Computer controlled cooling aftercare in patients with total knee arthroplasty

Cooling of the joint is a proven modality in the postoperative treatment of
pain and swelling after a total knee arthroplasty.
An abundance of applications exists, yet the most used options are (reusable)
icepacks, bags of frozen peas as well as computer controlled cooling devices.
As of yet, several reviews have not succeeded in pointing out the most
effective method. Smaller studies have pointed out several advantages of
computer controlled cooling: effective reduction of pain and therefore a
smaller intake of analgesics (most notably morphine-derivates, resulting in
lesser post-operative nausea and vomiting). A better range of motion and lesser
swelling as well as improved patient wellbeing are other great advantages of
efficient application of computer controlled cooling1 (compared to the current
conservative therapy with analgesics and icepacks).

The Zamar ZT Cube is a medical device based on heat exchange for cryotherapy
and thermotherapy. With an anatomical knee wrap adjusted to the patient*s knee,
cryotherapy is offered using continuous-cold flow through the pad during
several cooling sessions per day. In the first seven post-surgery days,
cryotherapy is applied to the post-operatively often swollen and inflammated
joint. It has been suggested that the reduction in swelling as well as a more
mildly occurring inflammatory reaction result in lesser pain, smaller intake of
analgesics with its accompanying side effects as well as better patient
satisfaction.

With this study we want to assess the efficacy of computer controlled cooling
in the aftercare in patients who underwent primary total knee arthroplasty in
addition to our regular aftercare.

Primary Objective:
The primary objective of this study is to assess the efficacy of computer
controlled cooling on postoperative pain in rest in the first 7 days of
recovery, measured with the NRS score.

Secondary Objectives:
* Assess the effect of compute controlled cooling on the use of analgesics.
* To compare the overall quality of life in patients with regular aftercare
combined with computer controlled cooling to patients with regular aftercare.
The Quality of Life will be measured by using standardized questionnaires
being: EQ-5D, NRS for patient satisfaction, KOOS-ps and a OKS.
* Range of motion of the affected knee compared with the healthy knee
* NRS-pain in activity

The chosen study design is a parallel study. Two groups of patients will
receive either regular aftercare (physical therapy, analgesics) combined with
computer controlled cooling or regular aftercare combined with regular cooling
therapy (icepacks). During the first seven postoperative days, patients will be
followed up in both clinical and out-patient setting.

Since there is no means of blinding the computer controlled cooling therapy, it
is not possible to create a double-blind study. The amount of time and
preparation required for a computer controlled cooling treatment prohibits
randomized treatment assignment. However, the approach of patients is unbiased
and purely based on their planned surgery (a weekly alternating scheme will be
in effect: patients in even numbered weeks will receive computer controlled
cooling, patients in odd numbered weeks will receive regular aftercare or vice
versa).

Patients will receive - in addition to our regular medicinal aftercare *
computer controlled cooling of the operated joint using the Zamar ZT Cube. For
several hours per day the knee will be cooled to a temperature between 10 and
12 degrees Celsius using the thermal pad.
On the day of surgery, patients will be cooled for 6 hours postoperatively,
followed by a 4 hour evening session and a 4 hour nightly session. At least 2
hours are in between every cooling session.
The first postoperative day, a 2 hour morning and 2 hour afternoon cooling
session are followed by a 4 hour evening and an optional 4 hour nightly
session. This scheme is continued unto day 7, however from day 2 the nightly
cooling session is optional.

Risks: negligible
Burden: during the first seven postoperatieve days a total time of 74 hours of
cooling of the joint on which surgery was performed. During the first seven
days four times daily patients will register their NRS-pain and consumption of
analgesics.