Unexpected positive cultures of humeral head detected with dithiothreitol in primary shoulder arthroplasty.

BACKGROUND: Unexpected positive cultures (UPCs) are frequently observed in primary shoulder arthroplasty, and its clinical significance has not yet been well defined. This study aimed to evaluate the UPCs in humeral head in primary shoulder replacement and to understand if UPCs increase in patients with risk factors for contamination (previous surgery or infiltrations). METHODS: Patients undergoing total shoulder replacement were enrolled in this prospective observational study. To reduce the risk of humeral head contamination, all known procedures to reduce Cutibacterium acnes burden of the skin were implemented. Patients were divided into 2 groups, namely, patients who had undergone previous rotator cuff repair or infiltration and patients with no risk factors for contamination. All the humeral heads harvested were treated with dl-dithiothreitol, in a specific device (MicroDTTect), to increase the sensitivity of the cultures for bacterial identification. The cultures were analyzed for aerobic and anaerobic bacteria for up to 14 days. RESULTS: The UPCs' positivity rate of the 80 patients in the study was 19% (15 patients). The positivity rates for UPCs in the group with and without risk factors were 30% (12 patients) and 7.5% (3 patients), respectively. The rate of positive culture was higher in men (87%) than in women (13%). The observed positivity was due to C acnes and Peptoniphilus asaccharolyticus, both slow-growing anaerobes. CONCLUSIONS: Patients with previous surgery or infiltrations had a 4-fold higher rate of positivity for UPCs compared with patients without previous risk factors. The higher percentage of positivity in patients with risk factors could be related to changes in the joint microenvironment after shoulder procedures. We do not know whether the presence of UPCs could be associated with the development of periprosthetic infections at longer follow-up.

Clinical and radiological outcome after arthroscopic rotator cuff repair using PEEK-CF anchors.

PURPOSE: The goal of this study was to evaluate the clinical and radiological outcome after arthroscopic rotator cuff repair using new carbonfiber reinforced polyetheretherketone (CF-PEEK) suture anchors. METHODS: One hundred (n=100) patients with rotator cuff tears were enrolled at seven French hospitals between July 2019 and June 2020. Pain levels, Constant score and Subjective Shoulder Value (SSV) were taken preoperatively and 6months postoperatively. Ultrasonography (US) was performed at 6months postoperatively to evaluate tendon healing using the Sugaya classification. Statistical analysis was done with the Student t-test with 95% confidence intervals. RESULTS: One hundred patients of the 100 patients were followed at 6months. The mean SSV and Constant score improved from 40.1% preoperatively to 78% at 6months (p<0.0001) and from 43 points preoperatively to 65 points at 6months (p<0.0001), respectively. The mean level of pain, as measured with the visual analogue scale, decreased from 5.9 to 1.6 (p<0.001). There were no postoperative complications that resulted in revision surgery. CONCLUSION: The study showed good results at 6months follow-up using carbonfiber reinforced PEEK anchors with improved Constant and SSV scores as well as a high ultrasonographic tendon healing rate, making PEEK-CF anchors safe to use, comparable to commonly used anchors. LEVEL OF EVIDENCE: IV.

Vancomycin powder embedded in collagen sponge decreases the rate of prosthetic shoulder infection.

BACKGROUND: Shoulder arthroplasty is a successful procedure to treat degenerative and traumatic diseases of the glenohumeral joint. Periprosthetic infection represents an infrequent but dreaded complication (2%-4%). Application of intrawound vancomycin powder seems to reduce periprosthetic infections, but limited information is available on its efficiency in shoulder arthroplasty. The purpose of this study was to evaluate if the vancomycin powder embedded in a collagen sponge could decrease the rate of prosthetic shoulder infection. METHODS: A retrospective analysis of 827 patients undergoing total shoulder arthroplasty was performed. The study involved a control group of 405 patients and a group of 422 with the intraoperative insertion of intrawound vancomycin powder. Incidence of periprosthetic infection was evaluated comparing the 2 groups at a minimum follow-up of 12 months. Patient demographics, comorbidities, and perioperative information were compared between the 2 groups. RESULTS: No infection was observed in the group treated with intrawound vancomycin, and 13 cases of infection were observed in the control group (3.2%) (P value <.001) without subacromial vancomycin application. No wound complications requiring revision were observed as a result of intrawound vancomycin application. DISCUSSION AND CONCLUSION: Intrawound vancomycin powder significantly reduces the rate of periprosthetic shoulder infections without any increase in local and systemic aseptic complications at a minimum follow-up of 12 months. Our results support the use of intrawound local vancomycin for prophylaxis of shoulder periprosthetic infections.

Reliability of open architecture anchors in biocomposite material: medium term clinical and MRI evaluation. Our experience.

OBJECTIVES: Comparing radiologic bone ingrowth and the clinical outcomes of an open-construct (PEEK) (polyether ether ketone) suture anchor with those of a bio-composite suture anchor (glycolic polylactic acid anchors, beta-tricalcium phosphate and calcium sulphate) in patients with arthroscopic rotator cuff repair. METHODS: From August 2017 to January 2019, 33 patients of both sexes, aged between 44 and 78 years underwent arthroscopic rotator cuff repair for tears considered repairable with an extension not exceeding4 cm. The bioabsorbable anchors used comprised glycolic polylactic acid/beta-tricalcium phosphate/ calcium sulphate, and the non-absorbable anchors in polyetheretherketone (PEEK). All patients underwent MRI evaluation at 12 months postoperatively to determine complications and identify any re-tear. RESULTS: Clinical scores showed an improvement from both clinical and functional point of view. There were no statistically significant changes compared to the physical examination. On radiographs, mobilizations, anchor pull-outs or other complications did not occur in each group. CONCLUSIONS: Shoulder function improved after complete repair of the rotator cuff and similar clinical results were achieved regardless of the material and shape of the suture anchor. The bioabsorbable anchors in innovative open architecture material seem to have results comparable to peek anchors. Unfortunately, further studies are needed to define the advantages in using one material compared to the other. (www.actabiomedica.it).