1093 Opioid Requirements and Predictive Factors for Total Hip and Knee Arthroplasties. a 7-Year Major Trauma Centre Study

Aim

Total knee and hip arthroplasties have prolonged and uncertain pain and rehabilitation timelines, which can be debilitating for patients. In our study, we compare opioid requirements and analyse predictive factors between the two procedures.

Method

All patients undergoing primary total hip (THA) and knee (TKA) arthroplasties from 2015-2022 at a Major Trauma Centre were reviewed. Opioid prescriptions in the first post-operative year were calculated every month up to 6 months and then from the 7th-12th month. Overall prescribed Morphine Milligram Equivalents (MME) “strength” and days with at least one opioid prescription (“coverage”) were calculated. Demographic and comorbidity factors were also included in the multivariate model analysis.

Results

2908 THAs and 2235 TKAs were included. Patients undergoing THAs were younger (68.5 vs 70.2 years-old, p<0.001) and more commonly female (61% vs 58%, p = 0.022) compared to TKA patients. TKAs (843 MME), compared to THAs (614 MME), had significantly higher postoperative opioid strength requirement (p<0.001) and coverage requirement (p<0.001).

On comorbidity analysis, TKAs had the stronger comorbidity predictive value, with strength in the post-operative year being positively associated with heart failure (p = 0.04), kidney disease (p<0.001), connective-tissue disorders (p = 0.009), respiratory disease (p<0.001) and diabetes (p = 0.014). THA strength was associated with rheumatological conditions and diabetes (p<0.01). Both had numerous strong associations for first month opioid coverage requirements.

Conclusions

Our study enables a high-resolution breakdown of the rehabilitation and pain journey of patients undergoing THA and TKA and provides insight to patients and clinicians about factors predisposing to higher pain relief requirements.