Background: Atypical femur fractures (AFF) are rare complications of denosumab therapy and typically require cessation of treatment to avoid contralateral AFF, which however triggers a rapid reversal of antiresorptive effects and increased risk of rebound vertebral fractures. Therapeutic options to prevent rebound bone loss remain unclear.

Aim: To evaluate changes in BMD and fracture incidence following teriparatide initiation after denosumab discontinuation in patients with AFF.

Methods: Audit of patients prescribed teriparatide between 2021 and 2025 at Royal North Shore Hospital (Sydney, Australia). Twelve patients met the inclusion criteria of transitioning to teriparatide immediately following denosumab cessation due to an AFF. 

Results: Prior to denosumab initiation, eight patients had received other antiresorptive therapies for a mean duration of 9.33 years (SD 4.33). The mean duration of denosumab therapy was 5.83 years (SD 2.64). From the commencement of any initial treatment up to denosumab cessation, overall BMD had increased by a mean of 14.13%. Following the transition to teriparatide, over a mean follow-up period of 3.3 years (IQR 3–4), no patients developed new vertebral fractures or contralateral AFF. Mean lumbar spine BMD remained stable (0.940 g/cm² vs 0.937 g/cm², p = 0.82) while hip BMD parameters declined: mean femoral neck BMD decreased from 0.696 to 0.657 g/cm² (p < 0.05), and total hip BMD decreased from 0.810 to 0.796 g/cm² (p = 0.05).

Conclusion: Teriparatide therapy following denosumab cessation in patients with AFF prevented rebound vertebral fractures and maintained lumbar spine BMD, but did not prevent rebound bone loss at the hip.