Mesenchymal stem cells (MSCs) are self-renewing, multipotent cells that could potentially be used to repair injured cartilage in diseases. The objetive was to analyze different sources of human MSCs to find a suitable alternative source for the isolation of MSCs with high chondrogenic potential.

Femoral bone marrow, adipose tissue from articular and subcutaneous locations (hip, knee, hand, ankle and elbow) were obtained from 35 patients who undewent different types of orthopedic surgery (21 women, mean age 69.83 ± 13.93 (range 38–91) years. Neoplasic and immunocompromised patients were refused. The Ethical Committee for Clinical Research of the Government of Aragón (CEICA) approved the study and all patients provided informed consent. Cells were conjugated wiith monoclonal antibodies. Cell fluorescence was evaluated by flow cytometry using a FACSCalibur flow cytometer and analysed using CellQuest software (Becton Dickinson). Chondrogenic differentiation of human MSCs from the various tissues at P1 and P3 was induced in a 30-day micropellet culture [Pittenger et al., 1999]. To evaluate the differentiation of cartilaginous pellet cultures, samples were fixed embedded in paraffin and cut into 5- υm-thick slices. The slices were treated with hematoxylin-eosin and safranin O (Sigma-Aldrich). Each sample was graded according to the Bern Histological Grading Scale [Grogan et al., 2006], which is a visual scale that incorporates three parameters indicative of cartilage quality: uniform and dark staining with safranin O, cell density or extent of matrix produced and cellular morphology (overall score 0–9). Stained sections were evaluated and graded by two different researchers under a BX41 dual viewer microscope or a Nikon TE2000-E inverted microscope with the NIS-Elements software. Statistics were calculated using bivariate analysis. Pearson's χ2 or Fisher's exact tests were used to compare the Bern Scores of various tissues. To evaluate the cell proliferation, surface marker expression and tissue type results, ANOVA or Kruskal-Wallis tests were used, depending on the data distribution. Results were considered to be significant when p was < 0.05.

MSCs from all tissues analysed had a fibroblastic morphology, but their rates of proliferation varied. Subcutaneous fat derived MSCs proliferated faster than bone marrow. MSCs from Hoffa fat, hip and knee subcutaneous proliferated slower than MSCs from elbow, ankle and hand subcutaneous. Flow cytometry: most of cells lacked expression of CD31, CD34, CD36, CD117 (c-kit), CD133/1 and HLA-DR. At same time 95% of cells expressed CD13, CD44, CD59, CD73, CD90, CD105, CD151 y CD166. Fenotype showed no differences in cells from different anatomic places. Cells from hip and knee subcutaneous showed a worst differentiation to hyaline cartilage. Hoffa fat cells showed high capacity in transforming to hyaline cartilage.

Cells from different anatomic places show different chondrogenic potential that has to be considered to choose the cells source.

NK cells participate in the control of infection and cell transformation but, on the other hand, they are involved in the pathology of different inflammatory disorders. Recent evidences suggest that inflammation is an important regulator of osteoarthritis, but the mechanism and cells responsible of inflammation maintenance are not well defined.

To understand the role of NK cells in osteoarthritis, we have performed a preliminary study to compare the phenotype and function of peripheral blood with synovial fluid NK cells from 49 patients with osteoarthritis undergoing total knee arthroplasty. A phenotype analysis of NK cells were carried out by flow cytometry using lineage surface marker. For the first time, the expression of granzyme A, granzyme B and perforin was also performed. Finally, cytotoxicity assays were carried out using previously isolated NK cells co-cultured with their natural target K562 cells.

The majority of NK cells from the synovial fluid were CD56brightCD16negative cells. Moreover, CD56brightCD16negative cells present in synovial fluid showed higher expression of granzyme A and low expression of granzyme B and perforin. In addition, and in contrast to NK cells isolated from the peripheral blood, synovial NK cells were not able to kill K562 cells.

Our results indicate that NK cells from the synovium of patients with osteoarthritis, which present an immunoregulatory non-cytotoxic phenotype, show a different to phenotype of NK cells from peripheral blood, preferably expressing granzyme A, a pro-inflammatory molecule which may contribute to the establishment of chronic articular inflammation in this type of patients.

Introduction: Use of a variable angle sliding hip screw is an interesting therapeutic option in pathological trauma of the proximal femur. It has successfully been used in cases of loosening of previously implanted hardware and non-union.

Materials and methods: In this study we present 26 cases treated consecutively in our department between 2001 and 2005. The majority of patients in this group had suffered complications in the treatment of proximal femoral fractures, including non-unions and nail cut-outs.

Results: We treated 12 male patients and 14 female patients; mean age was 72 years. Mean hospital stay was 14.3 days. The patients were examined in our consulting offices and had a minimum 6 months follow-up, with controls of their evolution at 3 and 6 months and 1 year. During the study period functional and x-ray assessments were performed. No relevant alterations were found in any of the patients; all cases resolved successfully.

Conclusions: The variable angle sliding hip screw has been successfully used in cases of severe complications in patients with proximal femur fractures. We have tried to summarize our 4 years’ experience in this study by presenting a series of different cases that went from failure of a previous osteosynthesis to other techniques applied to the fracture failure such as the use of autologous grafts to resolve non-unions. The variable angle sliding hip screw is a very useful and versatile tool in the hands of the orthopedic surgeon in certain cases where rescue surgery is necessary.

Introduction and Objectives: The goal of this study is to present results from a series of arthroplasties performed in our hospital in the past 3 years in terms of pain and mobility.

Materials and Methods: In this study, a total of 14 arthroplasties were performed on 12 patients (including 2 revisions). Follow-up was lost on 3 patients. Of the 9 remaining patients, 5 were females and 4 were male. Average age was 59 years (42–75) at time of surgery. Two prosthetic models were used: Coonrad-Morrey in 5 cases (including one revision) and GSB-III in 6 cases (including one revision). The following conditions were treated: 5 cases of post-traumatic arthrosis of the elbow, one haemophilic arthropathy of the elbow with the elbow as the target joint, one case of rheumatoid arthritis, one supracondylar fracture with nonunion in an elderly patient, and one humeral fracture with post-traumatic arthrosis of the elbow.

Results: At the functional level, a postoperative articular balance of 118° flexion and −20° extension and free pronosupination was obtained, with the exception of 2 cases. There was complete elimination or a significant decrease in pain except in 2 cases where a certain level of pain persisted. Radiographically, poor positioning was not seen, but there was one case of septic loosening (resulting in resective arthroplasty) and one peri-prosthetic fracture requiring revision, since it led to instability and repeated dislocation. Other complications included neurologic problems (2), extension deficit > 30° (2), and residual pain (2).

Discussion and Conclusions: Although this study is still in the early stages and follow-up time is short (the study was initiated in 2000), we are seeing promising results in terms of mobility and cessation of pain, similar to various other studies. In terms of the percentage of revisions, complications, and patient satisfaction, results are also comparable to other studies, even though our study thus far has the disadvantage of being shorter. Nonetheless, we wish to present this study to demonstrate that even though elbow arthroplasties are in their infancy, results are promising, and there is hope that they will improve further in future with improved selection criteria, as happened in the past with knee and hip arthroplasties.