Patient satisfaction and outcome after septic versus aseptic revision total knee arthroplasty

Complications of periprosthetic fracture revision vs aseptic revision of total knee arthroplasty

Background

Periprosthetic fractures after total knee arthroplasty (TKA) are a challenging problem due to complex fracture patterns, poor bone quality, and a high-risk patient population. Treatment of both periprosthetic fractures and aseptic complications can include revision TKA. In this study, we compared systemic and orthopaedic complications following periprosthetic fracture associated revision TKA to aseptic revision TKA.

Methods

This is a retrospective cohort study using data from the years 2010-2020 from a national administrative claims database. Billing codes were used to identify revision TKAs with a diagnosis of periprosthetic fracture or aseptic complications (loosening, dislocation, arthrofibrosis, osteolysis, or prosthetic wear) within one year prior to revision. Pertinent systemic complications and rates of repeat revision TKA, periprosthetic infection, and repeat fractures were compared between the two groups.

Results

We identified 9891 periprosthetic fracture associated revision TKAs and 47,071 aseptic revision TKAs. Our study found higher rate of systemic complications including AKI, DVT, wound disruption, hematoma, and surgical site infections in periprosthetic fracture associated revision TKA compared to aseptic revision TKA. Furthermore, we found higher rates of repeat revision TKA, periprosthetic infections, and repeat periprosthetic fractures in fracture associated revision TKA group compared to aseptic revision group.

Conclusions

Our work highlights the significant short- and long-term complications associated with periprosthetic fracture associated revision TKA. Future working comparing functional outcomes and optimal surgical techniques are needed.

Clinical Outcomes and Complications of 2-Stage Septic Versus Aseptic Revision Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

Although several studies have compared the clinical outcomes of septic and aseptic revision total knee arthroplasty (TKA), their results have been controversial. Therefore, this study aimed to compare clinical outcomes and complications of septic and aseptic revision TKA through a systematic review and meta-analysis.

METHODS

The PubMed (MEDLINE) and Embase databases were searched for studies evaluating the clinical outcomes and complications of 2-stage septic revision and aseptic revision TKAs. A systematic review of clinical outcomes (Knee Society Knee and Function Scores and range of motion) and complications (reoperation, infection, and failure rates) was conducted.

RESULTS

Thirteen studies were included in the systematic review. The mean MINORS (Methodological Index for NOn-Randomized Studies) score of the included studies was 20.5 (range, 18 to 22). The meta-analysis revealed higher reoperation (risk ratio [RR], 1.98; 95% confidence interval [CI], 1.50 to 2.62; p < 0.00001), infection (RR, 4.08; 95% CI, 2.94 to 5.64; p < 0.00001), and failure rates (RR, 2.88; 95% CI, 1.38 to 6.03; p = 0.005) in septic revision TKAs than in aseptic revision TKAs. Moreover, septic revision TKAs showed lower Knee Society Knee Scores compared with aseptic TKAs (mean difference [MD], -6.86; 95% CI, -11.80 to -1.92; p = 0.006). However, the Knee Society Function Score (MD, -1.84; 95% CI, -7.84 to 3.80; p = 0.52) and range of motion (MD, -6.96°; 95% CI, -16.23° to 2.31°; p = 0.14) were not significantly different between septic and aseptic revision TKAs.

CONCLUSIONS

Despite the heterogeneity of prosthesis designs and surgical protocols used in septic and aseptic revision TKAs, the results of this systematic review suggest that 2-stage septic revision TKAs have poorer clinical outcomes and higher complication rates than aseptic revision TKAs do.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

The Fate of the Inconclusive Periprosthetic Joint Infection Workup and Reliability of Data Points

In 2018, periprosthetic joint infection (PJI) criteria were revised to include a new category labeled "inconclusive." The purpose of this study was to characterize and describe the fate of the inconclusive PJI workup and to analyze preoperative factors associated with outcomes. We reviewed all PJI workups at our institution during a 3-year period (426 patients). Patients were labeled "infected," "not infected," or "inconclusive" according to 2018 PJI preoperative criteria. In addition to standard diagnostic variables, the presence or absence of clinical elements that increase the pretest probability of infection were collected. Patients with any missing preoperative diagnostic test results and those with clinical follow-up less than 30 days were excluded. Logistic regression was used to identify the factors associated with infection. Two hundred ninety-six workups remained after exclusion criteria were applied, consisting of 66 (22.2%) with a preoperative score of 6 or greater defined as infected, 52 (17.6%) inconclusive (score 2-5), and 178 (60.1%) not infected (score 0-1). Postoperative re-scoring of the inconclusive group based on intraoperative findings as per the 2018 criteria identified 6 of 52 (11.5%) as infected, 12 (23.1%) inconclusive, and 34 (65.4%) not infected. Among those preoperatively scored as inconclusive, variables statistically correlated with the presence of infection included history of PJI, factors that increase skin barrier penetration (eg, psoriasis and venous stasis), and presence of comorbidities predisposing to infection. For patients labeled inconclusive, clinical elements of the pretest probability for infection (eg, history of prior PJI) were as reliable as any diagnostic test, including alpha-defensin, in the diagnosis of PJI. [Orthopedics. 2023;46(5):e291-e297.].

Clinical Outcomes and Infection Rates Following Revision Total Knee Arthroplasty: Aseptic Failure versus Septic Failure

Background

It is controversial whether revision total knee arthroplasty (TKA) due to septic failure shows inferior clinical outcomes compared with TKA due to aseptic failure. Moreover, few studies have compared the infection rates after revision TKA between aseptic and septic failure. We aimed to compare the clinical outcomes and infection rates after aseptic and septic revision TKA.

Methods

Between April 2006 and May 2019, 68 and 26 patients underwent revision TKA due to aseptic failure (aseptic group) and septic failure (septic group), respectively. The postoperative range of motion (ROM), Western Ontario and McMaster Universities Osteoarthritis index, Knee Society Knee Score (KSKS), Knee Society Function Score (KSFS), and infection rates were compared between the two groups.

Results

The mean follow-up durations in the aseptic and septic groups were 44.4 and 54.8 months, respectively. The septic group showed inferior postoperative ROM (124.1° and 109.4°, p = 0.004), KSKS (88.9 and 78.8, p = 0.001), and KSFS (72.8 and 59.0, p = 0.001). Three patients of aseptic group had infection. Three patients of septic group had recurred infection (same pathogen with the first infection) and 1 patient had a new infection (different pathogen). The septic group showed slightly higher but not significantly different infection rates (4.4% and 15.4%, p = 0.089).

Conclusions

Revision TKA with septic failure showed inferior postoperative clinical outcomes compared with aseptic revision surgery. A slightly higher infection rate was observed in the septic group but it was not significantly different.

Handmade articulating spacer for two-stage exchange at the knee

OBJECTIVE

Two-stage exchange with implantation of a temporary spacer is considered gold standard treatment for chronic periprosthetic joint infection of the knee. This article describes a simple and safe technique for handmade articulating spacers at the knee.

INDICATION

Chronic or relapsing periprosthetic joint infection of the knee.

RELATIVE CONTRAINDICATIONS

Known allergy against components of polymethylmethacrylate (PMMA) bone cements or admixed antibiotics. Inadequate compliance for two-stage exchange. Patient not able to undergo two-stage exchange. Bony defect situation at the tibia or femur leading to collateral ligament insufficiency. Soft tissue damage with need for plastic temporary vacuum-assisted wound closure (VAC) therapy.

SURGICAL TECHNIQUE

Removal of the prosthesis, thorough debridement of necrotic and granulation tissue, tailoring bone cement with antibiotics. Preparation of a tibial and femoral stem. Customizing the tibial and femoral articulating spacer components to bony anatomy and soft tissue tension. Confirmation of correct position by intraoperative radiography.

POSTOPERATIVE MANAGEMENT

Protection of the spacer with an external brace. Restricted weight-bearing. Passive range of motion as possible. Intravenous-followed by oral antibiotics. Reimplantation after successful treatment of infection.

Principles of mechanical and chemical debridement with implant retention

BACKGROUND

Periprosthetic joint infection (PJI) is one of the most common causes of early revision for total hip and knee arthroplasty. Mechanical and chemical debridement typically referred to as debridement, antibiotics, and implant retention (DAIR) can be a successful technique to eradicate PJI in acute postoperative or acute hematogenous infections. This review will focus specifically on the indications, techniques, and outcomes of DAIR.

DISCUSSION

The success of mechanical and chemical debridement, or a DAIR operation, is reliant on a combination of appropriate patient selection and meticulous technique. There are many technical considerations to take into consideration. One of the most important factors in the success of the DAIR procedure is the adequacy of mechanical debridement. Techniques are surgeon-specific and perhaps contribute to the large variability in the literature on the success of DAIR. Factors that have been shown to be associated with success include the exchange of modular components, performing the procedure within seven days or less of symptom onset, and possibly adjunctive rifampin or fluoroquinolone therapy, though this remains controversial. Factors that have been associated with failure include rheumatoid arthritis, age greater than 80 years, male sex, chronic renal failure, liver cirrhosis, and chronic obstructive pulmonary disease.

CONCLUSIONS

DAIR is an effective treatment option for the management of an acute postoperative or hematogenous PJI in the appropriately selected patient with well-fixed implants.

Assessment of patient satisfaction following revision total knee arthroplasty

BACKGROUND

Patient satisfaction is becoming an increasingly important measure of healthcare quality. Satisfaction following RTKA is poorly described within the literature, resulting in difficulty for clinicians to manage patient expectations and obtain informed consent.

METHODS

We investigated postoperative satisfaction of RTKA patients by a single surgeon, using a single prosthesis, at a single institution. Patient satisfaction was assessed using structured telephone assessment questionnaires and review of orthopaedic/hospital records. The effect of patient and surgical characteristics on satisfaction was assessed using correlation coefficients and binary logistic regression in SPSS.

RESULTS

Two hundred and two RTKAs were performed in 178 patients between 2004 and 2015 inclusive. One hundred and twenty-four patients (143 RTKAs) were contactable to complete satisfaction assessment. Eighty-five percent of patients were satisfied and would have the RTKA again, 8% were unsure, 7% would not. Mean reported satisfaction on a numerical scale (1-10) was 8.17 (range 1-10), with 74% of patients scoring 8 or above, and 35% of patients scoring 10. The Mahomed Satisfaction Scale outcomes demonstrated a mean score of 87.7. High positive correlation was found between assessment tools. Logistic regression analysis identified factors contributing to satisfaction included ROM, OKS, BMI, and surgical time.

CONCLUSION

This cohort demonstrated high patient satisfaction rate following RTKA, utilizing simple and reliable outcome measurement tools. We found a high positive correlation between methods of assessment, and moderate positive correlation between satisfaction and functional outcomes. These results contribute to the understanding of satisfaction in RTKA patients, which may assist in informing patients of expected post-operative outcomes.

Preliminary outcomes following revision total knee arthroplasty using a new fixed-bearing revision knee system in Asians: a mean of 3-year follow-up

PURPOSE

The purpose of this study was to investigate the early outcomes of the new semi-constrained revision total knee arthroplasty (TKA) system by performing subgroup analysis according to the revision cause.

MATERIALS AND METHODS

From August 2019 to July 2020, 83 revision TKAs using the fixed-bearing Attune® revision knee system with a minimum follow-up of 2 years were retrospectively reviewed. Clinically, the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, the Western Ontario and McMaster Universities Osteoarthritis Index, and range of motion (ROM) were evaluated. The incidence of systemic and specific postoperative complications was investigated. Each cohort was divided into septic (group A, 34 patients) and aseptic mode (group B, 41 patients), and compared to assess the outcomes.

RESULTS

The mean age at the time of revision was 73.3 years (range 59.0 to 84.0 years), and the follow-up duration was 36.1 months (range 30.0 to 40.0 months). Clinical outcomes and ROM significantly improved at last follow-up (p < 0.001). Group A showed statistically inferior clinical outcomes in the last follow-up compared to group B. Four knees (5.3%) had a postoperative femoral joint line elevation of more than 5 mm. There were no serious systemic complications. One patient underwent re-revision TKA due to recurrence of infection. No stem tip impingement or cortical erosion was observed in all patients.

CONCLUSIONS

Revision TKAs using a new semi-constrained revision system showed favorable short-term follow-up outcomes, with improvement in clinical scores and ROM. Moreover, by using stem offsets, no postoperative stem tip impingement or cortical erosion was found.

LEVEL OF EVIDENCE

Level IV, Retrospective Case Series.

Factors affecting range of motion following two-stage revision arthroplasty for chronic periprosthetic knee infection

Introduction

The purpose of this study was to evaluate factors that affect range of motion (ROM) following two-stage revision arthroplasty as a treatment for chronic periprosthetic knee infection.

Materials and methods

A total of 98 patients diagnosed with chronic periprosthetic joint infection (PJI) following primary total knee arthroplasty between January 2009 and December 2019 and then underwent two-stage revision arthroplasty were reviewed retrospectively. Multiple regression analysis was performed to evaluate the factors that affect ROM after two-stage revision arthroplasty. ROM after two-stage revision arthroplasty was used as a dependent variable, while age at the time of surgery, ROM at PJI diagnosis, ROM after the first-stage surgery, the interval between the first-stage surgery and the second-stage surgery, whether a re-operation was performed before the second-stage surgery, culture results (culture negative or culture positive), and body mass index (BMI) were used as independent variables.

Results

Multiple regression analysis (R2 = 0.843) revealed that among the independent variables, ROM (β = 0.604, P < 0.001) after the first-stage surgery, whether a re-operation was performed before the second-stage surgery (β =  − 8.847, P < 0.001), the interval between the first-stage surgery and the second-stage surgery (β = − 0.778, P = 0.003), and BMI (β =  − 0.698, P = 0.041) were associated with ROM after two-stage revision arthroplasty, the dependent variable.

Conclusions

In two-stage revision arthroplasty for chronic periprosthetic knee infection, ROM after the first-stage surgery, whether a re-operation was performed before the second-stage surgery, the interval between the first-stage surgery and the second-stage surgery, and BMI were found to be factors that were associated with ROM after two-stage revision arthroplasty.

Common Wound Irrigation Solutions Produce Different Responses in Infected vs Sterile Host Tissue: Murine Air Pouch Infection Model

Background

Despite desirable microbicidal actions of irrigation solutions in surgical site infection treatment, several studies demonstrate potential cytotoxic effects. This study investigated tissue damage caused by irrigation solutions in the presence or absence of infection.

Methods

Air pouches were created in 60 mice and evenly divided into 2 groups as infected with Staphylococcus aureus and control. Groups were then subdivided both by type of solution and by timing after irrigation. Solutions included control (0.9% saline), bacitracin (33 IU/ml), 0.2% sodium oxychlorosene, 0.05% chlorhexidine gluconate, and 0.013% benzalkonium chloride.

Results

Inflammation decreased in infected pouches compared to the sterile ones for all solutions except bacitracin on day 0 and for all on day 7. On day 0, infected pouches had increased necrosis with bacitracin (P = .006), chlorhexidine gluconate (P = .18), and benzalkonium chloride (P = .07); on day 7, there was decreased necrosis in infected pouches for all solutions (P < .05) except for sodium oxychlorosene (P = .18). Edema decreased in infected pouches on day 0 for all solutions. On day 7, infected pouches had decreased edema with 0.9% saline, bacitracin, and benzalkonium chloride (P < .05) and increased edema with chlorhexidine gluconate (P < .05) and sodium oxychlorosene (P = .069). Bacitracin allowed for more bacteria growth than sodium oxychlorosene (P = .024), chlorhexidine gluconate (P = .025), and benzalkonium chloride (P = .025).

Conclusions

The presence of bacteria led to less immediate tissue inflammation and edema, while tissue necrosis varied over time. The current study may guide surgeons on which solution to use and whether to irrigate a possibly sterile wound or joint.

Are Static Spacers Superior to Articulated Spacers in the Staged Treatment of Infected Primary Knee Arthroplasty? A Systematic Review and Meta-Analysis

In the treatment of knee periprosthetic joint infection with a two-stage protocol, static spacers allow for the local delivery of high doses of antibiotics and help to preserve soft tissue tension. Articulated spacers were introduced to better preserve flexion after the reimplantation. The aim of this systematic review is to provide a comprehensive data collection of the results of these different spacers. An in-depth search on the main clinical databases was performed concerning the studies reporting data on the topic. A total of 87 studies and 4250 spacers were included. No significant differences were found both in pooling data analysis and meta-analysis of comparative studies about infection recurrences, complications, and clinical scores. Mean active knee flexion at last follow-up after total knee reimplantation was found to be significantly higher using articulated spacers (91.6° ± 7° for static spacers vs. 100.3° ± 9.9° for articulated spacers; p < 0.001). Meta-analysis also recognized this strong significant difference (p < 0.001). This review has confirmed that articulated spacers do not appear to be inferior to static spacers regarding all clinical outcomes, while they are superior in terms of active flexion. However, the low quality of the studies and the risk for selection bias with complex patients preferentially treated with static spacers need to be accounted for.

Similar outcomes to primary total knee arthroplasty achievable for aseptic revision using the same primary posterior-stabilised prosthesis at a mean follow-up of 49 months

PURPOSE

The aim of the study was to compare clinical and radiological outcomes between primary and aseptic revision TKAs using the same posterior-stabilised (PS) prosthesis. The authors hypothesised similar outcomes between both groups for selected patients.

METHODS

This retrospective, case-control study assessed 36 patients who underwent aseptic revision TKA compared to a match group of 72 primary TKA. Both groups had the same PS design implant (ANATOMIC®, Amplitude, Valence, France). The International Knee Society (IKS) score, radiological outcomes (postoperative alignment, patellar tilt and radiolucent lines), re-intervention and revision rate were compared between the two groups with a minimum follow-up of 3 years.

RESULTS

The final study cohort included 29 patients and 63 patients respectively in the revision and primary group, with a mean follow-up of 49.1 months (range 36.1-69). Postoperatively, there was no significant difference in IKS scores between the two groups [169.8 for the revision group and 179.6 for the primary group (p = 0.09)]. No statistical difference was observed for post-operative satisfaction 86.2% versus 92.1% (p = 0.46). Between the two groups, there was no difference in mean radiological assessment, including radiolucent lines (p = 0.7). There was no significant difference for overall implant survivorship 96.5% versus 100% (p = 0.13) at 36 months.

CONCLUSION

Similar clinical, radiological and survivorship outcomes were found between rTKA and primary TKA groups using the same PS level of constraint in patients undergoing revision surgery for aseptic indications at 3-year follow-up. Use of PS implants in rTKA for the correct indication suggests this to be a safe approach at least in the medium term.

LEVEL OF EVIDENCE

IV, retrospective case-control study.

Use of antibiotic-cement coated locking plates in the setting of periprosthetic infection and infected nonunion

INTRODUCTION

In the setting of periprosthetic total hip and knee arthroplasty (THA/TKA) infection, plating of the femur may be necessary for fracture fixation, prophylactic fixation of the femur, poor bone quality, or infected femoral shaft nonunion. The purpose of this study was to investigate infection control rates and fracture healing in patients receiving antibiotic cement coated plates in the setting of infected nonunion and periprosthetic infections.

METHODS

We retrospectively reviewed a series of ten patients who had an antibiotic coated plate placed in the setting of periprosthetic infection or infected nonunion with a minimum follow-up of six months. 80 g of Simplex bone cement (Stryker, Mahwah, NJ) were mixed with 4 g of powdered vancomycin and 4.8 g of powdered tobramycin and applied to a dynamic compression plate with locking screw guides in every hole. The antibiotic loaded cement was allowed to harden before implantation. Outcome measures were designed to assess for fracture healing defined as three out of four cortices united on radiographs along with bearing full weight without pain and evidence of infection control defined as normalized erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in the absence of antibiotic treatment with no clinical signs of infection.

RESULTS

Ten patients were treated with an antibiotic cement coated plate in the settings of infectious nonunion and periprosthetic infection and followed for an average of three years (mean 21.4 months, seven months to 61 months). Eight patients (80%) went on to successful control of infection after initial procedure. Two patients developed chronic drainage and had a second antibiotic spacer with antibiotic cement coated plate placed before the infection was controlled. All patients obtained successful control of infection at latest follow-up showing no clinical signs of infection, normalized laboratory markers, and negative culture results. There were no reported mechanical failures of the implant, fractures of the femur, or soft tissue complications.

CONCLUSION

An antibiotic cement coated plating technique is a viable option for periprosthetic THA and TKA infections requiring plating of the femur or in patients with an infected nonunion.

Risk of Instability After Revision Total Knee Arthroplasty for Periprosthetic Joint Infection

Periprosthetic joint infection (PJI) remains a major source of morbidity after total knee arthroplasty (TKA). The risk of recurrent infection has been more extensively studied than the risk of mechanical failure. We sought to define the incidence of instability after revision TKA for PJI and to compare this incidence with that for revision TKA for instability. We retrospectively reviewed patients treated by 4 arthroplasty surgeons at 1 institution. The primary outcome was a new diagnosis of clinical instability after index revision. We analyzed potential risk factors that may contribute to postoperative instability after PJI, including demographic characteristics, implant alignment, number of previous procedures, level of constraint during index revision, and type of spacer used. Patients were matched 1:1 with patients undergoing revision TKA for instability. Continuous variables were compared with Student's t test for normally distributed variables and Mann-Whitney U test for non-normal variables. Categorical variables were compared with Fisher's exact test. Thirty-seven patients who underwent revision TKA for PJI were identified. Twelve (32.4%) had clinical instability after revision, compared with only 3 (8.1%) in the matched cohort (P=.019). Use of a revision, midlevel constraint device in the PJI cohort did not correlate with a lower risk of instability (P=.445). A greater number of previous surgical procedures increased the likelihood of instability (P=.041). Revision TKA for PJI is associated with a high risk of subsequent instability. Midlevel constrained implants may not be sufficient to prevent instability. A focus on soft tissue tension and a lower threshold for increasing constraint may be prudent in this cohort. [Orthopedics. 2022;45(3):145-150.].

Clinical Outcomes Following Revision Total Knee Arthroplasty: Minimum 2-Year Follow-up

Backgroud

The longer-term outcomes of revision total knee arthroplasty are not well described in the current literature. Managing patient expectations of revision total knee arthroplasty can be challenging for orthopedic surgeons due to a paucity of data to guide decision-making. We present outcomes of revision total knee arthroplasty performed by a single surgeon over a 12-year period from 2004 through 2015.

Methods

A retrospective review of hospital and private medical records demonstrated 202 revision total knee arthroplasties performed by the senior author in 178 patients from 2004 through 2015. Of these, 153 patients were available for assessment. Patients were contacted and invited to participate in a structured telephone interview to assess Oxford Knee Score (OKS) and patient satisfaction. All patients received the PFC (Depuy) prosthesis at a single institution and were followed up for minimum 2 years postoperatively at the time of review. Retrospective chart review was used to obtain other data for analysis including patient demographics, preoperative and postoperative range of motion (ROM), and intraoperative details.

Results

This cohort demonstrated a 93.5% survival rate and an 85% satisfaction rate at a mean of 6.5 years postoperatively. Mean ROM improved from 100° (range, 5°–145°) to 112° (range, 35°–135°) (p < 0.001). The mean OKS was 39.25 (range, 14–48). The factors associated with improved postoperative outcomes included male gender, fewer previous revision total knee arthroplasty procedures, increased preoperative ROM, and receiving a less constrained implant.

Conclusions

This study provides a comprehensive description of outcomes following revision total knee arthroplasty in a large patient cohort with a long follow-up. Although revision total knee arthroplasty is a challenging and complex aspect of arthroplasty surgery, high patient satisfaction and good functional outcomes can be achieved for the majority of patients.

MAKO CT-based robotic arm-assisted system is a reliable procedure for total knee arthroplasty: a systematic review

PURPOSE

The aim of this study was to investigate the clinical and radiological results of the MAKO CT-based robotic-assisted system for total knee arthroplasty (TKA).

METHODS

A PRISMA systematic review was conducted using four databases (MEDLINE, EMBASE, Pubmed, GOOGLE SCHOLAR) to identify all clinical and radiological studies reporting information regarding the use and results of the CT-based robotic-assisted system to perform TKA between 2016 and 2020. The main investigated outcome criteria were postoperative pain, analgesia requirements, clinical scores, knee range of motion, implant positioning and the revision rate. The ROBINS-I tool (Risk Of Bias In Non-randomized Studies of Interventions) was used to evaluate the quality of included studies and the risk of bias.

RESULTS

A total of 36 studies were identified, of which 26 met inclusion criteria. Of these 26 studies, 14 were comparative. The follow-up varied from 30 days to 17 months. This CT-based, saw cutting Robotic TKA is associated with a significantly lower postoperative pain score (2.6 versus 4.5) and with significantly reduced time to hospital discharge (77 h versus 105), compared with conventional TKA. The two comparative studies assessing functional outcomes at 1 year reported significantly better functional scores with CT-based robotic TKA compared with conventional TKA (WOMAC score: 6 ± 6 versus 9 ± 8 (p < 0.05); KSS function score: 80 versus 73 (p = 0.005)). Only three comparative studies assessed implant positioning, and these reported better implant positioning with CT-based robotic-assisted TKA.

CONCLUSION

The CT-based robotic-assisted system for TKA reduced postoperative pain and improved implant positioning with equal or slightly superior improvement of the functional outcomes at one year, compared to conventional TKA.

LEVEL OF EVIDENCE

Systematic review level IV.

Cost-effectiveness of Single vs Double Debridement and Implant Retention for Acute Periprosthetic Joint Infections in Total Knee Arthroplasty: A Markov Model

Background

Periprosthetic joint infection (PJI) is a common cause of revision total knee surgery. Although debridement and implant retention (DAIR) has lower success rates in the chronic setting, it is an accepted treatment of acute PJI, whether postoperatively or with late hematogenous seeding. There are two broad DAIR strategies: single debridement and planned double debridement. The purpose of this study is to evaluate the cost-effectiveness of single vs double DAIR for acute PJI in total knee arthroplasty.

Methods

A decision tree using single or double DAIR as the treatment strategy for acute PJI was constructed. Quality-adjusted life years and costs associated with the two treatment arms were calculated. Treatment success rates, failure rates, and mortality rates were derived from the literature. Medical costs were derived from both the literature and Medicare data. A cost-effectiveness plane was constructed from multiple Monte Carlo trials. A sensitivity analysis identified parameters most influencing the optimal strategy decision.

Results

Double DAIR was the optimal treatment strategy both in terms of the health utility state (82% of trials) and medical cost (97% of trials). Strategy tables demonstrated that as long as the success rate of double debridement is 10% or greater than the success rate of a single debridement, the two-stage protocol is cost-effective.

Conclusions

A double DAIR protocol is more cost-effective than single DAIR from a societal perspective.

Poor outcomes of revision total knee arthroplasty in patients with septic loosening compared to patients with aseptic loosening

Background

The purpose of this study was to compare the functional outcomes, activity levels, mortalities, implant survival rates, and complications in revision total knee arthroplasty (TKA) of patients with septic loosening with those in patients with aseptic loosening over a minimum 10-year follow-up period.

Methods

A cohort of 78 patients (36 septic loosening and 42 aseptic loosening) was selected between January 2008 and December 2009. The functional outcomes, activity levels, mortalities, implant survival rates, and complications of revision TKA in patients with septic and aseptic loosening were compared.

Results

The mean Knee Society knee scores in the septic and aseptic groups improved from 36.7 and 37.4 preoperatively to 65.3 and 76.8 points at the final follow-up, respectively (p < 0.05). Outdoor ambulatory patients at the final follow-up included 20 of 29 (69.0%) patients in the septic group and 35 of 39 (89.7%) patients in the aseptic group (p < 0.05). The cumulative mortality rates in the septic and aseptic groups were 19.4% (7/36) and 7.1% (3/42) (p = 0.102) at final follow-up, respectively. Kaplan–Meier survivorship analysis with re-revision of either component as an endpoint in the septic and aseptic groups estimated 86.5% and 95.5% chance of survival for 10 years, respectively.

Conclusions

Revision TKA in patients with septic loosening had worse functional outcomes and higher mortality over a minimum 10-year follow-up period compared with that in patients with aseptic loosening.

Level of evidence

IV.

Optimal designs and surgical technique for hip and knee joint replacement: The best is yet to come!

Over the last three decades, there have been significant advancements in knee and hip replacement technology. The implants and the surgical technology we now have to aid in their implantation are advancing and improving functional outcomes and survivorship. Despite these advancements, there are still issues with patient satisfaction, functional limitations, and early revisions due to instability and aseptic loosening. This article reviews the state of current technology in hip and knee replacement implant design and surgical technique, and reviews some of the current implant designs and surgical technologies that may be able to solve some of the most common issues in the knee and hip replacement surgery.

Infection and periprosthetic fracture are the leading causes of failure after aseptic revision total knee arthroplasty

AIM

The purpose of this study was to clarify the medium to long term survival of aseptic revision total knee arthroplasty (RTKAs) and identify the common modes of failure following RTKAs.

MATERIALS AND METHODS

A multi-center, retrospective study included all aseptic RTKAs performed at three tertiary referral hospitals between 2003 and 2016. Patients were excluded if the revision was for prosthetic joint infection (PJI) or they had previously undergone revision surgery. Minor revisions not involving the tibial or femoral components were also excluded. Demographics, surgical data and post-operative outcomes were recorded and analyzed. Survival analysis was performed and the reasons for revision failure identified.

RESULTS

Of 235 aseptic RTKAs identified, 14.8% underwent re-revision at mean follow-up of 8.3 years. Survivorship of RTKA was 93% at 2 years and 83% at 8 years. Average age at revision was 72.9 years (range 53-91.5). The most common reasons for failure following RTKA were periprosthetic joint infection (PJI) (40%), periprosthetic fracture (25.7%) and aseptic loosening (14.3%). Of those whose RTKA failed, the average survival was 3.33 years (8 days-11.4 years). No demographic or surgical factors were found to influence RTKA survival on univariate or multivariate analysis.

CONCLUSION

PJI and periprosthetic fracture are the leading causes of re-revision surgery following aseptic revision TKA. Efforts to improve outcomes of aseptic revision TKA should focus on these areas, particularly prevention of PJI.

Küntscher nails with static cement spacer: A simple technique in periprosthetic knee infections with massive bone loss and instability

BACKGROUND

Two-stage revision for periprosthetic knee infection is challenging in cases of massive bone loss and instability. The present study aims to describe our experience with an alternative technique of reinforced cement spacer, usually necessary in these situations, focusing on its advantages and clinical results.

METHODS

We retrospectively identified all patients who underwent a two-stage revision for periprosthetic knee infection using two intramedullary Küntscher nails as reinforcement from January 2010 to September 2018. From each medical record, we extracted the type of explanted prosthesis, isolated micro-organism, number of cement spacers before index procedure (and related episodes of spacer dislocation) and final treatment.

RESULTS

Twelve patients were identified, mean age of 64.0 years (range 39-85). In four of them, the reinforced spacer was used twice for persistent infection, with a total of 16 procedures performed and no cases of dislocation. Ten patients were finally treated with reimplantation or arthrodesis with intramedullary nails, whereas an above-knee amputation was necessary for two patients. Infection was eradicated in 10 patients out of 12 (83%) at a mean follow up of 34.3 months (range 10-62).

CONCLUSIONS

This technique is an effective alternative to traditional spacers in cases of massive bone loss, producing a mechanically stable joint and preserving adequate tissue tensions. The construct is technically easy to perform and, not less importantly, to remove during stage 2. Further studies, with larger groups, are necessary to determine its validity.

Results at 10-24 years after single-stage revision arthroplasty of infected total hip arthroplasty in patients under 45 years of age

INTRODUCTION

The management of periprosthetic joint infection (PJI) of the hip is a challenging procedure. One-stage exchange is carried out in specialist centres with comparable infection free survival rates. However, there is a paucity of long-term results of this approach in young patients.

METHODS

All patients undergoing one-stage exchange due to PJI with a known causative organism ⩽45 years of age with a minimum of 10-year follow-up (mean 15 years; range 10-24 years) were enrolled in this retrospective study. Patients older than 45 years of age or patients with a two-stage procedure were excluded from the study. The primary outcome measure was failure rate with special focus on reinfection at latest follow-up. Failure was defined as revision surgery for infection. Furthermore, functional outcome using the Harris Hip Score was determined initially and at latest follow-up. 26 patients fulfilled the inclusion criteria and were available for final follow-up.

RESULTS

The study cohort consists of 16 male and 10 female patients with a mean age of 36.8 years (range 20-45 years) and a mean BMI of 29.8 kg/m2 (range 20.7-40.6 kg/m2). Prior to the single-stage procedure, the patients underwent an average of 3.1 previous surgical interventions (range 1-9). The mean hospital stay after septic revision was 19.7 days (11-33 days). Most infections were caused by Staphylococcus epidermidis (n = 8, 30.8%), followed by Staph. aureus (n = 7, 26.9%) and Propionibacterium acnes (n = 6, 23.1%). At latest follow-up, the overall survival rate was 76.9 %, while infection control could be achieved in 96.2%. At final examination, the mean Harris Hip Score improved from 46.2 to 78.9 (range 18.0-99; SD, 22.6).

CONCLUSIONS

Single-stage revision surgery for the management of PJI in patients ⩽45 years is a successful treatment option with high infection control, even after long-term follow-up.

The use of cement in revision total knee arthroplasty

Despite the availability of modern implants and techniques, Revision Total Knee Arthroplasty (R-TKA) still poses a challenge to surgeons, particularly the management of bone loss/defects and the secure fixation of implants. Polymethylmethacrylate (PMMA) bone cement plays an important role for fixation as fully uncemented fixation in RTKA is rarely used. Cement can be employed as part of a full cementing construct or as a hybrid construct. While in fully cemented implants, the diaphyseal stem as well as any couplers or connectors in the metaphysis are cemented, in hybrid cementing, only the component parts at the joint surface and metaphysis are cemented, while the diaphyseal stem is fixed in a press-fit manner. In this article the literature on the in vitro as well on the in vivo results of both fixation options is reviewed. Although the fixation mechanism of both constructs are different, radiographic and clinical survivorship appear similar for both techniques. Although there appears to be a trend towards a hybrid fixation method, the choice of which technique to employ in revision total knee arthroplasty will depend on the surgeons' familiarity with each technique as well as the factors peculiar to each patients anatomy.

Do Prosthetic Joint Infections Worsen the Functional Ambulatory Outcome of Patients with Joint Replacements? A Retrospective Matched Cohort Study

OBJECTIVES

To assess the effect on the functional ambulatory outcome of postoperative joint infection (PJI) cured at the first treatment attempt versus not developing PJI in patients with hip and knee prostheses.

METHODS

In a single-hospital retrospectively matched cohort study, each patient with PJI between 2007 and 2016 was matched on age, sex, type of prosthesis and year of implantation with two other patients with uninfected arthroplasties. The definition of a PJI cure included infection eradication, no further surgical procedures, no PJI-related mortality and no suppressive antibiotics. Functional ambulatory status evaluated one year after the last surgery was classified into four simple categories: able to walk without assistance, able to walk with one crutch, able to walk with two crutches, and unable to walk. Patients with total hip arthroplasties (THA), total knee arthroplasties (TKA) and partial hip arthroplasty (PHA) were analysed separately.

RESULTS

A total of 109 PJI patients (38 TKA, 41 THA, 30 PHA) and 218 non-PJI patients were included. In a model adjusted for clinically relevant variables, PJI was associated with a higher risk of needing an assistive device for ambulation (vs. walking without aid) among THA (adjusted odds ratio (OR) 3.10, 95% confidence interval (95% CI) 1.26-7.57; p = 0.014) and TKA patients (OR 5.40, 95% CI 2.12-13.67; p < 0.001), and with requiring two crutches to walk or being unable to walk (vs. walking unaided or with one crutch) among PHA patients (OR 3.05, 95% CI 1.01-9.20; p = 0.047).

CONCLUSIONS

Ambulatory outcome in patients with hip and knee prostheses with postoperative PJI is worse than in patients who do not have PJI.

Patient-reported Outcome Measures of Revision Total Hip Arthroplasty for Prosthetic Joint Infection is not Inferior to Aseptic Revision Total Hip Arthroplasty

Introduction:

This study aims to investigate whether patients undergoing two-stage revision total hip arthroplasty (THA) for prosthetic joint infection (PJI) and one-stage revision THA for aseptic reasons have similar clinical outcomes and patient satisfaction during their post-operative follow-up. We hypothesise that the two-stage revision THA for PJI is associated with poorer outcomes as compared to aseptic revision THA.

Materials and Methods:

We reviewed prospectively collected data in our tertiary hospital arthroplasty registry and identified patients who underwent revision THA between 2001 and 2014, with a minimum of two years follow-up. The study group (two-stage revision THA for PJI) consists of 23 patients and the control group (one-stage revision THA for aseptic reasons) consists of 231 patients. Patient demographics, Western Ontario and McMaster Universities Arthritis Index (WOMAC), Oxford Hip Score (OHS), Short Form-36 (SF-36) scores and patient reported satisfaction were evaluated. Student’s t-test was used to compare continuous variables between the two groups. Statistical significance was defined as p <0.05.

Results:

The pre-operative demographics and clinical scores were relatively similar between the two groups of patients. At two years, patients who underwent revision THA for PJI reported a better WOMAC Pain Score and OHS as compared to aseptic revision THA. A similar proportion of patients were satisfied with their results of surgery in both groups (p=0.093).

Conclusions:

Although patients who underwent revision THA for PJI had poorer pre-operative functional scores (WOMAC function and SF-36 PF), at two years follow-up, these two groups of patients have comparable post-operative outcomes. Interestingly, patients who had revision THA for PJI reported a better clinical outcome in terms of OHS and WOMAC Pain score as compared to the aseptic group. We conclude that the revision THA for PJI is not inferior to aseptic revision THA in terms of patient satisfaction and clinical outcomes.

Polyethylene-Based Knee Spacer for Infection Control: Design Concept and Pre-Clinical In Vitro Validations

Antibiotic-loaded polymethyl methacrylate (PMMA) has been widely applied in the treatment of knee periprosthetic joint infections. However, problems with antibiotic-loaded PMMA-based spacers, such as structural fracture and implant dislocation, remain unresolved. A novel polyethylene-based spacer, designed with an ultra-congruent articulating surface and multiple fenestrations, was introduced in the current study. Validation tests for biomechanical safety, wear performance, and efficacy of antibiotic cement were reported. During cycle fatigue testing, no tibial spacer failures were observed, and less wear debris generation was reported compared to commercial PMMA-based spacers. The volumetric wear of the novel spacer was within the safety threshold for osteolysis-free volumetric wear. An effective infection control was demonstrated despite the application of lesser antibiotic cement in the 30-day antibiotic elution test. The tube dilution test confirmed adequate inhibitory capabilities against pathogens with the loaded antibiotic option utilized in the current study. The novel polyethylene-based knee spacer may offer sufficient biomechanical safety and serve as an adequate carrier of antibiotic-loaded cement for infection control. Further clinical trials shall be conducted for more comprehensive validation of the novel spacer for practical application.

Robotic-assisted total knee arthroplasty is comparable to conventional total knee arthroplasty: a meta-analysis and systematic review

BACKGROUND

Total knee arthroplasty (TKA) is a successful procedure in managing end-stage arthritis when non-operative treatments fail. New technologies such as robotic TKA (rTKA) have been developed to improve the accuracy of prosthesis implantation. While short-term cohort studies on rTKA have shown excellent results, the evidence comparing between rTKA and conventional TKA (cTKA) is not yet well established. This meta-analysis aims to compare the efficacy and safety of rTKA versus cTKA in terms of clinical outcomes, radiographic results, complications, peri-operative parameters and costs.

METHODS

A multi-database search was performed according to PRISMA guidelines. Data from studies comparing between rTKA and cTKA were extracted and analyzed.

RESULTS

Eighteen studies were included in this review, consisting of 2234 rTKA and 4300 cTKA. Robotic TKA led to a more precise prosthesis implantation with significantly fewer outliers in the mechanical axis (p < 0.001), femoral coronal (p = 0.002) and tibial sagittal (p = 0.01) alignments. Only the Hospital for Special Surgery (HSS) (p < 0.001) score at final follow-up was significantly better in rTKA than cTKA. rTKA also had a lower mean blood loss (p < 0.001) despite a longer mean operation time (p = 0.006). There were no statistically significant difference in terms of other clinical outcome measures, range of motion and complications.

CONCLUSION

Both rTKA and cTKA are reliable and safe to perform. However, rTKA is capable of achieving superior alignment in several axes, lower mean blood loss and this may lead to marginally better clinical outcomes than cTKA.

EVIDENCE LEVEL

Level II, Meta-analysis of non-homogeneous studies.

Satisfaction Rates Are Low following Revision Total Knee Arthroplasty in Asians Despite Improvements in Patient-Reported Outcome Measures

With the aging population in Asia and increase in total knee arthroplasty (TKA) utilization rates, the number of patients requiring revision TKA (rTKA) are expected to increase as well. The purpose of this study was to evaluate outcomes and satisfaction rates following rTKA in an Asian population that has unique cultural demands. Registry data of patients who underwent rTKA from 2006 to 2010 and had completed 5 years of follow-up were analyzed. Flexion range, Oxford Knee score (OKS), Knee Society score (KSS), the Short-Form 36 (SF-36), and satisfaction rates were assessed for improvement from preoperative values, as well as by the minimum clinically important difference (MCID) criterion. rTKA was performed in 163 patients. There were significant improvements seen at 2 years postoperatively and these were sustained up to 5 years. The minimal clinically important difference (MCID) criterion for KSS, OKS, and SF-36 physical component score (PCS) was met at 2 and 5 years postoperatively. The overall complication rate was 3.7% at a mean follow-up of 8.4 years. A total of 121 patients (74.2%) were satisfied at 5 years postoperatively. Within our cohort, rTKA results in significantly improved patient-reported outcome measures with a low complication rate of 3.7% at a minimum of 5-year follow-up. Despite these encouraging results, satisfaction rates remain low.

Modified hybrid cementing technique reduces stem tip pain and improves patient's satisfaction after revision total knee arthroplasty

Background

There have been no studies comparing patient-reported outcome measures including end-of-stem tip pain and patient satisfaction based on the use of cementing techniques in revision total knee arthroplasty (TKA). The purpose of this study was to compare end-of-stem tip pain and PROMs with hybrid and modified hybrid cementing techniques in revision TKAs.

Method

Sixty-two cases of revision TKA performed by a single surgeon were divided into two groups based on the cementing technique with a minimum follow-up of 2 years. Two types of cementing technique for femoral and tibial stems were used as follows: (1) a hybrid cementing technique (33 cases), in which cement was applied immediately distal to the modular junction of the stem and the component while the distal stem was press-fitted into the diaphysis without using cement; and (2) a modified hybrid cementing technique (29 cases), in which cement was applied to the tip of femoral and tibial stems. The thigh and shin were assessed for the end-of-stem tip pain. Patient satisfaction was evaluated based on the satisfaction items of New Knee Society Score.

Results

Modified hybrid cementing significantly lowered the percentage of patients manifesting shin pain (3.4% vs. 24.2%, p = 0.029). Patients treated with the modified hybrid cementing technique showed a higher satisfaction rate (p = 0.003). Multivariate logistic regression analysis showed an increase in the odds of satisfaction 32.686-fold (p = 0.004) in patients without pain at the end-of-stem tip in the shin and 9.261-fold (p = 0.027) in patients treated with the modified hybrid cementing technique.

Conclusion

The modified hybrid cementing technique for fixation of long-stem in revision TKAs reduced the end-of-stem tip pain in the shin, leading to significantly higher satisfaction compared with the hybrid cementing technique after revision TKA.

Level of evidence

Level III

New materials for hip and knee joint replacement: What's hip and what's in kneed?

Over the last three decades there have been significant advancements in the knee and hip replacement technology that has been driven by an issue in the past concerning adverse local tissue reactions, aseptic and septic loosening. The implants and the materials we utilize have improved over the last two decades and in knee and hip replacement there has been a decrease in the failures attributed to wear and osteolysis. Despite these advancements there are still issues with patient satisfaction and early revisions due to septic and aseptic loosening in knee replacement patients. This article reviews the state of current implant material technology in hip and knee replacement surgery, discusses some of the unmet needs we have in biomaterials, and reviews some of the current biomaterials and technology that may be able to solve the most common issues in the knee and hip replacement surgery.

Is a full component revision necessary for isolated tibial loosening?

Aims

Aseptic 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.

Methods

Patients 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.

Results

The 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.

Conclusion

Isolated 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.

2020 Mark Coventry Award: Microorganism-directed oral antibiotics reduce the rate of failure due to further infection after two-stage revision hip or knee arthroplasty for chronic infection: a multicentre randomized controlled trial at a minimum of two years

Aims

The aim of this study was to determine if a three-month course of microorganism-directed oral antibiotics reduces the rate of failure due to further infection following two-stage revision for chronic prosthetic joint infection (PJI) of the hip and knee.

Methods

A total of 185 patients undergoing a two-stage revision in seven different centres were prospectively enrolled. Of these patients, 93 were randomized to receive microorganism-directed oral antibiotics for three months following reimplantation; 88 were randomized to receive no antibiotics, and four were withdrawn before randomization. Of the 181 randomized patients, 28 were lost to follow-up, six died before two years follow-up, and five with culture negative infections were excluded. The remaining 142 patients were followed for a mean of 3.3 years (2.0 to 7.6) with failure due to a further infection as the primary endpoint. Patients who were treated with antibiotics were also assessed for their adherence to the medication regime and for side effects to antibiotics.

Results

Nine of 72 patients (12.5%) who received antibiotics failed due to further infection compared with 20 of 70 patients (28.6%) who did not receive antibiotics (p = 0.012). Five patients (6.9%) in the treatment group experienced adverse effects related to the administered antibiotics severe enough to warrant discontinuation.

Conclusion

This multicentre randomized controlled trial showed that a three-month course of microorganism-directed, oral antibiotics significantly reduced the rate of failure due to further infection following a two-stage revision of total hip or knee arthroplasty for chronic PJI. Cite this article: Bone Joint J 2020;102-B(6 Supple A):3–9.

Functional recovery after two-stage short-interval revision of chronic periprosthetic knee joint infection

PURPOSE

The objective of this study was the functional recovery analysis of patients treated in two-staged short-interval procedure due to knee periprosthetic joint infection (PJI).

MATERIALS AND METHODS

In the period from January 2015 to December 2018, a two-stage short-interval revision TKA was performed in 35 patients with PJI. Synovial fluid analysis, tissue samples and sonication method were used to diagnose PJI. Active range of motion (AROM) and Hospital for Special Surgery (HSS) score were analysed.

RESULTS

Functional recovery analysis demonstrated higher AROM and HSS score after the revision TKA. Median pre-operative active flexion motion was 80° with full active extension, and median post-operative active flexion was 105° with full active extension. Median HSS score pre-operatively was 22 and post-operatively was 48. Isolated bacteria in both tissue and sonication fluid were S. epidermidis (27%) and other coagulase-negative staphylococci (25%), followed by S. aureus (10%).

CONCLUSION

Two-stage short-interval procedure of chronic knee PJI significantly improved functional status of patients in a short period of time. Thirty three out of 35 patients returned to their everyday activities. Adequate surgical technique and implant selection can lead to satisfactory functional outcome.

Gender and Preoperative Function Predict Physical Activity Levels After Revision Total Knee Arthroplasty

BACKGROUND

The incidence of revision total knee arthroplasty (TKA) is projected to increase 6-fold worldwide by 2030. As the number of younger, physically active revision TKA patients increases in future, understanding factors influencing postoperative function will be increasingly important to help counsel patients. The primary aim of this study was to examine factors influencing return to physical activity following revision TKA.

METHODS

Patients who had undergone tibiofemoral revision between 2003 and 2013 at a single UK teaching hospital were retrospectively identified from a prospectively collected arthroplasty database. Preoperative activity level (University of California, Los Angeles [UCLA] score), patient demographics, indication, implant used, and Oxford Knee Scores (OKSs) were recorded in the database. At a mean follow-up of 3.9 years (standard deviation, 2.2), UCLA score, OKS, EuroQol-5 Dimension Score (EQ-5D), satisfaction, complications, and WORQ scores (Work, Osteoarthritis and Joint-Replacement Questionnaire) were sampled via postal questionnaire. Patient experience of complications and related surgery was also identified from healthcare records. Univariate and multivariate analyses were performed.

RESULTS

Responses were received from 112 revision TKAs (112 patients; mean age, 71 years). Mean UCLA activity scores improved from preoperative levels (P < .001): activity levels improved in 47% of patients with 58% engaging in moderate or more intensive activities (UCLA score ≥5). Postoperative activity level was independently predicted by male gender (P = .042) and preoperative UCLA score (P < .001). Increasing social deprivation was associated with inferior UCLA (P = .005), EQ-5D (P < .005), and OKS (P = .006) scores. Indication, implant type, and patient body mass index did not affect functional outcome or satisfaction (P > .05). Patients <65 years old were more likely to be dissatisfied (P = .009), and patients aged ≤55 years were more likely to report difficulties with WORQ criteria (P < .05).

CONCLUSION

Although 90% of patients maintain activity levels following revision TKA, less than half increase levels and this is predicted by male sex and pre-revision activity level.

Clinical and radiographic outcomes of a hybrid fixation revision total knee arthroplasty system at short to mid-term follow-up

BACKGROUND

Despite the extensive study of primary arthroplasty, revision surgery is rarely discussed due to the reduced frequency and variability between patients. A new revision knee system was introduced to build off the geometry of a successful knee replacement system. This study seeks to assess the survival, clinical outcomes and radiographic assessment of this revision system at the early to mid-term.

METHODS

A consecutive cohort of 234 rTKAs was identified from an institutional database. Survival analysis was assessed for aseptic loosening and any-cause failure. Patient outcome measures were the Oxford Knee Score (OKS) and patient reported satisfaction. Radiographs were assessed in accordance with the Knee Society radiographic scoring system. Mechanical alignment was assessed on three-foot standing radiographs.

RESULTS

Aseptic survivorship at one year, two years, and five years was 100%, 100%, and 99.1%, respectively. Any-cause survival at one, two, and five years was 99.6%, 98.7%, and 92.3%, respectively. OKS improved from pre-op (average 18.8) to one year (average 31.7), two years (average 30.7), and mid-term (average 30.6) follow-up (p < 0.001 for all). At all intervals, patient satisfaction exceeded 70%. One component (0.4%) failed radiographically and was later revised. Neutral mechanical alignment was achieved in 83% of cases. In the remaining cases, alignment was in varus (10%) or valgus (seven percent). No consistent relationship between radiographs or mechanical alignment and clinical outcomes was noted.

CONCLUSION

The survivorship, clinical, and radiographic outcomes of the single rTKA system studied are equivalent or superior to other hybrid fixation rTKA systems reviewed in the literature at similar follow-up intervals.

Is there a difference in joint line restoration in revision Total knee arthroplasty according to prosthesis type?

Background

The aim of this study is (1) to compare joint line (JL) restoration and clinical outcomes in revision TKA based on the contemporary prosthesis type and (2) to determine the restoration of posterior condylar offset (PCO) according to the use of a femoral offset stem.

Methods

Sixty knees that underwent revision TKA from April 2003 to December 2013 with a minimum of 1 year follow up were included. These were further subdivided into three groups according to prosthesis type: group I (2 mm offset), group II (4.5 mm offset), group III (2, 4, and 6 mm offset). The JL position change was defined as a change in the adductor tubercle distance, preoperatively versus postoperatively. We also collected the change of PCO in distal femur and clinical outcomes including range of motion (ROM) and knee scores at the preoperative and last follow-up periods.

Results

The JL elevation for group III was significantly lower than that of the other groups. Usage of the tibial and femoral offset stem in group III was more frequent than in the other groups. PCO in revision TKA with a femoral offset stem was significantly greater than in those with a femoral straight stem. The JL position in revision TKA with a femoral offset stem was less elevated than in those with a femoral straight stem.

Conclusions

More recent developed revision prosthesis with various sizes option of offset stem may be effective in restoring the native joint line as using the femoral offset stem more convenience in revision TKAs.

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.

A dedicated anticoagulation clinic does not improve postoperative management of warfarin after total joint arthroplasty

Background

Periprosthetic joint infections (PJIs) are devastating complications. Excessive anticoagulation with warfarin is an independent risk factor for PJIs. The use of a dedicated anticoagulation clinic to improve warfarin management has not been proven.

Methods

Between 2006 and 2014, we identified 92 patients who were placed on postoperative warfarin, and later developed PJI. These patients were compared to 313 patients who underwent total joint arthroplasty placed on warfarin without developing PJI. Patients were included if they had no history of a venous thromboembolic event, were warfarin naive, and enrolled in the anticoagulation clinic. A univariate analysis compared independent variables, and statistical analysis was performed using Student's t-test and Pearson chi-square test for continuous and categorical variables.

Results

Thirty-six PJI patients and 297 control patients met the inclusion criteria. The venous thromboembolism rate was 2.1%. At discharge, 82% of all patients were subtherapeutic. Patients were within their target international normalized ratio (INR) range 26.7% of the time. The mean INR in the initial postoperative period for the PJI group was 1.46 and 1.29 in the control group (P < .001). In the acute postoperative period, 13.3% of the knee PJI group were therapeutic or supratherapeutic compared with 3.5% in the knee control group (P = .002).

Conclusions

Despite utilization of a dedicated anticoagulation clinic, patients were only within their target INR range 27% of the time. Total knee arthroplasty patients who developed a PJI were more likely to be therapeutic or supratherapeutic in the initial postoperative period. Consequently, the risks associated with warfarin as a venous thromboembolism prophylaxis may outweigh the potential benefits.

Periprosthetic Joint Infection Does Not Preclude Good Outcomes after a Revision Total Knee Arthroplasty: A 7-Year Follow-Up Study of 144 Retrospective Cases

Background and Purpose

Debate exists on whether septic revision total knee arthroplasty (TKA) results in inferior clinical outcomes, and limited information is available regarding the factors associated with such outcomes. This study aimed to (1) compare clinical outcomes and characteristics of aseptic versus septic revision TKA and (2) identify the risk factors associated with inferior clinical outcomes.

Methods

We retrospectively reviewed 144 revision TKAs (90 aseptic and 54 septic revisions) that were followed for a minimum of 3 years (mean = 7 years). Clinical outcome data, namely, Knee Society knee and function scores and the Hospital for Special Surgery knee score, were collected. We reviewed 13 pre- and intraoperative variables.

Results

Postoperative clinical outcomes were inferior in septic revision surgeries (p<0.05). In regression analyses, however, septic revision was not an independent risk factor for poor clinical outcomes. The independent risk factors for poor outcome were identified where Anderson Orthopedic Research Institute grade 3 femoral and tibial bone defects, more than three surgeries, and treatment for persistent infection were associated with inferior clinical outcomes (all p<0.05). Standard two-stage septic revision without grade 3 bone defects or additional surgeries showed comparable outcomes to aseptic revision.

Interpretation

Clinical outcomes of septic revision were inferior to those of aseptic revision. However, poor outcomes were mainly associated with large bone defects and an increased number of surgeries. The outcomes of aseptic and septic revision surgery were similar when patients with larger bone defects and more than three surgeries were excluded.

Diagnosis of Prosthetic Joint Infection: Cultures, Biomarker and Criteria

Prosthetic joint infections (PJIs) are devastating complications after joint arthroplasty that continue to pose a diagnostic challenge. Currently, a single, stand-alone test with the adequate accuracy and reliability for diagnosis of PJI is not available; therefore, physicians who care for patients with PJI must rely on a combination of diagnostic tests for the diagnosis of PJI. This article reviews conventional laboratory test modalities, diagnostic accuracy and limitations of current tests, and novel emerging tests for the diagnosis of PJI.

Are the Outcomes of Revision Knee Arthroplasty for Flexion Instability the Same as for Other Major Failure Mechanisms?

BACKGROUND

Aseptic loosening, infection, and flexion instability have emerged as the leading etiologies for revision after total knee arthroplasty (TKA). Although studies have reported improved outcomes after revision TKA, the relative functional and clinical outcomes of patients revised for flexion instability and other failure etiologies have not been extensively reported. The aim of the study was to compare the functional and patient-reported outcomes of revision TKA for the common failure etiologies.

METHODS

We retrospectively reviewed records of 228 consecutive cases of revision TKA from 2008 to 2014. Revisions performed for aseptic loosening (n = 53), septic revisions (n = 48), and isolated flexion instability (n = 45) with a minimum of 18 months follow-up were included for analysis. Revision for all other etiologies (n = 82) were excluded. The Modified Knee Society Score (KSS), KSS Function, and Western Ontario and McMaster Universities Osteoarthritis Index were recorded for all cases. A 7-point Likert scale was used to record patient's perception of outcomes after revision surgery and analyzed based on etiology.

RESULTS

Although all groups showed improvement in outcome after revision TKA, the changes in Modified KSS and KSS-Function varied according to the etiology of failure of the primary procedure with the smallest improvement being reported by the flexion instability group.

CONCLUSION

Patients undergoing revision for isolated flexion instability have less improvement in functional outcome as compared with other etiologies. We hypothesize this is due to a higher baseline preoperative knee function in the flexion instability group.

A regional registry study of 216 patients investigating if patient satisfaction after total knee arthroplasty changes over a time period of five to 20years

AIMS

To determine the temporal changes in patient dissatisfaction following primary knee arthroplasty surgery (TKA).

PATIENTS AND METHODS

Three hundred and ninety patients that had previously indicated they were either dissatisfied or unsure with their TKA at one-year post-surgery in our region were mailed a simple questionnaire in addition to the Oxford Knee Score and EQ-5D.

RESULTS

A 55% response rate was achieved. The mean follow-up time period was 9.1years. Of the 120 patients who were initially dissatisfied, 46.7% remained so. Of the 96 patients who were initially unsure, 20.8% remained so, 21.9% and 57.3% became dissatisfied and satisfied, respectively. The primary reason for continued dissatisfaction was persistent pain. Of the 19.4% of patients who had revision surgery, 47.6% remained dissatisfied. 54.2% of patients stated that they would be happy to have a primary TKA again and 55.6% indicated that they would recommend one to a friend. Patients who had concurrent hip pain were six times more likely to remain unsure or dissatisfied over time (OR 6.7, p-value 0.0000). Patients who had back pain or contralateral knee pain were two or three times as likely to remain unsure or dissatisfied.

CONCLUSION

In time half of the patients who stated that they were not satisfied with their arthroplasty, at one year, go on to be satisfied with their knee.

Primary hip and knee arthroplasty in a temporary operating theatre is associated with a significant increase in deep periprosthetic infection

Aims

Infection following total hip or knee arthroplasty is a serious complication. We noted an increase in post-operative infection in cases carried out in temporary operating theatres. We therefore compared those cases performed in standard and temporary operating theatres and examined the deep periprosthetic infection rates.

Patients and methods

A total of 1223 primary hip and knee arthroplasties were performed between August 2012 and June 2013. A total of 539 (44%) were performed in temporary theatres. The two groups were matched for age, gender, body mass index and American Society of Anesthesiologists grade.

Results

The deep infection rate for standard operating theatres was 0 of 684 (0%); for temporary theatres it was eight of 539 (1.5%) (p = 0.001).

Conclusion

Use of a temporary operating theatre for primary hip and knee arthroplasty was associated with an unacceptable increase in deep infection. We do not advocate the use of these theatres for primary joint arthroplasty. Cite this article: Bone Joint J 2017;99-B:917–20.

Causes and Clinical Outcomes of Revision Total Knee Arthroplasty

Purpose

The purpose of this study was to evaluate causes and clinical outcomes of revision total knee arthroplasty (TKA) with a minimum 2-year follow-up.

Materials and Methods

We performed a retrospective review on the records of 225 revision TKAs performed from 2003 to 2012 at a single institution. Finally, 206 cases were conducted. To evaluate clinical outcomes, we checked the range of motion (ROM), Knee Society (KS) score, Hospital for Special Surgery (HSS) score, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score preoperatively, 6 months postoperatively and yearly thereafter and complications after revision TKA.

Results

The causes of revision TKA were septic complications in 120 and aseptic complications in 86. The main aseptic complication was periprosthetic fracture in 36, followed by 25 loosening, 13 polyethylene wear and 9 instability. At the final follow-up, patients showed improvements in ROM and KS, HSS and WOMAC scores. Of the total, 7 patients underwent re-revision due to reinfection in 6 and periprosthetic fracture in 1.

Conclusions

Due to development of implants and surgical techniques, mechanical complications such as aseptic loosening and instability that need a revision decreased whereas septic complications relatively increased. Therefore, we should be cautious for the occurrence of infection. Overall, revision TKA provided clinical improvement in knee function and patient satisfaction.

Contemporary failure aetiologies of the primary, posterior-stabilised total knee arthroplasty

Aims

The number of revision total knee arthroplasties (TKA) that are performed is expected to increase. However, previous reports of the causes of failure after TKA are limited in that they report the causes at specific institutions, which are often dependent on referral patterns. Our aim was to report the most common indications for re-operations and revisions in a large series of posterior-stabilised TKAs undertaken at a single institution, excluding referrals from elsewhere, which may bias the causes of failure.

Patients and Methods

A total of 5098 TKAs which were undertaken between 2000 and 2012 were included in the study. Re-operations, revisions with modular component exchange, and revisions with non-modular component replacement or removal were identified from the medical records. The mean follow-up was five years (two to 12).

Results

The Kaplan-Meier ten-year survival without a re-operation, modular component revision and non-modular component revision was 95.7%, 99.3% and 95.3%, respectively. The most common indications for a re-operation were: post-operative stiffness (58%), delayed wound healing (21%), and patellar clunk (11%). The indications for isolated modular component revision were acute periprosthetic joint infection (PJI) (64%) and instability (36%). The most common indications for non-modular component revision were chronic PJI (52%), aseptic loosening (17%), periprosthetic fracture (10%), and instability (10%).

Conclusion

Post-operative stiffness remains the most common indication for re-operation after TKA. Infection is the most common indication for modular and non-modular component revision. Aseptic loosening was not an uncommon cause of failure, however, it was much less common than in national registry and non-registry data. Focusing on posterior-stabilised TKAs initially performed at our institution allowed for an accurate assessment of the causes of failure in a contemporary specialty practice. Cite this article: Bone Joint J 2017;99-B:647–52.

A UK national survey of care pathways and support offered to patients receiving revision surgery for prosthetic joint infection in the highest volume NHS orthopaedic centres

Background

Deep prosthetic joint infection (PJI) is a devastating complication of joint replacement surgery. It is difficult to treat, and patients often require multiple major revision surgeries to eradicate the infection. Treatment can have negative and long‐term impact on patients' quality of life. Understanding current service provision provides valuable information needed to design and evaluate support interventions for patients.

Aim

This survey aimed to identify usual care pathways and support in UK National Health Service (NHS) orthopaedic centres for patients receiving revision surgery for PJI after hip or knee replacement.

Methods

The 20 highest volume NHS orthopaedic centres treating prosthetic joint infection after hip or knee replacement were approached. Consultant orthopaedic surgeons specializing in treating PJI were invited to participate in a telephone or email survey about usual care provision and support for PJI.

Findings

Sixteen centres completed the survey. Findings showed a high degree of variation nationally in follow‐up time‐points after revision surgery. Multidisciplinary approaches to care focused more on clinical care and physical rehabilitation than social and psychological care. Patient management and referral to support services also varied and barriers to referrals included lack of availability or access to services, lack of knowledge of services, shortage of staff, and complexities of referring outside of the hospital catchment area.

Conclusions

Our findings suggest that future development of interventions should focus on more inclusive and patient‐centred multidisciplinary approaches to care. Such interventions could more completely address psychological and social as well as physical aspects of patients' recovery.