Periarticular Bone Mineral Density Predicts Structural Progression of Knee Osteoarthritis Independently of Static Alignment

Grace H. Lo¹, Jeffrey B. Driban², Lori Lyn Price³, Charles Eaton⁴, Michael T. Strayhorn⁵ and Timothy E. McAlindon⁶, ¹VA HSR&D Center for Innovations in Quality, Effectiveness and Safety; Medical Care Line and Research Care Line; Department of Medicine, Michael E. DeBakey VA Medical Center, Baylor College of Medicine, Houston, TX, ²Rheumatology, Tufts Medical Center, Boston, MA, ³Clinical Care Research, Tufts Medical Center, Boston, MA, ⁴Center for Primary Care and Prevention, Memorial Hospital of Rhode Island, Providence, RI, ⁵VA HSR&D Center for Innovations in Quality, Effectiveness and Safety; Department of Medicine, Michael E. DeBakey VA Medical Center, Baylor College of Medicine, Houston, TX, ⁶Tufts Medical Center, Boston, MA

Meeting: 2015 ACR/ARHP Annual Meeting

Date of first publication: September 29, 2015

Keywords: Alignment and osteoarthritis

Session Information

Date: Tuesday, November 10, 2015

Title: Epidemiology and Public Health Poster III (ACR): Gout and Non-Inflammatory Musculoskeletal Conditions

Session Type: ACR Poster Session C

Session Time: 9:00AM-11:00AM

Background/Purpose: Individuals with a greater medial to lateral tibial periarticular bone mineral density (M:L paBMD) and static malalignment have greater risk for osteoarthritis (OA) progression. As these risk factors are inter-related, we aimed to evaluate whether M:L paBMD is associated with OA progression, independent of static alignment, which would suggest bone as a therapeutic target.

Methods: This was a study nested within two ancillary studies to the Osteoarthritis Initiative (OAI); therefore the visit for dual x-ray absorptiometry (DXA) was the OAI 30 or 36 month visit, for static alignment was mostly the 12 month visit, and for OA progression (longitudinal medial joint space narrowing (mJSN)) between the 24 and 48 month visits. Knee DXAs generated M:L paBMD using proprietary software. Hip-knee-ankle (HKA) angles (static alignment) were measured on long limb films. mJSN (OARSI grade) were assessed using PA semi-flexed radiographs. Knees with 24-month mJSN of 3 were excluded as they were not eligible for mJSN worsening.

Only evaluating one knee per person, usually the right knee unless contraindicated, we generated Pearson’s correlations between HKA and M:L paBMD. We also performed logistic regression with predictors of M:L pa BMD quartiles and outcomes of worsening of mJSN between the 24 and 48 month visits (including within OARSI grade worsening). Models were adjusted for HKA quartiles, age, sex, and BMI. The Cochrane Armitage Test assessed for statistical significance of trends. We performed a sensitivity analysis of only neutrally aligned knees, defined as HKA between -2° and 2°.

To further evaluate the influence of M:L paBMD, eliminating the influence of HKA, we used the residual of M:L paBMD regressed on HKA, representing the uncorrelated aspect of M:L paBMD unrelated to static alignment in logistic regression models.

Results: 419 participants were included, with a mean age of 63.8 +9.2 years; BMI of 29.4 +4.8 kg/m²; 52% male. At the OAI 24 month visit, 60 (14%), 68 (16%), 158 (38%), 122 (29%), and 11 (3%) had Kellgren and Lawrence grades of 0 – 4 respectively. 45% of knees were neutrally aligned.

M:L paBMD and HKA were correlated; R = 0.64 (p<0.0001); greater M:L paBMD was associated with greater varus alignment. Those with greater M:L paBMD had greater odds of mJSN progression, even in fully adjusted models (Table). Sensitivity analyses of only neutrally aligned knees were similar. Analyses evaluating M:L paBMD uncorrelated with HKA also supported a relationship with mJSN progression.

Table. Relationship of ML:pa BMD with mJSN progression, crude and adjusted models.
		Prevalence of mJSN progression	Unadjusted Odds Ratios	Adjusted Odds Ratios¹	Adjusted Odds Ratios²
M:L pa BMD quartiles	Quartile 1 (lowest)	3/102 (2.9%)	Referent	Referent	Referent
	Quartile 2	8/107 (7.5%)	2.7 (0.7 – 10.3)	1.7 (0.4 – 6.8)	1.5 (0.4 – 6.3)
	Quartile 3	15/104 (14.4%)	5.6 (1.6 – 19.8)	3.1 (0.8 – 11.8)	2.8 (0.7 – 10.8)
	Quartile 4 (highest)	30/106 (28.3%)	13.0 (3.8 – 44.3)	5.5 (1.5 – 20.6)	4.8 (1.2 – 18.6)
			p for trend <0.0001	p for trend = 0.0006	p for trend = 0.002
¹Adjusted for HKA quartiles
²Adjusted for HKA quartiles, age, sex, and BMI

Conclusion: Higher relative paBMD is associated with greater structural progression, even after adjustment for static alignment, a known correlate of periarticular BMD and predictor of progression. These findings suggest that treatments targeting periarticular bone, not focused solely on static realignment, may ultimately be protective of OA progression.

Disclosure: G. H. Lo, None; J. B. Driban, None; L. L. Price, None; C. Eaton, None; M. T. Strayhorn, None; T. E. McAlindon, None.

To cite this abstract in AMA style:

Lo GH, Driban JB, Price LL, Eaton C, Strayhorn MT, McAlindon TE. Periarticular Bone Mineral Density Predicts Structural Progression of Knee Osteoarthritis Independently of Static Alignment [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/periarticular-bone-mineral-density-predicts-structural-progression-of-knee-osteoarthritis-independently-of-static-alignment/. Accessed .

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