Shoulder pain is one of the most common musculoskeletal complaints and its prevalence varies
between 7-26%. Although some of the patients with shoulder pain show complete recovery, pain
persists in some of them. One of the most common sources of pain in these patients is
subacromial impingement syndrome (SIS) leading to rotator cuff pathology. The multifactorial
nature of pain in these patients makes the treatment of SIS difficult.
Central sensitization (CS) has been reported as one of the factors associated with
persistence of pain in patients with shoulder pain in different etiologies, especially in the
SIS. CS can be summarized as an increase in the response of neurons located in the central
nervous system to subthreshold stimuli and is the source of chronic pain in many diseases. A
decrease in the pressure pain threshold was observed in the painful shoulder of 58 patients
with experimental pain response in the shoulder.
In a meta-analysis of patients with shoulder pain, a decrease in pressure pain threshold was
found in 29-77% of patients, while SS was found in 11-24% of patients. The authors emphasized
the significant correlation of CS with poor treatment response. There is increasing evidence
that CS negatively affects various pain treatment responses, including surgery. Considering
the frequency of CS in patients with shoulder pain, it is likely to have a negative impact on
treatment response in these patients as well. One of the most common treatments for SIS is
subacromial/ intra-articular shoulder injection. Although several factors have been
identified in the prediction of shoulder injection outcomes, the effect of pain sensitization
on these procedures is not yet known.
This study was designed as a prospective single-center study. Patients aged 18-65 years with
rotator cuff lesions lasting more than three months and presenting to our physical medicine
and rehabilitation outpatient clinic will be included. Patients who have received medical
treatment as part of routine practice and have not had an adequate response will be evaluated
before and after injection. Injection preference will be determined according to the patient
primary complaint and lesion and will be administered into the subacromial space or into the
shoulder joint. There is no additional interventional procedure due to the study. Patients
will be divided into 2 groups with and without central sensitization. A total of 18 patients
were planned for each group. The study will be conducted between March 2023 and June 2024.
Within the scope of the study, age, gender, body mass index, marital status, education level
and occupation of the participants will be recorded as demographic data. Clinical evaluation
includes pain duration, treatments received, pain intensity (numeric pain scale 0-10),
disease-related MRI/USG findings and the following evaluations.
All patients will be evaluated before injection, 1 week, 1 and 3 months after injection.
Within the scope of evaluation, Central Sensitization Scale, Quick DASH, SF-36 and Hospital
Anxiety and Depression questionnaire, pressure pain threshold, goniometric shoulder range of
motion measurement, hand grip strength (with Jamar hydraulic hand dynamometer), numeric pain
scale (no pain: 0- unbearable pain: 10) and pain intensity will be recorded at each visit.
Data analysis will be performed by using the Statistical Package for the Social Sciences
(SPSS, version 23.0, IBM Corp., Armonk, NY, USA).