Shoulder Dislocation Case Study

Patients

This is a case-control study (level 3 of evidence). We evaluated 29 outpatients with traumatic anterior shoulder dislocation from XXXXXXXXXXXXX of XXXXXXXX (XXXXXX), Brazil. After the first episode of shoulder dislocation, patients were treated for at least 2 weeks with shoulder immobilization. All patients underwent arthroscopic surgical treatment for shoulder instability. The inclusion criteria were as follows: no history of previous surgery for an injured shoulder, positive apprehension test and a Bankart lesion on magnetic resonance imaging. The exclusion criteria were as follows: presence of significant bone defects (humeral and/or glenoid greater than 20%), presence of clinical signs of posterior or multidirectional instability

All patients signed an informed consent before data and sample collection. All patients answered a preoperative questionnaire that included questions regarding gender, age at surgery, age of onset, duration of symptoms, number of luxation episodes, type of work, physical activity and other clinical variables. In our sample, physical activity involving the upper limbs included swimming, tennis, basketball, handball, climbing and the some martial arts (judo, jiu-jitsu and capoeira, a Brazilian martial art).

Tissue samples

During the arthroscopic procedure, tissue samples were obtained from AI, AS and P sites of the glenohumeral capsule of each patient. To minimize the variation of sampling, the tissue specimens were taken by two of the authors (XXXXX and XXXX). The tissue samples were collected as previously described.11, 12

All tissue specimens were immediately immersed in RNAlater® solution (Qiagen, Germany) and then stored at -20 °C until RNA extraction.

RNA

qPCR were performed with 80-100 ng of cDNA input using TaqMan Low-Density Array (TLDA) cards (Life Technologies, USA) and ViiA 7 Real-Time PCR System (Life Technologies, USA). Only inventoried TaqMan Gene Expression Assays (Life Technologies, USA) were used for gene expression analysis.

The HPRT1 and B2M genes were used as internal controls to normalize the sample input amount.24 All qRT-PCR reactions were performed in triplicate for all target genes (COMP: Hs00164359_m1; FN1: Hs00365052_m1; TNC: Hs01115665_m1; TNXB: Hs00372889_g1) and reference genes (HPRT1: Hs02800695_m1; B2M: Hs00984230_m1). To exclude technical variations, the target and reference genes were assayed on the same card.

The cycle relative threshold method (Crt method) was applied. The expression of target genes across the samples was calculated using the equation ΔCrt, in which [ΔCrt = target gene Crt – the mean of reference genes Crt]. A lower ΔCrt indicates higher gene