Silver nanoparticles (AgNPs) possess anti-inflammatory activities and have been widely deployed for promoting tissue repair. Here we explored the efficacy of AgNPs on functional recovery after spinal cord injury (SCI). Our data indicated that, in a SCI rat model, local AgNPs delivery could significantly recover locomotor function and exert neuroprotection through reducing of pro-inflammatory M1 survival. Furthermore, in comparison with Raw 264.7-derived M0 and M2, a higher level of AgNPs uptake and more pronounced cytotoxicity were detected in M1. RNA-seq analysis revealed the apoptotic genes in M1 were upregulated by AgNPs, whereas in M0 and M2, pro-apoptotic genes were downregulated and PI3k-Akt pathway signaling pathway was upregulated. Moreover, AgNPs treatment preferentially reduced cell viability of human monocyte-derived M1 comparing to M2, supporting its effect on M1 in human. Overall, our findings reveal AgNPs could suppress M1 activity and imply its therapeutic potential in promoting post-SCI motor recovery.

INTRODUCTION

Loosening is concerned to be the major cause of revision in the artificial prosthesis. Wear debris of UHMWPE dispersed into the implant-bone interface are phagocytosed by macrophages releasing inflammatory cytokines such as TNF-α which leads to osteolysis and loosening eventually. It is known that the size and structure [1] as well as attached substances on particle surface such as endotoxin could affect the amount of cytokines released [2]. An in vivo study using rat femurs showed that the presence of polyethylene particles around implants could result in accumulation of lipopolysaccharide (LPS) from exogenous sources that may affect bone remodeling around implants [3]. It is also reported that LPS is transported throughout the body with lipoproteins or LPS binding proteins [4] and Circulating LPS may originate from local sites of infection or via bloodborne bacteria [5]. In this study, we evaluated the effects of LPS that attached to UHMWPE particle surface by measuring TNF-α released from macrophages.

Objectives

Osteoporosis is a metabolic disease resulting in progressive loss of bone mass as measured by bone mineral density (BMD). Physical exercise has a positive effect on increasing or maintaining BMD in postmenopausal women. The contribution of exercise to the regulation of osteogenesis in osteoblasts remains unclear. We therefore investigated the effect of exercise on osteoblasts in ovariectomized mice.

Introduction: The nonunion rate is higher and loss of reduction is common after reduction and fusion for the higher grades of spondylolisthesis. This is due to fusion bone base deficiency and lack of anterior column support, and can be addressed by supplementing the posterolateral fusion with a posterior lumbar interbody fusion (PLIF).

Materials: All patients had a single disc level degenerative or spondylolytic slip exceeding 25%. Laminectomy and instrumented reduction (VSP or TSRH) was performed. 86 patients underwent posterolateral fusion and 82 underwent the same procedure plus a PLIF (done by tightly impacting bone chips into the disc cavity after a very aggressive discectomy). No fusion cages were used.

Results: Presented as No-PLIF vs. PLIF. Age: 56 vs. 52 years. Male/Female: 14:72 vs. 15:67. Cases with pars fx: 44% vs. 56%. Level of slip (L3-4, L4-5, L5-S1): 9, 59, 18 vs. 4, 60, 18. Iatrogenic neurological injury: none vs. none. Deep infection: 1 vs. none. Nonunion: 9.3% vs. 2.4%. Broken screws: 6 vs. 2. Degree of slip (pre-op to post-op to 2 years): 34% to 11% to 20% vs. 38% to 4% to 8%. Patients that lost reduction: 67% vs. 18%. Disc height gained at 2 years: −0.2 mm vs. 2.3 mm. Subjective back pain score: 3.5 vs. 2.0. Greenough LBOS score: 54 vs. 62. Patients very satisfied: 43% vs. 60%. Cases with adjacent level slip: 4 vs. 4.

Discussion: Spondylolisthesis is commonly treated with a spinal fusion. The goal of surgery is to eliminate motion between the unstable segments, and mechanically it is preferable that the vertebrae fuse in as near anatomic position as possible. It has been shown that the fusion rate decreases with higher degrees of slip, with the spondylolytic types, and with severely degenerated discs. Pedicle screw instrumentation can increase the fusion rate. Reduction of the slip can often be achieved, but it is common to lose the reduction over the course of 1–2 years if only posterolateral fusion is done. Adding an interbody fusion cage can help restore the disc height and widen the intervertebral foramen, but increases complexity, cost, and may actually decrease bone contact area and compression forces. We have found that in grade II and worse slips, pedicle screw fixation alone is not strong enough to maintain reduction of either vertebral alignment or disc height. Adding a chip PLIF appears safe and effective in increasing the union rate and the disc height, and in maintaining reduction in grade II spondylolisthesis. Clinical results are better, the infection rate is not higher. In our hands, there have been no neurological injuries. This study also raises questions about the role and need for interbody fusion cages.

Between March 1990 and May 1991 we performed 85 primary total hip replacements in 74 patients using the Landos Atoll hydroxyapatite (HA)-coated cup and the Corail HA-coated stem. The patients were followed up for a mean of ten years. Of the 85 cups, 26 (31%) have already been revised and a further six are radiologically unstable and awaiting revision. Two femoral stems have been revised for infection without loosening.

The retrieved acetabular cups were studied by SEM and image-processing techniques to quantify the amount of residual HA on the cup. This was correlated with the clinical variables and modes of failure. The residual HA (as a percentage of the surface) on the loose cups correlated negatively with the duration of implantation (r = −0.732, p < 0.001). Six cups were stable at revision and had more residual HA coating than those which were loose (p < 0.01).

The rate of failure of the Landos Atoll HA-coated, smooth hemispherical cup with screw fixation is unacceptably high. Resorption of the HA coating is markedly increased in loose cups compared with stable cups. HA coating cannot substitute for stable mechanical fixation.

The Gamma nail was introduced for the treatment of peritrochanteric fractures with the theoretical advantage of a load-sharing femoral component which could be implanted by a closed procedure. We report a randomised prospective study of 186 fractures treated by either the Gamma nail or a dynamic hip screw. Gamma nails were implanted with significantly shorter screening times, smaller incisions, and less intraoperative bleeding. The Gamma nail group had a shorter convalescence and earlier full weight-bearing, but there was no significant difference in mortality within six months, postoperative mobility, or hip function at review. More intra-operative complications were recorded in the Gamma nail group, mainly due to the mismatching of the femoral component of the nail to the small femurs of Chinese people. Use of a smaller modified nail reduced these complications. We conclude that with careful surgical technique and the modified femoral component, the Gamma nail is an advance in the treatment of peritrochanteric fractures.

The conventional treatment of comminuted fractures in the distal radius has been unsatisfactory. We therefore made a prospective study using the principle of ligamentotoxis and primary cancellous bone grafting as the uniform method of treatment. Ligamentotaxis was maintained by using an external fixator for three weeks only, after which a carefully monitored programme of rehabilitation was given. We have reviewed 72 consecutive distal radial fractures after a follow-up of 7 to 40 months (average 11 months). Reduction had been maintained during healing and over 80% of patients regained full range of movement in hands, wrists and forearms with strong and pain-free wrist function. Complications were infrequent and gave no real problems. We conclude that distraction, external fixation and bone grafting appears to be an excellent method of treating comminuted fractures of the distal radius.