Faculty Bibliography

BACKGROUND/UNASSIGNED:Surgeons with high volume (HV) of total hip arthroplasty (THA) have seen better outcomes than low volume (LV) surgeons. However, literature regarding surgeon volume and outcomes in morbidly obese THA patients is scarce. This study examines the association between surgeon volume with THA in morbidly obese patients (body mass index ≥40) and their clinical outcomes. METHODS/UNASSIGNED:We retrospectively reviewed all morbidly obese patients who underwent primary THA at our institution between March 2012 and July 2020 with 2 years of follow-up. Clinical outcomes were compared between the HV (HVa, top quartile of surgeons with the highest overall yearly THA volume) and LV (LVa) surgeons. Similar analysis was run comparing HV of morbidly obese THA (HVo, top quartile of surgeons with the highest yearly morbidly obese THA volume) and LV of morbidly obese THA (LVo) surgeons. RESULTS/UNASSIGNED:Six hundred and forty-three patients and 33 surgeons were included. HVa surgeons had significantly shorter length of stay and increased home discharge. HVa and HVo surgeons had significantly shorter operative times. There were no significant differences in overall 90-day major and minor complications or clinical differences in patient-reported outcomes. Revision rates and freedom from revisions did not differ between groups at 2-year follow-up. CONCLUSIONS/UNASSIGNED:HVa surgeons had significantly lower length of stay and operative times and increased discharge to home. There was no significant decrease in complications or revisions in either comparison model. Complications, revision rates, and patient satisfaction in morbidly obese patients who undergo THA may be independent of surgeon volume.

PURPOSE/OBJECTIVE:Soft tissue balancing is an important step in a total knee procedure, carried out manually, or using an indicator. The purpose of this study was to evaluate our design of 3D printed Balancer, and demonstrate how it could be used at surgery. PROCEDURES/METHODS:When inserted between the femur and tibia, the Balancer displayed the forces acting across the lateral and medial compartments, indicated by pointers at the end of the handle. A loading rig was used to measure the pointer deflections for different forces applied at different locations on the condyle surfaces. Repeatability and reproducibilty were evaluated. The Balancer was tested in six fresh knee specimens using a surgical simulation rig. MAIN FINDINGS/RESULTS:Pointer deflections of up to 12 millimeters occurred for less than 1 mm displacements at the condyle surfaces. Reproducibility tests showed a standard deviation of 14% at lower loads, reducing to only 4% at higher loads. Mean pointer deflections were within 8% for forces applied at ±10 mm AP, and +5/-3 mm in an ML direction, relative to the neutral contact point. In specimens, most lateral to medial force differences could be corrected by a 2° change in frontal plane angle of the tibial resection. Effects of ligament releases were also demonstrated. PRINCIPAL CONCLUSIONS/CONCLUSIONS:The 3D printed Balancer was easy to use, and provided the surgeon with lateral and medial force data over a full range of flexion, enabling possible corrective procedures to be specified.

BACKGROUND:Supervised machine learning techniques have been increasingly applied to predict patient outcomes after hip and knee arthroplasty procedures. The purpose of this study was to systematically review the applications of supervised machine learning techniques to predict patient outcomes after primary total hip and knee arthroplasty. METHODS:A comprehensive literature search using the electronic databases MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews was conducted in July of 2021. The inclusion criteria were studies that utilized supervised machine learning techniques to predict patient outcomes after primary total hip or knee arthroplasty. RESULTS:Search criteria yielded n = 30 relevant studies. Topics of study included patient complications (n = 6), readmissions (n = 1), revision (n = 2), patient-reported outcome measures (n = 4), patient satisfaction (n = 4), inpatient status and length of stay (LOS) (n = 9), opioid usage (n = 3), and patient function (n = 1). Studies involved TKA (n = 12), THA (n = 11), or a combination (n = 7). Less than 35% of predictive outcomes had an area under the receiver operating characteristic curve (AUC) in the excellent or outstanding range. Additionally, only 9 of the studies found improvement over logistic regression, and only 9 studies were externally validated. CONCLUSION/CONCLUSIONS:Supervised machine learning algorithms are powerful tools that have been increasingly applied to predict patient outcomes after total hip and knee arthroplasty. However, these algorithms should be evaluated in the context of prognostic accuracy, comparison to traditional statistical techniques for outcome prediction, and application to populations outside the training set. While machine learning algorithms have been received with considerable interest, they should be critically assessed and validated prior to clinical adoption.

BACKGROUND:Total hip arthroplasty is a common surgical treatment for elderly patients with osteoporosis, particularly in postmenopausal women. In such cases, highly porous acetabular components are a favorable option in achieving osseointegration. However, further discussion is needed if use of such acetabular components is justified under the condition of normal bone mass. AIM/OBJECTIVE:To determine the features of osseointegration of two different types of titanium implants [3-dimensional (3D)-printed and plasma-coated titanium implants] in bone tissue of a distal metaphysis in a rat femur model. METHODS:This study was performed on 20 white male laboratory rats weighing 300-350 g aged 6 mo. Rats were divided into two groups of 10 animals, which had two different types of implants were inserted into a hole defect (2 × 3 mm) in the distal metaphysis of the femur: Group I: 3D-printed titanium implant (highly porous); Group II: Plasma-coated titanium implant. After 45 and 90 d following surgery, the rats were sacrificed, and their implanted femurs were extracted for histological examination. The relative perimeter (%) of bone trabeculae [bone-implant contact (BIC%)] and bone marrow surrounding the titanium implants was measured. RESULTS:= 0.049) compared to the relative perimeter of bone marrow in group II. CONCLUSION/CONCLUSIONS:The use of a highly porous titanium implant, manufactured with 3D printing, for acetabular components provides increased osseointegration compared to a plasma-coated titanium implant.

Total knee arthroplasty (TKA) in the setting of a previous ipsilateral hip fusion/arthrodesis is an uncommon and challenging procedure. There is little information available in the literature on the challenges and techniques available to perform TKA in these patients. For a traditional TKA procedure, the patient is placed in the supine position and various knee-positioning devices are used to allow for adequate knee and hip flexion, which is required for surgical exposure and tibia preparation. Ipsilateral hip arthrodesis presents two major challenges: (1) Hip flexion is crucial for adequate knee flexion while the patient is supine during the TKA procedure, and (2) the use of advanced technology, specifically computer navigation and robotic-assisted surgery techniques, is limited due to the inability to acquire the hip center of rotation during surgery, due to the lack of hip motion. Therefore, equipment and positioning must be adjusted by the surgeon to facilitate TKA in these patients. This article reports the case of a 72-year-old male patient with a long-standing, painless right hip arthrodesis, presenting with end-stage osteoarthritis of the right knee, leg-length discrepancy, and an 11.6° difference between the mechanical and anatomical axes of the femur. We describe the unique surgical planning as well as the surgical positioning options that allow for adequate knee flexion and proper surgical exposure. Furthermore, we describe a novel method of computer-assisted navigation for intra-operative planning and execution utilizing a reflected tibia as a template for the distal femoral cut.

BACKGROUND:Few studies have assessed how socioeconomic status (SES) influences patient-reported outcomes (PROMs) after total knee arthroplasty (TKA). This study evaluated the impact of patient median ZIP code income levels on PROMs after TKA. METHODS:We retrospectively reviewed patients at our institution undergoing primary, unilateral TKA from 2017 to 2020. Patients who did not have one-year postoperative PROMs were excluded. Patients were stratified based on the quartile of their home ZIP code median income from United States Census Bureau data. There were 1,267 patients included: 98 in quartile 1 (median income ≤ $46,308) (7.7%); 126 in quartile 2 (median income $46,309-$57,848) (10.0%); 194 in quartile 3 (median income $57,849-$74,011) (15.7%); and 849 in quartile 4 (median income ≥ $74,012) (66.4%). We collected baseline demographic data, 2-year outcomes, and PROMs preoperatively, as well as at 12 weeks and one year, postoperatively. RESULTS:The Knee Injury and Osteoarthritis Outcome Score for Joint Replacement was significantly higher in quartile 4 preoperatively (P < .001), 12 weeks postoperatively (P < .001), and one year postoperatively (P < .001). There were no significant differences in delta improvements of Knee Injury and Osteoarthritis Outcome Score for Joint Replacement from preoperative to 12 weeks or one year postoperatively. There were no significant differences in lengths of stay, discharge dispositions, readmissions, or revisions. CONCLUSION/CONCLUSIONS:Patients from lower income areas have slightly worse knee function preoperatively and worse outcomes following TKA. However, improvements in PROMs throughout the first year postoperatively are similar across income quartiles, suggesting that patients from lower income quartiles achieve comparable therapeutic benefits from TKA. LEVEL III EVIDENCE/METHODS:Retrospective Cohort Study.

INTRODUCTION/BACKGROUND:Hip resurfacing arthroplasty (HRA) is a surgical option with positive outcomes at medium-term follow-up for young, active patients with osteoarthritis. However, early failures of HRA often occur due to improper implant placement. The purpose of this study was to assess the utility of computer-assisted navigation in the effort to optimize implant positioning following HRA. MATERIALS AND METHODS/METHODS:A retrospective analysis of 262 consecutive HRAs at a single institution was performed. Radiographic analysis included measurements of cup inclination and anteversion, leg length restoration (LLR), and offset. Cup position was evaluated based on placement within Lewinnek parameters and the surgeon's preferred anteversion (10° to 20°). Chi-squared and unpaired Student's t-test were performed for all categorical and continuous variables, respectively. RESULTS:One hundred fifty-six cases were performed using conventional technique and 106 cases used computernavigation. Computer-assisted HRA (caHRA) had a longer mean surgical time (129 vs. 110 minutes; p < 0.001) but shorter average LOS (1.1 vs. 1.5 days; p < 0.001). Cup position was within the surgeon-preferred target zone in 47% of caHRA versus 22% of conventional HRA (p = 0.0001). Cup position fell within the Lewinnek safe zone in 86% of caHRA versus 60% of conventional HRA (p < 0.001). Global offset was reduced by a mean of 6.4 mm in caHRA versus 8.4 mm (p = 0.036). No differences in rates of complication (p = 0.406), reoperation (p = 1.00), or 90-day readmission (p = 0.568) were observed. CONCLUSION/CONCLUSIONS:Computer-assisted technology in HRA allows for comparable clinical outcomes to conventional technique. Cup position accuracy and precision is improved by computer navigation in HRA.

BACKGROUND:Many studies have demonstrated that in patients whose primary language is not English, outcomes after orthopaedic surgery are worse compared to primary English speakers. The goal of this study was to compare perioperative outcomes in patients undergoing total knee arthroplasty (TKA) who prefer English as their first language versus those who prefer a different language. METHODS:We retrospectively reviewed all patients who underwent primary TKA from May 2012 to July 2021. Patients were separated into two groups based on whether English was their preferred primary language (PPL). Of the 13,447 patients who underwent primary TKA, 11,290 reported English as their PPL and 2,157 preferred a language other than English. Patients whose PPL was not English were further stratified based on whether they requested interpreter services. Multiple regression analyses were performed to determine the significance of perioperative outcomes while controlling for demographic differences. RESULTS:Our analysis found that non-English PPL patients had significantly lower rates of readmission (p=0.040), overall revision (p=0.028), and manipulation under anesthesia (MUA; p=0.025) within 90 days postoperatively. Sub analyses of the non-English PPL group showed that those who requested interpreter services had significantly lower one year revision (p<0.001) and overall MUA (p=0.049) rates. CONCLUSION/CONCLUSIONS:Our results demonstrate that TKA patients who communicated in English without an interpreter were significantly more likely to undergo revision, readmission, and MUA. These findings may suggest that language barriers may make it more difficult to identify postoperative problems or concerns in non-English speakers, which may limit appropriate postoperative care.

INTRODUCTION/BACKGROUND:Reduced bone mineral density (BMD) and disruption of normal bony architecture are the characteristics of osteopenia and osteoporosis and in patients undergoing total hip arthroplasty (THA) may cause failure of trabecular ingrowth. The purpose of this study is to evaluate the impact of reduced BMD on outcomes following primary elective THA. METHODS:A retrospective chart review of 650 elective THAs with a DEXA scan in their electronic health record (EHR) from 2011 to 2020 was conducted at an urban, academic center and a regional, health center. Patients were separated into three cohorts based on their t-score and the World Health Organizations definitions: normal (t-score ≥ - 1), osteopenia (t-score < - 1.0 and > - 2.5), and osteoporosis (t-score ≤ - 2.5). Demographic and outcome data were assessed. Subsidence was assessed for patients with non-cemented THAs. Regression models were used to account for demographic differences. RESULTS:650 elective THAs, of which only 11 were cemented, were included in the study. Patients with osteopenia and osteoporosis were significantly older than those without (p = 0.002 and p < 0.0001, respectively) and had a lower BMI (p < 0.0001 and p < 0.0001, respectively). PFx was significantly greater in patients with osteoporosis when compared to those with normal BMD (6.5% vs. 1.0%; p = 0.04). No such difference was found between osteoporotic and osteopenic patients. The revision rate was significantly higher for osteoporotic patients than osteopenic patients (7.5% vs. 1.5%; p = 0.04). No such difference was found between the other comparison groups. CONCLUSION/CONCLUSIONS:Patients with osteoporosis were older with reduced BMI and had increased PFx after non-cemented elective THA. Understanding this can help surgeons formulate an appropriate preoperative plan for the treatment of patients with osteoporotic bone undergoing elective THA.

BACKGROUND:Removal of total knee arthroplasty (TKA) from the inpatient only list has led to a greater focus on outpatient (OP) procedures. However, the impact of OP-centered models in at-risk patients is unclear. Therefore, the current analysis investigated the effect of conversion from OP to inpatient (IP) status on postoperative outcomes and determined which factors put patients at risk for status change postoperatively. METHODS:We retrospectively reviewed all patients who underwent a primary TKA at our institution between January 2, 2018, and April 26, 2022. All patients included were originally scheduled for OP surgery and were separated based on conversion to IP status postoperatively. Multiple regression analyses were used to determine the significance of all perioperative variables. Modeling via binary logistic regressions was used to determine factors predictive of status conversion. RESULTS:Of the 2,313 patients originally designated for OP TKA, 627 (27.1%) required a stay of 2 midnights or longer. Patients in the IP group had significantly higher facility discharge rates (P < .001) compared to the OP group. Factors predictive of conversion included age of 65 years and older (P < .001), women (P < .001), arriving at the postanesthesia care unit after 12 pm (P < .001), body mass index greater than 30 (P = .004), and Charlson Comorbidity Index of 4 and higher (P = .004). Being the first case of the day (P < .001) and being married (P < .001) were both protective against conversion. CONCLUSION:Certain intrinsic patient factors may predispose a patient to an IP stay, and an understanding of predisposing factors which could lead to IP conversion may improve perioperative planning moving forward.