Operative Treatment of Acromial and Scapular Spine Fracture Nonunions Complicating Reverse Total Shoulder Arthroplasty.

BACKGROUND: Fractures of the acromion and spine can have a major impact on the outcome of reverse shoulder arthroplasty (RSA) with respect to pain, motion, and function. Reports on internal fixation for these fractures are isolated to small series or case reports with variable outcomes. The purpose of this study was to report on the outcome of open reduction and internal fixation (ORIF) of acromion or spine fractures encountered before or after RSA and describe our evolution of fixation techniques. METHODS: Between 2011 and 2023, 22 fractures or nonunions of the acromion or spine of the scapula underwent ORIF at a single institution and were followed for a minimum of 1 year. In 16 shoulders, fractures occurred after RSA, whereas 5 shoulders underwent ORIF prior to RSA. One shoulder had undergone prior failed ORIF elsewhere and revision ORIF was performed at our institution. There were 10 males and 12 females with a mean age of 67 (SD=15.1) years. Fixation strategies included single (n=11) and double plate fixation (n=11). Kruskal-Wallis one-way analyses of variance were used to analyze continuous variables and Chi-square tests employed for categorical variables. RESULTS: Of the 5 fractures treated with ORIF pre-RSA, 1 shoulder suffered an additional fracture medial to the hardware and 1 required additional bone grafting for incomplete union at the time of RSA. These 5 shoulders all underwent RSA uneventfully, but one fracture experienced late displacement of the scapular spine nonunion, leading to plate removal. Of the 16 post-RSA ORIF shoulders, radiographic union was confirmed in 14 and substantial residual inferior angulation identified in 3. New fractures occurred after ORIF in 5 shoulders. For patients who underwent ORIF after RSA, pain scores improved from a mean of 8 to 1.9 points, with more modest elevation gains (58.2° to 91.3° pre- and postoperatively, respectively). CONCLUSIONS: ORIF of acromion and scapular spine fractures or nonunions in the setting of RSA have the potential to lead to union. When these fractures and nonunions are encountered prior to RSA, ORIF allows for uneventful RSA implantation, but secondary displacement may occur. ORIF seems to lead to improvements in pain, but more modest improvements in motion and function. Our fixation strategy has evolved to (1) dual plating, (2) spanning the whole length of the spine with one of the plates, (3) use of hook features under the acromion or os trigonum if possible, and (4) liberal use of bone graft.

Acute versus delayed radial head arthroplasty for the treatment of radial head fractures.

BACKGROUND: Radial head arthroplasty (RHA) is an important tool in the acute treatment of comminuted radial head and neck fractures. RHA is also performed in a delayed manner after failed open reduction and internal fixation, for fracture malunion or nonunion, and other chronic post-traumatic elbow disorders where restoration of the lateral column of the elbow is considered necessary. The relative efficacy and longevity of acute vs. delayed RHA is unknown. We sought to compare clinical, radiographic, and patient-reported outcomes between these groups. METHODS: We identified patients ≥18 years old who underwent an RHA between 2000 and 2018 and then extracted 135 total elbows with a mean follow-up of 2.3 years that sustained isolated radial head fractures (30%), terrible triad injuries (66%), or Essex-Lopresti injuries (4%). The acute cohort (RHA: <12 weeks) contained 101 elbows that underwent surgery at a mean of 0.6 weeks (range, 0 days to 7 weeks, 96% <2 weeks) from injury, whereas the delayed cohort (RHA: 12 weeks to 2 years) contained 34 elbows that underwent surgery at a mean of 36 weeks (range, 14-82 weeks) from injury. Patients in the acute group had a higher percentage of terrible triad injuries (75% vs. 40%, P < .001) and Mason 3 fractures (98% vs. 45%, P < .001). RESULTS: At the final follow-up, 13 of 101 patients in the acute cohort (13%) and 7 of 34 patients in the delayed cohort (21%) required implant revision or resection. A total of 25 patients (25%) in the acute cohort and 12 patients (35%) in the delayed cohort required a reoperation. Kaplan-Meier 2-year survival estimates free of implant resection or revision (90% acute, 86% delayed) and reoperation (76% acute, 70% delayed) were similar between groups. In patients with 5-year follow-up, there was an increased rate of revision or resection in the delayed group (30% vs. 13%). Two-year survival estimates free of radiographic loosening were 80% in the acute cohort vs. 57% in the delayed cohort (P = .04). Mayo Elbow Performance Score at 2 years demonstrated mean scores of 83 and 79 in the acute and delayed groups, respectively, with 71% of the acute cohort and 64% of the delayed cohort achieving good or excellent scores. CONCLUSIONS: Our results demonstrated that although 2-year Kaplan-Meier survival free of revision or resection estimates and reoperation rates was equivalent between the groups, the delayed group experienced worse Mayo Elbow Performance Score outcomes, a higher revision or resection rate at 5 years, and an increased rate of radiographic loosening.

Does proximal versus distal injury location of the medial ulnar collateral ligament of the elbow differentially impact elbow stability? An ultrasound-guided and robot-assisted biomechanical study.

BACKGROUND: The location (proximal vs. distal) of elbow medial ulnar collateral ligament (MUCL) tears impacts clinical outcomes of nonoperative treatment. The purposes of our study were to (1) determine whether selective releases of the MUCL could be performed under ultrasound (US) guidance without disrupting overlying soft tissues, (2) assess the difference in medial elbow stability for proximal and distal releases of the MUCL using stress US and a robotic testing device, and (3) elucidate the flexion angle that resulted in the greatest amount of medial elbow laxity after MUCL injury. METHODS: Sixteen paired, fresh-frozen elbow specimens were used. Valgus laxity was evaluated with both US and robotic-assisted measurements before and after selective MUCL releases. A percutaneous US-guided technique was used to perform proximal MUCL releases in 8 elbows and to perform distal MUCL releases in their matched pairs. The robot was used to determine the elbow flexion angle at which the maximum valgus displacement occurred for both proximally and distally released specimens. Open dissection was then performed to assess the accuracy of the percutaneous releases. RESULTS: Percutaneous US-guided releases were successfully performed in 15 of 16 specimens. The proximal release resulted in greater valgus angle displacement (11° ± 2°) than the distal release (8° ± 2°) between flexion angles of 30° and 70° (P < .0001 at 30°, P < .0001 at 40°, P = .001 at 50°, P = .005 at 60°, and P = .020 at 70°). Valgus displacement between release locations did not reach the level of statistical significance between 80° and 120° (P = .051 at 80°, P = .131 at 90°, P = .245 at 100°, P = .400 at 110°, and P = .532 at 120°). When we compared the values for the mean increase in US delta gap (stressed - supported state) from before to after MUCL release, the proximally released elbows had larger increases than the distally released elbows (5.0 mm proximal vs. 3.7 mm distal, P = .032). After MUCL release, maximum mean valgus displacement occurred at 49° of flexion. CONCLUSIONS: US-guided selective releases of the MUCL can be performed reliably without violating the overlying musculature. Valgus instability is not of greater magnitude for distal releases when compared with proximal releases. This findings suggests there must be alternative factors to explain the difference in clinical prognosis between distal and proximal tears. The observed flexion angle for maximum valgus laxity could have important implications for elbow positioning during US or fluoroscopic stress examination, as well as surgical repair or reconstruction of the MUCL.

Metric Selection, Metric Targets, and Risk Adjustment Should be Considered in the Design of Gainsharing Models for Bundled Payment Programs in Total Joint Arthroplasty.

BACKGROUND: Under bundled payment models, gainsharing presents an important mechanism to ensure engagement and reward innovation. We hypothesized that metric selection, metric targets, and risk adjustment would impact surgeons' performance in gainsharing models. METHODS: Patients undergoing total joint arthroplasty at an urban health system from 2017 to September 2018 were included. Gainsharing metrics included the following: length of stay, % discharge-to-home, 90-day readmission rate, % of patients with episode spend under target price, and % of patients with patient-reported outcomes (PROs) collected. Four scenarios were created to evaluate how metric selection/adjustment impacted surgeons' performance designation: scenario 1 used "aspirational targets" (>60th percentile), scenario 2 used "acceptable targets" (>50th percentile), scenario 3 risk-adjusted surgeon performance prior to comparing aspirational targets, and scenario 4 included a PRO collection metric. Number of metrics achieved determined performance tier, with higher tiers getting a greater share of the gainsharing pool. RESULTS: In total, 2776 patients treated by 12 surgeons met inclusion criteria (mean length of stay 3.0 days, readmission rate 4.0%, discharge-to-home 74%, episode spend under target price 85%, PRO collection 56%). Lowering of metric targets (scenario 1 vs. 2) resulted in a 75% increase in the number of high performers and 98% of the gainsharing pool being eligible for distribution. Risk adjustment (scenario 3) caused 50% of providers to move to higher performance tiers and potential payments to increase by 28%. Adding the PRO metric did not change performance. CONCLUSION: Quality metric/target selection and risk adjustment profoundly impact surgeons' performance in gainsharing contracts. This impacts how successful these contracts can be in driving innovation and dis-incentivizing the "cherry picking" of patients. LEVEL OF EVIDENCE: Level III.

A SANE Approach to Outcome Collection? Comparing the Performance of Single- Versus Multiple-Question Patient-Reported Outcome Measures After Total Hip Arthroplasty.

BACKGROUND: Several patient-reported outcome measures (PROMs) exist to measure outcomes after total hip arthroplasty (THA) but can be limited by patient-perceived burden and completion rates. We analyzed whether the modified single assessment numerical evaluation (M-SANE), a one-question PROM, would perform similarly to multiple-question PROMs among patients undergoing primary THA. METHODS: Patients undergoing THA completed the Patient-Reported Outcomes Measurement Information System-10 (PROMIS-10), the Hip Disability and Osteoarthritis Outcomes Score Junior (HOOS-Jr), and M-SANE questionnaires both preoperatively and postoperatively. The M-SANE assessment asked patients to assess their hip on a scale from 0 to 10, with 10 being the best possible score. Validity of M-SANE compared with other PROMs was determined by Spearman's correlation and floor and ceiling effects. Responsiveness was analyzed using standardized response mean (SRM). RESULTS: One hundred and thirty six patients with at least 1-year follow-up were reviewed. The average M-SANE score improved from 3.3 preoperatively to 7.1 at one year postoperatively. There was moderate to strong correlation at one-year follow-up between the M-SANE and HOOS-Jr (ρ = 0.75, P < .001) and PROMIS-10 physical component summary (ρ = 0.63, P < .001). Floor and ceiling effects of the M-SANE (floor 2.0%, ceiling 21.3%) were comparable to the HOOS-Jr (floor 0.0%, ceiling 20.8%). The responsiveness of the M-SANE after THA (SRM = 1.06, 95% CI: 0.79-1.33) was comparable to HOOS-Jr (SRM = 1.33, 95% CI: 1.08-1.59) and superior to PROMIS-10 physical component summary (SRM = 0.65, 95% CI: 0.55-0.74). CONCLUSION: The M-SANE has performed similarly across multiple psychometric properties compared with more burdensome PROMs in assessing longitudinal patient-reported outcomes after THA.

Mapping the Diffusion of Technology in Orthopaedic Surgery: Understanding the Spread of Arthroscopic Rotator Cuff Repair in the United States.

BACKGROUND: The mechanism by which surgical innovation is spread in orthopaedic surgery is not well studied. The recent widespread transition from open to arthroscopic rotator cuff repair techniques provides us with the opportunity to study the spread of new technology; doing so would be important because it is unclear how novel orthopaedic techniques disseminate across time and geography, and previous studies of innovation in healthcare may not apply to the orthopaedic community. QUESTIONS/PURPOSES: (1) How much regional variation was associated with the adoption of arthroscopic rotator cuff repair in the United States Medicare population between 2006 and 2014 and how did this change over time? (2) In which regions of the United States was arthroscopic rotator cuff repair first adopted and how did it spread geographically? (3) Which regional factors were associated with the adoption of this new technology? METHODS: We divided the United States into 306 hospital referral regions based upon referral patterns observed in the Centers for Medicare & Medicaid Services MedPAR database, which records all Medicare hospital admissions; this has been done in numerous previous studies using methodology introduced by the Dartmouth Atlas. The proportion of arthroscopic rotator cuff repairs versus open rotator cuff repairs in each hospital referral region was calculated using adjusted procedural rates from the Medicare Part B Carrier File from 2006 to 2014, as it provided a nationwide sample of patients, and was used as a measure of adoption. A population-weighted, multivariable linear regression analysis was used to identify regional characteristics independently associated with adoption. RESULTS: There was substantial regional variation associated with the adoption of arthroscopy for rotator cuff repair as the percentage of rotator cuff repair completed arthroscopically in 2006 ranged widely among hospital referral regions with a high of 85.3% in Provo, UT, USA, and a low of 16.7% in Seattle, WA, USA (OR 30, 95% CI 17.6 to 52.2; p < 0.001). In 2006, regions in the top quartiles for Medicare spending (+9.1%; p = 0.008) independently had higher adoption rates than those in the bottom quartile, as did regions with a greater proportion of college-educated residents (+12.0%; p = 0.009). The Northwest region (-14.4%; p = 0.009) and the presence of an academic medical center (-5.8%; p = 0.026) independently had lower adoption than other regions and those without academic medical centers. In 2014, regions in the top quartiles for Medicare spending (+5.7%; p = 0.033) and regions with a greater proportion of college-educated residents (+9.4%; p = 0.005) independently had higher adoption rates than those in the bottom quartiles, while the Northwest (-9.6%; p = 0.009) and Midwest regions (-5.1%; p = 0.017) independently had lower adoption than other regions. CONCLUSION: The heterogeneous diffusion of arthroscopic rotator cuff repair across the United States highlights that Medicare beneficiaries across regions did not have equal access to these procedures and that these discrepancies continued to persist over time. A higher level of education and increased healthcare spending were both associated with greater adoption in a region and conversely suggest that regions with lower education and healthcare spending may pursue innovation more slowly. There was evidence that regions with academic medical centers adopted this technology more slowly and may highlight the role that private industry and physicians in nonacademic organizations play in surgical innovation. Future studies are needed to understand if this later adoption leads to inequalities in the quality and value of surgical care delivered to patients in these regions. LEVEL OF EVIDENCE: Level III, therapeutic study.

Identifying regional characteristics influencing variation in the utilization of rotator cuff repair in the United States.

BACKGROUND: There is a lack of consensus regarding indications for surgical management of rotator cuff disease, which can lead to increased regional variation. The objectives of this study were to describe the geographic variation in rates of rotator cuff repair (RCR) in the United States over time and to identify regional characteristics associated with utilization. METHODS: The United States was divided into 306 hospital referral regions. The adjusted per capita RCR rate was calculated using procedural counts derived from the Medicare Part B Carrier File from 2004-2014. Population-weighted multivariable regression was used to identify regional characteristics independently associated with utilization in 2014. RESULTS: In 2014, an 8-fold difference in rates of RCR was found between regions. Between 2010 and 2014, the overall rate of RCR grew only 3.6% and regional variation decreased. Higher regional utilization of several other orthopedic procedures (P < .02), as well as the regional supply of orthopedic surgeons (P = .002), was independently associated with significantly increased utilization. The South, Southeast, and Southwest were independently associated with significantly higher utilization (P < .001) compared with the Northeast. A higher prevalence of resident physicians, a marker of the academic presence within a region, was independently associated with decreased utilization (P < .001). CONCLUSION: Utilization of RCR has increased substantially over the past decade, but the rate of growth appears to be slowing. RCR remains a procedure with significant regional variation, and increased utilization across regions is associated with higher orthopedic surgeon supply and increased rates of other orthopedic procedures.

Acute versus delayed reverse total shoulder arthroplasty for the treatment of proximal humeral fractures in the elderly population: a systematic review and meta-analysis.

BACKGROUND: Recent literature has shown that acute reverse total shoulder arthroplasty (RTSA) yields good outcomes in the treatment of displaced proximal humeral fractures, and there have also been recent studies showing that delayed RTSA can be successfully used for sequelae of proximal humeral fractures such as nonunion and malunion. The use of meta-analysis affords the opportunity to formally compare the outcomes of acute RTSA for fracture and delayed RTSA for fracture sequelae. METHODS: We searched the MEDLINE, Embase, and Cochrane Library databases. We included all studies reporting on RTSA for the treatment of proximal humeral fracture sequelae with a comparison group of acute RTSA or with no comparison group in adults with a mean age older than 65 years and at least 2 years of follow-up. We calculated weighted mean differences for range of motion, standardized mean differences for clinical outcome scores, and relative risks for dichotomous outcomes. RESULTS: Sixteen studies met the inclusion criteria, which comprised 322 patients undergoing RTSA for fracture sequelae. Of these studies, 4 were comparative (46 patients) whereas 12 were case series (276 patients). Among studies directly comparing acute versus delayed RTSA, no differences in forward flexion (P = .72), clinical outcome scores (P = .78), or all-cause reoperation (P = .92) were found between the 2 groups. Patients undergoing delayed RTSA achieved 6° more external rotation than those undergoing acute RTSA; this difference was significant (P = .01). CONCLUSIONS: Given the risks associated with surgery in the elderly population, consideration may be given to an initial trial of nonoperative treatment in these patients, saving RTSA for those in whom nonoperative treatment fails without compromising the ultimate outcome.

Next-Generation Sequencing vs Culture-Based Methods for Diagnosing Periprosthetic Joint Infection After Total Knee Arthroplasty: A Cost-Effectiveness Analysis.

BACKGROUND: Periprosthetic joint infection (PJI) after total knee arthroplasty is challenging to diagnose. Compared with culture-based techniques, next-generation sequencing (NGS) is more sensitive for identifying organisms but is also less specific and more expensive. To date, there has been no study comparing the cost-effectiveness of these two methods to diagnose PJI after total knee arthroplasty. METHODS: A Markov, state-transition model projecting lifetime costs and quality-adjusted life years (QALYs) was constructed to determine the cost-effectiveness from a societal perspective. The primary outcome was incremental cost-effectiveness ratio, with a willingness-to-pay threshold of $100,000/QALY. Sensitivity analyses were performed to evaluate parameter assumptions. RESULTS: At our base case values, culture was not determined to be cost-effective compared to NGS, with an incremental cost-effectiveness ratio of $422,784 per QALY. One-way sensitivity analyses found NGS to be the cost-effective choice above a pretest probability of 45.5% for PJI. In addition, NGS was cost-effective if its sensitivity was greater than 70.0% and its specificity greater than 94.1%. Two-way sensitivity analyses revealed that the pretest probability and test performance parameters (sensitivity and specificity) were the largest factors for identifying whether a particular strategy was cost-effective. CONCLUSION: The results of our model suggest that the cost-effectiveness of NGS to diagnose PJI depends primarily on the pretest probability of PJI and the performance characteristics of the NGS technology. Our results are consistent with the idea that NGS should be reserved for clinical contexts with a high pretest probability of PJI. Further study is required to determine the indications and subgroups for which NGS offers clinical benefit.

A One-Question Patient-Reported Outcome Measure Is Comparable to Multiple-Question Measures in Total Knee Arthroplasty Patients.

BACKGROUND: Patient-reported outcome measures (PROMs) are important for tracking outcomes following total knee arthroplasty (TKA) but can be limited by time constraints and patient compliance. We sought to evaluate the utility of the one-question, modified single assessment numerical evaluation (M-SANE) score in TKA patients compared to legacy PROMs. METHODS: Patients undergoing TKA completed the Patient-Reported Outcomes Measurement Information System-10 (PROMIS-10), the Knee Disability and Osteoarthritis Outcomes Score Junior (KOOS Jr), and M-SANE (modified-SANE) assessments both preoperatively and postoperatively. The M-SANE score asked patients to rate their native or prosthetic knee on a scale from 0 to 10, with 10 being the best function. M-SANE validity was determined by the Spearman's correlation between the collected PROMs and the Bland-Altman plots. PROM responsiveness was assessed using the standardized response mean. RESULTS: In total, 217 patients completed PROMs preoperatively and at 1 year postoperatively. Floor and ceiling effects of the M-SANE were higher than other PROMs but still relatively low (4%-11%). There was a moderate to strong correlation at nearly all time points between the M-SANE and KOOS Jr (ρ = 0.44-0.78, P < .001). There was a weak correlation between the M-SANE and PROMIS physical component summary at the preoperative evaluation (ρ = 0.28) but a strong correlation at 1-year follow up (0.65, P < .001). The long-term responsiveness of the M-SANE to TKA (standardized response mean [SRM] = 0.98, 95% confidence interval [CI] 0.80-1.17) was comparable to both the KOOS Jr (SRM = 1.19, 95% CI 1.00-1.38) and PROMIS physical component summary (SRM = 0.82, 95% CI 0.74-0.91). Bland-Altman plots demonstrated that the M-SANE and KOOS Jr capture combined knee pain and functionality differently. CONCLUSION: The M-SANE score was comparable to validated multiple-question PROMs in TKA patients. The demonstrated validity of the M-SANE, as well as its comparable responsiveness to more lengthy PROMs, highlights its use as a one-question PROM for assessment of patient undergoing TKA.

Patient Outcomes After Total Knee Arthroplasty in Patients Older Than 80 Years.

BACKGROUND: Patients aged 80 and above who suffer from end-stage osteoarthritis may benefit from total knee arthroplasty (TKA), but at high potential risk. Additionally, there is controversy about whether functional improvement in patients above age 80 is similar to younger patients. We compared functional improvement, length of stay (LOS), and facility discharge rates after TKA between this cohort and patients less than 80 years of age. METHODS: We completed a retrospective cohort study comparing TKA patients aged 80 and above with all patients younger than 80. We utilized data from a prospectively collected institutional repository of 2308 TKAs performed from April 2011 through July 2016 at an academic medical center in the United States. We performed multivariable logistic regression to determine the association between age group and clinically significant improvement in the Patient-Reported Outcome Measurement Information System (PROMIS)-10 physical component summary (PCS) score. Secondary outcomes included the magnitude of PCS change, LOS, and facility discharge. RESULTS: There were 175 (7.6%) TKAs in patients older than 80 years compared with 2133 TKAs in patients younger than 80. Patients over 80 had similar adjusted odds of achieving clinically significant PCS improvement following TKA (P = .366), and there was no statistical difference in adjusted postoperative PCS improvement between the 2 age groups. Age 80 and above was associated with a longer adjusted LOS and demonstrated increased odds of facility discharge (odds ratio 4.11, P < .001) after TKA. CONCLUSION: Following TKA, patients older than 80 years demonstrate similar adjusted functional improvement in comparison to younger patients. However, older patients did require substantially more resources as they remained in the hospital longer and were discharged to rehabilitation more often.

Are Barbed Sutures Associated With 90-day Reoperation Rates After Primary TKA?

BACKGROUND: Studies have suggested that barbed sutures for wound closure in TKAs are an acceptable alternative to standard methods. However others have observed a higher risk of wound-related complications with barbed sutures. QUESTIONS/PURPOSES: (1) Do 90-day TKA reoperation rates differ between patients undergoing a barbed suture arthrotomy closure compared with a traditional interrupted closure? (2) Do the 90-day reoperation rates of wound-related, deep infection, and arthrotomy failure complications differ between barbed suture and traditional closures? METHODS: A retrospective analysis of a longitudinally maintained institutional primary TKA database was conducted on all TKAs performed between April 2011 and September 2015. We compared 884 primary TKAs, where the arthrotomy was closed with a barbed suture, with 1598 primary TKAs closed with the standard interrupted suture. After barbed sutures were introduced at our institution in 2012, the majority of surgeons gradually switched to barbed suture closures, with many using them exclusively by the end of the data collection period. We confirmed in-person followups and available data past 90 days for 97.4% (1556 of 1598) of the knees in patients with standard sutures and 94.8% (838 of 884) of the knees in patients with barbed sutures. Our primary endpoint was all-cause 90-day reoperation; our secondary endpoints considered: wound-related reoperation, as defined by previous studies; deep infection per Musculoskeletal Infection Society guidelines; and arthrotomy failure, defined intraoperatively as an opening or dehiscence through the previous arthrotomy closure. T tests and chi-square analyses were used to determine differences between the suture cohorts, and bivariate logistic regression was used to determine associations with our 90-day reoperation outcomes. RESULTS: With the numbers available, there was no association between suture type and 90-day all-cause reoperation (odds ratio [OR], 1.70; 95% CI, 0.82-3.53; p = 0.156). Suture type was not associated with wound-related reoperation (OR, 2.73; 95% CI, 0.97-7.69; p = 0.058). A 0.6% (five of 884) arthrotomy failure rate was observed in the barbed cohort while no (0 of 1598) arthrotomy failures were noted in the traditional group (p = 0.003). Deep infections were rare in both groups (two of 884 barbed sutures, 0 of 1598 standard sutures) and could not be compared. CONCLUSIONS: Although we saw no difference in overall and wound-related 90-day reoperation rates by suture type with the numbers available, we observed a higher frequency in our secondary question of arthrotomy failures when barbed sutures are used for arthrotomy closure during TKA. Given the widespread use of this closure technique, our preliminary pilot results warrant further investigation in larger multicenter cohorts. LEVEL OF EVIDENCE: Level III, therapeutic study.

Chemoselective tarantula toxins report voltage activation of wild-type ion channels in live cells.

Electrically excitable cells, such as neurons, exhibit tremendous diversity in their firing patterns, a consequence of the complex collection of ion channels present in any specific cell. Although numerous methods are capable of measuring cellular electrical signals, understanding which types of ion channels give rise to these signals remains a significant challenge. Here, we describe exogenous probes which use a novel mechanism to report activity of voltage-gated channels. We have synthesized chemoselective derivatives of the tarantula toxin guangxitoxin-1E (GxTX), an inhibitory cystine knot peptide that binds selectively to Kv2-type voltage gated potassium channels. We find that voltage activation of Kv2.1 channels triggers GxTX dissociation, and thus GxTX binding dynamically marks Kv2 activation. We identify GxTX residues that can be replaced by thiol- or alkyne-bearing amino acids, without disrupting toxin folding or activity, and chemoselectively ligate fluorophores or affinity probes to these sites. We find that GxTX-fluorophore conjugates colocalize with Kv2.1 clusters in live cells and are released from channels activated by voltage stimuli. Kv2.1 activation can be detected with concentrations of probe that have a trivial impact on cellular currents. Chemoselective GxTX mutants conjugated to dendrimeric beads likewise bind live cells expressing Kv2.1, and the beads are released by channel activation. These optical sensors of conformational change are prototype probes that can indicate when ion channels contribute to electrical signaling.

Cell Cycle-dependent Changes in Localization and Phosphorylation of the Plasma Membrane Kv2.1 K+ Channel Impact Endoplasmic Reticulum Membrane Contact Sites in COS-1 Cells.

The plasma membrane (PM) comprises distinct subcellular domains with diverse functions that need to be dynamically coordinated with intracellular events, one of the most impactful being mitosis. The Kv2.1 voltage-gated potassium channel is conditionally localized to large PM clusters that represent specialized PM:endoplasmic reticulum membrane contact sites (PM:ER MCS), and overexpression of Kv2.1 induces more exuberant PM:ER MCS in neurons and in certain heterologous cell types. Localization of Kv2.1 at these contact sites is dynamically regulated by changes in phosphorylation at one or more sites located on its large cytoplasmic C terminus. Here, we show that Kv2.1 expressed in COS-1 cells undergoes dramatic cell cycle-dependent changes in its PM localization, having diffuse localization in interphase cells, and robust clustering during M phase. The mitosis-specific clusters of Kv2.1 are localized to PM:ER MCS, and M phase clustering of Kv2.1 induces more extensive PM:ER MCS. These cell cycle-dependent changes in Kv2.1 localization and the induction of PM:ER MCS are accompanied by increased mitotic Kv2.1 phosphorylation at several C-terminal phosphorylation sites. Phosphorylation of exogenously expressed Kv2.1 is significantly increased upon metaphase arrest in COS-1 and CHO cells, and in a pancreatic ß cell line that express endogenous Kv2.1. The M phase clustering of Kv2.1 at PM:ER MCS in COS-1 cells requires the same C-terminal targeting motif needed for conditional Kv2.1 clustering in neurons. The cell cycle-dependent changes in localization and phosphorylation of Kv2.1 were not accompanied by changes in the electrophysiological properties of Kv2.1 expressed in CHO cells. Together, these results provide novel insights into the cell cycle-dependent changes in PM protein localization and phosphorylation.

Anterior hip dislocation 5 months after hip arthroscopy.

Hip dislocation subsequent to hip arthroscopy is a rare complication. We report on a case of low-energy anterior hip dislocation that occurred 5 months after hip arthroscopy, a period notably longer than any previously reported event. The patient was a track and field athlete who presented and received treatment for a labral tear and cam lesion. The athlete then dislocated her hip postoperatively during competitive jumping, a motion that requires significant hip flexion and extension. The most likely cause of the anterior dislocation was failure to close the capsule at the completion of surgery, lending credibility to recent trends in the literature suggesting routine capsular closure. We believe that a partial psoas release also contributed to dynamic hip instability because of increased femoral anteversion in this patient. This case suggests that hip capsule closure should be considered at the completion of every procedure and that a psoas release should be avoided in patients with significant anteversion. Furthermore, the biomechanics of competitive jumping may make these athletes more prone to dislocation and require more conservative return-to-sport recommendations.

The association of metabolic syndrome markers with adhesive capsulitis.

BACKGROUND: Research has associated adhesive capsulitis with diabetes mellitus but suggests that glucose-mediated injury may begin before diabetes is diagnosed. The period preceding diabetes is often marked by metabolic syndrome. METHODS: We investigated the relationship between metabolic syndrome components (insulin resistance, hypertension, dyslipidemia, and obesity) and the development of adhesive capsulitis using a case-control study. We retrospectively reviewed 150 consecutive adhesive capsulitis patient charts to determine the prevalence of obesity and of medications used for treating metabolic syndrome elements and compared these with previously reported nationwide values. RESULTS: The prevalence of anti-hyperglycemia medications in the adhesive capsulitis cohort was 18.4% (95% confidence interval [CI], 12.9%-25.7%), twice the national rate of diagnosed diabetes of 7.6% (95% CI, 6.7%-8.5%). In the 20- to 39-year-old group, the prevalence of anti-hyperglycemic medications, 26.3% (95% CI, 11.8%-48.8%), was over 10 times the nationwide rate. The overall prevalence of hypertensive medication use in the adhesive capsulitis group, 33.1% (95% CI, 25.9%-41.2%), was notably higher than the nationwide rate, 21.6% (95% CI, 19.8%-23.4%). In the 40- to 64-year-old group, the prevalence of hypertensive medication use, 36.8% (95% CI, 28.6%-46.0%), was notably higher than the nationwide rate of 24.5% (95% CI, 22.2%-27.0%). The prevalence of anti-lipid medications and obesity was similar between the groups. CONCLUSIONS: The relationship between adhesive capsulitis and metabolic syndrome remains unclear. Our results confirm previous work associating hyperglycemia with adhesive capsulitis. We have also shown a possible association of hypertension, part of metabolic syndrome and a proinflammatory condition, with adhesive capsulitis, which has not been previously described.

Unplanned hip arthroplasty imposes clinical and cost burdens on treating institutions.

BACKGROUND: Emergent surgery has been shown to be a risk factor for perioperative complications. Studies suggest that patient morbidity is greater with an unplanned hip arthroplasty, although it is controversial whether unplanned procedures also result in higher patient mortality. The financial impact of these procedures is not fully understood, as the costs of unplanned primary hip arthroplasties have not been studied previously. QUESTIONS/PURPOSES: We asked: (1) What are the institutional costs associated with unplanned hip arthroplasties (primary THA, hemiarthroplasty, revision arthroplasty, including treatment of periprosthetic fractures, dislocations, and infections)? (2) Does timing of surgery (urgent/unplanned versus elective) influence perioperative outcomes such as mortality, length of stay, or need for advanced care? (3) What diagnoses are associated with unplanned surgery and are treated urgently most often? (4) Do demographics and insurance status differ between admission types (unplanned versus elective hip arthroplasty)? METHODS: We prospectively followed all 419 patients who were admitted to our Level I trauma center in 2011 for procedures including primary THA, hemiarthroplasty, and revision arthroplasty, including the treatment of periprosthetic fractures, dislocations, and infections. Fifty-seven patients who were treated urgently on an unplanned basis were compared with 362 patients who were treated electively. Demographics, admission diagnoses, complications, and costs were recorded and analyzed statistically. RESULTS: Median total costs were 24% greater for patients admitted for unplanned hip arthroplasties (USD 18,206 [USD 15,261-27,491] versus USD 14,644 [USD 13,511-16,309]; p < 0.0001) for patients admitted for elective arthroplasties. Patients with unplanned admissions had a 67% longer median hospital stay (5 days [range, 4-9 days] versus 3 days [range, 3-4 days]; p < 0.0001) for patients with elective admissions. Mortality rates were equivalent between groups (p = 1.0). Femoral fracture (p < 0.0001), periprosthetic fracture (p = 0.01), prosthetic infection (p = 0.005), and prosthetic dislocation (p < 0.0001) were observed at higher rates in the patients with unplanned admissions. These patients were older (p = 0.04), less likely to have commercial insurance (p < 0.0001), more likely to be transferred from another institution (p < 0.0001), and more likely to undergo a revision procedure (p < 0.0001). CONCLUSIONS: Unplanned arthroplasty and urgent surgery are associated with increased financial and clinical burdens, which must be accounted for when considering bundled quality and reimbursement measures for these procedures.

Transfer of hip arthroplasty patients leads to increased cost and resource utilization in the receiving hospital.

Factors other than complexity of care often drive the transfer of orthopedic patients to tertiary centers. We sought to compare the demographics, diagnoses, insurance data, peri-operative outcomes and institutional costs of total hip arthroplasty patients transferred from outside facilities with those of patients derived from our clinics. We analyzed 419 consecutive patients as part of a prospective risk study. Transferred patients were older (P=0.01), less likely to have private insurance (P<0.0001), and more likely to be admitted on weekends (P=0.04). Both dislocation and fracture were more prevalent in transferred patients (P=0.04; P=0.003). Across all key metrics - including length of stay, mortality scoring, peri-operative complications, and direct and total costs - transferred patients more significantly strained the resources of our arthroplasty center.

Rotator cuff repair in patients with inflammatory arthritis: satisfactory midterm outcomes.

Background: We aimed to evaluate midterm patient-reported outcomes and reoperation rates following rotator cuff repair in patients with either rheumatoid arthritis (RA) or other inflammatory arthritis (nonRA-IA) diagnoses. Methods: We identified all patients with either RA or nonRA-IA who underwent a rotator cuff repair at our institution between 2008 and 2018. IA diagnoses included RA, systemic lupus erythematosus, psoriatic arthritis, and other unspecified inflammatory arthritis. We compiled a cohort of 51 shoulders, with an average follow-up time of 7.0 years. The average age was 60 years (range 39-81), and 55% of patients were female. Patients were contacted via phone to obtain patient-reported outcomes surveys. Univariate linear regression was used to evaluate associations between patient characteristics and outcomes. Results: A review of preoperative radiographs demonstrated that 50% of patients presented with some degree of glenohumeral joint inflammatory degeneration. At the final follow-up, the mean visual analog score for pain was 2 (range 0-8), and the mean American Shoulder and Elbow Surgeons score (ASES) was 77 (standard deviation [SD] = 19). The mean subjective shoulder value was 75% (SD = 22%), and the average satisfaction was 9 (SD 1.9). The mean Patient-Reported Outcomes Measurement Information System upper extremity score was 41 (SD = 10.6). Female sex and a complete tear (vs. partial) were both associated with lower ASES scores, whereas no other characteristics were associated with postoperative ASES scores. The 5-year Kaplan-Meier survival estimate free of reoperation was 91.8% (95% confidence interval 83.0-99.8). Conclusions: Rotator cuff repair in patients with RA or other inflammatory arthritis diagnoses resulted in satisfactory patient-reported outcomes that seem comparable to rotator cuff repair when performed in the general population. Furthermore, reoperations were rare, with a 5-year survival rate free of reoperation for any reason of over 90%. Altogether, an inflammatory arthritis diagnosis should not preclude by itself attempted rotator cuff repair surgery in these patients.

Long-Term Patient-Reported Outcomes After Arthroscopic Debridement of Grade 3 or 4 Capitellar Osteochondritis Dissecans Lesions.

BACKGROUND: Arthroscopic debridement for osteochondritis dissecans (OCD) lesions of the capitellum is a relatively common and straightforward surgical option for failure of nonoperative management. However, the long-term outcomes of this procedure remain unknown. HYPOTHESIS: Arthroscopic debridement of capitellar OCD would provide satisfactory long-term improvement in patient-reported outcomes. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Patients aged ≤18 years who underwent arthroscopic debridement procedures for OCD lesions (International Cartilage Repair Society grades 3 and 4) were identified. Procedures included loose body removal when needed and direct debridement of the lesion; marrow stimulation with drilling or microfracture was added at the discretion of each surgeon. The cohort consisted of 53 elbows. Patient evaluation included visual analog scale for pain; motion; subjective satisfaction; Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) scores; reoperation; and rate of return to sports. RESULTS: At a mean 11 years of follow-up (range, 5-23 years), the median visual analog scale score for pain was 0, and 96% of patients reported being improved as compared with how they were before surgery. The mean ± SD QuickDASH score was 4 ± 9 points (range, 0-52 points), and 80% of patients returned to their sports of interest. The arc of motion significantly improved from 115°± 28° preoperatively to 130°± 17° at latest follow-up (P = .026). Seven elbows (13%) required revision surgery for OCD lesions, resulting in high rates of overall survivorship free of revision surgery: 90% (95% CI, 80%-96%) at 5 years and 88% (95% CI, 76%-94%) at 10 years. At final follow-up, 7 all-cause reoperations were performed without revision surgery on the OCD lesion. CONCLUSION: Arthroscopic debridement of grade 3 or 4 OCD lesions of the capitellum produced satisfactory patient-reported outcomes in a majority of elbows, although a subset of patients experienced residual symptoms. The inherent selection bias of our cohort should be considered when applying these results to the overall population with OCD lesions, as we do not recommend this procedure for all patients.