Results of a Modular Revision System in Total Knee Arthroplasty

Global mapping of institutional and hospital-based (Level II-IV) arthroplasty registries: a scoping review

PURPOSE

Four joint arthroplasty registries (JARs) levels exist based on the recorded data type. Level I JARs are national registries that record primary data. Hospital or institutional JARs (Level II-IV) document further data (patient-reported outcomes, demographic, radiographic). A worldwide list of Level II-IV JARs must be created to effectively assess and categorize these data.

METHODS

Our study is a systematic scoping review that followed the PRISMA guidelines and included 648 studies. Based on their publications, the study aimed to map the existing Level II-IV JARs worldwide. The secondary aim was to record their lifetime, publications' number and frequency and recognise differences with national JARs.

RESULTS

One hundred five Level II-IV JARs were identified. Forty-eight hospital-based, 45 institutional, and 12 regional JARs. Fifty JARs were found in America, 39 in Europe, nine in Asia, six in Oceania and one in Africa. They have published 485 cohorts, 91 case-series, 49 case-control, nine cross-sectional studies, eight registry protocols and six randomized trials. Most cohort studies were retrospective. Twenty-three per cent of papers studied patient-reported outcomes, 21.45% surgical complications, 13.73% postoperative clinical and 5.25% radiographic outcomes, and 11.88% were survival analyses. Forty-four JARs have published only one paper. Level I JARs primarily publish implant revision risk annual reports, while Level IV JARs collect comprehensive data to conduct retrospective cohort studies.

CONCLUSIONS

This is the first study mapping all Level II-IV JARs worldwide. Most JARs are found in Europe and America, reporting on retrospective cohorts, but only a few report on studies systematically.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020196922.

A complex TKA in a post-traumatic arthritic knee with a significant bone loss: A case report and literature review

INTRODUCTION

Total knee arthroplasty is an effective procedure that aims at restoring function and relieving pain. While most surgeons are familiar with primary TKA, some secondary cases are unique and might create a challenge.

CASE PRESENTATION

A young 30-year-old male with no comorbidities had a gunshot injury to his knee. He developed knee arthritis later, which was treated with modular TKA and a cement-screws technique for substitution for bone loss.

DISCUSSION

Complex cases of TKA demand innovative solutions, many options exist now for dealing with various challenges, but they are expensive and not always available, so other choices must be utilized to afford the best possible outcome.

CONCLUSION

Post-traumatic TKA could be technically challenging, and screws buttressing the cement could effectively handle bone defects when other options are unavailable.

Bone loss in aseptic revision total knee arthroplasty: management and outcomes

Background

Although several techniques and implants have been developed to address bone loss in revision total knee arthroplasty (rTKA), management of these defects remains challenging. This review article discusses the indications and management options of bone loss following total knee arthroplasty based on preoperative workup and intraoperative findings.

Main text

Various imaging modalities are available that can be augmented with intraoperative examination to provide a clear classification of a bony defect. For this reason, the Anderson Orthopaedic Research Institute (AORI) classification is frequently used to guide treatment. The AORI provides a reliable system by which surgeons can classify lesions based on their size and involvement of surrounding structures. AORI type I defects are managed with cement with or without screws as well as impaction bone grafting. For AORI type IIA lesions, wedge or block augmentation is available. For large defects encompassing AORI type IIB and type III defects, bulk allografts, cones, sleeves, and megaprostheses can be used in conjunction with intramedullary stems.

Conclusions

Treatment of bone loss in rTKA continues to evolve as different techniques and approaches have been validated through short- and mid-term follow-up. Extensive preoperative planning with imaging, accurate intraoperative evaluation of the bone loss, and comprehensive understanding of all the implant options available for the bone loss are paramount to success.

Impact of resident involvement on complication rates in revision total knee arthroplasty

Objectives

The number of revision total knee arthroplasty (TKA) procedures continues to rise, a direct consequence of the increase in primary TKA. The number of arthroplasty-trained orthopaedic surgeons has failed to increase at a corresponding rate, and the increased burden will ultimately fall on non-specialized orthopaedists. Resident involvement in primary TKA has not been found to increase postoperative complications, but revision TKA is more complex and the impact of resident involvement has not been well studied.

Methods

Using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database, this study identified 1834 revision TKA procedures between the years 2008 and 2012. Of these procedures, 863 included resident involvement. Demographic information, comorbidities, operative times, length of stay (LOS), and 30-day postoperative complications were stratified by resident and non-resident involvement and analyzed.

Results

Resident involvement was not associated with a significant increase in short-term complications. Operative times were significantly longer with resident involvement (147.50 min with resident involvement vs. 124.55 min without a resident, p < 0.001). Length of stay after procedures with resident involvement was higher by 0.34 days, but this did not reach significance (p = 0.061).

Conclusion

Resident involvement in revision total knee arthroplasty was associated with a significant increase in operative time; however, there were no significant increases in postoperative complication rates within 30 days. These findings support continued resident involvement in revision total knee arthroplasty cases and postoperative management.

Mid-term results of complex primary total knee arthroplasty using a rotating-hinge implant

BACKGROUND

The indications and outcomes of semi- or fully-constrained knee implants in primary total knee arthroplasty (TKA) are still controversially discussed. The present study aims to evaluate the mid-term results and complications of a modular/non-modular rotating-hinge implant in complex primary TKA.

METHODS

Eighty-two patients (86 knees) following primary TKA were retrospectively evaluated with a mean follow-up of 63 months. The functional outcome was assessed using the American Knee Society Score (AKSS) and the Oxford Knee Score (OKS). A Visual Analog Scale (VAS) was used to determine pain levels. Implant survival and reoperation rateswere estimated using competing risk analysis. Cox regression analysis wasperformed to evaluate the influence of modularity on implant survival.

RESULTS

The survival rate with the endpoint implant revision was 90% (95 %CI:83-98%) and the survival rate with the endpoint all reoperations was 84% (95 %CI:75-94%) at 7 years. The AKSS improved significantly from 24 (SD 14.9, range:0-69) preoperatively to 83 (SD 14.3, range:57-100) postoperatively (p < 0.001); functional AKSS improved significantly from 27 (SD 24.3, range:0-100) to 46 (SD: 32.9, range 0-100) (p = 0.003), and OKS from 19 (SD: 8.3, range:5-43) to 29 (SD: 10.7, range:6-48), respectively (p < 0.0001). VAS decreased significantly from 8 (SD: 2.6, range:0-10) preoperatively to 3 (SD: 2.9, range:0-9) postoperatively (p < 0.0001). There was no significant influence of modularity on revision rates comparing modular to non-modular implants (p = 0.072).

CONCLUSIONS

The present rotating-hinge implant provides substantial improvement in function and reduction of pain with good implant survival in the mid-term. Modularity was not associated with higher rates of revision.

Factors Affecting Range of Motion After Revision Total Knee Arthroplasty

BACKGROUND

Range of motion (ROM) after revision total knee arthroplasty (RTKA) is an important clinical outcome, as decreased ROM can lead to patient dissatisfaction and diminished mobility. This study sought to determine the effect of type of revision, implant constraint level, and reason for revision has on RTKA ROM.

METHODS

A retrospective review of 832 RTKA cases from 2011 to 2019 was conducted at a single, urban academic institution. Patients who underwent aseptic RTKA and had preoperative and 1-year postoperative ROM in their chart were included. The ΔROM was calculated by subtracting the preoperative ROM from the 1-year postoperative ROM. ROM was compared between tibial polyethylene liner-only revisions (liner) and all other revision types (component) and based on reason for revision. Subanalysis was performed within the liner and component revision cohorts to determine the effect of reason for revision and implant constraint level on ROM.

RESULTS

In total, 290 patients qualified. Forty-two patients had liner revisions (14.5%) and 248 had component revisions (85.5%). The ΔROM for component revision cases was significantly higher than liner exchange only (10° ± 24° vs.1° ± 19°; P = .03). ΔROM was not significant when comparing the level of implant constraint nor was it when separating and comparing by type of revision. Component revisions due to instability were found to significantly decrease ΔROM.

CONCLUSION

Component revision cases have significantly improved ΔROM when compared with liner-only revision. Constraint level is not significantly associated with changes in ROM in either liner or component revisions. Component revisions due to instability significantly reduce ΔROM.

Mid-level constraint may correct coronal plane imbalance without compromising patient function in patients with severe osteoarthritis

Introduction

Mid-level constraint (MLC) in Total Knee Arthroplasty (TKA) offer surgeons the opportunity to obtain a well-balanced varus-valgus balance in the setting of slight ligament imbalance. As such, we sought to evaluate patient reported outcome measures (PROMs), alignment correction, and rate of revision between the MLC group and a cohort of posterior stabilized (PS) knees in a cohort of patients with preoperative degenerative arthritis.

Materials/methods

We performed a retrospective review of 57 MLC knees and 96 PS knees from a single manufacturer that were implanted by a single surgeon. We found the average age (68.91 vs. 68.40, p = 0.72), average BMI (30.88 vs. 29.14, p = 0.10), and gender breakdown (25:32 vs. 28:69, p = 0.08) to be comparable between the two cohorts. The latest follow-up was 4.0 years in the MLC group and 3.8 years in the PS group, p = 0.26.

Results

The two cohorts inherently resulted in significantly different preoperative deformities (MCL knees: average varus deformity 13.75°, average valgus deformity 12.37°; PS knees average varus deformity 15.14°, average valgus deformity 10.8°). There were more valgus knees in the MLC group (36 vs. 22 (p < 0.001), respectively), but the postoperative alignment was the same. MLC cohort: preoperative varus group had 4.74° of valgus postoperatively, preoperative valgus group had 5.43° of valgus postoperatively. PS cohort: preoperative varus group had 5.40° of valgus postoperatively, preoperative valgus group had 4.80° of valgus postoperatively. We found a significant difference in Knee Injury and Osteoarthritis Outcome Score (KSCRS-Total) between the two groups (MLC 163.9 vs. PS 132.8, p = 0.003). There was no significant difference in terms of Range of Motion (ROM) (MLC 121° vs. PS 122°, p = 0.58), anterior knee pain (MLC 1.75 vs. PS 1.81, p = 0.39), or Pain VAS (MLC 25.1 vs. PS 28.6, p = 0.46). There was similar rate of revision between the cohorts (3.5% MLC vs. 2.10% PS, p = 0.13). There was no significant difference in manipulation rate (8.78% MLC vs. 9.40% PS, p = 0.38).

Conclusion/discussion

This study demonstrated that the use of MLC in TKA allows surgeons to correct preoperative deformities with equal or improved functional outcomes compared to PS knees. In general, we recommend that surgeons try to balance the knee and use the least amount of constraint possible but should consider MLC when needed and use such implants if they are unable to balance the varus-valgus gap.

Stem Fixation in Revision Total Knee Arthroplasty: Indications, Stem Dimensions, and Fixation Methods

Although stems improve initial mechanical stability in revision total knee arthroplasty (TKA), ideal indications, proper lengths and diameters, and appropriate fixation methods remain controversial. The topics of the present article include the indications, selection of lengths and diameters, and fixation methods of stems in revision TKA. The use of a stem in revision TKA can protect the juxta-articular bone. A stem cannot be a substitute for optimal component fixation; it plays an adjunctive role in transferring the loads from the compromised metaphysis to the stronger diaphysis. Proper bone surface preparation and appropriate use of the stem based on a great store of knowledge are required to support the stemmed components effectively in revision TKA. The balance between overshielding and overloading the juxta-articular bone would provide excellent structural protection. The stem length and diameter should be tailored according to patients’ anatomical characteristics and determined fixation strategy. There are two traditional methods of stem fixation including the total cementation technique and the hybrid technique with a cementless press-fit stem. Selection of a cementation technique should be based on thorough consideration of advantages and disadvantages of each technique.

Revision of Unicompartmental Knee Arthroplasty to Total Knee Arthroplasty: Is It as Good as a Primary Result?

BACKGROUND

Unicompartmental knee arthroplasty (UKA) is touted as a more conservative, bone- and tissue-sparing procedure than total knee arthroplasty (TKA). Similarly, revision of UKA to TKA is generally a simpler procedure than revision of TKA to TKA and can be accomplished with primary TKA components in most cases. The purpose of this study was to review a consecutive series of patients undergoing revision of failed UKA to TKA to determine if etiology is similar to that reported in recent literature and evaluate if the results align more with primary TKA vs revision of TKA to TKA.

METHODS

A query of our private practice registry from 1996 to 2015 revealed 184 patients (193 knees) who underwent revisions of failed UKA with minimum 2-year follow-up. The mean age was 63.5 (37-84) years, body mass index was 32.3 (19-57) kg/m², and interval after UKA was 4.8 (0-35) years. The most prevalent indications for UKA revision were aseptic loosening (42%) arthritic progression (20%), and tibial collapse (14%).

RESULTS

At 6.1-year mean follow-up (2-20), 8 knees (4.1%) required re-revision, which is similar to what we reported at 5.5 years in a group of primary TKA patients (6 of 189; 3.2%) and much lower than what we observed at 6.0 years in a recent study of aseptic revision TKA patients (35 of 278; 12.6%). In the study group, Knee Society clinical and function scores improved from 50.8 and 52.1 preoperatively to 83.4 and 67.6 at the most recent evaluation. Re-revisions were for aseptic loosening (3), instability (2), arthrofibrosis (2), and infection (1).

CONCLUSIONS

Compared to published individual institution and national registry data, re-revision rates of failed UKA are equivalent to revision rates of primary TKA and substantially better than re-revision rates of revision TKA. These data should be used to counsel patients undergoing revision UKA to TKA.