MyMedR

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.

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

Five- to 12-year follow-up of a hydroxyapatite-coated, cementless total knee replacement in young, active patients

Tai CC, Cross MJ

J Bone Joint Surg Br, 2006 Sep;88(9):1158-63.

PMID: 16943464

We carried out a prospective study of 118 hydroxyapatite-coated, cementless total knee replacements in patients who were = 55 years of age and who had primary (92; 78%) or post-traumatic (26; 22%) osteoarthritis. The mean period of follow-up was 7.9 years (5 to 12.5). The Knee Society clinical scores improved from a pre-operative mean of 98 (0 to 137) to a mean of 185 (135 to 200) at five years, and 173 (137 to 200) at ten years. There were two revisions of the tibial component because of aseptic loosening, and one case of polyethylene wear requiring further surgery. There was no osteolysis or progressive radiological loosening of any other component. At 12 years, the overall rate of implant survival was 97.5% (excluding exchange of spacer) and 92.1% (including exchange of spacer). Cementless total knee replacement can achieve excellent long-term results in young, active patients with osteoarthritis. In contrast to total hip replacement, polyethylene wear, osteolysis and loosening of the prosthesis were not major problems for these patients, although it is possible that this observation could change with longer periods of follow-up.

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

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

Anatomy and Physiology of Left Ventricular Suction Induced by Rotary Blood Pumps

Salamonsen RF, Lim E, Moloney J, Lovell NH, Rosenfeldt FL

Artif Organs, 2015 Aug;39(8):681-90.

PMID: 26146861 DOI: 10.1111/aor.12550

This study in five large greyhound dogs implanted with a VentrAssist left ventricular assist device focused on identification of the precise site and physiological changes induced by or underlying the complication of left ventricular suction. Pressure sensors were placed in left and right atria, proximal and distal left ventricle, and proximal aorta while dual perivascular and tubing ultrasonic flow meters measured blood flow in the aortic root and pump outlet cannula. When suction occurred, end-systolic pressure gradients between proximal and distal regions of the left ventricle on the order of 40-160 mm Hg indicated an occlusive process of variable intensity in the distal ventricle. A variable negative flow difference between end systole and end diastole (0.5-3.4 L/min) was observed. This was presumably mediated by variable apposition of the free and septal walls of the ventricle at the pump inlet cannula orifice which lasted approximately 100 ms. This apposition, by inducing an end-systolic flow deficit, terminated the suction process by relieving the imbalance between pump requirement and delivery from the right ventricle. Immediately preceding this event, however, unnaturally low end-systolic pressures occurred in the left atrium and proximal left ventricle which in four dogs lasted for 80-120 ms. In one dog, however, this collapse progressed to a new level and remained at approximately -5 mm Hg across four heart beats at which point suction was relieved by manual reduction in pump speed. Because these pressures were associated with a pulmonary capillary wedge pressure of -5 mm Hg as well, they indicate total collapse of the entire pulmonary venous system, left atrium, and left ventricle which persisted until pump flow requirement was relieved by reducing pump speed. We suggest that this collapse caused the whole vascular region from pulmonary capillaries to distal left ventricle to behave as a Starling resistance which further reduced right ventricular output thus contributing to a major reduction in pump flow. We contend that similar complications of manual speed control also occur in the human subject and remain a major unsolved problem in the clinical management of patients implanted with rotary blood pumps.

Matched MeSH terms: Prosthesis Design

Fulltext Outcomes of placing short implants in the posterior mandible: a preliminary randomized controlled trial

Al-Hashedi AA, Taiyeb-Ali TB, Yunus N

Aust Dent J, 2016 06;61(2):208-18.

PMID: 25966305 DOI: 10.1111/adj.12337

BACKGROUND: Short dental implants can be an alternative to bone augmentation procedures at sites of reduced alveolar bone. Most studies on short implants are retrospective or multicentre reports that lack controlled and consistent comparison between different systems. This study aimed to compare clinical and radiographic outcomes of short implants in two different systems in the posterior mandible.

METHODS: Twenty patients with two adjacent missing posterior teeth were recruited. Patients were assigned equally and randomly into two groups; Bicon(®) (6 or 8 mm) and Ankylos(®) (8 mm) implants. A two-stage surgical approach and single crowns were used for implant placement and loading. Outcomes included peri-implant clinical parameters, implant stability (Periotest values; PTVs) and peri-implant bone changes, which were assessed at baseline, 2, 6 and 12 months post-loading.

RESULTS: No implant loss was encountered up to 12 months post-loading. No significant difference in the clinical or radiographic parameters was observed except for PTVs (p < 0.05) that was lower in Ankylos(®) implants.

CONCLUSIONS: The use of short dental implants was associated with excellent 12 months clinical and radiographic outcomes. Ankylos(®) and Bicon(®) implants demonstrated similar peri-implant soft tissue and alveolar bone changes. However, Ankylos(®) implants demonstrated better implant stability at all evaluation intervals.

Matched MeSH terms: Dental Prosthesis Design

Hybrid ABSORB bioresorbable vascular scaffold and drug eluting stent or hybrid BVS-DES percutaneous coronary intervention: Method and rationale for hybrid overlapping PCI

Yew KL

Int J Cardiol, 2015;186:74-6.

PMID: 25814348 DOI: 10.1016/j.ijcard.2015.02.092

Matched MeSH terms: Prosthesis Design

Transradial percutaneous coronary intervention with Stentys self-apposing stents and Stentys-Yew technique for angulated and ectatic coronary artery

Yew KL, Kang Z

Int J Cardiol, 2015 Apr 15;185:150-2.

PMID: 25795207 DOI: 10.1016/j.ijcard.2015.03.127

Matched MeSH terms: Prosthesis Design

Fulltext A novel design, analysis and 3D printing of Ti-6Al-4V alloy bio-inspired porous femoral stem

Mehboob H, Tarlochan F, Mehboob A, Chang SH, Ramesh S, Harun WSW, et al.

J Mater Sci Mater Med, 2020 Aug 20;31(9):78.

PMID: 32816091 DOI: 10.1007/s10856-020-06420-7

The current study is proposing a design envelope for porous Ti-6Al-4V alloy femoral stems to survive under fatigue loads. Numerical computational analysis of these stems with a body-centered-cube (BCC) structure is conducted in ABAQUS. Femoral stems without shell and with various outer dense shell thicknesses (0.5, 1.0, 1.5, and 2 mm) and inner cores (porosities of 90, 77, 63, 47, 30, and 18%) are analyzed. A design space (envelope) is derived by using stem stiffnesses close to that of the femur bone, maximum fatigue stresses of 0.3σys in the porous part, and endurance limits of the dense part of the stems. The Soderberg approach is successfully employed to compute the factor of safety Nf > 1.1. Fully porous stems without dense shells are concluded to fail under fatigue load. It is thus safe to use the porous stems with a shell thickness of 1.5 and 2 mm for all porosities (18-90%), 1 mm shell with 18 and 30% porosities, and 0.5 mm shell with 18% porosity. The reduction in stress shielding was achieved by 28%. Porous stems incorporated BCC structures with dense shells and beads were successfully printed.

Matched MeSH terms: Prosthesis Design

Stress distributions in maxillary central incisors restored with various types of post materials and designs

Madfa AA, Kadir MR, Kashani J, Saidin S, Sulaiman E, Marhazlinda J, et al.

Med Eng Phys, 2014 Jul;36(7):962-7.

PMID: 24834856 DOI: 10.1016/j.medengphy.2014.03.018

Different dental post designs and materials affect the stability of restoration of a tooth. This study aimed to analyse and compare the stability of two shapes of dental posts (parallel-sided and tapered) made of five different materials (titanium, zirconia, carbon fibre and glass fibre) by investigating their stress transfer through the finite element (FE) method. Ten three-dimensional (3D) FE models of a maxillary central incisor restored with two different designs and five different materials were constructed. An oblique loading of 100 N was applied to each 3D model. Analyses along the centre of the post, the crown-cement/core and the post-cement/dentine interfaces were computed, and the means were calculated. One-way ANOVAs followed by post hoc tests were used to evaluate the effectiveness of the post materials and designs (p=0.05). For post designs, the tapered posts introduced significantly higher stress compared with the parallel-sided post (p<0.05), especially along the centre of the post. Of the materials, the highest level of stress was found for stainless steel, followed by zirconia, titanium, glass fibre and carbon fibre posts (p<0.05). The carbon and glass fibre posts reduced the stress distribution at the middle and apical part of the posts compared with the stainless steel, zirconia and titanium posts. The opposite results were observed at the crown-cement/core interface.

Matched MeSH terms: Dental Prosthesis Design

Contour analysis of an implant--soft tissue interface

Chai WL, Moharamzadeh K, van Noort R, Emanuelsson L, Palmquist A, Brook IM

J Periodontal Res, 2013 Oct;48(5):663-70.

PMID: 23442017 DOI: 10.1111/jre.12062

Studies of peri-implant soft tissue on in vivo models are commonly based on histological sections prepared using undecalcified or 'fracture' techniques. These techniques require the cutting or removal of implant during the specimen preparation process. The aim of this study is to explore a new impression technique that does not require any cutting or removal of implant for contour analysis of soft tissue around four types of titanium (Ti) surface roughness using an in vitro three-dimensional oral mucosal model (3D OMM).

Matched MeSH terms: Dental Prosthesis Design*

Mitral valve repair for congenital mitral valve disease: impact of the use of a biodegradable annuloplasty ring

Yakub MA, Sivalingam S, Dillon J, Matsuhama M, Latiff HA, Ramli MF

Ann Thorac Surg, 2015 Mar;99(3):884-90; discussion 890.

PMID: 25579160 DOI: 10.1016/j.athoracsur.2014.09.016

This study compares the midterm results of mitral valve repair using the biodegradable ring versus repair with non-ring annuloplasty techniques for congenital mitral valve disease in young children where it was not possible to use standard commercial rings.

Matched MeSH terms: Prosthesis Design

Interface stress in socket/residual limb with transtibial prosthetic suspension systems during locomotion on slopes and stairs

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

Am J Phys Med Rehabil, 2015 Jan;94(1):1-10.

PMID: 24919079 DOI: 10.1097/PHM.0000000000000134

This study aimed to compare the effects of different suspension methods on the interface stress inside the prosthetic sockets of transtibial amputees when negotiating ramps and stairs.

Matched MeSH terms: Prosthesis Design

Fulltext Interface pressure in transtibial socket during ascent and descent on stairs and its effect on patient satisfaction

Ali S, Abu Osman NA, Eshraghi A, Gholizadeh H, Abd Razak NA, Wan Abas WA

Clin Biomech (Bristol, Avon), 2013 Nov-Dec;28(9-10):994-9.

PMID: 24161521 DOI: 10.1016/j.clinbiomech.2013.09.004

Transtibial amputees encounter stairs and steps during their daily activities. The excessive pressure between residual limb/socket may reduce the walking capability of transtibial prosthetic users during ascent and descent on stairs. The purposes of the research were to evaluate the interface pressure between Dermo (shuttle lock) and Seal-In X5 (prosthetic valve) interface systems during stair ascent and descent, and to determine their satisfaction effects on users.

Matched MeSH terms: Prosthesis Design

Design of new generation femoral prostheses using functionally graded materials: a finite element analysis

Oshkour AA, Abu Osman NA, Yau YH, Tarlochan F, Abas WA

Proc Inst Mech Eng H, 2013 Jan;227(1):3-17.

PMID: 23516951

This study aimed to develop a three-dimensional finite element model of a functionally graded femoral prosthesis. The model consisted of a femoral prosthesis created from functionally graded materials (FGMs), cement, and femur. The hip prosthesis was composed of FGMs made of titanium alloy, chrome-cobalt, and hydroxyapatite at volume fraction gradient exponents of 0, 1, and 5, respectively. The stress was measured on the femoral prosthesis, cement, and femur. Stress on the neck of the femoral prosthesis was not sensitive to the properties of the constituent material. However, stress on the stem and cement decreased proportionally as the volume fraction gradient exponent of the FGM increased. Meanwhile, stress became uniform on the cement mantle layer. In addition, stress on the femur in the proximal part increased and a high surface area of the femoral part was involved in absorbing the stress. As such, the stress-shielding area decreased. The results obtained in this study are significant in the design and longevity of new prosthetic devices because FGMs offer the potential to achieve stress distribution that more closely resembles that of the natural bone in the femur.

Matched MeSH terms: Prosthesis Design

Pistoning assessment in lower limb prosthetic sockets

Eshraghi A, Osman NA, Gholizadeh H, Karimi M, Ali S

Prosthet Orthot Int, 2012 Mar;36(1):15-24.

PMID: 22269941 DOI: 10.1177/0309364611431625

One of the main indicators of the suspension system efficiency in lower limb prostheses is vertical displacement or pistoning within the socket. Decreasing pistoning and introducing an effective system for evaluating pistoning could contribute to the amputees' rehabilitation process.

Matched MeSH terms: Prosthesis Design

Fulltext Fixed rehabilitation of patient with aggressive periodontitis using zygoma implants

Rajan G, Baig MR, Nesan J, Subramanian J

Indian J Dent Res, 2010 Jan-Mar;21(1):125-8.

PMID: 20427922 DOI: 10.4103/0970-9290.62801

Treatment of patients with aggressive periodontitis has always been a challenge to the clinician. Both young and old are known to be affected by this progressive destructive condition of the supporting dental structures. Although dental implants have been offered as a viable treatment alternative for such patients, additional procedures (like bone grafting) and delayed protocols have limited their usage. This case report describes the treatment of a young patient with aggressive periodontitis using a graftless implant solution. Zygoma implants in conjunction with conventional implants were used with immediate loading.

Matched MeSH terms: Dental Prosthesis Design

Comparison of the load at fracture of Turkom-Cera to Procera AllCeram and In-Ceram all-ceramic restorations

AL-Makramani BM, Razak AA, Abu-Hassan MI

J Prosthodont, 2009 Aug;18(6):484-8.

PMID: 19694015

PURPOSE: This study investigated the occlusal fracture resistance of Turkom-Cerafused alumina compared to Procera AllCeram and In-Ceram all-ceramic restorations.

MATERIALS AND METHODS: Sixmaster dies were duplicated from the prepared maxillary first premolar tooth using nonprecious metal alloy (Wiron 99). Ten copings of 0.6 mm thickness were fabricated from each type of ceramic, for a total of thirty copings. Two master dies were used for each group, and each of them was used to lute five copings. All groups were cemented with resin luting cement Panavia F according to manufacturer's instructions and received a static load of 5 kg during cementation. After 24 hours of distilled water storage at 37 degrees C, the copings were vertically compressed using a universal testing machine at a crosshead speed of 1 mm/min.

RESULTS: The results of the present study showed the following mean loads at fracture: Turkom-Cera (2184 +/- 164 N), In-Ceram (2042 +/- 200 N), and Procera AllCeram (1954 +/- 211 N). ANOVA and Scheffe's post hoc test showed that the mean load at fracture of Turkom-Cera was significantly different from Procera AllCeram (p < 0.05). Scheffe's post hoc test showed no significant difference between the mean load at fracture of Turkom-Cera and In-Ceram or between the mean load at fracture of In-Ceram and Procera AllCeram.

CONCLUSION: Because Turkom-Cera demonstrated equal to or higher loads at fracture than currently accepted all-ceramic materials, it would seem to be acceptable for fabrication of anterior and posterior ceramic crowns.

Matched MeSH terms: Dental 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 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

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