Current and Future Applications of Fluorescence Guidance in Orthopaedic Surgery

Fluorescence-guided surgery (FGS) is an evolving field that seeks to identify important anatomic structures or physiologic phenomena with helpful relevance to the execution of surgical procedures. Fluorescence labeling occurs generally via the administration of fluorescent reporters that may be molecularly targeted, enzyme-activated, or untargeted, vascular probes. Fluorescence guidance has substantially changed care strategies in numerous surgical fields; however, investigation and adoption in orthopaedic surgery have lagged. FGS shows the potential for improving patient care in orthopaedics via several applications including disease diagnosis, perfusion-based tissue healing capacity assessment, infection/tumor eradication, and anatomic structure identification. This review highlights current and future applications of fluorescence guidance in orthopaedics and identifies key challenges to translation and potential solutions.

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.

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.

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.

Shoulder Periprosthetic Joint Infection and All-Cause Mortality: A Worrisome Association

Background

Periprosthetic joint infection (PJI) can be a devastating complication following shoulder arthroplasty. PJI following hip and knee arthroplasties has been found to increase mortality. However, anatomical and bacteriologic differences could potentially result in a different trend after shoulder arthroplasties. Thus, the purpose of the present study was to determine whether there is an association between shoulder PJI and all-cause mortality.

Methods

Our institutional Total Joint Registry Database was queried to identify patients who underwent revision shoulder arthroplasty procedures between 2000 and 2018. A total of 1,160 procedures were then classified as either septic (21.8%) or aseptic (78.2%). Septic revisions were further subdivided into (1) debridement, antibiotics, irrigation, and implant retention (9.1%); (2) 2-stage reimplantation for deep infection (61.3%); (3) implant resection without reimplantation (3.6%); and (4) unexpected positive cultures at revision surgery (26.1%). The most common bacterium isolated was Cutibacterium acnes (64.4%). All-cause patient mortality was determined with use of our registry and confirmed with use of a nationwide mortality database. All-cause crude and adjusted mortality rates were then compared between groups.

Results

The 1-year crude mortality rate was 1.8% (95% confidence interval [CI], 0.9% to 2.6%) for the aseptic group and 2.8% (95% CI, 0.7% to 4.8%) for the septic group (p = 0.31). Multivariate Cox regression analysis demonstrated an elevated but statistically similar adjusted hazard ratio for 1-year all-cause mortality of 1.9 (95% CI, 0.8 to 4.6) when comparing the septic to the aseptic group (p = 0.17). The risk of 2-year all-cause mortality was significantly higher in the septic group, with a hazard ratio of 2.2 (95% CI, 1.1 to 4.5; p = 0.029). In univariate analyses, increased 5-year mortality in the septic revision group was associated with age, Charlson Comorbidity Index, and methicillin-resistant Staphylococcus aureus infection, whereas C. acnes infection was associated with lower mortality.

Conclusions

Shoulder PJI is associated with an adjusted 2-year all-cause mortality rate that is double that of aseptic patients. The results of the present study should be utilized to appropriately counsel patients who are considered to be at risk for infection following shoulder arthroplasty.

Level of Evidence

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Perioperative Clopidogrel (Plavix®) Continuation in Shoulder Arthroplasty: Approach Cautiously

Background

Methods

Results

Conclusion

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.

Patient outcomes after total hip arthroplasty in extreme elderly patients older than 80 years

BACKGROUND

While extreme elderly patients (age 80 and above) benefit from joint replacement, there is controversy about whether their physical function improves as much as younger individuals following total hip arthroplasty.

METHODS

We completed a retrospective cohort study comparing extreme elderly total hip arthroplasty (THA) patients to younger patients. We obtained data from a large institutional repository of 2327 consecutive THAs performed from April 2011 through July 2016 at an American academic medical centre. We performed multivariate regression analyses to determine associations 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, length of stay (LOS), and facility discharge.

RESULTS

There were 187 THAs (8.0%) in patients age ⩾ 80 years compared to 2140 THA procedures in patients < age 80. Extreme elderly patients had similar adjusted odds of achieving clinically significant PCS improvement after THA (p = 0.528) and there were no statistical differences in adjusted postoperative PCS score improvements between the cohorts. Extreme elderly patients were associated with a 0.68 day longer adjusted LOS (p < 0.001) and demonstrated higher adjusted odds of facility discharge following THA (OR 8.96, p < 0.001).

CONCLUSIONS

Compared to younger patients, extreme elderly individuals had similar adjusted postoperative functional outcomes following THA but utilised substantially more resources in the form of increased time in the hospital and higher rates of facility discharges.

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.

The Cost-Effectiveness of Reverse Total Shoulder Arthroplasty Versus Open Reduction Internal Fixation for Proximal Humerus Fractures in the Elderly

BACKGROUND

Open reduction and internal fixation (ORIF) of proximal humerus fractures in elderly individuals (age >70) carries a relatively high short-term complication and reoperation rate but is generally durable once healed. Reverse total shoulder arthroplasty (RTSA) for fractures may be associated with superior short-term quality of life but carries the lifelong liabilities of joint replacement. The tradeoff between short and long-term risks, coupled with disparities in quality of life and cost, makes this clinical decision amenable to cost-effectiveness analysis.

METHODS

A Markov state-transition model was constructed with a base case of a 75 year-old patient. Reoperation rates, quality of life values, mortality rates, and costs were based upon published literature. The model was run until all patients had died to simulate the accumulated costs and benefits.

RESULTS

RTSA was associated with greater quality of life (7.11 QALYs) than ORIF (6.22 QALYs). RTSA was cost-effective with an incremental cost-effectiveness ratio of $3,945/QALY and $27,299/ QALY from payor and hospital perspectives, respectively. RTSA was favored and cost-effective at any age above 65 and any Charlson Score. The model was sensitive to the utility of both procedures.

CONCLUSION

RTSA resulted in a higher quality of life and was cost-effective in comparison to ORIF for elderly patients.Level of Evidence: III.

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.

Preoperative Weight Loss for Morbidly Obese Patients Undergoing Total Knee Arthroplasty: Determining the Necessary Amount

BACKGROUND

Many surgeons require or request weight loss among morbidly obese patients (those with a body mass index [BMI] of ≥40 kg/m) before undergoing total knee arthroplasty. We sought to determine how much weight reduction was necessary to improve operative time, length of stay, discharge to a facility, and physical function improvement.

METHODS

Using a retrospective review of cohort data that were prospectively collected from 2011 to 2016 at 1 tertiary institution, we identified 203 patients who were morbidly obese at least 90 days before the surgical procedure and had their BMI measured again at the immediate preoperative visit. All heights and weights were clinically measured. We used logistic and linear regression models that adjusted for preoperative age, sex, year of the surgical procedure, bilateral status, physical function (Patient-Reported Outcomes Measurement Information System [PROMIS]-10 physical component score [PCS]), mental function (PROMIS-10 mental component score [MCS]), and the Charlson Comorbidity Index.

RESULTS

Of the 203 patients in the study, 41% lost at least 5 pounds (2.27 kg) before the surgical procedure, 29% lost at least 10 pounds (4.54 kg), and 14% lost at least 20 pounds (9.07 kg). Among morbidly obese patients, losing 20 pounds before a total knee arthroplasty was associated with lower adjusted odds of discharge to a facility (odds ratio [OR], 0.28 [95% confidence interval (CI), 0.09 to 0.94]; p = 0.039), lower odds of extended length of stay of at least 4 days (OR, 0.24 [95% CI, 0.07 to 0.88]; p = 0.031), and an absolute shorter length of stay (mean difference, -0.87 day [95% CI, -1.39 to -0.36 days]; p = 0.001). There were no differences in operative time or PCS improvement. Losing 5 or 10 pounds was not associated with differences in any outcome.

CONCLUSIONS

Losing at least 20 pounds before total knee arthroplasty was associated with shorter length of stay and lower odds of facility discharge for morbidly obese patients, even while most patients remained morbidly or severely obese. Although there were no differences in operative time or physical function improvement, this has considerable implications for patient burden and cost reduction. Patients and providers may want to focus on larger preoperative weight loss targets.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

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.

A comparison of radiographic leg-length and offset discrepancies between 2 intraoperative measurement techniques in anterior total hip arthroplasty

BACKGROUND

Anterior total hip arthroplasty (THA) allows the use of intraoperative fluoroscopy to assess leg-length and offset discrepancies. Two techniques to accomplish this are the transverse rod method and the radiographic overlay method. The aim of this study was to determine if they are equally effective options for minimizing postoperative radiologic discrepancies.

METHODS

We completed a retrospective cohort study comparing 106 anterior THAs from 1 surgeon using the transverse rod technique to 94 anterior THAs from another surgeon using the radiograph overlay technique. Radiographic leg-length discrepancy (LLD) and offset discrepancy (OD) were measured independently on postoperative radiographs. Parametric, nonparametric, and categorical statistical tests were used to compare LLD and OD between groups.

RESULTS

Baseline characteristics were similar between groups. The mean LLD of 4.8 mm in the radiograph overlay group was not significantly different from the 4.4 mm mean discrepancy in the transverse rod group (P = .424), and the rates of LLD < 5 mm and LLD < 10 mm were not significantly different (P = .772, P = .179). The mean OD of 5.1 mm in the radiograph overlay group was not significantly different from the 4.8 mm mean discrepancy in the transverse rod group (P = .668), and there was no significant difference in the rates of OD < 5 mm and OD < 10 mm (P = .488, P = .878).

CONCLUSIONS

There was no difference between the measured LLD and OD by the 2 surgeons, suggesting that the techniques are equally effective options.

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.

A Collision Tumor Involving a Primary Leiomyosarcoma of the Lower Extremity and a Metastatic Medullary Thyroid Carcinoma: A Case Report

CASE

A 49-year-old man presented with a rapidly growing thigh mass. Histologic analyses demonstrated separate regions that were consistent with a collision tumor composed of a primary leiomyosarcoma and a metastatic medullary thyroid carcinoma. After responding to chemotherapy, the patient underwent resection of the tumor and a total thyroidectomy; he was disease-free 9 years after the diagnosis.

CONCLUSION

A wide diagnostic differential and thorough histologic analysis are necessary in patients presenting with neoplasms of the extremities. A leiomyosarcoma may be a hospitable location for metastatic disease, and the presence of a collision tumor should be considered when pathology findings are equivocal.

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.

A novel epileptic encephalopathy mutation in KCNB1 disrupts Kv2.1 ion selectivity, expression, and localization

A missense mutation in the pore-forming α subunit of a delayed rectifier Kv channel is associated with epileptic encephalopathy, alters the cation selectivity of voltage-gated currents, and disrupts channel expression and localization.

The epileptic encephalopathies are a group of highly heterogeneous genetic disorders. The majority of disease-causing mutations alter genes encoding voltage-gated ion channels, neurotransmitter receptors, or synaptic proteins. We have identified a novel de novo pathogenic K⁺ channel variant in an idiopathic epileptic encephalopathy family. Here, we report the effects of this mutation on channel function and heterologous expression in cell lines. We present a case report of infantile epileptic encephalopathy in a young girl, and trio-exome sequencing to determine the genetic etiology of her disorder. The patient was heterozygous for a de novo missense variant in the coding region of the KCNB1 gene, c.1133T>C. The variant encodes a V378A mutation in the α subunit of the Kv2.1 voltage-gated K⁺ channel, which is expressed at high levels in central neurons and is an important regulator of neuronal excitability. We found that expression of the V378A variant results in voltage-activated currents that are sensitive to the selective Kv2 channel blocker guangxitoxin-1E. These voltage-activated Kv2.1 V378A currents were nonselective among monovalent cations. Striking cell background–dependent differences in expression and subcellular localization of the V378A mutation were observed in heterologous cells. Further, coexpression of V378A subunits and wild-type Kv2.1 subunits reciprocally affects their respective trafficking characteristics. A recent study reported epileptic encephalopathy-linked missense variants that render Kv2.1 a tonically activated, nonselective cation channel that is not voltage activated. Our findings strengthen the correlation between mutations that result in loss of Kv2.1 ion selectivity and development of epileptic encephalopathy. However, the strong voltage sensitivity of currents from the V378A mutant indicates that the loss of voltage-sensitive gating seen in all other reported disease mutants is not required for an epileptic encephalopathy phenotype. In addition to electrophysiological differences, we suggest that defects in expression and subcellular localization of Kv2.1 V378A channels could contribute to the pathophysiology of this KCNB1 variant.

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 β 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.

Saline-coupled bipolar sealing in simultaneous bilateral total knee arthroplasty

Background

The efficacy of saline-coupled bipolar sealing devices in joint arthroplasty is uncertain, and the utility in simultaneous bilateral total knee arthroplasty (TKA) has not been reported.

Methods

This study compares the use of bipolar sealing and conventional electrocautery in 71 consecutive patients. The experimental and control groups were matched for age, sex, body mass index, American Society of Anesthesiologists (ASA) classification, and preoperative hemoglobin. Variables of interest included blood loss, transfusion requirements, and operative characteristics.

Results

In comparison to patients treated with conventional electrocautery, those treated with the bipolar sealer were 35% less likely to require transfusion. The median number of transfusions per case was also significantly lower in the experimental group. Hemoglobin change, total blood loss, and length of stay were not significantly different between the groups. The experimental group had longer operative times.

Conclusions

Bipolar sealing shows promise as a blood loss reduction tool in simultaneous bilateral TKA. The marginal savings attributed to reduced transfusion rates with use of the bipolar sealer did not exceed the additional per-case expense of using the device. The decision to use the device with the goal of less blood loss must come with the additional expense associated with its use.

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.

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.

Antibody-guided photoablation of voltage-gated potassium currents

A family of 40 mammalian voltage-gated potassium (Kv) channels control membrane excitability in electrically excitable cells. The contribution of individual Kv channel types to electrophysiological signaling has been difficult to assign, as few selective inhibitors exist for individual Kv subunits. Guided by the exquisite selectivity of immune system interactions, we find potential for antibody conjugates as selective Kv inhibitors. Here, functionally benign anti-Kv channel monoclonal antibodies (mAbs) were chemically modified to facilitate photoablation of K currents. Antibodies were conjugated to porphyrin compounds that upon photostimulation inflict localized oxidative damage. Anti-Kv4.2 mAb–porphyrin conjugates facilitated photoablation of Kv4.2 currents. The degree of K current ablation was dependent on photon dose and conjugate concentration. Kv channel photoablation was selective for Kv4.2 over Kv4.3 or Kv2.1, yielding specificity not present in existing neurotoxins or other Kv channel inhibitors. We conclude that antibody–porphyrin conjugates are capable of selective photoablation of Kv currents. These findings demonstrate that subtype-specific mAbs that in themselves do not modulate ion channel function are capable of delivering functional payloads to specific ion channel targets.

Lumbar discectomy--percentage of disc removal and detection of anterior annulus perforation

A prospective study was carried out to estimate the percentage of disc removal at the time of lumbar laminectomy and discectomy. Intraoperative discograms were obtained which afforded a method of calculating the percentage of disc removal. The technique permits localization of the level of discectomy and provides a means of detecting anterior annulus perforation intraoperatively, which we hope will reduce the morbidity of anterior annulus perforation. A comparison between the efficacy of disc removal (microdiscectomy vs. laminectomy) is also presented.