Comparison of implant cost and surgical time in arthroscopic transosseous and transosseous equivalent rotator cuff repair.

BACKGROUND: We investigated the cost savings associated with arthroscopic transosseous (anchorless) double-row rotator cuff repair compared with double-row anchored (transosseous-equivalent [TOE]) repair. METHODS: All patients undergoing double-row arthroscopic rotator cuff repair from 2009 to 2012 by a single surgeon were eligible for inclusion. The study included 2 consecutive series of patients undergoing anchorless or TOE repair. Excluded from the study were revision repairs, subscapularis repairs, patients with poor tendon quality or excursion requiring medialized repair, and partial repairs. Rotator cuff implant costs (paid by the institution) and surgical times were compared between the 2 groups, controlling for rotator cuff tear size and additional procedures performed. RESULTS: The study included 344 patients, 178 with TOE repairs and 166 with anchorless repairs. Average implant cost for TOE repairs was $1014.10 ($813.00 for small, $946.67 for medium, $1104.56 for large, and $1507.29 for massive tears). This was significantly more expensive compared with anchorless repairs, which averaged $678.05 ($659.75 for small, $671.39 for medium, $695.55 for large, and $716.00 for massive tears). Average total operative time in TOE and anchorless groups was not significantly different (99 vs. 98 minutes). There was larger (although not statistically significant) case time variation in the TOE group. CONCLUSIONS: Compared with TOE repair, anchorless rotator cuff repair provides substantial implant-related cost savings, with no significant differences in surgical time for medium and large rotator cuff tears. Case time for TOE repair varied more with extremes in tear size.

Treatment of massive and recurrent rotator cuff tears augmented with a poly-l-lactide graft, a preliminary study.

BACKGROUND: The incidence of failed rotator cuff repairs remains high, especially in the setting of massive tears or revision repairs. The purpose of this study was to evaluate patient outcomes and repair integrity after augmentation with the repair patch, a poly-l-lactide synthetic polymer. METHODS: Sixteen consecutive patients with massive or recurrent rotator cuff tears underwent open repair with synthetic poly-l-lactide patch augmentation. Two patients required the patch to bridge defects, and 1 patient retore after a motor vehicle accident and had revision surgery at another institution. The 13 remaining patients were retrospectively evaluated from 1.2 to 1.7 years (average, 1.5 years) after surgery by PENN, American Shoulder and Elbow Surgeons, and Single Assessment Numeric Evaluation scores. Magnetic resonance imaging was used to examine the integrity of the repair at a minimum of 1 year of follow-up. RESULTS: The mean age was 57.3 years (42-68 years). Five patients (38%) had an intact rotator cuff at the time of follow-up. The remaining patients (62%) had full-thickness tears. PENN scores significantly improved from a preoperative score of 50.9 to 77.6 (P < .005). American Shoulder and Elbow Surgeons scores significantly improved from 32.8 to 74.2 (P = .0001). Single Assessment Numeric Evaluation scores at latest follow-up were 76.2. CONCLUSION: Poly-l-lactide repair patch augmentation of massive and recurrent large to massive rotator cuff tears demonstrates significant improvement in shoulder outcome measures for this difficult population, despite a retear rate of 62%. Further investigation with larger, prospective long-term studies is needed to determine whether this technique provides a true benefit compared with traditional, nonaugmented repair.

Heat generated with pegged or keeled glenoid components fixed with defined amounts of cement.

Glenoid component loosening is a common complication of total shoulder arthroplasty and has been associated with the progression of radiolucent lines at the glenoid bone-cement interface. Generation of heat during the exothermic reaction of cement curing may cause osteonecrosis of bone, potentially leading to the development of radiolucent lines. The purpose of this study was to measure the heat generated with various defined amounts of cement used for glenoid component fixation.Ten fresh-frozen cadaver scapulas were randomized to receive a keeled or pegged component with 1, 2, 3, 5, or 7 g of cement for fixation. An infrared camera was used to record the surface temperature generated during the cement curing process to an accuracy of ±2.0°C. Computed tomography was used to evaluate the cement mantle. The maximum temperatures generated did not exceed the critical value for osteonecrosis (56°C) in any of the specimens. The 4 specimens without a complete mantle were those fixed with a smaller quantity of cement (1, 2, or 3 g), and the largest cement mantle thicknesses were observed with the use of 7 g of cement.Up to 7 g of cement can be used without significant concern for thermal necrosis. Incomplete cement mantles were observed when ≤3 g of cement was used for fixation. Our results suggest that surgeons should use >3 g of cement to avoid incomplete cement mantles and that up to 7 g of cement can safely be used for glenoid fixation.

Multivariate analysis of low-dose radiation-associated changes in cytokine gene expression profiles using microarray technology.

OBJECTIVE: The availability of microarray technology, which permits evaluation of the entire cellular transcriptome in a single experiment, has provided new insights on the function of the genome under normal and pathological conditions, as well as in response to genotoxic stimuli, including ionizing radiation. The aims of this study were to: 1) determine whether specific cytokine gene expression profiles can be delineated in individuals exposed to chronic, low-dose radiation; and 2) compare analyses from three multivariate analytic methodologies, hierarchical clustering analysis (HCA), principal component analysis (PCA), and projection pursuit (PP), in evaluating transcriptional responses in human mononuclear cells to low doses of ionizing radiation (IR), as determined by cDNA microarrays. MATERIALS AND METHODS: Total RNA isolated from mononuclear cells of 19 apparently healthy adult individuals exposed to low doses of IR ranging from 0.18 mSv to 49 mSv over a period of 11 to 13 years, as a result of the Chernobyl Nuclear Power Plant catastrophe, was reverse transcribed in the presence of radioactive dATP to generate radiolabeled complementary cDNA. Target cDNA was hybridized to human cytokine and receptor arrays and mRNA transcriptional patterns were evaluated using HCA, PCA, and PP. RESULTS: Statistical analyses of the data generated from 19 microarrays revealed distinct gene expression patterns in mononuclear cells of individuals exposed to radiation doses of greater than 10 mSv or less than 10 mSv. Genes encompassed within clusters discerned by HCA, PCA, and PP varied depending on the methodology used to analyze the microarray data. The most frequently expressed genes across all radiation doses were serine/threonine protein kinase receptor (11/19), transforming growth factor (TGF) receptor (11/19), EB13 (10/19), and CD40 ligand. CONCLUSIONS: Although our findings suggest that it may be possible to assign gene expression profiles to low-dose-irradiated individuals, we show that gene expression profiles vary, depending on the statistical method used to analyze the data. Since there is, as of yet, no consensus regarding the best method to analyze a multivariate dataset, and since discarding the raw data and repeating the experiment at a later date constitutes an unwarranted expenditure, it is important to submit microarray data to public databases where these data can be reevaluated and interpreted by investigators holding expertise in various fields within the scientific community, including radiation biology, statistics, and bioinformatics.