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Patellofemoral Pain SyndromeNCT07730437

Effects of Clamshell Exercises in Addition to Standardized Physical Therapy in the Management of Patellofemoral Pain Syndrome

A study testing Standardized Physical Therapy and Standardized Physical Therapy with Clamshell Exercise in people with Patellofemoral Pain Syndrome and Anterior Knee Pain, run by Ibadat International University, Islamabad at 1 site in Pakistan.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

This randomized controlled trial aims to evaluate whether adding clamshell exercises to standardized physical therapy provides greater improvements in pain and knee function than standardized physical therapy alone in individuals with patellofemoral pain syndrome (PFPS). Read more about this study

Who is it for?
Ages 18 to 45 years
What is being tested?
Standardized Physical Therapy and Standardized Physical Therapy with Clamshell Exercise
Could I receive a placebo?
No, everyone receives an active treatment
How many people
40 participants
Where
1 sitePakistan
Study dates
10 Jan 2026to 10 Jun 2026
Phase
Interventional
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 45 years
  • All sexes
  • No healthy volunteers
  • Adult

Who may be able to join

  • Adults aged 18 to 45 years. Male or female participants. Clinically diagnosed with patellofemoral pain syndrome (PFPS) according to the American Physical Therapy Association (APTA) clinical practice guidelines.
  • Presence of retropatellar or peripatellar pain. Reproduction of retropatellar or peripatellar pain during squatting or other functional activities that load the patellofemoral joint in knee flexion.
  • Symptoms present for at least 3 months. Pain intensity of ≥3 on the Numeric Pain Rating Scale (NPRS) during aggravating activities.
  • Able and willing to provide written informed consent and comply with the study procedures.

Who cannot join

  • History of knee surgery, ligament injury, meniscal tear, patellar dislocation, or knee osteoarthritis.
  • Lumbar radiculopathy, hip pathology, or systemic inflammatory arthritis (e.g., rheumatoid arthritis).
  • Corticosteroid injection or knee surgery within the previous 3 months. Neuromuscular disorders affecting muscle function (e.g., stroke or Parkinson's disease).
  • Pregnancy or within 6 months postpartum. Family history of early degenerative joint disease. Any condition that, in the investigator's opinion, would interfere with safe participation or completion of the study.

Trial locations and contacts

1 site in 1 country.

Pakistan1 site
  • Tahir general Hospital Charsadda

    Charsadda, KPK, 24420

Other trials in Pakistan

About this study

Official title: Effects of Clamshell Exercises in Addition to Standardized Physical Therapy in the Management of Patellofemoral Pain Syndrome. A Randomized Controlled Trial

This randomized controlled trial aims to evaluate whether adding clamshell exercises to standardized physical therapy provides greater improvements in pain and knee function than standardized physical therapy alone in individuals with patellofemoral pain syndrome (PFPS). PFPS is a common musculoskeletal condition characterized by pain around or behind the kneecap that is aggravated by activities such as stair climbing, squatting, running, and prolonged sitting.

Participants aged 18-45 years with clinically diagnosed PFPS will be randomly assigned to one of two groups. The control group will receive standardized physical therapy consisting of warm-up exercises, stretching, quadriceps and lower-limb strengthening exercises, and cool-down activities. The experimental group will receive the same standardized physical therapy program with the addition of clamshell exercises targeting the gluteus medius and hip external rotator muscles.

Both groups will participate in supervised treatment sessions lasting approximately 45 minutes, three times per week, for four weeks. Pain intensity will be measured using the Numeric Pain Rating Scale (NPRS), and knee function will be assessed using the Kujala Anterior Knee Pain Scale before and after the intervention. The findings of this study may help determine whether incorporating clamshell exercises into routine physiotherapy improves rehabilitation outcomes for patients with PFPS.

Read the detailed description

Patellofemoral pain syndrome (PFPS) is one of the most common causes of anterior knee pain, affecting both physically active individuals and the general population. The condition is associated with pain during activities that increase patellofemoral joint loading, including squatting, stair climbing, running, jumping, and prolonged sitting. Altered lower-limb biomechanics, particularly weakness of the hip abductors and external rotators, may contribute to excessive femoral internal rotation and dynamic knee valgus, thereby increasing patellofemoral joint stress.

Conventional physiotherapy for PFPS typically includes stretching, quadriceps strengthening, and functional rehabilitation. Although these interventions are beneficial, many patients continue to experience persistent symptoms or recurrence. Recent evidence suggests that strengthening the hip musculature, particularly the gluteus medius, may improve lower-limb alignment and reduce patellofemoral joint stress. The clamshell exercise is a simple, low-cost exercise designed to activate the hip abductors and external rotators and may provide additional clinical benefit when combined with standard physiotherapy.

The purpose of this randomized controlled trial is to determine whether adding clamshell exercises to standardized physical therapy results in greater reductions in pain and improvements in knee function compared with standardized physical therapy alone in patients with PFPS.

Participants aged 18-45 years who meet the American Physical Therapy Association clinical diagnostic criteria for PFPS and have symptoms lasting at least three months with a pain score of 3 or higher on the Numeric Pain Rating Scale (NPRS) will be recruited. Participants with previous knee surgery, significant ligament or meniscal injuries, patellar dislocation, osteoarthritis, lumbar radiculopathy, hip pathology, systemic inflammatory arthritis, recent corticosteroid injection or surgery, neuromuscular disorders, pregnancy, or other exclusion criteria will not be eligible.

Approximately 40 participants will be enrolled using purposive sampling after accounting for potential loss to follow-up. Participants will be randomly allocated into one of two treatment groups:

Control Group: Standardized physical therapy. Experimental Group: Standardized physical therapy plus clamshell exercises.

Both groups will receive equal treatment duration of approximately 45 minutes per session, three sessions per week for four weeks. Standardized physical therapy includes warm-up activities, stretching of the hamstrings, quadriceps, gastrocnemius-soleus complex, and iliotibial band, quadriceps and lower-limb strengthening exercises, and cool-down stretching. The experimental group will additionally perform side-lying clamshell exercises (3 sets of 12-15 repetitions) during each treatment session.

Outcome assessments will be performed at baseline and after completion of the intervention. Pain intensity will be evaluated using the Numeric Pain Rating Scale (NPRS), while knee function will be assessed using the Kujala Anterior Knee Pain Scale. Statistical analyses will be conducted using SPSS version 27. Appropriate parametric or non-parametric tests will be selected based on data distribution, with statistical significance established at p < 0.05.

Ethical approval will be obtained from the Research Ethics Review Committee of Ibadat International University, Islamabad, and permission will be obtained from Alkhidmat Hospital, Peshawar. Written informed consent will be obtained from all participants before enrollment. Participant confidentiality will be maintained throughout the study, and participation will be voluntary with the right to withdraw at any stage without penalty.

Being tested
Standardized Physical Therapy, Standardized Physical Therapy with Clamshell Exercise
Keywords
Patellofemoral Pain Syndrome (PFPS), Anterior Knee Pain, Clamshell Exercise, Hip Abductor Strengthening
Medical subject headings
Patellofemoral Pain Syndrome

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Standardized Physical TherapyBehavioural

    Also called Conventional Physiotherapy

    Standardized physical therapy consists of warm-up exercises, stretching of the hamstrings, quadriceps, gastrocnemius-soleus, and iliotibial band, quadriceps and lower-limb strengthening exercises (including static quadriceps exercises, straight leg raises, hip strengthening exercises, and mini-squats), followed by cool-down stretching. The control group receives this intervention for approximately 35 minutes per session, three sessions per week for four weeks.

  • Standardized Physical Therapy with Clamshell ExerciseBehavioural

    Also called Side-lying Clamshell Exercise

    Participants perform side-lying clamshell exercises to strengthen the gluteus medius and hip external rotator muscles. The exercise is performed as 3 sets of 12-15 repetitions under physiotherapist supervision. This intervention is added to standardized physical therapy in the experimental group, resulting in a total treatment time of approximately 45 minutes per session, three sessions per week for four weeks.

Study groups in NCT07730437
Study groupRoleWhat they receive
Standardized Physical Therapy (Control)ExperimentalParticipants will receive standardized physical therapy consisting of warm-up exercises, stretching, quadriceps and lower-limb strengthening exercises, and cool-down activities. Each treatment session will last approximately 35 minutes, three times per week for four weeks.
Receives: Behavioral: Standardized Physical Therapy
Standardized Physical Therapy + Clamshell ExercisesExperimentalParticipants will receive standardized physical therapy together with side-lying clamshell exercises targeting the gluteus medius and hip external rotator muscles. Treatment sessions will last approximately 45 minutes, three times per week for four weeks. The only additional intervention compared with the control group is the inclusion of clamshell exercises.
Receives: Behavioral: Standardized Physical Therapy with Clamshell Exercise

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in Pain Intensity Measured by the Numeric Pain Rating Scale (NPRS)

    Pain intensity will be assessed using the 11-point Numeric Pain Rating Scale (NPRS), where 0 indicates no pain and 10 indicates the worst imaginable pain. The primary outcome is the change in NPRS score from baseline to the end of the intervention.

    Measured: Baseline and Week 4 (end of intervention)

Secondary outcomes (1)
  1. Change in Knee Function Measured by the Kujala Anterior Knee Pain Scale

    Knee function will be evaluated using the Kujala Anterior Knee Pain Scale, a validated patient-reported outcome measure assessing symptoms and functional limitations associated with patellofemoral pain syndrome. The secondary outcome is the change in Kujala score from baseline to the end of the intervention.

    Measured: Baseline and Week 4 (end of intervention)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted28 Jul 2026
  2. Study start10 Jan 2026
  3. Primary completion30 May 2026
  4. Study completion10 Jun 2026

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Model description
Participants will be randomly assigned to one of two parallel groups. The control group will receive standardized physical therapy for 35 minutes per session, while the experimental group will receive standardized physical therapy plus clamshell exercises for a total of 45 minutes per session. Both groups will attend supervised treatment sessions three times per week for four weeks. Outcomes will be compared between groups at baseline and after completion of the intervention.
Masking
Single blind
Who is masked
Outcomes assessor
Enrolment
40 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07730437
Sponsor's protocol ID
IIUI/RERC/ADT/2026/O2/229
Status last verified
Jul 2026
First submitted
23 Jul 2026
Last updated
28 Jul 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No: Individual participant data (IPD) collected during this study will not be made publicly available because informed consent for public data sharing was not obtained, and sharing could compromise participant confidentiality. Aggregate study results will be reported in publications and presentations without identifying individual participants.

Publications

  • Neal BS, Lack SD, Lankhorst NE, Raye A, Morrissey D, van Middelkoop M. Risk factors for patellofemoral pain: a systematic review and meta-analysis. Br J Sports Med. 2019;53(5):270-81. 2. Lack S, Barton C, Sohan O, Crossley K, Morrissey D. Proximal muscle rehabilitation is effective for patellofemoral pain: a systematic review with meta-analysis. Br J Sports Med.2015;49(21):1365-76. 3. Rathleff MS, Roos EM, Olesen JL, Rasmussen S. Exercise during school hours when added to patient education improves outcome for 2 years in adolescent patellofemoral pain: a cluster randomised trial. Br J Sports Med. 2015;49(6):406-12. 4. Bolgla LA, Boling MC. An update for the conservative management of patellofemoral pain syndrome: a systematic review of the literature from 2000 to 2010. Int J Sports Phys Ther. 2011;6(2):112-25. 5. Powers CM. The influence of abnormal hip mechanics on knee injury: a biomechanical perspective. J Orthop Sports Phys Ther. 2010;40(2):42-51. 6. Ferber R, Bolgla L, Earl-Boehm JE, Emery C, Hamstra-Wright K. Strengthening of the hip and core versus knee muscles for the treatment of patellofemoral pain: a multicenter randomized controlled trial. J Athl Train. 2015;50(4):366-77. 7. Khayambashi K, Fallah A, Movahedi A, Bagwell J, Powers C. Posterolateral hip muscle strengthening versus quadriceps strengthening for patellofemoral pain: a comparative control trial. Arch Phys Med Rehabil. 2014;95(5):900-7. 8. Santos TR, Oliveira BA, Ocarino JM, Holt KG, Fonseca ST. Effectiveness of hip muscle strengthening in patellofemoral pain syndrome patients: a systematic review. Braz J Phys Ther. 2015;19(3):167-76. 9. Kamel AM, Ghuiba K, Abd Allah DS, Fayaz NA, Abdelkader NA. Effect of adding short foot exercise to hip and knee focused exercises in treatment of patients with patellofemoral pain syndrome: a randomized controlled trial. J Orthop Surg Res. 2024;19(1):207. 10. Alammari A, Spence N, Narayan A, Karnad SD, Ottayil ZC. Effect of hip abductors and lateral rotators' mu

Questions about this trial

What is this clinical trial studying?

A study testing Standardized Physical Therapy and Standardized Physical Therapy with Clamshell Exercise in people with Patellofemoral Pain Syndrome and Anterior Knee Pain, run by Ibadat International University, Islamabad at 1 site in Pakistan.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 28 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Pakistan. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in Pain Intensity Measured by the Numeric Pain Rating Scale (NPRS) (time frame: Baseline and Week 4 (end of intervention)). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07730437, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Jul 2026.

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