Continuous Passive Motion(CPM)

Chapter 15

Purpose

Produce passive joint motion Effects:

Enhance nutrition Increase metabolic activity Stimulate tissue remodeling and regrowth of healing

tissues: Articular cartilage Tendons Ligaments

Specific to Body Area and Motion

Knee Flexion/Extension Wrist Flexion/Extension Wrist Radial/Ulnar Deviation

Finger Flexion/Extension

GH Flexion/Extension GH Internal/External Rotation

Types of CPM devices

Free Linkage Anatomic Nonanatomic

Free Linkage Design

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