Relationship Between Age and Pathology With Treatment of Pediatric and Adolescent Discoid Lateral Meniscus: A Report From the SCORE Multicenter Database

BACKGROUND

Surgical treatment options of discoid lateral meniscus in pediatric patients consist of saucerization with or without meniscal repair, meniscocapular stabilization, and, less often, subtotal meniscectomy.

PURPOSE

To describe a large, prospectively collected multicenter cohort of discoid menisci undergoing surgical intervention, and further investigate corresponding treatment of discoid menisci.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A multicenter quality improvement registry (16 institutions, 26 surgeons), Sports Cohort Outcomes Registry, was queried. Patient characteristics, discoid type, presence and type of intrasubstance meniscal tear, peripheral rim instability, repair technique, and partial meniscectomy/debridement beyond saucerization were reviewed. Discoid meniscus characteristics were compared between age groups (<14 and >14 years old), based on receiver operating characteristic curve, and discoid morphology (complete and incomplete).

RESULTS

In total, 274 patients were identified (mean age, 12.4 years; range, 3-18 years), of whom 55.6% had complete discoid. Meniscal repairs were performed in 55.1% of patients. Overall, 48.5% of patients had rim instability and 36.8% had >1 location of peripheral rim instability. Of the patients, 21.5% underwent meniscal debridement beyond saucerization, with 8.4% undergoing a subtotal meniscectomy. Patients <14 years of age were more likely to have a complete discoid meniscus (P < .001), peripheral rim instability (P = .005), and longitudinal tears (P = .015) and require a meniscal repair (P < .001). Patients ≥14 years of age were more likely to have a radial/oblique tear (P = .015) and require additional debridement beyond the physiologic rim (P = .003). Overall, 70% of patients <14 years of age were found to have a complete discoid meniscus necessitating saucerization, and >50% in this young age group required peripheral stabilization/repair.

CONCLUSION

To preserve physiological "normal" meniscus, a repair may be indicated in >50% of patients <14 years of age but occurred in <50% of those >14 years. Additional resection beyond the physiological rim may be needed in 15% of younger patients and 30% of those aged >14 years.

A Corresponding Point Measurement System Provides Reliable Measurement of Displacement for Medial Epicondyle Fractures

Little consensus exists on the best method for evaluation and management of pediatric medial epicondyle fractures because of an inability to reliably evaluate fracture displacement with standard imaging techniques. This study aimed to determine the performance of various radiographic views in evaluating displaced medial epicondyle fractures when using a standardized measurement methodology.

METHODS

Ten fellowship-trained pediatric orthopaedic surgeons assessed fracture displacement in 6 patients with displaced medial epicondyle fractures using radiographic views (anteroposterior, lateral, axial, internal oblique [IO], and external oblique [EO]) and computed tomographic (CT) views (axial, 3-dimensional [3D] horizontal, and 3D vertical). Raters used a corresponding point method for measuring displacement. For each image, raters measured the absolute displacement, categorized the percent of displacement relative to the size of the fragment and fracture bed, and indicated a treatment option. Interobserver reliability was calculated for each view. Bland-Altman plots were constructed to evaluate the bias between each radiograph and the mean of the CT methods.

RESULTS

For absolute displacement, anteroposterior and EO views showed almost perfect interobserver reliability, with an interclass correlation coefficient (ICC) of 0.944 for the anteroposterior view and an ICC of 0.975 for the EO view. The axial view showed substantial reliability (ICC = 0.775). For the displacement category, almost perfect reliability was shown for the anteroposterior view (ICC = 0.821), the axial view (ICC = 0.911), the EO view (ICC = 0.869), and the IO view (ICC = 0.871). Displacement measurements from the anteroposterior, axial, and EO views corresponded to the measurements from the CT views with a mean bias of <1 mm for each view. However, the upper and lower limits of agreement were >5 mm for all views, indicating a substantial discrepancy between radiographic and CT assessments. Treatment recommendations based on CT changed relative to the recommendation made using the anteroposterior view 29% of the time, the EO view 41% of the time, and the axial view 47% of the time.

CONCLUSIONS

Using a corresponding point measurement system, surgeons can reliably measure and categorize fracture displacement using anteroposterior, EO, and axial radiographic views. CT-based measurements are also reliable. However, although the mean difference between the radiograph-based measurements and the CT-based measurements was only about 1 mm, the discrepancy between radiographic views and CT-based methods could be as large as 5 to 6 mm.

LEVEL OF EVIDENCE

Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Genomic answers for children: Dynamic analyses of >1000 pediatric rare disease genomes

PURPOSE

This study aimed to provide comprehensive diagnostic and candidate analyses in a pediatric rare disease cohort through the Genomic Answers for Kids program.

METHODS

Extensive analyses of 960 families with suspected genetic disorders included short-read exome sequencing and short-read genome sequencing (srGS); PacBio HiFi long-read genome sequencing (HiFi-GS); variant calling for single nucleotide variants (SNV), structural variant (SV), and repeat variants; and machine-learning variant prioritization. Structured phenotypes, prioritized variants, and pedigrees were stored in PhenoTips database, with data sharing through controlled access the database of Genotypes and Phenotypes.

RESULTS

Diagnostic rates ranged from 11% in patients with prior negative genetic testing to 34.5% in naive patients. Incorporating SVs from genome sequencing added up to 13% of new diagnoses in previously unsolved cases. HiFi-GS yielded increased discovery rate with >4-fold more rare coding SVs compared with srGS. Variants and genes of unknown significance remain the most common finding (58% of nondiagnostic cases).

CONCLUSION

Computational prioritization is efficient for diagnostic SNVs. Thorough identification of non-SNVs remains challenging and is partly mitigated using HiFi-GS sequencing. Importantly, community research is supported by sharing real-time data to accelerate gene validation and by providing HiFi variant (SNV/SV) resources from >1000 human alleles to facilitate implementation of new sequencing platforms for rare disease diagnoses.

Elevated glucose acts directly on osteocytes to increase sclerostin expression in diabetes

Bone quality in diabetic patients is compromised, leading to weaker bones and increased fracture risk. However, the mechanism by which this occurs in diabetic bone remains to be fully elucidated. We hypothesized that elevated glucose and glucose variation would affect the function of osteocytes, essential regulators of bone homeostasis and quality. To first test this hypothesis, we used the IDG-SW3 osteocyte-like cell line to examine the effects of glucose levels on osteocyte function and viability in vitro. We confirmed our in vitro findings using the in vivo streptozotocin-induced (STZ) diabetic rat model and ex-vivo cultured osteocytes from these rats. IDG-SW3 cells cultured under high glucose conditions displayed significantly increased Sost mRNA(100-fold) and sclerostin protein, a negative regulator of bone formation(5000-fold), compared to cells in control media. mRNA expression of osteoblast markers such as Osx, Ocn and Col1a1 was unaffected by glucose. Factors associated with osteoclast activation were affected by glucose, with Rankl being upregulated by low glucose. Opg was also transiently upregulated by high glucose in mature IDG-SW3 cells. Induction of diabetes in Sprague-Dawley rats via a single dose of STZ (70 mg/kg) resulted in elevated maximum glucose and increased variability compared to control animals (670/796 vs. 102/142 mg/dL). This was accompanied by increased Sost/sclerostin expression in the osteocytes of these animals. These results show that glucose levels directly regulate osteocyte function through sclerostin expression and suggest a potential mechanism for the negative impact of diabetes on bone quality.

In vivo evaluation of stem cell aggregates on osteochondral regeneration

To date, many osteochondral regenerative approaches have utilized varied combinations of biocompatible materials and cells to engineer cartilage. Even in cell-based approaches, to date, no study has utilized stem cell aggregates alone for regenerating articular cartilage. Thus, the purpose of this study was to evaluate the performance of a novel stem cell-based aggregate approach in a fibrin carrier to regenerate osteochondral defects in the Sprague-Dawley rat trochlear groove model. Two different densities of rat bone marrow mesenchymal stem cell (rBMSC) aggregates were fabricated by the hanging drop technique. At 8 weeks, the cell aggregates supported the defects and served as a catalyst for neo-cartilage synthesis, and the experimental groups may have been beneficial for bone and cartilage regeneration compared to the fibrin-only control and sham groups, as evidenced by histological assessment. The cell density of rBMSC aggregates may thus directly impact chondrogenesis. The usage of cell aggregates with fibrin as a cell-based technology is a promising and translational new treatment strategy for repair of cartilage defects. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1606-1616, 2017.

Microsphere-Based Osteochondral Scaffolds Carrying Opposing Gradients Of Decellularized Cartilage And Demineralized Bone Matrix

Extracellular matrix (ECM) "raw materials" such as demineralized bone matrix (DBM) and cartilage matrix have emerged as leading scaffolding materials for osteochondral regeneration owing to their capacity to facilitate progenitor/resident cell recruitment, infiltration, and differentiation without adding growth factors. Scaffolds comprising synthetic polymers are sturdy yet generally lack cues for guiding cell differentiation. We hypothesized that opposing gradients of decellularized cartilage (DCC) and DBM in polymeric microsphere-based scaffolds would provide superior regeneration compared to polymer-only scaffolds in vivo. Poly(D,L-lactic-co-glycolic acid) (PLGA) microsphere-based scaffolds were fabricated, either with opposing gradients of DCC and DBM encapsulated (GRADIENT) or without DCC and DBM (BLANK control), and implanted into rabbit osteochondral defects in medial femoral condyles. After 12 weeks, gross morphological evaluation showed that the repair tissue in about 30% of the implants was either slightly or significantly depressed, hinting toward rapid polymer degradation in scaffolds from both of the groups. Additionally, no differences were observed in gross morphology of the repair tissue between the BLANK and GRADIENT groups. Mechanical testing revealed no significant differences in model parameter values between the two groups. Histological observations demonstrated that the repair tissue in both of the groups was fibrous in nature with the cells demonstrating notable proliferation and matrix deposition activity. No adverse inflammatory response was observed in any of the implants from the two groups. Overall, the results emphasize the need to improve the technology in terms of altering the DBM and DCC concentrations, and tailoring the polymer degradation to these concentrations.

Combined posterolateral corner and acute anterior cruciate ligament injuries in an adolescent cohort: a magnetic resonance imaging analysis

PURPOSE

Failure of a reconstructed anterior cruciate ligament (ACL) has significant morbidity in the paediatric and adolescent patient population. Untreated concomitant posterolateral corner (PLC) injury is an identified cause of failed ACL reconstruction; however, the injury pattern has yet to be defined for the paediatric population.

METHODS

Magnetic resonance imaging (MRI) studies of the knee performed between 1 January 2009 and 1 January 2013 were retrospectively reviewed. Imaging reports indicating an intra-substance injury of the ACL were reviewed, and all associated injured structures were recorded. Injury patterns were categorised by age, gender, physis status and associated injuries. Logistic regression and chi-square analyses compared ACL disruptions with and without concomitant PLC injuries.

RESULTS

One hundred and twenty-eight patients (74 boys and 54 girls, average age 15.27 years) sustained an ACL disruption. Concomitant injury to the PLC was seen in 13.3% of injuries. Associated PLC injuries were significantly associated with lateral meniscus injury and Segond fractures. Lateral meniscus injury was predictive of PLC injury (p = 0.05) upon logistic regression analysis.

CONCLUSION

Concomitant PLC injuries were found in 13.3% of all ACL disruptions on MRI analysis. Lateral meniscus injuries associated with an ACL disruption were predictive of concomitant PLC injury. Combined injury of the ACL and lateral meniscus should prompt close scrutiny to PLC structures.

Expression of angiogenic factors during distraction osteogenesis

Distraction osteogenesis is a unique and effective way to treat limb length inequality resulting from congenital and posttraumatic skeletal defects. However, despite its widespread clinical use, the cellular and molecular mechanisms by which this surgical treatment promotes new bone formation are not well understood. Previous studies in distraction osteogenesis have noted increased blood flow and vessel formation within the zone of distraction. These observations suggest that distraction osteogenesis may be driven in part by an angiogenic process. Using immunohistological analysis, the expression of two different angiogenic factors (VEGF and bFGF) was shown to localize at the leading edge of the distraction gap, where nascent osteogenesis was occurring. These cells were spatially adjacent to new vessels that were identified by staining for factor VIII. Microarray analysis detected maximal mRNA expression for a wide variety of angiogenic factors including angiopoietin 1 and 2, both Tie receptors, VEGF-A and -D, VEGFR2, and neuropilin 1. Expression of these factors was found to be maximal during the phase of active distraction. Expression of mRNA for extracellular matrix proteins and BMPs was also maximal during this period. A comparison between the patterns of gene expression in fracture healing and distraction osteogenesis revealed similarities; however, the expression of a number of genes showed selective expression in these two types of bone healing. These data suggest that bone formation during distraction osteogenesis is accompanied by the robust induction of factors associated with angiogenesis and support further investigations to elucidate the mechanisms by which angiogenic events promote bone repair and regeneration.

Expression of smooth muscle actin in cells involved in distraction osteogenesis in a rat model

Distraction osteogenesis has proven to be of great value for the treatment of a variety of musculoskeletal problems. Little is still known, however, about the phenotypic changes in the cells participating in the bone formation process, induced by the procedure. Recent findings of the expression of a contractile muscle actin isoform, alpha-smooth muscle actin (SMA), in musculoskeletal connective tissue cells prompted this immunohistochemical study of the expression of SMA in cells participating in distraction osteogenesis in a rat model. The tissues within and adjacent to the distraction site could be distinguished histologically on the basis of cell morphology, density, and extracellular matrix make-up. The percentage of SMA-containing cells within each tissue zone was graded from 0 to 4. The majority of the cells in each of the zones stained positive for SMA within five days of the distraction period. The SMA-containing cells included those with elongated morphology in the center of the distraction site and the active osteoblasts on the surfaces of the newly forming bone. These finding warrant further investigation of the role of this contractile actin isoform in distraction osteogenesis and investigation of the effects of modulation of this actin isoform on the procedure.

Physiologic weight-bearing and consolidation of new bone in a rat model of distraction osteogenesis

To evaluate the effect of weight-bearing on consolidation of the regenerate in distraction osteogenesis, unilateral femoral lengthenings were performed in two groups of rats. In the first group (n = 19) unrestricted weight-bearing was permitted postoperatively, while in the second (n = 18) weight-bearing was prevented via a through-knee amputation. In both groups the distraction protocol involved a 3-day latency period, four daily 0.5-mm lengthenings, and 35 days of consolidation. Healing was evaluated with serial radiographs (days 0, 7, 14, 28, and 35) and at sacrifice with measurement of ash weight, quantitative histology, and mechanical testing. Histomorphometry revealed that the callus in the weight-bearing animals was significantly larger than in the non-weight-bearing animals, primarily due to increases in periosteal and interzone new bone; there was no significant increase in cartilage formation. Weight-bearing had no significant effect on the stiffness, strength, or mineral content of the regenerate. These findings suggest that weight-bearing may be capable of influencing consolidation of the regenerate in distraction osteogenesis. Additional studies will be required to determine the optimal loading for new bone formation.

The role of ketorolac in decreasing length of stay and narcotic complications in the postoperative pediatric orthopaedic patient

The control of postoperative pain in the pediatric orthopaedic patient is a challenging endeavor. Several studies have shown the efficacy of ketorolac tromethamine in the pediatric general surgical population, but its efficacy in the pediatric orthopaedic population remains unproven. Twenty-seven consecutive patients (age 6 months to 18 years) who underwent long-bone osteotomies or foot procedures by a group of three pediatric orthopaedic surgeons were given a ketorolac protocol (1 mg/kg loading, 0.5 mg/kg every 6 h for 24 h). Breakthrough pain was managed with morphine until the patient was able to take oral pain medication, as was any pain after the 24-h period for ketorolac expired. Thirty-seven age- and case-matched patients were used as retrospective controls. The patients in the study who received ketorolac required significantly fewer doses of morphine than did the control group (2.29 +/- 3.98 vs. 10.02 +/- 3.39; p < 0.05). In addition the patients on the ketorolac protocol experienced fewer gastrointestinal side effects (4% vs. 32%; p < 0.05). Finally, the patients in the ketorolac group had a significantly shorter length of stay (3.63 +/- 1.64 days vs. 4.74 +/- 1.76 days; p < 0.05). There were no bleeding complications in either group. Ketorolac is thus a safe and effective means of controlling postoperative pain in the pediatric orthopaedic population while avoiding the troubling maleffects seen with the exclusive use of morphine.