Medicare's Post-Acute Care Reimbursement Models as of 2023: Past, Present, and Future

The Centers for Medicare & Medicaid Services is continually working to mitigate unnecessary expenditures, particularly in post-acute care (PAC). Medicare reimburses for orthopaedic surgeon services in varied models, including fee-for-service, bundled payments, and merit-based incentive payment systems. The goal of these models is to improve the quality of care, reduce health-care costs, and encourage providers to adopt innovative and efficient health-care practices. This article delves into the implications of each payment model for the field of orthopaedic surgery, highlighting their unique features, incentives, and potential impact in the PAC setting. By considering the historical, current, and future Medicare reimbursement models, we hope to provide an understanding of the optimal payment model based on the specific needs of patients and providers in the PAC setting.

High Area Deprivation Index is Associated With Not Achieving the Patient-acceptable Symptom State After TKA

BACKGROUND

The Area Deprivation Index (ADI) approximates a patient's relative socioeconomic deprivation. The ADI has been associated with increased healthcare use after TKA, but it is unknown whether there is an association with patient-reported outcome measures (PROMs). Given that a high proportion of patients are dissatisfied with their results after TKA, and the large number of these procedures performed, knowledge of factors associated with PROMs may indicate opportunities to provide support to patients who might benefit from it.

QUESTIONS/PURPOSES

(1) Is the ADI associated with achieving the minimum clinically important difference (MCID) for the Knee Injury and Osteoarthritis Outcome Score (KOOS) for pain, Joint Replacement (JR), and Physical Function (PS) short forms after TKA? (2) Is the ADI associated with achieving the patient-acceptable symptom state (PASS) thresholds for the KOOS pain, JR, and PS short forms?

METHODS

This was a retrospective study of data drawn from a longitudinally maintained database. Between January 2016 and July 2021, a total of 12,239 patients underwent unilateral TKA at a tertiary healthcare center. Of these, 92% (11,213) had available baseline PROM data and were potentially eligible. An additional 21% (2400) of patients were lost before the minimum study follow-up of 1 year or had incomplete data, leaving 79% (8813) for analysis here. The MCID is the smallest change in an outcome score that a patient is likely to perceive as a clinically important improvement, and the PASS refers to the threshold beyond which patients consider their symptoms acceptable and consistent with adequate functioning and well-being. MCIDs were calculated using a distribution-based method. Multivariable logistic regression models were created to investigate the association of ADI with 1-year PROMs while controlling for patient demographic variables. ADI was stratified into quintiles based on their distribution in our sample. Achievement of MCID and PASS thresholds was determined by the improvement between preoperative and 1-year PROMs.

RESULTS

After controlling for patient demographic factors, ADI was not associated with an inability to achieve the MCID for the KOOS pain, KOOS PS, or KOOS JR. A higher ADI was independently associated with an increased risk of inability to achieve the PASS for KOOS pain (for example, the odds ratio of those in the ADI category of 83 to 100 compared with those in the 1 to 32 category was 1.34 [95% confidence interval 1.13 to 1.58]) and KOOS JR (for example, the OR of those in the ADI category of 83 to 100 compared with those in the 1 the 32 category was 1.29 [95% CI 1.10 to 1.53]), but not KOOS PS (for example, the OR of those in the ADI category of 83 to 100 compared with those in the 1 the 32 category was 1.09 [95% CI 0.92 to 1.29]).

CONCLUSION

Our findings suggest that social and economic factors are associated with patients' perceptions of their overall pain and function after TKA, but such factors are not associated with patients' perceptions of their improvement in symptoms. Patients from areas with higher deprivation may be an at-risk population and could benefit from targeted interventions to improve their perception of their healthcare experience, such as through referrals to nonemergent medical transportation and supporting applications to local care coordination services before proceeding with TKA. Future research should investigate the mechanisms underlying why socioeconomic disadvantage is associated with inability to achieve the PASS, but not the MCID, after TKA.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Patient satisfaction and patient-reported outcomes do not vary by BMI class in total hip arthroplasty

PURPOSE

Obesity has been identified as a risk factor for postoperative complications in patients undergoing total hip arthroplasty (THA). This study aimed to investigate patient-reported outcomes, pain, and satisfaction as a function of body mass index (BMI) class in patients undergoing THA.

METHODS

1736 patients within a prospective observational study were categorized into BMI classes. Pre- and postoperative Hip disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS JR), satisfaction, and pain scores were compared by BMI class using one-way ANOVA.

RESULTS

Healthy weight patients reported the highest preoperative HOOS JR (56.66 ± 13.35) compared to 45.51 ± 14.45 in Class III subjects. Healthy weight and Class III patients reported the lowest (5.65 ± 2.01) and highest (7.06 ± 1.98, p < 0.0001) preoperative pain, respectively. Changes in HOOS JR scores from baseline suggest larger improvements with increasing BMI class, where Class III patients reported an increase of 33.7 ± 15.6 points at 90 days compared to 26.1 ± 17.1 in healthy weight individuals (p = 0.002). Fewer healthy weight patients achieved the minimal clinically important difference (87.4%) for HOOS JR compared to Class II (96.5%) and III (94.7%) obesity groups at 90 days postoperatively. Changes in satisfaction and pain scores were largest in the Class III patients. Overall, no functional outcomes varied by BMI class postoperatively.

CONCLUSION

Patients of higher BMI class reported greater improvements following THA. While risk/benefit shared decision-making remains a personalized requirement of THA, this study highlights that utilization of BMI cutoff may not be warranted based on pain and functional improvement.

Trends in prevalence and complications for smokers who underwent total hip arthroplasty from 2011 to 2019: an analysis of 243,163 patients

BACKGROUND

Smoking is an established risk factor for postoperative complications after total hip arthroplasty (THA). It is unknown if the decreasing prevalence of adult smoking in the United States is reflected in the elective THA patient population. We aimed to investigate recent trends in: (1) the prevalence of smoking pre-THA, stratified by patient demographics; and (2) rates of 30-day complications and increased healthcare utilisation post-THA in smokers versus non-smokers.

METHODS

Patients who underwent primary elective THA (2011-2019) were identified using the National Surgical Quality Improvement Program database. A total of 243,163 cases (Smokers: n = 30,536; Non-smokers: n = 212,627) were included. Trends analyses were performed for smoking prevalence across the study period. Smokers were propensity score-matched (1:1) to a cohort of non-smokers (n = 29,628, each), and rates of 30-day complications, readmission, and non-home discharge were compared.

RESULTS

The rate of preoperative smoking significantly decreased from 14.0% in 2011 to 11.6% in 2019 (p-trend = 0.0286). When stratified, a significant decreasing trend in smoking was found for males and all races; within races, American-Indian/Alaska-Native race had the sharpest decline (2011:36.3% vs. 2019:23.2%). No significant change in 30-day complication rates among smokers or non-smokers was observed (p-trend > 0.05), but non-home discharge significantly decreased for both smokers (p-trend = 0.001) and non-smokers (p-trend < 0.001). After matching, higher rates of superficial surgical site infections (SSI) (0.9% vs. 0.5%; p < 0.001), deep SSI (0.5% vs. 0.3%; p < 0.001), wound disruption (0.2% vs. 0.1%; p = 0.006), and readmission (4.2% vs. 3.1%; p = <0.001) were found in smokers versus non-smokers.

CONCLUSIONS

The present study is encouraging that national efforts to reduce the prevalence of smoking may be successful within the THA population, but there is a persistently elevated risk of postoperative complications in smokers after THA.

Cannabis Use Following Total Joint Arthroplasty is Associated With Increased Risks? A Meta-Analysis

BACKGROUND

With the increased legalization of cannabis, a new unknown emerges for orthopaedic surgeons and their patients. This systematic review aimed to (1) evaluate complications of cannabis use; (2) determine the effects of cannabis on pain and opioid consumption; and (3) evaluate healthcare utilizations associated with cannabis use among patients undergoing total joint arthroplasty (TJA).

METHODS

A systematic review was performed. A search of the literature was performed in 5 databases. We included studies between January 2012 and July 2022 reporting cannabis use and complications, pain management, opioid consumption, length of stay, costs, or functional outcomes following TJA. A meta-analysis of odds ratios (ORs) and continuous variables was performed. A total of 19 articles were included in our final analysis.

RESULTS

Cannabis use was associated with higher odds for deep vein thrombosis (DVT) (OR: 1.46, 95% Confidence Interval [CI]: 1.13 to 1.89) and revisions (OR: 1.47 [95% CI: 1.41 to 1.53]) in total knee arthroplasty (TKA). Cannabis use was associated with similar odds for DVT in total hip arthroplasty (THA) (OR: 1.30 [95% CI: 0.79 to 2.13]), pulmonary embolus in both TKA (OR: 1.29 [95% CI: 0.95 to 1.77]), THA (OR: 0.55 [95% CI: 0.09 to 3.28]), and cardiovascular complications in TKA (OR: 1.97 [95% Cl: 0.93 to 4.14]). Cannabis use did not alter pain scores, opioid consumption, or cost of care in THA (estimate: $2,550.51 [95% CI: $356.58 to $5,457.62]) but was associated with higher costs in TKA (estimate: $3,552.46 [95% CI: $1,729.71 to $5,375.22]). There was no difference in lengths of stay or functional outcomes; however, there may be a potentially increased risk for prosthetic complications, pneumonia, and cerebrovascular accidents among cannabis users.

CONCLUSION

Cannabis use may be associated with an increased risk of DVTs, revisions, pneumonia, cerebrovascular accidents, and cardiac complications after TJA. Higher-level studies are needed to ascertain the impact of cannabis use for patients undergoing TJA.

A Longitudinal Analysis of Weight Changes before and after Total Knee Arthroplasty: Weight Trends, Patterns, and Predictors

Longitudinal data on patient trends in body mass index (BMI) and the proportion that gains or loses significant weight before and after total knee arthroplasty (TKA) are scarce. This study aimed to observe patients longitudinally for a 2-year period and determine (1) clinically significant BMI changes during the 1 year before and 1 year after TKA and (2) identify factors associated with clinically significant weight changes.A prospective cohort of 5,388 patients who underwent primary TKA at a tertiary health care institution between January 2016 and December 2019 was analyzed. The outcome of interests was clinically significant weight changes, defined as a ≥5% change in BMI, during the 1-year preoperative and postoperative periods, respectively. Patient-specific variables and demographics were assessed as potential predictors of weight change using multinomial logistic regression.Overall, 47% had a stable weight throughout the study period (preoperative: 17% gained, 15% lost weight; postoperative: 19% gained, 16% lost weight). Patients who were older (odds ratio [OR] = 0.95), men (OR = 0.47), overweight (OR = 0.36), and Obese Class III (OR = 0.06) were less likely to gain weight preoperatively. Preoperative weight loss was associated with postoperative weight gain 1 year after TKA (OR = 3.03). Preoperative weight gain was associated with postoperative weight loss 1 year after TKA (OR = 3.16).Most patients maintained a stable weight before and after TKA. Weight changes during the 1 year before TKA were strongly associated with reciprocal rebounds in BMI postoperatively, emphasizing the importance of ongoing weight management during TKA and the recognition of patients at higher risk for weight gain.Level of evidence II (prospective cohort study).

Establishing patient-centered metrics for the knee injury and osteoarthritis outcome score following medial unicompartmental knee arthropalsty

BACKGROUND

This study aimed to determine the minimal clinically important difference (MCID) and the patient acceptable symptoms state (PASS) threshold for the knee injury and osteoarthritis outcome score (KOOS) pain subscore, KOOS physical short form (PS), and KOOS joint replacement (JR) following medial unicompartmental knee arthroplasty (mUKA).

METHODS

Prospectively collected data from 743 patients undergoing mUKA from a single academic institution from April 2015 through March 2020 were analyzed. Patient-reported outcome measures (PROMs) were collected both pre-operatively and 1-year post-operatively. Distribution-based and anchored-based approaches were used to estimate MCIDs and PASS, respectively. The optimal cut-off point and the percentage of patients who achieved PASS were also calculated.

RESULTS

MCID for KOOS-pain, KOOS-PS, and KOOS-JR following mUKA were calculated to be 7.6, 7.3, and 6.2, respectively. The PASS threshold for KOOS pain, PS, and JR were 77.8, 70.3, and 70.7, with 68%, 66%, and 64% of patients achieving satisfactory outcomes, respectively. Cut-off values for delta KOOS pain, PS, and JR were found to be 25.7, 14.3, and 20.7 with 73%, 69%, and 68% of patients achieving satisfactory outcomes, respectively.

CONCLUSION

The current study identified useful values for the MCID and PASS thresholds at 1 year following medial UKA of KOOS pain, KOOS PS, and KOOS JR scores. These values may be used as targets for surgeons when evaluating PROMS using KOOS to determine whether patients have achieved successful outcomes after their surgical intervention. Potential uses include the integration of these values into predictive models to enhance shared decision-making and guide more informed decisions to optimize patient outcomes.

LEVEL OF EVIDENCE

III.

Return to Sports and Return to Work After Total Hip Arthroplasty: A Systematic Review and Meta-analysis

BACKGROUND

Return to work (RTW) and sports (RTS) are critical gauges to improvement among patients after total hip arthroplasty (THA). This study aimed to determine rates, timelines, and prognostic factors associated with RTW and RTS outcomes after primary THA.

METHODS

A systematic review was conducted on MEDLINE, EMBASE, and CENTRAL databases with 57 studies meeting inclusion/exclusion criteria. The risk of bias was assessed using the Risk of Bias in Non-randomized Studies of Interventions and risk of bias in randomized trials (RoB2) tools. Meta-analysis and pooled analysis were conducted, with forest plots to summarize odds ratios and 95% confidence interval (CI).

RESULTS

The pooled RTW rate across all studies was 70% (95% CI, 68%-80%), with rates varying significantly from 11% to 100%. The mean time to RTW was 11.2 weeks (range 1-27). A time point analysis showed increasing RTW rates with a maximum rate at 2 years of 90%. Increased age (p < 0.001) and preoperative heavy labor (p = 0.005) were associated with lower RTW rates. The RTS rate ranged from 42% to 100%, with a pooled rate of 85% (95% CI, 74%-92%). The mean time to RTS was 16.1 weeks (range 8-26). The RTS ranged from 20% to 80% with a pooled proportion of 56% (95% CI, 42%-70%, I2 = 90%) for high-intensity sports and from 75% to 100% for low-intensity sports with a pooled proportion of 97% (95% CI, 83-99, I2 = 93%).

CONCLUSION

Most patients RTW and RTS after THA in an increasing manner as time passes with rates more than 85% after 1 year. These rates may be greatly affected by various factors, most notably age, the intensity of the sport, and the type of work performed. In general, young patients, low-demand work or sports can be resumed as soon as 4 to 6 weeks after surgery, but with increased restrictions as the intensity increases. This information should be used by practitioners to manage postoperative expectations and provide appropriate recommendations to patients.

LEVEL OF EVIDENCE

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

Preoperative Veteran RAND-12 Mental Composite Score of >60 Associated With Increased Likelihood of Patient Satisfaction After Total Hip Arthroplasty

BACKGROUND

The present study aimed to determine the distribution of Veterans RAND 12-Item health survey (VR-12) mental component scores (MCS) of patients undergoing primary total hip arthroplasty (THA) and the thresholds of VR-12 MCS scores that predict higher health care utilizations and 1-year patient-reported outcome measures (PROMs).

METHODS

A prospective cohort of 4,194 primary THA patients (January 2016 to December 2019) were included. Multivariable and cubic spline regression models were used to test for associations between preoperative VR-12 MCS and postoperative outcomes, including: 90-day hospital resource utilization (nonhome discharge, prolonged length of stay [LOS](ie, ≥3 days), all-cause readmission), attainment of patient acceptable symptom state (PASS) at 1-year postoperative and substantial clinical benefit (SCB) in the hip disability osteoarthritis outcome score (HOOS)-pain and HOOS-physical short form.

RESULTS

Lower VR-12 MCS was associated with older age, obesity, Black race, women, and smokers (all P < .001). Preoperative VR-12 MCS<20 was associated with more than twice the odds of nonhome discharge (odds ratio [OR]:2.31) and prolonged LOS (OR: 3.46). VR-12 MCS >60 was associated with higher odds of achieving PASS (OR: 2.00) and SCB in HOOS-joint related (JR) (OR: 1.16). Starting VR-12 MCS ≤40, there were exponentially higher odds of worse outcomes.

CONCLUSION

Low preoperative VR-12 MCS, specifically less than 40, may predict increased health care utilization. Furthermore, preoperative VR-12 MCS>60 predicts greater satisfaction at 1 year and higher odds of achieving SCB in HOOS-JR. Quantifiable thresholds for VR-12 MCS may aid in shared decision-making and patient counseling in setting expectations or may guide specific care pathway interventions to address mental health during THA.

LEVEL OF EVIDENCE

II.

Hip Abductor Reconstruction with the Use of Mesh and Distal Cerclage Cable Fixation: A Case Report and Surgical Technique

CASE

This is a case of a 71-year-old female patient with recurrent instability and complex hip abductor deficiency after total hip arthroplasty (THA) who was treated successfully with an abductor reconstruction with gluteal transfer with mesh reconstruction. The patient returned to nonassisted ambulation with no further THA dislocations at the 1-year follow-up.

CONCLUSION

Abductor deficiencies after THA are complex and have a high potential for long-term disability if not properly diagnosed and treated. A modified gluteal transfer with mesh reconstruction and distal fixation with cerclage cable allowed for sustained restoration of functional hip abduction and stability after revision THA.

Do patient-reported outcome measures improve after aseptic revision total hip arthroplasty?

BACKGROUND

The purpose of this study was to determine patient-reported outcome measures (PROMs) changes in: (1) pain, function and global health; and (2) predictors of PROMs in patients undergoing aseptic revision total hip arthroplasty (rTHA) using a multilevel model with patients nested within surgeon.

METHODS

A prospective cohort of 216 patients with baseline and 1-year PROMs who underwent aseptic rTHA between January 2016 and December 2017 were analysed. The most common indication for rTHA was aseptic loosening, instability, and implant failure. The PROMs included in this study were HOOS Pain and HOOS Physical Function Short-form (PS), Veterans RAND-12 Physical Component Score (VR-12 PCS), and VR-12 Mental Component Score (MCS). Multivariable linear regression models were constructed for predicting 1-year PROMs.

RESULTS

Mean 1-year PROMs improvement for aseptic revisions were 30.4 points for HOOS Pain and 22.1 points for HOOS PS. Predictors of better pain relief were patients with higher baseline pain scores. Predictors of better 1-year function were patients with higher baseline function and patients with a posterolateral hip surgical approach during revision. Although VR-12 PCS scores had an overall improvement, nearly 50% of patients saw no improvement or had worse physical component scores. Only 30.7% of patients reported improvements in VR-12 MCS.

CONCLUSIONS

Overall, patients undergoing aseptic rTHA improved in pain and function PROMs at 1 year. Although global health assessment improved overall, nearly half of aseptic rTHA patients reported no change in physical/mental health status. The associations highlighted in this study can help guide the shared decision-making process by setting expectations before aseptic revision THA.

Robotic Arm-Assisted versus Manual Total Knee Arthroplasty: A Propensity Score-Matched Analysis

The purpose of this study was to compare (1) operative time, (2) in-hospital pain scores, (3) opioid medication use, (4) length of stay (LOS), (5) discharge disposition at 90-day postoperative, (6) range of motion (ROM), (7) number of physical therapy (PT) visits, (8) emergency department (ED) visits, (9) readmissions, (10) reoperations, (11) complications, and (12) 1-year patient-reported outcome measures (PROMs) in propensity matched patient cohorts who underwent robotic arm-assisted (RA) versus manual total knee arthroplasty (TKA). Using a prospectively collected institutional database, patients who underwent RA- and manual TKA were the nearest neighbor propensity score matched 3:1 (255 manual TKA:85 RA-TKA), accounting for various preoperative characteristics. Data were compared using analysis of variance (ANOVA), Kruskal-Wallis, Pearson's Chi-squared, and Fisher's exact tests, when appropriate. Postoperative pain scores, opioid use, ED visits, readmissions, and 1-year PROMs were similar between the cohorts. Manual TKA patients achieved higher maximum flexion ROM (120.3 ± 9.9 versus 117.8 ± 10.2, p = 0.043) with no statistical differences in other ROM parameters. Manual TKA had shorter operative time (105 vs.113 minutes, p < 0.001), and fewer PT visits (median [interquartile range] = 10.0 [8.0-13.0] vs. 11.5 [9.5-15.5] visits, p = 0.014). RA-TKA had shorter LOS (0.48 ± 0.59 vs.1.2 ± 0.59 days, p < 0.001) and higher proportion of home discharges (p < 0.001). RA-TKA and manual TKA had similar postoperative complications and 1-year PROMs. Although RA-TKA patients had longer operative times, they had shorter LOS and higher propensity for home discharge. In an era of value-based care models and the steady shift to outpatient TKA, these trends need to be explored further. Long-term and randomized controlled studies may help determine potential added value of RA-TKA versus manual TKA. This study reflects level of evidence III.

Neighborhood Socioeconomic Disadvantage Associated With Increased Healthcare Utilization After Total Hip Arthroplasty

BACKGROUND

The multifaceted effects of socioeconomic status on healthcare outcomes can be difficult to quantify. The Area Deprivation Index (ADI) quantifies a socioeconomic disadvantage with higher scores indicating more disadvantaged groups. The present study aimed to describe the ADI distribution for primary total hip arthroplasty (THA) patients stratified by patient demographics and to characterize the association of ADI with healthcare utilization (discharge disposition and length of stay [LOS]), 90-day emergency department (ED) visits, and 90-day all cause readmissions.

METHODS

Two thousand three hundred and ninety one patients who underwent primary elective THA over a 13-month period were included. A multivariable binary logistic regression analysis with outcomes of nonhome discharge, prolonged LOS (>3 days), 90-day ED visits, and 90-day readmission were performed using predictors of ADI, gender, race, smoking status, body mass index, insurance status, and Charlson comorbidity index. Plots of restricted cubic splines were used to graph associations between ADI as a continuous variable and the outcomes of interest using odds ratios.

RESULTS

In the multivariable regression model, there were statistically significant higher odds of nonhome discharge (OR, 1.82; 95% CI, 1.19-2.77, P = .005) for individuals in the 61-80 ADI quintile as compared to the reference group of 21-40. Individuals in the highest ADI quintile, 81-100, had the greatest odds of nonhome discharge (OR, 2.20; 95% CI, 1.39-3.49, P < .001) and prolonged LOS (OR, 1.91, 95% CI, 1.28-2.84, P = .001).

CONCLUSIONS

Higher ADI is associated with an increased healthcare utilization within 90 days of THA.

No clinically meaningful difference in 1-year patient-reported outcomes among major approaches for primary total hip arthroplasty

BACKGROUND

Debate continues around the most effective surgical approach for primary total hip arthroplasty (THA). This study's purpose was to compare 1-year patient-reported outcome measures (PROMs) of patients who underwent direct anterior (DA), transgluteal anterolateral (AL)/direct lateral (DL), and posterolateral (PL) approaches.

METHODS

A prospective consecutive series of primary THA for osteoarthritis (n = 2390) were performed at 5 sites within a single institution with standardised care pathways (20 surgeons). Patients were categorised by approach: DA (n = 913; 38%), AL/DL (n = 505; 21%), or PL (n = 972; 41%). Primary outcomes were pain, function, and activity assessed by 1-year postoperative PROMs. Multivariable regression modeling was used to control for differences among the groups. Wald tests were performed to test the significance of select patient factors and simultaneous 95% confidence intervals were constructed.

RESULTS

At 1-year postoperative, PROMs were successfully collected from 1842 (77.1%) patients. Approach was a statistically significant factor for 1-year HOOS pain (p = 0.002). Approach was not a significant factor for 1-year HOOS-PS (p = 0.16) or 1-year UCLA activity (p = 0.382). Pairwise comparisons showed no significant difference in 1-year HOOS pain scores between DA and PL approach (p > 0.05). AL/DL approach had lower (worse) pain scores than DA or PL approaches with differences in adjusted median score of 3.47 and 2.43, respectively (p < 0.05).

CONCLUSIONS

Patients receiving the AL/DL approach had a small statistical difference in pain scores at 1 year, but no clinically meaningful differences in pain, activity, or function exist at 1-year postoperative.

Improved accuracy and fewer outliers with a novel CT-free robotic THA system in matched-pair analysis with manual THA

Accurate component orientation and restoration of hip biomechanics remains a continuing challenge in total hip arthroplasty (THA). The goal of this study was to analyze the accuracy/reproducibility of a novel CT-free and pin-less robotic-assisted THA (RA-THA) platform compared to manual THA (mTHA). This matched-pair cadaveric study compared this RA-THA system to mTHA (n = 33/arm), both using the assistance of fluoroscopic imaging, in a group of 14 high-volume arthroplasty surgeons. In both groups, surgeons were asked to aim for 40°/15° for cup inclination/version, and 0 mm of leg length discrepancy (LLD). A validated and accurate method using radio-opaque markers measured cup inclination/version and LLD. The accuracy and reproducibility (fewer outliers) of cup inclination was significantly improved in the robotic group (1.8° ± 1.3° vs 6.4° ± 4.9°, respectively, robotic vs manual; p < 0.001), with no significant difference between groups for version. The reproducibility of LLD was significantly improved in the robotic group (p = 0.003). For all parameters studied, the robotic group had an improved accuracy and lower variance (fewer outliers). The percentage of cases within the more restrictive Callanan safe zone was 100% for RA-THA vs 73% for mTHA (p = 0.002). The CT-free RA-THA platform, using only fluoroscopic imaging, demonstrated more accurate acetabular cup positioning, when compared to the mTHA procedures performed by high-volume hip surgeons (naive to this RA-THA platform), with respect to cup inclination and placement within the Lewinnek/Callanan safe zones. Future study must incorporate economic factors, lower volume surgeons, clinical and patient-centric outcomes, and other radiographic parameters in controlled studies in large sample sizes.

Should an Age Cutoff Be Considered for Elective Total Knee Arthroplasty Patients? An Analysis of Operative Success Based on Patient-Reported Outcomes

Total knee arthroplasty (TKA) is increasing in the elderly population; however, some patients, family members, and surgeons raise age-related concerns over expected improvement and risks. This study aimed to (1) evaluate the relationship between age and change in patient-reported outcome measures (PROMs); (2) model how many patients would be denied improvements in PROMs if hypothetical age cutoffs were implemented; and (3) assess length of stay (LOS), readmission, reoperation, and mortality per age group. A prospective cohort of 4,396 primary TKAs (August 2015-August 2018) was analyzed. One-year PROMs were evaluated via Knee injury and Osteoarthritis Outcome Score (KOOS)-pain, -physical function short form (-PS), and -quality of life (-QOL), as well as Veterans Rand-12 (VR-12) physical (-PCS) and mental component (-MCS) scores. Positive predictive values (PPVs) of the number of postoperative "failures" (i.e., unattained minimal clinically important difference in PROMs) relative to number of hypothetically denied "successes" from a theoretical age-group restriction was estimated. KOOS-PS and QOL median score improvements were equivalent among all age groups (p = 0.946 and p = 0.467, respectively). KOOS-pain improvement was equivalent for ≥80 and 60-69-year groups (44.4 [27.8-55.6]). Median VR-12 PCS improvements diminished as age increased (15.9, 14.8, and 13.4 for the 60-69, 70-79, and ≥80 groups, respectively; p = 0.002) while improvement in VR-12 MCS was similar among age groups (p = 0.440). PPV for failure was highest in the ≥80 group, yet remained <34% for all KOOS measures. Overall mortality was highest in the ≥80 group (2.14%, n = 9). LOS >2, non-home discharge, and 90-day readmission were highest in the ≥80 group (8.11% [n = 24], p < 0.001; 33.7% [n = 109], p < 0.001; and 34.4% [n = 111], p = 0.001, respectively). Elderly patients exhibited similar improvement in PROMs to younger counterparts despite higher LOS, non-home discharge, and 90-day readmission. Therefore, special care pathways should be implemented for those age groups.

Recurrent Hemarthrosis Secondary to Erosive Patellofemoral Arthritis Treated with Arthroplasty: A Report of 3 Cases

CASE

Three patients presented with recurrent hemarthrosis secondary to erosive patellofemoral arthritis. Recurrent hemarthrosis from the eroded patellofemoral subchondral bone has not been well described. Each patient presented with symptoms secondary to painful effusions that were identified by aspiration. Each patient was successfully treated with patellofemoral or total knee arthroplasty.

CONCLUSION

Spontaneous or recurrent effusions in the setting of erosive patellofemoral arthritis should prompt orthopaedic surgeons to consider hemarthrosis as the cause of such effusions. Patellofemoral or total knee arthroplasty is effective in resolving the hemarthroses, resolving pain, and restoring function in these patients.

Similar Healthcare Utilization and 1-Year Patient-Reported Outcomes between Cemented and Cementless Primary Total Knee Arthroplasty: A Propensity Score-Matched Analysis

Cementless fixation for total knee arthroplasty (TKA) has gained traction with the advent of newer fixation technologies. This study assessed (1) healthcare utilization (length of stay (LOS), nonhome discharge, 90-day readmission, and 1-year reoperation); (2) 1-year mortality; and (3) 1-year joint-specific and global health-related patient-reported outcome measures (PROMs) among patients who received cementless versus cemented TKA. Patients who underwent cementless and cemented TKA at a single institution (July 2015-August 2018) were prospectively enrolled. A total of 424 cementless and 5,274 cemented TKAs were included. The cementless cohort was propensity score-matched to a group cemented TKAs (1:3-cementless: n = 424; cemented: n = 1,272). Within the matched cohorts, 76.9% (n = 326) cementless and 75.9% (n = 966) cementless TKAs completed 1-year PROMs. Healthcare utilization measures, mortality and the median 1-year change in knee injury and osteoarthritis outcome score (KOOS)-pain, KOOS-physical function short form (PS), KOOS-knee related quality of life (KRQOL), Veteran Rand (VR)-12 mental composite (MCS), and physical composite (PCS) scores were compared. The minimal clinically important difference (MCID) for PROMs was calculated. Cementless TKA exhibited similar rates of median LOS (p = 0.109), nonhome discharge disposition (p = 0.056), all-cause 90-day readmission (p = 0.226), 1-year reoperation (p = 0.597), and 1-year mortality (p = 0.861) when compared with cemented TKA. There was no significant difference in the median 1-year improvement in KOOS-pain (p = 0.370), KOOS-PS (p = 0.417), KOOS-KRQOL (p = 0.101), VR-12-PCS (p = 0.269), and VR-12-MCS (p = 0.191) between the cementless and cemented TKA cohorts. Rates of attaining MCID were similar in both cohorts for assessed PROMs (p > 0.05, each) except KOOS-KRQOL (cementless: n = 313 (96.0%) vs. cemented: n = 895 [92.7%]; p = 0.036). Cementless TKA provides similar healthcare-utilization, mortality, and 1-year PROM improvement versus cemented TKA. Cementless fixation in TKA may provide value through higher MCID improvement in quality of life. Future episode-of-care cost-analyses and longer-term survivorship investigations are warranted.

The Potential Effects of Imposing a Body Mass Index Threshold on Patient-Reported Outcomes After Total Knee Arthroplasty

BACKGROUND

Operative eligibility thresholds based on body mass index (BMI) alone may risk restricting access to improved pain control, function, and quality of life. This study evaluated the use of BMI-cutoffs to offering TKA in avoiding: 1) 90-day readmission, 2) one-year mortality, and 3) failure to achieve clinically important one-year PROMS improvement (MCID).

METHODS

A total of 4126 primary elective unilateral TKA patients from 2015 to 2018 were prospectively collected. For specific BMI(kg/m²) cutoffs: 30, 35, 40, 45, and 50, the positive predictive value (PPV) for 90-day readmission, one-year mortality, and failure to achieve one-year MCID were calculated. The number of patients denied complication-free postoperative courses per averted adverse outcome/failed improvement was estimated.

RESULTS

Rates of 90-day readmission and one-year mortality were similar across BMI categories (P > .05, each). PPVs for preventing 90-day readmission and one-year mortality were low across all models of BMI cutoffs. The highest PPV for 90-day readmission and one-year mortality was detected at cutoffs of 45 (6.4%) and 40 (0.87%), respectively. BMI cutoff of 40 would deny 18 patients 90-day readmission-free, and 194 patients one-year mortality-free postoperative courses for each averted 90-day readmission/one-year mortality. Such cutoff would also deny 11 patients an MCID per avoided failure. Implementing BMI thresholds alone did not influence the rate of improvements in KOOS-PS, KRQOL, or VR-12.

CONCLUSION

Utilizing BMI cutoffs as the sole determinants of TKA ineligibility may deny patients complication-free postoperative courses and clinically important improvements. Shared decision-making supported by predictive tools may aid in balancing the potential benefit TKA offers to obese patients with the potentially increased complication risk and cost of care provision.

The accelerating anuran: evolution of locomotor performance in cane toads (Rhinella marina, Bufonidae) at an invasion front

As is common in biological invasions, the rate at which cane toads (Rhinella marina) have spread across tropical Australia has accelerated through time. Individuals at the invasion front travel further than range-core conspecifics and exhibit distinctive morphologies that may facilitate rapid dispersal. However, the links between these morphological changes and locomotor performance have not been clearly documented. We used raceway trials and high-speed videography to document locomotor traits (e.g. hop distances, heights, velocities, and angles of take-off and landing) of toads from range-core and invasion-front populations. Locomotor performance varied geographically, and this variation in performance was linked to morphological features that have evolved during the toads' Australian invasion. Geographical variation in morphology and locomotor ability was evident not only in wild-caught animals, but also in individuals that had been raised under standardized conditions in captivity. Our data thus support the hypothesis that the cane toad's invasion across Australia has generated rapid evolutionary shifts in dispersal-relevant performance traits, and that these differences in performance are linked to concurrent shifts in morphological traits.

Preoperative cut-off values for body mass index deny patients clinically significant improvements in patient-reported outcomes after total hip arthroplasty

Aims

Thresholds for operative eligibility based on body mass index (BMI) alone may restrict patient access to the benefits of arthroplasty. The purpose of this study was to evaluate the relationship between BMI and improvements in patient-reported outcome measures (PROMs), and to determine how many patients would have been denied improvements in PROMs if BMI cut-offs were to be implemented.

Methods

A prospective cohort of 3,449 primary total hip arthroplasties (THAs) performed between 2015 and 2018 were analyzed. The following one-year PROMs were evaluated: hip injury and osteoarthritis outcome score (HOOS) pain, HOOS Physical Function Shortform (PS), University of California, Los Angeles (UCLA) activity, Veterans Rand-12 Physical Component Score (VR-12 PCS), and VR-12 Mental Component Score (VR-12 MCS). Positive predictive values for failure to improve and the number of patients denied surgery in order to avoid a failed improvement were calculated for each PROM at different BMI cut-offs.

Results

There was a trend to improved outcomes in terms of pain and function improvements with higher BMI. Patients with BMI ≥ 40 kg/m2 had median (Q1, Q3) HOOS pain improvements of 58 points (interquartile range (IQR) 41 to 70) and those with BMI 35 to 40 kg/m2 had median improvements of 55 (IQR 40 to 68). With a BMI cut-off of 30 kg/m2, 21 patients would have been denied a meaningful improvement in HOOS pain score in order to avoid one failed improvement. At a 35 kg/m2 cut-off, 18 patients would be denied improvement, at a 40 kg/m2 cut-off 21 patients would be denied improvement, and at a 45 kg/m2 cut-off 21 patients would be denied improvement. Similar findings were observed for HOOS-PS, UCLA, and VR-12 scores.

Conclusion

Patients with higher BMIs show greater improvements in PROMs. Using BMI alone to determine eligibility criteria did not improve the rate of clinically meaningful improvements. BMI thresholds prevent patients who may benefit the most from surgery from undergoing THA. Surgeons should consider PROMs improvements in determining eligibility for THA while balancing traditional metrics of preoperative risk stratification. Cite this article: Bone Joint J 2020;102-B(6):683–692.

Effects of a Total Knee Arthroplasty Care Pathway on Cost, Quality, and Patient Experience: Toward Measuring the Triple Aim

BACKGROUND

Care pathways are increasingly important as the shift toward value-based care continues; however, there is an inconsistent literature regarding their efficacy. The authors hypothesized that a total knee arthroplasty (TKA) care pathway, at a multihospital health system, would decrease cost, length of stay (LOS), discharges to inpatient facilities, postoperative complications at 90 days, and improve patient experience.

METHODS

A historical control study with multivariable regression was used to determine the association of an evidence-based care pathway with episode of care cost, LOS, discharge disposition, 90-day postoperative complications, and Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) scores.

RESULTS

In total, 6760 primary TKA surgeries were analyzed. Multivariable regression demonstrated that the full protocol period was associated with a decrease in episode of care costs (-8.501%, 95% confidence interval [CI] -9.639 to -7.350), a decrease in LOS (-26.966%, 95% CI -28.516 to -25.382), and an increase in discharges to home (odds ratio [OR] 3.838, 95% CI 3.318-4.446). The full protocol was not associated with a change in 90-day complications (OR 1.067, 95% CI 0.905-1.258) or patient willingness to recommend (OR 1.06, 95% CI 0.72-1.55). Adjusted episode of care cost savings, normalized to average national Medicare reimbursement, were $2360 per patient.

CONCLUSION

TKA care pathways are an effective tool for standardizing care and reducing costs across a large health system. Further investigations are needed to develop interventions to consistently reduce complications. National scale implementation of care pathways in TKA could lead to estimated cost reductions of approximately $1.6 billion annually.

Total Joint Arthroplasty Outcomes in Patients With a Previously Failed Toxicology Screen: A Propensity Score-Matched Analysis

BACKGROUND

The purpose of this study is to review the outcomes of a consecutive series of arthroplasty patients who had previously failed a urine toxicology test. Specifically, we assessed (1) mortality at last follow-up; (2) 90-day readmission and reoperation; (3) rate of complications; and (4) hospital length of stay (LOS) and rates of nonhome discharge.

METHODS

A single-institution, electronic medical record database was queried for primary arthroplasty patients from 2006 to 2017 who had previously failed a day-of-arthroplasty urine toxicology screen. Patients were matched in a 2:1 ratio with toxicology-negative controls.

RESULTS

The mortality rate among toxicology-positive THA patients was 1 of 20 (5%) compared to 0 of 40 among controls (P = .333); the rate of readmission was 3 of 20 (15%) vs 0 of 40 (P = .033); the rate of reoperation was 1 of 20 vs 0 of 40 (P = .333); the rate of surgical complications was 6 of 20 (30%) vs 1 of 40 (2.5%) (P = .004); the rate of medical complication was 4 of 20 (20%) vs 1 of 40 (2.5%) (P = .038); the average LOS was 4 days (range, 1-8 days) vs 2 days (range, 1-10) (P = .002); and the rate of nonhome discharge was 5 of 20 (25%) vs 2 of 40 (5%) patients in the control group (P = .013). The mortality rate among toxicology-positive TKA patients was 1 of 19 (5.3%) compared to 0 of 38 among controls (P = .333); the rate of readmission was 5 of 19 (26.3%) vs 2 of 39 (5.3%) (P = .033); the rate of reoperation was 3 of 19 (15.8%) vs zero (P = .033); the rate of surgical complications was 4 of 21 (21.1%) vs 1 of 38 (2.6%) (P = .038); the rate of medical complications was 5 of 19 (26.3%) vs 2 of 38 (5.3%) (P = .035); the average LOS was 4 days (range, 2-6 days) vs 2 days (range, 1-8 days) (P = .001), the rate of nonhome discharge was 7 of 19 (36.8%) compared to 2 of 38 (5.3%) in the control group (P = .004).

CONCLUSION

These results suggest that toxicology-positive patients require a careful discussion of goals of care before undertaking total hip arthroplasty or total knee arthroplasty.

Same-Day Bilateral Total Knee Arthroplasty Candidacy Criteria Decrease Length of Stay and Facility Discharge

Simultaneous bilateral total knee arthroplasty (SBTKA) may present a higher risk for postoperative complications than unilateral surgery. The authors retrospectively identified 561 patients who underwent SBTKA between 2013 and 2015. The cohort was stratified according to the following appropriateness of care criteria (AOCC): (1) age younger than 70 years; (2) absence of cardiac disease; (3) controlled diabetes; and (4) body mass index less than 30 kg/m². The authors created an AOCC score, with 0 representing the most ideal candidates and 4 representing the least ideal candidates. The cohort included 140 (25%) ideal candidates with a score of 0; the cohort also included 299 (53%) non-ideal candidates with a score of 1, 105 (19%) with a score of 2, 14 (2%) with a score of 3, and 3 (1%) with a score of 4. Ideal candidates had the shortest mean length of stay at 3.6±1.2 days. Length of stay was longer for patients with an AOCC score of greater than 2 compared with those with an AOCC score of 2 or less (5.2±4.3 vs 3.8±1.6 days, P<.001). Ideal candidates were discharged to home more often than other patients (26% vs 13%, P<.001). Although there was no difference in 90-day all-cause complications between ideal and non-ideal candidates (13% vs 16%, P=.400), medical complications trended strongly (6% vs 11%, P=.086). Appropriateness of care criteria for SBTKA patients were associated with shorter length of stay, higher rates of home discharge, and a trend toward lower complication rates. Simultaneous bilateral total knee arthroplasty can offer better outcomes in a subgroup of patients appropriately selected for surgery. Physicians can use these results to counsel their patients about risks and benefits of undergoing SBTKA. [Orthopedics. 2018; 41(5):293-298.].

Quantifying Blood Loss and Transfusion Risk After Primary vs Conversion Total Hip Arthroplasty

BACKGROUND

Primary total hip arthroplasty (THA) and conversion THA may result in substantial blood loss, sometimes necessitating transfusion. Despite the complexities of the latter, both are grouped in the same category for quality assessment and reimbursement. This study's purpose was to compare both blood loss and transfusion risk in primary and conversion THA and identify their associated predictors.

METHODS

A total of 1616 patients who underwent primary and conversion THA at a single hospital from 2009-2013 were reviewed (primary THA = 1575; conversion THA = 41). Demographics, comorbidities, and perioperative data were collected from electronic records. Blood loss was calculated using a validated method. Transfusion triggers were based on standardized criteria. Separate multivariable regression models for blood loss and transfusion were performed.

RESULTS

Conversion THA patients were younger (P = .002), had lower age-adjusted Charlson scores (P = .006), longer surgeries (P < .001), higher blood loss (P < .001), and more transfusions (P < .001). Primary and conversion THA groups were different in terms of surgical approach (P < .001), anesthesia type (P = .002), and venous thromboembolism prophylaxis (P = .01). Compared to primary THA, conversion THA had an average 478.9 mL higher blood loss (P = .003) and increased adjusted odds ratio of 3.2 (P = .019) for transfusion.

CONCLUSION

Conversion THA leads to higher blood loss and transfusion compared with primary THA. These differences were quantified in the present study and showed consistent results between the 2 metrics. The differences between these procedures should be addressed during quality assurance because conversion THA is associated with higher resource utilization, which is important in the allocation of resources and tiered reimbursement strategies.

Rivaroxaban Use for Thrombosis Prophylaxis Is Associated With Early Periprosthetic Joint Infection

BACKGROUND

Periprosthetic joint infection is a disastrous complication after total hip arthroplasty (THA) and total knee arthroplasty (TKA). The use of certain agents to prevent deep vein thrombosis after arthroplasty has been linked to an increased risk of adverse effects including wound drainage and infection. Adverse effects of one alternative, rivaroxaban, was studied in a single community hospital.

METHODS

International Classification of Diseases, Clinical Modification 9 codes were used to identify primary THAs and TKAs in an administrative database at one large-volume community hospital performed in 2012. Patients were divided into 2 groups: the study group received rivaroxaban, whereas the control group received another form of chemical thromboprophylaxis for at least 2 weeks postoperative. Demographics, risk factors, and illness severity scores were collected for each group. The primary measured outcome was the incidence of deep surgical site infection (SSI) within 30 days postoperative.

RESULTS

A total of 639 TKA or THA patients were included, with 159 patients who received rivaroxaban and 480 who received another form of chemical thromboprophylaxis. There were no significant differences between groups regarding demographics, risk factors, or illness severity scores. Incidence of early deep SSI in the rivaroxaban group was higher than in the control group (2.5% vs 0.2%; P < .015).

CONCLUSION

The use of rivaroxaban for thromboprophylaxis led to a significantly increased incidence of deep SSI in a continuous series of patients undergoing primary THA and TKA in a single institution.

Risk factors for dislocation after revision total hip arthroplasty

BACKGROUND

Despite dislocation being the most frequent complication after revision THA, risk factors for its occurrence are not completely understood.

QUESTIONS/PURPOSES

We therefore (1) determined the overall risk of dislocation after revision THA in a large series of revision THAs using contemporary revision techniques, (2) identified patient-related risk factors predicting dislocation, and (3) identified surgical variables predicting dislocation.

METHODS

We performed 1211 revision THAs between June 2004 and October 2010 in 576 women and 415 men who had a mean age of 64.7 years (range, 25-95 years) at time of surgery. Forty-six (4%) were lost to followup and 13 died (1%), leaving 1152 hips followed for a minimum of 90 days (mean, 2 years; range, 90 days to 7.1 years). Multivariate logistic regression was performed to identify risk factors for dislocation. The model was also tested on patients followed for a minimum 1 year to assess any difference in longer followup.

RESULTS

One hundred thirteen patients dislocated over the followup period (9.8%). Factors that were different between patients who dislocated and those who remained stable included a history of at least one previous dislocation (odds ratio [OR] = 2.673), abductor deficiency (OR = 2.672), and Paprosky acetabulum class (OR = 1.522). Use of a constrained liner (OR = 0.503) and increased femoral head size (OR = 0.942) were protective against dislocation, while with longer followup a constrained liner was no longer significant.

CONCLUSIONS

Dislocation remains a common problem after revision THA. Identifying these risk factors can assist in patient education and surgical planning. Recognition of these risk factors in both patient type and surgical strategy is important for the surgeon performing revision THA and for minimizing these risks.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

The use of abduction bracing for the prevention of early postoperative dislocation after revision total hip arthroplasty

One potential strategy to decrease the risk of dislocation after revision total hip arthroplasty (THA) is the use of an abduction brace to limit flexion and adduction. The purpose of this study was to compare the dislocation rate after revision THA between patients treated with or without an abduction brace. Data were obtained from 1211 revision THAs performed in 610 women and 518 men who had a mean age of 64.7 years (range, 22-95 years) and were followed up for a minimum of 90 days. Five hundred two patients were braced, whereas 650 were not. The 90-day dislocation rate among patients who wore a brace was 5.2% compared with 5.7% in the nonbrace group (P = .70). Multivariate regression found no benefit to bracing (P = .37), while controlling for factors found to significantly affect dislocation rate in this population. Our data do not support the routine use of an abduction brace to aid in the prevention of dislocation.

Prospective randomized evaluation of the need for blood transfusion during primary total hip arthroplasty with use of a bipolar sealer

BACKGROUND

Blood loss during total hip arthroplasty can be substantial and may lead to adverse patient outcomes and increased health-care costs. Many blood-management options are available for these procedures. The purpose of the present study was to test the hemostatic efficacy of a bipolar sealer used during total hip arthroplasty in order to determine whether its use results in significantly lower transfusion requirements and/or improved clinical, functional, and health-related quality-of-life outcomes in healthy patients.

METHODS

This prospective, single-center, randomized, double-blinded study was designed to enroll a total of 140 patients. Patients with a low preoperative hemoglobin level or a history of bleeding abnormalities and other medical conditions were excluded. Patients were randomized to either the treatment arm (radiofrequency energy with use of the Aquamantys 6.0 bipolar sealer) or control arm (standard Bovie electrocautery). The primary outcome measure was the transfusion requirement, and the secondary outcome measures were intraoperative estimated blood loss, postoperative hemoglobin levels, perioperative narcotic usage, length of hospital stay, postoperative pain scores, and postoperative function as measured with the Harris hip score and the Short Form-12 quality-of-life score.

RESULTS

Seventy-one patients were assigned to the treatment arm, and sixty-nine were assigned to the control arm. The mean number of units of blood transfused for all patients in the study and control arms were 0.38 and 0.44, respectively (p = 0.72). The transfusion requirements were similar in the two groups, with fifteen of seventy-one patients in the treatment arm and fourteen of sixty-nine patients in the control arm requiring a transfusion (p = 0.9). No significant differences were detected between the groups in terms of estimated blood loss, postoperative hemoglobin levels, perioperative narcotic usage, length of hospital stay, postoperative pain scores, Harris hip scores, or Short Form-12 scores.

CONCLUSIONS

In this patient population, there were no significant differences between the treatment and control groups in terms of the need for blood transfusions or overall blood loss. Given these findings, we have discontinued the use of this bipolar sealing device in uncomplicated primary total hip arthroplasty patients at our institution.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions to Authors for a complete description of levels of evidence.

Robotic testing of proximal tibio-fibular joint kinematics for measuring instability following total knee arthroplasty

Pain secondary to instability in total knee arthroplasty (TKA) has been shown to be major cause of early failure. In this study, we focused on the effect of instability in TKA on the proximal tibio-fibular joint (PTFJ). We used a robotics model to compare the biomechanics of the PTFJ in the native knee, an appropriately balanced TKA, and an unbalanced TKA. The tibia (n = 5) was mounted to a six-degree-of-freedom force/torque sensor and the femur was moved by a robotic manipulator. Motion at the PTFJ was recorded with a high-resolution digital camera system. After establishing a neutral position, loading conditions were applied at varying flexion angles (0°, 30°, and 60°). These included: internal/external rotation (0 Nm, ±5 Nm), varus/valgus (0 Nm, ±10 Nm), compression (100 N, 700 N), and posterior drawer (0 N, 100 N). With respect to anterior displacement, external rotation had the largest effect (coefficient = 0.650; p < 0.0001). Polyethylene size as well as the interaction between polyethylene size and flexion consistently showed substantial anterior motion. Flexion and mid-flexion instability in TKA have been difficult to quantify. While tibio-femoral kinematics is the main aspect of TKA performance, the effects on adjacent tissues should not be overlooked. Our data show that PTFJ kinematics are affected by the balancing of the TKA.

Influence of technique with distally fixed modular stems in revision total hip arthroplasty

Distally fixed modular implants have seen a recent increase in use, to manage proximal femoral bone loss often encountered during revision total hip arthroplasty (THA). Forty-three distally fixed modular stems implanted at our institution between 1999 and 2006 were clinically and radiographically reviewed. These patients had either a minimum 2-year follow-up (average, 2.4 years; range, 2-5.6 years) or failure (ie, explant or rerevision required). Eleven stems subsided, and 4 were rerevised (n = 4), for a rate of 9.3%. All revised stems were radiographically undersized, emphasizing the importance of the technique. Although being a valuable option in revision THA, these stems are not free of complications. The high rate of subsidence encountered in our early experience shows that there is a learning curve. This complication is preventable by avoiding undersizing.

Predicting patient discharge disposition after total joint arthroplasty in the United States

The purpose of this study was to develop an easily administered tool to preoperatively predict patient discharge disposition after total joint arthroplasty in the United States. Data were collected in a retrospective review of 517 medical charts and analyzed using logistic regression to develop a model for predicting the likelihood that a patient will not be discharged directly home. The resulting regression model was the basis for the nomogram, named the Predicting Location after Arthroplasty Nomogram. This model demonstrated a bootstrap-corrected concordance index of 0.867, excellent calibration, and external validation as demonstrated by a concordance index of 0.861. Preoperative knowledge that a patient is likely to require an extended care facility allows the clinical care team to make appropriate arrangements and avoid potential delays in patient discharge.

Venous thromboembolic disease reduction with a portable pneumatic compression device

This study compares a miniaturized, portable, sequential, pneumatic compression device (ActiveCare continuous enhanced circulation therapy [CECT] system) (Medical Compression Systems Ltd, Or Aqiva, Israel), with a nonmobile, nonsequential device on the ability to prevent postoperative deep venous thrombosis (DVT) after joint arthroplasty. All patients were treated with low-molecular-weight heparin, application of 1 of the 2 devices perioperatively, and routine duplex screening. The CECT system had better compliance (83% of the time vs 49%), lower rates of DVT (1.3% compared with 3.6%), reduction in clinically important pulmonary embolism (0 compared to 0.66%), and shorter length of hospital stay (4.2 vs. 5.0 days). The portable CECT system proved significantly more effective than the standard intermittent pneumatic compression when used in conjunction with low-molecular-weight heparin for DVT prevention in high-risk orthopedic patients.

Macular spectral-domain optical coherence tomography in patients with X linked retinoschisis

AIM

To evaluate macular anatomy in patients with X linked retinoschisis (XLRS) using spectral-domain optical coherence tomography (SD-OCT).

METHODS

Consecutive observational case series. Clinical features were obtained through retrospective chart review. Only eyes without prior surgical interventions and those scanned with SD-OCT were included. The OCT images were analysed.

RESULTS

Fourteen eyes of seven males with XLRS scanned with SD-OCT, age 5 to 45 years, were identified. On clinical examination, stellate spoke-like cystic maculopathy was present in nine eyes, and an atrophic foveal lesion in five eyes. SD-OCT revealed cystoid spaces accounting for retinal splitting in the inner nuclear layer in 12 eyes, and outer plexiform layer in two eyes of one patient. A few small cysts, not accounting for the foveal splitting, were seen in the outer nuclear layer in four eyes and in the ganglion cell layer and/or nerve fibre layer in six eyes.

CONCLUSIONS

SD-OCT localised the foveomacular retinoschisis in XLRS to the retinal layers deeper than the nerve fibre layer. In the present study, the foveomacular schisis was seen most frequently in the inner nuclear layer.

Lack of effect of SU1498, an inhibitor of vascular endothelial growth factor receptor-2, in a transgenic murine model of retinoblastoma

SU1498, a tyrosine kinase inhibitor of vascular endothelial growth factor receptor 2 (VEGFR-2), has activity against retinal neovascular diseases. To determine if this drug might have clinical utility against retinoblastoma, we evaluated the effects of SU1498, as well as the expression of VEGFR-2, in a transgenic animal model of retinoblastoma. Optical coherence tomography (OCT) was evaluated as a technology to measure retinal tumors in vivo, in response to treatment. Immunofluorescence analysis was performed to evaluate the distribution and expression of VEGFR-2 in enucleated eyes from LHβTag transgenic mice and controls at 4, 8, 12, and 16 weeks of age. VEGFR-2 and phosphorylated (p)VEGFR-2 levels were quantitated by Western blot. OCT was used to pair 10-week-old animals based on tumor volume (n=10), and these animals were treated with 6 periocular injections of SU1498 (50mg/kg, given twice weekly) or vehicle for 3 weeks. Tumor burden was determined by histology and in vivo imaging by OCT. VEGFR-2 and pVEGFR-2 expression levels were upregulated during tumorigenesis. However, SU1498 did not significantly reduce tumor burden compared to vehicle (p=0.29). OCT imaging of one matched pair demonstrated equivalent, linear tumor growth despite treatment with SU1498. Retinal tumors can be followed non-invasively and quantitatively measured with OCT. VEGFR-2 is strongly upregulated during tumorigenesis in transgenic retinoblastoma; however, SU1498 does not decrease tumor volume in transgenic murine RB at the studied dose and route of administration.

Corneal graft survival and intraocular pressure control after penetrating keratoplasty and glaucoma drainage device implantation

OBJECTIVE

To investigate corneal graft survival rates and intraocular pressure (IOP) control in eyes after penetrating keratoplasty (PK) and glaucoma drainage device (GDD) implantation.

DESIGN

Retrospective, comparative, consecutive case series.

PARTICIPANTS

All patients who underwent PK and GDD implantation at the Bascom Palmer Eye Institute between January 1, 1993 and October 31, 1998.

MAIN OUTCOME MEASURES

Graft clarity and IOP control.

RESULTS

Of the 72 eyes in 72 patients identified, 47 (65%) underwent combined PK and GDD implantation, and 25 (35%) underwent GDD placement after PK (2-30 months after PK; median, 13 months). The GDD type was Baerveldt 350 mm(2) in 57 eyes, Ahmed in 9, Krupin in 2, and other in 4 eyes. The GDD was placed in the anterior chamber in 54 eyes (75%) and in the vitreous cavity in 18 eyes (25%). Preoperative IOP was 11 to 53 mmHg with or without antiglaucoma medications in 16 eyes (30%) with the GDD implanted in the anterior chamber and in 4 eyes (22%) with the GDD placed in the vitreous cavity (P = 0.76). At 1 year after GDD implantation, the graft was clear in 26 eyes (48%) with the GDD in the anterior chamber compared with 15 eyes (83%) with the GDD in the vitreous cavity (P = 0.013). Forty-eight eyes (89%) with the GDD in the anterior chamber and 18 eyes (100%) with the GDD in the vitreous cavity had IOP between 5 and 21 mmHg with or without antiglaucoma medications (P = 0.33). The mean reduction in IOP, 1 year after surgery, was 12 mmHg among eyes with the GDD in the anterior chamber, compared with 17 mmHg among eyes with the GDD in the vitreous cavity (P = 0.13)

CONCLUSIONS

Corneal graft survival at 1 year is significantly higher among eyes with the GDD implanted in the vitreous cavity compared with those in which the GDD is implanted in the anterior chamber. The IOP was significantly lower at 1 year after surgery compared with before surgery in both groups, and there was no significant difference between the groups in IOP control and amount of IOP reduction. There was no significant difference in corneal graft survival or IOP control between eyes with the GDD implanted concurrently with the PK versus after the PK.

Surgical removal of submacular choroidal neovascularization: a clinicopathologic study and factors influencing visual outcomes

BACKGROUND AND OBJECTIVE

Clinical and histopathologic characteristics of submacular choroidal neovascular membranes (CNV) are investigated and features predictive of postoperative complications or poorer visual outcome following CNV removal are identified.

MATERIALS AND METHODS

Records of patients who underwent submacular CNV removal at Bascom Palmer Eye Institute between 1991 and 1998 are reviewed.

RESULTS

At 6 months postoperatively, vision was stable or improved in 19/26 (73%) eyes, with 15/26 (58%) having 20/200 to 20/400 vision. Postoperative retinal detachment occurred more commonly in age-related macular degeneration eyes (AMD) (P <0.05), and CNV recurrence occurred most frequently in presumed ocular histoplasmosis (POHS) eyes (P <0.05). The one eye with an extrafoveal CNV in-growth site had the largest improvement in vision postoperatively. Choroid in the specimen was associated with worse postoperative vision (P = 0.05).

CONCLUSION

Submacular CNV removal achieves visual stabilization at the 20/200 to 20/400 level in most eyes. Potential risk factors for postoperative complications or poorer visual outcome include the underlying disease process, subfoveal in-growth site of CNV, and presence of choroid in the specimen.

Echography of retinoblastoma: histopathologic correlation and serial evaluation after globe-conserving radiotherapy or chemotherapy

PURPOSE

To assess the sensitivity of echography in detecting retinoblastoma, compare tumor features observed by echography with histopathology data, and assess the usefulness of echography in serially following retinoblastoma tumors after globe-conserving treatments.

METHODS

The medical and echography records of all patients treated for retinoblastoma at the Bascom Palmer Eye Institute between 1991 and 1997 were reviewed. All eyes underwent pretreatment echographic evaluation, and eyes treated with external beam radiotherapy, brachytherapy, or chemotherapy underwent serial follow-up echography.

RESULTS

Sixty-nine eyes of 48 patients were identified. Echography demonstrated evidence of retinoblastoma in 69 of 69 (100%) eyes and calcification in 63 (91.3%) eyes. Histopathology was superior to echography in detecting optic nerve invasion, extraocular extension, and presence of calcification.

CONCLUSION

Echography is a useful adjunct to indirect ophthalmoscopy in establishing the diagnosis of retinoblastoma. While not as specific as histopathology, echographic evaluation before and after treatment of retinoblastoma permits monitoring of treatment response and may aid in detecting recurrent tumor growth or failure to respond to treatment.

Traumatic macular hole: observations, pathogenesis, and results of vitrectomy surgery

PURPOSE

To review our experience with vitrectomy surgery techniques for the treatment of traumatic macular holes and the biomicroscopic and surgical findings.

DESIGN

Retrospective noncomparative, multicenter, case series.

PARTICIPANTS AND INTERVENTION

Twenty-five patients with traumatic macular hole underwent surgical repair.

INTERVENTION

Vitrectomy with membrane peeling and gas injection followed by prone positioning for 7 to 14 days.

MAIN OUTCOME MEASURES

Postoperative evaluation included visual acuity testing, closure of the macular hole, and ocular complications.

RESULTS

The macular hole was successfully closed in 24 of 25 cases (96%). The visual acuity improved two or more lines in 21 (84%) cases, and 16 (64%) achieved 20/50 or better vision.

CONCLUSIONS

Vitrectomy surgery can successfully close macular holes associated with trauma and improve vision.

Outcomes of vitreoretinal surgery for complications of branch retinal vein occlusion

OBJECTIVE

To investigate outcomes of vitreoretinal surgery for complications of branch retinal vein occlusion (BRVO).

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

The medical records of all patients who underwent vitreoretinal surgery for complications of BRVO at Bascom Palmer Eye Institute between January 1, 1991 and December 31, 1998 were reviewed. Thirty-six eyes from 36 consecutive patients were identified.

MAIN OUTCOME MEASURES

Visual acuity outcomes include preservation of preoperative visual acuity and visual acuity greater than or equal to 20/40, 20/200 and 5/200. When preoperative retinal detachment was present, the anatomic outcome assessed was complete retinal attachment. Postoperative event rates of retinal detachment, vitreous hemorrhage, epiretinal membrane (ERM), and cataract were tabulated. All outcomes were assessed at 6 months.

RESULTS

Surgical indications included nonclearing vitreous hemorrhage (17 patients), traction retinal detachment involving the macula (15), and ERM (4). Mean follow-up was 19 months. Preoperatively, best-corrected vision was greater than or equal to 20/200 in 19/36 (53%) eyes. Six months postoperatively, best-corrected vision was greater than or equal to 20/40 in 12/36 (33%) eyes, greater than or equal to 20/200 in 27/36 (75%) eyes, and greater than or equal to 5/200 in 31/36 (86%) eyes. Postoperative complications included retinal detachment (2/36; 6% eyes), ERM (3; 8%), vitreous hemorrhage (2; 6%), suprachoroidal hemorrhage (1; 3%), central retinal vein occlusion (1; 3%), and central retinal artery occlusion (1; 3%). Clinical features associated with better visual outcome include better preoperative visual acuity (P: = 0.05), absence of preoperative afferent pupillary defect (P: = 0.01), and absence of preoperative macular edema (P: = 0.08).

CONCLUSIONS

Following surgery, retinal attachment and improved visual acuity were achieved in the majority of patients. Pre-existing pathology and postoperative complications may limit final vision in eyes with BRVO.

Evaluation of chemoprophylaxis in patients with unilateral retinoblastoma with high-risk features on histopathologic examination

OBJECTIVES

To identify risk factors for metastatic disease on histopathologic specimens of enucleated eyes from patients with unilateral retinoblastoma, and to evaluate the value of chemoprophylaxis in preventing disease dissemination.

METHODS

Medical records from patients with unilateral retinoblastoma who underwent primary enucleation were reviewed at the University of California, San Francisco (1977-1998) and Bascom Palmer Eye Institute, University of Miami, Miami, Fla (1991-1998). All routine histopathologic specimens were reexamined. The extent of tumor invasion into the optic nerve or ocular coats and the prescribed chemoprophylactic regimen were recorded.

RESULTS

This retrospective study included 129 patients followed for a median of 54 months. Three patients had tumor invading the sclera. The optic nerve was involved to some extent in 82 patients, 11 of whom had tumor extension beyond the lamina cribrosa. The surgical margin of the optic nerve was involved in an additional 4 patients. The choroid was involved in 43 patients, and was considered massively affected in 12 patients. Anterior segment involvement was observed in 10 patients. Postenucleation chemoprophylaxis was administered to 4 of 4 patients who had tumor cells at the surgical margin of the optic nerve and to 7 of 11 patients with postlaminar disease, all of whom had at least 1 mm of postlaminar tumor extension. External beam radiotherapy was administered to 3/4 and 1/11 of these patients, respectively. Chemoprophylaxis was not administered to patients with choroidal or anterior chamber involvement unless the optic nerve was also involved beyond the lamina cribrosa. One patient with tumor extending to the surgical margin of the optic nerve died of metastatic disease.

CONCLUSIONS

Chemoprophylaxis is necessary for patients with tumor extending to the surgical margin of the optic nerve and is likely to be beneficial in preventing metastases in patients with tumor extending beyond the lamina cribrosa. We did not offer chemoprophylaxis to patients with prelaminar optic nerve disease or isolated choroidal involvement, and these patients remained free of disseminated disease.