Osteochondral repair using an acellular dermal matrix-pilot in vivo study in a rabbit osteochondral defect model.

The aim of this pilot project was to introduce a novel use of acellular dermal matrix (ADM) in combination with infrapatellar fat pad mesenchymal stromal cells (IPFP-MSCs) to effect repair in a rabbit osteochondral defect model. ADM, in a range of surgical procedures, has been shown to promote remodelling of tissue at the site of implantation. Rabbit-derived ADM (rabADM) was prepared from the skin of donor rabbits. Autologous IPFP-MSCs were obtained at the time of knee surgery. Osteochondral defects (4 mm cartilage outer/2 mm central bone defect) were drilled into distal femoral condyles of 12 New Zealand White rabbits. Treatments groups: (i) defect only; (ii) rabADM alone; (iii) IPFP-MSCs alone; and (iv) rabADM with IPFP-MSCs. Condyles were harvested at 12 weeks, and analyzed using histology, immunohistochemistry (types I and II collagen) and histomorphometry to evaluate osteochondral repair. The rabADM only group achieved the highest ratio of type II to non-type II collagen (77.3%) using areal measures (similar to normal cartilage), which indicated a higher quality of cartilage repair. The addition of IPFP-MSCs, with or without rabADM, formed a fibrous collagen cap above the lesion site not seen with rabADM alone. Macroscopically, there was no joint erosion, inflammation, swelling or deformity, and all animals maintained full range of motion. CONCLUSIONS: RabADM alone resulted in neocartilage formation similar to native cartilage. IPFP-MSCs limited osteochondral repair and contributed to fibrosis, even in combination with the rabADM. Further studies using ADM for osteochondral repair are warranted in a more appropriate pre-clinical model of osteochondral repair. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1919-1928, 2018.

Clinical infections in the noninstitutionalized geriatric age group: methods utilized and incidence of infections. The Pittsburgh Good Health Study.

Because noninstitutionalized senior citizens comprise over 95% of the population 65 years of age and older, their health needs are a major concern. Data regarding infections in this population including the epidemiology, morbidity, and mortality are lacking. The authors recruited a study population of 417 free-living persons, all 65 years of age or older, from two neighborhoods in Pittsburgh, Pennsylvania. After the collection of self-reported baseline information from these persons, they were monitored for all clinical infections for 2 years, beginning July 1986 and through June 1988, using clinic visits, hospitalizations, or phone calls when needed. The baseline information showed the study population of 417 persons to be comparable with a neighborhood comparison group and with established populations for epidemiologic studies of the elderly in three other states. The 24 months of infection surveillance yielded 494 diagnosed infections in 224 or 54% of the subjects. Respiratory infections were most frequent with 259 or 52% of the total, followed by genitourinary infections with 24%, skin infections with 18%, gastrointestinal infections with 4%, and other types of infection with 2%. By comparing 22 self-reported baseline conditions with the occurrence of infection, 10 historic factors were univariately significant for infection. Of these 10 factors, only history of a lung problem (relative risk = 1.7, 95% confidence interval (CI) 1.1-2.9) and history of difficulty controlling urination (relative risk = 2.7, 95% CI 1.3-4.9) were statistically significant in multivariate analysis. To our knowledge, this study represents the first prospective data on infections in the noninstitutionalized elderly. The data demonstrate the wide variety of infections that occurred in this population and suggest that persons with a history of any one of several medical problems were possibly at greater risk for infection.