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Category: Ankle, Hindfoot Introduction/Purpose: Medial displacement calcaneal osteotomies (MDCO) and first ray plantarflexion osteotomies, such as a Cotton osteotomy, are frequently used realignment procedures for hindfoot and ankle joint valgus malalignment. Multiple studies demonstrated the effects of calcaneal osteotomies on the contact pressures of the ankle joint (CPAJ), with slight medial displacement of the center of pressure and lateral unloading of the ankle joint. However, the influence of a first ray plantarflexion osteotomy on the CPAJ is yet to be determined. In this cadaveric study we compared the effects of calcaneal and first ray osteotomies in the CPAJ. Methods: Fifteen bellow-knee cadaveric specimens were dissected to expose the ankle joint and isolate the flexor and peroneal tendons. Tekscan 5033 sensors were placed in the ankle joint and held in place with cyanoacrylate. Specimens were loaded in a servohydraulic load frame. The following loads were applied to the tendons: Achilles (200 N), PTT (40 N), peroneals combined (44 N), FHL/FDL combined (35 N). Ankles were tested in an intact position, after isolated MDCO (6, 8, 10 and 12 mm), isolated Cotton osteotomies (4, 8 and 12 mm) as well as combined osteotomies (10 mm and 12 mm, respectively). Specimens were then cyclically load from 100N-700 N at a rate of 0.5 Hz for 30 cycles while CPAJ data was collected at a rate of 20 Hz. Average and maximum pressure data were extracted as well as the center of pressure (CoP) movement in the AP and ML directions. Results: There was a significant (pConclusion: The results of this study demonstrate that the Cotton osteotomy has a greater effect on the contact pressures of the ankle when compared to the MDCO. There is an overall decrease in the maximum and average pressures as well as a deviation of the center of pressure toward the anterior and lateral aspect of the ankle joint. These findings should guide surgeons when deciding between first ray and calcaneal osteotomies as realignment procedures for hindfoot and ankle valgus deformities.

HK-2 human renal proximal tubule cells (RPTC) are commonly used in the in vitro study of “normal” RPTCs. We discovered recently that HK-2 cells are uncoupled from dopamine 1 receptor (D 1 R) adenylyl cyclase (AC) stimulation. We hypothesized that G protein–coupled receptor kinase type 4 (GRK4) single nucleotide polymorphisms may be responsible for the D 1 R/AC uncoupling in HK-2. This hypothesis was tested by genotyping GRK4 single nucleotide polymorphisms, measuring D 1 -like receptor agonist (fenoldopam)-stimulated cAMP accumulation, quantifying D 1 R inhibition of sodium transport, and testing the ability of GRK4 small interfering RNA to reverse the D 1 R/AC uncoupling. We compared HK-2 with 2 normally coupled human RPTC cell lines and 2 uncoupled RPTC cell lines. The HK-2 cell line was found to have 4 of 6 potential GRK4 single nucleotide polymorphisms known to uncouple the D 1 R from AC (namely, R65L, A142V, and A486V). AC response to fenoldopam stimulation was increased in the 2 normally coupled human RPTC cell lines (FEN: 2.02±0.05-fold and 2.33±0.19-fold over control; P P

[Introduction][1] The fixation of olecranon fractures with intramedullary olecranon nails has been demonstrated to be an effective treatment option that may result in decreased soft-tissue irritation. [Step 1: Positioning and Approach][2] Proper positioning of the patient during this procedure allows for improved access to the fracture and increased accessibility for fluoroscopy. [Step 2: Reduce the Fracture][3] Reduce and provisionally hold the fracture following a limited periosteal elevation. [Step 3: Ream the Olecranon and Place the Nail][4] The olecranon is then reamed, and the intramedullary nail is inserted. [Step 4: Insert the Screw][5] Place proximal interlocking screws using the targeting system. [Step 5: Close the Wound][6] Close the wound with subdermal sutures and either staples or interrupted nylon horizontal mattress sutures. [Results][7] A total of twenty-eight patients with unstable olecranon fractures were treated with intramedullary olecranon nailing in our series, and union was achieved in all patients by eight weeks. [Indications][8] [Contraindications][9] [Pitfalls & Challenges][10] [Introduction][1] The fixation of olecranon fractures with intramedullary olecranon nails has been demonstrated to be an effective treatment option that may result in decreased soft-tissue irritation. [Step 1: Positioning and Approach][2] Proper positioning of the patient during this procedure allows for improved access to the fracture and increased accessibility for fluoroscopy. [Step 2: Reduce the Fracture][3] Reduce and provisionally hold the fracture following a limited periosteal elevation. [Step 3: Ream the Olecranon and Place the Nail][4] The olecranon is then reamed, and the intramedullary nail is inserted. [Step 4: Insert the Screw][5] Place proximal interlocking screws using the targeting system. [Step 5: Close the Wound][6] Close the wound with subdermal sutures and either staples or interrupted nylon horizontal mattress sutures. [Results][7] A total of twenty-eight patients with unstable olecranon fractures were treated with intramedullary olecranon nailing in our series, and union was achieved in all patients by eight weeks. [Indications][8] [Contraindications][9] [Pitfalls & Challenges][10] [1]: #sec-9 [2]: #sec-10 [3]: #sec-11 [4]: #sec-12 [5]: #sec-13 [6]: #sec-14 [7]: #sec-15 [8]: #sec-17 [9]: #sec-18 [10]: #sec-19