Atypical femoral fracture (AFF) is generally a rare complication of long-term use of bisphosphonate (BP); glucocorticoid (GC) use and Asian race are also risk factors. Femoral localized periosteal thickening (LPT, also termed \"beaking\") of the lateral cortex often precedes AFF. This cohort study investigated the incidence of LPT and AFF and their clinical courses over 10 yr in patients with autoimmune inflammatory rheumatic diseases (AIRDs) treated with BP and GC. The study population consisted of 121 patients with AIRDs taking BP and GC. LPT was screened by X-ray, and the LPT shape was evaluated. Prednisolone (PSL) dose was 10 (8-12) mg/d at enrollment and 9 (6-10) mg/d at the last observation. LPT was evident in 10 patients at enrollment and increased linearly to 31 patients (26%) at the last observation. AFF occurred in 9 femurs of 5 patients with LPT. All patients with AFF had bilateral LPT, and the prevalence of pointed type and LPT height were higher in the AFF-positive group than in the AFF-negative group. AFF occurred before BP discontinuation in 2 patients, 1 yr after BP discontinuation in 1, after BP discontinuation followed by 7 yr of alfacalcidol use in 1, and after switching from alfacalcidol to denosumab in 1. The prevalence rates of AFF and LPT associated with long-term BP use with concomitant use of GC (mostly PSL ≥ 6 mg/d) in Japanese patients with AIRD increased over time. The selection of long-term osteoporosis treatment for LPT-positive patients is difficult in some cases.

OBJECTIVE: The incidence of femoral localized periosteal thickening (LPT), which can precede atypical femoral fracture (AFF), is not low (1-10%) in Japanese patients with autoimmune inflammatory rheumatic diseases (AIRDs). We explored the associations between underlying AIRDs and the prevalence of LPT.
METHODS: We conducted post hoc analyses of two cohorts that included a total of 280 Japanese women, 105 of whom had AIRDs and had been taking bisphosphonate (BP) and prednisolone (PSL) and 175 of whom had rheumatoid arthritis (RA).
RESULTS: LPT was detected in a total of 18 patients (6.4%) and 3 (1.1%) developed AFFs. RA was negatively correlated with LPT. A disease other than RA requiring glucocorticoid treatment, BP use ≥5 years, PSL use ≥7 years, and a PSL dose ≥5.5 mg/day were positively correlated with LPT. After adjusting for age, diabetes mellitus, and BP duration or daily PSL dose, RA was no longer associated with LPT.
CONCLUSIONS: LPT in Japanese patients with AIRDs was associated with BP and glucocorticoid treatment rather than underlying AIRDs. When PSL dose ≥5.5 mg/day is required long-term [typically combined with long-term BP treatment (≥5 years)], clinicians need to pay particular attention in cases LPT and AFF as well as glucocorticoid-induced osteoporosis.

BACKGROUND: Femoral localized periosteal thickening (LPT, also termed \"beaking\") of the lateral cortex often precedes an atypical femoral fracture (AFF). Bisphosphonate (BP) use, glucocorticoid use, and Asian race are major risk factors for developing such fractures. The aim of this study was to determine whether the trabecular bone score (TBS) reflecting the lumbar trabecular microarchitecture was related to LPT in glucocorticoid-treated Japanese patients with autoimmune diseases.
METHODS: We retrospectively investigated 111 women with autoimmune diseases treated with prednisolone (PSL) who had undergone both femoral X-ray and dual-energy X-ray absorptiometry of the L1 - L4 lumbar vertebrae and for whom TBS could be evaluated for two or more of these.
RESULTS: Femoral LPT was evident in the X-rays of 18 of 111 patients (16.2%). Higher body mass index (BMI), longer duration of PSL use and longer duration of BP use were significant in patients with LPT compared to those without. The TBS was significantly lower in patients with LPT than in those without (1.314 ± 0.092 vs. 1.365 ± 0.100, p = 0.044); however, the lumbar bone mineral density did not differ significantly (0.892 ± 0.141 vs. 0.897 ± 0.154 g/cm2, p = 0.897). TBS was significantly associated with LPT (odds ratio, 0.004; 95% CI, 0 - 0.96; p = 0.048), but not in the multivariate analysis including BMI, duration of PSL use and duration of BP use.
CONCLUSIONS: The TBS was lower in glucocorticoid-treated Japanese women with autoimmune diseases with LPT than in those without LPT, and deteriorated trabecular microarchitecture influenced by longer use of BP and glucocorticoid might be associated with the development of LPT.

The incidence of localized periosteal thickening (LPT, also termed beaking) of the lateral cortex that often precedes an atypical femoral fracture (AFF) was not high in patients with rheumatoid arthritis (RA) but incomplete AFFs developed in two patients. Higher-dose prednisolone was a significant risk factor for LPT in patients with RA.
BACKGROUND: Atypical femoral fractures (AFFs) are stress fractures; bisphosphonate (BP) use is a major risk factor for the development of such fractures. Localized periosteal thickening (LPT, also termed beaking) of the lateral cortex often precedes a complete or incomplete AFF. We evaluated the incidence of latent LPT in patients with rheumatoid arthritis (RA), to evaluate LPT progression, and to define LPT risk factors.
METHODS: A total of 254 patients with RA were included; all underwent annual X-ray evaluation, dual-energy X-ray absorptiometry, and analyses of serum and bone metabolic markers for 2-3 years. LPT of the lateral cortex was sought in femoral X-rays.
RESULTS: The incidence of LPT was 2.4% (6/254). Among patients on both BP and prednisolone (PSL) at enrollment, the incidence was 2.3% (3/131). Two femurs of two patients with LPT developed incomplete AFFs; LPT was extensive and associated with endosteal thickening. One patient had been on BP and PSL and microscopic polyangiitis was comorbidity. The other was on a selective estrogen receptor modulator and PSL. A daily PSL dose >5 mg (OR 11.4; 95%CI 2.15-60.2; p = 0.004) and higher-dose methotrexate (OR 1.22; 95%CI 1.01-1.49; p = 0.043) were significant risk factors for LPT.
CONCLUSIONS: The incidence of latent LPT was not high (2.4%) but incomplete AFFs developed in two RA patients. Higher-dose PSL because of a comorbid disease requiring glucocorticoid treatment other than RA or refractory RA were risk factors for LPT; X-ray screening for latent LPT would usefully prevent complete AFFs.