Purpose of review To summarize and discuss the fundamentals of pediatric tibial tubercle avulsion fractures (TTAFs) including preferred imaging modalities, systems for fracture classification, frequently associated injuries, treatment options, outcomes, and common complications. Recent findings Although TTAFs amount to fewer than 1% of all physeal injuries in children, the incidence is increasing, likely because of greater participation in high-level athletics. Summary TTAFs tend to occur in adolescents nearing skeletal maturity who engage in sports with repetitive jumping. The most popular classification system was proposed by Ogden, which defines five fracture types based on the fracture pattern and extent of fragment displacement. Treatment can be nonsurgical or surgical, and indications depend on fracture type. Most fractures are surgical candidates and can be repaired with open reduction and internal fixation (ORIF) or arthroscopy. Arthroscopic approaches can reveal associated soft tissue injuries, such as meniscal tears, and confirm articular reduction. The most common postoperative complication is irritation because of hardware. With proper treatment, both nonsurgical and surgical outcomes are excellent. TTAFs have high rates of union and patients typically return to sports.

Developmental processes are governed by diverse regulatory mechanisms including a suite of signaling pathways employing reversible phosphorylation. With the advent of large-scale phosphoproteomics it is now possible to identify thousands of phosphorylation sites from tissues at distinct developmental stages. We describe here the identification of over 6,000 non-redundant phosphorylation sites from neonatal murine brain. When compared to nearly three times the number of phosphorylation sites identified from three-week-old murine brain, remarkably onethird of the neonatal sites were unique. This fraction only dropped to one-quarter when allowing the site to stray plus or minus 15 residues. This provides evidence for considerable change in the profiles of developmentally-regulated phosphoproteomes. Using quantitative mass spectrometry we characterized a novel phosphorylation site (Ser265) identified uniquely in the neonatal brain on Doublecortin (Dcx), a protein essential for proper mammalian brain development. While the relative levels of Dcx and phospho-Ser265 Dcx between embryonic and neonatal brain were similar, their levels fell precipitously by postnatal day 21, as did phospho-Ser297, a site required for proper neuronal migration. Both sites lie near the microtubule-binding domain and may provide functionally similar regulation via different kinases. The tandem strong cation exchange chromatography (SCX)-immobilized metal affinity chromatography (IMAC) phosphopeptide enrichment schema [9] has been used with high success in multiple laboratories and was used here. Dissected P0 brain tissue from SwissWebster mice was lysed and sonicated in a solution containing 8M urea, reduced and alkylated with iodoacetamide, diluted to 2M urea, digested with trypsin, and peptides were desalted using solid phase extraction columns as described [9]. SCX was performed on 8mg of dried peptides as described [9] except that 16 three-minute fractions were collected. The IMAC procedure including solvents, buffers and resin were as described [9] except that we divided the desalted peptides from each fraction in half and each was subjected to a different column length of IMAC resin (10 µl or 30 µl of resin was packed in a gel loader tip column after incubation with peptides) as described [10]. After incubations in batch, the resins were packed in column formats. The peptides were again passed across the columns, and then the columns were washed and peptides were eluted from the IMAC resin as described [9]. Peptides were desalted using Stage tips [9,11] and subjected to LC-MS/MS using a linear ion trap-orbitrap hybrid mass spectrometer set up as described [12]. A total of 32 MS runs were conducted and used to search a concatenated target-decoy [13] mouse IPI database (version 3.6) using SEQUEST (Thermo Electron, Version 27, Revision 12). A total of 12,692 phosphopeptides were identified from P0 brain with a false discovery rate (FDR) of 0.45% (Supplementary Table 1). Of these, 6,380 sites were non-redundant. We compared the P0 ...

Level III-case-control study.

The efficacy of PETS may be more favorable than previously reported. Only 3.7% had serious complications requiring revision epiphysiodesis, lower than previous reports. Attention to sufficient screw threads across the physis may be important in optimizing PETS results.