The Surgical Approach Impacts Component Selection in Total Hip Arthroplasty: A Matched Cohort Study of 7,460 Hips.

BACKGROUND: A higher risk of dislocation following total hip arthroplasty (THA) has been reported for the posterior approach (PA) compared to the anterior approach (AA). Dual mobility implants, larger head sizes, and elevated or face-changing liners can reduce the risk for dislocation. It remains unclear whether the component selection is influenced by the surgical approach. METHODS: This is a retrospective study of 7,048 patients who underwent 7,460 primary THA with either AA or PA for primary hip osteoarthritis or osteonecrosis of the femoral head between 2019 and 2021. A propensity score model based on age, body mass index, height, and American Association of Anesthesiologists Score was applied. There were 2,502 AA-THA matched with 4,958 PA-THA (2,456 1:2, and 46 1:1). Groups were compared with multiple linear regression analyses/multivariate logistic regressions after controlling for American Association of Anesthesiologists Score and body mass index. In a second step, only hips operated by surgeons using both approaches were matched 1:1 (1,204 PA and AA, respectively). The same statistics were performed after controlling for "surgeon". RESULTS: The PA was associated with a more frequent use of dual mobility implants, elevated liners, face-changing liners, as well as heads with 36 mm or larger diameters, and the implanted cups were significantly larger (P < .001, respectively). These findings were consistent for both matched cohorts. CONCLUSION: The surgical approach impacts the component selection in THA. Patients undergoing PA-THA are more likely to receive implants with larger head size or stabilizing features compared to AA-THA.

Does Computer Navigation or Robotic Assistance Affect the Risk of Periprosthetic Joint Infection in Primary Total Knee Arthroplasty? A Propensity Score-Matched Cohort Analysis.

BACKGROUND: The use of technology during total knee arthroplasty (TKA) has been associated with more accurate component position and less blood loss. Yet to date, the risk of developing prosthetic joint infection (PJI) associated with computer navigation (CN) or robotic assistance (RA) has not been thoroughly evaluated. This study used propensity score-matching (PSM) in a large cohort of primary TKA patients to compare the rate of PJI following conventional TKA (TKA) versus CN-TKA and RA-TKA. METHODS: We retrospectively reviewed 13,015 knees in 11,727 patients who underwent primary TKA at a single institution from 2018 to 2021. The cohort was stratified into TKA, CN-TKA, and RA-TKA groups. 1:1 PSM was applied to 11,834 patients. Propensity score-matching was performed using logistic regression accounting for age, sex, body mass index, Charlson Comorbidity Index (CCI) score, CCI components, and smoking status. Univariate and multivariable analyses were performed to evaluate differences in surgical time and PJI rate. RESULTS: Significantly longer median operating times were noted in the RA-TKA group (14 minutes) compared to TKA (P < .001). The PJI rates among matched cohorts were similar among RA-TKA (0.3%), CN-TKA (0.3%), and conventional TKA (0.5%). Multivariable logistic regressions demonstrated that the use of robotic assistance (odds ratio (OR) = 0.5, P = .423) or computer navigation (OR = 0.61, P = .128) was not associated with increased risk of PJI when compared to conventional TKA. CONCLUSIONS: Use of computer navigation and robotic assistance during primary TKA are associated with longer surgical times, but no difference in PJI frequency within 90 days of surgery.

Clinical Outcomes of Isolated Polyethylene Exchange Versus Full Component Revision for the Management of Instability Following Total Knee Arthroplasty.

BACKGROUND: Instability following total knee arthroplasty (TKA) is a common cause for revision. Isolated polyethylene exchange (IPE) can be performed to increase knee joint stability, but results have been mixed. The purpose of this study was to compare the survivorship and patient-reported outcomes of patients undergoing revision TKA for instability with IPE versus full component revision. METHODS: We reviewed 280 primary TKAs undergoing revision TKA for instability. There were 181 knees that underwent revision with IPE, compared to 99 knees treated with full component revision. The mean follow-up was 32.8 months (range, 24.8 to 82.5). Patient demographics, radiographic parameters, prosthesis constraints, reoperations for instability, and patient-reported outcomes were compared. RESULTS: The survivorship for instability was significantly higher at 2 years (99 versus 92%, P = .024) and 5 years (94 versus 84%, P = .024) for patients undergoing full component revision. Although there was no difference in Knee Injury and Osteoarthritis Outcome Score for Joint Replacements and Veterans RAND 12 physical component scores between the 2 groups at 6 weeks, 1 year, and 2 years after surgery, full revision patients reported greater pain relief (P = .006) and greater improvements in Veterans RAND 12 physical component scores (P = .027) at 1 year and Knee Injury and Osteoarthritis Outcome Score for Joint Replacements scores at 2 years (P = .017) compared to IPE patients. Men were associated with an increased risk for recurrent instability following IPE (hazard ratio 3.3, 95% confidence interval: [1.0 to 10.6]). CONCLUSIONS: Isolated polyethylene exchange was not as reliable or durable compared to full component revision for the management of postoperative instability. These procedures should only be reserved in cases with competent collaterals and when component position, offset, and rotation are optimized.

Should We Wait for Bone-on-Bone Arthritis? Equivalent Clinical Outcomes in Patients Requiring Advanced Imaging Before Primary Total Hip Arthroplasty.

BACKGROUND: Plain radiographs remain the standard for diagnosing osteoarthritis (OA). Total hip arthroplasty (THA) is generally offered only for advanced OA by plain radiographs. Advanced imaging is used as an adjunct to assess OA severity in cases of progressive symptoms with less advanced OA by plain radiographs. The objective of this study was to compare outcomes following THA in patients who have advanced OA visualized by plain radiographs to patients who have less severe OA visualized by plain radiographs. METHODS: From February 2016 to February 2020, 93 patients who had Kellgren-Lawrence (KL) grade 0 to 2 OA and underwent THA were identified. The median age was 65 years, and 55% were women. They were matched 1:3 to patients who underwent THA for KL 4 OA based on age, sex, body mass index, and Charlson Comorbidity Index. The primary outcome was achievement of the Hip Injury and Osteoarthritis Outcome Score for Joint Replacement (HOOS JR) minimum clinically important difference, substantial clinical benefit, and patient-acceptable symptom state at 1 year postoperatively. RESULTS: There was no difference between the KL 0 to 2 and KL 4 cohorts in the achievement of HOOS JR minimum clinically important difference (86 versus 85.6%, P = .922), substantial clinical benefit (81.7 versus 80.2%, P = .751), or patient-acceptable symptom state (89.2 versus 85.6%, P = .374). The KL 0 to 2 cohort had a similar improvement in their 2-year HOOS JR (42.5 versus 38.6, P = .019). CONCLUSIONS: In this series, there was no difference in outcomes following primary THA between patients who have severe OA on plain radiographs (KL 4) compared to those who have less severe OA (KL 0 to 2). In the setting of severe symptoms and the absence of advanced OA on radiographs, advanced imaging can be used to guide treatment and select patients who could benefit from THA.

Contemporary Isolated Bearing Exchange for the Management of Hip Instability Following Primary Total Hip Arthroplasty.

BACKGROUND: Isolated ball and liner exchanges (IBLEs) can be performed to increase hip joint stability, but historical results have been mixed due to a lack of head size options or dual mobility articulations. The purpose of this study was to evaluate the contemporary results of IBLEs in patients who have instability following primary total hip arthroplasty (THA). METHODS: We retrospectively reviewed 65 primary THAs from 2016 to 2020 with hip instability undergoing IBLE or conversion to dual mobility articulation. There were 31 men and 34 women who had an average age of 70 years (range, 26 to 92). The mean time to revision from primary was 40.1 months (range, 1 to 120). In 52 cases, IBLE was performed using conventional bearings, while 13 hips were converted to dual mobility. Radiographic factors, including acetabular component orientation, reproduction of hip joint offset, leg lengths, and outcomes such as recurrent instability requiring subsequent revision and patient-reported outcome measure, were recorded and compared. RESULTS: There were 12 (18.4%) hips that experienced subsequent instability and required another revision (17.3% ball and liner exchange versus 23.1% dual mobility articulation, P = .615). The mean time to rerevision for instability was 17.1 months. There were no significant differences in either acetabular component anteversion (P = .25) or restoration of hip joint offset (P = .87) in patients who required another revision for instability compared to those who did not, respectively. At 1 year, patients undergoing conventional bearing exchange reported higher Hip Dysfunction Osteoarthritis Outcome Score for Joint Replacements (P = .002) and Veterans Rand physical component (P = .023) scores compared to those who underwent a conversion to dual mobility articulation. Only age > 75 years at the time of surgery was associated with increased risk for dislocation (odds ratio 7.2, confidence interval 1.2 to 43.7, P = .032). CONCLUSIONS: Isolated bearing exchanges for instability following THA remained at high risk for subsequent instability. Conversion to dual mobility articulations did not reduce the risk of reoperation.

To Stage or Not to Stage? Comparison of Patient-Reported Outcomes, Complications, and Discharge Disposition After Staged and Simultaneous Bilateral Posterior Total Hip Arthroplasty.

BACKGROUND: Patients who have bilateral hip arthritis can be treated with bilateral total hip arthroplasty (bTHA) in either a staged or simultaneous fashion. The goal of this study was to determine whether staged and simultaneous posterior bTHA patients differ in regard to (1) patient-reported outcome measures, (2) 90-day complication rates, and (3) discharge dispositions and cumulative lengths of stay. METHODS: Patients who (1) underwent simultaneous bTHA or staged bTHA (within 12 months) using the posterior approach, and (2) completed preoperative and 1-year postoperative Hip dysfunction and Osteoarthritis Outcome Score for Joint Replacement surveys were included in the study. A total of 266 patients (87 simultaneous bTHA and 179 staged bTHA) were included. Chart review was performed to collect patient-level variables, postoperative complications, discharge dispositions, and lengths of stay. RESULTS: Staged bTHA patients had higher Hip dysfunction and Osteoarthritis Outcome Score for Joint Replacement, Lower Extremity Activity Scale, and Veterans RAND 12-Item Health Survey physical component scores compared to simultaneous bTHA patients at 6 weeks after surgery (P = .019, .006, and .008, respectively), but these differences did not meet the minimal clinically important difference threshold for any questionnaire. Simultaneous bTHA was associated with higher rate of periprosthetic fractures (P = .034) and discharge to a location other than home (P < .001). CONCLUSIONS: There were statistically significant, but likely not clinically meaningful differences in patient-reported outcomes for staged and simultaneous bTHA patients at 6 weeks after surgery. Surgeons should be aware of the higher periprosthetic fracture risk and greater likelihood of discharge to a rehabilitation facility associated with simultaneous bTHA. Further research should aim to understand which patients may benefit most from simultaneous bTHA.

Obesity Severity Does Not Associate With Rate, Timing, or Invasiveness of Early Reinterventions After Total Knee Arthroplasty.

BACKGROUND: The use of body mass index (BMI) cutoff values has been suggested for proceeding with total knee arthroplasty (TKA) in obese patients. However, the relationship between obesity severity and early reoperations after TKA is poorly defined. This study evaluated whether increased World Health Organization (WHO) obesity class was associated with risk, severity, and timing of reintervention within one year after TKA. METHODS: There were 8,674 patients from our institution who had a BMI ≥ 30 and underwent unilateral TKA for primary osteoarthritis between 2016 and 2021. Patients were grouped by WHO obesity class: 4,456 class I (51.5%), 2,527 class II (29.2%), and 1,677 class III (19.4%). A chart review was performed to determine patient characteristics and identify patients who underwent any closed or open reintervention requiring anesthesia within the first postoperative year. Regression analyses were performed to identify variables associated with increased odds ratios (ORs) for requiring a reintervention, its timing, and invasiveness. RESULTS: There were 158 patients (1.8%) who required at least one reintervention, and 15 patients (0.2%) required at least 2 reinterventions. Reintervention rates for obesity classes I, II, and III were 1.8% (n = 81), 2.0% (n = 51), and 1.4% (n = 23), respectively. There were 65 closed procedures (41.1%), 47 minor procedures (29.7%), 34 open with or without liner exchange (21.5%), and 12 revisions with component exchange (7.6%). Obesity class was not associated with reintervention rate (P = .3), timing (P = .36), or invasiveness (P = .93). Diabetes (odds ratio [OR] = 2.47; P = .008) was associated with a need for reintervention. Non-Caucasian race (OR = 1.7; P = .01) and Charlson comorbidity index (OR = 2.1; P = .008) were associated with earlier reintervention. No factors were associated with the invasiveness of reintervention. CONCLUSIONS: The WHO obesity class did not associate with rate, timing, or invasiveness of reintervention after TKA in obese patients. These findings suggest that policies that restrict the indication for elective TKA based only on a BMI limit have limited efficacy in reducing early reintervention after TKA in obese patients. LEVEL OF EVIDENCE: III.

Is Preoperative Weight Reduction in Patients Who Have Body Mass Index ≥ 40 Associated With Lower Complication Rates After Primary Total Hip Arthroplasty?

BACKGROUND: Given the heightened risk of postoperative complications associated with obesity, delaying total hip arthroplasty (THA) in patients who have a body mass index (BMI) > 40 to maximize preoperative weight loss has been advocated by professional societies and orthopaedic surgeons. While the benefits of this strategy are not well-understood, previous studies have suggested that a 5% reduction in weight or BMI may be associated with reduced complications after THA. METHODS: We identified 613 patients who underwent primary THA in a single institution during a 7-year period and who had a BMI >40 recorded from 9 to 12 months prior to surgery. Subjects were stratified into 3 cohorts based on whether their baseline BMI decreased by >5% (147 patients, 24%), was unchanged ( ± 5%) (336 patients, 55%), or increased by >5% (130 patients, 21%) on the day of surgery. The frequency of 90-days Hip Society and Centers for Medicare & Medicaid Services complications was compared between these cohorts. There were significant baseline differences between the cohorts with respect to baseline American Society of Anesthesiologists class (P < .001) and hemoglobin A1C (P = .011), which were accounted for in a multivariate regression analysis. RESULTS: In univariate analysis, there was a lower incidence of readmission (P = .025) and total complications (P = .005) in the increased BMI cohort. The overall complication rate was 18.4% in the decreased BMI cohort, 17.6% in the unchanged cohort, and 6.2% in the increased cohort. However, multivariable regression analysis controlling for potential confounders did not find that preoperative change in BMI was associated with differences in 90-days complications between cohorts (P > .05). CONCLUSIONS: Patients who have a BMI >40 and achieved a clinically significant (>5%) BMI reduction prior to THA did not have a lower risk of 90-days complications or readmissions. Thus, delaying THA in these patients to encourage weight loss may result in restricting access to a beneficial surgery without an appreciable safety benefit.

Femoral Component Debonding Frequently Missed on Advanced Imaging Prior to Revision of a Recalled Total Knee Arthroplasty.

BACKGROUND: Identification of femoral component debonding in the work-up of painful total knee arthroplasty (TKA) often poses a diagnostic challenge. The purpose of this study was to compare the sensitivity and specificity of radiographs, computed tomography (CT), and magnetic resonance imaging (MRI) for identifying femoral component loosening with debonding at the time of revision of a primary TKA with a recalled polyethylene insert. METHODS: Using an institutional database, we identified all cases of revision TKA performed for this specific implant recall following a primary TKA between 2014 and 2022. Patients who had a preoperative radiograph, CT, and MRI were included (n = 77). Sensitivity, specificity, and positive and negative likelihood ratio (LR) for predicting loosening were compared among the imaging modalities, using the intraoperative evidence of implant loosening as the gold standard. RESULTS: At the time of revision surgery, the femoral component was noted to have aseptic loosening with debonding in 46 of the 77 (60%) of the TKAs. There were no significant differences in demographics in the cohort with femoral debonding compared to those with well-fixed implants. The CT demonstrated a sensitivity of 28% and a specificity of 97%, while the MRI demonstrated a sensitivity of 37% and a specificity of 94% for detecting femoral loosening due to debonding. Both CT and MRI demonstrated poor negative LRs for femoral loosening (LR 0.7). CONCLUSIONS: In this series of revision TKAs for a specific recalled component, neither CT nor MRI accurately diagnosed femoral component debonding. For patients who have this implant, it is imperative to interrogate the implant-cement interface intraoperatively and prepare for full revision surgery as well as marked bone loss secondary to osteolysis.

Substantial Weight Loss May Not Improve Early Outcomes of Total Knee Arthroplasty in the Morbidly Obese.

BACKGROUND: Body mass index (BMI) cutoffs for morbidly obese patients otherwise indicated for total knee arthroplasty (TKA) have been widely proposed and implemented, though they remain controversial. Previous studies suggested that a 5% reduction in BMI may be associated with fewer postoperative complications. Thus, the purpose of this study was to determine whether a substantial reduction in preoperative BMI in morbidly obese patients improved 90-day outcomes after TKA. METHODS: There were 1,270 patients who underwent primary TKA at a single institution and had a BMI > 40 recorded during the year prior to surgery. Patients were stratified into three cohorts based on whether their BMI within 3 months to 1 year preoperatively had decreased by ≥ 5% (228 patients [18%]); increased by ≥ 5% (310 [24%]); or remained unchanged (within 5%) (732 [58%]) on the day of surgery. There were several baseline differences between the cohorts with respect to medical comorbidities. The rate of 90-day complications and six-week patient-reported outcome measures were compared via univariate and multivariable analyses. RESULTS: On univariate analysis, individual and total complication rates were similar between the cohorts (P > .05). On multivariable logistic regression, the risk of complications was similar in patients who had decreased versus unchanged BMI (OR [odds ratio] 1.0; P = .898). However, there was a higher risk of complications in the increased BMI cohort compared to those patients who had an unchanged BMI (OR 1.5; P = .039). The six-week patient-reported outcome measures were similar between the cohorts. CONCLUSIONS: Patients who have a BMI > 40 who achieved a meaningful reduction in BMI prior to TKA did not have a lower rate of 90-day complications than those whose BMI remained unchanged. Furthermore, considering that nearly one in four patients experienced a significant increase in BMI while awaiting surgery, postponing TKA may actually be detrimental.

Characterizing the Magnitude and Risk Factors of Functional and Anatomic Limb Lengthening in Patients Undergoing Revision Total Knee Arthroplasty.

BACKGROUND: In revision total knee arthroplasty (TKA), there is little information on the magnitude of potential limb lengthening, risk factors for lengthening, or its impact on patient-reported outcome measures. We aimed to quantify limb length alteration during revision TKA and assess risk factors for lengthening. METHODS: We identified 150 patients over a 3-year period who underwent revision TKA and had preoperative and postoperative EOS hip-to-ankle standing radiographs. The average patient age was 64 years, 51% were women; 68% had a preoperative varus deformity and 21% had a preoperative valgus deformity. Outcomes assessed included change in functional and anatomic limb length, risk factors for lengthening, and clinical outcome scores, including the Knee Osteoarthritis Outcome Score Joint Replacement, and the Veterans RAND 12-item Physical and Mental Scores. RESULTS: There were 124 patients (83%) who had functional limb lengthening, and 108 patients (72%) had anatomic limb lengthening. Patients had an average functional limb lengthening of 7 mm (range, -22 to 35) and an average anatomic limb lengthening of 5 mm (range, -16 to 31). Patients undergoing revision for instability experienced significantly greater anatomic lengthening (7.6 versus 4.6, P = .047). Patients who had ≥ 10° of deformity were more likely to be functionally lengthened (91 versus 79%) and had significantly greater average functional lengthening (12 versus 6 mm; P = .003). There was no significant change in clinical outcome scores at 6 weeks and 1 year for patients lengthened ≥ 5 or 10 mm compared to those not lengthened as substantially. CONCLUSIONS: There is major potential for functional and anatomic limb lengthening following revision TKA, with greater preoperative deformity and revision for instability being risk factors for lengthening.

Clinical and Biomechanical Evaluation of Mid-Level Constrained and Posterior-Stabilized Polyethylene Inserts in Primary Total Knee Arthroplasty: An Analysis of 12,674 Cases.

BACKGROUND: Mid-level constraint polyethylene designs provide additional stability in total knee arthroplasty (TKA). The purposes of this study were to (1) compare the survivorship and reason for revision between mid-level inserts and posterior-stabilized (PS) used in primary TKA and (2) evaluate the biomechanical constraint characteristics of mid-level inserts. METHODS: We reviewed all cases of primary TKA performed at our institution from 2016 to 2019 using either PS or mid-level constrained inserts from 1 of 6 manufacturers. Data elements included patient demographics, implants, reasons for revision, and whether a manipulation under anesthesia was performed. We performed finite element analyses to quantify the varus/valgus and axial-rotation constraint of each mid-level constrained insert. A one-to-one propensity score matching was conducted between the patients with mid-level and PS inserts to match for variables, which yielded 2 cohorts of 3,479 patients. RESULTS: For 9,163 PS and 3,511 mid-level TKAs, survivorship free from all-cause revision was estimated up to 5 years and was lower for mid-level than PS inserts (92.7 versus 94.1%, respectively, P = .004). When comparing each company's mid-level insert to the same manufacturer's PS insert, we found no differences in all-cause revision rates (P ≥ .91) or revisions for mechanical problems (P ≥ .97). Using propensity score matching between mid-level and PS groups, no significant differences were found in rates of manipulation under anesthesia (P = .72), all-cause revision (P = .12), revision for aseptic loosening (P = .07), and revision for instability (P = .45). Finite element modeling demonstrated a range in varus/valgus constraint from ±1.1 to >5°, and a range in axial-rotation constraint from ±1.5 to ±11.5° among mid-level inserts. CONCLUSIONS: Despite wide biomechanical variations in varus/valgus and axial-rotation constraint, we found minimal differences in early survivorship rates between PS and mid-level constrained knees.

The John N. Insall Award: Does Melatonin Improve Subjective Sleep Quality After Total Knee Arthroplasty? A Randomized, Placebo-Controlled Trial.

BACKGROUND: Sleep disturbance is a common problem following total knee arthroplasty (TKA). The objective of this study was to determine if exogenous melatonin improves sleep quality following primary TKA. METHODS: A randomized, double-blind, placebo-controlled trial was conducted. A total of 172 patients undergoing unilateral TKA for primary knee osteoarthritis were randomized to receive either 5 mg melatonin (n = 86) or 125 mg vitamin C placebo (n = 86) nightly for 6 weeks. The primary outcome was the Pittsburgh Sleep Quality Index (PSQI) at 6 weeks and 90 days postoperatively. Secondary outcomes included 6-week and 90-day patient-reported outcome measures (PROMs), morphine milligram equivalents prescribed, medication compliance, adverse events, and 90-day readmissions. RESULTS: Mean PSQI scores worsened at 6 weeks before returning to the preoperative baseline at 90 days in both groups. There were no differences in PSQI scores between melatonin and placebo groups at 6 weeks (10.2 ± 4.2 versus 10.5 ± 4.4, P = .66) or 90 days (8.1 ± 4.1 versus 7.5 ± 4.0, P = .43). Melatonin did not improve the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, Lower Extremity Activity Scale, Visual Analog Scale for pain, or Veterans Rand 12 Physical Component Score or Mental Component Score at 6 weeks or 90 days. Poor sleep quality was associated with worse PROMs at 6 weeks and 90 days on univariate and multivariable analyses, but melatonin did not modify these associations. There were no differences in morphine milligram equivalents prescribed, medication compliances, adverse events, or 90-day readmissions between both groups. CONCLUSIONS: Exogenous melatonin did not improve subjective sleep quality or PROMs at 6 weeks or 90 days following TKA. Poor sleep quality was associated with worse patient-reported function and pain. Our results do not support the routine use of melatonin after TKA.

Perioperative Cefazolin for Total Joint Arthroplasty Patients Who Have a Penicillin Allergy: Is It Safe?

BACKGROUND: Cefazolin is the standard of care for perioperative antibiotic prophylaxis in total joint arthroplasty (TJA) in the United States. The potential allergic cross-reactivity between cefazolin and penicillin causes uncertainty regarding optimal antibiotic choice in patients who have a reported penicillin allergy (rPCNA). The purpose of this study was to determine the safety of perioperative cefazolin in PCNA patients undergoing primary TJA. METHODS: We identified all patients (n = 49,842) undergoing primary total hip arthroplasty (n = 25,659) or total knee arthroplasty (n = 24,183) from 2016 to 2022 who received perioperative intravenous antibiotic prophylaxis. Patients who had an rPCNA (n = 5,508) who received cefazolin (n = 4,938, 89.7%) were compared to rPCNA patients who did not (n = 570, 10.3%), and to patients who did not have an rPCNA (n = 43,359). The primary outcome was the rate of allergic reactions within 72 hours postoperatively. Secondary outcomes included the rates of superficial infections, deep infections, and Clostridioides difficile infections within 90 days. RESULTS: The rate of allergic reactions was 0.1% (n = 5) in rPCNA patients who received cefazolin, compared to 0.2% (n = 1) in rPCNA patients who did not (P = .48) and 0.02% (n = 11) in patients who have no rPCNA (P = .02). Allergic reactions were mild in all 5 rPCNA patients who received cefazolin and were characterized by cutaneous symptoms (n = 4) or dyspnea in the absence of respiratory distress (n = 1) that resolved promptly with antibiotic discontinuation and administration of antihistamines and/or corticosteroids. We observed no differences in the rates of superficial infections (0.1 versus 0.2%, P = .58), deep infections (0.3 versus 0.4%, P = .68), or C difficile infections (0.04% versus 0%, P = .99) within 90 days in rPCNA patients who received cefazolin versus alternative perioperative antibiotics. CONCLUSIONS: In this series of more than 5,500 patients who had an rPCNA undergoing primary TJA, perioperative prophylaxis with cefazolin resulted in a 0.1% incidence of allergic reactions that were clinically indolent. Cefazolin can be safely administered to most patients, independent of rPCNA severity. LEVEL OF EVIDENCE: III.

Unicompartmental Knee Arthroplasty Patients Have Lower Joint Awareness and Higher Function at 5 Years Compared to Total Knee Arthroplasties: A Matched Comparison.

BACKGROUND: The purpose of this study was to evaluate postoperative outcomes at minimum 5-year follow-up in patients following unicompartmental knee arthroplasty (UKA) compared to a matched cohort of total knee arthroplasty (TKA) patients. METHODS: Patients who had primarily medial compartment osteoarthritis (OA) who met criteria for medial UKA underwent TKA or medial UKA between 2014 and 2015 at a single institution, matched for age, sex, and body mass index. There were 127 UKAs in 120 patients and 118 TKAs in 116 patients included with minimum 5-year follow-up (range, 6 to 8). Mean age was 69 years (range, 59 to 79) and 71 years (range, 62 to 80) in the UKA and TKA groups, respectively (P = .049). RESULTS: Patients who underwent UKA had significantly higher mean (±SD) Forgotten Joint Scores (87 ± 20 versus 59 ± 34, P < .001); higher Knee Society Scores (88 ± 14 versus 75 ± 21, P < .001); and lower Numeric Pain Rating Scores (0.8 ± 1.6 versus 1.9 ± 2.2, P < .001). Survivorship free from all-cause revision was 96% (95% CI = 93%-99%) and 99% (95% CI = 97%-100%) at 5 years for TKA and UKA, respectively (P = .52). There were 8 both component revisions in the TKA group within 5 years from the date of surgery and 2 UKA conversions to TKA after 5-year follow-up. CONCLUSION: Patients who have medial compartment OA and underwent UKA had significantly lower joint awareness, decreased pain, improved function, and higher satisfaction compared to matched TKA patients at minimum 5-year follow-up while maintaining excellent survivorship.

Survivorship and Clinical Outcomes of Primary Total Knee Arthroplasty Performed in Patients 35 Years of Age and Younger.

BACKGROUND: Total knee arthroplasties (TKAs) for patients aged ≤35 years are rare but necessary for patients who have diseases such as juvenile idiopathic arthritis, osteonecrosis, osteoarthritis, and rheumatoid arthritis. Few studies have examined the 10-year and 20-year survivorship and clinical outcomes of TKAs for young patients. METHODS: A retrospective registry review identified 185 TKAs in 119 patients aged ≤ 35 years performed between 1985 and 2010 at a single institution. The primary outcome was implant survivorship free of revision. Patient-reported outcomes were assessed at 2 time points: 2011 to 2012 and 2018 to 2019. The average age was 26 years (range, 12 to 35). Mean follow-up was 17 years (range, 8 to 33). RESULTS: Survivorship decreased from 84% (95% confidence interval [CI]: 79 to 90) at 5 years to 70% (95% CI: 64 to 77) at 10 years and to 37% (95% CI: 29 to 45) at 20 years. The most common reasons for revision were aseptic loosening (6%) and infection (4%). Risk factors for revision included increasing age at time of surgery (Hazards Ratio [HR] 1.3, P = .01) and use of constrained (HR 1.7, P = .05) or hinged prostheses (HR 4.3, P = .02). There were 86% of patients reporting that their surgery resulted in "a great improvement" or better. CONCLUSION: Survivorship of TKAs in young patients is less favorable than expected. However, for the patients who responded to our surveys, TKA demonstrated substantial pain relief and improvement in function at 17-year follow-up. Revision risk increased with older age and higher levels of constraint.

Patients Undergoing Primary, Cementless TKA had Similar Pain, Opioid Utilization, and Functional Outcomes Compared to Matched Patients With Cemented Fixation.

BACKGROUND: Despite renewed interest in cementless fixation of total knee implants, many surgeons have anecdotal concerns about slower recovery and higher early pain scores. We sought to analyze 90-day opioid utilizations, inhospital pain scores, and patient-reported outcome measures (PROMs) in patients undergoing primary cemented versus cementless total knee arthroplasty (TKA). METHODS: We retrospectively identified a cohort of opioid naïve patients undergoing primary TKA for osteoarthritis. There were 186 patients who had cementless TKAs matched 1:6 with 1,116 who received a cemented TKAs based on age (±6 years), body mass index (BMI) (±5), and sex. We compared inhospital pain scores, 90-day opioid utilizations in morphine milligram equivalents (MMEs), and early postoperative PROMs. RESULTS: The cemented and cementless cohorts had similar lowest (0.09 versus 0.08), highest (7.36 versus 7.34), and average (3.26 versus 3.27) pain scores using numeric rating scale (P > .05). They received similar inhospital (90 versus 102, P = .176), discharge (315 versus 315, P = .483), and total (687 versus 720, P = .547) MMEs. They had similar average inpatient hourly opioid consumption (2.5 versus 2.5 MMEs/hour, P = .965). Average refills 90 days postoperatively were similar in both cohorts (1.5 versus 1.4 refills, P = .893). Also, preoperative, 6-week, 3-month, delta 6-week, and delta 3-month PROMs scores were similar between cemented and cementless cohorts (P > .05) CONCLUSION: This matched study demonstrated similar in-hospital pain scores and opioid utilization, total MMEs prescribed within 90 days, and PROMs at 6 weeks and 3 months postoperatively between cemented and cementless TKAs. LEVEL OF EVIDENCE: III, retrospective cohort study.

Outcomes After Revision Total Knee Arthroplasty From a Specific, Now-Recalled Implant System.

BACKGROUND: A specific total knee arthroplasty (TKA) implant system was recently recalled for high incidence of early polymeric wear and osteolysis. We analyzed the early outcomes of aseptic revision with these implants. METHODS: We identified 202 aseptic revision TKAs of this implant system performed at a single institution between 2010 and 2020. Revision indications included aseptic loosening (n = 120), instability (n = 55), and polymeric wear/osteolysis (n = 27). Components were revised in 145 cases (72%) and isolated polyethylene insert exchange occurred in 57 cases (28%). Kaplan-Meier and Cox proportional hazards analyses were used to determine survivorship free from all-cause rerevision and rerevision risk factors. RESULTS: At 2 and 5 years, survivorship free from all-cause rerevision was 89 and 76% in the polyethylene exchange cohort versus 92 and 84% in the component revision cohort (P = .5). At 2 and 5 years, survivorship in revision with components from the same manufacturer was 89 and 80% compared to 95 and 86% in revision with components from a different manufacturer (P = .2). Among re-revisions (n = 30), cones (37%), sleeves (7%), hinge/distal femoral replacement implants were frequently used (13%). Men had increased risk for rerevision (hazard ratio = 2.3, P = .04). CONCLUSION: In this series of aseptic revision TKAs performed on a now-recalled implant system, survivorship free from rerevision was lower than expected when components from the same manufacturer were utilized, but comparable to contemporary reports when both the components were revised with an alternative implant system. Metaphyseal fixation with cones and sleeves as well as highly constrained implants was frequently utilized at time of rerevision TKA. LEVEL OF EVIDENCE: Level IV.

Wound Complications Are Affected by Different Skin Closure Methods in Primary Hip and Knee Arthroplasty.

BACKGROUND: There is a lack of consensus on optimal skin closure and dressing strategies to reduce early wound complication rates after primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). METHODS: All 13,271 patients at low risk for wound complications undergoing primary, unilateral THA (7,816), and TKA (5,455) for idiopathic osteoarthritis at our institution between August 2016 and July 2021 were identified. Skin closure, dressing type, and postoperative events related to wound complications were recorded during the first 30 postoperative days. RESULTS: The need for unscheduled office visits to address wound complications was more frequent after TKA than THA (2.74 versus 1.78%, P < .001), and after direct anterior versus posterior approach THA (2.94 versus 1.39%, P < .001). Patients who developed a wound complication, had a mean of 2.9 additional office visits. Compared to the use of topical adhesives, skin closure with staples had the highest risk of wound complications (odds ratio 1.8 [1.07-3.11], P = .028). Topical adhesives with polyester mesh had higher rates of allergic contact dermatitis than topical adhesives without mesh (1.4 versus 0.5%, P < .0001). CONCLUSION: Wound complications after primary THA and TKA were often self-limited but increased burden on the patient, surgeon, and care team. These data, which suggest different rates of certain complications with different skin closure strategies, can inform a surgeon on optimal closure methods in their practice. Adoption of the skin closure technique with the lowest risk of complications in our hospital would conservatively result in a reduction of 95 unscheduled office visits and save a projected $585,678 annually.

Use of a novel imageless navigation system reduced fluoroscopy exposure and improved acetabular positioning in anterior approach total hip arthroplasty: a case-control study.

INTRODUCTION: Direct anterior approach (DAA) for total hip arthroplasty (THA) frequently utilizes fluoroscopy. The purpose of this study is to assess the impact of using a novel, imageless THA navigation system on radiation exposure and acetabular cup placement consistency. MATERIALS AND METHODS: This was a retrospective, single-surgeon cohort study of a consecutive group of patients who underwent DAA THA for osteoarthritis. An optic-based imageless navigation system was used to determine intraoperative acetabular inclination and anteversion angles referenced off of a generic coronal and sagittal plane in 71 cases (study group). These were compared with 71 manual cases (control group) for fluoroscopy exposure, operative duration, and acetabular placement variation. Cohorts were similar in their distributions of sex, race, ethnicity, and body mass index. Comparisons between groups were made using independent samples t tests. Alpha error was 0.05. RESULTS: Study patients experienced significantly less fluoroscopy exposure time {3.59 [Standard Deviation (SD) 1.95] vs. 9.15 (SD 5.98) seconds; p < 0.001} and dosage (0.30 [SD 0.23] vs. 0.78 [SD 0.63] mGy; p < 0.001). Study and control patients had similar operative times [82.69 (SD 11.70) vs. 89.54 (SD 14.60) minutes; p = 0.09]. The study group had a significantly lower radiographic variation for inclination and anteversion, based on mean proximity to the centroid of each cohort [3.55 (SD 1.88) vs. 5.39 (SD 3.51); p < 0.001] and also a greater proportion of cases that fell within 1 SD of the mean cohort inclination and anteversion (40.8% vs. 21.1%; p = 0.009). CONCLUSIONS: Use of a novel imageless navigation system for DAA THA significantly reduced fluoroscopic radiation exposure and improved consistency in acetabular cup placement.