Shoulder impingement results from an “inflammation and degeneration of the

anatomical structures in the region of the subacromial space”.

 The subacromial space is defined by the humeral head inferiorly, the anterior edge and under surface of the

anterior third of the acromion, coracoacromial ligament, and the acromioclavicular

joint superiorly. The height of space between acromion and humeral head ranges

from 1.0 to 1.5 cm as seen on radiographs (anteroposterior view).

SIS is believed to originate from extrinsic causes, intrinsic causes, or a combination of

both. Extrinsic causes, which result in compression of the rotator cuff tendons and

surrounding tissues, include anatomical variants of the acromion, a thickened

coracoacromial ligament, subacromial bursitis, or postural abnormalities.

 

Intrinsic causes are associated with degeneration of the rotator cuff tendons and include agerelated

degeneration that may vary in severity according to genetic predisposition, a

deficient vascular supply, a history of intensive work or tobacco. The diagnosis of SIS

is usually based on the patient’s history and on clinical exam such as the impingement

tests.

Painful shoulders pose a substantial socioeconomic burden, accounting for 2.4% of all

primary care consultations in the UK and 4.5 million visits to physicians annually in

the USA. Subacromial pain accounts for up to 70% of all shoulder-pain problems and

can impair the ability to work or do household tasks. The incidence of shoulder

impingement syndrome (SIS) increases as the population ages.

There are 2 types of treatment for SIS: nonsurgical and surgical. The nonsurgical

treatment options that are recommended usually include exercise therapy, subacromial

corticosteroid injection, rest, nonsteroidal anti-inflammatory drugs (NSAIDs),

physical modalities (eg, therapeutic ultrasound, electrotherapy, manual therapy), and

taping.

Surgical treatment involves decompressing the subacromial space by removing the

bone spur and any involved soft tissue arthroscopically, a procedure known as

arthroscopic subacromial decompression. The indications for surgery are persistent

and severe subacromial shoulder pain combined with functional restrictions that are

resistant to conservative measures.

The use of platelet-rich plasma (PRP) as a biological solution for injuries to tendons

of the rotator cuff has achieved popularity over the past several years. PRP is blood

plasma with a high platelet concentration that, once activated, releases various growth

factors involved in the tissue repair process. Early clinical evidence suggests that

PRP improves pain and function outcomes in some tendinopathies compared to

control injection and baseline status. This could be explained by the analgesic effect

of the PRP via the Protease-activated receptors 4 (PAR4) peptides. There is some

evidence demonstrating a positive effect of PRP in tendinopathies and osteoarthritis

of the knee; however, the evidence in rotator cuff tendinopathy is limited.

In spite of increased PRP use in clinical settings, we found only 3 randomized

controlled trials that evaluated the effectiveness of PRP injection in treating rotator

cuff tendinopathy nonsurgically.

In view of advantages of autologous PRP in SIS and reduction of subacromial

impingement by arthroscopic subacromial decompression we plan to study the

evaluation of functional outcome of arthroscopic subacromial decompression and

PRP augmentation in shoulder impingement syndrome.