CLN5 and radiculitis: BMPs are potent osteoinductive growth factors clinically used to treat nonunion.8 While BMPs can induce new bone formation even without grafting, the quality of bone formed is lower than that achieved with autologous bone grafting.16 Furthermore, BMPs are associated with dose-dependent adverse events, including soft-tissue swelling, local inflammation, osteolysis, ectopic bone formation, retrograde ejaculation, and radiculitis.16 Prostaglandin E2 receptor 4 (EP4) agonists, which have potent osteogenic effects,17 have emerged as potential alternatives to BMPs.