Associations between fatty infiltration of rotator cuff muscles and tear size or location of rotator cuff tendon.

Background: Fatty infiltration (FI) of rotator cuff muscles in patients with rotator cuff tears is an important imaging factor for determining surgical indications. However, the associations between FI grade and the size or location of adjacent rotator cuff tears are not well-known. This study aimed to primarily determine whether tear size and location, especially for the SSc tendon, are associated with FI of adjacent rotator cuff muscles. The secondary aim was to clarify which patient factors are associated with rotator cuff muscle FI in rotator cuff tear cases. Methods: This study examined 373 shoulders of 348 patients (264 males and 109 females; mean age of 62.8 years) who underwent arthroscopic rotator cuff surgery. The FI grades of the supraspinatus (SSP), infraspinatus (ISP), and subscapularis (SSc) muscles were assessed using preoperative magnetic resonance imaging (MRI) using the Goutallier classification modified by Fuchs. According to the preoperative MRI and intraoperative findings, the tear size of the posterior-superior rotator cuff (SSP-ISP) was classified using a modified six-grade scale of the Cofield classification, and that of the SSc tear was classified using a six-grade scale according to the Lafosse classification. Age at surgery, sex, body mass index (BMI), presence of diabetes mellitus (DM) or hyperlipidemia (HL), trauma history, and duration of symptoms were investigated. Results: The FI grades of the SSP, ISP, and SSc were significantly associated with the size of the tears in those muscles (all P < 0.01). Furthermore, the FI grades of the SSP and the ISP were significantly associated with SSc tear size (P < 0.01), and the FI grade of the SSc was significantly associated with SSP-ISP tear size (P < 0.01). Patient age at surgery was significantly associated with FI grade (P < 0.01), with significant progression of the FI grade with advancing age. However, there were no significant associations between the FI grade and sex, BMI, presence of DM or HL, trauma history, and duration of symptoms. Conclusions: The FI grade of each of the rotator cuff muscles is affected by not only the tear severity of the muscle concerned but also by the severity of any tear in the adjacent rotator cuff.

Characteristics and Clinical Assessment of Elbow Pain in Youth Baseball Players.

Elbow injuries related to the throwing motion in baseball during the growth period present difficulties for early detection and may cause serious future disabilities. This study aimed to comprehensively determine the characteristics and clinical assessment of elbow pain in youth baseball players. Two hundred and sixteen young baseball players underwent elbow medical examination. Basic information and physical examination, clinical assessment, and ultrasonography results were examined. Univariate analyses were statistically performed between the pain-free (98 participants) and elbow pain (118 participants) groups. The mean age was 11.6 years, and ultrasonographic abnormalities were found on the medial side of the elbow in 37.5%. In total, 118 (54.6%) participants experienced elbow pain, with 64.4% of them complaining of elbow pain on the medial side. Players with multiple positions (≥2 positions) had a significantly higher prevalence of elbow pain. Height, weight, length of baseball experience, and positive rates of horizontal flexion and moving valgus stress tests were higher in the elbow pain group than in the pain-free group. The risk factors and clinical assessment for elbow pain are useful for the prevention and early detection of throwing elbow injuries in youth baseball players.

Epidemiological survey and risk factor analysis of dialysis-related amyloidosis including destructive spondyloarthropathy, dialysis amyloid arthropathy, and carpal tunnel syndrome.

The RDT population, initially at 215 patients, exceeded 300,000 in 2011, with a total of 329,609 patients at the end of December 2016. In our Institute, the number of patients with destructive spondylosis is increasing with the increase in the number of dialysis patients in Japan. We had 14 Cases in the 1990s, and then 82 cases in the 2000s and have already had 131 cases in the 2010s. The purpose of this study was to investigate the incidence of dialysis-related amyloidosis (DRA) such as destructive spondyloarthropathy (DSA), dialysis amyloid arthropathy (DAA), and carpal tunnel syndrome (CTS). In addition, another purpose was to examine the risk factors of the DRA. DAA made its own assessment on radiographs based on stage. Survey items were patient's basic data, laboratory data and X-ray view. Patient's basic data included such as sex, age, height, and weight and RDT-related factors such as kidney disease that led to RDT, age at start of RDT, RDT history, medical history (past and present), and history of surgery. The frequency of DRA was examined by medical history and radiological examination in 199 dialysis patients who obtained informed consent. The patients were divided into two groups according to the presence or absence of DRA, and risk factors of DRA were investigated from the medical history, basic data of patients, and blood tests. Of the 199 patients on regular dialysis therapy, 41 (20.6%) showed DRA. Based on the X-ray images, 21 patients (10.6%) showed DSA, while 22 patients (11.1%) showed DAA. Sixteen patients (8.0%) had CTS, determined through a history of surgery. Regarding overlap of conditions, 14 had both DSA and DAA, 3 had both DSA and CTS, and 2 had both DAA and CTS. There were statistically significant differences between the two groups in the cause of disease in Chronic glomerulonephritis and Diabetic Nephropathy, age at the start of RDT, period of RDT, body weight, blood platelet count, and blood Ca level. When multivariate analysis was performed on these items, statistical differences were recognized only during the dialysis period. In conclusion, long dialysis period was a risk factor for DRA.

Bone Mineral Density and Microstructure of the Elbow in Baseball Pitchers: An Analysis by Second-Generation HR-pQCT.

BACKGROUND: Baseball pitchers' elbows are exposed to repeated overloading during the throwing motion, which causes bone structural changes such as bone sclerosis and osteophyte formation. They have been observed by clinical CT and MRI, while the bone microstructural change has not yet been studied in vivo. The aims of this study were to establish a method of imaging the elbow joint using second-generation high-resolution peripheral quantitative CT and to investigate the bone microstructural change in baseball pitchers' dominant elbows. METHODS: The subjects were 17 baseball pitchers. The elbow was fixed using a custom-made cast and scanned by second-generation high-resolution peripheral quantitative CT. The scan conditions were as follows: voxel size 60.7 µm, integration time 43 ms, scan length 30.6 mm, and total scan time 8 min. Volumetric bone mineral density (vBMD) and trabecular bone microstructure were analyzed in the 6.5-mm3 cubic regions set in the capitellum and trochlea, and the dominant and nondominant elbows were compared. RESULTS: vBMD, bone volume fraction (BV/TV), and trabecular thickness (Tb.Th) at the capitellum were significantly higher in the dominant elbow than in the nondominant elbow. On the other hand, no parameters at the trochlea were significantly different. CONCLUSIONS: Higher vBMD accompanied by thicker trabecular bone was observed at the capitellum. These bone microstructural changes would reflect the valgus stress generated by the pitching motion in the elbow joint.

Double-bundle anterior cruciate ligament reconstruction improves tibial rotational instability: analysis of squatting motion using a 2D/3D registration technique.

BACKGROUND: The anterior cruciate ligament-deficient (ACLD) knee requires appropriate treatment for the patient to return to sports. The purpose of this study was to clarify the kinematics of the anterior cruciate ligament-deficient knee in squatting motion before and after double-bundle anterior cruciate ligament reconstruction (DB-ACLR) using a 2D/3D registration technique. METHODS: The subjects of this study were 10 men with confirmed unilateral ACL rupture who underwent DB-ACLR. Computed tomography (CT) of the knee joints was performed before DB-ACLR. Fluoroscopic imaging of the knee motion in squatting before and after DB-ACLR was also performed. The 2D/3D registration technique is a method of calculating positional relationships by projecting the 3D bone model created from the CT data onto the image extracted from the fluoroscopic images. The tibial anteroposterior (AP) and rotational positions were analyzed with reference to the femur. RESULTS: The tibial AP position of the ACLD knees was significantly anterior to the contralateral knees (p = 0.015). The tibial rotational position of the ACLD knees was significantly internally rotated compared to the contralateral knees (p < 0.001). Both tibial AP and rotational positions improved after DB-ACLR (p < 0.001), with no significant differences compared to the contralateral knees. CONCLUSION: DB-ACLR improved not only tibial AP instability but also tibial rotational instability at knee flexion with weight-bearing. DB-ACLR appears to be a useful technique for normalizing the knee joint kinematics of ACLD knees.

Osteochondritis Dissecans of the Humeral Capitellum in Young Athletes: Comparison Between Baseball Players and Gymnasts.

BACKGROUND: Osteochondritis dissecans (OCD) lesions are often observed in the humeral capitellum both in young baseball players and gymnasts. It is generally believed that capitellar OCD in baseball players can be seen on an anteroposterior (AP) radiograph with the elbow in 45° of flexion. However, the mechanism of injury seems to be different in baseball players and gymnasts. Repetitive valgus overload with the elbow in flexion is believed to be the cause of capitellar OCD lesions in baseball players, whereas weightbearing with the elbow in extension may be the cause of OCD in gymnasts. PURPOSE: To determine the difference in capitellar OCD location between baseball players and gymnasts and to propose the optimal AP radiographic angle of the elbow for visualization of early-stage OCD lesions in adolescent gymnasts. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Subjects consisted of 95 baseball players (95 elbows) and 21 gymnasts (24 elbows) with a mean age of 13.7 years (range, 11-18 years). To localize the lesion, inclination of the affected area in the humeral capitellum against the humeral axis was investigated using sagittal computed tomography images of the elbow. The inclination angle was defined as the angle between the long axis of the humerus and the line perpendicular to a line that connected the anterior and posterior margin of the lesion. The inclination angle in each group was compared and statistically analyzed. RESULTS: The mean inclination angle was 57.6° ± 10.7° in baseball players and 28.0° ± 10.7° in gymnasts. Capitellar OCD lesions were located more anterior in baseball players when compared with gymnasts (P < .01). CONCLUSION: Due to differences in applied stress, capitellar OCD lesions in baseball players were located more anteriorly compared with those seen in gymnasts. Therefore, although AP radiographs with the elbow in 45° of flexion are optimal for detecting OCD lesions in baseball players, radiographs with less elbow flexion or full extension are more useful in gymnasts, especially in early-stage OCD.

Biofilm-forming Staphylococcus epidermidis expressing vancomycin resistance early after adhesion to a metal surface.

We investigated biofilm formation and time of vancomycin (VCM) resistance expression after adhesion to a metal surface in Staphylococcus epidermidis. Biofilm-forming Staphylococcus epidermidis with a VCM MIC of 1 µg/mL was used. The bacteria were made to adhere to a stainless steel washer and treated with VCM at different times and concentrations. VCM was administered 0, 2, 4, and 8 hours after adhesion. The amount of biofilm formed was evaluated based on the biofilm coverage rates (BCRs) before and after VCM administration, bacterial viability in biofilm was visually observed using the fluorescence staining method, and the viable bacterial count in biofilm was measured. The VCM concentration required to decrease BCR significantly compared with that of VCM-untreated bacteria was 4 µg/mL, even in the 0 hr group. In the 4 and 8 hr groups, VCM could not inhibit biofilm growth even at 1,024 µg/mL. In the 8 hr group, viable bacteria remained in biofilm at a count of 10(4) CFU even at a high VCM concentration (1,024 µg/mL). It was suggested that biofilm-forming Staphylococcus epidermidis expresses resistance to VCM early after adhesion to a metal surface. Resistance increased over time after adhesion as the biofilm formed, and strong resistance was expressed 4-8 hours after adhesion.

Biofilm deficiency in polysaccharide intercellular adhesin-negative variants of Staphylococcus epidermidis selected by subminimal inhibitory concentrations of gentamicin.

Staphylococcus epidermidis is a cause of orthopedic device-related infection, and to treat such infection, biofilms should be controlled. Polysaccharide intercellular adhesin (PIA) is associated with the biofilm-forming ability of staphylococcal strains. PIA in biofilm-positive staphylococcal strains can be detected by the Congo red agar (CRA) method. In this study, we used the CRA method to examine the effects of subminimal inhibitory concentrations (sub-MICs) of 11 antibacterial agents on PIA production by S. epidermidis. We found that the PIA-negative variants were selected only by sub-MICs of gentamicin (GM). This PIA-negative phenotype was maintained over several generations in the absence of GM. Such selection occurred in six of eight clinical isolates, as well as in the biofilm-positive control strain. No such selection occurred with aminoglycoside antibiotics except for GM. Most of the PIA-negative variants that were selected by GM showed a markedly lower biofilm-forming ability on stainless steel washers than their untreated parent strains. In conclusion, variants with lower biofilm-forming ability may be selected by a sub-MIC of GM. Investigation of the reason why variants with reduced biofilm-forming ability can be selected in the presence of sub-MICs of GM may contribute to strategies against biofilm-related infections.

Quantitative analysis of Staphylococcus epidermidis biofilm on the surface of biomaterial.

BACKGROUND: Staphylococcus epidermidis biofilm is considered to be an important cause of device-related infection. Polysaccharide intercellular adhesin (PIA), encoded by the icaADBC locus, has been found to be a functional component of S. epidermidis biofilm, but the sequential change of the ica gene expression during biofilm development is still unclear. We have established a quantitative experiment of biofilm formation on nontranslucent biomaterial surfaces using the biofilm coverage rate (BCR). In this study, we quantified the time course of biofilm formation on a biomaterial (stainless steel) surface by means of BCR, viable cell count (VCC) with colony-forming units, and ATP-bioluminescence (ATP) as relative light units, and investigated the time-course relationship between biofilm development process and ica gene expression using reverse transcription-polymerase chain reaction (RT-PCR). METHODS: S. epidermidis RP62A was inoculated on stainless steel washers and incubated for 0-8, 24, and 48 h. Biofilms attached to the washers were quantified by means of BCR, VCC, and ATP. RT-PCR of the ica gene was performed using total RNA isolated from biofilms at each incubation period. Results of these methods were compared. RESULTS: The amount of biofilms measured by BCR increased over time and particularly grew at 5-6 h into the incubation period. On the other hand, the results of VCC and ATP increased gradually, and at 24 h or 48 h the measurement values were very much greater than previously. Up to 8 h, there were significant correlations between BCR and VCC or ATP. The growth of BCR until 6 h is supported by RT-PCR of the ica gene. CONCLUSIONS: Compared with each result, two-dimensional biofilm occupation on a biomaterial surface is proposed to be rapidly completed within 6-8 h after bacterial attachment. Our data indicate that bacterial biofilms first grow two dimensionally with a producing matrix, and subsequently grow vertically and become mature.

New quantitative image analysis of staphylococcal biofilms on the surfaces of nontranslucent metallic biomaterials.

BACKGROUND: Implant-related infection after orthopedic surgery is difficult to cure. One of the causes of infection is the bacterial biofilm that forms around biomaterials used during surgery. Therefore, it is necessary to investigate bacterial biofilms extensively to resolve the problems of these postoperative infections. However, no established culture method or quantification system exists for bacterial biofilms grown on the surface of the metallic biomaterials used in orthopedics, which are nonradiolucent. The purpose of this study was to develop a quantitative method to evaluate the difference in resistance of stainless steel versus titanium to staphylococcal biofilms and the efficacy of antibiotics against biofilms. METHODS: The bacterial strains used in this study were three Staphylococcus aureus stains: strain Seattle 1945 and two clinical strains cultured from postoperative infections. Staphylococcal biofilms were formed on stainless steel washers (SUS304) and titanium washers (pure titanium). They were stained with crystal violet and were examined with a digital microscope to calculate the bacterial coverage rate (BCR) by NIH imaging. RESULTS: The BCR of S. aureus biofilms formed on stainless steel and titanium washers increased over time. At 24, 48, and 72 h after cultivation, the amount of biofilm on the surface of the stainless steel washers was significantly greater or tended to be greater than that on the titanium. Cefazolin was applied to the obtained biofilms of two clinically isolated S. aureus strains. Cefazolin did not eradicate the biofilms but significantly reduced the biofilm of one strain. CONCLUSION: The newly developed quantitative method (static microtube culture and measurement system) was useful for assessing the amount of bacterial biofilms on the surface of nontranslucent biomaterial. We found that titanium may be more resistant to bacterial infection than stainless steel. To control implant-related severe infections, the biomaterials should be assessed from the viewpoint of their resistibility to bacterial adhesions and infections.