RESUMO
BACKGROUND: The aim of our study was to evaluate whether an association exists between body mass index (BMI) category and post-operative opioid requirements among primary total joint arthroplasty (TJA) patients. METHODS: We retrospectively reviewed all primary unilateral total hip and total knee arthroplasty (THA/TKA, respectively) cases performed over a two-year period. We evaluated whether a relationship exists between five BMI categories (≤24.9, 25-29.9, 30-34.9, 35-39.9, ≥40) and morphine milligram equivalent (MME) use for total in-hospital, daily in-hospital, and total during six weeks post-discharge. Secondary outcomes included relationship with length of stay, discharge location, opioid refill rate, and pre-operative opioid usage. RESULTS: For all patients undergoing primary TJA, increasing BMI resulted in an incremental increase in post-operative total in-hospital MME use for each successive BMI category when compared to those with BMI ≤24.9 (p < 0.05). This association held true for the THA subset. Within the cohort as a whole, higher categories of BMI were associated with increased length of stay (35-39.9, ≥40), higher odds of needing a refill (30-34.9, 35-39.9, ≥40), and higher odds of discharging to a rehab facility (25-29.9, ≥40) (p < 0.05). There was an increasing proportion of pre-operative opioid use as BMI category increased (p < 0.0001). DISCUSSION/CONCLUSION: BMI category is associated with increased in-hospital opioid requirements among primary TJA patients. Such findings are an important step to better understanding pain control expectations and can help facilitate development of opioid reduction strategies.
RESUMO
BACKGROUND: Intratendinous injections may have important effects on the properties of collagen microarchitecture, morphology, and subsequent mechanical properties of the injected tendon. The purpose of this study was to examine the effects of intratendinous PRP injections; the injectant retention within tendons, the distribution of intratendinous injectant, and whether intratendinous injection or needle fenestration alters tendon morphology or mechanics. DESIGN: Controlled Laboratory Study. INTERVENTIONS: In the first part of the study, 18 lamb extensor tendons were selected to receive methylene blue-containing PRP injection (PRP/MB), methylene blue only injection (MB), or needle fenestration. The volume of retained injectant was measured and injectant distribution and tendon morphology were examined microscopically. In the second portion of the study, 18 porcine flexor tendons were divided into control, needle fenestration, or saline injection groups. Young's Modulus was then determined for each tendon under 0-4% strain. MAIN OUTCOME MEASURES: 1) Injectant volume retained; 2) Injectant distribution; 3) Post-injection/fenestration alterations in morphology, biomechanics. RESULTS: Intratendinous injectant is retained within the tendon. The difference between PRP and PRP/MB groups was not significant (p = 0.78). Intratendinous spread of the injectant solution within the tendon occurs primarily in the proximodistal direction, with very little cross-sectional penetration. Intratendinous injections resulted in microscopic morphology disruption (e.g., separation and disorganization of both the collagen bundles and cellular distribution). There were significant differences in Young's Modulus between control (Ectrl = 2415.48) and injected tendons (Einj = 1753.45) at 4% strain (p = 0.01). There were no differences in Young's Modulus between fenestrated and control tendons. CONCLUSIONS: Intratendinous PRP injections are retained within the tendon, and primarily distributes longitudinally with minimal cross-sectional spread. Intratendinous injections may alter tendon morphology and mechanics.