Predictive value of Singh index and bone mineral density measured by quantitative computed tomography in determining the local cancellous bone quality of the proximal femur.

OBJECTIVE: The purpose of this study was to assess the predictive value of the Singh index as well as quantitative computed tomography for the in vitro local mechanical competence of the cancellous bone of the proximal femur. DESIGN: An experimental study examining the relation between mechanical properties and bone mineral density of the femoral neck determined in vitro and the clinical estimated Singh index on X-rays. BACKGROUND: Evaluation of the predictive value of the Singh index, an inexpensive and simple technique for the mechanical properties of the cancellous bone of the proximal femur. METHODS: The bone quality of the proximal femur of 34 patients undergoing total hip replacement was estimated by roentgenography using the Singh index. Bone mineral density was quantified by quantitative computed tomography using cylindrical cancellous bone biopsies harvested during the total hip replacement procedure by a new biopsy method. The mechanical properties of the bone specimens (Young's modulus, strength and maximum energy absorption E(max)) were measured by mechanical testing of the bone biopsies. RESULTS: A strong correlation of the Singh index versus material properties of cancellous bone was noted (r=0.66 for Young's modulus, r=0.73 for strength and r=0.69 for E(max), P<0.0001). The correlations of bone mineral density measured by quantitative computed tomography versus Young's modulus, strength and energy absorption E(max) were significant. Strength was predicted best (r=0.82; P<0.0001), followed by E(max) (r=0.79; P<0.0001) and Young's Modulus (r=0.73; P<0.0001). CONCLUSIONS: We conclude, that assessment of bone mineral density by quantitative computed tomography is a reliable and precise method for the estimation of cancellous bone material properties. The Singh index provides a rough estimate for the mechanical competence of the proximal femur. It is inexpensive, simply to assess and can in some cases replace the measurement of bone mineral density, notably in cases of marked decrease in bone density.

[Fractures of the upper extremity in the elderly]. / Frakturen der oberen Extremität beim alten Menschen.

PROBLEM: The primary goal in treating fractures in elderly persons is safe and rapid restoration of their functional capabilities to secure independence in everyday activities. The intention of this paper is to present an overview of treatment principles useful in this age group. METHODS: We analysed a series of 404 patients above the age of 70 years who underwent surgery for fractures of the arm between 1981 and 1997. RESULTS: Diaphyseal fractures are less frequent in this age group and their treatment does not differ significantly from principles established for younger patients. The majority of fractures of the proximal humerus and the distal radius can be treated by conservative means. Unstable fractures are frequent in the distal humerus and the olecranon requiring operative reduction and osteosynthesis. CONCLUSIONS: Preferred operative techniques in aged persons inflict minimal surgical trauma and have a low rate of complications and secondary interventions. In contrast, anatomical reconstruction has the highest priority in younger individuals.

[Acetabular fractures in elderly persons. Primary endoprosthetic treatment]. / Acetabulumfraktur beim alten Menschen. Primäre endoprothetische Versorgung.

In the Department of Traumatology at the University of Ulm, 26 elderly patients with displaced acetabular fractures were treated with primary implantation of a hip joint endoprosthesis between 1986 and 1996. The principles of operative therapy are stabilization of the acetabular ring, grafting of acetabular defects with autogenous corticocancellous bone and cranial buttressing with a reinforcing ring. This concept permits immediate mobilization of elderly patients and full weight-bearing and thus results in favorable early postoperative results. Secondary complications typically caused by immobilization can therefore be avoided.

[Prosthetic humeral head replacement in dislocated humerus multi-fragment fracture in the elderly--an alternative to minimal osteosynthesis?]. / Der prothetische Humeruskopfersatz bei der dislozierten Humerusmehrfragmentfraktur des alten Menschen--Eine Alternative zur Minimalosteosynthese?

In a prospective randomised study, comprising 30 aged patients with fractures of the proximal humerus (4-fragment fractures according to Neer) minimal osteosynthesis was compared to primary endoprosthetic replacement. The Constant score was used for evaluation during follow-up. After one year the results were similar in both groups. There were two complications necessitating revision surgery among the patients with minimal osteosynthesis and in four cases the implants had to be removed. In the group with primary endoprosthetic repair neither complications nor revision surgery occurred. Primary endoprosthetic replacement for the treatment of proximal humeral fractures appears as a therapeutic option with a low complication rate and a satisfying functional outcome. In older patients we need a safe mode of therapy permitting early mobilization and quick discharge from the hospital back to the patient's home. Endoprosthetic replacement fulfils these demands since it resembles a "one time surgery" without the risk of revision surgery for implant loosening, pseudarthrosis or ischemic necrosis of the humeral head.

[Acetabular fractures in the elderly - primary endoprosthesis]. / Acetabulumfraktur beim alten Menschen : Primäre endoprothetische Versorgung.

In the Department of Traumatology at the University of Ulm, 26 elderly patients with displaced acetabular fractures were treated with primary implantation of a hip joint endoprosthesis between 1986 and 1996. The principles of operative therapy are stabilization of the acetabular ring, grafting of acetabular defects with autogenous corticocancellous bone and cranial buttressing with a reinforcing ring. This concept permits immediate mobilization of elderly patients and full weight-bearing and thus results in favorable early postoperative results. Secondary complications typically caused by immobilization can therefore be avoided.