Can Hip and Knee Arthroplasty Surgeons Help Address the Osteoporosis Epidemic?
Authors: Agarwal Amil R. , Malyavko Alisa , Gu Alex , Harris Andrew B. , Rao Sandesh , Sterling Robert , Golladay Gregory J. , Thakkar Savyasachi C. 
Published: July 2023

Abstract

Background
Osteoporosis is a known, modifiable risk factor for lower extremity periprosthetic fractures. Unfortunately, a high percentage of patients at risk of osteoporosis who undergo THA or TKA do not receive routine screening and treatment for osteoporosis, but there is insufficient information determining the proportion of patients undergoing THA and TKA who should be screened and their implant-related complications.

Questions/purposes
(1) What proportion of patients in a large database who underwent THA or TKA met the criteria for osteoporosis screening? (2) What proportion of these patients received a dual-energy x-ray absorptiometry (DEXA) study before arthroplasty? (3) What was the 5-year cumulative incidence of fragility fracture or periprosthetic fracture after arthroplasty of those at high risk compared with those at low risk of osteoporosis?

Methods
Between January 2010 and October 2021, 710,097 and 1,353,218 patients who underwent THA and TKA, respectively, were captured in the Mariner dataset of the PearlDiver database. We used this dataset because it longitudinally tracks patients across a variety of insurance providers throughout the United States to provide generalizable data. Patients at least 50 years old with at least 2 years of follow-up were included, and patients with a diagnosis of malignancy and fracture-indicated total joint arthroplasty were excluded. Based on this initial criterion, 60% (425,005) of THAs and 66% (897,664) of TKAs were eligible. A further 11% (44,739) of THAs and 11% (102,463) of TKAs were excluded because of a prior diagnosis of or treatment for osteoporosis, leaving 54% (380,266) of THAs and 59% (795,201) of TKAs for analysis. Patients at high risk of osteoporosis were filtered using demographic and comorbidity information provided by the database and defined by national guidelines. The proportion of patients at high risk of osteoporosis who underwent osteoporosis screening via DEXA scan within 3 years was observed, and the 5-year cumulative incidence of periprosthetic fractures and fragility fracture was compared between the high-risk and low-risk cohorts.

Results
In total, 53% (201,450) and 55% (439,982) of patients who underwent THA and TKA, respectively, were considered at high risk of osteoporosis. Of these patients, 12% (24,898 of 201,450) and 13% (57,022 of 439,982) of patients who underwent THA and TKA, respectively, received a preoperative DEXA scan. Within 5 years, patients at high risk of osteoporosis undergoing THA and TKA had a higher cumulative incidence of fragility fractures (THA: HR 2.1 [95% CI 1.9 to 2.2]; TKA: HR 1.8 [95% CI 1.7 to 1.9]) and periprosthetic fractures (THA: HR 1.7 [95% CI 1.5 to 1.8]; TKA: HR 1.6 [95% CI 1.4 to 1.7]) than those at low risk (p < 0.001 for all).

Conclusion
We attribute the higher rates of fragility and periprosthetic fractures in those at high risk compared with those at low risk to an occult diagnosis of osteoporosis. Hip and knee arthroplasty surgeons can help reduce the incidence and burden of these osteoporosis-related complications by initiating screening and subsequently referring patients to bone health specialists for treatment. Future studies might investigate the proportion of osteoporosis in patients at high risk of having the condition, develop and evaluate practical bone health screening and treatment algorithms for hip and knee arthroplasty surgeons, and observe the cost-effectiveness of implementing these algorithms.

Level of Evidence
Level III, therapeutic study.