The Ideal Prosthesis Selection

Numerous factors are taken into account when prescribing prostheses. First of
all, the physiatrist will try to determine what the (potential) activity level
is or will be. In addition, preferences of the patient are taken into account.
Thirdly, external factors may be of influence, for instance the policy of the
insurance company of the patient. Finally, scientific evidence regarding the
influence of a prosthesis on the walking pattern should be taken into account.
When looking in the literature with respect to which prosthesis should be
prescribed for which patient, a limited amount of studies are available. Based
on this, the CBO guideline 'Amputation and prosthetics of the lower extremity'
states that 'what type of prosthesis for which type of patient' is one of the
essential research questions for the foreseeable future.
In recent years, the added functionality of different prostheses has been
increasingly studied. However, usually overall results are presented and
relationships between the effect of the prosthetic knee and individual
characteristics are scarcely studied. Because of this, it is unknown which type
of patient benefited the most of the studied prosthetic knee.
Next to this, previous research almost exclusively focused on patients with a
stable gait pattern (usually one year after amputation is used as an inclusion
criteria). Because of this, little is known about the restoration of walking
ability. Knowledge of this is essential for the determination of the potential
functional activity level of the patient.
Finally, little is known about how the gait pattern of patients with an
amputation can be reliably quantified. Usually 10-15 steps are collected and
averaged and it is assumed that these steps are representative of the gait
pattern.
The TIPS project aims to gain insight into the added functionality of different
prosthetic knees and the restoration of the gait pattern, taken the above
stated concerns into account.

Part 1: Quantification of individual patient-prosthesis interactions
- Determination of the instantaneous effect of prosthetic knees with variable
biomechanical properties on the gait pattern of PULAs (Part Ia).
- Determination of the influence of the Total Knee versus an adaptive
prosthesis on the gait pattern of PULAs based on the relation between the
individual needs of the PULA and the proposed function of these prosthetic
knees (Part Ib).

Part 2: Restoration of walking ability within the first year after amputation
Exploration of the natural restoration of walking ability of PULAs within the
first year after amputation.

Part 3: Inter- and intrasession variability of gait
Determination of the inter- and intrasession variability of gait of PULAs.

Part 1
Crossover study

Part 2
Prospective observational study

Part 3
Observational study

Part 1a
Participants will walk with prosthetic knee from the following five categories
for a short period of time. The categories are:
- Constant resistance against flexion/extension and servo-assisted extension
(swing phase control). An example is, amongst others, the 3R20.
- Polycentric knee with dorsally placed joint of rotation without resistance
(stance phase control) in combination with constant damping against flexion and
servo-assisted extension (swing phase control). An example is, amongst others,
the 3R106.
- Polycentric knee with dorsally placed joint of rotation without resistance
(stance phase control) in combination with variable resistance and damping
against flexion/extension depending on angular velocity and servo-assisted
extension (swing phase control). An example is, amongst others, the Total Knee
2000.
- Single knee axis with variable resistance and/or damping based on ground
reactive force and flexion angle (stance phase control) in combination with
variable resistance and damping against flexion/extension depending on angular
velocity and servo-assisted extension (swing phase control). An example is,
amongst others, the Mauch SNS.
- Single knee axis with variable resistance and adaptive control (stance phase
control) in combination with variable resistance and damping against
flexion/extension and adaptive control (swing phase control). An example is,
amongst others, the Rheo Knee.
The order in which prosthetic knees are tested will be randomized.

Part 1b
Participants will walk with the Total Knee and an adaptive prosthetic knee for
a period of four weeks.
The order in which prosthetic knees are tested will be randomized.

Part 2
No intervention

Part 3
No intervention

The burden associated with participation is relatively small, as we focus
exclusively on walking. Participants are asked to walk multiple times (maximal
five minutes at a time).
In case participants are not fully accustomed to a prosthesis there is a risk
of falling. This risk, however, is comparable to the risk participants have in
daily life.
To reduce the risk of falling there will be an experienced physiotherapist
present during the measurements. He can assess the risk of falling at any
moment.