Unsatisfactory failure rates following rotator cuff (RC) repair have led orthopaedic surgeons to explore biological augmentation of the healing enthesis. The subacromial bursa (SB) contains abundant connective tissue progenitor cells (CTPs) that may aid in this process. The purpose of the study was to investigate the influence of patient demographics and tear characteristics on the number of colony-forming units (CFUs) and nucleated cell count (NCC) of SB-derived CTPs. In this study, we harvested SB tissue over the supraspinatus tendon and muscle in 19 patients during arthroscopic RC repair. NCC of each sample was analyzed on the day of the procedure. After 14 days, CFUs were evaluated under a microscope. Spearman’s rank correlation coefficient was then used to determine the relationship between CFUs or NCC and patient demographics or tear characteristics. The study found no significant correlation between patient demographics and the number of CFUs or NCC of CTPs derived from the SB (p > 0.05). The study did significantly observe that increased tear size was negatively correlated with the number of CFUs (p < 0.05). These results indicated that increased tear size, but not patient demographics, may influence the viability of CTPs and should be considered when augmenting RCrepairs with SB.

Complex rotator cuff tears provide a significant challenge for treating surgeons, given their high failure rate following repair and the associated morbidity. The purpose of this study is to evaluate the clinical outcomes of patients who underwent biologically enhanced demineralized bone matrix augmentation of rotator cuff repairs. Twenty patients with complex rotator cuff tears underwent arthroscopic rotator cuff repair by a single surgeon with demineralized bone matrix (DBM) augmentation that was biologically enhanced with platelet-rich plasma and concentrated bone marrow aspirate. Post-operative MRI was used to determine surgical success. Patient reported outcome measures and range of motion data were collected pre-operatively and at the final post-operative visit for each patient. Ten patients (50%) with DBM augmentation of their arthroscopic rotator cuff repair were deemed non-failures. The failure group had less improvement of visual analogue pain scale (p = 0.017), Simple Shoulder Test (p = 0.032), Single Assessment Numerical Evaluation (p = 0.006) and abduction (p = 0.046). There was no difference between the groups for change in American Shoulder and Elbow Society score (p = 0.096), Constant-Murley score (p = 0.086), forward elevation (p = 0.191) or external rotation (p = 0.333). The present study found that 50% of patients who underwent biologically enhanced DBM augmentation of their rotator cuff repair demonstrated MRI-determined failure of supraspinatus healing.

The purpose of this study was to investigate proteomic alteration that occurs to whole blood when converted to activated serum (AS) using an autologous thrombin system. This study further sought to evaluate the functional in vitro effect of AS on tenocytes, chondrocytes, subacromial bursal cells, and osteoblasts. The peptide/protein composition of AS was analyzed by liquid chromatography–mass spectrophotometry (LC-MS). The cell lines were treated with AS, and cellular proliferation was quantified 48 h after treatment. Platelet-derived growth factor (PDGF), insulin-like growth factor 1 (IGF-1), vascular endothelial growth factor (VEGF), interleukin-1 beta (IL-1β), and interleukin-1 receptor antagonist (IL-1Ra) were quantified utilizing enzyme-linked immunosorbent assays (ELISAs). LC-MS identified 357 proteins across the AS and whole blood. Fifty-four of the proteins identified had significant differences between the relative protein abundance of the AS samples compared to whole blood. Treatment with AS in all cell lines significantly increased proliferation compared to control cells at 48 h. Increased PDGF, VEGF, and IGF-1 in all cell lines exposed to AS compared to the control (p < 0.05) were observed. These findings suggest that treatment with AS increases in vitro cellular proliferation and the release of growth factors that may play a role in tissue repair.

The purpose of this study is to determine if arthroscopic shavers can effectively collect and process connective tissue progenitor (CTP) cells from subacromial bursal tissue for utilization in rotator cuff repair augmentation. Subacromial bursal tissue was collected and processed using two arthroscopic shavers, Shaver A and Shaver B, in 10 patients undergoing arthroscopic rotator cuff repair. Each shaver was used in a random order for the same patient. Tissue samples underwent testing for cellular proliferation, cellular concentration, number of colony-forming units (CFU), live/dead assay, fluorescence-activated cells sorting (FACS) analysis, cytokine analysis, and growth factor analysis. Shaver A produced more CFUs compared to Shaver B (210.3 vs. 125.9; p < 0.001). At 3 weeks, cells collected via Shaver A had greater cellular proliferation (0.35 vs. 0.51; p < 0.001) as well as more viable cells (214,773 vs. 132,356 cells/gram; p < 0.001). Tissue collected with Shaver B had greater amounts of the cytokines MMP-1 (3741 vs. 5500 pg/mL; p < 0.001), MMP-3 (1131 vs. 1871 pg/mL; p < 0.001), and MMP-13 (179 vs. 401 pg/mL; p < 0.001), while those collected with Shaver A had greater vascular endothelial growth factor (VEGF) (47.8 vs. 9.0 pg/mL; p < 0.05). Arthroscopic shavers are capable of harvesting and processing CTP cells from subacromial bursal tissue. Different shavers may produce different yields of viable CTP cells.