Archives of orthopaedic and trauma surgery
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Arch Orthop Trauma Surg · Jan 1999
Shear strength of the cement metal interface--an experimental study.
The shear strength of the cement-metal interface using rods with different surface treatments and a clinical standardized cementing technique was studied. Under "dry" conditions, a low interface shear strength can be obtained with polished and smooth CoCrMo surfaces (peak-to-valley height Rt: 1 microm, average 0.2 MPa; 5 microm, 0.38 MPa). Grit-blasted and polymethylmethacrylate (PMMA)-precoated surfaces achieved higher values (PMMA precoat: average 5.16 MPa; CoCrMo peak-to-valley height Rt: 20 microm, average 8.61 MPa: 60 microm, average 7.8 MPa). ⋯ A microscopic analysis of cross-sections revealed gap formations at the cement-metal interface to varying degrees (1-16 microm). PMMA-precoated rods rarely showed any gap formation at all. The above-mentioned gap formation was seen independently of the porosity at the cement-metal interface and corresponds to the clinical and postmortem observed debonding of the interface.
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Arch Orthop Trauma Surg · Jan 1999
Postoperative ossifications of the shoulder. Incidence and clinical impact.
Periarticular ossifications of the shoulder after surgery have been described since the beginning of the century. Risk factors and the clinical impact of heterotopic bone formation have been discussed controversially. After open surgery on the shoulder, 131 patients (rotator cuff repair n = 106, acromioplasty n = 25) were included in a retrospective study if pre- and postoperative X-rays were available. ⋯ As significant risk factors for the formation of heterotopic bone, the existence of osteoarthritis and the duration and complexity of the procedure could be cited. The appearance of periarticular ossifications after surgery of the shoulder seems to be of minor clinical impact. Severe cases with major functional deficits should and can be prevented by a fast and atraumatic operation technique.
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Arch Orthop Trauma Surg · Jan 1999
Comparative StudyRevascularization and new bone formation in heat-treated bone grafts.
Human imnmunodeficiency virus (HIV) infection is one of the possible serious complications associated with bone allografts. In order to prevent infection, grafted bone is sterilized by various treatments. Heat treatment has attracted attention as a simple and practical method. ⋯ The grafts heat-treated at 80 degrees C showed relatively good revascularization and new bone formation. However, the grafts heat-treated at 100 degrees C showed unsatisfactory revascularization and bone formation, less than 40% of control 8 weeks after grafting. Therefore, heat treatment at 60-80 degrees C does not seriously affect revascularization and new bone formation.