Mobilization within 24 hours post-TKA significantly reduces the risk of DVT

After adjusting for certain risk factors, early mobilization reduced the risk for DVT over threefold.

Patients who begin walking within 24 hours after total knee arthroplasty had a significantly lower incidence of deep venous thromboembolism compared to patients who begin mobilization on the second postoperative day, according to a study by researchers in Australia.

"Our results show that early mobilization can be achieved after conventional [total knee arthroplasty] when a multidisciplinary protocol involving the surgeon, anesthetist, nursing staff and physiotherapist is instituted," the authors reported.

"In our study, the incidence of DVT (deep venous thromboembolism) fell from 27.6% to 1% after the institution of an early mobilization protocol, a difference which was highly significant," they wrote.

E.O. Pearse, FRCS(Orth), and colleagues in New South Wales, evaluated the effect of an early mobilization protocol on the rate of DVT in 97 patients (122 knees) with a mean age of 68.7 years. They compared the incidence of DVT among these patients to an historical control group of 98 patients (125 knees) with a mean age of 68.8 years.

Both groups were similar in age, gender, the number of simultaneous bilateral total knee arthroplasties (TKA) and the number of significant medical conditions, the authors noted.

Their results appear in the British edition of the Journal of Bone and Joint Surgery.

Investigators found that 90 of the 97 patients (92.8%) in the early mobilization group began walking within 24 hours after surgery. Of these, 89 patients progressively increased the amount of walking throughout the day and over subsequent days.

Among controls, 20 patients (20.4%) began walking within 24 hours after surgery, but 11 had a reduction in walking ability due to nausea, syncope or poor pain control, the authors reported.

Among the 247 TKAs in the 195 total patients, investigators found 28 DVTs overall, of which 25 (89%) were distal calf and three (11%) were proximal, according to the study.

Only one patient in the early mobilization group experienced DVT, the authors noted.

In addition to a significantly lower DVT rate, patients in the early mobilization group used less patient-controlled analgesia and required less morphine than control patients, "which suggested that they did not have more pain," they reported.

The authors noted that there were several significant differences between the groups for postop venous thromboembolism (VTE), including history of previous VTE, obesity, venous stasis, hormone replacement therapy, spinal anesthesia and cemented implant fixation.

However, "When we adjusted for other risk factors, the risk of developing DVT if patients were in the early mobilization group was approximately 30 times lower than if they were in the control group," they wrote.

"When other risk factors were adjusted for, patients who began walking within 24 hours were over three times less likely to develop a DVT than those who began walking after 24 hours," they added.

For more information:
Pearse EO, Caldwell BF, Lockwood RJ, Hollard J. Early mobilisation after conventional knee replacement may reduce the risk of postoperative venous thromboembolism. J Bone Joint Surg Br. 2007;89-B:316-322.