An orthosis is a device that provides support to or improves the function of a moveable part of the body and essentially they control abnormal movement or allow restricted normal movement. Orthosis is a Greek word meaning to make straight
Purpose of Splints
- To immobilise or stabilise joints (static splints)
- Protection
- To put joints to rest
- To decrease inflammation
- To decrease pain
- To prevent undesired motion
- To resolve fixed joint contracture, e.g. serial casting
- To substitute for lost muscle function
- To substitute for loss of a digit
- For mobilisation or traction to joints (dynamic splints)
- To resolve tendon tightness
- To resolve joint contracture
- To increase activity range on motion to given joints
- To increase muscle strength
Dynamic Splints
- Dynamic splinting to gain motion is most appropriate to use during the proliferative stage of wound healing as increased cellular activity occurs at the healing site, the gentle prolonged force of dynamic splinting influences the direction and alignment of collagen fibres
- To be effective a dynamic splint must not be applied until the inflammatory stage is subsiding so that the dynamic forces do not prolong the inflammatory response
- Also the tension must be of such low magnitude so as not to tear or force the tissues and thus stimulate the inflammatory response, causing more oedema and then more fibrosis
- Precautions
- Pressure areas over bony prominences
- Insensate hands or limbs
- Thin skin, e.g. Rheumatoid Arthritis
- Vascular insufficiency
- Edema
Aims and demands of knee orthoses
- Prophylactic or support devices that support the injured knee or weak ligaments
- Rehabilitation devices used after surgery
- Functional devices that stabilise and support the deformed joint
Experiments show the centre of rotation remains practically unchanged up to almost 90 of flexion scarcely rising or falling and only moves backwards.The height of the centre of rotation above the knee is 20 mm +/- 3 mm
On X-Rays the compromise axis lies in the middle of the intercondylar notch approximately at the proximal insertion of the posterior cruciate ligament