Biomedical subjects

Arild Aamodt

Publications and source records attributed to Arild Aamodt.

6 recordsLinked to original sources

PubMed2006

Improved comfort and function of arm prosthesis after implantation of a Humerus-T-Prosthesis in trans-humeral amputees.

The use of arm prosthesis in trans-humeral amputees is limited; due to the cone form of the amputation stump. A Humerus-T-Prosthesis was implanted in three patients to create artificial humerus condyles. Two of the patients were successfully rehabilitated with the application of a new type trans-humeral arm prosthesis. This arm prosthesis had a socket which is suspended and stabilized by the humerus and implant only. Traction and rotational stability were secured by adjustable pressure adaptation around the artificial condyles. The third patient developed a pressure wound over the lateral part of the artificial condyle that later healed. He also was subject to a new trauma with a fracture of the ipsilateral scapula and until now has had limited the use of his new arm prosthesis. It was concluded that this new concept for prosthesis fitting of trans-humeral amputees looks promising, but alternative designs of the implant should be tested.

Adult↗

PubMed2005

Differences in stability and bone remodeling between a customized uncemented hydroxyapatite coated and a standard cemented femoral stem A randomized study with use of radiostereometry and bone densitometry.

The custom made Unique stem is designed to fit closely to the metaphyseal region of the femur in order to obtain maximum mechanical stability and optimal load transfer. Thirty-seven patients (38 hips) with non-inflammatory arthritis were randomized to the uncemented custom made Unique stem or the Elite Plus stem inserted with cement. The patients have been followed clinically as well as with radiostereometry (RSA) and Dual-energy X-ray Absorptiometry (DXA) for 2 years. After 2 years the RSA result showed minimal translation and rotation for the Unique stem while the Elite Plus rotated slightly (mean 1.05 degrees) into retroversion. Compared to previous studies the Elite Plus was as stable as the Charnley prosthesis. The DXA results showed a significantly higher proximal and total (10% for the Unique versus 5% for Elite) bone loss for the Unique stem compared to the Elite Plus. Thus the optimal proximal press-fit of the custom made stem did secure a stable fixation, but did not decrease the proximal bone loss.

Absorptiometry, Photon↗

PubMed2005

A quantitative and qualitative analysis of bone remodelling around custom uncemented femoral stems: a five-year DEXA follow-up.

BACKGROUND: After total hip replacement bone remodelling is determinant for the implant survival. This study asked whether the immediate postoperative amount and distribution of bone can predict the changes in bone amount and distribution after five years in the case of younger patients with custom uncemented implant. METHODS: We investigated 17 hips with a mean follow-up of 5.1 years. The average patient age at follow-up was 48.5 years. We used immediate postoperative and five-year dual energy X-ray absorptiometry measurements of bone mineral content, density, and projected bone area in seven local zones forming a partition of the upper femur. A correlation was sought between the preoperative variables and the five-year variation. Qualitative bone remodelling was analysed considering each local zone in a density-area plane. Based on geometrical considerations, we introduced an index of structural remodelling, which expresses the preponderance of internal remodelling against external modelling. FINDINGS: The bone mineral content at operation correlated significantly with its relative decrease locally laterally mid-proximally and medially (P<0.01), distally, and globally for the femur (P<0.05). For the bone mineral density, the correlation was significant distally, medially and globally (P<0.05). The bone projected area shows only significant correlation laterally mid-proximally (P<0.01). The index of structural remodelling was significantly positive (P<0.01) in all local zones and was independent of the initial bone amount and structure (P>0.1). INTERPRETATION: High bone mineral content at operation correlates significantly with periprosthetic bone loss after five years in younger patients with cementless custom femoral implant. Independently of the net bone mineral content balance, external modelling is stronger than internal remodelling in all local zones.

Absorptiometry, Photon↗

PubMed2004

External fixation versus locked intramedullary nailing in tibial shaft fractures: a prospective, randomised study of 78 patients.

INTRODUCTION: We performed a prospective, randomised study to compare the Ex-fi-re external fixator (EF) with locked intramedullary (IM) nailing in tibial fractures. Only fractures without soft-tissue problems of importance were included. MATERIALS AND METHODS: Ex-fi-re is a unilateral, dynamic axial fixator with fracture reduction capabilities. The Grosse-Kempf nail was used for nailing. A total of 78 patients with 79 fractures were entered in the study (41 Ex-fi-re, 38 IM nails). RESULTS: Time to radiographic union and full weight-bearing did not differ significantly, but unprotected weight-bearing was achieved earlier in the IM group (12 vs 20 weeks; p<0.001). There were more reoperations due to secondary dislocation in the EF group. There were no differences in final angulation or shortening. After 6 months and 1 year there were no differences in knee motion, ankle motion, fracture site pain or ankle pain. Some 64% of the nailed patients complained of anterior knee pain after 1 year. CONCLUSION: The results were comparable in most respects. Unprotected weight-bearing was achieved earlier after IM nailing. Anterior knee pain was frequent after nailing.

Adolescent↗

PubMed2004

High local concentrations without systemic adverse effects after impaction of netilmicin-impregnated bone.

BACKGROUND: When cancellous bone is impregnated with antibiotics the subsequent release of antibiotics from the bone shows a high early release. Hence, impaction of large amounts of netilmicin-impregnated bone may cause toxic netilmicin values in serum. PATIENTS AND METHODS: We studied kidney and otovestibular function after impacting 50 g of netilmicin-impregnated cancellous bone during revision hip or knee arthroplasty in 20 patients. The bone was impacted in the acetabulum (n = 8), proximal femur (n = 9) and distal femur/proximal tibia (n = 3). Serum creatinine concentration was measured and audiometry was performed before and after the operation. Netilmicin concentrations in serum, joint fluid, and in urine were recorded postoperatively at regular intervals. We analyzed pharmacokinetics in two study groups receiving bone impregnated with netilmicin (50 mL), at either 50 mg netilmicin/mL (group I) or 100 mg netilmicin/mL (group II). RESULTS: Neither netilmicin-induced renal toxicity, nor otovestibular toxicity was registered. Peak serum netilmicin values in group I and group II were 0.9 (0.5-1.3) mg/L and 1.8 (0.6-4.0) mg/L, respectively (p = 0.04). Peak netilmicin concentrations in wound drainage fluid in group I and group II were 237 (9-647) mg/L and 561 (196-1132) mg/L, respectively (p = 0.01). In both groups, netilmicin was recovered in urine samples for approximately 4 weeks. INTERPRETATION: 50 grams of cancellous bone impregnated with 100 mg/mL netilmicin solution was impacted in the hip or knee joint with no adverse effects. Extremely high local concentrations of netilmicin in joint fluid were recorded postoperatively. The use of antibioitic-impregnated cancellous could be an option when performing revision of hip and knee prostheses.

Adult↗

PubMed2004

Documentation of hip prostheses used in Norway: a critical review of the literature from 1996--2000.

We have conducted a systematic review of the scientific literature concerning outcome and clinical effectiveness of prostheses used for primary total hip replacement (THR) in Norway. The study is based on two Health Technology Assessment reports from the UK (Faulkner et al. 1998, Fitzpatrick et al. 1998), reviewing the literature from 1980 to 1995. Using a similar search strategy, we have evaluated the literature from 1996 through 2000. We included 129 scientific and medical publications which were assessed according to a specific appraisal protocol. The majority (72%) were observational studies, whereas only 9% were randomized studies. We could not retrieve any peer-reviewed documentation for one third of the implants. The Charnley prosthesis had by far the best and most comprehensive evidence base with better than 90% implant survival after about 10 years. Survival of the Charnley prosthesis declines by about 10% during each of the two following decades. Except for the Charnley and Lubinus IP, no other prosthesis on the market in Norway has given long-term results (> 15 years). 5 other cemented implants have given comparable results at about 10 years of follow-up. Some uncemented stems have shown promising medium-term outcome, but no combination of uncemented cup and stem fulfilled the benchmark criterion of > or = 90% implant survival at 10 years, which we propose as a minimum requirement for unrestricted clinical use for prostheses used in primary THR. New or undocumented implants should be introduced through a four-step model including preclinical testing, small series evaluated by radiosterometry, randomized clinical trial involving comparison with a well-documented prosthesis, and finally, surveillance of clinical use through registers.

Arthroplasty, Replacement, Hip↗