The Experts below are selected from a list of 582 Experts worldwide ranked by ideXlab platform

Michael A. Mont - One of the best experts on this subject based on the ideXlab platform.

  • Excellent Survivorship With the Use of Proximally Coated Tapered Cementless Stems for Total Hip Arthroplasty in
    2016
    Co-Authors: Alex D. Stroh, Michael G. Zywiel, Aaron J. Johnson, Michael A. Mont
    Abstract:

    The use of total hip arthroplasty (THA) continues to grow partially because of the increasing life expectancy of the American population. Whether to use cemented or cementless femoral fixation options in older patients is often debated. The purpose of the present study was to compare the clinical and radiographic outcomes after cementless THA in patients 80 years to younger patients. Clinical and radiographic data were gathered on 33 patients (35 hips) all 80 years or older who had undergone proximally coated cementless total hip arthroplasties. Outcomes were compared with a matching group for age, body mass index, and diagnosis, who had undergone the same procedure by the same surgeon at a similar time. Harris hip scores were evaluated pre- and postoperatively, and radiographs were reviewed for evaluation of fixation and stability. At a mean follow-up of 4 years, 97 % of the hips (34 of 35) remained unrevised and the mean Harris hip score had improved by 39 points to 83 points (range, 26-100 points). On radiographic evaluation, 91 % were found to have full Bony Ingrowth, with 1 hip having osteolysis of the proximal femur. Mortality was 23 % at 86 months. Except for mortality, the outcomes and complica-tion rates were similar to the younger group except that the matching group had higher final postoperative Harris hip scores. Proximally coated tapered cementless THA is a safe and efficacious method for providing good clinical outcomes with low revision rates in patients 80 years of age or older

  • Excellent Survivorship With the Use of Proximally Coated Tapered Cementless Stems for Total Hip Arthroplasty in Octogenarians
    'SAGE Publications', 2011
    Co-Authors: Michael G. Zywiel, Aaron J. Johnson, Michael A. Mont
    Abstract:

    The use of total hip arthroplasty (THA) continues to grow partially because of the increasing life expectancy of the American population. Whether to use cemented or cementless femoral fixation options in older patients is often debated. The purpose of the present study was to compare the clinical and radiographic outcomes after cementless THA in patients ≥80 years to younger patients. Clinical and radiographic data were gathered on 33 patients (35 hips) all 80 years or older who had undergone proximally coated cementless total hip arthroplasties. Outcomes were compared with a matching group for age, body mass index, and diagnosis, who had undergone the same procedure by the same surgeon at a similar time. Harris hip scores were evaluated pre- and postoperatively, and radiographs were reviewed for evaluation of fixation and stability. At a mean follow-up of 4 years, 97% of the hips (34 of 35) remained unrevised and the mean Harris hip score had improved by 39 points to 83 points (range, 26-100 points). On radiographic evaluation, 91% were found to have full Bony Ingrowth, with 1 hip having osteolysis of the proximal femur. Mortality was 23% at 86 months. Except for mortality, the outcomes and complication rates were similar to the younger group except that the matching group had higher final postoperative Harris hip scores. Proximally coated tapered cementless THA is a safe and efficacious method for providing good clinical outcomes with low revision rates in patients 80 years of age or older

  • clinical experience with a proximally porous coated second generation cementless total hip prosthesis minimum 5 year follow up
    Journal of Arthroplasty, 1999
    Co-Authors: Michael A. Mont, Taek Rim Yoon, Kenneth A Krackow, David S Hungerford
    Abstract:

    This study reports the minimum 5-year follow-up of our experience with the Porous-Coated Anatomic E (PCA-E) series femoral stem and the modular acetabular cup. A total of 115 consecutive total hip replacements using PCA-E series (Howmedica, Rutherford, NJ) were performed in 108 patients. Six patients whose hips were performing well clinically died before 5-year follow-up and were excluded from the final evaluation. The remaining 109 hips (102 patients) were assessed at a mean follow-up of 72 months (range, 60-84 months). The hip diagnoses were osteoarthritis in 73, osteonecrosis in 31, rheumatoid arthritis in 2, and hip dysplasia in 3. The mean age was 56 years (range, 24-83 years). Three hips were revised: 1 because of late hematogenous infection, 1 because of aseptic loosening of the femoral component, and 1 because of postoperative loosening of an acetabular component. The Harris hip scores improved from a mean of 50 points (range, 20-66 points) preoperatively to a mean of 92 points (range, 64-100 points) at final follow-up. The score differed in each Charnley functional class, with a mean of 93 points (range, 72-100 points) in 57 hips of class A (no other joint involvement); 90 points (range, 58-100 points) in 26 hips of class B (opposite hip involvement); and 85 points (range, 37-100 points) in 26 hips of class C (multiple joint involvement or severe systemic disease). Out of 106 hips that had a full radiographic evaluation performed, 103 femoral components revealed stable Bony Ingrowth, 2 revealed stable fibrous Ingrowth, and 1 showed migration with progressive loosening. This patient with radiographic loosening has minimal symptoms and has not required or been offered further surgery (Harris hip score of 86 points). The low aseptic loosening rate (2%) at minimum 5-year follow-up compares favorably with any cemented or cementless series. The osteolysis that was seen was focal and localized. The short follow-up does not allow determination of progression. There were no cases of distal osteolysis. We attribute the improved results from reported first-generation experience to multiple factors, including increased number of sizes (9 vs 6), increased proportional metaphyseal size, improved polyethylene manufacture (ram extruded vs machined), improved acetabular locking mechanism, and change to 26-mm from 32-mm femoral heads.

Graham A Gie - One of the best experts on this subject based on the ideXlab platform.

  • posterior longitudinal split osteotomy for femoral component extraction in revision total hip arthroplasty
    Journal of Arthroplasty, 2008
    Co-Authors: Adrian John Bauze, John Charity, Eleftherios Tsiridis, John A Timperley, Graham A Gie
    Abstract:

    We present a technique of single posterior longitudinal split osteotomy. This technique allows the expansion of the proximal femur and easier extraction of uncemented femoral components. Since 1998 we have performed this osteotomy in 12 revision total hip arthroplasties in 11 patients who had either stable fibrous Ingrowth or a small amount of Bony Ingrowth. All were revised to a cemented Exeter stem (Stryker Benoist Gerard, Caen, France). No patient required conversion from a longitudinal split to an extended trochanteric osteotomy. At mean follow-up of 48 months, there were significant improvements in both pain and function. There were no complications due to this technique. Mean in-cement taper engagement (subsidence) was 1.1 mm (range, 0-2 mm). Femoral impaction grafting did not adversely affect the cement mantle or increase in-cement taper engagement. With appropriate patient selection, this is a simple, reliable, and extensile technique to assist in the extraction of uncemented ongrowth femoral components whether hydroxyapatite-coated or not.

B Tomeno - One of the best experts on this subject based on the ideXlab platform.

  • comparative radiographic analysis of bone Ingrowth on the guepar knee prosthesis and on a massive prosthesis with an hydroxyapatite collar
    Orthopaedic Proceedings, 2018
    Co-Authors: P Laudrin, A Babinet, Philippe Anract, B Tomeno
    Abstract:

    Purpose: Hinged knee prostheses are mainly used for reconstruction after major tumour resection. Aseptic loosening is the main problem with these implants. One of the solutions proposed to reduce the rate of loosening is to add a hydroxyapatite collar on the shaft stems. This work was conducted to study bone Ingrowth with a new hinged implant with a hydroxyapatite collar at the junction between the zone of resection and the shaft.Material and methods: Twenty-nine massive prostheses with a hydroxyapatite collar were implanted between 1998 and 2001. Nine patients were excluded from the analysis because follow-up was less than two years. This retrospective analysis thus compared twenty massive prostheses with twenty matched hinged GUEPAR prostheses without a collar. Bony Ingrowth was measured on plain x-rays (two orthogonal views) at 6, 12, 24, and 36 months. Filling of the gap between the bone and the implant was also assessed. Signs of loosening were noted.Results: Mean Bony Ingrowth in implants with a hyd...

  • comparative radiographic analysis of bone Ingrowth on the guepar knee prosthesis and on a massive prosthesis with an hydroxyapatite collar
    Journal of Bone and Joint Surgery-british Volume, 2005
    Co-Authors: P Laudrin, A Babinet, Philippe Anract, B Tomeno
    Abstract:

    Purpose: Hinged knee prostheses are mainly used for reconstruction after major tumour resection. Aseptic loosening is the main problem with these implants. One of the solutions proposed to reduce the rate of loosening is to add a hydroxyapatite collar on the shaft stems. This work was conducted to study bone Ingrowth with a new hinged implant with a hydroxyapatite collar at the junction between the zone of resection and the shaft. Material and methods: Twenty-nine massive prostheses with a hydroxyapatite collar were implanted between 1998 and 2001. Nine patients were excluded from the analysis because follow-up was less than two years. This retrospective analysis thus compared twenty massive prostheses with twenty matched hinged GUEPAR prostheses without a collar. Bony Ingrowth was measured on plain x-rays (two orthogonal views) at 6, 12, 24, and 36 months. Filling of the gap between the bone and the implant was also assessed. Signs of loosening were noted. Results: Mean Bony Ingrowth in implants with a hydroxyapatite collar was 6.58 mm at 6 months 9.84 mm at 12 months, 12.3 mm at 24 months and 13.25 mm at 36 months. Mean Bony Ingrowth in the implants without a hydroxyapatite collar was 1.65 mm at 6 months, 3.31 mm at 12 months, 4.8 mm at 24 months and 4.35 mm at 36 months. In the implants with a collar, gap filling was partial in five cases and total in 15. In implants without a collar, there was no gap filling in eight cases, partial filling in two cases and total filling in fifteen cases. Discussion: Prostheses with a hydroxyapatite collar enable better radiological Bony Ingrowth than observed in implants without a hydroxyapatite collar. Gap filling is better for prostheses with a collar. There was no case of loosening at last follow-up for implants with a hydroxyapatite collar. Conclusion: In light of these results, shaft anchorage appears to be better with implants with a hydrosyapatite collar. Confirmation of improvement in clinical outcome and lower rate of aseptic loosening will require longer follow-up.

Frederick C Eichmiller - One of the best experts on this subject based on the ideXlab platform.

  • strong and macroporous calcium phosphate cement effects of porosity and fiber reinforcement on mechanical properties
    Journal of Biomedical Materials Research, 2001
    Co-Authors: Hockin H K Xu, Janet B Quinn, Shozo Takagi, Laurence C. Chow, Frederick C Eichmiller
    Abstract:

    Because of its excellent osteoconductivity and bone-replacement capability, self-setting calcium phosphate cement (CPC) has been used in a number of clinical procedures. For more rapid resorption and concomitant osseointegration, methods were desired to build macropores into CPC; however, this decreased its mechanical properties. The aims of this study, therefore, were to use fibers to strengthen macroporous CPC and to investigate the effects of the pore volume fraction on its mechanical properties. Water-soluble mannitol crystals were incorporated into CPC paste; the set CPC was then immersed in water to dissolve mannitol, producing macropores. Mannitol/(mannitol + CPC powder) mass fractions of 0, 10, 20, 30, and 40% were used. An aramid fiber volume fraction of 6% was incorporated into the CPC–mannitol specimens, which were set in 3 mm × 4 mm × 25 mm molds and then fractured in three-point flexure to measure the strength, work of fracture, and modulus. The dissolution of mannitol created well-formed macropores, with CPC at 40% mannitol having a total porosity of a 70.8% volume fraction. Increasing the mannitol content significantly decreased the properties of CPC without fibers (analysis of variance; p < 0.001). The strength (mean ± standard deviation; n = 6) of CPC at 0% mannitol was 15.0 ± 1.8 MPa; at 40% mannitol, it decreased to 1.4 ± 0.4 MPa. Fiber reinforcement improved the properties, with the strength increasing threefold at 0% mannitol, sevenfold at 30% mannitol, and nearly fourfold at 40% mannitol. The work of fracture increased by 2 orders of magnitude, but the modulus was not changed as a result of fiber reinforcement. A scanning electron microscopy examination of specimens indicated crack deflection and bridging by fibers, matrix multiple cracking, and frictional pullout of fibers as the reinforcement mechanisms. Macroporous CPCs were substantially strengthened and toughened via fiber reinforcement. This may help extend the use of CPCs with macropores for Bony Ingrowth to the repair of larger defects in stress-bearing locations. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res 57: 457–466, 2001

  • strong and macroporous calcium phosphate cement effects of porosity and fiber reinforcement on mechanical properties
    Journal of Biomedical Materials Research, 2001
    Co-Authors: Janet B Quinn, Shozo Takagi, Laurence C. Chow, Frederick C Eichmiller
    Abstract:

    Because of its excellent osteoconductivity and bone-replacement capability, self-setting calcium phosphate cement (CPC) has been used in a number of clinical procedures. For more rapid resorption and concomitant osseointegration, methods were desired to build macropores into CPC; however, this decreased its mechanical properties. The aims of this study, therefore, were to use fibers to strengthen macroporous CPC and to investigate the effects of the pore volume fraction on its mechanical properties. Water-soluble mannitol crystals were incorporated into CPC paste; the set CPC was then immersed in water to dissolve mannitol, producing macropores. Mannitol/(mannitol + CPC powder) mass fractions of 0, 10, 20, 30, and 40% were used. An aramid fiber volume fraction of 6% was incorporated into the CPC-mannitol specimens, which were set in 3 mm x 4 mm x 25 mm molds and then fractured in three-point flexure to measure the strength, work of fracture, and modulus. The dissolution of mannitol created well-formed macropores, with CPC at 40% mannitol having a total porosity of a 70.8% volume fraction. Increasing the mannitol content significantly decreased the properties of CPC without fibers (analysis of variance; p < 0.001). The strength (mean +/- standard deviation; n = 6) of CPC at 0% mannitol was 15.0 +/- 1.8 MPa; at 40% mannitol, it decreased to 1.4 +/- 0.4 MPa. Fiber reinforcement improved the properties, with the strength increasing threefold at 0% mannitol, sevenfold at 30% mannitol, and nearly fourfold at 40% mannitol. The work of fracture increased by 2 orders of magnitude, but the modulus was not changed as a result of fiber reinforcement. A scanning electron microscopy examination of specimens indicated crack deflection and bridging by fibers, matrix multiple cracking, and frictional pullout of fibers as the reinforcement mechanisms. Macroporous CPCs were substantially strengthened and toughened via fiber reinforcement. This may help extend the use of CPCs with macropores for Bony Ingrowth to the repair of larger defects in stress-bearing locations.

Christian M Puttlitz - One of the best experts on this subject based on the ideXlab platform.

  • Bony Ingrowth potential of 3d printed porous titanium alloy a direct comparison of interbody cage materials in an in vivo ovine lumbar fusion model
    The Spine Journal, 2018
    Co-Authors: Kirk C Mcgilvray, Howard B Seim, Jeremiah T Easley, Daniel P Regan, Sigurd Berven, Wellington K Hsu, Thomas E Mroz, Christian M Puttlitz
    Abstract:

    Abstract Background Context There is significant variability in the materials commonly used for interbody cages in spine surgery. It is theorized that three-dimensional (3D)-printed interbody cages using porous titanium material can provide more consistent bone Ingrowth and biological fixation. Purpose The purpose of this study was to provide an evidence-based approach to decision-making regarding interbody materials for spinal fusion. Study Design A comparative animal study was performed. Methods A skeletally mature ovine lumbar fusion model was used for this study. Interbody fusions were performed at L2–L3 and L4–L5 in 27 mature sheep using three different interbody cages (ie, polyetheretherketone [PEEK], plasma sprayed porous titanium-coated PEEK [PSP], and 3D-printed porous titanium alloy cage [PTA]). Non-destructive kinematic testing was performed in the three primary directions of motion. The specimens were then analyzed using micro-computed tomography (µ-CT); quantitative measures of the Bony fusion were performed. Histomorphometric analyses were also performed in the sagittal plane through the interbody device. Outcome parameters were compared between cage designs and time points. Results Flexion-extension range of motion (ROM) was statistically reduced for the PTA group compared with the PEEK cages at 16 weeks (p-value=.02). Only the PTA cages demonstrated a statistically significant decrease in ROM and increase in stiffness across all three loading directions between the 8-week and 16-week sacrifice time points (p-value≤.01). Micro-CT data demonstrated significantly greater total bone volume within the graft window for the PTA cages at both 8 weeks and 16 weeks compared with the PEEK cages (p-value Conclusions A direct comparison of interbody implants demonstrates significant and measurable differences in biomechanical, µ-CT, and histologic performance in an ovine model. The 3D-printed porous titanium interbody cage resulted in statistically significant reductions in ROM, increases in the bone Ingrowth profile, as well as average construct stiffness compared with PEEK and PSP.

  • Evaluation of a polyetheretherketone (PEEK) titanium composite interbody spacer in an ovine lumbar interbody fusion model: biomechanical, microcomputed tomographic, and histologic analyses
    Spine Journal, 2017
    Co-Authors: Kirk C Mcgilvray, Nianli Zhang, Raymond J. Linovitz, Jeremiah Easley, Erik I. Waldorff, Howard B Seim, J.t. Ryaby, Christian M Puttlitz
    Abstract:

    Background Context The most commonly used materials used for interbody cages are titanium metal and polymer polyetheretherketone (PEEK). Both of these materials have demonstrated good biocompatibility. A major disadvantage associated with solid titanium cages is their radiopacity, limiting the postoperative monitoring of spinal fusion via standard imaging modalities. However, PEEK is radiolucent, allowing for a temporal assessment of the fusion mass by clinicians. On the other hand, PEEK is hydrophobic, which can limit Bony Ingrowth. Although both PEEK and titanium have demonstrated clinical success in obtaining a solid spinal fusion, innovations are being developed to improve fusion rates and to create stronger constructs using hybrid additive manufacturing approaches by incorporating both materials into a single interbody device. Purpose The purpose of this study was to examine the interbody fusion characteristic of a PEEK Titanium Composite (PTC) cage for use in lumbar fusion. Study Design/Setting Thirty-four mature female sheep underwent two-level (L2–L3and L4–L5) interbody fusion using either a PEEK or a PTC cage (one of each per animal). Animals were sacrificed at 0, 8, 12, and 18 weeks post surgery. Materials and Methods Post sacrifice, each surgically treated functional spinal unit underwent non-destructive kinematic testing, microcomputed tomography scanning, and histomorphometric analyses. Results Relative to the standard PEEK cages, the PTC constructs demonstrated significant reductions in ranges of motion and a significant increase in stiffness. These biomechanical findings were reinforced by the presence of significantly more bone at the fusion site as well as Ingrowth into the porous end plates. Conclusions Overall, the results indicate that PTC interbody devices could potentially lead to a more robust intervertebral fusion relative to a standard PEEK device in a clinical setting.