High Fracture Rate of AVANTA Silicone Implant Following Arthroplasty of the Thumb MCP Joint of Rheumatoid Arthritis Patients with Boutonniere Deformities.

We retrospectively investigated the mid-term outcomes of arthroplasty using the AVANTA silicone implant for thumb metacarpophalangeal (MCP) joints with boutonniere deformity in patients with rheumatoid arthritis (RA). This study involved 36 thumbs of 33 RA patients with a mean follow-up period of 5.1 years (range, 2.0-13.3). Postoperatively, the mean extension was significantly increased and the mean flexion was significantly decreased (p<0.001, p<0.001, respectively), resulting in the mean arc of range of motion (ROM) shifting in the direction of extension after surgery. Implant fracture was observed in 10 thumbs (28%), and 4 of these (11%) underwent revision surgery. The survivorship with implant fracture and revision surgery as endpoints were 73.4% and 91.8% at 5 years, respectively. The preoperative arc of ROM and the postoperative flexion range of the implant-fracture group were significantly greater than those in the no-implant-fracture group (p=0.039, 0.034, respectively). These results suggest the importance of patient education and careful rehabilitation to prevent excessive flexion. Overall, the AVANTA silicone implant showed a relatively high rate of implant fracture at our institute.

Inhibitory Effect of a Tankyrase Inhibitor on Mechanical Stress-Induced Protease Expression in Human Articular Chondrocytes.

We investigated the effects of a Tankyrase (TNKS-1/2) inhibitor on mechanical stress-induced gene expression in human chondrocytes and examined TNKS-1/2 expression in human osteoarthritis (OA) cartilage. Cells were seeded onto stretch chambers and incubated with or without a TNKS-1/2 inhibitor (XAV939) for 12 h. Uni-axial cyclic tensile strain (CTS) (0.5 Hz, 8% elongation, 30 min) was applied and the gene expression of type II collagen a1 chain (COL2A1), aggrecan (ACAN), SRY-box9 (SOX9), TNKS-1/2, a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS-5), and matrix metalloproteinase-13 (MMP-13) were examined by real-time PCR. The expression of ADAMTS-5, MMP-13, nuclear translocation of nuclear factor-κB (NF-κB), and ß-catenin were examined by immunocytochemistry and Western blotting. The concentration of IL-1ß in the supernatant was examined by enzyme-linked immunosorbent assay (ELISA). TNKS-1/2 expression was assessed by immunohistochemistry in human OA cartilage obtained at the total knee arthroplasty. TNKS-1/2 expression was increased after CTS. The expression of anabolic factors were decreased by CTS, however, these declines were abrogated by XAV939. XAV939 suppressed the CTS-induced expression of catabolic factors, the release of IL-1ß, as well as the nuclear translocation of NF-κB and ß-catenin. TNKS-1/2 expression increased in mild and moderate OA cartilage. Our results demonstrated that XAV939 suppressed mechanical stress-induced expression of catabolic proteases by the inhibition of NF-κB and activation of ß-catenin, indicating that TNKS-1/2 expression might be associated with OA pathogenesis.

Influence of Janus kinase inhibitors on early postoperative complications in patients with rheumatoid arthritis undergoing orthopaedic surgeries.

OBJECTIVE: We retrospectively reviewed the records of rheumatoid arthritis (RA) patients who underwent orthopaedic surgery to examine the influence of the perioperative use of Janus kinase (JAK) inhibitors on early postoperative complications. PATIENTS AND METHODS: Thirty-two patients with RA under disease control with JAK inhibitors who underwent 49 orthopaedic procedures were included in the study. Patient records after surgery were investigated for surgical site infection (SSI), delayed wound healing (DWH), a flare-up of the disease, preoperative and postoperative absolute lymphocyte counts (ALCs), venous thromboembolism, and other postoperative complications. RESULTS: JAK inhibitors were continued during the perioperative period in 31 procedures. In the remaining 18 procedures, JAK inhibitors were discontinued perioperatively with a mean discontinuation period of 2.4 days. No instances of SSI were identified in any patient during at least 90 days' follow-up, while DWH was seen in one patient. Disease flare-up was noted in two patients after 3 and 9 days of discontinuation of JAK inhibitors, respectively. The ALCs significantly decreased on postoperative Day 1 (P < .0001), and there was a significant correlation between pre- and post-one-day ALCs (r = 0.75, P < .0001). CONCLUSION: JAK inhibitors seem to be safe during the perioperative period of orthopaedic surgery.

Ideal insertion point and projection of the infra-acetabular screw in acetabular fracture surgery.

BACKGROUND: In acetabular fracture surgery, an infra-acetabular screw (IAS) is inserted from the anterior to the posterior column through the infra-acetabular corridor to stabilize both columns. Although the IAS is useful for increasing fixation strength, proper placement requires proficiency and often results in extraosseous screw penetration. The complex anatomy of the infra-acetabular corridor and difficult intraoperative detection of the ideal insertion point and angle make proper placement of the IAS challenging. This study aimed to detect the ideal insertion point and angle of the IAS based on anatomical landmarks that can be directly identified intraoperatively. METHODS: We retrospectively reviewed the pelvic CT of 50 adults who underwent serial slice CT imaging. The pelvic inlet plane (PIP), which contains the anterior border of both the sacroiliac joint and posterior superior edge of the pubic symphysis, was used as the reference plane for the pelvic coordinate system to simulate the ideal insertion of IAS. The distance from the posterior superior edge of the pubic symphysis to the ideal insertion point of the IAS (IAS distance) and the angle and length of the IAS that could be inserted from the ideal insertion point were measured. RESULTS: The mean IAS distance was 61.0 ± 5.7 mm (57.6 ± 4.3 mm in men and 64.4 ± 4.9 mm in women). The mean angle between ideal IAS and yz-plane on the outlet view (α-angle) was 8.4 ± 6.6 ° (6.4 ± 5.6° in men and 10.5 ± 7.0° in women). The mean angle between ideal IAS and y-axis on the yz-plane (ß-angle) was 86.5 ± 10.6 ° (86.0 ± 10.3° in men and 87.0 ± 10.9° in women). The length of IAS was 97.1 ± 4.7 mm in men and 89.2 ± 3.6 mm in women. CONCLUSION: The IAS ideal insertion point detected as a distance from the pubic symphysis may aid in the proper insertion of the IAS during surgery. The insertion angle was parallel or tilted 10 ° laterally to the longitudinal axis in the pelvic outlet plane and almost perpendicular to the PIP in the sagittal plane when inserted from the ideal insertion point.