Publications (3)8.96 Total impact
- [Show abstract] [Hide abstract] ABSTRACT: To evaluate the effects of high-pressure pulsatile lavage (HPPL) irrigation on new bone formation and fracture union in a contaminated intraarticular fracture, 45 New Zealand white rabbits were divided into three equal groups. The control group (C) underwent an osteotomy of the medial femoral condyle, contamination with a slurry of clay mixed with Staphylococcus aureus, stabilization and closure. The bulb syringe and pulsatile groups (B and P) underwent an identical procedure, with the addition of irrigation with 11 of saline by bulb syringe or pulsatile lavage system. Two fluorescent bone stains that mark new bone formation were administered subcutaneously: xylenol orange at the time of surgery and calcein green one week postoperatively. Animals were euthanized two weeks postoperatively and femurs were retrieved for histological analysis. Union was determined by examination of microradiographs. The viability of bone along the osteotomy site in the first and second weeks after irrigation was determined by evaluation of the two fluorescent stains. The density of new bone two weeks after irrigation was assessed by digitization of the microradiographs. Nonunion was present in 77%, 53%, and 43% of animals in groups C, B, and P, respectively. There was an increase in the presence of bands of both fluorescent stains along the osteotomy site in the groups B and P compared to group C. There was no statistically significant difference between groups B and P in either fluorescent stain. On digitization of microradiographs, there was more calcified new bone on postoperative day 14 in group P than in either group B or C (p = 0.04). The addition of contamination and foreign material to an intraarticular fracture model results in lower rates of new bone formation and fracture union. Irrigation in this setting is clearly beneficial, whether the irrigant is delivered by bulb irrigation or by HPPL. The results of this study indicate using HPPL in this setting does not cause greater damage than using bulb syringe irrigation.
- [Show abstract] [Hide abstract] ABSTRACT: The mechanism through which ligaments and tendons change length during growth and contracture is unclear. It has been hypothesized that there is a reversible "interfibrillar bond" that, when broken, allows the sliding of collagen fibrils past one another during length changes. The pentapeptide NKISK has been reported to inhibit the binding of decorin to fibronectin. This study was designed to evaluate the effect of NKISK in an in vivo model. Male Sprague-Dawley rats were divided into three groups (n = 9, 9 and 14, respectively). The left patellar tendon was injected with 1.0 ml of NKISK (Group 1 = 1.0 mM, Groups 2 and 3 = 5.0 mM). The contralateral/control limb was injected with carrier. Group 1 was sacrificed after three, Group 2 after four and Group 3 after seven daily injections. The patellar tendon lengths were measured in all groups with comparisons made to the contralateral control limb. NKISK injection resulted in a significant increase in length in Group 2 (3.14% +/- 2.04, P = 0.002) and in Group 3 (6.12% +/- 3.84, P < 0.001). Biomechanical testing of Group 3 showed no differences in maximum load, ultimate strength, structural stiffness, or elastic modulus of the treated tendons but did demonstrate a statistically significant decrease in the displacement and strain at maximum load in the NKISK-treated tendons. This study demonstrates that inhibition of decorin/fibronectin binding by NKISK results in tendon lengthening in an in vivo setting as noted by a progressive increase in the length of the patellar tendon.
- [Show abstract] [Hide abstract] ABSTRACT: The pentapeptide NKISK has been reported to inhibit the binding of decorin, a proteoglycan on the surface of collagen fibrils, to fibronectin, a tissue adhesion molecule. Because of our interest in fibril-fibril binding as it relates to changes in length of ligament or tendon (during growth or contracture), we investigated the potential of this peptide to dissociate fibrils. The peptide permitted the release of intact fibrils into suspension for examination under the electron microscope (which has not previously been possible in mature vertebrate tissues).
University of North Carolina at Chapel Hill
North Carolina, United States
- • Department of Medicine
- • Department of Orthopaedics