Short-to-Midterm Outcomes of Revision Total Knee Arthroplasty Patients With a Total Stabilizer Knee System

Effect of Knee Valgus Deformity on Symptomatic Venous Thromboembolism and Prosthesis Revision Risk after Total Knee Arthroplasty: A Multicenter Retrospective Study

OBJECTIVE

Symptomatic venous thromboembolism (VTE) and prosthesis failure are the most serious complications after total knee arthroplasty (TKA). However, whether knee valgus deformity aggravates these complications has not been fully clarified. To study the difference between perioperative symptomatic VTE and prosthesis revision rate in patients with valgus knee osteoarthritis by comparing with patients undergoing TKA for varus deformity and analyze the reasons for revision. At the same time, the distribution and radiographic features of lower extremity deep venous thrombosis were recorded.

METHODS

The data of patients who underwent TKA in two tertiary hospitals from January 2016 to December 2020 were retrospectively reviewed, and a total of 8917 patients were included. According to preoperative manifestations of knee malformations, all patients were divided into two groups: valgus group (n = 412) and varus group (n = 8505). Main indicators included the incidence of symptomatic VTE and prosthesis revision. Secondary outcomes included general information on operative time, Kellgren and Lawrence score, total hospital stay, and total costs. The patient data of the two groups were analyzed by Pearson chi-square test, Student t test, or Mann-Whitney U test. The revision was evaluated using Kaplan-Meier survival analysis.

RESULTS

The proportion of valgus knees in TKA patients was 4.62% (412/8917). The incidence of VTE was 6.23‰ (53/8505) and 16.99‰ (7/412) in the varus and valgus groups, and the results were statistically different (p = 0.009). There was no significant difference in echogenicity, number of occluded vessels, and thrombus length between the valgus group (p = 0.102; p = 0.645; p = 0.684). Patients with valgus deformity had 12.14‰ (5/412) prosthesis revision, the incidence of varus deformity was 4.82‰ (41/8505), and the revision risk of valgus group was 2.5 times higher than varus group, and the results were statistically different (p = 0.043). The operation time and hospital stay in the valgus group were longer than those in the varus group, and the results were statistically different (p = 0.018; p < 0.001).

CONCLUSIONS

Valgus deformity increases risk of symptomatic VTE and prosthesis revision after TKA. These results have guiding significance for the prevention of complications after TKA in patients with valgus deformity.

Condylar constrained and rotating hinged implants in revision knee arthroplasty show similar survivorship and clinical outcome: a systematic review and meta-analysis

PURPOSE

In revision total knee arthroplasty (TKA) ligament instability and bone defects might require more constraint implants such as a condylar constrained knee (CCK) or rotating hinged knee (RHK). When both implants are suitable, the choice remains controversial. The purpose of this systematic review and meta-analysis was to compare the survivorship and clinical outcome between CCK and RHK in revision TKA.

METHODS

Systematic literature research was performed. Studies analysing the clinical outcome and/or survivorship of CCK and/or RHK in revision TKA were included. Clinical outcomes included the Knee Society Score, both clinical (KSCS) and functional (KSFS), range of motion (ROM) and reoperations. Survival was defined as the time free from removal or revision of the femoral and/or tibial component.

RESULTS

A total of 40 articles analysing 4.555 knees were included. Survival did not differ between RHK and CCK implants (p = 0.6058), with, respectively, 91.6% and 89.8% survival after 5 years. Postoperative KSCS and KSFS were, respectively, 79.2 (SD 10.7) and 61.1 (SD 21.8) for the CCK group. Similar scores were noted for the RHK group with a KSCS of 80.2 (SD 14.1) and KSFS of 58.5 (SD 17.3). Postoperative ROM was similar for CCK (105.3°, SD 17.1°) and RHK patients (104.1°, SD 16.9°).

CONCLUSION

This meta-analysis revealed that both survivorship and clinical outcome are similar for CCK and RHK patients for whom both designs are technically suitable and indicated.

LEVEL OF EVIDENCE

IV.

Extended Oral Antibiotic Prophylaxis After Aseptic Revision TKA: Does It Decrease Infection Risk?

BACKGROUND

Extended oral antibiotic prophylaxis (EOA) has been shown to potentially reduce infection rates after high-risk primary total knee arthroplasties (TKAs) and reimplantations. However, data is limited regarding EOA after aseptic revision TKAs. This study evaluated the impact of EOA on infection-related outcomes after aseptic revision TKAs.

METHODS

904 aseptic revision TKAs from 2014-2019 were retrospectively identified. Patients who received EOA >24 hours perioperatively (n = 267) were compared to those who did not (n = 637) using an inverse probability of treatment weighting model. Mean age was 66 years, mean BMI was 33 kg/m², and 54% were female. Outcomes included cumulative probabilities of any infection, periprosthetic joint infection (PJI), superficial infection, and re-revision or reoperation for infection.

RESULTS

The cumulative probability of any infection after aseptic revision TKA was 1.9% at 90 days, 3.5% at 1 year, and 8.1% at 5 years. Patients without EOA had a higher risk of any infection at 90 days (HR = 7.1; P = .01), but not other time points. The cumulative probability of PJI after aseptic revision TKA was 0.8% at 90 days, 2.3% at 1 year, and 6.5% at 5 years. Patients without EOA did not have an increased risk of PJI. There were no differences in re-revision or reoperation for infection at any time point between groups.

CONCLUSION

Extended oral antibiotics after aseptic revision TKA were associated with a 7-fold decreased risk of any infection at 90 days. The results suggest a potential role for EOA after aseptic revision TKA and warrant additional prospective studies.

LEVEL OF EVIDENCE

Level III.

Revision Total Knee Arthroplasty With the Use of Restricted Kinematic Alignment Protocol: Surgical Technique and Initial Results

Purpose: Kinematic alignment (KA) for primary total knee arthroplasty (TKA) has been shown to provide equivalent or better results to mechanical alignment (MA). The use of KA in revision TKA to restore the individual knee anatomy, kinematics, and soft-tissue balance, has not been documented yet. The purpose of this study is to describe the technique for performing TKA revision using the restricted KA (rKA) protocol and to report (1) rerevision rate and adverse events, (2) patient-reported outcome measures (PROMs), and (3) radiological signs of implant dysfunction related to this technique.

Methods: The rKA protocol was used in 43 selected TKA revisions cases suitable for the technique. Adverse events, reoperation, revision, and their causes were recorded. In addition, PROMs assessed by WOMAC score and radiographic evaluation to identify signs of implant dysfunction were documented at last follow-up.

Results: After a mean follow-up of 4.0 years (0.9–7.7, ±2), only one rerevision (2.3%) was required for persisting instability (polyethylene liner exchange from posterior stabilized to a semi-constrained). Short-cemented stems were used for both the femur and tibia in 28 (65%) cases, for the femur alone in 13 (30%) cases, and no stems in two cases. In 31 (72%) cases, a standard posterior stabilized tibial insert was used, while 12 (28%) cases required a semi-constrained insert. The mean WOMAC score was 34.4 (0–80, ±21.7). Mean postoperative arithmetic hip-knee-ankle angle (HKA) was 0.8° varus (from 5° varus to 4° valgus), mean mechanical distal femoral angle was 1.7° valgus (from 2° varus to 5° valgus), and mean mechanical tibia proximal angle was 2.2° varus (from 5° varus to 1° valgus). No radiological evidence of aseptic loosening or periprosthetic radiolucencies were identified.

Conclusion: Although current revision TKA implants are not ideal for revision TKA performed with rKA, they are an appealing alternative to MA, especially in cases of early, non-wear-related, unsuccessful MA TKAs. rKA TKA revision using short-cemented stems in conjunction with meticulous preoperative planning is safe in the mid-term.

Level of evidence: IV

Can Revision TKA Patients Achieve Similar Clinical Functional Improvement Compared to Primaries?

The etiology of failure following primary total knee arthroplasty (TKA) leading to revision surgery are multifactorial, including infection, instability, loosening, contracture, and wear. Although the majority of patients have successful outcomes following revision TKA, postoperative complications are still increased in these patients when compared to primary patients. For this reason, there has been a continued search to identify options, including prosthesis types, to potentially improve outcomes. Therefore, the purpose of this study was to determine if the clinical results achieved following revision TKA are comparatively similar to primaries using the same implant design. Specifically, we compared (1) Knee Society Functional and Range-of-Motion Knee Scores and (2) component survivorship. This was a retrospective analysis of 100 patients undergoing revision TKA due to an aseptic etiology, who were matched to a cohort of 100 patients who underwent primaries with the same prosthesis. There were no differences in the groups with respect to age at surgery, sex, and body mass index. The mean follow-up was 57 months in the revision group (range 24-105 months) and 67 months in the primary TKA group (range 55-123 months). American Knee Society Scores (KSS) and range of motion measurements recorded preoperatively and at the most recent postoperative visit were compared between both cohorts in order to compare postoperative outcomes. A p value of 0.05 was used for significance. The average improvement between the pre- and postoperative KSS function scores in both groups was similar, with both cohorts demonstrating a 28-point improvement. At 2-year follow-up, all-cause survivorship of the aseptic revision surgeries was 87%. Patients undergoing revision TKA for aseptic loosening can potentially expect similar improvements in clinical function scores and survivorship compared to primary TKA when controlling for implant type.

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.

Metaphyseal Fixation Using Highly Porous Cones in Revision Total Knee Arthroplasty: Minimum Two Year Follow Up Study

BACKGROUND

Highly porous metaphyseal cones have been introduced to restore metaphyseal integrity for improved cement interdigitation to achieve durable fixation in revision total knee arthroplasty (TKA). The purpose of this study is to review the survivorship, clinical results, and complications of revision TKA using highly porous 3-dimensionally printed titanium metaphyseal cones.

METHODS

This is a review of 62 revision TKAs using metaphyseal tibial cones, with 15 cases utilizing both tibial and femoral cones. The mean age of the patients was 66 years (range 32-84) who had a mean follow-up of 27 months (range 24-34). There were 38 women and 24 men, who had a mean body mass index of 33 (range 18.3-62).

RESULTS

Revision-free survival of the cones was 90.2%. If infection was excluded, survivorship was 100%. There were no cases of aseptic loosening. The mean Knee Society Score improved from 51 points preoperatively to 80 points at the time of latest follow-up. The mean Knee Society Functional Score improved from 48 points preoperatively to 68 points. A total of 15 of the 62 patients (24%) required additional surgery: 10 (16%) for infection, 3 (5%) for contracture, 1 for patellar subluxation, and 1 for quadriceps tendon rupture.

CONCLUSION

Metaphyseal fixation is important for survivorship in revision TKA which can be challenging due to cancellous and structural bone loss encountered at the time of revision. Prosthetic joint infection continues to be the leading cause of failure in revision TKA. The use of highly porous titanium metaphyseal cones produced from 3-dimensionally printed technology used in this study demonstrated excellent short-term results with no cases of aseptic loosening. Further follow-up is required to determine if these results can be durable over a longer period.

Survival and functional outcome of revision total knee arthroplasty with a total stabilizer knee system: minimum 5 years of follow-up

INTRODUCTION

Revision knee arthroplasty surgery can range from patella resurfacing or polyethylene exchange, to staged revision and revision to a more constrained implant. Subsequently, the ability to elicit outcomes becomes difficult to obtain and hence information on functional outcome and survivorship for all modes of failure with a single revision system is valuable.

METHODS

We retrospectively assessed 100 consecutive revision knee replacements that were converted from a primary knee replacement to a Triathlon total stabilizer (TS) knee system (Stryker Orthopaedics, Mahwah, NJ). Inclusion criteria included failure of a primary knee replacement of any cause converted to a Stryker TS knee system. Midterm outcome of at least 5 years was required. Implants survivorship, Oxford Knee Score (OKS), Forgotten Joint Score (FJS-12), Short Form (SF-) 12, reported patient satisfaction and radiographic analysis were recorded.

RESULTS

The all-cause survival rate at 5 years was 89.0% [95% confidence interval (CI) 87.3 to 90.7]. The all-cause survival rate was generally static after the first 4 years. The mean OKS was 27 (SD 11.9, range 0 to 46), FJS was 32.3 (SD 30.4, range 0 to 100), SF-12 physical component summary was 40.6 (SD 17.6, range 23.9 to 67.1), and mental component summary was 48.3 (SD 15.5, range 23.9 to 69.1). Reported patient satisfaction in patients who were not re-revised was 82%.

CONCLUSION

The midterm survivorship of cemented Stryker Triathlon TS knee revision for all-cause mode of failure is good to excellent; however, future follow-up is required to ensure this survivorship is observed into the long term. Despite limited functional outcome, overall patient satisfaction rates are high.