Distal Femoral Epiphysis Research Articles

T2-weighted spoiled gradient echo MRI for forensic age estimation: a study on knee growth plates.

The timing of growth plate fusion is a key indicator for age estimation and is primarily used in forensic investigations. On the other hand, non-ionizing techniques such as MRI are being developed to provide safer and more ethical evaluations in forensic casework. This study aims to evaluate the closure process of growth plates in the distal femoral and proximal tibial epiphyses using Multiple Echo Recombined Gradient Echo (MERGE) MRI sequences and provide age estimation data based on staging methods for forensic purposes. We retrospectively analyzed 559 patients (294 males, 265 females, aged 8-25 years) diagnosed with trauma and knee pain at Tepecik Training and Research Hospital from 2016 to 2019. MRI scans were performed using a 1.5-T system with MERGE sequences and evaluated by two observers using a new staging system. Observer agreement was assessed using Cohen's κ test, yielding high agreement values (κ > 0.8). Positive correlations were found between age and ossification stages (p < 0.001). Minimum age thresholds for stages 5a and 5b of the distal femoral epiphysis were 16 and 18 years for females and 17 and 19 years for males, respectively. For the proximal tibial epiphysis, the minimum ages for stages 5a and 5b were 15 years for females and 17 years for males. The MERGE sequence provides a viable method for assessing skeletal maturity in living individuals with significant ethical advantages due to non-ionizing radiation. This study supports the potential application of the MERGE sequence in forensic age estimation, demonstrating high observer agreement and consistency. Future research should focus on comparing different sequences and populations to enhance the methodology's applicability.

Poster 278: Low Distal Femoral Epiphysis Height May Be a Risk Factor for Growth Disturbance Following All-inside All-Epiphyseal Anterior Cruciate Ligament Reconstruction

Poster 278: Low Distal Femoral Epiphysis Height May Be a Risk Factor for Growth Disturbance Following All-inside All-Epiphyseal Anterior Cruciate Ligament Reconstruction

Primary intraosseous papillary intralymphatic angioendothelioma of the distal femoral epiphysis: a case report with literature review.

Papillary intralymphatic angioendothelioma (PILA) is an exceptionally rare metastasizing soft tissue tumor. It tends to arise in the subcutaneous tissues of distal extremities in children. Only four intraosseous PILA cases have been reported until now in English language literature. We present a case of PILA arising in the distal femoral epiphysis of a 50-year-old female patient. It started as a relentless pain in her left knee. A plain radiography revealed a radiolucent area in the left internal femoral condyle. Computerized tomography revealed a 1-cm lytic lesion with a sclerotic rim. Magnetic resonance images showed a significant bone marrow edema signal focused on a 1-cm subchondral lesion suggestive of an intraarticular osteoid osteoma. Histologically, the tumor contained vascular channels covered by a single endothelial layer with intraluminal papillary endothelial structures lined with hobnail cells. Immunohistochemically, the cells were positive for ERG, CD31, and D2-40. The tumor underwent cryoablation and 6months later, after local recurrence or tumor persistence, a wide tumor resection was referred. After 7years of follow-up, the patient displayed neither local recurrence nor distant metastases. Primary intraosseous PILAs are exceedingly rare tumors that should be considered in the differential diagnosis of vascular bone tumors.

Trabecular architecture of the distal femur in extant hominids.

Extant great apes are characterized by a wide range of locomotor, postural and manipulative behaviours that each require the limbs to be used in different ways. In addition to external bone morphology, comparative investigation of trabecular bone, which (re-)models to reflect loads incurred during life, can provide novel insights into bone functional adaptation. Here, we use canonical holistic morphometric analysis (cHMA) to analyse the trabecular morphology in the distal femoral epiphysis of Homo sapiens (n = 26), Gorilla gorilla (n = 14), Pan troglodytes (n = 15) and Pongo sp. (n = 9). We test two predictions: (1) that differing locomotor behaviours will be reflected in differing trabecular architecture of the distal femur across Homo, Pan, Gorilla and Pongo; (2) that trabecular architecture will significantly differ between male and female Gorilla due to their different levels of arboreality but not between male and female Pan or Homo based on previous studies of locomotor behaviours. Results indicate that trabecular architecture differs among extant great apes based on their locomotor repertoires. The relative bone volume and degree of anisotropy patterns found reflect habitual use of extended knee postures during bipedalism in Homo, and habitual use of flexed knee posture during terrestrial and arboreal locomotion in Pan and Gorilla. Trabecular architecture in Pongo is consistent with a highly mobile knee joint that may vary in posture from extension to full flexion. Within Gorilla, trabecular architecture suggests a different loading of knee in extension/flexion between females and males, but no sex differences were found in Pan or Homo, supporting our predictions. Inter- and intra-specific variation in trabecular architecture of distal femur provides a comparative context to interpret knee postures and, in turn, locomotor behaviours in fossil hominins.

Does the intercondylar approach provide a better outcome for chondroblastoma of the distal femur in skeletally immature patients?

The epiphyseal approach to a chondroblastoma of the intercondylar notch of a child's distal femur does not provide adequate exposure, thereby necessitating the removal of a substantial amount of unaffected bone to expose the lesion. In this study, we compared the functional outcomes, local recurrence, and surgical complications of treating a chondroblastoma of the distal femoral epiphysis by either an intercondylar or an epiphyseal approach. A total of 30 children with a chondroblastoma of the distal femur who had been treated by intraregional curettage and bone grafting were retrospectively reviewed. An intercondylar approach was used in 16 patients (group A) and an epiphyseal approach in 14 (group B). Limb function was assessed using the Musculoskeletal Tumor Society (MSTS) scoring system and Sailhan's functional criteria. At final follow-up, the mean MSTS score was 29.1 (SD 0.9) in group A and 26.7 (SD 1.5) in group B (p = 0.006). According to Sailhan's criteria, the knee function was good and fair in 14 (87.5%) and two (12.5%) patients of group A, and eight (57.1%) and six (42.9%) patients of group B, respectively (p = 0.062). The lesion had recurred in one patient (6.2%) in group A and four patients (28.6%) in group B. Limb shortening > 1 cm was recorded in one patient (6.2%) from group A and six patients (42.8%) from group B. Joint degeneration was noted in one patient from group A and three patients from group B. An intercondylar approach to a chondroblastoma of the middle two-quarters of the distal femoral epiphysis results in better outcomes than a medial or lateral epiphyseal approach: specifically, better limb function, a lower rate of recurrence, and a lower rate of physeal damage and joint degeneration.

Development and Validation of Flaxseed Lignan-Enriched Set-Type Fermented Milk to Manage Postmenopausal Osteoporosis

A functional set dahi (fermented milk analogous to yoghurt) with a desirable probiotic (Lactiplantibacillus plantarum A5) count of 9.36 log CFU/mL and excellent techno-functional attributes (DPPH: 41.95% RSA, firmness: 485.49 g, sensory overall acceptability: 8.51) was developed to contain 260 mg of SDG in 20 g of dahi. Twenty-four female Albino Wistar rats (3 months old, &gt;180 g) were ovariectomized (OVX) and divided into three groups: OVX control, OVX and control dahi, and OVX and SDG-enriched dahi. The animal study found that ovariectomy decreased serum calcium, oestrogen, and bone ash calcium levels by 32.27, 30.95, and 48.46 percent, respectively, compared to the sham group (n = 8), while daily administration of SDG-enriched dahi (20 g) for eight weeks restored them. The proximal tibial metaphysis and distal femoral epiphysis micro-CT study showed that the ovariectomy lowered bone mineral density (BMD) by 11.06% and 9.18%, respectively, and lowered Trabecular thickness (Tb. Th) by 12.66% and 11.86%, respectively, while increasing Trabecular separation (Tb. Sp.) by 90.69% and 87.70%, respectively, compared to the sham control-group rats. SDG-enriched dahi improved BMD by 16.06 and 12.24% and Tb. Th by 35.32 and 19.62%, respectively, and decreased Tb. Sp by 47.04 and 47.22%, respectively, in OVX rats. The results suggest that the developed set dahi may help treat postmenopausal osteoporosis.

Forensic age estimation of the knee by post-mortem DR, CT, and MR imaging: a comparative study

It is believed by many that reference data for age estimation purposes must be imaging-modality specific. A study from our department has however proven otherwise. We therefore found it interesting to investigate this further by looking at the level of agreement between different imaging modalities. The aim of this study was to investigate the level of agreement between the three radiological modalities, computed tomography (CT), magnetic resonance imaging (MRI), and digital radiography (DR), in assessing the ossification of the epiphyses of the knee. A total of 34 deceased individuals of 10–25 years of age, brought in for a medicolegal autopsy at our department, were scanned by CT, MRI, and DR. The ossification stages of the three bones of the right knee, distal femoral, proximal tibial, and proximal fibular epiphysis were assessed using the established combined staging method by Schmeling et al. and Kellinghaus et al. Analysis of the results by Cohen’s weighted kappa showed a good agreement between CT and DR (K = 0.61–0.70), and MRI and DR (K = 0.68–0.79) but only moderate agreement between CT and MRI (K = 0.55–0.57). This leads us to conclude that different radiological images cannot be used interchangeably for age estimation purposes, so reference material needs to be imaging-modality specific. However, to make a more general conclusion research on a larger population is needed.

Obesity impairs revascularization and bone healing in a mouse model of osteonecrosis.

Osteonecrosis of the femoral head (ONFH) is a devastating bone disease that is caused by a disruption of blood supply leading to necrotic cell death. Clinically, it was found that obesity has a high prevalence with ONFH. However, it remains unclear how obesity may directly affect tissue regeneration and bone healing in osteonecrosis (ON). The purpose of this study is to investigate the effects of obesity and weight loss (WL) on ON healing. In this study, we induced obesity and WL in an established surgery-induced ON mouse model via feeding a high-fat diet (HFD) and altering the diet respectively. All mice received a surgical induction of ON of distal femoral epiphysis at the age of 12 weeks. HFD was switched to normal diet (ND) after ON surgery to induce WL. Mouse body weight was recorded weekly. Mouse body composition was scanned by DEXA (Dual-energy X-ray absorptiometry) right after sacrifice at the age of 16 weeks. The distal femoral bone samples were fixed and embedded for histology such as H&E, immunohistochemistry, and TRAP staining. In this study, we found that HFD-induced obesity impaired revascularization and bone remodeling showing decreased vessel areas and reduced osteoblast and osteoclast numbers. WL could rescue obesity-induced bone healing defects. Our study is the first to test the direct effects of obesity and WL on ON bone healing. We believe our work may provide new concepts for osteonecrosis treatment in obese patients.

Indian patients with CHST3-related chondrodysplasia with congenital joint dislocations.

CHST3-related chondrodysplasia with congenital joint dislocations (CDCJD, #MIM 143095), is a rare genetic skeletal disorder caused by biallelic loss of function variants in CHST3. CHST3 is critical for the sulfation of chondroitin sulfate. This study delineates the clinical presentation of nine individuals featuring the key symptoms of CDCJD; congenital joint (knee and elbow) dislocations, short trunk short stature progressive vertebral anomalies, and metacarpal shortening. Additional manifestations include irregular distal femoral epiphysis, supernumerary carpal ossification centers, bifid humerus, club foot, and cardiac abnormalities. Sanger sequencing was carried out to investigate molecular etiology in eight patients and exome sequencing in one. Genetic testing revealed five homozygous variants in CHST3 (four were novel and one was previously reported). All these variants are located on sulfotransferase domain of CHST3 protein and were classified as pathogenic/ likely pathogenic. We thus report on nine individuals with CHST3-related chondrodysplasia with congenital joint dislocations from India and suggest monitoring the health of cardiac valves in this condition.

Postmortem computed tomography assessment of skeletal and dental age in Polish children, adolescents, and young adults

This paper presents a retrospective analysis of postmortem computed tomography (PMCT) scans of secondary ossification centers in the medial clavicular epiphysis, iliac crest apophysis, proximal humeral epiphysis, distal femoral epiphysis, proximal tibial epiphysis, and distal tibial epiphysis. At the same time, we analyzed PMCT scans of the maxillary and mandibular incisors, canines, premolars, and molars. We assessed 203 corpses, whose age ranged from 2 to 30 years, including 156 males and 47 females. The purpose of our study was to compare the processes of secondary ossification center fusion and permanent tooth maturation. Our research hypothesis was that certain stages of skeletal and dental maturation occur along consistent timelines that can be related to the chronological age. Secondary ossification center fusion was evaluated based on Kreitner and also McKern and Steward’s classifications. The process of permanent tooth maturation was evaluated with Demirjian’s method. Spearman’s correlation coefficients (Rho) were positive in all analyses, which indicates that epiphyseal fusion progresses with age. The strongest relationship between the age and the stages of ossification was observed in the proximal tibial epiphysis (p < 0.001; Rho = 0.93) in females and in the medial clavicular epiphysis (p < 0.001; Rho = 0.77) in males. Studies show the importance of concomitant analysis of skeletal and dental maturation with a subsequent comparison of the results to achieve a greater precision in age estimation. A comparison of the results obtained in the study population of Polish children, adolescents, and young adults with the results of other studies in populations of similar ages showed a number of similarities in the time windows of dental and skeletal maturation. These similarities may help in age estimation.

Temporal transcriptome features identify early skeletal commitment during human epiphysis development at single-cell resolution

Human epiphyseal development has been mainly investigated through radiological and histological approaches, uncovering few details of cellular temporal genetic alternations. Using single-cell RNA sequencing, we investigated the dynamic transcriptome changes during post-conception weeks (PCWs) 15-25 of human distal femoral epiphysis cells. We find epiphyseal cells contain multiple subtypes distinguished by specific markers, gene signatures, Gene Ontology (GO) enrichment analysis, and gene set variation analysis (GSVA). We identify the populations committed to cartilage or ossification at this time, although the secondary ossification centers (SOCs) have not formed. We describe the temporal alternation in transcriptional expression utilizing trajectories, transcriptional regulatory networks, and intercellular communication analyses. Moreover, we find the emergence of the ossification-committed population is correlated with the COL2A1-(ITGA2/11+ITGB1) signaling. NOTCH signaling may contribute to the formation of cartilage canals and ossification via NOTCH signaling. Our findings will advance the understanding of single-cell genetic changes underlying fetal epiphysis development.

The distal femoral epiphysis used as a fetal maturity marker: Implications of extant medical data for bioarcheological analysis

AbstractThe distal epiphysis of the femur is classically reported as a marker of fetal maturity and is thus identified in a bioarcheological context as an indicator that an individual died at or around the time of birth; it thus provides crucial information in the creation of the biological profile and associated burial practices. The aim of the present study was to re‐evaluate this use by investigating an extant sample to assess (i) the age‐related frequencies of both distal femoral and proximal tibial epiphyses and (ii) the influence of factors such as sex, vitality, and morbidity on the maturation of both epiphyses. The study was conducted on medical CT scans acquired in utero and ex utero between 2008 and 2017 in the hospital of Marseille (France). The final sample included 248 individuals aged between 26 and 42 completed gestational weeks (GW). Based on the results obtained in this study, 11% of the individuals from the sample aged between 26 and 33 completed GW had already developed a distal femoral epiphysis, whereas individuals aged between 38 and 42 GW had already developed both femoral and tibial epiphyses. According to these observations and current obstetrical practice, this maturation indicator cannot therefore be considered a precise estimator of whether a fetus is at term or not in an archeological context. Similarly, no delayed ossification was found among individuals who did not survive to 42 GW, or among those with severe developmental abnormalities, which does not support the hypothesis that delayed epiphysis maturation of the distal femur may be a morbidity marker for this age group in past populations.

Correcting for distal femoral asymmetry is necessary to determine postoperative alignment deviations from planned alignment of the femoral component

BackgroundOne method for assessing the accuracy of manual, patient-specific, navigational, and robotic-assisted total knee arthroplasty (TKA) instrumentation is to use a post-operative computer tomogram and determine the deviation of the femoral component alignment relative to the planned alignment in the native (i.e. healthy) contralateral distal femoral epiphysis. However, side-to-side asymmetry might introduce errors which inflate alignment deviations. This study quantified asymmetry in the distal femoral epiphysis. MethodsHigh resolution CT images (0.5 mm slice thickness) were acquired from bilateral lower limb specimens of 13 skeletally mature subjects with no skeletal abnormalities. Images were segmented to generate 3D femur models. Asymmetry was quantified by differences in positions and orientations required to shape-match the distal epiphysis of the mirror 3D femur model to the distal epiphysis of the contralateral 3D femur model. ResultsAsymmetry was due to random rather than systematic differences. Random differences (i.e. standard deviations) in proximal–distal (P-D) and anterior-posterior (A-P) positions were 1.1 mm and in varus-valgus (V-V) and internal-external (I-E) orientations were 0.9° and 1.3°, respectively. These represented substantial relative errors of up to 50 % in previously reported overall alignment deviations. ConclusionsAlthough small in an absolute sense, asymmetry of the distal femur epiphysis introduced substantial relative errors when assessing accuracy of femoral component alignment in TKA. When post-operative computer tomograms are used to assess the accuracy of manual, patient specific, navigational, and robotic-assisted TKA instrumentation, the overall deviation should be corrected for asymmetry to better indicate the accuracy of the surgical technique.

The Utilization of Osteoarticular Transfer System in the Treatment of Distal Femur Osteoid Osteoma: A Case Report

Introduction: Tumor excision of the subchondral bone of the distal femur epiphysis is technically challenging particularly in skeletally immature patients due to the open physis above and articular surface below. Preservation of the physis, maintenance of structural support to, and integrity of, the cartilage, and conservation of joint kinematics must all be considered and are often threatened by current percutaneous or open surgical treatment options. Materials and Methods: We present a case of a 16-year-old male athlete with a distal femur epiphyseal bone lesion. He underwent transarticular en bloc excision and autograft reconstruction using osteoarticular transfer system (OATS) technique. Results: Final pathology revealed complete excision of an osteoid osteoma. The patient had regained full strength and range of motion at 3 months postoperatively, and at 22 months postoperatively was free of disease and back to full level of athletic participation. Conclusions: This article describes a technique for excision of subchondral epiphyseal bone lesions in the distal femur in skeletally immature patients which mitigates the risk of complications associated with physeal injury, incomplete tumor resection, and iatrogenic injury to the overlying cartilage.

EPIPHYSIS INJURY AROUND KNEE (FLEXION TYPE, SALTER-HARRIS TYPE 1)

Introduction: Fractures of the proximal tibial and distal femur epiphysis rare. It has been estimated that fractures of the upper tibial and distal femur epiphysis account for 0.5-3.1% of all epiphyseal injuries. Who had no neurovascular decit, with xed extension deformity at the left knee was treated early with closed reduction techniques. We present a case of a adolscent child who develops injury while playing. The patient p Case Series: resented in emergency room with extremely swollen knee and soft tissue swelling (hemarthrosis), he was unable to lift his leg actively due to severe pain because of hamstrings spasm, and he had no wound over his left knee and had no other associated injuries. Plain radiographs were taken which revealed, separated proximal tibial and distal femur epiphysis (salter harris Type 1 injury) The epiphysis was anteriorly displaced fracture line extending beyond growth plate through metaphysis and tibial tuberosity also displaced anteriorly, no patellar fracture, radiograph also revealed no intra-articular fracture as joint appears congruent. Under spinal anesthesia, under all aseptic precautions traction was applied for few minutes, the fracture was reduced closed as the hamstring spasm gave way, reduction was conrmed under image intensier in both AP and lateral planes, and joint congruity was examined. Post-operative patient was immobilized with nil weight bearing for 4 weeks, check X-rays taken, he was mobilized in wheelchair. After 4 weeks slab was removed, K-wires were removed, and partial weight bearing was started with rehabilitation for full range of motion of the left knee. At 6 weeks, both the knee joints appeared symmetrical with no abnormalities or limb length discrepancy or instability with knee from 0° to 140°, with full weight bearing. Although Conclusion: less commonly seen, Salter-Harris Type 1 injuries to proximal tibial and dista femur physis, if managed early with closed reduction and xation, excellent long-term results can be achieved

Cold stress during room temperature housing alters skeletal response to simulated microgravity (hindlimb unloading) in growing female C57BL6 mice

Laboratory mice are typically housed at temperatures below the thermoneutral zone for the species, resulting in cold stress and premature cancellous bone loss. Furthermore, mice are more dependent upon non-shivering thermogenesis to maintain body temperature during spaceflight, suggesting that microgravity-induced bone loss may be due, in part, to altered thermogenesis. Consequently, we assessed whether housing mice at room temperature modifies the skeletal response to simulated microgravity. This possibility was tested using the hindlimb unloading (HLU) model to mechanically unload femora. Humeri were also assessed as they remain weight bearing during HLU. Six-week-old female C57BL6 (B6) mice were housed at room temperature (22 °C) or near thermoneutral (32 °C) and HLU for 2 weeks. Compared to baseline, HLU resulted in cortical bone loss in femur, but the magnitude of reduction was greater in mice housed at 22 °C. Cancellous osteopenia in distal femur (metaphysis and epiphysis) was noted in HLU mice housed at both temperatures. However, bone loss occurred at 22 °C, whereas the bone deficit at 32 °C was due to failure to accrue bone. HLU resulted in cortical and cancellous bone deficits (compared to baseline) in humeri of mice housed at 22 °C. In contrast, fewer osteopenic changes were detected in mice housed at 32 °C. These findings support the hypothesis that environmental temperature alters the skeletal response to HLU in growing female mice in a bone compartment-specific manner. Taken together, species differences in thermoregulation should be taken into consideration when interpreting the skeletal response to simulated microgravity.

The distal femoral epiphysis in forensic age diagnostics: studies on the evaluation of the ossification process by means of T1- and PD/T2-weighted magnetic resonance imaging

The age of majority, which corresponds to the age of 18 years in most European countries, plays a crucial role for a large number of legal decisions. Accordingly, an increasing number of requests by authorities to forensic age estimation experts comprise the question of whether the age of 18 years has been reached by an individual. In recent years, novel study data suggested that magnetic resonance imaging (MRI) of the knee might likewise allow for the determination of majority beyond reasonable doubt. However, the data basis, especially concerning the distal femoral epiphysis (DFE), is still poor. For this reason, 392 routine MRI cases of the knee (204 males and 188 females of a Western Caucasian population, aged between 12 and 25 years) were retrospectively analyzed. T1-weighted and water-selective fat-saturated PD/T2-weighted sequences, generated at 1.5 and 3.0 T clinical MR scanners, were available. Ossification stages of the DFE were determined by means of the classification system by Vieth et al. (Eur Radiol 2018; 28:3255–3262). Both the intra-observer agreement and inter-observer agreement were found to be “very good” (κ = 0.899 and κ = 0.830). The present study confirmed that MRI of the DFE is suitable to determine majority in both sexes when stage 6 is present as the study revealed minimum ages above the age of 18 years for this stage (20.40 years in males and 20.60 years in females). Accordingly, the data represent a strong support for the so far existing database. Hence, the investigation of the knee using routine MRI appears to become a realistic alternative for forensic age estimation practice in the near future.

Circular External Fixation for Distal Femoral Physeal Injury: A Case Report

Background: Distal femoral physeal injuries are a challenging clinical scenario because the injuries have a high risk of growth disturbance. The selected treatments include closed reduction and cast immobilization, percutaneous pin fixation, and cannulated screws or internal fixation, but these treatments have some complications. Circular external fixation enables rigid immobilization and walking with full weight bearing. To the best of our knowledge, there is no article on the results of using circular external fixation for distal femoral physeal injury. This case is the first in which circular external fixation for distal femoral physeal injury is used. Case Presentation: A 9-year-old boy was injured in a skiing accident, and his injury was a Salter-Harris type II fracture of the distal femoral epiphysis. We immediately performed percutaneous pin fixation with circular external fixation under general anesthesia. After surgery, he was allowed to walk with full weight bearing. One year after surgery, he had no pain, and his knee regained full extension and 140°flexion. Conclusion: We consider circular external fixation to be an effective treatment option because of its rigid immobilization without injury to the plate. However, we and patients must fully acknowledge its difficulties (i.e., pin-site problems, neurologic injury, vascular injury, joint stiffness, and pain, and difficulty sleeping).

Comparative Osteogenesis and Degradation Behavior of Magnesium Implant in Epiphysis and Diaphysis of the Long Bone in the Rat Model.

Magnesium (Mg), as a biodegradable material, is a promising candidate for orthopedic surgery. Long-bone fractures usually occur in cancellous-bone-rich epiphysis at each end or the cortical-rich diaphysis in the center, with different bone healing processes. Little is known about the differences in results between the two regions when applying Mg implants. Therefore, this study aimed to compare the biodegradation and osteogenesis of Mg implants in a rat model’s epiphysis and diaphysis of the long bone. Twelve male Sprague Dawley rats underwent Mg rod implantation in the distal femoral epiphyses and tibial diaphyses. Every three weeks for up to twelve weeks, degradation behavior, gas evolution, and new bone formation were measured by micro CT. Histomorphology was analyzed by Hematoxylin and Eosin, Villanueva bone staining, and TRAP staining for osteoclastogenesis evaluations. Micro-CT analysis showed statistically significant higher new bone formation in the epiphysis group than in the diaphysis group, which correlated with a lower gas volume. Histological analysis showed higher osseointegration of Mg implants in the epiphyseal region than in the diaphyseal region. The magnesium implant’s osteoclastogenesis-inhibiting properties were shown in the surrounding areas in both the cortical bone of the diaphysis and the cancellous bone of the epiphysis. Our findings show the differences in the magnesium implant’s osteogenesis and biodegradation in the epiphysis and the diaphysis. These dissimilarities indicate a better response of the epiphyseal region to the Mg implants, a promising biomaterial for orthopedic surgery applications.

Paper 20: The Relationship of Schottle’s Point to the Medial Distal Femoral Physis: A Digitally Reconstructed Radiograph and 3-Dimensional Computed Tomography Study

Objectives:There is significant controversy regarding ideal medial patellofemoral ligament reconstruction (MPFLR) femoral tunnel position in the pediatric setting. The authors identified 3 main gaps in knowledge. First, the position of the radiographic MPFLR start point (Schottle’s point) relative to the medial distal femoral epiphysis is not well defined. Second, although anatomic studies have suggested tunnel trajectories that avoid physeal contact, these trajectories are not based upon the widely used Schottle’s point, providing limited intraoperative utility. Third, prior studies provide conflicting data regarding position of the MPFL origin relative to the distal femoral physis, particularly in younger patients. The purpose of this study was to determine the proximity of Schottle’s point to the medial distal femoral physis and the medial epicondyle using a digitally reconstructed radiographs (DRR) and three-dimensional computed tomography (CT) models.Methods:The institutional picture archiving and communication system (PACS) was queried for CT imaging studies of pediatric knees with open physes. CT data were imported to a Python based, open-source image processing software and were transformed to create true lateral digitally reconstructed radiographs (DRR) (Figure 1) and 3-dimensional (3D) renderings of the distal femur (Figure 2). Schottle’s point and the medial epicondyle were registered using fiducial markers and 3D distance measurements were then obtained from Schottle’s point on the medial cortex to 1) the medial epicondyle, 2) the physeal point directly superior to Schottle’s point, and 3) the shortest distance to the medial physis on the cortical surface. A 6-millimeter circle was used to simulate reaming diameter and physeal intersections were tabulated.Results:49 pediatric knee CT scans with open physes were included in the data. Average patient age was 13.0 ± 2.3 years (range: 6-17 years). Mean minimum distance from the medial physis to Schottle’s point was 9.9 mm ± 3.0mm (range: 3.4-16.1 mm) (Figure 3). In 49 of 49 cases (100%), Schottle’s point was distal to the physis. Schottle’s point was localized at a mean distance of 7.5mm ± 3.14mm posterior to the medial epicondyle and 6.1mm ± 2.9mm superior to the medial epicondyle. Using a 6mm reaming diameter, 3 (6%) femurs in our study would have violation of the medial distal femoral physis. Moving the start point 3mm distally would result in 0 of 49 (0%) having physeal injury.Conclusions:Historically, characterizing the position of the origin of the MPFL on the medial condyle relative to the medial distal femoral physis has been challenging. Prior cadaveric studies have suggested the MPFL originates proximal to the physis in younger patients (<7 years). However, more recent cadaveric studies have challenged this idea, finding the bony landmarks of the MPFL origin to be distal to the physis. Although these studies have sparked significant discussion regarding the pediatric MPFL origin, they have small numbers of specimens. Using a more surgically relevant approach, the present study demonstrates that Schottle’s point is consistently distal to the distal femoral physis.Prior studies have suggested anterior and distal drill trajectories that may minimize physeal injury. Although useful, these studies do not assess drilling path relative to the commonly used radiographically identified starting point, Schottle’s point. The present study complements this prior work by addressing the radiographic start point upon which the drill trajectory is based intraoperatively. Based on the present study, the use of Schottle’s point without distalization would lead to physeal injury in 6% of cases.Further, prior cadaveric anatomic studies are subject to limitations of the availability and expense of pediatric specimens and are therefore limited to small sample sizes. The methodology of the present study, by using readily available fine cut CT data, is not subject to such constraints. The present investigation offers a larger sample size than any previously published pediatric MPFL anatomic study and uses a highly accurate and repeatable methodology. This unique methodology may be more broadly applicable to the study of pediatric procedures near the physis.The radiographically defined surgical start point for MPFL femoral tunnel placement (Schottle’s point), is consistently distal to the medial distal femoral physis. Mean minimum distance from Schottle’s point to the physis on the medial cortex is 9.9mm. Using Schottle’s point for the start of tunnel drilling leads to physis violation in 6% of cases, when using a 6mm reamer. Distalization of the start point by 3mm leads to avoidance of physeal injury in all cases.Figure 1.Digitally Reconstructed Radiograph with Identification of Schottle’s PointFigure 2.3D Rendering with Physeal Distance MeasurementFigure 3.Saggital Plane Plot of Schottle’s Point and Closest Point on Medial Physis