Background: There is evidence that femoroacetabular impingement (FAI) is increasingly prevalent among adolescent athletes. Abnormal contact forces across the hip and alterations in bony morphology characteristic of FAI may be especially detrimental in this group, given their young age and active lifestyle. Purpose: The purpose of this study was to report the findings, outcomes, and return to sport percentage among adolescent athletes with FAI treated with hip arthroscopy. Methods: A retrospective review of all patients younger than 18 years who underwent hip arthroscopy for FAI at a single institution was performed. All athletes who were attempting to return to sport and underwent hip arthroscopy were included. Patients with previous hip surgery and/or hip conditions were excluded. Arthroscopic procedures and an assessment of intra-articular findings were recorded. Patient-reported outcome measures were recorded at 3 months, 1 year, and 2 years postoperatively, and included the modified Harris hip score, the nonarthritic hip score, hip outcome score—sports subscale, visual analogue scale for pain, and patient satisfaction. Return to sport percentage and ability levels were also noted. Results: There were 96 eligible cases of adolescent athletes treated with hip arthroscopy; 81 (84.4%) hips in 69 patients had 2-year follow-up. Running/track and field was the most common sport (25), followed by soccer (12), dance (10), baseball/softball (9), and basketball (6). There were 61 females and 20 males, whose average age was 15.9±1.2 y (range: 13.1 to 18.0 y). The most common procedures were labral repair (81.5%), iliopsoas fractional lengthening (72.8%), femoroplasty (69.1%), and acetabuloplasty (66.7%). Capsular repair or plication was performed in most patients (81.5%). Cartilage damage was more common on the acetabulum than the femur, with Outerbridge grade 2 or higher occurring in 23.5% and 4.9% of hips, respectively. Statistically significant improvements were seen in all patient-reported outcomes from preoperative to minimum 2-year follow-up. A total of 84.0% of patients had returned to their sport at latest follow-up. There were 6 (7.4%) patients who underwent revision arthroscopy at a mean of 37.3 months postoperatively. Conclusion: Symptomatic FAI in adolescent athletes can be successfully treated with hip arthroscopy, with a higher return to sport rate and low complications and reoperation rate at minimum 2-year follow-up.

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Learning and memory are fundamental processes that are disrupted in many neurological disorders including Alzheimer’s disease and epilepsy. The hippocampus plays an integral role in these functions, and modulation of synaptic transmission mediated by γ-aminobutyric acid (GABA) type-A receptors (GABAARs) impacts hippocampus-dependent learning and memory. The protein diazepam binding inhibitor (DBI) differentially modulates GABAARs in various brain regions, including hippocampus, and changes in DBI levels may be linked to altered learning and memory. The effects of genetic loss of DBI signaling on these processes, however, have not been determined. In these studies, we examined male and female constitutive DBI knockout mice and wild-type littermates to investigate the role of DBI signaling in modulating multiple forms of hippocampus-dependent spatial learning and memory. DBI knockout mice did not show impaired discrimination of objects in familiar and novel locations in an object location memory test, but did exhibit reduced time spent exploring the objects. Multiple parameters of Barnes maze performance, testing the capability to utilize spatial reference cues, were disrupted in DBI knockout mice. Furthermore, whereas most wild-type mice adopted a direct search strategy upon learning the location of the target hole, knockout mice showed higher rates of using an inefficient random strategy. In addition, DBI knockout mice displayed typical levels of contextual fear conditioning, but lacked a sex difference observed in wild-type mice. Together, these data suggest that DBI selectively influences certain forms of spatial learning and memory, indicating novel roles for DBI signaling in modulating hippocampus-dependent behavior in a task-specific manner.

Patellar tendon ruptures are the third most common injury to the extensor mechanism. These injuries are debilitating to the patient, and delays in treatment can present a challenge to the treating surgeon. Chronic patellar tendon injuries are rare and are more difficult to manage given proximal patellar retraction, scarring, and atrophy of surrounding tissues. There is no consensus on the optimal approach for treatment, and numerous reconstruction techniques have been described using a variety of graft choices and fixation methods. We describe our surgical technique for a 3-fold reconstruction of a chronic patellar tendon rupture using an Achilles tendon allograft augmented with a vascularized ipsilateral hamstring tendon autograft and additional FiberTape augmentation. The aim of this procedure is to restore patellar height and prevent extensor lag.

Astrocytes play active roles at synapses and can monitor, respond, and adapt to local synaptic activity. Although there is growing evidence that astrocytes modulate synaptic excitation, the extent to which astrocytes modulate inhibition remains unknown. Additionally, tools that can selectively activate native G protein signaling pathways in astrocytes with both spatial and temporal precision are needed. Here, we present AAV8-GFAP-Optoα1AR-eYFP (Optoα1AR), an astrocyte-specific viral vector that activates the Gq-mediated intracellular cascade via light-sensitive α1-adrenergic receptors. To determine if stimulation of Optoα1AR in astrocytes modulates hippocampal synaptic transmission, whole-cell recordings were made in CA1 pyramidal cells in slices with surrounding astrocytes expressing either Optoα1AR, channelrhodopsin (ChR2), or control green fluorescent protein (GFP). CA1 astrocytes were exposed to either low-frequency (0.5 Hz, 1-s pulses at increasing 1, 5, and 10 mW intensities, 90 s/intensity) or high-frequency (20 Hz, 45-ms light pulses, 5 mW, 5 min) blue light stimulation. Low-frequency stimulation of astrocytic Optoα1AR was insufficient to modulate the frequency or strength of either inhibitory or excitatory spontaneous postsynaptic currents (sIPSCs/sEPSCs), whereas the same stimulation of astrocytic ChR2 produced increases in sIPSC frequency and sEPSC frequency and amplitude. By contrast, 20 Hz stimulation of astrocytic Optoα1AR increased frequency of both miniature IPSCs and EPSCs, and the miniature IPSC frequency effect was largely reversible within 20 min after light stimulation. These data demonstrate that Optoα1AR activation in astrocytes changes basal GABAergic and glutamatergic transmission but only following high-frequency stimulation, highlighting the importance of temporal dynamics when using optical tools to manipulate astrocyte function.Significance statementAstrocytes are critical components of synapses and are known to modulate glutamatergic synaptic transmission. However, the extent to which astrocytes modulate basal GABAergic transmission is less clear. Additionally, there is demand for tools that can activate physiologically-relevant signaling pathways in astrocytes with improved temporal precision. Here, we present a novel optogenetic viral vector, AAV8-GFAP-Optoα1AR-eYFP, to stimulate astrocytes with improved temporal control. We report that high-frequency (20 Hz) stimulation of astrocytic Optoα1AR produces changes in inhibitory and excitatory transmission in hippocampal CA1, but low-frequency stimulation (0.5 Hz) is insufficient. These findings suggest that astrocytes are sensitive to the temporal dynamics of optical stimulation, and reinforce the importance of careful consideration of stimulation paradigm when using optogenetic tools to manipulate astrocytic function.