Outcomes of platelet rich plasma injections in the adhesive capsulitis of the shoulder

Background: Platelet rich plasma (PRP) injections have been utilized in an attempt to provide improved pain and functional outcomes to patients with a variety of orthopaedic ailments. Adhesive capsulitis, also known as frozen shoulder is a common debilitating condition that carries significant morbidity due to the painful and prolonged course. Various studies have investigated intra-articular PRP administration with different methodologies and outcomes. Hypothesis/purpose: We sought to perform a meta-analysis on outcomes of adhesive capsulitis after PRP injection, determine effectiveness compared to corticosteroid, and compare adverse events. Study design: Meta analysis. Methods: EMBASE, EBSCO, Pubmed and Google Scholar were used to extract titles and abstracts using keywords "adhesive capsulitis", "frozen shoulder", "PRP", "platelet rich plasma". 41 articles were found and after duplicates removed and full-text review, 7 studies investigating 385 patients undergoing PRP or corticosteroid in-jections were found. Age, gender, body mass index (BMI), and ASA scores were obtained. Patient reported outcomes (PROs) were obtained and all reported range of motion (ROM) were recorded and compared after PRP and steroid injections using random effects meta-regression pre-injection and post-injection. Results: Both intra-articular PRP and steroid injections resulted in improved outcomes for treatment of adhesive capsulitis at 3 months. PRP injections had significantly better range of motion in passive forward flexion (151 degrees vs 144.1 degrees, p = 0.024) and had improved Shoulder Pain and Disability Index (SPADI) scores (14.6 degrees vs 18.6 degrees, p = 0.009) compared to steroid, however these may not reach minimum clinical thresholds. PRP had significantly better active (60 degrees vs 43. 5 degrees, p = 0.038) and passive internal rotation (69.6 degrees vs 52.7 degrees, p = 0.017) compared to steroid which did reach minimum clinical thresholds. There were no differences detected between VAS pain, active forward flexion, extension, abduction, external rotation nor difference in adverse events. Discussion: Both injections decreased pain and improved range of motion in patients. Intra-articular PRP injections may result in improved internal rotation compared to corticosteroid. Improvement in SPADI and passive forward flexion may be statistically significantly but may not be clinically relevant. Level of evidence: 3, Therapeutic.