[On treatment of injuries of the shoulder-edge joint].
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Biomedical subjects
Publications and source records attributed to D Hohmann.
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The development of translatory displacement in the lower cervical spine is discussed with reference to the kinematics of the cervical motion segment. Anterior dislocation due to degenerative changes is discussed in its relation to the anatomical conditions and in its effect on the spinal cord. Three cases of cervical myelopathy due to degenerative anterolistesis are described. Operative reposition and dorsal fusion was performed.
From June 1988 to January 1991 the efficacy of a low-dose (5 x 2 Gy) versus a high-dose (10 x 2 Gy, resp. 5 x 3,5 Gy) prophylactic postoperative radiotherapy was assessed in a prospective randomized trial. 60 patients at the highest risk for formation of heterotopic ossification (HO) were included in this study, i.e. patients that presented already HO in the ipsi- or contralateral hip at the time of surgery. After both irradiation regimen the incidence and severity of HO was significantly less than without prophylaxis; there was no significant difference (regarding the severity of HO, the hip score (16) and the hip mobility) between the two regimen.
From a sequence of planar CT-pictures of the hip joint the diagnostically relevant contours are extracted on a graphic monitor by means of an image analysis process. To enable this an image-preprocessing has been needed to improve quality of the CT-pictures. From theses contour data, a mathematical surface model of the hip joint will be derived with well-known methods to simulate osteotomy.
The rationale of uncemented taper stems is based on fixation in the proximal portion of the femoral diaphysis, a self-locking principle, and a low modulus of elasticity. The aim of this study was to evaluate a collarless femoral component designed to be a three-dimensional taper for press-fit insertion with regard to clinical outcome, efficacy of fixation, incidence of osteolysis, and periprosthetic bone-remodeling. The first 48 consecutive patients (50 hips) with osteoarthritis who had had primary total hip arthroplasty using the Cerafit Multicone stem and the Cerafit Triradius-M press-fit cup with alumina-alumina pairing (Ceraver Osteal, Paris, France) were followed-up for a mean of 2.3 years (2 to 2.5 years). The mean age of patients at index operations was 52.5 years. Current criteria were used for clinical and radiological assessment. Quantitative evaluation of periprosthetic bone-remodeling was prospectively assessed using computed tomography. Clinical and radiological follow-up was obtained in all hips. Forty-nine hips (98%) were clinically rated good or excellent, one hip (2%) was rated fair, owing to a persisting limp. The mean preoperative Harris Hip Score was rated 62, and it has improved to 93.5 at the time of follow-up. One hip (2%) had marked postoperative thigh pain. This pain had disappeared at 3-month follow-up. All stems showed radiological signs of stable fixation by bone ingrowth. No stem required revision. Thirty-four hips (68%) had either no change in femoral bone density or only patchy loss of bone density isolated to Gruen zones 1 and 7. Sixteen hips (32%) had some reduction of bone density isolated to zone 1. Radiolucencies without progression were found in zones 1 and 7 in 3 hips (6%), and in zone 1 alone in 3 other hips (6%). A slight cortical hypertrophy was seen in 3 hips (6%). Twenty-three hips (46%) developed radiographic appearance of bone apposition at the stem tip as partial pedestal (19 hips) and as complete pedestal (4 hips). No signs of cup loosening were detected at follow-up. Twenty-four patients (25 hips) were eligible for computed tomography. The mean decrease of the overall bone mineral density in the metaphyseal portion of the femur one year after insertion of the stem was rated 15.4%, and the mean decrease of the cortical bone mineral density was rated 17.2%. On the other hand, a mean decrease of the cortical bone mineral density of less than 5% was observed in the diaphyseal portion of the femur around the implant. The clinical and radiological results of the Cerafit Multicone stem at a mean follow-up of 2.3 years are very promising and do not contrast with those achieved using other uncemented stems with tapered design. Furthermore, results of quantitative evaluation of periprosthetic bone-remodeling were considered satisfactory favourably with others reported in the literature using stems inserted without cemented.
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It was the purpose of the study to investigate the initial stability, with or without screws, of 3 acetabular components with press-fit anchoring, by measuring bone-prosthesis micromovements during the application of physiological loading on the hip simulated in the laboratory. The prostheses, already used clinically, were characterized by different shapes and coatings. For the purposes of the study a total of 30 acetabula were used in 10 human pelves in polyurethane and 5 human pelves preserved at -20 degrees. The pelves were assembled on a hydraulic bench test with a steel jig that could be oriented, and they were cemented with polymethylmethacrylate. Three electromagnetic transducers with sensitivity of up to 1 micron (+ 500 microns) were used to measure the micromovements between the prosthesis and the acetabular rim in its three anatomical quadrants. Bone-prosthesis micromovements were recorded during 5 consecutive load tests, from 0 to 2.39 kN (244 kg). Experimental studies have shown that bone-prosthesis micromovement that exceeds 150 microns obstructs bone integration. The most significant micromovement was observed for all of the prostheses, without accessory screws, in the iliac quadrant, but only the hemispherical one with a semi-smooth surface in zirconium oxide surpassed the threshold of 150 microns. Prostheses with a porous surface demonstrated good stability (102 +/- 33 microns and 94 +/- 36 microns, respectively). None of the prostheses demonstrated micromovement exceeding 90 microns in the area corresponding to the pubis and the ischium. The use of 2 accessory screws sensitively increased the stability of all of the prostheses on the ilium, reducing the average micromovement by 40 microns. Reduction of micromovement was less on the pubis and on the ischium.