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Aseptic tibial loosening following primary total knee arthroplasty persists despite technique and device-related advancements. The mechanisms for this mode of failure are not well understood. We hypothesized that knee movement while the cement was curing dispersed lipids at the implant-cement interface and would result in decreased tibial fixation strength.A cadaveric study was performed utilizing 32 torso-to-toe specimens (64 knees). Four contemporary total knee arthroplasty designs were evaluated. Each implant design was randomly assigned to a cadaveric specimen pair with side-to-side randomization. Specimen densitometry was recorded. Each tibial implant was cemented using a standard technique. On one side, the tibial component was held without motion following impaction until complete cement polymerization. The contralateral knee tibial implant was taken through gentle range of motion and stability assessment 7 minutes after cement mixing. Axial tibial pull-out strength and interface failure examination was performed on each specimen.The average pull-out strength for the no motion cohort (5,462 N) exceeded the motion cohort (4,473 N) (P = .001). The mean pull-out strength between implant designs in the no motion cohort varied significantly (implant A: 7,230 N, B: 5,806 N, C: 5,325 N, D 3,486 N; P = .007). Similarly, the motion cohort inter-implant variance was significant (P ≤ .001). Intra-implant pull-out strength was significantly higher in implant A than D. The average pull-out strength was significantly lower in specimens that failed at the implant-cement interface vs bone failures (4,089 ± 2,158 N vs 5,960 ± 2,010 N, P.0025).Knee motion during cement polymerization is associated with significant decreases in tibial implant fixational strength. Reduction in implant pull-out strength was identified with each implant design with motion and varied between designs. Across all tested designs, we recommend limiting motion while cementing the tibial implant to improve fixation strength.

BACKGROUND Two-stage exchange is a commonly used approach for treating chronic periprosthetic joint infections (PJI). A pre-reimplantation threshold value of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) to determine infection eradication and the proper timing of reimplantation remains ill-defined. METHODS We retrospectively reviewed 483 potential patients for eligibility. In total, 178 patients were excluded. In addition, 305 joints were eligible who underwent 2-stage revision for prosthetic hip or knee joint infection (PJI). Serum ESR and CRP were recorded at 8 weeks post resection prior to stage 2 reimplantation. ESR and CRP were analyzed with receiver operating characteristic curves (ROC) for response failure. RESULTS In total, 252 patients had resections for chronic infections while 53 septic patients had resections for acute infections. Forty-one of 252 (16.3%) patients failed reimplantation. Median ESR at the time of reimplantation was 17 (normal less than 20 mm/h). Median CRP was 0.6 (normal less than 0.5 mg/dL). ROC plot for response failure in analyzing ESR found an area under the curve (AUC) of 0.47. ROC plot analyzing CRP found an AUC of 0.57. The ratio of ESR/CRP was also utilized and found an AUC of 0.60. All of the AUC data are in the "fail to discriminate category." CONCLUSION Although improvements in serology can be somewhat reassuring, there are no statistically significant values of ESR or CRP that would predict failure of reimplantation in the 2-stage treatment of PJI. Because we are flying blind consideration should be made for mandatory pre-reimplantation aspirates. LEVEL OF EVIDENCE Level IV, Retrospective Case Series.

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.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.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.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.IV, Case Series.

The purpose of this study was to evaluate the conversion rate of knee arthroscopy to ipsilateral total knee arthroplasty (TKA) within 2 years in patients aged 50 or older at the time of arthroscopy. The administrative database from a large, physician-owned orthopaedic practice (>100 surgeons) was queried to identify patients over the age of 50 who had undergone arthroscopic knee surgery between January 1, 2006 and January 2, 2015. The subset of patients who converted to TKA within 2 years after knee arthroscopy was identified and matched by age and sex to a control population that did not convert to TKA. Rates of conversion to TKA were calculated. Prearthroscopic digital radiographs were reviewed and Kellgren–Lawrence (KL) grades were compared among case and control populations. Univariable analyses and multivariable regression analysis were performed. Eight hundred seven of 16,061 (5.02%) patients aged 50 or older were converted to TKA within 2 years following ipsilateral knee arthroscopy. In univariable analysis, the rate of conversion to TKA in patients aged between 50 and 54 was 2.94%, compared with 4.44% in patients aged between 55 and 64, and 8.32% in patients 65 or older (p

Wound breakdown following a total joint arthroplasty is a difficult problem to manage. Early aggressive debridement and closure is essential to prevent a subsequent prosthetic joint infection. Open management of a wound that communicates directly with the joint in the form of wet to dry dressings, iodoform packings, or a non-incisional wound vac should be avoided. Such treatment is inappropriate and leads to difficult to treat multi-organism infections and less than optimal results. (Journal of Surgical Orthopaedic Advances 30(4):263-264, 2021).

When faced with the necessity of surgery in a previously operated knee, pre-operative planning and understanding of the vascular anatomy to the front of the knee is essential. Blood flow to the anterior aspect of the knee comes from medial to lateral. Therefore, in the case of multiple previous knee incisions the most lateral incision should always be chosen to avoid skin necrosis. The concept of a safe distance between incisions is inappropriate, risks extensive skin necrosis, and should be abandoned. (Journal of Surgical Orthopaedic Advances 30(4):253-255, 2021).

Background Advances in technique and perioperative blood management have improved transfusion rates following unilateral primary total joint arthroplasty and led some centers to change their preoperative blood ordering protocols. The purpose of this study is to determine whether deleting type and screens (T&S) from preoperative order sets was safe for patients undergoing primary total knee (TKA) and total hip arthroplasty (THA) and to identify patients who required allogenic blood transfusion. Methods Prospectively collected data were reviewed to identify any patient with a hemoglobin (Hgb) drawn within 30 days of surgery who received a transfusion following a unilateral primary TKA or THA. Results A total of 1255 patients met inclusion criteria. Of the total, 682 (54%) were TKAs and 573 (46%) were THAs. The mean preoperative Hgb was 11.5 g/dL with an average delta Hgb of 3.6 g/dL on postoperative day 1. No patient required an intraoperative transfusion. Fourteen patients (mean age and body mass index, 67.9 and 29.0) required a transfusion (1.1%) for postoperative blood loss anemia. Of those transfused, 13 (93%) of the patients underwent THA with the mean estimated blood loss of 378.6 mL. The total cost for a patient obtaining a T&S is $191.27. Conclusion In our series, the risk of blood transfusion was rare (1.1%) and occurred only secondary to postoperative blood loss anemia. There were no cases of intraoperative complication requiring urgent or emergent blood transfusion. Removing T&S from standard order sets for patients undergoing primary TKA or THA appears to be a safe and cost-effective practice.

Aims Patients with abnormal spinopelvic mobility are at increased risk for instability. Measuring the change in sacral slope (ΔSS) can help determine spinopelvic mobility preoperatively. Sacral slope (SS) should decrease at least 10° to demonstrate adequate posterior pelvic tilt. There is potential for different ΔSS measurements in the same patient based on sitting posture. The purpose of this study was to determine the effect of sitting posture on the ΔSS in patients undergoing total hip arthroplasty (THA). Methods In total, 51 patients undergoing THA were reviewed to quantify the variability in preoperative spinopelvic mobility when measuring two different sitting positions using SS for planning. Results A total of 32 patients had standardized relaxed sitting radiographs, while 35 patients had standardized flexed sitting images. Of the 32 patients with relaxed sitting views, the mean ΔSS was 20.7° (SD 8.9°). No patients exhibited an increase in SS during relaxed sitting (i.e. anterior pelvic tilt or so-called reverse accommodation). Of the 35 patients with flexed sitting radiographs, the mean ΔSS was only 2.1° (SD 9.7°) with 16/35 (45.71%) showing anterior pelvic tilt, or so-called reverse accommodation, unexpectedly increasing the sitting SS compared to the standing SS. Overall, 18 patients had both relaxed sitting and flexed sitting radiographs. In patients with both types of sitting radiographs, the mean relaxed sit to stand ΔSS was 18.06° (SD 6.07°), while only a 3.00° (SD 10.53°) ΔSS was noted when flexed sitting. There was a mean ΔSS difference of 15.06° (SD 7.67°) noted in the same patient cohort depending on sitting posture (p < 0.001). Conclusion A 15° mean difference was noted depending on the sitting posture of the patient. Since decisions on component position can be made on preoperative lateral sit-stand radiographs, postural standardization is crucial. If using ΔSS for preoperative planning, the relaxed sitting radiograph is preferred. Cite this article: Bone Joint J 2020;102-B(7 Supple B):41–46.

Background Revision of monoblock metal-on-metal (MoM) total hip arthroplasty (THA) is associated with high complication rates. Limited revision by conversion to a dual mobility (DM) without acetabular component extraction may mitigate these complications. However, the concern for polyethylene wear and osteolysis remains unsettled. This study investigates the results of DM conversion of monoblock MoM THA compared to formal acetabular revision. Methods One hundred forty-three revisions of monoblock MoM THA were reviewed. Twenty-nine were revisions to a DM construct, and 114 were complete revisions of the acetabular component. Mean patient age was 61, 54% were women. Components used, acetabular cup position, radiographic outcomes, serum metal ion levels, and HOOS Jr clinical outcome scores were investigated. Results At 3.9 years of follow-up (range 2-5), there were 2 revisions (6.9%) in the DM cohort, 1 for instability and another for periprosthetic fracture. Among the formal acetabular revision group there was a 20% major complication rate (23/114) and 16% underwent revision surgery (18/114) for aseptic loosening of the acetabular component (6%), deep infection (6%), dislocation (4%), acetabular fracture (3%), or delayed wound healing (6%). In the DM cohort, there were no radiographic signs of aseptic loosening, component migration, or polyethylene wear. One DM patient had a small posterior metadiaphyseal femur lesion that will require close monitoring. There were no other radiographic signs of osteolysis. There were no clinically significant elevations of serum metal ion levels. HOOS Jr scores were favorable. Conclusion Limited revision with conversion to DM is a viable treatment option for failed monoblock MoM THA with lower complication rates than formal revision. Limited revision to DM appears to be a safe option for revision of monoblock MoM THA with a cup in good position and an internal geometry free of sharp edges or articular surface damage. Longer follow-up is needed to demonstrate any potential wear implications of these articulations.

Open wound management in prosthetic joint infection (PJI) patients has been used in problematic dehisced wounds hoping to stimulate granulation tissue and closure. However, infections that start as a monomicrobial PJI can become polymicrobial with resultant worse outcomes following open wound management. This study assessed the relationship between open wound management and the development of polymicrobial periprosthetic joint infections.We reviewed patients referred with a synovial cutaneous fistula. Patients with an open wound measuring less than 2 cm and less than two weeks of open wound management were excluded. Variables included original organisms cultured, type and length of open wound management, and organisms cultured at the time of revision infection surgery.Of the 65 patients with a previous monomicrobial infection treated with open wound management, 22/65 (34%) progressed to a polymicrobial infection. Thirty (46%) wounds were packed open with gauze, 20 (31%) were managed with negative pressure wound therapy, and 15 (23%) had surface dressings only. Of the 22 patients who converted to a polymicrobial infection, only 10 (45%) were infection free at follow-up. In contrast, 30 of 43 patients (70%) whose infections remained monomicrobial were infection free at follow-up.Open wound management can lead to conversion from a monomicrobial to a polymicrobial PJI, a rate of 34% in this series. Open prosthetic wound management should be discontinued for a fear of converting a monomicrobial infection to a difficult to treat polymicrobial infection. Surgeons must be prudent in the use of open wound management.Level IV, Retrospective Case Series.

Long-term reinfection and mortality rates and clinical outcomes with sufficient subject numbers remain limited for patients undergoing two-stage exchange arthroplasty for chronic periprosthetic knee infections. The purpose of this study was to determine the long-term reinfection, complication, and mortality following reimplantation for two-stage exchange following knee arthroplasty.Retrospective review of 178 patients who underwent two-stage exchange knee arthroplasty for chronic PJI at three large tertiary referral institutions with an average of 6.63-year follow-up from reimplantation from 1990 to 2015. Rates of reinfection, mortality, and all-cause revision were calculated along with the cumulative incidence of reinfection with death as a competing factor. Risk factors for reinfection were determined using Cox multivariate regression analysis.Overall rate of infection eradication was 85.41%, with a mortality rate of 30.33%. Patients with minimum 5-year follow-up (n = 118, average 8.32 years) had an infection eradication rate of 88.98%, with a mortality rate of 33.05%.This is a large series with long-term follow-up evaluating outcomes of two-stage exchange knee arthroplasty resulting in adequate infection eradication and high mortality. Results were maintained at longer follow-up. This technique should be considered in patients with chronic PJI; however, realistic expectations regarding long-term outcomes must be discussed with patients.

Background All aspects of the arthroplasty pathway must be scrutinized to maximize value and eliminate unnecessary cost. Radiology providers’ contracts with hospitals often call for readings of all radiographs. This policy has little effect on patient care when intraoperative radiographs are taken and used to make real-time decisions. In order to determine the value of radiologist overreads, we asked 3 questions: what was the delay between the time an intraoperative radiograph was taken and time the report was generated, were the overreads accurate, and what is the associated cost? Methods Two hundred hip and knee radiograph reports generated over 6 months during 391 cases were reviewed. The time the report was dictated was compared to the time taken and time of surgery completion. To determine accuracy, each overread was rated as accurate or inaccurate. The cost of the overread was determined by multiplying the number of radiographs times the radiology fee less the technical fee. Results Median delay between taking the radiograph and filing the report was 45 minutes (range, 0-9778 minutes). Only 31.5% were filed before completion of the procedure. And 18.0% (36/200) were considered inaccurate despite lenient criteria. The reading fee for hip radiographs was $52.00, and for knee radiographs was $38.00, representing a total cost of $10,182 in our select series. This cost projects to $43,614 annually at our facility. Conclusion Radiology overreads of intraoperative radiographs have no effect on real-time decision-making. In the era of value-based care, payors should stop paying for overreads and reimburse providers who actually read the films intraoperatively.

AimsDebridement, antibiotics, and implant retention (DAIR) remains one option for the treatment of acute periprosthetic joint infection (PJI) despite imperfect success rates. Intraosseous (IO) administration of vancomycin results in significantly increased local bone and tissue concentrations compared to systemic antibiotics alone. The purpose of this study was to evaluate if the addition of a single dose of IO regional antibiotics to our protocol at the time of DAIR would improve outcomes.MethodsA retrospective case series of 35 PJI TKA patients, with a median age of 67 years (interquartile range (IQR) 61 to 75), who underwent DAIR combined with IO vancomycin (500 mg), was performed with minimum 12 months' follow-up. A total of 26 patients with primary implants were treated for acute perioperative or acute haematogenous infections. Additionally, nine patients were treated for chronic infections with components that were considered unresectable. Primary outcome was defined by no reoperations for infection, nor clinical signs or symptoms of PJI.ResultsMean follow-up for acute infection was 16.5 months (12.1 to 24.2) and 15.8 months (12 to 24.8) for chronic infections with unresectable components. Overall non-recurrence rates for acute infection was 92.3% (24/26) but only 44.4% (4/9) for chronic infections with unresectable components. The majority of patients remained on suppressive oral antibiotics. Musculoskeletal Infection Society (MSIS) host grade was a significant indicator of failure (p < 0.001).ConclusionThe addition of IO vancomycin at the time of DAIR was shown to be safe with improved results compared to current literature using standard DAIR without IO antibiotic administration. Use of this technique in chronic infections should be applied with caution. While these results are encouraging, this technique requires longer follow-up before widespread adoption. Cite this article: Bone Joint J 2021;103-B(6 Supple A):185–190.

BACKGROUND We analyzed whether the total hospital cost in a 90-day bundled payment period for ceramic-on-polyethylene (C-PE) and ceramic-on-ceramic (COC) total hip arthroplasty (THA) bearings was changing over time, and whether the cost differential between ceramic bearings and metal-on-polyethylene (M-PE) bearings was approaching the previously published tipping point for cost-effectiveness of US$325. METHODS A total of 245,077 elderly Medicare patients (65+) who underwent primary THA between 2010 and 2015 were identified from the United States Medicare 100% national administrative hospital claims database. The total inpatient cost, calculated up to 90 days after index discharge, was computed using cost-to-charge ratios, and hospital payment was analyzed. The differential total inpatient cost of C-PE and COC bearings, compared to metal-on-polyethylene (M-PE), was evaluated using parametric and nonparametric models. RESULTS After adjustment for patient and clinical factors, and the year of surgery, the mean hospital cost up to 90 days for primary THA with C-PE or COC was within ±1% of the cost for primary THA with M-PE bearings (P < .001). From the nonparametric analysis, the median total hospital cost was US$296-US$353 more for C-PE and COC than M-PE. Cost differentials were found to decrease significantly over time (P < .001). CONCLUSION Patient and clinical factors had a far greater impact on the total cost of inpatient THA surgery than bearing selection, even when including readmission costs up to 90 days after discharge. Our findings indicate that the cost-effectiveness thresholds for ceramic bearings relative to M-PE are changing over time and increasingly achievable for the Medicare population.

Background The position of the acetabular component in total hip arthroplasty (THA) is critical for success. However, this remains the most variable aspect of the surgery. We hypothesized that there is wide variation in pelvic orientation in the lateral decubitus position. We sought to determine the variability in pelvic positioning and the frequency of pelvic malposition during THA in lateral decubitus with regard to pelvic tilt and pelvic rotation. Methods We analyzed preoperative standing and intraoperative anteroposterior pelvis X-rays in 248 consecutive THAs performed in lateral decubitus by one surgeon. Pelvic tilt and rotation were determined for preoperative and intraoperative X-rays. Proper intraoperative positioning was defined as less than 10° change in tilt or rotation between preoperative and intraoperative X-rays. Results With regard to pelvic tilt, the intraoperative position was proper in 188 (76%) cases. There was a pelvic tilt discrepancy of 10°-20° in 43 (17.5%) cases and greater than 20° in 16 (6.5%) patients. With regard to pelvic rotation, the intraoperative position was proper in 202 (81%) cases. There was a pelvic rotation discrepancy of 10°-20° in 38 (15.4%) cases and greater than 20° in 7 (2.8%) cases. In 248 cases, only 154 (62.1%) had intraoperative positioning within 10° of preoperative tilt and axial rotation. Pelvic malposition occurred in 38% of cases overall. Conclusion There is wide variation in pelvic orientation in lateral decubitus and frequent discrepancy in pelvic tilt and rotation between preoperative and intraoperative anteroposterior X-rays. Anatomic landmarks should be used to guide acetabular component positioning. Level of Evidence III Diagnostic.

Background Patient optimization is becoming increasingly important before arthroplasty to ensure outcomes. It has been suggested that depression is a modifiable risk factor that should be corrected preoperatively. It remains to be determined whether psychological intervention before surgery will improve outcomes. We theorized that the use of preoperative depression scales to predict postoperative outcomes may be influenced by the pain and functional disability of arthritis. To determine whether depression is a modifiable risk factor that should be corrected preoperatively we asked the following questions: (1) What is the prevalence of depression in arthroplasty patients preoperatively? (2) Do depressive symptoms improve after surgery? (3) Is preoperative depression associated with outcome? Methods Patients scheduled for surgery completed a patient health questionnaire (PHQ-9) to assess the presence and severity of depression pre-operatively and one year post-operatively. Results Sixty-five of the 282 patients had a PHQ-9 score >10 indicating moderate depression and 57 (88%) improved to P = .0012). Ten patients had a PHQ-9 score >20 indicating severe depression and 9 (90%) improved to P = .10). Of the 65 patients who had a PHQ-9 score >10 preoperatively, the median postoperative Hip Disability and Osteoarthritis Outcome Score (N = 40) was 92.3, while the median postoperative Knee Injury and Osteoarthritis Outcome Score (N = 25) was 84.6. The median postoperative Hip Disability and Osteoarthritis Outcome Score and Knee Injury and Osteoarthritis Outcome Score in nondepressed patients were 96.2 and 84.6, respectively ( P = .9041). Conclusion By diminishing pain and improving function through arthroplasty, depression symptoms improve significantly. Patients with depressive symptoms preoperatively had similar postoperative outcome scores compared to non-depressed patients. Patients should not be denied surgical intervention through optimization programs that include a depression scale threshold. Level of Evidence III.

BACKGROUND Investigations into reimbursement trends for primary and revision arthroplasty procedures have demonstrated a steady decline over the past several years. Revision total hip arthroplasty (rTHA) due to infection (rTHA-I) has been associated with higher resource utilization and complexity, but long-term inflation-adjusted data have yet to be compared between rTHA-I and rTHA due to aseptic complications (rTHA-A). The present study was performed to analyze temporal reimbursement trends regarding rTHA-I procedures compared with those for rTHA-A procedures. METHODS The Centers for Medicare & Medicaid Services (CMS) Physician Fee Schedule Look-Up Tool was used to extract Medicare reimbursements associated with 1-stage and 2-stage rTHA-I as well as 1-stage rTHA-A procedures from 2002 to 2019. Current Procedural Terminology (CPT) codes for rTHA were grouped according to the American Academy of Orthopaedic Surgeons coding reference guide. Monetary values were adjusted for inflation using the consumer price index (U.S. Bureau of Labor Statistics; reported as 2019 U.S. dollars) and used to calculate the cumulative and average annual percent changes in reimbursement. RESULTS Following inflation adjustment, the physician fee reimbursement for rTHA-A decreased by a mean [and standard deviation] of 27.26% ± 3.57% (from $2,209.11 in 2002 to $1,603.20 in 2019) for femoral component revision, 27.41% ± 3.57% (from $2,130.55 to $1,542.91) for acetabular component revision, and 27.50% ± 2.56% (from $2,775.53 to $2,007.61) for both-component revision. Similarly, for a 2-stage rTHA-I, the mean reimbursement declined by 18.74% ± 3.87% (from $2,063.36 in 2002 to $1,673.36 in 2019) and 24.45% ± 3.69% (from $2,328.79 to $1,755.45) for the explantation and reimplantation stages, respectively. The total decline in physician fee reimbursement for rTHA-I ($1,020.64 ± $233.72) was significantly greater than that for rTHA-A ($580.72 ± $107.22; p < 0.00001). CONCLUSIONS Our study demonstrated a consistent devaluation of both rTHA-I and rTHA-A procedures from 2002 to 2019, with a larger deficit seen for rTHA-I. A continuation of this trend could create substantial disincentives for physicians to perform such procedures and limit access to care at the population level. LEVEL OF EVIDENCE Economic and Decision Analysis Level IV. See Instructions for Authors for a complete description of levels of evidence.

Aims Recent improvements in surgical technique and perioperative blood management after total joint replacement (TJR) have decreased rates of transfusion. However, as many surgeons transition to outpatient TJR, obtaining routine postoperative blood tests becomes more challenging. Therefore, we sought to determine if a preoperative outpatient assessment tool that stratifies patients based on numerous medical comorbidities could predict who required postoperative haemoglobin (Hb) measurement. Methods We performed a prospective study of consecutive unilateral primary total knee arthroplasties (TKAs) and total hip arthroplasties (THAs) performed at a single institution. Prospectively collected data included preoperative and postoperative Hb levels, need for blood transfusion, length of hospital stay, and Outpatient Arthroplasty Risk Assessment (OARA) score. Results A total of 504 patients met inclusion criteria. Mean age at time of arthroplasty was 65.3 years (SD 10.2). Of the patients, 216 (42.9%) were THAs and 288 (57.1%) were TKAs. Six patients required a blood transfusion postoperatively (1.19%). Transfusion after surgery was associated with lower postoperative day 1 Hb (median of 8.5 (interquartile range (IQR) 7.9 to 8.6) vs 11.3 (IQR 10.4 to 12.2); p < 0.001), longer length of stay (1 day (IQR 1 to 1) vs 2 days (IQR 2 to 3); p < 0.001), higher OARA score (median of 60.0 (IQR 40 to 75) vs 5.0 (IQR 0-35); p = 0.001), and total hip arthroplasty (p < 0.001). All patients who received a transfusion had an OARA score > 34; however, this did not reach statistical significance as a screening threshold. Conclusion Risk of blood transfusion after primary TJR was uncommon in our series, with an incidence of 1.19%. Transfusion was associated with OARA scores > 60. The OARA score, not American Society of Anesthesiologists grade, reliably identified patients at risk for postoperative blood transfusion. Selective Hb monitoring may result in substantial cost savings in the era of cost containment. Cite this article: Bone Joint J 2021;103-B(1):65–70.

BACKGROUND As orthopaedic physician fees continue to come under scrutiny by the U.S. Centers for Medicare & Medicaid Services (CMS), there is a continued need to evaluate trends in reimbursement rates across contemporary time intervals. Although substantially lower work relative value units (RVUs) have been previously demonstrated for septic revision total knee arthroplasty (TKA) compared with aseptic revisions, to our knowledge, there has been no corresponding analysis comparing total physician fees. Therefore, the purpose of our study was to analyze temporal trends in Medicare physician fees for septic and aseptic revision TKAs. METHODS Current Procedural Terminology (CPT) codes related to septic 1-stage and 2-stage revision TKAs and aseptic revision TKAs were categorized. From 2002 to 2019, the facility rates of physician fees associated with each CPT code were obtained from the CMS Physician Fee Schedule Look-Up Tool. Monetary data from Medicare Administrative Contractors at 85 locations were used to calculate nationally representative means. All total physician fee values were adjusted for inflation and were translated to 2019 U.S. dollars using Consumer Price Index data from the U.S. Bureau of Labor Statistics. Cumulative annual percentage changes and compound annual growth rates (CAGRs) were computed utilizing adjusted physician fee data. RESULTS After adjusting for inflation, the total mean Medicare reimbursement (and standard deviation) for aseptic revision TKA decreased 24.83% ± 3.65% for 2-component revision and 24.21% ± 3.68% for 1-component revision. The mean septic revision TKA total Medicare reimbursement declined 23.29% ± 3.73% for explantation and 33.47% ± 3.24% for reimplantation. Both the dollar amount (p < 0.0001) and the percentage (p < 0.0001) of the total Medicare reimbursement decline for septic revision TKA were significantly greater than the decline for aseptic revision TKA. CONCLUSIONS Septic revision TKAs have been devalued at a rate greater than their aseptic counterparts over the past 2 decades. Coupled with our findings, the increased resource utilization of septic revision TKAs may result in financial barriers for physicians and subsequently may reduce access to care for patients with periprosthetic joint infections. CLINICAL RELEVANCE The devaluation of revision TKAs may result in reduced patient access to infection management at facilities unable to bear the financial burden of these procedures.

Background Aseptic tibial loosening is a frequent cause of long-term failure following primary cemented total knee replacement. Failure of the tibial implant can occur at the implant-cement interface or at the cement-bone interface. Currently, it is unknown at which interface failure occurs in cases of aseptic tibial loosening. The following study was designed to determine which interface represents the “weak link” for tibial implant fixation. Methods We performed a retrospective analysis of 149 patients who were revised secondary to aseptic tibial loosening at our institution from 2005 to 2017. Operative reports and radiographs were reviewed on each patient to determine the location and pattern of fixation failure. Results Implant failure was more prevalent at the implant-cement than cement-bone interface, 140/149 (94.0%) vs 9/149 (6.0%). Additionally, we noted 2 distinct patterns of failure in patients that loosened at the implant-cement interface. Ninety of 140 (64.3%) patients developed varus collapse pattern of failure. Forty-nine of 140 (35.0%) patients developed failure between the implant-cement interface without angulation. All 149 patients had heterotopic bone formation anterior to the tibial baseplate, which was consistent regardless of which interface failed. Conclusion The most frequent interface failure identified in our study was at the implant-cement interface, 140/149 (94.0%). This finding has substantial clinical ramifications. Because failure was predominantly at the implant-cement interface there may be design opportunities for increasing implant fixation to cement. Implants with improved undersurface tibial tray features may be necessary to mitigate the risk of failure at this interface, especially in overly active patients or those with elevated body mass indices.

Obese patients have increased complications after total knee arthroplasty (TKA). A body mass index (BMI) cutoff of 40 is frequently used to determine eligibility for TKA. Patients with a BMI40 and extremely large legs which may predispose them to complications are approved for surgery because they fall below this cutoff. Alternatively, patients with truncal obesity and a BMI40 are accepted because they have thin legs. We sought to determine whether BMI or girth should be used to determine eligibility.453 patients who underwent TKA were included. A lower extremity girth (LEG) ratio was calculated dividing the width of the soft tissue envelope by bone width on lateral radiographs. Receiver operator curves were generated to predict 90-day complications.There was no difference in median LEG ratio between patients with or without a complication (P = .08). Receiver operator curves indicated that size of the soft tissue envelope had no utility in predicting complications. There was no correlation between LEG ratio and specific complications such as infection, malalignment, or wound complications. Using a LEG ratio threshold of 4.834, the sensitivity and specificity for predicting complications were 48% and 64%, respectively. The median BMI for patients with no complication was 32.3 and 35 for patients with a complication (P = .07).Complications are not necessarily associated with size of the soft tissue envelope in TKA.Decisions concerning TKA should not be made solely on the size of a patient's leg.Level III (retrospective comparative study).

Extraction of implants because of periprosthetic infection (PJI) following complex revision total knee arthroplasty (rTKA) with extensive instrumentation is a daunting undertaking for surgeon and patient alike. The purpose of the present study was to evaluate whether infections following complex rTKA are better treated with 2-stage exchange or irrigation and debridement (ID) with modular component exchange and antibiotic suppression in terms of infection control, reoperation, and function.We reviewed rTKAs that had been performed for the treatment of PJI from 2005 to 2016. Extensive instrumentation was defined as the presence ≥1 of the following: metaphyseal cones/sleeves, distal femoral replacement, periprosthetic fracture instrumentation, or fully cemented stems measuring75 mm. Cases were categorized according to the initial treatment (ID with antibiotic suppression or initiation of 2-stage exchange).Eighty-seven patients with PJI and extensive instrumentation were identified: 56 patients who were managed with ID with suppression and 31 who were managed with the initiation of 2-stage exchange. The rate of success (defined as no reoperation for infection) was similar for the 2 groups (62.5% the ID group compared with 67.7% for the 2-stage group; p = 0.62). The rate of mortality was also similar (39.3% for the ID group compared with 38.7% for the 2-stage group; p = 0.96). Of the 31 patients in the 2-stage group, 18 (58.1%) underwent reimplantation with a revision replacement. Of those 18 patients, 13 were still infection-free at the time of the most recent follow-up; however, when the analysis was expanded to all 31 patients in the 2-stage group, only 13 (41.9%) both had a successful reimplantation and did not require additional surgery for infection. Nine (29.0%) of the 31 patients in the 2-stage group never underwent the second stage, and 4 (12.9%) of the 31 required arthrodesis at the second stage. In contrast, 35 (62.5%) of the 56 patients in the ID group were successfully managed, without additional surgery for the treatment of infection. At the time of the latest follow-up (mean, 3.2 years; range, 2 to 13 years), more patients in the ID group were ambulatory (76.8% in the ID group compared with 54.8% in the 2-stage group; p = 0.05) and maintained a functional bending knee joint (85.7% in the ID group compared with 45.2% in the 2-stage group; p0.001).In the treatment of periprosthetic infection of rTKA with extensive instrumentation, ID with chronic antibiotic suppression was as effective as 2-stage exchange in terms of preventing reoperation for infection and was more effective in terms of maintaining function. These data apply to rTKA with extensive periarticular instrumentation and should not be extrapolated to primary or simple revision implants.Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

AimsAseptic loosening of the tibial component is a frequent cause of failure in primary total knee arthroplasty (TKA). Management options include an isolated tibial revision or full component revision. A full component revision is frequently selected by surgeons unfamiliar with the existing implant or who simply wish to “start again”. This option adds morbidity compared with an isolated tibial revision. While isolated tibial revision has a lower morbidity, it is technically more challenging due to difficulties with exposure and maintaining prosthetic stability. This study was designed to compare these two reconstructive options.MethodsPatients undergoing revision TKA for isolated aseptic tibial loosening between 2012 and 2017 were identified. Those with revision implants or revised for infection, instability, osteolysis, or femoral component loosening were excluded. A total of 164 patients were included; 88 had an isolated tibial revision and 76 had revision of both components despite only having a loose tibial component. The demographics and clinical and radiological outcomes were recorded.ResultsThe patient demographics were statistically similar in the two cohorts. The median follow-up was 3.5 years (interquartile range (IQR) 1 to 12.5). Supplementary femoral metaphyseal fixation was required in five patients in the full revision cohort. There was a higher incidence of radiological tibial loosening in the full component revision cohort at the final follow-up (8 (10.5%) vs 5 (5.7%); p = 0.269). Three patients in the full component revision cohort developed instability while only one in the isolated tibial cohort did. Three patients in the full revision cohort developed a flexion contracture greater than 5° while none in the isolated tibial cohort did.ConclusionIsolated tibial revision for aseptic tibial loosening has statistically similar clinical and radiological outcomes at a median follow-up of 3.5 years, when compared with full component revision. Substantial bone loss can occur when removing a well-fixed femoral component necessitating a cone or sleeve. Femoral component revision for isolated tibial loosening can frequently be avoided provided adequate ligamentous stability can be obtained. Cite this article: Bone Joint J 2020;102-B(6 Supple A):123–128.

Background Irrigation and debridement is an attractive treatment option for acute perioperative and acute hematogenous periprosthetic hip infections. We ask the following questions: (1) What are the results of a two-stage reimplantation if preceded by debridement, antibiotics, and implant retention (DAIR) compared with two-stage reimplantation without an antecedent DAIR? and (2) Do McPherson Musculoskeletal Infection Society (MSIS) host criteria influence results? Methods A total of 114 patients were treated with two-stage exchange for periprosthetic hip infection. Sixty-five patients were treated initially with a two-stage exchange, whereas 49 patients underwent an antecedent DAIR before a two-stage exchange. Patients were classified based on MSIS host criteria. Demographics demonstrated homogeneity between cohorts. Failure was defined as return to the operating room for infection, draining sinus, or systemic infection. Results Treatment failure occurred in 42.9% (21 of 49) of patients treated with an antecedent DAIR. In contrast, treatment failure occurred in only 12.3% (8 of 65) of two-stage only procedures (P < .001). Relative risk of return to the operating room after a two-stage reimplantation with an antecedent DAIR compared with initial resection was 4.52 (95% confidence interval: 1.71, 11.9). MSIS host grading was similar between groups and did not influence the rate of failure in a regression model. The DAIR cohort was also found to consume more resources in terms of hospitalization length and operative procedures (P < .001). Conclusions Two-stage exchange procedures for prosthetic hip infections have a higher failure rate and consume more health-care resources when preceded by a failed DAIR. Surgeons and patients should be aware that a failed DAIR may compromise the results of future two-stage procedures.

Background Two-stage exchange for periprosthetic joint infection (PJI) in total knee arthroplasty (TKA) remains the gold standard treatment in North America. Occasionally, patients with knee PJI are referred for definitive management after resection and antibiotic spacer placement. Currently, little literature exists to suggest how these patients should be managed. The purpose of this study is to report the clinical outcomes of these patients. Methods We retrospectively identified 54 patients (54 knees) from 2000 to 2012 treated for PJI with initial TKA resection and spacer placement performed somewhere other than the definitive treatment center. The mean age at reimplantation was 64 years, with 59% being male. Redebridement and antibiotic spacer exchange was performed for all patients. Mean follow-up was 6.5 years. Results Of the 54 knees, 22 (41%) grew an organism from a culture taken at the time of redebridement and spacer exchange. The most common organism identified at redebridement was Staphylococcus aureus (41%). Obtaining positive cultures at redebridement was not associated with presenting erythrocyte sedimentation rate (P = .46), C-reactive protein (P = .57), or the presence of retained cement (P = .13). Forty-nine of 54 (91%) knees were ultimately reimplanted. Two-year survivorship free of infection in reimplanted knees was 98%. Conclusion Patients referred with an antibiotic knee spacer for PJI have a high rate of positive cultures at the time of redebridement. Neither the presenting serology nor the identification of retained cement was associated with obtaining positive cultures at the time of redebridement. Nevertheless, this unique cohort of patients has favorable outcomes when redebrided with spacer exchange prior to reimplantation.

In an era of innovation in surgical approaches for total hip arthroplasty (THA), there is concern for increasing trends of early failure. The purpose of this study is to evaluate the incidence of early failure of primary THA stratified by surgical approach.A retrospective review was performed on consecutive primary THAs completed from 2007 to 2014 at a high-volume center. THAs were stratified by surgical approach. Only the direct anterior (DAA) and posterior approaches (PA) were included. The primary outcome measure was early revision (5 years). Descriptive statistics were performed using SAS software.In total, 6894 primary THAs performed between 2007 and 2014 were included. Across 2431 DAA THAs and 4463 PA THAs, there were 103 revisions overall. There was no difference in the overall revision rate for DAA THAs (1.69%) compared to PA THAs (1.39%) (P = .33). The DAA had a higher rate of early revisions for femoral component loosening compared to the PA (P = .0003). About 35.7% of DAA THAs were revised for femoral loosening compared to 8% for the PA (P = .0003). Early failure by femoral loosening occurred more often via the DAA in Dorr A bone (P = .03). The PA had a higher incidence of revision for instability (P = .04). There was no difference in modes of failure with regards to time to failure, acetabular loosening, early periprosthetic fracture, or infection.The DAA had a higher incidence of femoral loosening while PA had a higher mode of failure due to instability. Overall revision rates were not statistically different between approaches.

BACKGROUND The purpose of this study is to analyze whether the cost for ceramic-on-polyethylene (C-PE) and ceramic-on-ceramic (COC) bearings used in primary total hip arthroplasty (THA) was changing over time, and if the cost differential between ceramic bearings and metal-on-polyethylene (M-PE) bearings was approaching the previously published tipping point for cost-effectiveness of $325. METHODS A total of 245,077 elderly Medicare patients (65+) who underwent primary THA between 2010 and 2015 were identified from the United States Medicare 100% national administrative hospital claims database. The inpatient hospital cost, calculated using cost-to-charge ratios, and hospital payment were analyzed. The differential cost of C-PE and COC bearings, compared to M-PE, were evaluated using parametric and nonparametric models. RESULTS After adjustment for patient and clinical factors, and the year of surgery, the mean hospital cost and payments for primary THA with a C-PE or COC was within ±1% of the cost for primary THA with M-PE bearings (P < .001). From the nonparametric analysis, the median hospital cost was $318-$360 more for C-PE and COC than M-PE. The differential in median Medicare payment for THA with ceramic bearings compared to M-PE was

BackgroundTwo-stage reimplantation arthroplasty is a commonly used approach for treating chronic periprosthetic joint infections. A prereimplantation threshold value of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) to determine infection eradication and the proper timing

Consensus regarding femoral stem fixation options in revision total knee arthroplasty remains controversial. Tapered, modular, fluted titanium (TMFT) stems have an excellent track record in total hip arthroplasty for their ability to provide axial and rotational stability in situations of compromised host bone. We present 3 successfully treated cases in which the Food & Drug Administration granted permission to use custom TMFT stems in situations of failed femoral fixation in multiple revised knees. These stems hold promise to achieve stable fixation in revision total knee arthroplasty where host metadiaphyseal bone is deficient. Implant manufactures should consider dedicating future resources to create adapters that can link existing successful TMFT stems currently used in hip arthroplasty to revision total knee components when host bone is severely compromised.

Background One-stage protocols for the management of periprosthetic infection take an extended period of time requiring two separate preps and sets of instruments to ensure optimal sterility. While intraoperative service time is one part of the reimbursement algorithm, reimbursement has lagged behind for single-stage treatment with respect to the time and resources necessary to perform these complex treatment regimens. If one-stage results are shown to be acceptable, but not reimbursed appropriately, surgeons will be discouraged from managing periprosthetic joint infection (PJI) in a one-stage fashion. Methods The reimbursement and operative time for 50 PJI procedures were compared with 250 primary total hips and 250 primary total knees by the same 4 surgeons. Results The average reimbursement for a one-stage knee procedure was $2,597.08, with an average intraoperative service time of 259 minutes ($601.60/h). The average reimbursement for a primary total knee was $2,435.00, with an average intraoperative service time of 100 minutes ($1,461/h). The average reimbursement for a one-stage hip procedure was $2,826.17, with an average intraoperative service time of 311 minutes ($545.24/h). The average reimbursement for a primary total hip was $2,754.71 with an average intraoperative service time of 104 minutes ($1,589.26/h). Conclusion One-stage procedures for PJI are reimbursed at approximately 1/3 the hourly rate of a primary procedure, which may discourage surgeons from selecting this treatment alternative even if recent studies confirm efficacy. Payers should be encouraged to reimburse physicians commensurate with the intraoperative service time needed to perform a one-stage procedure as adoption will decrease morbidity and save the healthcare system financially.

Background Mechanical complications have been underemphasized in reports on total knee arthroplasty (TKA) in obese patients. Noticing an increased prevalence of varus collapse of the tibia in obese total knee patients, we sought to determine if variability in proximal tibial cancellous bone strength played a role in failure. We attempted to define a cancellous threshold above which alternative methods of fixation should be used. Methods One thousand one hundred six revision TKAs from 2004-2014 identified 35 patients with varus collapse of the tibia, defined as a change in component position of >10°. Variables analyzed included weight, alignment, component size, and proximal tibial bone stress. Postoperative alignment was compared with prerevision alignment. To calculate tibial stress the following formula was used: mass (kg) × acceleration of gravity (9.8 m/s 2 )/tibial surface area (mm 2 ) = pascals or N/M 2 . Results Twenty-nine of 35 patients weighed >200 lbs, whereas 17 of 35 patients weighed >250 lbs (range 130-354 lbs). Average body mass index was 40.5 kg/m 2 (range 24-61 kg/m 2 ). Twenty-seven of 35 failed tibial components were in the lower half of the manufacturer's tibial size offering. Postsurgical alignment averaged 4.9° valgus (range 2° varus-7° valgus) and collapsed an average of 14.9° (range 10°-22°) before revision. Proximal tibial bone stress averaged 334,324 Pascals (range 188,524-601,416). Twenty-five of 35 patients had proximal tibial bone stress >300,000 Pascals. Conclusion Despite good initial primary TKA alignment, we report catastrophic varus collapse of tibial components in obese patients with small tibial components. When a cancellous threshold of 300,000 Pascals is exceeded, strong consideration should be given to either optimizing the patient's weight or using a longer tibial stem to dissipate forces on proximal tibia.

The Knee Society Score (KSS) instrument is one of the most commonly reported primary outcome measures for total knee arthroplasty (TKA). Originally developed in 1989, the KSS was expanded and updated in 2011; however, the original KSS does not directly translate into the 2011 KSS. To date, no conversion algorithm has been developed, hindering the ability of researchers to adopt the 2011 KSS while maintaining their historical/longitudinal original KSS data. The purpose of this study is to develop regression equations to map the original KSS to the 2011 KSS, allowing original and 2011 KSS data sets to be combined. In this multicenter, nonrandomized study, a convenience sample of 815 patients undergoing primary TKA completed the original KSS questionnaire and the 2011 KSS questionnaire. Additionally, patient gender, patient age, and patient ethnicity were recorded. These data were then used to generate regression models to estimate the 2011 objective and function KSS from the original KSS. Of the 815 study patients, 476 (58%) were female and 339 (42%) were male at an average age of 67 years (SD 9.4). Roughly half of patients were assessed preoperatively (430 of 815 [53%]) with the remaining patients assessed postoperatively (386 of 815 [47%]). The average followup for postoperative patients was 4.4 years (SD 3.5 years). We have created a spreadsheet that can be used by individuals with no statistical training to crosswalk the objective and function subscores from the original KSS to the 2011 KSS [Supplemental materials are available with the online version of CORR®.]. The predictive model very accurately estimated the 2011 objective score, on average, within 0.22 points on the 100-point 2011 objective KSS at the cohort or aggregate level. The objective model accurately estimated the 2011 objective KSS within 8.83 points, on average, of the actual 2011 objective KSS at the individual patient level. However, as a result of large outliers, 37% of the estimated 2011 objective KSS were greater than 10 points from the actual 2011 objective KSS. To illustrate, if you use the model to estimate the 2011 objective KSS on a cohort of 100 patients, a patient with an original objective KSS of 88 will have an estimated objective KSS between 79 and 97 points. On the other hand, if you calculate an average original objective KSS of 88 for all 100 patients, the estimated average 2011 objective KSS will be 88 for the group. The predictive model accurately estimated the 2011 function KSS within 0.14 points on the 1000-point 2011 function KSS at the cohort level. At the patient level, the 2011 function KSS was also estimated within 8.8 points of the actual 2011 function KSS. However, 43% of the estimated function scores were greater than 10 points of the actual 2011 function KSS. Clinicians and researchers can input their original KSS with demographic data into these equations to estimate the 2011 KSS objective and function scores. The small prediction error of 0.22 points that we calculated indicates that these models can be used to estimate the 2011 objective and function KSS at the aggregated cohort level. Although the average error score was within 10 points at the individual patient level, there was a high percentage of large errors resulting from outliers in the data set. These outliers seemed to be related to patients with excellent range of motion who had substantial pain and limited function or patients who have poor range of motion with excellent function and little pain. This may be inherent with the KSS or with the study sample. Nevertheless, one must use caution when estimating at the patient level. Additionally, the accuracy of the prediction scores decreases if any of the demographic variables included in this study are not available.

Total knee arthroplasty occasionally does not meet expectations. This randomized clinical trial assessed the effect of restoration of the native patellofemoral height on clinical outcomes. Group I underwent standard patellar bone resection; group II underwent modified patellar bone resection that adjusted the amount of anterior condylar bone removed and the anterior flange thickness. There were no differences in anterior knee pain, Western Ontario and McMaster Universities Arthritis Index scores, or Knee Injury and Osteoarthritis Outcome Score scores. Patellofemoral compartment height restoration versus patellar height alone does not appear to significantly reduce pain or improve function.