No abstract

Malnutrition has been often suggested as contributing to both the high incidence of hip fracture in elderly people and its complications. In a recent prospective controlled randomized study, the clinical outcome of elderly patients with osteoporotic fracture of the proximal femur (hip fracture) improved by giving a simple oral dietary supplement. This study, however, did not prove that protein was responsible for the clinical improvement since the supplement also contained vitamins and minerals. We addressed this question by comparing the clinical outcome and bone mineral density (BMD) changes in elderly patients with hip fracture, receiving two different dietary supplements with different protein contents. Sixty-two patients (mean age 82) admitted into the orthopedic ward for fracture of the proximal femur were randomized into two groups. One group (n = 33) received 250 ml/day of an oral nutritional supplement containing protein (20.4 g), mineral salts (Ca: 0.525 g) and vitamins A = 750 IU; D3 = 25 IU) for a mean of 38 days. A control group (n = 29) received the same supplement dose, but with no protein, for the same period of time. The clinical course was significantly better in the group receiving protein, with 79% having a favorable course as compared to 36% (p less than 0.02) in the control group during the stay in the recovery hospital. The rate of complications and deaths was also significantly lower in the protein-supplemented vs the control group (52 vs 80%, p less than 0.05) 7 months after hip fracture. The median hospital stay was significantly lower in the protein-supplemented group (69 vs 102 days, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

The efficacy of calcium (Ca) in reducing bone loss is debated. In a randomized placebo-controlled double-masked study, we investigated the effects of oral Ca supplements on femoral shaft (FS), femoral neck (FN) and lumbar spine (LS) bone mineral density (BMD), and on the incidence of vertebral fracture in vitamin-D-replete elderly. Ninety-three healthy subjects (72.1 +/- 0.6 years) were randomly allocated to three groups receiving 800 mg/day Ca in two different forms or a placebo for 18 months. Sixty-three patients (78.4 +/- 1.0 years) with a recent hip fracture were allocated to two groups receiving the two forms of Ca without placebo. FS BMD changes in Ca-supplemented non-fractured women were significantly different from those in the placebo group (+0.6 +/- 0.5% v -1.2 +/- 0.7%, p < 0.05). There was no difference in effect between the two forms of Ca. The changes of +0.7 +/- 0.8% v -1.7 +/- 1.6% in FN BMD of Ca-supplemented women and the placebo group did not reach statistical significance. In fractured patients, FS, FN and LS BMD changes were -1.3 +/- 0.8, +0.3 +/- 1.6 and +3.1 +/- 1.2% (p < 0.05 for the last). The rate of new vertebral fractures was 74.3 and 106.2 fractures per 1000 patient-years in Ca-supplemented non-fractured subjects and in the placebo group, respectively, and 144.0 in Ca-supplemented fractured patients. Thus, oral Ca supplements prevented a femoral BMD decrease and lowered vertebral fracture rate in the elderly.

A prospective survey of hip fracture incidence and outcome was conducted to evaluate their socioeconomic impact. Over the course of 1 year, 404 hip fractures were recorded in 339 women and 65 men following minor or moderate trauma. The subjects' ages were 82.8 +/- 10.0 years (mean +/- SD): 84.1 +/- 9.2 in female and 76.4 +/- 13.7 in male subjects. The overall annual incidence was 104.4/100,000; the incidence in women was 167.1 versus 35.3 in men, with a crude female-to-male ratio of 4.7. However, when adjusted for age, this ratio was 2.7. When adjusted to the 1985 U.S.A. population, the incidence rates were 68.6 overall, 108.8 female, and 26.3 male, and were, respectively, 119.1, 188.8, and 46.1 when adjusted to the 1992 Swiss population. As compared with 105 age-matched non-hip-fracture fallers studied in the same emergency ward, fracture subjects lived more often in nursing homes and took cardiovascular drugs (p < 0.001). The mean length of stay in the orthopedic ward was 16.3 +/- 12.0 days (median 14; range 2-193 days), for a total of 6566 bed-days representing 19.8% of available bed-days. The mean length of stay in rehabilitation hospitals was 63.6 +/- 52.6 days (median 50; range 2-349 days), for a total of 17,099 bed-days, representing 5.2% of available bed-days. For patients who where independent before fracture, the greater length of stay was associated with advanced age and consumption of cardiovascular drugs. The total cost of hospital stay amounted to approximately $44,000 per patient. Mortality was 3.2% in the orthopedic ward and 10.8% in rehabilitation hospitals, for an overall in-hospital mortality rate of 10.4%. Overall, the 1-year mortality was 23.8% (21.5% for women and 35.4% for men), and it was significantly higher than in the general population (p < 0.001). Prognostic factors for mortality were age, sex, consumption of cardiovascular drugs, and previous living circumstances. One year after fracture, 62.6% of the fracture patients had returned to their previous living circumstances, but 17.9% needed a more care-intensive environment. The likelihood of returning to autonomous living circumstances 1 year after fracture was higher in younger subjects, in females, in those living with a partner, and in those in overall better health before the fracture. This prospective survey highlights the high socioeconomic impact and burden of osteoporotic fractures of the proximal femur.

No abstract

Staphylococcal infection of various prosthetic and internal fixation devices is a major complication associated with orthopaedic surgery. This study investigated the role of the host protein fibronectin in promoting adhesion of Staphylococcus aureus and Staphylococcus epidermidis to metallic surfaces representing materials used for orthopaedic devices. Pure human fibronectin was adsorbed in vitro onto coverslips (0.8 x 0.8 cm) of stainless steel, pure titanium, or titanium-aluminum-niobium alloy. In vitro bacterial adhesion was promoted more strongly by the metallic surfaces coated with fibronectin than by albumin-coated controls for two strains of S. aureus and one strain of S. epidermidis. Furthermore, with the fibronectin-coated coverslips, bacterial adhesion to titanium alloy was significantly greater than adhesion to stainless steel. Adhesion of the three staphylococcal strains was promoted more strongly by coverslips explanted from the subcutaneous space of guinea pigs and tested under similar conditions than by albumin-coated controls. Incubation of either in vitro fibronectin-coated or explanted metallic coverslips with anti-fibronectin antibodies produced a significant decrease in staphylococcal adhesion. These results suggest that the presence of fibronectin on the surface of implanted metallic devices is an important determinant of colonization of orthopaedic biomaterials by staphylococci.

Bone mass is an important determinant of resistance to fractures. Whether bone mineral density (BMD) in subjects with a fracture of the proximal femur (hip fracture) is different from that of age-matched controls is still debated. We measured BMD of the femoral neck (FN) on the opposite side to the fracture, as well as femoral shaft (FS) and lumbar spine (LS) BMD by dual-photon absorptiometry in 68 patients (57 women and 11 men, mean age 78.8 +/- 1.0) 12.4 +/- 0.8 days after hip fracture following a moderate trauma. These values were compared with BMD of 93 non-fractured elderly control subjects (82 women and 11 men), measured during the same period. As compared with the controls, FN BMD was significantly lower in fractured women (0.592 +/- 0.013 v. 0.728 +/- 0.014 g/cm2, P less than 0.001) and in fractured men (0.697 +/- 0.029 v. 0.840 +/- 0.052, P less than 0.05). Expressed as standard deviations above or below the mean BMD of age and sex-matched normal subjects (Z-score), the difference in FN BMD between fractured women and controls was highly significant (-0.6 +/- 0.1 v. +0.1 +/- 0.1, P less than 0.001). As compared with mean BMD of young normal subjects, BMD was decreased by 36.9 +/- 1.4 and 22.4 +/- 1.5% (P less than 0.001) in fractured and control women, respectively. There was no significant difference between FN BMD of 33 women with cervical and 24 with trochanteric hip fractures (0.603 +/- 0.017 v. 0.577 +/- 0.020). FN BMD was lower than 0.705 g/cm2 in 90% of fractured women.(ABSTRACT TRUNCATED AT 250 WORDS)

Infection around metallic implants is a rare but severe complication of orthopaedic surgery. A novel animal model mimicking conditions of internal fixation devices was developed to evaluate the role of host proteins adsorbed on metallic devices in promoting adhesion and colonization of the material surfaces by Staphylococcus aureus. Small plates made of pure titanium were either fixed (three screws per plate) onto the iliac bones of guinea pigs or implanted into their subcutaneous space as controls. Five to 6 weeks after surgery, the plates and screws were removed from the previously killed animals, carefully rinsed in buffer, and tested in an in vitro assay of S. aureus adhesion to metallic surfaces. To evaluate the role of fibronectin in staphylococcal adhesion to explanted plates and screws, a mutant of S. aureus that is specifically defictive in fibronectin adhesion due to decreased expression of the fibronectin adhesin was compared with its isogenic parental strain. A significant reduction in adhesion of the fibronectin adhesin-defective mutant compared with the parental strain occurred on both the subcutaneously implanted and bone-implanted metallic plates. The results of this specific biological assay suggest that fibronectin is present on bone-implanted metallic devices and promotes attachment of S. aureus to their surfaces. This novel experimental model should help, to characterize several parameters of bacterial adhesion to metallic orthopaedic devices and to develop novel anti-adhesive strategies for preventing such infections.