Total knee arthroplasty and periprosthetic distal femoral fracture: looking beyond the osteoporosis to previous osteoporotic fracture.

Osteoporosis increases the risk of periprosthetic distal femoral fractures after TKA, especially in patients with a history of osteoporotic fractures. Therefore, careful assessment and proper treatment of osteoporosis need and the importance of taking osteoporotic medication needs to be recognized by the patients following primary TKA. PURPOSE: Osteoporosis is a risk factor for fractures, including those of the hip, vertebrae, and distal radius; however, the association between osteoporosis and periprosthetic fractures after total knee arthroplasty (TKA) has not been much investigated. Therefore, we aimed to investigate the association of the presence of systemic osteoporosis with periprosthetic fractures after TKA. METHODS: This study included 34 patients with periprosthetic fractures following primary TKA and 106 controls matched for age and sex. Bone mineral density was evaluated at the femoral neck, total hip, and lumbar spine using dual X-ray absorptiometry. Medical records were reviewed for age; sex; body mass index; smoking; rheumatoid arthritis, endocrine diseases, and cardiovascular diseases; history of glucocorticoid use; medication for osteoporosis; and history of previous osteoporotic fracture. In addition, anterior femoral notching after TKA was evaluated. Univariable and multivariable logistic regression analysis were used to determine factors associated with periprosthetic fracture. RESULTS: The prevalence of osteoporosis in the fracture group was higher than that in the control group (61.8% vs. 40.6%, p=0.045). The rate of medication for osteoporosis was significantly low in the fracture group (47.6 % vs 76.7%, p=0.026). History of previous osteoporotic fracture (odds ratio [OR], 9.1; p=0.015) and osteoporosis (OR, 3.6; p=0.013) were significant risk factors for periprosthetic fractures after TKA. Medication for osteoporosis could decrease the risk of periprosthetic fracture (OR 0.3; p=0.020). CONCLUSION: Osteoporosis is a major risk factor for periprosthetic distal femoral fractures after TKA. Therefore, careful assessment and proper treatment of osteoporosis need and the importance of taking osteoporotic medication needs to be recognized to the patients following primary TKA, especially in patients with a history of osteoporotic fracture. LEVEL OF EVIDENCE: Prognostic study, level III.

Single-stage cell-based cartilage repair in a rabbit model: cell tracking and in vivo chondrogenesis of human umbilical cord blood-derived mesenchymal stem cells and hyaluronic acid hydrogel composite.

OBJECTIVE: Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) have gained popularity as a promising cell source for regenerative medicine, but limited in vivo studies have reported cartilage repair. In addition, the roles of MSCs in cartilage repair are not well-understood. The purpose of this study was to investigate the feasibility of transplanting hUCB-MSCs and hyaluronic acid (HA) hydrogel composite to repair articular cartilage defects in a rabbit model and determine whether the transplanted cells persisted or disappeared from the defect site. DESIGN: Osteochondral defects were created in the trochlear grooves of the knees. The hUCB-MSCs and HA composite was transplanted into the defect of experimental knees. Control knees were transplanted by HA or left untreated. Animals were sacrificed at 8 and 16 weeks post-transplantation and additionally at 2 and 4 weeks to evaluate the fate of transplanted cells. The repair tissues were evaluated by gross, histological and immunohistochemical analysis. RESULTS: Transplanting hUCB-MSCs and HA composite resulted in overall superior cartilage repair tissue with better quality than HA alone or no treatment. Cellular architecture and collagen arrangement at 16 weeks were similar to those of surrounding normal articular cartilage tissue. Histological scores also revealed that cartilage repair in experimental knees was better than that in control knees. Immunohistochemical analysis with anti-human nuclear antibody confirmed that the transplanted MSCs disappeared gradually over time. CONCLUSION: Transplanting hUCB-MSCs and HA composite promote cartilage repair and interactions between hUCB-MSCs and host cells initiated by paracrine action may play an important role in cartilage repair.

A placebo-controlled randomised trial to assess the effect of TGF-ß1-expressing chondrocytes in patients with arthritis of the knee.

The aim of this study was to assess the effect of injecting genetically engineered chondrocytes expressing transforming growth factor beta 1 (TGF-ß1) into the knees of patients with osteoarthritis. We assessed the resultant function, pain and quality of life. A total of 54 patients (20 men, 34 women) who had a mean age of 58 years (50 to 66) were blinded and randomised (1:1) to receive a single injection of the active treatment or a placebo. We assessed post-treatment function, pain severity, physical function, quality of life and the incidence of treatment-associated adverse events. Patients were followed at four, 12 and 24 weeks after injection. At final follow-up the treatment group had a significantly greater improvement in the mean International Knee Documentation Committee score than the placebo group (16 points; -18 to 49, vs 8 points; -4 to 37, respectively; p = 0.03). The treatment group also had a significantly improved mean visual analogue score at final follow-up (-25; -85 to 34, vs -11 points; -51 to 25, respectively; p = 0.032). Both cohorts showed an improvement in Western Ontario and McMaster Osteoarthritis Index and Knee Injury and Osteoarthritis Outcome Scores, but these differences were not statistically significant. One patient had an anaphylactic reaction to the preservation medium, but recovered within 24 hours. All other adverse events were localised and resolved without further action. This technique may result in improved clinical outcomes, with the aim of slowing the degenerative process, leading to improvements in pain and function. However, imaging and direct observational studies are needed to verify cartilage regeneration. Nevertheless, this study provided a sufficient basis to proceed to further clinical testing.

The correctness of fit of current total knee prostheses compared with intra-operative anthropometric measurements in Korean knees.

We aimed to obtain anthropometric data on Korean knees and to compare these with data on commonly available total knee arthroplasties (TKAs). The dimensions of the femora and tibiae of 1168 knees were measured intra-operatively. The femoral components were found to show a tendency toward mediolateral (ML) under-coverage in small femurs and ML overhang in the large femurs. The ML under-coverage was most prominent for the small prostheses. The ML/anteroposterior (ML/AP) ratio of Korean tibiae was greater than that of tibial components. This study shows that, for different reasons, current TKAs do not provide a reasonable fit for small or large Korean knees, and that the 'gender-specific' and 'stature-specific' components help for large Korean femurs but offer less satisfactory fits for small femurs. Specific modifications of prostheses are needed for Asian knees.

Risk factors for treatment failure in patients with prosthetic joint infections.

A retrospective, observational cohort study was conducted to describe the incidence, clinical and microbiological findings and to evaluate risk factors for treatment failure associated with prosthetic joint infections (PJIs). We retrospectively reviewed the medical records of all patients undergoing total knee or total hip prosthesis implantation in our institution between 1994 and 2008. Our institution is a 1950-bed tertiary care university hospital and referral centre. A total of 93 patients with PJIs was identified although only 68 patients had undergone prosthesis implantation at our hospital. The overall infection rate was 0.63%. The most common organisms isolated were Gram positive (76.5%), including meticillin-resistant staphylococci. Two-stage arthroplasty was performed in 48 (51.6%) patients, and debridement and retention of the prosthesis in 34 (36.5%) patients. When 43 patients followed up for more than two years after treatment were included in treatment outcome analysis, the overall treatment failure rate was 41.8% (18/43). Staphylococcus aureus infection was the only clinical variable associated with treatment failure (odds ratio: 11.9; 95% confidence interval: 1.07-133.9; P=0.044), after adjustment for the other variables. In conclusion, S. aureus was the most common pathogen isolated in patients with PJI, and an independent risk factor for treatment failure in patients with PJI.

Risk factors for treatment failure in patients with prosthetic joint infections.

A retrospective, observational cohort study was conducted to describe the incidence, clinical and microbiological findings and to evaluate risk factors for treatment failure associated with prosthetic joint infections (PJIs). We retrospectively reviewed the medical records of all patients undergoing total knee or total hip prosthesis implantation in our institution between 1994 and 2008. Our institution is a 1950-bed tertiary care university hospital and referral centre. A total of 93 patients with PJIs was identified although only 68 patients had undergone prosthesis implantation at our hospital. The overall infection rate was 0.63%. The most common organisms isolated were Gram positive (76.5%), including meticillin-resistant staphylococci. Two-stage arthroplasty was performed in 48 (51.6%) patients, and debridement and retention of the prosthesis in 34 (36.5%) patients. When 43 patients followed up for more than two years after treatment were included in treatment outcome analysis, the overall treatment failure rate was 41.8% (18/43). Staphylococcus aureus infection was the only clinical variable associated with treatment failure (odds ratio: 11.9; 95% confidence interval: 1.07e133.9; P = 0.044), after adjustment for the other variables. In conclusion, S. aureus was the most common pathogen isolated in patients with PJI, and an independent risk factor for treatment failure in patients with PJI.

Comparison between high and low molecular weight hyaluronates in knee osteoarthritis patients: open-label, randomized, multicentre clinical trial.

Efficacy and safety of high and low molecular weight hyaluronates in knee osteoarthritis patients were compared in a randomized, open-label trial. Patients in the high molecular weight hyaluronate group were treated once weekly for 3 weeks and in the low molecular weight group once weekly for 5 weeks. We evaluated weight-bearing pain, degree of flexion, swelling and knee tenderness; frequency and amount of rescue medication; patient and investigator global assessment of pain, and safety over 12 weeks after final injection of study medication. Significant improvements in pain and WOMAC-Likert scores were observed in both groups, but not between groups. Knee joint pain improvement was noted in both groups by patients and investigators during follow-up. Close correlation was observed between patient- and investigator-reported data. There was no significant difference in side-effects between the groups. In conclusion, the efficacy and safety of high and low molecular weight hyaluronate are similar.

Methylation-induced silencing of ASC and the effect of expressed ASC on p53-mediated chemosensitivity in colorectal cancer.

Tumor suppressor p53 is known to play a crucial role in chemosensitivity in colorectal cancer. We previously demonstrated that an apoptosis-associated speck-like protein, ASC, is a p53-target gene which regulates p53-Bax mitochondrial apoptotic pathway. ASC is also known to be a target of methylation-induced gene silencing. An inactivation of ASC might thus cause resistance to chemotherapy, and if this is the case, then the expression of ASC would restore the chemosensitivity. The aim of this study was to clarify this hypothesis. ASC was methylated in 25% of all resected specimens in patients with colorectal cancer; however, ASC methylation did not always correspond to a lack of ASC protein. When expressed in colon cancer cells, in which ASC is absent due to methylation, ASC was found to enhance the chemosensitivity in a p53-dependent manner. In p53-null cells, ASC increased the p53-mediated cell death induced by p53-expressing adenovirus infection. Our data suggest that the methylation-induced silencing of ASC might cause resistance to p53-mediated chemosensitivity in colorectal cancer. The gene introduction of ASC may thus restore such chemosensitivity, and this modality may therefore be a useful new treatment strategy for colorectal cancer.

Mesenchymal stem/progenitor cells developed in cultures from UC blood.

Background Whether umbilical cord blood (UCB) serves as a source of mesenchymal stem/progenitor cells (MSPC) is controversial. MSPC are the best candidates for cellular therapy of orthopedic skeletal tissues. In order to explore the possibility of UCB as a useful source of MSPC, we identified, expanded in culture, and characterized MSPC from UCB harvests on a large scale. Methods Mononuclear cells isolated from UCB harvests (n=411) were cultured in media supplemented with 10% FBS. MSPC-like cells cultured from each UCB harvest were expanded ex vivo by successive subcultivation. UCB harvests with a more than 1000-fold expanding capacity (n=9) were examined for surface Ag phenotypes and in vitro differentiation potentials into osteogenic, chondrogenic and adipogenic lineages. Results Ninety-five out of a total of 411 UCB units (23.1%) generated MSPC-like cells during cultivation. Nine UCB units (2.2%) yielded MSPC with more than 1000-fold expansion capacity. These cells positively expressed MSPC-related Ag, but did not express myeloid, histocompatibility or endothelial Ag. These cells also possessed multiple capacities for osteogenic, chondrogenic and adipogenic differentiation. Discussion Although the incidence of UCB harvests producing MSPC in culture was low, some of them showed a more than 1000-fold expanding capacity, which is enough in cell numbers to be an allogeneic source for cellular therapy. Our results may encourage the use of UCB as an attractive target for allogeneic cellular therapeutic options in tissue engineering.

Percutaneous release of trigger digits.

We describe a safe and easy percutaneous technique for release of trigger finger using a specially designed knife. The A1 pulley is sectioned by a blade which has a hooked end. We released, percutaneously, 185 trigger fingers, including 62 which were locked using this technique. Satisfactory results were achieved in 173 (93.5%). There were no significant complications. We recommend this as a safe and effective outpatient procedure for those patients who have not responded successfully to conservative treatment, have longstanding symptoms or severe triggering.

Posterior trans-septal portal for arthroscopic surgery of the knee joint.

The authors introduce a safe arthroscopic technique of making a portal through the posterior septum of the knee joint, posterior to the posterior cruciate ligament (PCL). This posterior trans-septal portal makes it possible for the arthroscope or the working instruments inserted through the posteromedial portal to reach the posterolateral compartment. With this portal, complete arthroscopic visualization of the posterior compartment and easier arthroscopic procedures for the posterior compartment of the knee joints are possible, including the posterior and posterosuperior aspect of the both femoral condyles, the posterior horns of both menisci, the posterior and inferior portion of the PCL, the posterior meniscofemoral ligament, the posterior septum, and the posterior capsule. We have used this technique in more than 150 knees for arthroscopic total synovectomy for arthritis of various origins, arthroscopic PCL reconstructions, arthroscopic removal of encapsulated loose bodies or tumors located behind the PCL, arthroscopic repairs of tears in the posterior horns of the medial menisci using the all-inside technique, arthroscopic pullout suture fixation of the avulsion fracture of tibial attachment of PCL, and others. No complications such as injuries of the popliteal neurovascular structures have occurred in our experience.

Thymic carcinoid tumor combined with thymoma--neuroendocrine differentiation in thymoma?

A carcinoid tumor of the thymus combined with thymoma in a 62-year-old man is described. The mediastinal tumor had been present for 13 years and was associated with pure red cell aplasia. Carcinoid tumor occupied the central two-thirds of the tumor, consisting of nests and trabeculae of monotonous round cells, which ultrastructurally showed many intracytoplasmic dense-core granules. Typical spindle cell type thymoma surrounded the carcinoid area. Clinico-pathologic findings of this unique case suggested that the carcinoid tumor developed within a preexisting thymoma, illustrating a possibility of neuroendocrine differentiation of thymic epithelial cells.

Dose assessment to inhalation exposure of indoor 222Rn daughters in Korea.

Long-term, average indoor 222Rn concentrations were measured in 12 residential areas by passive CR-39 radon cups. Corresponding equilibrium-equivalent concentration of radon daughters were derived. The resulting effective dose equivalent for the Korean population due to inhalation exposure of this equilibrium-equivalent concentration of radon daughters was then evaluated.