Zeitschrift für Orthopädie und Unfallchirurgie, 2019
Background and study aim Elderly individuals are the most rapidly growing subgroup of patients cu... more Background and study aim Elderly individuals are the most rapidly growing subgroup of patients currently sustaining acetabular fractures, and total hip arthroplasty (THA) is being applied more and more in the treatment of acetabular fractures. The purpose of this study was to review the available literature regarding displaced acetabular fractures in elderly patients treated with acute THA. Study design A search was conducted using the electronic databases Medline, PubMed, ISI Web of Knowledge, and Scopus on papers published between January 1960 and November 2018 using the terms “acetabular fracture” plus “elderly patients” plus “arthroplasty”. A systematic review of the literature on the different treatment options for acute THA is presented. Results The search yielded a total of 320 articles, and 9 articles were selected for review. The indications, techniques, approaches, and complications of THA are discussed, and a treatment recommendation based on the selected articles is give...
The consequences of hip disorders and hip injuries in children and adolescents may require surgic... more The consequences of hip disorders and hip injuries in children and adolescents may require surgical intervention. Joint-preserving procedures performed between the ages of 12 and 21 years often give good long-term results and may postpone the need for prostheses. In patients aged less than 21 years, more than 90 % of modern hip prostheses implanted in the last two decades are intact after ten years.
Aims Medial pivot (MP) total knee arthroplasties (TKAs) were designed to mimic native knee kinema... more Aims Medial pivot (MP) total knee arthroplasties (TKAs) were designed to mimic native knee kinematics with their deep medial congruent fitting of the tibia to the femur almost like a ball-on-socket, and a flat lateral part. GMK Sphere is a novel MP implant. Our primary aim was to study the migration pattern of the tibial tray of this TKA. Methods A total of 31 patients were recruited to this single-group radiostereometric analysis (RSA) study and received a medial pivot GMK Sphere TKA. The distributions of male patients versus female patients and right versus left knees were 21:10 and 17:14, respectively. Mean BMI was 29 kg/m2 (95% confidence interval (CI) 27 to 30) and mean age at surgery was 63 years (95% CI 61 to 66). Maximum total point motions (MTPMs), medial, proximal, and anterior translations and transversal, internal, and varus rotations were calculated at three, 12, and 24 months. Patient-reported outcome measure data were also retrieved. Results MTPMs at three, 12, and 24...
Background and purpose - There is some concern regarding the revision rate of the Vanguard CR TKA... more Background and purpose - There is some concern regarding the revision rate of the Vanguard CR TKA in 1 registry, and the literature is ambiguous about the efficacy of patient-specific positioning guides (PSPGs). The objective of this study was to investigate the stability of the cemented Vanguard CR Total Knee using 2 different surgical techniques. Our hypothesis was that there is no difference in migration when implanting the Vanguard CR with either PSPGs or conventional technique. We hereby present a randomized controlled trial of 2-year follow-up with radiostereometric analysis (RSA). Patients and methods - 40 TKAs were performed between 2011 and 2013 with either PSPGs or the conventional technique and 22 of these were investigated with RSA. Results - The PSPG (8 knees) and the conventional (14 knees) groups had a mean maximum total point motion (MTPM) (95% CI) of 0.83 (0.48-1.18) vs. 0.70 (0.43-0.97) mm, 1.03 (0.60-1.43) vs. 0.86 (0.53-1.19), and 1.46 (1.07-1.85) vs. 0.80 (0.52-...
Background and purpose - Although the use of patient-specific positioning guides (PSPGs) in total... more Background and purpose - Although the use of patient-specific positioning guides (PSPGs) in total knee replacement (TKR) in theory is promising, the technique has not yet proven its superior- ity compared with the conventional method. We compared radio- logical alignment and clinical outcome between TKR performed with the use of PSPGs and the conventional operation method. Patients and methods - 3 hospitals participated in a prospec- tive trial. 109 patients were randomized to either the conventional method or to the use of PSPGs. Postoperatively a full-length standing anteroposterior radiograph and a postoperative CT scan were taken. On the CT scan the alignments were measured for both the femoral and tibial components in the frontal, sagit- tal, and axial plane. The Knee injury and Osteoarthritis Outcome Score (KOOS), the Eurocol-5D-3L (Eq5D) descriptive system and visual analogue scale (VAS), a pain score (NRS), and range of motion (ROM) were recorded preoperatively, and at 3 mon...
The effect of patellar eversion on ligament laxity measurements is still unclear. The purpose of ... more The effect of patellar eversion on ligament laxity measurements is still unclear. The purpose of this study was to investigate the influence of patellar eversion on medial and lateral ligament laxity measurements performed intra-operatively in total knee arthroplasty (TKA). A total of 49 knees (27 female) with mean age 70 years (42-83) and mean body mass index of 28.5 were operated consecutively with a cruciate-retaining prosthesis. Medial and lateral ligament laxity in extension and in 90° of flexion was measured with the spatula-method intra-operatively after implantation of the prosthetic components with the patella everted and thereafter with the patella repositioned. The corresponding changes in gap height and inclination were calculated. A statistically significant increase of 0.6 mm (p < 0.001) in ligament laxity (condylar lift-off) laterally in flexion was found with the patella repositioned compared to everted. No differences were found in extension or medially in flexion. Correspondingly, the flexion gap increased by 0.4 mm (p < 0.001) and the flexion gap inclination increased by 0.6° (p = 0.002) when the patella was repositioned. Earlier research has shown that ligament laxity must be at least 1-2 mm to cause inferior function after TKA. In the current study, we found that the effect of patellar eversion on ligament laxity measurements is too small to be considered clinically relevant. PROSPECTIVE STUDY EVALUATING THE EFFECT OF PATIENT CHARACTERISTICS: Level II.
The Active Straight Leg Raise is a functional test used in the assessment of pelvic girdle pain, ... more The Active Straight Leg Raise is a functional test used in the assessment of pelvic girdle pain, and has shown to have good validity, reliability and responsiveness. The Active Straight Leg Raise is considered to examine the patients' ability to transfer load through the pelvis. It has been hypothesized that patients with pelvic girdle pain lack the ability to stabilize the pelvic girdle, probably due to instability or increased movement of the sacroiliac joint. This study examines the movement of the sacroiliac joints during the Active Straight Leg Raise in patients with pelvic girdle pain. Tantalum markers were inserted in the dorsal sacrum and ilium of 12 patients with long-lasting pelvic girdle pain scheduled for sacroiliac joint fusion surgery. Two to three weeks later movement of the sacroiliac joints during the Active Straight Leg Raise was measured with radiostereometric analysis. Small movements were detected. There was larger movement of the sacroiliac joint of the rested leg's sacroiliac joint compared to the lifted leg's side. A mean backward rotation of 0.8° and inward tilt of 0.3° were seen in the rested leg's sacroiliac joint. The movements of the sacroiliac joints during the Active Straight Leg Raise are small. There was a small backward rotation of the innominate bone relative to sacrum on the rested leg's side. Our findings contradict an earlier understanding that a forward rotation of the lifted leg's innominate occur while performing the Active Straight Leg Raise.
Hip international : the journal of clinical and experimental research on hip pathology and therapy, Jan 2, 2016
Cartilage wear is a concern after hemiarthroplasty. The precise pattern of the progression of wea... more Cartilage wear is a concern after hemiarthroplasty. The precise pattern of the progression of wear has not been evaluated. We previously reported the application of radiostereonetric analysis (RSA) for the measurement of cartilage wear in patients. The purpose of this study was to report the amount and the orientation of the steady state wear of cartilage between 1 and 3 years after bipolar hemiarthroplasty. 22 patients with a bipolar hemiarthroplasty for displaced femoral neck fracture were included. 10 patients completed the mean follow up of 37 months. The cartilage wear was evaluated by calculating the migration of the bipolar head in reference to the markers in the acetabulum using RSA. The mean age of the patients at the final follow-up was 80 (range 67-91) years. The 3-D migration was -0.02 mm (SD 0.30) between 1 and 3 years. The migration in each direction was 0.03 mm (SD 0.49) in medial, 0.03 mm (SD 0.14) in proximal and 0.11 mm (SD 0.29) in posterior directions. 2 patients...
Background and purpose - Computer-assisted surgery (CAS) in total knee arthroplasty (TKA) has bee... more Background and purpose - Computer-assisted surgery (CAS) in total knee arthroplasty (TKA) has been used in recent years in the hope of improving the alignment and positioning of the implant, thereby achieving a better functional outcome and durability. However, the role of computer navigation in TKA is still under debate. We used radiostereometric analysis (RSA) in a randomized controlled trial (RCT) to determine whether there are any differences in migration of the tibial component between CAS- and conventionally (CONV-) operated TKA. Patients and methods - 54 patients (CAS, n = 26; CONV, n = 28) with a mean age of 67 (56-78) years and with osteoarthritis or arthritic disease of the knee were recruited from 4 hospitals during the period 2009-2011. To estimate the mechanical stability of the tibial component, the patients were examined with RSA up to 24 months after operation. The following parameters representing tibial component micromotion were measured: 3-D vector of the prosthe...
Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA, Jan 12, 2016
To investigate whether the intended preoperative planning corresponded with the postoperative com... more To investigate whether the intended preoperative planning corresponded with the postoperative component position after medial UKA using patient-specific positioning guides (PSPGs). Twenty-five consecutive UKAs performed with the PSPG technique (Signature™) were included. Two independent observers performed postoperative CT measurements. The preoperative angles for the femoral component were defined in the frontal plane as 0°. In the first eight cases, a femoral component with single peg was inserted, and the flexion of the femoral component was set to 5°. In the last 17 cases, a twin-peg component was used and flexion set to 10°. In the axial plane, the femoral component was on average set at 2.5° internal rotation. The preoperative tibial component angles in the frontal and axial plane were defined as 0° and in the sagittal plane as 4° in flexion. The postoperative femoral component angles were on average 0.8° of valgus (SD 3.2, range 12.2° valgus to 5.1° varus, n.s., CI -2.1 to 0....
Elementary geometrical shape (EGS) models are useful in radiostereometric analysis (RSA) on hip s... more Elementary geometrical shape (EGS) models are useful in radiostereometric analysis (RSA) on hip stems because tantalum markers attached to the stems can be omitted. In order to create an EGS model of a femoral stem, the center of the femoral head has to be identified. The contour of the femoral head is recommended to be used. However, the contour of the femoral head cannot be detected exclusively by computer if it is combined with a bipolar head or a metal cup. We therefore hypothesized that the contour of the outer head of bipolar hemiarthroplasty can be included in the EGS model as well as the femoral head contour. We calculated the time required for the detection of the contour, the precision of analysis and the stem micromotion at 2 years using the two different methods in the same picture set and compared the results. The detection of the bipolar head contour was 10 times faster than that of the femoral head contour. The precision for subsidence was 0.16mm in EGS RSA with the femoral head contour, and 0.15mm with the bipolar head contour (p=0.68). The precisions were comparable and clinically acceptable. There was no significant difference between the results of the 2-year micromotion with the two different methods. We conclude that this new method is applicable to measure stem micromotion of hemi-arthoplasty with EGS RSA and the method facilitates the Radiostereometric analysis.
Journal of Bone Joint Surgery British Volume, Sep 1, 2012
Background Tranexamic acid (TA) in total knee replacement surgery (TKR) has shown marked reductio... more Background Tranexamic acid (TA) in total knee replacement surgery (TKR) has shown marked reduction in bleeding and blood transfusion. There are little data on TA in revision TKR. From February 2008 all patients having primary or revision TKR received TA 10mg/kg × 2. We whished to evaluate the effect and possible complications of TA. Patients and Methods 49 patients had revision TKR from January to August 2010. 21 patients (group I) operated before the regular use of TA were compared to 28 patients (group II) receiving TA. The groups were compared according to bleeding, blood transfusion, postoperative complication and type of revision. Revision TKR was compared to 157 primary TKR (94 operated without TA (group III) and 63 who received TA (group IV). Results Group I: Preoperative Hgl 13.6g/dl (9.2–15.3), reduction in hgl 3.9g/dl (1.0–5.7), bleeding 1040ml (380–2100). 6 patients (28.6%) needed blood transfusion. 7 patients were admitted to cell-saver and were given mean 400 ml blood (150–730). There were 6 revisions from uni-prostheses to TKR and 15 was revision of TKR. There was no difference in bleeding between this to groups (980ml/1030ml). Group II: Preoperative Hgl 14.2g/dl (11.2–18.6), reduction in hgl 3.3g/dl (1.4–8.3), bleeding 490ml (120–1050) (47.1% reduction in bleeding volume (p There was 8 revisions from uni-prostheses to TKR and 21 was revision of TKR. There was no difference in bleeding between this two groups (510ml/570ml). Group III: Preoperative Hgl 14.2g/dl (10.1–17.4), reduction in Hgl 3.5g/dl (1.1–7.7), bleeding 1048ml (50–2230). 15 patients (16%) needed blood transfusion. Group IV: Preoperative Hgl 13.7g/dl (11.6–18.1), reduction in Hgl 2.76g/dl (1.2–4.8) (p=0,014), bleeding 370ml (130–960) (64.5% reduction in volume (p There was no statistically significant difference in bleeding between primary and revision TKR (p=0.18). Conclusion Our results shows that TA reduces bleeding and the need for blood transfusion markedly. The TA groups had no increase in any complications.
Screws, pegs and hydroxyapatite-coating are used to enhance the primary stability of uncemented c... more Screws, pegs and hydroxyapatite-coating are used to enhance the primary stability of uncemented cups. We present a 14-year follow-up of 48 hips randomized to four groups: press-fit only, press-fit plus screws, press-fit plus pegs and hydroxyapatite-coated cups. Radiostereometric migration measurements showed equally good stability regardless cup augmentation. The mean wear rate was high, 0.21mm/year, with no differences between the groups. Seven hips had radiographical osteolysis but only in hips with augmented cups. Cups without screw-holes compared with cups with screw-holes resulted in better clinical outcome at the 14-year follow-up. Thus, augmentation of uncemented cups with screws, pegs, or hydroxyapatite did not appear to improve the long-term stability compared with press-fit only.
Background and purpose - There have been few comparative studies on total knee replacement (TKR) ... more Background and purpose - There have been few comparative studies on total knee replacement (TKR) with cemented tibia and uncemented femur (hybrid TKR). Previous studies have not shown any difference in revision rate between cemented and hybrid fixation, but these studies had few hybrid prostheses. We have evaluated the outcome of hybrid TKR based on data from the Norwegian Arthroplasty Register (NAR). Patients and methods - We compared 4,585 hybrid TKRs to 20,095 cemented TKRs with risk of revision for any cause as the primary endpoint. We included primary TKRs without patella resurfacing that were reported to the NAR during the years 1999-2012. To minimize the possible confounding effect of prosthesis brands, only brands that were used both as hybrids and cemented in more than 200 cases were included. Kaplan-Meier survival analysis and Cox regression analysis were done with adjustment for age, sex, and preoperative diagnosis. To include death as a competing risk, cumulative inciden...
Zeitschrift für Orthopädie und Unfallchirurgie, 2019
Background and study aim Elderly individuals are the most rapidly growing subgroup of patients cu... more Background and study aim Elderly individuals are the most rapidly growing subgroup of patients currently sustaining acetabular fractures, and total hip arthroplasty (THA) is being applied more and more in the treatment of acetabular fractures. The purpose of this study was to review the available literature regarding displaced acetabular fractures in elderly patients treated with acute THA. Study design A search was conducted using the electronic databases Medline, PubMed, ISI Web of Knowledge, and Scopus on papers published between January 1960 and November 2018 using the terms “acetabular fracture” plus “elderly patients” plus “arthroplasty”. A systematic review of the literature on the different treatment options for acute THA is presented. Results The search yielded a total of 320 articles, and 9 articles were selected for review. The indications, techniques, approaches, and complications of THA are discussed, and a treatment recommendation based on the selected articles is give...
The consequences of hip disorders and hip injuries in children and adolescents may require surgic... more The consequences of hip disorders and hip injuries in children and adolescents may require surgical intervention. Joint-preserving procedures performed between the ages of 12 and 21 years often give good long-term results and may postpone the need for prostheses. In patients aged less than 21 years, more than 90 % of modern hip prostheses implanted in the last two decades are intact after ten years.
Aims Medial pivot (MP) total knee arthroplasties (TKAs) were designed to mimic native knee kinema... more Aims Medial pivot (MP) total knee arthroplasties (TKAs) were designed to mimic native knee kinematics with their deep medial congruent fitting of the tibia to the femur almost like a ball-on-socket, and a flat lateral part. GMK Sphere is a novel MP implant. Our primary aim was to study the migration pattern of the tibial tray of this TKA. Methods A total of 31 patients were recruited to this single-group radiostereometric analysis (RSA) study and received a medial pivot GMK Sphere TKA. The distributions of male patients versus female patients and right versus left knees were 21:10 and 17:14, respectively. Mean BMI was 29 kg/m2 (95% confidence interval (CI) 27 to 30) and mean age at surgery was 63 years (95% CI 61 to 66). Maximum total point motions (MTPMs), medial, proximal, and anterior translations and transversal, internal, and varus rotations were calculated at three, 12, and 24 months. Patient-reported outcome measure data were also retrieved. Results MTPMs at three, 12, and 24...
Background and purpose - There is some concern regarding the revision rate of the Vanguard CR TKA... more Background and purpose - There is some concern regarding the revision rate of the Vanguard CR TKA in 1 registry, and the literature is ambiguous about the efficacy of patient-specific positioning guides (PSPGs). The objective of this study was to investigate the stability of the cemented Vanguard CR Total Knee using 2 different surgical techniques. Our hypothesis was that there is no difference in migration when implanting the Vanguard CR with either PSPGs or conventional technique. We hereby present a randomized controlled trial of 2-year follow-up with radiostereometric analysis (RSA). Patients and methods - 40 TKAs were performed between 2011 and 2013 with either PSPGs or the conventional technique and 22 of these were investigated with RSA. Results - The PSPG (8 knees) and the conventional (14 knees) groups had a mean maximum total point motion (MTPM) (95% CI) of 0.83 (0.48-1.18) vs. 0.70 (0.43-0.97) mm, 1.03 (0.60-1.43) vs. 0.86 (0.53-1.19), and 1.46 (1.07-1.85) vs. 0.80 (0.52-...
Background and purpose - Although the use of patient-specific positioning guides (PSPGs) in total... more Background and purpose - Although the use of patient-specific positioning guides (PSPGs) in total knee replacement (TKR) in theory is promising, the technique has not yet proven its superior- ity compared with the conventional method. We compared radio- logical alignment and clinical outcome between TKR performed with the use of PSPGs and the conventional operation method. Patients and methods - 3 hospitals participated in a prospec- tive trial. 109 patients were randomized to either the conventional method or to the use of PSPGs. Postoperatively a full-length standing anteroposterior radiograph and a postoperative CT scan were taken. On the CT scan the alignments were measured for both the femoral and tibial components in the frontal, sagit- tal, and axial plane. The Knee injury and Osteoarthritis Outcome Score (KOOS), the Eurocol-5D-3L (Eq5D) descriptive system and visual analogue scale (VAS), a pain score (NRS), and range of motion (ROM) were recorded preoperatively, and at 3 mon...
The effect of patellar eversion on ligament laxity measurements is still unclear. The purpose of ... more The effect of patellar eversion on ligament laxity measurements is still unclear. The purpose of this study was to investigate the influence of patellar eversion on medial and lateral ligament laxity measurements performed intra-operatively in total knee arthroplasty (TKA). A total of 49 knees (27 female) with mean age 70 years (42-83) and mean body mass index of 28.5 were operated consecutively with a cruciate-retaining prosthesis. Medial and lateral ligament laxity in extension and in 90° of flexion was measured with the spatula-method intra-operatively after implantation of the prosthetic components with the patella everted and thereafter with the patella repositioned. The corresponding changes in gap height and inclination were calculated. A statistically significant increase of 0.6 mm (p < 0.001) in ligament laxity (condylar lift-off) laterally in flexion was found with the patella repositioned compared to everted. No differences were found in extension or medially in flexion. Correspondingly, the flexion gap increased by 0.4 mm (p < 0.001) and the flexion gap inclination increased by 0.6° (p = 0.002) when the patella was repositioned. Earlier research has shown that ligament laxity must be at least 1-2 mm to cause inferior function after TKA. In the current study, we found that the effect of patellar eversion on ligament laxity measurements is too small to be considered clinically relevant. PROSPECTIVE STUDY EVALUATING THE EFFECT OF PATIENT CHARACTERISTICS: Level II.
The Active Straight Leg Raise is a functional test used in the assessment of pelvic girdle pain, ... more The Active Straight Leg Raise is a functional test used in the assessment of pelvic girdle pain, and has shown to have good validity, reliability and responsiveness. The Active Straight Leg Raise is considered to examine the patients' ability to transfer load through the pelvis. It has been hypothesized that patients with pelvic girdle pain lack the ability to stabilize the pelvic girdle, probably due to instability or increased movement of the sacroiliac joint. This study examines the movement of the sacroiliac joints during the Active Straight Leg Raise in patients with pelvic girdle pain. Tantalum markers were inserted in the dorsal sacrum and ilium of 12 patients with long-lasting pelvic girdle pain scheduled for sacroiliac joint fusion surgery. Two to three weeks later movement of the sacroiliac joints during the Active Straight Leg Raise was measured with radiostereometric analysis. Small movements were detected. There was larger movement of the sacroiliac joint of the rested leg's sacroiliac joint compared to the lifted leg's side. A mean backward rotation of 0.8° and inward tilt of 0.3° were seen in the rested leg's sacroiliac joint. The movements of the sacroiliac joints during the Active Straight Leg Raise are small. There was a small backward rotation of the innominate bone relative to sacrum on the rested leg's side. Our findings contradict an earlier understanding that a forward rotation of the lifted leg's innominate occur while performing the Active Straight Leg Raise.
Hip international : the journal of clinical and experimental research on hip pathology and therapy, Jan 2, 2016
Cartilage wear is a concern after hemiarthroplasty. The precise pattern of the progression of wea... more Cartilage wear is a concern after hemiarthroplasty. The precise pattern of the progression of wear has not been evaluated. We previously reported the application of radiostereonetric analysis (RSA) for the measurement of cartilage wear in patients. The purpose of this study was to report the amount and the orientation of the steady state wear of cartilage between 1 and 3 years after bipolar hemiarthroplasty. 22 patients with a bipolar hemiarthroplasty for displaced femoral neck fracture were included. 10 patients completed the mean follow up of 37 months. The cartilage wear was evaluated by calculating the migration of the bipolar head in reference to the markers in the acetabulum using RSA. The mean age of the patients at the final follow-up was 80 (range 67-91) years. The 3-D migration was -0.02 mm (SD 0.30) between 1 and 3 years. The migration in each direction was 0.03 mm (SD 0.49) in medial, 0.03 mm (SD 0.14) in proximal and 0.11 mm (SD 0.29) in posterior directions. 2 patients...
Background and purpose - Computer-assisted surgery (CAS) in total knee arthroplasty (TKA) has bee... more Background and purpose - Computer-assisted surgery (CAS) in total knee arthroplasty (TKA) has been used in recent years in the hope of improving the alignment and positioning of the implant, thereby achieving a better functional outcome and durability. However, the role of computer navigation in TKA is still under debate. We used radiostereometric analysis (RSA) in a randomized controlled trial (RCT) to determine whether there are any differences in migration of the tibial component between CAS- and conventionally (CONV-) operated TKA. Patients and methods - 54 patients (CAS, n = 26; CONV, n = 28) with a mean age of 67 (56-78) years and with osteoarthritis or arthritic disease of the knee were recruited from 4 hospitals during the period 2009-2011. To estimate the mechanical stability of the tibial component, the patients were examined with RSA up to 24 months after operation. The following parameters representing tibial component micromotion were measured: 3-D vector of the prosthe...
Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA, Jan 12, 2016
To investigate whether the intended preoperative planning corresponded with the postoperative com... more To investigate whether the intended preoperative planning corresponded with the postoperative component position after medial UKA using patient-specific positioning guides (PSPGs). Twenty-five consecutive UKAs performed with the PSPG technique (Signature™) were included. Two independent observers performed postoperative CT measurements. The preoperative angles for the femoral component were defined in the frontal plane as 0°. In the first eight cases, a femoral component with single peg was inserted, and the flexion of the femoral component was set to 5°. In the last 17 cases, a twin-peg component was used and flexion set to 10°. In the axial plane, the femoral component was on average set at 2.5° internal rotation. The preoperative tibial component angles in the frontal and axial plane were defined as 0° and in the sagittal plane as 4° in flexion. The postoperative femoral component angles were on average 0.8° of valgus (SD 3.2, range 12.2° valgus to 5.1° varus, n.s., CI -2.1 to 0....
Elementary geometrical shape (EGS) models are useful in radiostereometric analysis (RSA) on hip s... more Elementary geometrical shape (EGS) models are useful in radiostereometric analysis (RSA) on hip stems because tantalum markers attached to the stems can be omitted. In order to create an EGS model of a femoral stem, the center of the femoral head has to be identified. The contour of the femoral head is recommended to be used. However, the contour of the femoral head cannot be detected exclusively by computer if it is combined with a bipolar head or a metal cup. We therefore hypothesized that the contour of the outer head of bipolar hemiarthroplasty can be included in the EGS model as well as the femoral head contour. We calculated the time required for the detection of the contour, the precision of analysis and the stem micromotion at 2 years using the two different methods in the same picture set and compared the results. The detection of the bipolar head contour was 10 times faster than that of the femoral head contour. The precision for subsidence was 0.16mm in EGS RSA with the femoral head contour, and 0.15mm with the bipolar head contour (p=0.68). The precisions were comparable and clinically acceptable. There was no significant difference between the results of the 2-year micromotion with the two different methods. We conclude that this new method is applicable to measure stem micromotion of hemi-arthoplasty with EGS RSA and the method facilitates the Radiostereometric analysis.
Journal of Bone Joint Surgery British Volume, Sep 1, 2012
Background Tranexamic acid (TA) in total knee replacement surgery (TKR) has shown marked reductio... more Background Tranexamic acid (TA) in total knee replacement surgery (TKR) has shown marked reduction in bleeding and blood transfusion. There are little data on TA in revision TKR. From February 2008 all patients having primary or revision TKR received TA 10mg/kg × 2. We whished to evaluate the effect and possible complications of TA. Patients and Methods 49 patients had revision TKR from January to August 2010. 21 patients (group I) operated before the regular use of TA were compared to 28 patients (group II) receiving TA. The groups were compared according to bleeding, blood transfusion, postoperative complication and type of revision. Revision TKR was compared to 157 primary TKR (94 operated without TA (group III) and 63 who received TA (group IV). Results Group I: Preoperative Hgl 13.6g/dl (9.2–15.3), reduction in hgl 3.9g/dl (1.0–5.7), bleeding 1040ml (380–2100). 6 patients (28.6%) needed blood transfusion. 7 patients were admitted to cell-saver and were given mean 400 ml blood (150–730). There were 6 revisions from uni-prostheses to TKR and 15 was revision of TKR. There was no difference in bleeding between this to groups (980ml/1030ml). Group II: Preoperative Hgl 14.2g/dl (11.2–18.6), reduction in hgl 3.3g/dl (1.4–8.3), bleeding 490ml (120–1050) (47.1% reduction in bleeding volume (p There was 8 revisions from uni-prostheses to TKR and 21 was revision of TKR. There was no difference in bleeding between this two groups (510ml/570ml). Group III: Preoperative Hgl 14.2g/dl (10.1–17.4), reduction in Hgl 3.5g/dl (1.1–7.7), bleeding 1048ml (50–2230). 15 patients (16%) needed blood transfusion. Group IV: Preoperative Hgl 13.7g/dl (11.6–18.1), reduction in Hgl 2.76g/dl (1.2–4.8) (p=0,014), bleeding 370ml (130–960) (64.5% reduction in volume (p There was no statistically significant difference in bleeding between primary and revision TKR (p=0.18). Conclusion Our results shows that TA reduces bleeding and the need for blood transfusion markedly. The TA groups had no increase in any complications.
Screws, pegs and hydroxyapatite-coating are used to enhance the primary stability of uncemented c... more Screws, pegs and hydroxyapatite-coating are used to enhance the primary stability of uncemented cups. We present a 14-year follow-up of 48 hips randomized to four groups: press-fit only, press-fit plus screws, press-fit plus pegs and hydroxyapatite-coated cups. Radiostereometric migration measurements showed equally good stability regardless cup augmentation. The mean wear rate was high, 0.21mm/year, with no differences between the groups. Seven hips had radiographical osteolysis but only in hips with augmented cups. Cups without screw-holes compared with cups with screw-holes resulted in better clinical outcome at the 14-year follow-up. Thus, augmentation of uncemented cups with screws, pegs, or hydroxyapatite did not appear to improve the long-term stability compared with press-fit only.
Background and purpose - There have been few comparative studies on total knee replacement (TKR) ... more Background and purpose - There have been few comparative studies on total knee replacement (TKR) with cemented tibia and uncemented femur (hybrid TKR). Previous studies have not shown any difference in revision rate between cemented and hybrid fixation, but these studies had few hybrid prostheses. We have evaluated the outcome of hybrid TKR based on data from the Norwegian Arthroplasty Register (NAR). Patients and methods - We compared 4,585 hybrid TKRs to 20,095 cemented TKRs with risk of revision for any cause as the primary endpoint. We included primary TKRs without patella resurfacing that were reported to the NAR during the years 1999-2012. To minimize the possible confounding effect of prosthesis brands, only brands that were used both as hybrids and cemented in more than 200 cases were included. Kaplan-Meier survival analysis and Cox regression analysis were done with adjustment for age, sex, and preoperative diagnosis. To include death as a competing risk, cumulative inciden...
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