Biomechanical Performance of Medial Row Suture Placement Relative to the Musculotendinous Junction in Transosseous Equivalent Suture Bridge Double-Row Rotator Cuff Repair.

PURPOSE: To compare the biomechanical performance of medial row suture placement relative to the musculotendinous junction (MTJ) in a cadaveric transosseous equivalent suture bridge (TOE-SB) double-row (DR) rotator cuff repair (RCR) model. METHODS: A TOE-SB DR technique was used to reattach experimentally created supraspinatus tendon tears in 9 pairs of human cadaveric shoulders. The medial row sutures were passed either near the MTJ (MTJ group) or 10 mm lateral to the MTJ (rotator cuff tendon [RCT] group). After the supraspinatus repair, the specimens underwent cyclic loading and load to failure tests. The localized displacement of the markers affixed to the tendon surface was measured with an optical tracking system. RESULTS: The MTJ group showed a significantly higher (P = .03) medial row failure (5/9; 3 during cyclic testing and 2 during load to failure testing) compared with the RCT group (0/9). The mean number of cycles completed during cyclic testing was lower in the MTJ group (77) compared with the RCT group (100; P = .07) because 3 specimens failed in the MTJ group during cyclic loading. There were no significant differences between the 2 study groups with respect to biomechanical properties during the load to failure testing. CONCLUSIONS: In a cadaveric TOE-SB DR RCR model, medial row sutures through the MTJ results in a significantly higher rate of medial row failure. CLINICAL RELEVANCE: In rotator cuff tears with tendon tissue loss, passage of medial row sutures through the MTJ should be avoided in a TOE-SB RCR technique because of the risk of medial row failure.

Suture Technique Influences the Biomechanical Integrity of Pectoralis Major Repairs.

Pectoralis major ruptures occur in large, muscular individuals, and repair constructs may experience significant tension. Four different suture techniques were evaluated biomechanically to determine the effect of suture technique on optimizing fixation strength. Forty fresh-frozen cadaveric shoulders were repaired using endosteal buttons. The control group was repaired with #2 polyblend suture in a modified Mason-Allen stitch configuration. The triple group was repaired using the same suture and configuration, but with the addition of triple-loaded buttons. The configuration group was repaired using the same suture in a Krackow/Bunnell configuration. The tape group was repaired using 2-mm polyethylene tape and #5 polyblend suture in the Krackow/Bunnell configuration. Under cyclic loading, there was no significant difference between groups. Under load-to-failure testing, the tape group withstood a significantly greater maximum load (726.0±90.0 N) than the control and triple groups (330.2±20.2 and 400.2±35.2 N, respectively; P<.005), and similar load to the configuration group (509.9±68.6 N; P=.16). The configuration group failed via suture breakage (9/10); the other groups failed via suture pullout, in which suture pulled through tendon (26/30). Pectoralis major repair in a running, locked configuration appears to improve biomechanical performance by preventing suture pullout. Use of a polyethylene tape construct demonstrates the potential for improved failure loads, but its role remains undefined.

Your garden hose: a potential health risk due to Legionella spp. growth facilitated by free-living amoebae.

Common garden hoses may generate aerosols of inhalable size (≤10 µm) during use. If humans inhale aerosols containing Legionella bacteria, Legionnaires' disease or Pontiac fever may result. Clinical cases of these illnesses have been linked to garden hose use. The hose environment is ideal for the growth and interaction of Legionella and free-living amoebae (FLA) due to biofilm formation, elevated temperatures, and stagnation of water. However, the microbial densities and hose conditions necessary to quantify the human health risks have not been reported. Here we present data on FLA and Legionella spp. detected in water and biofilm from two types of garden hoses over 18 months. By culturing and qPCR, two genera of FLA were introduced via the drinking water supply and reached mean densities of 2.5 log10 amoebae·mL(-1) in garden hose water. Legionella spp. densities (likely including pathogenic L. pneumophila) were significantly higher in one type of hose (3.8 log10 cells·mL(-1), p < 0.0001). A positive correlation existed between Vermamoebae vermiformis densities and Legionella spp. densities (r = 0.83, p < 0.028). The densities of Legionella spp. identified in the hoses were similar to those reported during legionellosis outbreaks in other situations. Therefore, we conclude that there is a health risk to susceptible users from the inhalation of garden hose aerosols.

Do free-living amoebae in treated drinking water systems present an emerging health risk?

There is an expanding body of evidence that free-living amoebae (FLA) increase both the numbers and virulence of water-based, human-pathogenic, amoeba-resisting microorganisms (ARM). Legionella spp., Mycobacterium spp., and other opportunistic human pathogens are known to be both ARM and also the etiologic agents of potentially fatal human lung infections. However, comparatively little is known about the FLA that may facilitate ARM growth in drinking water. This review examines the available literature on FLA in treated drinking water systems; in total 26 studies from 18 different countries. FLA were reported to breakthrough the water treatment barrier and enter distribution systems, in addition to the expected post-treatment system ingress. Once in the distribution system there is evidence of FLA colonization and regrowth especially in reservoirs and in-premise plumbing storage tanks. At the point of use the average FLA detection rate was 45% but highly variable (n = 16, σ = 31) due to both differences in both assay methods and the type of water systems examined. This review reveals that FLA are consistently detected in treated drinking water systems around the world and present a yet unquantified emerging health risk. However, more research is urgently required before accurate risks assessments can be undertaken to assess the impacts on human health, in households and institutions, due to exposure to FLA facilitated pathogenic ARM.