Faculty Bibliography

Purpose: The study aimed to determine whether body mass index (BMI) classification for patients undergoing total knee arthroplasty (TKA) is associated with differences in mean patient reported outcome measure (PROM) score improvements across multiple domains"”including pain, functional status, mental health, and global physical health. We hypothesized that patients with larger BMIs would have worse preoperative and postoperative PROM scores, though improvements in scores would be comparable between groups. Materials and methods: Patients undergoing primary TKA from 2018 to 2021 were retrospectively reviewed and stratified into four groups: Normal Weight; 18.5"“25 kg/m², Overweight; 25.01"“30 kg/m², Obese; 30.01"“40 kg/m², and Morbidly Obese > 40 kg/m². Preoperative, postoperative, and pre/post-changes (Δ) in knee injury and osteoarthritis, joint replacement (KOOS, JR) and Patient-Reported Outcome Measurement Information System (PROMIS) measures of pain intensity, pain interference, physical function, mobility, mental health, and physical health were compared. Multivariate linear regression was used to assess for confounding comorbid conditions. Results: In univariate analysis, patients with larger BMIs had worse scores for KOOS, JR and all PROMIS metrics preoperatively. Postoperatively, scores for KOOS, JR and PROMIS pain interference, mobility, and physical health were statistically worse in higher BMI groups, though differences were not clinically significant. Morbidly obese patients achieved greater pre/post-Δ improvements in KOOS, JR and global physical health scores. Multivariate regression analysis showed high BMI was independently associated with greater pre/post-Δ improvements in KOOS, JR and global health scores. Conclusion: Obese patients report worse preoperative scores for function and health, but greater pre/post-Δ improvements in KOOS, JR and physical health scores following TKA. Quality of life benefits of TKA in obese patients should be a factor when assessing surgical candidacy.

INTRODUCTION/BACKGROUND:Infection after total knee arthroplasty (TKA) impacts the patient, surgeon, and healthcare system significantly. Surgeons routinely use antibiotic-loaded bone cement (ALBC) in attempts to mitigate infection; however, little evidence supports the efficacy of ALBC in reducing infection rates compared to non-antibiotic-loaded bone cement (non-ALBC) in primary TKA. Our study compares infection rates of patients undergoing TKA with ALBC to those with non-ALBC to assess its efficacy in primary TKA. METHODS:A retrospective review of all primary, elective, cemented TKA patients over the age of 18 between 2011 and 2020 was conducted at an orthopedic specialty hospital. Patients were stratified into two cohorts based on cement type: ALBC (loaded with gentamicin or tobramycin) or non-ALBC. Baseline characteristics and infection rates determined by MSIS criteria were collected. Multilinear and multivariate logistic regressions were performed to limit significant differences in demographics. Independent samples t test and chi-squared test were used to compare means and proportions, respectively, between the two cohorts. RESULTS:) and Charlson Comorbidity Index values (4.51 ± 2.15 vs. 4.04 ± 1.92) were more likely to receive ALBC. The infection rate in the non-ALBC was 0.8% (63/7,980), while the rate in the ALBC was 0.5% (7/1,386). After adjusting for confounders, the difference in rates was not significant between the two groups (OR [95% CI]: 1.53 [0.69-3.38], p = 0.298). Furthermore, a sub-analysis comparing the infection rates within various demographic categories also showed no significant differences between the two groups. CONCLUSION/CONCLUSIONS:Compared to non-ALBC, the overall infection rate in primary TKA was slightly lower when using ALBC; however, the difference was not statistically significant. When stratifying by comorbidity, use of ALBC still showed no statistical significance in reducing the risk of periprosthetic joint infection. Therefore, the advantage of antibiotics in bone cement to prevent infection in primary TKA is not yet elucidated. Further prospective, multicenter studies regarding the clinical benefits of antibiotic use in bone cement for primary TKA are warranted.

INTRODUCTION/BACKGROUND:Previous studies have demonstrated that patients with positive preoperative urine toxicology (utox) screens prior to total joint arthroplasty (TJA) have higher readmission rates, greater complication rates, and longer hospital stays compared to patients with negative screens. The aim of this study was to investigate the effect of postponing surgery for patients with positive preoperative utox in the Medicaid population. METHODS:This retrospective, observational study reviewed the Medicaid ambulatory database at a large, academic orthopedic specialty hospital for patients with a utox screen prior to TJA from 2012 to 2020. Patients were categorized into three groups: (1) controls with negative preoperative utox or a utox consistent with prescription medications (Utox-) with TJA completed as scheduled; (2) positive preoperative utox with TJA rescheduled and surgery completed on a later date (R-utox+); (3) positive preoperative utox inconsistent with prescription medications with TJA completed as scheduled (S-utox+). Primary outcomes included mortality, 90-day readmission rate, complication rate, and length of stay. RESULTS:Of the 300 records reviewed, 185 did not meet inclusion criteria. The remaining 115 patients included 80 (69.6%) Utox-, 5 (6.3%) R-utox+, and 30 (37.5%) S-utox+. Mean follow-up time was 49.6 months. Hospital stays trended longer in the Utox- group (3.7 ± 2.0 days vs. 3.1 ± 1.6 S-utox+ vs.2.5 ± 0.4 R-utox+, p = 0.20). Compared to the R-utox+group, the S-utox+ group trended toward lower home discharge rates (p = 0.20), higher in-hospital complication rates (p = 0.85), and more all-cause 90-day emergency department visits (p = 0.57). There were no differences in postoperative opioid utilization between groups (p = 0.319). Duration of postoperative narcotic use trended toward being longer in the Utox- patients (820.7 ± 1073.8 days vs. 684.6 ± 1491.8 S-utox+ vs. 585.1 ± 948.3 R-utox+, p = 0.585). Surgical time (p = 0.045) and revision rates (p = 0.72) trended toward being higher in the S-utox+ group. CONCLUSIONS:Medicaid patients with positive preoperative utox who had surgeries postponed trended towards shorter hospital stays and greater home discharge rates. Larger studies should be conducted to analyze the implications of a positive preoperative utox on risk profiles and outcomes following TJA in the Medicaid population. Study design Retrospective cohort study.

PURPOSE/OBJECTIVE:The purpose of the current study was to determine if differences exist between cruciate-retaining (CR) and posterior-stabilized (PS) implant articulations for total knee arthroplasty (TKA) with regards to early post-operative pain. METHODS:We retrospectively reviewed patients who underwent primary TKA, with the same TKA implant design, at our institution between January 2018 and July 2021. Patients were stratified based on whether they received a CR or non-constrained PS (PSnC) articulation and propensity score matched in a 1:1 ratio. A sub-analysis matching patient who received a constrained PS implant (PSC) to those undergoing CR TKA and PSnC TKA was also carried out. Opioid dosages were converted to morphine milligram equivalents (MME). RESULTS:616 patients after CR TKA were matched 1:1 to 616 patients with a PSnC implant. There were no significant differences between demographic variables. There were no statistically significant differences in opioid usage measured by MME on post-operative day (POD) 0 (p = 0.171), POD1 (p = 0.839), POD2 (p = 0.307), or POD3 (p = 0.138); VAS pain scores (p = 0.175); or 90-day readmission rate for pain (p = 0.654). A sub-analysis of CR versus PSC TKA demonstrated no significant differences in opioid usage on POD0 (p = 0.765), POD1 (p = 0.747), POD2 (p = 0.564), POD3 (p = 0.309); VAS pain scores (p = 0.293); and 90-day readmission rate for pain (p > 0.9). CONCLUSION/CONCLUSIONS:Our analysis demonstrated no significant difference in post-operative VAS pain scores and MME usage based on implant. The results suggest that neither the type of articulation or constraint used for primary TKA has a significant impact on immediate post-operative pain and opioid consumption. LEVEL III EVIDENCE/METHODS:Retrospective Cohort Study.

INTRODUCTION/BACKGROUND:Malnutrition is associated with poorer outcomes after revision total joint arthroplasty (rTJA), though no universal metric for assessing malnutrition in rTJA patients has been reported. This study sought to determine if malnutrition as defined by the Geriatric Nutritional Risk Index (GNRI) can independently predict short-term complication rates and re-revision risk in patients undergoing rTJA. METHODS:All patients ≥ 65 years old undergoing rTJA from 2011 to 2021 at a single orthopaedic specialty hospital were identified. Preoperative albumin, height, and weight were used to calculate GNRI. Based on the calculated GNRI value, patients were stratified into three groups: normal nutrition (GNRI > 98), moderate malnutrition (GNRI 92-98), and severe malnutrition (GNRI < 92). Chi-squared and independent samples t-tests were used to compare groups. RESULTS:A total of 531 rTJA patients were included. Patients with normal nutrition were younger (p < 0.001), had higher BMI (p < 0.001). After adjusting for baseline characteristics, patients with severe and moderate malnutrition had longer length of stay (p < 0.001), were less likely to be discharged home (p = 0.049), and had higher 90-day major complication (p = 0.02) and readmission (p = 0.005) rates than those with normal nutrition. 90-day revision rates were similar. In Kaplan-Meier analyses, patients with severe and moderate malnutrition had worse survivorship free of all-cause re-revision at 1-year (p = 0.001) and 2-year (p = 0.002) follow-up compared to those with normal nutrition. CONCLUSION/CONCLUSIONS:Moderate and severe malnutrition, as defined by GNRI, independently predicted higher complication and revision rates in rTJA patients. This suggests that the GNRI may serve as an effective screening tool for nutritional status in patients undergoing rTJA.

BACKGROUND:Periprosthetic joint infection (PJI) and subsequent revision surgeries may affect patients' social and physical health, ability to complete daily activities, and disability status. This study sought to determine how PJI affects patients' quality of life through patient-reported outcome measures with minimum 1-year follow-up. METHODS:Patients who suffered PJI following primary total joint arthroplasty (TJA) from 2012 to 2021 were retrospectively reviewed. Patients met Musculoskeletal Infection Society criteria for acute or chronic PJI, underwent revision TJA surgery, and had at least 1 year of follow-up. Patients were surveyed regarding how PJI affected their work and disability status, as well as their mental and physical health. Outcome measures were compared between acute and chronic PJIs. In total, 318 patients (48.4% total knee arthroplasty and 51.6% total hip arthroplasty) met inclusion criteria. RESULTS:Following surgical treatment for knee and hip PJI, a substantial proportion of patients reported that they were unable to negotiate stairs (20.5%), had worse physical health (39.6%), and suffered worse mental health (25.2%). A high proportion of patients reported worse quality of life (38.5%) and social satisfaction (35.3%) following PJI. Worse reported patient-reported outcome measures including patients' ability to complete daily physical activities were found among patients undergoing treatment for chronic PJI, and also, 23% of patients regretted their initial decision to pursue primary TJA. CONCLUSIONS:A PJI negatively affects patients' ability to carry out everyday activities. This patient population is prone to report challenges overcoming disability and returning to work. Patients should be adequately educated regarding the risk of PJI to decrease later potential regrets. LEVEL OF EVIDENCE/METHODS:Case series (IV).

Background:The use of a cemented monoblock dual-mobility implant into a fully porous cup is indicated for patients with acetabular bone loss who have a high risk of postoperative hip instability. Patients undergoing lumbar fusion for sagittal spinal deformities have an increased risk of hip dislocation (7.1%) and should be assessed on sitting and standing radiographs¹. Gabor et al. conducted a multicenter, retrospective study assessing the use of a cemented monoblock dual-mobility bearing in a porous acetabular shell in patients with acetabular bone loss and a high risk of hip instability². Of the 38 patients, 1 (2.6%) experienced a postoperative dislocation that was subsequently treated with closed reduction without further dislocation. This surgical technique represents a favorable surgical option for patients with acetabular bone loss who are at risk for hip instability. In the example case described in the present video article, the patients had a history of dislocations, lumbar fusion, and evidence of Paprosky 3B acetabular defect; as such, the decision was made to revise to a porous shell and cement a monoblock dual-mobility implant.Description:With use of the surgeon's preferred approach, the soft tissue is dissected and the hip is aspirated. The hip is dislocated and a subgluteal pocket is made with use of electrocautery to mobilize the trunnion of the femoral stem to aid in acetabular exposure. The femoral component is assessed to ensure appropriate positioning with adequate anteversion. The acetabular component and any acetabular screws are removed. A "ream to fit" technique is performed in the acetabulum until bleeding bone is encountered, with minimal reaming performed in healthy bone from the posterior column. A trial prosthesis is placed within the acetabulum to evaluate if there is satisfactory fixation and if any augment is necessary. Care must be taken during reaming to ensure that enough bone is reamed to accommodate a porous shell that can fit the monoblock dual-mobility implant with a 2-mm cement mantle. Smaller porous shells measuring 56 mm are available for smaller defects but are often not utilized in cases of substantial acetabular bone loss. Fresh-frozen cancellous allograft is utilized to fill any contained defects. The revision porous shell with circumferential screw holes is utilized to allow for screw fixation posterosuperior and anterior toward the pubis. The implants are dried prior to placement of the cement. The cement is applied to the shell and the monoblock dual-mobility implant to ensure adequate coverage. Antibiotic-loaded cement can be utilized according to surgeon preference. Excess cement is removed under direct visualization while the cement is drying, and the position of the dual-mobility implant is adjusted in approximately 20° anteversion and 40° inclination. Stability is assessed after the cement cures, and intraoperative radiography can be performed to confirm cup positioning prior to closure. Any remaining capsule is closed, followed by closure of the remaining soft tissue in a layered fashion.Alternatives:A fully porous multi-hole jumbo cup with conventional polyethylene liner and femoral head can be utilized to increase the jump distance of the femoral head. Constrained, lipped, or offset polyethylene liners can be utilized if the shell is well fixed and a dual-mobility implant cannot be inserted. A cemented dual-mobility implant can be utilized in a well-fixed acetabular shell without evidence of loosening or osteolysis.Rationale:Dual-mobility implants have become increasingly utilized because of their advantages: (1) ability to decrease dislocation rate without increasing constraint and (2) increasing range of motion with reduced impingement risk^2-8. These implants are particularly useful in the setting of revision cases with large acetabular bone defects. In a study of 76 patients with dual-mobility implants cemented into porous acetabular shells, Muthusamy et al. found that only 3.3% of patients experienced postoperative dislocations⁹. Moreover, acetabular cup survival was excellent, with 100% survival at 1 year and 96.2% at 2 years.Expected Outcomes:The use of a dual-mobility implant is a viable treatment option in cases of revision total hip arthroplasty, particularly those in which postoperative stability is a concern; monoblock dual-mobility implants cemented into porous shells are particularly useful in this setting^2-8. These trends are similarly seen in patients treated with monoblock dual-mobility implants cemented into porous shells. Muthusamy et al. evaluated the use of this construct to treat instability or risk of hip dislocation in 76 hips, reporting a dislocation rate of 3.3% at 2 years. Additionally, the authors reported rates of all-cause acetabular survival from re-revision of 96.7% at 6 months, 93.3% at 1 year, and 89.7% at 2 years⁹. Physicians should be aware of the possibility for intra-prosthetic dislocations, as although this complication is rare, it has been reported in the literature^7,10.Important Tips:In order to allow for circumferential coverage for fixation and ingrowth potential in cases with acetabular defects, the shell is typically impacted slightly vertical (45° to 50° of inclination) and in neutral version (0° to 5° of anteversion). Positioning can be adjusted to improve osseous contact and ingrowth as determined by the size and shape of the defect.The use of a drill guide for the locking screws allows limited degrees of variable screw angulation. In the revision setting, longer screws may be placed posterosuperior toward the sciatic notch or anteroinferior into the pubis. Surgeons should be aware of the anatomy and should predrill holes to reduce the risk of injury to surrounding neurovascular structures such as the obturator artery anteriorly.Any screw holes that are not filled should be covered with plastic hole covers in order to prevent cement from migrating behind the cup. Implants should be dried prior to the placement of the cement, and the cement should be applied to the shell and the dual-mobility implant to ensure adequate coverage.Utilize a monoblock dual-mobility implant that is designed for cementation in order to avoid implant dissociation from the acetabular shell.Remove all fibrous tissue that may hinder bony integration.Assess for pelvis discontinuity; pelvis discontinuity and acetabular bone loss are risk factors in the setting of any revision and should be properly assessed preoperatively and intraoperatively and managed accordingly.Avoid over-reaming and damage of the posterior column.Utilize a reamer or trial to assess defect size and need for augments.Place a compression screw where the cup is in contact with the bone in order to avoid tilting.Cover unused screw holes.Acronyms and Abbreviations:THA = total hip arthroplastyS/P = status postTKA = total knee arthroplastyCT = computed tomographyKM = Kaplan MeierDMC = dual-mobility cupPE = polyethylene.

Introduction: Bone loss is present in all revision total knee arthroplasties. Metaphyseal cones allow surgeons to negotiate 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 revision total knee arthroplasty (rTKA) utilizing a novel metaphyseal cone system. Methods: This multicenter retrospective study examined all patients who received a porous, titanium tibial or femoral cone at four academic urban tertiary care institutions and presented for a minimum two-year follow-up. Patient demographics, indications for revision surgery, knee range-of-motion (ROM), re-revision rates, radiographic measurements, bone defect per AORI classification, and implant osseointegration were evaluated according to the Knee Society total knee arthroplasty (TKA) radiographic evaluation system. Results: One-hundred and four patients received 128 cone implants (84 tibial, 44 femoral cones; 24 patients with simultaneous ipsilateral tibial and femoral cones; 104 rTKA) with mean follow-up of 32.75 ± 6.54 months. The pre-operative main revision indications were aseptic loosening 36 (34.61 %), periprosthetic infection (PJI) 23 (22.11 %) and instability 18 (17.3 %). Thirteen rTKA underwent re-revision surgery: 3 for acute PJI, 4 for chronic PJI, 5 for instability, and 1 for mechanical failure of a hinged system. At most recent radiographic follow-up available, all unrevised cones had evidence of osteointegration and no visible implant migration. All-cause re-operation free survivorship was 87.5 % (91/104), and all-cause cone implant survivorship was 96.09 % (123/128 cones) at 2-year follow-up. Conclusion: This study demonstrates excellent mid-term outcomes of a novel porous, titanium metaphyseal cone in patients with large bone defects undergoing complex revision TKA. Level of evidence: IV, case series.

INTRODUCTION/BACKGROUND:Comparison between fully hydroxyapatite (HA)-coated stems with differing geometry are lacking in the total hip arthroplasty (THA) literature. This study aimed to compare femoral canal fill, radiolucency formation, and 2-year implant survivorship between two commonly used, HA-coated stems. METHODS:All primary THAs performed with two fully HA-coated stems (Polar stem, Smith&Nephew, Memphis, TN and Corail stem, DePuy-Synthes, Warsaw, IN) with a minimum 2-year radiographic follow-up were identified. Radiographic measures of proximal femoral morphology based on the Dorr classification and femoral canal fill were analyzed. Radiolucent lines were identified by Gruen zone. Perioperative characteristics and 2-year survivorship were compared between stem types. RESULTS:A total of 233 patients were identified with 132 (56.7%) receiving the Polar stem (P) and 101 (43.3%) receiving the Corail stem (C). No differences were observed with respect to proximal femoral morphology. Femoral stem canal fill at the middle third of the stem was greater for P stem patients than for C stem patients (P stem; 0.80 ± 0.08 vs. C stem; 0.77 ± 0.08, p = 0.002), while femoral stem canal fill at the distal third of the stem and presence of subsidence were comparable between groups. A total of six and nine radiolucencies were observed in P stem and C stem patients, respectively. Revision rate at 2-year (P stem; 1.5% vs C stem; 0.0%, p = 0.51) and latest follow-up (P stem; 1.5% vs C stem; 1.0%, p = 0.72) did not differ between groups. CONCLUSION/CONCLUSIONS:Greater canal fill at the middle third of the stem was observed for the P stem compared to the C stem, however, both stems demonstrated robust and comparable freedom from revision at 2-year and latest follow-up, with low incidences of radiolucent line formation. Mid-term clinical and radiographic outcomes for these commonly used, fully HA-coated stems remain equally promising in THA despite variations in canal fill.

INTRODUCTION/BACKGROUND:To improve revision total hip arthroplasty (rTHA) prognosis and postoperative management, a better understanding of how non-elective and elective indications influence clinical outcomes is needed. We sought to compare ambulatory status, complication rates, and implant survival rates in patients who underwent aseptic rTHA for periprosthetic fracture or elective indications. MATERIALS AND METHODS/METHODS:This retrospective study examined all aseptic rTHA patients with a minimum follow-up of two years at a single tertiary referral center. Patients were divided into two groups: fracture rTHA (F-rTHA) if the patient had a periprosthetic femoral or acetabular fracture, and elective rTHA (E-rTHA) if the patient underwent rTHA for other aseptic indications. Multivariate regression was performed for clinical outcomes to adjust for baseline characteristics, and Kaplan-Meier analysis was performed to assess implant survival. RESULTS:A total of 324 patients (F-rTHA: 67, E-rTHA: 257) were included. In the F-rTHA cohort, 57 (85.0%) and 10 (15.0%) had femoral and acetabular periprosthetic fractures, respectively. F-rTHA patients were more likely to be discharged to skilled nursing (40.3% vs. 22.2%, p = 0.049) and acute rehabilitation facilities (19.4% vs. 7.8%, p = 0.004). F-rTHA patients had higher 90-day readmission rates (26.9% vs. 16.0%, p = 0.033). Ambulatory status at three months postoperatively significantly differed (p = 0.004); F-rTHA patients were more likely to use a walker (44.6% vs. 18.8%) and less likely to ambulate independently (19.6% vs. 28.6%) or with a cane (28.6% vs. 41.1%). These differences did not persist at one and two years postoperatively. Freedom from all-cause re-revision (77.6% vs. 74.7%, p = 0.912) and re-revision due to PJI (88.1% vs. 91.9%, p = 0.206) were similar at five-year follow-up. CONCLUSIONS:Compared to rTHA performed for elective aseptic indications, fracture rTHA patients had poorer early functional outcomes, with greater need for ambulatory aids and non-home discharge. However, these differences did not persist long term and did not portend increased infection or re-revision rates.