Abstract
Objectives
DXA scans may offer a novel means of evaluating radiographic knee osteoarthritis (rKOA) in large population studies and through opportunistic screening. We aimed to develop and apply a semi-automated method for assessing rKOA using ∼20,000 knee DXA images from UK Biobank (UKB) and assess its face validity by checking for expected relationships with clinical outcomes.
Methods
Right knee DXA scans were manually annotated for osteophytes to derive corresponding grades. Joint space narrowing (JSN) grades in the medial joint compartment were determined from automatically measured minimum joint space width. Overall rKOA grade (0–4) was determined by combining osteophyte and JSN grades. Logistic regression was employed to investigate the associations of osteophyte, JSN, and rKOA grades with knee pain and hospital-diagnosed knee osteoarthritis (HES-KOA). Cox proportional hazards modelling was used to examine the associations of these variables with risk of subsequent total knee replacement (TKR).
Results
Of the 19,595 participants included (mean age: 63.7), 19.5% had rKOA grade ≥1 (26.1% female; 12.5% male). Grade ≥1 osteophytes and grade ≥1 JSN were associated with knee pain, HES-KOA, and TKR. Higher rKOA grades were linked to stronger associations with these clinical outcomes, with the most pronounced effects observed for TKR. HRs for the association of rKOA grades with TKR were 3.28, 8.75, and 28.63 for grades 1, 2 and 3–4, respectively.
Conclusions
Our DXA-derived measure of rKOA demonstrated a progressive relationship with clinical outcomes. These findings support the use of DXA for classifying rKOA in large epidemiological studies and in future population-based screening.
DXA scans may offer a novel means of evaluating radiographic knee osteoarthritis (rKOA) in large population studies and through opportunistic screening. We aimed to develop and apply a semi-automated method for assessing rKOA using ∼20,000 knee DXA images from UK Biobank (UKB) and assess its face validity by checking for expected relationships with clinical outcomes.
Methods
Right knee DXA scans were manually annotated for osteophytes to derive corresponding grades. Joint space narrowing (JSN) grades in the medial joint compartment were determined from automatically measured minimum joint space width. Overall rKOA grade (0–4) was determined by combining osteophyte and JSN grades. Logistic regression was employed to investigate the associations of osteophyte, JSN, and rKOA grades with knee pain and hospital-diagnosed knee osteoarthritis (HES-KOA). Cox proportional hazards modelling was used to examine the associations of these variables with risk of subsequent total knee replacement (TKR).
Results
Of the 19,595 participants included (mean age: 63.7), 19.5% had rKOA grade ≥1 (26.1% female; 12.5% male). Grade ≥1 osteophytes and grade ≥1 JSN were associated with knee pain, HES-KOA, and TKR. Higher rKOA grades were linked to stronger associations with these clinical outcomes, with the most pronounced effects observed for TKR. HRs for the association of rKOA grades with TKR were 3.28, 8.75, and 28.63 for grades 1, 2 and 3–4, respectively.
Conclusions
Our DXA-derived measure of rKOA demonstrated a progressive relationship with clinical outcomes. These findings support the use of DXA for classifying rKOA in large epidemiological studies and in future population-based screening.
| Original language | English |
|---|---|
| Article number | rkaf009 |
| Journal | Rheumatology Advances in Practice |
| Early online date | 20 Jan 2025 |
| DOIs | |
| Publication status | E-pub ahead of print - 20 Jan 2025 |