Advice
Clinical and technical evidence
Clinical and technical evidence
A literature search was carried out for this briefing in accordance with the interim process and methods statement. This briefing includes the most relevant or best available published evidence relating to the clinical effectiveness of the technology. Further information about how the evidence for this briefing was selected is available on request by contacting mibs@nice.org.uk.
Published evidence
One study of 35 people is summarised in this briefing.
Further unpublished evidence was identified or provided by the company, including presentations, conference abstracts, patient testimonies, and manuscripts prepared or submitted for publication. These contain limited information but support the evidence in the 1 published study.
The clinical evidence and its strengths and limitations is summarised in the overall assessment of the evidence.
Overall assessment of the evidence
The limited evidence is supportive of the STAK tool. It shows that it can improve range of movement and patient-reported outcome measures. The study was done in the UK and is relevant to the NHS. However, it involves 1 NHS trust and a small number of patients. It is unclear how representative findings are and if they would be replicated across the NHS. The comparative evidence is limited to 8 weeks follow up. Further evidence generation could help to address these points.
Aspinall et al. (2020)
Study size, design and location
Prospective observational study in the UK of 35 adults after knee surgery who were prescribed intensive physiotherapy for stiffness by their surgeon. People were recruited consecutively in block allocations.
Key outcomes
The STAK tool made significant gains compared with control during the 8‑week treatment period in mean range of movement (30° compared with 8°, p<0.0005). It also improved Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC; 19 points compared with 3 points, p<0.0005), and Oxford Knee Scores (8 points compared with 3 points, p<0.0005).
After the 8-week treatment period using the STAK tool, people were followed up for varying lengths of time, up to 15 months. During this follow-up period there was a small decline of 2° in range of movement and continued improvements in the remaining Oxford Knee Scores and WOMAC scores. These changes were not statistically significant, and suggested improvements were maintained in the follow-up period.
Study feedback found that both groups followed their treatment. But, individuals were more actively engaged with the STAK tool (an average of 3 times a day at a 'very intense' level of stretch for an average of 13 minutes per session for 7 days a week compared with on average twice a day at a 'moderate intensity' level of stretch for 14 minutes per session for 4.8 days a week). People who used the STAK tool reported high acceptability for the intervention (mean score, 6.8/7); 98% were extremely likely to recommend it to a friend, and 93% considered that the STAK tool was wholly responsible for their change in knee range of movement.
Strengths and limitations
A randomised trial, even though randomisation was in blocks, with well-matched groups at baseline. People could not be blinded to treatment, and while the assessors were, it is possible that treatment details were disclosed to them. Only the STAK tool group was followed up after 8 weeks, so it is not possible to be certain that gains against controls were maintained. People in the STAK group were telephoned once a week to check that there were no problems using the device. This could constitute a further intervention that could have favoured the intervention group.
The study author is the inventor of the STAK technology.
Sustainability
The company claims the technology is reusable and the components of the device are stable for a minimum of 10 years. The materials used have been tested and proven to withstand chloro-clean, and have suitable mechanical strength for all intended purposes. The device was used by different patients in the published study.