Comparisons of Mechanical Properties of Tendon Structures

Phase 1 Study: Comparison of Electromechanical Delay Phase 2 Study: Research in Viscoelasticity of Tendon Structures Phase 3 Study: Effects of Exercise Training in the Mechanical Properties

We assume the etiology of patellofemoral pain syndrome is related to mechanical properties of tendon structures of the vastus medialis obliquus and vastus lateralis. Consequently, we will measure the electromechanical delay and some viscoelastic parameters of the two muscles. Besides, we will also investigate the effects of exercise training to the mechanical properties of the muscles.

Study Overview

• Status: Unknown
• Conditions: Patellofemoral Pain Syndrome
• Intervention / Treatment: Procedure: leg press training; Procedure: isokinetic training

Detailed Description

Patellofemoral pain syndrome (PFPS) is a common knee disorder. From the literature review, one may find inconsistent results among different research or clinical studies on the effect of therapeutic exercise for the patients with PFPS. A possible reason for the disagreement might be lack of a clear etiology of patellofemoral pain. At present, the most widely accepted concept for the genesis of patellofemoral pain is abnormal lateral tracking of the patella. One factor that causes this maltracking is soft tissue imbalance around the patella. Previous studies demonstrating the inconsistency of the amplitude of muscle activity and the timing of muscle firing for vastus medialis obliquus (VMO) and vastus lateralis (VL) may contribute to the imbalance of soft tissue. Another neuromuscular condition, however, the electromechanical delay of VMO and VL in patents with PFPS was not investigated extensively. We hypothesized that people with PFPS would have longer electromechanical delay of VMO than that of VL. The objective of this three-year project is to compare the electromechanical delay of VMO with that of VL in people with PFPS for the first year. In the second year, we will further investigate the viscoelastic properties of tendon structures, the key components induced this electromechanical delay, of VMO and VL in vivo. In the last year, we will research the effect of an exercise program on the mechanical properties of VMO and VL in people with PFPS.We expect to recruit 30 patients with PFPS as an experimental group and 30 healthy individuals as a control group in the both first and second years. In the third year, we will recruit 60 patients with PFPS, 30 of them to receive a specific exercise program and the others are in the control group.

The evoked electromechanical delay of VMO is defined as the time interval between the time when VMO receiving an electrical stimulation and the onset time of patellar movement due to the VMO contraction. The viscoelastic properties of tendon structures are investigated by an ultrasonographic study under voluntary contraction conditions. The torque output during isometric knee extension at 80° of flexion is measured by a dynamometer. The subject is instructed to produce a gradually increasing force from relaxed status to maximal voluntary contraction within 5 seconds, followed by a gradual relaxation also within 5 seconds. Simultaneously, the elongation of the deep aponeurosis of the VMO or VL is caught by the ultrasonic image which is synchronized with the torque signal by a clock timer for subsequent analysis. The stiffness, Young's modulus and hysteresis of the tendon structures are calculated to represent its viscoelastic properties.

Finally, the subject is prescribed an 8-week exercise program by EN-dynamic machine to perform knee extension from 45° to 0° of flexion. The training outcome is assessed with electromechanical delay of VMO and VL. And we will also investigate the effect of the exercise program on the mechanical properties of tendon structures.

• Study Type: Interventional
• Enrollment (Anticipated): 120
• Phase: Phase 1

Contacts and Locations

Study Locations

• Taiwan
  • Taipei, Taiwan, 100
    • Recruiting
    • Kinesiology Laboratory
    • Contact: Mei-Hwa Jan, Master; Phone Number: 886-2-33228138; Email: mhjan@ntu.edu.tw

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: No older than 49 years (Child, Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. Below 50 years old.
2. Subjects have at least two of five conditions of knee pain: to squat down, to go or down stairs, to keep prolong sitting position, to be palpated the joint cartilage of patella, to be test by Clark sign.
3. Subjects have the symptoms for 3 months at least.

Exclusion Criteria:

1. Subjects have the other knee disorder in addition to PFPS.
2. Subjects had ever received operations of knee in past 3 months.
3. Subjects have neurological disease.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 1	Procedure: leg press training; quadriceps muscle strengthening. 30min/ 3times/ week
Active Comparator: 2	Procedure: isokinetic training; quadriceps muscle training. 30 min/ 3 times/ week

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
electromechanical delay	minisecond

Secondary Outcome Measures

Outcome Measure	Time Frame
quadriceps muscle force	second
the displacement of deep aponeurosis of vasti muscles	second

Collaborators and Investigators

• Sponsor: National Taiwan University Hospital
• Investigators: Study Director: Mei-Hwa Jan, Master, School and Graduate Institude of Physical Therapy,NTU

Publications and helpful links

General Publications

• Cowan SM, Hodges PW, Bennell KL, Crossley KM. Altered vastii recruitment when people with patellofemoral pain syndrome complete a postural task. Arch Phys Med Rehabil. 2002 Jul;83(7):989-95. doi: 10.1053/apmr.2002.33234.
• Kubo K, Kanehisa H, Kawakami Y, Fukunaga T. Elastic properties of muscle-tendon complex in long-distance runners. Eur J Appl Physiol. 2000 Feb;81(3):181-7. doi: 10.1007/s004210050028.
• Chen HY, Chien CC, Wu SK, Liau JJ, Jan MH. Electromechanical delay of the vastus medialis obliquus and vastus lateralis in individuals with patellofemoral pain syndrome. J Orthop Sports Phys Ther. 2012 Sep;42(9):791-6. doi: 10.2519/jospt.2012.3973. Epub 2012 Aug 2.

Study record dates

Study Major Dates

• Study Start: December 1, 2006
• Primary Completion (Actual): March 1, 2007
• Study Completion (Anticipated): September 1, 2009

Study Registration Dates

• First Submitted: March 22, 2007
• First Submitted That Met QC Criteria: March 22, 2007
• First Posted (Estimate): March 23, 2007

Study Record Updates

• Last Update Posted (Estimate): January 30, 2008
• Last Update Submitted That Met QC Criteria: January 28, 2008
• Last Verified: December 1, 2006

More Information

Terms related to this study

• Keywords: patellofemoral pain syndrome; viscoelasticity; mechanical properties; electromechanical delay; VMO
• Additional Relevant MeSH Terms: Joint Diseases; Musculoskeletal Diseases; Patellofemoral Pain Syndrome
• Other Study ID Numbers: 9561703048