Faculty Bibliography

The management of acetabular bone loss during revision arthroplasty is a challenging problem. Not only are there a wide variety of potential defects, but the location of these defects can also drastically change the hip center of rotation, stability, and biomechanics. First, the assessment of the severity and location of bone loss preoperatively is highlighted as it is imperative to evaluate the acetabular bone stock remaining. It is especially important to determine how to identify a pelvic discontinuity. Various classification systems are discussed to help surgeons adequately assess and evaluate these defects. There are also numerous implants and treatment strategies available to manage the problem, all of which are determined by that preoperative assessment and classification. We review the history of managing these defects and how management has evolved into modern designs, including but not limited to structural allograft, distraction arthroplasty, jumbo cups, metal augments, cup-cages, and custom triflanges. This review then describes the up-to-date clinical results of these various techniques, highlighting the surgical execution needed to obtain a successful result. By describing the preoperative assessment, the acetabular defect classifications, and proposed evidence-based treatment algorithms, we hope that this review will enhance the understanding of these challenging reconstructions in the setting of acetabular bone defects.

INTRODUCTION/BACKGROUND:Loosening and migration are common modes of aseptic failure following complex revision total knee arthroplasty (rTKA). Metaphyseal cones allow surgeons to negotiate the loss of femoral and tibial bone stock while obtaining stable bony fixation. This study examines the mid-term functional and radiographic outcomes in patients undergoing rTKA utilizing a novel metaphyseal cone system with stems of variable length and fixation methods. METHODS:This two-center retrospective study examined all patients who underwent rTKA with a novel porous, titanium tibial or femoral cone in combination with a stem of variable length and fixation who had a minimum follow-up of 2-years. Outcome analysis was separated into tibial and femoral cones as well as the stem fixation method (hybrid vs. fully cemented). RESULTS:Overall, 123 patients who received 156 cone implants were included (74 [60.2%] tibial only, 16 [13.0%] femoral only, and 33 [26.8%] simultaneous tibial and femoral) with a mean follow-up of 2.76 ± 0.66 years. At 2-years of follow-up the total cohort demonstrated 94.3% freedom from all-cause re-revisions, 97.6% freedom from aseptic re-revisions, and 99.4% of radiographic cone osteointegration. All-cause revision rates did not differ between stem fixation techniques in both the tibial and femoral cone groups. CONCLUSION/CONCLUSIONS:The use of a novel porous titanium femoral and tibial metaphyseal cones combined with stems in patients with moderate to severe bone defects undergoing complex revision total knee arthroplasty confers excellent results independent of stem fixation technique. LEVEL OF EVIDENCE/METHODS:IV, case series.

INTRODUCTION/BACKGROUND:Increasing age and hip fractures are considered risk factors for post-operative complications in total hip arthroplasty (THA). Consequently, older adults undergoing THA due to hip fracture may have different outcomes and require additional healthcare resources than younger patients. This study aimed to identify the influence of age on discharge disposition and 90-day outcomes of THA performed for hip fractures in patients ≥ 80 years to those aged < 80. MATERIALS AND METHODS/METHODS:A retrospective review of 344 patients who underwent primary THA for hip fracture from 2011 to 2021 was conducted. Patients ≥ 80 years old were propensity-matched to a control group < 80 years old. Patient demographics, length of stay (LOS), discharge disposition, and 90-day post-operative outcomes were collected and assessed using Chi-square and independent sample t tests. RESULTS:A total of 110 patients remained for matched comparison after propensity matching, and the average age in the younger cohort (YC, n = 55) was 67.69 ± 10.48, while the average age in the older cohort (OC, n = 55) was 85.12 ± 4.77 (p ≤ 0.001). Discharge disposition differed between the cohorts (p = 0.005), with the YC being more likely to be discharged home (52.7% vs. 27.3%) or to an acute rehabilitation center (23.6% vs. 16.4%) and less likely to be discharged to a skilled nursing facility (21.8% vs. 54.5%). 90-day revision (3.6% vs. 1.8%; p = 0.558), 90-day readmission (10.9% vs. 14.5%; p = 0.567), 90-day complications (p = 0.626), and 90-day mortality rates (1.8% vs 1.8%; p = 1.000) did not differ significantly between cohorts. CONCLUSION/CONCLUSIONS:While older patients were more likely to require a higher level of post-hospital care, outcomes and perioperative complication rates were not significantly different compared to a younger patient cohort. Payors need to consider patients' age in future payment models, as discharge disposition comprises a large percentage of post-discharge expenses. LEVEL OF EVIDENCE/METHODS:Level III, Retrospective Cohort Study.

Background:National projections of future joint arthroplasties are useful for understanding the changing burden of surgery and related outcomes on the health system. The aim of this study is to update the literature by producing Medicare projections for primary total joint arthroplasty (TJA) procedures until 2040 and 2060.Methods:The present study used data from the Centers for Medicare & Medicaid Services (CMS) Medicare/Medicaid Part B National Summary and combined procedure counts with use of Current Procedural Terminology (CPT) codes to identify whether the procedure was a primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) procedure. In 2019, the annual volume of primary TKA was 480,958 and that of primary THA was 262,369. These values formed a baseline from which we generated point forecasts for 2020-2060 and 95% forecast intervals (FIs).Results:Between 2000 and 2019, the estimated annual volume of THA increased by 177% and that of TKA increased by 156% on average. Regression analysis projected an annual growth rate of 5.2% for THA and 4.44% for TKA. Based on these yearly projected increases, an estimated increase of 28.84% and 24.28% is expected for each 5-year period after 2020 for THA and TKA, respectively. By 2040, the number of THAs is projected to be 719,364 (95% FI, 624,766 to 828,286) and the number of TKA is projected to be 1,222,988 (95% FI, 988,714 to 1,512,772). By 2060, the number of THAs is projected to be 1,982,099 (95% FI, 1,624,215 to 2,418,839) and the number of TKAs is projected to be 2,917,959 (95% FI, 2,160,951 to 3,940,156). In 2019, Medicare data showed that THA constituted approximately 35% of TJA procedures performed.Conclusions:Based on 2019 total volume counts, our model forecasts an increase in THA procedures of 176% by 2040 and 659% by 2060. The estimated increase for TKA is projected to be 139% by 2040 and 469% by 2060. An accurate projection of future primary TJA procedure demands is important in order to understand future health-care utilization and surgeon demand. This finding is only applicable to a Medicare population and demands further analysis to see if this extends to other population groups.Level of Evidence:Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND:Indications for surgery may impact resource utilization in aseptic revision total knee arthroplasty (rTKA), and understanding these relationships would facilitate risk-stratification preoperatively. The purpose of this study was to investigate the impact of rTKA indications on readmission, reoperation, length of stay (LOS), and cost. METHODS:We reviewed all 962 patients who underwent aseptic rTKA at an academic orthopedic specialty hospital between June 2011-April 2020 with at least 90 days of follow-up. Patients were categorized based on their indication for aseptic rTKA as listed in the operative report. Demographics, surgical factors, LOS, readmission, reoperation and cost were compared between cohorts. RESULTS:There were significant differences in operative time among cohorts (p < 0.001), highest among the periprosthetic fracture group (164.2 ± 59.8 min). Reoperation rate was greatest in the extensor mechanism disruption cohort (50.0 %, p = 0.009). Total cost differed significantly among groups (p < 0.001), which was highest among the implant failure cohort (134.6 % of mean) and lowest for component malpositioning cohort (90.2 % of mean). Similarly, there were significant differences in direct cost (p < 0.001) which was highest in the periprosthetic fracture cohort (138.5 % of mean), and lowest in the implant failure cohort (90.5 % of mean). There were no differences in discharge disposition, or number of re-revisions among all groups. CONCLUSIONS:Operative time, components revised, LOS, readmissions, reoperation rate, total cost and direct cost following aseptic rTKA varied significantly between different revision indications. These differences should be noted for preoperative planning, resource allocation, scheduling, and risk-stratification. LEVEL OF EVIDENCE/METHODS:III, retrospective observational analysis.

BACKGROUND:Some studies have shown lower morbidity and mortality rates with increased surgeon and hospital volumes after total hip arthroplasty (THA). This study sought to determine the relationship between surgeon and hospital volumes and patient-reported outcome measures after THA using American Joint Replacement Registry data. METHODS:Using American Joint Replacement Registry data from 2012 to 2020, 4,447 primary, elective THAs with both preoperative and 1-year postoperative Hip Dysfunction and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR) scores were analyzed. This study was powered to detect the minimum clinically important difference (MCID). The main exposure variables were median annual surgeon and hospital volumes. Tertiles were formed based on the median annual number of THAs conducted: low-volume (1 to 42), medium-volume (42 to 96), and high-volume (≥96) surgeons and low-volume (1 to 201), medium-volume (201 to 392), and high-volume (≥392) hospitals. Mean preoperative and 1-year postoperative HOOS-JR scores were compared. RESULTS:Preoperative HOOS-JR scores were significantly higher at high-volume hospitals than low-volume and medium-volume hospitals (49.66 ± 15.19 vs. 47.68 ± 15.09 and 48.34 ± 15.22, P < 0.001), although these differences were less than the MCID. At the 1-year follow-up, no difference was noted with no resultant MCID. Preoperative and 1-year HOOS-JR scores did not markedly vary with surgeon volume. In multivariate regression, low-volume and medium-volume surgeons and hospitals had similar odds of MCID achievement in HOOS-JR scores compared with high-volume surgeons and hospitals, respectively. CONCLUSION/CONCLUSIONS:Using the HOOS-JR score as a validated patient-reported outcome measure, higher surgeon or hospital THA volume did not correlate with higher postoperative HOOS-JR scores or greater chances of MCID achievement in HOOS-JR scores compared with medium and lower volume surgeons and hospitals.

Background: Current literature does not provide conclusive evidence on whether routine pathologic examination of femoral heads from total hip arthroplasty is indicated or cost-effective. As a result, there is substantial variation in opinion among surgeons related to this issue. Our study aim was to determine factors that impact surgeon propensity to order pathologic examination of femoral heads. Methods: A 12-question survey was created to evaluate surgeon practices, indications, and patient care implications surrounding routine pathologic examination of femoral heads. The email survey was distributed to all members of the American Association of Hip and Knee Surgeons (n = 2598). Results: There were 572 survey respondents. Out of all respondents, 28.4% always send femoral heads to pathology, and 27.6% reported an institutional requirement to do so. Of the 572 surgeons, 73.6% report femoral head pathology has never resulted in a change in patient disease course. Factors that increase the likelihood of surgeons ordering femoral head pathologic examination include institutional requirements, medicolegal concern, and prior experience with femoral head pathologic examination changing patients' disease course (P <.001). Cost concern decreases the likelihood of surgeons ordering femoral head pathologic examination (P =.0012). Conclusions: A minority of surgeons routinely send femoral heads from total hip arthroplasty for pathologic examination, mostly because of institutional requirement. The majority of surgeons feel that femoral head pathologic examination never changes patient management, although others have infrequently detected malignancy and infection. Institutional policy, concern for litigation, and prior experience with discordant pathologic diagnoses increase femoral head pathologic examinations, while cost concern decreases them.

Mucopolysaccharidosis encompasses multiple lysosomal storage disorders that are relevant to the orthopedic surgeon as they lead to disruption in bone and cartilage development. These patients may present with early-onset joint pain, including end-stage hip arthritis warranting total hip replacement. The altered hip anatomy in this disorder is of specific importance to the arthroplasty surgeon as it presents challenges when reconstructing the proximal femur and acetabulum and informs implant choice. We present a 17-year-old patient with end-stage bilateral hip arthritis who underwent staged bilateral total hip arthroplasty. We discuss technical considerations in surgical technique and the consequences of acetabular and femoral deformity on implant selection.

INTRODUCTION/BACKGROUND:Removal of primary total knee arthroplasty (TKA) and primary total hip arthroplasty (THA) from the inpatient-only (IPO) list has financial implications for both patients and institutions. The aim of this study was to evaluate and compare financial parameters between patients designated for inpatient versus outpatient total joint arthroplasty (TJA) surgery. METHODS:We reviewed all patients who underwent TKA or THA after these procedures were removed from the IPO list. Patients were stratified into cohorts based on inpatient or outpatient status, procedure type, and insurance type. This included 5,284 patients, of which 4,279 were designated inpatient while 1,005 were designated outpatient. Patient demographic, perioperative, and financial data including per patient revenues, total and direct costs, and contribution margins (CMs) were collected. Data were compared using t-tests and Chi-square tests. RESULTS:Among Medicare patients receiving THA, CM was 89.1% lower for the inpatient cohort when compared to outpatient (p<0.001), though there was no significant difference between cohorts for TKA (p=0.501). Among patients covered by Medicaid or Government-managed plans, CM was 120.8% higher for inpatients receiving THA (p<0.001) when compared to outpatients and 136.3% higher for inpatients receiving TKA (p<0.001). CONCLUSION/CONCLUSIONS:Our analyses showed that recent costs associated with inpatient stay inconsistently match or outpace additional revenue, causing CM to vary drastically depending on insurance and procedure type. For Medicare patients receiving THA, inpatient surgery is financially disincentivized leaving this vulnerable patient population at risk of losing access to care.

AIM/OBJECTIVE:Posterior stabilized (PS) and varus valgus constrained (VVC) knee polyethylene liners have been shown to confer excellent long-term functional results following revision total knee arthroplasty (rTKA). The purpose of this study was to compare outcomes of patients who underwent rTKA using either a PS or VVC liner. METHODS:A retrospective comparative study of 314 rTKA with either PS or VVC liner and a minimum follow-up time of two years was conducted. Patient demographics, complications, readmissions, and re-revision etiology and rates were compared between groups. Kaplan-Meier survivorship analysis was performed to estimate freedom from all-cause revision. RESULTS:Hospital LOS (3.41 ± 2.49 vs. 3.34 ± 1.93 days, p = 0.793) and discharge disposition (p = 0.418) did not significantly differ between groups. At a mean follow-up of 3.55 ± 1.60 years, the proportion of patients undergoing re-revision did not significantly differ (19.1% vs. 18.7%, p = 0.929). In subgroup analysis of re-revision causes, the VVC cohort had superior survival from re-revision due to instability compared to the PS cohort (97.8% vs. 89.4%, p = 0.003). Freedom from re-revision due to aseptic loosening did not significantly differ between groups (85.2% vs. 78.8%, p = 0.436). Improvements in range of motion (ROM) from preoperative to latest follow-up were similar as well. CONCLUSIONS:PS and VVC liners confer similar survivorship, complication rates, and overall knee ROM in rTKA. VVC liners were not associated with increased postoperative aseptic loosening and demonstrated superior freedom from re-revision due to instability. Future studies with longer follow-up are warranted to better determine significant differences in clinical outcomes between the two bearing options. LEVEL III EVIDENCE/METHODS:Retrospective Cohort Study.