| 1. |
- Axelsson, Paul, et al.
(författare)
-
Radiostereometry in lumbar spine research.
- 2006
-
Ingår i: Acta Orthopaedica. Supplementum. - : Medical Journals Sweden AB. - 1745-3690 .- 1745-3674 .- 1745-3682. ; 77:323, s. 3-42
-
Forskningsöversikt (refereegranskat)
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Digas, Georgios, 1963
(författare)
-
New polymer materials in total hip arthroplasty. Evaluation with radiostereometry, bone densitometry, radiography and clinical parameters
- 2005
-
Ingår i: Acta Orthop Suppl. - 1745-3690. ; 76:315, s. 3-82
-
Tidskriftsartikel (refereegranskat)abstract
- AIMS: To evaluate the outcome of different types of polyethylene, bone cements and one design of uncemented fixation with porous and ceramic coating using radiostereometry, bone densitometry, conventional radiography and clinical parameters. MATERIALS AND METHODS: Study I: 201 patients were extracted from 5 prospective randomised studies to evaluate femoral head penetration at two years with radiostereometry in four basic designs, cemented Lubinus and Reflection cups, uncemented Trilogy and Reflection cups. Studies II and III: 60 patients (61 hips) were randomised to receive either highly cross-linked or conventional all PE cups. 32 patients with bilateral arthrosis received hybrid THA with highly cross-linked PE on one side and conventional on the contra lateral side. Femoral head penetration and the migration of the cups were evaluated with radiostereometry in the supine and standing positions. DEXA and conventional radiography were used to evaluate the bone mineral density and radiolucencies around the cemented acetabular component. Studies IV and V: 90 patients (97 and 96 hips respectively) were stratified depended on age, gender, diagnosis and preoperative BMD to create 3 main groups of socket fixation. In the first group fluoride containing cement was used, in the second group Palacos cum Gentamicin and in the third hybrid THA with porous coated HA/TCP cup. In the hybrid group the fixation of the femoral component was again randomised to either of the two cements. The results on femoral and acetabular sides are presented separately in studies IV and V, respectively. RESULTS: Study I: Cups with polyethylene sterilized in EtO had almost twice the proximal and 3D penetration rates compared with gamma-sterilized polyethylene. Regression analysis showed that the type of sterilization, age and weight was the most important factors affecting the penetration rate. Studies II and III: In the cemented study the proximal penetration was lower in the study group independent of position at 3 years, while in the hybrid study the penetration was lower in the study group only in the supine position at 2 years. The migration of the cup did not differ between the plastics in both studies. At 2 years the periprosthetic radiolucency and BMD did not differ significantly between the 2 types of PE used in the cemented study. Study IV: The subsidence of the stem did not differ between the groups, but the periprosthetic BMD decreased more in fluoride cement group at 2 years. Conventional radiography revealed higher progression of radiolucent lines in the Palacos group, but only in one region. Study V: The proximal migration of the cup was almost similar in all three groups. The three dimensional migration was increased in patients with osteoporosis. Postoperative radiolucent lines tended to disappear with use of porous coating covered with HA/TCP. CONCLUSIONS: Study I: EtO sterilized polyethylene increased the femoral head penetration. Age and weight were also important predictors of the penetration rate. Studies II and III: The highly cross-linked polyethylene decreased the penetration rate mainly after one year probably reflecting less wear. The different mechanical properties of the two types of PE studied did not affect the early fixation of the cemented cup. Study IV: There were no obvious advantage of addition of fluoride to acrylic bone cement when used to fixate the femoral component. Study V: Use of fluoride containing cement or uncemented fixation did not improve the early stability of the socket compared to Palacos with Gentamicin.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Weidow, Jonas, 1960
(författare)
-
Lateral osteoarthritis of the knee. Etiology based on morphological, anatomical, kinematic and kinetic observations
- 2006
-
Ingår i: Acta Orthop Suppl. - 1745-3690. ; 77:322, s. 3-44
-
Tidskriftsartikel (refereegranskat)abstract
- This thesis aimed to study osteoarthritis (OA) of the knee and its subgroup with lateral wear (valgus knees). Anatomy, kinematics and kinetics (movements and moments) of the hip and knee joint and the sensitivity and specificity of diagnostic procedures were evaluated. Our hypothesis was that there are biomechanical reasons for development of either lateral or medial OA. The wear pattern of the tibial plateau and the femoral condyles was delineated in 42 patients. The diagnostic accuracy of standing knee radiographs was validated in 34 and reproducibility and validity of the Ahlback classification was studied in 48 patients. The Influence of working conditions or gender on the prevalence of uni or bilateral knee OA was evaluated in 990 patients from 2 hospitals (Varberg and Halmstad) operated during 1985-1994 with knee arthroplasty or proximal tibial osteotomy. For each patient, 3 age- and gender-matched controls were found. Studies of the anatomy of the hip and pelvic regions and the motions and moments in the hip and knee in medial and lateral OA were performed. The detailed kinematics of the knee during active extension in lateral OA were recorded using dynamic radiostereometry (RSA). In both medial and lateral OA the central part of the tibial plateau showed the most pronounced wear (p<0.001), followed by the anterior part in medial OA (p=0.02) and the posterior part in lateral OA (p=0.001). In medial OA the observed difference between the 2 radiographic methods was small and acceptable (median; p=0.05; 0-0.5 mm). In lateral OA there was no consistent underestimation, but larger scatter (median; p=0.04; -0.1-1.2 mm) suggesting less precise determination. The repeatability of the Ahlback classification for one observer was fair (kappa: medial OA: 0.15-0.65; lateral OA: 0.59-0.76), but between observers it was poor (kappa: 0.1). The validity revealed an acceptable sensitivity in both medial (67-95%) and lateral (43--86%) OA but the specificity was low (medial: 11-67%; lateral: 25-75%). Farmers (RR: 1.7; p<0.0005) and building workers (RR: 1.4; p=0.047) run increased risk to undergo surgical treatment because of OA of the knee. Unilateral disease was 3.7 times more common among men. Patients with lateral knee OA had a 14 mm wider pelvis (p=0.001) and those with medial knee OA an 11 mm higher offset (p=0.005). In the gait analysis they showed more outward rotation of the hip (p=0.001) and more inward rotation of the tibia than did patients with medial OA (p=0.001). In lateral OA, the medial femoral condyle translated 7-8 mm forward with 450 flexion whereas controls translated 4 mm less (p=0.03), without any difference of the lateral femoral condyle. Conventional radiographs do not give sufficient information for correct grading, especially in lateral OA where the scatter is high. The joint space can often be seen on radiographs despite presence of bone attrition as observed on the preparations. Increased incidence of unilateral disease in men and building workers suggests that this joint disease more commonly originates from previous trauma. Our findings suggest that the occurrence of medial or lateral OA has a biomechanical background originating from pelvis and hip anatomy.
|
|
| 8. |
|
|
