Background: The tibial tubercle to trochlear groove (TT-TG) distance is often utilized for determining the surgical treatment for patients with patellar instability (PI). It is thought to directly represent the position of the TT on the tibia. Recent work has shown that the measurement of the TT-TG distance is multifactorial. Purpose: To investigate the relationship between relative tibial external rotation (rTER) and trochlear dysplasia (TD), as well as the location of the TG and TT in patients with and without PI, and to correlate these and other anatomic measurements with the TT-TG distance. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 89 patients with PI who underwent magnetic resonance imaging were identified with 92 matched control patients. A standardized measurement protocol on axial magnetic resonance imaging determined rTER, the proximal and distal TG lateralization (pTGL and dTGL, respectively) ratios, and the TT lateralization (TTL) ratio. Other measures of interest included the lateral trochlear inclination angle, sulcus angle, and lateral patellar inclination angle. Univariate regression was used to determine the associations of TD (lateral trochlear inclination angle, sulcus angle) with rTER and the TG position, and multivariate regression was used to model associations among all the variables with the proximal and distal TT-TG distances. Results: rTER was significantly higher in the study group ( P < .001), and univariate regression showed a significant association between dysplasia measures and rTER ( P < .001). The pTGL ratio was lower in the study group ( P = .025), but there was no difference in the dTGL ratio ( P = .090) or the TTL ratio ( P = .098) between the groups. There were no associations between dysplasia measures and the pTGL and dTGL ratios ( P > .05). Multivariate regression showed that the proximal TT-TG distance is predicted by the sulcus angle, pTGL ratio, rTER, and TTL ratio ( P < .05) and that the distal TT-TG distance is predicted by the lateral patellar inclination angle, dTGL ratio, sulcus angle, rTER, and TTL ratio ( P < .05). Conclusion: rTER had a significant association with TD. The position of the proximal TG was more medial in patients with PI. There was no significant difference in the TTL ratio between patients with and without PI. The TT-TG distance was associated with multiple anatomic measures and was not solely predicated on the position of the TT.

Introduction Sciatic hernias are the rarest form of pelvic floor hernias as well as an uncommon cause of sciatica. A high index of suspicion is required to make the diagnosis due to its variable clinical presentation. This is the first case describing bilateral intestinal sciatic hernia, diagnosis, and robotic surgical repair. Presentation of case A 77-year-old female with history of chronic back pain and diverticulitis presented with three weeks of abdominal pain, radiating down her legs bilaterally. Computed tomography (CT) revealed bilateral sciatic notch hernias without evidence of bowel obstruction. Magnetic resonance imaging (MRI) confirmed compression of the sciatic nerves within the sciatic notch bilaterally. She underwent robotic bilateral retroperitoneal sciatic notch hernia repair successfully. Discussion There are several independent causes of abdominal pain and bilateral radiating leg pain. Sciatic hernias are an unusual cause of both. Aside from bowel, the hernia can involve other structures, such as the bladder, ureters, or ovaries, potentially creating drastically different clinical pictures. Laparoscopic or robotic repair have been proven superior to open surgery in the literature. Conclusion This case demonstrates that bilateral sciatic hernias can present as uncomplicated sciatica in an elderly patient, but the addition of seemingly unrelated abdominal pain should warrant further investigation. Minimally invasive robotic repair can successfully treat sciatic hernias.

The treatment of scoliosis has been explored and debated in medicine since the first recorded texts. Scoliosis treatment has shifted over time from external modalities, such as traction and bracing, to internal stabilization techniques that leverage surgical advances. Surgical fixation constructs can generally be separated into two different modalities: dynamic vs. static constructs. For skeletally immature individuals with progressive deformities, surgical options range from traditional or magnetically controlled growing rods to vertebral body staples or tethering. For individuals who have reached skeletal maturity, many devices have been developed that provide static length constructs. Understanding the surgical options available is critical for the appropriate management of this varied patient population. With this article, we sought to provide a summary of past and present techniques and devices used in the treatment of scoliosis.

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Category: Ankle; Basic Sciences/Biologics; Other Introduction/Purpose: The purpose of this study was to evaluate the presence of connective tissue progenitor cells within the retrocalcaneal bursa. The study evaluation included an assessment of the viability of connective tissue progenitor cells, their proliferative potential, and their ability to differentiate into osteoblasts, adipocytes, and chondrocytes. Methods: The retrocalcaneal bursa samples were excised from 10 patients (age: 51.5 +- 10.8 years) undergoing Achilles surgery in which the retrocalcaneal bursa is routinely excised. Bursal tissue was processed by digesting cells with collagenase and obtaining nucleated cell counts and cellular concentrations. The cells were cultured, and differentiated into osteoblasts, adipocytes, and chondrocytes. Analysis of bursal derived cells consisted of fluorescent activated cell sorting (FACS) analysis, cellular proliferation and viability assay, and analysis of differentiation into osteoblasts, adipocytes, and chondrocytes. The CTP differentiation was confirmed using histology staining to qualitatively express differentiation, and qPCR to quantify gene expression. Results: Cell migration at 3 weeks on average was found to be 3.84x107 nucleated cells/gram of tissue and nucleated cellular concentration on average was found to be 6.28x105 cells/mL of suspension. The proliferation data showed high levels of proliferation on average of 1.72 +-0.58. The FACS analysis showed a high percentage of positive surface markers for CTPs measuring greater than 96% (CD105, CD90, CD73) and measuring < 1.1% for negative surface markers (CD45 and CD31). Differentiation into osteoblasts, adipocytes, and chondrocytes were stained appropriately displaying differentiation. Conclusion: The retrocalcaneal bursa is a novel source of connective tissue progenitor cells. This is the first study to our knowledge analyzing the retrocalcaneal bursa as a novel source for CTPs, making it a potential augment to expedite the healing process of the Achilles tendon. Overall, it is unclear what the role of the CTPs within the bursa is, however, they may help to reduce the extensive healing time for the Achilles tendon thereby returning patients with Achilles tendon pathology back to functional status more promptly.