Please assess the completion status of the following clinical trial:

Trial Title: Platelet-rich Plasma (PRP) Injection for Treating Shoulder Subacromial Impingement Syndrome

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: PARALLEL
- Observational Model: None
- Primary Purpose: TREATMENT
- Time Perspective: None
- Masking: SINGLE
- Phase: None
- Number of Arms: 2.0

Eligibility Criteria:
Inclusion Criteria:~* Any adult male or female between 18 and 65 years of age, inclusive, with clinical diagnosis of shoulder subacromial impingement~Exclusion Criteria:~* Age below 18 or above 65 years~* History of prior shoulder injections or surgery~* History of fracture of the acromion, clavicle, scapula, or proximal humerus~* Known allergy to corticosteroids~* Known allergy to lidocaine

- Gender: ALL
- Minimum Age: 18 Years
- Maximum Age: 65 Years
- Healthy Volunteers: f

Study Arms:
- platelet-rich plasma group (Type: EXPERIMENTAL): Autologous platelet-rich plasma subacromial injection
- Methylprednisolone group (Type: ACTIVE_COMPARATOR): Methylprednisolone subacromial injection

Based on this trial design, predict the completion outcome and termination type (if applicable).