Pigmented villonodular synovitis/giant cell tumor in the knee.

PURPOSE OF REVIEW: Pigmented villonodular synovitis (PVNS) is a rare diagnosis in pediatric patients and commonly presents with symptoms of swelling and pain. Early diagnosis is important to prevent secondary degeneration into the subchondral bone. This review will analyze the etiology, clinical signs/symptoms, diagnosis, treatment, and recent literature on PVNS in the pediatric population. RECENT FINDINGS: Many theories of PVNS etiology have been described in the literature; however, an inflammatory response has been most widely accepted. PVNS can occur in any joint, but most commonly in the knee. The most common treatment for PVNS is synovectomy, and long-term follow-up is necessary to detect disease persistence or recurrence. SUMMARY: Although uncommon, PVNS does occur in the pediatric population and this diagnosis should be included in the differential of atraumatic joint swelling and pain.

Measurement of TT-TG can change with sequential MRIs due to variations in tibiofemoral rotation in patellofemoral instability patients.

PURPOSE: There are various anatomic risk factors for patellofemoral instability (PFI) that help guide surgical treatment, including the tibial tubercle to trochlear groove (TT-TG) distance. However, no study has analysed the temporal changes in TT-TG prior to surgical intervention. This study sought to understand the variations in TT-TG over time for pediatric patients suffering from PFI prior to surgical intervention. The authors hypothesised that the TT-TG would substantially change between time points. METHODS: Patients undergoing medial patellofemoral ligament (MPFL) reconstruction between 2014 and 2019 by one of two fellowship-trained orthopaedic surgeons were identified. Patients were included if they had two preoperative magnetic resonance imaging (MRI) performed on the same knee within 7.5 months of each other prior to any surgical intervention and had an initial TT-TG greater than 10 mm. RESULTS: After considering 251 patients for inclusion, 21 patients met the final inclusion criteria. The mean age was 14.5 ± 2.5 years and 61.9% were female. TT-TG was initially noted to be 15.1 ± 1.8 mm. At mean time after sequential MRIs of 5.0 ± 1.9 months, TT-TG was noted to be 16.7 ± 3.2 mm. The differences between initial and subsequent TT-TG ranged from a 21.2% decrease to a 61.1% increase, with a mean difference of an 11.3% increase. Comparison between initial and subsequent TT-TG values demonstrated a significant difference (p = 0.017). Change in tibiofemoral rotation ranged from -9.2° to 7.5°. When comparing the change in TT-TG to change in tibiofemoral rotation, a significant correlation was found (p = 0.019). CONCLUSION: Despite only a mean time between MRIs of 5 months, variations in TT-TG ranged from a decrease of 21.2% to an increase of 61.1%. The significant relationship between the changes in TT-TG and changes in tibiofemoral rotation between MRIs suggest that TT-TG measurements may vary due to variations in tibiofemoral rotation at the time of individual MRIs. LEVEL OF EVIDENCE: Level IV.

Simultaneous MPFL reconstruction and guided growth result in low rates of recurrent patellofemoral instability.

PURPOSE: Implant-mediated guided growth (IMGG) is used to address coronal plane deformity in skeletally immature patients. Few studies have reported on IMGG and simultaneous medial patellofemoral ligament (MPFL) reconstruction for paediatric patients with concurrent genu valgum and patellofemoral instability (PFI). This study aimed to report on the outcomes of these simultaneous procedures. MATERIALS AND METHODS: This was a retrospective review of paediatric patients undergoing simultaneous MPFL reconstruction and IMGG between 2016 and 2023. Mechanical lateral distal femoral angle (mLDFA), hip-knee-ankle angle (HKA) and mechanical axis deviation (MAD) were measured on full-length hip-to-ankle plain radiographs. Measurements were taken preoperatively, prior to implant removal and/or at final follow-up with minimum 1-year clinical follow-up. RESULTS: A total of 25 extremities in 22 patients (10 female) underwent simultaneous IMGG and MPFL reconstruction. The mean age at surgery was 12.6 ± 1.7 years. The mean duration of implant retention was 18.6 ± 11.3 months. Nineteen extremities (76%) underwent implant removal by final follow-up. Preoperative HKA corrected from a mean of 5.8 ± 2.3° to -0.8 ± 4.5° at implant removal or final follow-up (p < 0.001), with mLDFA and MAD similarly improving (both p < 0.001). HKA corrected a mean of 0.7 ± 0.9° per month, while mLDFA and MAD corrected a mean of 0.5 ± 0.6°/month and 2 ± 3 mm/month, respectively. At the time of implant removal or final follow-up, 88% of patients demonstrated alignment within 5° of neutral. Only one extremity experienced subsequent PFI (4%). For 14 patients who underwent implant removal with further imaging at a mean of 7.8 ± 4.9 months, only one patient (7%) had a valgus rebound to an HKA > 5°. CONCLUSION: Simultaneous MPFL reconstruction and IMGG provided successful correction of lower extremity malalignment with only one recurrence of PFI. This approach is a reliable surgical option for skeletally immature patients with genu valgum and PFI. LEVEL OF EVIDENCE: Level 4 case series.

Hemiepiphysiodesis for Genu Valgum in Patients With Multiple Hereditary Exostoses.

BACKGROUND: Genu valgum is a well-known feature of multiple hereditary exostoses (MHE). Though prior reports have demonstrated successful treatment with hemiepiphysiodesis, details regarding the correction rate and comparison to an idiopathic population are lacking. This study aimed to detail our institution's experience with guided growth of the knee in patients with MHE and compare this to an idiopathic population. METHODS: All pediatric patients (age 18 and younger) with MHE who underwent lower extremity hemiepiphysiodesis at a tertiary care medical center between January 2016 and December 2022 were retrospectively reviewed. Preoperative and postoperative mechanical lateral distal femoral angle (mLDFA) and medial proximal tibial angle (MPTA, the primary outcomes) were measured in addition to mechanical axis deviation (MAD) and hip-knee-ankle angle (HKA). Patients were 1:2 matched based on age, sex, and physes instrumented to a cohort with idiopathic genu valgum. RESULTS: A total of 21 extremities in 16 patients with MHE underwent hemiepiphysiodesis of the distal femur, proximal tibia, and/or distal tibia. The mean age at surgery was 11.7±2.2 years. Mean MAD corrected from zone 1.9±0.7 to -0.3±1.5, while mLDFA corrected from 83.4±2.9 to 91.7±5.2 degrees and MPTA corrected from 95.3±3.6 to 90.5±4.0 degrees in distal femurs and proximal tibias undergoing guided growth, respectively. Three extremities (14.3%) experienced overcorrection ≥5 degrees managed with observation. There were no differences in correction rates per month for mLDFA (0.54±0.34 vs. 0.51±0.29 degrees, P =0.738) or MPTA (0.31±0.26 vs. 0.50±0.59 degrees, P =0.453) between MHE and idiopathic groups. For 11 extremities in the MHE group with open physes at hardware removal, they experienced a mean recurrence of HKA of 4.0±3.4 degrees at 19-month follow-up. CONCLUSION: Hemiepiphysiodesis corrects lower extremity malalignment in patients with MHE at a similar rate compared with an idiopathic coronal plane deformity population. Rebound deformity of 4 degrees at 19 months after hardware removal in patients with remaining open growth plates should make surgeons conscious of the remaining growth potential when planning deformity correction. LEVEL OF EVIDENCE: Level III.

Growth modulation for angular knee deformities: a practical guideline.

PURPOSE OF REVIEW: This study aimed to review the established concepts and advances related to growth modulation for treating knee angular deformities. Although they are considered well tolerated procedures, careful indications and accurate techniques are necessary to ensure good results. RECENT FINDINGS: In addition to general clinical and radiographic evaluations, new tools such as two-dimensional low-dose radiography and gait analysis have been used to clarify angular and torsional combinations and the impact of mild angulations on the knee joint. Temporary epiphysiodesis is commonly the choice, and it can be performed with different implants such as staples, tension band plates (TBP), percutaneous transphyseal screws (PETS), sutures, and screws. SUMMARY: Considering its principles, TBP has been preferred for younger children. Cost can be a limitation, and research for alternative implants such as screws and nonabsorbable sutures indicate they might be an alternative in the future. In adolescents, PETS becomes an attractive alternative; however, its reversible character has been controversial, and further studies are needed to establish limits in younger patients.

Concomitant anterior medializing osteotomy and MPFL reconstruction improves patellar tilt when compared to MPFL reconstruction alone.

PURPOSE: Understanding how surgical procedures influence anatomic factors associated with patellofemoral instability can help guide surgeons when planning treatments for individual patients. This study sought to understand how patellar tilt is affected in adolescent patients with elevated pre-operative tibial tuberosity to trochlear groove (TT-TG) values undergoing medial patellofemoral ligament reconstruction (MPFLR) with or without an anterior medializing osteotomy (AMZ). METHODS: Utilizing a prospective database of 274 patellofemoral instability patients who underwent MPFLR ± AMZ by one of two orthopedic surgeons at a single institution, those who underwent MPFLR + AMZ were identified. Pre-operative and post-operative magnetic resonance imaging (MRI) were used to measure TT-TG distance, while radiographs were used to measure patellar tilt (tilt). Patients were matched based on age at surgery (within 2 years) and pre-operative TT-TG distance (within 2 mm) to a comparison cohort of patients who underwent isolated MPFLR (iMPFLR) without osseous procedures. RESULTS: A total of 56 patients were analyzed (28 per group). The mean age of the cohort was 15.5 ± 2.0 years and was similar between both groups (15.9 ± 1.9 versus 15.1 ± 2.0 years [n.s]). When comparing the two cohorts, significant pre- to post-operative decreases in patellar tilt for both MPFLR + AMZ (6.6 degrees, p < 0.001) and iMPFLR (3.9 degrees, p = 0.013) were noted. While there were no differences in pre-operative patellar tilt (21.2 ± 3.5 versus 21.1 ± 3.4 [n.s]), post-operatively, MPFLR + AMZ had significantly less patellar tilt than iMPFLR (13.2 ± 5.5 versus 16.5 ± 4.4, p = 0.017). CONCLUSIONS: This study found that patellar tilt significantly improved in participants undergoing either MPFLR + AMZ or iMPFLR. In addition, those undergoing MPFLR + AMZ were found to have significantly lower post-operative tilt than those undergoing iMPFLR. If patellar tilt is found pre-operatively to be significantly elevated and a risk for future dislocations, these findings suggest that surgeons might strongly consider MPFLR with AMZ to further address the increased tilt. LEVEL OF EVIDENCE: III.

Pediatric meniscus morphology varies with age: a cadaveric study.

PURPOSE: In adolescent patients, meniscal tear injury can occur either in isolation (e.g., discoid lateral meniscus tears) or in association with other traumatic injuries including tibial eminence fracture or ACL tear. Damage to meniscal integrity has been shown to increase contact pressure in articular cartilage, increasing risk of early onset osteoarthritis. In symptomatic patients failing conservative management, surgical intervention via meniscus repair or meniscus transplant is indicated. The purpose of this study was to evaluate the radial dimensions of pediatric menisci throughout development. The hypothesis was that the average radial meniscus dimensions will increase as specimen age increases, and mean medial and lateral region measurements will increase at a linear rate. METHODS: Seventy-eight skeletally immature knee cadaver specimens under age 12 years were included in this study. The meniscal specimens were photographed in the axial view with ruler in the plane of the tibial plateau and analyzed using computer-aided design (CAD) software (Autodesk Fusion 360). Measurements were taken from inner to outer meniscus rims at five 45 degree intervals using the clockface as a reference (12:00, 1:30, 3:00, 4:30, 6:00), and total area of meniscus and tibial plateau was recorded. Generalized linear models were used to evaluate the associations of radial width measurements with age, tibial coverage, and lateral vs. medial meniscus widths. RESULTS: All radial width measurements increased significantly with specimen age (p ≤ 0.002), and all lateral-medial meniscal widths increased (p < 0.001). The anterior zones of the meniscus were found to increase at the slowest rate compared to other regions. Tibial plateau coverage was found to not significantly vary with age. CONCLUSIONS: Meniscus radial width and lateral-medial meniscus width are related to age. The anterior width of the meniscus varied least with age. Improved anatomic understanding may help surgeons more effectively plan for meniscus repair, discoid resection/saucerization/repair, and also support appropriate selection of meniscus allograft for transplantation.

Higher Grit Scores Are Associated With Earlier Increases in Knee Flexion Following Anterior Cruciate Ligament Reconstruction With Meniscus Repair in Pediatric Patients.

BACKGROUND: The Grit Scale is used to measure grit, defined by Duckworth and colleagues as the disposition to show perseverance and passion for long-term goals. It has been shown that psychological factors like motivation, coachability, and coping with adversity are correlated with faster readiness for return to sport (RTS) in patients undergoing anterior cruciate ligament reconstruction (ACLR). This study investigates the association between pediatric patients' baseline grit scores and; preoperative Patient-reported Outcomes Measurement Information System (PROMIS) Pain scores and the recovery of range of motion (ROM) after ACLR. The investigators hypothesized that higher preoperative grit scores would predict lower preoperative pain scores and earlier return of knee ROM in patients undergoing ACLR. METHODS: This is a retrospective cohort study. Pediatric patients who underwent primary ACLR were assigned the pediatric Grit Scale. Patients were subdivided by meniscal procedures due to differences in postoperative protocols. ACLR alone or with meniscectomy (ACLR ± meniscectomy) were grouped together and ACLR with meniscal repair (ACLR + meniscus repair) represented the other cohort. Patients above the 50th grit percentile were considered "high grit". Patients below the 50th percentile were considered "low grit". Baseline PROMIS pain intensity and interference were collected. ROM was compared by grit cohort using the Mann-Whitney U test with a significance threshold of P ≤ 0.05. RESULTS: A total of 58 patients undergoing ACLR were analyzed: 20 ACLR ± meniscectomy and 38 ACLR + meniscus repair. The mean age was 15.0 ± 2.1 years with 41.4% of participants identifying as females. No significant difference was noted between baseline PROMIS pain intensity and interference and grit score ( P = 0.82, P = 0.91, respectively). Three months postoperatively, for those in the ACLR + meniscus repair cohort, low grit ROM was 130 degrees (interquartile range = 10 degrees), whereas high grit ROM was 135 degrees (interquartile range = 8 degrees) ( P = 0.006). CONCLUSIONS: This study found no differences in pain scores at presentation between grit cohorts but found that patients with grit scores below the 50th percentile undergoing ACLR + meniscus repair have 5 degrees less total ROM at 3 months compared with those with high grit scores. Quicker ROM recovery in patients with high grit may be a leading indicator of these patients' likelihood to achieve other postoperative milestones and meet criteria for RTS more quickly; the relationship between grit and readiness for RTS should be further investigated. LEVEL OF EVIDENCE: Level IV; retrospective cohort study.

Intrarater and Interrater Reliability of Radiographic Characteristics in Skeletally Immature Patients With Anterior Cruciate Ligament Tears: A PLUTO Study Group Reliability Study.

BACKGROUND: Radiographic measurements of limb alignment in skeletally immature patients with anterior cruciate ligament (ACL) tears are frequently used for surgical decision-making, preoperative planning, and postoperative monitoring of skeletal growth. However, the interrater and intrarater reliability of these radiographic characteristics in this patient population is not well documented. HYPOTHESIS: Excellent reliability across 4 raters will be demonstrated for all digital measures of length, coronal plane joint orientation angles, mechanical axis, and tibial slope in skeletally immature patients with ACL tears. STUDY DESIGN: Cohort study (diagnosis). METHODS: Three fellowship-trained orthopaedic surgeons and 1 medical student performed 2 rounds of radiographic measurements on digital imaging (lateral knee radiographs and long-leg radiographs) of skeletally immature patients with ACL tears. Intrarater and interrater reliability for continuous radiographic measurements was assessed with intraclass correlation coefficients (ICCs) across 4 raters with 95% CIs for affected and unaffected side measurements. Interrater reliability analysis used an ICC (2, 4) structure and intrarater reliability analysis used an ICC (2, 1) structure. A weighted kappa coefficient was calculated for ordinal variables along with 95% CIs for both interrater and intrarater reliability. Agreement statistic interpretations are based on scales described by Fleiss, and Cicchetti and Sparrow: <0.40, poor; 0.40 to 0.59, fair; 0.60 to 0.74, good; and >0.74, excellent. RESULTS: Radiographs from a convenience sample of 43 patients were included. Intrarater reliability was excellent for nearly all measurements and raters. Interrater reliability was also excellent for nearly all reads for all measurements. CONCLUSION: Radiographic reliability of long-leg radiographs and lateral knee x-rays in skeletally immature children with ACL tears is excellent across nearly all measures and raters and can be obtained and interpreted as reliable and reproducible means to measure limb length and alignment. LEVEL OF EVIDENCE: Level III.

Lateral-extra articular tenodesis vs. anterolateral ligament reconstruction in skeletally immature patients undergoing anterior cruciate ligament reconstruction.

PURPOSE OF REVIEW: The aim of this study was to review the most recent available evidence about lateral-extra articular tenodesis (LET) and anterolateral ligament (ALL) reconstruction in young patients treated for anterior cruciate ligament (ACL) injury. RECENT FINDINGS: The ALL of the knee acts as a secondary stabilizer of the knee preventing anterior translation and internal rotation. In vitro and in vivo biomechanical studies as well as prospective clinical trials have shown the importance of the ALL in knee biomechanics. The ALL injury has a synergetic impact on the knee stability in patients with acute ACL injury. ALL augmentation of ACL provides reduction of knee instability and graft failure and higher return to sport rates in high-risk patients. It has not been demonstrated that extra-articular procedures increase the risk of knee osteoarthritis secondary to knee over-constriction. Both Iliotibial band (ITB) ALL reconstruction and modified Lemaire LET have been shown safe and effective. Minimal biomechanical or clinical differences have been found between the two reconstruction methods. SUMMARY: Young patients with ACL tears and risk factors such as laxity or pivot shift willing to return to sports may benefit from ALL augmentation. Therefore, it is essential to identify these high-risk patients to individualize treatment.

Patellar instability: will my patella dislocate again?

PURPOSE OF REVIEW: The incidence of patellar instability in pediatric patients ranges is 50-100 in 100,000 patients per year. Risk of recurrent dislocations however has been cited from 8.6% to 88% depending on individual patient factors. This manuscript highlights the demographical, historical, and anatomic factors associated with recurrent patellar instability following a first-time patella dislocation in the pediatric population. RECENT FINDINGS: In recent years, various studies have focused on identifying risk factors for recurrent patellar instability following a primary patellar dislocation. A mix of patient factors, including age of first dislocation, patella alta, elevated tibial tubercle to trochlear groove and trochlear dysplasia have all been noted in the literature, which have helped to develop various scoring tools to predict recurrent dislocation following nonoperative treatment. SUMMARY: Risk of recurrent patellar instability in patients who have previously suffered a patellar dislocation can be due to many factors. These risk factors should be used and applied to a variety of risk scores in order to provide physicians and healthcare providers with a tool to counsel patients and families on their patellar redislocation risk and help guide further management.

Many Radiographic and Magnetic Resonance Imaging Assessments for Surgical Decision Making in Pediatric Patellofemoral Instability Patients Demonstrate Poor Interrater Reliability.

PURPOSE: To evaluate the interrater reliability of several common radiologic parameters used for patellofemoral instability and to attempt to improve reliability for measurements demonstrating unacceptable interrater reliability through consensus training. METHODS: Fifty patients with patellar instability between the ages of 10 and 19 years were selected from a prospectively enrolled cohort. For measurements demonstrating unacceptable interrater reliability (intraclass correlation coefficient [ICC]: <0.6), raters discussed consensus methods to improve reliability and re-examined a subset of 20 images from the previous set of images. If reliability was still low after the second round of assessment, the measure was considered unreliable. RESULTS: Of the 50 included subjects, 22 (44%) were male and the mean age at the time of imaging was 14 ± 2 years. With 1 or fewer consensus training sessions, the interrater reliability of the following radiograph indices were found to be reliable: trochlea crossing sign (ICC: 0.625), congruence angle (ICC: 0.768), Caton-Deshamps index (ICC: 0.644), lateral patellofemoral angle (ICC: 0.768), and mechanical axis deviation on hip-to-ankle alignment radiographs (ICC: 0.665-0.777). Reliable magnetic resonance imaging (MRI) indices were trochlear depth (ICC: 0.743), trochlear bump (ICC: 0.861), sulcus angle (ICC: 0.684), patellar tilt (ICC: 0.841), tibial tubercle to trochlear groove distance (ICC: 0.706), effusion (ICC: 0.866), and bone marrow edema (ICC: 0.961). CONCLUSIONS: With 1 or fewer consensus training sessions, the interrater reliability of the following patellofemoral indices were found to be reliable for trochlear morphology: trochlea crossing sign and congruence angle on radiograph and trochlear depth, trochlear bump, and sulcus angle on MRI. Reliable patellar position measurements included: Caton-Deshamps index and lateral patellofemoral angle on radiograph and patellar tilt and tibial tubercle to trochlear groove distance on MRI. Additional global measurements (e.g., mechanical axis deviation on standing radiographs) and MRI assessments demonstrated acceptable reliability. LEVEL OF EVIDENCE: II, prospective diagnostic study.

Improved epiphyseal socket placement with intraoperative 3D fluoroscopy: a consecutive series of pediatric all-epiphyseal anterior cruciate ligament reconstruction.

PURPOSE: Disturbance of the growth plate during all-epiphyseal anterior cruciate ligament reconstruction (ACLR) socket placement is possible due to the undulation of the distal femoral physis and proximal tibial physis. Therefore, it is important to obtain intraoperative imaging of the guide wire prior to reaming the socket. The purpose of this study was to investigate the effect of the use of 3D intraoperative fluoroscopy on socket placement in patients undergoing all-epiphyseal ACLR. It was hypothesized that 3D imaging would allow for more accurate intraoperative visualization of the growth plate and hence a lower incidence of growth plate violation compared to 2D imaging. METHODS: Patients under the age of 18 who underwent a primary all-epiphyseal ACL reconstruction by the senior authors and had an available postoperative MRI were retrospectively reviewed. Demographic data, surgical details, and the distances between the femoral socket and distal femoral physis (DFP) and tibial socket and proximal tibial physis (PTP) were recorded. Patients were split into two groups based on type of intraoperative fluoroscopy used: a 2D group and a 3D group. Interrater reliability of radiographic measurements was evaluated using intraclass correlation coefficient (ICC). RESULTS: Seventy-two patients fit the inclusion criteria and were retrospectively reviewed. 54 patients had 2D imaging and 18 patients had 3D imaging. The mean age at time of surgery was 12.3 ± 1.5 years, 79% of patients were male, and 54% tore their left ACL. The mean time from surgery to postoperative MRI was 2.0 ± 1.1 years. The ICC was 0.92 (95% CI 0.35-0.98), indicating almost perfect interrater reliability. The mean difference in distance between the tibial socket and the PTP was significantly less in the 2D imaging group than the 3D imaging group (1.2 ± 1.7 mm vs 2.5 ± 2.2 mm, p = 0.03). The femoral and tibial sockets touched or extended beyond the DFP or PTP, respectively, significantly less in the 3D group than in the 2D group (11% vs 43%, p < 0.000, 17% vs 65%, p < 0.000). CONCLUSION: There was a significantly increased distance from the PTP and decreased incidence of DFP violation with use of 3D intraoperative imaging for all-epiphyseal ACLR socket placement. Surgeons should consider utilizing 3D imaging prior to creating femoral and tibial sockets to potentially decrease the risk of physis violation in these patients. LEVEL OF EVIDENCE: III.

Osteogenesis imperfecta: treatment and surgical management.

PURPOSE OF REVIEW: Osteogenesis imperfecta is a disease with many different causes and clinical presentations. Surgery at a young age is the often required in order to improve the patients' growth development and quality of life. This manuscript highlights the current approach to treat children with osteogenesis imperfecta. The main purpose of this review is to compare and discuss the latest surgical techniques and procedures. RECENT FINDINGS: Recent studies have indicated that telescoping intramedullary Faisser-Duval rods are one of the most suitable surgical devices to correct long bone deformities. The design permits elongation with growth and helps reduce the number of revision surgeries compared to previous static devices. SUMMARY: Osteogenesis imperfecta patients require an interdisciplinary and tailored treatment that involves both medical and surgical components. On the basis of the most recent surgical and medical findings, the authors recommend treating osteogenesis imperfecta patients early with bisphosphonates prior to surgical intervention and then utilizing Faisser-Duval rods in a surgical setting to correct lower extremity deformities and fractures.

Increased tibiofemoral rotation on MRI with increasing clinical severity of patellar instability.

PURPOSE: Tibiofemoral rotation through the knee joint, specifically relative external tibial rotation, has been identified as a potential contributing factor to patellar instability. The purpose of this study is to investigate the relationship between severity of instability with degree of tibiofemoral rotation in three clinical cohorts: fixed or obligatory dislocators (in which the patella either is constantly laterally dislocated or laterally dislocates with every instance of knee flexion, respectively), standard traumatic instability patients, and normal controls. METHODS: A retrospective study was performed with three cohorts from April 2009 to February 2019: fixed or obligatory dislocators, standard traumatic instability patients, and controls with normal magnetic resonance imaging (MRI) of the knee. All fixed or obligatory dislocation patients from the study time frame were analyzed; controls and standard traumatic instability patients were randomly selected. Inclusion criteria were age under 18 years and qualifying diagnosis; exclusion criteria were outside institution MRI and previous MPFL reconstruction or tibial tubercle osteotomy. Tibiofemoral rotation was measured blindly on initial axial MRI using the posterior femoral and tibial condylar lines. Tibial tubercle to trochlear groove distance (TT-TG) was measured. Intraclass correlation coefficient (ICC) was calculated among four measurers. RESULTS: A total of 100 patients were included, 20 fixed or obligatory dislocators, 40 standard traumatic instability patients, and 40 controls. Median age was 13.2 years (range 10-17 years), with 55 females. Age was significantly higher in the standard traumatic instability group than both the control (p < 0.001) and fixed or obligatory dislocator groups (p = 0.003). ICC for TT-TG and tibiofemoral rotation were 0.92 and 0.96, respectively. Fixed or obligatory dislocator patients averaged 8.5° external tibiofemoral rotation, standard traumatic instability patients 1.6° external tibiofemoral rotation, and controls 3.8° internal tibiofemoral rotation. Both tibiofemoral rotation and TT-TG were highest in the fixed or obligatory dislocator cohort, followed by the standard traumatic instability cohort, and lowest in the controls (p < 0.0001 for tibiofemoral rotation and TT-TG). Multivariate analysis showed no correlation between age and tibiofemoral rotation. CONCLUSIONS: Measurement of tibiofemoral rotation was reproducible with excellent interrater reliability. The degree of tibiofemoral rotation is correlated with severity of patellar instability, with the greatest external tibiofemoral rotation in fixed or obligatory dislocator patients, followed by standard traumatic instability patients, and slight internal tibiofemoral rotation in controls. High external tibiofemoral rotation may be an important pathoanatomic factor in fixed or obligatory dislocators, and with further understanding may become a prognostic factor or surgical target. LEVEL OF EVIDENCE: III.

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.

Osgood-Schlatter disease: a 2020 update of a common knee condition in children.

PURPOSE OF REVIEW: Osgood-Schlatter disease (OSD) is one of the most common causes for anterior knee pain in children and adolescents resulting from a traction apophysitis of the tibial tubercle. While a peak in boys aged 12-15 years old was well documented, there seems to be no difference in sex distribution nowadays. This may result from increased participation of young females in high-impact sports. This review provides an up-to-date account on contemporary prophylaxis as well as diagnostic and therapeutic approaches. RECENT FINDINGS: Numerous studies have examined risk factors for OSD. These include body weight, muscle tightness, muscle weakness during knee extension and flexibility of hamstring muscles. In particular, shortening of the rectus femoris may substantially alter biomechanical functions of the knee. Conservative management remains successful in over 90% of patients. However, if disabling symptoms and pain persistent after physeal closure, operative treatment may be necessary. SUMMARY: OSD is a mostly self-limiting apophysitis of the tibial tubercle and the adjacent patella tendon in young active patients with open physis. Prevention strategies include quadriceps and hamstring stretching and therefore should be implemented in everyday practice routines for children who partake in regular sports activities.

Magnetic resonance evaluation of the pediatric knee after arthroscopic fixation of osteochondral lesions with biodegradable nails.

PURPOSE: To use magnetic resonance imaging (MRI) to investigate the knee joint of children following arthroscopic fixation of osteochondral lesions using bioabsorbable nails and to correlate these imaging findings with time from arthroscopic treatment and with risk factors at the time of imaging. MATERIALS AND METHODS: Our study included postarthroscopic MRI studies from 58 children (mean age at arthroscopy, 13.8 + 2.1 years) who have undergone bioabsorbable nail fixation of unstable osteochondral lesions between February 1, 2011 and September 30, 2017. All studies were retrospectively reviewed for broken nails, intra-articular debris, and internal knee derangement. Demographic information and information pertaining to active symptoms was obtained from both MRI questionnaire that was completed at the time of the study and clinical note that preceded the study. Marginal logistic regression models estimated using generalized estimating equations (GEE) were used to identify factors associated with a broken nail and joint effusion. RESULTS: A total of 104 postoperative studies were reviewed, which included 60 with symptoms and 44 without symptoms. Nail breakage was present in 38 (36.6%) studies and associated with presence of symptoms (OR 2.43, p = 0.036) and effusion (OR 2.76, p = 0.025). An effusion was present in 40 (38.5%) studies which decreased with increasing time from treatment (OR 0.89, p = 0.007) and increased with symptoms (OR 10.87, p < 0.001). Meniscal tear was present on 8 (7.7%) and chondral irregularity on 14 (13.5%) studies. CONCLUSION: Broken nail, effusion, and less commonly, meniscal tears and chondral irregularity, are all complications that can arise following fixation of osteochondral lesions with bioabsorbable nails. MRI can serve as a valuable tool in assessing these complications.

Normal Glenoid Ossification in Pediatric and Adolescent Shoulders Mimics Bankart Lesions: A Magnetic Resonance Imaging-Based Study.

PURPOSE: The purpose of this descriptive study was to define patterns of ossification and fusion of growth centers around the pediatric and adolescent glenoid as a function of age using 3-dimensional, frequency-selective, fat-suppressed spoiled gradient recalled echo magnetic resonance (MR) imaging sequences, with a particular focus on the anterior glenoid rim because of its clinical relevance as a potential confounder of glenohumeral instability. METHODS: Picture Archiving and Communication System records at an urban academic tertiary care orthopaedic facility from October 2005 to December 2018 were queried for shoulder MRI in patients aged 9 to 17 years. Patients were excluded if they had any diagnoses that could alter glenoid development. All images were independently evaluated by a musculoskeletal fellowship-trained radiologist. Secondary ossification centers were characterized as cartilage anlage, ossified, or fused at 3 anatomic sites: the anterior glenoid rim, coracoid, and superior glenoid rim. RESULTS: A total of 250 MR examinations (143 males, 107 females) were assessed in this study. The glenoid develops in a predictably sequential manner with ossification at the anterior glenoid rim lagging behind the coracoid and superior glenoid rim. The earliest age of anterior glenoid rim ossification was 11 years for both males (range 11-17) and females (range 11-12). Anterior glenoid rim ossification peaked at age 16 among males (34.8%, 8/23) and age 11 among females (27.3%, 3/11). CONCLUSIONS: Glenoid ossification and fusion progress in a predictable and chronological manner. This pattern should be used as a guideline when interpreting pediatric shoulder MRI examinations. In particular, an anterior glenoid ossification center should not be confused with an anterior glenoid injury (e.g., Bankart lesion), particularly in males 11 to 17 years old and females 11 to 12 years old. LEVEL OF EVIDENCE: IV (case series).

Juvenile Osteochondritis Dissecans of the Trochlea: A Cohort Study of 34 Trochlear Lesions Associated With Sporting Activities That Load the Patellofemoral Joint.

BACKGROUND: Juvenile osteochondritis dissecans (JOCD) lesions are rarely located in the trochlea and few studies have focused on the causes and outcomes of JOCD lesions in this part of the knee. The purpose of this study is to (1) evaluate the clinical characteristics and outcomes of patients who undergo surgery for JOCD in this unusual location as well as (2) assess the association between trochlear JOCD and participation in sporting activities that load the patellofemoral joint. METHODS: We conducted a retrospective cohort study of 34 trochlear JOCD lesions in 30 patients. Cases that involved traumatic cartilage shear or patella instability were excluded. Preoperative and postoperative magnetic resonance images and x-rays were evaluated and demographic data, sports played, comorbidities, surgical procedures, and clinical data were extracted from medical records. A case-control cohort of 102 femoral condyle lesions was used to assess the correlation between sports played and lesion location. RESULTS: The cohort comprised 34 consecutive trochlear JOCD lesions in 30 patients (26 males, 4 females). Average age at surgery was 13.8 years (9.3 to 18.0 y). In total, 27 (90%) patients were active, and of these active patients, soccer and basketball were the most common sports played. In the case-control comparison, the correlation between playing either basketball or soccer and the presence of a trochlear JOCD lesion was statistically significant (P=0.017). In total, 21 knees (62%) received operative treatment. Sixteen of the surgical patients underwent repair and fixation with bioabsorbable nails. The average length of clinical and radiographic follow-up was 21.1 months. All patients who underwent fixation showed radiographic and/or clinical indications of healing at most recent follow-up. Thirteen of the patients who underwent fixation were active, and all of these patients reported successful return to sports. Thirteen knees underwent nonoperative treatment, and the majority of these patients had limited follow-up. CONCLUSIONS: We report a significant association between pediatric athletes who play basketball and soccer and the development of trochlear JOCD, suggesting that repetitive loading of the patellofemoral joint may play a role in the development of JOCD lesions. Patients with trochlear JOCD lesions were likely to undergo surgery, and repair and fixation of the lesions produced good outcomes at short-term follow-up. LEVEL OF EVIDENCE: Level III-case-control study.