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Biomedical subjects

U Dorn

Publications and source records attributed to U Dorn.

26 records · Page 2Linked to original sources
PubMedDate not supplied

[Prophylaxis of heterotopic ossification in hip revisions with 7 Gy single-dose radiation].

AIM OF STUDY: Radiation therapy is an established method for the prevention of heterotopic ossification. The aim of this study was to assess whether radiation therapy is also effective in revision arthroplasties. METHOD: 143 hips were irradiated with 7 Gy anterior-posterior applied single dose radiation, on one of the first four days after revision surgery. RESULTS: After an average follow-up of 18 months, 107 hips were evaluated radiographically using Brooker's criteria. In comparison to the immediate postoperative findings (26 % showed no heterotopic ossification, 66 % had Brooker I, 5 % Brooker II, and 3 % Brooker III), at final follow-up 19 % showed no heterotopic ossification, 66 % had Brooker I, and 7.5 % Brooker II and III. New ossification or an increase of one grade was found in 12 %, of two grades in 4 %. Grade 0 showed significantly more ossifications. Gender (p = 0.43), age (p = 0.43), the type of revision surgery (p = 0.36), the day of radiation (1st day vs. 2nd, 3rd, 4th day; p = 0.46) had no significant influence on this increase. There was no correlation between pain score and Brooker grades (p = 0.755). There was a significantly (p < 0.01) negative correlation (r = - 0.31) between the Brooker grades and flexion. CONCLUSION: Radiation therapy with 7 Gy single dose effectively prevents the new formation of heterotopic ossification or the progression of ossifications after revision surgery. To prevent a decrease in the range of motion due to HO after revision surgery, HO should be removed intraoperatively.

Adult↗
PubMedDate not supplied

[Polyethylene liner dislocation in Harris Galante acetabular components].

AIM: Dislocation and subsequent dissociation of the polyethylene liner as a result of failure of the acetabular locking mechanism is a potential source of failure in the Harris-Galante acetabular component. The purposes of this study are to present seven cases with a liner dislocation due to failure of the liner locking mechanism. METHOD: Between March 1997 and December 2001, seven patients who had had a total hip arthroplasty presented with clinical and radiologic signs of liner dislocation and signs of polyethylene wear of the liner from a Harris Galante acetabular shell. In all cases the intraoperative findings showed evidence of failure of the liner locking mechanism and subsequent dislocation. The medical records, radiographs, operative notes and explanted retrieved components were reviewed. RESULTS: The components had been in situ for an average of 5.3 years (range 1-9 years). Two components were first generation, five were second generation. The symptoms developed spontaneously in five patients, the other two patients described a minor trauma. Radiographs showed eccentric position of the head in all cases. All acetabular components showed an excellent stability intraoperatively, nevertheless we had to remove the well fixed acetabular shell due to complete destruction of the liner locking mechanism in two cases. Treatment consisted of revision of the shell in two patients and exchange of the liner in five patients. All retrieved liners showed severe deformation and/or fracture of the rim. CONCLUSION: Harris Galante modular acetabular components have been used widely for primary and revision arthroplasty. The survival of this implant has been well documented in the literature. Failure of the liner locking mechanism and following dislocation or fracture of the polyethylene liner is a potential cause of failure which may possibly occur more often than the literature to date has documented. We report seven cases of liner dislocation, in which two acetabular components had to be removed completely due to destruction of the liner locking mechanism. In the other five cases exchange of the liner was possible thanks to well timed revision. We believe that, as the liner wears and becomes loose due to an inefficient locking mechanism, the load increases on the polyethylene rim until it deforms or fractures. As a consequence of the prosthetic design at that stage nothing can prevent the liner from rotating out of the shell.

Acetabulum↗
PubMedDate not supplied

[Anterior intertrochanteric ossification after total hip arthroplasty].

AIM: Heterotopic paraarticular ossifications are usually identified by an anterior-posterior radiograph of the corresponding hip and are consecutively classified by the well accepted methods of Brooker, Arcq or deLee. In these methods ossifications are solely evaluated by the means of a single a-p radiograph, hence a major part of ossifications located in the anterior intertrochanteric region cannot be evaluated. Our study deals with the incidence of ossifications exclusively verifiable by an axial radiograph. METHOD: In the present study 209 patients' axial radiographs were retrospectively analysed by using our simple method of classification. In the axial projection these ossifications are situated anterior of the intertrochanteric region, therefore we created the term "anterior intertrochanteric ossification (AIO)". After developing a simple topographic scheme we classified these appearances by localisation and size. RESULTS: After total hip arthroplasty by using the transgluteal approach ossifications situated in the anterior intertrochanteric region can develop. These ossifications appear as bone islands, shield or clip like (without fixed connection to the femoral cortical bone) or as solid exostoses. Due to their strict anterior localisation these formations are often solely verifiable by the means of an axial (Lauenstein) radiograph. We were able to identify anterior intertrochanteric ossifications (AIO) in 97 out of 209 patients (48.4 %), 27 patients (13 %) developing an anterior intertrochanteric ossification were classified grade 0 according to the methods of Brooker, Arcq and deLee. CONCLUSION: According to the widely accepted methods of classification of paraarticular ossifications depending on a single a-p radiograph of the corresponding hip, 13 % of paraarticular ossifications would remain undocumented because of their strict anterior intertrochanteric position.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMedDate not supplied

[Roentgen criteria and radiologic results of the Hofer-Imhof (H-I) threaded acetabulum cup in first time implantation].

The Hofer-Imhof cup consists of a parabola-shaped titanium acetabular component with flat threads. These flat threads are designed to be self-cutting and allow accurate insertion without incarceration, even in sclerotic bone. In a prospective study conducted from May 1988 to July 1989, 143 Hofer-Imhof cups were implanted. Radiographic assessment included initial bone contact, cup position, fixation on osteophytes, presence of any radiolucencies or sclerosis, cup migration and bone ingrowth. Initial prosthesis fit was evaluated with a 20 degrees caudally angled anteroposterior X-ray for accurate demonstration of the threads. 119 of the Hofer-Imhof cups (83.2%) were available for radiographic follow-up at a mean of 65 months (min. 37 mo., max. 95 mo.). One cup required revision after 23 months due to infection. The cups had an average inclination of 47 degrees, and complete bone contact was evident in 86.6% on the postoperative X-ray. In 8.4% of the cups, some threads were not in contact with bone at the edge of the acetabulum. At final follow-up, 82.4% had complete bone ingrowth without any evidence of radiolucency (type I), 15.1% had near-complete bone ingrowth with minimal radiolucencies (type II), and 2.5% had predominantly fibrous fixation (type III). One cup (0.8%) showed excessive migration. The technique of anchorage using a flat thread, minimal bone resection as a result of the parabolic shape and the sandblasted titanium surface are the characteristic features of the Hofer-Imhof threaded cup and produce good medium-term results in primary hip arthroplasty.

Acetabulum↗
PubMedDate not supplied

[Spondylodiscitis as a dominant early symptom of juvenile ankylosing spondylitis].

A 12-year-old female (HLA-B27 negative) presented with unilateral low back pain and sterno-clavicular arthritis. Six months after onset the clinical and radiological findings determined spondylodiscitis L1/2. On the basis of the clinical findings (oligoarthritis, symptomatic sacroilitis, spondylodiscitis), juvenile ankylosing spondylitis was suspected. The diagnosis was corroborated 18 months after the first occurrence of symptoms by the appearance of typical changes in the sacroiliac joint that are indicative of juvenile ankylosing spondylitis. Because of persisting antibodies against Borrelia burgdorferi, the possibility of B. burgdorferi-induced reactive arthritis with involvement of the axial division of the skeletal system was considered. After 3.5 years of observation the condition showed a benign course with radiologically observable consolidation of the spondylodiscitis. To our knowledge, this is the second case described of juvenile ankylosing spondylitis with spondylodiscitis as a dominating feature.

Arthrography↗