Naslov
A New Method for Determining the Leg Length Discrepancy

Autori
Obrovac, Karlo ; Vrhovski, Zoran ; Nižetić, Josip ; Mutka, Alan ; Vuković-Obrovac, Jadranka ;

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, prošireni sažetak, znanstveni

Izvornik
Book of Abstract - International Central European ISPO Conference / - , 2018, 22-22

Skup
International Central European ISPO Conference

Mjesto i datum
Portorož, Slovenija, 20.09.2018. - 22.09.2018

Vrsta sudjelovanja
Plenarno

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
LEG LENGTH DISCREPANCY

Sažetak
INTRODUCTION: Determining the length of the lower extremities is an important part of orthosis practice. Although there are a number of methods existing, no one yields enough reliable results. A special problem lies in the fact that the common discrepancy measurement methods do not consider the load distribution, which should be expected to be symmetric. In patients with Leg Length Discrepancy (LLD) the center of mass (CoM) always deviates from the expected position. Impossibility to determine CoM position prevents the implementation of appropriate measures to compensate difference in height. For this purpose, a special device is developed to precisely determine this parameter. AIMS: LLD is an condition that involves a difference in length between the lower extremities. Patients with LLD have a displaced centre of mass, which causes pain and inefficient and energy-consuming gait. The accuracy and reliability of LLD estimation is essential for determining the required treatment of compensating for LLD. The existing methods of LLD estimation, are not reliable. Furthermore, they may subject patients to radiation and do not account for the displacement of CoM of the human body. For these reasons, we developed a digital system that would precisely measure and determine the difference in the length of the lower extremities. METHODS: The system for compensating for LLD based on the estimation of CoM of the human body has been developed. This system consists of two 3-RPS (Revolute- Prismatic-Spherical) parallel manipulators with moving force plates. A patient with LLD stands on the left and right force plate. Sensors measure the center of pressure (CoP) of the foot and the total force that the foot exerts on the force plate. The patient’s shorter leg creates a greater load for the force plate. LLD compensation is performed by increasing the height of the force plate below the shorter leg by means of a manipulator. The height of the force plate is increased up to the moment when the measured forces of the left and right force plate become equal. The difference in height of the force plates represent the amount of LLD and may be used for producing the insole or sole lift for compensating for LLD. RESULTS: Experimental measurements show that the manipulator can be used to move the CoM to a position indicating that the human body is in balance. CONCLUSION: A prototype of the system for compensating for LLD was made. It includes two 3-RPS parallel manipulators with a moving force plate. Experimental results indicate that LLD may be compensated by balancing the human body, which sets CoM in the correct position. Future work on the system for compensating for LLD will include automated human body balancing using a visual feedback.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne tehničke znanosti, Kliničke medicinske znanosti

POVEZANOST RADA