular deformity appeared to be low, but the quality of research was not comprehensive enough for accurate assessment.

REGISTRATION

CRD42019136059 (PROSPERO).

Graft Choice for Anterior Cruciate Ligament Reconstruction in Women Aged 25 Years and Younger: A Systematic Review

CONTEXT

Although anterior cruciate ligament (ACL) tears are relatively common in athletic populations, few studies have systematically reviewed graft choice in young women.

OBJECTIVE

To quantitatively and qualitatively examine reported outcomes for graft choice in women aged 25 years and younger undergoing primary ACL reconstruction.

DATA SOURCE

A systematic review was performed using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. An electronic search in the PubMed (includes MEDLINE) and EMBASE databases was completed using a combination of key terms.

STUDY SELECTION

Studies were included if they reported graft choice outcomes in women aged 25 years and younger.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

The following information was extracted: title, author, year of publication, number of female patients and age, graft type, follow-up, and patient-reported outcome measures. The following outcome scores were identified as being reported or not reported by each study: graft failure, contralateral ACL (CACL) rupture, IKDC (International Knee Documentation Committee), graft survival (Kaplan-Meier), Lysholm, Tegner, KT-1000, kneeling pain, return to sport, and Lachman.

RESULTS

Of 1170 identified articles, 16 met inclusion criteria, reporting on 1385 female patients aged 25 years and younger. Comparison of 655 bone-patellar tendon-bone (BPTB) versus 525 hamstring tendon (HT) autografts showed significant differences in mean failure rate between BPTB autografts (6.13% ± 2.58%) and HT autografts (17.35% ± 8.19%), P = 0.001. No statistically significant differences in CACL failure rates were found between BPTB autografts and HT autografts (P = 0.25). Pooled results for IKDC were possible in 3 of the HT autograft studies, showing a mean score of 88.31 (95% CI 83.53-93.08). Pooled Lysholm score results were possible in 2 of the HT autograft studies, showing a mean score of 93.46 (95% CI 91.90-95.01).

CONCLUSION

In female patients aged 25 years and younger, BPTB autografts showed significantly less graft failure compared with HT autografts. However, BPTB autografts had comparable patient-reported outcomes compared with HT autografts with the available data. The overall state of evidence for graft choice in female patients aged 25 years and younger is low. Future studies should report statistics by age and sex to allow for further analysis of graft choice for this specific population that is known to be more vulnerable to ACL injury.

Outcomes of pediatric anterior cruciate ligament reconstructions in patients with and without bucket handle meniscus repairs

The purpose of this study was to report the outcomes of concomitant bucket handle meniscal tear (BHMT) repair and anterior cruciate ligament (ACL) reconstruction and to compare the outcomes with those after isolated ACL reconstruction in patients aged ≤16 years. Patients in our database from 2013 to 2017 were retrospectively analyzed. Patients were assigned to one of two treatment groups based on the presence of BHMTs: no meniscal tear group (group A) and BHMT group (group B). All BHMTs were repaired using the combined inside-out with all-inside technique. This study included 64 knees divided into two groups: 47 knees in group A and 17 knees in group B. There was a significant difference in the interval between ACL injury and surgery between groups A and B (69 vs. 150 days, respectively; P < 0.001). Mean postoperative International Knee Documentation Committee and Lysholm scores in group A were slightly, although significantly, improved compared to those in group B (96.5 vs. 92.6, respectively; P < 0.05, and 98 vs. 95, respectively; P < 0.05). There were no significant differences in postoperative anteroposterior laxity and graft failure rate between the groups. In group B, four patients (23.5%) required surgery for incomplete meniscal healing. Postoperative International Knee Documentation Committee and Lysholm scores of patients with BHMTs were significantly lower than those of patients without any meniscal tear, although with significant improvement in the amount of instability. Level of evidence was Level III.

An older age, a longer duration between injury and surgery, and positive pivot shift test results increase the prevalence of articular cartilage injury during ACL reconstruction in all three compartments of the knee in patients with ACL injuries

PURPOSE

To investigate factors that influence the prevalence of articular cartilage injury in patients with anterior cruciate ligament (ACL) injury.

METHODS

This multicentre study included patients with ACL injury. Logistic regression analysis was conducted to identify factors that influence the prevalence of cartilage injury during ACL reconstruction.

RESULTS

A total of 811 patients were enrolled. The factors that significantly influenced the prevalence of cartilage injury were age (odds ratio [OR], 1.04; P = 0.000), a positive pivot shift test result (OR, 1.43; P = 0.021), medial meniscal injury (OR, 2.55; P = 0.000), and delayed surgery (≥ 12 months) (OR, 2.52; P = 0.028) in the medial compartment of the knee; age (OR, 1.05; P = 0.000), subjective grades of apprehension during the pivot shift test (OR, 1.46; P = 0.010), lateral meniscal injury (OR, 1.98; P = 0.003), femoro-tibial angle (FTA) (OR, 0.92; P = 0.006), and delayed surgery (≥ 12 months) (OR, 2.63; P = 0.001) in the lateral compartment; and age (OR, 1.06; P = 0.000), body mass index (OR, 1.07; P = 0.028), a positive pivot shift test result (OR, 1.60; P = 0.018), FTA (OR, 0.90; P = 0.006), and delayed surgery (≥ 12 months) (OR, 3.17; P = 0.008) in the patellofemoral compartment.

CONCLUSION

An older age, a longer duration between injury and surgery, and a positive pivot shift test result were positively associated with the prevalence of cartilage injury in three compartments in patients with ACL injuries. Early ACL reconstruction is recommended to prevent cartilage injury.

LEVEL OF EVIDENCE

Level III.

Delaying ACL reconstruction beyond 6 months from injury impacts likelihood for clinically significant outcome improvement

BACKGROUND

The effect of surgical latency on outcomes of anterior cruciate ligament reconstruction (ACLR) is a topic that is heavily debated. Some studies report increased benefit when time from injury to surgery is decreased while other studies report no benefit. The purpose of our analysis was to compare achievement of clinically significant outcomes (CSOs) in patients with greater than six months of time from injury to ACLR to those with less than or equal to six months of time to surgery.

METHODS

Patients undergoing primary ACLR between January 2017 and January 2018 with minimum one year follow-up were included. International Knee Documentation Committee (IKDC) score and Knee Injury and Osteoarthritis Outcomes Score (KOOS) were collected. Multivariate logistic regression was performed for outcome achievement and risk of revision ACLR and Weibull parametric survival analysis was performed for relative time to outcome achievement. The level of significance was set at α = 0.05.

RESULTS

379 patients were included of which, 140 patients sustained ACL injury greater than six months prior to surgery. This group of patients experienced reduced likelihood to achieve patient-acceptable symptomatic state (PASS) on the IKDC (p = 0.03), KOOS Pain (p = 0.01) and a greater likelihood to undergo revision ACLR (p = 0.001). There was no impact of surgical timing on minimal clinically important difference (MCID).

CONCLUSION

Patients with greater than 6 months from injury to ACLR reported reduced likelihood to achieve CSOs, delayed achievement of CSOs, and increased rates of revision surgery.

Elevated BMI increases concurrent pathology and operative time in adolescent ACL reconstruction

PURPOSE

The purpose of this study was to (1) report on the incidence of concurrent surgical pathology at the time of adolescent ACL reconstruction, (2) evaluate patient risk factors for concurrent pathology, and (3) measure the effect of BMI on operating room (OR) time.

METHODS

A retrospective analysis of the NSQIP database for the years 2005-2017 was conducted. Nine-hundred and seventeen patients 18 years of age and younger who underwent ACL reconstruction (ACLR) were identified using CPT code 29888 and patients undergoing surgery for multi-ligamentous knee injuries were excluded. The mean patient age was 17.6 years (range 14-18, standard deviation 0.52) and consisted of 546 males (59.5%) and 371 females (40.5%). Logistic regression was used to assess the relationship between BMI and additional CPT codes for internal derangement at the time of surgery. Internal derangement was defined as any procedure for the treatment of a meniscal tear, chondral lesion, or loose body removal. Linear regression analysis was then performed to evaluate the effect of BMI on operative time.

RESULTS

43.7% of patients undergoing ACLR required an associated procedure for internal derangement. Additionally, the risk of requiring additional procedures for internal derangement increased by 3.1% per BMI point. BMI was also predictive of operative time, independent of the number of additional procedures. Specifically, the operative time increased by nearly one minute for every point increase in BMI (58.0 s).

CONCLUSIONS

Adolescent patients with an elevated BMI were much more likely to require additional surgical procedures for internal derangement at the time of ACL reconstruction. Additionally, BMI was a significant predictor for longer operative times.

LEVEL OF EVIDENCE

Level III.

The influence of the steep medial posterior tibial slope on medial meniscus tears in adolescent patients: a retrospective case-control study

Background

Several studies have demonstrated a relationship between the posterior tibial slope (PTS) and meniscal tears in adults. However, little is known about the association between the PTS of the adolescents and medial meniscal tears (MMT). The purpose of this study was to evaluate the association between the PTS and MMT in adolescents, and to determine the optimal cut-off values of PTS for discriminating between the MMT and the control groups.

Methods

Between January 2018 and January 2020, a retrospective case-control study was performed. In this study, isolated MMT adolescent patients with no ligamentous injuries were matched by age and sex to a control group of radiologically normal images. The PTS was defined as the angle between the perpendicular line to proximal tibial cortex (PTC) and the tangent line along the tibial plateau. Then, both the medial posterior tibial slope (MPTS) and lateral posterior tibial slope (LPTS) were measured by plain radiographs on the lateral views. In addition, the optimal cut-off values of PTS were determined by the receiver operating characteristic (ROC) curve analysis.

Results

A total of seventy-two patients who met the inclusion criteria were enrolled in the final analysis (36 patients with isolated MMT, 36 controls). The MPTS was greater in the knees with isolated MMT (10.7° ± 2.1°) than that of the control group (8.8° ± 1.7°), showing significant difference (P<0.001). However, there was no significant difference regarding the LPTS between the isolated MMT and controls (11.5 ± 3.4 vs 10.9 ± 2.6, p>0.05). In the ROC curve analysis, the calculated cutoff value of the MPTS discriminating between the groups was 10.3°, with a sensitivity of 73.3% and specificity of 78.9%.

Conclusions

This study demonstrated that steep MPTS is associated with MMT, and MPTS≥10.3° was identified to be a risk factor for MMT in adolescents.

Association Between Knee Alignment and Meniscal Tear in Pediatric Patients with Anterior Cruciate Ligament Injury

BACKGROUND

The present study aimed to evaluate the association between elapsed time from anterior cruciate ligament (ACL) injury to surgical treatment and the incidence of meniscal tears in a cohort of patients ≤16 years old with varus-aligned and non-varus-aligned knees.

METHODS

The study cohort included 123 patients ≤16 years old who underwent primary ACL reconstruction between January 2016 and March 2020. Knee alignment was expressed as the hip-knee-ankle angle (HKAA), as measured preoperatively on an anteroposterior view of 3-dimensional computed tomography of the full length of the lower limb. Varus alignment was defined as an HKAA ≥181.0°, and non-varus alignment was defined as an HKAA <181.0°. Patients were divided into groups according to knee alignment and the elapsed time from injury to surgical treatment: early-treatment group (<60 days) and delayed-treatment group (≥60 days).

RESULTS

A total of 64 varus-aligned and 59 non-varus-aligned knees were identified. Among patients with varus-aligned knees, those in the delayed-treatment group showed a significantly lower rate of lateral meniscal tears (6 of 30, 20%) compared with those in the early-treatment group (17 of 34, 50%; p = 0.015). Among patients with non-varus-aligned knees, there was no significant difference in meniscal tears of any type between the early and delayed-treatment groups. Among patients without medial meniscal injury identified on initial magnetic resonance imaging, those with varus-aligned knees in the delayed-treatment group showed a significantly higher rate of medial meniscal tears at the time of the surgical procedure (8 of 20, 40%) compared with those with non-varus-aligned knees (1 of 18, 6%; p = 0.015).

CONCLUSIONS

Delayed ACL reconstruction in patients ≤16 years old with varus-aligned knees might be associated with an increased incidence of secondary medial meniscal tears. Accordingly, earlier ACL reconstruction in patients with varus-aligned knees should be considered.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Female gender and medial meniscal lesions are associated with increased pain and symptoms following anterior cruciate ligament reconstruction in patients aged over 50 years

PURPOSE

Several studies report satisfactory clinical outcomes following ACLR in older patients, but none evaluated the effects of meniscal and cartilage lesions. The aim was to evaluate the influence of meniscal and cartilage lesions on outcomes of ACLR in patients aged over 50 years.

METHODS

The authors prospectively collected records of 228 patients that underwent primary ACLR, including demographics, time from injury to surgery, whether injuries were work related, and sports level (competitive, recreational, or none). At a minimum follow-up of 6 months, knee injury and osteoarthritis outcome scores (KOOS), International Knee Documentation Committee (IKDC) score and Tegner activity level were recorded, and differential laxity was measured as the side-to-side difference in anterior tibial translation (ATT) using instrumented laximetry devices. Regression analyses were performed to determine associations between outcomes and meniscal and cartilage lesions as well as nine independent variables.

RESULTS

A total of 228 patients aged 54.8 ± 4.3 years at index ACLR were assessed at a follow-up of 14.3 ± 3.8 months. KOOS subcomponents were 85 ± 13 for symptoms, 91 ± 10 for pain, 75 ± 18 for daily activities, 76 ± 18 for sport, and 88 ± 12 for quality of life (QoL). The IKDC score was A for 84 (37%) knees, B for 96 (42%) knees, C for 29 (13%) knees, and D for 8 (4%) knees. Tegner scores showed a decrease (median 0, range -4 to 4) and differential laxity also decreased (median - 4, range - 23.5 to 6.0). KOOS symptoms worsened with higher BMI (p = 0.038), for women (p = 0.007) and for knees that had medial meniscectomy (p = 0.029). KOOS pain worsened with higher BMI (p ≤ 0.001), for women (p = 0.002) and for knees with untreated (p = 0.047) or sutured (p = 0.041) medial meniscal lesions. Differential laxity increased with follow-up (p = 0.024) and in knees with lateral cartilage lesions (p = 0.031).

CONCLUSION

In primary ACLR for patients aged over 50 years, female gender and medial meniscal lesions significantly compromised KOOS symptoms and pain, while lateral cartilage lesions significantly increased differential laxity. Compared to knees with an intact medial meniscus, those with sutured or untreated medial meniscal lesions had worse pain, while those in which the medial meniscus was resected had worse symptoms. These findings are clinically relevant as they could help surgeons with patient selection and adjusting expectations according to their functional demands.

LEVEL OF EVIDENCE

III.

Delayed anterior cruciate ligament reconstruction increases the incidence of medial meniscal bucket handle tears and medial compartment chondral injuries in patients aged 40 years and older

INTRODUCTION

No widely accepted evidence-based indications exist for the initial surgical management of patients with anterior cruciate ligament (ACL) injuries ≥ 40 years old, and treatment for these patients remains controversial. This study aimed to evaluate the association between elapsed time from ACL injury to surgery and the incidence of meniscal tears and chondral injury in patients aged ≥ 40 years.

MATERIALS AND METHODS

The patients who underwent primary ACL reconstruction were divided into two groups based on elapsed time from injury to surgery: early group, < 12 months; and delayed group, ≥ 12 months. Patient records were reviewed for incidence and types of meniscal tears and chondral injuries in each group. Chondral injury grades were evaluated with International Cartilage Regeneration and Joint Preservation Society (ICRS) Criteria.

RESULTS

This study evaluated 67 knees in the early group and 33 knees in the delayed group. Mean ages in each group were 46.9 ± 6.5 and 46.9 ± 6.0. The delayed group showed significantly higher rates of medial meniscal tear [31 of 33, 93.9% vs 29 of 67, 43.3%; P < 0.0001; odds ratio (OR), 20.31; 95% confidence interval (CI), 4.49-91.9], medial femoral condyle chondral injuries ≥ ICRS grade II (15 of 33, 45.5% vs 8 of 67, 11.9%; P < 0.001; OR, 6.15; 95% CI 2.24-16.83), and medial tibial chondral injuries ≥ ICRS grade II (7 of 33, 21.2% vs 3 of 67, 4.5%; P < 0.05; OR, 5.74; 95% CI 1.38-23.9) compared with the early group. With respect to types of medial meniscal tear, the delayed group showed a significantly higher frequency of bucket handle tears (11 of 33, 33.3%) compared with the early group (2 of 67, 3.0%; P < 0.0001; OR, 16.25; 95% CI 3.34-79.1).

CONCLUSIONS

Delayed ACL reconstruction was associated with increased incidence of chondral injuries and medial meniscal tears, particularly bucket handle tears in this cohort.

LEVEL OF EVIDENCE

Level III.

Clinical Trial Registry Use in Orthopaedic Surgery Systematic Reviews

BACKGROUND

Results from systematic reviews and meta-analyses, which have the highest level of evidence (Level I), often drive clinical decision-making and health policy. Often, unpublished trial data are omitted from systematic reviews, raising concerns about the extent of the reliability and validity of results that have been drawn from systematic reviews. We aimed to determine the extent to which systematic review authors include searches of clinical trial registries for unpublished data when conducting systematic reviews in orthopaedic surgery.

METHODS

Systematic reviews and/or meta-analyses were gathered from the top 5 orthopaedic surgery journals based on the h5-index from Google Scholar Metrics. Systematic reviews that had been published in the Cochrane Database of Systematic Reviews, which requires the inclusion of a clinical trial registry search, served as controls. For the primary outcome, each systematic review from the top 5 orthopaedic journals was screened to determine whether the authors of each study searched for unpublished data in clinical trial registries. We then compared the rate of registry searches with those in the control group. For the secondary analysis, a search of ClinicalTrials.gov was performed for unpublished trial data for 100 randomized systematic reviews.

RESULTS

All 38 of the Cochrane systematic reviews (100%) included clinical trial registry searches, while the top 5 orthopaedic journals had only 31 of 480 studies (6.5%) that looked at clinical trial registries. The secondary analysis yielded 59 of 100 systematic review articles (59.0%) that could have included unpublished clinical trial data from ≥1 studies to their sample.

CONCLUSIONS

Systematic reviews that have been published in the top orthopaedic surgery journals seldom included a search for unpublished clinical trial data.

CLINICAL RELEVANCE

The exclusion of clinical trial registry searches potentially contributes to publication bias within the orthopaedic literature. Moving forward, systematic review authors should include clinical trial registry searches for unpublished clinical trial data to provide the most accurate representation of the available evidence for systematic reviews and meta-analyses.

Hamstrings substitution via anteromedial portal with optional anterolateral ligament reconstruction is the preferred surgical technique for anterior cruciate ligament reconstruction: a survey among ESSKA members

PURPOSE

The objective of this study was to report on a worldwide web-based survey among the ESSKA community developed to investigate current recommendations regarding ACL reconstruction surgical procedures.

METHODS

All contacts in the official mailing list of the ESSKA were contacted to investigate preferences regarding graft type, anterolateral ligament reconstruction, femoral tunnel drilling technique, single-bundle vs double-bundle technique, femoral and tibial fixation methods.

RESULTS

Eight-hundred and twenty responses were analyzed. Hamstrings autograft was the graft of choice in male patients for 634 (79%) and in female patients for 674 (84%) responders, while its preference for ACL reconstruction in professional athletes was for 401 (50%). 480 (63%) surgeons surveyed would include anterolateral ligament reconstruction only if diagnosed and remaining instability after ACL surgery or revision. 598 (75%) respondents were in favor of anteromedial portal for femoral tunnel drilling. The most popular femoral fixation technique was found to be cortical suspension (500-66%), while a compression system was preferred on the tibial side by 537 (71% of the sample).

CONCLUSIONS

This survey study found that HT autograft, single-bundle reconstruction, anteromedial portal for femoral tunnel drilling, cortical suspension systems for femoral fixation and compression systems for tibial fixation represent the current standard of ACLR in a large community of orthopedic surgeons. The present study performed with surgeons who are members of the ESSKA community will help to comprehend the actual ACLR worldwide practice patterns. Due to low response rate, these results should be interpreted with caution and not to be intended to represent the state of the art of ESSKA community.

LEVEL OF EVIDENCE

III.

Rates of Concomitant Meniscal Tears in Pediatric Patients With Anterior Cruciate Ligament Injuries Increase With Age and Body Mass Index

Background

Anterior cruciate ligament (ACL) tears are frequently associated with meniscal injury. Risk factors for concomitant meniscal injuries have been studied in the adult population but less so in pediatric patients.

Purpose

To evaluate the relationship between age and body mass index (BMI) and the presence of a concomitant meniscal tear at the time of ACL reconstruction (ACLR) in pediatric patients.

Study Design

Case-control study; Level of evidence, 3.

Methods

A single-institution retrospective review was performed of patients aged <19 years who underwent primary ACLR over a 3.5-year period. Revision ACLR and multiligament knee reconstructions were excluded. Logistic regression was used to identify risk factors associated with having a meniscal tear at the time of surgery. Subgroup analysis was performed for medial and lateral meniscal tears.

Results

Included in this study were 453 patients (230 males, 223 females; median age, 15 years). Of these, 265 patients (58%) had a meniscal tear, including 150 isolated lateral meniscal tears, 53 isolated medial meniscal tears, and 62 patients with both lateral and medial meniscal tears. Median time from injury to surgery was 48 days. For every 1-year increase in age, there was a 16% increase in the adjusted odds of having any meniscal tear (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.05-1.27; P = .002), with a 20% increase in the odds of having a medial meniscal tear (OR, 1.20; 95% CI, 1.07-1.35; P = .002) and a 16% increase in the odds of having a lateral meniscal tear (OR, 1.16; 95% CI, 1.05-1.27; P = .003). For every 2-point increase in BMI, there was a 12% increase in the odds of having any meniscal tear (OR, 1.12; 95% CI, 1.02-1.22; P = .016) and a 10% increase in the odds of having a lateral meniscal tear (OR, 1.10; 95% CI, 1.01-1.19; P = .028).

Conclusion

Pediatric patients undergoing ACLR had a 58% incidence of concomitant meniscal pathology. Increasing age and BMI were independent risk factors for these injuries, while no association was found between time to surgery and meniscal pathology.

Incidence of Medial and Lateral Meniscal Tears After Delayed Anterior Cruciate Ligament Reconstruction in Pediatric Patients

Background:

The treatment of pediatric anterior cruciate ligament (ACL) injuries is controversial, and no clear management guidelines have been established.

Purpose:

To evaluate the association between elapsed time from ACL injury to surgery and the incidence of meniscal tears and chondral injuries in patients aged ≤16 years.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Between December 2012 and April 2019, a total of 207 consecutive knees in 207 patients aged ≤16 years underwent primary ACL reconstruction and were included in this study. Patients were divided into 1 of 2 groups (early group [≤150 days] and delayed group [>150 days]) based on the time between injury and surgery. Patient records, including arthroscopic findings identified by 2 experienced knee surgeons at the time of surgery, were reviewed for demographic information, incidence and types of medial and lateral meniscal tears, and chondral injuries and their locations in each group.

Results:

There were 180 knees in the early group and 27 knees in the delayed group. The delayed group showed a significantly higher rate of medial meniscal tears than the early group: 16 of 27 (59.2%) and 46 of 180 (25.6%), respectively (odds ratio [OR], 4.24 [95% CI, 1.83-9.33]; P = .0011). The delayed group had a significantly lower rate of lateral meniscal tears than the early group: 6 of 27 (22.2%) and 90 of 180 (50.0%), respectively (OR, 0.29 [95% CI, 0.11-0.70]; P = .007). The delayed group had significantly higher rates of chondral injuries in the medial femoral condyle and the medial tibial plateau than the early group: 8 of 27 (29.6%) and 25 of 180 (13.9%), respectively (OR, 2.61 [95% CI, 1.03-6.62]; P = .049), and 2 of 27 (7.4%) and 1 of 180 (0.6%), respectively (OR, 14.32 [95% CI, 1.58-208.10]; P = .045).

Conclusion:

Delayed ACL reconstruction was associated with an increased incidence of medial chondral injuries and medial meniscal tears but with a decreased incidence of lateral meniscal tears.

Revision ACL Reconstruction in Adolescent Patients

Background:

High failure rates have been documented after anterior cruciate ligament reconstruction (ACLR) in pediatric patients, and revision surgery is indicated due to high activity levels of children and adolescents.

Purpose:

To define trends in revision ACLR in patients who underwent initial ACLR at younger than 18 years.

Study Design:

Case series; Level of evidence, 4.

Methods:

An electronic medical record was used to retrospectively identify revision ACLR procedures performed by 2 surgeons between the years 2010 and 2016 in patients younger than 18 years at initial reconstruction. Descriptive information, intraoperative findings, surgical techniques, and rehabilitation data were recorded from initial and revision surgeries. Descriptive statistics were used.

Results:

A total of 32 patients (17 girls, 15 boys) met the inclusion criteria, with a mean age of 15.8 years at initial reconstruction. For initial reconstructions, 15 patients underwent transphyseal procedures, 3 patients underwent adult-type procedures using an anatomic reconstruction technique that did not take into account the physis, and 2 patients underwent partial intraepiphyseal procedures. Graft types included hamstring autograft (n = 17), allograft (n = 5), hybrid (n = 4), and bone–patellar tendon–bone autograft (BTB; n = 3). Average primary reconstruction graft diameter was 8.0 mm (girls, 7.72 mm; boys, 8.36 mm; P = .045). After initial reconstruction, 10 patients had postoperative protocol noncompliance, and 8 patients reported delayed recovery. Mean time to retear was 565 days (range, 25-1539 days). At revision, BTB autograft was used in 50% (n = 16), followed by hamstring autograph (31.3%; n = 10) and allograft (12.5%; n = 4); mean graft diameter was 9.05 mm. Chondral surgery was more common during revision (25% for revision vs 0% for index; P = .031). There were 4 patients who required staged reconstruction with bone grafting. At mean final follow-up of 29.5 months (SD, 22.2 months), there were 3 graft failures (9.4%) and 5 contralateral ACL ruptures (15.6%).

Conclusion:

Most patients with ACL graft failure were adequately treated with a single revision. Conversion from a soft tissue graft to a BTB autograft was the most common procedure. Infrequently, patients required staged reconstructions. Providers should have a high index of suspicion for associated intra-articular injuries resulting from graft failure in adolescent patients.

Is There a Role for Cartilage Imaging in Athletes?

This article reviews implications for cartilage imaging in athletes in the setting of (1) acute chondral injury diagnosis, (2) evaluation and follow-up of conservative and surgical therapy, and (3) evaluation of cartilage as a surrogate for meniscal function and joint stability. Focal knee cartilage defects are common in athletic populations. Athletes with articular cartilage injury may initially be able to return to sport with conservative therapy; however, a reduction of athletic ability and progression to osteoarthritis is expected in athletes with untreated severe chondral injury. For diagnostic and pre- and postsurgical evaluation purposes, morphological magnetic resonance (MR) assessment of the articular cartilage with high-resolution protocols is crucial. Although not widely implemented for clinical use, compositional MR techniques have great potential for monitoring the development and progression of biochemical and microstructural changes in cartilage extracellular matrix before gross morphological changes occur.

An Up-to-Date Review of the Meniscus Literature: A Systematic Summary of Systematic Reviews and Meta-analyses

Background:

A large number of systematic reviews and meta-analyses regarding the meniscus have been published.

Purpose:

To provide a qualitative summary of the published systematic reviews and meta-analyses regarding the meniscus.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic search of all meta-analyses and systematic reviews regarding the meniscus and published between July 2009 and July 2019 was performed with PubMed, CINAHL, EMBASE, and the Cochrane database. Published abstracts, narrative reviews, articles not written in English, commentaries, study protocols, and topics that were not focused on the meniscus were excluded. The most pertinent results were extracted and summarized from each study.

Results:

A total of 332 articles were found, of which 142 were included. Included articles were summarized and divided into 16 topics: epidemiology, diagnosis, histology, biomechanics, comorbid pathology, animal models, arthroscopic partial meniscectomy (APM), meniscal repair, meniscal root repairs, meniscal allograft transplantation (MAT), meniscal implants and scaffolds, mesenchymal stem cells and growth factors, postoperative rehabilitation, postoperative imaging assessment, patient-reported outcome measures, and cost-effectiveness. The majority of articles focused on APM (20%), MAT (18%), and meniscal repair (17%).

Conclusion:

This summary of systematic reviews and meta-analyses delivers surgeons a single source of the current evidence regarding the meniscus.

ACL injuries before 15 years of age: could the young become an athlete?

PURPOSE

The purpose of this study was to systematically assess the possibility for a patient younger than 15 to return to a competitive level of sport following an ACL injury.

METHODS

Four databases were analyzed (PubMed, MedLine, Cinahl, Cochrane Library and LISTA). The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were used to guide the screening of the literature. Studies about functional and surgical treatments were included with a minimum of 5 years of mean follow-up. Methodological quality of individual studies was assessed with the Methodological Index for Non-Randomized Studies scale.

RESULTS

Ten studies were included, corresponding to a total of 217 patients. All studies were retrospective with level 4 evidence. Seven studies reported results of a transphyseal technique reconstruction, two studies a physeal-sparing reconstruction, and one studied the results of a repair (« healing response »). Only one study compared functional treatment and surgery. The mean age of patients at the time of surgery was 12.29 years (range 2-16) with a mean follow-up of 7.9 years (range 5.5-18.3). Return to sport was possible for 80 to 100% of patients (average of 91.7%) at the final follow-up but the level for return to sport was reported in only four studies and found between 61 and 89% for return to the same level and at 42% for return to a competitive level. Evolution of the Tegner score was analyzed in five studies and was reported to decrease at the follow-up in three studies. ACL re-ruptures can be considered as failure of the graft (nine studies with surgical technique) and occurred with an average of 16%.

CONCLUSION

This review demonstrate that ACL reconstruction is superior to conservative treatment and 'healing response' in terms of revision rates and knee laxity. Return to sport is possible for more than 4/5 of patients but only two thirds of them were able to return to the same level or to competitive level, and failure rates of the graft were not superior to global population. However, qualities of included studies and variability of treatment limited the clinical application of results. Despite this, patients and parents should be informed that ACL injuries are lesions that may influence the level of sport at a 5-year follow-up.

LEVEL OF EVIDENCE

Level IV, systematic review.

All-epiphyseal anterior cruciate ligament reconstruction produces good functional outcomes and low complication rates in pediatric patients: a systematic review

PURPOSE

To assess the literature on indications, outcomes, and complications in pediatric patients undergoing all-epiphyseal (AE) anterior cruciate ligament reconstruction (ACLR).

METHODS

PubMed, Medline, and Embase were searched for literature evaluating AE ACLR in pediatric patients. All included studies were assessed for quality using the Methodological Index for Non-Randomized Studies (MINORS). Descriptive statistics are presented where applicable.

RESULTS

Overall, 17 studies comprising 545 patients, with a mean age of 12.0 ± 1.2 (range 8-19) met the inclusion criteria. The graft choices in this systematic review included hamstring tendon autografts (75.4%, n = 403), quadriceps tendon autograft (6.2%, n = 33), Achilles tendon allograft (3.6%, n = 19) and posterior tibialis tendon allograft in one patient (0.2%, n = 1). Time of return-to-sport ranged from 8 to 22 months. Postoperative subjective IKDC scores were above 90 points. The rate of return-to-sport after AE ACLR was 93.2% (n = 219/235) and 77.9% (n = 142/183) of patients returned to sport at pre-injury level. The overall complication rate was 9.8% (n = 53/545) with the most common complication being ACL re-rupture (5.0%; n = 27/545). Only 1.5% (n = 8/545) of patients demonstrated growth disturbances.

CONCLUSION

Overall, the AE ACLR technique can achieve good postoperative functional outcomes while notably minimizing the incidence of primary issue of physeal disruption and potential associated leg-length discrepancies. AE ACLR should be considered in pediatric patients with at least 2 years of skeletal growth remaining based on radiographic bone age to minimize the impact of growth-related complications.

LEVEL OF EVIDENCE

IV (Systematic Review of Level III and IV evidence).

Physeal Sparing Anterior Cruciate Ligament Reconstruction in Skeletally Immature Patients Bridging the Tibial Physis With Two Divergent Tunnels

A technique for anterior cruciate ligament (ACL) reconstruction in patients with open physis is presented. The patient is positioned supine with the knee flexed 90°. After intraarticular injuries are addressed, an autologous hamstring graft is harvested and prepared using a suspension device attached in its expansion device. All-epiphyseal femoral and tibial tunnels of the same diameter of the graft are created; both of them are drilled in an outside-in direction, sparing the physis under radioscopic control. A second divergent tibial tunnel of the same diameter of the graft, distal to the physis, is created in an outside-in, mediolateral, and craniocaudal direction, leaving a 1-cm bone bridge between the 2 tibial tunnels. The graft is passed through the all-epiphyseal tunnels, from femoral to tibial, and pulled until the suspension device leans on the lateral femoral cortex. The graft is passed through the second divergent tibial tunnel and fixed in it with an interference screw to move the pressure away from the physis.

One in 5 Athletes Sustain Reinjury Upon Return to High-Risk Sports After ACL Reconstruction: A Systematic Review in 1239 Athletes Younger Than 20 Years

CONTEXT

Anterior cruciate ligament (ACL) reconstruction (ACLR) is frequently performed in patients younger than 20 years whose goal is to return to sport (RTS). Varying reinjury rates have been reported, and the factors responsible are unclear. Studies differ with regard to age, graft type, surgical techniques, postoperative rehabilitation, RTS guidelines, and methods used to determine ACL failures.

OBJECTIVE

To determine RTS rates; the effect of participation in high-risk sports, sex, and graft type on ACL reinjury rates; and whether objective test criteria before RTS correlate with lower reinjury rates.

DATA SOURCES

A systematic review of the literature from inception to May 31, 2019, was conducted using the PubMed and Cochrane databases.

STUDY SELECTION

Studies on transphyseal ACLR in athletes <20 years old with a minimum mean follow-up of 2 years that reported reinjury rates, the number that RTS, and detailed the type of sport were included.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

A total of 1239 patients in 8 studies were included; 87% returned to sport and 80% resumed high-risk activities. Of the patients, 18% reinjured the ACL graft and/or the contralateral ACL. Nine percent of patellar tendon autografts and 15% of hamstring autografts failed (odds ratio [OR], 0.52; P = 0.002). Of reinjuries, 90% occurred during high-risk sports. Male patients had a significantly higher rate of ACL graft failure than female patients (OR, 1.64; P = 0.01). There was no sex-based effect on contralateral ACL injuries. Only 1 study cited objective criteria for RTS.

CONCLUSION

A high percentage of athletes returned to sport, but 1 in 5 suffered reinjuries to either knee. Male patients were more likely to reinjure the ACL graft. Objective criteria for RTS were rarely mentioned or not detailed. The need for testing of knee stability, strength, neuromuscular control, agility, and psychological measures before RTS remains paramount in young athletes.

Anterior Cruciate Ligament Reconstruction in Patients Older Than 50 Years: A Systematic Review and Meta-analysis

Background:

There is no consensus regarding the best treatment approach for middle-aged patients with anterior cruciate ligament (ACL) injuries. Chronic ACL-deficient knees are often associated with instability as well as secondary meniscal and cartilage lesions. ACL reconstruction (ACLR) has achieved satisfactory outcomes in younger patients; however, the effectiveness and safety of ACLR in middle-aged patients remain uncertain.

Purpose:

To compare the patient-reported functional scores, arthrometric outcomes, and complications of primary ACLR between older (≥50 years) and younger (<50 years) patients.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

We conducted a systematic review of cohort studies that compared the clinical outcomes of ACLR between patients aged ≥50 years and those aged <50 years. The Cochrane Central Register of Controlled Trials, Embase, and MEDLINE databases were searched for relevant studies. The Methodological Index for Non-randomized Studies (MINORS) criteria was used to assess the risk of bias and conducted a random-effects meta-analysis to combine the data, and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to evaluate the overall quality of the body of retrieved evidence. The primary outcome was knee functional outcomes, and secondary outcomes were arthrometric outcomes of ACLR and complications.

Results:

This study included 4 retrospective cohort studies with a total of 287 participants (129 in the older group and 158 in the younger group). All included studies reported significant improvements in clinical outcomes in both groups after ACLR. No significant differences were noted in the improvement of International Knee Documentation Committee (IKDC) scores (mean difference [MD], 0.20 [95% CI, −2.65 to 3.05]; P = .89) and Lysholm scores (MD, −1.98 [95% CI, −6.93 to 2.98]; P = .43) between the 2 groups. No significant differences were observed in anteroposterior stability or risk of complications between the groups.

Conclusion:

ACLR may be performed in middle-aged patients (≥50 years) without concern for inferior clinical and arthrometric results compared with younger patients (<50 years).

Anterior Cruciate Ligament Reconstruction Within 3 Weeks Does Not Increase Stiffness and Complications Compared With Delayed Reconstruction: A Meta-analysis of Randomized Controlled Trials

BACKGROUND

Injury-to-surgery time has been identified as a key point in anterior cruciate ligament (ACL) reconstruction, with early versus delayed treatment remaining a debated and controversial topic in the management of ACL tears.

PURPOSE/HYPOTHESIS

The aim was to quantitatively synthesize the best literature evidence by including only randomized controlled trials (RCTs) comparing early versus delayed ACL reconstruction, with a clear and univocal definition of cutoffs of early or delayed surgery. The hypothesis was that early treatment would lead to similar final clinical results compared with the delayed approach while providing a faster recovery without an increase in complications after ACL reconstruction.

STUDY DESIGN

Meta-analysis.

METHODS

A systematic literature search was performed on February 12, 2019, using PubMed, Web of Science, Cochrane Library, and gray literature databases. According to previous literature, 2 analyses with different cutoffs for injury-to-surgery time (3 weeks and 10 weeks) were performed to distinguish early and delayed reconstruction. The influence of timing was analyzed through meta-analyses in terms of patient-reported outcome measures (PROMs), risk of complications, range of motion (ROM) limitation, risk of retears, and residual laxity. Risk of bias and quality of evidence were assessed following the Cochrane guidelines.

RESULTS

Eight studies (5 in 3-week cutoff analysis and 3 in 10-week cutoff analysis) were included. No differences were found in terms of PROMs, risk of complications, ROM limitation, risk of retears, and residual laxity either in the 3-week cutoff analysis or in the 10-week cutoff analysis (P > .05). The level of evidence was moderate to low for the outcomes of the 3-week cutoff analysis and low to very low for the outcomes of the 10-week cutoff analysis.

CONCLUSION

This meta-analysis did not confirm the previously advocated benefits of delaying ACL surgery to avoid the acute posttraumatic phase. In fact, RCTs demonstrated that timing of surgery after ACL tears has no influence on the final functional outcome, risk of retears, or residual instability. While no data were available about the recovery time, literature results showed that early ACL reconstruction could be performed without increasing the risk of complications.

STUDY REGISTRATION

CRD42019119319 (PROSPERO).

Evidence too weak to guide surgical treatment decisions for anterior cruciate ligament injury: a systematic review of the risk of new meniscal tears after anterior cruciate ligament injury

OBJECTIVE

To investigate the risk of new meniscal tears after treatment for anterior cruciate ligament (ACL) injury, in children and adults with and without ACL reconstruction.

DESIGN

Prognosis systematic review (PROSPERO registration number CRD42016036788).

METHODS

We searched Embase, Ovid Medline, Cochrane, CINAHL, SPORTDiscus, PEDro and Google Scholar from inception to 3rd May 2018. Eligible articles included patients with ACL injury (diagnosis confirmed by MRI and/or diagnostic arthroscopy), reported the number of meniscal tears at the time of ACL injury diagnosis/start of treatment and reported the number of new meniscal tears that subsequently occurred. Articles with fewer than 20 patients at follow-up, and articles limited to ACL revision surgery or multi-ligament knee injuries were excluded. Two independent reviewers screened articles, assessed eligibility, assessed risk of bias and extracted data. We judged the certainty of evidence using the Grading of Recommendations Assessment Development and Evaluation (GRADE) working group methodology.

RESULTS

Of 75 studies included in the systematic review, 54 studies with 9624 patients and 501 new meniscal tears were appropriate for quantitative analysis. Heterogeneity precluded data pooling. The risk of new meniscal tears was 0%-21% when follow-up was <2 years, 0%-29% when follow-up was 2 to 5 years, 5%-52% when follow-up was 5 to 10 years and 4%-31% when follow-up was longer than 10 years. The proportion of studies with high risk of selection, misclassification and detection bias was 84%, 69% and 68%, respectively. Certainty of evidence was very low.

CONCLUSION

New meniscal tears occurred in 0%-52% of patients between 4 months and 20 years (mean 4.9±4.4 years) following treatment for ACL injury. The certainty of evidence was too low to guide surgical treatment decisions. This review cannot conclude that the incidence of new meniscal tears is lower if ACL injury is treated with surgery compared with treatment with rehabilitation only.

Acute ACL reconstruction shows superior clinical results and can be performed safely without an increased risk of developing arthrofibrosis

PURPOSE

To compare acute ACL reconstruction (ACLR) within 8 days of injury with delayed reconstruction after normalized range of motion (ROM), 6-10 weeks after injury. It was hypothesized that acute ACL reconstruction with modern techniques is safe and can be beneficial in terms of patient-reported outcomes and range of motion.

METHODS

The effect of acute and delayed ACLR was randomized studied on 70 patients with high recreational activity level, Tegner level 6 or more, between 2006 and 2013. Patient-reported outcomes, objective IKDC, KOOS, and manual stability measurements were documented during the 24-month follow-up period.

RESULTS

The acute ACLR group did not result in increased stiffness and showed superior outcome regarding strength and how the patient felt their knee functioning at 24 months. In addition, the acute group was not inferior to the delayed group in any assessment. Regarding patient-related outcomes in KOOS, both groups showed significant improvements in all subscales, but no difference was found between the groups. Functional return (FR) rate was almost double compared to the Swedish knee ligament register and treatment failure (TF) rate was reduced by half, no significant difference between the groups. No difference regarding cyclops removal, re-injury of ACL or meniscus was found between the two surgical timing groups.

CONCLUSION

Acute ACLR within 8 days of injury does not appear to adversely affect ROM or result in increased stiffness in the knee joint and was not inferior to the delayed group in any assessment when compared to delayed surgery.

LEVEL OF EVIDENCE

I.

Graft Fixation and Timing of Surgery Are Predictors of Early Anterior Cruciate Ligament Revision: A Cohort Study from the Swedish and Norwegian Knee Ligament Registries Based on 18,425 Patients

The identification of surgical risk factors for early anterior cruciate ligament (ACL) revision is important when appropriate treatment for patients undergoing primary ACL reconstruction is selected. The purposes of this study were to determine the short-term ACL revision rate of patients undergoing primary ACL reconstruction and to identify surgical risk factors for ACL revision within 2 years of primary ACL reconstruction.

Impact of Surgical Timing on Clinical Outcomes in Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction Using Hamstring Tendon Autografts

Background:

To date, no studies have analyzed the influence on clinical outcomes of the interval between an anterior cruciate ligament (ACL) injury and double-bundle (DB) reconstruction with hamstring tendon autografts.

Hypotheses:

(1) Performing ACL reconstruction sooner after an injury will reduce postoperative anterior and rotatory knee instability, (2) postoperative range of knee motion or functional results will not be affected by different intervals between injury and surgery, and (3) preoperative isokinetic peak torque of the quadriceps and hamstring muscles will be lower in patients undergoing surgery earlier, while postoperative muscle strength will not be affected by surgery timing.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

This study was conducted on a total of 171 patients who had undergone anatomic DB ACL reconstruction with hamstring tendon autografts. The patients were divided into 3 groups based on the time to surgery: (1) ≤1 month after the injury (group E; n = 25), (2) between 1 and 3 months after the injury (group M; n = 72), and (3) >3 months after the injury (group D; n = 74). Patients were assessed for a minimum of 2 years after surgery.

Results:

Concerning postoperative anterior laxity, 1-way analysis of variance demonstrated a significant difference (P = .0274) among the 3 groups. Anterior laxity was significantly less in group E than in group D (P = .0206). Spearman rank correlation analysis showed a significant correlation (ρ = 0.200; P = .0327) between anterior knee laxity and time to surgery. Also, a significant correlation (P = .0461) was found between the degree of the pivot-shift phenomenon and time to surgery. There were no significant differences in loss of knee extension or flexion among the 3 groups, nor were there any differences in the Lysholm knee score or International Knee Documentation Committee grade. Postoperatively, there were no significant differences in peak torque of the quadriceps or hamstring muscles among the 3 groups.

Conclusion:

Early DB reconstruction led to significantly less anterior laxity compared with delayed reconstruction. There were no significant differences in postoperative range of knee motion or functional results among the 3 time intervals between injury and surgery in this study.

Rates of knee arthroplasty in anterior cruciate ligament reconstructed patients: a longitudinal cohort study of 111,212 procedures over 20 years

Background and purpose - Long-term rates of knee arthroplasty in patients with anterior cruciate ligament (ACL) injury who undergo ligament reconstruction (ACLr) are unclear. We determined this risk of arthroplasty through comparison with the general population.Patients and methods - All patients undergoing an ACLr in England, 1997-2017, were identified from national hospital statistics. Patients subsequently undergoing a knee arthroplasty were identified and survival analysis was performed (survival without undergoing knee arthroplasty). A Cox proportional hazards model was used to identify factors associated with knee arthroplasty. Relative risk of knee arthroplasty (total or partial) in comparison with the general population was determined.Results - 111,212 ACLr patients were eligible for analysis (mean age 29; 77% male). Overall, 0.46% (95% confidence interval [CI] 0.40-0.52) ACLr patients underwent knee arthroplasty within 5 years, 0.97% (CI 0.82-1.2) within 10 years, and 1.8% (CI 1.4-2.3) within 15 years. Knee arthroplasty risk was greater in older age groups and women. In comparison with the general population, the relative risk of undergoing arthroplasty at a younger age (at time of arthroplasty) was elevated: at 30-39 years (risk ratio [RR] 20; CI 11-35), 40-49 years (RR 7.5; CI 5.5-10), and 50-59 years (RR 2.5; CI 1.8-3.5), but not 60-69 years (RR 1.7; CI 0.93-3.2).Interpretation - Patients sustaining an ACL injury who undergo ACLr are at elevated risk of subsequent knee arthroplasty in comparison with the general population. Although the absolute rate of arthroplasty is low, the risk of arthroplasty at a younger age is particularly elevated. When the outcome of shared decision-making is ACLr, this data will help inform patients and clinicians about the long-term risk of requiring knee arthroplasty.