Introduction

Standard surgical exposure reduces blood flow to the patella during total knee arthroplasty (TKA). Reduction of patellar blood flow has resulted in patellofemoral complications including osteonecrosis and patellar fracture, necessitating revision surgery. Eversion of the patella is typically used to gain access to the knee joint in most TKA surgical approaches. More recently, the development of minimally invasive surgery (MIS) techniques has avoided patellar eversion by subluxing the patella. The present study is the first to measure patellar blood flow during MIS TKA with the knee in both extension and 90 degrees of flexion followed by lateral retraction and then eversion of the patella.

Osteoporosis is one of the most common diseases in modern aging society. Receptor activator of nuclear factor-κB ligand (RANKL) plus macrophage colony stimulating factor (M-CSF)-mediated osteoclastogenesis has been recently implicated in the pathogenesis of this disease. Among other causes, the anticoagulant drug heparin is a notable inducer of secondary osteoporosis, although the molecular pathway underlying this process, particularly in human model, has not been clarified yet. Recently, we reported the differentiation of two subtypes of osteoclasts starting from human peripheral blood CD14-positive monocytes (Monocytes), respectively fusion regulatory protein-1 (FRP-1/CD98)-mediated osteoclasts and RANKL+M-CSF-mediated osteoclasts. We, therefore, investigated in details effects of heparin on differentiation and activation using a simple system of human osteoclastogenesis.

When Monocytes were cultured with osteoclastogenesis-relating factors and a high dose of heparin, heparin suppressed osteoclastogenesis in both pathways. However, a proper quantity of heparin enhanced tartrate-resistant acid phosphatase-positive multinucleated giant cell formation. There were significant differences in fusion indices between control osteoclasts and osteoclasts stimulated by moderate concentrations of heparin in two systems (P< 0.05). As a result of osteoclastic activity, FRP-1-mediated osteoclasts treated with a proper quantity of heparin formed larger pits on Ca plates. Moreover, lacunae on dentin surfaces induced by FRP-1-mediated osteoclasts were enhanced with moderate concentration of heparin. In contrast, heparin did not increase pit-formation area on Ca plates and on dentin surfaces by RANKL+M-CSF-mediated osteoclasts. Evaluating the relation between the concentration of heparin and the osteolytic areas on Ca plates, Pearson’s correlation coefficient of the FRP-1 and the RANKL+M-CSF were −0.973 (P< 0.05) and −0.695 (P=0.19), respectively.

In present study, although moderate doses of heparin stimulated differentiation in both systems, in osteoclastic activity, heparin promoted only to the FRP-1 system, not to RANKL+M-CSF system. Our results suggested FRP-1-induced osteoclastogenesis mainly contributes to development of heparin osteoporosis and also that the onset mechanism after long-term administration of heparin may be affected by the characteristic bone resorption ability of FRP-1osteoclasts.

Introduction: The purpose of this study was to speculate the process of degenerative changes in the lumbar spine.

Methods: The subjects were 80 (45 men and 35 women) patients aged 39–92 years (mean, 67.2 years) with degenerative change of the facet joints who had undergone surgery. These patients were divided between two groups using Gibson’s classification in T2-weighted MR images at L4-5 or L5-S1. The patients with 3 or 4 grade were regarded as D(+); otherwise as D(−). The number of patients, age, gender and the presence or absence of painful arthrosis in the limbs in each group were examined.

Results: There were 47 (20 men, 27 women) patients with a mean age of 67.5 years in the D(+) group, 33 patients (25 men, 8 women; mean age, 66.6) in the D(−) group. Painful arthrosis in the limbs was more often observed in the D(−) group than in the D(+) groups.

Conclusion: In the process of degenerative change of facet joints, some patients did not have severe disc degeneration. Most patients in the D(−) group were men and had painful arthrosis in the limbs.

Antibiotic-impregnated polymethylmethacrylate beads, which are used to deliver antibiotic directly to infected sites in the musculoskeletal system has been evaluated most widely. The disadvantages include reduced biocompatibility with bone, short duration of drug release, very low release rate and thermal damage to the antibiotics. For solving this problem, we developed the antibiotic-impregnated calcium hydroxyapatite ceramic implant (HA) as a new drug delivery system. This study is to evaluate the clinical results of the antibiotic-impregnated HA used for the treatment of infected total hip and knee arthroplasty. Twenty-two patients with infected arthroplasty treated antibiotic-impregnated HA were evaluated. There were 5 men and 17 women with a median age of 65 (range, 54–86 years). The study included 14 hips and 8 knees. The duration from the initial arthroplasty to the detection of the infection was 16 years at the longest (median of 2 years and 2 months). The most common microorganism was Staphylococcus aureus, presented in 13 patients. Antibiotic most frequently impregnated was Vancomycin. In five patients, debridement without removal of the prosthesis was performed with antibiotic-impregnated HA implanted in surrounding bone. In another three patients, one-stage revision was performed with antibiotic-impregnated HA. In fourteen patients, antibiotic-impregnated HA was used to fill the dead space after removal of the prosthesis (two-stage revision was performed in 9 patients). No patients developed evidence of recurrent infection at an average follow-up of 18.7 months. Antibiotic-impregnated HA is an excellent drug delivery system for the infected total hip and knee arthroplasty.