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Background: Total knee arthroplasty (TKA) demonstrates excellent durability using jig-based manual techniques (manual TKA [mTKA]), but significant rates of dissatisfaction remain. Modifications of mTKA techniques and TKA implant designs to improve outcomes have had minimal success. Studies comparing relative outcomes of mTKA and robotic-assisted TKA (raTKA) are limited. Purpose: This study sought to compare outcomes of mTKA and raTKA in patients at a single institution. Methods: We retrospectively reviewed all primary TKAs performed by 1 surgeon from 2015 to 2017. In all, 139 consecutive mTKAs (2015–2016) and 148 consecutive raTKAs (2016–2017) were included. No cases were excluded. Patient demographics, complications, readmission rates, and clinical and patient-reported outcomes were compared at a minimum of 1-year follow-up. A post hoc student t test and Pearson χ2 test were used for continuous and categorical data. Results: We found that mTKA patients compared with raTKA patients required significantly longer length of stay (LOS) (1.73 vs 1.18 days, respectively), greater morphine milligram equivalents consumption (89.6 vs 65.2, respectively), and increased physical therapy (PT) visits (13.0 vs 11.0, respectively) with increased 30-day readmission rates (4.3 vs 0.7%, respectively) that approached significance. Knee Injury and Osteoarthritis Outcome Score for Joint Replacement and the University of California at Los Angeles activity score did not differ significantly comparing raTKA with mTKA patients at 1 year. There were no differences in complication rates. Conclusion: Significant early clinical benefits were noted with raTKA, including lower opioid requirements, shorter LOS, and fewer PT visits when compared with mTKA. A reduction in 30-day readmission rates was noted with raTKA that was not significant. Excellent clinical results with similar patient-reported outcomes were noted in both groups at 1-year follow-up. Further prospective investigations at longer follow-up intervals comparing these techniques are warranted.

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Background:After spinal surgery and other orthopaedic procedures, most patients receive opioids for pain, leading to potential complications such as pseudarthrosis and opioid abuse associated with long-term use. As an alternative, the endocannabinoid system has been shown to have antinociceptive activity, while contributing to bone homeostasis via the CB1 and CB2 cannabinoid receptors. This study evaluates the impact of the cannabinoid receptor agonist WIN55,212-2 (WIN55) on osteogenic differentiation in vitro as well as bone regeneration and spinal fusion in a preclinical rat model.Methods:Primary rat bone marrow stromal cells were cultured in standard or osteogenic media and exposed to vehicle alone or WIN55. Runx2 and Alkaline phosphatase (Alpl) were quantified via qPCR (quantitative real-time polymerase chain reaction), followed by assessment of ALP activity and matrix mineralization. For in vivo evaluation, 45 female Sprague Dawley rats (n = 15 per group) underwent L4-L5 posterolateral spinal fusion with bilateral placement of collagen scaffolds preloaded with low-dose rhBMP-2 (recombinant human bone morphogenetic protein-2; 0.5 μg/implant). Postoperatively, rats received the vehicle alone or 0.5 or 2.5 mg/kg WIN55 via daily intraperitoneal injections for 5 days. Bone regeneration and spinal fusion were assessed using radiography, manual palpation-based fusion scoring, microcomputed tomography imaging, and histology.Results:mRNA expression levels of Runx2 and Alp were similar among cells treated with vehicle alone and WIN55. Likewise, exposure to WIN55 did not inhibit ALP activity or bone matrix mineralization. In this animal model, no significant differences were found among groups with regard to mean fusion score, fusion rate, or new bone volume.Conclusions:WIN55 showed no adverse impact on osteogenic differentiation, bone regeneration, and spinal fusion. This supports that cannabinoid receptor agonists should be further investigated as a potential alternative approach for postoperative analgesia following spinal fusion and other orthopaedic procedures requiring bone-healing.Clinical Relevance:The identification of alternative treatments for postoperative pain following orthopaedic surgical procedures is crucial in combating the ongoing opioid abuse crisis. The endocannabinoid system may represent a viable alternative target for addressing orthopaedic postoperative pain.

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