Abstract
Objective
We aimed to create an imaging biomarker for knee shape using knee dual-energy x-ray absorptiometry (DXA) scans and investigate its potential association with subsequent total knee replacement (TKR), independently of radiographic features of knee osteoarthritis and established risk factors.
Methods
Using a 129-point statistical shape model, knee shape (expressed as a B-score) and minimum joint space width (mJSW) of the medial joint compartment (binarized as above or below the first quartile) were derived. Osteophytes were manually graded in a subset of images and an overall score was assigned. Cox proportional hazards models were used to examine the associations of B-score, mJSW and osteophyte score with TKR risk, adjusting for age, sex, height and weight.
Results
The analysis included 37,843 individuals (mean age 63.7 years). In adjusted models, B-score was associated with TKR: each unit increase in B-score, reflecting one standard deviation from the mean healthy shape, corresponded to a hazard ratio (HR) of 2.25 (2.08, 2.43), while a lower mJSW had a HR of 2.28 (1.88, 2.77). Among the 6719 images scored for osteophytes, mJSW was replaced by osteophyte score in the most strongly predictive model for TKR. In ROC analyses, a model combining B-score, osteophyte score, and demographics outperformed a model including demographics alone (AUC = 0.87 vs 0.73).
Conclusions
Using statistical shape modelling, we derived a DXA-based imaging biomarker for knee shape that was associated with kOA progression. When combined with osteophytes and demographic data, this biomarker may help identify individuals at high risk of TKR, facilitating targeted interventions.
We aimed to create an imaging biomarker for knee shape using knee dual-energy x-ray absorptiometry (DXA) scans and investigate its potential association with subsequent total knee replacement (TKR), independently of radiographic features of knee osteoarthritis and established risk factors.
Methods
Using a 129-point statistical shape model, knee shape (expressed as a B-score) and minimum joint space width (mJSW) of the medial joint compartment (binarized as above or below the first quartile) were derived. Osteophytes were manually graded in a subset of images and an overall score was assigned. Cox proportional hazards models were used to examine the associations of B-score, mJSW and osteophyte score with TKR risk, adjusting for age, sex, height and weight.
Results
The analysis included 37,843 individuals (mean age 63.7 years). In adjusted models, B-score was associated with TKR: each unit increase in B-score, reflecting one standard deviation from the mean healthy shape, corresponded to a hazard ratio (HR) of 2.25 (2.08, 2.43), while a lower mJSW had a HR of 2.28 (1.88, 2.77). Among the 6719 images scored for osteophytes, mJSW was replaced by osteophyte score in the most strongly predictive model for TKR. In ROC analyses, a model combining B-score, osteophyte score, and demographics outperformed a model including demographics alone (AUC = 0.87 vs 0.73).
Conclusions
Using statistical shape modelling, we derived a DXA-based imaging biomarker for knee shape that was associated with kOA progression. When combined with osteophytes and demographic data, this biomarker may help identify individuals at high risk of TKR, facilitating targeted interventions.
| Original language | English |
|---|---|
| Article number | 100468 |
| Number of pages | 10 |
| Journal | Osteoarthritis and Cartilage Open |
| Volume | 6 |
| Issue number | 2 |
| Early online date | 15 Apr 2024 |
| DOIs | |
| Publication status | E-pub ahead of print - 15 Apr 2024 |
Bibliographical note
AcknowledgementsThe authors would like to express their gratitude to Dr. David Wilson, Consultant Interventional Musculoskeletal Radiologist and honorary Clinical Lecturer at The University of Aberdeen, for his valuable contribution to the development of the DXA-based osteophyte Atlas. They also extend their appreciation to all the participants of the UK Biobank study.
unding
This research was funded in whole, or in part, by the Wellcome Trust [Grant numbers: 209233/Z/17/Z, 223267/Z/21/Z]. BGF is funded by an NIHR Academic Clinical Lectureship. CL was funded by a Sir Henry Dale Fellowship jointly funded by the Wellcome Trust and the Royal Society (223267/Z/21/Z). NCH is supported by grants from Medical Research Council (MRC) [MC_PC_21003; MC_PC_21001] and the NIHR Southampton Biomedical Research Centre. AS was affiliated with the Bristol University at the time of the study conduct and is currently affiliated with Roche Diagnostics International, Clinical Development and Medical Affair. At the time this work was conducted MF was an employee at the University of Bristol. MF is now employed by Boehringer Ingelheim UK & Ireland.
Keywords
- Knee shape
- Osteoarthritis
- Statistical shape modelling
- Osteophytes