25 yrs male, with supracondylar humrus fracture, treated with reconstruction plate and lag screw
Friday, February 20, 2009
Wednesday, February 18, 2009
EXCHANGE NAILING OR PLATE FIXATION?????
Exchange nailing or plate fixation
orthopedic Trauma Directions 2007; 03; 11-21
Summary
Evidence from nine case series suggests rates of solid union may be lower and the complication frequency higher for exchange nailing of femoral shaft nonunions than with plate fixation. However, no comparative study was found to evaluate the efficacy and safety of these procedures and there were more series describing exchange nailing than plate fixation. Methodologically rigorous comparative studies with larger populations are necessary to establish the long term safety and efficacy of these two operative treatments and to evaluate the superiority of one treatment over another.
Studies for this case
Study 1
Banaszkiewicz PA, Sabboubeh A, McLeod I, et al (2003)Femoral exchange nailing for aseptic non-union: not the end to all problemsInjury; 34(5):349–356.
Study 2
Choi YS, Kim KS (2005)Plate augmentation leaving the nail in situ and bone grafting for non-union of femoral shaft fractures.Int Orthop; 29(5):287–290.
Study 3
Finkemeier CG, Chapman MW (2002)Treatment of femoral diaphyseal nonunions.Clin Orthop Relat Res; (398):223–234.
Study 4
Wu CC, Chen WJ (2002)Exchange nailing for aseptic nonunion of the femoral shaft.Int Orthop; 26(2):80–84.
Study 5
Bellabarba C, Ricci WM, Bolhofner BR (2001)Results of indirect reduction and plating of femoral shaft nonunions after intramedullary nailing.Journal of Orthopaedic Trauma; 15(4):254–263.
Study 6
Hak DJ, Lee SS, Goulet JA, et al (2000)Success of exchange reamed intramedullary nailing for femoral shaft nonunion or delayed union.J Orthop Trauma; 14(3):178–182.
Study 7
Ueng SW, Chao EK, Lee SS, et al (1997)Augmentative plate fixation for the management of femoral nonunion after intramedullary nailing.J Trauma; 43(4):640–644.
Study 8
Weresh MJ, Hakanson R, Stover MD, et al (2000)Failure of exchange reamed intramedullary nails for ununited femoral shaft fracturesJ Orthop Trauma; 14(5):335–338.
Study 9
Wu CC, Chen WJ (1997)Treatment of femoral shaft aseptic nonunions: comparison between closed and open bone-grafting techniquesJ Trauma; 43(1):112–116.
Sampling
A MEDLINE search was conducted for studies published between 1997 and 2006 comparing exchange nailing and plate fixation for treatment of femoral shaft nonunions. No comparative studies were found. Studies were excluded if there were fewer than five patients in any treatment group, if femoral nailing was not the initial treatment for the fracture or if outcomes for nonunion treatment were not separable. Studies were also excluded if there was loss of length of >1.5 cm or 1-stage femoral lengthening was done as part of the treatment. If multiple reports of the same study were found, the primary study report was included. Of 16 case-series identified, 9 remained after these exclusions and are summarized.
Objective
To critically summarize the outcomes and complications for exchange nailing and plating with bone graft for treatment of femoral shaft nonunions.
Common outcome measures
Solid union (radiographic or clinical)
Time to union
Complications (including reoperation for nonunion, malrotation, limited flexion, infection, broken nails, deep venous thrombosis, pulmonary embolism)
Operative time
Interventions
Exchange nailing:
Removal of prior intramedullary nail, over-reaming of intramedullary canal and insertion of exchange nail [Banaszkiewicz, Finkemeier, Wu 02, Hak, Weresh, Wu 97].
Plate fixation:
Plate fixation with and without autologous bone grafting leaving intramedullary nail in situ [Choi, Ueng] Removal of intramedullary nail, plate fixation with and without autologous bone grafting [Bellabarba].
Results
Solid union
Solid union (radiographic or clinical) was achieved in a smaller percentage of patients treated with exchange nailing (75%, range 56%–100%) compared with plate fixation (96%, range 91 –100%) based on pooled estimates.
There were more patients (N = 154) treated by exchange nailing [Banasziewicz, Finkemeier, Wu 02, Hak, Weresh, Wu 97] than those treated with plating (n = 55) [Choi, Bellabarba, Ueng].
Time to union
Pooled estimates of the mean time to achieve union were similar for both treatments: 5.2 months (4–9) when exchange nailing was used, and time to union 5.9 (4.2–7.2) months when plate fixation was used. [Banasziewicz, Wu 02, Wu 97, Choi, Bellabarba, Ueng].
Complications
The frequency of complications appears somewhat higher for nailing than for plate fixation. Since patients may have experienced more than one complication, the total number of complications divided by the total number of patients is reported.
The pooled estimate for the frequency of complications was 27% (0%–67%) with exchange nailing [Banasziewicz, Finkemeier, Wu 02, Weresh, Wu 97] and 18% (0%–30%) with plate fixation [Bellabarba, Ueng].
Complications described included nonunion, malrotation, limited flexion, infection, broken nails, deep venous thrombosis and pulmonary embolism.
Operative time
Pooled estimates for mean operative time were 96 minutes (36–150 minutes) for exchange nailing [Banasziewicz, Wu 97] and 125 minutes (66–164 minutes) for plate fi xation [Choi, Bellabarba].
Mike Bemelman > NetherlandsChristian van der Werken > Netherlands
IM nailing is currently the treatment of choice for the great majority of femoral shaft fractures. Surgery is really minimally invasive, the biomechanics are almost optimal, and the healing rates are very high, especially after reaming of the medullary canal. These benefits are also valid for the treatment of femoral shaft nonunions.
To our surprise the presented analysis revealed some evidence that suggests that the rates of solid union may be lower and the complication frequency higher for exchangenailing of femoral shaft nonunion than with plate fixation in combination with cancellous bone grafting on broad indication.
This evidence is only level IV—based on case series— and possibly even weaker because the presented data is extracted from a small number of mainly retrospective (8/9) clinical studies, in a heterogeneous group of patients who were treated by many different doctors and with a variety of materials and methods.
In our experience, exchange nailing with reaming of the medullary canal has several distinct advantages over plate fixation and bone grafting. Surgery is in general rather simple and elegant with a shorter operation time. Access is through an existing scar while no comorbidity (pain, physical and cosmetic) is added for surgical exposure of the nonunion area and bone graft harvesting. After nailing full weight bearing is generally the rule.
Nevertheless there are still rational indications for plate fixation, eg, nonunions in combination with a deformity, in cases in which the nail and/or locking bolds are broken (especially if the nail is solid) and in situations where the nail is inserted too deeply or through a joint.
orthopedic Trauma Directions 2007; 03; 11-21
Summary
Evidence from nine case series suggests rates of solid union may be lower and the complication frequency higher for exchange nailing of femoral shaft nonunions than with plate fixation. However, no comparative study was found to evaluate the efficacy and safety of these procedures and there were more series describing exchange nailing than plate fixation. Methodologically rigorous comparative studies with larger populations are necessary to establish the long term safety and efficacy of these two operative treatments and to evaluate the superiority of one treatment over another.
Studies for this case
Study 1
Banaszkiewicz PA, Sabboubeh A, McLeod I, et al (2003)Femoral exchange nailing for aseptic non-union: not the end to all problemsInjury; 34(5):349–356.
Study 2
Choi YS, Kim KS (2005)Plate augmentation leaving the nail in situ and bone grafting for non-union of femoral shaft fractures.Int Orthop; 29(5):287–290.
Study 3
Finkemeier CG, Chapman MW (2002)Treatment of femoral diaphyseal nonunions.Clin Orthop Relat Res; (398):223–234.
Study 4
Wu CC, Chen WJ (2002)Exchange nailing for aseptic nonunion of the femoral shaft.Int Orthop; 26(2):80–84.
Study 5
Bellabarba C, Ricci WM, Bolhofner BR (2001)Results of indirect reduction and plating of femoral shaft nonunions after intramedullary nailing.Journal of Orthopaedic Trauma; 15(4):254–263.
Study 6
Hak DJ, Lee SS, Goulet JA, et al (2000)Success of exchange reamed intramedullary nailing for femoral shaft nonunion or delayed union.J Orthop Trauma; 14(3):178–182.
Study 7
Ueng SW, Chao EK, Lee SS, et al (1997)Augmentative plate fixation for the management of femoral nonunion after intramedullary nailing.J Trauma; 43(4):640–644.
Study 8
Weresh MJ, Hakanson R, Stover MD, et al (2000)Failure of exchange reamed intramedullary nails for ununited femoral shaft fracturesJ Orthop Trauma; 14(5):335–338.
Study 9
Wu CC, Chen WJ (1997)Treatment of femoral shaft aseptic nonunions: comparison between closed and open bone-grafting techniquesJ Trauma; 43(1):112–116.
Sampling
A MEDLINE search was conducted for studies published between 1997 and 2006 comparing exchange nailing and plate fixation for treatment of femoral shaft nonunions. No comparative studies were found. Studies were excluded if there were fewer than five patients in any treatment group, if femoral nailing was not the initial treatment for the fracture or if outcomes for nonunion treatment were not separable. Studies were also excluded if there was loss of length of >1.5 cm or 1-stage femoral lengthening was done as part of the treatment. If multiple reports of the same study were found, the primary study report was included. Of 16 case-series identified, 9 remained after these exclusions and are summarized.
Objective
To critically summarize the outcomes and complications for exchange nailing and plating with bone graft for treatment of femoral shaft nonunions.
Common outcome measures
Solid union (radiographic or clinical)
Time to union
Complications (including reoperation for nonunion, malrotation, limited flexion, infection, broken nails, deep venous thrombosis, pulmonary embolism)
Operative time
Interventions
Exchange nailing:
Removal of prior intramedullary nail, over-reaming of intramedullary canal and insertion of exchange nail [Banaszkiewicz, Finkemeier, Wu 02, Hak, Weresh, Wu 97].
Plate fixation:
Plate fixation with and without autologous bone grafting leaving intramedullary nail in situ [Choi, Ueng] Removal of intramedullary nail, plate fixation with and without autologous bone grafting [Bellabarba].
Results
Solid union
Solid union (radiographic or clinical) was achieved in a smaller percentage of patients treated with exchange nailing (75%, range 56%–100%) compared with plate fixation (96%, range 91 –100%) based on pooled estimates.
There were more patients (N = 154) treated by exchange nailing [Banasziewicz, Finkemeier, Wu 02, Hak, Weresh, Wu 97] than those treated with plating (n = 55) [Choi, Bellabarba, Ueng].
Time to union
Pooled estimates of the mean time to achieve union were similar for both treatments: 5.2 months (4–9) when exchange nailing was used, and time to union 5.9 (4.2–7.2) months when plate fixation was used. [Banasziewicz, Wu 02, Wu 97, Choi, Bellabarba, Ueng].
Complications
The frequency of complications appears somewhat higher for nailing than for plate fixation. Since patients may have experienced more than one complication, the total number of complications divided by the total number of patients is reported.
The pooled estimate for the frequency of complications was 27% (0%–67%) with exchange nailing [Banasziewicz, Finkemeier, Wu 02, Weresh, Wu 97] and 18% (0%–30%) with plate fixation [Bellabarba, Ueng].
Complications described included nonunion, malrotation, limited flexion, infection, broken nails, deep venous thrombosis and pulmonary embolism.
Operative time
Pooled estimates for mean operative time were 96 minutes (36–150 minutes) for exchange nailing [Banasziewicz, Wu 97] and 125 minutes (66–164 minutes) for plate fi xation [Choi, Bellabarba].
Mike Bemelman > NetherlandsChristian van der Werken > Netherlands
IM nailing is currently the treatment of choice for the great majority of femoral shaft fractures. Surgery is really minimally invasive, the biomechanics are almost optimal, and the healing rates are very high, especially after reaming of the medullary canal. These benefits are also valid for the treatment of femoral shaft nonunions.
To our surprise the presented analysis revealed some evidence that suggests that the rates of solid union may be lower and the complication frequency higher for exchangenailing of femoral shaft nonunion than with plate fixation in combination with cancellous bone grafting on broad indication.
This evidence is only level IV—based on case series— and possibly even weaker because the presented data is extracted from a small number of mainly retrospective (8/9) clinical studies, in a heterogeneous group of patients who were treated by many different doctors and with a variety of materials and methods.
In our experience, exchange nailing with reaming of the medullary canal has several distinct advantages over plate fixation and bone grafting. Surgery is in general rather simple and elegant with a shorter operation time. Access is through an existing scar while no comorbidity (pain, physical and cosmetic) is added for surgical exposure of the nonunion area and bone graft harvesting. After nailing full weight bearing is generally the rule.
Nevertheless there are still rational indications for plate fixation, eg, nonunions in combination with a deformity, in cases in which the nail and/or locking bolds are broken (especially if the nail is solid) and in situations where the nail is inserted too deeply or through a joint.
Saturday, November 29, 2008
COMPLICATED ANKLE INJURY
30th november morning 8 am i recieved this 35 year old 38 weeks pregnant lady in my hospital with history injury when stairs collapsed at her house.. i am putting her xrays here. <>
Sunday, November 9, 2008
Materials used for AO implants - An overview and outlook
Introduction
AO implants are manufactured from a wide range of different materials. This article will provide you with an overview of the most commonly used materials and explain their clinical advantages.
The majority of metallic AO trauma implants are manufactured from Cr-Ni-Mo stainless steel, CP titanium, or Ti-6Al-7Nb alloy. A few cobalt-base alloys with commercial names such as L-605 and Elgiloy are also used for specialty implants. Nonmetallic implant materials include PEEK (polyetheretherketone) and resorbable polylactide polymers. Influences on specific material selection during the implant design phase include anatomical location, perceived stress limits, diagnostic imaging considerations, competitive factors, and most importantly, the capability to solve a clinical problem. Calcium sulfate, calcium phosphate, and other bioceramics used for bone grafting or as bone void fillers will not be covered in this review article.
Stainless steel
Implant quality 316L stainless steel meeting International Organization for Standardization (ISO), American Society for Testing and Materials (ASTM) and AO ASIF compositional, metallurgical, and mechanical requirements is used for a large number of fracture fixation devices. The wide combination of mechanical properties is ideal for a variety of implants. Some of the product features include:
Cerclage wire—ability to twist and deform without breaking.
Reconstruction plates—3-D contourability.
DHS—good fatigue strength.
Bone screws—excellent torsional strength and ductility.
Bone plates—high strength with good ductility.
The positive attributes of implant quality 316L (ISO 5832-1) are offset by a few deficiencies including the possibility of nickel allergy due to the 15% nickel content and considerable signal artifact during MRI that may interfere with diagnostic imaging. The use of Fast Spin Echo pulse sequence during MRI can reduce the amount of artifact obtained with stainless steel. Low-nickel implant stainless compositions that contain a maximum 0.05% nickel are emerging to address the nickel sensitivity problem. AOCID recently coordinated a literature survey at the Technical University Munich on low nickel sensitization in animals and humans and an AO Research Grant is funding a paravertebral patch test study of Ni-sensitized patients in Germany. Fortunately, the low-nickel implant alloys exhibit improved mechanical properties and corrosion resistance.
Titanium
Pure titanium is considered the benchmark by which all other biomaterials are judged due to its outstanding combination of long term corrosion resistance and biocompatibility. The low amount of MR artifact and ability to be anodized for color-coded implant systems are unique properties of titanium. Pure titanium can be cold worked for added strength but the majority of trauma applications include relatively low-stressed maxillofacial, cranial, and hand implants. Its overall mechanical properties are somewhat inferior to stainless steel.
Titanium alloys
α+ß titanium alloys such as Ti-6Al-7Nb offer increased strength for highly stressed AO implants such as cannulated and solid IM nails, universal spine clamps, LISS plates, thoracolumbar rods, and cannulated screws. They offer improved strength but less tensile and bending ductility when compared to pure titanium. Ti-15Mo is a relatively new ß titanium alloy with moderate strength, high ductility, and excellent notch sensitivity.
PEEK
PEEK is an advanced thermoplastic polymer that is available as an implantable material. Special synthesis methods and processing precautions control the composition, uniformity, and internal cleanliness. Current applications include vertebral spacers, spiked washers, and other implants are under development. PEEK offers good mechanical properties (100 MPa YS; 20% elongation; 170 MPa flexural strength) and radiolucency.
Fig. PEEK vertebral spacers
PEEK spiked washers are formulated with 6% barium sulfate for radiopacity as a replacement for the polyoxymethylene (POM) C spiked washer with stainless steel reinforcement ring. Unconventional machining and cleaning procedures are required to provide noncontaminated surfaces during fabrication operations. PEEK mechanical properties will not be degraded during steam autoclaving, ETO, or gamma sterilization.
Resorbable polylactide
The generalized chemical formula for polylactide polymer is (C3H4O2)n. Various isomers known as L-lactide, D-lactide, and DL-lactide refer to the structural orientation of the polymer. Isomers can be differentiated on the basis of their specific optical rotation. Amorphous (noncrystalline) 70:30 L/DLpolylactide is the primary stereoisomer used for mid-face and cranial resorbable plates, screws, and burr hole covers. The in vivo degradation mechanism is well-documented in the literature.
PLA -> lactic acid -> water + CO2
Handling operations are critical since polylactide granules are supplied in inert gas purged foil packs, stored at a low temperature, vacuum dried at a high temperature, and transferred under inert gas cover to injection molding or compression molding equipment.
Resorbable polymers are ideal for craniofacial implants because of their small mass and the low applied stress. Their excellent vascularity and 4–6 week fracture healing timeframe are favorable clinical factors. Material improvements such as higher strength and faster resorption rate plus improved implant designs will offer expanded opportunities in the future for resorbable polymers.
Surface modification
Implant surface interactions are primarily responsible for biological response and have a pronounced effect on the clinical performance of trauma products. Ongoing research by the AO Research Institute has identified the importance of metallic implant surface microtopography on the cellular reactions that are obtained. Movement between implant surface and soft tissue may cause fibrous capsule formation around a liquid filled void on stainless steel. The liquid phase allows buildup of cellular detritus, fretting debris, and possible infection. Capsule formation is not observed on titanium implants. Recent findings in Davos indicate that there is a strong correlation between lack of fine microroughness and the presence of a liquid filled void. Results have supported the hypothesis that stainless steel void formation is due to lack of microtopography and the inability of cells to adhere to surface discontinuities. Other surface modifications for implants include low friction anodizing to improve the fretting and galling resistance of titanium. Bulk coatings include HA to encourage biological fixation and antiseptic or antibiotic antibacterial films. Osteoinductive additives such as BMP-2, IGF-1, and TGF-ß1 will be applied to implant surfaces in the future to control specific biological functions.
Future developments
Substantial efforts have been made by many research groups to develop metallic foams that provide low stiffness, stable bony ingrowth, structural support, and delivery of bone forming compounds. Long-range developments are also under investigation to explore advanced material technologies such as:
Nonmagnetic amorphous metals with high strength and good wear properties.
Titanium shape memory alloys that do not contain nickel.
Nanotechnology processing to produce CP titanium with strength levels that exceed Ti-6Al-7Nb.
Novel titanium alloys that demonstrate an ultralow elastic modulus, extremely high strength, and super plasticity due to a dislocation-free plastic deformation mechanism.
Potential clinical applications for these new materials include implants with low apparent density for osteoporotic bone, improved MR or CT imaging, in vivo shape memory activation, and better resistance to fatigue fracture.
Conclusion
Successful integration of implant materials for AO implant applications is the result of close cooperation between clinicians, research scientists, material specialists, product development designers, and manufacturing engineers. Clinical feedback especially through the medical AO Expert Groups is crucial to understand the advantages, disadvantages, and limitations of conventional and advanced biomaterials. Active participation within the ISO and ASTM implant committees ensures that high quality AO material standards will be maintained on a worldwide basis. Full manufacturing support by the producers is needed to determine processing response and cost-effective manufacturing strategies for new implant materials. This team effort within the AO is responsible for providing surgical implants with improved properties and superior clinical performance
AO implants are manufactured from a wide range of different materials. This article will provide you with an overview of the most commonly used materials and explain their clinical advantages.
The majority of metallic AO trauma implants are manufactured from Cr-Ni-Mo stainless steel, CP titanium, or Ti-6Al-7Nb alloy. A few cobalt-base alloys with commercial names such as L-605 and Elgiloy are also used for specialty implants. Nonmetallic implant materials include PEEK (polyetheretherketone) and resorbable polylactide polymers. Influences on specific material selection during the implant design phase include anatomical location, perceived stress limits, diagnostic imaging considerations, competitive factors, and most importantly, the capability to solve a clinical problem. Calcium sulfate, calcium phosphate, and other bioceramics used for bone grafting or as bone void fillers will not be covered in this review article.
Stainless steel
Implant quality 316L stainless steel meeting International Organization for Standardization (ISO), American Society for Testing and Materials (ASTM) and AO ASIF compositional, metallurgical, and mechanical requirements is used for a large number of fracture fixation devices. The wide combination of mechanical properties is ideal for a variety of implants. Some of the product features include:
Cerclage wire—ability to twist and deform without breaking.
Reconstruction plates—3-D contourability.
DHS—good fatigue strength.
Bone screws—excellent torsional strength and ductility.
Bone plates—high strength with good ductility.
The positive attributes of implant quality 316L (ISO 5832-1) are offset by a few deficiencies including the possibility of nickel allergy due to the 15% nickel content and considerable signal artifact during MRI that may interfere with diagnostic imaging. The use of Fast Spin Echo pulse sequence during MRI can reduce the amount of artifact obtained with stainless steel. Low-nickel implant stainless compositions that contain a maximum 0.05% nickel are emerging to address the nickel sensitivity problem. AOCID recently coordinated a literature survey at the Technical University Munich on low nickel sensitization in animals and humans and an AO Research Grant is funding a paravertebral patch test study of Ni-sensitized patients in Germany. Fortunately, the low-nickel implant alloys exhibit improved mechanical properties and corrosion resistance.
Titanium
Pure titanium is considered the benchmark by which all other biomaterials are judged due to its outstanding combination of long term corrosion resistance and biocompatibility. The low amount of MR artifact and ability to be anodized for color-coded implant systems are unique properties of titanium. Pure titanium can be cold worked for added strength but the majority of trauma applications include relatively low-stressed maxillofacial, cranial, and hand implants. Its overall mechanical properties are somewhat inferior to stainless steel.
Titanium alloys
α+ß titanium alloys such as Ti-6Al-7Nb offer increased strength for highly stressed AO implants such as cannulated and solid IM nails, universal spine clamps, LISS plates, thoracolumbar rods, and cannulated screws. They offer improved strength but less tensile and bending ductility when compared to pure titanium. Ti-15Mo is a relatively new ß titanium alloy with moderate strength, high ductility, and excellent notch sensitivity.
PEEK
PEEK is an advanced thermoplastic polymer that is available as an implantable material. Special synthesis methods and processing precautions control the composition, uniformity, and internal cleanliness. Current applications include vertebral spacers, spiked washers, and other implants are under development. PEEK offers good mechanical properties (100 MPa YS; 20% elongation; 170 MPa flexural strength) and radiolucency.
Fig. PEEK vertebral spacers
PEEK spiked washers are formulated with 6% barium sulfate for radiopacity as a replacement for the polyoxymethylene (POM) C spiked washer with stainless steel reinforcement ring. Unconventional machining and cleaning procedures are required to provide noncontaminated surfaces during fabrication operations. PEEK mechanical properties will not be degraded during steam autoclaving, ETO, or gamma sterilization.
Resorbable polylactide
The generalized chemical formula for polylactide polymer is (C3H4O2)n. Various isomers known as L-lactide, D-lactide, and DL-lactide refer to the structural orientation of the polymer. Isomers can be differentiated on the basis of their specific optical rotation. Amorphous (noncrystalline) 70:30 L/DLpolylactide is the primary stereoisomer used for mid-face and cranial resorbable plates, screws, and burr hole covers. The in vivo degradation mechanism is well-documented in the literature.
PLA -> lactic acid -> water + CO2
Handling operations are critical since polylactide granules are supplied in inert gas purged foil packs, stored at a low temperature, vacuum dried at a high temperature, and transferred under inert gas cover to injection molding or compression molding equipment.
Resorbable polymers are ideal for craniofacial implants because of their small mass and the low applied stress. Their excellent vascularity and 4–6 week fracture healing timeframe are favorable clinical factors. Material improvements such as higher strength and faster resorption rate plus improved implant designs will offer expanded opportunities in the future for resorbable polymers.
Surface modification
Implant surface interactions are primarily responsible for biological response and have a pronounced effect on the clinical performance of trauma products. Ongoing research by the AO Research Institute has identified the importance of metallic implant surface microtopography on the cellular reactions that are obtained. Movement between implant surface and soft tissue may cause fibrous capsule formation around a liquid filled void on stainless steel. The liquid phase allows buildup of cellular detritus, fretting debris, and possible infection. Capsule formation is not observed on titanium implants. Recent findings in Davos indicate that there is a strong correlation between lack of fine microroughness and the presence of a liquid filled void. Results have supported the hypothesis that stainless steel void formation is due to lack of microtopography and the inability of cells to adhere to surface discontinuities. Other surface modifications for implants include low friction anodizing to improve the fretting and galling resistance of titanium. Bulk coatings include HA to encourage biological fixation and antiseptic or antibiotic antibacterial films. Osteoinductive additives such as BMP-2, IGF-1, and TGF-ß1 will be applied to implant surfaces in the future to control specific biological functions.
Future developments
Substantial efforts have been made by many research groups to develop metallic foams that provide low stiffness, stable bony ingrowth, structural support, and delivery of bone forming compounds. Long-range developments are also under investigation to explore advanced material technologies such as:
Nonmagnetic amorphous metals with high strength and good wear properties.
Titanium shape memory alloys that do not contain nickel.
Nanotechnology processing to produce CP titanium with strength levels that exceed Ti-6Al-7Nb.
Novel titanium alloys that demonstrate an ultralow elastic modulus, extremely high strength, and super plasticity due to a dislocation-free plastic deformation mechanism.
Potential clinical applications for these new materials include implants with low apparent density for osteoporotic bone, improved MR or CT imaging, in vivo shape memory activation, and better resistance to fatigue fracture.
Conclusion
Successful integration of implant materials for AO implant applications is the result of close cooperation between clinicians, research scientists, material specialists, product development designers, and manufacturing engineers. Clinical feedback especially through the medical AO Expert Groups is crucial to understand the advantages, disadvantages, and limitations of conventional and advanced biomaterials. Active participation within the ISO and ASTM implant committees ensures that high quality AO material standards will be maintained on a worldwide basis. Full manufacturing support by the producers is needed to determine processing response and cost-effective manufacturing strategies for new implant materials. This team effort within the AO is responsible for providing surgical implants with improved properties and superior clinical performance
Thursday, October 23, 2008
PLACEBO EFFECT
More than half of doctors offer fake prescriptions to make patients feel better -- and that's OK, most doctors say.
The findings come from a survey of 679 internists and rheumatologists. Doctors in these specialties often see patients with chronic illnesses or chronic pains that are difficult, if not impossible, to cure. Sometimes fake medicine -- placebos -- make such patients feel better.
Fake drugs can have very real benefits. It's called the placebo effect. In clinical trials, many patients who receive placebos do better than real-world patients who get no treatment at all, notes study researcher Jon C. Tilburt, MD.
"Twenty to thirty percent of the benefit seen in rheumatism drug studies are due to the placebo effect. Real changes in health go along with the belief that patients will get better," Tilburt tells WebMD.
Tilburt and colleagues asked the doctors a series of questions, each a bit more blunt than the last:
If a clinical trial showed a sugar pill was better than no treatment for fibromyalgia, would you recommend sugar pills to fibromyalgia patients? Yes, 58% of the doctors said.
Do you ever actually recommend treatments primarily to enhance a patient's expectations? Yes, 80% of the doctors said.
In the last year, did you recommend a placebo treatment to a patient? Yes, 55% of the doctors said.
What did the doctors actually tell their patients? Over two-thirds of those who prescribed placebos told patients they were getting "medicine not typically used for your condition but which might benefit you."
Is it "appropriate" to fool patients this way? Yes, 62% of the doctors said.
"I don't think doctors have anything but the patients' best interest in mind when they give a placebo prescription," says Tilburt. "They are thinking about both the physical and psychological well-being of the patient."
The hard-to-accept truth is that doctors don't have proven treatments for many of the ills that plague their patients.
"With untreatable conditions or chronic conditions when we have run out of treatments, doctors are willing to try virtually anything -- if they are convinced it is safe -- to make the patient feel better, even if the mechanism is a psychological mechanism," Tilburt says.
Placebo Prescriptions: Right or Wrong?
Is it right for doctors to prescribe treatments they believe are not biochemically effective?
Here's the official policy of the American Medical Association:
Use of a placebo without the patient's knowledge may undermine trust, compromise the patient-physician relationship, and result in medical harm to the patient.
A placebo must not be given merely to mollify a difficult patient, because doing so serves the convenience of the physician more than it promotes the patient's welfare.
Physicians may use placebos for diagnosis or treatment only if the patient is informed of and agrees to its use.
Placebo Prescriptions: Right or Wrong?
That last point seems tricky. How can a fake drug work if a patient knows it is fake?
The AMA policy says doctors should explain to patients that they can better understand their condition if they try different medicines, including a placebo. If the patient agrees to this, the doctor does not have to identify which medicine is fake, nor does the doctor have to get the patient's specific consent before giving the patient the fake treatment.
There's nothing wrong with this approach, says medical ethicist Arthur Caplan, PhD, professor of bioethics at the University of Pennsylvania, Philadelphia.
"It is ethical to use treatments that are low risk and have few side effects if you can relieve people's symptoms," Caplan tells WebMD. "Placebos are especially useful in the treatment of the psychological aspects of disease. Most doctors will tell you they have used placebos."
But doctors do often prescribe placebos the wrong way. In today's world, a doctor can't write a prescription for a sugar pill. The doctor has to prescribe something -- and every active medicine carries some risk of side effects.
"What you can use as a placebo is complicated. I have seen people dispensing antibiotics as placebo for mothers who want something for their kids' flu," Caplan says. "Not only does this not help, but it does build up drug resistance and may have some serious side effects for the child."
Most doctors use relatively harmless drugs, such as baby aspirin, as placebos. Clearly, great care must be taken to ensure that the placebo drug's risk is less than the benefit of the hoped-for placebo effect.
"We know it is wrong when doctors give potentially harmful medicines in a manner that may not be warranted," Tilburt says. "If I think it will actually have only a placebo effect, I should not give a patient a sedative. The compulsion by doctors to benevolently promote patient expectations can play out in a way harmful to patients."
In the end, Tilburt suggests, the effectiveness of a placebo treatment may well hinge on the trust patients have in their doctors.
"Maybe it isn't about taking a pill at all," he says. "Maybe it is the relationship between the doctor and the patient that makes the real difference."
Tilburt, formerly with the bioethics department of the National Institutes of Health, is now assistant professor of medicine at the Mayo Clinic, Rochester, Minn. The study appears in the Oct. 24 online first edition of the journal BMJ.
The findings come from a survey of 679 internists and rheumatologists. Doctors in these specialties often see patients with chronic illnesses or chronic pains that are difficult, if not impossible, to cure. Sometimes fake medicine -- placebos -- make such patients feel better.
Fake drugs can have very real benefits. It's called the placebo effect. In clinical trials, many patients who receive placebos do better than real-world patients who get no treatment at all, notes study researcher Jon C. Tilburt, MD.
"Twenty to thirty percent of the benefit seen in rheumatism drug studies are due to the placebo effect. Real changes in health go along with the belief that patients will get better," Tilburt tells WebMD.
Tilburt and colleagues asked the doctors a series of questions, each a bit more blunt than the last:
If a clinical trial showed a sugar pill was better than no treatment for fibromyalgia, would you recommend sugar pills to fibromyalgia patients? Yes, 58% of the doctors said.
Do you ever actually recommend treatments primarily to enhance a patient's expectations? Yes, 80% of the doctors said.
In the last year, did you recommend a placebo treatment to a patient? Yes, 55% of the doctors said.
What did the doctors actually tell their patients? Over two-thirds of those who prescribed placebos told patients they were getting "medicine not typically used for your condition but which might benefit you."
Is it "appropriate" to fool patients this way? Yes, 62% of the doctors said.
"I don't think doctors have anything but the patients' best interest in mind when they give a placebo prescription," says Tilburt. "They are thinking about both the physical and psychological well-being of the patient."
The hard-to-accept truth is that doctors don't have proven treatments for many of the ills that plague their patients.
"With untreatable conditions or chronic conditions when we have run out of treatments, doctors are willing to try virtually anything -- if they are convinced it is safe -- to make the patient feel better, even if the mechanism is a psychological mechanism," Tilburt says.
Placebo Prescriptions: Right or Wrong?
Is it right for doctors to prescribe treatments they believe are not biochemically effective?
Here's the official policy of the American Medical Association:
Use of a placebo without the patient's knowledge may undermine trust, compromise the patient-physician relationship, and result in medical harm to the patient.
A placebo must not be given merely to mollify a difficult patient, because doing so serves the convenience of the physician more than it promotes the patient's welfare.
Physicians may use placebos for diagnosis or treatment only if the patient is informed of and agrees to its use.
Placebo Prescriptions: Right or Wrong?
That last point seems tricky. How can a fake drug work if a patient knows it is fake?
The AMA policy says doctors should explain to patients that they can better understand their condition if they try different medicines, including a placebo. If the patient agrees to this, the doctor does not have to identify which medicine is fake, nor does the doctor have to get the patient's specific consent before giving the patient the fake treatment.
There's nothing wrong with this approach, says medical ethicist Arthur Caplan, PhD, professor of bioethics at the University of Pennsylvania, Philadelphia.
"It is ethical to use treatments that are low risk and have few side effects if you can relieve people's symptoms," Caplan tells WebMD. "Placebos are especially useful in the treatment of the psychological aspects of disease. Most doctors will tell you they have used placebos."
But doctors do often prescribe placebos the wrong way. In today's world, a doctor can't write a prescription for a sugar pill. The doctor has to prescribe something -- and every active medicine carries some risk of side effects.
"What you can use as a placebo is complicated. I have seen people dispensing antibiotics as placebo for mothers who want something for their kids' flu," Caplan says. "Not only does this not help, but it does build up drug resistance and may have some serious side effects for the child."
Most doctors use relatively harmless drugs, such as baby aspirin, as placebos. Clearly, great care must be taken to ensure that the placebo drug's risk is less than the benefit of the hoped-for placebo effect.
"We know it is wrong when doctors give potentially harmful medicines in a manner that may not be warranted," Tilburt says. "If I think it will actually have only a placebo effect, I should not give a patient a sedative. The compulsion by doctors to benevolently promote patient expectations can play out in a way harmful to patients."
In the end, Tilburt suggests, the effectiveness of a placebo treatment may well hinge on the trust patients have in their doctors.
"Maybe it isn't about taking a pill at all," he says. "Maybe it is the relationship between the doctor and the patient that makes the real difference."
Tilburt, formerly with the bioethics department of the National Institutes of Health, is now assistant professor of medicine at the Mayo Clinic, Rochester, Minn. The study appears in the Oct. 24 online first edition of the journal BMJ.
Wednesday, October 15, 2008
ACL RECONSTRUCTION
http://http://www.hipsknees.info/flash5/HTML/demo.html
this is the link to understand the surgical procedure of reconstruction of ACL using bone tendon bone method... this is for patients information.. u need to instal java to run this movie..
Sunday, October 12, 2008
Computer-Assisted Knee Surgery
Computer-assisted surgery helps surgeons align the patient's bones and knee replacement implants with a degree of accuracy not possible with the naked eye. For the first time, doctors have detailed information allowing them to balance the ligaments and it is given to them before they make the necessary cuts.
Computers also help doctors who use smaller incisions instead of the traditional larger openings. Small-incision surgery, most often referred to as minimally invasive surgery, offers the potential for faster recovery, less bleeding and less pain for patients.
Think of it this way. Perhaps you've seen the on-board computers in newer cars that provide driving directions using satellite navigation systems. On-board computers collect data points from satellites and use precise coordinates to give drivers directions from point A to point B. It provides a degree of precision, speed and accuracy not attainable with a map and compass.
Similarly, computers used during orthopaedic surgeries offer visual mapping to help doctors make crucial decisions before and throughout the knee replacement operation. The objective is to combine the precision and accuracy of computer technology with the surgeon's skill to perform surgery.
An advantage is that the doctor has greater "vision" when it counts — during surgery. This supports decision-making and enhances the surgeon's flexibility.
Here's how it works. Computer-assisted surgery uses:
the computer system
cameras
software
specialized surgical instruments
physician training The software and instrumentation of the Ci™ System are designed to work together. (Some systems use traditional surgical tools that must be adapted for use with computers). Imaging technology allows the surgeon to see a computer generated picture representation of a patient's knee joint allowing them the potential to operate with smaller openings and with more precision.
Visual Mapping of Knee Joint
The Ci™ System's lightweight, wireless computer system is used with a small camera array. A digital model is produced that serves as a map for each operation. The cameras take data via infrared signals from reflectors placed on the patient's body and on specially designed surgical instruments. The computer uses the data to track the exact position of the patient and the instruments on a monitor. The combination of computer visualization and special surgical instruments allows doctors to align the knee replacement implant with greater precision than when doing the procedure with the naked eye.
Advocates of the technology say they expect the use of computer-aided surgery to spread rapidly in the next decade because of the following potential benefits:
support for the doctor in pre-operative planning
intra-operative flexibility to adapt the plan based on the data shown during the surgery
improved surgical accuracy and consistency
The future of computer-assisted surgery is exciting and promising. Total joint replacement is a proven procedure that has been successful for decades in helping people live with less pain and greater mobility. Some surgeons will adapt the technology right away; others will await further results while adhering to the traditional hands-on approach they've used for years.
The way a knee replacement will perform depends on your age, weight, activity level and other factors. There are potential risks and recovery takes time. If you have conditions that limit rehabilitation, you should not have this surgery. Only your orthopaedic surgeon can decide whether partial or total knee replacement is right for you.
Computers also help doctors who use smaller incisions instead of the traditional larger openings. Small-incision surgery, most often referred to as minimally invasive surgery, offers the potential for faster recovery, less bleeding and less pain for patients.
Think of it this way. Perhaps you've seen the on-board computers in newer cars that provide driving directions using satellite navigation systems. On-board computers collect data points from satellites and use precise coordinates to give drivers directions from point A to point B. It provides a degree of precision, speed and accuracy not attainable with a map and compass.
Similarly, computers used during orthopaedic surgeries offer visual mapping to help doctors make crucial decisions before and throughout the knee replacement operation. The objective is to combine the precision and accuracy of computer technology with the surgeon's skill to perform surgery.
An advantage is that the doctor has greater "vision" when it counts — during surgery. This supports decision-making and enhances the surgeon's flexibility.
Here's how it works. Computer-assisted surgery uses:
the computer system
cameras
software
specialized surgical instruments
physician training The software and instrumentation of the Ci™ System are designed to work together. (Some systems use traditional surgical tools that must be adapted for use with computers). Imaging technology allows the surgeon to see a computer generated picture representation of a patient's knee joint allowing them the potential to operate with smaller openings and with more precision.
Visual Mapping of Knee Joint
The Ci™ System's lightweight, wireless computer system is used with a small camera array. A digital model is produced that serves as a map for each operation. The cameras take data via infrared signals from reflectors placed on the patient's body and on specially designed surgical instruments. The computer uses the data to track the exact position of the patient and the instruments on a monitor. The combination of computer visualization and special surgical instruments allows doctors to align the knee replacement implant with greater precision than when doing the procedure with the naked eye.
Advocates of the technology say they expect the use of computer-aided surgery to spread rapidly in the next decade because of the following potential benefits:
support for the doctor in pre-operative planning
intra-operative flexibility to adapt the plan based on the data shown during the surgery
improved surgical accuracy and consistency
The future of computer-assisted surgery is exciting and promising. Total joint replacement is a proven procedure that has been successful for decades in helping people live with less pain and greater mobility. Some surgeons will adapt the technology right away; others will await further results while adhering to the traditional hands-on approach they've used for years.
The way a knee replacement will perform depends on your age, weight, activity level and other factors. There are potential risks and recovery takes time. If you have conditions that limit rehabilitation, you should not have this surgery. Only your orthopaedic surgeon can decide whether partial or total knee replacement is right for you.
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