In vitro effects of alendronate on fibroblasts of the human rotator cuff tendon.

BACKGROUND: Bone mineral density of the humeral head is an independent determining factor for postoperative rotator cuff tendon healing. Bisphosphonates, which are commonly used to treat osteoporosis, have raised concerns regarding their relationships to osteonecrosis of the jaw and to atypical fracture of the femur. In view of the prevalence of rotator cuff tear in osteoporotic elderly people, it is important to determine whether bisphosphonates affect rotator cuff tendon healing. However, no studies have investigated bisphosphonates' cytotoxicity to human rotator cuff tendon fibroblasts (HRFs) or bisphosphonates' effects on rotator cuff tendon healing. The purpose of this study was to evaluate the cytotoxicity of alendronate (Ald), a bisphosphonate, and its effects on HRF wound healing. METHODS: HRFs were obtained from human supraspinatus tendons, using primary cell cultures. The experimental groups were control, 0.1 µM Ald, 1 µM Ald, 10 µM Ald, and 100 µM Ald. Alendronate exposure was for 48 h, except during a cell viability analysis with durations from 1 day to 6 days. The experimental groups were evaluated for cell viability, cell cycle and cell proliferation, type of cell death, caspase activity, and wound-healing ability. RESULTS: The following findings regarding the 100 µM Ald group contrasted with those for all the other experimental groups: a significantly lower rate of live cells (p < 0.01), a higher rate of subG1 population, a lower rate of Ki-67 positive cells, higher rates of apoptosis and necrosis, a higher number of cells with DNA fragmentation, higher caspase-3/7 activity (p < 0.001), and a higher number of caspase-3 positive staining cells. In scratch-wound healing analyses of all the experimental groups, all the wounds healed within 48 h, except in the 100 µM Ald group (p < 0.001). CONCLUSIONS: Low concentrations of alendronate appear to have little effect on HRF viability, proliferation, migration, and wound healing. However, high concentrations are significantly cytotoxic, impairing cellular proliferation, cellular migration, and wound healing in vitro.

Outcomes of Arthroscopic Rotator Cuff Repair in Patients Who Are 70 Years of Age or Older Versus Under 70 Years of Age: A Sex- and Tear Size-Matched Case-Control Study.

PURPOSE: To compare the structural and clinical outcomes after arthroscopic rotator cuff repair (ARCR) of a case group aged 70 and above with those of a control group younger than 70, with the 2 groups matched for sex and tear size. METHODS: The case group, comprising 53 patients 70 or older, and the control group, comprising 159 patients younger than 70, all received ARCR to 1 shoulder with symptomatic full-thickness rotator cuff tear. The case and the control subjects, who were matched for sex and tear size to minimize bias related to tendon healing, received ARCR during the same period. The mean age was 71.8 ± 2.6 years in the case group and 59.3 ± 7.1 years in the control group. The minimum follow-up period was 1 year in both groups. Cuff integrity was evaluated using ultrasonography. Structural and clinical outcomes of the 2 groups were compared. RESULTS: Regarding structural outcomes, the complete healing, partial-thickness retear, and full-thickness retear rates were 66% (35/53), 15% (8/53), and 19% (10/53) in the case group, and 68% (108/159), 19% (30/159), and 13% (21/159), respectively, in the control group. The 2 groups had no significantly different retear rates (P = .52). Regarding clinical outcomes, the mean improvements in range of motion, pain, muscle strength, and age- and sex-matched Constant scores were not significantly different between the 2 groups (P > .37). The preoperative tear size was significantly associated with retear in both studied groups (P = .02). CONCLUSIONS: The clinical and structural outcomes of ARCR in patients 70 or older with symptomatic full-thickness rotator cuff tear are comparable with those in patients younger than 70 with at least 1-year follow-up. Preoperative tear size, a biological factor, is a strong predictor for retear. LEVEL OF EVIDENCE: Level III, a retrospective comparative (case-control) study.

Are serum lipids involved in primary frozen shoulder? A case-control study.

BACKGROUND: Hyperlipidemia is a proposed, but unproven, risk factor for primary frozen shoulder. The purpose of this study was to evaluate the association between serum lipid profiles and primary frozen shoulder. METHODS: This was a case-control study. The case group comprised 300 patients diagnosed with frozen shoulder from October 2009 to April 2013. Patients with diabetes, thyroid disease, or previous shoulder surgery or trauma were excluded. The control group comprised 900 age and sex-matched persons with normal shoulder function who visited our health promotion center for general check-ups during the same period. We calculated the odds ratios and 95% confidence intervals to identify any association between serum lipid level and primary frozen shoulder, using conditional logistic regression analysis. We evaluated continuous data on the serum levels of total cholesterol, calculated low-density lipoprotein, measured low-density lipoprotein, high-density lipoprotein, triglyceride, and non-high-density lipoprotein cholesterol. We also evaluated categorical data on hyper-cholesterolemia, hyper-low-density lipoproteinemia (calculated and measured), hyper-high-density lipoproteinemia, hyper-triglyceridemia, and hyper-non-high-density lipoprotein cholesterolemia. RESULTS: Univariate analysis of the continuous data showed total cholesterol (odds ratio, 1.010 [95% confidence interval, 1.006 to 1.013]; p < 0.001), calculated low-density lipoprotein (odds ratio, 1.008 [95% confidence interval, 1.004 to 1.012]; p < 0.001), measured low-density lipoprotein (odds ratio, 1.007 [95% confidence interval, 1.003 to 1.011]; p = 0.001), high-density lipoprotein (odds ratio, 1.015 [95% confidence interval, 1.006 to 1.024]; p = 0.001), and non-high-density lipoprotein cholesterol (odds ratio, 1.007 [95% confidence interval, 1.004 to 1.011]; p < 0.001) to be significantly associated with primary frozen shoulder. Univariate analysis of categorical values showed hyper-cholesterolemia (odds ratio, 1.789 [95% confidence interval, 1.366 to 2.343]; p < 0.001), calculated hyper-low-density lipoproteinemia (odds ratio, 1.609 [95% confidence interval, 1.210 to 2.138]; p = 0.001), measured hyper-low-density lipoproteinemia (odds ratio, 1.643 [95% confidence interval, 1.190 to 2.269]; p = 0.003), hyper-high-density lipoproteinemia (odds ratio, 1.440 [95% confidence interval, 1.062 to 1.953]; p = 0.019), and hyper-non-high-density lipoprotein cholesterolemia (odds ratio, 1.645 [95% confidence interval, 1.259 to 2.151]; p < 0.001) to be significantly associated with primary frozen shoulder. CONCLUSIONS: We conclude that hypercholesterolemia and inflammatory lipoproteinemias, particularly hyper-low-density lipoproteinemia and hyper-non-high-density lipoprotein cholesterolemia, have a significant association with primary frozen shoulder. Further research is needed to evaluate whether a non-optimal serum lipid level is a cause, a related co-factor, or a result of primary frozen shoulder.

Cytotoxic effects of ropivacaine, bupivacaine, and lidocaine on rotator cuff tenofibroblasts.

BACKGROUND: Concern has recently arisen over the safety of local anesthetics used on human tissues. HYPOTHESIS: Aminoamide local anesthetics have cytotoxic effects on human rotator cuff tenofibroblasts. STUDY DESIGN: Controlled laboratory study. METHODS: Cultured human rotator cuff tenofibroblasts were divided into control, phosphate buffered saline (PBS), and local anesthetic study groups; the PBS study group was further subdivided by pH level (pH 7.4, 6.0, and 4.4). The 6 local anesthetic subgroups (0.2% and 0.75% ropivacaine, 0.25% and 0.5% bupivacaine, and 1% and 2% lidocaine) were also studied at 10% dilutions of their original concentrations. Exposure times were 5, 10, 20, 40, or 60 minutes for the higher concentrations and 2, 6, 12, 24, 48, or 72 hours for the lower concentrations. Cell viability was evaluated through live, apoptotic, and necrotic cell rates using the annexin V-propidium iodide double-staining method. Intracellular reactive oxygen species (ROS) and the activity of mitogen-activated protein kinases (MAPKs) and caspase-3/7 were investigated. RESULTS: The control and PBS groups showed no significant differences in cell viability (P > .999). In the local anesthetic study groups, cell viability decreased significantly with increases in anesthetic concentrations (P < .001) and exposure times (P < .001), with the exception of the lidocaine subgroups, where this effect was masked by the very high cytotoxicity of even low concentrations. Among the studied local anesthetic subgroups, 0.2% ropivacaine was the least toxic. The levels of intracellular ROS of each local anesthetic subgroup also increased significantly (P < .05). The studied local anesthetics showed increases in the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), and p38 as well as in levels of caspase-3/7 activity (P < .001). CONCLUSION: The cytotoxicity of the anesthetics studied to tenofibroblasts is dependent on exposure time and concentration. Of the evaluated anesthetics, ropivacaine is the least toxic in the clinically used concentration. The studied anesthetics induce tenofibroblast cell death, mediated by the increased production of ROS, by the increased activation of ERK1/2, JNK, and p38 and by the activation of caspase-3/7. CLINICAL RELEVANCE: This study identified the cytotoxic mechanisms of aminoamide local anesthetics acting on rotator cuff tenofibroblasts. The greatest margin of safety was found in lower anesthetic concentrations in general and more specifically in the use of ropivacaine.

Do antioxidants inhibit oxidative-stress-induced autophagy of tenofibroblasts?

Recent research on tendinopathy has focused on its relationship to programmed cell death. Increased autophagy has been observed in ruptured rotator cuff tendon tissues, suggesting a causal relationship. We investigated whether autophagy occurs in human rotator cuff tenofibroblast death induced by oxidative stress and whether antioxidants protect against autophagic cell death. We used H2 O2 (0.75 mM) as oxidative stressor, cyanidin (100 µg/ml) as antioxidant, zVAD (20 µM) as apoptosis inhibitor, and 3-MA (10 mM) as autophagy inhibitor. We evaluated cell viability and known autophagic markers: LC3-II expression, GFP-LC3 puncta formation, autolysosomes, and Atg5-12 and Beclin 1 expression. H2 O2 exposure increased the rates of cell death, LC3-II expression, GFP-LC3 puncta formation, and autolysosomes. After we induced apoptosis arrest using zVAD, H2 O2 exposure still induced cell death, LC3-II expression, and GFP-LC3 puncta formation. H2 O2 exposure also increased Atg5-12 and Beclin 1 expressions, indicating autophagic cell death. However, cyanidin treatment reduced H2 O2 -induced cell death, LC3-II expression, GFP-LC3 puncta formation, and autolysosomes. Cyanidin and 3-MA similarly reduced the cell-death rate, and Atg5-12 and Beclin 1 expression. This study demonstrated that H2 O2 , an oxidative stressor, induces autophagic cell death in rotator cuff tenofibroblasts, and that cyanidin, a natural antioxidant, inhibits autophagic cell death.

Prediction of the location of the anterior branch of the axillary nerve, using correlations with physical factors: a cadaveric study.

BACKGROUND: Although axillary nerve injury is a catastrophic surgical complication, there is little data for precise prediction of the location of that nerve's anterior branch. To address that, the authors searched for a useful correlation between the acromion-axillary nerve distance (AAND) and one or more physical factors. METHODS: The heights, humeral lengths, AAND, and axillary nerve indexes (ANI: ratio between AAND and humeral length) of 25 male and 20 female cadavers were determined. Any gender differences in the mean measurements were determined. The correlations of each AAND with height, humeral length, and ANI were determined. The authors determined that using the ANI and the humeral length allowed the shortest prediction of the AAND. RESULTS: The mean AAND, cadaver height, and humeral length were 6.5 ± 0.8, 164.9 ± 10.0, and 33.5 ± 2.7 cm, respectively. An independent t test revealed significant gender differences in the mean AAND (P = .003), height (P = .000), and humeral length (P = .000), but not in the mean ANI (P = .564). The Pearson coefficients for the associations of the AAND with height (r = .767), humeral length (r = .797) and ANI (r = .732) demonstrated strong correlations (P < .001), especially with humeral length. The use of the ANI with the humeral length yielded the shortest predictions of AAND, with a 97.8% probability of safety. CONCLUSION: There is a strong correlation between AAND and humeral length. In clinical practice, humeral length and ANI are useful for predicting the location of the anterior branch of the axillary nerve, when the arm is positioned at the side in neutral rotation.

Vascular injury associated with blunt trauma without dislocation of the knee.

Failure to recognize popliteal artery injury and restore vessel continuity of flow after blunt trauma is a major cause of lower extremity amputation and morbidity. A high index of suspicion and early recognition of the injury are paramount for limb salvage. We experienced a rare case of poplitial artery occlusion with the presence of arterial pulses due to collateral circulation after blunt trauma. Expeditious revascularization was achieved by using posterior approach, allowing two surgical teams to work simultaneously. This case illustrates that, even in the absence of knee dislocation, surgeons must always consider the possibility of a popliteal artery damage whenever a blunt trauma near the knee.