Continuous passive motion after primary total knee arthroplasty. Does it offer any benefits?

Area of Science:

• Orthopedic surgery
• Rehabilitation medicine
• Biomedical engineering

Background:

• Total knee arthroplasty (TKA) is a common procedure for end-stage knee osteoarthritis.
• Postoperative rehabilitation aims to restore function and range of motion.
• Continuous passive motion (CPM) is a widely used modality in TKA recovery.

Purpose of the Study:

• To evaluate the effectiveness of continuous passive motion (CPM) in improving postoperative function and range of movement after total knee arthroplasty (TKA).
• To compare different CPM protocols (0-40 degrees vs. 0-70 degrees) against a no-CPM control group.

Main Methods:

• A prospective randomized controlled trial involving 53 patients (57 knees) undergoing TKA.
• Patients were allocated to three groups: no CPM, CPM 0-40 degrees, or CPM 0-70 degrees for 48 hours postoperatively.
• All patients received identical physiotherapy; assessments were conducted preoperatively, at one week, and one year postoperatively.

Main Results:

• At one week, the 0-70 CPM group showed a statistically significant increase in flexion and total range of movement compared to the no-CPM group.
• At one year, no significant differences were observed in flexion, range of movement, fixed flexion deformity, or functional outcomes among the three groups.
• Patients using CPM experienced a significant increase in analgesic requirements and greater postoperative blood drainage, particularly in the 0-70 CPM group.

Conclusions:

• Continuous passive motion (CPM) does not offer significant long-term advantages in improving function or range of motion after total knee arthroplasty (TKA).
• The use of CPM is associated with increased blood loss and higher analgesic requirements post-TKA.
• Current evidence suggests that CPM may not be a beneficial adjunct to standard physiotherapy following TKA.