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Fulltext Comparison of various functionally graded femoral prostheses by finite element analysis

Oshkour AA, Talebi H, Shirazi SF, Bayat M, Yau YH, Tarlochan F, et al.

ScientificWorldJournal, 2014;2014:807621.
PMID: 25302331 DOI: 10.1155/2014/807621

This study is focused on finite element analysis of a model comprising femur into which a femoral component of a total hip replacement was implanted. The considered prosthesis is fabricated from a functionally graded material (FGM) comprising a layer of a titanium alloy bonded to a layer of hydroxyapatite. The elastic modulus of the FGM was adjusted in the radial, longitudinal, and longitudinal-radial directions by altering the volume fraction gradient exponent. Four cases were studied, involving two different methods of anchoring the prosthesis to the spongy bone and two cases of applied loading. The results revealed that the FG prostheses provoked more SED to the bone. The FG prostheses carried less stress, while more stress was induced to the bone and cement. Meanwhile, less shear interface stress was stimulated to the prosthesis-bone interface in the noncemented FG prostheses. The cement-bone interface carried more stress compared to the prosthesis-cement interface. Stair climbing induced more harmful effects to the implanted femur components compared to the normal walking by causing more stress. Therefore, stress shielding, developed stresses, and interface stresses in the THR components could be adjusted through the controlling stiffness of the FG prosthesis by managing volume fraction gradient exponent.

Matched MeSH terms: Prosthesis Design/instrumentation; Prosthesis Design/methods*
Fulltext Comparative study between Dermo, Pelite, and Seal-In X5 liners: effect on patient's satisfaction and perceived problems

Ali S, Abu Osman NA, Arifin N, Gholizadeh H, Abd Razak NA, Abas WA

ScientificWorldJournal, 2014;2014:769810.
PMID: 25184154 DOI: 10.1155/2014/769810

This study aimed to compare the effect of satisfaction and perceived problems between Pelite, Dermo with shuttle lock, and Seal-In X5 liners on the transtibial amputees.

Matched MeSH terms: Prosthesis Design*
Fulltext Technology efficacy in active prosthetic knees for transfemoral amputees: a quantitative evaluation

El-Sayed AM, Hamzaid NA, Abu Osman NA

ScientificWorldJournal, 2014;2014:297431.
PMID: 25110727 DOI: 10.1155/2014/297431

Several studies have presented technological ensembles of active knee systems for transfemoral prosthesis. Other studies have examined the amputees' gait performance while wearing a specific active prosthesis. This paper combined both insights, that is, a technical examination of the components used, with an evaluation of how these improved the gait of respective users. This study aims to offer a quantitative understanding of the potential enhancement derived from strategic integration of core elements in developing an effective device. The study systematically discussed the current technology in active transfemoral prosthesis with respect to its functional walking performance amongst above-knee amputee users, to evaluate the system's efficacy in producing close-to-normal user performance. The performances of its actuator, sensory system, and control technique that are incorporated in each reported system were evaluated separately and numerical comparisons were conducted based on the percentage of amputees' gait deviation from normal gait profile points. The results identified particular components that contributed closest to normal gait parameters. However, the conclusion is limitedly extendable due to the small number of studies. Thus, more clinical validation of the active prosthetic knee technology is needed to better understand the extent of contribution of each component to the most functional development.

Matched MeSH terms: Prosthesis Design
Fulltext Review of the socket design and interface pressure measurement for transtibial prosthesis

Pirouzi G, Abu Osman NA, Eshraghi A, Ali S, Gholizadeh H, Wan Abas WA

ScientificWorldJournal, 2014;2014:849073.
PMID: 25197716 DOI: 10.1155/2014/849073

Socket is an important part of every prosthetic limb as an interface between the residual limb and prosthetic components. Biomechanics of socket-residual limb interface, especially the pressure and force distribution, have effect on patient satisfaction and function. This paper aimed to review and evaluate studies conducted in the last decades on the design of socket, in-socket interface pressure measurement, and socket biomechanics. Literature was searched to find related keywords with transtibial amputation, socket-residual limb interface, socket measurement, socket design, modeling, computational modeling, and suspension system. In accordance with the selection criteria, 19 articles were selected for further analysis. It was revealed that pressure and stress have been studied in the last decaeds, but quantitative evaluations remain inapplicable in clinical settings. This study also illustrates prevailing systems, which may facilitate improvements in socket design for improved quality of life for individuals ambulating with transtibial prosthesis. It is hoped that the review will better facilitate the understanding and determine the clinical relevance of quantitative evaluations.

Matched MeSH terms: Prosthesis Design/methods*
Fulltext Mechanism and design analysis of articulated ankle foot orthoses for drop-foot

Alam M, Choudhury IA, Bin Mamat A

ScientificWorldJournal, 2014;2014:867869.
PMID: 24892102 DOI: 10.1155/2014/867869

Robotic technologies are being employed increasingly in the treatment of lower limb disabilities. Individuals suffering from stroke and other neurological disorders often experience inadequate dorsiflexion during swing phase of the gait cycle due to dorsiflexor muscle weakness. This type of pathological gait, mostly known as drop-foot gait, has two major complications, foot-slap during loading response and toe-drag during swing. Ankle foot orthotic (AFO) devices are mostly prescribed to resolve these complications. Existing AFOs are designed with or without articulated joint with various motion control elements like springs, dampers, four-bar mechanism, series elastic actuator, and so forth. This paper examines various AFO designs for drop-foot, discusses the mechanism, and identifies limitations and remaining design challenges. Along with two commercially available AFOs some designs possess promising prospective to be used as daily-wear device. However, the design and mechanism of AFO must ensure compactness, light weight, low noise, and high efficiency. These entailments present significant engineering challenges to develop a new design with wide consumer adoption.

Matched MeSH terms: Prosthesis Design*
Multidisciplinary treatment approach to restore deep horizontally fractured maxillary central incisor

Patil PG, Nimbalkar-Patil SP, Karandikar AB

J Contemp Dent Pract, 2014 Jan 1;15(1):112-5.
PMID: 24939276

This case report demonstrates sequential periodontic, orthodontic and prosthodontic treatment modalities to save and restore deep horizontally fractured maxillary central incisor. The location of fracture was deep in the mucosa which reveals less than 2 mm of tooth structure to receive the crown. The procedures like surgical crown lengthening, endodontic post placement, orthodontic forced eruption, core build-up and metal-ceramic crown restoration were sequentially performed to conserve the fractured tooth. Forced eruption is preferred to surgical removal of supporting alveolar bone, since forced eruption preserves the biologic width, maintains esthetics, and at the same time exposes sound tooth structure for the placement of restorative margins.

Matched MeSH terms: Dental Prosthesis Design
Periodic Assessment of Peri-implant Tissue Changes: Imperative for Implant Success

Rahman SA, Muhammad H, Haque S, Alam MK

J Contemp Dent Pract, 2019 Feb 01;20(2):173-178.
PMID: 31058631

AIM: The aim of this study was to evaluate the changes in the peri-implant hard and soft tissues and implant stability and to assess the correlation of bone loss and peri-implant probing depth with implant stability.
MATERIALS AND METHODS: Twenty-one patients with implants were included in this study and implants were assessed by resonance frequency analysis (RFA). Bone levels of the implants were assessed by measuring mesial and distal bone levels from the periapical radiograph, and soft tissue was assessed from probing depth using a periodontal probe. Implants were assessed for stability and probing depth at pre-loading, at 3 months and 6 months post-loading. RFA and probing depth were statistically compared from different time points. Correlation of probing depth and marginal bone loss with implant stability was also determined.
RESULTS: The average change in implant stability quotient (ISQ) measurements from pre-loading to 6 months post-loading was found to be statistically significant (p <0.005). The average probing depth reduced from 1.767 mm at pre-loading to 1.671 mm at post-loading 3 months, and 1.600 mm at post-loading 6 months. At 6 months of function, radiographic examination yielded 0.786 mm mesial bone loss and 0.8 mm distal bone loss. It was found to be statistically significant (p <0.005) but within an acceptable range. No significant correlation was found between implant stability and bone loss; and implant stability and probing depth.
CONCLUSION: The study revealed an increasing trend in implant stability values with the time that indicates successful osseointegration. Increasing mean values for mesial and distal bone loss were also found.
CLINICAL SIGNIFICANCE: The success of dental implants is highly dependent on the quality of bone and implant-bone interface, i.e., osseointegration. The most important factors that influence the survival rate of an implant is initial stability. The present study found the changes in the peri-implant hard and soft tissues and implant stability. This article, while being a prospective study, may show the evidence of successful osseointegration by increasing trend in implant stability (RFA) values with time which can help to the clinician in the long-term management of implants.

Matched MeSH terms: Dental Prosthesis Design
Fulltext Polymer-free drug-coated coronary stents in patients at high bleeding risk

Urban P, Meredith IT, Abizaid A, Pocock SJ, Carrié D, Naber C, et al.

N Engl J Med, 2015 Nov 19;373(21):2038-47.
PMID: 26466021 DOI: 10.1056/NEJMoa1503943

BACKGROUND: Patients at high risk for bleeding who undergo percutaneous coronary intervention (PCI) often receive bare-metal stents followed by 1 month of dual antiplatelet therapy. We studied a polymer-free and carrier-free drug-coated stent that transfers umirolimus (also known as biolimus A9), a highly lipophilic sirolimus analogue, into the vessel wall over a period of 1 month.
METHODS: In a randomized, double-blind trial, we compared the drug-coated stent with a very similar bare-metal stent in patients with a high risk of bleeding who underwent PCI. All patients received 1 month of dual antiplatelet therapy. The primary safety end point, tested for both noninferiority and superiority, was a composite of cardiac death, myocardial infarction, or stent thrombosis. The primary efficacy end point was clinically driven target-lesion revascularization.
RESULTS: We enrolled 2466 patients. At 390 days, the primary safety end point had occurred in 112 patients (9.4%) in the drug-coated-stent group and in 154 patients (12.9%) in the bare-metal-stent group (risk difference, -3.6 percentage points; 95% confidence interval [CI], -6.1 to -1.0; hazard ratio, 0.71; 95% CI, 0.56 to 0.91; P<0.001 for noninferiority and P=0.005 for superiority). During the same time period, clinically driven target-lesion revascularization was needed in 59 patients (5.1%) in the drug-coated-stent group and in 113 patients (9.8%) in the bare-metal-stent group (risk difference, -4.8 percentage points; 95% CI, -6.9 to -2.6; hazard ratio, 0.50; 95% CI, 0.37 to 0.69; P<0.001).
CONCLUSIONS: Among patients at high risk for bleeding who underwent PCI, a polymer-free umirolimus-coated stent was superior to a bare-metal stent with respect to the primary safety and efficacy end points when used with a 1-month course of dual antiplatelet therapy. (Funded by Biosensors Europe; LEADERS FREE ClinicalTrials.gov number, NCT01623180.).

Matched MeSH terms: Prosthesis Design
Polymer-based or Polymer-free Stents in Patients at High Bleeding Risk

Windecker S, Latib A, Kedhi E, Kirtane AJ, Kandzari DE, Mehran R, et al.

N Engl J Med, 2020 03 26;382(13):1208-1218.
PMID: 32050061 DOI: 10.1056/NEJMoa1910021

BACKGROUND: Polymer-free drug-coated stents provide superior clinical outcomes to bare-metal stents in patients at high bleeding risk who undergo percutaneous coronary intervention (PCI) and are treated with 1 month of dual antiplatelet therapy. Data on the use of polymer-based drug-eluting stents, as compared with polymer-free drug-coated stents, in such patients are limited.
METHODS: In an international, randomized, single-blind trial, we compared polymer-based zotarolimus-eluting stents with polymer-free umirolimus-coated stents in patients at high bleeding risk. After PCI, patients were treated with 1 month of dual antiplatelet therapy, followed by single antiplatelet therapy. The primary outcome was a safety composite of death from cardiac causes, myocardial infarction, or stent thrombosis at 1 year. The principal secondary outcome was target-lesion failure, an effectiveness composite of death from cardiac causes, target-vessel myocardial infarction, or clinically indicated target-lesion revascularization. Both outcomes were powered for noninferiority.
RESULTS: A total of 1996 patients at high bleeding risk were randomly assigned in a 1:1 ratio to receive zotarolimus-eluting stents (1003 patients) or polymer-free drug-coated stents (993 patients). At 1 year, the primary outcome was observed in 169 of 988 patients (17.1%) in the zotarolimus-eluting stent group and in 164 of 969 (16.9%) in the polymer-free drug-coated stent group (risk difference, 0.2 percentage points; upper boundary of the one-sided 97.5% confidence interval [CI], 3.5; noninferiority margin, 4.1; P = 0.01 for noninferiority). The principal secondary outcome was observed in 174 patients (17.6%) in the zotarolimus-eluting stent group and in 169 (17.4%) in the polymer-free drug-coated stent group (risk difference, 0.2 percentage points; upper boundary of the one-sided 97.5% CI, 3.5; noninferiority margin, 4.4; P = 0.007 for noninferiority).
CONCLUSIONS: Among patients at high bleeding risk who received 1 month of dual antiplatelet therapy after PCI, use of polymer-based zotarolimus-eluting stents was noninferior to use of polymer-free drug-coated stents with regard to safety and effectiveness composite outcomes. (Funded by Medtronic; ONYX ONE ClinicalTrials.gov number, NCT03344653.).

Matched MeSH terms: Prosthesis Design
Fulltext Growing endoprosthesis in management of bone tumours in Malaysia

Saravanan S, Vivek AS

Med J Malaysia, 2007 Dec;62(5):418-9.
PMID: 18705481 MyJurnal

This is to report on the use of growing endoprosthesis, also known as lengthening prosthesis in the management of four patients in the paedriatic age group in the Orthopaedic Oncolgy Unit at University Malaya Medical Centre. These are custom made prosthesis, designed and made in India based on measured roentrograms. The ages of these patients vary from 6 to 13 years old. These are cases of Osteosarcoma and Ewing's sarcoma around the knee. This is the first time these custom made prosthesis have ever been used in Malaysia. We feel that this is a feasible option for limb salvage in the treatment of primary bone tumours in growing children.

Matched MeSH terms: Prosthesis Design
Fulltext Locking compression plate: a treatment option for diaphyseal nonunion of radius or ulna

Ling HT, Kwan MK, Chua YP, Deepak AS, Ahmad TS

Med J Malaysia, 2006 Dec;61 Suppl B:8-12.
PMID: 17600986

Treatment of radius or ulna nonunion requires both osteogenic environment and mechanical stability. We would like to report three radial and six ulnar diaphyseal nonunions treated with 3.5 mm locking compression plate (LCP) fixation. To assess the effectiveness of 3.5 mm LCP in treating diaphyseal nonunion of the forearm bones, we prospectively reviewed nine patients with the mean age of 33 years with diaphyseal nonunion of the radius or ulna. All patients were treated with 3.5 mm LCP. Bone grafting was only performed for atrophic nonunion. Surgical and functional outcome were evaluated. There were three atrophic nonunion of the radius, four atrophic nonunion of the ulna and two hypertrophic nonunion of the ulna. All nonunion united successfully with satisfactory functional outcome. 3.5 mm LCP is effective in the treatment of nonunion of ulna or radius.

Matched MeSH terms: Prosthesis Design
Fulltext Size of interlocking nails used in the treatment of diaphyseal femoral fractures

Tan WJ, Kwan MK, Deepak AS, Saw A, Peng BC, Jalalullah W

Med J Malaysia, 2006 Dec;61 Suppl B:18-22.
PMID: 17600988

Fracture of the femur is most commonly treated with interlocking nailing. We conducted this study to describe and analyze the size of femoral interlocking nails used in our local population. This is a retrospective study on reamed intramedullary interlocking nailing procedures performed between 1st July 1998 and 30th June 2003. Demographic data, the diameter and length of femoral nails used were obtained from patient's medical record. A total of 267 procedures were included. The most common diameter used was 10 mm (56.9%), followed by 11 mm (27.0%) and 12 mm (13.1%). Only 2.6% of the nails were less than 10 mm in diameter. The most common nail length was 38 cm (31.1%), followed by 36 cm (24.9%) and 40 cm (19.5%). The longest nail used was 46 cm while the shortest 32 cm. The most commonly used femoral nails were of 10 mm diameter with the length ranging from 36 to 40 cm, which is smaller than those reported in the English literature. Nails with diameter smaller than 10 mm were required in 2.6% of patients.

Matched MeSH terms: Prosthesis Design
Fulltext Moulded cement-prosthesis for osteosarcoma of the proximal humerus

Pan KL, Ong GB, Potukuchi AP

Med J Malaysia, 2006 Dec;61 Suppl B:55-7.
PMID: 17600994

We report a case of an 11-year-old boy with osteosarcoma of the proximal humerus treated with wide excision and reconstruction with a cement spacer-prosthesis. After seven years of follow-up, the patient is now almost a young adult. We present his current physical and functional status, which seems to defray the initial doubts regarding long-term problems when we chose this method of reconstruction.

Matched MeSH terms: Prosthesis Design
Fulltext Tracheobronchial stenting is safe and effective in relieving upper airway obstruction

Pang YK, Liam CK, Leow CH, Shyamala P, Zal AR

Med J Malaysia, 2006 Jun;61(2):147-50.
PMID: 16898303 MyJurnal

Many studies have shown that tracheobronchial stenting is effective in relieving respiratory distress secondary to major airway obstruction due to lung or oesophageal cancer. A retrospective review on the benefits and complications of self-expandable metallic stent (SEMS) insertion through flexible bronchoscopy for the palliative treatment of upper airway obstruction in University Malaya Medical Centre was performed. Ten patients underwent this procedure. Relief of dyspnoea was immediate following stent insertion in all patients. Stent migration occurred in one patient and three patients had restenosis of the central airway. We conclude that tracheobronchial stenting via flexible bronchoscopy is feasible and safe.

Matched MeSH terms: Prosthesis Design
Fulltext Early results of Rotating Platform total knee replacement

Arif M, Makundala V, Choon DSK

Med J Malaysia, 2005 Jul;60 Suppl C:99-103.
PMID: 16381292 MyJurnal

We report on our early experiences with the Press Fit Condylar Rotating Platform (PFC-RP) total knee replacement prosthesis at University Malaya Medical Centre. This new prosthesis was introduced to Malaysia in 2001. It combines the rotating platform technology of Low Contact Stress (LCS) and the modularity of Press Fit Condylar (PFC) system. We performed 18 knee replacements using cruciate retaining prosthesis without patellar resurfacing in 10 patients and followed them up over a period of 16-month. A new operative strategy was developed to match the flexion and extension gaps. The pre- and post-operative assessments were made according to the American Knee Society Scores (AKSS). Post-operative pain relief, range of motion, knee score and functional score showed promising early results. The average knee rating improved from 28 to 91 (range 75-94). Average functional assessment improved from 26 to 82 (range 75-90). The radiographic assessments show correction of an average pre-operative varus of 140 to post-operative valgus of 50 (range 4-70). Early infection occurred in two knees. Both responded to aggressive debridement and antibiotics. Stiffness was encountered in one patient. There were no spinouts of the insert. We are satisfied that the implants are performing well at the one-year mark and will continue monitor this cohort.

Matched MeSH terms: Prosthesis Design
Factors inducing in-stent restenosis: an in-vitro model

Santin M, Morris C, Harrison M, Mikhalovska L, Lloyd AW, Mikhalovsky S

Med J Malaysia, 2004 May;59 Suppl B:93-4.
PMID: 15468834

In-stent restenosis is caused by the proliferation of the smooth muscle cells (SMCs) following a host response towards the implanted device. However, the precise biochemical and cellular mechanisms are still not completely understood. In this paper, the behaviour of SMCs has been investigated by an in vitro model where the cells were stimulated by platelet derived growth factor (PDGF) on tissue-like substrates as well as on biomaterials such as stainless steel (St) and diamond-like carbon (DLC)-coated St. The results demonstrated that SMCs have a completely different adhesion mode on St and become particularly prone to proliferation and pro-inflammatory cytokine secretion under PDGF stimulus. This would suggest that restenosis may caused by the accidental contact of the SMC with the St substrate under an inflammatory insult.

Matched MeSH terms: Prosthesis Design
From concept to patient--biomaterials solutions to medical problems

Bonfield W

Med J Malaysia, 2004 May;59 Suppl B:1.
PMID: 15468788
Matched MeSH terms: Prosthesis Design
Fulltext Early results of metal on metal articulation total hip arthroplasty in young patients

Mohamad JA, Kwan MK, Merican AM, Abbas AA, Kamari ZH, Hisa MK, et al.

Med J Malaysia, 2004 Dec;59 Suppl F:3-7.
PMID: 15941153

We report our early experience of 20 cases of metal on metal articulation total hip arthroplasty in 19 young patients. Avascular necrosis of the femoral head (63%) was the commonest diagnosis for patients undergoing this procedure, followed by osteoarthritis (21%). In general, most of the patients were young and physically active with an average age of 43.1 years (range, 25 to 58 years). The average follow-up period was 18 months (range, 7 to 46 months). The mean total Harris Hip Score preoperatively and at final follow-up was 31 points and 89 points respectively. The mean total Pain Score improved from an average of 11.5 to 41.1 points at final follow-up. Sixteen (84%) of the patients had a good to excellent hip score. There was one dislocation, which stabilized after reduction and conservative management. One case of early infection underwent a two-staged revision.

Matched MeSH terms: Prosthesis Design
Fulltext New hips for old! Lessons from the Arabian Nights

Harwant S

Med J Malaysia, 2004 Dec;59 Suppl F:2.
PMID: 15941152
Matched MeSH terms: Prosthesis Design
Cardiac valve replacement--a brief review

Lim KO

Med J Malaysia, 1977 Sep;32(1):67-70.
PMID: 609349
Matched MeSH terms: Prosthesis Design

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