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Harry Hothi - One of the best experts on this subject based on the ideXlab platform.
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wear analysis of tapers from failed metal on polyethylene hips provides first data on clinically significant doses of cobalt and chromium for adverse reaction to metal debris
Orthopaedic Proceedings, 2018Co-Authors: Harry Hothi, Joha Henckel, Clive P Duncan, Donald S Garbuz, J Skinner, Alister HartAbstract:Trunnionosis, due to mechanical wear and/or corrosion at the head stem taper junction, can occur in metal on polyethylene (MOP) hip implants. In some patients this results in severe soft tissue destruction or Adverse Reaction to Metal Debris (ARMD). The amount of Material required to cause ARMD is unknown but analyses of retrieved hips may provide the answer to this clinically important question.We collected implants from 20 patients with failed hips with MOP bearings, revised due to ARMD. We collected clinical, imaging and blood test data. We graded the severity of taper corrosion (1 to 4), and quantified the volume of Material Loss from this junction. We compared our results with previous data collected for metal-on-metal (MOM) hips.The median time to revision of the MOP hips was 51.3 (23.1–56.4) months. All head tapers were moderately to severely corroded with a median corrosion score of 4. The median (range) of total Material Loss at the taper of the MOP hips was 3.9 mm3 (2.96 – 7.85 mm3) and the mate...
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effect of bearing type on taper Material Loss in hips from 1 manufacturer
Journal of Arthroplasty, 2017Co-Authors: Harry Hothi, Antti Eskeline, Joha Henckel, Youngmi Kwo, J A SkinneAbstract:BACKGROUND: Numerous studies have reported on clinical significant volumes of Material Loss and corrosion at the head-stem junction of metal-on-metal (MOM) hips; less is understood about metal-on-polyethylene (MOP) hips. We compared the effect of bearing type (MOM vs MOP) on taper Material Loss for a hip system of a single design. METHODS: In this cohort study, we recruited retrieved MOM (n = 30) and MOP (n = 22) bearing hips that were consecutively received at our center. We prospectively collected associated clinical and imaging data. We measured the severity of corrosion and volumes of Material Loss at each head taper surface and used multivariate statistical analysis to investigate differences between the 2 bearing types. RESULTS: The median rate of Material Loss for the MOM and MOP groups was 0.81 mm3/y (0.01-3.45) and 0.03 mm3/y (0-1.07), respectively (P < .001). Twenty-nine of 30 MOM hips were revised for adverse metal reactions, compared with 1 of 22 MOP hips. CONCLUSION: MOP hips lost significantly less Material from their taper junctions than MOM hips. Our results can reassure patients with MOP Pinnacle hips that they are unlikely to experience clinically significant problems related to Material Loss from the taper junction.
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variation in taper surface roughness for a single design effects the wear rate in total hip arthroplasty
Journal of Orthopaedic Research, 2017Co-Authors: Robert K Whittaker, Harry Hothi, J A Skinner, G W Blunn, Antti Eskelinen, A HartAbstract:Material Loss from the head-stem taper junction of total hip arthroplasty (THA) is implicated in adverse reactions to metal debris (ARMD); the mechanisms for this are multi-factorial. We investigated the relationship between the roughness of the "as manufactured" taper surface and the wear rate from this junction. Fifty retrieved Pinnacle metal-on-metal (MOM) bearings paired with a Corail stem were included in the study. Multivariable statistical analysis was performed to determine the influence of taper roughness on Material Loss rate after controlling for other confounding surgical, implant, and patient factors. The surface roughness of the "as manufactured" head taper surface was associated with the rate of Material Loss from this surface. Four of eighteen roughness variables taken from ISO 4,287 and ISO 13,565-2 were significant: The Reduced Peak Height (Rpk, the protruding peaks above the core) (p = 0.004), Material Ratio 1 (Mr1, the ratio of the protruding peaks above the core) (p = 0.002), Area of the Peak Region (A1, the area of the Abbott-Curve that contains the peaks from the profile) (p = 0.003) and the Skewness (Rsk, the asymmetry of the height distribution corresponding to the height or depth of surface features) (p = 0.03). We found a large variability in the measured values with a median (range) of 0.50 (0.05-2.98), 11.98 (0.46-39.98), 30.89 (0.15-581.00), and 0.04 (-0.73-0.84), respectively. A 1-unit increase in Rpk was associated with a 73% increase in the taper wear rate. The variability of "as manufactured" surface roughness has a significant effect on taper Material Loss. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
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wear analysis of tapers from failed metal on polyethylene hips provides first data on clinically significant doses of cobalt and chromium for adverse reaction to metal debris
Journal of Bone and Joint Surgery-british Volume, 2017Co-Authors: Harry Hothi, Joha Henckel, Clive P Duncan, Donald S Garbuz, J Skinner, Alister HartAbstract:Trunnionosis, due to mechanical wear and/or corrosion at the head stem taper junction, can occur in metal on polyethylene (MOP) hip implants. In some patients this results in severe soft tissue destruction or Adverse Reaction to Metal Debris (ARMD). The amount of Material required to cause ARMD is unknown but analyses of retrieved hips may provide the answer to this clinically important question. We collected implants from 20 patients with failed hips with MOP bearings, revised due to ARMD. We collected clinical, imaging and blood test data. We graded the severity of taper corrosion (1 to 4), and quantified the volume of Material Loss from this junction. We compared our results with previous data collected for metal-on-metal (MOM) hips. The median time to revision of the MOP hips was 51.3 (23.1–56.4) months. All head tapers were moderately to severely corroded with a median corrosion score of 4. The median (range) of total Material Loss at the taper of the MOP hips was 3.9 mm 3 (2.96 – 7.85 mm 3 ) and the Material Loss rate was 1.4 mm 3 / year (0.56 – 1.82). Comparison with MOM hips revealed no significant difference in taper Material Loss (p=0.7344) with a median rate of 0.81 mm 3 / year (0.01–3.45). We are the first to quantify the volume of Material Loss at the head taper of hip implants with MOP bearings that were revised due to trunnionosis. This data indicates that a clinically significant dose of cobalt and chromium to induce ARMD is approximately 1.4 mm 3 / year. We have identified a clinically significant volume of taper Material Loss in MOP hips.
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damage patterns at the head stem taper junction helps understand the mechanisms of Material Loss
Journal of Arthroplasty, 2017Co-Authors: Harry Hothi, Andreas Panagiotopoulos, Robert K Whittaker, Paul J Bills, Rebecca A Mcmillan, J A Skinner, Alister HartAbstract:Abstract Background Material Loss at the taper junction of metal-on-metal total hip arthroplasties has been implicated in their early failure. The mechanisms of Material Loss are not fully understood; analysis of the patterns of damage at the taper can help us better understand why Material Loss occurs at this junction. Methods We mapped the patterns of Material Loss in a series of 155 metal-on-metal total hip arthroplasties received at our center by scanning the taper surface using a roundness-measuring machine. We examined these Material Loss maps to develop a 5-tier classification system based on visual differences between different patterns. We correlated these patterns to surgical, implant, and patient factors known to be important for head-stem taper damage. Results We found that 63 implants had "minimal damage" at the taper (Material Loss 3 ), and the remaining 92 implants could be categorized by 4 distinct patterns of taper Material Loss. We found that (1) head diameter and (2) time to revision were key significant variables separating the groups. Conclusion These Material Loss maps allow us to suggest different mechanisms that dominate the cause of the Material Loss in each pattern: (1) corrosion, (2) mechanically assisted corrosion, or (3) intraoperative damage or poor size tolerances leading to toggling of trunnion in taper.
Alister Hart - One of the best experts on this subject based on the ideXlab platform.
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wear analysis of tapers from failed metal on polyethylene hips provides first data on clinically significant doses of cobalt and chromium for adverse reaction to metal debris
Orthopaedic Proceedings, 2018Co-Authors: Harry Hothi, Joha Henckel, Clive P Duncan, Donald S Garbuz, J Skinner, Alister HartAbstract:Trunnionosis, due to mechanical wear and/or corrosion at the head stem taper junction, can occur in metal on polyethylene (MOP) hip implants. In some patients this results in severe soft tissue destruction or Adverse Reaction to Metal Debris (ARMD). The amount of Material required to cause ARMD is unknown but analyses of retrieved hips may provide the answer to this clinically important question.We collected implants from 20 patients with failed hips with MOP bearings, revised due to ARMD. We collected clinical, imaging and blood test data. We graded the severity of taper corrosion (1 to 4), and quantified the volume of Material Loss from this junction. We compared our results with previous data collected for metal-on-metal (MOM) hips.The median time to revision of the MOP hips was 51.3 (23.1–56.4) months. All head tapers were moderately to severely corroded with a median corrosion score of 4. The median (range) of total Material Loss at the taper of the MOP hips was 3.9 mm3 (2.96 – 7.85 mm3) and the mate...
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wear analysis of tapers from failed metal on polyethylene hips provides first data on clinically significant doses of cobalt and chromium for adverse reaction to metal debris
Journal of Bone and Joint Surgery-british Volume, 2017Co-Authors: Harry Hothi, Joha Henckel, Clive P Duncan, Donald S Garbuz, J Skinner, Alister HartAbstract:Trunnionosis, due to mechanical wear and/or corrosion at the head stem taper junction, can occur in metal on polyethylene (MOP) hip implants. In some patients this results in severe soft tissue destruction or Adverse Reaction to Metal Debris (ARMD). The amount of Material required to cause ARMD is unknown but analyses of retrieved hips may provide the answer to this clinically important question. We collected implants from 20 patients with failed hips with MOP bearings, revised due to ARMD. We collected clinical, imaging and blood test data. We graded the severity of taper corrosion (1 to 4), and quantified the volume of Material Loss from this junction. We compared our results with previous data collected for metal-on-metal (MOM) hips. The median time to revision of the MOP hips was 51.3 (23.1–56.4) months. All head tapers were moderately to severely corroded with a median corrosion score of 4. The median (range) of total Material Loss at the taper of the MOP hips was 3.9 mm 3 (2.96 – 7.85 mm 3 ) and the Material Loss rate was 1.4 mm 3 / year (0.56 – 1.82). Comparison with MOM hips revealed no significant difference in taper Material Loss (p=0.7344) with a median rate of 0.81 mm 3 / year (0.01–3.45). We are the first to quantify the volume of Material Loss at the head taper of hip implants with MOP bearings that were revised due to trunnionosis. This data indicates that a clinically significant dose of cobalt and chromium to induce ARMD is approximately 1.4 mm 3 / year. We have identified a clinically significant volume of taper Material Loss in MOP hips.
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damage patterns at the head stem taper junction helps understand the mechanisms of Material Loss
Journal of Arthroplasty, 2017Co-Authors: Harry Hothi, Andreas Panagiotopoulos, Robert K Whittaker, Paul J Bills, Rebecca A Mcmillan, J A Skinner, Alister HartAbstract:Abstract Background Material Loss at the taper junction of metal-on-metal total hip arthroplasties has been implicated in their early failure. The mechanisms of Material Loss are not fully understood; analysis of the patterns of damage at the taper can help us better understand why Material Loss occurs at this junction. Methods We mapped the patterns of Material Loss in a series of 155 metal-on-metal total hip arthroplasties received at our center by scanning the taper surface using a roundness-measuring machine. We examined these Material Loss maps to develop a 5-tier classification system based on visual differences between different patterns. We correlated these patterns to surgical, implant, and patient factors known to be important for head-stem taper damage. Results We found that 63 implants had "minimal damage" at the taper (Material Loss 3 ), and the remaining 92 implants could be categorized by 4 distinct patterns of taper Material Loss. We found that (1) head diameter and (2) time to revision were key significant variables separating the groups. Conclusion These Material Loss maps allow us to suggest different mechanisms that dominate the cause of the Material Loss in each pattern: (1) corrosion, (2) mechanically assisted corrosion, or (3) intraoperative damage or poor size tolerances leading to toggling of trunnion in taper.
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influence of stem type on Material Loss at the metal on metal pinnacle taper junction
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART H-JOURNAL OF ENGINEERING IN MEDICINE 229 (1) pp. 91-97. (2015), 2015Co-Authors: Harry Hothi, Robert K Whittaker, J A Skinner, G W Blunn, Jay Meswania, Alister HartAbstract:The clinical importance of Material Loss at the head–stem junction is unknown. Comparison of retrievals with different stem types can provide the opportunity to understand the importance of the tap...
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the reliability of a scoring system for corrosion and fretting and its relationship to Material Loss of tapered modular junctions of retrieved hip implants
Journal of Arthroplasty, 2014Co-Authors: Harry Hothi, Robert K Whittaker, J A Skinner, Ashley K Matthies, Reshid Berber, Alister HartAbstract:Abstract It has been suggested that corrosion and fretting at the tapered, modular junctions of hip arthroplasties may contribute to implant failure. In this study the reliability of a commonly used peer-reviewed scoring system for visual assessment of corrosion and fretting at these junctions was evaluated. Volumetric Material Loss at the tapered head surface was measured and associations with the visual scores were investigated. We found that the inter-observer reproducibility and single-observer repeatability of the corrosion scores were substantial using Cohen's weighted Kappa statistic (k=0.64–0.71). The reproducibility and repeatability of the fretting scores however were slight to fair (k=0.18–0.31). Taper corrosion scores were significantly and moderately correlated with the volume of Material Loss measured (Spearman's r=0.59; P
A Hart - One of the best experts on this subject based on the ideXlab platform.
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variation in taper surface roughness for a single design effects the wear rate in total hip arthroplasty
Journal of Orthopaedic Research, 2017Co-Authors: Robert K Whittaker, Harry Hothi, J A Skinner, G W Blunn, Antti Eskelinen, A HartAbstract:Material Loss from the head-stem taper junction of total hip arthroplasty (THA) is implicated in adverse reactions to metal debris (ARMD); the mechanisms for this are multi-factorial. We investigated the relationship between the roughness of the "as manufactured" taper surface and the wear rate from this junction. Fifty retrieved Pinnacle metal-on-metal (MOM) bearings paired with a Corail stem were included in the study. Multivariable statistical analysis was performed to determine the influence of taper roughness on Material Loss rate after controlling for other confounding surgical, implant, and patient factors. The surface roughness of the "as manufactured" head taper surface was associated with the rate of Material Loss from this surface. Four of eighteen roughness variables taken from ISO 4,287 and ISO 13,565-2 were significant: The Reduced Peak Height (Rpk, the protruding peaks above the core) (p = 0.004), Material Ratio 1 (Mr1, the ratio of the protruding peaks above the core) (p = 0.002), Area of the Peak Region (A1, the area of the Abbott-Curve that contains the peaks from the profile) (p = 0.003) and the Skewness (Rsk, the asymmetry of the height distribution corresponding to the height or depth of surface features) (p = 0.03). We found a large variability in the measured values with a median (range) of 0.50 (0.05-2.98), 11.98 (0.46-39.98), 30.89 (0.15-581.00), and 0.04 (-0.73-0.84), respectively. A 1-unit increase in Rpk was associated with a 73% increase in the taper wear rate. The variability of "as manufactured" surface roughness has a significant effect on taper Material Loss. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
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Material Loss at the taper junction of retrieved large head metal on metal total hip replacements
Journal of Orthopaedic Research, 2013Co-Authors: Ashley K Matthies, Paul J Bills, Radu Racasan, Liam Blunt, Suzie Cro, A Panagiotidou, G W Blunn, John A Skinner, A HartAbstract:It has been speculated that Material Loss, either as corrosion or wear, at the head-stem taper junction is implicated in the high revision rates reported for metal-on-metal total hip replacements. We measured the volume of Material Loss from the taper and bearing surfaces of retrieved devices, and investigated the associations with blood metal ion levels and the diagnosis of a cystic or solid pseudotumor. The median volumes of Material lost from the female and male taper surfaces were 2.0 and 0.29 mm 3 , respectively, while the median volumes of wear from the cup and head bearing surfaces were 1.94 and 3.44 mm 3 , respectively. Material Loss from the female taper was similar to that from the acetabular bearing surface (p ¼ 0.55), but significantly less than that from the femoral bearing surface (p < 0.001). Material Loss from the male taper was less than that from both bearing surfaces (p < 0.001). Multivariable analysis demonstrated no significant correlations between the volume of Material lost from the taper surfaces and either blood cobalt or chromium ions, or the presence of pseudotumor. While a substantial volume of Material is lost at the taper junction, the clinical significance of this debris remains unclear. 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1677-1685, 2013 Uncemented stemmed metal-on-metal (MOM) bearings have higher revision rates compared to all other bearing systems used for hip replacement. The Nation- al Joint Registry of England and Wales reported a 5- year revision rate of 6.96% for MOM total hip replace- ments. This compares to <3% for all other conventional hip replacements (MOP, COC, COP), and 4.56% for
Robert K Whittaker - One of the best experts on this subject based on the ideXlab platform.
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variation in taper surface roughness for a single design effects the wear rate in total hip arthroplasty
Journal of Orthopaedic Research, 2017Co-Authors: Robert K Whittaker, Harry Hothi, J A Skinner, G W Blunn, Antti Eskelinen, A HartAbstract:Material Loss from the head-stem taper junction of total hip arthroplasty (THA) is implicated in adverse reactions to metal debris (ARMD); the mechanisms for this are multi-factorial. We investigated the relationship between the roughness of the "as manufactured" taper surface and the wear rate from this junction. Fifty retrieved Pinnacle metal-on-metal (MOM) bearings paired with a Corail stem were included in the study. Multivariable statistical analysis was performed to determine the influence of taper roughness on Material Loss rate after controlling for other confounding surgical, implant, and patient factors. The surface roughness of the "as manufactured" head taper surface was associated with the rate of Material Loss from this surface. Four of eighteen roughness variables taken from ISO 4,287 and ISO 13,565-2 were significant: The Reduced Peak Height (Rpk, the protruding peaks above the core) (p = 0.004), Material Ratio 1 (Mr1, the ratio of the protruding peaks above the core) (p = 0.002), Area of the Peak Region (A1, the area of the Abbott-Curve that contains the peaks from the profile) (p = 0.003) and the Skewness (Rsk, the asymmetry of the height distribution corresponding to the height or depth of surface features) (p = 0.03). We found a large variability in the measured values with a median (range) of 0.50 (0.05-2.98), 11.98 (0.46-39.98), 30.89 (0.15-581.00), and 0.04 (-0.73-0.84), respectively. A 1-unit increase in Rpk was associated with a 73% increase in the taper wear rate. The variability of "as manufactured" surface roughness has a significant effect on taper Material Loss. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
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damage patterns at the head stem taper junction helps understand the mechanisms of Material Loss
Journal of Arthroplasty, 2017Co-Authors: Harry Hothi, Andreas Panagiotopoulos, Robert K Whittaker, Paul J Bills, Rebecca A Mcmillan, J A Skinner, Alister HartAbstract:Abstract Background Material Loss at the taper junction of metal-on-metal total hip arthroplasties has been implicated in their early failure. The mechanisms of Material Loss are not fully understood; analysis of the patterns of damage at the taper can help us better understand why Material Loss occurs at this junction. Methods We mapped the patterns of Material Loss in a series of 155 metal-on-metal total hip arthroplasties received at our center by scanning the taper surface using a roundness-measuring machine. We examined these Material Loss maps to develop a 5-tier classification system based on visual differences between different patterns. We correlated these patterns to surgical, implant, and patient factors known to be important for head-stem taper damage. Results We found that 63 implants had "minimal damage" at the taper (Material Loss 3 ), and the remaining 92 implants could be categorized by 4 distinct patterns of taper Material Loss. We found that (1) head diameter and (2) time to revision were key significant variables separating the groups. Conclusion These Material Loss maps allow us to suggest different mechanisms that dominate the cause of the Material Loss in each pattern: (1) corrosion, (2) mechanically assisted corrosion, or (3) intraoperative damage or poor size tolerances leading to toggling of trunnion in taper.
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influence of stem type on Material Loss at the metal on metal pinnacle taper junction
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART H-JOURNAL OF ENGINEERING IN MEDICINE 229 (1) pp. 91-97. (2015), 2015Co-Authors: Harry Hothi, Robert K Whittaker, J A Skinner, G W Blunn, Jay Meswania, Alister HartAbstract:The clinical importance of Material Loss at the head–stem junction is unknown. Comparison of retrievals with different stem types can provide the opportunity to understand the importance of the tap...
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the reliability of a scoring system for corrosion and fretting and its relationship to Material Loss of tapered modular junctions of retrieved hip implants
Journal of Arthroplasty, 2014Co-Authors: Harry Hothi, Robert K Whittaker, J A Skinner, Ashley K Matthies, Reshid Berber, Alister HartAbstract:Abstract It has been suggested that corrosion and fretting at the tapered, modular junctions of hip arthroplasties may contribute to implant failure. In this study the reliability of a commonly used peer-reviewed scoring system for visual assessment of corrosion and fretting at these junctions was evaluated. Volumetric Material Loss at the tapered head surface was measured and associations with the visual scores were investigated. We found that the inter-observer reproducibility and single-observer repeatability of the corrosion scores were substantial using Cohen's weighted Kappa statistic (k=0.64–0.71). The reproducibility and repeatability of the fretting scores however were slight to fair (k=0.18–0.31). Taper corrosion scores were significantly and moderately correlated with the volume of Material Loss measured (Spearman's r=0.59; P
J A Skinner - One of the best experts on this subject based on the ideXlab platform.
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variation in taper surface roughness for a single design effects the wear rate in total hip arthroplasty
Journal of Orthopaedic Research, 2017Co-Authors: Robert K Whittaker, Harry Hothi, J A Skinner, G W Blunn, Antti Eskelinen, A HartAbstract:Material Loss from the head-stem taper junction of total hip arthroplasty (THA) is implicated in adverse reactions to metal debris (ARMD); the mechanisms for this are multi-factorial. We investigated the relationship between the roughness of the "as manufactured" taper surface and the wear rate from this junction. Fifty retrieved Pinnacle metal-on-metal (MOM) bearings paired with a Corail stem were included in the study. Multivariable statistical analysis was performed to determine the influence of taper roughness on Material Loss rate after controlling for other confounding surgical, implant, and patient factors. The surface roughness of the "as manufactured" head taper surface was associated with the rate of Material Loss from this surface. Four of eighteen roughness variables taken from ISO 4,287 and ISO 13,565-2 were significant: The Reduced Peak Height (Rpk, the protruding peaks above the core) (p = 0.004), Material Ratio 1 (Mr1, the ratio of the protruding peaks above the core) (p = 0.002), Area of the Peak Region (A1, the area of the Abbott-Curve that contains the peaks from the profile) (p = 0.003) and the Skewness (Rsk, the asymmetry of the height distribution corresponding to the height or depth of surface features) (p = 0.03). We found a large variability in the measured values with a median (range) of 0.50 (0.05-2.98), 11.98 (0.46-39.98), 30.89 (0.15-581.00), and 0.04 (-0.73-0.84), respectively. A 1-unit increase in Rpk was associated with a 73% increase in the taper wear rate. The variability of "as manufactured" surface roughness has a significant effect on taper Material Loss. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
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damage patterns at the head stem taper junction helps understand the mechanisms of Material Loss
Journal of Arthroplasty, 2017Co-Authors: Harry Hothi, Andreas Panagiotopoulos, Robert K Whittaker, Paul J Bills, Rebecca A Mcmillan, J A Skinner, Alister HartAbstract:Abstract Background Material Loss at the taper junction of metal-on-metal total hip arthroplasties has been implicated in their early failure. The mechanisms of Material Loss are not fully understood; analysis of the patterns of damage at the taper can help us better understand why Material Loss occurs at this junction. Methods We mapped the patterns of Material Loss in a series of 155 metal-on-metal total hip arthroplasties received at our center by scanning the taper surface using a roundness-measuring machine. We examined these Material Loss maps to develop a 5-tier classification system based on visual differences between different patterns. We correlated these patterns to surgical, implant, and patient factors known to be important for head-stem taper damage. Results We found that 63 implants had "minimal damage" at the taper (Material Loss 3 ), and the remaining 92 implants could be categorized by 4 distinct patterns of taper Material Loss. We found that (1) head diameter and (2) time to revision were key significant variables separating the groups. Conclusion These Material Loss maps allow us to suggest different mechanisms that dominate the cause of the Material Loss in each pattern: (1) corrosion, (2) mechanically assisted corrosion, or (3) intraoperative damage or poor size tolerances leading to toggling of trunnion in taper.
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influence of stem type on Material Loss at the metal on metal pinnacle taper junction
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART H-JOURNAL OF ENGINEERING IN MEDICINE 229 (1) pp. 91-97. (2015), 2015Co-Authors: Harry Hothi, Robert K Whittaker, J A Skinner, G W Blunn, Jay Meswania, Alister HartAbstract:The clinical importance of Material Loss at the head–stem junction is unknown. Comparison of retrievals with different stem types can provide the opportunity to understand the importance of the tap...
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the reliability of a scoring system for corrosion and fretting and its relationship to Material Loss of tapered modular junctions of retrieved hip implants
Journal of Arthroplasty, 2014Co-Authors: Harry Hothi, Robert K Whittaker, J A Skinner, Ashley K Matthies, Reshid Berber, Alister HartAbstract:Abstract It has been suggested that corrosion and fretting at the tapered, modular junctions of hip arthroplasties may contribute to implant failure. In this study the reliability of a commonly used peer-reviewed scoring system for visual assessment of corrosion and fretting at these junctions was evaluated. Volumetric Material Loss at the tapered head surface was measured and associations with the visual scores were investigated. We found that the inter-observer reproducibility and single-observer repeatability of the corrosion scores were substantial using Cohen's weighted Kappa statistic (k=0.64–0.71). The reproducibility and repeatability of the fretting scores however were slight to fair (k=0.18–0.31). Taper corrosion scores were significantly and moderately correlated with the volume of Material Loss measured (Spearman's r=0.59; P