Osteoporosis and cement usage in total hip arthroplasty.

PURPOSE: Cement usage in total hip arthroplasty (THA) is increasingly common. However, osteoporosis-related fracture risk in cemented vs uncemented THA patients is poorly characterized. We aim to analyze the usage of metabolic bone care and osteoporosis fracture risk in cemented vs uncemented THA patients using FRAX and radiographic bone measurements. METHODS: Chart review on 250 THA patients was performed retrospectively. Demographics, FRAX scores, hip radiograph measurements, osteoporosis diagnosis, treatment and screening were compared between cemented and uncemented THA patients. Logistic regression model was used to analyze factors influencing cement usage. RESULTS: Cemented THA patients have significantly higher osteoporosis-related fracture risk as measured by FRAX major (20% vs 13%) and FRAX hip (8% vs 5%). There is no significant difference in osteoporosis treatment, vitamin D / calcium supplementation, or metabolic bone disease screening based on patients' cement status. Female sex and rheumatoid arthritis status significantly predict cement usage, but FRAX scores do not predict cement usage. Additionally, 50% (10/20) of patients with Dorr C classification were uncemented. CONCLUSION: Although some patients undergoing THA with high osteoporosis-related fracture risk were identified and cemented, some risk factors including poor proximal femur shape (by Dorr classification) and poor bone quality (as measured by FRAX score) were potentially overlooked. Cemented patients had an increased risk for fractures but did not receive appropriately increased osteoporosis screening or treatment. LEVEL OF EVIDENCE: III.

Bone loss after denosumab discontinuation is prevented by alendronate and zoledronic acid but not risedronate: a retrospective study.

A retrospective study of 121 patients who stopped denosumab (Dmab) then received no treatment (NT), risedronate (RIS), alendronate (ALN), or zoledronic acid (ZOL). Bone density (spine and hip) during and after Dmab discontinuation was measured. Treatment with ALN or ZOL, not NT and RIS, mitigated BMD loss after Dmab discontinuation. INTRODUCTION: Denosumab (Dmab) discontinuation is associated with bone loss and multiple vertebral fractures. The purpose was to compare bone mineral density (BMD) change in patients following Dmab discontinuation with no subsequent treatment (NT) and three bisphosphonate (BP) treatments: risedronate (RIS), alendronate (ALN), and zoledronic acid (ZOL). METHODS: In a review of 121 patients aged 71.2 ± 8.1 years, discontinuing Dmab (mean 5.4 doses), 33 received NT and 88 received BP (22 RIS; 34 ALN; 32 ZOL). BMD change after 1 year was compared between groups at the lumbar spine (LS), femoral neck (FN), and total hip (TH). Risk factors for bone loss after Dmab discontinuation were compared between groups and incidence of vertebral fractures was determined. RESULTS: Following Dmab discontinuation, LS mean change (g/cm2; 95% CI) was for NT: - 0.041 (- 0.062 to - 0.021); RIS: - 0.035 (- 0.052 to - 0.017); ALN: - 0.005 (- 0.020 to 0.009); and ZOL: - 0.009 (- 0.025 to 0.008). Differences in LS were found between NT and ALN (p =  0.015), and NT and ZOL (p=0.037), but not between NT and RIS. The only significant difference in TH was found between NT and ZOL (p 0.034) with no group differences in FN. BMD gains during Dmab treatment were associated with BMD loss after Dmab discontinuation. In a subset, discontinuation after Dmab treatment (> 5 doses) followed by ALN (n = 22) and ZOL (n = 11) showed no difference in BMD. Five of 7 vertebral fractures occurred after Dmab discontinuation in NT. CONCLUSION: Subsequent treatment with ALN or ZOL but not NT and RIS mitigates BMD loss after Dmab discontinuation.

Fracture Risk Assessment Tool Scores and Radiographical Bone Measurements in Total Hip Arthroplasty Patients.

BACKGROUND: Osteoporosis is a major risk factor for periprosthetic fractures (PPFx) in total hip arthroplasty (THA) patients but is not routinely screened for in this population. Given the availability of hip x-rays and preoperative screenings, Fracture Risk Assessment Tool (FRAX) scores and radiographic bone measurements are potentially promising, novel risk stratification tools. This study aims to characterize FRAX scores and radiographic bone measurements in THA and PPFx patients. METHODS: A retrospective chart review for demographic variables and FRAX scores was performed on 250 THA and 40 PPFx patients. Radiographic bone measurements including cortical thicknesses (both antero-posterior [AP] and lateral), canal to calcar ratio, canal flare index, and Dorr classifications were obtained from preoperative x-rays. Correlation between FRAX scores and radiographic bone measurements was investigated with linear regressions. FRAX scores and radiographic bone measurements were compared between the THA and PPFx patients. Multivariate logistic regressions were used to identify factors predicting PPFx. RESULTS: FRAX scores were significantly correlated with both AP (P < .001) and lateral (P = .007) cortical thicknesses. Compared to THA patients, those with PPFx had significantly higher FRAX scores (P = .003) and lower AP cortical thickness (P = .005). Multivariate logistic regressions demonstrated that FRAX major osteoporotic fracture risk score and AP cortical thickness were independent predictors of PPFx (P = .001 and .024, respectively). CONCLUSION: Cortical thicknesses are good proxy measurements of osteoporosis-related fracture risk in THA patients. In addition, both major and AP cortical thickness indices are promising tools for identifying patients who are at a high risk of PPFx in the THA population.

Total Joint Arthroplasty and Osteoporosis: Looking Beyond the Joint to Bone Health.

BACKGROUND: Metabolic bone diseases in the total joint arthroplasty (TJA) population are undertested and undertreated, leading to increased risk of adverse outcomes such as periprosthetic fractures. This study aims to better characterize the current state of bone care in TJA patients using Fracture Risk Assessment Tool (FRAX) score risk stratifications. METHODS: In total, 505 consecutive TJA patients who meet the Endocrine Society guidelines for osteoporosis screening were included for review. They were divided into a high risk or low risk group depending on FRAX scores and were compared based on screening, diagnosis, and treatment of metabolic bone disease. Logistic regression models were used to analyze factors influencing screening and treatment. A population analysis involving 2,000 TJA patients, and a complication analysis involving 40 periprosthetic fracture patients were conducted. RESULTS: Among high risk patients undergoing TJA, 90% did not receive any pharmacological treatment for osteoporosis, 45% were not treated with vitamin D or calcium, and 88% did not receive bone density testing in the routine care period. Among patients with pre-existing osteoporosis undergoing TJA, 80% were not treated with any osteoporosis medications and 33% of these patients were not taking vitamin D or calcium. Female gender and past fracture history contributed to whether patients received screening and treatment. Patients with periprosthetic hip fractures have significantly higher FRAX scores compared to control THA patients. CONCLUSION: There are significant gaps in metabolic bone care of the geriatric TJA population regarding both screening and treatment. Metabolic bone care and risk identification with FRAX should be highly considered for TJA patients.