“Bone on bone pain” in the knee is a common description for the severe discomfort caused by advanced osteoarthritis, a progressive, degenerative joint disease. This condition occurs when the protective cartilage covering the ends of the bones has worn away significantly or completely deteriorated. Cartilage normally acts as a smooth, cushioned surface and shock absorber. Without it, the bones of the thigh and shin directly contact and rub against each other. This friction leads to inflammation, stiffness, and intense pain that worsens with activity or after rest. When conservative treatments are no longer sufficient, a specialized supportive device becomes necessary to help maintain mobility and reduce the mechanical stress on the joint.
The Unloader Knee Brace
The most effective device for mitigating bone on bone knee pain is the Unloader, or Offloader, knee brace, engineered specifically for unicompartmental osteoarthritis. Unlike standard hinged braces or simple compression sleeves, the Unloader brace is a semi-rigid or rigid orthosis designed to mechanically alter the knee’s biomechanics. It is constructed with external stems, hinges, and straps, often featuring a low-profile design. This brace is designed not just to support the joint, but to redistribute the weight-bearing forces acting on the knee. Unloader braces are typically prescribed medical devices for individuals with moderate to severe symptoms, ensuring they deliver the precise force needed to shift pressure away from the damaged area.
Mechanism of Pain Relief
The Unloader brace works by actively shifting the load away from the damaged compartment of the knee to the healthier compartment. This is achieved through the three-point leverage system. The system involves two points of contact on the thigh and calf shells, with a third point of pressure delivered by a dynamic force strap that crosses the knee.
This three-point force application applies a gentle, corrective angular adjustment to the joint, which creates space between the bones in the affected area. For instance, if the inner (medial) compartment is damaged, a valgus force is applied to move the knee slightly outward, reducing the compressive load on the painful side. By reducing the adduction moment, the brace functionally “unloads” the damaged surface. This biomechanical realignment decreases friction and contact between the exposed bone surfaces, providing immediate pain relief and improving functional mobility.
Criteria for Selecting a Brace
Selecting the correct Unloader brace relies heavily on ensuring an appropriate fit, which is the most important factor for both comfort and effectiveness. The brace must be measured and fitted by a professional to ensure the mechanical hinges and straps align precisely with the anatomy of the leg. A poorly fitted brace will fail to apply the necessary corrective force and may cause skin irritation or discomfort, leading to discontinued use.
The materials used in the brace’s construction are also important for daily wear, with lighter, low-profile designs promoting better compliance. Most modern Unloader braces are constructed from molded plastic, foam padding, and durable metal or carbon fiber struts for stability. Individuals with a higher activity level should prioritize robust designs that maintain structural integrity under heavy use. Many models incorporate adjustable tension dials that allow the user to fine-tune the unloading force based on their current activity or pain level.
Consulting a Specialist
Because the Unloader brace is a complex medical device designed to alter the body’s alignment, it requires a formal diagnosis and prescription. A physician, typically an orthopedist, must confirm the specific compartment of the knee that is affected, usually determined through a physical examination and X-ray imaging. The brace is only effective for unicompartmental osteoarthritis, meaning the damage is predominantly on one side of the joint. Once prescribed, the brace fitting process is often managed by a physical therapist or a certified orthotist. These specialists are responsible for taking precise measurements, adjusting the brace to achieve the optimal alignment, and instructing the patient on proper wear and care.