The purpose of this study is to compare the effectiveness of arthroscopic subacromial decompression (acromioplasty) to arthroscopic subacromial bursectomy (no acromioplasty) in rotator cuff impingement syndrome. The investigators' hypothesis is that arthroscopic subacromial decompression provides no additional benefit, as evaluated with disease specific quality of life measures, compared to arthroscopic bursectomy.

The most commonly performed surgical procedure to treat rotator cuff tendinosis, when no full-thickness tear exists, is subacromial decompression (acromioplasty). This procedure is based on the theory that primary acromial morphology, (an extrinsic cause), is the initiating factor leading to the dysfunction and eventual tearing of the rotator cuff.

Subacromial decompression involves surgical excision of the subacromial bursa, resection of the coracoacromial ligament, resection of the anteroinferior portion of the acromion, and resection of any osteophytes from the acromioclavicular joint that are thought to be contributing to impingement.

Several studies have indicated that the vast majority of partial-thickness tears are found on the articular surface of the rotator cuff which is not in keeping with the theory that rotator cuff impingement is primarily a result of acromion morphology.

Burkhart proposed that pathologic changes in the supraspinatus tendon occur primarily as a result of overuse and tension overload (an intrinsic factor), resulting in superior migration of the humeral head during active elevation.

Budoff et al., suggest that since the coracoacromial ligament stabilizes the rotator cuff to prevent uncontrolled superior migration of the humeral head, resection of the coracoacromial ligament during arthroscopic subacromial decompression may cause, in the long-term, additional proximal migration of the humeral head.

Arthroscopic bursectomy with debridement of rotator cuff tears alone, without acromioplasty, addresses the primary anatomical pathology and may offer similar success rates to subacromial decompression, without the risk of future instability caused by resection of the acromion and coracoacromial ligament.

Inclusion Criteria:

1. Diagnosis of stage II rotator cuff impingement syndrome defined as:

   • Pain referred to the anterior, lateral, or superior shoulder
   • Pain exacerbated by overhead and reaching activities
   • Positive Neer and/or Hawkins impingement signs

2. Failure of 6 months of conservative treatment. Failed conservative treatment will be defined as persistent pain and disability despite adequate non-operative management for 6 months. Non-operative management will be defined as:

   • Modification of activities
   • The use of analgesic and/or anti-inflammatory medication
   • Physiotherapy: Physiotherapy must have included the goal of regaining full range of motion, working towards normal kinematics through increased strength of the rotator cuff muscles. Patients should have obtained range of motion to 80% of the opposite shoulder (assuming this is normal) for each of: internal rotation, external rotation, and forward elevation. A physiotherapy program that involved massage, ultrasound, and/or heat only would not be considered adequate treatment for this study.

3. Patients willing to be followed on a regular basis

4. Patients 18 years of age and older

Exclusion Criteria:

1. Clinical evidence or history of major joint trauma, infection, surgery, glenohumeral arthritis, or instability.
2. Clinical evidence of internal impingement.
3. Patients with full-thickness rotator cuff tear as documented on advanced imaging or during surgery.
4. Patients with bursal surface tears as documented on advanced imaging or during surgery.
5. Patients who are found during surgery to have a partial-thickness tear greater than 50% of tendon thickness.
6. Patients with evidence of a lateral down sloping acromion.
7. Patients unfit for surgery
8. Patients unable to provide informed consent or adequately participate in this study due to a language barrier or psychiatric illness.
9. Patients with a major medical illness whose condition or treatment would affect their quality of life and, as such, affect the results of this study.