Antibiotic cement was associated with half the risk of re-revision in 1,154 aseptic revision total knee arthroplasties

A systematic review and meta-analysis of antibiotic-loaded bone cement for prevention of deep surgical site infections following primary total joint replacement

BACKGROUND

The use of antibiotic-loaded bone cement (ALBC) as a mean for preventing deep surgical site infections (SSI) after total joint replacement is controversial. Therefore, we have conducted a meta-analysis to evaluate the prophylactic effect of ALBC for SSI prevention in patients undergoing arthroplasty. This study was conducted to revise treatment guidelines for MRSA infections in Japan.

METHODS

PubMed (Medline), Scopus, Embase, Web of Science and Cochrane library were searched for relevant articles comparing preventive effect of ALBC for patients undergoing primary total joint arthroplasty by August 2022. Primary outcome was the incidence of deep SSI. Subgroup analyses by type of surgery (total hip (THA) or knee (TKA) arthroplasty) and by causative pathogen (methicillin-resistant Staphylococcus aureus (MRSA)) were performed.

RESULTS

Of the 3379 studies identified for screening, six studies involving 5745 patients were included. The use of ALBC significantly reduced the incidence of deep SSI in overall patients (risk ratio [RR] 0.60, 95% confidential interval [CI] 0.39-0.92), but the evidence level was very low. There was no significant preventive effect for ALBC compared with non-ALBC in both THA and TKA (THA, RR 0.52, 95% CI 0.23-1.16; TKA, RR 0.64, 95% CI 0.38-1.06), and for preventing MRSA-SSI (RR 0.27, 95% CI 0.03-2.41).

CONCLUSIONS

Although the overall preventive effect of ALBC was significant, the evidence level was very low. Thus, the routine use of ALBC as a mean to prevent SSI in arthroplasty may not be suggested.

Cement loaded with high-dose gentamicin and clindamycin does not reduce the risk of subsequent infection after aseptic total hip or knee revision arthroplasty: a preliminary study

PURPOSE

The aim of this study was to quantify the prophylactic effect of high-dose gentamicin and clindamycin antibiotic-loaded bone cement (ALBC) during revision total hip (rTHA) or knee (rTKA) arthroplasty for aseptic reasons. The hypothesis was that the raw surgical site infection (SSI) rate is lower when this particular cement is used in comparison with cement loaded with standard-dose gentamicin during rTHA or rTKA for aseptic reasons.

METHODS

This retrospective study included 290 consecutive patients undergoing aseptic rTHA or rTKA. Two consecutive cohorts were defined: the first (control group) involved 145 patients where ALBC with gentamicin only was used; the second (study group) involved 145 patients where ALBC with high-dose gentamicin and clindamycin was used. The primary endpoint was the raw SSI rate after 24 months.

RESULTS

The raw SSI rate was 8/145 (6%) in the control group and 13/145 (9%) in the study group (odds ratio 0.62, p = 0.26). There was a significant impact of the presence of any risk factor on the SSI rate (15/100 versus 6/169, odds ratio = 4.25, p = 0.002), but no significant impact of any individual risk factor. No complication or side effect related to ALBC was observed in either group.

CONCLUSION

These results do not support the routine use of gentamicin and clindamycin ALBC for fixation of revision implants after rTHA and rTKA for aseptic reasons.

Bone Cement in Adult Hip and Knee Reconstruction: A Review of Commercially Available Options and Clinical Outcomes

Polymethyl-methacrylate (PMMA) bone cement is used extensively in hip and knee arthroplasty. A thorough understanding of the basic chemistry underlying PMMA is important for orthopaedic surgeons because this underscores the specific way bone cement is used during surgery. Recently, clinical research has shed light on the various types of PMMA regarding the viscosity of the mixture and the effect of cement additives. These variations in composition may alter the clinical efficacy of implanted bone cement in hip and knee arthroplasty. Understanding these key differences will allow the surgeon to tailor the PMMA composition as needed to maximize outcomes of hip and knee arthroplasty. This review will summarize the preclinical feature of PMMA, evaluate current and past commercially available bone cement options, analyze preclinical results and clinical outcomes of various bone cement types, and highlight future areas of research.

Patient-relevant outcomes following elective, aseptic revision knee arthroplasty: a systematic review

BACKGROUND

The aim of this systematic review was to summarise the evidence for the clinical effectiveness of revision knee arthroplasty (rKA) compared to non-operative treatment for the management of patients with elective, aseptic causes for a failed knee arthroplasty.

METHODS

MEDLINE, Embase, AMED and PsychINFO were searched from inception to 1st December 2020 for studies on patients considering elective, aseptic rKA. Patient-relevant outcomes (PROs) were defined as implant survivorship, joint function, quality of life (QoL), complications and hospital admission impact.

RESULTS

No studies compared elective, aseptic rKA to non-operative management. Forty uncontrolled studies reported on PROs following elective, aseptic rKA (434434 rKA). Pooled estimates for implant survivorship were: 95.5% (95% CI 93.2-97.7%) at 1 year [seven studies (5524 rKA)], 90.8% (95% CI 87.6-94.0%) at 5 years [13 studies (5754 rKA)], 87.4% (95% CI 81.7-93.1%) at 10 years [nine studies (2188 rKA)], and 83.2% (95% CI 76.7-89.7%) at 15 years [two studies (452 rKA)]. Twelve studies (2382 rKA) reported joint function and/or QoL: all found large improvements from baseline to follow-up. Mortality rates were low (0.16% to 2% within 1 year) [four studies (353064 rKA)]. Post-operative complications were common (9.1 to 37.2% at 90 days).

CONCLUSION

Higher-quality evidence is needed to support patients with decision-making in elective, aseptic rKA. This should include studies comparing operative and non-operative management. Implant survivorship following elective, aseptic rKA was ~ 96% at 1 year, ~ 91% at 5 years and ~ 87% at 10 years. Early complications were common after elective, aseptic rKA and the rates summarised here can be shared with patients during informed consent.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020196922.

Does stem profile have an impact on the failure patterns in revision total knee arthroplasty?

INTRODUCTION

Revision total knee arthroplasty (RTKA) has been increasing continuously. The results of RTKA still remain unsatisfactory. Failure patterns and risk factors in RTKA were thoroughly analyzed, with periprosthetic joint infections (PJI) and aseptic loosening remaining at the forefront of re-revision (ReRTKA) causes. While there is evidence that stem profile impacts the revisability of cemented implants, its association with the modes of RTKA failure is unknown.

METHODS

50 consecutive ReRTKA performed in a single orthopedic center during 2016-2017 were retrospectively analyzed. The cases were stratified according to age, sex, number of preexisting revisions, fixation technique, stem design and causes of re-revision. All explanted implants with conical vs. cylindrical stem profiles were compared.

RESULTS

Mean age was 67 ± 11.5, and 54% were females. 72% of the cases had ≥ 3 previous revisions. 88% were full-cemented, 3% hybrid and 9% press-fit stems. 36% of the RTKA had conical, 58% cylindrical and 6% combined stem profiles. 92% of the RTKA components were removed. Removal causes were: PJI (52.2%), aseptic loosening (34.8%), implant malposition (9.8%), painful knee (1.1%) and instability (2.2%). While the overall RTKA failure patterns were equally distributed between conical and cylindrical stems, subgroup analysis of only cemented ReRTKA revealed a higher incidence of aseptic loosening within cylindrical stem profiles (46.7% vs. 25.7%, P = 0.05).

CONCLUSION

Stem profile may have an impact on the process of aseptic loosening in cemented non-metaphyseal engaging RTKA, with cylindrical designs tending to worse outcomes than conical designs. Large cohort studies could provide more clarity on current observation.

Patients Who Undergo Early Aseptic Revision TKA Within 90 Days of Surgery Have a High Risk of Re-revision and Infection at 2 Years: A Large-database Study

BACKGROUND

Early aseptic revision within 90 days after primary TKA is a devastating complication. The causes, complications, and rerevision risks of aseptic revision TKA performed during this period are poorly described.

QUESTIONS/PURPOSES

(1) What is the likelihood of re-revision within 2 years after early aseptic TKA revision within 90 days compared with that of a control group of patients undergoing primary TKA? (2) What are the indications for early aseptic TKA revision within 90 days? (3) What are the differences in revision risk between different indications for early aseptic revision TKA?

METHODS

Patients who underwent unilateral aseptic revision TKA within 90 days of the index procedure were identified in a national insurance claims database (PearlDiver Technologies) using administrative codes. The exclusion criteria comprised revision for infection, history of bilateral TKA, and age younger than 18 years. The PearlDiver database was selected for its large and geographically diverse patient base and the availability of outpatient follow-up data that are unavailable in other databases focused on inpatient care. A total of 481 patients met criteria for early aseptic revision TKA, with 14% (67) loss to follow-up at 2 years. This final cohort of 414 patients was compared with a control group of patients who underwent primary TKA without revision within 90 days. For the control group, 137,661 patients underwent primary TKA without early revision, with 13% (18,138) loss to follow-up at 2 years. Among these patients, 414 controls were matched using a one-to-one propensity score method; no differences in age, gender, and Charlson comorbidity index score were observed between the groups. Indications for initial revision and 2-year re-revision were recorded. The Kaplan-Meier method was used to assess survival between the early revision and control groups.

RESULTS

Two-year survivorship free from additional revision surgery was lower in the early aseptic revision cohort compared with the control (78% [95% confidence interval 77% to 79%] versus 98% [95% CI 96% to 99%]; p < 0.001). Among early revisions, 10% (43 of 414) of the patients underwent re-revision for periprosthetic infection with an antibiotic spacer within 2 years. The reasons for early aseptic revision TKA were instability/dislocation (37% [153 of 414]), periprosthetic fracture (23% [96 of 414]), aseptic loosening (23% [95 of 414]), pain (11% [45 of 414]), and arthrofibrosis (6% [25 of 414]). Early revision for pain was associated with higher odds of re-revision than early revisions performed for other all other reasons (44% [20 of 45] versus 29% [100 of 344]; odds ratio 2.0 [95% CI 1.0 to 3.7]; p = 0.04).

CONCLUSION

Acute early aseptic revision TKA carries a high risk of re-revision at 2 years and a high risk of subsequent periprosthetic joint infection. Patients who undergo an early revision should be carefully counseled regarding the very high risk of repeat revision and discouraged from having early revision unless the indications are absolutely clear and compelling. Early aseptic revision for pain alone carries an unacceptably high risk of repeat revision and should not be performed. Adjunctive measures for infection prophylaxis should be strongly considered. Specific interventions to reduce surgical complications in this subset of patients have not been adequately studied; additional investigation of strategies to minimize the risk of reoperation or infection is warranted.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Failure Analysis in Multiple TKA Revisions-Periprosthetic Infections Remain Surgeons' Nemesis

BACKGROUND

The aim of this study was to categorize reasons for failure and to analyze the survivorship of multiple total knee arthroplasty (TKA) revisions.

METHODS

The study retrospectively evaluated all multiple TKA revisions performed between 2005 and 2015 at the authors' institutions. Sixty-three patients (35 female, 28 male, age 64 ± 10 years, follow-up 55 ± 36 months) underwent a total of 157 re-revision TKA surgeries (range 2-5). The revision indications were divided up into main diagnoses. Survivorship was evaluated by mixed model analysis.

RESULTS

The main overall reason for re-revision was periprosthetic joint infection (PJI) (48%), followed by instability (12%), polyethylene wear (11%), malpositioning (8%), and aseptic loosening (8%). Survivorship shortened with an increasing number of revision surgeries (p = 0.003). While PJI was in 38% of all cases, the reason for the first revision, incidence increased constantly with the number of revisions (48% at second revision, 55% at third revision, 86% at fourth revision, and 100% at fifth revision, p = 0.022). If periprosthetic infection caused the first revision, patients showed an average of two more septic revisions at follow-up than patients with an aseptic first revision indication (p < 0.001). In 36% of cases, the reason for follow-up surgery in case of periprosthetic infection was again PJI.

CONCLUSION

The probability of survival of the implanted knee arthroplasty is significantly reduced with each subsequent revision. Periprosthetic infection is the main cause of multiple revisions.

Outcomes in revision total knee arthroplasty (Review)

Revision total knee arthroplasty (TKA) is a challenging surgical procedure. Although good results are presented, the outcomes are worse in comparison with those of primary TKA, with a higher failure rate. The main reasons for the failure of revision TKA include: sepsis, loosening and instability. There are multiple variables linked to these results, and it is difficult to determinate the exact cause as it is often a multifactorial issue. These variables may be related to the quality of the index-procedure (TKA), to the revision procedure or to patient characteristics. The purpose of this review was to highlight the outcomes of revision knee arthroplasty and main factors that may influence the results. Considerable progress has been made during the last 30 years regarding infection treatment and prevention, complex revision prosthetic design and surgical technique development. Although the outcomes have improved over time, patients who undergo revision TKA may need further re-operations in the future.

Is Dual Antibiotic-Loaded Bone Cement More Effective and Cost-Efficient Than a Single Antibiotic-Loaded Bone Cement to Reduce the Risk of Prosthetic Joint Infection in Aseptic Revision Knee Arthroplasty?

BACKGROUND

Higher rates of prosthetic joint infections (PJIs) are related to patient risk factors and/or to special surgical procedures such as revision total knee arthroplasty (rTKA). Among the measures discussed to better protect those patients from the higher infection risks use of dual antibiotic-loaded bone cement has emerged as a further prophylactic option.

METHODS

This retrospective study included 246 patients undergoing strictly aseptic revision knee arthroplasty at our institution in the time period 2015-2018. Based on the type of bone cement used for the cementation of the revision prosthesis, 2 groups were defined. In total, 143 patients received the low-dose single antibiotic-loaded bone cement (SALBC) PALACOS R+G and 103 patients received the high-dose dual antibiotic-loaded bone cement (DALBC) COPAL G+C. The number of PJI cases in each group over a follow-up time of minimum 1 year was compared and the extra costs for the DALBC use calculated against the economic savings per each avoided PJI case on basis of 3 different assumptions (treatment costs and amount of cement use).

RESULTS

Use of DALBC in aseptic rTKA was associated with a significant reduction in PJI cases (relative risk = 57%, PJI rate in the SALBC group 4.1% vs 0% in the DALBC group, P = 0.035). The calculated total savings per patient was $1367. Depending on the economic assumptions the range of savings was between $1413 (less favorable calculation model) and $3661 (most favorable calculation model).

CONCLUSION

The use of DALBC in rTKA has been found to be more effective in preventing PJI and proved cost-efficient in all our cost-calculation models.

Why Do Revision Total Knee Arthroplasties Fail? A Single-Center Review of 1632 Revision Total Knees Comparing Historic and Modern Cohorts

BACKGROUND

Utilization of revision total knee arthroplasty (TKA) has been increasing, and reasons for failure are less understood than those of primary TKA. The purpose of this study is to identify the rates and mechanisms of failure of revision TKA, and compare those between a historic (1986-2005) and modern (2006-2015) cohort.

METHODS

All revision TKAs performed at a single institution between 1986 and 2015 were reviewed, with minimum 2-year follow-up. Failure was defined as a second revision surgery in which any component was exchanged. Diagnosis at the time of index and any re-revision procedure was determined.

RESULTS

In total, 1632 revision TKAs in 1560 patients were reviewed. The average age was 65.1 and the average follow-up was 61.4 months. Overall failure rate was 22.8%, with no significant differences between the historic and modern cohort (25.1% vs 22.0%, P = .19). The leading cause for failure was infection in 38.5% of failures. The next most common causes for failure were aseptic loosening (20.9%) and instability (14.2%). Failure rate among revision TKAs for infection was 33%, with 67.2% failing due to repeat infection. Multivariate analysis found that septic index revision (odds ratio [OR] 1.91, 95% confidence interval [CI] 1.47-2.48), male gender (OR 1.41, 95% CI 1.11-1.78), and age less than 65 (OR 1.56, 95% CI 1.23-1.97) were independent risk factors for failure.

CONCLUSION

There remains a high rate of failure in revision TKA, with infection being the most common reason for failure. Rates and primary reasons for failure have not changed significantly in the past decade.

Antibiotics and cement: what I need to know?

We conducted a systematic review about antibiotic-loaded bone cement (ALBC) with a focus on clinical evidence about ALBC in general, concerns about ALBC and ALBC cost.

Antibiotic containing bone cement in prevention of hip and knee prosthetic joint infections: A systematic review and meta-analysis

BACKGROUND

Prosthetic joint infection (PJI) is the most serious total joint arthroplasty (TJA) complication despite several aseptic and antiseptic preventive measures. There is no clear evidence or even consensus, whether antibiotic-loaded bone cement (ALBC) should be used, in addition to systemic short-term routine antibiotic prophylaxis, to reduce the risk of PJI in primary TJA. We aimed to analyze the efficacy of ALBC for prevention of PJI in patients undergoing primary TJA.

METHODS

We searched systematically for randomized controlled trials (RCTs) in PubMed, Scopus, Embase, Web of Science and Cochrane library. Two reviewers independently screened potentially eligible studies according to predefined selection criteria and assessed the risk of bias using a modified version of the Cochrane risk of bias tool. PJI was prespecified as the primary outcome of interest. The meta-analyses were based on risk ratios using random-effects model per default. For the purpose of sensitivity, the corresponding fixed effects model odds ratios were calculated with the use of the Peto method as well. To evaluate a potential difference in effect sizes using different types (subgroups) of antibiotics used in bone cement, and at different follow-up periods, we performed stratified meta-analyses.

RESULTS

Thirty-seven studies were eligible for the systematic review and qualitative synthesis, and 9 trials (6507 total joint arthroplasties) were included in this meta-analysis. Overall ALBC significantly reduced the risk of PJI following primary TJAs (RRs, 0.36; 95% CIs, 0.16 to 0.80; P = 0.01) with a moderate degree of inconsistency (I2 = 47%). Based on stratified meta-analyses the use of gentamicin appeared to have a better effect (P = 0.0005) in the total hip arthroplasty. Pooled data of different antibiotics used in knee arthroplasties showed a significant association of cefuroxime (RRs, 0.08; 95% CIs, 0.01 to 0.63; P = 0.02). Further, ALBCs significantly reduced the PJI at one and two years of follow-up (P = 0.03 and P = 0.005 respectively).

CONCLUSIONS

The evidence suggests that ALBCs are effective in reducing the PJI following primary TJA; i.e. between 20 and 84% reduced risk. However, the clear limitations of the available trial evidence highlight the need for joint-specific confirmatory trials, that will need to be designed as cluster-randomized trials of clinics in countries with well-functioning arthroplasty registries.The translational potential of this article: This meta-analysis highlights the prophylactic potential of ALBCs in lowering the risk of infection following primary hip or knee arthroplasties but emphasizes the need for more recent confirmatory trials.

Antibiotic-Loaded Hydrogel Coating to Reduce Early Postsurgical Infections in Aseptic Hip Revision Surgery: A Retrospective, Matched Case-Control Study

Periprosthetic joint infections (PJIs) are a cause of frequent implant failure in revision hip replacement surgery. The purpose of this study is to evaluate the onset of early postoperative infections in patients who underwent hip surgery with cementless prostheses treated with an antibiotic loaded hydrogel on their surface, in addition to systemic prophylaxis, and compare them to a control group. The secondary objective was to evaluate the onset of any local and systemic adverse effects and interference with bone ingrowth processes and functional recovery. A retrospective observational study was conducted on patients who underwent revision hip surgery by performing a 1:1 match between patients treated with an antibiotic hydrogel (ALH) and the control patients. The incidence of PJIs was assessed with a minimum of six months follow-up. Seventeen patients treated with the ALH were compared with 17 patients from the control group. No PJIs were reported in the ALH group versus the six cases encountered in the control group (p < 0.0001). No significant differences were reported with regard to prosthetic osseointegration and functional results, nor were there side effects in the ALH group. Despite the low sample size, the use of on-site prophylaxis with ALH has proven effective and safe in reducing the risk of PJIs in patients with a high risk for infections. Further studies are needed to validate these results in other implant-related surgeries.

Sagittal profile has a significant impact on the explantability of well-fixed cemented stems in revision knee arthroplasty: a biomechanical comparison study of five established knee implant models

BACKGROUND

Easy revisability is gaining increasingly in importance. The removal of well-fixed cemented stems is very demanding and is often associated with increased operative morbidity. Implant design may be here a decisive impact factor, and the best way to ascertain it is experimentally. Aim of this study is to assess different cemented stems of established knee revision implants in regard to their removal capability.

METHODS

Based on their sagittal profile, five stem extensions from known manufacturers were divided in conical, conical-cylindrical and cylindrical designs. The pedicles were also characterized in respect to their cross section, diameter and surface roughness. The cemented stems were dismounted six times each in a reproducible biomechanical setup. The explantation energy required was determined and statistical analyzed.

RESULTS

The conical shaft needed significantly the slightest explantation energy with 19.2 joules (p = 0.004). There was a strong negative linear correlation between conicity proportion and explantation energy of the cemented stems (R² = 0.983). The removal of the three purely cylindrical shafts-regardless of their differences in diameter, cross-sectional design and surface- was the most demanding (98.3, 105, and 116.7 joules) with only secondary differences between them.

CONCLUSION

The longitudinal stem profile may have a primary impact on the explantability of well-fixed cemented shafts with conical designs showing superiority. Cross-sectional profile and surface roughness had here a less decisive influence on the explantability. Surgeons can choose proper implants and removal techniques depending on potential implant-associated revision risks and re-revisions to be expected.

Is Antibiotic Prophylaxis Cost-effective for Dental Patients Following Total Knee Arthroplasty?

Introduction:

Routine antibiotic prophylaxis (AP) to prevent prosthetic joint infection remains controversial. The lack of prophylaxis guideline consensus from the American Academy of Orthopaedic Surgeons (AAOS) and the American Dental Association (ADA) contributes to clinician confusion.

Objectives:

This cost-effectiveness decision model informs the AP debate and guideline development by comparing the benefits, harms, and costs of alternative prophylaxis strategies.

Methods:

A Markov state-transition model was developed comparing lifetime health outcomes and costs of alternative AP strategies for dental patients aged 65 y with a history of total knee arthroplasty (TKA). Based on our interpretation of AP recommendations from the AAOS and ADA, incremental cost-effectiveness ratios were calculated to compare the following strategies: no AP, AP for the first 2 y after a TKA, and lifetime AP.

Results:

The no-AP strategy had the lowest average lifetime costs ($17,119) and quality-adjusted life years (11.2151). Compared with a no-prophylaxis strategy, the 2-y AP strategy had incremental costs of $56 and 0.0006 QALYs gained and was cost-effective (incremental cost-effectiveness ratio = $95,100) when a willingness-to-pay threshold of $100,000 per quality-adjusted life year was used. Based on the results of 1-way sensitivity analysis, the no-AP strategy was cost-effective when we modestly increased base case amoxicillin adverse event estimates that were substantially lower than estimates reported in previous models. When plausible combinations of important model parameters were varied, model results suggested that there may be clinical scenarios when AP may be appropriate for some medically at-risk patient populations.

Conclusion:

The results of cost-effectiveness decision modeling generally support questioning routine AP for dental patients with TKA. Sensitivity analyses suggest that prophylaxis may be cost-effective for patient populations with a higher medical risk of infection. This finding is consistent with the recommendations of the 2015 ADA practice guideline and the appropriate use criteria jointly developed by the AAOS and the ADA.

Knowledge Transfer Statement:

The results of this decision modeling research support the contention that routine AP before invasive dental procedures to prevent prosthetic joint infection may not be cost-effective for patients without medical conditions, potentially conferring a higher infection risk. Model sensitivity analyses suggest that there may be clinical situations when medically at-risk patients benefit from AP.

Antibiotic-laden Bone Cement in Primary and Revision Hip and Knee Arthroplasty

Antibiotic-laden bone cement (ALBC) has a number of different uses in primary and revision total joint arthroplasty. However, considerable controversy remains regarding how and when it is best used. The prophylactic use of low-dose ALBC in primary cemented total hip arthroplasty is well supported by the literature, conferring both clinical and economic benefits. In contrast, conclusive evidence on the clinical efficacy or economic benefit of the routine use of ALBC in primary total knee arthroplasty remains elusive. Given the currently available evidence, we cannot determine definitively whether the routine use of ALBC in primary total knee arthroplasty is justified, although selective use in patients with a high risk of infection seems warranted. The routine use of ALBC in revision total joint arthroplasty is well accepted, with good supporting evidence in studies of both aseptic and first-stage revision procedures. Although limited clinical evidence exists on the use of ALBC at the time of definitive component reimplantation after septic revision, the rationale for its use is strong.

Antibiotic bone cement’s effect on infection rates in primary and revision total knee arthroplasties

AIM

To compare infection rates in primary and revision total knee arthroplasty (TKA) procedures using antibiotic impregnated bone cement (AIBC) to those rates in procedures not using AIBC.

METHODS

A systematic review and meta-analysis was conducted in search for randomized controlled trials/studies (RCTs) pertaining to the field of antibiotic AIBC vs non-AIBC groups in both primary and revision TKA procedures. The primary literature search performed was to identify all RCTs that assessed AIBC in primary and revision TKA procedures. This search was done strictly through the PubMed database using the article “filters” setting that identified and separated all RCTs from the overall search. The original search was “Primary/revision total knee arthroplasty using AIBC”. Other key terms and phrases were included in the search as well. Eligible articles that were used in the “results” of this review met the following criteria: (1) Involved primary or revision TKA procedures (for any reason); (2) included TKA outcome infection rate information; (3) analyzed an AIBC group vs a non-AIBC control group; (4) were found through the RCT filter or hand search in PubMed; and (5) published 1985-2017. Exclusion criteria was as follows: (1) Patients that were not undergoing primary or revision TKA procedures; (2) articles that did not separate total hip arthroplasity (THA) vs TKA results if both hip and knee revisions were evaluated; (3) papers that did not follow up on clinical outcomes of the procedure; (4) extrapolation of data was not possible given published results; (5) knee revisions not done on human patients; (6) studies that were strictly done on THAs; (7) articles that were not found through the RCT filter or through hand search in PubMed; (8) articles that did not evaluate AIBC used in a prosthesis or a spacer during revision; (9) articles that did not compare an AIBC group vs a non-AIBC control group; and (10) articles that were published before 1985.

RESULTS

In total, 11 articles were deemed eligible for this analysis. Nine of the 11 studies dealt with primary TKA procedures comparing AIBC to non-AIBC treatment. The other two studies dealt with revision TKA procedures that compared such groups. From these papers, 4092 TKA procedures were found. 3903 of these were primary TKAs, while 189 were revision TKAs. Of the 3903 primary TKAs, 1979 of these used some form of AIBC while 1924 were part of a non-AIBC control group. Of the 189 revision TKAs, 96 of these used some form of AIBC while 93 were part of a non-AIBC control group. Average follow-up times of 47.2 mo and 62.5 mo were found in primary and revision groups respectively. A two-tailed Fisher’s exact test was done to check if infection rates differed significantly between the groups. In the primary TKA group, a statistically significant difference between AIBC and non-AIBC groups was not found (AIBC infection rate = 23/1979, non-AIBC infection rate = 35/1924, P = 0.1132). In the revision TKA group, a statistically significant difference between the groups was found (AIBC infection rate = 0/96, non-AIBC infection rate = 7/93, P = 0.0062). No statistically significant differences existed in Knee Society Scores, Hospital for Special Surgery Scores, or Loosening Rates.

CONCLUSION

AIBC did not have a significant effect on primary TKA infection rates. AIBC did have a significant effect on revision TKA infection rates.

Results of a Modular Revision System in Total Knee Arthroplasty

BACKGROUND

Revision total knee arthroplasty (TKA) poses unique challenges compared with primary TKA such as bone loss, deformity, and ligament instability. Modular component options allow flexibility to deal with these complexities. The purpose of this study was to evaluate midterm outcomes for revision TKA using a modular revision knee system with complete interchangeability and multiple options for augmentation, offset, constraint, and stem extensions.

METHODS

A query of our practice registry revealed 257 consented patients (274 knees and 278 TKA) with minimum 2-year follow-up who underwent aseptic revision TKA with a modular system (Vanguard Super Stabilized Knee; Zimmer Biomet, Warsaw, IN) between 2005 and 2013. Four patients were rerevised to a second Vanguard Super Stabilized Knee within the study period. Mean age was 68 years, and mean number of previous surgeries was 2 (1-14).

RESULTS

At mean follow-up of 6.0 years (range, 2-11 years), there have been 25 aseptic revisions involving one or more components (9.0%): 15 aseptic loosening with concomitant instability in 2, 8 others with instability, 1 with hypersensitivity, and 1 revised elsewhere for unknown cause. Ten knees were revised for infection. Range of motion improved from 100° preoperatively to 105° most recently. Knee Society clinical scores improved from 45 to 79, and function scores from 46 to 56. Radiographic evaluation revealed satisfactory position, fixation, and alignment in 97% and abnormal findings in 7 knees: 4 limited to the patella, 1 tibial radiolucency, 1 femoral and tibial radiolucency, and 1 tibial subsidence.

CONCLUSION

The results of this modular TKA revision system at 6 years mean follow-up are promising for use in complex scenarios, with a low frequency of aseptic rerevision, good knee stability, and substantial improvements in range of motion and clinical and functional outcomes.

Arthroplasty registries around the world: valuable sources of hip implant revision risk data

PURPOSE OF REVIEW

National and regional arthroplasty registries have proliferated since the Swedish Knee Arthroplasty Register was started in 1975. Registry reports typically present implant-specific estimates of revision risk and patient- and technique-related factors that can inform clinical decision-making about implants and techniques. However, annual registry reports are long and it is difficult for clinicians to extract comparable revision risk data. Since implants may appear in multiple registry reports, it is even more difficult to gather relevant data for clinical decision-making about implant selection. The purpose of this paper is to briefly describe arthroplasty registry concepts, international registries around the world, US registries, and provide a parsimonious summary of total hip arthroplasty (THA) implant revision risk reports across registries.

RECENT FINDINGS

Revision risk data for conventional stem/cup combinations reported by the Australian, R.I.P.O. (Italian), Finnish, and Danish registries are summarized here. These registries were selected because they presented 10-year data on revision risk by stem/cup combination. Four tables of revision risk are presented based on fixation: cemented, uncemented, hybrid, and reverse hybrid. Review of these tables show there is wide variation in revision risk across conventional THA implants. It also demonstrates that some cemented implants have better 10-year risk than the best uncemented implants. Many arthroplasty registries prepare annual reports that include revision risk data for implants and they are posted on the registry websites. Arthroplasty surgeons should stay current with these registry reports on implant performance and potential outliers and keep them in mind when making implant decisions.