Shoulder disorders occasionally cause intractable pain. Central sensitization (CS) may be involved in such pain. Identifying risk factors associated with CS is crucial for effective pain control. This study aimed to determine the effects of shoulder osteoarthritis and rotator cuff tears (RCT) on CS and associated factors. This study included patients evaluated for CS using the Central Sensitization Inventory (CSI) before surgery for shoulder osteoarthritis, RCT, or cuff tear arthropathy. Patients with a CSI score of 40 or higher were defined as having CS. The relationships between glenohumeral osteoarthritis (GHOA), RCT size, and CS were statistically analyzed. Multiple regression analysis was performed to examine the factors affecting CSI scores. Subjects included 167 patients: 131 patients had RCT without GHOA, 23 had GHOA with RCT, and 13 had GHOA without RCT. The GHOA group had a significantly higher CSI score (27.5 [10.8–40.5] vs. 18.0 [10.0–27.5]) and CS prevalence (27.8% vs. 8.4%) than the RCT without GHOA group. There was no significant correlation between RCT size and CSI scores. Multiple regression analysis showed that female sex, severe pain, and long pain duration were associated with higher CSI scores. Considering the risk factors for CS might be helpful in shoulder treatment.

There are numerous reports of bone adaptation observed on plain radiography studies after the use of cementless short stems in reverse shoulder arthroplasty. However, reports on changes in bone mineral density (BMD) around the stem using dual-energy X-ray absorptiometry (DEXA) are prominently absent. In the present study, we measured BMD around the stem using DEXA and investigated changes over time from postoperative year 1 to year 2. Additionally, the relationship between BMD changes, filling ratio, and stem alignment was examined. Forty-seven patients with short cementless stems who could be assessed via DEXA at 1-2 years postoperatively were included. After dividing the zones around the stem into 5, the BMD in each zone was measured, in addition to BMD changes and amount of change from postoperative year 1 to year 2. The relationship between filling ratio and stem alignment on postoperative plain radiography was assessed. A significant decrease in BMD in zone 3 was observed between postoperative year 1 and year 2 (P = .02). Regarding filling ratio and stem alignment, a negative correlation between valgus stem alignment and BMD change observed in zone 1 (r = −0.470, P < .01). In addition, stem valgus greater than 6° correlated with a significant decrease in BMD in zone 1. (P = .01). No significant differences were found in the other zones. Furthermore, there was no correlation between filling ratio and BMD change. In reverse shoulder arthroplasty cementless short stems, changes that that occurred between postoperative year 1 to year 2 demonstrated a decrease in BMD in zone 3. In addition, a decrease in BMD in zone 1 was observed with a stem alignment of valgus 6° or higher, suggesting that stem alignment within valgus 6° is required to prevent a decrease in BMD.

Accurate deltoid muscle assessment after reverse shoulder arthroplasty (RSA) is difficult using magnetic resonance imaging due to metal artifacts. We hypothesized that measuring the deltoid muscle area (DA) in the middle part of the deltoid’s total length postoperatively would reduce metal artifacts and allow for an accurate assessment. This study aimed to assess the reliability and reproducibility of magnetic resonance imaging and evaluate its impact on postoperative outcomes. The DA in the middle part of the muscle’s total length was measured twice by four examiners using pre and postoperative magnetic resonance imaging in 60 patients who underwent RSA (22 men, 38 women; mean age: 77.4 years). The DA at the greater tuberosity was measured preoperatively, and its correlation with the middle part of the deltoid’s total length was evaluated. The Constant-Murley Score was measured at 2 years postoperatively, and its correlation with the DA in the middle part of the deltoid’s total length pre- and postoperatively was assessed. Intraclass correlation coefficients for intraobserver measurements of preoperative and postoperative DA in the middle part of the deltoid’s total length were almost perfect, with mean values of 0.98 and 0.97, respectively. The intraclass correlation coefficients for interobserver reliability regarding the first and second DA measurements in the middle part of the deltoid’s total length were 0.95 and 0.95 (preoperatively) and 0.89 and 0.90 (postoperatively). The Constant-Murley Score was assessed at 2 years postoperatively in 51 patients. Muscle strength was weakly and moderately correlated with preoperative DA (r = 0.33, P = .02) and postoperative DA (r = 0.49, P < .01), respectively. DA measurement in the middle part of the deltoid’s total length after RSA was not affected by metal artifacts and had excellent reproducibility. This measurement method positively correlated with postoperative muscle strength, suggesting its usefulness for predicting postoperative muscle strength.

Background/Objective: Anti-tumor effects of plasma-activated medium (PAM) were demonstrated using various malignant tumors. However, the anti-tumor effect of PAM on synovial sarcoma remains unclear. Therefore, we aimed to investigate the anti-tumor effects of PAM on synovial sarcoma and its underlying mechanisms, focusing on the quantitative analyses of both intracellular reactive oxygen species (ROS) and cell apoptosis. Methods: The human synovial sarcoma cell line HS-SY-II was used to investigate the cell viability after PAM treatment. We investigated the anti-tumor effects and side effects of local PAM injection in a synovial sarcoma xenograft murine model. Moreover, we observed PAM-induced intracellular ROS accumulation and cell apoptosis and assessed the involvement of intracellular ROS in the anti-tumor effects of PAM using an intracellular ROS scavenger. Results: PAM significantly decreased the viability of synovial sarcoma cells compared with untreated Dulbecco’s modified Eagle medium. Local PAM injection into a synovial sarcoma xenograft murine model significantly suppressed tumor growth, including tumor volume (p < 0.001) and weight (p = 0.031), without side effects. Regarding anti-tumor mechanisms, PAM induced significant cell apoptosis and intracellular ROS accumulation (p < 0.001). The intracellular ROS scavenger significantly inhibited the anti-tumor effect of PAM (p < 0.001). Conclusions: We confirmed the anti-tumor effects of PAM on synovial sarcoma in vitro and in vivo, as well as the absence of side effects. The underlying mechanism was suggested to involve cell apoptosis induced by intracellular ROS accumulation. Considering the various clinical issues associated with the existing treatments of synovial sarcoma, PAM is a promising new option.