The effect of different antibiotic combinations in calcium sulfate cement on the growth of Cutibacterium acnes and Staphylococcus periprosthetic shoulder infection isolates.

BACKGROUND: Periprosthetic joint infections (PJI) of the shoulder are a devastating complication of shoulder arthroplasty and are commonly caused by Staphylococcus and Cutibacterium acnes. Absorbable calcium sulfate (CS) beads are sometimes used for delivering antibiotics in PJI. This study evaluates the in vitro effect of different combinations of gentamicin, vancomycin, and ertapenem in beads made from CS cement on the growth of C acnes and coagulase-negative Staphylococcus (CNS) strains. METHODS: Three strains of C acnes and 5 strains of CNS from clinically proven shoulder PJI were cultured and plated with CS beads containing combinations of vancomycin, gentamicin, and ertapenem. Plates with C acnes were incubated anaerobically while plates with Staphylococcus were incubated aerobically at 37 °C. Zones of inhibition were measured at intervals of 3 and 7 days using a modified Kirby Bauer technique, and beads were moved to plates containing freshly streaked bacteria every seventh day. This process was run in triplicate over the course of 56 days. Statistical analysis was conducted using SPSS v. 28 with repeated measures analysis of variance (ANOVA) and pairwise comparisons with Tukey correction. RESULTS: In experiments with C acnes, beads containing ertapenem + vancomycin and vancomycin alone formed the largest zones of inhibition over time (P < .001). In experiments with Staphylococcus, beads containing vancomycin alone formed the largest zones of inhibition over time for all 5 strains (P < .001). Zones of inhibition were 1.4x larger for C acnes than for Staphylococcus with beads containing vancomycin alone. For both C acnes and Staphylococcus, beads containing ertapenem had the strongest initial effect, preventing all bacterial growth in C acnes and almost all growth for Staphylococcus during the first week but dropping substantially by the second week. Beads containing gentamicin alone consistently created smaller zones of inhibition than beads containing vancomycin alone, with vancomycin producing zones 5.3x larger than gentamicin in C acnes and 1.3x larger in Staphylococcus (P < .001). DISCUSSION: These data suggest that for both C acnes and Staphylococcal species, CS beads impregnated with vancomycin were most effective at producing a robust antibiotic effect. Additionally, ertapenem may be a viable supplement in order to create a more potent initial antibiotic effect but is not as effective as vancomycin when used alone. Gentamicin alone was not effective in maintaining consistent and long-term antibiotic effects. These results indicate that amongst the antibiotics currently commercially available to be used with CS, vancomycin is consistently superior to gentamicin in the setting of C. acnes and CNS.

The Surgical Outcomes of Pedicle Subtraction Osteotomy per Different First Assistant: Retrospective Analysis of 312 Cases.

INTRODUCTION: Pedicle subtraction osteotomies (PSOs) are complex spinal deformity surgeries that are associated with high complication rates. They are typically done by an experienced spine surgeon with another attending, resident, or physician assistant serving as the first assistant. The purpose of this study was to determine whether selecting a surgical team for single-level PSO based on case difficulty and fusion length could equalize intraoperative and perioperative outcomes among three groups: dual-attending (DA), attending and orthopaedic resident (RS), and attending and physician assistant (PA). METHODS: This study was a retrospective cohort analysis of 312 patients undergoing single-level thoracic or lumbar PSO from January 2007 to December 2020 by a fellowship-trained orthopaedic spine surgeon. Demographic, intraoperative, and perioperative data within 30 days and 2 years of the index procedure were analyzed. RESULTS: Patient demographics did not markedly differ between surgical groups. The mean cohort age was 64.5 years with BMI 31.9 kg/m 2 . Patients with the DA approach had a significantly longer surgical time (DA = 412 min vs. resident = 372 min vs. physician assistant = 323 min; P < 0.001). Patients within the DA group experienced a significantly lower rate of infection (DA = 2.1% [3/140] vs. RS = 7.9% [9/114] vs. PA = 1.7% [1/58], P = 0.043), surgical complication rate (DA = 26% [37/140] vs. RS = 41% [47/114] vs. PA = 33% [19/58], P < 0 .001), and readmission rate (DA = 6.4% [9/140] vs. RS = 12.3% [14/114] vs. PA = 19% [11/58] P = 0.030) within 30 days of surgery. No notable differences were observed among groups in 2-year complication, infection, readmission, or revision surgery rates. CONCLUSIONS: These study results support the DA surgeon approach. Resident involvement, even in less complex cases, can still negatively affect perioperative outcomes. Additional selection criteria development is needed.

Clinical outcomes of reverse total shoulder arthroplasty for elective indications versus acute 3- and 4-part proximal humeral fractures: a systematic review and meta-analysis.

BACKGROUND: Reverse total shoulder arthroplasty (RTSA) has continued to increase in clinical utility and popularity as an effective treatment for cuff tear arthropathy (CTA), irreparable rotator cuff tears (RCTs), osteoarthritis, and acute 3- and 4-part proximal humeral fractures. Performing RTSA for acute proximal humeral fractures presents the unique challenges of tuberosity management, bone loss, and instability compared with elective indications such as CTA or irreparable RCTs. The purpose of this study was to compare the clinical outcomes, active range of motion (ROM), radiographic outcomes, and complications between patients undergoing elective RTSA (RTSA-E) and those undergoing RTSA for fracture (RTSA-F). METHODS: A systematic review of the literature was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. We queried 3 electronic databases (Embase, Cochrane, and PubMed) using the search term "reverse" AND "shoulder" AND "arthroplasty." Studies investigating the clinical outcomes of RTSA for traumatic and/or elective indications were included. Studies were excluded if they included RTSA performed for fracture sequelae, inflammatory arthritis, post-traumatic osteoarthritis, or avascular necrosis. Data collected included patient demographic characteristics, subjective outcome measurements, ROM, and complications. The pooled means and proportions along with their 95% confidence intervals were generated by a random-effects model that incorporated the between-study variations in weighting. RESULTS: A total of 134 studies (11,651 shoulders) investigating the clinical outcomes of RTSA-E patients and 66 studies (3117 shoulders) investigating RTSA-F patients were included in this systematic review. Analysis of patient-reported outcomes demonstrated that RTSA-F patients experienced significantly lower Constant scores than RTSA-E patients; however, relative Constant scores, Simple Shoulder Test scores, Disabilities of the Arm, Shoulder and Hand scores, American Shoulder and Elbow Surgeons scores, and visual analog scale pain scores were similar. RTSA-F patients also had significantly lower forward elevation, abduction, and external rotation. RTSA-F patients experienced tuberosity complications at a significantly higher rate than RTSA-E patients (25.9% vs. 4.1%). There was no significant difference between the 2 groups in terms of other complications such as heterotopic ossification, radiographic loosening, revision, nerve injury, postoperative stiffness, infection, dislocation, and component loosening. DISCUSSION: RTSA performed for acute 3- and 4-part proximal humeral fractures yields overall worse clinical outcomes and active ROM compared with RTSA performed for elective indications including CTA, massive irreparable RCTs, and osteoarthritis with deformity. Tuberosity healing may be a major contributing factor to the difference in clinical outcomes. In the setting of RTSA-F, patient and surgeon expectations may need to be tempered and appropriate measures undertaken to optimize tuberosity healing.

Proximal Long Head Biceps Rupture: A Predictor of Rotator Cuff Pathology.

PURPOSE: To investigate whether acute rupture of the proximal long head biceps is a harbinger of disease of the nearby supraspinatus and subscapularis tendons. METHODS: A retrospective chart review from February 1, 2008, to August 31, 2016, was performed at our institution identifying patients who presented with an acute (<12-week) history of "Popeye" deformity of the distal biceps and a magnetic resonance imaging (MRI) of the affected shoulder. MRI images were then reviewed in duplicate to determine supraspinatus and subscapularis tendon tear incidence, size, chronicity, and depth. The association between rotator cuff status and acute long head biceps rupture as well as patient age, sex, smoking status, hand dominance, and history of diabetes mellitus or trauma was then evaluated. RESULTS: A total of 116 patients were included in this study (mean age: 61.9 ± 10.9 years). A significant proportion (n = 99; incidence: 85%) were found to have some degree of supraspinatus or subscapularis tendon tearing on MRI (P < .001). These patients were also found to be significantly older compared with those with an intact rotator cuff (mean age 63.3 ± 10.7 vs 54.2 ± 9.2; P = .001). Full thickness rotator cuff tears were significantly more likely to involve the supraspinatus as opposed to the subscapularis (incidence: 44% and 21%; P = .002). CONCLUSIONS: Despite the expected association of rotator cuff disease with increasing patient age, the results of this study also affirm the hypothesis that inflammation in the rotator cuff interval signaled by rupture of the long head of biceps is a harbinger of rotator cuff disease. Clinicians should have a high index of suspicion regarding concomitant anterosuperior rotator cuff pathology in patients presenting with acute long head of biceps rupture. Early evaluation with advanced imaging should be strongly considered. LEVEL OF EVIDENCE: Level IV, case series.