An observational study in Osteo Arthritis Knee, sponsored by Martini Hospital Groningen. Completed at 1 site in Netherlands. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-01-08.
Sponsored by Martini Hospital Groningen · Observational
The aim of this study was to investigate whether computer-assisted cryotherapy is effective in reducing postoperative pain and analgesics consumption, next to improving functional outcome and patient satisfaction after total knee arthroplasty (TKA). The hypothesis is that computer-assisted cryotherapy has positive effects on postoperative pain after TKA.
For this purpose a single-centre non-blinded trial was designed where two groups of patients were observed, a cold (cryotherapy) C-group and a regular (control) R-group. Depended on the week they were operated patients received either usual care (R-group) or computed-assesed- cryotherapy (odd or even week; week-on/week-off principle). Patients in the C-group received next to usual postoperative care computer-assisted cryotherapy for several hours a day during the first seven postoperative days (10-12 degrees Celcius).
Primary outcome was pain, monitored with the numerical rating scale for pain. Secondary outcomes were the use of opioid escape medication, function and swelling, monitored by active range of motion, timed up and go test and circumference measurements; several patient-reported outcome measures (short term 2 and 6 weeks; and longer term 6 and 12 months postoperative); and patient satisfaction, monitored by the numerical rating scale for satisfaction.
The study was conducted at the Orthopaedic Surgery Department of Martini Hospital, a teaching hospital in the Netherlands. All participants gave signed informed consent before participation. Patients with end-stage OA over the age of 18 who were scheduled for a TKA were invited to participate in this study. Exclusion criteria were rheumatoid arthritis, skin or other infections, vascular disease, other comorbidities on which cooling may have a negative effect, and strong preference for one of the treatment options. Patients were randomised into one of the two groups by a week-on/week-off principle. Patients who underwent TKA surgery in an even week received additional postoperative cryotherapy (C-group), those who had the surgery in an odd week received usual postoperative care (R-group). Surgery dates were scheduled in the usual way by the planning department of the hospital. Two weeks before surgery, patients were informed by phone as to which group they were assigned to. Both groups received the usual rapid recovery (RR) care and rehabilitation program, consisting of local infiltration analgesia during surgery, compressive bandaging for 24 h after surgery, and full weight-bearing mobilisation and active range of motion exercises starting on the day of surgery. Antibiotics were given preoperatively and postoperatively. All patients received thromboembolic prophylaxis for a period of six weeks. The Smith \& Nephew (Memphis, USA) posterior stabilized (PS) GENESIS II total knee system was used for the TKA.
For the CAC in the C-group, the ZAMAR ZHC-MG665A (ZAMAR, Vrsar, Croatia) was used during hospitalisation and the smaller CAC system ZAMAR ZT Cube (ZAMAR, Vrsar, Croatia) for the home situation. The CAC system was delivered to the patient's home before the day of the surgery. Both models had a touchscreen with pre-set programs, with parameters as shown in the cooling schedule. All patients received a personal cooling brace, the ZAMAR Wrap, which transferred cold onto the skin and deep tissue around the knee. Patients in the C-group were instructed to cool the operated knee during the first seven postoperative days. The schedule they received was based on a schedule used by Thijs et al. Patients were allowed to deviate from this schedule, but were asked to document the actual cooling time and temperature in a log.
The study population is recruited from one large peripheral hospital in the Netherlands, the Martini Hospital.
Exclusion Criteria:
Postoperative treatment using computed-assisted-cryotherapy in the first week postoperative in addition to usual care
Device: Computed-assisted-cryotherapy
Postoperative treatment according to usual care
cryotherapy device
Numeric rating scale (NRS) pain score in rest
range 0-10, where a higher score indicates more pain
Time frame: assessed at 6 weeks postoperative
Numeric rating scale (NRS) pain score in rest
range 0-10, where a higher score indicates more pain
Time frame: at baseline, daily during the first 7 days, after 2 weeks, and 6 and 12 months postoperative
Numeric rating scale (NRS) pain scores while loading
range 0-10, where a higher score indicates more pain
Time frame: at baseline, daily during the first 7 days, after 2 and 6 weeks, and 6 and 12 months postoperative
Opioid use
The amount of opioid use in case of excessive pain
Time frame: daily during the first week after surgery
active Range of Motion
in degrees
Time frame: at baseline and at 6 weeks postoperative
Timed Up and Go
In seconds. Measure of functional mobility.
Time frame: at baseline and at 6 weeks postoperative
Knee circumference
in centimeters
Time frame: at baseline and at 6 weeks postoperative
Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire
Without the sports and recreation domain. Range 0-100, where a higher score indicates less symptoms.
Time frame: preoperative and 2 and 6 weeks postoperative
Work, Osteoarthritis en joint-Replacement Questionnaire (WORQ)
Measure of work ability (functioning). Range 0-100, where a higher score indicates less functional limitations.
Time frame: preoperative and 2 and 6 weeks postoperative
EuroQol 5D (EQ5D) - 5 point Likert scale
Index score (0-1, closer to 1 indicates better health related quality of life); visual Analogue Scale scale about the self-perceived health status (0-100, higher indicates better self-perceived health status).
Time frame: preoperative and 6 and 12 months postoperative
Oxford knee scores
Range 0-48, where a higher score indicates less symptoms.
Time frame: preoperative and 6 and 12 months postoperative
KOOS-PS scores (Knee Injury and Osteoarthritis Outcome Score - Physical Function Short Form)
Range 0-100, where a higher score indicates less symptoms
Time frame: preoperative, and 6 and 12 months postoperative
Numeric rating scale (NRS) satisfaction
patient's satisfaction with the outcome after surgery at that time point, range 0-10, where a higher score indicates more satisfaction
Time frame: 2 and 6 weeks postoperative, and 6 and 12 months postoperative
anchor question: patient perceived change in pain
the degree in which a patient experiences an improvement in pain compared to baseline (7 point Likert scale: much worse, worse, slightly worse, no change, slightly better, better, much better)
Time frame: 6 and 12 months postoperative
anchor question: patient perceived change in functioning
the degree in which a patient experiences an improvement in functioning compared to baseline (7 point Likert scale: much worse, worse, slightly worse, no change, slightly better, better, much better)
Time frame: 6 and 12 months postoperative
Numeric rating scal (NRS) satisfaction cryotherapy
Only for the patients who used the Computer-assisted-cryotherapy device: patient's satisfaction with cryotherapy. Range 0-10, where a higher score indicates more satisfaction.
Time frame: 1 week postoperative
Complications/Serious adverse events
Keep record of the complications that occurred
Time frame: from baseline until 12 months postoperative
Plan to share: Yes — Only deidentified data will be available upon reasonable written request in conjunction with appropriate data use agreement.
This study is completed, as verified in Jan 2025. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Martini Hospital Groningen