Prevalence of Depressive Symptoms in Aseptic Revision Total Knee Arthroplasty Based on the Mode of Failure.

Background: Complications following total knee arthroplasty (TKA) that necessitate revision cause considerable psychological distress and symptoms of depression, which are linked to poorer postoperative outcomes, increased complications, and increased healthcare utilization. We aimed to identify the prevalence of mental health disorders and symptoms preoperatively and postoperatively in patients undergoing aseptic revision TKA and to stratify these patients based on their mechanism of failure. Methods: All patients undergoing aseptic revision TKA from 2008 to 2019 with a minimum 1-year follow-up were retrospectively reviewed at a single institution. Patients (n = 394) were grouped based on 7 failure modes previously described. Patients were considered to have depressive symptoms if their Veterans RAND-12 mental component score was below 42. Preoperative and postoperative Veterans RAND-12 mental component scores at the latest follow-up were evaluated. Results: Overall comparative prevalence of preoperative to postoperative depressive symptoms was 23.4%-18.8%. By mode of failure are as follows: arthrofibrosis (25.8%-16.7%), aseptic loosening (25.3%-18.9%), extensor mechanism disruption (25%-50%), failed unicompartmental knee arthroplasty (8.6%-14.3%), instability (25.7%-17.1%), osteolysis or polyethylene wear (23.1%-23.1%), and patellar failure (11.8%-23.5%). There was no difference in depressive symptoms among failure modes preoperatively (P = .376) or at the latest postoperative follow-up (P = .175). Conclusions: The prevalence of depressive symptoms in revision TKA patients appears to be independent of failure mode. Surgeon awareness and screening for depressive symptoms in this patient population preoperatively with referral for potential treatment may improve early postoperative outcomes.

Cannabis Use Does Not Affect Outcomes After Total Hip Arthroplasty.

BACKGROUND: Cannabis use in patients undergoing arthroplasty has increased with ongoing legalization throughout the United States. The purpose of this study was to report total hip arthroplasty (THA) outcomes in patients self-reporting cannabis use. METHODS: There were 74 patients who underwent primary THA from January 2014 to December 2019 at a single institution with minimum 1-year follow-up who had their self-reported cannabis use retrospectively reviewed. Patients who had a history of alcohol or illicit drug abuse were excluded. A match control was conducted based on age; body mass index; sex; Charlson Comorbidity Index; insurance status; and use of nicotine, narcotics, antidepressants, or benzodiazepines to patients undergoing THA who did not self-report cannabis use. Outcomes included Harris Hip Score (HHS), Hip Disability and Osteoarthritis Outcome Score for Joint Reconstruction (HOOS JR), in hospital morphine milligram equivalents (MMEs) consumed, outpatient MMEs prescribed, in hospital lengths of stay (LOS), postoperative complications, and readmissions. RESULTS: There was no difference in the preoperative, postoperative, or change in Harris Hip Score or HOOS JR between cohorts. There was also no difference in hospital MMEs consumed (102.4 versus 101, P = .92), outpatient MMEs prescribed (119 versus 156, P = .11) or lengths of stay (1.4 versus 1.5 days, P = .32). Also, readmissions (4 versus 4, P = 1.0) and reoperations (2 versus 1, P = .56) were not different between groups. CONCLUSION: Self-reported cannabis use does not influence 1-year outcomes after THA. Further studies are warranted to determine the efficacy and safety of perioperative cannabis use after THA to help guide orthopaedic surgeons in counseling patients.

Hemoglobinopathy is Associated With Total Hip Arthroplasty Indication Even Beyond Sickle Cell Anemia.

Background: The extent to which hemoglobinopathies other than sickle anemia (HbSS) are associated with hip osteonecrosis is unknown. Sickle cell trait (HbS), hemoglobin SC (HbSC), and sickle/ß-thalassemia (HbSßTh) may also predispose to osteonecrosis of the femoral head (ONFH). We sought to compare the distributions of indications for a total hip arthroplasty (THA) in patients with and without specific hemoglobinopathies. Methods: PearlDiver, an administrative claims database, was used to identify 384,401 patients aged 18 years or older undergoing a THA not for fracture from 2010 to 2020, with patients grouped by diagnosis code (HbSS N = 210, HbSC N = 196, HbSßTh N = 129, HbS N = 356). ß-Thalassemia minor (N = 142) acted as a negative control, and patients without hemoglobinopathy as a comparison group (N = 383,368). The proportion of patients with ONFH was compared to patients without it by hemoglobinopathy groups using chi-squared tests before and after matching on age, sex, Elixhauser Comorbidity Index, and tobacco use. Results: The proportion of patients with ONFH as the indication for THA was higher among those with HbSS (59%, P < .001), HbSC (80%, P < .001), HbSßTh (77%, P < .001), and HbS (19%, P < .001) but not with ß-thalassemia minor (9%, P = .6) than the proportion of patients without hemoglobinopathy (8%). After matching, the proportion of patients with ONFH remained higher among those with HbSS (59% vs 21%, P < .001), HbSC (80% vs 34%, P < .001), HbSßTh (77% vs 26%, P < .001), and HbS (19% vs 12%, P < .001). Conclusions: Hemoglobinopathies beyond sickle cell anemia were strongly associated with having osteonecrosis as the indication for THA. Further research is needed to confirm whether this modifies THA outcomes.

Early Total Hip Arthroplasty is a Cost-Effective Treatment for Severe Radiographic Slipped Capital Femoral Epiphysis Over an Individual's Lifetime.

BACKGROUND: Slipped capital femoral epiphysis (SCFE) causes degenerative changes warranting total hip arthroplasty (THA) in approximately 50% of patients by age 60 years. For severe SCFE, a reorienting intertrochanteric osteotomy (ITO) following in situ pinning (ISP) can decrease impingement with hip flexion, but by altering proximal femoral geometry, complicates subsequent conversion THA. We hypothesized that increasing implant survivorship would affect the most cost-effective treatment strategy (ISP followed by ITO [ISP + ITO] with later THA versus ISP alone [ISPa] with earlier THA) over a patient's lifetime. METHODS: A state-transition Markov model was constructed to analyze the cost-effectiveness of either ISPa or ISP + ITO over a 60-year time horizon for children who have severe, stable SCFE. Transition probabilities associated with implant and native hip survivorship, state utilities, and costs were derived from the literature. Sensitivity analyses assessed the model robustness. Incremental cost-effectiveness ratios (ICERs) were compared to a societal willingness to pay (WTP) of $100,000 per quality-adjusted life year (QALY). RESULTS: Over a 60-year horizon, ISPa was costlier ($291,836) than ISP + ITO ($75,227) but achieved overall better outcomes (51.4 QALYs ISPa versus 48.7 QALYs ISP + ITO), rendering ISPa cost-effective with an ICER of $80,980/QALY. Implant survivorship and time horizon were sensitive variables. CONCLUSION: Based upon current implant performance, ISPa with subsequent earlier THA is cost-effective when considering an individual's life expectancy and thereby deserves consideration in patients who have severe SCFE. Without clear level 1 clinical data, our economic model considers a difficult problem, while providing families and clinicians with a framework for understanding treatment options. LEVEL OF EVIDENCE: Economic and decision analysis, Level III.

Poor Correlation Among Metal Hypersensitivity Testing Modalities and Inferior Patient-Reported Outcomes After Primary and Revision Total Knee Arthroplasties.

Background: Metal allergy testing may influence clinical decision-making for patients undergoing a total knee arthroplasty (TKA). Limited data were found to examine the consistency of available testing modalities. This study compares different metal allergy test results and clinical outcomes after primary and revision TKAs in patients with and without metal hypersensitivity. Methods: Primary (n = 28) and revision (n = 20) TKA patients receiving hypoallergenic implants for metal allergies diagnosed by skin patch testing (SPT), lymphocyte proliferation testing (LPT), or lymphocyte transformation testing (LTT) were retrospectively reviewed. The agreement between tests was assessed by percentage and kappa statistic within patients who used multiple testing modalities. Postoperative clinical outcomes of these patients were compared to those of patients without metal hypersensitivity matched by age (±5 years), body mass index (±5), gender, and follow-up duration (±2 years). Results: SPT and LPT showed weak agreement for nickel and minimal agreement for cobalt. SPT and LTT showed minimal agreement for nickel; weak agreement for titanium, bone cement, vanadium, and zirconium; but strong agreement for chromium and cobalt. LPT and LTT agreement was weak. Compared to matched controls, metal hypersensitivity patients undergoing primary TKAs with hypoallergenic implants experienced less improvement in Knee Society Scores, Veterans RAND 12 physical component scores, and range of motion. Patients undergoing revision TKAs for multiple indications including metal hypersensitivity had worse clinical outcomes with significantly worse improvements in Knee Society functional scores compared to matched controls. Conclusions: Metal allergy tests produce conflicting results. Hypersensitivity patients may experience inferior clinical outcomes even with hypoallergenic implants. Clinician awareness may influence the choice of testing and improve preoperative counseling of this patient population.

An Innovative Seven-year Physician Scientist Residency Training Program That Addresses the Shortage of Academic Surgeons.

Due to the declining number of scientifically trained physicians and increasing demand for high-quality literature, our institution pioneered a seven-year Physician Scientist Training Program (PSTP) to provide research-oriented residents the knowledge and skills for a successful academic career. The present study sought to identify orthopaedic surgeons with MD/PhD degrees, residency programs with dedicated research tracks, and to assess the effectiveness of the novel seven-year program in training prospective academic orthopaedic surgeons. Surgeons with MD/PhD degrees account for 2.3% of all 3,408 orthopaedic faculty positions in U.S. residency programs. During the last 23 years, our PSTP residents produced 752 peer-reviewed publications and received $349,354 from 23 resident-authored extramural grants. Eleven of our seven-year alumni practice orthopaedic surgery in an academic setting. The seven-year PSTP successfully develops clinically trained surgeon scientists with refined skills in basic science and clinical experimental design, grant proposals, scientific presentations, and manuscript preparation. (Journal of Surgical Orthopaedic Advances 31(3):144-149, 2022).

Self-Reported Cannabis Use Is Associated With a Lower Rate of Persistent Opioid Use After Total Joint Arthroplasty.

Background: Legalization of cannabis, along with concern over prescription opiate use, has garnered interest in cannabis for adjuvant pain control. This study examines the relationship between cannabis and opioid consumption after total hip (THA) or knee (TKA) arthroplasty. Methods: Patients undergoing primary THA or TKA with minimum 6-month follow-up who self-reported cannabis use were retrospectively reviewed. A total of 210 patients (128 TKAs and 82 THAs) were matched by age; gender; type of arthroplasty; Charlson Comorbidity Index; and use of nicotine, antidepressants, or benzodiazepines to patients who did not self-report cannabis use. Patients receiving an opioid prescription after 90 days postoperatively were classified as persistent opioid users (POUs). Duration of opioid use (DOU) was calculated for non-POU patients as the time between surgery and their last opioid prescription. Differences in inpatient morphine milligram equivalents (MMEs), outpatient MMEs, POU, and DOU were analyzed. Results: Cannabis users required equivalent inpatient and outpatient MMEs. There was no difference in DOU. There was a significant difference in POU between cannabis users and matched controls (1.4% [n = 3] vs 9.5% [n = 20], P < .001, respectively). Grouping patients by TKA or THA, there remained a difference in POU for TKA (1.5% [n = 2] vs 10.9% [n = 14], P = .002) and THA (1.2% [n = 1] vs 7.3% [n = 6], P = .04). There was no difference in inpatient or outpatient MMEs or DOU for THA and TKA patients. Conclusions: There is a reduced rate of POU in patients who self-report perioperative cannabis use. Prospective studies are needed to clarify the role of cannabis as an adjunct to perioperative pain control.

Bacteremia in Patients Undergoing Debridement, Antibiotics, and Implant Retention Leads to Increased Reinfections and Costs.

Background: Debridement, antibiotics, and implant retention (DAIR) is a common treatment for acute prosthetic joint infection (PJI). The effects of concurrent bacteremia at the time of DAIR are poorly understood. This study sought to determine whether patients with bacteremia at the time of DAIR have higher reinfection rates. Material and methods: A retrospective review of a national database was performed. Patients treated with DAIR (hip or knee arthroplasty) after a diagnosis of PJI were identified. DAIR patients who also had a diagnosis of bacteremia were matched to patients without bacteremia by comorbidities and Charlson Comorbidity Index score. The primary outcome was reinfection or continued infection at 90 days and 6, 12, and 24 months after DAIR. Ninety-day Medicare charges were compared between groups. Survival probabilities were used for survival comparisons. Results: A total of 9945 patients underwent DAIR after a diagnosis of PJI. Seven hundred seven patients underwent DAIR with an associated diagnosis of bacteremia. Three hundred thirty-four DAIR patients with bacteremia were successfully matched to patients without bacteremia by age, gender, and comorbidities. DAIR survivorship was significantly worse in those with bacteremia at 90 days (51.5% vs 65.9%) and 6 (43.1% vs 60.5%), 12 (36.5% vs 56.0%), and 24 months (32.6% vs 53.3%) after DAIR. The 90-day costs of DAIR were significantly greater in PJI patients with bacteremia (mean: $14,722 standard deviation: $4086 vs mean: $8,052, standard deviation: $4,153, P < .01). Conclusions: Patients undergoing DAIR with bacteremia are at an increased risk of reinfection or continued infection. Ninety-day costs are significantly increased (over 50%) in patients with bacteremia vs those without bacteremia.

Comet assay for quantification of the increased DNA damage burden in primary human chondrocytes with aging and osteoarthritis.

It is known that chondrocytes from joints with osteoarthritis (OA) exhibit high levels of DNA damage, but the degree to which chondrocytes accumulate DNA damage during "normal aging" has not been established. The goal of this study was to quantify the DNA damage present in chondrocytes obtained from cadaveric donors of a wide age range, and to compare the extent of this damage to OA chondrocytes. The alkaline comet assay was used to measure the DNA damage in normal cartilage from the ankle (talus) and the knee (femur) of cadaveric donors, as well as in OA chondrocytes obtained at the time of total knee replacement. Chondrocytes from younger donors (<45 years) had less DNA damage than older donors (>70 years) as assessed by the percentage of DNA in the comet "tail". In donors between 50 and 60 years old, there was increased DNA damage in chondrocytes from OA cartilage as compared to cadaveric. Talar chondrocytes from 23 donors between the ages of 34 and 78 revealed a linear increase in DNA damage with age (R2  = 0.865, p < 0.0001). A "two-tailed" comet assay was used to demonstrate that most of the accumulated damage is in the form of strand breaks as opposed to alkali-labile base damage. Chondrocytes from young donors required 10 Gy irradiation to recapitulate the DNA damage present in chondrocytes from older donors. Given the potential for DNA damage to contribute to chondrocyte dysfunction and senescence, this study supports the investigation of mechanisms by which hypo-replicative cell types accumulate high levels of damage.

Postoperative Urinary Retention in Modern Rapid Recovery Total Joint Arthroplasty.

Postoperative urinary retention (POUR) is a disruptive complication after modern rapid recovery total joint arthroplasty. This review aims to synthesize the recent literature on POUR in the setting of total joint arthroplasty. The incidence of POUR ranges from 5.5% to 46.3%. The lack of a standardized definition of POUR accounts for some of this variability. Risk factors previously associated with the development of POUR include increasing age, male sex, benign prostatic hyperplasia, use of bupivacaine and intrathecal morphine in spinal anesthesia, glycopyrrolate, and volume of intraoperative intravenous fluid administered. Predictive scoring assessments, such as the International Prostate Symptom Score and a newer predictive nomogram, have not been adequately validated by high-quality studies. The treatment of POUR comprises either intermittent or indwelling urethral catheterization. Higher quality prospective studies are needed to allow for the standardization of all aspects of POUR from its diagnostic criteria to its treatment.

Increased Prevalence of Depressive Symptoms in Patients Undergoing Revision for Periprosthetic Joint Infection.

BACKGROUND: Periprosthetic joint infection (PJI) is a devastating complication after total joint arthroplasty. Patients undergoing revision for PJI may experience psychological distress and symptoms of depression, both of which are linked to poor postoperative outcomes. We, therefore, aim to identify the prevalence of depression and depressive symptoms in patients before treatment for PJI and their link to functional outcomes. METHODS: Patients undergoing either debridement with implant retention (DAIR) or 2-stage exchange for PJI with minimum 1-year follow-up were retrospectively reviewed. The 2-stage (n = 37) and single-stage (n = 39) patients that met inclusion criteria were matched based off age (±5 years), gender, and body mass index (±5) to patients undergoing aseptic revisions. Outcomes evaluated included a preoperative diagnosis of clinical depression and preoperative and postoperative Veterans RAND 12 Item Health Survey mental component score and physical component score. RESULTS: Compared to matched controls, the prevalence of depressive symptoms was significantly greater in patients undergoing 2-stage exchange preoperatively (40.5% vs 10.8%, P < .01) but not postoperatively (21.6% vs 10.8%, P = .20). Patients undergoing DAIR with either preoperative depressive symptoms (31.3 vs 40.9, P = .05) or a preoperative diagnosis of depression (27.7 vs 43.1, P < .01) had significantly lower physical component scores postoperatively. CONCLUSIONS: Patients undergoing 2-stage exchange for PJI have a four times higher prevalence of preoperative depressive symptoms than patients undergoing aseptic revision. Patients undergoing DAIR with depression or preoperative depressive symptoms have lower functional scores postoperatively. Orthopedic surgeon screening of PJI patients with referral for treatment of depression may help improve outcomes postoperatively.

Impact of periprosthetic femoral fracture fixation plating constructs on local stiffness, load transfer, and bone strains.

Secondary femoral fractures after the successful plate-screw fixation of a primary Vancouver type B1 periprosthetic femoral fracture (PFF) have been associated with the altered state of stress/strain in the femur as the result of plating. The laterally implanted condyle-spanning plate-screw constructs have shown promises clinically in avoiding secondary bone and implant failures as compared with shorter diaphyseal plates. Though the condyle-spanning plating has been hypothesized to avoid stress concentration in the femoral diaphysis through increasing the working length of the plate, biomechanical evidence is lacking on how plate length may impact the stress/strain state of the implanted femur. Through developing and experimentally validating finite element (FE) models of 3 cadaveric femurs, this study investigated the impact of plating on bone strains, load transfer and local stiffness, which were compared between FE models of 2 different plating systems that each had a diaphyseal configuration and a condyle-spanning configuration. Under simulated gait-loading, the condyle-spanning constructs of both plating systems were shown to lower the bone strains around the distal fixation screws (up to 24.8% reduction in maximum principal strain and 26.6% reduction in minimum principal strain) and in the distal metaphyseal shaft of the femur (up to 15.9% and 25.7% reductions in maximum and minimum principal strains, respectively), where secondary bone fractures have been typically reported. In the distal diaphyseal and metaphyseal shaft of femur, FE models of the condyle-spanning constructs were shown to increase the local compressive stiffness (up to 152.9% increases under simulated gait-loading) and decrease the transfer of compressive load (37.1% decreases under simulated gait-loading), which may be indicative of the lowered risks of bone damage.

Bone Cement Hypersensitivity in Patients With a Painful Total Knee Arthroplasty: A Case Series of Revision Using Custom Cementless Implants.

Little is known about patients with bone cement hypersenstivity after total knee arthroplasty (TKA). We present 7 patients implanted with 8 TKAs with clinical failure and a cement hypersensitivity diagnosis. All demonstrated hypersensitivity to bone cement via skin patch and/or lymphocyte transformation testing. All 7 patients also showed hypersensitivity to metal, most commonly nickel. Patients underwent custom cementless TKA revision. Prerevision and postrevision outcome measures, radiographs, intraoperative findings, and postrevision complications are reported. Functional scores improved after revision except Veterans RAND-12 mental component scores, which declined. Four patients continue to exhibit symptoms postoperatively, while one patient has had 3 additional surgical procedures. Patients presenting with bone cement hypersensitivity after TKA are particularly challenging. Evidence-based guidelines are lacking, and revision surgery may not relieve the presenting symptoms.

Spinopelvic mobility affects accuracy of acetabular anteversion measurements on cross-table lateral radiographs.

AIMS: Cross-table lateral (CTL) radiographs are commonly used to measure acetabular component anteversion after total hip arthroplasty (THA). The CTL measurements may differ by > 10° from CT scan measurements but the reasons for this discrepancy are poorly understood. Anteversion measurements from CTL radiographs and CT scans are compared to identify spinopelvic parameters predictive of inaccuracy. METHODS: THA patients (n = 47; 27 males, 20 females; mean age 62.9 years (SD 6.95)) with preoperative spinopelvic mobility, radiological analysis, and postoperative CT scans were retrospectively reviewed. Acetabular component anteversion was measured on postoperative CTL radiographs and CT scans using 3D reconstructions of the pelvis. Two cohorts were identified based on a CTL-CT error of ≥ 10° (n = 11) or < 10° (n = 36). Spinopelvic mobility parameters were compared using independent-samples t-tests. Correlation between error and mobility parameters were assessed with Pearson's coefficient. RESULTS: Patients with CTL error > 10° (10° to 14°) had stiffer lumbar spines with less mean lumbar flexion (38.9°(SD 11.6°) vs 47.4° (SD 13.1°); p = 0.030), different sagittal balance measured by pelvic incidence-lumbar lordosis mismatch (5.9° (SD 18.8°) vs -1.7° (SD 9.8°); p = 0.042), more pelvic extension when seated (pelvic tilt -9.7° (SD 14.1°) vs -2.2° (SD 13.2°); p = 0.050), and greater change in pelvic tilt between supine and seated positions (12.6° (SD 12.1°) vs 4.7° (SD 12.5°); p = 0.036). The CTL measurement error showed a positive correlation with increased CTL anteversion (r = 0.5; p = 0.001), standing lordosis (r = 0.23; p = 0.050), seated lordosis (r = 0.4; p = 0.009), and pelvic tilt change between supine and step-up positions (r = 0.34; p = 0.010). CONCLUSION: Differences in spinopelvic mobility may explain the variability of acetabular anteversion measurements made on CTL radiographs. Patients with stiff spines and increased compensatory pelvic movement have less accurate measurements on CTL radiographs. Flexion of the contralateral hip is required to obtain clear CTL radiographs. In patients with lumbar stiffness, this movement may extend the pelvis and increase anteversion of the acetabulum on CTL views. Reliable analysis of acetabular component anteversion in this patient population may require advanced imaging with a CT scan. Cite this article: Bone Joint J 2021;103-B(7 Supple B):59-65.

Incidence and Predictive Risk Factors of Postoperative Urinary Retention After Primary Total Knee Arthroplasty.

BACKGROUND: Postoperative urinary retention (POUR) after total knee arthroplasty (TKA) may cause urologic injury and delay patient discharge. This study measures the incidence of POUR and identifies predictive risk factors. METHODS: Two-hundred seventy-one consecutive patients undergoing primary unilateral TKA were prospectively enrolled. Bladder scans were performed in the postanesthesia care unit (PACU) and every four hours thereafter. POUR was defined as >400cc with inability to void and was treated with catheterization. Patient demographics, urologic history, operative data, perioperative medications, and bladder scanner volumes were investigated with the univariate and multivariate logistic regression analysis. RESULTS: Fifty-five patients (20%) developed POUR. Compared with non-POUR patients, PACU bladder scan volumes were greater in patients who developed POUR (344cc vs 120cc, P < .001). POUR patients had lower BMI (27.8 vs 29.4, P = .03), longer operative duration (83.9 vs 76.0 minutes, P = .002), and lower ASA scores (2.2 vs 2.4, P = .02). Total intravenous fluid was equivalent between groups (1134cc vs 1185cc, P = .41). POUR patients received less narcotics measured by morphine milligram equivalents (16.1 vs 23.9, P < .001). Fifteen variables including spinal type (bupivacaine and ropivacaine) and paralytic use were not predictive of POUR. Potentially predictive variables included anesthetic types administered (spinal, general, regional, and combination) and perioperative administration of nonsteroidal anti-inflammatory drugs (NSAIDs), glycopyrrolate, and muscle relaxants. The multivariate analysis showed that NSAIDs (P = .05) and glycopyrrolate (P = .04) were significant predictors. CONCLUSION: A significant percentage of patients develop POUR after TKA. Select patient demographics and PACU bladder scanning may identify those at risk. Appropriate pain control and judicious use of perioperative NSAIDs and glycopyrrolate may help minimize the risk of POUR.

A Prophylactic Tibial Stem Reduces Rates of Early Aseptic Loosening in Patients with Severe Preoperative Varus Deformity in Primary Total Knee Arthroplasty.

BACKGROUND: Patients with a preoperative varus deformity >8 degrees are at increased risk of aseptic loosening after total knee arthroplasty. This study analyzes the effect of a tibial stem on the rate of aseptic loosening in patients with a severe preoperative varus deformity. METHODS: Patients with a preoperative varus deformity of >8 degrees and 2-year minimum follow-up with a stemmed tibial component (n = 67) were matched 1:2 to patients with a similar preoperative varus deformity with a standard tibial component (n = 134). Radiolucent lines were measured on the tibia at 6 weeks, 1 year, and 2 years postoperatively using the Knee Society Radiographic Evaluation System. Failure was defined as revision due to aseptic loosening of the tibial component. Outcomes were evaluated using Student's t-tests and log-rank tests. RESULTS: Patients with tibial stems had greater preoperative deformity (12.9 vs 11.3 degrees, P = .004). There was no difference in postoperative alignment (1.7 vs 2.1 degrees varus, P = .25) or tibial component angle (1.8 vs 2.1 degrees varus, P = .33). Patients with stems were more likely to have more constraint (44.8% vs 1.5%, P < .001). Progression of radiolucent lines >2 mm was observed in 17.6% (23/134) vs 5.97% (4/67) of patients in the stem group (P = .03). Rates of aseptic loosening were lower in the stem group (0% vs 5.15%, P = .05). CONCLUSION: Despite worse preoperative deformity and higher utilization of constraint, tibial stem use in patients with severe preoperative varus deformity resulted in lower rates of aseptic loosening. Prophylactic use of stems in these patients may help increase implant survival.

Tourniquet Use Improves Cement Penetration and Reduces Radiolucent Line Progression at 5 Years After Total Knee Arthroplasty.

BACKGROUND: Although the effect of tourniquet use during total knee arthroplasty (TKA) on functional outcomes is controversial, there are little data examining cement penetration and implant stability. This study examines the effect of tourniquet use on cement penetration and radiolucent line (RLL) progression. METHODS: Patients undergoing primary total knee arthroplasty with a single surgeon, implant, and cement with minimum 5-year follow-up were retrospectively reviewed. Tourniquet use was defined as 30 minutes minimum, while no tourniquet was 0 minutes. Patients were 1:1 matched (n = 61 per group) by age (±5), gender, body mass index (±5), and follow-up (±2 years). Cement penetration and RLL were measured on the tibia at 6 weeks, and RLL at 1, 2, and 5 years postoperatively using the Knee Society Radiographic Evaluation System. RESULTS: Cement penetration was significantly increased in the tourniquet group in anterior-posterior zones 1 (2.16 vs 1.03 mm, P < .0005), 2 (2.23 vs 1.51 mm, P < .0005), and 5 (8.56 vs 6.3 mm, P = .009), and lateral zones 1 (2.89 vs 2.17 mm, P < .0005), 2 (2.86 vs 2.12 mm, P < .0005), 3P (3.99 vs 3.5 mm, P = .039), and 5 (8.18 vs 5.93 mm, P = .006). Cumulative cement penetration averaged 34.48 vs 43.33 mm in the tourniquet group (P < .005). Progression of RLL >2 mm was observed in 27.8% (17/61) vs 11.4% (7/61) of patients in the tourniquet group (P < .005). There were 2 failures for aseptic tibial loosening in the no tourniquet group. CONCLUSION: Tourniquet use improves cement penetration and reduces RLL progression. Dryer surfaces during cementation may improve penetration, resulting in superior initial fixation strength and potentially reducing the long-term risk of aseptic loosening.

Improved osseointegration using porcine xenograft compared to demineralized bone matrix for the treatment of critical defects in a small animal model.

BACKGROUND: Autograft (AG) is the gold standard bone graft due to biocompatibility, osteoconductivity, osteogenicity, and osteoinductivity. Alternatives include allografts and xenografts (XG). METHODS: We investigated the osseointegration and biocompatibility of a decellularized porcine XG within a critical defect animal model. We hypothesized that the XG will result in superior osseointegration compared to demineralized bone matrix (DBM) and equivalent immune response to AG. Critical defects were created in rat femurs and treated with XG, XG plus bone morphogenetic protein (BMP)-2, DBM, or AG. Interleukin (IL)-2 and IFN-gamma levels (inflammatory markers) were measured from animal blood draws at 1 week and 1 month post-operatively. At 1 month, samples underwent micro-positron-emission tomography (microPET) scans following 18-NaF injection. At 16 weeks, femurs were retrieved and sent for micro-computerized tomography (microCT) scans for blinded grading of osseointegration or were processed for histologic analysis with tartrate resistant acid phosphatase (TRAP) and pentachrome. RESULTS: Enzyme linked immunosorbent assay testing demonstrated greater IL-2 levels in the XG vs. AG 1 week post-op; which normalized by 28 days post-op. MicroPET scans showed increased uptake within the AG compared to all groups. XG and XG + BMP-2 showed a trend toward increased uptake compared with DBM. MicroCT scans demonstrated increased osseointegration in XG and XG + BMP groups compared to DBM. Pentachrome staining demonstrated angiogenesis and endochondral bone formation. Furthermore, positive TRAP staining in samples from all groups indicated bone remodeling. CONCLUSIONS: These data suggest that decellularized and oxidized porcine XG is biocompatible and at least equivalent to DBM in the treatment of a critical defect in a rat femur model.

Bone xenotransplantation: A review of the history, orthopedic clinical literature, and a single-center case series.

BACKGROUND: One-half of all orthopedic surgeries require bone grafting for successful outcomes in fusions, reconstructive procedures, and the treatment of osseous defects resulting from trauma, tumor, infection, or congenital deformity. Autologous bone grafts are taken from the patient's own body and remain the "gold standard" graft choice but are limited in supply and impart significant patient morbidity. Xenograft bone is an attractive alternative from donors with controlled biology, in large supply and at a theoretically lower cost. Clinical results with xenograft bone for orthopedic applications have been mixed in the limited clinical trials published. METHODS: In the current review, we introduce fundamental principles of bone grafting, systematically review all orthopedic clinical studies reporting outcomes on patients transplanted with xenograft bone, and we present our own clinical results from patients grafted with bovine bone in foot and ankle reconstructive procedures. RESULTS: Thirty-one clinical studies were identified for review and the majority (47%) were from spine surgery literature. Favorable results were reported in 44% of studies while 47% of studies reported poor outcomes and discouraged use of xenograft bone products. In our own clinical series, xenograft failed to integrate with host bone in 58% of cases and persistent pain was reported in 83% of cases. CONCLUSIONS: This is the first systematic review of clinical results reported after bone xenotransplantation for orthopaedic surgery applications. Current literature does not support the use of xenograft bone products and our institution's results are consistent with this conclusion. Our laboratory has reported promising pre-clinical results with a xenograft product derived from porcine cancellous bone, but additional testing is required before considering clinical translation.

Success and efficiency of cell seeding in Avian Tendon Xenografts - A promising alternative for tendon and ligament reconstruction.

Decellularized tendon xenografts offer a promising alternative for reconstruction by using ubiquitously available material. This study compares static and centrifugal seeding of avian tendon scaffolds with NIH 3T3 fibroblasts. Incorporation of viable cells was achievable with both techniques, represented by DNA content. Proliferation rate and viability assay showed neither damage by centrifugal force nor superiority of the technique. Cell proliferation after 10 days of culture demonstrated that the scaffold did not hinder 3-D culturing. Confocal laser microscopy revealed structural details as formation of focal adhesions, to provide deeper insight into the process of cell attachment and growth in xenografts.