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Background: Infections following shoulder surgery, particularly periprosthetic joint infection (PJI), are challenging to treat. Cutibacterium acnes is the causative pathogen in 39% to 76% of these cases. This study explores the efficacy of bacteriophage therapy as an alternative to conventional antibiotics for treating such infections. Methods: Nine phages with lytic activity were isolated from the skin of humans using C. acnes ATCC 6919 as the indicator host. These phages were tested individually or in combination to assess host range and antibiofilm activity against clinical strains of C. acnes associated with PJIs. The phage cocktail was optimized for broad-spectrum activity and tested in vitro against biofilms formed on titanium discs to mimic the prosthetic environment. Results: The isolated phages displayed lytic activity against a range of C. acnes clinical isolates. The phage cocktail significantly reduced the bacterial load of C. acnes strains 183, 184, and GG2A, as compared with untreated controls (p < 0.05). Individual phages, particularly CaJIE7 and CaJIE3, also demonstrated significant reductions in bacterial load with respect to specific strains. Moreover, phages notably disrupted the biofilm structure and reduced biofilm biomass, confirming the potential of phage therapy in targeting biofilm-associated infections. Conclusions: Our preclinical findings support the potential of phage therapy as a viable adjunct to traditional antibiotics for treating C. acnes infections in orthopedic device-related infections. The ability of phages to disrupt biofilms may be particularly beneficial for managing infections associated with prosthetic implants. [ABSTRACT FROM AUTHOR]

Background: In addition to the integrity of the meniscal hoop function, both the anterior and posterior meniscus roots as well as the meniscotibial and meniscofemoral ligaments are crucial in restraining meniscal extrusion. However, the interaction and load sharing between the roots and these peripheral attachments (PAs) are not known. Purposes: To investigate the influence of an insufficiency of the PAs on the forces acting on a posterior medial meniscus root repair (PMMRR) in both neutral and varus alignment and to explore whether meniscal centralization reduces these forces. Study Design: Controlled laboratory study. Methods: In 8 fresh-frozen human cadaveric knees, an arthroscopic transosseous root repair (step 1) was performed after sectioning the posterior root of the medial meniscus. The pull-out suture was connected to a load cell to allow measurement of the forces acting on the root repair. A medial closing-wedge distal femoral osteotomy was performed to change the mechanical axis from neutral to 5° of varus alignment. The meniscus was completely released from its PAs (step 2), followed by transosseous arthroscopic centralization (step 3). Each step was tested in both neutral and varus alignment. The specimens were subjected to nondestructive dynamic varus loading under axial compression of 300 N in 0°, 15°, 30°, 45°, and 60° flexion. The changes in force acting on the PMMRR were statistically analyzed using a mixed linear model. Results: Axial loading in neutral alignment led to an increase of the force of root repair of 3.1 ± 3.1 N (in 0° flexion) to 6.3 ± 4.4 N (in 60° flexion). In varus alignment, forces increased significantly from 30° (3.5 N; 95% CI, 1.1-5.8 N; P =.01) to 60° (7.1 N; 95% CI, 2.7-11.5 N; P =.007) flexion, in comparison with neutral alignment. Cutting of the PAs in neutral alignment led to a significant increase of root repair forces in all flexion angles, from 7.0 N (95% CI, 1.0-13.0 N; P =.02) to 9.1 N (95% CI, 4.1-14.1 N; P =.003), in comparison with the intact state. Varus alignment significantly increased the forces in the cut states from 4.8 N (95% CI, 1.0-8.5 N; P =.02) to 11.1 N (95% CI, 4.2-18.0 N; P =.006) from 30° to 60° flexion, in comparison with the neutral alignment. Arthroscopic centralization led to restoration of the native forces in both neutral and varus alignment, with no significant differences between the centralized and intact states. Conclusion: An insufficiency of the PAs of the medial meniscus, as well as varus alignment, led to increased forces acting on a PMMRR. These forces were reduced via an arthroscopic meniscal centralization. Clinical Relevance: Performing arthroscopic meniscal centralization concomitantly with PMMRR may reduce failure of the repair by reducing the load of the root. [ABSTRACT FROM AUTHOR]

Glucocorticoids may be given prior to major orthopedic surgery to decrease postoperative nausea, vomiting, and pain. Additionally, many orthopedic patients may be on chronic glucocorticoid therapy. The aim of our study was to investigate whether glucocorticoid administration influences Orthopedic-Device-Related Infection (ODRI) in a rat model. Screws colonized with Staphylococcus epidermidis were implanted in the tibia of skeletally mature female Wistar rats. The treated groups received either a single shot of dexamethasone in a short-term risk study, or a daily dose of dexamethasone in a longer-term interference study. In both phases, bone changes in the vicinity of the implant were monitored with microCT. There were no statistically significant differences in bacteriological outcome with or without dexamethasone. In the interference study, new bone formation was statistically higher in the dexamethasone-treated group (p = 0.0005) as revealed by CT and histopathological analysis, although with relatively low direct osseointegration of the implant. In conclusion, dexamethasone does not increase the risk of developing periprosthetic osteolysis or infection in a pre-clinical model of ODRI. Long-term administration of dexamethasone seemed to offer a benefit in terms of new bone formation around the implant, but with low osseointegration. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the forces on a medial collateral ligament (MCL) reconstruction (MCLR) relative to the valgus alignment of the knee. Methods: Eight fresh‐frozen human cadaveric knees were subjected to dynamic valgus loading at 400 N using a custom‐made kinematics rig. After resection of the superficial medial collateral ligament, a single‐bundle MCLR with a hamstring tendon autograft was performed. A medial opening wedge distal femoral osteotomy was performed and fixed with an external fixator to gradually adjust the alignment in 5° increments from 0° to 10° valgus. For each degree of valgus deformity, the resulting forces acting on the MCLR were measured through a force sensor and captured in 15° increments from 0° to 60° of knee flexion. Results: Irrespective of the degree of knee flexion, increasing valgus malalignment resulted in significantly increased forces acting on the MCLR compared to neutral alignment (p < 0.05). Dynamic loading at 5° valgus resulted in increased forces on the MCLR at all flexion angles ranging between 16.2 N and 18.5 N (p < 0.05 from 0° to 30°; p < 0.01 from 45° to 60°). A 10° valgus malalignment further increased the forces on the MCLR at all flexion angles ranging between 29.4 N and 40.0 N (p < 0.01 from 0° to 45°, p < 0.05 at 60°). Conclusion: Valgus malalignment of the knee caused increased forces acting on the reconstructed MCL. In cases of chronic medial instabilities accompanied by a valgus deformity ≥ 5°, a realigning osteotomy should be considered concomitantly to the MCLR to protect the graft and potentially reduce graft failures. Level of Evidence: Level III. [ABSTRACT FROM AUTHOR]