外側肘部腱症に対する血小板リッチプラズマ注射とステロイド注射の比較：より高いリソース利用と外科的エスカレーションとの関連

Epicondylitis (lateral and medial) is a common tendinopathy that impairs function and quality of life. Corticosteroid injections (CSI) provide rapid but often short-lived symptom relief, while platelet-rich plasma (PRP) is used as a biologic alternative aimed at tendon regeneration. Comparative effectiveness between PRP and CSI remains uncertain in real-world settings.

We conducted a retrospective cohort study using de-identified electronic health records from the TriNetX Network (2010-2025). Adults ≥18 years with coded epicondylitis and subsequent PRP or CSI were included. Cohorts were 1:1 propensity-score matched on demographics and comorbidities (age, sex, race, type 2 diabetes, obesity, hypothyroidism, nicotine dependence). Outcomes were assessed over a period of 1 year after the index event and included repeat or new medication, opioid exposure, long-term opioid initiation, visits to the emergency department (ED), functional diagnoses (stiffness, weakness, mobility), physical therapy (PT) utilization, and surgical escalation. Hazard ratios (HRs) and risk ratios were estimated.

After matching, 1,064 PRP patients were compared with 1,064 CSI patients. PRP was associated with higher hazards of repeat or new medication (HR 1.33; 95% CI 1.18-1.50; RR 1.21), opioid exposure (HR 1.48; 95% CI 1.20-1.83; RR 1.43), PT utilization (HR 1.52; 95% CI 1.27-1.81; RR 1.41), joint stiffness (HR 1.64; 95% CI 1.04-2.59; RR 1.63), dependence on mobility aids (HR 3.63; 95% CI 1.80-7.31; RR 3.60), and surgical escalation (HR 2.57; 95% CI 1.19-5.56; RR 2.30). No significant differences were observed for ED visits, long-term opioid initiation, abnormal gait, muscle weakness, or contracture.

In this large, multi-institutional real-world cohort, PRP was associated with higher short-term utilization and treatment failure risks compared with CSI. While randomized trials suggest mid-term benefits of PRP, our findings highlight an efficacy-effectiveness gap, likely reflecting heterogeneity in PRP protocols and patient selection. Clinicians should counsel patients about the potential for early symptom flare and higher downstream resource use when considering PRP.