Kyrenia · Kuzey Kıbrıs
Continuous passive motion therapy
A continuous passive motion (CPM) device uses a motor to move a joint repeatedly through a preset range, most often after surgery. Passive means that the…
A continuous passive motion (CPM) device uses a motor to move a joint repeatedly through a preset range, most often after surgery. Passive means that the movement is not produced by the person's muscle force. CPM is used only when the surgical or clinical protocol considers it appropriate; it is not an automatic alternative to active exercise, walking and strength work.
What does CPM do—and not do?
The device cycles the joint between selected lower and upper angles at a set speed. It can provide controlled early movement, but does not functionally strengthen muscle, train balance or develop voluntary control.
Value varies by procedure. Reviews do not show a clear large lasting functional advantage from routine use after uncomplicated knee replacement, so it is not automatically required for everyone.
How are CPM settings chosen?
Starting range, speed, duration and daily use follow surgical restrictions, swelling, pain and wound status. Another patient's degrees and hours should not be copied.
Sharp pain, increased swelling or wound tension during progression leads to stopping and checking the plan. A higher angle is not automatically better.
How should a person be positioned?
The joint is aligned with the machine hinge and the limb is supported. Sliding, pressure points and straps that restrict circulation are avoided. Independent users learn start, stop and emergency controls.
Sleeping or unsupervised use should not occur without explicit guidance. Skin and circulation are checked periodically.
How does CPM combine with active rehabilitation?
When permitted, muscle activation, active motion, transfers, walking and functional exercise occur separately. Passive range gained in the machine does not prove control of that range.
Swelling, the active-passive gap, strength and gait remain key measures. The device continues only while serving a defined target.
When is CPM stopped or reviewed?
Increasing pain or swelling, pressure injury, numbness, wound concern or exceeding restrictions requires stopping. Calf pain, chest pain or breathlessness needs urgent assessment rather than a machine adjustment.
Use can end when active exercise maintains the target or no additional function is gained. Decisions follow measurements and protocol, not a purchased package.
Written by: Physiotherapist Harun Yıldırım · Medical review: Op. Dr. Hasan Gümüşdağ · Last updated: 16 August 2026
Frequently asked questions
Does CPM strengthen the knee?
No. It provides passive motion; voluntary exercise is needed for strength.
Can I increase the CPM angle myself?
Only within limits given by the surgeon or therapist. Sudden increases may not suit swelling or repaired tissue.
Is CPM required after every knee operation?
No. Need depends on procedure, protocol and target, and routine benefit is not equal in every case.
Can I sleep in a CPM machine?
Only with explicit clinical and device guidance because position, skin and safety require attention.
What if CPM increases pain?
Stop and check alignment, range, speed, duration, swelling and wound status. Severe or unexpected pain is reported.
Sources
Related pages
This page provides general information and does not diagnose a condition or replace an in-person medical assessment. The appropriate approach depends on individual assessment.