UHMWPE suture induced pseudotumor following arthroscopic rotator cuff repair: A case report

UHMWPE suture shows excellent biocompatibility and complication associated with suture debris had not been described before in shoulder surgery. In this study, a case of a 38-year-old man with a wear debris pseudotumor mimicking osteochondromatosis in the subacromial bursa five years after arthroscopic rotator cuff repair using a composite braid suture (a polydioxanone core with a sleeve of UHMWPE) was presented. Histological examination confirmed the presence of suture fragments surrounded with the osteochondral layer without inflammatory reactions. The present study implies the potential risk of free fragmented remnants from the UHMWPE suture. Because of the silent nature of the histological response, a high index of suspicion should be necessary to disclose the chanciness of its use.

Histological and molecular features of the subacromial bursa of rotator cuff tears compared to non-tendon defects: a pilot study

Background The role of the subacromial bursa in the development or healing of shoulder pathologies is unclear. Due to this limited knowledge, we aimed to understand specific reactions of the subacromial bursa according to rotator cuff (RC) pathologies compared to non-tendon defects of the shoulder. We hypothesized that the tissue composition and inflammatory status of the bursa are likely to vary between shoulder pathologies depending on the presence and the extent of RC lesion. Method Bursa samples from patients with either 1) shoulder instability with intact RC (healthy bursa, control), 2) osteochondral pathology with intact RC, 3) partial supraspinatus (SSP) tendon tear, or 4) full-thickness SSP tear were investigated histologically and on gene expression level. Result Bursae from SSP tears differed from non-tendon pathologies by exhibiting increased chondral metaplasia and TGFβ1 expression. MMP1 was not expressed in healthy bursa controls, but strongly increased with full-thickness SSP tears. Additionally, the expression of the inflammatory mediators IL1β, IL6, and COX2 increased with the extent of SSP tear as shown by correlation analysis. In contrast, increased angiogenesis and nerve fibers as well as significantly upregulated IL6 and COX2 expression were features of bursae from patients with osteochondral pathology. Using immunohistochemistry, CD45+ leukocytes were observed in all examined groups, which were identified in particular as CD68+ monocytes/macrophages. Conclusion In summary, besides the strong increase in MMP1 expression with SSP tear, molecular changes were minor between the investigated groups. However, expression of pro-inflammatory cytokines correlated with the severity of the SSP tear. Most pronounced tissue alterations occurred for the osteochondral pathology and full-thickness SSP tear group, which demonstrates that the bursal reaction is not exclusively dependent on the occurrence of an SSP tear rather than longstanding degenerative changes. The present bursa characterization contributes to the understanding of specific tissue alterations related to RC tears or non-tendon shoulder pathologies. This pilot study provides the basis for future studies elucidating the role of the subacromial bursa in the development or healing of shoulder pathologies.

Bursa-Derived Cells Show a Distinct Mechano-Response to Physiological and Pathological Loading in vitro

The mechano-response of highly loaded tissues such as bones or tendons is well investigated, but knowledge regarding the mechano-responsiveness of adjacent tissues such as the subacromial bursa is missing. For a better understanding of the physiological role of the bursa as a friction-reducing structure in the joint, the study aimed to analyze whether and how bursa-derived cells respond to physiological and pathological mechanical loading. This might help to overcome some of the controversies in the field regarding the role of the bursa in the development and healing of shoulder pathologies. Cells of six donors seeded on collagen-coated silicon dishes were stimulated over 3 days for 1 or 4 h with 1, 5, or 10% strain. Orientation of the actin cytoskeleton, YAP nuclear translocation, and activation of non-muscle myosin II (NMM-II) were evaluated for 4 h stimulations to get a deeper insight into mechano-transduction processes. To investigate the potential of bursa-derived cells to adapt their matrix formation and remodeling according to mechanical loading, outcome measures included cell viability, gene expression of extracellular matrix and remodeling markers, and protein secretions. The orientation angle of the actin cytoskeleton increased toward a more perpendicular direction with increased loading and lowest variations for the 5% loading group. With 10% tension load, cells were visibly stressed, indicated by loss in actin density and slightly reduced cell viability. A significantly increased YAP nuclear translocation occurred for the 1% loading group with a similar trend for the 5% group. NMM-II activation was weak for all stimulation conditions. On the gene expression level, only the expression of TIMP2 was down-regulated in the 1 h group compared to control. On the protein level, collagen type I and MMP2 increased with higher/longer straining, respectively, whereas TIMP1 secretion was reduced, resulting in an MMP/TIMP imbalance. In conclusion, this study documents for the first time a clear mechano-responsiveness in bursa-derived cells with activation of mechano-transduction pathways and thus hint to a physiological function of mechanical loading in bursa-derived cells. This study represents the basis for further investigations, which might lead to improved treatment options of subacromial bursa-related pathologies in the future.

Factors Associated With Clinical Improvement and the Disappearance of Calcifications After Ultrasound-Guided Percutaneous Lavage of Rotator Cuff Calcific Tendinopathy: A Post Hoc Analysis of a Randomized Controlled Trial

Background: Calcific tendinitis of the rotator cuff is a frequent cause of shoulder pain. Ultrasound-guided percutaneous lavage (UGPL) is an effective treatment, but factors associated with good clinical and radiological outcomes still need to be identified. Purpose: To study the clinical, procedural, and radiological characteristics associated with improved shoulder function and the disappearance of calcification on radiograph after UGPL. Study Design: Case-control study; Level of evidence, 3. Methods: This is a post hoc analysis of the CALCECHO trial, a double-blinded randomized controlled trial conducted on 132 patients. The trial assessed the effect of corticosteroid injections after UGPL, and patients were randomly assigned to receive either corticosteroid or saline solution in the subacromial bursa. We analyzed all patients included in the randomized controlled trial as 1 cohort. We collected the patients’ clinical, procedural, and radiological characteristics at baseline and during follow-up (3, 6, and 12 months). Univariable analysis, followed by multivariable stepwise regression through forward elimination, was performed to identify the factors associated with clinical success (Disabilities of the Arm, Shoulder and Hand [DASH] score <15) or the disappearance of calcification. Results: Good clinical outcomes at 3 months were associated with steroid injections after the procedure (odd ratio [OR], 3.143; 95% CI, 1.105-8.94). At 6 months, good clinical evolution was associated with a lower DASH score at 3 months (OR, 0.92; 95% CI, 0.890-0.956) and calcium extraction (OR, 10.7; 95% CI, 1.791-63.927). A lower DASH at 6 months was also associated with a long-term favorable outcome at 12 months (OR, 0.939; 95% CI, 0.912-0.966). Disappearance of calcification at 3 and 12 months occurred more frequently in patients in whom communication was created between the calcification and the subacromial bursa during the procedure (OR, 2.728 [95% CI, 1.194-6.234] at 3 months; OR, 9.835 [95% CI, 1.977-48.931] at 12 months). Importantly, an association between calcification resorption and good clinical outcome was found at each time point. Conclusion: Assessing patients at 3 months seems to be an essential part of their management strategy. Calcium extraction and creating a communication between the calcific deposits and subacromial bursa are procedural characteristics associated with good clinical and radiological evolution.