Higher body mass index leads to longer operative time in total knee arthroplasty

Factors Affecting Operating Room Scheduling Accuracy for Primary and Revision Total Knee Arthroplasty: A Retrospective Study

BACKGROUND

Optimizing operating room (OR) scheduling accuracy is important for improving OR efficiency and maximizing value of total knee arthroplasty (TKA). However, data on factors that may impact TKA OR scheduling accuracy are limited.

MATERIALS AND METHODS

A retrospective review of 7655 knee arthroplasties (6999 primary TKAs and 656 revision TKAs) performed between January 2020 and May 2023 was conducted. Patient baseline characteristics, surgeon experience (years in practice), as well as actual vs scheduled OR times were collected. Actual OR times that were at least 15% shorter or longer than scheduled OR times were considered to be clinically important. Logistic regression analyses were employed to assess the influence of specific patient and surgeon factors on OR scheduling inaccuracies.

RESULTS

Using adjusted odds ratio, patients with primary TKA who had a lower body mass index (P<.001) were independently associated with overestimation of scheduled surgical time. Conversely, younger age (P<.001), afternoon procedure start time (P<.001), surgeons with less than 10 years of experience (P=.037), and higher patient body mass index (P<.001) were associated with underestimation of scheduled surgical time. For revision TKA, female sex (P=.021) and morning procedure start time (P=.038) were associated with overestimation of scheduled surgical time, while surgeons with less than 10 years of experience (P=.014) and patients who underwent spinal/epidural/block anesthesia (P=.038) were associated with underestimation of scheduled surgical time.

CONCLUSION

This study highlights patient, surgeon, and intraoperative variables that impact the accuracy of scheduling for TKA procedures. Health systems should take these variables into consideration when creating OR schedules to fully optimize resources and available space. [Orthopedics. 2024;47(5):313-319.].

Acute Surgical Site Complications in Direct Anterior Total Hip Arthroplasty: Impact of Local Subcutaneous Tissue Depth and Body Mass Index

Background

Body mass index (BMI) is an imperfect measure of patients' adiposity and operative risk. Radiographic and direct subcutaneous measurements have been utilized in attempts to more accurately characterize the risk of postoperative complications, including surgical site infection. This study aims to evaluate whether direct tissue depth measurement is a more accurate predictor of skin complication following direct anterior total hip arthroplasty (THA).

Methods

A retrospective chart review of patients who underwent elective THA between April 30, 2020, and January 31, 2023, was performed. Baseline demographics, antibiotics, anticoagulation, and intraoperatively measured tissue depths at proximal, middle, and distal portions of the incision were recorded. Patient follow-up was reviewed to assess the development of skin complication in the acute postoperative period.

Results

Data were collected from 280 patients who underwent THA via direct anterior approach by a single surgeon. The mean age was 66.0 years, and 52.1% were female. A total of 18/280 (6.4%) patients developed an abrasion (5/18) or superficial surgical site infection (13/18) within the first 60 days postoperatively. Patients who developed skin complications had a significantly higher BMI (33.7 kg/m2 vs 29.9 kg/m2; P = .0021). Patients with a BMI >30 kg/m2 had more than 5 times increased odds of developing a superficial skin complication in the acute 60-day postoperative period compared to those with a BMI <30 kg/m2 (Odds ratio = 5.318, P = .0059). None of the measured tissue depths, nor their average together, were shown to be significant predictors of skin complications.

Conclusions

This study showed that BMI is a significant predictor of acute skin complications in direct anterior THA patients. No other significant predictors were found to be associated with increased risk, including proximal, middle, and distal tissue depths.

Quantifying the effect of shoulder size on operation duration: an analysis of stapes surgery outcomes

OBJECTIVE

To investigate the effect of body mass index on hearing outcomes, operative time and complication rates following stapes surgery.

METHOD

This is a five-year retrospective review of 402 charts from a single tertiary otology referral centre from 2015 to 2020.

RESULTS

When the patient's shoulder was adjacent to the surgeon's dominant hand, the average operative time of 40 minutes increased to 70 minutes because of a significant positive association between higher body mass index and longer operative times (normal body mass index group (<25 kg/m2) r = 0.273, p = 0.032; overweight body mass index group (25-30 kg/m2) r = 0.265, p = 0.019). Operative times were not significantly longer upon comparison of low and high body mass index groups without stratification by laterality (54.9 ± 19.6 minutes vs 57.8 ± 19.2 minutes, p = 0.127).

CONCLUSION

There is a clinically significant relationship between body mass index and operating times. This may be due to access limitations imposed by shoulder size.

Impact of obesity on outcomes after surgical stabilization of multiple rib fractures: Evidence from the US nationwide inpatient sample

BACKGROUND

Obesity is a global health issue with increasing prevalence. Surgical procedures, such as surgical stabilization of rib fractures (SSRF), may be affected by obesity-related complications. The objective of the study is to investigate the effects of obesity on SSRF outcomes in multiple rib fractures.

METHODS

This retrospective study analyzed data from adults aged ≥ 20 years in the Nationwide Inpatient Sample (NIS) database diagnosed with multiple rib fractures who underwent SSRF between 2005 and 2018. It investigated the relationship between obesity and in-patient outcomes, such as discharge status, length of stay (LOS), in-hospital mortality, hospital costs, and adverse events using logistic and linear regression analyses.

RESULTS

Analysis of data from 1,754 patients (morbidly obese: 87; obese: 106; normal weight: 1,561) revealed that morbid obesity was associated with longer LOS (aBeta = 0.07, 95% CI: 0.06, 0.07), higher hospital costs (aBeta = 47.35, 95% CI: 38.55, 56.14), increased risks of adverse events (aOR = 1.63, 95% CI: 1.02, 2.61), hemorrhage/need for transfusion (aOR = 1.77, 95% CI: 1.12, 2.79) and mechanical ventilation ≥ 96 hours (aOR = 2.14, 95% CI: 1.28, 3.58) compared to normal weight patients. Among patients with flail chest, morbid obesity was significantly associated with tracheostomy (aOR = 2.13, 95% CI: 1.05, 4.32), ARDS/respiratory failure (aOR = 2.01, 95% CI: 1.09, 3.70), and mechanical ventilation ≥ 96 hours (aOR = 2.80, 95% CI: 1.47, 5.32). In contrast, morbid obesity had no significant associations with these adverse respiratory outcomes among patients without a flail chest (p > 0.05).

CONCLUSIONS

Morbid obesity is associated with adverse outcomes following SSRF for multiple rib fractures, especially for flail chest patients.

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).

Moving beyond frailty: Obesity paradox persists in lung resection

BACKGROUND

The apparent protective effect of high body mass index on postoperative outcomes, termed the "obesity paradox," has been postulated to reflect the relative frailty of patients without obesity. We wanted to examine the independent association between body mass index and outcomes after anatomic lung resection.

METHODS

All adults undergoing elective lung resection for cancer were identified in the 2012-2020 National Surgical Quality Improvement Program. The modified Frailty Index quantified degree of patient frailty. Malnutrition was defined as a preoperative serum albumin <3.5g/dL. Multivariable regressions were used to examine the independent association of body mass index and major adverse events, analyzed as a composite of 30-day mortality, postoperative complications, and unplanned reoperation.

RESULTS

Of an estimated 20,099 patients meeting study criteria, 6,424 (32.0%) had obesity. Relative to others, patients with obesity were significantly younger (49.3 vs 50.3 years), more commonly White (78.1 vs 74.9%), and more frequently frail (modified Frailty Index >1: 35.7 vs 22.5%, all P < .001). There was no significant difference in malnutrition rates (7.6 vs 8.4%, P = .05) or extent of resection between groups. After adjustment, obesity was associated with decreased odds of major adverse events (adjusted odds ratio 0.86, 95% confidence interval 0.78-0.94).

CONCLUSION

The present findings uphold the canonical obesity paradox in anatomic lung resection, despite adjustment for frailty and malnutrition. Further studies are warranted to characterize the nature of this association; however, our results may inform efforts to optimize risk stratification and patient selection for surgical intervention.

Fat tissue is a poor predictor of 1 year outcomes after total knee arthroplasty: A secondary analysis of a randomized clinical trial

BACKGROUND AND OBJECTIVE

Obesity may increase the risk of adverse events after total knee arthroplasty (TKA). Although body mass index (BMI) is commonly used in categorizing obesity, its accuracy is limited. Body fat percentage (BFP) might indicate adiposity status and predict arthroplasty-related outcomes better than BMI. We investigated whether BFP is predictive of TKA-related outcomes.

METHODS

In this secondary analysis, BFP was measured preoperatively from 294 participants of a randomized trial that investigated the effects of tourniquet and anesthesia methods on TKA. Data concerning in-hospital assessments and events were collected. Knee range of motion (ROM) was measured, the Brief Pain Inventory-short form and Oxford Knee Score questionnaires were used to collect data on patient-reported pain and function, and the 15-dimensional health-related questionnaire was used to assess quality of life preoperatively and 3 and 12 months postoperatively. The patients reported satisfaction to TKA 3 and 12 months postoperatively. Data concerning infectious and thromboembolic events within 90 postoperative days and revision surgery, manipulation under anesthesia, and mortality within 1 year were collected. A separate post hoc analysis was performed for 399 participants to assess the effects of BMI on the respective outcomes.

RESULTS

A 1-unit increase in BFP affected the ROM by -0.37° (95% confidence interval (CI) = -0.60 to -0.13) 12 months after surgery. BFP was not significantly associated with the operation time or adverse events. However, the number of most adverse events remained too low for adjusted analysis. A 1-unit increase in BMI increased the operation time by 0.57 min (95% CI = 0.10 to 1.04) and affected the ROM by -0.47° (95% CI = -0.74 to -0.20) 12 months postoperatively. Neither BFP nor BMI was significantly associated with acute pain, pain management, length of stay, or with pain, function, quality of life, or satisfaction to TKA at 12 months after surgery.

CONCLUSIONS

BFP seems to be a poor predictor of in-hospital results and of patient-reported outcomes 1 year after TKA.

TWITTER HANDLE

In this secondary analysis of a randomized trial, body fat percentage was poorly predictive of clinical outcomes during hospital stay and of patient-reported outcomes 1 year after TKA.

Patients of Obese Representation Require Longer Operative Times: An Evaluation of Acetabular and Pelvic Ring Operative Duration

Recent literature has determined that operative times for the obese population are greater for both elective and nonelective orthopedic procedures. If time allotted for a given surgical procedure is used as a measure of procedural difficulty, then consideration can be given for using an additional coding modifier (i.e., Modifier 22) for the increased skill and effort associated with longer procedures. A retrospective chart review was conducted on all patients who underwent surgical treatment for an acute fracture about the pelvis at an urban level-1 trauma center from October 1, 2010 through October 31, 2018. After allowing for both inclusion and exclusion criteria, 102 patients with acetabular fractures and 55 patients with pelvic ring injuries were included in this investigation. The obese population within the acetabular fracture cohort demonstrated significantly longer mean times for the duration of surgery, total time in spent in the operating room, and duration under anesthesia (P values of 0.038, 0.05 and 0.035, respectively). Similar results were observed with the pelvic ring injury cohort, with significantly longer procedural times (P = 0.019), total time in the operating room (P = 0.034), and total duration under anesthesia (P = 0.0395). A trend towards a greater risk of infection was found in obese patients (7%) when compared with nonobese patients (1.6%) within the acetabular fracture subset (P = 0.093). Operative duration for acetabular fractures and pelvic ring injuries is significantly longer in the obese population. Furthermore, this indicates that a Modifier 22 may be justified for the surgical treatment of these injuries in the obese and morbidly obese patient populations.

Single Surgeon versus Co-Surgeons in Primary Total Joint Arthroplasty: Does "Two Is Better than One" Apply to Surgeons?

BACKGROUND

As the demand for total joint arthroplasties (TJA) increases steadily, so does the pressure to train future surgeons and, at the same time, achieve optimal outcomes. We aimed to identify differences in operative times and short-term surgical outcomes of TJAs performed by co-surgeons versus a single attending surgeon.

METHODS

A retrospective analysis of 597 TJAs, including 239 total hip arthroplasties (THAs) and 358 total knee arthroplasties (TKAs) was conducted. All operations were performed by one of four fellowship-trained attending surgeons as the primary surgeon. The assisting surgeons were either attendings or residents.

RESULTS

In 51% of THA and in 38% of TKA, two attending surgeons were scrubbed in. An additional scrubbed-in attending was not found to be beneficial in terms of surgical time reduction or need for revision surgeries within the postoperative year. This was also true for THAs and for TKAs separately. An attending co-surgeon was associated with a longer hospital stay (p = 0.028). Surgeries performed by fewer surgeons were associated with a shorter surgical time (p = 0.036) and an increased need for blood transfusion (p = 0.033). Neither the rate of intraoperative complications nor revisions differed between groups, regardless of the number of attending surgeons scrubbed in or the total number of surgeons.

CONCLUSION

A surgical team comprised of more than a single attending surgeon in TJAs was not found to reduce surgical time, while the participation of residents was not related with worse patient outcomes.

Effect of body mass index on duration of total knee replacement surgery: A prospective cross sectional study

Introduction

Obesity and increased BMI has raised concerns throughout the globe. As obesity is often associated with many serious medical conditions. Obesity, older age and gender are major contributing factors for knee replacement surgeries. We aimed to compare the mean duration of surgery in obese and non-obese patients undergoing total knee replacement.

Methods

A Cross-sectional study is conducted at the orthopedic department at Shifa international hospital, Islamabad during June 2021–Dec 2021. Study is conducted to assess the effect of BMI on duration of total knee arthroplasty. Sample size was calculated to be 105 with 95% confidence limit. Data will be analyzed using SPSS version 22. Quantitative variables like age, BMI and duration of surgery were presented as mean and standard deviation. Qualitative variables like gender, laterality (unilateral/bilateral), and ASA were presented as frequency and percentage.

Results

There were more females undergoing the procedure than males. The predominant age group was found to be 56–65 years. On BMI classification scale, a far greater number of individuals were found to be obese constituting more than ⅗ of the study population and almost ⅕ of the patients were overweight. The Association of BMI Classification & Duration of Surgery has a significant p value of 0.00.

Conclusion

A linear and direct relation was observed between body mass index and duration of surgery. There may be other contributing factors and will need more data and research.

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The body mass index (BMI) is widely recognized as a prognostic factor in multiple operations.

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High body mass index (BMI) is associated with increased rates of complications after total knee arthroplasty.

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Our study finds a strong association of Age, Gender & ASA Grade with BMI.

Predicting surgical operative time in primary total knee arthroplasty utilizing machine learning models

BACKGROUND

Prolonged surgical operative time is associated with postoperative adverse outcomes following total knee arthroplasty (TKA). Increasing operating room efficiency necessitates the accurate prediction of surgical operative time for each patient. One potential way to increase the accuracy of predictions is to use advanced predictive analytics, such as machine learning. The aim of this study is to use machine learning to develop an accurate predictive model for surgical operative time for patients undergoing primary total knee arthroplasty.

METHODS

A retrospective chart review of electronic medical records was conducted to identify patients who underwent primary total knee arthroplasty at a tertiary referral center. Three machine learning algorithms were developed to predict surgical operative time and were assessed by discrimination, calibration and decision curve analysis. Specifically, we used: (1) Artificial Neural Networks (ANNs), (2) Random Forest (RF), and (3) K-Nearest Neighbor (KNN).

RESULTS

We analyzed the surgical operative time for 10,021 consecutive patients who underwent primary total knee arthroplasty. The neural network model achieved the best performance across discrimination (AUC = 0.82), calibration and decision curve analysis for predicting surgical operative time. Based on this algorithm, younger age (< 45 years), tranexamic acid non-usage, and a high BMI (> 40 kg/m²) were the strongest predictors associated with surgical operative time.

CONCLUSIONS

This study shows excellent performance of machine learning models for predicting surgical operative time in primary total knee arthroplasty. The accurate estimation of surgical duration is important in enhancing OR efficiency and identifying patients at risk for prolonged surgical operative time.

LEVEL OF EVIDENCE

Level III, case control retrospective analysis.

Comparison of Operative Times in Primary Bilateral Total Knee Arthroplasty Performed by a Single Surgeon

Purpose: Prolonged operative time (OT) is associated with adverse complications after total knee arthroplasty (TKA). The purpose of this study was to determine whether preoperative factors, such as sex, age, body mass index, body weight (BW), body height, American Society of Anesthesiologists grade, tibiofemoral angle, hospital for special surgery scores, surgical side, surgical order, and calendar year of surgery, affect OT. Methods: One hundred and nineteen patients (238 knees) with osteoarthritis who underwent staged bilateral primary TKA performed by a single surgeon were evaluated. The medical records of 15 males and 104 females were retrospectively reviewed. All variables were expressed as median (interquartile range). Results: The OT for all TKAs was 57 min (51, 65). The OT on the left side (59 min (52−67)) was longer than that on the right side (55 min (50−62)) (p = 0.015). Multiple regression analysis revealed that longer OT was related to BW (β = 0.488, p < 0.001), calendar year of surgery (β = −0.218, p< 0.001), and operative side (β = −0.151, p = 0.007). The Jonckheere−Terpstra test showed a trend toward decreasing OT with calendar year on the left side (p = 0.037) (surgeon’s non-dominant side), but not on the right (p = 0.795). Body height, BW, and body mass index showed weak correlations (r = 0.212, p = 0.001; r = 0.352, p < 0.001; r = 0.290, p < 0.001, respectively) with OT. Conclusion: Patients with a large physique, and especially obesity, with an affected knee on the surgeon’s non-dominant side may require a longer OT; OT decreased over time.

Do TKAs in Patients with Higher BMI Take Longer, and is the Difference Associated with Surgeon Volume? A Large-database Study from a National Arthroplasty Registry

BACKGROUND

Increased surgical time in TKA may impact economic costs and clinical outcomes. Prior work has found that TKAs in patients with high BMI take longer, and these patients may be at greater risk for postoperative complications like infection. However, these studies included small numbers of patients and surgeons from single institutions and they did not consider surgeon volume.

QUESTIONS/PURPOSES

Using the New Zealand Joint Registry (NZJR), we asked: (1) Is there a relationship between increasing patient BMI and TKA operative time? (2) Is the effect of BMI on surgical time less pronounced among surgeons who perform more TKAs per year than those who perform fewer?

METHODS

Data were collected from the NZJR between January 2010 and December 2018 as it is the only national registry that records both BMI and surgical time. Primary TKA performed for osteoarthritis by surgeons with more than 50 TKAs over the period of the study were identified. BMI and operative time (skin incision to closure in minutes) were recorded. Patients with the following were excluded: lateral parapatellar or minimally invasive approaches; navigated, patient-specific instrumentation, or robot-assisted TKA; uncemented or hybrid fixation; those with procedures performed by a trainee (all or part); or a nonosteoarthritic indication. Of 64,108 TKAs performed during the study period, a total of 42% (27,057) met our inclusion criteria. The primary outcome was the effect of BMI on operative time. Operative time is expressed in minutes as a mean for each single-unit BMI increase across all surgeons, controlled for other variables that might influence operative time such as patella resurfacing and cruciate-retaining versus posterior-stabilized designs. Overall, the mean operative time (skin incision to closure) was 79 ± 22 minutes. Surgical experience was assessed by subdividing surgeons into six groups according to the number of TKAs performed annually (< 10, 10 to 24, 25 to 49, 50 to 74, 75 to 99, and > 100). Statistical analyses were performed including a general linear model to assess the independent association between BMI and operative time, allowing for the effects of other patient and surgical features. In addition, linear regression analyses explored the associations between BMI and operative time in the whole group and within surgical volume groups.

RESULTS

There was an association between increasing BMI and increasing surgical duration. The mean operative time increased from 75 ± 22 minutes in patients with a normal BMI of 25 kg/m2 to 87 ± 24 minutes in patients with a BMI of 40 kg/m2 to 94 ± 28 minutes in patients with a BMI > 50 kg/m2 (p < 0.001). Surgeons performing fewer than 25 TKAs per year took 14% longer to perform a TKA on a patient with a BMI of 40 kg/m2 than on a patient with a normal BMI of 25 kg/m2. However, surgeons performing greater than 25 TKAs per year took 10% longer.

CONCLUSION

In this study, an increase BMI was associated with increased surgical time in TKA. Surgical duration for high-volume surgeons appears less influenced by increases in BMI than lower volume surgeons. Although the absolute increase in duration was small, prolonged surgical time may reduce theater productivity. Even though the issues around managing patients with high BMI are multifactorial and complex, considerations from these findings include ensuring appropriate theater scheduling and possibly referring patients with high BMI to specialist centers. Further studies should focus on assessing the effectiveness of such measures in reducing complications and improving outcomes in patients with elevated BMI.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Obesity, preoperative weight loss, and telemedicine before total joint arthroplasty: a review

The preoperative period prior to elective total joint arthroplasty (TJA) is a critical time for lifestyle interventions since a scheduled surgery may help motivate patients to lose weight. Weight loss may reduce complications associated with obesity following TJA and enable patients with severe obesity (body mass index [BMI] > 40 kg/m²) to become eligible for TJA, as many institutions use a 40 kg/m² cut-off for offering surgery. A comprehensive review was conducted to (1) provide background on complications associated with obesity following TJA, (2) synthesize prior research on the success rate of patients losing weight after being denied TJA for severe obesity, (3) discuss bariatric surgery before TJA, and (4) propose mobile health telemedicine weight loss interventions as potential weight loss methods for patients preoperatively. It is well established that obesity increases complications associated with TJA. In total knee arthroplasty (TKA), obesity increases operative time, length of stay, and hospitalization costs as well as the risk of deep infection, revision, and component malpositioning. Obesity may have an even larger impact on complications associated with total hip arthroplasty (THA), including wound complications and deep infection. Obesity also increases the risk of hip dislocation, aseptic loosening, and venous thromboembolism after THA. Synthesis of the only two studies (n = 417), to our knowledge, that followed patients denied TJA for severe obesity demonstrated that only 7% successfully reduced their BMI below 40 kg/m² via lifestyle modifications and ultimately underwent TJA. Unfortunately, bariatric surgery may only increase certain post-TKA complications including death, pneumonia, and implant failure, and there is limited research on preoperative weight loss via lifestyle modification. A review of short-term mobile health weight loss interventions that combined personalized counseling with self-monitoring via a smartphone app found about 5 kg of weight loss over 3-6 months. Patients with severe obesity have more weight to lose and may have additional motivation to do so before TJA, so weight loss results may differ by patient population. Research is needed to determine whether preoperative mobile health interventions can help patients become eligible for TJA and produce clinically significant weight loss sufficient to improve postoperative outcomes.

Effects of obesity on clinical and functional outcomes following anatomic and reverse total shoulder arthroplasty

BACKGROUND

Limited data exist regarding the clinical and functional outcomes following primary total shoulder arthroplasty in obese patients. The purpose of this study is to determine the effects of obesity on the clinical and functional outcomes following primary anatomic total shoulder arthroplasty (aTSA) and reverse total shoulder arthroplasty (rTSA) in a large patient population with mid-term follow-up.

METHODS

Patients in a multi-institutional shoulder registry receiving either primary aTSA (n = 1520) or rTSA (n = 2054) from 2004 to 2018 with a minimum follow-up period of 2 years were studied. All patients received the same single-platform shoulder prosthesis. Study groups were assigned based on implant type (anatomic or reverse), and further stratification was based on patient body mass index (BMI), with obese patients having a BMI ≥ 30 and non-obese patients having a BMI < 30. Patients were evaluated and scored preoperatively and at latest follow-up by use of 5 scoring metrics and range of motion (ROM).

RESULTS

The mean follow-up period was 5 years (range, 2-14 years). Obese patients comprised 41% of the aTSA group and 35% of the rTSA group. Significant postoperative improvements in visual analog scale pain scores, ROM, and all 5 scoring metrics occurred in both obese and non-obese patients (P < .05). Obese patients in both groups reported higher preoperative and postoperative visual analog scale pain scores and less preoperative and postoperative ROM compared with non-obese patients. Compared with non-obese patients, obese patients receiving aTSA reported significantly worse postoperative Simple Shoulder Test, Constant-Murley, American Shoulder and Elbow Surgeons, University of California, Los Angeles, and Shoulder Pain and Disability Index scores compared with non-obese patients, and those receiving rTSA reported significantly worse American Shoulder and Elbow Surgeons and Shoulder Pain and Disability Index scores (all P < .05). However, these differences did not exceed the minimal clinically important difference or substantial clinical benefit criteria. Radiographic analysis showed that in the rTSA group, obese patients had significantly less postoperative scapular notching and a lower scapular notching grade compared with non-obese patients (P < .05).

DISCUSSION

Both non-obese and obese patients can expect clinically significant improvements in pain, motion, and functional outcome scores following both aTSA and rTSA. Obese patients reported significantly more postoperative pain, lower outcome scores, and less ROM compared with non-obese patients after both aTSA and rTSA at a mean follow-up of 5 years. However, statistically significant differences were not found to be clinically significant with respect to established minimal clinically important difference and substantial clinical benefit criteria. Therefore, obese and non-obese patients experience similar clinical outcomes following total shoulder arthroplasty, regardless of BMI. However, obese patients have more comorbidities, greater intraoperative blood loss, and less scapular notching compared with non-obese patients.

Procedures With Longer Intraoperative Times Undervalue Surgeon Work in Total Joint Arthroplasty: A Large, Nationwide Database Study

BACKGROUND

Work relative value units (wRVUs) measure a surgeon's time and intensity required to perform the pre-service, intra-service, and post-service work of a surgical procedure and are commonly used to compare a physician's work between different procedures. Previous literature across multiple specialties report that longer, often revision, operations are undervalued when compared to primary procedures. Our study aims to analyze the differences in intra-operative time, and its corresponding wRVU/h between the Medicare benchmarks and real-world time-stamped data for total joint arthroplasty procedures.

METHODS

Thirteen primary and revision hip and knee arthroplasty procedures were identified, and intra-operative times were collected using the National Surgical Quality Improvement Program databases from 2014 to 2019. The Relative Value Scale Update Committee's (RUC) estimated median intra-operative times for each procedure was compared to the calculated median intra-operative times from National Surgical Quality Improvement Program, as were their corresponding wRVU/h. Procedures were additionally stratified by "long" (>110 minutes) and "short" (≤110 minutes) intra-operative times.

RESULTS

The RUC over-estimated intra-operative time by 35.24% on average and this overestimation was more profound in longer operations than shorter operations (47.75% vs 15.22%, P = .011). The RUC intensity per unit time values (wRVU/h) between "long" and "short" procedures were significantly different (P < .001) and showed the undervaluation of intensity for the longer procedures by an average of 3.47 wRVU/h.

CONCLUSION

Our study provides further evidence that physician work is undervalued in revision total hip and knee surgeries.

The Association of Body Mass Index with Surgical Time Is Mediated by Comorbidity in Patients Undergoing Total Hip Arthroplasty

Overweight represents a major issue in contemporary orthopaedic practice. A higher body mass index (BMI) is associated with an increase of perioperative complications following several orthopaedic procedures, in particular total hip arthroplasty (THA). However, the influence of overweight on THA surgical time is controversial. In this study, we investigated the association between BMI and surgical time analyzing the role of patients’ comorbidities. We conducted a retrospective study on 748 patients undergoing THA at our institutions between 2017 and 2018. Information regarding medical diseases was investigated and the burden of comorbidity was quantified using the Charlson score (CCI). Surgical time and blood loss were also recorded. Median surgical time was 76.5 min. Patients with surgical time above the median had both a higher BMI (28.3 vs. 27.1 kg/m²; p = 0.002); and CCI (1 vs. 0; p = 0.016). According to linear regression, surgical time was associated with BMI in the unadjusted model (p < 0.0001), after adjusting for age and sex (p < 0.0001), and in the multivariable model (p = 0.005). Furthermore, BMI was associated with increased surgical time only in patients with a Charlson score above the median, but not in others. Obesity is associated with increased surgical time during THA, especially in pluricomorbid patients, with a higher risk of perioperative complications.

Preoperative Nonsurgical Weight Loss Interventions Before Total Hip and Knee Arthroplasty: A Systematic Review

BACKGROUND

An upcoming total joint arthroplasty (TJA) may motivate patients with severe obesity (body mass index [BMI] > 40 kg/m²) to lose weight. Weight loss can optimize outcomes following TJA, and many surgeons use a 40 kg/m² cut-off for undergoing TJA to reduce the risk of complications. However, few patients who are denied TJA for severe obesity successfully lose weight. This is the first systematic review of nonsurgical weight loss interventions before TJA.

METHODS

Five electronic databases were searched for articles on January 11, 2021. Studies that utilized preoperative nonsurgical weight loss interventions for patients with obesity (BMI ≥ 30 kg/m²) scheduled for or awaiting TJA of the hip or knee were included. Two reviewers independently screened articles, assessed methodological quality, and extracted data.

RESULTS

We retrieved 1943 unique records, of which 7 met inclusion criteria including 2 randomized clinical trials and 5 single-arm case series. Overall, weight loss ranged from 5.0 to 32.5 kg. Four interventions reduced BMI by 3 kg/m² at 3-5 months, while 1 reduced BMI by 12.7 kg/m². Other weight outcomes and those related to pain, function, complications, and adverse events were inconsistently reported.

CONCLUSION

Although larger trials are needed, particularly randomized controlled trials that measure preoperative weight loss in a control group, nutritional status, and postoperative complications, the available evidence indicates that short-term, nonsurgical, preoperative weight loss interventions before TJA produce both statistically significant weight loss and reduced BMI before surgery. It remains unknown if the amount of weight loss from these interventions is clinically significant and sufficient to improve outcomes after TJA.

Greater risk of all-cause revisions and complications for obese patients in 3 106 381 total knee arthroplasties: a meta-analysis and systematic review

BACKGROUND

Obesity is a major public health issue and has considerable implications on outcomes of total knee arthroplasty (TKA). However, there has been conflicting evidence and conclusions on the effects of obesity on TKA. This meta-analysis compares the outcomes, complications, and peri-operative parameters of TKA in the obese (body mass index [BMI] ≥ 30 kg/m² ) versus non-obese (BMI < 30 kg/m² ) population as well as subgroup analysis of morbidly obese (BMI ≥ 40 kg/m² ) versus non-obese population.

METHODS

A meta-analysis was conducted with a multi-database search according to PRISMA guidelines on 12 September 2019. Data from all published literature meeting inclusion criteria were extracted and analysed.

RESULTS

Ninety-one studies were included, consisting of 917 447 obese and 2 188 834 non-obese TKA. Obese patients had higher risk of all-cause revisions (odds ratio [OR] = 1.15, 95% CI: 1.08-1.24, p < 0.0001), all complications (OR = 1.21, 95% CI: 1.06-1.38, p = 0.004), deep infections (OR = 1.47, 95% CI: 1.27-1.69, p < 0.0001), superficial infections (OR = 1.59, 95% CI: 1.32-1.91, p < 0.0001), wound dehiscence (OR = 1.46, 95% CI: 1.24-1.72, p < 0.0001) and readmissions (OR = 1.21, 95% CI: 1.05-1.40, p = 0.009). Subgroup analysis of morbidly obese patients revealed greater risks of all-cause revisions (OR = 1.25, 95% CI: 1.10-1.43, p = 0.0009), deep infections (OR = 1.98, 95% CI: 1.05-3.75, p = 0.04), superficial infections (OR = 2.44, 95% CI: 2.08-2.88, p < 0.0001) and readmissions (OR = 1.33, 95% CI: 1.20-1.47, p < 0.0001). No analysis was performed on patient reported outcome measures due to heterogeneous reporting methods.

CONCLUSION

Obese and morbidly obese patients have higher risks of revisions and infections post TKA. Surgeons should counsel patients of these risks during the informed consenting process and adopt preventative strategies into clinical practice to reduce risks where possible. In conclusion, obesity is a significant, modifiable risk factor for increased complications following TKA.

Is Obesity Associated with Higher Complication Rates in Total Hip Arthroplasty for High-Riding Dysplastic Hips?

OBJECTIVE

Developmental dysplasia of the hip (DDH) is a disabling pathology leading to hip problems, such as painful arthritic hip, unstable hip, etc. Total hip arthroplasty (THA) is an effective treatment modality for this condition. Obesity has been shown to be associated with increased rates of complications following orthopaedic surgeries (Journal of Arthroplasty 20:46-50). The hypothesis of this study was that patients with a body mass index (BMI) greater than 30 (obese), who undergo total hip arthroplasty for dysplastic hip, are associated with longer operative and anaesthetic times, longer hospital stays and higher re-admission rates within 30 days.

METHODS

All the cases of total hip arthroplasty in patients with high-riding dysplastic hips were reviewed. Evaluation was made of a total of 68 patients comprising 64 females and 4 males, classified into two groups. Patients with BMI < 30 kg/m2 formed the non-obese group and patients with BMI ≥ 30 kg/m2 the obese group.

RESULTS

The mean age was 44.67 ± 6.49 years. BMI was < 30 in 44 (64.7%) patients and > 30 in 24 (35.3%) patients. The data analysis showed that mean surgical time, anaesthesia duration and re-admission rate were significantly higher in the group with BMI ≥ 30(obese) as compared to the group with BMI < 30 (non-obese) (p < 0.01). The complication rate was determined to be higher in the obese group (p < 0.05).

CONCLUSION

Obese patients performed with total hip arthroplasty for high-riding dysplastic hips had more complications and higher rates of re-admission to hospital compared with the non-obese patients.

Operative Times in Primary Total Knee Arthroplasty: Can We Predict the Future Based on Contemporary Nationwide Data

Recently, the Centers for Medicare & Medicaid Services announced its decision to review "potentially misvalued" Current Procedural Terminology (CPT) codes, including those for primary total knee arthroplasty (TKA). CPT 27447 is being reevaluated to determine contemporary relative value units for work value, with operative time considered a primary factor in this revaluation. Despite broader indications for TKA, including extension of the procedure to more complex patient populations, it is unknown whether operative times may remain stable in the future. Therefore, the purpose of this study was to specifically evaluate future trends in TKA operative times across a large sample from a national database. The American College of Surgeons National Surgical Quality Improvement Project database was queried from January 1, 2008 to December 31, 2017 to identify 286,816 TKAs using the CPT code 27447. Our final analysis included 140,890 TKAs. Autoregressive integrated moving average forecasting models were built to predict 2- and 10-year operative times. While operative times were significantly different between American Society of Anesthesiologists (ASA) classes 1 and 2 (p = 0.035), there were not enough patients in ASA class 1 to perform rigorous inference. Additionally, operative times were not significantly different between ASA classes 3 and the combined ASA classes 4 and 5 cohort (p = 0.95). Therefore, we were only able to perform forecasts for ASA classes 2 and 3. Operative time was found to be nonstationary for both ASA class 2 (p = 0.08269) and class 3 (p = 0.2385). As a whole, the projection models indicated that operative time will remain within 2 minutes of the present operative time, up to the year 2027. Our projections indicate that operative times will remain stable over the next decade. This suggests that there is a lack of evidence for reducing the valuation of CPT code 27477 based on intraservice time for TKA. Further study should examine operative time trends in the setting of evolving alternative payment models, increasing patient complexity, and governmental restrictions.

Complication rates and resource utilization after total hip and knee arthroplasty stratified by body mass index

Over 295,000 patients from 2016 to 2018 in a national database were grouped into normal weight (BMI 18.5 to <25 kg/m²), overweight (25 to <30), type-1 obese (30 to <35), type-2 obese (35 to <40), and type-3 obese (40 or higher). Differences in resource utilization and complication rates across BMI categories were compared. In comparison to normal weight patients, overweight and obese patients undergoing TJA were at risk for increased resource utilization and various early complications. Patients undergoing TKA with a BMI up to 45 kg/m² are at similar risk for 30-day postoperative complications when compared to type-1 obese patients.

Increased Operative Time Impacts Rates of Short-Term Complications After Unicompartmental Knee Arthroplasty

BACKGROUND

Previous evidence has demonstrated an exacerbating effect of increased operative time on short-term complications in total joint arthroplasty. While the same relationship may be expected for unicompartmental knee arthroplasty (UKA), supporting evidence remains sparse. The purpose of this study is to determine the impact of operative time on short-term complication rates after UKA and determine a critical threshold in operative times after which complications may increase.

METHODS

The American College of Surgeons National Surgical Quality Improvement Project was queried from 2007 to 2018 to identify 11,633 UKA procedures that were included in the final analysis. The effect of operative time on complications within 30 days was evaluated using multivariate logistic regression models. Receiver operating characteristics curves and spline regression models were used to identify critical thresholds in operative time that increase the likelihood of short-term complications.

RESULTS

Longer operative times (in minutes) were associated with higher rates of surgical site infection (90.4 ± 26.7 vs 84.8 ± 25.5, P = .003), blood transfusions (94.9 ± 28.6 vs 84.9 ± 25.5, P = .007), as well as reoperation rates (90.8 ± 27.9 vs 84.9 ± 25.5, P = .01), extended hospital length of stay (93.4 ± 29.8 vs 84.5 ± 25.2, P < .001), and mortality (110.4 ± 35.5 vs 84.9 ± 25.5, P = .008). Following multivariate logistic regression, operative time was found to independently predict increased surgical site infection, blood transfusion, myocardial infarction, extended length of stay, and mortality (odds ratio: 1.09 - 1.45, CI: 1.01 - 1.91, all P values <0.02). Receiver operating characteristics curves found an increase in mortality risk during the 30-day postoperative period after 88.5 minutes of operative time, a finding supported by spline regression plots.

CONCLUSION

The present study found a positive correlation between increased operative times and short-term postoperative complication rates after UKA. Despite a statistically significant association with increasing operative time, odds ratios of reported complications are relatively low.

The Effect of Obesity on Operating Room Utilization in Breast Surgery

BACKGROUND

The current obesity epidemic is associated with increased health care costs associated with comorbidities such as diabetes and heart disease as well as postoperative complications. However, the effect of obesity on operating room (OR) utilization, especially in common breast procedures, has not been completely evaluated. Our study is the first to examine the effect of patient obesity on operative time (OPT) for common breast procedures.

METHODS

The American College of Surgeons National Surgical Quality Improvement Project databases for 2010-2018 were searched for this retrospective review. Patients undergoing common breast operations (lumpectomy, lumpectomy with sentinel lymph node biopsy (SLNB) (+/- injection), lumpectomy and axillary lymph node dissection (ALND), simple mastectomy, mastectomy with SLNB (+/- injection), and mastectomy with ALND) were filtered out by Current Procedural Terminology code and divided into three groups based on their body mass index (BMI) and weight. Using the two-sample t-test, OPT for the procedures was compared among the lowest and highest BMI and weight categories. We also used a linear regression t-test to demonstrate that for every unit increase in BMI, there was a corresponding increase in OPT for each procedure.

RESULTS

When the lowest and highest BMI and weight groups were compared, significant differences in OPT (P < 0.0001) were seen for each of the procedures. Numerous factors that could affect the complexity of surgery and thus OR time were identified. The correlation between BMI and weight and OPT remained significant after controlling for these variables. The differences between the highest and lowest BMI groups were most pronounced for higher complexity procedures, such as lumpectomy with ALND and mastectomy with ALND, with average operating times increasing by 18.2 min and 18.6 min, respectively, for patients with a higher BMI.

CONCLUSIONS

Patient BMI and weight significantly affect OPT for common breast procedures. Therefore, patient BMI should be taken into account to improve OR scheduling.

The Effect of Obesity on Operative Time and Postoperative Complications for Peritrochanteric Femur Fractures

Introduction The high prevalence of obesity among adults in the United States presents significant challenges to orthopedic surgeons. Obesity has been shown to increase operative time and complications in both elective and nonelective orthopedic surgeries. Despite this, there is a lack of literature evaluating the effect obesity has on operative time and postoperative complications following peritrochanteric fracture surgery. Methods and Materials We performed a retrospective review of patients who underwent isolated operative stabilization of a peritrochanteric femur fracture at our urban level one trauma center between 2010 and 2018. Patients were divided into an obese group, as defined by a body mass index (BMI) equal to or greater than 30 kg/m2, and a nonobese group, as defined by a BMI less than 30 kg/m2. Operative timing variables including time to surgery, operative time, total operating room (OR) time, anesthesia time, and fluoroscopy time were collected. Postoperative variables evaluated including the presence of a major postoperative complication within 90 days of surgery, the need for repeat surgery within 90 days, and the need for surgery due to an infection within 90 days were collected. Results A total of 175 patients were included in this retrospective review. Thirty-seven patients were included in the obese group, and 138 were included in the nonobese group. Obesity was associated with a significantly (p = 0.002) longer operative time, total OR time (p = 0.0001), anesthesia time (p = 0.00006), and fluoroscopy time (p = 0.0001). There was no significant difference (p > 0.05) in postoperative variables between the obese and nonobese group. The 90-day major postoperative complication rate was 10.8% in the obese group and 10.9% in the nonobese group. Both repeat surgery and surgery for infection within 90 days were 2.7% in the obese group and 1.4% in the nonobese group. Conclusion The treatment of peritrochanteric femur fractures in obese patients is associated with a significantly longer operative time, total OR time, anesthesia time, and fluoroscopy time, but no difference in major postoperative complications when compared to nonobese patients.

Elevated BMI is associated with intra-articular comminution, prolonged operative time, and postoperative complications in distal radius fractures

INTRODUCTION

Obesity continues to be a problem in the United States with greater than 35% of the adult population affected. Obesity influences fracture care as it affects impact forces, alters cellular pathways of healing, and is often associated with higher complication rates. Distal radius fractures are among the most common fracture patterns in the adult population. The purpose of this study was to evaluate the effect of BMI on the degree of intra-articular fracture comminution, operative time, and return to the OR in obese patients who underwent operation for distal radius fractures.

METHODS

A retrospective analysis of the American College of Surgeons National Surgical Improvement Program's (ACS-NSQIP) database was performed and logistic regressions were used to assess the relationship between BMI and open treatment of distal radius fractures. Three separate CPT codes were used to distinguish between extra-articular fractures, intra-articular split fracture, and intra-articular fracture with comminution. Percutaneous or closed treatment of distal radius fractures were excluded.

RESULTS

A total of 11,228 patients (mean age 65.1 years) with open reduction and internal fixation of distal radius fractures were identified. For every increase in BMI point, there was an increased risk of intra-articular split fracture by 1.7% (OR 1.017, 95% CI 1.010-1.023, p < 0.01) and increased risk of intra-articular comminution by 3.1% (OR 3.1, 95% CI 1.025-1.037, p < 0.01). Additionally, for every increase in BMI point, the risk of a surgical complication increased by 2.3% DISCUSSION: This nationally representative, population-based study demonstrates that elevated BMI is associated with increased risk for intra-articular involvement and higher risk for post-operative complications. Our results can be useful to patients and orthopedic surgeons as prognostic information for counseling patients on expectations following open reduction and surgical fixation of distal radius fractures.

LEVEL OF EVIDENCE

Case-control study. Level III.

Soft Tissue Radiological Knee (SToRK) Index: An observational cohort study to produce an index that quantifies the magnitude of soft tissue around the knee using standard radiographs

INTRODUCTION

The soft tissue envelope around the knee can have an impact on the ease of performing surgery such as total knee replacement (TKR). BMI is often used in planning theatre time but may be a poor indicator of the soft tissue around the knee due to varying distribution of adipose tissue. Radiological images directly show the soft tissue. We therefore aim to develop a method of quantifying the soft tissue envelope around the knee using radiographs.

METHOD

Plain weight-bearing radiographs were used to measure the total knee (soft tissue and bony) width at the level of the epicondyles of the knee and the bony epicondylar width of the femur. The ratio of the two widths was defined as the Soft Tissue Radiological Knee (SToRK) Index. The validity of the index as a true measure of soft tissue envelope was assessed using cross sectional areas on axial MRI cuts at the level of the epicondyles. The inter-observer reliability was assessed using the intra-class correlation coefficient. SToRK Index values were correlated with patients' BMI, gender and operative time.

RESULTS

The results show there is a close correlation between the ratio of cross sectional area of MRI axial cuts at the level of epicondyles and the ratio of linear widths measured on plain radiographs, validating the SToRK Index as a measure of soft tissue envelope. There was also good to excellent inter-rater reliability of measurements of these widths. There was a close correlation between BMI and SToRK Index with differences between men and women.

DISCUSSION

We believe the SToRK Index is a validated method of quantifying soft tissue distribution around the knee and gives surgeons a better descriptor of the knee envelope than BMI. It is easy to use, needs simple investigations and is reproducible.

Have Total Hip Arthroplasty Operative Times Changed Over the Past Decade? An Analysis of 157,574 Procedures

BACKGROUND

With the recent reevaluation of surgeon reimbursement for total hip arthroplasty (THA) by the Centers for Medicare and Medicaid Services, there is increasing need for information regarding trends in operative time. While single-institutional analyses exist, there is a lack of large-scale, nationally representative, multi-institutional data. Therefore, the purpose of our study is to (1) evaluate past/present operative time trends for THA and (2) investigate factors influencing operative times from a 10-year, large multi-institutional database.

METHODS

All primary THAs conducted between 2008 and 2018 were queried using Current Procedural Terminology code 27130 from the American College of Surgeons-National Surgical Quality Improvement Program database, yielding 157,574 patients. Operative time, demographics, and comorbidity data were collected and analyzed. Multivariable linear models were created, and trend analyses were used where appropriate.

RESULTS

Median operative time was 87 minutes. Operative time was stable across included study years, with all calculated values within 5 minutes of the median (range, 86-92 minutes). Operative time was statistically stable over the last 3 years (P = .121). Age, body mass index, resident involvement, modified Charlson comorbidity index, and preoperative laboratory values influenced operative time (P < .001). Length of stay, readmission, superficial wound infection, and sepsis decreased over the study period. Nonelective procedures were statistically longer than elective (P < .0001).

CONCLUSION

While numerous factors influence the duration of THA, this study found that THA operative time has remained stable in recent years. Therefore, revaluation for THA based on intraservice time is not supported. Future analyses should continue to analyze factors that influence operative time in order to ensure patient safety and maintain positive outcomes.

Do Patient Point of Entry and Medicaid Status Affect Quality Outcomes Following Total Knee Arthroplasty?

BACKGROUND

The effect of surgeon practice and patient care setting have not been studied in the Medicaid population undergoing total knee arthroplasty (TKA). This study aims to evaluate whether point of entry and Medicaid status affect outcomes following TKA.

METHODS

The electronic medical record at our urban, academic, tertiary care hospital system was retrospectively reviewed for all primary, unilateral TKA during January 2016 and January 2018. Outpatient visits within the 6-month preoperative period categorized TKA recipients as either Hospital Ambulatory Clinic Centers patients with Medicaid insurance or private office patients with non-Medicaid insurers.

RESULTS

There were 174 Medicaid patients and 317 non-Medicaid patients for 491 total patients. Medicaid patients were significantly younger (62.6 ± 1.6 vs 65.4 ± 1.1 years, P < .01), of "other' ethnicity (43.1% vs 25.6%, P < .01), and to be a current smoker (9.3% vs 6.6%, P = .02). There was no difference in gender, body mass index, and American Society of Anesthesiologists score. After controlling for patient factors, the Medicaid effect was insignificant for surgical time (exponentiated β 0.93, 95% confidence interval [CI] 0.86-1.01, P = .076) and facility discharge (odds ratio 1.58, 95% CI 0.71-3.51, P = .262). Medicaid status had a significant effect on length of stay (LOS) (rate ratio 1.21, 95% CI 1.02-1.43, P = .026).

CONCLUSION

Multivariable analysis controlling for patient factors demonstrated that Medicaid coverage had minimal effect on surgical time and facility discharge. Medicaid patients had significantly longer LOS by one-half day. These results indicate that comparable outcomes can be achieved for Medicaid patients following TKA provided that the surgeon and care setting are similar. However, increased care coordination and preoperative education may be necessary to normalize disparities in hospital LOS.

LEVEL OF EVIDENCE

III, retrospective observational analysis.

Predictive factors for longer operative times in patients with medial knee osteoarthritis undergoing total knee arthroplasty

BACKGROUND

Prolonged operative time has frequently been implicated as a risk factor for various complications after total knee arthroplasty (TKA). We aimed to determine whether preoperative factors such as sex, age, body mass index (BMI), prosthetic design, tibiofemoral angle (TFA), range of motion, coronal laxity, Hospital for Special Surgery score and periarticular bone mineral density (BMD) affect operative time.

METHODS

We evaluated 164 patients (187 knees) with medial osteoarthritis who underwent primary TKA performed by a single surgeon. The medical records of 27 males and 137 females (median age of 77 and 72 years, respectively) were retrospectively reviewed. TFA was measured on non-weightbearing, standard radiographs. We used dual-energy X-ray absorptiometry to measure BMD, and an arthrometer to evaluate total coronal laxity in each patient.

RESULTS

According to univariate analyses, there was a weak positive correlation between BMI and operative time (r = 0.265, p < 0.001), between TFA and operative time (r = 0.235, p = 0.001) and between BMD of the femur and tibia and operative time (r = 0.280, p < 0.001, r = 0.286, p < 0.001, respectively). No significant correlations were found between the other factors and operative time. Based on multivariate analyses, only BMD of the tibia and TFA were significantly correlated with operative time (β = 0.418, p < 0.001 and β = 0.182, p = 0.007, respectively).

CONCLUSIONS

TFA and BMD of the tibia were the variables more strongly correlated with operative time. Surgeons should recognize preoperatively that patients who have increased TFA, higher periarticular BMD, and higher BMI may have longer operative times.

LEVEL OF EVIDENCE

Level IV retrospective study.

Periprosthetic knee infection reconstruction with a hinged prosthesis: Implant survival and risk factors for treatment failure

BACKGROUND

Severe bone and soft tissue defects are common after failed two-stage exchange arthroplasty for periprosthetic joint infection (PJI). There is a paucity of evidence on the outcomes of using a hinged prosthesis for knee PJI reconstruction during second-stage re-implantation, especially regarding implant survivorship, reinfection risk factors, and functionality after successful reconstruction.

METHODS

A total of 58 knee PJI patients with Anderson Orthopaedic Research Institute (AORI) type II/III defect and soft tissue insufficiency underwent reconstruction with hinged prosthesis. Enrolled patients adhered to a two-stage exchange arthroplasty protocol and were evaluated for a mean follow up of 65.1 months. Kaplan-Meier analysis was conducted for implant survivorship and infection-free survival. Multivariate analysis was used to determine independent risk factors for recurrent infections. Knee Society Score (KSS) was used to evaluate functional outcomes.

RESULTS

The survivorship of hinged prosthesis was 86.2% at 2 years and 70.2% at 5 years. Infection-free analysis revealed an estimation of 68.9% at 2 years and 60.6% at 5 years. Of the 58 patients, 13 (22.4%) developed recurrent PJI, three (5.2%) aseptic loosening, and one (1.7%) periprosthetic fracture. Multivariate analysis revealed that obesity (hazard ratio (HR), 3.11), high-virulent pathogen (HR, 3.44), and polymicrobial infection (HR, 3.59) were independent risk factors for reinfection. Patients showed a mean improvement of 32.8 ± 7.7 in Knee Society Clinical Score (KSCS) and 30.8 ± 11.0 in Knee Society Function Score (KSFS) after successful reconstruction (P<0.001).

CONCLUSIONS

Using hinged knee prosthesis for PJI reconstruction provided an overall implant survival of 70.2% and an infection-free survival of 60.6% at mid-term follow up. Obesity, virulent pathogens, and polymicrobial infections were independent risk factors for infection recurrence.

BMI is a Better Predictor of Periprosthetic Joint Infection Risk Than Local Measures of Adipose Tissue After TKA

BACKGROUND

Both body mass index (BMI) and local measures of adiposity at the surgical site have been identified as independent risk factors for periprosthetic joint infection (PJI) (periprosthetic joint infection) after total knee arthroplasty (TKA). We aimed to 1) evaluate previously used measures of assessing knee adiposity and 2) determine the best measure for predicting both surgical duration and PJI after TKA.

METHODS

We performed a multicentre retrospective review of 4745 patients who underwent primary TKA between January 2013 and December 2016. Patient demographic information, surgical duration and postoperative infection status within one year were obtained. Preoperative weight-bearing AP and lateral x-rays were analyzed to determine prepatellar adipose thickness, bony width of the tibial plateau, and total soft tissue knee width. The knee adipose index (KAI) was calculated from the ratio of bone to total knee width.

RESULTS

We observed substantial variability in both local measures of adiposity compared with BMI. Neither measure of local knee adipose showed a significant correlation with PJI risk. By contrast, there was a strong correlation between PJI risk and BMI >35 (odds ratio 2.9, 95% CI 1.4-6.1). Surgical duration increased with both BMI and measures of local adipose tissue (KAI and prepatellar fat thickness).

CONCLUSION

Local adipose deposition varies greatly for any given BMI. In this study, BMI was a better predictor of PJI after TKA than local measures of knee adipose tissue.

The influence of obesity on clinical outcomes following primary total knee arthroplasty: A prospective cohort study

BACKGROUND

The aim of this study was to evaluate the influence of obesity on patients' function, pain, and complications following primary total knee arthroplasty (TKA) with an enhanced-recovery program.

METHODS

A total of 157 patients were enrolled into a prospective study and assigned into one of three groups on the basis of their body mass index (BMI): normal (BMI 18.0-24.9 kg/m²), overweight (BMI 25.0-29.9 kg/m²), or obese (BMI ≥30.0 kg/m²). The primary outcome was knee range of motion (ROM) on postoperative day (POD) 3, 15, 30, and 90, and secondary outcomes were visual analog scale (VAS) on POD 1, 2, 3, 15, 30, and 90, length of stay, and complications.

RESULTS

The ROM of patients in the obese group on POD 3 was higher than in the normal (104.4 ± 8.5 vs. 98.9 ± 8.9, P = .010) and overweight (104.4 ± 8.5 vs. 97.7 ± 7.8, P = .001) groups. Similarly, the VAS in the obese group at rest on POD 1 was lower than in the normal (2.0 ± 0.7 vs. 2.2 ± 0.6, P = .043) and overweight (2.0 ± 0.7 vs. 2.3 ± 0.6, P = .010) groups. In addition, the incidence of complications did not differ significantly among the three groups, but the length of hospital stay in the obese group was longer (P = .027).

CONCLUSIONS

Obesity may not affect patients' function and pain, and may not increase the incidence of complications following primary TKA. Obese patients may obtain satisfactory functional rehabilitation outcomes, but with a longer duration of rehabilitation.

Multimodal Conservative Treatment of Complicated Open Wound After Total Knee Replacement Arthroplasty in Patients With Comorbidities

Total knee replacement arthroplasty is a common procedure and postoperative wound complications are sometimes inevitable. Although invasive reconstructive surgery may be an option for nonhealed wounds, such procedures can limit early rehabilitation, adversely affecting the range of joint motion. Patients can achieve a wider range of motion if they undergo early rehabilitation with a conservative approach. From 2015 to 2017, 5 patients with comorbidities who underwent total knee replacement arthroplasty were referred to the reconstructive surgery department for nonhealed open wounds. Depending on their comorbidities and conditions, the patients underwent negative-pressure wound therapy based on multimodal conservative treatment. During the treatment, the patients continued rehabilitation. In the 5 patients, the mean duration of complete wound healing was 65.2 days (range = 57-81), during which all open wounds were well healed. For final wound closure, the patients underwent skin grafting, dermatotraction, or collagen dressing. Four patients achieved ranges of joint motion over 100 degrees after treatment. We believe that early coverage is important for open wounds. For complicated open wounds after total knee replacement arthroplasty in patients with comorbidities, less invasive multimodal treatment along with early rehabilitation may be more effective to achieve adequate final range of joint motion.

What Factors Influence Operative Time in Total Knee Arthroplasty? A 10-Year Analysis in a National Sample

BACKGROUND

Changes in reimbursement in total knee arthroplasty (TKA) by Centers for Medicare and Medicaid Services (CMS) have been tied to a perceived decrease in the total surgical time required to perform these operations. However, little information is available to CMS about recorded surgical times for TKA across the United States and the variables that drive these values. Therefore, the purpose of our study, is to evaluate (1) changes in operative time over time and (2) factors associated with variations in operative time.

METHODS

The National Surgical Quality Improvement Program database was queried to identify all primary TKAs conducted between January 1, 2008, and December 31, 2017. All TKAs conducted within our study period that had operative time data available were included. Multivariable linear models were created to assess factors that influence operative time over the study period.

RESULTS

Our final analysis included 140,890 TKAs. The mean operative time across the study period was found to be 92.60 minutes. Examining quarterly values, operative time stayed within 5 minutes of this mean (range, 89.80-97.51 minutes). Age, sex, functional status, anesthesia type, body mass index, operative year, transfusion requirements, and preoperative laboratory findings significantly influenced operative time (P < .05 for all).

CONCLUSION

Our analysis indicates that while there are numerous factors that influence procedure duration, operative times have remained stable. This information should be heavily considered in regard to physician reimbursement, because providers are maintaining operative times and work effort while mitigating factors that influence outcomes in the perioperative period.

Knee joint distraction in regular care for treatment of knee osteoarthritis: A comparison with clinical trial data

Objectives

Knee joint distraction (KJD) has been evaluated as a joint-preserving treatment to postpone total knee arthroplasty in knee osteoarthritis patients in three clinical trials. Since 2014 the treatment is used in regular care in some hospitals, which might lead to a deviation from the original indication and decreased treatment outcome. In this study, baseline characteristics, complications and clinical benefit are compared between patients treated in regular care and in clinical trials.

Methods

In our hospital, 84 patients were treated in regular care for 6 weeks with KJD. Surgical details, complications, and range of motion were assessed from patient hospital charts. Patient-reported outcome measures were evaluated in regular care before and one year after treatment. Trial patients (n = 62) were treated and followed as described in literature.

Results

Patient characteristics were not significantly different between groups, except for distraction duration (regular care 45.3±4.3; clinical trials 48.1±8.1 days; p = 0.019). Pin tract infections were the most occurring complication (70% regular care; 66% clinical trials), but there was no significant difference in treatment complications between groups (p>0.1). The range of motion was recovered within a year after treatment for both groups. WOMAC questionnaires showed statistically and clinically significant improvement for both groups (both p<0.001 and >15 points in all subscales) and no significant differences between groups (all differences p>0.05). After one year, 70% of patients were responders (regular care 61%, trial 75%; p = 0.120). Neither regular care compared to clinical trial, nor any other characteristic could predict clinical response.

Conclusions

KJD as joint-preserving treatment in clinical practice, to postpone arthroplasty for end-stage knee osteoarthritis patient below the age of 65, results in an outcome similar to that thus far demonstrated in clinical trials. Longer follow-up in regular care is needed to test whether also long-term results remain beneficial and comparable to trial data.

No Evidence to Support Lowering Surgeon Reimbursement for Total Joint Arthroplasty Based on Operative Time: An Institutional Review of 12,567 Cases

BACKGROUND

The Centers for Medicare and Medicaid Services has recently added primary total joint arthroplasty (TJA) codes to the 2019 Potentially Misvalued Codes List. The American Association of Hip and Knee Surgeons and the American Medical Association have called for contemporary data that would assess operative time to inform the decision on reimbursement valuation. Therefore, the purpose of this study was to report total hip arthroplasty (THA) and total knee arthroplasty (TKA) operative times within a large multihospital and physician organizational enterprise to assess stability over time.

METHODS

The study was a retrospective review (2015-2019) of a prospectively maintained multihospital health system database. A total of 12,567 consecutive TJAs were included (5742 THAs by 16 surgeons; 6825 TKAs by 20 surgeons). Operative time was between incision and completion of wound closure. Descriptive statistics were performed for categorical/continuous variables, and trend analysis was performed to assess if there was a change in time over the study period.

RESULTS

For THA, 43.1% were male, with a mean age of 64.1 ± 11.8 years and a mean BMI of 30.1 ± 6.6. The mean operative time was 96.4 ± 36.8 minutes. For TKA, 39.4% were male, with a mean age of 66.2 ± 9.4 years and a mean BMI of 32.7 ± 6.8. The mean operative time was 103.6 ± 29.9 minutes. Trend analysis demonstrated no significant difference in operative time across the study period.

CONCLUSION

Our analysis demonstrated that operative time has remained stable, with mean time for THA and TKA consistently within 3.6 minutes of the historical benchmark of 100 minutes. Given these findings in a large institutional cohort, there is no definitive evidence to support changing current procedural valuation for TJA based on operative time.

Higher body mass index is not a risk factor for in-hospital adverse outcomes following total knee arthroplasty

PURPOSE

To investigate the association between body mass index (BMI) and perioperative complications until hospital discharge, following primary total knee arthroplasty (TKA).

METHODS

This retrospective study reviewed 1665 cases of elective primary unilateral TKA performed between 2006 and 2010, from a prospective secure electronic database. Types of complications, length of operating time, and duration of hospital stay were analyzed in both adjusted (for known confounders) and unadjusted analyses. A further matched analysis was also performed.

RESULTS

In terms of overall complications, there was no statistically significant difference between the BMI categories. When individual obesity category was considered, obese 2 had the lowest odds of developing complications, both with unadjusted (odds ratio (OR): 0.61, 95% confidence interval (CI) 0.41-0.91, p < 0.015) and adjusted regression analysis (OR: 0.65, 95% CI: 0.43-0.99, p = 0.044). Compared to normal weight category, obese class 3 (≥40 kg/m²) individuals were at 66% (OR: 0.34, 95% CI: 0.21-0.55) lower (unadjusted) odds of developing cardiac complications (overall p < 0.001). With the matched analysis, compared to normal weight category, obese class 3 (≥40 kg/m²) individuals were at a 60% (OR: 0.40, 95% CI: 0.23-0.68) lower (unadjusted) odds of developing cardiac complications (overall p = 0.004). Obese 3 patients had significantly higher operating time compared with other groups ( p < 0.001).

CONCLUSION

This study did not find a significant association between BMI and increased overall in-hospital medical or surgical complications following primary TKA. Obesity significantly increased the length of operating time.

Robotic-assisted unicompartmental knee replacement offers no early advantage over conventional unicompartmental knee replacement

PURPOSE

Unicompartmental knee arthroplasty (UKA) is effective for treating degenerative joint disease in a single compartment. Robotic-arm-assisted arthroplasty (RAA) has gained popularity and has theoretical benefits of improved outcomes over conventional (CONV) UKA due to the technical precision of bone preparation. This study compares the short-term clinical outcomes, including survivorship and patient-reported functional outcomes, for a series of medial UKAs performed with RAA and CONV.

METHODS

One hundred seventy-six consecutive fixed-bearing medial UKAs were retrospectively identified with a minimum follow-up of 2 years. One hundred and eighteen CONV and 58 RAA were performed. Pre- and post-operative SF12, WOMAC, and KSS Functional Questionnaires were available for all patients.

RESULTS

At 2 years, both groups improved in all functional outcomes, with no significant difference between the RAA and CONV cohorts. However, the RAA cohort had a significantly longer operative time (p < 0.001) and a higher early revision rate than the CONV group (7 [12.0%] vs. 7 [6.8%]; p < 0.05).

CONCLUSIONS

These results demonstrate that at short-term follow-up of 2 years, RAA was not superior to CONV in terms of functional scores and instead was associated with greater operative time and cost and lower survivorship. Therefore, at this time usage of RAA in UKA is not recommended compared to conventional UKA. Longer term studies are necessary to draw conclusions about the overall outcomes of RAA compared to CONV.

LEVEL OF EVIDENCE

III.

Is Operative Time a Predictor for Post-Operative Infection in Primary Total Knee Arthroplasty?

BACKGROUND

The purpose of this study is to identify factors affecting operative times and to evaluate the associations of operative times with prosthetic joint infections (PJIs) and surgical site infections (SSIs) in primary total knee arthroplasty.

METHODS

A total of 11,840 primary total knee arthroplasties with a mean 2-year post-operative follow-up were studied. Operative times were analyzed both as categorical and continuous variables. Associations with PJIs and SSIs were evaluated with univariate and multivariate analyses to adjust for gender, age, body mass index, Charlson Comorbidity Index, year of surgery, antibiotic cement use, and hospital/surgeon volume.

RESULTS

The longest cases (>121 minutes) were associated with patients who were younger (P < .001) and had a higher body mass index (P < .001). PJI rates were higher in cases >121 minutes (1.4%) compared to those <85 minutes (0.3%, P < .001). SSI rates were also highest (3.8%) in cases >121 minutes (P < .001). Cases complicated by PJIs (135 ± 47 minutes) had longer mean operative times compared to non-infected cases (105 ± 32 minutes, P < .001). Patients with subsequent SSIs also had longer mean operative times (P < .001). Multivariate analyses revealed an 18% increased risk for PJIs and an 11% increased risk for SSIs for every 15-minute increase in operative time.

CONCLUSION

Identifying risk factors for infection that are as easily measurable and modifiable as procedure duration can aid in risk-stratifying post-operative surveillance. This study demonstrated that longer operative times were an independent predisposing factor for both PJIs and SSIs even after accounting for patient and procedure-related factors.

Longer Operative Time Results in a Higher Rate of Subsequent Periprosthetic Joint Infection in Patients Undergoing Primary Joint Arthroplasty

BACKGROUND

Whether prolonged operative time is an independent risk factor for subsequent surgical site infection (SSI) and periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) remains a clinically significant and underexplored issue. The aim of this study is to investigate the association between operative time and the risk of subsequent SSI and PJI in patients undergoing primary TJA.

METHODS

We retrospectively reviewed 17,342 primary unilateral total knee arthroplasty and total hip arthroplasty performed at a single institution between 2005 and 2016, with a minimum follow-up of 1 year. A multivariate logistic regression model was conducted to identify the association between operative time and the development of SSI within 90 days and PJI within 1 year.

RESULTS

Overall, the incidence of 90-day SSI and 1-year PJI was 1.2% and 0.8%, respectively. Patients with an operative time of >90 minutes had a significantly higher incidence of SSI and PJI (2.1% and 1.4%, respectively) compared to cases lasting between 60 and 90 minutes (1.1% and 0.7%), and those lasting ≤60 minutes (0.9% and 0.7%, P < .01). In the multivariate model, the risk for infection increased by an odds ratio of 1.346 (95% confidential interval 1.114-1.627) for 90-day SSI and 1.253 (95% confidential interval 1.060-1.481) for 1-year PJI for each 20-minute increase in operative time.

CONCLUSION

In patients undergoing primary TJA, each 20-minute increase in operative time was associated with nearly a 25% increased risk of subsequent PJI. We advocate that surgeons pay close attention to this underappreciated risk factor while maintaining safe operative practices, which minimize unnecessary steps and wasted time in the operating room.

Efficacy and reliability of active robotic-assisted total knee arthroplasty compared with conventional total knee arthroplasty: a systematic review and meta-analysis

Background

In the field of prosthetics, the ultimate goal is to improve the clinical outcome by using a technique that prolongs the longevity of prosthesis. Active robotic-assisted total knee arthroplasty (TKA) is one such technique that is capable of providing accurate implant position and restoring mechanical alignment. Although relevant studies have been carried out, the differences in the efficacy and reliability between active robotic-assisted TKA and conventional arthroplasty have not yet been adequately discussed.

Methods

We referenced articles, including randomised controlled trials and comparative retrospective research, from PubMed, Embase, Cochrane Library and Web of Science, in order to compare active robotic-assisted TKA with the conventional technique. Data extraction and quality assessment were conducted for each study. Statistical analysis was performed using Revman V. 5.3.

Results

Seven studies with a total of 517 knees undergoing TKA were included. Compared with conventional surgery, active robotic TKA showed better outcomes in precise mechanical alignment (mean difference, MD: − 0.82, 95% CI: −1.15 to − 0.49, p < 0.05) and implant position, with lower outliers (p < 0.05), better functional score (Western Ontario and McMaster University, Knee Society Score functional score) and less drainage (MD: − 293.28, 95% CI: − 417.77 to − 168.79, p < 0.05). No significant differences were observed when comparing the operation time, range of motion and complication rates.

Conclusion

The current research demonstrates that active robotic-assisted TKA surgeries are more capable of improving mechanical alignment and prosthesis implantation when compared with conventional surgery. Further studies are required to investigate the potential benefits and long-term clinical outcomes of active robotic-assisted TKA.

Single-Stage Revision Surgery in Infected Total Knee Arthroplasty: A PRISMA Systematic Review

Periprosthetic joint infection in total knee arthroplasty is a significant complication that is a common reason for revision surgery. The current standard of care is two-stage revision surgery. There is however increasing evidence to support the use of single-stage revision surgery. We conducted a PRISMA systematic review of the current evidence on the use of single-stage revision for infected total knee arthroplasty. Four databases (PubMed, Embase, Science Direct, and Cochrane Library) were systematically screened for eligible studies. The risk bias of each study was identified using ROBINS-I tool, and the quality of evidence was assessed using the GRADE criteria. Sixteen articles were retained after applying the inclusion and exclusion criteria that evaluated 3645 knee single-stage revision surgeries. Our review reveals satisfactory outcomes for single-stage revision in the management of infected total knee arthroplasty. The reinfection rates in the studies included in our review varied however the majority reported low reinfection rates and good functional outcomes. Although strict patient selection criteria have yielded successful results, good results were also reported when these criteria were not applied. The greater use of risk factors in identifying patients likely to have a successful outcome needs to be balanced with the practical benefits of performing a single stage procedure in higher risk patients. Future large clinical randomized control trials are required to confirm our results.

Complications and Obesity in Arthroplasty-A Hip is Not a Knee

BACKGROUND

Obesity has previously been demonstrated to be an independent risk factor for increased complications after total hip and knee arthroplasties (THA and TKA). The purpose of this study was to compare the effects of obesity and body mass index (BMI) to determine whether the magnitude of the effect was similar for both procedures.

METHODS

We queried the American College of Surgeons National Surgical Quality Improvement Program database to identify patients who underwent primary THA or TKA between 2010 and 2014. Patients were stratified by procedure and classified as nonobese, obese, or morbidly obese according to BMI. Thirty-day rates of wound complications, deep infection, total complications, and reoperation were compared using univariate and multivariate logistic regression analyses.

RESULTS

We identified 64,648 patients who underwent THA and 97,137 patients who underwent TKA. Obese THA patients had significantly higher rates of wound complications (1.53% vs 0.96%), deep infection (0.31% vs 0.17%), reoperation rate (2.11% vs 1.02%), and total complications (5.22% vs 4.63%) compared with TKA patients. Morbidly obese patients undergoing THA were also found to have significantly higher rates of wound complications (3.25% vs 1.52%), deep infection (0.84% vs 0.23%), reoperation rate (3.65% vs 1.60%), and total complications (7.36% vs 5.57%). Multivariate regression analysis identified increasingly higher odds of each outcome measure as BMI increased.

CONCLUSION

This study demonstrates that the impact of obesity on postoperative complications is more profound for THA than TKA. This emphasizes the importance of considering patient comorbidities in the context of the specific procedure when assessing risks of surgery.

How Fast Should a Total Knee Arthroplasty Be Performed? An Analysis of 140,199 Surgeries

BACKGROUND

Although previous studies have shown that prolonged operative times can lead to an increased risk of complications after total knee arthroplasty (TKA), they only evaluated a few complications. It is also unclear whether a distinctive operative time exists after which complications increase. Therefore, this study was performed to (1) assess whether higher operative time increases the risk of complications within 30 days of TKA and (2) explore the relationship between operative time and various complications to identify possible operative times where complication rates increase.

METHODS

The National Surgical Quality Improvement Project database was queried from 2011 to 2015 to identify 140,199 primary TKAs. The effect of operative time (skin-to-skin) on various medical and surgical complications within 30 days was evaluated using multivariable logistic regression models. Spline regression models were created to further study the relationship between operative time and complications.

RESULTS

After adjusting for confounding factors, longer operative times were associated with higher risks of readmission (P < .001), reoperation (P < .001), surgical site infection (P < .001), wound dehiscence (P < .001), and transfusion (P < .001). The majority of the complications demonstrated an increase throughout the range of operative time, with a slightly pronounced increase in the risk of complications when the operative time was longer than 80 minutes.

CONCLUSION

Prolonged operative times were associated with an increased risk of a number of important complications such as readmissions, reoperations, surgical site infections, and wound complications. Based on our results, an operative time goal of less than 80 minutes is helpful for minimizing these complications after TKA.

Impact of Operative Time on Adverse Events Following Primary Total Joint Arthroplasty

BACKGROUND

Little is known regarding the impact of operative time on adverse events following arthroplasty. The present study tests for associations between a 15-minute increase in operative time and the occurrence of adverse events following primary total joint arthroplasty.

METHODS

Patients undergoing primary total hip or knee arthroplasty during 2006-2013 were identified in the American College of Surgeons National Surgical Quality Improvement Program. Operative time (as a continuous variable) was tested for association with perioperative outcomes using multivariate regression. All regressions were adjusted for differences in demographic, comorbidity, and procedural characteristics.

RESULTS

A total of 165,474 patients met inclusion criteria. The mean (±standard deviation) operative time was 91.9 ± 32.5 minutes. Following adjustment for baseline characteristics, an increase in operative time by 15 minutes increased the risk of anemia requiring transfusion by 9% (95% confidence interval [CI] = 8%-10%, P < .001), wound dehiscence by 13% (95% CI = 8%-19%, P < .001), renal insufficiency by 9% (95% CI = 3%-14%, P < .001), sepsis by 10% (95% CI = 6%-14%, P < .001), surgical site infection by 9% (95% CI = 7%-12%, P < .001), and urinary tract infection by 4% (95% CI = 2%-6%, P < .001). Similarly, an increase in operative time by 15 minutes increased the risk of hospital readmission by 5% (95% CI = 4%-6%, P < .001) and of extended hospital length of stay (≥4 days) by 9% (95% CI = 8%-10%, P < .001).

CONCLUSION

The present study suggests that greater operative time increases the risk for multiple postoperative complications following total joint arthroplasty. These data suggest that surgeons should consider steps to minimize operative time without compromising the technical components of the surgical procedure.