Stress Shielding
Bone resorption that occurs when an implant bears more load than the surrounding bone, leading to decreased bone density and potential implant loosening.
Full Definition
Stress shielding is a biomechanical phenomenon that occurs when a metallic implant, due to its higher elastic modulus, bears a disproportionate amount of mechanical load compared to the surrounding bone tissue. According to Wolff's law, bone adapts to mechanical demands, and when normal physiological stresses are reduced, bone remodels by decreasing density and strength. This process is particularly relevant in joint replacement surgeries where stiff implants can lead to proximal bone resorption around the implant stem. In orthopedic rehabilitation, stress shielding has important implications for long-term implant survival, activity recommendations, and monitoring protocols. Prevention strategies include implant design modifications, appropriate activity levels to maintain bone stimulation, and careful monitoring through regular imaging and bone density assessments.
Usage
Usage note: Distinguish from osteolysis; emphasizes the biomechanical cause of bone loss.
In Context
- "Serial radiographs revealed evidence of stress shielding around the femoral stem at five years post-operatively." — Long-term follow-up assessment
- "The rehabilitation program emphasized impact activities to minimize stress shielding effects around the implant." — Post-arthroplasty exercise prescription