Journals
Response by Dr. Andy Bush to article published in Osteoporosis International
I want to address an article published last year in the Journal Osteoporosis International which is considered to be one of the premier journals in the academic realm of bone health:
Maryan Bobelyak, Jan Vaculik, Jan J. Stepan, Bone mineral density assessment using Radiofrequency Echographic Mult Spectrometry (REMS) in patients before and after total hip replacement, Osteoporosis International, https://doi.org/10.1007/s00198-025-07685-w
The publication of this article has caused an uproar in the REMS community, not because it challenged the use of REMS but unfortunately because of the obvious errors in how the examiners performed their REMS assessment.
Academic discussion is essential for the advancement of knowledge, and it is actually a good thing that there are finally articles written that ask questions about REMS technology. It seemed that up to now REMS was being ignored. However, for academic discourse to be beneficial and productive, it is of utmost importance that the information presented be correct; otherwise, the discussion will result in misinformation. The concern of such an article persisting in the literature as a reliable source of information is that it will inevitably be cited resulting in the further propagation of misinformation. This is what is happening with the Bobelyak et al, article
The authors, Bobelyak et al, claimed to have performed a REMS assessment on a hip that was replaced – a THA. Anyone who routinely does REMS assessments knows that it is technically impossible to assess a THA with REMS. I addressed these concerns in a letter that wrote to the Editorial Board of Osteoporosis International as did many other users of REMS. As of June 28, 2026, I have not heard back from the Board. I am posting that letter:
September 20, 2025
Osteoporosis International
Editorial Board
RE: Article
Dear Editorial Board:
After reading the recent article on the use of REMS in assessing BMD prior to and following THA surgery, I have multiple concerns about the validity of the results documented in the article. Based on these concerns it is my opinion that the Editorial Board of Osteoporosis International should review the paper to determine its credibility.
The authors documented that they were able to measure the BMD of the femoral neck in a group of selected patients who were indicated for and underwent successful THA surgery both prior to and following the surgery. The results that were published indicated that they were able to obtain BMD measurements of the femoral neck utilizing REMS technology prior and following THA and that the BMD of the femoral neck following THA surgery was statistically lower than the BMD prior to surgery. As an accomplished REMS user with > 2000 REMS assessments over 4 years, I find that result improbable.
In addition to routinely using REMS in my bone health program, I am an orthopedic surgeon who has performed several thousand THA surgeries over my 30-year career. In a correctly performed THA, the femoral neck is resected to 1 cm. of the lesser trochanter. That technique is demonstrated in fig. 1 - image B, the postoperative x-ray. It is clearly visible that there is no femoral neck. Also, it can be ascertained from the x-ray that the prosthesis utilized was a proximal-fill type prosthesis that was implanted using a press-fit technique (not cemented). The preparation of the proximal femur following neck resection includes the machining of the proximal femur to remove cancellous bone to allow the prosthesis to establish 3-point fixation with the femur. The points of contact include the calcar, the lateral cortical bone below the trochanter and the medial cortical bone below the lesser trochanter. As is demonstrated by the x-ray, the prosthesis in addition to making the appropriate points of contact, fills the entirety of the femoral canal. Obtaining a sonographic assessment of the trabecular bone anywhere in this construct would be impossible.
In my years of performing REMS, I was never able to image a THA in the way described by the authors. I have successfully performed REMS evaluations on individuals with spinal hardware and cement, hip resurfacing, and ORIF of hip or proximal femoral fractures. In those cases, the anatomy of the bone being evaluated was preserved and there was enough native bone preserved to allow for the normal processes involved in REMS image recognition and data acquisition to proceed per established protocols. In individuals following THA, and in an individual with an altered anatomy of the proximal femur following a hip fracture treated non-surgically with a resulting malunion I could not obtain the necessary bone profile to allow for REMS assessment.
The method of bone identification and BMD and Fragility Score determination is detailed in:
1 – Casciaro S, Peccarisi M, Pisani P, et al (2016) An advanced quantitative echosound methodology for femoral neck densitometry. Ultrasound Med Biol, 42(6):1337–1356. https:// doi. org/ 10. 1016/j. ultrasmedbio. 2016.01.024
2 – Conversano F, Franchini R, et al (2015) A novel ultrasound methodology for estimating spine mineral density. Ultrasound Med Biol 41(1):281–300. https:// doi. org/ 10. 1016/j. ultrasmedbio. 2014. 08. 017
3 – Echolight REMS Technology Sheet
The process is multi-step including the filtering, identification, enhancement, amplification, and morphologic evaluation of the RF signals. Once the frames of the sonographic dataset have been analyzed the number of identified interfaces is assessed and if sufficient to yield a statistically reliable result, the diagnostic calculations are performed. As was noted by one of the authors, “The algorithm contains a spectral validation step. In this step, the spectra not similar enough to one of the reference models should be rejected.” However, the authors concluded that the “unique quality” of the titanium implant was “not rejected” and they were able to complete the REMS assessment. However, it is well known that metal (including titanium) has a sonographic signal very different from bone and due to the density of the metal, ultrasound will not penetrate the prosthesis and a “shadow” will be cast. Also, the anatomic profile of the native femoral neck is completely different from that of a THA, it is highly unlikely that any of the processing steps could have proceeded. The images from the REMS scan provided by the authors also are concerning. Fig 1. images C & D show what appears to be a bone surface interface and they are identical even though fig 1. image D is the postoperative image where the femoral neck was resected. Surprisingly, there are no sonographic findings that would be consistent with the presence of a metal implant. The bone interface presented in fig. 1 images C & D are not consistent with images of the femoral neck but possible are images of the femoral shaft.
REMS is a novel technology for assessing bone structure that holds potential for a transformative effect on the field of bone health. It is important to correctly assess this technology to ensure that it is used appropriately and that the results of academic studies are clinically valid. Thank you for considering my request and for addressing my concerns.
Respectfully,
Andrew Bush MD