Validation of the Western Ontario Rotator Cuff Index in Patients With Arthroscopic Rotator Cuff Repair (WORC)

• Criterion validity of the WORC [ Time Frame: 6 months ] [ Designated as safety issue: No ]
  Criterion validity is measured by comparing WORC with a general quality of life questionnaire (SF-36) and a commonly used clinical shoulder score (Constant Score) both at T0 and T1. Bland Altman plots will be used to estimate 95% boundaries of concurrence.
• Responsiveness of the WORC [ Time Frame: 6 months ] [ Designated as safety issue: No ]
  Responsiveness will be determined by calculating the standardized response means and effect sizes on T0 and T2 scores on WORC, SF-36 and Constant scores for the subgroups.
• Differentiation between patient groups [ Time Frame: 6 months ] [ Designated as safety issue: No ]
  A comparison of WORC scores between the three distinct groups is made, to see whether WORC scores can differentiate between them. WORC scores will be compared with SF-36 to investigate whether the noted differences correlate with notable clinical differences and can be expressed as MCID's (minimal clinical important differences).

Arthroscopic rotator cuff repair is described as being a successful procedure. These results are often derived from clinical general shoulder examinations, which are then classified as 'excellent', 'good', 'fair' or 'poor'. However, the cut-off points for these classifications vary and sometimes modified scores are used.

Arthroscopic rotator cuff repair is performed to improve quality of life. Therefore, disease specific health-related quality of life patient-administered questionnaires are needed. The WORC is a quality of life questionnaire designed for patients with disorders of the rotator cuff. The score is validated for rotator cuff disease, but not for rotator cuff repair specifically.

The aim of this study is to investigate reliability, validity and responsiveness of WORC in patients undergoing arthroscopic rotator cuff repair.

An approved translation of the WORC into Dutch is used. In this prospective study three groups of patients are used: 1.Arthroscopic rotator cuff repair; 2.Disorders of the rotator cuff without rupture; 3.Shoulder instability.

The WORC, SF-36 and the Constant Score are obtained twice before therapy is started to measure reliability and validity. Responsiveness is tested by obtaining the same tests after therapy.

1. Patients undergoing arthroscopic rotator cuff repair. These patients have a clinical suspicion of a symptomatic rotator cuff tear and a partial or full thickness lesion seen on MRI or Ultrasound and confirmed during the arthroscopic repair procedure.
2. Patients diagnosed as having non-Ruptured DRC. They have a clinical suspicion of DRC and no rupture of the rotator cuff on MRI or Ultrasound.
3. Patients will be diagnosed with shoulder instability

• Rotator Cuff Lesion
• Disorder of Rotator Cuff
• Other Instability, Shoulder

• Rotator cuff repair group
  Patients undergoing an arthroscopic rotator cuff repair
• DRC without rupture
  Disorders of the rotator cuff without rupture
• Shoulder instability
  Shoulder instability

Inclusion Criteria:

• 18 years or older
• written informed consent
• diagnosis for group 1, 2 or 3

Exclusion Criteria:

• lack of understanding the Dutch language
• not able to complete questionnaires independently
• additional shoulder pathology like adhesive capsulitis, AC-pathology and osteoarthritis
• previous shoulder surgery