Knee pain, knee osteoarthritis, and the risk of fracture

• Published in: Arthritis and rheumatism 2006-08, Vol.55 (4), p.610-615
• Main Authors: Arden, Nigel K., Crozier, Sarah, Smith, Helen, Anderson, Frazer, Edwards, Christopher, Raphael, Helen, Cooper, Cyrus
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Biological and medical sciences; Diseases of the osteoarticular system; Double-Blind Method; Falls; Female; Fracture; Fractures, Bone - epidemiology; Fractures, Bone - prevention & control; Hip Fractures - epidemiology; Humans; Injections, Intramuscular; Injuries of the limb. Injuries of the spine; Knee Joint - physiopathology; Knee pain; Male; Medical sciences; Miscellaneous. Osteoarticular involvement in other diseases; Osteoarthritis; Osteoarthritis - complications; Osteoarthritis - drug therapy; Osteoarthritis - physiopathology; Pain - physiopathology; Placebos; Surveys and Questionnaires; Traumas. Diseases due to physical agents; Vitamin D - administration & dosage; Vitamin D - therapeutic use; Walking
• ISSN: 0004-3591; 0893-7524; 1529-0131; 1529-0123
• DOI: 10.1002/art.22088

Objective Patients with osteoarthritis (OA) have increased bone mineral density; however, the association between knee OA and fracture is controversial. Few data exist on the association between knee pain and fracture. We examined the association of knee OA and knee pain with fracture and falls in elderly men and women. Methods The study group comprised 6,641 men and women ages ≥75 years who participated in a 3‐year randomized controlled trial of intramuscular vitamin D therapy. Patients completed a questionnaire about knee pain and OA. Fracture and fall data were collected prospectively every 6 months. Results Knee pain prevalence and a clinician diagnosis of knee OA were 35.2% and 6.8%, respectively. A total of 436 incident nonvertebral fractures were reported, and 3,992 patients sustained a fall. Prevalent knee pain was associated with an increased risk of falls (hazard ratio [HR] 1.26, 95% confidence interval [95% CI] 1.17–1.36) and hip fracture (HR 2.0, 95% CI 1.18–3.37). Increasing severity of knee pain was associated with a greater risk of falls and hip fracture. Clinician diagnosis of knee OA was associated with an increased risk of nonvertebral fractures (HR 1.61, 95% CI 1.09–2.36). The increased risk of fracture was not substantially reduced by adjusting for falls, but was attenuated by adjustment for the use of walking aids. Conclusion Patients with a clinical diagnosis of knee OA and with knee pain have an increased risk of nonvertebral and hip fracture. This is not explained by the increased risk of falls, but is more likely to be due to the severity of falls sustained. Knee pain and OA should be regarded as independent risk factors for fracture.