An observational study in Shoulder Impingement Syndrome, Rotator Cuff Injuries and Pectoralis Minor Tightness, sponsored by Gazi University. Recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 55 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-04.
Sponsored by Gazi University · Observational
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 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.
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):
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
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.
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.
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.
İndividuals aged 18-55 years with no evidence of rotator cuff or other shoulder pathology on magnetic resonance imaging. Propensity score matched 1:1 with the case group on age, sex, BMI, and dominant side.
Pectoralis minor muscle length difference between case and control groups
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.
Time frame: Preoperative assessment, Day 0
Case group
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.
Time frame: Intraoperative, Day 0 (index arthroscopy)
Forward shoulder posture
Anterior displacement of the acromion relative to the thorax measured with a square ruler (standardized upright position). Three trials; mean used.
Time frame: Preoperative assessment, Day 0
Medial Scapular Border Thoracic Distance
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.
Time frame: Preoperative assessment, Day 0
Thoracic Kyphosis and Proximal Kyphosis(Cobb angle)
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.
Time frame: Preoperative imaging review, Day 0
Scapular index (Coracoid-Sternum/Acromian lateral tip - thoracic spine)
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.
Time frame: Preoperative assessment, Day 0
Acromial Morphology
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).
Time frame: Preoperative imaging review, Day 0
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Shoulder Impingement Syndrome→
Gazi University