Browsing by Author "Haleem, Amgad"

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Laser microgrooving and nanofiber membrane application for total knee replacement implants using a caprine model
(Amer Soc Mechanical Engineers, 2021-01-01) Khandaker, Morshed; Nikfarjam, Sadegh; Kari, Karim; Kalay, Onur Can; Karpat, Fatih; Progri, Helga; Bhuiyan, Ariful; Clary, Erik; Haleem, Amgad; Amer Soc Mech Engineers; KARPAT, FATİH; Kalay, Onur Can; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü; 0000-0001-8474-7328; A-5259-2018; GDQ-4936-2022
Aseptic loosening is a well-recognized phenomenon in cementless total knee replacement (TKR) and often carries severe consequences for the patient. We recently developed and tested in vitro a novel strategy for enhancing osseointegration and acute mechanical stability of orthopedic implants that employ laser-induced microgroove (LIM) and nanofiber membrane (NFM) applications at the bone-implant interface. We report herein investigation of the approach with results from a pilot study employing three skeletally mature female Spanish cross goats (similar to 4y 35-45kg) receiving cementless TKR with a commercially available implant system (Biomedrix (R) Canine Total Knee). Pre-operative radiographs were taken to ensure limb normality and to select the appropriately sized implants for each goat. With the animal under general anesthesia and the limb properly prepped for aseptic surgery, the stifle was approached, and osteotomies of the proximal tibia and distal femur performed in preparation for implantation of the tibial (TT) and femoral (FT) trays. For one goat, the arthroplasty implant surfaces were unaltered from the manufacturer 's mirrorpolished (MP) condition. For the other two goats, the TT bonecontact surface was laser-micro grooved (150 mu m depth, 200 mu m width, 200 pm spacing) prior to sterilization and then implanted with (LIM/NFM) or without (LIM) an intermediate (surfaceapplied) polycaprolactone (PCL) nanofiber mesh (50x50mm, electrospun, aligned, unidirectional, 10 mu m thickness). Following surgery, animals received appropriate analgesic therapy and rehabilitative care to maximize animal comfort, function, and quality of life while limiting the risk of major complications. Post-operative monitoring included assessment of mentation, vital signs, pain level, digestive function (weight, appetite, rumen contractions, feed intake, fecal output), and limb status (usage, range of motion, muscular volume). By the study's end (12 wks), all animals had recovered a pre-surgery range of motion in the operated knee and exhibited typical bony changes on radiographic follow-up. At necropsy following humane euthanasia, no gross instability of TKR components was observed. Histomorphomefric analysis of explanted bone-TT constructs showed the increased new bone surface area in the LIM-NFM sample (0.49 mm(2)) compared with the MP sample (0.03 mm(2)), suggesting that microgrooves and/or PCL nanofiber coating may improve the clinical performance of the implant. A finite element analysis (FEA) model was developed to explore the impact of surface micro grooving to the mechanical stimuli at the bone-implant interface to supplement the in vivo studies. The three-dimensional geometry of the tibia was scanned using computed tomography and imported into a proprietary (MIMICS (R)) software to construct the solid models for finite element micro-strain analyses.
Laser-induced microgrooves improve the mechanical responses of cemented implant systems
(MDPI, 2020-04-27) Khandaker, Morshed; Moussa, Abdellah Ait; Sama, Desmond Nuyebga; Safavinia, Fereshteh; Hazra, Susmita; Kalay, Onur Can; Karpat, Fatih; Clary, Erik; Haleem, Amgad; Kalay, Onur Can; KARPAT, FATİH; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; 0000-0001-8643-6910; 0000-0001-8474-7328; GDQ-4936-2022 ; A-5259-2018
The impact of a laser-induced microgroove (LIM) architecture on mechanical responses of two cemented implant systems was evaluated. One system consisted of two aluminum alloy rods bonded end-to-end by polymethylmethacrylate cement. The second system consisted of a custom-made, aluminum tibial tray (TT) cemented in an artificial canine tibia. Control specimens for each system were polished smooth at the cement interface. For LIM samples in the rod system, microgrooves were engraved (100 mu m depth, 200 mu m width, 500 mu m spacing) on the apposing surface of one of the two rods. For TT system testing, LIM engraving (100 mu m spacing) was confined to the underside and keel of the tray. Morphological analysis of processed implant surfaces revealed success in laser microgrooving procedures. For cemented rods tested under static tension, load to failure was greater for LIM samples (279.0 +/- 14.9 N vs. 126.5 +/- 4.5 N). Neither non-grooved nor grooved TT samples failed under cyclic compression testing (100,000 cycles at 1 Hz). Compared with control specimens, LIM TT constructs exhibited higher load to failure under static compression and higher strain at the bone interface under cyclic compression. Laser-induced microgrooving has the potential to improve the performance of cemented orthopedic implants.
The effect of micro grooving on goat total knee replacement: A finite element study
(Amer Soc Mechanical Engineers, 2020-01-01) Khandaker, Morshed; Haleem, Amgad; Williams, Wendy; Boyce, Kari E.; Clary, Erik; Agrawal, Kshitijkumar; Kalay, Onur Can; Karpat, Fatih; KARPAT, FATİH; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; 0000-0001-5985-7402; 0000-0001-8643-6910; 0000-0001-8474-7328; A-5259-2018
A method to improve the mechanical fixation of a total knee replacement (TKR) implant is clinically important and is the purpose of this study. More than one million joint replacement procedures are performed in people each year in the United States, and experts predict the number to increase six-fold by the year 2030. Whether cemented or uncemented, joint prostheses may destabilize over time and necessitate revision. Approximately 40,000 hip arthroplasty surgeries have to be revised each year and the rate is expected to increase by approximately 140% (and by 600% for total knee replacement) over the next 25 years. In veterinary surgery, joint replacement has a long history and the phenomenon of surgical revision is also well recognized. For the betterment of both people and animals, improving the longevity of arthroplasty devices is of the utmost clinical importance, and towards that end, several strategies are under investigation. One approach that we explore in the present research is to improve the biomechanical performance of cemented implant systems by altering the implant surface architecture in a way that facilitates its cement bonding capacity. Beginning with the Charnley system, early femoral stems were polished smooth, but a number of subsequent designs have featured a roughened surface-created with bead or grit blasting-to improve cement bonding. Failure at the implant-cement interface remains an issue with these newer designs, leading us to explore in this present research an alternate, novel approach to surface alteration- specifically, laser microgrooving. This study used various microgrooves architectures that is feasible using a laser micromachining process on a tibia tray (TT) for the goat TKR. Developing the laser microgrooving (LM) procedure, we hypothesized feasibility in producing parallel microgrooves of precise dimensions and spacing on both flat and round metallic surfaces. We further hypothesized that laser microgrooving would increase surface area and roughness of the cement interface of test metallic implants and that such would translate into an improved acute mechanical performance as assessed in vitro under both static and cyclic loads. The objective was to develop a computational model to determine the effect of LIM on the tibial tray to the mechanical stimuli distributions from implant to bone using the finite element method. This study designed goat TT 3D solid model from a computer topography (CT) images, out of which three different laser microgrooves were engraved on TT sample by varying depth, height and space between two adjacent grooves. The simulation test results concluded that microgrooves acchitecures positively influence microstrain behavior around the implant/bone interfaces. There is a higher amount of strain observed for microgroove implant/bone samples compared to non-groove implant/bone samples. Thus, the laser-induced microgrooves have the potential to be used clinically in TKR components.