Age-Based Heuristics Bias Treatment of Displaced Femoral Neck Fractures in the Elderly

Background

Surgeons performing arthroplasty for femoral neck fractures may rely on mental shortcuts (heuristics) when choosing total hip arthroplasty (THA) vs hemiarthroplasty (HA). We sought to quantify the extent to which age-based heuristics drive decision-making.

Methods

We identified all Medicare beneficiaries from 2017-2018 with femoral neck fractures who underwent THA or HA. We compared the likelihood of THA vs HA among patients admitted within 4 weeks before vs 4 weeks after their birthday for each age under the hypothesis that these cohorts would be similar except for numerical age. We controlled for race/ethnicity, sex, comorbidities, poverty status, and hospital census region in a multivariable regression that included facility-level cluster effects. We generated predicted/adjusted probabilities for THA vs HA for different age transition points.

Results

Thirteen thousand three hundred sixty-six elderly patients were included. One thousand eight hundred sixty-five (14%) received THA and 11,501 (86%) received HA. The likelihood of THA decreased from 50.3% among patients almost 67 to 8% among those ≥85 (P < .001). We found significant decreases in likelihood of THA across age transitions. The largest decrement was at age transition 69 (THA likelihood 28.7% for newly 69 vs 43.3% for almost 69, 33.7% relative change). Female gender, Black race, higher comorbidity burden, and lower socioeconomic status were also associated with a lower likelihood of THA.

Conclusions

Our data demonstrate that patient age transitions seem to influence the choice of THA vs HA. Further research is needed to develop data-driven surgical decision aids for this population.

Peptidoglycan in osteoarthritis synovial tissue is associated with joint inflammation

OBJECTIVES

Peptidoglycan (PG) is an arthritogenic bacterial cell wall component whose role in human osteoarthritis is poorly understood. The purpose of this study was to determine if PG is present in synovial tissue of osteoarthritis patients at the time of primary total knee arthroplasty (TKA), and if its presence is associated with inflammation and patient reported outcomes.

METHODS

Intraoperative synovial tissue and synovial fluid samples were obtained from 56 patients undergoing primary TKA, none of whom had history of infection. PG in synovial tissue was detected by immunohistochemistry (IHC) and immunofluorescence microscopy (IFM). Synovial tissue inflammation and fibrosis were assessed by histopathology and synovial fluid cytokine quantification. Primary human fibroblasts isolated from arthritis synovial tissue were stimulated with PG to determine inflammatory cytokine response.

RESULTS

A total of 33/56 (59%) of primary TKA synovial tissue samples were positive for PG by IHC, and PG staining colocalized with markers of synovial macrophages and fibroblasts by IFM. Synovial tissue inflammation and elevated IL-6 in synovial fluid positively correlated with PG positivity. Primary human fibroblasts stimulated with PG secreted high levels of IL-6, consistent with ex vivo findings. Interestingly, we observed a significant inverse correlation between PG and age at time of TKA, indicating younger age at time of TKA was associated with higher PG levels.

CONCLUSION

Peptidoglycan is commonly found in synovial tissue from patients undergoing TKA. Our data indicate that PG may play an important role in inflammatory synovitis, particularly in patients who undergo TKA at a relatively younger age.

Racial and Ethnic Minorities Underrepresented in Pain Management Guidelines for Total Joint Arthroplasty: A Meta-analysis

BACKGROUND

Total joint arthroplasty aims to improve quality of life and functional outcomes for all patients, primarily by reducing their pain. This goal requires clinical practice guidelines (CPGs) that equitably represent and enroll patients from all racial/ethnic groups. To our knowledge, there has been no formal evaluation of the racial/ethnic composition of the patient population in the studies that informed the leading CPGs on the topic of pain management after arthroplasty surgery.

QUESTIONS/PURPOSES

Using papers included in the 2021 Anesthesia and Analgesia in Total Joint Arthroplasty Clinical Practice Guidelines and comparing them with US National census data, we asked: (1) What is the representation of racial/ethnic groups in randomized controlled trials compared with their representation in the US national population? (2) Is there a relationship between the reporting of racial/ethnic groups and year of data collection/publication, location of study, funding source, or guideline section?

METHODS

Participant demographic data (study year published, study type, guideline section, year of data collection, study site, study funding, study size, gender, age, and race/ethnicity) were collected from articles cited by this guideline. Studies were included if they were full text, were primary research articles conducted primarily within the United States, and if they reported racial and ethnic characteristics of the participants. The exclusion criteria included duplicate articles, articles that included the same participant population (only the latest dated article was included), and the following article types: systematic reviews, nonsystematic reviews, terminology reports, professional guidelines, expert opinions, population-based studies, surgical trials, retrospective cohort observational studies, prospective cohort observational studies, cost-effectiveness studies, and meta-analyses. Eighty-two percent (223 of 271) of articles met inclusion criteria. Our original literature search yielded 27 papers reporting the race/ethnicity of participants, including 24 US-based studies and three studies conducted in other countries; only US-based studies were utilized as the focus of this study. We defined race/ethnicity reporting as the listing of participants' race or ethnicity in the body, tables, figures, or supplemental data of a study. National census information from 2000 to 2019 was then used to generate a representation quotient (RQ), which compared the representation of racial/ethnic groups within study populations to their respective demographic representation in the national population. An RQ value greater than 1 indicates an overrepresented group and an RQ value less than 1 indicates an underrepresented group, relative to the US population. Primary outcome measures of RQ value versus time of publication for each racial/ethnic group were evaluated with linear regression analysis, and race reporting and manuscript parameters were analyzed with chi-square analyses.

RESULTS

Two US-based studies reported race and ethnicity independently. Among the 24 US-based studies reporting race/ethnicity, the overall RQ was 0.70 for Black participants, 0.09 for Hispanic participants, 0.1 for American Indian/Alaska Natives, 0 for Native Hawaiian/Pacific Islanders, 0.08 for Asian participants, and 1.37 for White participants, meaning White participants were overrepresented by 37%, Black participants were underrepresented by 30%, Hispanic participants were underrepresented by 91%, Asian participants were underrepresented by 92%, American Indian/Alaska Natives were 90% underrepresented, and Native Hawaiian Pacific Islanders were virtually not represented compared with the US national population. On chi-square analysis, there were differences between race/ethnicity reporting among studies with academic, industry, and dual-supported funding sources (χ2 = 7.449; p = 0.02). Differences were also found between race/ethnicity reporting among US-based and non-US-based studies (χ2 = 36.506; p < 0.001), with 93% (25 of 27) of US-based studies reporting race as opposed to only 7% (2 of 27) of non-US-based studies. Finally, there was no relationship between race/ethnicity reporting and the year of data collection or guideline section referenced.

CONCLUSION

The 2021 Anesthesia and Analgesia in Total Joint Arthroplasty Clinical Practice Guidelines provide evidence-based recommendations that reflect the current standards in orthopaedic surgery, but the studies upon which they are based overwhelmingly underenroll and underreport racial/ethnic minorities relative to their proportions in the US population. As these factors impact analgesic administration, their continued neglect may perpetuate inequities in outcomes after TJA.

CLINICAL RELEVANCE

Our study demonstrates that all non-White racial/ethnic groups were underrepresented relative to their proportion of the US population in the 2021 Anesthesia and Analgesia in Total Joint Arthroplasty Clinical Practice Guidelines, underscoring a weakness in the orthopaedic surgery evidence base and questioning the overall external validity and generalizability of these combined CPGs. An effort should be made to equitably enroll and report outcomes for all racial/ethnic groups in any updated CPGs.

Imageless robotic total knee arthroplasty determines similar coronal plane alignment of the knee (CPAK) parameters to long leg radiographs

BACKGROUND

The coronal plane alignment of the knee (CPAK) classification was first developed using long leg radiographs (LLR) and has since been reported using image-based and imageless robotic total knee arthroplasty (TKA) systems. However, the correspondence between imageless robotics and LLR-derived CPAK parameters has yet to be investigated. This study therefore examined the differences in CPAK parameters determined with LLR and imageless robotic navigation using either generic or optimized cartilage wear assumptions.

METHODS

Medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA) were determined from the intraoperative registration data of 61 imageless robotic TKAs using either a generic 2 mm literature-based wear assumption (Navlit) or an optimized wear assumption (Navopt) found using an error minimization algorithm. MPTA and LDFA were also measured from preoperative LLR by two observers and intraclass correlation coefficients (ICCs) were calculated. MPTA, LDFA, joint line obliquity (JLO), and arithmetic hip-knee-ankle angle (aHKA) were compared between the robotic and the average LLR measurements over the two observers.

RESULTS

ICCs between observers for LLR were over 0.95 for MPTA, LDFA, JLO, and aHKA, indicating excellent agreement. Mean CPAK differences were not significant between LLR and Navlit (all differences within 0.6°, P > 0.1) or Navopt (all within 0.1°, P > 0.83). Mean absolute errors (MAE) between LLR and Navlit were: LDFA = 1.4°, MPTA = 2.0°, JLO = 2.1°, and aHKA = 2.7°. Compared to LLR, the generic wear classified 88% and the optimized wear classified 94% of knees within one CPAK group. Bland-Altman comparisons reported good agreement for LLR vs. Navlit and Navopt, with > 95% and > 91.8% of measurements within the limits of agreement across all CPAK parameters, respectively.

CONCLUSIONS

Imageless robotic navigation data can be used to calculate CPAK parameters for arthritic knees undergoing TKA with good agreement to LLR. Generic wear assumptions determined MPTA and LDFA with MAE within 2° and optimizing wear assumptions showed negligible improvement.

The Role of the Gut Microbiome in Orthopedic Surgery-a Narrative Review

PURPOSE OF REVIEW

The importance of the gut microbiome has received increasing attention in recent years. New literature has revealed significant associations between gut health and various orthopedic disorders, as well as the potential for interventions targeting the gut microbiome to prevent disease and improve musculoskeletal outcomes. We provide a broad overview of available literature discussing the links between the gut microbiome and pathogenesis and management of orthopedic disorders.

RECENT FINDINGS

Human and animal models have characterized the associations between gut microbiome dysregulation and diseases of the joints, spine, nerves, and muscle, as well as the physiology of bone formation and fracture healing. Interventions such as probiotic supplementation and fecal transplant have shown some promise in ameliorating the symptoms or slowing the progression of these disorders. We aim to aid discussions regarding optimization of patient outcomes in the field of orthopedic surgery by providing a narrative review of the available evidence-based literature involving gut microbiome dysregulation and its effects on orthopedic disease. In general, we believe that the gut microbiome is a viable target for interventions that can augment current management models and lead to significantly improved outcomes for patients under the care of orthopedic surgeons.

Hemiarthroplasty Versus Total Hip Arthroplasty for Femoral Neck Fracture in Elderly Patients: Twelve-Month Risk of Revision and Dislocation in an Instrumental Variable Analysis of Medicare Data

BACKGROUND

There is practice variation in the selection of a total hip arthroplasty (THA) or a hemiarthroplasty (HA) for the treatment of displaced femoral neck fractures in elderly patients. Large data sets are needed to compare the rates of rare complications following these procedures. We sought to examine the relationship between surgery type and secondary hip surgery (revision or conversion arthroplasty) at 12 months following the index arthroplasty, and that between surgery type and dislocation at 12 months, among elderly Medicare beneficiaries who underwent THA or HA for a femoral neck fracture, taking into account the potential for selection bias.

METHODS

We performed a population-based, retrospective study of elderly (>65 years of age) Medicare beneficiaries who underwent THA or HA following a femoral neck fracture. Two-stage, instrumental variable regression models were applied to nationally representative Medicare medical claims data from 2017 to 2019.

RESULTS

Of the 61,695 elderly patients who met the inclusion criteria, of whom 74.1% were female and 92.2% were non-Hispanic White, 10,268 patients (16.6%) underwent THA and 51,427 (83.4%) underwent HA. The findings from the multivariable, instrumental variable analyses indicated that treatment of displaced femoral neck fractures with THA was associated with a significantly higher risk of dislocation at 12 months compared with treatment with HA (2.9% for the THA group versus 1.9% for the HA group; p = 0.001). There was no significant difference in the likelihood of 12-month revision/conversion between THA and HA.

CONCLUSIONS

The use of THA to treat femoral neck fractures in elderly patients is associated with a significantly higher risk of 12-month dislocation, as compared with the use of HA, although the difference may not be clinically important. A low overall rate of dislocation was found in both groups. The risk of revision/conversion at 12 months did not differ between the groups.

LEVEL OF EVIDENCE

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

Laxity, Balance, and Alignment of a Simulated Kinematic Alignment Total Knee Arthroplasty

Background

Kinematic alignment (KA) and related personalized alignment strategies in total knee arthroplasty (TKA) target restoration of native joint line obliquity and alignment. In practice, deviations from exact restoration of the prearthritic joint surface are tolerated for either the femur or tibia to achieve ligamentous balance. It remains unknown what laxity, balance, and alignment would result if a pure resurfacing of both femur and tibia were performed in a KA TKA technique.

Methods

We used data from 382 robot-assisted TKA performed with a digital joint tensioner to simulate TKA with a pure resurfacing KA technique for both femur and tibia. All knees had the posterior cruciate ligament retained. Knees were subdivided into 4 groups based on preoperative coronal alignment: valgus, neutral, varus, and high varus. Medial and lateral laxity in extension and flexion, balance in extension and flexion, and coronal plane alignment were compared between groups using analysis of variance testing.

Results

In simulated pure resurfacing KA TKA across a range of preoperative coronal plane deformities, only 11%-31% of knees would have mediolateral extension ligament balance within ±1 mm, and 20%-41% would have a medial flexion gap that is looser than the lateral flexion gap. Over 45% of knees would have coronal hip-knee-ankle angle >3 degrees from mechanical neutral.

Conclusions

In simulations of pure resurfacing KA TKA, there was wide variability in the resulting laxity and alignment outcomes. Most knees had alignment and balance outcomes outside of normally accepted ranges. Techniques that deviate from pure resurfacing in order to achieve balance appear favorable.

Peptidoglycan in osteoarthritis synovial tissue is associated with joint inflammation

Objectives

Peptidoglycan (PG) is an arthritogenic bacterial cell wall component whose role in human osteoarthritis is poorly understood. The purpose of this study was to determine if PG is present in synovial tissue of osteoarthritis patients at the time of primary total knee arthroplasty (TKA), and if its presence is associated with inflammation and patient reported outcomes.

Methods

Intraoperative synovial tissue and synovial fluid samples were obtained from 56 patients undergoing primary TKA, none of whom had history of infection. PG in synovial tissue was detected by immunohistochemistry (IHC). Synovial tissue inflammation and fibrosis were assessed by histopathology and synovial fluid cytokine quantification. Primary human fibroblasts isolated from arthritis synovial tissue were stimulated with PG to determine inflammatory cytokine response.

Results

A total of 33/56 (59%) of primary TKA synovial tissue samples were positive for PG by IHC, with mean 8 PG occurrences per 10 mm2 of tissue in PG-positive samples. Synovial tissue inflammation and elevated IL-6 in synovial fluid positively correlated with PG positivity. Primary human fibroblasts stimulated with PG secreted high levels of IL-6, consistent with ex vivo findings. Interestingly, we observed a significant inverse correlation between PG and age at time of TKA, indicating younger age at time of TKA was associated with higher PG levels.

Conclusion

Peptidoglycan is commonly found in synovial tissue from patients undergoing TKA. Our data indicate that PG may play an important role in inflammatory synovitis, particularly in patients who undergo TKA at a relatively younger age.

PSAT159 Does Untreated Hypercalcemia Affect Postoperative Joint Pain Following Hip and Knee Arthroplasty for Osteoarthritis? A Retrospective Case Cohort Study

Background/Objective

Primary hyperparathyroidism (pHPT) is characterized by the excess secretion of parathyroid hormone (PTH), leading to hypercalcemia. pHPT is a known cause of joint pain, which is the key element in the decision regarding possible arthroplasty in patients with osteoarthritis (OA). The effect of hypercalcemia on arthroplasty outcomes has not been studied. This study investigates the association between preoperative hypercalcemia and postoperative outcomes following total knee (TKA) and total hip arthroplasty (THA).

Methods

A retrospective chart review was conducted on patients who underwent initial elective THA and/or TKA at an academic medical center between 2015-2019. Patient characteristics and outcomes were obtained. Hypercalcemia was used as a proxy for pHPT as PTH is not routinely obtained in the orthopedic setting. Patients with a preoperative serum calcium &gt;10.2 mg/dL were matched (1: 2-1: 4) with nearest neighbor matching to patients with normal serum calcium based on age, sex, BMI, Charlson Comorbidity Index, American Society of Anesthesiologists class, type of surgery (hip or knee), and date of surgery. THA and TKA functional outcomes were measured at baseline and one-year postoperatively using patient-reported Hip Disability and Osteoarthritis Outcome Scores (HOOS JR) and Knee Injury and Osteoarthritis Outcome Scores (KOOS JR) surveys, respectively. A score of '0' represents total joint disability; '100' represents perfect joint health. Patients with incomplete HOOS JR or KOOS JR scores were excluded. Postoperative complications, readmissions, length of stay, and functional outcome scores were compared.

Results

Of 5215 patients identified, 269 (5%) were hypercalcemic. The final cohort included 495 patients (106 [21%] hypercalcemic cases, 389 matched controls). Of these, 223 patients underwent THA (46 [21%] cases; 177 controls) and 272 patients underwent TKA (61 [22%] cases; 211 controls). There were no differences in HOOS JR and KOOS JR scores between cases and controls at baseline (HOOS JR: 49.6±12.9 vs 52.8±13.3; KOOS JR: 52.5±12.1 vs 53.5±11.4) or at one-year postoperatively (HOOS JR: 83.6±16.2 vs 84.7±15.5; KOOS JR: 78.0±13.1 vs 75.5±15.3). There also were no differences in rates of postoperative complications, readmissions, or length of stay. Only 19/106 (18%) hypercalcemic patients had a PTH drawn, and of these, 9 (47%) had possible pHPT (PTH&gt;40). Sub-analysis of these 9 patients demonstrated similar HOOS JR and KOOS JR scores to controls at both timepoints.

Conclusion

Patients with hypercalcemia undergoing arthroplasty have similar functional and postoperative outcomes as normocalcemic patients. Analysis of patients with possible pHPT was limited, as a PTH was obtained in &lt;20% of patients with hypercalcemia. However, nearly 50% of these patients had possible pHPT. Therefore, we recommend that all patients being evaluated for arthroplasty have a calcium level checked, and if high, be evaluated for possible pHPT. Additional investigation is needed to determine the effect of pHPT on arthroplasty outcomes.

Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

Knee Arthrofibrosis following Tibial Plateau Fracture Treated with Arthroscopic Lysis of Adhesions with Manipulation

Posttraumatic arthrofibrosis is a common problem encountered in the orthopaedic setting for which there is no agreement on the optimal management strategy. The literature does not optimally describe the efficacy of arthroscopic lysis of adhesions for arthrofibrosis following tibial plateau fracture. The purpose of this study is to quantify the efficacy of arthroscopic lysis of adhesions with manipulation for the treatment of arthrofibrosis of the knee in patients who previously underwent surgical management of tibial plateau fracture. All patients who underwent arthroscopic lysis of adhesions from a single surgeon since 1999 were retrospectively reviewed. Clinical outcomes were evaluated by flexion, extension, and range of motion (ROM) preoperatively, intraoperatively, and postoperatively at intervals of 1, 4, 8, and 12 weeks, and any additional long-term follow-up. A total of 28 patients who had developed arthrofibrosis following surgical management of a tibial plateau fracture and failed nonsurgical management of knee stiffness were included in this study. There were significant improvements in total ROM following intervention at all time points compared with preoperative values (p < 0.001), with mean improvements of 59.3 degrees intraoperatively, 32.9 degrees (1 week), 37.1 degrees (4 weeks), 41.5 degrees (8 weeks), and 47.6 degrees (12 weeks). There were significant improvements in degrees of knee flexion following intervention at all time points compared with preoperative values (p < 0.001), with mean improvements of 50.8 degrees intraoperatively, 27.3 degrees (1 week), 36.0 degrees (4 weeks), 38.3 degrees (8 weeks), and 43.9 degrees (12 weeks). There were significant increases in degrees of knee extension intraoperatively (8.5 degrees) and at 1 week postoperatively (5.9 degrees) compared with preoperative values (p <0.01). At 12 weeks postoperatively, those who had previously undergone external fixation had significantly greater increases in ROM (p = 0.048). Arthroscopic lysis of adhesions for knee arthrofibrosis following surgical management of tibial plateau fracture significantly improves knee ROM.

The Impact of Femoral Component Cementation on Fracture and Mortality Risk in Elective Total Hip Arthroplasty: Analysis from a National Medicare Sample

BACKGROUND

Complications following elective total hip arthroplasty (THA) are rare but potentially devastating. The impact of femoral component cementation on the risk of periprosthetic femoral fractures and early perioperative death has not been studied in a nationally representative population in the United States.

METHODS

Elective primary THAs performed with or without cement among elderly patients were identified from Medicare claims from 2017 to 2018. We performed separate nested case-control analyses matched 1:2 on age, sex, race/ethnicity, comorbidities, payment model, census division of facility, and exposure time and compared fixation mode between (1) groups with and without 90-day periprosthetic femoral fracture and (2) groups with and without 30-day mortality.

RESULTS

A total of 118,675 THAs were included. The 90-day periprosthetic femoral fracture rate was 2.0%, and the 30-day mortality rate was 0.18%. Cases were successfully matched. The risk of periprosthetic femoral fracture was significantly lower among female patients with cement fixation compared with matched controls with cementless fixation (OR = 0.83; 95% CI, 0.69 to 1.00; p = 0.05); this finding was not evident among male patients (p = 0.94). In contrast, the 30-day mortality risk was higher among male patients with cement fixation compared with matched controls with cementless fixation (OR = 2.09; 95% CI, 1.12 to 3.87; p = 0.02). The association between cement usage and mortality among female patients almost reached significance (OR = 1.74; 95% CI, 0.98 to 3.11; p = 0.06).

CONCLUSIONS

In elderly patients managed with THA, cemented stems were associated with lower rates of periprosthetic femoral fracture among female patients but not male patients. The association between cemented stems and higher rates of 30-day mortality was significant for male patients and almost reached significance for female patients, although the absolute rates of mortality were very low. For surgeons who can competently perform THA with cement, our data support the use of a cemented stem to avoid periprosthetic femoral fracture in elderly female patients.

LEVEL OF EVIDENCE

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

Association Between Nonsurgical Weight Loss From Body Mass Index >40 to Body Mass Index <40 and Complications and Readmissions Following Total Hip Arthroplasty

BACKGROUND

Elevated body mass index (BMI) is a risk factor for adverse outcomes following total hip arthroplasty (THA). It is unknown if preoperative weight loss to a BMI <40 kg/m² is associated with reduced risk of adverse outcomes.

METHODS

We retrospectively reviewed elective, primary THA performed at an academic center from 2015 to 2019. Patients were split into groups based on their BMI trajectory prior to THA: BMI consistently <40 ("BMI <40"); BMI >40 at the time of surgery ("BMI >40"); and BMI >40 within 2 years preoperatively, but <40 at the time of surgery ("Weight Loss"). Length of stay (LOS), 30-day readmissions, and complications as defined by Centers for Medicare and Medicaid Services were compared between groups using parsimonious regression models and Fisher's exact testing. Adjusted analyses controlled for sex, age, and American Society of Anesthesiologists class.

RESULTS

In total, 1589 patients were included (BMI <40: 1387, BMI >40: 96, Weight Loss: 106). The rate of complications in each group was 3.5%, 6.3%, and 8.5% and the rate of 30-day readmissions was 3.0%, 4.2%, and 7.5%, respectively. Compared to the BMI <40 group, the weight loss group had a significantly higher risk of 30-day readmission (odds ratio [OR] 2.70, 95% confidence interval [CI] 1.19-6.17, P = .02), higher risk of any complication (OR 2.47, 95% CI 1.09-5.59, P = .03), higher risk of mechanical complications (OR 3.07, 95% CI 1.14-8.25, P = .03), and longer median LOS (16% increase, P = .002). The BMI >40 group had increased median LOS (10% increase, P = .03), but no difference in readmission or complications (P > .05) compared to BMI <40.

CONCLUSION

Weight loss from BMI >40 to BMI <40 prior to THA was associated with increased risk of readmission and complications compared to BMI <40, whereas BMI >40 was not.

LEVEL OF EVIDENCE

Level III - Retrospective Cohort Study.

The Impact of Pre-Operative Healthcare Utilization on Complications, Readmissions, and Post-Operative Healthcare Utilization Following Total Joint Arthroplasty

BACKGROUND

Identifying risk factors for adverse outcomes and increased costs following total joint arthroplasty (TJA) is needed to ensure quality. The interaction between pre-operative healthcare utilization (pre-HU) and outcomes following TJA has not been fully characterized.

METHODS

This is a retrospective cohort study of patients undergoing elective, primary total hip arthroplasty (THA, N = 1785) or total knee arthroplasty (TKA, N = 2159) between 2015 and 2019 at a single institution. Pre-HU and post-operative healthcare utilization (post-HU) included non-elective healthcare utilization in the 90 days prior to and following TJA, respectively (emergency department, urgent care, observation admission, inpatient admission). Multivariate regression models including age, gender, American Society of Anesthesiologists, Medicaid status, and body mass index were fit for 30-day readmission, Centers for Medicare and Medicaid services (CMS)-defined complications, length of stay, and post-HU.

RESULTS

The 30-day readmission rate was 3.2% and 3.4% and the CMS-defined complication rate was 3.8% and 2.9% for THA and TKA, respectively. Multivariate regression showed that for THA, presence of any pre-HU was associated with increased risk of 30-day readmission (odds ratio [OR] 2.85, 95% confidence interval [CI] 1.48-5.50, P = .002), CMS complications (OR 2.42, 95% CI 1.27-4.59, P = .007), and post-HU (OR 3.65, 95% CI 2.54-5.26, P < .001). For TKA, ≥2 pre-HU events were associated with increased risk of 30-day readmission (OR 3.52, 95% CI 1.17-10.61, P = .026) and post-HU (OR 2.64, 95% CI 1.29-5.40, P = .008). There were positive correlations for THA (any pre-HU) and TKA (≥2 pre-HU) with length of stay and number of post-HU events.

CONCLUSION

Patients who utilize non-elective healthcare in the 90 days prior to TJA are at increased risk of readmission, complications, and unplanned post-HU.

LEVEL OF EVIDENCE

Level III.

What Mid-term Patient-reported Outcome Measure Scores, Reoperations, and Complications Are Associated with Concurrent Hip Arthroscopy and Periacetabular Osteotomy to Treat Dysplasia with Associated Intraarticular Abnormalities?

BACKGROUND

Periacetabular osteotomy (PAO) is a well-accepted treatment for acetabular dysplasia, but treatment success is not uniform. Concurrent hip arthroscopy has been proposed for select patients to address intraarticular abnormalities. The patient-reported outcomes, complications, and reoperations for concurrent arthroscopy and PAO to treat acetabular dysplasia remain unclear.

QUESTIONS/PURPOSES

(1) What are the functional outcome scores among select patients treated with PAO plus concurrent hip arthroscopy at mid-term follow-up? (2) What factors are associated with conversion to THA or persistent symptoms (modified Harris hip score ≤ 70 or WOMAC pain subscore ≥ 10)? (3) What proportion of patients underwent further hip preservation surgery at mid-term follow-up? (4) What are the complications associated with the procedure?

METHODS

Between November 2005 and December 2012, 78 patients (81 hips) who presented with symptomatic acetabular dysplasia-defined as a lateral center-edge angle less than 20° with hip pain for more than 3 months that interfered with daily function-had undergone unsuccessful nonsurgical treatment, had associated intraarticular abnormalities on MRI, and underwent combined hip arthroscopy and PAO. Eleven patients did not have minimum 4-year follow-up and were excluded, leaving 67 patients (70 hips) who met our inclusion criteria and had a mean follow-up duration of 6.5 ± 1.6 years. We retrospectively evaluated patient-reported outcomes at final follow-up using the University of California Los Angeles (UCLA) activity score, the modified Harris Hip Score (mHHS), and the WOMAC pain subscore. Conversion to THA or persistent symptoms were considered clinical endpoints. Repeat surgical procedures were drawn from a prospectively maintained database, and major complications were graded according to the validated Clavien-Dindo classification (Grade III or IV). Student t-tests, chi-square tests, and Fisher exact tests identified the association of patient factors, radiographic measures, and surgical details with clinical endpoints. For patients who underwent bilateral procedures, only the first hip was included in our analyses.

RESULTS

At final follow-up, the mean mHHS for all patients improved from a mean ± SD of 55 ± 19 points to 85 ± 17 points (p < 0.001), the UCLA activity score improved from 6.5 ± 2.7 points to 7.5 ± 2.2 points (p = 0.01), and the WOMAC pain score improved from 9.1 ± 4.3 points to 3.2 ± 3.9 points (p < 0.001). Three percent (2 of 67) of patients underwent subsequent THA, while 21% (15 of 70) of hips were persistently symptomatic, defined as mHHS less than or equal to 70 or WOMAC pain subscore greater than or equal to 10. Univariate analyses indicated that no patient demographics, preoperative or postoperative radiographic metrics, or intraoperative findings or procedures were associated with subsequent THA or symptomatic hips. Worse baseline mHHS and WOMAC pain scores were associated with subsequent THA or symptomatic hips. Seven percent (5 of 67) of patients underwent repeat hip preservation surgery for recurrent symptoms, and 4% (3 of 67) of patients had major complications (Clavien-Dindo Grade III or IV).

CONCLUSION

This study demonstrated that concurrent hip arthroscopy and PAO to treat symptomatic acetabular dysplasia (with intraarticular abnormalities) has good clinical outcomes at mid-term follow-up in many patients; however, persistent symptoms or conversion to THA affected almost a quarter of the sample. We noted an acceptable complication profile. Further study is needed to directly compare this approach to more traditional techniques that do not involve arthroscopy. We do not use isolated hip arthroscopy to treat symptomatic acetabular dysplasia.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Assessment of Psychological Factors in Short-Stay Total Hip Arthroplasty Protocol

BACKGROUND

Several variables are known to correlate with the successful completion of short-stay total hip arthroplasty (THA) protocols. The role of psychological factors remains unclear. We investigated the interaction between patient-reported measures of psychological fitness and successful completion of a short-stay THA protocol.

METHODS

We performed a prospective cohort study of patients undergoing elective anterior total hip arthroplasty enrolled in a short-stay protocol (success defined as LOS ≤1 midnight versus failed, LOS >1 midnight). Psychological fitness was measured using the Patient-Reported Outcomes Measurement Information System (PROMIS) domains for self-efficacy, depression, anxiety, emotional support, and the ability to participate in social roles. PROMIS scores, patient demographics, and surgical factors were assessed for a relationship with failure to complete short-stay protocol.

RESULTS

Patients that failed to complete the short-stay protocol had higher mean pre-operative PROMIS depression scores (50.8 vs 47.1, P = .025) and anxiety scores (53.6 vs 49.2, P = .008) and higher postoperative PROMIS depression (48.19 vs 43.49, P = .003) and anxiety scores (51.7 vs 47.1, P = .01). Demographic and surgical variables did not correlate with the successful completion of the short-stay protocol. That seventy-six percent of the patients did not adhere to the short-stay protocol was due to the inability to complete a physical therapy standardized safety assessment.

CONCLUSION

Higher levels of preoperative and postoperative anxiety and depression in otherwise psychologically healthy patients, is associated with an increased risk of failure to complete a short-stay protocol following THA. Targeted interventions are needed to facilitate rapid recovery in patients with psychological barriers to early mobilization.

In-Bundle Surgeons More Likely Select Cemented Femoral Fixation in Total Hip Arthroplasty for At-Risk Patients: The Medicare Comprehensive Care for Joint Replacement Bundled Model

Background

Bundled payment models for lower-extremity arthroplasty have been shown to lower costs but have not reliably improved quality. It is unknown how the bundled payment model may affect surgeons' decisions that impact the quality of arthroplasty care. The purpose of this study was to compare the utilization of femoral component fixation modes by surgeons performing total hip arthroplasties (THAs) in at-risk patients in areas subject to Medicare's Comprehensive Care for Joint Replacement (CJR) bundled payment model compared with patients treated by surgeons in areas exempt from the policy.

Methods

Elective, primary THAs among elderly persons were identified from Medicare claims during 2017 and 2018, including the use of cemented or cementless femoral fixation. Multivariable regression models, applied to samples stratified by sex, were used to assess the association between CJR bundle participation and the use of femoral fixation mode. Analyses were adjusted for patient age, race or ethnicity, comorbidity burden, low-income status, and Census division of the hospital.

Results

Of 118,676 Medicare patients who underwent THA, 9.1% received cemented femoral components, and use of cement varied significantly by geographic region (p < 0.001). Patients who received cemented fixation, compared with patients who received cementless fixation, had significant differences in mean age (and standard deviation) at 78.3 ± 6.9 years compared with 74.5 ± 6.1 years (p < 0.001) for female patients and 77.3 ± 6.8 years and 74.2 ± 5.9 years (p < 0.001) for male patients; were more likely to be White at 94.0% compared with 92.7% (p < 0.001) for female patients and 95.1% compared with 93.8% (p = 0.046) for male patients; and had higher mean Elixhauser comorbidity index at 2.6 ± 2.2 compared with 2.3 ± 2.0 (p < 0.001) for female patients and 2.8 ± 2.4 compared with 2.4 ± 2.1 (p < 0.001) for male patients. In adjusted analyses, female patients in the CJR bundled payment model were more likely to have cemented fixation compared with female patients not in the CJR model (odds ratio [OR], 1.11 [95% confidence interval (CI), 1.05 to 1.16]; p < 0.001), whereas male patients in the CJR bundled payment model were less likely to have cemented fixation compared with male patients not in the CJR model (OR, 0.91 [95% CI, 0.83 to 0.99]; p = 0.029).

Conclusions

In the bundled environment, surgeons were more likely to choose cemented femoral fixation for elderly female patients. This may be due to in-bundle surgeons being more risk-averse and avoiding cementless fixation in patients at risk for fracture or implant-related complications. Further research is needed to directly examine the impact of the bundle on surgeon decision-making.

Arthroscopic Lysis of Adhesions With Manipulation for Management of Late-Presenting Stiffness After Total Knee Arthroplasty

Background

Arthrofibrosis is a known complication of total knee arthroplasty (TKA). Closed manipulation is the treatment of choice for arthrofibrosis within 90 days of TKA. Treatment for arthrofibrosis that has failed prior interventions remains controversial, and the role for arthroscopic lysis of adhesions has not been examined for late-presenting arthrofibrosis.

Methods

A retrospective analysis of patients who underwent arthroscopic lysis of adhesions (LOAs) with manipulation for post-TKA arthrofibrosis was performed. Chart review included patient characteristics, time from TKA, prior interventions, and range of motion (ROM) data. Knee extension, flexion, and total ROM were recorded preoperatively, intraoperatively, and throughout follow-up. Knee ROM was compared at the different time intervals using Wilcoxon signed-rank tests.

Results

A total of 13 patients (6 male and 7 female) with a mean age of 66.3 years were included. Average time since index TKA was 57.2 months (3.7-209.5). Ten of 13 patients had undergone prior interventions for arthrofibrosis, which included closed manipulation under anesthesia, open LOA, and revision arthroplasty. The mean preoperative knee flexion and extension values for the cohort were 76.5 ± 17.4 and −4.6 ± 6.1 degrees, respectively. Postoperative improvements in knee ROM were significant at all time points, with mean improvements of 17.2 ± 16.3 degrees at 1 week (P = .022), 17.2 ± 13.2 degrees at 4 weeks (P = .001), 19.2 ± 16.0 degrees at 8 weeks (P = .004), and 25.2 ± 13.1 degrees at 12 weeks (P = .005). No complications were recorded.

Conclusions

Arthroscopic LOAs with manipulation achieves significant improvements in knee ROM for late-presenting arthrofibrosis after TKA.

The Effect of Implant Design on Sagittal Plane Stability: A Randomized Trial of Medial- versus Posterior-Stabilized Total Knee Arthroplasty

Up to 20% of total knee arthroplasty (TKA) patients report dissatisfaction with their outcome, especially with weight-bearing in flexion (WBiF) activities. Sagittal plane instability may contribute to dissatisfaction following TKA. We assessed the impact of implant design on TKA sagittal plane stability and clinical satisfaction. We randomized patients to receive one of two TKA implant designs: medial-stabilized (MS) or posterior-stabilized (PS). Sagittal stability was assessed using a KT-1000 arthrometer. Patient-reported outcome measures, including a custom bank of questions targeting patient satisfaction (0-100%) with WBiF activities, were administered to patients 2 years following surgery. The final analysis included 50 patients (25 MS, 25 PS). The MS group had greater sagittal plane stability than the PS group at 30-degree flexion (5.6 ± 1.9 vs. 10.2 ± 2.7 mm; p < 0.0001) but not at 90-degree flexion (4.1 ± 2 vs. 5.3 ± 3 mm; p = 0.14). Range of motion was not different (111.3 ± 10.4 vs. 114.7 ± 10.7 degrees; p = 0.31). There were no differences in the PROMIS (Patient-Reported Outcomes Measurement Information System) score, Oxford Knee Score, Knee Society Score, Forgotten Joint Score, or Veterans Rand. The MS group had no difference in satisfaction for WBiF activities versus non-WBiF activities (80.5 ± 18 vs. 88.3% ± 16.4%; p = 0.13), whereas the PS group had significantly worse satisfaction for WBiF versus non-WBiF activities (71.6 ± 24.6 vs. 87.8% ± 16.6%; p = 0.019). An MS prosthetic design was more stable in the sagittal plane in midflexion compared with a PS design. There was no difference in patient-reported outcomes, although custom survey data suggest improved satisfaction with MS design during WBiF activities.

Changes in acetabular orientation during total hip arthroplasty

AIMS

The aims of this study were to determine the change in pelvic sagittal alignment before, during, and after total hip arthroplasty (THA) undertaken with the patient in the lateral decubitus position, and to determine the impact of these changes on acetabular component position.

PATIENTS AND METHODS

We retrospectively compared the radiological pelvic ratio among 91 patients undergoing THA. In total, 41 patients (46%) were female. The mean age was 61.6 years (sd 10.7) and the mean body mass index (BMI) was 20.0 kg/m² (sd 5.5). Anteroposterior radiographs were obtained: in the standing position preoperatively and at six weeks postoperatively; in the lateral decubitus position after trial reduction intraoperatively; and in the supine position in the post-anaesthesia care unit. Pelvic ratio was defined as the ratio between the vertical distance from the inferior aspect of the sacroiliac (SI) joints to the superior pubic symphysis and the horizontal distance between the inferior aspect of the SI joints. Changes in the apparent component position based on changes in pelvic ratio were determined, with a change of > 5° considered clinically significant. Analyses were performed using Wilcoxon's signed-rank test, with p < 0.05 considered significant.

RESULTS

Intraoperatively, in the lateral decubitus position, the pelvic ratio increased (anterior tilt) in 69.4% of cases, did not change significantly in 20.4%, and decreased (posterior tilt) in 10.2% of cases. When six-week postoperative radiographs were compared with preoperative radiographs, the pelvic ratio decreased in 44.9% of cases, did not change significantly in 42.3%, and increased in 12.8% of cases. This change in alignment correlated with a change in acetabular component version of > 5° in 79.6% of cases intraoperatively and 57.7% of cases at six weeks postoperatively.

CONCLUSION

Changes in pelvic sagittal pelvic position occur throughout THA that, if unaccounted for, introduce errors in acetabular component placement. The use of intraoperative imaging may help the appropriate placement of the acetabular component. Cite this article: Bone Joint J 2019;101-B(6 Supple B):45-50.

ANCHOR surgeon views of patient selection and expectations for periacetabular osteotomy

Preoperative expectations impact shared decision making and patient satisfaction. Surgeon views of patient selection, expected outcomes and patient expectations after periacetabular osteotomy (PAO) for treatment of acetabular dysplasia have not been defined. We assessed surgeon views of patient selection and expected outcomes after PAO. A sample of experienced PAO surgeons participated in semi-structured phone interviews assessing: (i) factors that determine patient candidacy for PAO; (ii) surgeon expectations for PAO outcomes; (iii) surgeon perceptions of patient expectations for PAO outcomes and (iv) surgeon perceptions of discrepancies in surgeon and patient expectations and approaches for reconciling these discrepancies. Twelve surgeons (77% of PAO-performing ANCHOR surgeons) participated. The factors most commonly mentioned in determining patient candidacy for PAO were: symptoms, radiographic findings, absence of arthritis and age. Only one-quarter of the sample mentioned patient expectations as a factor in determining patient candidacy for PAO. The most common surgeon expectations were: pain reduction, joint preservation, function with activities of daily living and return to desired activities. 58% of surgeons felt that surgeon and patient expectations align most of the time. Common expectation discrepancies included return to unrestricted activities and complete pain relief. Detailed discussion was the most commonly employed strategy to resolve expectation discrepancies. PAO surgeons felt that patient expectations of complete pain relief and return to unrestricted activities were misaligned with their own expectations. Development of an expectations survey may facilitate shared decision making.

Complications associated with combined surgical hip dislocation and periacetabular osteotomy for complex hip deformities

Surgical hip dislocation (SD) and periacetabular osteotomy (PAO) are well-described treatments for femoroacetabular impingement (FAI) and acetabular dysplasia, respectively. Occasionally, complex deformities require a combined SD/PAO; the morbidity of performing both procedures in a single stage has not been fully investigated. We performed a retrospective review of a consecutive group of patients undergoing combined SD/PAO to investigate the incidence and character of perioperative complications. Forty-five patients (46 hips) were identified. Perioperative complications were graded by the modified Clindo-Davien complication scheme. Mean follow-up was 36 months (range 12-128), and no patients were lost to follow-up. Six complications occurred in six hips (13%). Four (8.7%) complications were minor (Grades I or II): one Brooker Grade III heterotopic ossification requiring no treatment, one superior pubic ramus nonunion requiring no treatment and two superficial wound infections requiring antibiotics. Two (4.3%) complications were major (Grades III or IV): one coxa saltans interna and labral tear requiring hip arthroscopy with labral repair and iliopsoas lengthening, and one deep surgical site infection requiring irrigation and debridement followed by development of arthritis requiring conversion to arthroplasty. The average Harris hip score improved from 62 ± 13 preoperatively to 80 ± 19 at final follow-up. Except for the single joint replacement, there were no long-term disabilities. There were no major neurovascular injuries, osteonecrosis, fractures or trochanteric nonunions. Combined SD/PAO for the treatment of complex, concomitant deformities of the proximal femur and acetabulum is associated with an acceptable risk of complications. The vast majority of complications that occurred were managed without permanent disability. Level of Evidence: IV.

Choices, Compromises, and Controversies in Total Knee Arthroplasty

Although condylar total knee arthroplasty (TKA) has been performed for almost 40 years, many choices, compromises, and controversies remain. In the effort to provide optimal care and beneficial, enduring treatment for an expanding population of patients with debilitating arthritis of the knee and who are using ever-diminishing provider and financial resources, orthopaedic surgeons must carefully examine the available evidence to determine best practices. First, there is debate as to who should be a candidate for TKA. Beyond the established criteria of disease severity, should all patients who can benefit from TKA undergo the procedure, or should surgeons develop exclusion criteria based on complication risk? Current concepts for identifying and managing modifiable risk factors should be considered. Second, there is debate regarding the choice of TKA versus partial knee arthroplasty to manage unicompartmental arthritis. Third, surgeons continue to debate the ideal implant design for primary condylar TKA, whether to proceed with an anatomic approach of preserving one or both cruciate ligaments or a functional approach of resecting and substituting for the cruciate ligaments in various ways.

Nephrotoxicity After the Treatment of Periprosthetic Joint Infection With Antibiotic-Loaded Cement Spacers

BACKGROUND

Treatment of periprosthetic joint infections commonly involves insertion of an antibiotic-loaded cement spacer (ACS). The risk for acute kidney injury (AKI) related to use of antibiotic spacers has not been well defined. We aimed to identify the incidence of and risk factors for AKI after placement of an ACS.

METHODS

We performed a prospective cohort study of patients with an infected primary total hip or knee arthroplasty treated with ACSs with vancomycin, gentamicin, and tobramycin. Serum creatinine and glomerular filtration rate data were collected at baseline and weekly intervals for 8 weeks. Patients were classified into Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease (RIFLE) stages to determine incidence of AKI. Risk factors for kidney injury were identified via regression analysis.

RESULTS

A total of 37 patients (20 total knee arthroplasty and 17 total hip arthroplasty) were included. During the 8 weeks after ACS placement, 10 patients (27%) fit RIFLE criteria for kidney injury and 2 patients (5%) fit RIFLE criteria for kidney failure. No baseline patient characteristics were associated with development of AKI.

CONCLUSION

Patients should be monitored closely for development of AKI after placement of ACSs for the treatment of periprosthetic joint infection. Further research into minimizing risk for AKI is warranted.

Systemic Absorption of Antibiotics From Antibiotic-Loaded Cement Spacers for the Treatment of Periprosthetic Joint Infection

BACKGROUND

Two-stage treatment of periprosthetic joint infections involves placement of high-dose antibiotic-loaded cement spacers (ACSs). Reports of ACS-induced nephrotoxicity have raised concern regarding systemic absorption of antibiotics after ACS placement. We sought to characterize the serum concentrations of antibiotics that occur after ACS placement.

METHODS

We performed a prospective study of patients with an infected primary total hip (THA) or knee arthroplasty (TKA) treated with standardized ACSs with vancomycin, gentamicin, and tobramycin. Serum antibiotic levels were collected weekly for 8 weeks.

RESULTS

Twenty-one patients (10 THA, 11 TKA) were included. Mean serum gentamicin levels ranged between 0.275±0.046 and 0.364±0.163 mg/L; mean serum tobramycin levels ranged from 0.313±0.207 to 0.527±0.424 mg/L; and mean serum vancomycin levels ranged from 5.46±6.6 to 15.34±9.6 mg/L. Serum antibiotic levels were detectable throughout the 8-week duration of ACS treatment. Regression analysis found that diabetes (coefficient 6.73, 95% CI 0.92-12.54, P < .05), blood urea nitrogen (coefficient 0.83, 95% CI 0.45-1.22, P < .001), number of cement doses (coefficient 3.71, 95% CI 0.76-6.66, P < .05), and use of systemic vancomycin (coefficient 6.24, 95% CI 2.72-9.75, P < .001) correlated with serum vancomycin levels. Patient age (coefficient -0.01, 95% CI -0.02 to 0, P < .01) and male sex (coefficient 0.20, 95% CI 0-0.41, P < .05) correlated with serum aminoglycoside level.

CONCLUSION

Systemic absorption of antibiotics from high-dose ACS persists for at least 8 weeks. Patients should be monitored closely for complications related to systemic absorption of antibiotics from ACS treatment.

Risk Factors for Postoperative Infections After Single-Level Lumbar Fusion Surgery

STUDY DESIGN

Retrospective multivariate analysis of a prospectively collected, multicenter database.

OBJECTIVE

To identify patient characteristics and perioperative risk factors associated with postoperative infectious complications after single-level lumbar fusion (SLLF) surgery.

SUMMARY OF BACKGROUND DATA

Postoperative infection is a known complication after lumbar fusion. Risk factors for infectious complications after lumbar fusion have not been investigated using select set of SLLF procedures.

METHODS

Patients who underwent SLLF between 2006 and 2011 were identified from the American College of Surgeons National Surgical Quality Improvement Program database. Multivariate logistic regression analyses were performed to identify pre- and intraoperative risk factors associated with postoperative infection.

RESULTS

A total of 3353 patients were analyzed in this study. Overall, 173 (5.2%) patients experienced a postoperative infection, including 86 (2.6%) surgical site infections (SSIs) and 111 (3.3%) non-SSI infectious complications (pneumonia, urinary tract infection, sepsis/septic shock). Twenty-four (0.7%) patients experienced both SSI and non-SSI infectious complications. Postoperative SSI were associated with obesity (odds ratio [OR], 1.628; 95% confidence interval [CI], 1.042-2.544), American Society of Anesthesiologists class more than 2 (OR, 2.078; 95% CI, 1.309-3.299), and operative time more than 6 hours (OR, 2.573; 95% CI, 1.310-5.056). Risk factors for non-SSI infectious complications included age (60-69 yr; OR, 3.279; 95% CI, 1.541-6.980; and ≥70 yr; OR, 3.348; 95% CI, 1.519-7.378), female sex (OR, 1.791; 95% CI, 1.183-2.711), creatinine more than 1.5 mg/dL (OR, 2.400; 95% CI, 1.138-5.062), American Society of Anesthesiologists class more than 2 (OR, 1.835; 95% CI, 1.177-2.860), and operative time more than 6 hours (OR, 3.563; 95% CI, 2.082-6.097).

CONCLUSION

Across a wide study population, we identified that obesity, advanced American Society of Anesthesiologists classification, and longer operative time were predictive of postoperative SSI. We also demonstrated that increased age, female sex, serum creatinine more than 1.5 mg/dL, and prolonged operative duration are associated with non-SSI infectious complications after SLLF. Continued efforts to elucidate and optimize perioperative risk factors are warranted to improve outcomes in patients requiring spinal fusion.

LEVEL OF EVIDENCE

3.

The Impact of Metabolic Syndrome on 30-Day Complications Following Total Joint Arthroplasty

BACKGROUND

The arthroplasty population increasingly presents with comorbid conditions linked to elevated risk of postsurgical complications. Current quality improvement initiatives require providers to more accurately assess and manage risk presurgically. In this investigation, we assess the effect of metabolic syndrome (MetS), as well as the effect of body mass index (BMI) within MetS, on the risk of complication following hip and knee arthroplasty.

METHODS

We queried the American College of Surgeons National Surgical Quality Improvement Program database for total hip or knee arthroplasty cases. Thirty-day rates of Centers for Medicare and Medicaid Services (CMS)-reportable complications, wound complications, and readmissions were compared between patients with and without a diagnosis of MetS using multivariate logistic regression. Arthroplasty cases with a diagnosis of MetS were further stratified according to World Health Organization BMI class, and the role of BMI within the context of MetS was assessed.

RESULTS

Of the 107,117 included patients, 11,030 (10.3%) had MetS. MetS was significantly associated with CMS complications (odds ratio [OR] = 1.415; 95% confidence interval [CI], 1.306-1.533; P < .001), wound complications (OR = 1.749; 95% CI, 1.482-2.064; P < .001), and readmission (OR = 1.451; 95% CI, 1.314-1.602; P < .001). When MetS was assessed by individual BMI class, the MetS + BMI >40 group was associated with significantly higher risk of CMS complications, wound complications, and readmission compared to the lower MetS BMI groups.

CONCLUSION

MetS is an independent risk factor for CMS-reportable complications, wound complications, and readmission following total joint arthroplasty. The risk attributable to MetS exists irrespective of obesity class and increases as BMI increases.

Intra-Articular Vancomycin Powder Eliminates Methicillin-Resistant S. aureus in a Rat Model of a Contaminated Intra-Articular Implant

BACKGROUND

Periprosthetic joint infection following hip and knee arthroplasty leads to poor outcomes and exorbitant costs. Topical vancomycin powder has been shown to decrease infection in many procedures such as spine surgery. The role of vancomycin powder in the setting of total joint arthroplasty remains undefined. Our aim was to evaluate the efficacy of intra-articular vancomycin powder in preventing infection in a rat model of a contaminated intra-articular implant.

METHODS

Thirty-two female Sprague-Dawley rats underwent knee arthrotomy and implantation of a femoral intramedullary wire with 1 mm of intra-articular communication. The knee joint was also inoculated with 1.5 × 10 colony forming units (CFU)/mL of methicillin-resistant Staphylococcus aureus (MRSA). Four treatment groups were studied: (1) no antibiotics (control), (2) preoperative systemic vancomycin, (3) intra-articular vancomycin powder, and (4) both systemic vancomycin and intra-articular vancomycin powder. The animals were killed on postoperative day 6, and distal femoral bone, joint capsule, and the implanted wire were harvested for bacteriologic analysis. Statistical analyses were performed using Wilcoxon rank sum and Fisher exact tests.

RESULTS

There were no postoperative deaths, wound complications, signs of vancomycin-related toxicity, or signs of systemic illness in any of the treatment groups. There were significantly fewer positive cultures in the group that received vancomycin powder in combination with systemic vancomycin compared with the group that received systemic vancomycin alone (bone: 0% versus 75% of 8, p = 0.007; Kirschner wire: 0% versus 63% of 8, p = 0.026; whole animal: 0% versus 88% of 8, p = 0.01). Only animals that received both vancomycin powder and systemic vancomycin showed evidence of complete elimination of bacterial contamination.

CONCLUSIONS

In a rat model of a contaminated intra-articular implant, use of intra-articular vancomycin powder in combination with systemic vancomycin completely eliminated MRSA bacterial contamination. Animals treated with systemic vancomycin alone had persistent MRSA contamination.

CLINICAL RELEVANCE

This animal study presents data suggesting that the use of intra-articular vancomycin powder for reducing the risk of periprosthetic joint infections should be investigated further in clinical studies.

The Interaction of Obesity and Metabolic Syndrome in Determining Risk of Complication Following Total Joint Arthroplasty

BACKGROUND

The arthroplasty population is increasingly comorbid, and current quality improvement initiatives demand accurate risk stratification. Metabolic syndrome (MetS) has been identified as a risk factor for adverse events after arthroplasty; however, its interaction with obesity in contributing to risk is unclear.

METHODS

A retrospective analysis of all Medicare patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) at a single institution from 2009 to 2013 investigated the interaction between MetS, body mass index (BMI), and risk for Centers for Medicare and Medicaid Services (CMS)-reportable complications, readmission, and discharge disposition.

RESULTS

A total of 1462 patients (942 TKA, 538 THA) were included, of which 16.2% had MetS. Regression analysis found that MetS was significantly related to risk of CMS complications (odds ratio [OR] = 1.96, 95% confidence interval [CI] 1.16-3.31, P = .012) and nonhome discharge (OR = 1.78, 95% CI 1.39-2.27, P < .001), but not readmission (OR = 1.23, 95% CI 0.7-2.18, P = .485). Within the MetS cohort, increasing BMI was not associated with increasing complications (P = .726) or readmissions (P = .206) but was associated with nonhome discharge (OR = 1.191 per unit increase in BMI, 95% CI 1.038-1.246, P = .001).

CONCLUSION

MetS increases risk for CMS-reportable complications and nonhome discharge disposition after THA and TKA regardless of BMI. Obesity is of less value than MetS in assessing overall risk for complication after THA and TKA.

Perioperative Outcomes Following Unilateral Versus Bilateral Total Knee Arthroplasty

Simultaneous bilateral total knee arthroplasty (SB-TKA) is potentially a cost saving manner of caring for patients with bilateral symptomatic knee arthritis. We performed a retrospective analysis using the 2010-2012 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) to evaluate the risk of perioperative complication following SB-TKA. Demographic characteristics, comorbidities, and 30-day complication rates were studied using a propensity score-matched analysis comparing patients undergoing unilateral TKA and SB-TKA. A total of 4489 patients met the inclusion criteria, of which 973 were SB-TKA. SB-TKA was associated with increased overall complications (P = 0.023), medical complications (P = 0.002) and reoperation (OR 2.12, P = 0.020). Further, total length of hospital stay (4.0 vs 3.4 days, P < 0.001) was significantly longer following bilateral surgery.

Can the American College of Surgeons Risk Calculator Predict 30-Day Complications After Knee and Hip Arthroplasty?

Accurate risk stratification of patients undergoing total hip (THA) and knee (TKA) arthroplasty is essential in the highly scrutinized world of pay-for-performance, value-driven healthcare. We assessed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) surgical risk calculator's ability to predict 30-day complications using 1066 publicly-reported Medicare patients undergoing primary THA or TKA. Risk estimates were significantly associated with complications in the categories of any complication (P = .005), cardiac complication (P < .001), pneumonia (P < .001) and discharge to skilled nursing facility (P < .001). However, predictability of complication occurrence was poor for all complications assessed. To facilitate the equitable provision and reimbursement of patient care, further research is needed to develop accurate risk stratification tools in TKA and THA surgery.

Osteochondroma With Contiguous Bronchogenic Cyst of the Scapula

Osteochondroma is a benign bone tumor composed of a bony protrusion with an overlying cartilage cap. Osteochondromas arise in the scapula in 3% to 5% of cases, making them the most common benign bone tumor in this location. Scapular osteochondromas cause various pathologies of the shoulder girdle, including snapping scapula syndrome, chest wall deformity, shoulder impingement, and bursa formation. Bronchogenic cyst is an exceedingly rare finding in the periscapular area. It is a congenital cystic mass lined by tracheobronchial structures and respiratory epithelium. To our knowledge, there are no reports of a contiguous osteochondroma and bronchogenic cyst. A 12-month-old boy presented with an incidentally noted mass on the spine of the scapula, which drained scant, clear fluid through an adjacent pinprick-sized hole. Imaging revealed an exostosis with an adjacent cystic mass. The mass and cyst were excised en bloc, and histopathologic examination confirmed the diagnosis of osteochondroma with contiguous bronchogenic cyst. In this case, we present the report of a novel dual lesion.

Impact of Resident Involvement on Orthopaedic Surgery Outcomes: An Analysis of 30,628 Patients from the American College of Surgeons National Surgical Quality Improvement Program Database

BACKGROUND

Operative procedural training is a key component of orthopaedic surgery residency. The influence of intraoperative resident participation on the outcomes of surgery has not been studied extensively using large, population-based databases.

METHODS

We identified 30,628 patients who underwent orthopaedic procedures from the 2011 American College of Surgeons National Surgical Quality Improvement Program. Outcomes as measured by perioperative complications, readmission rates, and mortality within thirty days were compared for cases with and without intraoperative resident involvement.

RESULTS

Logistic regression with propensity score analysis revealed that intraoperative resident participation was associated with decreased rates of overall complications (odds ratio, 0.717 [95% confidence interval, 0.657 to 0.782]), medical complications (odds ratio, 0.723 [95% confidence interval, 0.661 to 0.790]), and mortality (odds ratio, 0.638 [95% confidence interval, 0.427 to 0.951]). Resident presence in the operating room was not predictive of wound complications (odds ratio, 0.831 [95% confidence interval, 0.656 to 1.053]), readmission (odds ratio, 0.962 [95% confidence interval, 0.830 to 1.116]), or reoperation (odds ratio, 0.938 [95% confidence interval, 0.758 to 1.161]). A second analysis by propensity score stratification into quintiles grouped by similar probability of intraoperative resident presence showed resident involvement to correlate with decreased rates of overall and medical complications in three quintiles, but increased rates of overall and medical complications in one quintile. All other outcomes were equivalent across quintiles.

CONCLUSIONS

Orthopaedic resident involvement during surgical procedures is associated with lower risk of perioperative complications and mortality in the National Surgical Quality Improvement Program database. The results support resident participation in the operative care of orthopaedic patients.

LEVEL OF EVIDENCE

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