Anterior Cruciate Ligament Injury at the Time of Anterior Tibial Spine Fracture in Young Patients: An Observational Cohort Study

Maturation-dependent patterns of knee injuries among symptomatic pediatric soccer players on MRI

OBJECTIVE

To systematically investigate the prevalence of knee MRI findings among symptomatic pediatric soccer players with respect to skeletal maturity and to identify predictors of surgery.

METHODS

This IRB-approved, HIPAA-compliant retrospective study included soccer players (< 18 years of age) who underwent MRI examinations in the past 5 years (2018-2023). Two radiologists retrospectively and independently reviewed all examinations to categorize skeletal maturity and to identify osseous and soft tissue findings. Findings were compared between maturation groups, and logistic regression models were used to identify predictors of surgery.

RESULTS

Ninety-seven players (45 boys, 52 girls) included 39 skeletally immature, 21 maturing, and 37 mature knees. Kappa coefficient for interobserver reliability ranged between 0.65 and 1.00. Osgood-Schlatter disease (OSD) was more common among immature than maturing and mature knees (25% vs 14% and 5%, p = 0.04); anterior cruciate ligament (ACL) injury was more common among maturing and mature than immature knees (59% and 48%, vs 15%, p < 0.01); and meniscal tears were more common among mature than immature and maturing knees (medial, 41% vs 18% and 14%, p = 0.03; lateral, 43% vs 21% and 19%, p = 0.04). Players in the mature group were more likely to undergo surgery (p = 0.01). The presence of an effusion (OR = 19.5, 95% CI 2.8-240.9, p = 0.01), ACL injury (OR = 170.0, 95% CI 1.3-6996.9, p < 0.01), and lateral meniscal tears (OR = 10.8, 95% CI 1.8-106.1, p = 0.02) were independent predictors of surgery.

CONCLUSION

Differential patterns of injury were found among symptomatic pediatric soccer players; the presence of an effusion, ACL injury, and lateral meniscal tears were independent predictors of surgery, likely contributing to the higher rates of surgery among skeletally mature players.

Knee laxity after anterior tibial eminence fracture in children: A 35-case series

INTRODUCTION

Anterior tibial eminence (ATE) fractures are characterized by avulsion of the anterior cruciate ligament insertion. The aim of our study was to evaluate the long-term incidence of laxity and instability in the aftermath of these fractures. The secondary objective was to identify factors for instability.

HYPOTHESIS

ATE fracture in children is responsible for laxity and instability in the medium and long term.

MATERIAL AND METHODS

This retrospective, single-center study included 35 isolated fractures of the tibial intercondylar eminence during skeletal growth between January 2006 and January 2020. Analysis comprised demographics, laxity measured by GNRB™, range of motion and IKDC and Lysholm scores. Clinical reassessment was performed in 24 patients, the other 11 being interviewed by telephone.

RESULTS

Mean laxity on GNRB™ was 1.46mm, and 3 patients had>3mm differential with respect to the healthy knee. Mean IKDC score was 92.2 and mean Lysholm score 93.1. Four patients showed instability, 2 of whom required surgical management. There was no significant difference in occurrence of laxity according to fracture type or reduction quality. Mean follow-up was 5.9years (range, 1.1-14.8).

DISCUSSION

Our clinical and functional results were in accordance with the literature. The long-term clinical results were satisfactory. ATE fractures require long-term follow-up to screen for instability and laxity on GNRB™.

LEVEL OF EVIDENCE

IV, retrospective study.

Tibial spine fractures: State of the art

Tibial spine fractures (TSFs) are avulsion fractures at the site where the anterior cruciate ligament inserts onto the tibial eminence. TSFs typically affect children and adolescents aged 8-14 years. The incidence of these fractures has been reported to be approximately 3 per 100,000 per year, but the rising involvement of paediatric patients in sporting activities is increasing the number of these injuries. TSFs are historically classified on plain radiographs according to the Meyers and Mckeever classification system, which was introduced in 1959, but the renewed interest in these fractures and the increasing use of magnetic resonance imaging led to the recent development of a new classification system. A reliable grading protocol for these lesions is paramount to guide orthopedic surgeons in determining the correct treatment for young patients and athletes. TSFs can be addressed conservatively in the case of nondisplaced or reduced fractures or surgically in the case of displaced fractures. Different surgical approaches and, specifically, arthroscopic techniques have been described in recent years to ensure stable fixation while limiting the risk of complications. The most common complications associated with TSF are arthrofibrosis, residual laxity, fracture nonunion or malunion, and tibial physis growth arrest. We speculate that advances in diagnostic imaging and classifications, combined with greater knowledge of treatment options, outcomes, and surgical techniques, will likely reduce the occurrence of these complications in paediatric and adolescent patients and athletes, allowing them a timely return to sports and everyday activities.

Meniscal injuries in skeletally immature children with tibial eminence fractures. Systematic review of literature

PURPOSE

Although the mechanisms of injury are similar to ACL rupture in adults, publications dealing with meniscal lesions resulting from fractures of the intercondylar eminence in children are much rarer. The main objective was to measure the frequency of meniscal lesions associated with tibial eminence fractures in children. The second question was to determine whether there is any available evidence on association between meniscal tears diagnostic method, and frequencies of total lesions, total meniscal lesions, and total entrapments.

METHODS

A comprehensive literature search was performed using PubMed and Scopus. Articles were eligible for inclusion if they reported data on intercondylar tibial fracture, or tibial spine fracture, or tibial eminence fracture, or intercondylar eminence fracture. Article selection was performed in accordance with the PRISMA guidelines.

RESULTS

In total, 789 studies were identified by the literature search. At the end of the process, 26 studies were included in the final review. This systematic review identified 18.1% rate of meniscal tears and 20.1% rate of meniscal or IML entrapments during intercondylar eminence fractures. Proportion of total entrapments was significantly different between groups (17.8% in the arthroscopy group vs. 6.2% in the MRI group; p < .0001). Also, we found 20.9% of total associated lesions in the arthroscopy group vs. 26.1% in the MRI group (p = .06).

CONCLUSION

Although incidence of meniscal injuries in children tibial eminence fractures is lower than that in adults ACL rupture, pediatric meniscal tears and entrapments need to be systematically searched. MRI does not appear to provide additional information about the entrapment risk if arthroscopy treatment is performed. However, pretreatment MRI provides important informations about concomitant injuries, such as meniscal tears, and should be mandatory if orthopaedic treatment is retained. MRI modalities have yet to be specified to improve the diagnosis of soft tissues entrapments.

STUDY DESIGN

Systematic review of the literature REGISTRATION: PROSPERO N° CRD42021258384.

High Incidence of Soft Tissue Injury in Pediatric Proximal Tibia Fractures: A Systematic Review

Purpose

The purpose of this study was to describe the incidence of soft tissue injuries associated with pediatric proximal tibial fractures (PPTF) and the frequency that magnetic resonance imaging (MRI) was used before surgery in this patient population.

Methods

A systematic review of English literature, using EMBASE and PubMed, was completed. Articles reporting on soft tissue injury in PPTFs between 1980 and 2021 were identified. Associated pathology (meniscal tear, meniscal entrapment, cruciate ligament injury, extensor mechanism injury, and chondral injury) and use of MRI at time of diagnosis, were assessed in these studies. Twenty-three articles were included.

Results

Extraction of data revealed 1046 patients and 1057 fractures, with a mean age of 12.3 ± 1.7 at the time of injury. Most patients were male (n = 757 [72.3%]). Most fractures were tibial eminence fractures (TEF) (n = 747 [70.7%]), followed by tibial tubercle (n = 218 [20.6%]) and then tibial plateau fractures (n = 92 [8.7%]). Associated soft tissue injuries were found in 58.8% (n = 621) of fractures overall. Meniscal entrapment was the most common, occurring in 22.1% (n = 234) of cases. Meniscal tears occurred in 18.6% of cases (n = 197), followed by ligament injury in 9.4% (n = 99), chondral injury in 6.5% (n = 69), and extensor mechanism injury in 2.1% (n = 22) of cases. All cases of tendinous extensor mechanism injury were seen in tibial tubercle fractures, with 22 injuries occurring in 10.1% of tibial tubercle fractures. At time of injury just 24.3% (n = 257) of fractures had an MRI performed before surgery.

Conclusions

PPTFs are associated with a high incidence of associated injury (58.8%), particularly in TEFs (63.5%) and TPFs (100%).

Level of Evidence

Systematic Review of Level III-IV studies.

Fixation Strategy Does Not Affect Risk of Growth Disturbance After Surgical Treatment of Pediatric Tibial Spine Fracture

Purpose

To characterize growth abnormalities after surgical treatment of tibial spine fractures and to investigate risk factors for these abnormalities.

Methods

A retrospective analysis of children who underwent treatment of tibial spine fractures between January 2000 and January 2019 was performed, drawing from a multicenter cohort among 10 tertiary care children's hospitals. The entire cohort of surgically treated tibial spine fractures was analyzed for incidence and risk factors of growth disturbance. The cohort was stratified into those who were younger than the age of 13 years at the time of treatment in order to evaluate the risk of growth disturbance in those with substantial growth remaining. Patients with growth disturbance in this cohort were further analyzed based on age, sex, surgical repair technique, implant type, and preoperative radiographic measurements with χ2, t-tests, and multivariate logistic regression.

Results

Nine patients of 645 (1.4%) were found to have growth disturbance, all of whom were younger than 13 years old. Patients who developed growth disturbance were younger than those without (9.7 years vs 11.9 years, P = .019.) There was no association with demographic factors, fracture characteristics, surgical technique, hardware type, or anatomic placement (i.e., transphyseal vs physeal-sparing fixation) and growth disturbance.

Conclusions

In this study, we found an overall low incidence of growth disturbance after surgical treatment of tibial spine fractures. There was no association with surgical technique and risk of growth disturbance.

Level of Evidence

Level III, retrospective comparative study.

Imaging the pediatric anterior cruciate ligament: not little adults

An increased incidence of anterior cruciate ligament (ACL) injuries in children over the last few decades has led to a corresponding increase in ACL reconstruction procedures in children. In this review, we will illustrate unique features seen when imaging the ACL in children versus adults. After briefly reviewing relevant normal ACL anatomy, we will review imaging findings of congenital ACL dysplasia. This is followed by a discussion of imaging ACL avulsions. Lastly, we will review the different types of ACL reconstruction procedures performed in skeletally immature children and their post-operative appearances.

MRI findings of growth plate fractures of the knee: are there age- and fracture-dependent differences?

OBJECTIVE

To investigate MRI findings in children with physeal fractures of the knee with respect to age, location, and articular involvement.

METHODS

Children with physeal fractures who underwent knee MRI between 2008 and 2021 were included. Two radiologists retrospectively reviewed all examinations to determine articular involvement, findings of physeal instability (perichondral disruption, periosteal entrapment), and internal derangement (cruciate ligament injury, meniscal tear, chondromalacia). Independent samples t, Mann-Whitney U, Pearson's chi-square, and Fisher's exact tests were used to compare findings.

RESULTS

Fifty-six patients (37 boys, 19 girls; mean age: 12.2 ± 2.5 years; 32 distal femur, 24 proximal tibial fractures) included 24(43%) intraarticular fractures. Fractures were more common in the tibia than the femur (67% versus 25%, p = 0.004) and intraarticular fractures were more common in older than younger children (13.1 ± 2.0 versus 11.5 ± 2.7 years, p = 0.01), to associate with chondromalacia (46% versus 12%, p = 0.02) and undergo surgery (33% versus 10%, p = 0.04) when compared to extraarticular fractures. Perichondral disruption (n = 44, 79%) and periosteal entrapment (n = 13, 23%) did not significantly differ based on location or articular involvement (p > 0.05). At a median follow-up of 17.5 months (interquartile range: 1.25-34), 3 patients (2 intraarticular, 1 extraarticular fractures) developed osteoarthritis, osteochondral lesion, and leg-length discrepancy from growth arrest, which required additional surgery.

CONCLUSION

Intraarticular physeal fractures were more common with older children, associate with chondromalacia, and underdo surgical intervention when compared to extraarticular fractures of the knee. While MRI findings of physeal instability were common, no significant differences were found between fractures based on anatomic location or fracture pattern.

Isolated ACL Reconstruction Versus ACL Reconstruction Combined With Lateral Extra-articular Tenodesis: A Comparative Study of Clinical Outcomes in Adolescent Patients

BACKGROUND

Young patients undergoing anterior cruciate ligament (ACL) reconstruction (ACLR) are at a particularly high risk of graft ruptures compared with adults. Recent studies have demonstrated significant reductions in ACL graft rupture rates in high-risk adult populations when a lateral extra-articular procedure is performed, but comparative studies in pediatric and adolescent populations are currently lacking in the literature.

PURPOSE/HYPOTHESIS

The purpose of this study was to compare the clinical outcomes of isolated ACLR versus combined ACLR and lateral extra-articular tenodesis (LET) when using the Arnold-Coker modification of the MacIntosh procedure in early adolescent patients. The hypothesis was that combined procedures would be associated with a significantly reduced risk of graft ruptures.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective analysis of consecutive early adolescent patients who underwent ACLR using a hamstring tendon autograft with or without the Arnold-Coker modification of the MacIntosh procedure was conducted. Patients with ≥1 additional risk factors for a graft rupture were offered LET in addition to ACLR (pivot-shift grade 2 or 3, high level of sporting activity defined as Tegner activity score ≥7, participation in pivoting sports, and Segond fractures). Clinical outcomes including graft rupture rates, patient-reported outcome measure scores (Knee injury and Osteoarthritis Outcome Score and subjective International Knee Documentation Committee), knee stability, return-to-sports rates, reoperation rates, and complications were assessed. Comparisons between variables were assessed with the chi-square or Fisher exact test for categorical variables and the Student or Wilcoxon test for quantitative variables. Multivariate analyses were undertaken to evaluate risk factors for a graft rupture.

RESULTS

A total of 111 patients with a mean follow-up of 43.8 ± 17.6 months (range, 24-89 months) were included in the study; 40 patients underwent isolated ACLR, and 71 underwent ACLR + LET. The addition of LET to ACLR was associated with a significantly lower graft rupture rate compared with isolated ACLR (0.0% vs 15.0%, respectively; odds ratio, 15.91 [95% CI, 1.81-139.44]; P = .012). It was also associated with significantly better knee stability (pivot-shift grade 3: 0.0% vs 11.4%, respectively; P = .021) (side-to-side anteroposterior laxity difference >5 mm: 0.0% vs 17.1%, respectively; P = .003) and Tegner activity scores (7 vs 6, respectively; P = .010). There were no significant differences between the groups regarding the Patient Acceptable Symptom State for the patient-reported outcome measures, nor for any of the other outcome measures evaluated, and no differences in the rate of non-graft rupture related reoperations or complications. The ACLR + LET group exceeded the minimal clinically important difference with respect to the Tegner activity scale.

CONCLUSION

In a retrospective comparative cohort study of adolescents, combined ACLR and LET was associated with a significantly lower graft rupture rate and no difference in non-graft rupture related reoperations or complications compared with isolated ACLR.

MRI evaluation of pediatric tibial eminence fractures: comparison between conventional and "CT-like" ultrashort echo time (UTE) images

OBJECTIVE

UTE MRI offers a radiation-free alternative to CT for bone depiction, but data on children is lacking. The purpose of this study was to determine whether UTE images improve detection and characterization of pediatric tibial eminence fractures.

METHODS

Fifteen MRIs with UTE from 12 children (10 boys, 2 girls; mean age: 12.6 ± 3.3 years) with tibial eminence fractures (2018-2020) and 15 age-matched MRIs without fractures were included. After randomization, 5 readers reviewed images without and with UTE, at least 1 month apart, and recorded the presence of fracture and preferred images. If fracture is present, radiologists also recorded fragment size, number, and displacement; surgeons assigned Meyers-McKeever grade and management. Disagreements on management were resolved through consensus review. Kappa and intra-class correlation (ICC), sensitivity, and specificity were used to compare agreement between readers and fracture detection between images without and with UTE.

RESULTS

For fracture detection, inter-reader agreement was almost perfect (κ-range: 0.91-0.93); sensitivity and specificity were equivalent between images without and with UTE (range: 95-100%). For fracture characterization, UTE improved agreement on size (ICC = 0.88 to 0.93), number (ICC = 0.52 to 0.94), displacement (ICC = 0.74 to 0.86), and grade (ICC = 0.92 to 0.93) but reduced agreement on management (κ = 0.68 to 0.61), leading to a change in consensus management in 20% (3/15). Radiologists were more likely to prefer UTE for fracture and conventional images for non-fracture cases (77% and 77%, respectively, p < 0.001).

CONCLUSION

While UTE did not improve diagnosis, it improved agreement on characterization of pediatric tibial eminence fractures, ultimately changing the preferred treatment in 20%.

Incidence of anterior tibial spine fracture among skiers does not differ with age

PURPOSE

Injury to the anterior cruciate ligament (ACL) is common in alpine skiing in the form of either an intra-substance ACL tear or anterior tibial spine fracture (ATSF). Anterior tibial spine fractures are typically reported in children. However, several case reports describe these injuries in adults while skiing. The purpose of this study is to describe the sport specific incidence of ATSF in alpine skiing.

METHODS

The study was conducted over a 22-year period. Skiers who suffered an ATSF were identified and radiographs were reviewed to confirm the diagnosis. Additionally, control data from intra-substance ACL injury groups were collected. The incidence of these injuries in children, adolescents, and adults (grouped as ages 0-10, 11-16, and 17 + years old, respectively) was evaluated and the risk factors for ATSF versus ACL tear were determined.

RESULTS

There were 1688 intra-substance ACL and 51 ATSF injuries. The incidence of intra-substance ACL injury was greater in adults (40.0 per 100,000 skier days) compared to the adolescent (15.4 per 100,000) and child (1.1 per 100,000) age groups. In contrast, the incidence of ATSF was similar in the adult (0.9 per 100,000), adolescent (1.9 per 100,000), and child (1.9 per 100,000) age groups. Loose ski boot fit was identified as a risk factor for ATSF.

CONCLUSION

The incidence of ATSF in alpine skiers is similar among all age groups. However, the incidence of intra-substance ACL injuries is far greater in adult skiers compared to adolescents and children. Risk factors for ATSF relate to compliance between the foot/ankle and the ski boot.

LEVEL OF EVIDENCE

III.

Reliability and Validity of an MRI-Based Knee Sagittal Alignment Measure in a Pediatric Cohort

BACKGROUND

Magnetic resonance imaging (MRI) sagittal alignment is a measure that has been described and validated in the adult population as a means of distinguishing normal knees from those with anterior cruciate ligament (ACL) injury, but this measure has not been formally assessed among pediatric patients. The purpose of this study was to (1) assess the reliability of this MRI-based measure in a pediatric cohort, and (2) validate its ability to distinguish between ACL and non-ACL-injured knees in this population.

METHODS

A consecutive series of knee MRI examinations performed at our center were reviewed to identify studies of pediatric patients (1) with ACL injury, and (2) without significant pathology. Patient age, sex, physeal status (open, closing, or closed), knee laterality, and magnet strength (1.5 or 3-Tesla) were collected. The sagittal alignment was measured in both medial and lateral tibiofemoral compartments using a previously described method. Mean anterior tibial translation was then calculated for each study. Inter-rater and intrarater reliability testing was performed on a subset of randomly-selected patients from each cohort by three raters by calculating intraclass correlation coefficients. Sagittal alignment measurements of all patients were then completed by a single author after reliability was confirmed. The medial and lateral compartment translation and mean anterior tibial translation measurements of normal and ACL-injured knees were compared.

RESULTS

Inclusion criteria were met by 131 studies: 86 from uninjured knees (normal cohort) and 45 knees with ACL injury (ACL cohort). Studies were performed at a mean age of 13.4 with a near equivalent sex distribution. Inter-rater and intrarater reliability were good to excellent for all measures for patients in both normal and ACL cohorts. Normal and ACL-injured knees demonstrated a significant difference in anterior tibial translation in all measured regions. The mean anterior tibia translation for ACL-injured knees was 2.01 mm (95% confidence interval: 1.03-2.98) versus -0.44 mm (95% confidence interval: -0.89-0.014).

CONCLUSION

This study identified good to excellent inter-rater and intrarater reliability of knee sagittal alignment measurements among pediatric patients. It also demonstrated a significant difference in medial compartment, lateral compartment, and mean tibial translation in patients with and without ACL injury, validating previous findings demonstrated in adult cohorts. These findings may be useful in assisting providers in the confirmation of suspected ACL injury and insufficiency and guide operative management in cases of clinical uncertainty.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Pediatric Tibial Spine Fractures: Exploring Case Burden by Age and Sex

Background

Pediatric tibial spine fractures (TSFs) are a well-known clinical entity, but the epidemiology of these injuries is not fully understood. Further, there are limited data on outcomes after TSF treatment, specifically the proportion of patients requiring subsequent anterior cruciate ligament (ACL) reconstruction.

Purpose

To describe the distribution of TSF case burden by age and sex and to determine the proportion of patients undergoing subsequent ACL reconstruction or developing ACL insufficiency.

Study Design

Descriptive epidemiology study.

Methods

The Truven Health MarketScan database was queried to identify patients aged 7 to 18 years with TSFs between 2016 and 2018. Diagnosis and initial treatment (surgical vs nonoperative) were recorded based on database coding. Case burden by age and sex was calculated. The database, which includes longitudinal data, was then queried for subsequent diagnoses of ACL insufficiency as well as subsequent ACL reconstruction procedures performed among the patients.

Results

We found 876 cases of TSF, 71.3% of which were treated nonoperatively. The male to female ratio for case burden was 2.2:1. Cases peaked at age 13 to 14 years for boys and age 11 to 12 years for girls. Of all cases identified, 3.7% also had either a diagnosis code for ACL laxity entered in a delayed fashion into the database or a later procedure code for ACL reconstruction (considered together to represent "subsequent ACL insufficiency"). Only 15 subsequent ACL reconstructions (1.7% of cases) were found, all of which were among boys and 9 of which were among boys aged 13 to 14 years.

Conclusion

This longitudinal study is the largest epidemiological analysis of pediatric TSFs to date. We found low rates of subsequent ACL insufficiency and ACL reconstruction, with boys aged 13 to 14 years accounting for most of those cases. Rates of subsequent ACL reconstruction were lower than previously reported. Boys accounted for more than two times as many TSF cases as girls.

Tibial Spine Repair in the Pediatric Population: Outcomes and Subsequent Injury Rates

Purpose

To evaluate short- to mid-term outcomes after arthroscopic operative fixation of tibial spine fractures in pediatric patients, to determine the incidence of further ipsilateral and contralateral knee injuries, and to describe associated meniscal pathology and intraoperative findings at the time of tibial spine repair.

Methods

All patients under age 18 with a tibial spine fracture treated arthroscopically at 1 institution by 2 surgeons from 2008 through 2019 were identified by Current Procedural Terminology codes. Patients at least 1 year from their date of surgery were contacted to complete a questionnaire, which included the International Knee Documentation Committee (IKDC) form. Questions pertained to knee function, pain, and further injury or surgery on either knee. Patient charts, preoperative imaging, and operative reports were reviewed to determine demographic information, tibial spine fracture type, concomitant injuries, and intraoperative details.

Results

Sixty-six of 97 eligible patients (68%) completed questionnaires. Average age at initial surgery was 10.7 years (range, 4-17). Mean follow-up was 5.8 years (range, 1.0-11.9). Average IKDC score at follow-up was 91.4 (range, 62.1-100). Patients reported their knee as 92% of “normal” (range, 40-100). Thirty-five (53%) currently participate in sport; 6 (9%) remain limited because of instability and residual pain. Regarding pain on a visual analog scale, 94%, 95%, and 83% of patients reported less than a 3 at rest, with daily activity, and with sport, respectively. Seven patients (11%) had subsequent ACL rupture. Six patients (9%) underwent ACL reconstruction 3.1 years (range, 0.9-7) after initial repair. Fourteen patients (21%) required at least 1 additional procedure. Regarding the contralateral knee, there were no ACL or tibial spine injuries. Sixty-one (92%) patients were both satisfied and would definitely undergo the procedure again.

Conclusions

Although many pediatric patients demonstrate excellent results after tibial spine repair at mean 5.8 years follow-up, 10.6% sustained an ipsilateral ACL rupture, and 21% required an additional procedure. No patient had a contralateral tibial spine or ACL injury. This is helpful when counseling patients regarding injury risk when returning to activity after tibial spine repair.

Level of Evidence

Level IV, therapeutic case series.

Deep Learning-Based Magnetic Resonance Imaging Image Features for Diagnosis of Anterior Cruciate Ligament Injury

To study and explore the adoption value of magnetic resonance imaging (MRI) in the diagnosis of anterior cruciate ligament (ACL) injuries, a multimodal feature fusion model based on deep learning was proposed for MRI diagnosis. After the related performance of the proposed algorithm was evaluated, it was utilized in the diagnosis of knee joint injuries. Thirty patients with knee joint injuries who came to our hospital for treatment were selected, and all patients were diagnosed with MRI based on deep learning multimodal feature fusion model (MRI group) and arthroscopy (arthroscopy group). The results showed that deep learning-based MRI sagittal plane detection had a great advantage and a high accuracy of 96.28% in the prediction task of ACL tearing. The sensitivity, specificity, and accuracy of MRI in the diagnosis of ACL injury was 96.78%, 90.62%, and 92.17%, respectively, and there was no considerable difference in contrast to the results obtained through arthroscopy (P > 0.05). The positive rate of acute ACL patients with bone contusion and medial collateral ligament injury was substantially superior to that of chronic injury. Moreover, the incidence of chronic injury ACL injury with meniscus tear and cartilage injury was notably higher than that of acute injury, with remarkable differences (P < 0.05). In summary, MRI images based on deep learning improved the sensitivity, specificity, and accuracy of ACL injury diagnosis and can accurately determined the type of ACL injury. In addition, it can provide reference information for clinical treatment plan selection and surgery and can be applied and promoted in clinical diagnosis.

Acute Knee Injuries in Children and Adolescents: A Review

IMPORTANCE

Knee injuries in children and adolescents are exceedingly common. When an active youth presents complaining of knee pain, the treating pediatrician should be comfortable with forming a working differential diagnosis and should be able to manage many such injuries or recognize when it is necessary to make an appropriate referral.

OBSERVATIONS

Knee injuries typically present after acute trauma. Appreciating the likely etiologies pertaining to a particular case is best achieved with a thorough history and physical examination. This review discusses the etiologies of acute injuries including fractures that are unique to skeletally immature individuals, patellar dislocations, ligamentous injuries, and meniscal tears. Imaging findings and management of these conditions are also reviewed.

CONCLUSIONS AND RELEVANCE

This review summarizes the more common acute knee injuries seen in active children and adolescents. Given how frequently such conditions present, this overview of diagnosis and management will provide a useful resource for the nonspecialist.

Anterior Cruciate Ligament Tear Following Operative Treatment of Pediatric Tibial Eminence Fractures in a Multicenter Cohort

BACKGROUND

Postoperative ipsilateral anterior cruciate ligament (ACL) tears after tibial eminence fracture fixation has been previously noted in the literature. This study aims to describe the prevalence of and risk factors for postoperative ACL tears in a cohort of patients operatively treated for tibial eminence fracture.

METHODS

A retrospective review of children undergoing treatment of a tibial eminence fracture at 10 tertiary care children's hospitals was performed. The primary outcome of interest was subsequent ACL rupture. Incidence of ACL tear was recorded for the entire cohort. Patients who sustained a postoperative ACL tear were compared with those without ACL tear and analyzed for demographics and risk factors. A subgroup analysis was performed on patients with a minimum of 2-year follow-up data or those who had met the primary outcome (ACL tear) before 2 years.

RESULTS

A total of 385 pediatric patients were reviewed. 2.6% of the cohort experienced a subsequent ACL tear. The median follow-up time was 6.5 months (SD=6.4 mo). Subsequent ACL tears occurred at a median of 10.2 months (SD=19.5 mo) postoperatively. There was a statistically significant association with higher grade tibial spine fractures (Myers and McKeever type III and IV) and subsequent ACL tear (P=0.01). Patients with a subsequent ACL tear were older on average (13.5 vs. 12.2 y old), however, this difference was not statistically significant (P=0.08). Subgroup analysis of 46 patients who had a 2-year follow-up or sustained an ACL tear before 2 years showed a 21.7% incidence of a subsequent ACL tear. There was a statistically significant association with higher grade tibial spine fractures (Myers and McKeever type III and IV) and subsequent ACL rupture (P=0.006) in this subgroup. Postoperative ACL tears occurred in patients who were older at the time that they sustained their original tibial eminence fracture (13.4 vs. 11.3 y old, P=0.035).

CONCLUSIONS

Ipsilateral ACL tears following operatively treated pediatric tibial eminence fractures in a large multicenter cohort occurred at a rate of 2.6%. However, in those with at least 2 years of follow-up, the incidence was 21.7%. Subsequent ACL tear was more likely in those with completely displaced (type III or IV) tibial eminence fractures and older patients.

LEVEL OF EVIDENCE

Level III-retrospective cohort study.

Using the Remnant Anterior Cruciate Ligament to Improve Knee Stability: Biomechanical Analysis Using a Cadaveric Model

Background:

Injured anterior cruciate ligament (ACL) tissue retains proprioceptive nerve fibers, vascularity, and biomechanical properties. For these reasons, remnant ACL tissue is often preserved during the treatment of ACL injuries.

Purpose:

To assess through a cadaveric model whether reorienting and retensioning the residual ACL via an osteotomy improves knee stability after partial ACL tear, with substantial remnant tissue and intact femoral and tibial attachments.

Study Design:

Controlled laboratory study.

Methods:

In 8 adult cadaveric knees, we measured anterior tibial translation and rotational laxity at 30° and 90° of flexion with the ACL in its native state and in 3 conditions: partial tear, retensioned, and ACL-deficient. The partial-tear state consisted of a sectioned anteromedial ACL bundle.

Results:

In the native state, the translation was 10 ± 2.7 mm (mean ± SD) at 30° of flexion and 8.4 ± 3.6 mm at 90° of flexion. Anterior translation of the knees in the partial-tear state (14 ± 2.7 mm at 30° and 12 ± 2.7 mm at 90°) was significantly greater than baseline (P < .001 for both). Translation in the ACL-retensioned state (9.2 ± 1.7 mm at 30° and 7.2 ± 2.1 mm at 90°) was significantly less than in the ACL-deficient state (P < .001 for both), and translation was not significantly different from that of the intact state. For ACL-deficient knees, translation (20 ± 4.3 mm at 30° and 16 ± 4.4 mm at 90°) was significantly greater than all other states (P < .001 for all). Although rotational testing demonstrated the least laxity at 30° and 90° of flexion in the retensioned and intact states and the most laxity in the ACL-deficient state, rotation was not significantly different among any of the experimental states.

Conclusion:

In a cadaveric model of an incomplete ACL tear, a reorienting and retensioning core osteotomy at the tibial insertion of the remnant ACL improved anteroposterior translation of the knee without compromising its rotational laxity.

Clinical Relevance:

The findings of this study support the concept of ACL tissue reorienting and retensioning in the treatment of ACL laxity as an area for future investigation.

Management and Complications in Nonoperative Fractures of the Tibial Spine: A Systematic Review

Effective options exist for acute nonoperative management of anterior tibial spine fractures, yet there exists a paucity of literature describing long-term outcomes for these patients. This systematic review thus aims to consolidate management strategies and complications for patients with nonoperative anterior tibial spine fractures. In accordance with PRISMA guidelines, 5 databases (CINAHL, MEDLINE, EMBASE, Cochrane, and Pubmed) were searched and screened in duplicate. Quality assessment was performed using the Methodological Index for Non-Randomized Studies (MINORS) criteria. Of 485 studies identified in the initial search, a total of 18 studies involving 369 patients were eligible for this review. These were stratified into 173 type I, 124 type II, and 72 type III injuries as described by Meyers and McKeever. All patients were treated with knee immobilization in either full extension or slight flexion, with possible closed reduction and/or aspiration of hemarthrosis. Complications at final follow-up comprised 33.9% of patients with persistent stiffness, 19.4% persistent instability, 11.1% mechanical symptoms, 6.37 delayed anterior cruciate ligament reconstruction, 4.9% delayed operative intervention for other complications, and 1.9% extension impingement. Given the lack of comparative studies in this review, definitive conclusions for nonoperative management are difficult to establish on the basis of the current body of literature alone. A modestly higher rate of arthrofibrosis and persistent laxity are seen in higher-grade injuries, however, only a minority of studies stratified complications by Meyers and McKeever classification in this review. A better understanding of variables in treatment decision making require further prospective study focused on the collection of functional and patient-reported outcome measures, whereas also further delineating complications by injury severity.

Four Risk Factors for Arthrofibrosis in Tibial Spine Fractures: A National 10-Site Multicenter Study

BACKGROUND

Tibial spine fractures (TSFs) are relatively rare pediatric injuries. Postoperative arthrofibrosis remains the most common complication, with few studies having examined factors associated with its development.

PURPOSE

To identify risk factors for arthrofibrosis and required MUA or lysis of adhesions in the largest known cohort of patients with TSFs.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

This was a multicenter study of 249 patients ≤18 years old who had a TSF between January 2000 and February 2019. Patients were separated into cohorts based on whether they developed arthrofibrosis, defined as a 10° deficit in extension and/or 25° deficit in flexion at postoperative 3 months or a return to the operating room for manipulation under anesthesia (MUA) and/or lysis of adhesions.

RESULTS

A total of 58 (23.3%) patients developed postoperative arthrofibrosis, with 19 (7.6%) requiring a return to the operating room for MUA. Patients with arthrofibrosis were younger (mean ± SD, 11.3 ± 2.7 vs 12.3 ± 2.8 years; P = .029). They were more likely to have a nonsport, trauma-related injury (65.4% vs 32.1%; P < .001) and a concomitant ACL injury (10.3% vs 1.1%; P = .003). Those with arthrofibrosis had longer operative times (135.0 vs 114.8 minutes; P = .006) and were more likely to have been immobilized in a cast postoperatively (30.4% vs 16.6%; P = .043). In multivariate regression, concomitant anterior cruciate ligament (ACL) injury (odds ratio [OR], 20.0; P = .001), traumatic injury (OR, 3.8; P < .001), age <10 years (OR, 2.2; P = .049), and cast immobilization (OR, 2.4; P = .047) remained significant predictors of arthrofibrosis. Concomitant ACL injury (OR, 7.5; P = .030) was additionally predictive of a required return to the operating room for MUA.

CONCLUSION

Surgeons should be cognizant of arthrofibrosis risk in younger patients with concomitant ACL tears and traumatic injuries not resulting from athletics. Furthermore, postoperative immobilization in a cast should be avoided given the high risk of arthrofibrosis. Concomitant ACL injury is associated with a higher return to the operating room for MUA.