Low-grade infections in nonarthroplasty shoulder surgery

A Literature Review of Cutibacterium Acnes: From Skin Commensal to Pathogen in Shoulder Surgery

Cutibacterium acnes, previously known as Propionibacterium acnes, is a gram-positive rod in the pilosebaceous glands and commonly implicated in acne vulgaris. Its role in prosthetic joint infections, particularly in shoulder surgeries, has recently gained attention due to its prevalence around the shoulder girdle. This review collates evidence on the pathogenic role of C. acnes in shoulder surgeries, discussing preventive measures, risk factors, clinical presentation, investigation, and treatment strategies. C. acnes infections are complex, often presenting with non-specific symptoms and delayed diagnoses. Risk factors include male sex, presence of hair, shoulder steroid injections, and previous shoulder surgeries. Investigations such as inflammatory markers, synovial fluid analysis, diagnostic arthroscopy, tissue cultures, and advanced molecular techniques like next-generation sequencing and multiplex polymerase chain reaction are explored for their effectiveness in detecting C. acnes. Treatment strategies range from prolonged antibiotics and antibiotic spacers to single-stage and two-stage revision surgeries. Studies indicate that single-stage revision may provide better outcomes compared to two-stage revision. Effective management of C. acnes infections requires careful assessment, relevant investigations, and tailored treatment approaches. This review emphasizes the need for further research to address intraoperative contamination and to develop more efficient diagnostic and treatment methods.

The incidence of subclinical infection in patients undergoing revision shoulder stabilization surgery: a retrospective chart review

BACKGROUND

Shoulder instability continues to be a common problem that is difficult to treat. Part of this difficulty can be attributed to the numerous postoperative complications that can impact the clinical course. Our study aims to primarily identify the incidence of subclinical infection in patients undergoing revision shoulder stabilization surgery and secondarily identify any risk factors for developing a subclinical infection.

MATERIALS AND METHODS

From January 2012 to December 2022, 94 charts of patients who underwent revision surgery by the senior author after a previous arthroscopic or open stabilization surgery for shoulder instability were reviewed. All patients of any age who underwent either bony or soft tissue revision surgery, regardless of the number of previous surgeries or corticosteroid injections, were included. Patients were excluded if they had a previous infection in the shoulder, if there was no record of the procedures performed in the previous surgery, or if cultures were not available for review. For each patient, demographic information (age, sex, race, smoking status, previous corticosteroid injections, malnutrition, renal failure, liver failure, diabetes mellitus, immunocompromised status, and intravenous drug use), surgical information (procedures performed, type of surgery, and date of surgery), and culture results were recorded.

RESULTS

Overall, 107 patients were included in our study. Twenty-nine patients (27.1%) had positive cultures (60 cultures in total). Twenty-six patients had positive Cutibacterium acnes (C. acnes) cultures. On average, C. acnes cultures took 10.65 days to turn positive, whereas 24 of 27 patients had cultures that were positive within 14 days of the culture being obtained. There was no difference in infection incidence rates between soft tissue and bony stabilization procedures (P = .86) or arthroscopic and open procedures (P = .59). Males were more than 5 times more likely than females to be culture positive in our cohort (93.1% vs. 73.1%, relative risk [RR] = 1.27, P = .03). Finally, 10 control cultures were taken from the operating room air environment (8 distinct surgeries had 1 control culture taken, whereas 1 surgery had 2), 2 of which were positive for C. acnes (both taken from the same patient operation). This patient had their shoulder cultures positive for C. acnes as well.

CONCLUSION

More than a quarter of patients requiring revision surgery after shoulder stabilization procedures have a subclinical shoulder infection, with males being at a higher risk of developing an infection than females. Surgeons should always consider infection as a reason for the lack of clinical improvement and possibly needing revision surgery after shoulder stabilization. The prompt diagnosis and treatment of these infections could be vital in improving results after these surgeries.

Pharmacoacupuncture for the Treatment of Frozen Shoulder: protocol for a systematic review and meta-analysis

Objectives

Frozen shoulder (FS) is one of the most challenging shoulder disorders for patients and clinicians. Its symptoms mainly include any combination of stiffness, nocturnal pain, and limitation of active and passive glenohumeral joint movement. Conventional treatment options for FS are physical therapy, nonsteroidal anti-inflammatory drugs, injection therapy, and arthroscopic capsular release, but adverse and limited effects continue to present problems. As a result, pharmacoacupuncture (PA) is getting attention as an alternative therapy for patients with FS. PA is a new form of acupuncture treatment in traditional Korean medicine (TKM) that is mainly used for musculoskeletal diseases. It has similarity and specificity compared to corticosteroid injection and hydrodilatation, making it a potential alternative injection therapy for FS. However, no systematic reviews investigating the utilization of PA for FS have been published. Therefore, this review aims to standardize the clinical use of PA for FS and validate its therapeutic effect.

Methods

The protocol was registered in Prospero (CRD42023445708) on 18 July 2023. Until Aug. 31, 2023, seven electronic databases will be searched for randomized controlled trials of PA for FS. Authors will be contacted, and manual searches will also be performed. Two reviewers will independently screen and collect data from retrieved articles according to predefined criteria. The primary outcome will be pain intensity, and secondary outcomes will be effective rate, Constant-Murley Score, Shoulder Pain and Disability Index, range of motion, quality of life, and adverse events. Bias and quality of the included trials will be assessed using the Cochrane handbook's risk-of-bias tool for randomized trials. Meta analyses will be conducted using Review Manager V.5.3 software. GRADE will be used to evaluate the level of evidence for each outcome.

Results

This systematic review and meta-analysis will be conducted following PRISMA statement. The results will be published in a peer-reviewed journal.

Conclusion

This review will provide scientific evidence to support health insurance policy as well as the standardization of PA in clinical practice.

Analysis of fracture-related infections from Swedish insurance claims between 2011 and 2021

Fracture-related infections (FRI) pose a serious complication with an incidence of 1-2%. This study aimed to analyze compensation claims submitted to The Swedish National Patient Insurance Company (LÖF) because of FRI after closed/open reduction and internal fixation (C/ORIF) in the four most common fracture sites (proximal humerus, distal radius, hip, ankle). Patients registered in the LÖF database with a suspected FRI between 2011 and 2021 were identified by matching International Classification of Diseases and procedural codes indicative of a combination of fractures to the proximal humerus, distal radius, hip and ankle, C/ORIF and infection. Medical records were reviewed for fracture sites, pathogens and complications. Data from the Swedish Fracture Register (SFR) were extracted to estimate the proportion of reported claims to the presumed number of FRI. Of 122 FRI identified in the LÖF database, 34 were after C/ORIF in the proximal humerus, 12 in the distal radius, 28 in the hip and 48 in the ankle. LÖF compensated 111 patients (91%). Median time from C/ORIF to an FRI was 3 weeks (interquartile range 2-6), and 95% of all FRI occurred within 1 year after C/ORIF. Staphylococcus aureus was the most common pathogen in patients with a distal radius, hip and ankle FRI. In contrast, Cutibacterium spp. were the most common aetiology in FRI of the proximal humerus. The total number of fractures treated with C/ORIF in the four fracture sites registered in the SFR during 2021 was 18,711. Most of the FRI patients were diagnosed within the first year after C/ORIF, and 91% of the patients received compensation. Given an expected FRI incidence of 1-2%, our estimates with extrapolated data from the SFR indicate that < 10% of affected patients applied for compensation.

A High Rate of Bacteriologic Culture-Positive Findings Is Seen After Revision Rotator Cuff Surgery

Purpose

To determine the incidence of subclinical infections in patients undergoing revision arthroscopic rotator cuff repair and identify any risk factors for developing these infections.

Methods

Patients who underwent revision surgery by the senior author between January 2012 and December 2022 after a previous rotator cuff surgery were identified. All patients undergoing an open or arthroscopic revision of their previous rotator cuff surgery were included. Patients who had noted previous shoulder infections or had incomplete chart documentation were excluded. For each patient, demographic information, surgical information, and culture results were recorded.

Results

A total of 115 patients were identified. Thirty-nine were excluded due to incomplete chart documentation (35) or a history of infection (4); therefore, 22 patients (28.9%) had positive cultures (31 cultures in total). Seventeen patients had only Cutibacterium acnes identified. C acnes cultures turned positive on average 13.52 days after culture collection. There was no difference in infection incidence rates between isolated rotator cuff repair and rotator cuff repair plus additional surgeries (P = .88) or between initial arthroscopic versus open procedures (P = .83). None of the 12 identified risk factors, including age, sex, race, smoking history, previous corticosteroid injections, malnutrition, renal failure, liver failure, diabetes mellitus, immunocompromised status, intravenous drug use, and number of revisions, were correlated with the presence of a subclinical infection. Finally, 6 patients had control cultures taken. One culture (16.6%) was positive for C acnes, while this patient did not have a positive shoulder culture.

Conclusions

Subclinical shoulder infections can be present in more than one-quarter of patients undergoing revision after rotator cuff repair.

Level of Evidence

Level IV, diagnostic case series.

Septic Olecranon Bursitis With Osteomyelitis Attributed to Cutibacterium acnes: Case Report and Literature Overview of the Dilemma of Potential Contaminants and False-Positives

We report an unusual case of acute septic olecranon bursitis, with probable olecranon osteomyelitis, where the only organism isolated in culture was initially considered a contaminant, Cutibacterium acnes. However, we ultimately considered it the likely causal organism when treatment for most of the other more likely organisms failed. This typically indolent organism is prevalent in pilosebaceous glands, which are scarce in the posterior elbow region. This case illustrates the often challenging empirical management of a musculoskeletal infection when the only organism isolated might be a contaminant, but successful eradication requires continued treatment as if it is the causal organism. The patient is a Caucasian 53-year-old male who presented to our clinic with a second episode of septic bursitis at the same location. Four years prior, he had septic olecranon bursitis from methicillin-sensitive Staphylococcus aureus that was treated uneventfully with one surgical debridement and a one-week course of antibiotics. In the current episode reported here, he sustained a minor abrasion. Cultures were obtained five separate times because of no growth and difficulty eradicating the infection. One culture grew C. acnes on day 21 of incubation; this long duration has been reported. The first several weeks of antibiotic treatment failed to eradicate the infection, which we ultimately attributed to inadequate treatment of C. acnes osteomyelitis. Although C. acnes has a well-known propensity for false-positive cultures as typically reported in post-operative shoulder infections, treatment for our patient's olecranon bursitis/osteomyelitis was successful only after several surgical debridements and a prolonged course of intravenous and oral antibiotics that targeted it as the presumptive causal organism. However, it was possible that C. acnes was a contaminant/superinfection, and another organism was the culprit, such as a Streptococcus or Mycobacterium species that was eradicated by the treatment regime targeted for C. acnes.

Two-stage shoulder arthroplasty after deep infection of the shoulder caused by arthroplasty, osteosynthesis or other surgical procedures: microbial spectrum, complications and functional outcome after at least 1 year follow-up

PURPOSE

Infection represents probably the most challenging complication in shoulder arthroplasty and all other surgical procedures of the shoulder. A deep infection of the shoulder is often combined with a destruction of the joint and a loss of function. In many cases the arthroplasty is the last resort for these patients to obtain a satisfactory function. The objective of this study was to determine outcome data on microbiota and clinical results of a two-stage shoulder arthroplasty procedure after deep infection of the shoulder.

METHODS

Twenty-six patients with a deep shoulder infection after arthroplasty, osteosynthesis, or rotator-cuff repair were included, while two patients had an empyema without prior surgery. All underwent initial surgical debridement with implantation of an antibiotic-loaded spacer, followed by postoperative systemic antibiotics. The patients obtained definitive shoulder arthroplasty in a second surgery. None of the patients had to undergo more than two surgeries before the arthroplasty. The follow-up analysis including microbiota results, complication rates, and functional outcomes could be determined after at least 1 year in 60% of patients (n = 16).

RESULTS

The most frequently detected microorganisms were S. epidermidis (31%, n = 10) and Cutibacterium acnes (19%, n = 6). In 28% (n = 9) of cases multi-drug resistant bacteria were detected and in 35% (n = 8) of cases more than one microorganism was found. The overall revision rate was 42%, 11 of 26 patients, in the first 8 weeks after arthroplasty. Reasons for revision were joint dislocations in 23% (n = 6), 15% (n = 4) postoperative hematomas, one (4%) re-infection and one (4%) periprosthetic fracture. At follow-up after 19.3 ± 5.5 months postoperatively, a mean abduction of 113.4°, anteversion of 122.8° and external rotation of 14° was found, with an average age and gender-adjusted Constant Score of the affected shoulder of 63. The subjects' pain and impairment in normal life measured by a questionnaire with school grades were significantly reduced (p < 0.05) as compared to prior shoulder arthroplasty.

CONCLUSION

The most relevant bacteria in the study cohort were Staphylococcus subspecies and to a lower extent Cutibacterium acnes. A high number of multi-drug resistant and mixed microbiota spectra were detected, defining a need to adapt therapeutic regimen targeting these microbiotas. The two-stage shoulder arthroplasty after a deep infection resulted in excellent infection control with however high early postoperative rates for joint dislocation (23%) and hematomas (15%). At follow-up a stable joint was achieved with a sufficient functional outcome and satisfying outcome for activities of daily living and pain.

CLINICAL TRIAL

Trial registration number: DRKS00016927, date of registration: 2019/03/19.

Postoperative neurologic symptoms in the operative arm after shoulder surgery with interscalene blockade: a systematic review

OBJECTIVE

Postoperative neurologic symptoms (PONS) in the operative arm are important complications of shoulder surgery and interscalene blockade (ISB). This systematic review aimed to compare the risk of PONS between ISB and other techniques, and the relative safety of different agents used in ISB.

METHODS

Our systematic review followed Cochrane review methodology and was registered in PROSPERO. A search of MEDLINE (Ovid), EMBASE (Ovid), and CENTRAL (Wiley) from inception to June 2020 was completed. We included randomized or quasi-randomized trials of patients (> five years old) undergoing shoulder surgery with any ISB technique as an intervention, compared with any other nonregional or regional technique, or ISB of alternate composition or technique. The primary outcome was PONS (study author defined) assessed a minimum of one week after surgery.

RESULTS

Fifty-five studies totalling 6,236 participants (median, 69; range, 30-910) were included. Another 422 otherwise eligible trials were excluded because PONS was not reported. Heterogeneity in when PONS was assessed (from one week to one year) and the diagnostic criteria used precluded quantitative meta-analysis. The most common PONS definition, consisting of one or more of paresthesia, sensory deficit, or motor deficit, was only used in 16/55 (29%) trials. Risk of bias was low in 5/55 (9%) trials and high in 36/55 (65%) trials, further limiting any inferences.

CONCLUSION

These findings highlight the need for a standardized PONS outcome definition and follow-up time, along with routine, rigorous measurement of PONS in trials of ISB.

STUDY REGISTRATION

PROSPERO (CRD42020148496); registered 10 February 2020.

Treatment of partial rotator cuff lesions is associated with a higher frequency of post-operative shoulder stiffness. A prospective investigation on the role of surgery-related risk factors for this complication

PURPOSE

Post-operative shoulder stiffness (SS) is a common complication after arthroscopic rotator cuff (RC) repair. The aim of this prospective study is to evaluate the role of surgical risk factors in the development of this complication, with special focus on the characteristics of the RC tears.

METHODS

Two-hundred and twenty patients who underwent arthroscopic RC repair for degenerative posterosuperior RC tears were included. Surgery-related risk factors for development of post-operative SS belonging to the following five categories were documented and analyzed: previous surgery, RC tear characteristics, hardware and repair type, concomitant procedures, time and duration of surgery. The incidence of post-operative SS was evaluated according to the criteria described by Brislin and colleagues.

RESULTS

The incidence of post-operative SS was 8.64%. The treatment of partial lesions by tear completion and repair technique was significantly associated with development of post-operative SS (p = 0.0083, pc = 0.04). A multivariate analysis revealed that treatment of partial lesions in patients younger than 60 years was associated to a higher risk of developing post-operative SS (p = 0.007). Previously known pre-operative risk factors such as female sex and younger age were confirmed. No other significant associations were documented.

CONCLUSION

The treatment of partial lesions of the RC may lead to a higher risk of post-operative SS than the treatment of complete lesions, in particular in patients younger than 60 years. Possible explanations of this finding are the increased release of pro-inflammatory cytokines caused by the additional surgical trauma needed to complete the lesion and the different pain perception of the subgroup of patients who require surgical treatment already for partial tears.

EVIDENCE

A higher risk of post-operative SS should be expected after tear completion and repair of partial lesions, especially in young patients. Appropriate pre-operative counseling and post-operative rehabilitation should be considered when approaching this subgroup of RC tears.

LEVEL OF EVIDENCE

Prognostic study, level II.

Efficacy of combinational therapy using blue light and benzoyl peroxide in reducing Cutibacterium acnes bioburden at the deltopectoral interval: a randomized controlled trial

BACKGROUND

The purpose of this study was to compare the efficacy of blue light therapy (BLT) and 5% topical benzoyl peroxide (BPO) gel in combination with standard chlorhexidine (CHX) preparation in eradicating Cutibacterium acnes at the deltopectoral interval measured by positive, quantitative culture findings.

METHODS

Adult male volunteers were randomized to 1 of 3 treatment groups: BPO, BLT, and BPO followed by BLT. Contralateral shoulders served as matched controls. Volunteers randomized to BPO applied the gel for a total of 5 treatments. In the BLT group, a single 23-minute treatment was administered at an estimated irradiance of 40 mW/cm² (radiant exposure, 55.2 J/cm²). In the BPO-BLT group, volunteers received both treatments as described earlier. After treatment with either BPO, BLT, or both, a single swab culture was taken from the treatment shoulder. Next, control and treatment shoulders were prepared with CHX, and cultures were taken from each shoulder. Cultures were sent for anaerobic quantitative growth analysis with both polymerase chain reaction and Sanger sequencing confirmation of presumptive C acnes colonies.

RESULTS

This study enrolled 60 male volunteers, 20 per group, with no loss to follow-up. After treatment but prior to CHX administration, all culture samples in the BPO group and BLT group grew C acnes. Prior to CHX, 16 samples (80%) in the BPO-BLT group grew C acnes. On quantitative analysis, the BPO group and BPO-BLT group had significantly less growth of C acnes compared with the BLT group after treatment but prior to CHX (P < .05 for each). Following CHX administration, the BPO and BPO-BLT groups had significantly fewer positive culture findings (odds ratios of 0.03 and 0.29, respectively) and less quantity of growth compared with their control arms (P < .05). This was not seen in the BLT group. For quantitative between-group analysis, no significant synergistic effects were seen with BPO-BLT compared with BPO alone (P = .688). There was no difference in side effects between groups.

CONCLUSION

The combination of topical BPO and CHX was effective at eliminating C acnes in most cases. BLT alone did not demonstrate effective antimicrobial properties against C acnes at the radiant exposure administered in this study. Combining BPO and BLT did not lead to significant synergistic antimicrobial effects. Both BPO and BLT are safe with few, transient side effects reported. More work is needed to determine whether BLT at higher radiant exposures or serial treatment results in bactericidal effects against C acnes in vivo.

Cutibacterium acnes infections in revision surgery for persistent shoulder complaints: a retrospective cohort study

INTRODUCTION

Low-grade Cutibacterium acnes (C. acnes) infections after shoulder surgery usually result in unexplained complaints. The absence of clinical signs of infection makes the incidence unclear and underreported. This study aimed to determine the incidence of C. acnes infections in patients with artificial material and unexplained persistent shoulder complaints. We hypothesized that the incidence of C. acnes infections would be higher in patients with artificial material. Risk factors and associations between culture time and contaminations/infections were also assessed.

MATERIALS AND METHODS

This retrospective cohort study included patients with and without artificial material undergoing revision shoulder surgery for persistent complaints after primary surgery and the suspicion of a low-grade infection. Three-six cultures were taken in all patients. C. acnes infection incidence was determined and logistic regression analysis was performed to identify risk factors. The association between time to culture growth and infections/contaminations was evaluated using Kaplan-Meier analysis and log-rank test.

RESULTS

26/61 (42.6%) patients with and 14/33 (42.2%) without material had a C. acnes infection. Age (OR 0.959; 95% CI 0.914-1.000) and BMI (OR 0.884; 95% CI 0.787-0.977) were risk factors. Time to C. acnes culture positivity was not different between infections and contaminations.

CONCLUSION

The incidence of C. acnes infections was 42.6% in patients with artificial material and 42.2% in patients without artificial material. Younger age and lower BMI are risk factors. Low-grade C. acnes infections should be considered in patients with unexplained persistent complaints following shoulder surgery.

High rate of unexpected positive cultures in presumed aseptic revision of stiff shoulders after proximal humerus osteosynthesis

BACKGROUND

The aim of this study was to investigate the prevalence of positive microbiology samples after osteosynthesis of proximal humerus fractures at the time of revision surgery and evaluate clinical characteristics of patients with positive culture results.

METHODS

All patients, who underwent revision surgery after locked platting, medullary nailing or screw osteosynthesis of proximal humeral fractures between April 2013 and July 2018 were retrospectively evaluated. Patients with acute postoperative infections, those with apparent clinical signs of infection and those with ≤1 tissue or only sonication sample obtained at the time of implant removal were excluded. Positive culture results of revision surgery and its correlation with postoperative shoulder stiffness was analyzed in patients with an interval of ≥6 months between the index osteosynthesis and revision surgery.

RESULTS

Intraoperatively obtained cultures were positive in 31 patients (50%). Cutibacterium acnes was the most commonly isolated microorganism, observed in 21 patients (67.7%), followed by coagulase negative staphylococci in 12 patients (38.7%). There were significantly more stiff patients in the culture positive group compared to the culture-negative group (19/21, 91% vs. 15/26, 58%, p = 0.02). Furthermore, 11 of 12 (91.7%) patients with growth of the same microorganism in at least two samples had a stiff shoulder compared to 23 of 35 (65.7%) patients with only one positive culture or negative culture results (p = 0.14).

CONCLUSION

Infection must always be considered as a possibility in the setting of revision surgery after proximal humerus osteosynthesis, especially in patients with postoperative stiffness.

Pseudomonas aeruginosa infection of shoulder joint after latissimus dorsi tendon transfer: A case report

Infection rates of arthroscopic procedures have been consistently reported at approximately 1% and are even less common in shoulder arthroscopy (0.3%). We are unaware of any prior reports of infection associated with an arthroscopic-assisted latissimus dorsi transfer and report on a 60-year-old male who experienced this event. At the 2-month follow-up, he reported an infection of the shoulder joint, characterized by a fistula on the portal scar. Laboratory tests revealed a Pseudomonas aeruginosa infection which was treated with arthroscopic irrigation and debridement of the shoulder joint followed by oral antibiotics for 6 weeks. At 1-year follow-up no findings of infection were presented. To our knowledge, this is the first case of P. aeruginosa infection of the shoulder after an arthroscopic-assisted latissimus dorsi tendon transfer. Because the empirical pharmacological therapy initially adopted did not produce a clinically important improvement, a more organism-specific antibiotic was used. In conclusion, the key points of positive results were surgical approach with careful washout, debridement of surgical accesses, and targeted antibiotic therapy.

Prevention of Cutibacterium acnes infection in arthroscopic shoulder surgery: a systematic review

BACKGROUND

Cutibacterium acnes is a gram-positive anaerobe that can lead to postoperative shoulder infections. The purpose of this study was to determine the incidence of C acnes infections following shoulder arthroscopy and evaluate the efficacy of perioperative antibiotic prophylaxis in the prevention of these infections.

METHODS

A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify studies that evaluated the prevalence and clinical indications of C acnes infections after various arthroscopic shoulder surgical procedures. Patients were assessed based on positive culture rates, the contraction of infection, and antibiotic regimens used to prevent infection.

RESULTS

A total of 9 studies (1 level I, 5 level II, 1 level III, and 2 level IV) met the inclusion criteria, including a total of 3758 patients with a mean age of 59.9 years (range, 17-87 years) at the time of surgery. The mean follow-up time was 1.6 months (range, 1.0-12.0 months). Overall, 37.3% of patients (173 of 464) had positive C acnes skin and/or joint culture results, and in 0.22% of patients (8 of 3586), a C acnes infection was diagnosed postoperatively. The application of a topical benzoyl peroxide antibiotic in the days leading up to surgery significantly reduced the positive culture rate from 41.6% to 9.6% (P < .001).

CONCLUSIONS

C acnes infections occur at a very low rate (0.22%) following shoulder arthroscopy. The application of a topical benzoyl peroxide antibiotic in the days leading up to surgery in combination with preoperative antibiotic prophylaxis significantly reduces the prevalence of C acnes in shoulder arthroscopy patients.

Exploring Penicillin G as an Intrawound Antibiotic Powder for Prevention of Postoperative Shoulder Infections: Does It Exhibit In Vitro Chondrotoxicity?

Cutibacterium acnes (C. acnes) is a significant insidious pathogen for postoperative infections in shoulder surgery. Studies have demonstrated that certain topical antibiotic powders used have the potential for chondrotoxicity. Benzylpenicillin, commonly referred to as Penicillin G (Pen G) has the lowest minimum inhibitory concentration (MIC) for C. acnes. There is no research regarding the topical application of Pen G during shoulder surgery, nor has its chondrocyte toxicity been previously investigated. This study sought to characterize the in vitro chondrocyte toxicity of Pen G. Culture-derived bovine chondrocytes were exposed to serial Pen G concentrations and compared with a positive and negative control. A negative control of growth medium and positive control of 1% Triton solution. The chondrocyte viability was assessed via spectrophotometer absorbance. The treatment groups were analyzed using one-way repeated measures analysis of variance and Pearson's correlation analysis. The chondrocyte viability was significantly higher for all Pen G concentrations as compared with the positive control (p < 0.001). All concentrations of Pen G exhibited continued chondrocyte metabolic activity over time. Analysis of variance, independent of time, demonstrated no significant decrease in chondrocyte viability for Pen G concentrations ≤6.25 mg/ml, as compared with the negative control (p > 0.05). Pen G demonstrated a significant negative correlation with its concentration and absorbance (r = 0.371, p < 0.001), however, concentrations ≤6.25 mg/ml did not demonstrate a significant decrease in chondrocyte viability (p = 0.063). Pen G in concentrations appropriate for C. acnes is not significantly chondrotoxic and may be safe for intrawound application. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:726-730, 2020.

Incidence and predictors of positive intraoperative cultures in primary shoulder arthroplasty following prior ipsilateral shoulder surgery

Background

To our knowledge, the rate of positive intraoperative cultures in patients undergoing primary shoulder arthroplasty with prior ipsilateral nonarthroplasty shoulder surgery is unknown. The aim of this study was to determine the incidence and predictors of positive cultures in these patients.

Methods

We performed a retrospective review of patients with prior ipsilateral shoulder surgery with intraoperative cultures taken at the time of primary shoulder arthroplasty. We evaluated culture results, demographics, and number of prior surgeries. Regression analysis was used to determine patient-related risk factors that predict positive cultures.

Results

A total of 682 patients underwent primary shoulder arthroplasty, 83 had at least 1 prior ipsilateral shoulder surgery: 65.1% male, mean age 64.2 ± 10.9 years. For the cohort of 83 patients, an average of 3.2 ± 1.2 tissue samples were obtained for each patient, with a mean of 0.84 ± 1.14 tissue cultures being positive (range 0-5). Thirty-seven of the 83 patients (44.5%) had at least 1 positive culture, with Cutibacterium acnes the most frequent organism (31/37; 83.4%). An average of 1.9 ± 0.96 tissue cultures resulted positive (range 1-5) for the 37 patients who had positive cultures, 40.5% (15/37) had only 1 positive tissue culture (12/15 C acnes, 2/15 Staphylococcus epidermidis, and 1/15 vancomycin-resistant enterococcus). Male sex and history of prior shoulder infection were predictive of culture positivity (odds ratios: 2.5 and 20.9, respectively). Age, race, medical comorbidities, number of prior shoulder surgeries, and time from index shoulder surgery were not predictive of culture positivity.

Conclusion

About 45% of patients with no clinical signs of infection and a history of prior ipsilateral shoulder surgery undergoing primary shoulder arthroplasty grew positive intraoperative cultures. The significance of these findings remains unclear with regard to risk of periprosthetic infection and how these patients should be managed.

Failed Latarjet surgery: why, how, and what next?

Background

The Latarjet procedure is an established and popular procedure for recurrent anterior shoulder instability; however, to our knowledge, few studies have reported on the outcomes of revision for failed Latarjet surgery. We reviewed the causes and management of recurrent instability after previous Latarjet stabilization surgery. The outcomes of revision surgery were also evaluated.

Methods

A retrospective analysis of prospective data in patients undergoing revision surgery after failed Latarjet stabilization was conducted. Data were collected over a 5-year period and included patient demographics, clinical presentation, cause of recurrent instability, indications for revision surgery, intraoperative analysis, outcomes of revision surgery, and return to sport.

Results

We identified 16 patients (12 male and 4 female patients) who underwent revision surgery for recurrent instability after Latarjet stabilization. Of these patients, 11 were athletes: 9 professional and 2 amateur athletes. The mean age at revision was 29.9 ± 8.9 years (range, 17-50 years). The indications for revision were anterior instability in 11 patients, posterior instability in 4, and both anterior and posterior instability in 1. Of the anterior instability cases, 54.5% were due to coracoid nonunion and 36.4% were due to capsular failure (retear). All posterior instability cases had posterior capsulolabral injuries, and the mean Beighton score in this group was 6 or higher. One patient had a failed Latarjet procedure with coracoid nonunion and a posterior labral tear.

Conclusion

Coracoid nonunion was the most common cause of recurrence after Latarjet stabilization, requiring an Eden-Hybinette procedure. The patients who returned with posterior instability had a high incidence of hypermobility and could be treated successfully by arthroscopic techniques.

Shoulder Joint Infections with Negative Culture Results: Clinical Characteristics and Treatment Outcomes

Background

The incidence of septic arthritis of the shoulder joint is increasing as the population ages. The prevalence of shoulder infection is also increasing because of the growing use of arthroscopy and expansion of procedures in the shoulder. However, cultures do not always identify all microorganisms, even in symptomatic patients. The incidence of negative cultures ranges from 0% to 25%. Few studies have reported clinical features and treatment outcomes of culture-negative shoulder infections. This cohort study addresses culture-negative shoulder joint infections in nonarthroplasty patients. This study aimed to compare clinical characteristics and treatment outcomes of patients with culture-negative results to those with culture-positive results. Our hypothesis was that culture-negative infections would have more favorable outcomes than culture-positive infections.

Methods

We retrospectively reviewed data of 36 patients (17 culture-negative and 19 culture-positive) with shoulder infections between June 2004 and March 2015. The minimum follow-up duration was 1.2 years (mean, 5 ± 3.8 years; range, 1.2-11 years). We assessed preoperative demographic data and characteristics, laboratory markers, imaging and functional scores, intraoperative findings, and postoperative findings of both groups.

Results

Culture-negative patients (17/36, 47.2%) had a significantly lower occurrence of repeated surgical debridement (culture-negative vs. culture-positive: 1.2 ± 0.4 vs. 2.4 ± 1.7, p = 0.002) without osteomyelitis. In the multiple logistic regression analysis, the presence of osteomyelitis [odds ratio (OR) = 9.7, 95% confidence interval (CI): 1.0-91.8, p=0.04)] and the number of surgical debridements (OR = 5.3, 95% CI: 1.3-21.6, p=0.02) were significantly associated with culture-positive infections.

Conclusions

Culture-negative infections without osteomyelitis are less severe than culture-positive infections. Culture-negative infections can be controlled more easily and are not necessarily a negative prognostic factor for shoulder joint infections.

Polymicrobial anaerobic infection with a deep abscess in the supraspinous fossa following a subacromial corticosteroid injection

In September 2015, a male aged 61 years with poorly controlled diabetes (his only medical problem) had left shoulder surgery that included an arthroscopic acromioplasty with debridement of suture material from a rotator cuff repair done 10 years prior. A subacromial corticosteroid injection was given 7 months later for pain and reduced motion. Three weeks later a fulminate infection was evident. Cultures grew Propionibacterium acnes. Treatment included two arthroscopic debridement surgeries and 8 weeks of intravenous antibiotics (primarily daptomycin). Eight weeks after the cessation of the antibiotics, purulence recurred and tissue cultures then grew Staphylococcus epidermidis. Several additional surgeries were needed to control the infection. We failed to recognise that an abscess that extended from the subacromial space across the entire supraspinous fossa. We report this case to alert clinicians that a seemingly innocuous subacromial corticosteroid injection can lead to an atypical infection and also extend into the supraspinous fossa.

Lack of level I evidence on how to prevent infection after elective shoulder surgery

PURPOSE

Infection is a concern after all orthopedic procedures, including shoulder surgery. This systematic review of literature aimed to determine risk factors for infection as well as the availability and effectiveness of measures utilized to prevent infection after elective shoulder surgery.

METHODS

An electronic database search was performed using MEDLINE (1950-October 2017), EMBASE (1980-October 2017), CINAHL (1982-October 2017), and the Cochrane database to identify studies reporting a risk factor or preventive measure for infection after shoulder surgery.

RESULTS

Fifty-one studies were eligible for inclusion. Risk factors identified for infection were male sex, the presence of hair, receiving an intra-articular cortisone injection within the 3 months prior to surgery, smoking, obesity, and several comorbidities. The only preventive measure with level I evidence was for the use of chlorhexidine wipes for cleansing the skin in the days prior to surgery and for the use of ChloraPrep or DuraPrep over povodine and iodine to prep the skin at the time of surgery. Level II-IV evidence was found for other infection prevention methods such as intravenous antibiotic prophylaxis.

CONCLUSION

There are many risk factors associated with developing an infection after elective shoulder surgery. Many preventive measures have been described which may decrease the risk of infection; however, most lack a high level evidence to support them. The findings of this systematic review are clinically relevant as it has been shown that infection after shoulder surgery results in poor patient-reported outcomes and pose a significant financial burden. As surgeons the goal should be to prevent infections to avoid the morbidity for patients and the increased cost for society.

LEVEL OF EVIDENCE

IV systematic review of literature.

Risk Factors for Shoulder Stiffness: Current Concepts

Shoulder stiffness is a condition of painful restriction of the glenohumeral range of motion. Numerous risk factors for primary and postoperative shoulder stiffness have been described. This article summarizes the known aspects of the pathophysiology of shoulder stiffness, with special attention to elements of molecular biology and genetics, which could influence the risk of developing shoulder stiffness. Furthermore, the role of hormonal and metabolic factors, medical disorders, drugs, and of other published risk factors for primary and postoperative shoulder stiffness is reviewed and discussed. Finally, aspects related to shoulder surgery and postoperative rehabilitation protocols, which could influence the development of postoperative stiffness are presented.