Incidence and Risk Factors of Orthostasis After Primary Hip and Knee Arthroplasty.

BACKGROUND: Postoperative orthostatic intolerance can limit mobilization after hip and knee arthroplasty. The literature is lacking on the incidence and risk factors associated with orthostatic intolerance after elective arthroplasty. METHODS: A retrospective case-control study of primary total hip, total knee, and unicompartmental knee arthroplasty patients was conducted. Patients with orthostatic events were identified, and potential demographic and perioperative risk factors were recorded. Orthostatic intolerance was defined as postoperative syncope, lightheadedness, or dizziness, limiting ambulation and/or requiring medical treatment. Statistical analysis was completed using Pearson's chi-square test for categorical data and t-tests for continuous data. Binary logistic regression was performed. RESULTS: A total of 500 consecutive patients were included. The overall incidence of orthostatic intolerance was 18%; 25% in total hip arthroplasty (THA) and 11% in total knee arthroplasty. On univariate analysis, significant risk factors for developing postoperative orthostatic intolerance include older age, female gender, THA surgery, lower American Society of Anesthesiologists class, absence of recreational drug use, lower estimated blood volume, lower preoperative diastolic blood pressure, spinal with monitored anesthesia care (MAC), posterior approach for THA, bupivacaine use in spinal, percent of blood loss, postoperative oxycodone or tramadol use, higher postoperative intravenous fluid volume, and lower postoperative hemoglobin. Multivariate analysis demonstrated persistent significance of female gender, THA surgery, spinal with MAC, bupivacaine use in spinal, and more intravenous fluid administered postoperatively. CONCLUSION: Orthostatic intolerance affects a significant number of arthroplasty patients. Awareness of risk factors and modification of perioperative variables linked to orthostatic intolerance may assist the surgeon in choosing the appropriate surgical setting, educating patients, and improving early postoperative recovery.

Alpha-Defensin Is Not Superior to Traditional Diagnostic Methods for Detection of Periprosthetic Joint Infection in Total Hip Arthroplasty and Total Knee Arthroplasty Patients.

BACKGROUND: Synovial fluid alpha-defensin (AD) may improve diagnostic accuracy of periprosthetic joint infection (PJI) following total knee (TKA) and hip (THA) arthroplasty but is only available as send-out test. This study evaluated laboratory result accuracy between send-out test vs hospital labs and if AD made a difference in treatment plan. METHODS: A retrospective review was performed of 152 consecutive patients with a TKA or THA joint aspiration for painful or clinically concerning joint. Synovial fluid was sent to our institution (hospital-based labs, HBL) and send-out immunoassay laboratory (Synovasure). Patients were scored with specific criteria from validated scoring system for PJI using HBL and Synovasure results. The score with and without AD test was compared to determine if AD impacted patient management. RESULTS: Overall, there was strong agreement between institutions for PJI diagnosis (Cohen's kappa score 0.96). Twenty-nine patients had PJI diagnosis (score ≥6), of which 28 (97%) had positive AD with 1 false-negative result. Sixty-three patients had inconclusive score (between 2 and 5) and 60 patients had negative PJI diagnosis (score ≤1). Of these patients, 5 underwent surgery for infection. Two patients had surgery for positive AD, 2 for positive culture, and 1 because of elevated HBL results. The AD test changed the PJI diagnosis and influenced decision for surgery in only 1.3% (2/152) of patients. CONCLUSION: Minimal differences were found in laboratory values between institutions. The addition of AD may be useful in cases of equivocal laboratory results but does not appear to be necessary for routine diagnosis of PJI after TKA/THA. LEVEL EVIDENCE: Level III.

Alpha-Defensin Offers Limited Utility in Routine Workup of Periprosthetic Joint Infection.

BACKGROUND: Alpha-defensin (AD) is a synovial biomarker included as a minor criterion in the scoring system for diagnosing periprosthetic joint infection (PJI). The purpose of this study is to study the impact of AD on diagnosis and management of PJI. METHODS: Synovial fluid from 522 patients after total knee and hip arthroplasty was retrospective reviewed. Synovial white blood cell count, percentage of neutrophils, and culture from the AD immunoassay laboratory were reviewed with serum erythrocyte sedimentation rate and C-reactive protein values from our institution. A modified version of the 2018 scoring system for diagnosis of PJI was used, only scoring white blood cell count, percentage of neutrophils, erythrocyte sedimentation rate, and C-reactive protein. AD was then analyzed with these scores to determine if AD changed diagnostic findings or clinical management. RESULTS: Eight-two patients were categorized as "infected" (score ≥6), of which 76 patients had positive AD. Of the 6 "infected" patients with negative AD, 2 had positive cultures (Staphylococcus epidermidis). Two-hundred thirteen patients were diagnosed as "possibly infected" (score 2-5). Fourteen of these patients had positive AD, of which 5 had positive cultures assisting with the diagnosis. The AD test changed the diagnosis from "possibly infected" to "infected" in 8 patients (1.5%) but only altered treatment plan in 6 patients (1.1%). A score <2 (not infected) was calculated in 227 patients with no patients having positive AD. CONCLUSION: AD may be beneficial in some cases where laboratory values are otherwise equivocal; however, its routine use for the diagnosis of PJI may not be warranted.

Metal Artifact Reduction Sequence Magnetic Resonance Imaging Abnormalities in Asymptomatic Patients With a Ceramic-on-Ceramic Total Hip Replacement.

BACKGROUND: Metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) has recently gained increased utilization as a screening modality in patients with a total hip arthroplasty (THA). Fluid collections have been documented in asymptomatic patients with various bearing surfaces. The purpose of this study is to determine the frequency and types of MARS MRI-documented abnormalities in asymptomatic patients with a ceramic-on-ceramic (CoC) THA. METHODS: Thirty-seven patients (42 hips) with a minimum 2-year follow-up after THA with CoC THA implants were enrolled in this study. The inclusion criteria were the absence of hip pain and the availability of appropriate follow-up radiographs. All patients underwent a MARS MRI. Abnormalities were documented using a previously described method. RESULTS: Fluid collections were observed in 8 (19%) asymptomatic hips in this cohort. Four of the 8 hips demonstrated intracapsular synovitis, and 3 of these hips had a thickened synovium. Extra-articular fluid collections with direct intra-articular communication were identified in 4 hips, with 2 of these hips demonstrating synovial thickening. No signs of osteolysis were noted on radiographs or the MARS MRI scans. CONCLUSION: Asymptomatic fluid collections occur in patients after CoC THA similar to other bearing surfaces. We continue to follow these patients in an effort to determine the clinical significance and natural history of these findings. LEVEL OF EVIDENCE: Diagnostic Level IV.

Reliability of Spinopelvic Measurements That May Influence the Cup Position in Total Hip Arthroplasty.

BACKGROUND: Spinopelvic pathology has been identified as a potential risk factor for instability after total hip arthroplasty. Spinopelvic radiographic parameters used to diagnose spinopelvic disease may also impact optimal cup placement. The purpose of this study was to assess the arthroplasty surgeon accuracy in making spinopelvic measurements. METHODS: Five fellowship-trained or in-training arthroplasty surgeons reviewed 44 lateral lumbar radiographs in two sessions. All evaluators were instructed how to perform measurements but had little experience in doing so. Traditional measurements included the pelvic tilt (PT), pelvic incidence (PI), and sacral slope (SS), and novel measurements included the acetabular ante-inclination (AI) and pelvic femoral angle. Surgeon measurements were compared with those made by experienced engineers. intraclass coefficients (ICCs) were calculated and interpreted. RESULTS: The interobserver reliability for 4 of 5 of the spinopelvic parameters was good to excellent (ICC >0.75) with the highest reliability seen for PI measurement (ICC = 0.939). Only moderate interobserver reliability was observed for AI measurement (ICC = 0.559). Intraobserver reliability was the highest for the PI and SS, ranging from moderate to good (ICC, 0.718 to 0.896). The lowest intraobserver reliability was seen for the AI (ICC range, 0.026 to 0.545) and pelvic femoral angle (ICC range, 0.035 to 0.828). Surgeon measurements of PT and SS were compared with engineer measurements with extremely poor correlation observed (ICC <0 for all). CONCLUSION: Surgeon intraobserver and interobserver reliability in making novel radiographic measurements was low compared with traditional radiographic measurements. Surgeon reliability in making traditional measurements of the PT and SS was very poor compared with experienced assessors using software-based measurements.

Patient Perception Regarding Potential Effectiveness of Cannabis for Pain Management.

BACKGROUND: Self-reported cannabis use has increased since its recent legalization in many states. The primary objective of this study is to describe patients' beliefs regarding the potential effectiveness of cannabis and gauge patient acceptance of these compounds if prescribed by a physician. METHODS: Five hundred fifty-five consecutive new patients in a total joint arthroplasty (TJA) practice completed a questionnaire at their new patient or preoperative encounter. Questions regarding their beliefs about the potential effectiveness of cannabis for pain management were presented to the patient. Each question was scored in accordance to the agreement of the patient. Data were also collected on patient demographics, and current cannabis, tobacco, and/or alcohol use. RESULTS: Current cannabis use was reported in 20.2% (112/555) of respondents. Patients were interested in using cannabis if prescribed by a physician for acute (75.3%, 418/515) and chronic (74.4%, 415/555) pain. Seventy-seven percent (428/555) of patients believe (strongly agree or agree) that cannabis should be legalized for medical use, whereas only 39% (217/555) strongly agree or agree that cannabis should be legalized for recreational use. Patients strongly agree or agree that cannabis can help with sleep or anxiety, 44.9% (249/555) and 49.4% (274/555) respectively. Most patients had never smoked (53%, 294/555) and drink one or less alcoholic beverage per week (52.1%, 299/555). CONCLUSION: Patients believe that cannabis may be helpful for pain management after TJA and are willing to use if prescribed by their orthopedic provider. Further research is warranted to determine if cannabis is a helpful adjunct to pain management in this patient population.

The James A. Rand Young Investigator's Award: Traditional Intravenous Fluid vs. Oral Fluid Administration in Primary Total Knee Arthroplasty: A Randomized Trial.

BACKGROUND: Optimal perioperative fluid management has not been established in patients undergoing orthopedic surgical procedures. Our purpose was to investigate the effects of perioperative fluid management (ie, preoperative, intraoperative, and postoperative) on patients undergoing total knee arthroplasty (TKA). METHODS: One hundred thirty patients who met inclusion criteria undergoing primary unilateral TKA were prospectively randomized into traditional (TFG) vs oral (OFG) perioperative fluid management groups. The primary outcome was change in body weight (BW). Secondary outcome measures included knee motion, leg girth, bioelectrical impendence, quadriceps activation, functional outcomes testing, Knee injury and Osteoarthritis Outcome Score JR, VR-12, laboratory values, vital signs, patient satisfaction, pain scores, and adverse events. RESULTS: The TFG had increased BW the evening of surgery (7.0 ± 4.3 vs 3.0 ± 3.9, P < .0001), postoperative day (POD) #1 (9.1 ± 4.3 vs 4.7 ± 3.9, P < .0001), and POD #2 (6.2 ± 5.0 vs 4.4 ± 4.0, P = .032). Bioelectrical impedance showed less limb edema in the OFG (4.2 ± 29.7 vs 17.8 ± 30.3, P < .0001) on POD #1. Urine specific gravity differences were seen preoperatively between groups (OFG, more hydrated, P = .002). Systolic blood pressure decrease from the baseline was greater in the OFG on arrival to the floor (19.4 ± 13.5 vs 10.6 ± 12.8, P < .0001) and 8 (23.4 ± 13.3 vs 17.0 ± 12.9, P = .006) and 16 (25.8 ± 13.8 vs 25.8 ± 13.8, P = .046) hours after floor arrival. The TFG had more urine output on POD #1 (3369 mL ± 1343 mL vs 2435 mL ± 1151 mL, P < .0001). The OFG were more likely to go home on POD #1 than the TFG (63 vs 56, P = .02). CONCLUSION: Oral fluid intake with IVF restriction in the perioperative period after TKA may offer short-term benefits with swelling and BW fluctuations. The authors continue to limit perioperative IVFs and encourage patient initiated fluid intake.

Cannabis Use Does Not Affect Outcomes After Total Knee Arthroplasty.

BACKGROUND: The self-reported use of cannabis has increased since its recent legalization in several states. The primary purpose of this study is to report total knee arthroplasty (TKA) outcomes in patients using cannabis. METHODS: Seventy-one patients who underwent a primary unilateral TKA with minimum 1-year follow-up, who self-reported cannabis use, were retrospectively reviewed. The study period was from January 2014 to February 2018 at a single institution. Patients with a history of opioid consumption, alcohol abuse, tobacco, or illicit drug use were excluded. A matched control was conducted based on age, body mass index, gender, smoking status, and insurance type (surrogate of socioeconomic status) in patients with a unilateral TKA who did not report cannabis use. Outcome measures included Knee Society Scores (KSS), range of motion, Veterans RAND-12 mental and physical component scores. No preoperative differences were noted with these measures. Postoperative complications were recorded and reported. RESULTS: No difference in length of stay was noted between the users (46.9 hours ± 15.7) and nonusers (49.3 hours ± 20.4) (P = .464). In-hospital total morphine equivalents did not differ between the 2 groups (user = 137 ± 104 mg, nonuser = 146 ± 117 mg, P = .634). Postoperative range of motion did not differ between users (128.4° ± 10.4°) and nonusers (126.9° ± 7.5°) (P = .346). No mean differences in follow-up KSS (user = 180.1 ± 24.9, nonuser = 172.0 ± 33.9, P = .106) or total change (user = 61.7 ± 32.8, nonuser = 62.7 ± 30.7, P = .852) in KSS were noted. Likewise, no significant mean differences in Veterans RAND-12 (mental component scores: user = 54.8 ± 9.3, nonuser = 55.9 ± 8.79, P = .472; physical component scores: user = 48.3 ± 9.9, nonuser = 45.8 ± 10.1, P = .145) scores were demonstrated. There were no differences in readmissions (user = 5, nonuser = 4, P = .730) or reoperations (user = 5, nonuser = 2, P = .238). CONCLUSION: Cannabis use does not appear to influence (adverse or beneficial) short-term outcomes in patients undergoing a primary TKA. Further studies are warranted to determine the efficacy and safety of cannabis as a constituent of multimodal pain management following TKA before endorsements can be made by orthopedic surgeons.

Influence of Component Geometry on Patellar Mechanics in Posterior-Stabilized Rotating Platform Total Knee Arthroplasty.

BACKGROUND: Patellofemoral complications may cause pain and discomfort, sometimes leading to revision surgery for total knee arthroplasty patients, and patellar implant design has an impact on function of the reconstructed knee. The purpose of this in vivo biomechanics study was to understand the kinematic, functional, strength, and patient-reported outcome data of patients with anatomic and dome patellar implants. METHODS: Satisfactory age-matched, gender-matched, and body mass index-matched patients who underwent rotating-platform total knee arthroplasty from one joint replacement system with either dome (n = 16) or anatomic (n = 16) patellar components were tested in a human motion laboratory using high-speed stereoradiography during an unweighted seated knee extension and a weight-bearing lunge activity. Patellar kinematics, range of motion, strength, and patient-reported outcomes were compared between subjects with anatomic or dome component geometry. RESULTS: Both groups of patients achieved similar functional knee range of motion and reported similar outcomes and satisfaction. On average, patients with the anatomic component had 36% greater extensor strength compared with dome subjects. Patients with anatomic patellar components demonstrated significantly greater flexion of the patella relative to the femur and lower external rotation during the weighted lunge activity. CONCLUSIONS: Relative to the modified dome geometry, patients with anatomic patellar geometry achieved greater patellar flexion which may better replicate normal patellar motion. Patients with anatomic implants may regain more extensor strength compared to patients with dome implants due to geometric differences in the patellar component designs.