BRAKE RESPONSE TIME BEFORE

AND AFTER TOTAL KNEE ARTHROPLASTY

Tracking Possible Effects of the Surgery Technique on Motor Performance:

Report of Two Cases

Carlos J. Marques

1,2

, Rui Santos

, Hugo Gamboa

, Frank Lampe

, João Barreiros

and Jan Cabri

Faculty of Human Kinetics, Technical Universitty of Lisbon, Lisbon, Portugal

Physikal Therapy and Rehabilitation Department, ENDO-Klinik Hamburg, Hamburg, Germany

Joint Replacement Center, Schön Klinik Hamburg Eilbek, Hamburg, Germany

Physics Department of the Sciences and Technology Faculty, New University of Lisbon, Lisbon, Portugal

Department of Physical Performance at the Norwegian School of Sport Sciences, Oslo, Norway

Keywords: Total Knee Replacement, Minimally Invasive Surgery, Brake Response Time, Reaction Time, Automobile

Driving.

Abstract: After total knee arthroplasty (TKA) patients often ask when they can resume car driving. This question was

the aim of some studies in the past, however no study was found on the possible effects of different surgery

techniques on brake response time (BRT). A randomized controlled trial on the effects of two surgery

techniques (minimally invasive vs. standard approach) on BRT was designed. In this paper the motor

performance of two female patients was compared. Surgery had different effects on the mean BRT of both

Patients. The mean BRT of the MIS Patient wasn’t increased 7 days after surgery, while the BRT of the

Patient undergoing standard surgery was increased by 46.8% at the same time.

1 INTRODUCTION

Patients undergoing total knee arthroplasty (TKA)

frequently ask when they can resume car driving.

Six studies on this topic were published in the past

years (Dalury et al., 2010, Liebensteiner et al., 2010,

Marques et al., 2008a, Marques et al., 2008b,

Pierson et al., 2003, Spalding et al., 1994). All

studies investigated the effects of TKA on brake

response time (BRT), an important human factor

used in accident prevention research.

The results document a BRT increase after right

TKA. The time frame needed for the BRT to return

to preoperative values varied and ranged from 8

(Pierson et al., 2003) to 4 weeks (Dalury et al.,

2010). In the study by Dalury and colleagues (2010),

where the patients were submitted to “contemporary

TKA with less tissue disruption”, the BRT of all

patients returned to preoperative values 4 weeks

after surgery. A small group of patients reached the

preoperative values already 2 weeks after surgery.

The BRT can be fractionated in reaction time

(RT) and movement time (MT). The RT, also called

neurological time, is the time required for stimulus

perception, response selection and response

initiation. The MT can be subdivided in foot transfer

time (FTT) and brake pedal travelling time (BPTT).

In the studies where the components of the BRT

(RT and MT) were investigated (Spalding et al.,

1994, Marques et al., 2008b, Marques et al., 2008a,

Dalury et al., 2010) it was observed that ten days

after TKA the central components of the task were

not affected once RT was not changed.

Total knee arthroplasty seems to affect peripheral

aspects related with the execution of the movement

and the soft tissue lesion may be the cause of such

performance impairments.

Minimal invasive surgery (MIS) techniques for

TKA have been used for several years as an

alternative to standard approaches. Supporters of

MIS techniques go from the assumption that a

smaller soft tissue injury with a reduction of the

muscle quadriceps lesion leads to a faster

419

J. Marques C., Santos R., Gamboa H., Lampe F., Barreiros J. and Cabri J..

BRAKE RESPONSE TIME BEFORE AND AFTER TOTAL KNEE ARTHROPLASTY - Tracking Possible Effects of the Surgery Technique on Motor

Performance: Report of Two Cases.

DOI: 10.5220/0003790904190422

In Proceedings of the International Conference on Bio-inspired Systems and Signal Processing (BIOSIGNALS-2012), pages 419-422

ISBN: 978-989-8425-89-8

 2012 SCITEPRESS (Science and Technology Publications, Lda.)

rehabilitation with better early functional outcomes,

less pain and shorter stay duration. To the best of our

knowledge we don’t know of any available data on

the effects of different surgery techniques on motor

performance while executing an emergency brake in

a car simulator. The purpose of this study is to

compare the effects of MIS and Standard approach

for TKA on BRT components. Once the study is

ongoing the data of two cases will be reported.

2 METHODS AND MATERIALS

2.1 Design

A randomized controlled trial with one between-

subject factor (surgery technique: MIS or Standard)

and one within-subject factor (time: one day before

and 7 days, 30 and 40 days after surgery) was

designed (Marques et al., 2011). After consent to

participate the patients were randomly assigned to

MIS or standard approach surgery. The patients

were blinded to the surgery technique they

underwent and they all received the same standard

physiotherapy treatments.

One experienced orthopaedic surgeon performed

all surgeries. In the operation room a concealed

envelope was opened and the surgeon got to know

which technique he would have to perform.

The MIS technique used was the mini-midvastus

approach (Haas et al., 2006). The peri-patellar

approach with inversion of the patella was standard.

Independently from the surgery technique all

operations were performed with the use of the

OrthoPilot navigation system and all patients got a

Columbus total knee endoprosthesis (BBraun

Aesculap, Germany).

The study protocol was approved by the Ethics-

Committee of the Federal State of Hamburg,

Germany (Project Nr.: PV3349). The trial

registration number at the German Clinical Trial

Database (DRKS) is: DRKS00000552.

2.2 Participants

The patient selection is taking place at the Schön

Klinik Hamburg Eilbek in Hamburg, Germany. The

patients addressed the clinic for elective primary

right TKA and were asked if they were car drivers.

If the patient drove regularly (at least once a week)

he/she was informed about the study and asked for

consent.

The patient selection started on January 10

2011 and is still ongoing. Eleven patients have

signed the informed consent until now, of which the

complete data of 8 Patients is available: MIS n=5 (4

male; 1 female); Standard approach n=3 (1 male; 2

female). Because the number of cases is still small

and the distribution of male and female patients in

the groups is unlike, we will present only the

primary outcome results of two female patients (Pat.

A and Pat. B).

2.3 Instruments/ Equipment

The patients performed the emergency brakes in a

car simulator (Fig.1) which was built based on a

European middle class car an already used in two

former studies (Marques et al., 2008a, Marques et

al., 2008b).

Figure 1: Car simulator with bioPlux Research system.

The data acquisition system consists of a bioPlux

Research system with wireless connectivity via

Bluetooth (Plux –Wireless Biosignals, S.A.), one

trigger to command the stimulus light (red LED)

turn on/off and two load cells connected with the

break and accelerator pedals.

2.4 Study Outcomes

The primary outcomes of the study are the brake

response time (BRT), which is time frame between

the onset of the red LED and the achieving of a

brake force on the brake pedal of 150N (ms). The

BRT was fractionated in reaction time (RT), foot

transfer time (FTT) and brake pedal travelling time

(BPTT).

2.5 Procedures

The assessments took place in a closed room to

avoid secondary distraction sources. A trained

physiotherapist performed all tests.

After sitting down in the car simulator the

patients were required to adjust the seat in order to

BIOSIGNALS 2012 - International Conference on Bio-inspired Systems and Signal Processing

420

find a comfortable position. A simple and a more

complex

Figure 2: Mean BRT values across the four measurements.

task were used to assess the components of BRT. At

each measurement day patients performed 5 practice

and 10 test trials for each task.

2.6 Data Analysis

Two types of signals were collected: the digital

signal from the light trigger and the force signals

from the accelerator and brake pedal load cells. The

digital signal was used to slice the signals in the 10

break trials for each task. The force signals were

calibrated considering that in the initial instant the

foot is not pressing any of the pedals and the

acquired value in the initial 100ms was considered

the zero of the load cells.

After the pre-processing steps, the onset points of

the force signals were detected by applying a signal-

independent algorithm, which marks significant

events in a signal, based on a morphological analysis

approach (Santos et al., 2012) and the values of the

variables were detected.

3 RESULTS

Patient B is 15 years older then patient A. Despite

that difference patient B had faster baseline

performances in both tasks when compared with

patient A.

Table 1: Demographic data of both patients.

Patient A Patient B

Age (y) 61 76

Body weight (Kg) 71 74

Stature (cm) 167 175

Technique MIS Standard

The effects of TKA on BRT are different when

comparing the data of both cases in the simple task

Figure 3: Mean RT values across the four measurements.

(Fig. 2). Seven days after surgery the mean BRT of

Patient B (Standard) had increased by 46.8% while

the mean BRT of Patient A remained practically

unchanged (decreased 0.08% from the first to the

second measurement). From the second to the third

measurement the mean BRT had decreased by

25.7% and 17.3% for patients A and B respectively.

Thirty-two days after surgery patient A performed

on average 201.1ms quicker then at baseline, while

the mean BRT of patient B was still 115.1ms

increased when compared with baseline.

The BRT increased due to an MT increase. The

RT (Fig. 3) decreased for both patients across the

time, with exception of patient B, who’s RT had

increased by 22.6% from the first to the second

measurement.

The analysis of the MT components (FTT and

BPTT) revealed that the BRT increased mainly due

to an increase of the FTT. The FTT (Fig. 4) had

increased by 57.8% (189.7ms) and 53.7% (144.6ms)

from the first to second measurement respectively

for patient A and B. At 40 days the mean FTT

values of both patients were still over baseline (see

Figure 5).

The BPTT decreased across the time for Patient

A, however, it increased by 65% for patient B

between the 1

and second measurement (Fig. 6),

showing that surgery techniques might have had

different effects on this variable.

4 DISCUSSION

Total knee Arthroplasty reduces pain and increases

function and quality of live in patients with knee

impairments resulting from osteoarthritis. Many

patients undergoing TKA want to know when they

can resume car driving after surgery.

The preliminary data of two patients suggests

that the surgery technique might have an influence

on BRT recovery after TKA.

BRAKE RESPONSE TIME BEFORE AND AFTER TOTAL KNEE ARTHROPLASTY - Tracking Possible Effects of the

Surgery Technique on Motor Performance: Report of Two Cases

421

Figure 4: Mean FTT values across the four measurements.

Figure 5: Mean BPTT values across the four

measurements.

The mean BRT of the MIS Patient was not increased

7 days after surgery, while the BRT of the Patient

undergoing standard surgery was increased by

46.8% by same time. Our results reinforce the

results by Dalury and colleagues (2010).

The components of MT (FTT and BPTT)

characterize two distinguished parts of the leg

movement. While during the FTT the leg is being

moved in an open system, with the foot having no

contact with the pedals, during the BPTT the leg is

being moved in a closed system, with the foot

pressing the brake pedal and the knee making an

extension. The performance pattern of the patients in

the open system (FTT) is very similar (Fig. 4), with

both patients showing a performance increase after

surgery followed by a decrease. On the other hand,

in the closed system (BPTT), the patient’s

performance provides an interesting difference, with

the MIS patient having no performance impairments

after surgery (Fig. 5). The eversion of the patella

during the standard approach may be the reason

behind the BPTT differences (Majima et al., 2011).

In order to find out, whether the observed trends

are related with the surgery technique the patients

underwent and not due to inter-subject variations, a

bigger sample is necessary.

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