Continuous Passive Motion (CPM)
Chapter 15
Purposes
• Produce passive joint motion • Effects:
– Enhance nutrition – Increase metabolic activity – Stimulate tissue remodeling and regrowth of healing tissues:
• Articular cartilage • Tendons • Ligaments
Types of CPM devices
• Free Linkage • Anatomic • Nonanatomic
Free Linkage
• Moves the limb through ROM by grasping it proximal and distal to the joint • Adjustable to patient • Contraindicated for unstable joints
Anatomic Design
• Mimics natural motion of involved joint and the proximal joints • Most suitable for knees
Nonanatomical Design
• Does not attempt to replicate natural joint motion • Compensatory movement occurs between limb and CPM unit
Physiological Effects of CPM
• Encourages the remodeling of collagen along the lines of force • Reduces: – The negative effects of joint immobilization – Functional shortening – Cross linking of collagen – Capsular adhesions • Enhances the tensile strength of
– Tendons – Allografts – Skin
• Stimulate repair of articular cartilage
Physiological Effects
• Fluid pressures
– Extension:
• Most joint volume • Low pressure
– Flexion:
• Least joint volume • High pressure
• Changes in pressure creates a pumping effect
– Circulates synovial fluid – Assists in the removal of: • Hemarthrosis • Periarticular edema • Blood from tissues surrounding joint
Range of Motion
• Total end range time (TERT)
– Delivers a low load, prolonged stress – Increases ROM as TERT increases
• Helps patient overcome the apprehension of moving joint after surgery • Decreases rate of atrophy • Limits functional shortening of muscle • No increase on cardiovascular system
Joint Nutrition
• Stimulates circulation of synovial fluids • Increases nutrient uptake
– Meniscus – Articular cartilage
Edema Reduction
• Not clearly understood • Varies according to:
– The body part – Condition being treated
• The passive movement of the limb and the elevation of the body part could assist in venous and lymphatic return by milking the muscle
Pain Reduction
• Movement of joint activates the gate control pain theory • Other effects such as decreased edema could also decrease pain • Not used as an acute pain-control technique
Ligament Healing
• ACL does not receive the same nutritional benefits from CPM as cartilage because of its separate synovial lining • Effective in allograft-augmented medial collateral ligament reconstruction
Contraindications
• • • • • Unwanted joint motion and overstressing Unstable fractures Spastic paralyses Uncontrolled infection Deep Vein Thrombosis
Clinical Applications
• A CPM technician will use the manufacturers protocol to administer treatment following surgery • Precaution:
– CPM devices should not be used in the presence of flammable gases
Treatment Duration
• • • • Long term bouts: patient continuously attached 1-hour 3 times per day 6 to 8 hours a day post-surgery In home treatments with home visits by physical therapist