The Role of Pectoralis Minor Tightness in the Development of Rotator Cuff Tears (PMinor-Rotator)

June 20, 2026 updated by: Cagatay Delice, Gazi University

The Role of Pectoralis Minor Muscle Tightness in the Development of Rotator Cuff Tears: A Propensity Score Matched Case-Control Study

This study investigates whether tightness of a small chest muscle called the pectoralis minor is associated with the development of partial rotator cuff tears in the shoulder. Using a propensity score matched case-control design, the study compares patients with rotator cuff tears (case group, n=45) to patients with intact rotator cuffs (control group, n=45).

Adults aged 18-55 with shoulder pain who are evaluated by MRI and/or shoulder arthroscopy at Gazi University Hospital may be invited. The case group includes patients found to have partial rotator cuff tears during arthroscopy. The control group includes patients whose rotator cuff was documented as intact by MRI. Groups are matched 1:1 on age, sex, BMI, and dominant side.

Before surgery, two trained clinician measures shoulder posture and pectoralis minor length using simple external tools (a digital caliper and ruler-like square). For arthroscopy patients, the surgeon records general arthroscopic findings. No extra procedures are added for research.

We expect to include 90 participants total. The primary hypothesis is that pectoralis minor tightness is more prevalent in patients with rotator cuff tears compared to controls. A secondary hypothesis is that tears in patients with pectoralis minor tightness more often partial-thickness bursal side rotator cuff tear. Results may help clinicians understand shoulder mechanics and improve prevention or rehabilitation strategies.

Study Overview

Status

Recruiting

Conditions

Detailed Description

Rationale and Objectives Pectoralis minor (PM) tightness alters scapular position (anterior tilt, internal rotation) and may increase subacromial compression. This propensity score matched case-control study evaluates whether PM tightness is associated with the development of partial rotator cuff tears (RCTs).

Design and Setting Single-center, propensity score matched case-control study at a tertiary academic hospital (orthopaedic shoulder service, Gazi University Hospital). Care is not altered by participation. All surgical and imaging procedures are standard of care; research procedures are limited to noninvasive postural/PM length measurements and structured data collection.

Participants Inclusion criteria consisted of patients aged 18-55 years who were scheduled to undergo surgical treatment for a partial-thickness rotator cuff tear (case group) and individuals aged 18-55 years with no evidence of rotator cuff or other shoulder pathology on magnetic resonance imaging (control group). Patients were excluded if they had a history of trauma, thoracic outlet syndrome, systemic inflammatory disease, prior surgery on the affected shoulder, and declined participation in the examination. After application of the eligibility criteria, patients with partial-thickness rotator cuff tears will be matched in a 1:1 ratio with patients without rotator cuff or other shoulder pathology. Matching was performed based on age, sex, body mass index (BMI), and dominant extremity involvement. Covariate balance was assessed using absolute standardized differences, with a predefined threshold of 0.1.

Study Procedures

Preoperative assessments (same-day or pre-op clinic):

  • Pectoralis minor length (mm): Pectoralis minor length was measured using a digital caliper, with the coracoid process and the fourth rib adjacent to the sternum serving as palpable anatomical landmarks; three trials recorded; mean used for analysis.
  • Medial scapular border-thoracic distance (mm) using rulers.
  • Forward shoulder posture using a 300 mm square.
  • Imaging abstraction: Standard shoulder radiographs and MRI summarized.
  • Anatomical and radiological measurements were assessed by two independent authors blinded to patient's group status.

Intraoperative assessment (for arthroscopy patients):

Surgeons document tear characteristics using a standardized form based on video visualization.

Sample Size and Power A priori power analysis was performed using effect sizes derived from PMI measurements in previous studies (Cohen's d = 0.91-1.83).Using the smallest effect size as a conservative estimate, a minimum sample size of 20 patients per group was required to achieve 80% power at a two-sided α level of 0.05.

Statistical Analysis Plan

  • Software: IBM SPSS Statistics-26, R (MatchIt package)
  • Normality: Shapiro-Wilk test
  • Comparisons: Paired t-test / Wilcoxon / McNemar for matched pairs
  • Primary outcome: Presence of rotator cuff tear (case vs control) as a function of PM tightness
  • Secondary outcome: The tear is a partial bursal surface tear as a function of PM tightness in the case group
  • Significance level: two-sided alpha=0.05

Study Type

Observational

Enrollment (Estimated)

90

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Turkey (Türkiye)
    • Cankaya
      • Ankara, Cankaya, Turkey (Türkiye), 06500
        • Recruiting
        • Gazi University Hospital
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Inclusion criteria consisted of patients aged 18-55 years who were scheduled to undergo surgical treatment for a partial-thickness rotator cuff tear (case group) and individuals aged 18-55 years with no evidence of rotator cuff or other shoulder pathology on magnetic resonance imaging (control group). Patients were excluded if they had a history of trauma, thoracic outlet syndrome, systemic inflammatory disease, prior surgery on the affected shoulder, and declined participation in the examination.

Description

Inclusion criteria consisted of patients aged 18-55 years who were scheduled to undergo surgical treatment for a partial-thickness rotator cuff tear (case group) and individuals aged 18-55 years with no evidence of rotator cuff or other shoulder pathology on magnetic resonance imaging (control group). Patients were excluded if they had a history of trauma, thoracic outlet syndrome, systemic inflammatory disease, prior surgery on the affected shoulder, and declined participation in the examination.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Rotator Cuff Tear (Case)
Patients who underwent shoulder arthroscopy and were found to have partial rotator cuff tears during surgery. Pectoralis minor length, medial scapular distance, and forward shoulder posture were measured preoperatively. Propensity score matched 1:1 with the control group on age, sex, BMI, and dominant side.
Intact Rotator Cuff (Control)
Patients presenting with shoulder pain whose rotator cuff was documented as intact by MRI findings. Propensity score matched 1:1 with the case group on age, sex, BMI, and dominant side.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pectoralis minor muscle length difference between case and control groups
Time Frame: Preoperative assessment, Day 0
Comparison of pectoralis minor (PM) muscle length (mm) and pectoralis minor index between patients with partial rotator cuff tears (case group) and patients with intact rotator cuffs (control group). PM length is measured as the linear distance from coracoid tip to rib attachment using a digital caliper. The pectoralis minor index was calculated by dividing the pectoralis minor length by the patient's height and multiplying the result by 100.
Preoperative assessment, Day 0

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Forward shoulder posture
Time Frame: Preoperative assessment, Day 0
Anterior displacement of the acromion relative to the thorax measured with a square ruler (standardized upright position). Three trials; mean used.
Preoperative assessment, Day 0
Case group
Time Frame: Intraoperative, Day 0 (index arthroscopy)
Arthroscopic classification of the partial rotator cuff tear appears to begin, recorded with a standardized intraoperative checklist in the case group only. Analysis evaluates whether PM-tight patients more frequently exhibit partial bursal side tear compared to non-tight patients within the RCT group.
Intraoperative, Day 0 (index arthroscopy)
Medial Scapular Border Thoracic Distance
Time Frame: Preoperative assessment, Day 0
Medial scapular distance was measured as the shortest distance between the medial scapular border and the posterior chest wall using a ruler positioned perpendicular to the midpoint of the medial scapular border; three trials, mean used.
Preoperative assessment, Day 0
Thoracic Kyphosis and Proximal Kyphosis(Cobb angle)
Time Frame: Preoperative imaging review, Day 0
Lateral thoracic radiograph measured using the Cobb method: superior endplate line of T5 and inferior endplate line of T12 (use closest visible end vertebrae if either is obscured). Lines perpendicular to each endplate are drawn; the included angle is recorded as the thoracic kyphosis Cobb angle. Proximal thoracic kyphosis is also measured between T2 and T5.
Preoperative imaging review, Day 0
Scapular index (Coracoid-Sternum/Acromian lateral tip - thoracic spine)
Time Frame: Preoperative assessment, Day 0
The scapular index was determined using a digital caliper by measuring the distance between the midpoint of the sternal notch and the medial aspect of the coracoid process, as well as the horizontal distance between the posterolateral angle of the acromion and the thoracic spine, and was calculated as (sternal notch-coracoid distance / acromion-thoracic spine distance) × 100.
Preoperative assessment, Day 0
Acromial Morphology
Time Frame: Preoperative imaging review, Day 0
Acromial morphology was assessed on supraspinatus outlet radiographs according to the Bigliani classification and categorized as type I (flat), type II (curved), or type III (hooked).
Preoperative imaging review, Day 0

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Gazi University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 18, 2025

Primary Completion (Estimated)

June 25, 2026

Study Completion (Estimated)

June 30, 2026

Study Registration Dates

First Submitted

November 13, 2025

First Submitted That Met QC Criteria

November 13, 2025

First Posted (Actual)

November 14, 2025

Study Record Updates

Last Update Posted (Actual)

June 25, 2026

Last Update Submitted That Met QC Criteria

June 20, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • E-77082166-302.08.01-1273486

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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