Biomedical subjects
Publications and source records attributed to E Morscher.
The various currently used methods of stabilisation of the cervical spine are described. The choice of the procedure depends mainly on the classification of the lesion and on the biomechanics of the injured segment. Better knowledge of the biomechanics have led to the development of more reliable and safer implants.
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We introduce a simple method of sonographic determination of femoral neck anteversion in children with which the even difficult angels in terms of measurement, those up to 70 degrees, can be measured with sufficient reliability: The examination was done with a defined internal 40 degree rotation of the legs reached by a supporting wedge. We proved this method on 55 children's hips of which we already had an existing radiologic determination of the anteversion angle. Compared to the radiological results we found an average deviation of 3.6 degrees (standard deviation = 3.2).
A review on the experience and the results with 184 PCA (Porous Coated Anatomic)-knee endoprostheses is given, performed at the Department of Orthopaedic Surgery, Basel, from 1981 to 1984 with an observation period of 6 months to 3 1/2 years. The PCA-knee endoprosthesis will be described and the special surgical technique will be presented. It's possible to implant the PCA-knee endoprosthesis without cement. 60% of our 184 prostheses were inserted without cement, in 19% it was used partially. In 29 of our cases an implantation was performed in both knees at one stage. The PCA-knee-joint is not constrained. It was necessary to perform corrections of the active and passive knee-stabilisators in 28%, a lateral release was performed in 85%. The postoperative flexion reached on an average 95 degrees (+/- 16.7), the deficit of extension 2 degrees (+/- 4) in opposition to 11 degrees (+/- 9) preoperatively. A severe medial instability of ligaments was found postoperatively just in one case, a slight one in 11 cases and a severe lateral instability in one case. Drawer-instability was found only in 5 patients (3 anterior, 2 posterior). 70% of our patients with an average age of 74 years were able to walk postoperatively more than one kilometre (preoperatively 8%) and more than 50% walked without crutches. Postoperative infections occurred in three cases (1.5%), requiring an arthrodesis, a revision and a withdrawal. No complications arose in 86.5%, the most common was found at the patella (9.5%). Based on increasing experiences this complication could also be almost eliminated. We estimate the implantation of the PCA-knee endoprosthesis as recommandable taking care of correct indication and a careful surgical technique.
PROBLEM: Periprosthetic bone atrophy caused by stress shielding is one of the problems of non-cemented femoral stems of hip arthroplasty. Stress shielding and thus the loss of bone mass and their dissemination in the proximal part of the femur of conventional non-cemented femoral stems depends on stiffness (E-modules of the material and the geometry) of the implant and on the bonding between implant and bone. All currently implanted non-cemented femoral stems lead to proximal bone loss which goes up to 40-50% of the original bone mineral content. The senior author (E. M.) developed a femoral stem (Press Fit-Gliding Stem PFGS) which shifts relative movements of force-transmission from the bone-implant interface into the interior of the prosthetic system (Inner Bearing-System) and which only transfers forces proximal into the femur. METHOD: The examinations were made in 21 patients between 1 and 6 years after implantation of a Press Fit-Gliding Stem compared with a normal contralateral femur (12), with bilateral PFGS (3) and other bilateral arthroplasty (6). RESULTS: In all 21 patients supplied with a PFGS an increase of bone mineral content (BMC) and bone mineral density (BMC) in zone 7 as well as a marked smaller deviation around the mean value in all zones respectively could be noticed. CONCLUSIONS: With the Dual Energy X-ray Absorptiometry (DEXA)-measurement of bone mineral content (BMC) and bone mineral density (BMD) in all zones according to Gruen could be shown that it is not only possible with regard to a favorable force transmission to avoid the inevitable bone atrophy but on the contrary to induce an increase of bone at the point of local force transmission that is in the region of the calcar femorale (zone 7). CLINICAL RELEVANCE: The Press Fit-Gliding Stem is still in the clinical test-program.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
62 patients with infected hip joints whose treatment was started between January 1980 and December 1986 were analysed retrospectively in December 1992 with a mean observation period of 7.2 years (range 1-13). The treatments employed were debridement with lavage drainage in 6 cases, one-stage replacement of the prosthesis on 47 occasions and two-stage replacement in 27 cases. On 5 occasions the prosthesis was removed and a Girdlestone procedure was undertaken. In the 47 one-stage replacements primary intervention was successful in 57% (n = 27), in the two-stage replacements in 74% (n = 20). In 42 cemented shafts there was primary healing in 34, i.e. 81%, compared with 13 (65%) in the 20 non-cemented shafts. Successful healing was finally achieved in all 62 infected hips.
Because they show fairly good short- and mid-term results frozen, morselized homologous bone grafts have become very popular in acetabular reconstruction after failed total hip arthroplasty. Graft integration proceeds uneventfully. However, very little is known about its longevity. From 1980 to 1984 we performed 121 acetabular revisions in cases with contained bone defects utilizing homologous bone graft and a cementless non-coated or hydroxyapatite coated HDPE cup. At the end of 1991 (7 to 11 years after the operation), 43 patients (35%) were available for review. 41 patients (34% had died, 19 patients (16%) were lost to follow-up. In 18 patients (15%), the cups had been revised because of aseptic loosening. The Harris Hip Score showed 50% good to excellent results. Cups inserted after grafting of cystic defects showed almost no migration. However when cavity defects were filled with large bone grafts (n = 23), slow continuous cup migration and progressive graft resorption over time was observed. Due to this continuous resorption, we conclude, that morselized bone grafts do not guarantee an ever lasting inert interface. Once the non-coated HDPE cup is in contact with the autogenous host bed, bone osteolysis occurs and loosening proceeds. Cementless porous coated cups with morselized allografts alone may be used in acetabular revision only when cystic defects are present. The surface of the cup has to be brought into contact with a well vascularized autochthonous pelvic bone in order to achieve stable fixation. Segmental and massive cavity defects can only be reconstructed with morselized allografts when protected from loading by supporting rings.(ABSTRACT TRUNCATED AT 250 WORDS)
Resection arthroplasty should nowadays be considered as obsolete for the following reasons: the removal of the implant and adequate antibiotic therapy can clear the infection. From this point of view the reimplantation of an endoprosthesis is possible. "Deficient bone stock" is not a contraindication to the reimplantation since there are surgical means available to replace bone stock. The results of revision arthroplasty (reimplantation) are incomparably better today that they were years ago (cement-free technique, bone replacement, supports of the acetabulum, special revision prostheses etc.
1. Infected hip arthroplasties can be successfully managed with the appropriate surgical treatment and a long-term antimicrobial therapy. 2. The type of surgical treatment must be based on considerations of various prognostic indications such as the infective agent, the duration of the infection, the stability of the implant component, and the quality of the bone stock and the soft tissue. 3. The majority of infections in artificial hip joints occur by direct inoculation during surgery or by contamination of a local hematoma that arose after surgery.