Preoperative prophylactic antibiotics administration does not influence culture yield in revision shoulder arthroplasty.

BACKGROUND: The importance of administrating prophylactic antibiotics prior to a surgical procedure is well established. Given the difficulty in diagnosing shoulder periprosthetic infections, which are more indolent in nature, some advocate holding prophylactic antibiotics prior to obtaining cultures as there is a concern antibiotics may lead to a false negative culture result. The purpose of this study is to determine whether administration of antibiotics prior to obtaining cultures in revision shoulder arthroplasty influences culture yield. METHODS: This was a retrospective analysis of revision shoulder arthroplasty cases performed at a single institution between 2015 and 2021. During the study period, each surgeon had a standardized protocol that dictated whether antibiotics were given or held prior to each revision surgery. Each case was categorized into either a Preculture antibiotic group, if antibiotics were administered prior to incision, or a Postculture antibiotic group if antibiotics were administered after incision and obtaining cultures. The International Consensus Meeting (ICM) scoring criteria provided by the Musculoskeletal Infection Society was used to categorize the probability of periprosthetic joint infection for each case. Culture positivity was calculated as the ratio of positive cultures and total number of cultures obtained. RESULTS: One hundred twenty-four patients met inclusion criteria. There were 48 patients in the Preculture group and 76 patients in the Postculture group. No significant difference in patient demographics or ICM criteria (P = .09) was observed between the 2 groups. With regard to culture positivity, there was no difference between the Preculture antibiotic group and the Postculture antibiotic group (16% vs. 15%, P = .82, confidence interval = 8%-25% vs. 10%-20%, respectively). CONCLUSION: In the setting of revision shoulder arthroplasty, timing of antibiotic administration did not significantly influence culture yield. This study supports the use of prophylactic antibiotics prior to obtaining cultures in revision shoulder arthroplasty.

The Opioid Risk Tool Correlates With Increased Postsurgical Opioid Use Among Patients With Orthopedic Trauma.

The aim of this study was to determine whether the Opioid Risk Tool (ORT), which has been validated in patients with chronic pain, relates to postoperative opioid consumption. The purpose was to investigate a tool that could help identify patients with orthopedic trauma at high risk for opioid abuse. Patients 18 to 80 years old presenting between May 2018 and August 2018 to UNC Hospitals with isolated orthopedic injuries that required surgical intervention were considered for inclusion. At 2 weeks postoperatively, the ORT was administered. At 6 weeks postoperatively, total morphine milligram equivalents (MME) was determined for each patient. Each patient was also categorized as either low risk (LR) or moderate to high risk (M-HR) based on the cumulative ORT score. Finally, opioid prescriptions provided after 6 weeks postoperatively was recorded. One hundred four patients met the inclusion criteria, and 42 completed the questionnaire. Thirty patients were categorized as LR and 12 patients as M-HR. Patients who were at M-HR consumed a significantly higher MME than LR patients (LR=406 [95% CI, 287-526]; M-HR=824 [95% CI, 591-1057]; P=.001). Linear regression analysis showed that for each additional risk factor, opioid consumption increased by 61 MME, and approximately 58% of the variation in opioid consumption could be explained by the ORT (beta=61, R2=0.58, P=.02). In this study, the ORT predicted which patients would have increased opioid consumption after orthopedic trauma surgery. Each additional risk factor correlated with increased opioid use. The ORT did not predict which patients would continue to receive opioid prescriptions after 6 weeks postoperatively. [Orthopedics. 2023;46(4):e219-e222.].

Rehabilitation and Return to Work and Sport After Rotator Cuff.

This review covers a systematic approach to rehabilitation following rotator cuff repair. Rates of return to work and return to a prior level of sports activity in patients that have undergone rotator cuff repair will be reviewed. Risk factors and predictors of a patient's inability to return to work or prior level of sports participation will be discussed. Overall, there is a high level of return to work and sports following rotator cuff repair. Heavy manual laborers are at higher risk of not returning to a prior level of work, whereas professional overhead athletes are at higher risk of not returning to their prior level of play following rotator cuff repair.

Arthroscopically Assisted Acromioclavicular and Coracoclavicular Reconstruction with a Looped Braided Polyester Suture Band and Buckle Device.

Acromioclavicular (AC) joint injuries occur with a traumatic load to the lateral aspect of the shoulder and account for 9% of all shoulder girdle injuries. Rockwood classified AC joint injuries as type I though type VI, based on severity of injury, radiographic findings, and reducibility of the AC joint. Type I and II injuries are typically managed nonoperatively, whereas type IV, V, and VI are managed operatively to address the significant soft tissue disruption, persistent AC joint instability, and apical shoulder deformation. Treatment of type III injuries remain controversial. Several techniques have been described to treat AC joint injuries with no consensus for optimal treatment. "Anatomic" double-tunnel coracoclavicular ligament reconstruction is one currently popular technique to address AC joint injuries; however, clavicle and coracoid fractures are well-described complications of this technique. The objective of this technical report is to describe our preferred technique to address AC joint injuries. This technique involves using a looped braided polyester prosthetic band and low-profile buckle with allograft augmentation using a device to pass materials around the coracoid process.

Fixed- vs. variable-angle humeral neck cut in anatomic total shoulder arthroplasty: a randomized controlled trial.

BACKGROUND: Variable neck-shaft angle (NSA) stemmed humeral components have been incorporated into certain implant designs to better re-create normal anatomy in total shoulder arthroplasty (TSA). The purpose of this study was to determine if premorbid glenohumeral joint anatomy is better restored with a fixed- vs. variable-NSA prosthesis. METHODS: A randomized controlled trial was performed including 50 patients with osteoarthritis indicated for primary anatomic TSA. Patients were randomized preoperatively to receive either a variable- (n = 26) or fixed-NSA (n = 24) prosthesis. Humeral neck cut in the variable-NSA group matched the patient's anatomic neck, with prosthetic NSA of 127.5°, 132.5°, and 137.5° available. Fixed-NSA cuts were made with an intramedullary guide of 132.5°. Preoperative and postoperative radiographs were evaluated for specific radiographic anatomic variables: NSA, head thickness, tuberosity-to-head height, head offset, articular arc, greater tuberosity offset, and center of rotation (COR). Postoperative radiographic criteria were compared between groups. RESULTS: No differences were found between groups in demographics or preoperative radiographic measures. When comparing average difference in preoperative and postoperative measurements in the fixed-NSA group, the humeral head offset from the humeral shaft axis significantly decreased by 1.4 mm (P = .046), and the COR moved superiorly (3.0 mm, P = .002) without significant medialization or lateralization. In the variable angle group, humeral head offset decreased but did not reach significance (1.2 mm, P = .091), and the COR also moved superiorly (2.9 mm, P < .001) without significant medialization or lateralization. All remaining radiographic parameters did not significantly change from pre- to postoperative imaging. In comparing the fixed- and variable-NSA groups' net change from the premorbid measurements, no significant differences were found in tuberosity-to-head height, head offset, or COR position in both the horizontal and vertical planes. CONCLUSIONS: Both fixed- and variable-NSA anatomic TSA humeral components demonstrate adequate restoration of premorbid anatomy radiographically.

Shoulder Synovitis Does not Affect Pain After Arthroscopic Rotator Cuff Repair.

Background: The goal of this study was to determine if there is an association between glenohumeral synovitis and early post-operative pain after arthroscopic rotator cuff repair. Methods: Fifty patients with symptomatic rotator cuff tears were prospectively enrolled prior to RCR. Baseline ASES score, VAS Pain score, forward elevation, and external rotation were recorded. Intra-operatively, synovitis was graded on a scale of zero to six as based on a previously validated scoring system. VAS Pain scores were obtained from patients post-operatively on days one through 14, week 6, and 3 months. Results: Average intra-operative synovitis score was 2.4 ± 1.6. No significant correlation was found between synovitis score and pre-operative forward elevation (P=0.171), external rotation (P=0.126), VAS Pain (P=0.623), or ASES (P=0.187) scores. No significant correlation was found between synovitis score and post-operative VAS Pain level at any time point. There was a moderate correlation between both pre-operative VAS Pain and ASES scores and post-operative VAS Pain in the first post-operative week. Workers' compensation patients had worse pain at 3 months post-operatively compared to non-workers compensation patients (P=0.038). Conclusion: This study reveals that macroscopically assessed glenohumeral synovitis does not have any significant correlation with pre-operative or post-operative pain in patients undergoing arthroscopic rotator cuff repair; although higher pre-operative pain levels, worse pre-operative ASES scores, and workers compensation status do influence post-operative pain levels in arthroscopic rotator cuff repair.

Musculoskeletal Health Literacy is Associated With Outcome and Satisfaction of Total Knee Arthroplasty.

BACKGROUND: The purpose of this study was to investigate if there is an association between musculoskeletal health literacy with outcome and satisfaction after total knee arthroplasty (TKA). METHODS: A cross-sectional study was performed at our tertiary center to include patients between one and six years postoperatively after primary TKA. Patients were provided a survey including basic demographics, validated musculoskeletal health literacy scale (Literacy in Musculoskeletal Problems), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and TKA satisfaction (whether they would choose to undergo the same operation again). Patients were categorized as either low or normal health literacy based on number of questions (cutoff 6 out of 9) answered correctly on the Literacy in Musculoskeletal Problems. Statistical analysis included multivariate regression with significance at P < .05. RESULTS: Four hundred fifty-three individuals fully completed the survey of eligible participants. Two hundred ninety-six individuals (65.3%) had normal health literacy, and one hundred fifty-seven individuals (34.7%) had low health literacy. Average WOMAC (/96) was 18.0 ± 19.7 in the low and 12.1 ± 15.4 in the normal health literacy groups. Patients with low health literacy had significantly higher WOMAC (worse function) than those with normal health literacy (P = .001). Patients with normal musculoskeletal health literacy were significantly more likely to undergo the same operation again (P = .01, odds ratio 2.163). CONCLUSION: This study shows that patients with low musculoskeletal health literacy have worse outcome scores and are less likely to be satisfied with their TKA. By identifying these patients preoperatively, emphasis can be placed on enhancing procedure expectations and understanding to improve outcome measures and overall satisfaction.

Assessment of registration accuracy during computer-aided oncologic limb-salvage surgery.

PURPOSE: Computer-aided surgery is used in musculoskeletal tumor procedures to improve the surgeon's orientation to local anatomy during tumor resection. For the navigation system to function correctly, preoperative imaging (e.g., CT, MR) must be registered to the patient in the operating room. The goals of this study were (1) to directly quantify registration accuracy in computer-aided tumor surgery and (2) to validate the "system reported error" (SRE) of the navigation system. METHODS: Registration accuracy was evaluated in eight bone sarcoma cases by determining the location of the anatomical paired-points used for registration following surface matching. Coordinates of specific intraoperative post-registration points were compared with the corresponding coordinates in preoperative CT scans to determine the measurement error (ME). RESULTS: The mean difference between post-registration points and planned registration points was 12.21±6.52 mm significantly higher than the mean SRE (0.68 ± 0.15 mm; p = 0.002; 95 % CI 6.11-16.96 mm). The SRE poorly correlated with the calculated ME (R(2) = 0.040). Anatomical paired-point registration with surface matching results in a substantial shift in the post-registration coordinates of the same paired-points used for registration, and this shift is not represented by the SRE. CONCLUSION: The SRE of a surgical navigation system was poorly correlated with direct measurements obtained in musculoskeletal tumor surgery. Improvement in registration accuracy is needed to better navigate tumor boundaries and ensure clear margins while maximally preserving the unaffected tissues and reducing operative morbidity.

Muscarinic excitation of parvalbumin-positive interneurons contributes to the severity of pilocarpine-induced seizures.

OBJECTIVE: A common rodent model in epilepsy research employs the muscarinic acetylcholine receptor (mAChR) agonist pilocarpine, yet the mechanisms underlying the induction of pilocarpine-induced seizures (PISs) remain unclear. Global M1 mAChR (M1 R) knockout mice are resistant to PISs, implying that M1 R activation disrupts excitation/inhibition balance. Parvalbumin-positive (PV) inhibitory neurons express M1 Rs, participate in cholinergically induced oscillations, and can enter a state of depolarization block (DB) during epileptiform activity. Here, we test the hypothesis that pilocarpine activation of M1 Rs expressed on PV cells contributes to PISs. METHODS: CA1 PV cells in PV-CRE mice were visualized with a floxed YFP or hM3Dq-mCherry adeno-associated virus, or by crossing PV-CRE mice with the RosaYFP reporter line. To eliminate M1 Rs from PV cells, we generated PV-M1 knockout (KO) mice by crossing PV-CRE and floxed M1 mice. Action potential (AP) frequency was monitored during application of pilocarpine (200 µm). In behavioral experiments, locomotion and seizure symptoms were recorded in wild-type (WT) or PV-M1 KO mice during PISs. RESULTS: Pilocarpine significantly increased AP frequency in CA1 PV cells into the gamma range. In the continued presence of pilocarpine, a subset (5/7) of PV cells progressed to DB, which was mimicked by hM3Dq activation of Gq-receptor signaling. Pilocarpine-induced depolarization, AP firing at gamma frequency, and progression to DB were prevented in CA1 PV cells of PV-M1 KO mice. Finally, compared to WT mice, PV-M1 KO mice were associated with reduced severity of PISs. SIGNIFICANCE: Pilocarpine can directly depolarize PV+ cells via M1 R activation, but a subset of these cells progress to DB. Our electrophysiologic and behavioral results suggest that this mechanism is active during PISs, contributing to a collapse of PV-mediated γ-aminobutyric acid (GABA)ergic inhibition, dysregulation of excitation/inhibition balance, and increased susceptibility to PISs.

Direct excitation of parvalbumin-positive interneurons by M1 muscarinic acetylcholine receptors: roles in cellular excitability, inhibitory transmission and cognition.

Parvalbumin-containing (PV) neurons, a major class of GABAergic interneurons, are essential circuit elements of learning networks. As levels of acetylcholine rise during active learning tasks, PV neurons become increasingly engaged in network dynamics. Conversely, impairment of either cholinergic or PV interneuron function induces learning deficits. Here, we examined PV interneurons in hippocampus (HC) and prefrontal cortex (PFC) and their modulation by muscarinic acetylcholine receptors (mAChRs). HC PV cells, visualized by crossing PV-CRE mice with Rosa26YFP mice, were anatomically identified as basket cells and PV bistratified cells in the stratum pyramidale; in stratum oriens, HC PV cells were electrophysiologically distinct from somatostatin-containing cells. With glutamatergic transmission pharmacologically blocked, mAChR activation enhanced PV cell excitability in both CA1 HC and PFC; however, CA1 HC PV cells exhibited a stronger postsynaptic depolarization than PFC PV cells. To delete M1 mAChRs genetically from PV interneurons, we created PV-M1 knockout mice by crossing PV-CRE and floxed M1 mice. The elimination of M1 mAChRs from PV cells diminished M1 mAChR immunoreactivity and muscarinic excitation of HC PV cells. Selective cholinergic activation of HC PV interneurons using Designer Receptors Exclusively Activated by Designer Drugs technology enhanced the frequency and amplitude of inhibitory synaptic currents in CA1 pyramidal cells. Finally, relative to wild-type controls, PV-M1 knockout mice exhibited impaired novel object recognition and, to a lesser extent, impaired spatial working memory, but reference memory remained intact. Therefore, the direct activation of M1 mAChRs on PV cells contributes to some forms of learning and memory.