才津 旭弘

BACKGROUND: This study aimed to morphologically and histologically examine whether pig is useful as models for rotator cuff tear (RCT). METHODS: The morphology of the scapula and humerus bones was evaluated by taking X-ray and three-dimensional computed tomography (3D CT) scans of the right shoulders of five female pigs (age: 4 months). The rotator cuff (RC) footprint at the humeral insertion of these was observed and its shape was measured. Next, they underwent general anesthesia and an acute rotator cuff tear/rotator cuff repair (RCT/RCR) model was created using a deltoid split approach. Four weeks after surgery, the animals were euthanized, the shoulder joints were harvested, and the repaired RC was evaluated by hematoxylin and eosin staining and toluidine blue staining. RESULTS: The scapula of the pig had a vestigial acromion, in contrast to that in humans. The supraspinatus and infraspinatus tendons were connected so as to overlap each other and attached to the postero-superior part of the greater tuberosity. These tendons were located extra-articularly, separate from the joint capsule. The average antero-posterior length of the foot print was 17.4 ± 0.7 mm on the medial margin and 19.1 ± 2.2 mm on the lateral margin. The maximum medial-to-lateral width of it was 5.1 ± 0.5 mm. In all RCT/RCR models at 4 weeks after surgery, the repaired RC compound tendon was visually confirmed to be continuous with the footprint. Histologically, it was confirmed that regeneration of the four-layer structure of the bone-tendon junction had occurred. CONCLUSION: Porcine supraspinatus and infraspinatus attachment to the greater tuberosity have a structure similar to that of sheep and dogs, which is advantageous for creating the RCT/RCR model. It might be used for future in vivo studies of shoulder joint diseases. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: Pigs could potentially serve as a viable model for rotator cuff tears.

BACKGROUND: Malpositioning of the acetabular cup during total hip arthroplasty (THA) can lead to complications. Robotic surgery and navigation techniques aim to address this issue, but there is limited evidence regarding which method can achieve better clinical outcomes. Therefore, this network meta-analysis (NMA) aimed to compare the efficacy of various navigation methods. METHODS: This NMA of prospective randomized controlled trials compared robot-assisted systems (RAS), computer-assisted navigation systems (CAS), augmented reality-based portable navigation (AR), patient-specific instrumentation (PSI), portable accelerometer-based navigation (PN), and conventional methods (C) for THA procedures. We searched MEDLINE, EMBASE, Cochrane, Central Register of Controlled Trials, International Clinical Trials Platform Search Portal, and ClinicalTrials.gov. databases. The primary outcomes included revision surgery and postoperative clinical scores, and the secondary outcomes encompassed cup placement accuracy, acetabular cup placement outliers from the Lewinnek safe zone, surgical time, and complications. We used a Bayesian random-effects NMA, and confidence of evidence was assessed using confidence in NMA. RESULTS: We identified 45 studies including 2,122 patients. We did not find large differences in revision surgery, clinical outcome scores, cup inclination, or anteversion angle accuracy among the modalities. AR, CAS, and PSI exhibited a lower risk of outliers from safe zones than C. In addition, RAS and CAS had a longer surgical time than C. CONCLUSIONS: Robotic and navigation tools did not reduce the revision risk or enhance clinical outcomes. AR, CAS, PSI, and PN may decrease the risk of cup placement outliers in safe zones. However, the cup placement accuracy was equivalent, and the surgical time may be longer in RAS and CAS than in C. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

OBJECTIVE: Oxidative stress is considered to increase fracture risk, and lipid oxidation can adversely affect bone health. 4-hydroxynonenal (4-HNE) is a representative marker of lipid oxidation. METHODS: We investigated the association between 4-HNE and fracture risk in community-dwelling older subjects (n=78, mean age=78 years). Serum albumin, C-reactive protein, and 4-HNE values were examined with the Fracture Risk Assessment Tool (FRAX®). The FRAX® score of >15% was defined as a high fracture risk. RESULTS: There was a significantly higher 4-HNE value in the group of high fracture risk (n=38, median=12.4 ng/mL) than in the low-risk group (n=40, median=9.8 ng/mL; p=0.02). The correlation of FRAX® major osteoporosis (β=0.45) and FRAX® hip fracture (β=0.44) with 4-HNE was significant after adjustment for multiple variables. CONCLUSIONS: 4-HNE was suggested to be positively associated with fracture risk. This molecule may be a clinical candidate oxidative stress marker for fracture risk in the older population.

PURPOSE: To evaluate the effect of untreated medial meniscal ramp lesions (MMRLs) on the tendon graft after anterior cruciate ligament (ACL) reconstruction and histological findings of medial meniscus (MM) in a porcine a model. METHODS: A total of 17 pigs were divided into two groups: (1) the untreated MMRL group (UM group, n = 9) and (2) intact MM group (n = 8) and euthanized 12 weeks after surgery. The specimens were then tested cyclically and loaded to failure. Side-to-side differences (SSDs) in translation under cyclic loading and structural properties were analyzed. Histological evaluation of the MM was also performed. RESULTS: No significant differences in the SSD in translation during the cyclic testing (UM group, 0.3 ± 0.4 mm; intact MM group, 0.1 ± 1.4 mm), upper yield load (UM group, 476.3 ± 399.9 N; intact MM group, 643.2 ± 302.9 N), maximum load (UM group, 539.5 ± 265.8 N; intact MM group, 705.8 ± 282.6 N), linear stiffness (UM group, 63.5 ± 39.0 N/mm; intact MM group, 73.7 ± 60.1 N/mm) and elongation at failure (UM group, -4.6 ± 16.3 mm; intact MM group, 2.3 ± 6.6 mm) were observed. However, the UM group had significantly worse Modified Mankin's histological grading scores (1.8 ± 0.4 [1-2] vs. 0 ± 0 [0]; p < 0.001) and Modified Copenhaver classification scores (6.6 ± 2.4 [2-9] vs. 0.7 ± 1.1 [0-3]; p < 0.001) than did the intact MM group. CONCLUSION: Untreated MMRLs showed postoperative histological deterioration. LEVEL OF EVIDENCE: Level IV.