Radiographic Cone Zone Classification of Metaphyseal Cone Fixation in Revision Total Knee Arthroplasty.

Background: No objective radiographic scoring system exists to classify metaphyseal cone stability. Our purpose was to create a novel, systematic method to radiographically evaluate metaphyseal cone fixation based on radiographic findings suggestive of cone stability. Methods: A retrospective analysis was conducted of revision total knee arthroplasty patients (6/2015-12/2017) using porous titanium femoral or tibial metaphyseal cones in conjunction with short cemented stems (50 mm-75 mm). Minimum follow-up was 2 years. Survivorship free of aseptic loosening and reoperation, as well as radiographic evaluation using a novel cone zone scoring system were analyzed. Results: Forty-nine revision total knee arthroplasties were included in the study (12 femoral, 48 tibial cones), the majority, performed for aseptic loosening (25/49, 51%). Median follow-up was 39 months (range 25-58). Using the radiographic cone zone scoring method, >90% of all femoral cones were classified as likely stable or stable with strong, statistically significant intraclass correlations between all 3 reviewers. Similarly, >97% of all tibial cones were classified as likely stable or stable, with moderate, statistically significant intraclass correlations between all 3 reviewers. Only 1 femoral and 1 tibial cone were considered at risk of loosening. The study sample demonstrated 100% survivorship free of revision for aseptic loosening without evidence of radiographic loosening in any case. Conclusions: Using a novel systematic cone zone scoring and classification method, the overwhelming majority of femoral and tibial cones were classified as likely stable or stable, with no identified cases of aseptic loosening or related revision. Further studies are needed to validate this objective classification method.

The Influence of Patient Sex on Outcomes Following One-Stage and Two-Stage Revision for Periprosthetic Joint Infection in Total Joint Arthroplasty.

Although females have a higher rate of primary total joint arthroplasty (TJA), males have a higher rate of revision. The literature lacks studies examining the relationship between sex and outcomes following single and two-stage exchange for periprosthetic joint infection (PJI). The purpose of this study was to examine if differences exist in outcomes following revision for chronic PJI between sexes. A retrospective review was performed on all patients with an MSIS confirmed PJI who underwent a single or two-stage exchange at our institution from January 2010 to January 2021. Patient demographics, comorbidity characteristics, and outcomes were collected and compared between males and females. The primary outcome variable was disease-free survival at 1 year following definitive revision. Multivariable logistic regression analysis was performed to determine risk factors for failure. Of the 470 patients meeting final eligibility criteria, 250 were male and 226 were female (2 males and 4 females had a joint infection of either the contralateral side or a different joint and were treated as separate records). Of the patients in the cohort, 80% of the males (200/250) and 80% of the females (181/226) were found to be disease-free at 1-year follow-up (p > 0.99). Multivariable logistic regression analysis showed that nicotine use and diabetes, but not sex, were significant predictors of failure. Our study did not find a relationship between sex and outcome of revision for PJI. Further research is required to determine whether differences exist between males and females in the expression of PJI and outcomes following treatment.

Dual Mobility Articulation in Revision Total Hip Arthroplasty: An American Joint Replacement Registry Analysis of Patients Aged 65 Years and Older.

BACKGROUND: Increasingly, dual mobility (DM) articulations have been used in revision total hip arthroplasty (THA), which may prevent postoperative hip instability. The purpose of this study was to report on outcomes of DM implants used in revision THA from the American Joint Replacement Registry (AJRR). METHODS: Revision THA cases performed between 2012 and 2018 Medicare were eligible and categorized by 3 articulations: DM, ≤32 mm, and ≥36 mm femoral heads. The AJRR-sourced revision THA cases were linked to Centers for Medicare and Medicaid Services (CMS) claims data to supplement (re)revision cases not captured in the AJRR. Patient and hospital characteristics were described and modeled as covariates. Using multivariable Cox proportional hazard models, considering competing risk of mortalities, hazard ratios were estimated for all-cause re-revision and re-revision for instability. Of 20,728 revision THAs, 3,043 (14.7%) received a DM, 6,565 (31.7%) a ≤32 mm head, and 11,120 (53.6%) a ≥36 mm head. RESULTS: At 8-year follow-up, the cumulative all-cause re-revision rate for ≤32 mm heads was 21.9% (95%-confidence interval (CI) 20.2%-23.7%) and significantly (P < .0001) higher than DM (16.5%, 95%-CI 15.0%-18.2%) and ≥36 mm heads (15.2%, 95%-CI 14.2%-16.3%). At 8-year follow-up, ≥36 heads had significantly (P < .0001) lower hazard of re-revision for instability (3.3%, 95%-CI 2.9%-3.7%) while the DM (5.4%, 95%-CI 4.5%-6.5%) and ≤32 mm groups (8.6%, 95%-CI 7.7%-9.6%) had higher rates. CONCLUSION: The DM bearings are associated with lower rates of revision for instability compared to patients who had ≤32 mm heads and higher revision rates for ≥36 mm heads. These results may be biased due to unidentified covariates associated with implant selection.

Treatment Outcomes of Fungal Periprosthetic Joint Infection.

BACKGROUND: Periprosthetic joint infection (PJI) continues to challenge surgeons and patients. The burden of fungal organisms may represent approximately 1% of all PJI. Additionally, fungal PJI is difficult to treat. Most available case series are small and report poor success rates. Fungi are opportunistic pathogens and patients who have fungal PJI are believed to be immunocompromised. Additionally, fungal biofilms are more complex than those formed by other pathogens and confer additional drug resistance. Due to these factors, treatment failure is common. METHODS: A retrospective review of our institutional registry was performed to identify patients treated for fungal PJI. There were 49 patients identified with 8 excluded for not having follow-up, which left 22 knees and 19 hips for analyses. Demographics, clinical characteristics, and surgical details were collected. The primary outcome was failure defined as reoperation for infection following the index surgery for fungal PJI within 1 year of the index surgery. RESULTS: Failure occurred in 10 of 19 knees and 11 of the 22 hips. A higher proportion of patients who have extremity grade C failed treatment, and every patient who failed was host grade 2 or 3. The average number of prior surgeries and time from resection to reimplantation were similar between groups. CONCLUSION: To our knowledge, this represents the largest cohort of fungal PJIs reported in the literature to date. This data supports other literature in that failure rates were high. More study is needed to further understand this entity and improve care for these patients.

Does Treatment at a Specialized Prosthetic Joint Infection Center Improve the Rate of Reimplantation.

BACKGROUND: Two-stage exchange arthroplasty is currently the preferred treatment method for periprosthetic joint infection (PJI). The effectiveness of this strategy in returning patients to premorbid function has recently been challenged. In a review of 18,535 PJI knee patients, 38% did not undergo reimplantation. In another review of 18,156 hip and knee PJI patients, 43% did not undergo reimplantation. These disturbing statistics led us to ask whether treatment at a specialized PJI center could improve the rate of reimplantation compared to the previously noted studies from large national administrative databases. METHODS: A retrospective review of our registry was performed to identify 390 patients who underwent a two-stage exchange after total knee arthroplasty and total hip arthroplasty who had a confirmed chronic bacterial PJI, defined by Musculoskeletal Infection Society criteria, from January 2010 through December 2019. Variables included number of joints resected, number reimplanted, and the number not reimplanted. RESULTS: Of the 390 patients undergoing 2-stage treatment, 386 of 390 (99%) were reimplanted and 4 of 390 (1%) were not reimplanted due to medical issues. CONCLUSION: We have shown that 2-stage treatment at a PJI center significantly improves the rate of reimplantation. A specialized PJI center with experienced revision surgeons doing high volume infection procedures complemented by infectious disease and medical consultants familiar with the special needs of PJI patients may be advantageous. A national network of such centers may have the ability to improve outcomes, standardize treatment protocols, and allow for collaborative research.

Hypoalbuminemia Predicts Failure of Two-Stage Exchange for Chronic Periprosthetic Joint Infection of the Hip and Knee.

BACKGROUND: Nutritionally compromized patients, with preoperative serum albumin (SAB) < 3.5g/dL, are at higher risk for periprosthetic joint infection (PJI) in total joint arthroplasty. The relationship between nutritional and PJI treatment success is unknown. The purpose of this study was to examine the relationship between preresection nutrition and success after first-stage resection in planned two-stage exchange for PJI. METHODS: A retrospective review was performed on 418 patients who had first-stage resection of a planned two-stage exchange for chronic hip or knee PJI between 2014 and 2018. A total of 157 patients (58 hips and 99 knees) were included who completed first stage, had available preop SAB and had a 2-year follow-up. Failure was defined as persistent infection or repeat surgery for infection after resection. Demographic and surgical data were abstracted and analyzed. RESULTS: Among knee patients with preop SAB >3.5 g/dL, the failure rate was 32% (15 of 47) versus a 48% (25 of 40) failure rate when SAB <3.5 g/dL (P = .10). Similarly, the failure rate among hip patients with preop SAB >3.5 g/dL versus 12.5% (3 of 24) versus 44% (15 of 34) for hip patients with SAB <3.5 g/dL (P = .01). Multivariable regression results indicated that patients with SAB< 3.5 g/dL (P = .0143) and Musculoskeletal Infection Society host type C (P = .0316) were at an increased risk of failure. CONCLUSION: Low preoperative SAB and Musculoskeletal Infection Societyhost type-C are independent risk factors for failure following first-stage resection in planned two-stage exchange for PJI. Efforts to nutritionally optimize PJI patients, when possible, may improve the outcome of two-stage exchange.

High Rate of Intramedullary Canal Culture Positivity in Total Knee Arthroplasty Resection for Prosthetic Joint Infection.

BACKGROUND: Periprosthetic infection is a devastating complication following total knee arthroplasty. A 2-stage protocol often includes an interim antibiotic spacer with intramedullary (IM) dowels. However, the necessity of IM dowels has recently been challenged. Specifically, the data supporting bacterial colonization of the IM canal are limited and controversial. The purpose of this study was to identify the rate of positive IM cultures during resection arthroplasty in periprosthetic knee infection. METHODS: A total of 66 IM diaphyseal cultures were taken during resection arthroplasty from 34 patients diagnosed with periprosthetic knee infection. These IM cultures were taken from the femoral and tibial canals using separate sterile instruments. All patients had infected primary total knee arthroplasty implants at the time of resection. RESULTS: Thirty one percent (n = 21) of IM canal cultures in this study were positive from either the tibial or the femoral diaphysis at the time of resection arthroplasty. There were 18 of 21 (86%) of the positive IM canal cultures with concordant intraoperative joint cultures where the IM cultures matched the intraarticular cultures. CONCLUSION: With a 31% positive IM canal culture rate, this study confirms the logic of using IM dowels with an antibiotic spacer to treat periprosthetic knee infection. Since the failure of a 2-stage reimplantation is catastrophic, any attempt to provide additional local antibiotic delivery seems warranted. Since nearly one-third of our patients had positive IM cultures, this simple addition to an antibiotic spacer has the potential to improve 2-stage results. Claims supporting the elimination of IM dowels during resection arthroplasty seem ill-advised.

Total Hip Arthroplasty: Direct Anterior Approach Versus Posterior Approach in the First Year of Practice.

Background: The direct anterior approach (DAA) for total hip arthroplasty (THA) has been popularized as a less invasive technique, however outcomes within the first year of practice after fellowship have not been investigated. The primary aim was to determine differences in complications and outcomes between DAA and posterior approach (PA) in the first year of practice. The secondary aim was to determine if there was a learning curve factor in DAA and PA after fellowship training. Methods: THA cases performed by two surgeons during their first year of practice were reviewed. Overall, 181 THAs (91 DAA, 90 PA) in 168 patients, were performed. Intraoperative differences (blood loss, operative time), hospital stay, complications, reoperations, and revisions were compared. Results: Overall surgical complications were similar between DAA and PA (11% vs. 9%, p=0.64), but complication profiles were different: dislocation (1% vs. 4%, p=0.17), intraoperative femoral fracture (2% vs. 1%, p=0.32), postoperative periprosthetic fractures (2% vs. 3%, p=0.64). neuropraxia (3% vs. 0%, p=0.08). There was no difference in rate of reoperation (1% vs. 3%, p=0.31). There was a difference in rate of revision at final follow-up (0% vs. 6%, p=0.02). DAA consisted of longer operative time (111 vs. 99 minutes; p<0.001), however was only significant in the first 50 cases (p<0.001), while the subsequent cases were similar (p=0.31). There was no difference in the first 50 cases compared to the subsequent cases for either approach regarding blood loss, complications, reoperations, or revisions. Conclusion: DAA and PA for THA performed within the first year of practice exhibit similarly low complication rates, but complication profiles are different. In our series, PA did demonstrate a higher risk of revision at final follow-up. A learning curve is not unique to the DAA. Both DAA and PA THA exhibited a learning curve in the first 50 cases performed at the start of a surgeon's practice. Level of Evidence: III.

Has the time come for regional periprosthetic joint infection centers in the United States? A first-year experience.

Several fields of orthopedics have concluded benefits from volume thresholds. We postulate that we could similarly optimize periprosthetic joint infection (PJI) treatment by creating a regional referral center, concentrating expertise and resources. Here, we review our reasoning and our first-year experience of a PJI referral center in the United States.

High-Dose Antibiotic Cement Spacers Independently Increase the Risk of Acute Kidney Injury in Revision for Periprosthetic Joint Infection: A Prospective Randomized Controlled Clinical Trial.

BACKGROUND: Standard treatment for periprosthetic joint infection (PJI) involves 2-stage exchange with placement of an antibiotic-impregnated cement spacer (ACS). Conflicting evidence exists on the role of ACS in development of acute kidney injury (AKI) after first-stage surgery. In this randomized clinical trial, we aimed to compare the incidence of AKI between the first-stage of a planned 2-stage exchange vs 1-stage exchange. This study design isolates the effect of the ACS in otherwise identical treatment groups. METHODS: The primary outcome variable was AKI, defined as a creatinine ≥1.5 times baseline or an increase of ≥0.3 mg/dL. Risk factors for AKI were evaluated using bivariate statistical tests and multivariable logistic regression. RESULTS: Patients who underwent the first stage of a planned 2-stage exchange were significantly more likely to develop AKI compared with the 1-stage exchange group (15 [22.7%] vs 4 [6.6%], P = .011). On multivariable regression analysis, ACS placement (odds ratio 7.48, 95% confidence limit 1.77-31.56) and chronic kidney disease (odds ratio 3.84, 95% confidence limit 1.22-12.08) were independent risk factors for AKI. CONCLUSION: Our study provides evidence that high-dose antibiotic cement spacers for treatment of PJI are an independent risk factor for AKI. Therefore, efforts to minimize nephrotoxicity should be employed in revision for PJI when possible.

Patient Resilience Influences Opioid Consumption in Primary Total Joint Arthroplasty Patients.

Background: Resilience and depression may influence opioid consumption in patients undergoing primary hip and knee arthroplasty (TJA); however, data evaluating these relationships are limited. Methods: We retrospectively identified 119 patients undergoing TJA who completed preoperative questionnaires to measure resilience (Brief Resilience Scale) and depression (PHQ-9) from 2017 to 2018 at a single institution. Patients were stratified into high, normal, and low resilience groups as well as no, mild, and major depression groups. Opioid use was recorded in morphine milligram equivalents (MMEs). Nonparametric statistical testing was performed with significance level at P < 0.05. Results: Higher levels of resilience correlated with less postoperative inpatient opioid use (P = 0.003). Patients with high resilience were less likely to use preoperative opioids compared to those with low resilience (OR = 6.08, 95% CI [1.230.5]). There was no difference in postoperative outpatient opioid prescriptions between resilience groups. Lower levels of depression correlated with less postoperative inpatient opioid use, though this did not reach statistical significance (P = 0.058). Additionally, there was no significant difference in preoperative opioid use or postoperative outpatient opioid prescriptions between depression groups. Conclusion: Patients with higher levels of resilience are less likely to use opioids before TJA and utilize lower amounts of opioids while inpatient following surgery. Depression correlated with higher postoperative inpatient opioid use; however, the present findings regarding this relationship are inconclusive. Resilience is a psychological trait that may impact opioid use in patients undergoing TJA and should be viewed as a modifiable risk factor. Level of Evidence: III.

Varus Collapse in Total Knee Arthroplasty: Does Fixation or Bone Fail First?

INTRODUCTION: Aseptic tibial loosening is now considered the most common reason that total knee arthroplasties (TKA) fail long term. There are unique subsets of patients that fail into varus alignment of the tibial tray with collapse of the medial proximal tibia. It is currently unknown if the implant fixation fails first or if the proximal medial tibia collapses first. MATERIALS: We performed a retrospective analysis of 88 patients that were revised at our institution secondary to aseptic varus collapse of the proximal tibia. Two fellowship-trained arthroplasty surgeons performed a retrospective analysis on sequential precollapse radiographs in each patient to determine which failed first: the implant fixation (implant-cement or cement-bone interface) or the medial proximal tibia. DISCUSSION: 36/88 (40.9%) patients had a series of precollapse radiographs that could be reviewed. Failure at the implant-cement interface before varus collapse in 23 vs 22 patients, failure at the implant-cement and cement-bone interface before varus collapse in two patients, and contemporaneous failure at the implant-cement interface and varus collapse in 11 vs 12 patients were identified by reviewers one and two, respectively. CONCLUSION: The most frequent mechanism of failure identified was failure of the implant-cement interface followed by subsequent medial tibial varus collapse. Improving implant fixation may decrease the incidence of this unique failure mechanism. We advocate the use of supplemental stem fixation in high-risk patients and optimal cement techniques for all patients as methods of potentially avoiding tibial varus collapse, one of the most frequent modes of long-term failure.

Periprosthetic joint infection rates across primary total hip arthroplasty surgical approaches: a systematic review and meta-analysis of 653,633 procedures.

INTRODUCTION: Evidence demonstrates comparable clinical outcomes across the various surgical approaches to primary total hip arthroplasty (THA). However, high-quality contemporary data regarding periprosthetic joint infection (PJI) risk between direct anterior approach (DAA) and other (THA) approaches is lacking. This systematic review and meta-analysis evaluated PJI rates reported in the literature between the DAA and other approaches. MATERIALS AND METHODS: Five online databases were queried for all studies published from January 1st, 2000 through February 17th, 2021 that reported PJI rates between DAA and other surgical approaches. Studies reporting on primary THAs for osteoarthritis (OA) and that included PJI rates segregated by surgical approach were included. Articles reporting on revision THA, alternative THA etiologies, or minimally invasive techniques were excluded. Mantel-Haenszel (M-H) models were utilized to evaluate the pooled effect of surgical approach on infection rates. Validated risk of bias and methodological quality assessment tools were applied to each study. Multiple sensitivity analyses were conducted to evaluate the robustness of analyses. RESULTS: 28 articles reporting on 653,633 primary THAs were included. No differences were found between DAA cohorts and combined other approaches (OR: 0.95; 95% CI 0.74-1.21; p = 0.67) as well as segregated anterolateral approach cohorts (OR: 0.82, 95% CI 0.64-1.06; p = 0.13). However, DAA patients had a significantly reduced risk of infection compared to those undergoing posterior (OR: 0.66, 95% CI 0.58-0.74; p < 0.0001) and direct lateral (OR: 0.56, 95% CI 0.48-0.65; p < 0.00001) approaches. CONCLUSION: The DAA to primary THA had comparable or lower PJI risk when compared to other contemporary approaches. The results of the most up-to-date evidence available serve to encourage adult reconstruction surgeons who have already adopted the DAA. Additionally, orthopaedic surgeons considering adoption or use of the direct anterior approach for other reasons should not be dissuaded over theoretical concern for a general increase in the risk of PJI. LEVEL OF EVIDENCE: Level III.

Survivorship and Radiographic Evaluation of Metaphyseal Cones With Short Cemented Stems in Revision Total Knee Arthroplasty.

BACKGROUND: The purpose of this study is to evaluate the survivorship and radiographic outcomes of a single design of metaphyseal cone used in conjunction with short cemented stems. METHODS: A retrospective analysis was conducted of revision total knee arthroplasty (rTKA) patients (June 2015 to December 2017) using porous titanium femoral or tibial cones in conjunction with short cemented stems (50-75 mm). Minimum follow-up was 2 years. Survivorship, complications, and a modified Knee Society Radiographic score were analyzed. RESULTS: Forty-nine rTKAs were included in the study (12 femoral cones, 48 tibial cones). Varus-valgus constraint was used in 28 (57%) and a hinged bearing was used in 3 (6%) of these constructs. The majority were index rTKAs of primary components (86%), performed for aseptic loosening (51%) and reimplantation following staged treatment for infection (37%). Median follow-up was 39 months (range 25-58). Using a modified Knee Society Radiographic score, all constructs were classified as stable. Postoperatively, 4 rTKAs were complicated by recurrent infection (8%), periprosthetic fracture 2 (4%), and superficial wound infection 1 (2%). Seven rTKAs (14%) required reoperation. The majority of reoperations (4 rTKAs) were debridement and irrigation with implant retention for infection. Metaphyseal cone constructs with short cemented stems demonstrated 100% survivorship free of revision for aseptic loosening without evidence of radiographic loosening in any case. CONCLUSION: Our results demonstrate excellent outcomes with the use of metaphyseal cones with short cemented stems at mid-term follow-up. This construct avoids the use of long-stem fixation with the associated extraction difficulty, end of stem pain, and potential for malposition at the joint line. LEVEL OF EVIDENCE: IV, Case Series.