Wolfgang Fitz - Brigham and Women’s Hospital, Boston, MA, USA
Pinak Shukla - Great Plains Orthopedics, North Platte, NE, USA
Ling Li - Brigham and Women’s Hospital, Boston, MA, USA
Richard D. Scott - Brigham and Women’s Hospital, Boston, MA, USA

Background: Techniques that allow early muscle activation, such as closed kinetic chain (CKC) and open kineticchain (OKC) exercises, may play a beneficial role in the early rehabilitation of the reconstructed knee. However,current rehabilitation regimens have not been shown to reverse post-operative quadriceps activation failureand weakness. To investigate whether patients who use a continuous active motion (CAM) device that followsclosed kinetic chain principles have better early post-operative functional improvements than patients who use acontinuous passive motion (CPM) device that follows the principles of open kinetic chain principles. A prospectiverandomized controlled trial with non-blinded study staff. A tertiary care clinic at a teaching hospital. A total of 110patients signed the consent form and 83 patients participated in the study.Methods: Patients were randomly assigned to use either the CPM device for 4 hours daily for 3 weeks (controlgroup), or a CAM device for 3 sessions of 20 minutes for 3 weeks (intervention group), starting 24 hours afterknee replacement surgery.The primary outcome measure was to identify the superiority, inferiority, or equivalenceof one device at week 4 after knee arthroplasty using various functional outcome measures such as kinesthesia,quadriceps strength, coordination, general orthopaedic outcome measures and narcotic consumption.Results: At 4 weeks, all outcome measurements were comparable between the two groups, with the exceptionof sit-to-stand test: in the treatment group the time was significantly shorter compared to the control group(P=0.016). Balance was significantly better in both control (P=0.001) and treatment group (P=0.032) comparedto prior surgery.Conclusion: Most clinical centers would like to expedite functional recovery of knee arthroplasty patients withoutincreasing the risk of falls. We observed balance and kinesthesia improvements after surgery using eitherdevice which may be important to benefit fast recovery programs. Further research is warranted to see whetheradditional active closed kinetic chain exercised following knee replacement surgery could improve specificfunctional outcomes such the observed sit-to-stand test.

Knee arthroplasty, Post-op, Proprioception, Quadriceps strength