Impregnation of bone chips with alendronate and cefazolin, combined with demineralized bone matrix: a bone chamber study in goats.

BACKGROUND: Bone grafts from bone banks might be mixed with bisphosphonates to inhibit the osteoclastic response. This inhibition prevents the osteoclasts to resorb the allograft bone before new bone has been formed by the osteoblasts, which might prevent instability. Since bisphosphonates may not only inhibit osteoclasts, but also osteoblasts and thus bone formation, we studied different bisphosphonate concentrations combined with allograft bone. We investigated whether locally applied alendronate has an optimum dose with respect to bone resorption and formation. Further, we questioned whether the addition of demineralized bone matrix (DBM), would stimulate bone formation. Finally, we studied the effect of high levels of antibiotics on bone allograft healing, since mixing allograft bone with antibiotics might reduce the infection risk. METHODS: 25 goats received eight bone conduction chambers in the cortical bone of the proximal medial tibia. Five concentrations of alendronate (0, 0.5 mg/mL, 1 mg/mL, 2 mg/mL, and 10 mg/mL) were tested in combination with allograft bone and supplemented with cefazolin (200 µg/mL). Allograft not supplemented with alendronate and cefazolin served as control. In addition, allograft mixed with demineralized bone matrix, with and without alendronate, was tested. After 12 weeks, graft bone area and new bone area were determined with manual point counting. RESULTS: Graft resorption decreased significantly (p < 0.001) with increasing alendronate concentration. The area of new bone in the 1 mg/mL alendronate group was significantly (p = 0.002) higher when compared to the 10 mg/mL group. No differences could be observed between the group without alendronate, but with demineralized bone, and the control groups. CONCLUSIONS: A dose-response relationship for local application of alendronate has been shown in this study. Most new bone was present at 1 mg/mL alendronate. Local application of cefazolin had no effect on bone remodelling.

Traction force for peroperative hip dislocation in hip arthroscopy.

OBJECTIVES: Traction force widens the joint space during hip arthroscopy. It is unclear how much the traction force varies and if it is related to the joint space widening. Main goal of our study was to measure the amount of force needed to widen the hip joint. Second goal was to study the relation between this force and the amount of joint space widening. METHODS: Traction force was measured in 27 patients (of whom 24 female, mean age 41) during arthroscopy. Measurements were performed before the procedure, after vacuum seal release and after capsulotomy. Joint space widening was measured with fluoroscopy and was calibrated. Friedman and Wilcoxon tests were used to measure differences in traction. The Spearman's rho correlation coefficient was used to identify a correlation in traction force and joint space widening. Regression analyses were used to identify relations between age, body mass index (BMI), hip degeneration and traction force. RESULTS: The median traction force before arthroscopy was 714 N, lowered to 520 N after vacuum seal release and to 473 N after capsulotomy (p < 0.001). Median joint space widening was 8.8 mm. Spearmans' rho correlation between traction force and joint space widening was ‒0.13. DISCUSSION: Median traction force of 714 N resulted in 8.8 mm of joint space widening. This traction force was significantly lowered by 200 N after release of the vacuum seal of the hip and 250 N after additional capsulotomy without loss of joint space narrowing. No significant relation was identified for age, BMI or progression of the Kellgren-Lawrence classification for hip degeneration and traction force. Netherlands Trial Registry number 8610.

Less than one-third of hip fracture patients return to their prefracture level of instrumental activities of daily living in a prospective cohort study of 480 patients.

AIM: A significant loss of instrumental activities of daily living (IADL) after a hip fracture has been reported. The aim of the present study was to identify specific predictors for low IADL after a hip fracture, in order to target better postoperative care for these patients. METHODS: A prospective observational cohort study of 480 hip fracture patients was carried out. IADL was measured at baseline, and after 3 and 12 months using the Groningen Activity Restriction Scale. Multivariable logistic regression analysis was carried out using age, sex, American Society of Anesthesiologists classification, prefracture living with a partner, prefracture living situation, prefracture use of walking aids, type of fracture, type of anesthesia, length of hospital stay, postoperative complications and prefracture IADL as potential predictors for low IADL after a hip fracture. The correlation between IADL, mobility and living situation, both at admission, and 3 and 12 months postoperatively, were measured. RESULTS: Three months after hip fracture treatment, 24% of patients returned to their baseline IADL level, at 12 months postoperative this was 29%. Factors associated with a larger loss in IADL after a hip fracture were older age, prefracture living with a partner, prefracture living at home, prefracture use of walking aids and longer length of hospital stay. The correlation between IADL and living situation was 0.69, and between IADL and use of walking aids was 0.80. CONCLUSIONS: A return to prefracture IADL level was low. Healthier patients have a steeper decline in postoperative IADL. Geriatr Gerontol Int 2018; 18: 1244-1248.