Osteoporosis, Osteoarthritis, and Subchondral Insufficiency Fracture: Recent Insights

Abstract

The increased incidence of osteoarthritis (OA), particularly knee and hip OA, and osteoporosis (OP), owing to population aging, have escalated the medical expense burden. Osteoarthritis is more prevalent in older women, and the involvement of subchondral bone fragility spotlights its association with OP. Notably, subchondral insufficiency fracture (SIF) may represent a more pronounced condition of OA pathophysiology. This review summarizes the relationship between OA and OP, incorporating recent insights into SIF. Progressive SIF leads to joint collapse and secondary OA and is associated with OP. Furthermore, the thinning and fragility of subchondral bone in early-stage OA suggest that SIF may be a subtype of OA (osteoporosis-related OA, OPOA) characterized by significant subchondral bone damage. The high bone mineral density observed in OA may be overestimated due to osteophytes and sclerosis and can potentially contribute to OPOA. The incidence of OPOA is expected to increase along with population aging. Therefore, prioritizing OP screening, early interventions for patients with early-stage OA, and fracture prevention measures such as rehabilitation, fracture liaison services, nutritional management, and medication guidance are essential.

Keywords: bone mineral density; osteoarthritis; osteoporosis; osteoporotic fracture; subchondral insufficiency fracture.

Figure 1

Mechanism of joint deterioration. All joint deterioration cases begin with micro-damage to the subchondral bone. Late-stage osteoarthritis (OA) develops as a reparative response to micro-damage. Subchondral insufficiency fractures (SIFs) are characterized by extensive subchondral damage. SIF can progress to secondary OA due to collapse. Severe inflammatory response to fracture fragments leads to rapidly destructive coxopathy. ↑, increase; ↑↑↑, dramatic increase; ↓, decrease.