Use of Drop and Dangle Rehabilitation Protocol to Increase Knee Flexion Following Total Knee Arthroplasty: A Comparison with Continuous Passive Motion Machine
Anuwat Pongkunakorn MD*, Duangrak Sawatphap MSN*
Affiliation : * Department of Orthopeadic Surgery, Lampang Hospital and Medical Education Center, Lampang, Thailand
Background : There are variations in the type of rehabilitation program and duration of using the continuous passive motion
(CPM) machine to increase range of motion (ROM) following total knee arthroplasty (TKA).
Objective : To compare the outcomes of the ‘drop and dangle’ (D&D) protocol vs. a 3-hour daily CPM for the purpose of
increasing flexion following TKA.
Material and Method: A prospective non-concurrent controlled intervention study was conducted on patients who underwent
primary TKA at Lampang Hospital from December 2009 to August 2011 (D&D group, n = 36) and from September 2011 to
December 2012 (CPM group, n = 33). The same surgeon using the same prosthesis design performed all surgeries. The legs
in D&D group were placed into the knee immobilizer at 70° flexion and removed on postoperative day 1 (POD1). The passive
ROM exercise was then started by dropping the affected leg over the bedside, and gently flexing and bending the knee with the
help of the unaffected leg to achieve maximal flexion. The legs in the CPM group were immobilized with a Jones bandage in
full extension for 24 hours, and then placed into CPM machine for three, 1-hour per day sessions. The clinical data were
statistically compared between the two groups.
Results : Patient baseline characteristics in both groups were not different. The D&D group had more average passive flexion
in POD1 (67.0°+14.2° vs. 59.1°+3.2°, p<0.001) and POD2 (76.6°+14.2° vs. 69.8°+13.3°, p = 0.008). Higher rates of
flexion were observed in PODs 3-7 but they were not significant. Flexion at discharge in the D&D group was 100.6°+6.8°
and 96.4°+10.2° in the CPM group (p = 0.005). At 6 weeks, rates of flexion in both groups were similar (D&D 99.8°+10.4°,
CPM 103.9°+10.4°, p = 0.138). Rates of flexion were also similar at 1 year (D&D 112.0°+10.4°, CPM 111.6°+12.6°, p =
0.892).
Conclusion : D&D protocol provided more passive knee flexion than the use of CPM in the first two days after TKA and at
discharge. These differences were not significant at 6 weeks and 1 year.
Keywords : Rehabilitation, Total knee arthroplasty, Continuous passive motion, Range of motion, Flexion
