Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT02569931 |
| Other study ID # |
15.0068 |
| Secondary ID |
15/SC/0512 |
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
December 2015 |
| Est. completion date |
December 2021 |
Study information
| Verified date |
March 2020 |
| Source |
St George's, University of London |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
The principal objective of the study is to find out which everyday activities make the
kneecap unstable in people with patellofemoral instability.
Analysing how a patient with an unstable kneecap walks will help us to determine if surgery
is successful in these patients by seeing if better scores on patient questionnaires are
found in patients following surgery and whether these patients also have a better pattern of
walking.
The investigators aim to use cameras and pressure pads to see how patients walk before and
after surgery and see how this compares to patient scores on the questionnaires.
If the investigators find that patients walk better after surgery they can justify that
surgery is worthwhile for the patient and cost effective for the NHS.
Description:
Recruitment strategy:
Patients referred to a specialist patellofemoral clinic with an unstable kneecap(s) will be
approached by the student and asked whether they would be interested in participating in the
study (study group). Participants will be considered eligible for the study group if they
have had two or more episodes of kneecap dislocation or many episodes of instability with at
least one of the following: a feeling that the kneecap will dislocate with pressure,
tenderness along the inner side of the knee and/or abnormal movement or position of the
kneecap.
They will be given a Patient Information Sheet (PIS) and be given time during the clinic to
ask questions about the study. During this first appointment as per routine current clinical
practice they will have an X-ray of their knee and fill in standard questionnaires to score
their knee function and pain (Norwich Patellofemoral Instability score, Kujala score,
PainDetect score, catastrophising score). The patient's knees will also be examined by the
consultant and a record made of the clinical findings. As per routine practice, a magnetic
resonance imaging (MRI) scan of both knees will be organised for 4 weeks after the original
appointment and measurements of knee shape recorded. A total of 32 patients will be invited
to join the study to assess the movement of the kneecap in patients with kneecap instability.
A group of normal knees (control group) will be studied to compare the findings from students
aged 18 to 50 years at St George's University of London allowing both age and gender to be
matched to the study group . Students with no previous history of knee problems will be
eligible to join the control group.
Inclusion criteria for both groups includes age 18-50 years, English language speakers, able
to use public transport or drive.
Exclusion criteria for both groups includes pregnancy, breast feeding, inability to give
informed consent, inflammatory arthropathy, osteoarthritis.
All participants in both the study and control groups will be provided with a Participant
Information Sheet (PIS) outlining the study design, objectives, procedures, data management
and dissemination plans. Participants will have a minimum of seven days to consider their
participation in this study.
If a participant expresses an interest in participating, and after time to read, consider and
discuss the PIS in clinic, they will be provided with an appointment at the MSk Lab at
Imperial College. At the start of the assessment the participant will be asked about their
potential eligibility based on the pre-defined eligibility criteria and will be provided with
a further opportunity to ask any questions about the study. If they are still interested in
participating, the potential participant will be asked to complete three Consent Forms and
they will be enrolled in the study.
Data Collection:
Each patient participant will complete a Norwich Patellar Instability (NPI) Score
questionnaire, a Kujala Patellofemoral Disorders Score, a PainDetect score and a
Catastrophising score which are validated questionnaires. Baseline data recorded prior to
testing will include: presence of joint hypermobility syndrome (Beighton score), age, gender,
duration of symptoms, frequency of kneecap dislocation, knee range of motion, MRC (Medical
Research Council) muscle strength (flexion and extension), previous patellofemoral joint
surgery, family history of patellar instability and whether patellar instability is
unilateral or bilateral. Basic demographic data for multi-variate regression analysis (e.g.
Body Mass Index data) will also be collected, along with measurements such as leg length /
height required for Hof scaling.
Testing Procedure:
Both the control and study group will have gait analysis measurements performed as a baseline
for data collection. After a six minute acclimatization period at 4km/h on the instrumented
treadmill (Kistler Gaitway, Kistler Instrument Corporation, Amherst, NY), the speed is
increased until either the subject feels uncomfortable, or the walking performance
deteriorates. The procedure generally takes 12 minutes of continuous walking. Following the
flat ground assessment, the inclination is then increased in 5° increments at a steady 4
km/h, until either the subject feels uncomfortable, or the walking deteriorates. The
treadmill is then ramped to an inclination of 7° downhill. The subject is then asked to walk
initially at the same 4 km/h, and then at 0.5 km/h increments until they either feel
uncomfortable, or the walking performance deteriorates.
At all incremental intervals of speed and inclination, data on the way participants walk are
collected for both limbs with a by special plates under the treadmill track. Body weight
scaling for leg length are also applied to the outputted mechanical data to correct for
differences. All data are subject to averaging and filtering to handle the large amount of
continuous data the machine captures, normally entailing a minimum of six steps for each
limb.
The subject will be asked to reproduce activities that have been associated with subjective
instability (e.g. running sideways, hopping, jumping, turning to look over a shoulder ) to
determine if the subjective feeling of instability correlates with physiological changes in
measurements captured on the instrumented treadmill. Electrical sensors on the skin will be
used to detect muscle activity.
For the study group during corrective surgery to deepen the groove, special markers and three
dimensional scanning will allow recording of kneecap movement without disturbing underlying
tissues to see if there is a statistically significant measurable difference, and if this
correlates to the change in performance/symptom scores.
Six months after surgery for the study group, gait analysis will be repeated at the MSk Lab
as previously outlined to determine the effect of surgery. The patients will be asked again
at this stage to fill in a Kujala and NPI score. It is anticipated that study subjects and
controls will be recruited over six months with data collection finished by a year from
enrolment of the first patient into the study.
Data Analysis:
The primary hypothesis of this study is that there will be a direct relationship between
shape of the kneecap groove and participants' walking performance. This will be tested
formally by comparing the measurements taken of the kneecap and groove shape, and those from
the measurements of gait. The aim will be to see if surgery improves gait and stops the
kneecap dislocating.
Study dissemination:
The findings of the study will be fed back to participants. Presentation of study findings
will be made at a local level with submission of a presentation to a regional meeting and
nationally prior to submission to journals offering open access publishing to allow
dissemination to other professionals and the public.
