| 1. |
- Skripitz, Ralf, et al.
(författare)
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Early effect of parathyroid hormone (1-34) on implant fixation
- 2001
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Ingår i: Clinical Orthopaedics and Related Research. - 0009-921X .- 1528-1132. ; :392, s. 427-432
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Tidskriftsartikel (refereegranskat)abstract
- Intermittent systemic administration of parathyroid hormone increases bone formation by stimulating osteoblastic activity. The current study determined how parathyroid hormone (1-34) administration influences the bony fixation of stainless steel screws with time. A screw was implanted in the left tibia and a metal rod was implanted in the right tibia in 30 adult male rats that then were injected three times a week with human parathyroid hormone (1-34) at 60 ╡g/kg/injection (n = 15) or saline (n = 15). The animals were euthanized after 1, 2, or 4 weeks of treatment. Eight additional rats received only the screw and were euthanized immediately after implantation. No significant effects of parathyroid hormone on body weight change or ash weight of the femurs were seen. The degree of fixation was assessed by measuring pullout strength of the screws. The mean pullout strength immediately after implantation was 12 N. The pullout strength of the group injected with saline was 33 N after 1 week, 23 N after 2 weeks, and 41 N after 4 weeks. The pullout strength of the group injected with parathyroid hormone increased to 43 N after 1 week, 58 N after 2 weeks, and 100 N after 4 weeks. The increase at 2 and 4 weeks was statistically significant. Strength reflects the mechanical properties of the bone within the screw threads. The contralateral tibia with its metal rod was used for blinded histologic assessment. Parathyroid hormone increased the fraction of the metal surface having contract with bone without an intervening soft tissue layer from 45% to 69% after 1 week. The current results suggest that intermittent parathyroid hormone treatment can enhance early implant fixation by enhancing the density of the surrounding bone and by increasing the implant bone contact.
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| 2. |
- van der Donk, S, et al.
(författare)
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Rinsing morselized allografts improves bone and tissue ingrowth
- 2003
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Ingår i: Clinical Orthopaedics and Related Research. - 0009-921X .- 1528-1132. ; :408, s. 302-310
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Tidskriftsartikel (refereegranskat)abstract
- Bone defects in revision hip surgery can be reconstructed with impacted morselized bone grafts. Rinsing these trabecular allografts may enhance graft incorporation by washing out immunogenic factors present in blood, marrow, and fat. However, it has been proposed that impaction of the graft releases biologically active factors, which can provide sufficient activity to stimulate new bone formation. Rinsing before impaction could enhance bone allograft incorporation, but rinsing after impaction could diminish the incorporation process of impacted bone graft. To study the effect of rinsing and impaction of morselized bone grafts on bone ingrowth, a bone chamber study was done in goats. Autografts and allografts were divided into three treatment groups: (A) impacted, (B) rinsed and impacted, and (C) rinsed, impacted, rinsed, and impacted again. Ten goats received three bone chambers in each proximal tibia. The chambers were filled with either allograft or autograft, yielding six different implants per goat. After 6 weeks, histologic analyses were done and bone and tissue ingrowth were measured. New bone and total tissue ingrowth were higher in autografts than in allografts, especially in the non-rinsed group. With rinsing, total tissue ingrowth increased in the allograft group to approach that of autografts. Rinsing after impaction did not additionally alter bone ingrowth. The current findings show that incorporation of allografts can be improved by rinsing the grafts before impaction.
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| 3. |
- Östman, Bengt, et al.
(författare)
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Tourniquet-induced ischemia and reperfusion in human skeletal muscle
- 2004
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Ingår i: Clinical Orthopaedics and Related Research. - 0009-921X .- 1528-1132. ; 418, s. 260-265
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Tidskriftsartikel (refereegranskat)abstract
- Microdialysis conceivably enables longitudinal and simultaneous investigation of several metabolites by repeated measurements in skeletal muscle. We used and evaluated microdialysis as an in vivo method to characterize the time-course and relative kinetics of pyruvate, glucose, lactate, glycerol, hypoxanthine, uric acid, and urea, in skeletal muscles, exposed to ischemia and reperfusion, in eight patients having arthroscopic-assisted anterior cruciate ligament reconstruction. A dialysis probe was implanted before surgery in the rectus femoris muscle. Dialysate samples were collected at 10-minute intervals at a flow rate of 1 microL/minute until 2 hours after tourniquet deflation. Ninety minutes of ischemia resulted in accumulation of lactate (234% +/- 38%), hypoxanthine (582% +/- 166%), and glycerol (146% +/- 46%), consumption of glucose (54% +/- 9%) and pyruvate (16% +/- 44%), and a slight decrease of urea (78% +/- 11%) compared with baseline (100%). Uric acid was unchanged (95% +/- 12%). Within 90 minutes after tourniquet deflation the concentrations were virtually normalized for all measured metabolites, suggesting that the duration of ischemia was well tolerated by the patients. The results indicate that the use of microdialysis for monitoring energy metabolic events during orthopaedic surgery that requires ischemia and reperfusion is feasible and safe.
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| 4. |
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| 5. |
- Ahrengart, L, et al.
(författare)
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A randomized study of the compression hip screw and gamma nail in 426 fractures
- 2002
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Ingår i: Clinical Orthopaedics and Related Research. - 0009-921X. ; :401, s. 209-222
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Tidskriftsartikel (refereegranskat)abstract
- A prospective, randomized study comparing the compression hip screw with the Gamma nail in the treatment of 426 intertrochanteric fractures is reported. The median patient age was 80 years, and 71 % were women The compression hip screw operation took less time except in Evans Type 5 fractures. Blood loss generally was less in the compression hip screw group except in patients with Type 5 fractures. The most frequent surgical problem for patients in the Gamma group was problems with distal locking. Cephalic position of the femoral head screw and cut-out were seen more often in the Gamma nail group. The Gamma nail more frequently preserved the fracture position obtained perioperatively. Whether there was distal locking of the Gamma nail in unstable fractures did not seem to affect the healing rate. Additional fissures or fractures in the proximal femur occurred during five Gamma nail operations and two compression hip screw operations. Postoperative walking ability did not differ between the groups. At 6 months 88% of the fractures were healed. In less comminuted fractures, the compression hip screw method is the preferred method of treatment whereas the Gamma nail is an alternative treatment for more comminuted Evans Type 5 fractures.
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| 6. |
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| 7. |
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| 8. |
- Björkman, Anders, et al.
(författare)
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Factor V leiden and prothrombin gene mutation: risk factors for osteonecrosis of the femoral head in adults.
- 2004
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Ingår i: Clinical Orthopaedics and Related Research. - 0009-921X. ; :425, s. 168-172
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the current study was to determine whether factor V Leiden and the prothrombin 20210A gene mutation are risk factors for osteonecrosis of the femoral head in different etiologic groups of osteonecrosis in adults and whether patients with idiopathic osteonecrosis of the femoral head have a higher frequency of thromboembolic events compared with the general population. We investigated 63 adult patients with nontraumatic osteonecrosis of the femoral head for etiologic factors, such as corticosteroid medication and alcohol abuse, and the occurrence of factor V Leiden and the prothrombin 20210A gene mutation. In 35 patients, the disease was considered idiopathic and 10 of these patients (29%) had factor V Leiden or the prothrombin 20210A gene mutation or both. Mutations in factor V or the prothrombin 20210A gene were significantly more frequent in patients with idiopathic osteonecrosis than in a population of healthy control subjects (odds ratio, 2.7; 95% confidence interval range, 1.2-5.8) and in patients with osteonecrosis caused by corticosteroid medication or alcohol abuse (odds ratio, 10.8; 95% confidence interval range, 1.4-84). 36% of patients with a gene mutation had had a thromboembolic event compared with 8% of patients without a gene mutation. Thromboembolic events were more common among patients with idiopathic osteonecrosis (17%) compared with the general population (4%) and with patients with osteonecrosis caused by corticosteroid medication or alcohol abuse (7%).
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| 9. |
- Brittberg, Mats, 1953, et al.
(författare)
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Autologous chondrocytes used for articular cartilage repair: an update.
- 2001
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Ingår i: Clinical orthopaedics and related research. - 0009-921X. ; :391 Suppl
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Forskningsöversikt (refereegranskat)abstract
- Articular cartilage in adults has a poor ability to self-repair after a substantial injury; however, it is not known whether there is a cartilage resurfacing technique superior to the existing techniques. It is not satisfactory that at the beginning of the new millennium, there still is a lack of randomized studies comparing different cartilage repair techniques and there still is little knowledge of the natural course of a cartilaginous lesion. To date, various articular cartilage resurfacing techniques have the potential to improve the repair of cartilage defects and reduce the patient's disability. One such cartilage repair technique is autologous chondrocyte transplantation combined with a periosteal graft. Since the first patient was operated on in 1987, much interest in cartilage repair and cell engineering has emerged. The experience with autologous chondrocyte transplantation during the past 13 years with in vitro chondrocyte expansion, cartilage harvest, and postoperative biopsy technique is discussed, and the latest followup of 213 consecutive patients in different subgroups with 2 to 10 years followup is presented. The technique gives stable long-term results with a high percentage of good to excellent results (84%-90%) in patients with different types of single femoral condyle lesions, whereas patients with other types of lesions have a lower degree of success (mean, 74%).
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| 10. |
- Digas, Georgios, 1963, et al.
(författare)
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The Otto Aufranc Award. Highly cross-linked polyethylene in total hip arthroplasty: randomized evaluation of penetration rate in cemented and uncemented sockets using radiostereometric analysis
- 2004
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Ingår i: Clin Orthop Relat Res. - 0009-921X. ; :429, s. 6-16
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Tidskriftsartikel (refereegranskat)abstract
- The annual wear rate in polyethylene articulations should be 0.1 mm or less to avoid future osteolysis. Highly cross-linked polyethylene shows an 80 to 90% wear reduction in hip simulator testing, but the clinical documentation of this new polyethylene is still inadequate. We evaluated the highly cross-linked polyethylene in two prospective randomized clinical studies. Thirty-two patients (12 men, 20 women; 64 hips) with a median age of 48 years (range, 29-70 years) with bilateral primary or secondary arthrosis of the hip had hybrid total hip arthroplasty with liners made of highly cross-linked polyethylene on one side and conventional polyethylene on the other. Twenty-seven patients in this study have passed 2 years followup. A further group, comprised of 60 patients (61 hips) with a median age of 55 years (range, 35-70 years), was randomized to receive either highly cross-linked polyethylene or conventional cemented all-polyethylene of the same design. Forty-nine of these 60 patients have been observed for 3 years. In both studies all patients received Spectron stems with 28-mm Co-Cr heads. Radiostereometric examinations with the patient supine or standing were done at regular intervals. Wear was measured in the supine position from the first postoperative week, whereas standing examinations were initiated 3 months after the operation. The penetration rate almost was identical in the study and control groups at 6 months after the operation. Thereafter, the penetration rate leveled out in the two groups with highly cross-linked polyethylene. At 2 years the highly cross-linked polyethylene liner showed 62% lower proximal penetration and 31% lower total (three-dimensional) penetration when the patients were examined in supine position. The highly crosslinked all-polyethylene cemented cups showed lower proximal penetration in both positions. The better wear performance of highly cross-linked polyethylene could increase the implant longevity. Longer followup is needed to evaluate if this new material is associated with less occurrence of osteolysis.
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