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Background: Surgeons use various irrigation solutions to minimize the risk of prosthetic joint infection after total joint arthroplasty. The toxicity of these solutions is an important consideration in their use. This study investigates the effect of irrigation solutions Bacitracin, Clorpactin (sodium oxychlorosene), and Irrisept (chlorhexidine) on osteoblast cytotoxicity and proliferation. Methods: Four replicates of 6 conditions at 3 time points (1, 2, and 4 min) were tested: control (normal saline), Bacitracin (33 IU/ml), Clorpactin (0.05%, 0.1%, 0.2%), and Irrisept (0.05% chlorhexidine gluconate). Human osteoblasts were cultured at 37 C and 5% CO 2 until confluent monolayers were obtained. The treatment solution was applied, and cells were washed 3x with warm phosphate-buffered saline and then supplemented with a fresh medium. Phase-contrast images were taken before and after treatment. The cytotoxicity and proliferation of the treated cells was measured for all conditions on day 3 and day 5 after treatment using the alamarBlue assay. Results: All test conditions showed morphological changes to cells after treatment; controls did not. Cells demonstrated curling and detachment. This effect was the worst and permanent with Irrisept, whereas other treatments showed a return to normal morphology after 1 week. All treatments showed increased %alamarBlue reduction after 5 days except Irrisept, which showed decreased reduction. There was no statistically significant time or dose dependence with Clorpactin treatment. Conclusions: Clorpactin and Bacitracin are damaging to human osteoblast cells in vitro as compared with normal saline. This damage is at least partially reversible as shown by morphology and cell viability assay. Irrisept caused more damage than either Clorpactin or Bacitracin, and the damage was not reversible.

Historically, cementless total knees were associated with early failure, which made cemented total knee arthroplasty the gold standard. Manufacturers have introduced newer uncemented technologies that provide good initial stability and use highly porous substrates for bony in-growth. The authors hypothesized that the implants would have equivalent 90-day clinical and economic outcomes. Prospectively collected data on 252 uncemented knees in the Michigan Arthroplasty Registry Collaborative Quality Initiative database were reviewed. Ninety-day outcomes, demographics, length of stay, complications, emergency department visits, readmissions, and financial data were compared with those of an age-matched group of cemented knees. Uncemented knees had shorter length of stay (1.58 vs 1.87 days; P <.01), were more frequently discharged home (90.48% vs 68.75%; P <.0001), and used less home care (6.35% vs 19.14%; P <.0001) or extended care facilities (2.78% vs 11.72%; P =.0001). More uncemented knees had “no complications.” Moreover, there were no re-operations in uncemented knees, compared with 19 reoperations in cemented knees. Uncemented knees were better than age-matched counterparts for Knee injury and Osteoarthritis Outcome Score (63.69 vs 47.10, n=85 and n=43, P <.0001) and Patient-Reported Outcomes Measurement Information System (PROMIS) T-Physical and T-Mental scores (44.12 vs 39.45, P <.0001; 51.84 vs 47.82, P =.0018). Cemented cases were more expensive overall, and surgical ($6806.43 vs $5710.78; P <.01) and total hospital ($8347.65 vs $7016.11; P <.01) costs were higher. The 90-day readmission and hospital outpatient costs were not significantly different between designs. Uncemented total knee arthroplasty, when using modern technologies, is successful and economically viable for an at-risk bundle. The results of this study should alleviate fears of increased cost, early failure, complications, or poor outcomes with the use of a modern uncemented total knee arthroplasty. [ Orthopedics . 2019; 42(6):355–360.]

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