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Bone & Joint Open
Vol. 3, Issue 3 | Pages 211 - 217
1 Mar 2022
Hsu C Chen C Wang S Huang J Tong K Huang K

Aims

The Coronal Plane Alignment of the Knee (CPAK) classification is a simple and comprehensive system for predicting pre-arthritic knee alignment. However, when the CPAK classification is applied in the Asian population, which is characterized by more varus and wider distribution in lower limb alignment, modifications in the boundaries of arithmetic hip-knee-ankle angle (aHKA) and joint line obliquity (JLO) should be considered. The purposes of this study were as follows: first, to propose a modified CPAK classification based on the actual joint line obliquity (aJLO) and wider range of aHKA in the Asian population; second, to test this classification in a cohort of Asians with healthy knees; third, to propose individualized alignment targets for different CPAK types in kinematically aligned (KA) total knee arthroplasty (TKA).

Methods

The CPAK classification was modified by changing the neutral boundaries of aHKA to 0° ± 3° and using aJLO as a new variable. Radiological analysis of 214 healthy knees in 214 Asian individuals was used to assess the distribution and mean value of alignment angles of each phenotype among different classifications based on the coronal plane. Individualized alignment targets were set according to the mean lateral distal femoral angle (LDFA) and medial proximal tibial angle (MPTA) of different knee types.


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_16 | Pages 74 - 74
1 Dec 2021
Chen H Khong J Huang J
Full Access

Abstract

Objectives

Direct ink writing (DIW) has gained considerable attention in production of personalized medical implants. Laponite nanoclay is added in polycaprolactone (PCL) to improve printability and bioactivity for bone implants. The 3D structure of DIW printed PCL/Laponite products was qualitatively evaluated using micro-CT.

Methods

PCL/LP composite ink was formulated by dissolving 50% m/v PCL in dichloromethane with Laponite loading of up to 30%. The rheological properties of the inks were determined using Discovery HR-2 rheometer. A custom-made direct ink writer was used to fabricate both porous scaffold with 0°/90° lay-down pattern, and solid dumbbell-shaped specimens (ASTM D638 Type IV) with two printing orientations, 0° and 90° to the loading direction in tensile testing. The 3D structure of specimens was assessed using a micro-CT. Independent t-tests were performed with significance level at p<0.05.


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_2 | Pages 51 - 51
1 Mar 2021
Zhang B Nguyen A Narayan R Huang J
Full Access

Abstract

3D printing of synthetic scaffolds mimicking natural bone chemical composition, structure, and mechanical properties is a promising approach for repairing bone injuries. Direct ink writing (DIW), a type of 3D printing, confers compatibility with a wide range of materials without exposing these materials to extreme heat. Optimizing ink properties such as filament formation capabilities, shear-thinning, and high storage modulus recovery would improve DIW fabrication characteristics. In this study, composite inks based on biodegradable polycaprolactone (PCL), reinforced with nano-hydroxyapatite (HAp), and loaded with vancomycin were designed and evaluated for their rheological properties, wettability, mechanical properties, and antimicrobial properties. The formulated composite inks displayed a shear-thinning behaviour exhibited storage modulus recovery percentages above 80% for all formulations, which is essential for extrusion deposition by DIW at room temperature. Ink formulations were able to form fully interconnected lattice scaffolds with porosities ranging from 42% to 65%. Increasing the HAp concentrations from 55% to 85% w/w increased the shear thinning behaviour and reduced the printed filament width to more closely match the nozzle diameter; this indicates higher HAp proportion reduces ink shrinkage. The scaffold had high wettability at HAp proportions above 65% w/w and the compressive elastic modulus of DIW printed scaffolds exhibited within the range of trabecular bone. Antimicrobial activity was apparent from the agar diffusion assay; zones of inhibition ranging from 15.82 ± 0.25 mm and 20.06 ± 0.25 mm were observed after 24 hr for composite scaffolds loaded with 3% and 9% w/w vancomycin respectively. Vancomycin-loaded PCL/HAp composite inks were developed, displaying good printability, wettability, mechanical properties, and antimicrobial properties, making them an attractive choice for bone repair and regeneration.

Declaration of Interest

(b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_2 | Pages 96 - 96
1 Mar 2021
Chen H Stampoultzis T Papadopoulou A Balabani S Huang J
Full Access

Abstract

Objectives

The objective of this study is to investigate the effect of solvents and rheological properties of PCL/Hydroxyapatite ink on the shape fidelity of the 3D printed scaffolds for bone tissue engineering.

Methods

A series of inks were made consisting of 50% (w/v) of polycaprolactone (PCL) filled with 0%, 3.5% and 12.5% (w/V) of hydroxyapatite (HA) in dichloromethane (DCM) and chloroform (CHF). Steady and oscillatory shear rheological tests were performed on a rheometer (Discovery HR-3). Solvent-cast direct ink writing was performed with a custom-made 3D printer for the fabrication of PCL/HA scaffold structures with 2–8 layers. Optical microscope and scanning electron microscopy (SEM) were used to assess the shape fidelity.


Bone & Joint Research
Vol. 10, Issue 1 | Pages 10 - 21
1 Jan 2021
Zong Z Zhang X Yang Z Yuan W Huang J Lin W Chen T Yu J Chen J Cui L Li G Wei B Lin S

Aims

Ageing-related incompetence becomes a major hurdle for the clinical translation of adult stem cells in the treatment of osteoarthritis (OA). This study aims to investigate the effect of stepwise preconditioning on cellular behaviours in human mesenchymal stem cells (hMSCs) from ageing patients, and to verify their therapeutic effect in an OA animal model.

Methods

Mesenchymal stem cells (MSCs) were isolated from ageing patients and preconditioned with chondrogenic differentiation medium, followed by normal growth medium. Cellular assays including Bromodeoxyuridine / 5-bromo-2'-deoxyuridine (BrdU), quantitative polymerase chain reaction (q-PCR), β-Gal, Rosette forming, and histological staining were compared in the manipulated human mesenchymal stem cells (hM-MSCs) and their controls. The anterior cruciate ligament transection (ACLT) rabbit models were locally injected with two millions, four millions, or eight millions of hM-MSCs or phosphate-buffered saline (PBS). Osteoarthritis Research Society International (OARSI) scoring was performed to measure the pathological changes in the affected joints after staining. Micro-CT analysis was conducted to determine the microstructural changes in subchondral bone.


Bone & Joint Research
Vol. 8, Issue 10 | Pages 481 - 488
1 Oct 2019
Nathan K Lu LY Lin T Pajarinen J Jämsen E Huang J Romero-Lopez M Maruyama M Kohno Y Yao Z Goodman SB

Objectives

Up to 10% of fractures result in undesirable outcomes, for which female sex is a risk factor. Cellular sex differences have been implicated in these different healing processes. Better understanding of the mechanisms underlying bone healing and sex differences in this process is key to improved clinical outcomes. This study utilized a macrophage–mesenchymal stem cell (MSC) coculture system to determine: 1) the precise timing of proinflammatory (M1) to anti-inflammatory (M2) macrophage transition for optimal bone formation; and 2) how such immunomodulation was affected by male versus female cocultures.

Methods

A primary murine macrophage-MSC coculture system was used to demonstrate the optimal transition time from M1 to M2 (polarized from M1 with interleukin (IL)-4) macrophages to maximize matrix mineralization in male and female MSCs. Outcome variables included Alizarin Red staining, alkaline phosphatase (ALP) activity, and osteocalcin protein secretion.


Bone & Joint Research
Vol. 8, Issue 8 | Pages 405 - 413
1 Aug 2019
Huang J Bao X Xia W Zhu L Zhang J Ma J Jiang N Yang J Chen Q Jing T Liu J Ma D Xu G

Objectives

X-linked hypophosphataemic rickets (XLHR) is a disease of impaired bone mineralization characterized by hypophosphataemia caused by renal phosphate wasting. The main clinical manifestations of the disorder are O-shaped legs, X-shaped legs, delayed growth, and bone pain. XLHR is the most common inheritable form of rickets, with an incidence of 1/20 000 in humans. It accounts for approximately 80% of familial cases of hypophosphataemia and serves as the prototype of defective tubular phosphate (PO43+) transport, due to extra renal defects resulting in unregulated FGF23 activity. XLHR is caused by loss-of-function mutations in the PHEX gene. The aim of this research was to identify the genetic defect responsible for familial hypophosphataemic rickets in a four-generation Chinese Han pedigree and to analyze the function of this mutation.

Methods

The genome DNA samples of all members in the pedigree were extracted from whole blood. We sequenced all exons of the PHEX and FGF23 genes, as well as the adjacent splice site sequence with Sanger sequencing. Next, we analyzed the de novo mutation c.1692 del A of the PHEX gene with an online digital service and investigated the mutant PHEX with SWISS-MODEL, immunofluorescence, and protein stability detection.


Bone & Joint Research
Vol. 7, Issue 12 | Pages 629 - 635
1 Dec 2018
Hung L Chao C Huang J Lin J

Objectives

Screw plugs have been reported to increase the fatigue strength of stainless steel locking plates. The objective of this study was to examine and compare this effect between stainless steel and titanium locking plates.

Methods

Custom-designed locking plates with identical structures were fabricated from stainless steel and a titanium alloy. Three types of plates were compared: type I unplugged plates; type II plugged plates with a 4 Nm torque; and type III plugged plates with a 12 Nm torque. The stiffness, yield strength, and fatigue strength of the plates were investigated through a four-point bending test. Failure analyses were performed subsequently.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 291 - 291
1 Jul 2014
Ding Y Huang J Huang D Shen H
Full Access

Summary

RNAi targeting p110β reduces TNF-alpha production and osteolysis in response to wear particles.

Introduction

Aseptic joint loosening is a key factor that reduces the life span of joint prosthesis. Prosthetic wear particles are thought to play a central role in the initiation and development of periprosthetic osteolysis, leading to aseptic loosening of prostheses. This study aims to explore the effect of p110β-targeted small interfering RNA (siRNA) and lentivirus on particle-induced inflammatory cytokine expression in murine macrophage.


Bone & Joint Research
Vol. 2, Issue 12 | Pages 255 - 263
1 Dec 2013
Zhang Y Xu J Wang X Huang J Zhang C Chen L Wang C Ma X

Objective

The objective of this study was to evaluate the rotation and translation of each joint in the hindfoot and compare the load response in healthy feet with that in stage II posterior tibial tendon dysfunction (PTTD) flatfoot by analysing the reconstructive three-dimensional (3D) computed tomography (CT) image data during simulated weight-bearing.

Methods

CT scans of 15 healthy feet and 15 feet with stage II PTTD flatfoot were taken first in a non-weight-bearing condition, followed by a simulated full-body weight-bearing condition. The images of the hindfoot bones were reconstructed into 3D models. The ‘twice registration’ method in three planes was used to calculate the position of the talus relative to the calcaneus in the talocalcaneal joint, the navicular relative to the talus in talonavicular joint, and the cuboid relative to the calcaneus in the calcaneocuboid joint.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXV | Pages 182 - 182
1 Jun 2012
Patel B Edirisinghe M Inam F Reece M Bonfield W Huang J Angadji A
Full Access

Millions of people suffer from bone and joint inflammatory problems and usually result in extreme cases with total joint replacement. Most commonly affected joints are the hip and the knee. Over the past 20 years there has been a revival in interest of metal-on-metal hip replacements. Various alloys have been used in joint replacement, the most successful in the Cobalt-based alloys. As compared to others the cobalt based alloys have higher wear resistance and therefore less risk of failure. The most common Co-based alloy used in clinical application is the ASTM F75 alloy, which is extensively used in femoral and acetabular components. Conventional methods to fabricate the alloy are via cast or wrought techniques. Wrought alloys are better than their cast materials due to their superior mechanical properties as the forging process promotes plastic deformation. An alternative method of fabrication is via powder processing and has shown significant improvements to produce finer grained materials, which relate to enhancement in properties, such as strength, toughness, ductility.

One of the key stages of powder processing is sintering of the powder to fuse the particles together. A superior but simple sintering processing is spark plasma sintering (SPS), which produces highly dense materials with minimum grain growth. This is achieved by a pulsed electrical current heating the material while applying a pressure to compact the powdered material. This process has the ability to densify nanopowders, in order to produce microstructures with finer grains and superior mechanical properties.

Using SPS and nanopowders for the first time, we have been able to prepare the ASTM F75 cobalt–chromium–molybdenum (Co–Cr–Mo) orthopaedic alloy composition. In this work we have investigated, the effect of processing variables on the structural features of the alloy (phases present, grain size and microstructure). We have been able to produce specimens of >99% of the theoretical density. The structures were free of carbides, which a vital breakthrough. Detrimental carbide phases in the microstructure as found in the more conventional methods of fabrication have shown to cause problems in wear. The compacts are of higher hardness than cast or wrought products despite the absence of carbides in the microstructure. The gain in hardness is because of the presence of oxides in the microstructure and we hope to quantify the oxide content in the future. The mechanisms of oxide formation are explained by considering chemical thermodynamics and kinetics. The next step is to evaluate the tribological performance (wear, friction, lubrication regimes) of this SPS-processed material and compare its performance with conventional MoM products (cast and wrought). The SPS route offers significant advantages over the conventional cast and wrought routes used to prepare this alloy for orthopaedic applications.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_IV | Pages 25 - 25
1 Mar 2012
Altman G Horan R Weitzel P Horan D Mortarino E DeAngelis N Toponarski I Huang J Boepple H Prudom J Richmond J
Full Access

Objectives

We hypothesise that a long-term bioresorbable hydrophilic silkworm silk device, the SeriACL(tm) scaffold, can support the development and remodelling of native functional ligament tissue if designed to anticipate the remodelling curve of an ACL graft. This study evaluated the SeriACL scaffold for ACL replacement in a goat model at 3, 6 and 12 months.

Methods

The ACL of 43 goats was replaced in an arthroscopically assisted procedure. The ACL was excised, a guide pin driven into the femur and 6mm diameter antegrade drilling performed. The tibial tunnel was drilled under direct visualisation. The graft was anchored around a post on the femur, tensioned to 50N and cycled 30x before tibial fixation with a staple and sutures around a post. Animals were clinically, mechanically and histologically evaluated.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_II | Pages 288 - 288
1 May 2009
Horan RL Richmond JC Weitzel PP Horan DJ Mortarino E DeAngelis N Toponarski I Huang J Boepple H Prudom J Altman GH
Full Access

Objectives: Advances in biomedical engineering have led to a thorough understanding of the body’s own capacity for ACL healing if provided the correct impetus—a long-term bioresorbable graft scaffold that anticipates the defect site’s biological and mechanical requirements. We hypothesize that by providing a structural scaffold which anticipates ACL repair mechanisms, “engineered” autologous ligament with excellent functional integrity can be developed by the body itself. This study evaluated the SeriACL™ graft, a non-mammalian derived long-term bioresorbable multi-bundled silk-based implant, for ACL replacement in a goat model at 3, 6 and 12 months post-operatively.

Methods: The ACL of 43 goats was replaced with the SeriACL graft in an arthroscopically assisted procedure. The ACL was excised, a guide pin driven into the femur and 6mm diameter antegrade drilling performed. The tibial tunnel was drilled under direct visualization. The SeriACL, designed to mimic hamstring grafts, was anchored around a post on the femur. The graft was tensioned to 50N and cycled 30x before tibial fixation with a staple and sutures around a post. Animals were clinically, mechanically and histomorphometrically evaluated at 3, 6 and 12 months.

Results: The SeriACL graft or surgical procedure did not induce early signs of acute inflammation, swelling or initial scar formation as indicated by rapidly declining scores for pain and knee size. All animals were weight bearing at 3, 6 and 12 months, with 95% returning to normal gait by 6 months. Lachmann showed the majority of knees were clinically stable at all points. Range of motion assessment indicated the knees maintained a normal range flexion and extension at all points. No gross cartilaginous damage, synovitis or particulate debris in lymph nodes was observed at any time point. Organized collagen and aligned fibroblasts in a crimp pattern were observed in the periphery of the ligament structure, adjacent to and attached to the remaining SeriACL device at all necropsy times. Collagen development throughout the graft and bone tunnels increased with time. Conversely, inflammation and device mass loss decreased with time. Fluoroscopy indicated no abnormal bone tunnel findings. Total plasma IgG levels did not increase from pre-surgery levels at any time. AP laxity indicated joint stability at all time points. Implant abrasion was observed to varying extents yet mechanical testing revealed tissue development supported increased load bearing over time.

Conclusions: Results clearly demonstrate the potential of a scaffold-first strategy in engineering viable autologous ACL tissue that may serve over the patient’s life time. The SeriACL graft supported autologous development of a mechanically robust, biologically viable ligament which stabilized the joint over a 12 mo period. Mechanical, clinical and histological results indicated the safety of the SeriACL with initial indications of efficacy. Thus, the implant may offer the potential of an ACL replacement graft without the deleterious side-effects associated with donor-site morbidity and allogenic and xenogenic grafts.