CPM - In Recovery Mode

CPM - In Recovery Mode

By Razia Sanwari

CPM, or continuous passive motion, is a treatment process applied to exercise a joint post surgery or injury in order to prevent swelling and stiffness thus ensuring that the limb recovers completely and functions smoothly. It is a method applied to aid in recovery of the joint with the help of a mechanized device in a procedure by which the joint is rehabilitated.

CPM - In Recovery Mode

Instead of the normally-advised stretching and flexing exercises, your orthopedic surgeon is likely to suggest CPM which is applied by a machine that passively and repeatedly moves the injured joint for an extended period of time through a specified range of motion or ROM. The term ‘passive motion’ indicates that the device works to move the patient’s joint but not the muscles.

After Surgery/Injury

After a surgery or injury, there is pain in the joint that has been operated upon or hurt so movement will automatically be restricted. This will allow fluid to accumulate in and around the joint, tissue around the joint to become stiff and for scar tissue to form resulting in a joint with limited ROM and one which will require months of physical therapy to be normal again. There is histological proof which indicates that fibrosis may set in within four days of the onset of immobility. And within four weeks there will be formation of dense connective tissue if a normal joint stays immobilized.

The first six weeks after surgery are crucial. This is the period when the wound will see bleeding and accumulation of fluid or edema. Medically, the onset of stiffness is preceded by these four stages - bleeding, edema, granulation tissue and fibrosis. Due to edema, blood vessels dilate and leak plasma reducing the compliance of the tissues. This results in distension of the joint capsule and swelling of the periarticular tissues, which are tissues that surround the joint, thereby restricting full and normal movement of the joint.

Edema is followed by the formation of granulation tissue which deposits itself as a solid, extracellular matrix adding to the stiffness due to fluid accumulation and thus, further reducing ROM. Soon after, the granulation tissue becomes more dense leading to rigid, scar tissue with a high concentration of collagen type 1 fibers.

It is said that immobilization for an extended period of time can cause obliteration or degeneration of articular cartilage and loss of tensile strength in tendons and ligaments.

How does CPM work

CPM - In Recovery Mode

To prevent the setting in of the stiffness, doctors may advise that CPM be applied immediately after the surgery. This method serves to prevent arthrofibrosis after trauma or a surgery of the joint like the knee, elbow or joints of the hand, any joint which is likely to become stiff. This is the major clinical use of a CPM device today which acts like a mechanical splint and promotes healing of joint surfaces and soft tissue.

CPM works on the bleeding and edema by pumping the fluid away from the joint and the periarticular tissues. This action prevents the development of motion-limiting scar tissues and allows the periarticular soft tissues to stay normal without stiffness being allowed to set in.

A CPM device is motorized and designed to move the joint in a prescribed arc of motion for an extended period of time. It gently flexes the joint without the patient having to move it. No effort is at all required in this motion. The machine serves to continuously move the affected joint without assistance on a 24-hour basis.

When to Use

Experts strongly recommend that movement of the joint should begin on the very first day of the surgery. To begin with, the exercise should be slow but it needs to be continuous and as much as possible. And this passive motion should be carried on until swelling does not develop.

Some studies have indicated that a patient using CPM immediately after surgery needs less medication for pain than would otherwise require.

Uses of CPM

CPM - In Recovery Mode

CPM devices are useful in the rehabilitation of the shoulder, elbow, ankle, wrist, hand, following fractures of the knee joint, knee reconstruction after an injury or total knee replacement because of painful conditions due to arthritis. An orthopedic surgeon may recommend CPM soon after total knee replacement, arthroscopic ACL reconstruction, rotator cuff repair, tendon repair, joint manipulation, articular cartilage transplantation, articular cartilage microfracture and in the repair of the meniscus.

A CPM device may be used on an inpatient basis or in a homecare setting.

Possible Complications

There are a few possible complications from the use of a CPM. Research has indicated that there have been isolated cases of increased bleeding following CPM device usage. And there are contradictions about the effect of CPM on a wound with one study reporting increased wound healing complications because of CPM usage.

Therefore, it is strongly advised that a CPM device should be used only on doctor’s recommendations and under expert supervision.

CPM and Knee Replacement Surgery

After knee arthroplasty, CPM is usually applied on the belief that this mechanism increases recovery of the knee ROM and has other rehabilitative effect. However, recent studies have indicated that there is some benefit of CPM in the first few weeks after the knee surgery but after six weeks there appears to be no further change in the condition from the use of the machine. Hence, how effective a CPM device is on knee rehabilitation is not very apparent and the outcome of its use after knee surgery is still unclear.

CPM - In Recovery Mode

More research is required.

Different Types

The market is flooded with high quality CPM devices that may be used in the hospital or at home. They are safe and reliable and can be applied to speed up wound healing but purely on the advice of your orthopedic surgeon. Makers like Chattanooga and Kinetec USA specialize in these machines which have user-friendly functions and are easy to use. They can be transported easily and stored without taking up too much space. There are different types of CPM devices available for the hand, wrist, ankle, knee, shoulders and elbows providing anatomically correct extension and flexion.