Aims

Bone metastasis ultimately occurs due to a complex multistep process, during which the interactions between cancer cells and bone microenvironment play important roles. Prior to colonization of the bone, cancer cells must succeed through a series of steps that will allow them to gain migratory and invasive properties; epithelial-to-mesenchymal transition (EMT) is known to be integral here. The aim of this study was to determine the effects of G protein subunit alpha Q (GNAQ) on the mechanisms underlying bone metastasis through EMT pathway.

Aims

Receptor activator of nuclear factor-κB ligand (RANKL) is a key molecule that is expressed in bone stromal cells and is associated with metastasis and poor prognosis in many cancers. However, cancer cells that directly express RANKL have yet to be unveiled. The current study sought to evaluate how a single subunit of G protein, guanine nucleotide-binding protein G(q) subunit alpha (GNAQ), transforms cancer cells into RANKL-expressing cancer cells.

We evaluated (1) wear rate, (2) prevalence and volume of osteolysis using 3D-CT scan, (3) other bearing-related complications, (4) HHS and survivorship free from revision at 15 years after THA using first-generation XLPE (1G XLPE).

One-hundred sixty THAs were evaluated regarding bearing-related complication, HHS and survivorship. Among them, 112 hips underwent 3D-CT to analyze wear rate and osteolysis. All THAs were performed by single surgeon using cup of identical design, a 28-mm metal head and 1G XLPE (10 Mrad). Average age were 57 years and mean follow-up was 15.2 years. 3D-CT scan was performed at average of 13.0 years. Clinical evaluation included HHS and radiographic analysis was performed regarding stem alignment, cup anteversion and inclination angle, component stability, wear rate and osteolysis. Wear was measured using digital software. The prevalence and volume of osteolysis were also evaluated. Complications included XLPE dissociation/rim fracture, dislocation, periprosthetic fracture, infection, HO and any revision. Survivorship free from revision at 15 years was estimated.

Average inclination and anteversion angle of cups were 40.7° and 20.6°. Mean stem alignment was 0.1° valgus. Average bedding-in and annual wear rate wear rate was 0.085 mm and 0.025 mm/yr. Eleven hips (10%) demonstrated osteolysis; pelvic osteolysis with average volume of 1.4 cm³ in six and femoral osteolysis with mean size of 0.4 cm² in seven hips. Of 160 THAs, 5 hips (3%) dislocated. Overall, bearing-related complications occurred in 16 hips (10%). Other complications included postoperative periprosthetic fracture in 4 (3%), infection and HO in 3 hips, respectively. No hip demonstrated loosening, XLPE rim fracture/dissociation. Seven THAs (4%) were revised; recurrent dislocation in 5 and periprosthetic joint infection in 2 hips. Average HHS at last follow-up improved from 47.7 preoperatively to 91.2 points (p<0.001). Estimated survivorship free from revision at 15 years was 95.6 %.

THA using 1G XLPE demonstrated low wear rate as well as low incidence of osteolysis at average follow-up of fifteen years. Longer-term studies will be necessary to determine if XLPE will continue to demonstrate this improved osteolysis characteristics.

Objectives

Eukaryotic translation initiation factor 3 (eIF3) is a multi-subunit complex that plays a critical role in translation initiation. Expression levels of eIF3 subunits are elevated or decreased in various cancers, suggesting a role for eIF3 in tumorigenesis. Recent studies have shown that the expression of the eIF3b subunit is elevated in bladder and prostate cancer, and eIF3b silencing inhibited glioblastoma growth and induced cellular apoptosis. In this study, we investigated the role of eIF3b in the survival of osteosarcoma cells.

Introduction: The amount of tension which surgeons apply to a two-side Dall-Miles cable during the fixation of periprosthetic fracture has not been reported. Current study is the first report that reveals the real cable tension data which was intraoperatively measured.

Methods: In vivo data of tightening torque was measured intraoperatively during Dall-Miles cable fixation surgeries for periprosthetic fracture of the femur. And the numerical relationship between torque and cable tension was assessed through mechanical tests. Using the torque vs. cable tension relationship, intraoperatively measured tightening torque was converted into a cable tension.

Intraoperative measurement of tightening torque In vivo data of the maximal torque which was applied by an experienced surgeon was measured using a torquemeter. Total 11 cases of periprosthetic femoral fractures from 11 patients were participated with their agreement. A two-side Dall-Miles cable tightener (Stryker Co., USA) was used. To measure the torque of Dall-Miles tightener applied by a surgeon, a torquemeter (Torque driver 80FTD2-N-S, TOHNICHI, JAPAN) was connected to the Dall-Miles tightener through a square groove. The groove was machined with 1cm × 1cm × 1cm in dimension on the proximal end of the rotational shaft of the Dall-Miles tightener.

Laboratory measurement of torque and tension To reveal the relationship between the torque of Dall-Miles cable tensioner and the tension of the cable, mechanical tests were done. A two-side Dall-Miles cable tightener were mounted to INSTRON (INSTRON, Norwood, MA, USA) using a customized fixation jig. One cable of 2 mm in diameter was connected to the upper head of INSTRON, and another to the lower headA preload was slowly applied to the cables up to 10 N so that the initially loose interaction among a tightener, two cables, and two loading heads of INSTRON became tight. Once the preloading finished, tightening torque and cable tension were simultaneously measured. The tightening torque was increased in increment of 1 N-m; accordingly, at each torque the tension hung to Dall-Miles cable was measured by reading loadcell data of INSTRON.

Results: Intraoperative tightening torque Intraoperatively measured maximal torque applied to the Dall-Miles cable tensioner was 5.7±0.5 N-m.

Numerical expression of torque-tension relationship Based on the data of tightening torque and cable tension measured from mechanical tests, the relationship between the torque (T) and tension (P) of Dall-Midles cable fixation system was numerically expressed. Total range of measured tightening torques and cable tensions was linearized. The linear expression was “T=106.8 × P”. Based on this numerical relationship, the amount of cable tension applied to the cable was calculated as 606.6±58 N.

Discussion: This study revealed that 606.6±58 N of cable tension has been applied when an experienced surgeon does cable fixation of periprosthetic fracture. Authors believe that the torque-tension relationship will provide a key biomechanical clue for biomechanics scientists, and the amount of intraoperative cable tension measured at the time of Dall-Miles cable fixation for periprosthetic fracture will provide an important surgical key reference for the surgeons who use the cable fixation system.