The Impact of Hospital Size and Teaching Status on Outcomes Following Total Ankle Arthroplasty.

The popularity and utilization of total ankle arthroplasty (TAA) as treatment for ankle arthritis has increased exponentially from 1998 to 2012. Overall the outcomes have improved for TAA with the introduction of new-generation implants and this has increased the focus on optimizing other variables affecting outcomes for TAA. The purpose of this study was to examine the effects of hospital characteristics and teaching status on outcomes for TAA. The Nationwide Inpatient Sample database was queried from 2002 to 2012 using the ICD-9 procedure code for TAA. The primary outcomes evaluated included: in-hospital mortality, length of stay, total hospital charges, discharge disposition, perioperative complications, and patient demographics. Analyses were carried out based on hospital size: small, medium, and large; and teaching status: rural nonteaching, urban nonteaching, and urban teaching. A total weighted national estimate of 16,621 discharges for patients undergoing TAA was reported over the 10-year period. There were significant differences in length of stay and total charges between all hospitals when comparing location and teaching status; however, no significant differences were noted for in-hospital mortality. Rural, nonteaching hospitals had higher odds of perioperative complications. There were also significant differences in length of stay and total charges when comparing hospital sizes. Overall, there is no increased risk of mortality after TAA regardless of hospital size or setting. However, rural hospitals had increased rates of perioperative complications compared to urban hospitals. Our analyses demonstrated important factors affecting cost and resource utilization for TAA, clearly additional work is needed to optimize this relationship, especially in the upcoming bundled payment models.

The role of greater tuberosity healing in reverse shoulder arthroplasty: a finite element analysis.

BACKGROUND: The lack of greater tuberosity (GT) healing in proximal humerus fractures has been negatively correlated with outcomes for hemiarthroplasty; however, there is still debate regarding the effects of GT healing in reverse shoulder arthroplasty (RSA). Our goal was to examine the effects of GT healing using a kinematic finite element analysis (FEA) model. MATERIAL AND METHODS: Computer-aided design models of a medialized glenoid with a lateralized humerus (MGLH) RSA design were uploaded into an FEA shoulder model in 2 different configurations: healed greater tuberosity (HGT) and nonunion greater tuberosity (NGT). Deltoid muscle forces and joint reaction forces (JRFs) on the shoulder were calculated during abduction (ABD), forward flexion (FF), and external rotation (ER). RESULTS: Force magnitude of the anterior, middle, and posterior deltoid muscle as well as JRFs modeled in both GT scenarios were similar for ABD (muscle forces P = .91, P = .75, P = .71, respectively; and JRF P = .93) and for FF (muscle forces P = .89, P = .83, P = .99, respectively; and JRF P = .90). For ER, the force magnitude between 2 GT settings showed statistically significant differences (HGT: 9.51 N vs. NGT: 6.13 N) (P < .001). Likewise, during ER, JRFs were different, and the NGT group showed a steep drop in JRF after 10° of ER (HGT: 28.4 N vs. NGT: 18.38 N) (P < .001). CONCLUSION: GT healing does not seem to impact RSA biomechanics during abduction or forward flexion; however, it does affect biomechanics during external rotation. Overall orthopedic surgeons can expect good results for patients after RSA even with poor GT healing.

Efficacy of Imaging Modalities Assessing Fatty Infiltration in Rotator Cuff Tears.

BACKGROUND: Fatty atrophy is a diagnosis characterized by the combination of fatty infiltration and muscle atrophy of the rotator cuff. Studies have shown a strong positive correlation between the level of fatty infiltration and the risk of experiencing a chronic rotator cuff tear. Therefore, the purpose of the present study was to review the current literature on radiographic imaging of fatty infiltration and fatty atrophy to better aid surgeons in predicting functional outcome and to help guide patient decisions. METHODS: We conducted a literature search in PubMed. The exact search queries included "rotator cuff" in the MeSH Terms field; "fatty atrophy," fatty infiltration," and "fatty muscle degeneration" in the Title/Abstract field; and various combinations of these searches. We initially found 184 articles using these keywords, including both human and animal studies. The 25 animal studies were excluded, leaving 159 articles. The abstracts of all remaining articles were reviewed and selected on the basis of our inclusion criteria of focusing on patients with rotator cuff tears (preoperatively and postoperatively), fatty infiltration, fatty atrophy, and imaging modalities. We excluded an additional 127 articles, leaving 32 articles that were selected for the final review and inclusion in this study. RESULTS: Among 45 shoulder specialists across different studies, interrater agreement for Goutallier staging with use of magnetic resonance imaging (MRI) ranged from 0.24 to 0.82 and intrarater agreement for supraspinatus fatty changes ranged from 0.34 to 0.89. Our review also showed strong positive correlations when assessing the severity of fatty atrophy of the rotator cuff between MRI and ultrasound or ultrasound modalities such as sonoelastography. CONCLUSIONS: Increasing fatty infiltration of the rotator cuff is associated with greater repair failure rates and hence poorer overall clinical outcomes. MRI remains the gold standard for the imaging of rotator cuff tears and postoperative healing. Ultrasound can decrease health-care expenditures associated with the assessment of repair integrity postoperatively, although ultrasound is not as precise and has some limitations compared with MRI.

Biomechanical comparison of 2 augmented glenoid designs: an integrated kinematic finite element analysis.

BACKGROUND: Augmented glenoid implants are available to help restore the biomechanics of the glenohumeral joint with excessive retroversion. It is imperative to understand their behavior to make a knowledgeable preoperative decision. Therefore, our goal was to identify an optimal augmented glenoid design based on finite element analysis (FEA) under maximum physiological loading. METHODS: FEA models of 2 augmented glenoid designs-wedge and step-were created per the manufacturers' specifications and virtually implanted in a scapula model to correct 20° of retroversion. Simulation of shoulder abduction was performed using the FEA shoulder model. The glenohumeral force ratio, relative micromotion, and stress levels on the cement mantle, glenoid vault, and backside of the implants were compared between the 2 designs. RESULTS: The force ratio was 0.56 for the wedge design and 0.87 for the step design. Micromotion (combination of distraction, translation, and compression) was greater for the step design than the wedge design. Distraction measured 0.05 mm for the wedge design and 0.14 mm for the step component. Both implants showed a similar pattern for translation; however, compression was almost 3 times greater for the step component. Both implants showed high stress levels on the cement mantle. At the glenoid vault and on the implants, the stress levels were 1.65 MPa and 6.62 MPa, respectively, for the wedge design and 3.78 MPa and 13.25 MPa, respectively, for the step design. CONCLUSION: Implant design slightly affects joint stability; however, it plays a major role regarding long-term survival. Overall, the augmented wedge design provides better implant fixation and stress profiles with less micromotion.

The effect of glenohumeral radial mismatch on different augmented total shoulder arthroplasty glenoid designs: a finite element analysis.

BACKGROUND: Augmented glenoid implants to correct bone loss can possibly reconcile current prosthetic failures and improve long-term performance for total shoulder arthroplasty. Biomechanical implant studies have suggested benefits from augmented glenoid components, but limited evidence exists on optimal design. METHODS: An integrated kinematic finite element analysis (FEA) model was used to evaluate optimal augmented glenoid design based on biomechanical performance in translation in the anteroposterior plane similar to clinical loading and failure mechanisms with osteoarthritis. Computer-aided design software models of 2 different commercially available augmented glenoid designs-wedge (Equinox; Exactech, Inc., Gainesville, FL, USA) and step (STEPTECH; DePuy Synthes, Warsaw, IN, USA) were created according to precise manufacturer's dimensions of the implants. Using FEA, they were virtually implanted to correct 20° of retroversion. Two glenohumeral radial mismatches, 3.5/4 mm and 10 mm, were evaluated for joint stability and implant fixation simulating high-risk conditions for failure. RESULTS: The wedged and step designs showed similar glenohumeral joint stability under both radial mismatches. Surrogate for micromotion was a combination of distraction, translation, and compression. With similar behavior and measurements for distraction and translation, compression dictated micromotion (wedge: 3.5 mm = 0.18 mm and 10 mm = 0.10 mm; step: 3.5 mm = 0.19 mm and 10 mm = 0.25 mm). Stress levels on the backside of the implant and on the cement mantle were higher using a step design. DISCUSSION: Greater radial mismatch has the advantage of providing higher glenohumeral stability with tradeoffs, such as higher implant and cement mantle stress levels, and micromotion worse when using a step design.

Comparison of Microbial Count on Various Surfaces in Operating Rooms at Different Times of the Day.

The purpose of this study was to determine the degree of microbial contamination of surfaces in the operating room (OR) and to understand the relationship between time and location of contamination. Five OR surfaces were sampled at two time points on three consecutive Mondays and Thursdays. Each sample was cultured on a blood agar plate and introduced to a liquid nutrient broth. The most sterile surface was the OR lights with only one positive growth sample at each time. At both times, the most commonly contaminated surface was the staff keyboard. Coagulase-negative staphylococcus was the most common isolated species. Contamination rate of OR surfaces was not affected by time of day or day of the week. Simple cleaning and daily decontamination of staff keyboards can significantly reduce bacterial burdens and should be of primary importance to optimize OR sterility. (Journal of Surgical Orthopaedic Advances 27(4):281-285, 2018).

The impact of preoperative opioid use on outcomes after arthroscopic rotator cuff repair.

BACKGROUND: Preoperative opioid use has been correlated to suboptimal outcomes in orthopedic surgery. This study evaluated the effect of preoperative opioid use on outcomes after arthroscopic rotator cuff repair (RCR). METHODS: A retrospective review was performed of 79 patients who underwent arthroscopic RCR; of these, 31 with a history of preoperative opioid use were compared with a control group of 48 patients without a history of preoperative opioid use. Preoperative and postoperative patient-reported outcomes and functional scores were compared. RESULTS: Both cohorts significantly improved on all patient-reported shoulder scores; however, the nonopioid group demonstrated significantly better postoperative patient-reported outcome scores (P = .015) and external rotation measurement (P = .008). Functional outcomes also significantly improved from preoperatively to postoperatively for forward flexion, but no differences were seen between groups. CONCLUSIONS: Patients with a history of preoperative opioid use can still achieve significant improvements in outcomes after arthroscopic RCR, although not to the same extent as opioid-naïve patients. Therefore, orthopedic surgeons must consider a patient's preoperative opioid use and temper expectations with regard to outcomes so that they are able to set realistic postoperative goals for patients undergoing RCR.