There are a variety of patient and surgical factors shown to increase post-operative complication... more There are a variety of patient and surgical factors shown to increase post-operative complication risk for a total hip arthroplasty (THA). While many studies have linked patient and surgical factors to unsuccessful outcomes post total hip arthroplasty (THA), no study has attempted to correlate the infiuence of these factors to the positioning of the acetabular cup. The purpose of this study was to determine if a correlation exists between patient and surgical factors and the anatomical position of the acetabular component. Data for 2063 patients from 2004–2008 who underwent a primary total hip arthroplasty (THA), revision THA, or Birmingham Hip Resurfacing procedure was compiled. The post- op anteroposterior pelvis (AP) and the cross table lateral digital radiographs for each patient were measured to determine cup inclination and version. Acceptable angle ranges were defined as 30–45° for abduction, and 5–25° for version. Correlations between variables and cup abduction and version ...
The development of highly cross-linked UHMWPEs focused on stabilizing radiation-induced free radi... more The development of highly cross-linked UHMWPEs focused on stabilizing radiation-induced free radicals as the sole precursor to oxidative degradation. However, secondary in vivo oxidation mechanisms have been discovered. After a preliminary post-operative analysis, we subjected highly cross-linked retrievals with 1-4years in vivo durations and never-implanted controls to accelerated aging to predict the extent to which their oxidative stability was compromised in vivo. Lipid absorption, oxidation, and hydroperoxides were measured using infrared spectroscopy. Gravimetric swelling was used to measure cross-link density. After aging, all retrievals, except vitamin E-stabilized components, regardless of initial lipid levels or oxidation, showed significant oxidative degradation, demonstrated by subsurface oxidative peaks, increased hydroperoxides and decreased cross-link density, compared to their post-operative material properties and never-implanted counterparts, confirming oxidative stability changes.
Objective. To study the risk factors for revision of primary total hip replacement (THR) in a US ... more Objective. To study the risk factors for revision of primary total hip replacement (THR) in a US population-based sample. Methods. Using Medicare claims, we identified beneficiaries from 29 US states who underwent primary THR between
Background: Management of periprosthetic femoral fractures is often complex, and few studies have... more Background: Management of periprosthetic femoral fractures is often complex, and few studies have documented its associated mortality. Methods: We retrospectively identified from our trauma and surgical registries 106 patients who underwent surgery for a periprosthetic femoral ...
Objectives-The aim of this case referent study was to investigate the relation between physical w... more Objectives-The aim of this case referent study was to investigate the relation between physical workload and osteoarthrosis of the hip in women. Methods-The study base comprised all women of ages 50-70 years, living in five counties and four towns in Sweden 1991-1994. Cases (n=230), who had undergone total hip replacement for primary osteoarthrosis of the hip were identified by means of the Swedish National Register of Total Hip Replacements, and the referents (n=273) were women without hip problems randomly selected from the study base. All women were interviewed about state of health, smoking habits, occupational history, work in the home, sports activities, etc. Each subject's history of occupational work and work in the home up to the age of 50 was divided into periods within each of which the work tasks were similar, and a questionnaire for each such period was filled in by the participants. On the basis of information given by the referents, the women were classified as having had low, medium, and high exposure to diVerent factors. Relative risks (RRs) and 95% confidence intervals (CI) were calculated. Results-Physically demanding tasks at work and in the home were associated with increased RRs of osteoarthrosis of the hip in those with high exposure compared with the low exposure group. A RR in the range of 2 or higher was found for those who frequently jumped or moved between diVerent levels (RR=2.1, CI 1.9, 4.2), who frequently climbed stairs (RR=2.1, CI 1.2, 3.6), and who had physically demanding tasks outside occupational life (RR=2.3, CI 1.5, 3.6). The highest RR (RR=4.3, CI 1.7, 11.0) was found for those exposed to high physical loads both at work and during sports activities. Conclusion-High physical loads at work and in the home up to the age of 50 seem to be risk factors for development of severe osteoarthrosis of the hip in women.
Background: A high quality decision requires that patients who meet clinical criteria for surgery... more Background: A high quality decision requires that patients who meet clinical criteria for surgery are informed about the options (including non-surgical alternatives) and receive treatments that match their goals. The aim of this study was to evaluate the psychometric properties and clinical sensibility of a patient self report instrument, to measure the quality of decisions about total joint replacement for knee or hip osteoarthritis. Methods: The performance of the Hip/Knee Osteoarthritis Decision Quality Instrument (HK-DQI) was evaluated in two samples: (1) a cross-sectional mail survey with 489 patients and 77 providers (study 1); and (2) a randomized controlled trial of a patient decision aid with 138 osteoarthritis patients considering total joint replacement (study 2). The HK-DQI results in two scores. Knowledge items are summed to create a total knowledge score, and a set of goals and concerns are used in a logistic regression model to develop a concordance score. The concordance score measures the proportion of patients whose treatment matched their goals. Hypotheses related to acceptability, feasibility, reliability and validity of the knowledge and concordance scores were examined. Results: In study 1, the HK-DQI was completed by 382 patients (79%) and 45 providers (58%), and in study 2 by 127 patients (92%), with low rates of missing data. The DQI-knowledge score was reproducible (ICC = 0.81) and demonstrated discriminant validity (68% decision aid vs. 54% control, and 78% providers vs. 61% patients) and content validity. The concordance score demonstrated predictive validity, as patients whose treatments were concordant with their goals had more confidence and less regret with their decision compared to those who did not. Conclusions: The HK-DQI is feasible and acceptable to patients. It can be used to assess whether patients with osteoarthritis are making informed decisions about surgery that are concordant with their goals.
Highly cross-linked polyethylene (PE) has been introduced as an alternative bearing material in t... more Highly cross-linked polyethylene (PE) has been introduced as an alternative bearing material in total hip arthroplasty (THA) because of high wear resistance in laboratory tests but the clinical experience of this material is limited. We evaluated a highly cross-linked PE (warm irradiated adiabatic melting, absorbed dose, 95 kGy) in a randomized study of cemented THAs. Cups of the same design but made of conventionally gamma irradiated PE (absorbed dose, 25-40 kGy) constituted the control group. Sixty-one hips (30 women, 30 men) with a median age of 55 years (range, 35-70 years) were included. All patients received a Spectron stem with 28-mm CoCr head. Radiostereometric examinations with the patient supine or standing were done at regular intervals. Wear was measured with the patient in the supine position from the first postoperative week, whereas examinations done with the patient standing were initiated 3 months after the operation. Dual x-ray absorptiometry and conventional radiography were used to evaluate the bone mineral density and the radiolucencies around the acetabular component. Fifty-two patients (53 hips; 25 highly cross-linked, 28 control) have been followed up for 2 years. At the 2-year followup, the highly cross-linked cups showed 50% reduction of proximal wear compared with the control group, when the patients were studied standing. When evaluated supine, the difference in proximal wear did not reach significance. The migration of the socket, the relative changes of periprosthetic bone mineral density, and the progression of radiolucencies between the immediately postoperative followup and 2-year followup did not differ. Highly cross-linked PE showed increase resistance to wear. Different mechanical properties of the two types of PE studied did not alter the performance of the cup in terms of fixation, periprosthetic bone loss, and radiographic appearance. However, the followup is short and these results are preliminary.
Background A 10-point Surgical Apgar Score, based on patients' estimated blood loss, lowest heart... more Background A 10-point Surgical Apgar Score, based on patients' estimated blood loss, lowest heart rate, and lowest mean arterial pressure during surgery, was developed to rate patients' outcomes in general and vascular surgery but has not been tested for patients having orthopaedic surgery. Questions/purposes For patients undergoing hip and knee arthroplasties, we asked (1) whether the score provides accurate risk stratification for major postoperative complications, and (2) whether it captures intraoperative
Background and purpose An earlier Nordic Arthroplasty Register Association (NARA) report on 280,2... more Background and purpose An earlier Nordic Arthroplasty Register Association (NARA) report on 280,201 total hip replacements (THRs) based on data from 1995-2006, from Sweden, Norway, and Denmark, was published in 2009. The present study assessed THR survival according to country, based on the NARA database with the Finnish data included. Material and methods 438,733 THRs performed during the period 1995-2011 in Sweden, Denmark, Norway, and Finland were included. Kaplan-Meier survival analysis was used to calculate survival probabilities with 95% confidence interval (CI). Cox multiple regression, with adjustment for age, sex, and diagnosis, was used to analyze implant survival with revision for any reason as endpoint. Results The 15-year survival, with any revision as an endpoint, for all THRs was 86% (CI: 85.7-86.9) in Denmark, 88% (CI: 87.6-88.3) in Sweden, 87% (CI: 86.4-87.4) in Norway, and 84% (CI: 82.9-84.1) in Finland. Revision risk for all THRs was less in Sweden than in the 3 other countries during the first 5 years. However, revision risk for uncemented THR was less in Denmark than in Sweden during the sixth (HR = 0.53, CI: 0.34-0.82), seventh (HR = 0.60, CI: 0.37-0.97), and ninth (HR = 0.59, CI: 0.36-0.98) year of follow-up. Interpretation The differences in THR survival rates were considerable, with inferior results in Finland. Brand-level comparison of THRs in Nordic countries will be required.
In Sweden, the number of arthroplasties increased by 20% from 8,336 in 1987 to 10,015 in 1997, an... more In Sweden, the number of arthroplasties increased by 20% from 8,336 in 1987 to 10,015 in 1997, an increase from 99 operations to 113 operations per 100,000 inhabitants (Figure 1). Only 3% of the increase in number of hip replacements could be explained by demographic changes in the population. The number of THA varied considerably each year. On the basis of the incidence of THA in 1997, the predicted annual number of THA in Sweden by the year 2020 will rise to 12,773 operations, an increase of 28% compared with 1997. When comparing the age of patients undergoing THA in the period 1986-1997, it turned out that in The Netherlands the distribution of the age-groups had changed relatively little, but in Sweden, more elderly people were operated on in 1997 (39% over 75 years of age) compared to 1987 (28% over 75 years of age) (Figure 2). Although the overall incidences of THA in 1997 were similar in both countries, it appears that the age-specific incidences for THA in women were higher in The Netherlands while the age-specific incidences for THA in men were higher in Sweden (Table). To correct for differences in the population profile (Figure 3), we calculated the number of total hip replacements in The Netherlands based on the Swedish incidence of THA in different age-classes. 4 (Figure 4). After correction for differences in population structure the rate of THA in The Netherlands is 20% higher than in Sweden.
The choice of optimal implant fixation in total hip replacement (THR)--fixation with or without c... more The choice of optimal implant fixation in total hip replacement (THR)--fixation with or without cement--has been the subject of much debate. We performed a systematic review and meta-analysis of the published literature comparing cemented and uncemented fixation in THR. No advantage was found for either procedure when failure was defined as either: (A) revision of either or both components, or (B) revision of a specific component. No difference was seen between estimates from registry and single-center studies, or between randomized and non-randomized studies. Subgroup analysis of type A studies showed superior survival with cemented fixation in studies including patients of all ages as compared to those that only studied patients 55 years of age or younger. Among type B studies, cemented titanium stems and threaded cups were associated with poor survival. An association was found between difference in survival and year of publication, with uncemented fixation showing relative superiority over time. While the recent literature suggests that the performance of uncemented implants is improving, cemented fixation continues to outperform uncemented fixation in large subsets of study populations. Our findings summarize the best available evidence qualitatively and quantitatively and provide important information for future research.
A higher cobalt/chromium (Co/Cr) ratio is thought to be associated with corrosion of the trunnion... more A higher cobalt/chromium (Co/Cr) ratio is thought to be associated with corrosion of the trunnion and increased adverse local tissue reaction (ALTR) risk in patients treated with metal-on-metal (MoM) hip arthroplasty. The main aim of this study was to investigate the diagnostic value of Co/Cr ratio in identifying ALTR in patients treated with MoM hip resurfacing arthroplasty and total hip arthroplasty (THA). A total of 310 unilateral patients were included. All patients received a metal artifact reduction sequence magnetic resonance imaging to detect ALTR. Blood Co and Cr levels were measured. MoM THA patients had a higher Co/Cr ratio than MoM hip resurfacing arthroplasty patients (1.7, interquartile range 1.2-3.1 vs 0.9, interquartile range 0.7-1.3, P < .001). The continuous Co/Cr ratio, continuous Co, and Co ≥ 7 ppb were predictive of ALTR when tested in receiver-operating characteristic analyses. The most sensitive and specific cutoffs were found to be 1.4 for Co/Cr ratio (sen...
Hip international : the journal of clinical and experimental research on hip pathology and therapy, 2018
Periprosthetic joint infection (PJI) is a serious complication after total hip arthroplasty (THA)... more Periprosthetic joint infection (PJI) is a serious complication after total hip arthroplasty (THA) and bearing material's associations to PJI prevalence is largely unknown. The main purposes of this study were to determine if revision for infection varied depending on the type of bearing surface used in primary THA and to study whether patient or implant related factors had an effect on this variation. A total of 177,237 primary THA procedures from the Australian Registry (AOANJRR) were analysed. 3 bearing surfaces were compared. Metal-on-highly cross-linked polyethylene (MoXP) bearing had been used in 95,129 hips, ceramic-on-highly cross-linked polyethylene (CoXP) in 24,269 hips, and ceramic-on-ceramic (CoC) in 57,839 hips. Revision rates for infection were compared between the 3 groups. Both MoXP and CoXP had a higher revision rate for infection compared to CoC hips (hazard ratio [HR] 1.46 (1.25, 1.72), p < 0.001) and HR 1.42 (1.15, 1.75), p = 0.001 respectively). Patients a...
Hip international : the journal of clinical and experimental research on hip pathology and therapy, 2018
The primary aim of the current study was to determine whether metal ion levels could identify wel... more The primary aim of the current study was to determine whether metal ion levels could identify well- from poorly-functioning implants in patients after undergoing bilateral Articular Surface Replacement (ASR) Hip System. The secondary aim was to establish threshold values for Co and Cr that could be used to predict clinical problems in these patients. The study included 125 patients treated with bilateral ASR hip resurfacing (HRA) and 93 patients treated with bilateral ASR XL total hip arthroplasty (THA) at a mean follow-up of 7.1 years post-surgery. Patients were labelled as well- or poorly-functioning based on strict criteria. We calculated the Co and Cr safe upper ion limits (SUL) for ASR HRA and ASR XL THA separately and assessed these cutoffs ability to predict clinical problems. In patients with bilateral ASR HRA, the well-functioning group had lower ions than the poorly-functioning. In ASR THA patients, there was no difference in blood Co or Cr levels between well- and poorly-...
There are a variety of patient and surgical factors shown to increase post-operative complication... more There are a variety of patient and surgical factors shown to increase post-operative complication risk for a total hip arthroplasty (THA). While many studies have linked patient and surgical factors to unsuccessful outcomes post total hip arthroplasty (THA), no study has attempted to correlate the infiuence of these factors to the positioning of the acetabular cup. The purpose of this study was to determine if a correlation exists between patient and surgical factors and the anatomical position of the acetabular component. Data for 2063 patients from 2004–2008 who underwent a primary total hip arthroplasty (THA), revision THA, or Birmingham Hip Resurfacing procedure was compiled. The post- op anteroposterior pelvis (AP) and the cross table lateral digital radiographs for each patient were measured to determine cup inclination and version. Acceptable angle ranges were defined as 30–45° for abduction, and 5–25° for version. Correlations between variables and cup abduction and version ...
The development of highly cross-linked UHMWPEs focused on stabilizing radiation-induced free radi... more The development of highly cross-linked UHMWPEs focused on stabilizing radiation-induced free radicals as the sole precursor to oxidative degradation. However, secondary in vivo oxidation mechanisms have been discovered. After a preliminary post-operative analysis, we subjected highly cross-linked retrievals with 1-4years in vivo durations and never-implanted controls to accelerated aging to predict the extent to which their oxidative stability was compromised in vivo. Lipid absorption, oxidation, and hydroperoxides were measured using infrared spectroscopy. Gravimetric swelling was used to measure cross-link density. After aging, all retrievals, except vitamin E-stabilized components, regardless of initial lipid levels or oxidation, showed significant oxidative degradation, demonstrated by subsurface oxidative peaks, increased hydroperoxides and decreased cross-link density, compared to their post-operative material properties and never-implanted counterparts, confirming oxidative stability changes.
Objective. To study the risk factors for revision of primary total hip replacement (THR) in a US ... more Objective. To study the risk factors for revision of primary total hip replacement (THR) in a US population-based sample. Methods. Using Medicare claims, we identified beneficiaries from 29 US states who underwent primary THR between
Background: Management of periprosthetic femoral fractures is often complex, and few studies have... more Background: Management of periprosthetic femoral fractures is often complex, and few studies have documented its associated mortality. Methods: We retrospectively identified from our trauma and surgical registries 106 patients who underwent surgery for a periprosthetic femoral ...
Objectives-The aim of this case referent study was to investigate the relation between physical w... more Objectives-The aim of this case referent study was to investigate the relation between physical workload and osteoarthrosis of the hip in women. Methods-The study base comprised all women of ages 50-70 years, living in five counties and four towns in Sweden 1991-1994. Cases (n=230), who had undergone total hip replacement for primary osteoarthrosis of the hip were identified by means of the Swedish National Register of Total Hip Replacements, and the referents (n=273) were women without hip problems randomly selected from the study base. All women were interviewed about state of health, smoking habits, occupational history, work in the home, sports activities, etc. Each subject's history of occupational work and work in the home up to the age of 50 was divided into periods within each of which the work tasks were similar, and a questionnaire for each such period was filled in by the participants. On the basis of information given by the referents, the women were classified as having had low, medium, and high exposure to diVerent factors. Relative risks (RRs) and 95% confidence intervals (CI) were calculated. Results-Physically demanding tasks at work and in the home were associated with increased RRs of osteoarthrosis of the hip in those with high exposure compared with the low exposure group. A RR in the range of 2 or higher was found for those who frequently jumped or moved between diVerent levels (RR=2.1, CI 1.9, 4.2), who frequently climbed stairs (RR=2.1, CI 1.2, 3.6), and who had physically demanding tasks outside occupational life (RR=2.3, CI 1.5, 3.6). The highest RR (RR=4.3, CI 1.7, 11.0) was found for those exposed to high physical loads both at work and during sports activities. Conclusion-High physical loads at work and in the home up to the age of 50 seem to be risk factors for development of severe osteoarthrosis of the hip in women.
Background: A high quality decision requires that patients who meet clinical criteria for surgery... more Background: A high quality decision requires that patients who meet clinical criteria for surgery are informed about the options (including non-surgical alternatives) and receive treatments that match their goals. The aim of this study was to evaluate the psychometric properties and clinical sensibility of a patient self report instrument, to measure the quality of decisions about total joint replacement for knee or hip osteoarthritis. Methods: The performance of the Hip/Knee Osteoarthritis Decision Quality Instrument (HK-DQI) was evaluated in two samples: (1) a cross-sectional mail survey with 489 patients and 77 providers (study 1); and (2) a randomized controlled trial of a patient decision aid with 138 osteoarthritis patients considering total joint replacement (study 2). The HK-DQI results in two scores. Knowledge items are summed to create a total knowledge score, and a set of goals and concerns are used in a logistic regression model to develop a concordance score. The concordance score measures the proportion of patients whose treatment matched their goals. Hypotheses related to acceptability, feasibility, reliability and validity of the knowledge and concordance scores were examined. Results: In study 1, the HK-DQI was completed by 382 patients (79%) and 45 providers (58%), and in study 2 by 127 patients (92%), with low rates of missing data. The DQI-knowledge score was reproducible (ICC = 0.81) and demonstrated discriminant validity (68% decision aid vs. 54% control, and 78% providers vs. 61% patients) and content validity. The concordance score demonstrated predictive validity, as patients whose treatments were concordant with their goals had more confidence and less regret with their decision compared to those who did not. Conclusions: The HK-DQI is feasible and acceptable to patients. It can be used to assess whether patients with osteoarthritis are making informed decisions about surgery that are concordant with their goals.
Highly cross-linked polyethylene (PE) has been introduced as an alternative bearing material in t... more Highly cross-linked polyethylene (PE) has been introduced as an alternative bearing material in total hip arthroplasty (THA) because of high wear resistance in laboratory tests but the clinical experience of this material is limited. We evaluated a highly cross-linked PE (warm irradiated adiabatic melting, absorbed dose, 95 kGy) in a randomized study of cemented THAs. Cups of the same design but made of conventionally gamma irradiated PE (absorbed dose, 25-40 kGy) constituted the control group. Sixty-one hips (30 women, 30 men) with a median age of 55 years (range, 35-70 years) were included. All patients received a Spectron stem with 28-mm CoCr head. Radiostereometric examinations with the patient supine or standing were done at regular intervals. Wear was measured with the patient in the supine position from the first postoperative week, whereas examinations done with the patient standing were initiated 3 months after the operation. Dual x-ray absorptiometry and conventional radiography were used to evaluate the bone mineral density and the radiolucencies around the acetabular component. Fifty-two patients (53 hips; 25 highly cross-linked, 28 control) have been followed up for 2 years. At the 2-year followup, the highly cross-linked cups showed 50% reduction of proximal wear compared with the control group, when the patients were studied standing. When evaluated supine, the difference in proximal wear did not reach significance. The migration of the socket, the relative changes of periprosthetic bone mineral density, and the progression of radiolucencies between the immediately postoperative followup and 2-year followup did not differ. Highly cross-linked PE showed increase resistance to wear. Different mechanical properties of the two types of PE studied did not alter the performance of the cup in terms of fixation, periprosthetic bone loss, and radiographic appearance. However, the followup is short and these results are preliminary.
Background A 10-point Surgical Apgar Score, based on patients' estimated blood loss, lowest heart... more Background A 10-point Surgical Apgar Score, based on patients' estimated blood loss, lowest heart rate, and lowest mean arterial pressure during surgery, was developed to rate patients' outcomes in general and vascular surgery but has not been tested for patients having orthopaedic surgery. Questions/purposes For patients undergoing hip and knee arthroplasties, we asked (1) whether the score provides accurate risk stratification for major postoperative complications, and (2) whether it captures intraoperative
Background and purpose An earlier Nordic Arthroplasty Register Association (NARA) report on 280,2... more Background and purpose An earlier Nordic Arthroplasty Register Association (NARA) report on 280,201 total hip replacements (THRs) based on data from 1995-2006, from Sweden, Norway, and Denmark, was published in 2009. The present study assessed THR survival according to country, based on the NARA database with the Finnish data included. Material and methods 438,733 THRs performed during the period 1995-2011 in Sweden, Denmark, Norway, and Finland were included. Kaplan-Meier survival analysis was used to calculate survival probabilities with 95% confidence interval (CI). Cox multiple regression, with adjustment for age, sex, and diagnosis, was used to analyze implant survival with revision for any reason as endpoint. Results The 15-year survival, with any revision as an endpoint, for all THRs was 86% (CI: 85.7-86.9) in Denmark, 88% (CI: 87.6-88.3) in Sweden, 87% (CI: 86.4-87.4) in Norway, and 84% (CI: 82.9-84.1) in Finland. Revision risk for all THRs was less in Sweden than in the 3 other countries during the first 5 years. However, revision risk for uncemented THR was less in Denmark than in Sweden during the sixth (HR = 0.53, CI: 0.34-0.82), seventh (HR = 0.60, CI: 0.37-0.97), and ninth (HR = 0.59, CI: 0.36-0.98) year of follow-up. Interpretation The differences in THR survival rates were considerable, with inferior results in Finland. Brand-level comparison of THRs in Nordic countries will be required.
In Sweden, the number of arthroplasties increased by 20% from 8,336 in 1987 to 10,015 in 1997, an... more In Sweden, the number of arthroplasties increased by 20% from 8,336 in 1987 to 10,015 in 1997, an increase from 99 operations to 113 operations per 100,000 inhabitants (Figure 1). Only 3% of the increase in number of hip replacements could be explained by demographic changes in the population. The number of THA varied considerably each year. On the basis of the incidence of THA in 1997, the predicted annual number of THA in Sweden by the year 2020 will rise to 12,773 operations, an increase of 28% compared with 1997. When comparing the age of patients undergoing THA in the period 1986-1997, it turned out that in The Netherlands the distribution of the age-groups had changed relatively little, but in Sweden, more elderly people were operated on in 1997 (39% over 75 years of age) compared to 1987 (28% over 75 years of age) (Figure 2). Although the overall incidences of THA in 1997 were similar in both countries, it appears that the age-specific incidences for THA in women were higher in The Netherlands while the age-specific incidences for THA in men were higher in Sweden (Table). To correct for differences in the population profile (Figure 3), we calculated the number of total hip replacements in The Netherlands based on the Swedish incidence of THA in different age-classes. 4 (Figure 4). After correction for differences in population structure the rate of THA in The Netherlands is 20% higher than in Sweden.
The choice of optimal implant fixation in total hip replacement (THR)--fixation with or without c... more The choice of optimal implant fixation in total hip replacement (THR)--fixation with or without cement--has been the subject of much debate. We performed a systematic review and meta-analysis of the published literature comparing cemented and uncemented fixation in THR. No advantage was found for either procedure when failure was defined as either: (A) revision of either or both components, or (B) revision of a specific component. No difference was seen between estimates from registry and single-center studies, or between randomized and non-randomized studies. Subgroup analysis of type A studies showed superior survival with cemented fixation in studies including patients of all ages as compared to those that only studied patients 55 years of age or younger. Among type B studies, cemented titanium stems and threaded cups were associated with poor survival. An association was found between difference in survival and year of publication, with uncemented fixation showing relative superiority over time. While the recent literature suggests that the performance of uncemented implants is improving, cemented fixation continues to outperform uncemented fixation in large subsets of study populations. Our findings summarize the best available evidence qualitatively and quantitatively and provide important information for future research.
A higher cobalt/chromium (Co/Cr) ratio is thought to be associated with corrosion of the trunnion... more A higher cobalt/chromium (Co/Cr) ratio is thought to be associated with corrosion of the trunnion and increased adverse local tissue reaction (ALTR) risk in patients treated with metal-on-metal (MoM) hip arthroplasty. The main aim of this study was to investigate the diagnostic value of Co/Cr ratio in identifying ALTR in patients treated with MoM hip resurfacing arthroplasty and total hip arthroplasty (THA). A total of 310 unilateral patients were included. All patients received a metal artifact reduction sequence magnetic resonance imaging to detect ALTR. Blood Co and Cr levels were measured. MoM THA patients had a higher Co/Cr ratio than MoM hip resurfacing arthroplasty patients (1.7, interquartile range 1.2-3.1 vs 0.9, interquartile range 0.7-1.3, P < .001). The continuous Co/Cr ratio, continuous Co, and Co ≥ 7 ppb were predictive of ALTR when tested in receiver-operating characteristic analyses. The most sensitive and specific cutoffs were found to be 1.4 for Co/Cr ratio (sen...
Hip international : the journal of clinical and experimental research on hip pathology and therapy, 2018
Periprosthetic joint infection (PJI) is a serious complication after total hip arthroplasty (THA)... more Periprosthetic joint infection (PJI) is a serious complication after total hip arthroplasty (THA) and bearing material's associations to PJI prevalence is largely unknown. The main purposes of this study were to determine if revision for infection varied depending on the type of bearing surface used in primary THA and to study whether patient or implant related factors had an effect on this variation. A total of 177,237 primary THA procedures from the Australian Registry (AOANJRR) were analysed. 3 bearing surfaces were compared. Metal-on-highly cross-linked polyethylene (MoXP) bearing had been used in 95,129 hips, ceramic-on-highly cross-linked polyethylene (CoXP) in 24,269 hips, and ceramic-on-ceramic (CoC) in 57,839 hips. Revision rates for infection were compared between the 3 groups. Both MoXP and CoXP had a higher revision rate for infection compared to CoC hips (hazard ratio [HR] 1.46 (1.25, 1.72), p < 0.001) and HR 1.42 (1.15, 1.75), p = 0.001 respectively). Patients a...
Hip international : the journal of clinical and experimental research on hip pathology and therapy, 2018
The primary aim of the current study was to determine whether metal ion levels could identify wel... more The primary aim of the current study was to determine whether metal ion levels could identify well- from poorly-functioning implants in patients after undergoing bilateral Articular Surface Replacement (ASR) Hip System. The secondary aim was to establish threshold values for Co and Cr that could be used to predict clinical problems in these patients. The study included 125 patients treated with bilateral ASR hip resurfacing (HRA) and 93 patients treated with bilateral ASR XL total hip arthroplasty (THA) at a mean follow-up of 7.1 years post-surgery. Patients were labelled as well- or poorly-functioning based on strict criteria. We calculated the Co and Cr safe upper ion limits (SUL) for ASR HRA and ASR XL THA separately and assessed these cutoffs ability to predict clinical problems. In patients with bilateral ASR HRA, the well-functioning group had lower ions than the poorly-functioning. In ASR THA patients, there was no difference in blood Co or Cr levels between well- and poorly-...
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Papers by Henrik Malchau