Long-Term Implant Survivorship and Modes of Failure in Simultaneous Concurrent Bilateral Total Knee Arthroplasty

Similar QALY gain in primary and revision knee arthroplasty: A cost analysis and Markov model

PURPOSE

The aim of this study is to investigate the cost-effectiveness of revision total knee arthroplasty compared to primary total knee arthroplasty in terms of cost-per-quality-adjusted life year (QALY).

METHODS

Data were retrieved for all primary and revision total knee replacement (TKA) procedures performed at a tertiary Swiss hospital between 2006 and 2019. A Markov model was created to evaluate revision risk and we calculated lifetime QALY gain and lifetime procedure costs through individual EuroQol 5 dimension (EQ-5D) scores, hospital costs, national life expectancy tables and standard discounting processes. Cost-per-QALY gain was calculated for primary and revision procedures.

RESULTS

EQ-5D data were available for 1343 primary and 103 revision procedures. Significant QALY gains were seen following surgery in all cases. Similar, but significantly more QALYs were gained following primary TKA (PTKA) (5.67 ± 3.98) than following revision TKA (RTKA) (4.67 ± 4.20). Cost-per-QALY was €4686 for PTKA and €10,364 for RTKA. The highest average cost-per-QALY was seen in two-stage RTKA (€12,292), followed by one-stage RTKA (€8982).

CONCLUSION

RTKA results in a similar QALY gain as PTKA. The costs of achieving health gain are two to three times higher in RTKA, but both procedures are highly cost-effective.

LEVEL OF EVIDENCE

Economic level II.

Twenty-year survivorship cohort study of total knee arthroplasty in Asian patient using a single posterior-stabilized implant performed by a single surgeon

INTRODUCTION

As life expectancy has improved, the potential number of revision candidates is also expected to increase among patients who have undergone a total knee arthroplasty (TKA). The longevity of modern posterior stabilized knee prostheses after 20 years of use has not been well documented, especially in Asian populations that require a deeper flexion range due to a floor-based lifestyle.

HYPOTHESIS

Firstly, the implant longevity regarding mechanical failures such as aseptic loosening and polyethylene (PE) wear would vary over a longer follow-up depending on the age groups; and secondly there would be unique risk factors for revision surgery in an Asian TKA cohort.

MATERIAL AND METHODS

We conducted this age-stratified survival analysis in a consecutive series of 368 NexGen Legacy Posterior Stabilized (LPS) TKAs performed by a single surgeon. These cases were divided into four age groups (< 60 years, early 60s, late 60s, and ≥ 70 years). The implant longevity against aseptic mechanical failures was calculated using the Kaplan-Meier method. The revision surgery risk was evaluated using postoperative factors including a deep flexion capability (> 135̊), and postoperative mechanical alignments.

RESULTS

Overall survivorship was significantly lower in the youngest groups than other groups (Log-rank test, p=0.001). The cumulative 20-year implant longevity was more than 95% in the two oldest groups, but less than 60% in the youngest group. It was notable that the post-TKA implant longevity was not apparent up to 10 years between the age groups (p=0.073∼0.458). Aseptic loosening was observed with an earlier onset (3.1 to 18.9 years) trend than PE wear (9.8∼17.9 years), with most cases arising in the youngest groups. Flexion limitation and varus alignment were significant risks to aseptic loosening and PE wear (Cox proportional hazard regression: p=0.001 and 0.045, respectively).

DISCUSSION

A younger age (< 60 years), inability of postoperative deep flexion, and varus alignment were significant risk factors for aseptic loosening and PE wear after modern PS design in this Asian cohort. The difference in postoperative longevity affected by these factors was not obvious during the first 10 years but emerged over a second decade.

LEVEL OF PROOF

III; retrospective cohort study.

A case series of total knee arthroplasty with a non-constrained implant in 2nd and 3rd degree valgus deformity in knee osteoarthritis and medial collateral ligament insufficiency

INTRODUCTION

Osteoarthritis is one of the leading causes of disability and the most common degenerative disease of the knee that causes enormous pain. As many as 10-15 % of patients requiring total knee arthroplasty (TKA) present with valgus knee deformity. When fully constrained TKA is not possible, the surgeon must use a different method to achieve a good result.

CASE DESCRIPTION

A 56-year-old female with 3rd degree (48-degree) and a 62-year-old male with 2nd degree valgus knee (13-degree) with painful osteoarthritis were examined. Both have valgus thrust gait and medial collateral ligament (MCL) laxity and underwent TKA using non-constrained implants. During surgical exposure, MCL insufficiency was found in both patients, and MCL augmentation was performed. Post-operative assessment and 4-month follow-up were done through clinical and radiological parameters using the knee scoring system.

DISCUSSION

A good outcome could still be achieved with a primary TKA implant in severe and moderate valgus knees with MCL insufficiency using MCL augmentation. The primary TKA implant proved to improve clinical and radiological parameters after 4 months of follow-up. Clinically, both patients no longer felt pain in their knees and were able to walk with better stability. Radiologically, there was a much-reduced valgus degree. The results were the first case went from 48-degree to 2-degree and the second case went from 13-degree to 6-degree.

CONCLUSION

Knee osteoarthritis with valgus deformity and MCL insufficiency present surgical challenges during TKA. It is still possible to use in severe or moderate valgus with MCL insufficiency, which was proven by satisfactory clinical and radiological findings. Although a non-constrained option is not ideal, it is still the first choice in certain cases.

Perioperative Complications in Patients over 70 Years of Age following Simultaneous Bilateral Total Knee Arthroplasty

Single-stage bilateral total knee arthroplasty (ssBTKA) can be used for patients presenting with bilateral arthritis and may result in fewer systemic and wound complications compared with two, independent procedures. However, the safety of ssBTKA in the elderly remains controversial. Therefore, the purpose of this study was to compare early complications and transfusion rates following ssBTKA in patients ≤ 70 years old or > 70 years old. This retrospective chart review of 313 consecutive patients undergoing ssBTKA included 174 patients ≤ 70 years old and 139 patients > 70 years old. Perioperative variables and postoperative complications were compared with univariate analyses between age groups. Multivariate analyses were performed to determine risk factors for developing perioperative complications and transfusions. Compared with patients ≤ 70, patients > 70 had significantly lower body mass index (p < 0.001) and were more commonly female (p = 0.024). Although wound (p > 0.12) and systemic complications (p > 0.54) were similar, 23% of patients > 70 required transfusion compared with only 8% of patients ≤ 70 (p < 0.001). Patients with preoperative anemia (p < 0.001), age > 70 (p = 0.002), or diabetes mellitus (p = 0.007) were at 5.7, 3.3, and 2.9 times greater risk for requiring a transfusion, respectively. Patients > 70 undergoing ssBTKA have a similar complication profile to patients ≤ 70 years old, suggesting age should not be an absolute exclusion criterion for ssBTKA. However, the risk of transfusion was significantly higher in those > 70, despite lower tourniquet times. Treatment of preoperative anemia may decrease the risk of transfusion and could provide adequate safety for patients > 70 to undergo ssBTKA by an experienced surgeon.

[Knee flexion after hospitalisation is no predictor for functional outcome one year after total knee arthroplasty]

OBJECTIVE

In total knee arthroplasty (TKA), range of motion has become established as an important factor. The criterion of quality is set to flexion of 90° after hospitalisation. Currently, it is supposed to be a predictor for 1‑year postoperative outcome. However, as this correlation has not been proven, this clinical trial was performed.

METHODS

A total of 182 TKA recipients were analysed retrospectively. Outcomes were assessed before surgery, after hospitalization, 6 weeks and 1 year post surgery. They included knee range of motion (ROM) to answer the main hypothesis, but also KSS, SF-36, WOMAC, EQ-5D and VAS to evaluate knee function and quality of life. The patients were divided into two groups differing in achieving 90° flexion after hospitalisation and compared 6 weeks and 1 year after surgery.

RESULTS

Knee flexion differed significantly between groups from 91 to 70° in the group without the aim of 90° flexion after hospitalisation (E) (p < 0.001). After 6 weeks, flexion was improved to 112° ± 13° (E > 90°) vs. 106° ± 14° (E < 90°; p = 0.001). One year post surgery, knee flexion averaged 122° ± 10° (E > 90°) vs. 120° ± 10° (E < 90°) with no difference between the groups (p = 0.57) and no significant difference in all other scores concerning knee function and quality of life.

CONCLUSION

Flexion of 90° after hospitalisation is not adequate to predict medium-term outcomes after TKA. There is no advantage or disadvantage regarding whether the aim of 90° flexion is achieved.

Decreased Implant Survival is Associated With Younger Patients Undergoing Total Knee Arthroplasty

Background: Younger patients are undergoing total knee arthroplasty (TKA) at increasing rates and may face multiple revisions during their lifetimes due to mechanical complications or infections. Questions/Purposes: We sought to compare the early complication rates and revision-free implant-survival rates across age groups of patients undergoing TKA, with particular focus on implant survival in younger patients. Methods: We conducted a retrospective analysis of data taken from a national insurance database on patients who underwent primary TKA from 2007 to 2015. Kaplan-Meier curve survival analysis and log rank test were performed to evaluate revision rates in 7 age groups (younger than 40, 40-49, 50-59, 60-69, 70-79, 80-89, and 90 or more years of age). Complication rates were compared to rates in the age 60 to 79 years age groups using multiple logistic regression, controlling for baseline demographics and comorbidities. Results: There were 114,698 patients included in the analysis. Patients in the younger than 40 years, 40 to 49 years, and 50 to 59 years age groups had increased rates of early mechanical complications; 90-day readmission rates were significantly higher in those age groups as well. Revision-free implant survival at 5 years was significantly worse in patients younger than 60 years of age, particularly those less than 40 years, who had a 77% revision-free implant-survival rate at 5 years. Conclusions: Younger patients had a higher risk of early revision after TKA, as well as an increased rate of mechanical complications and readmissions at 90 days. These outcomes suggest more study is needed to better understand these discrepancies and to better guide preoperative counseling for young patients considering TKA.

Sensor-guided gap balance versus manual gap balance in primary total knee arthroplasty: a meta-analysis

Background

Despite Vast improvements in technology and surgical technique in total knee arthroplasty (TKA), approximately 15–25% TKAs, have suboptimal subjective clinical outcomes. Our study sought to evaluate if sensor-guided balancing improves postoperative clinical outcomes compared to a conventional gap balancing technique.

Methods

We searched Web of Science, Embase, PubMed, Cochrane Controlled Trials Register, Cochrane Library, Highwire, CBM, CNKI, VIP, and Wanfang database in March 2022 to identify studies involving sensor-guided balancing versus conventional gap balancing technique in TKA. Finally, we identified 2147 knees assessed in nine studies.

Results

Compared with manual gap balancing, Sensor-guided gap balancing resulted in less rate of Manipulation under anesthesia (MUA) (P = 0.02), however more rate of intraoperative additional procedures (P = 0.0003). There were no significant differences in terms of KSS (P = 0.21), KSS Function score (P = 0.36), OKS (P = 0.61), KOOS (P = 0.78), operative time (P = 0.17), Mechanical axis (P = 0.69) and rate of reoperation between two groups.

Conclusion

Compared with conventional manual gap balancing techniques, sensors have more balancing procedures being performed. However, it did result in a reduction in the rate of MUA. More extensive, high-quality RCTs are required to verify our findings further.

Short Interval Staged Bilateral Total Knee Arthroplasty: Safety Compared to Simultaneous and Later Staged Bilateral Total Knee Arthroplasty

BACKGROUND

Simultaneous bilateral total knee arthroplasty (sim-BTKA) is reported to be safe in a select group of patients. Patients with symptomatic bilateral knee arthritis who are not candidates for sim-BTKA require staged surgery (stag-BTKA). This study aimed to compare the safety and complications associated with sim-BTKA with stag-BTKA performed at 2 time intervals.

METHODS

This retrospective study of prospectively collected data includes bilateral TKA cases performed between 2001 and 2019. A cohort of sim-BTKA (n = 2728) was compared to a cohort of stag-BTKA (n = 1658). The staged group was subdivided according to the interval between surgeries: ≤90 days (early) and ≥91 days (later). Multivariate logistic regression analyses were used to adjust for confounding variables.

RESULTS

In-hospital complication rates were lower in both arms of the stag-BTKA groups vs the sim-BTKA. The sim-BTKA group had higher odds ratio of anemia, electrolyte disturbances, pulmonary embolism, and respiratory, urinary, gastrointestinal, and neurological complications. Lower rates of all-cause revision were found in stag-BTKA vs sim-BTKA groups. There was a trend toward revision due to deep infection when increasing the interim before the second stag-BTKA procedure. No differences in complication rates after the second surgery were detected between the early and later stag-BTKA.

CONCLUSION

This study demonstrates that sim-BTKA is associated with more complications and revisions when compared to stag-BTKA. Performing the second-stage TKA at 90 days or less after the first TKA is not associated with increased risk of complications. Performing sim-BTKA, simply for convenience, is not warranted and should be reserved for a select group of patient matching specific criteria.

Wear Assessment of Tibial Inserts Made of Highly Cross-Linked Polyethylene Supplemented with Dodecyl Gallate in the Total Knee Arthroplasty

Background: the wear of tibial insert is still one of primary factors leading to failure of total knee arthroplasty (TKA). Dodecyl gallate (DG) has shown improvements in the oxidation stability of highly cross-linked polyethylene (HXLPE). This study aimed to assess the application of HXLPE supplemented with DG (HXLPE-DG) on the tibial insert in TKA concerning the wear resistance and the potential impact on implant fixation; Methods: tibial inserts made of HXLPE-DG were subjected to a 3 million loading-cycle wear test following ISO 14243-1:2009. The loss of mass and wear rate of the tibial inserts were calculated. The quantity, size,- and shape of wear particles were recorded; Results: the test specimens lost an average mass of 16.00 mg ± 0.94 mg, and were on an average wear rate of 3.92 mg/million cycles ± 0.19 mg/million cycles. The content of wear particles in the calf serum medium was 3.94 × 10⁸ particles/mL ± 3.93 × 10⁷ particles/mL, 96.66% ± 0.77% of the particles had an equivalent circular diameter less than 0.5 μm. The aspect ratio of wear particles was 1.40 (min: 1.01; max: 6.42). Conclusions: HXLPE-DG displayed advantages over the commonly used materials for tibial inserts and presented the potential of application in TKA.

Cost of Aseptic Revision Total Knee Arthroplasty at a Tertiary Medical Center

BACKGROUND

Revision total knee arthroplasty (TKA) involves varying levels of case complexity and costs depending on the following: (1) number of components revised, (2) duration of operating room time, and (3) length of hospital stay. However, the cost associated with different types of aseptic TKA revisions, based on number and type of components revised, is not well described. We sought to determine differences in cost associated with different revision types, and to correlate this with average national hospital and surgeon reimbursement based on current Centers for Medicare and Medicaid Services data.

METHODS

This is a retrospective review of aseptic revision TKAs performed at a single tertiary referral center from 2015 to 2018. Patient demographic data, operating room time, and direct surgery and total hospital costs obtained from an internal accounting database (Enterprise Performance Systems, Inc) were collected. Patients were stratified by the components revised (polyethylene liner only, tibia only, femur only, or both femur and tibia). We hypothesized that direct surgery and total hospital costs would increase as case complexity increased from poly exchange to single-component revisions and both-component revisions.

RESULTS

In total, 106 patients were included (19 poly exchanges, 10 tibia-only revisions, 13 femur-only revisions, and 64 both-component revisions). Operating room time was significantly lower for poly exchange than all other groups (P < .001). Direct surgery and total hospital costs were significantly lower for poly exchange than all other groups (P < .001), and were significantly lower for tibia-only and femur-only revisions compared to both-component revisions (P < .001). Average national surgeon reimbursement by Medicare decreased as a percentage of direct surgery cost as case complexity increased from poly exchange to tibia-only, femur-only, and both-component revisions. Total hospital cost per average Diagnosis Related Group weight was lowest for single-component revisions and highest for both-component revision.

CONCLUSION

There are significant differences in cost associated with aseptic TKA revisions based on number and type of components revised. These differences may not be accurately reflected in reimbursement, and often represent a burden to those who treat complex revisions.