Analysis of the incidence and risk factors of blood transfusion in total knee revision: a retrospective nationwide inpatient sample database study

OBJECTIVE

This study sought to determine the incidence and risk factors of blood transfusion among patients undergoing total knee revision (TKR) using a nationwide database.

METHODS

A retrospective data analysis was conducted based on the Nationwide Inpatient Sample (NIS), enrolling patients who underwent TKR from 2010 to 2019 with complete information. The patients were divided into two groups based on whether they received blood transfusion or not. The demographic characteristics (race, sex, and age), length of stay (LOS), total charge of hospitalization, hospital characteristics (admission type, insurance type, bed size, teaching status, location, and region of hospital), hospital mortality, comorbidities, and perioperative complications were analyzed. Finally, we conducted univariate and multivariate logistic regression to identify factors that were associated with TKR patients to require blood transfusion.

RESULTS

The NIS database included 115,072 patients who underwent TKR. Among them, 14,899 patients received blood transfusion, and the incidence of blood transfusion was 13.0%. There was a dramatic decrease in the incidence over the years from 2010 to 2019, dropping from 20.4 to 6.5%. TKR patients requiring transfusions had experienced longer LOS, incurred higher total medical expenses, utilized Medicare more frequently, and had increased in-hospital mortality rates (all P < 0.001). Independent predictors for blood transfusion included advanced age, female gender, iron-deficiency anemia, rheumatoid disease, chronic blood loss anemia, congestive heart failure, coagulopathy, uncomplicated diabetes, lymphoma, fluid and electrolyte disorders, metastatic carcinoma, other neurological diseases, paralysis, peripheral vascular disorders, pulmonary circulation disorders, renal failure, valvular disease, and weight loss. In addition, risk factors for transfusion in TKR surgery included sepsis, acute myocardial infarction, deep vein thrombosis, pulmonary embolism, gastrointestinal bleeding, heart failure, renal insufficiency, pneumonia, wound infection, lower limb nerve injury, hemorrhage/seroma/hematoma, wound rupture/non healing, urinary tract infection, acute renal failure, and postoperative delirium.

CONCLUSIONS

Our findings highlight the importance of recognizing the risk factors of blood transfusion in TKR to reduce the occurrence of adverse events.

Porous metal block based on topology optimization to treat distal femoral bone defect in total knee revision

Metal block augmentations are common solutions in treating bone defects of total knee revision. However, the stress shielding and poor osteointegration resulted from metal block application could not be neglected in bone defects restoration. In this study, a novel porous metal block was designed with topology optimization to improve biomechanical performance. The biomechanical difference of the topologically optimized block, solid Ti6Al4V block, and porous Ti6Al4V block in treating bone defects of total knee revision was compared by finite element analysis. The inhomogeneous femoral model was created according to the computed tomography data. Combined with porous structures, minimum compliance topology optimization subjected to the volume fraction constraint was utilized for the redesign of the metal block. The region of interest was defined as a 10 mm area of the distal femur beneath the contacting surface. The biomechanical performance of daily motions was investigated. The von Mises stress, the strain energy density of the region of interest, and the von Mises stress of metal blocks were recorded. The results were analyzed in SPSS. In terms of the region of interest, the maximum von Mises stress of the topological optimized group increased obviously, and its average stress was significantly higher than that of the other groups (p < 0.05). Moreover, the topologically optimized block group had the highest maximum strain energy density of the three groups, and the lowest maximum stress of block was also found in this group. In this study, the stress shielding reduction and stress transfer capability were found obviously improved through topology optimization. Therefore, the topological optimized porous block is recommended in treating bone defects of total knee revision. Meanwhile, this study also provided a novel approach for mechanical optimization in block designing.

Spacer exchange in persistent periprosthetic joint infection: microbiological evaluation and survivorship analysis

PURPOSE

The purposes of this study were to determine demographics and characteristics of patients who underwent spacer exchange for persistent infection in the setting of two-stage arthroplasty for periprosthetic joint infection, to describe the microbiology of pathogens involved, to analyze survivorship free from infection in these patients.

METHODS

The institutional prospectively collected database was reviewed to enroll patients with minimum 2 years follow-up. Patients who underwent two-stage procedure for septic arthritis were excluded, as were patients who had spacer fracture or dislocation.

RESULTS

A total of 34 patients (41 procedures) were included. Mean age was 65.0 ± 12.8 years. Mean follow-up was 53.4 ± 24.8 months. Mean number of previous procedures was 3.6 ± 1.2. A total of 27 (79.4%) patients underwent final reimplantation. The most frequently isolated pathogen in spacer exchange was Staphylococcus epidermidis (10 cases, 28.6%). Polymicrobial cultures were obtained from 9 (25.71%) patients, 10 (28.6%) presented culture-negative infections. A total of 11 (32.4%) resistant pathogens were isolated, and 16 (47.0%) difficult to treat pathogens were detected. Eradication rate was 78.8%. Overall survivorship of implants after final reimplantation was 72.8% at 51.8 months.

CONCLUSION

Surgeons should be aware that subjects necessitating spacer exchange often present multiple comorbidities, previous staged revision failures, soft-tissue impairment and difficult to treat infection. In these patients, spacer exchange provides good clinical results and infection eradication, preventing arthrodesis or amputation.

Medium term clinical outcomes of tibial cones in revision knee arthroplasty

INTRODUCTION

Trabecular metal cones are a relatively new option for reconstruction of major bone defects during revision total knee arthroplasty (TKA). The purpose of the present study was to retrospectively assess medium-term results for tibial cones in revision TKA with a severe proximal tibial bone defect. We hypothesized that revision TKA patients with bone defects treated with trabecular metal cones have excellent medium-term clinical and radiological results.

PATIENTS AND METHODS

A single-center retrospective review included all consecutive cases of tibial revision using trabecular metal cones. All patients with a minimum 2-year follow-up were included in the study. There were no exclusion criteria. The primary endpoint was tibial cone survivorship. The secondary endpoints were revision TKA all-cause survivorship, patient-reported outcome measures with a Knee injury and Osteoarthritis Outcome Score (KOOS), SF 12, and radiographic analysis.

RESULTS

Five of the 57 patients alive at last follow-up (8.77%) had undergone revision (4 for infection and 1 for instability). Complications comprised four cases (7.02%) of infection, 2 cases (3.51%) of tibial and femoral implant aseptic loosening that did not require revision surgery, 1 of which (1.75%) with associated patellar loosening, and 1 case (1.75%) of instability. Kaplan-Meier estimates showed 100% 5-year survivorship with tibial cone revision for aseptic loosening and 93.44% (95% CI 83.47-97.49%) for all-cause revision.

DISCUSSION

The present study of cones used for tibial revision supports shows excellent results; however, longer and larger follow-up is needed to better assess results in revision TKA.

LEVEL OF EVIDENCE

4, retrospective study.

Localized cytokine responses to total knee arthroplasty and total knee revision complications

Background

The study of localized immune-related factors has proven beneficial for a variety of conditions, and one area of interest in the field of orthopaedics is the impact of implants and localized infections on immune response. Several cytokines have shown increased systemic concentrations (in serum/plasma) in response to implants and infection, but tissue-level cytokines have not been investigated as thoroughly.

Methods

This exploratory study investigated tissue-level cytokines in a cohort of patients (N = 17) in response to total knee arthroplasty and total knee revision to better understand the immune response to implants and localized infection (e.g., prosthetic joint infection). The overall goal of this study was to provide insight into the localized cytokine response of tissues and identify tissue-level markers specific to inflammation caused by implants vs. inflammation caused by infection. Tissues were collected across several anatomical locations and assayed with a panel of 20 human inflammatory cytokines to understand spatial differences in cytokine levels.

Results

In this study, six cytokines were elevated in implanted joints, as compared to native joints: IL-10, IL-12p70, IL-13, IL-17A, IL-4, and TNF-α (p < 0.05). Seven cytokines showed infection-dependent increases in localized tissues: IL-1α, IL-1β, IL-6, IL-8, MCP-1, MIP-1α, and MIP-1β (p < 0.05).

Conclusions

This study demonstrated that differences exist in tissue-level cytokines in response to presence of implant, and some cytokines were specifically elevated for infection; these responses may be informative of overall tissue health. These results highlight the utility of investigating localized cytokine concentrations to offer novel insights for total knee arthroplasty and total knee revision procedures, as well as their complications. Ultimately, this information could provide additional, quantitative measurements of tissue to aid clinical decision making and patient treatment options.

The proper timing of second-stage revision in treating periprosthetic knee infection: reliable indicators and risk factors

Background

Two-stage revision is the standard procedure for periprosthetic knee infection. But when to perform the second-stage is still under debate. We attempt to search the reliable indicators, risk factors, and proper timing for the second-stage revision.

Methods

We reviewed and followed 81 infected total knee arthroplasty patients who underwent two-stage revision from January 2010 to January 2014. Our cohort included 56 males and 25 females, all patients were confirmed as PJI with the same phenotypic cultures. The average age was 64.8 ± 8.21 (range 36–78) months. The mean follow-up time was 46.5 ± 17.6 (range 12–72) months after the second-stage surgeries. The diagnostic parameters including serum C-reaction protein, erythrocyte sedimentation rate, and intraoperative frozen section at the time of re-implantation were analyzed. The spacer detention time and antibiotic treatment time were compared.

Results

Ten of them went through failed first- or second-stage surgeries. The overall success rate was 87.7%. The intraoperative frozen section is a good indicator at the time of re-implantation; the sensitivity and specificity is 90 and 83.1%. Serum CRP and ESR showed poor diagnostic value at time of re-implantation. Atypical pathogen infection, positive FS, and previous sinus were high-risk factors for failure of two-stage revision. Spacer detention time between 12 and 16 weeks had higher success rate than over 16 weeks.

Conclusion

The proper timing of re-implantation should be combined with disappearance of clinical symptoms and negative intraoperative FS with spacer detention time at 12 to 16 weeks.

Revision total knee arthroplasty with porous-coated metaphyseal sleeves provides radiographic ingrowth and stable fixation

PURPOSE

Porous-coated metaphyseal sleeves are designed to fill bone defects and facilitate osseointegration when bone loss in encountered during revision total knee arthroplasty (TKA). The purpose of this study is to evaluate short-term results of porous-coated metaphyseal sleeves with regards to implant fixation and clinical outcomes.

METHODS

A retrospective review was conducted on 50 patients (79 sleeves-49 tibial and 30 femoral) who had a press-fit metaphyseal sleeve with revision TKA. Tibial and femoral bone loss was classified according to the Anderson Orthopaedic Research Institute (AORI) bone defect classification. Post-operative complications of infection, revision surgery, and dislocation were assessed. Follow-up radiographs were evaluated for signs of loosening using the criteria developed by the Knee Society. The median follow-up was 58.8 months (range 25.8-93.0 months).

RESULTS

The bone loss classifications were 1 type 1, 30 type 2a, 2 type 2b, and 17 type 3, and with regards to the femur, 5 were type 1, 8 type 2a, 31 type 2b, and 6 type 3. At final follow-up, 41/45 (91.1%) tibial and 28/29 (96.6%) femoral sleeves showed radiographic evidence of ingrowth. Of these 69 patients, all showed radiographic evidence of bony ingrowth. Three sleeves were revised for infection and two for loosening. The re-operation rate for loosening was 5/74 (6.8%) and for any reason was 14/74 (18.9%).

CONCLUSIONS

Modular porous-coated press fit metaphyseal sleeves fill defects and provide evidence of radiographic ingrowth. Short-term stable fixation can be achieved with sleeves, which is helpful as more patients undergo revision total knee arthroplasty with greater bone loss. Longer duration studies are needed to ascertain the survival rate of these implants.

LEVEL OF EVIDENCE

IV.

Simultaneous posterior dislocation of primary total knee arthroplasty with ipsilateral tibial shaft fracture: A case report and review of literature

Dislocation following total knee arthroplasty (TKA) is a rare but serious complication. Here, a 74-year-old woman with posterior dislocation of her right cruciate-retaining TKA and ipsilateral tibia diaphysis fracture was presented. She only slipped down on the ground with a quick twist of her right leg. She underwent revision semiconstrained TKA and osteosynthesis of tibial fracture with plate and screw. Her partially avulsed patellar tendon was repaired as well. She was ambulatory with a cane and satisfied with revision operation at last control. Extensor mechanism and functional posterior cruciate ligament is especially important in patients receiving cruciate-retaining TKA. As far as we know, simultaneous dislocation of TKA with fracture of tibia diaphysis has never been reported before.

Joint line position in revision total knee arthroplasty: the role of posterior femoral off-set stems

BACKGROUND

Elevation of the joint line frequently occurs in revision total knee arthroplasty (RTKA) because of a wider flexion space than extension space. One solution to balance this flexion-extension space involves the introduction of couplers between the stem and femoral components, and the use of posteriorly offset femoral stems that we hypothesized would improve gap balancing and facilitate joint line restoration.

METHODS

We retrospectively reviewed a selected series of 43 RTKA. Postoperative joint line height was subtracted from intended height using postoperative lateral radiographs. The value was negative if the joint line position was lowered, and positive if raised.

RESULTS

Forty knees were followed for a mean of 3.5years. Mean postoperative joint line position change from intended position was 1.5mm (range -2.5-7.5mm). In 28 knees (70%), the joint line position was restored to within ±2mm of the intended position; in eight knees (20%), from 2-4mm; and in four knees (10%), >4mm. Joint line position was raised in 32 knees (80%) and lowered in eight (20%). In the offset stem knees, the intended joint line position was 0.9mm (range -1.2-3.4mm) as compared with 3.2mm (range -2.5-7.5mm) for the straight stem knees.

CONCLUSIONS

A coupler system between the femoral stem and femoral component restored the joint line in 70% of cases. The posterior offset stem provided increased posterior condylar offset, addressed the wider flexion space, provided better positioning of the stem, and restored the joint line.

LEVEL OF EVIDENCE

Therapeutic Study Level IV.