Management of failed UKA to TKA: conventional versus robotic-assisted conversion technique

Robotic arm-assisted conversion of unicompartmental knee arthroplasty to total knee arthroplasty

Aims

Robotic arm-assisted surgery offers accurate and reproducible guidance in component positioning and assessment of soft-tissue tensioning during knee arthroplasty, but the feasibility and early outcomes when using this technology for revision surgery remain unknown. The objective of this study was to compare the outcomes of robotic arm-assisted revision of unicompartmental knee arthroplasty (UKA) to total knee arthroplasty (TKA) versus primary robotic arm-assisted TKA at short-term follow-up.

Methods

This prospective study included 16 patients undergoing robotic arm-assisted revision of UKA to TKA versus 35 matched patients receiving robotic arm-assisted primary TKA. In all study patients, the following data were recorded: operating time, polyethylene liner size, change in haemoglobin concentration (g/dl), length of inpatient stay, postoperative complications, and hip-knee-ankle (HKA) alignment. All procedures were performed using the principles of functional alignment. At most recent follow-up, range of motion (ROM), Forgotten Joint Score (FJS), and Oxford Knee Score (OKS) were collected. Mean follow-up time was 21 months (6 to 36).

Results

There were no differences between the two treatment groups with regard to mean change in haemoglobin concentration (p = 0.477), length of stay (LOS, p = 0.172), mean polyethylene thickness (p = 0.065), or postoperative complication rates (p = 0.295). At the most recent follow-up, the primary robotic arm-assisted TKA group had a statistically significantly improved OKS compared with the revision UKA to TKA group (44.6 (SD 2.7) vs 42.3 (SD 2.5); p = 0.004) but there was no difference in the overall ROM (p = 0.056) or FJS between the two treatment groups (86.1 (SD 9.6) vs 84.1 (4.9); p = 0.439).

Conclusion

Robotic arm-assisted revision of UKA to TKA was associated with comparable intraoperative blood loss, early postoperative rehabilitation, functional outcomes, and complications to primary robotic TKA at short-term follow-up. Robotic arm-assisted surgery offers a safe and reproducible technique for revising failed UKA to TKA.

Revision Total Knee Arthroplasty With an Imageless, Second-Generation Robotic System

BACKGROUND

Robotic-assisted total knee arthroplasty is increasingly used in revision total knee arthroplasty (rTKA), with imageless systems recently receiving Food and Drug Administration (FDA) approval. However, there remains a paucity of literature on the use of robotic assistance in revision total knee arthroplasty (TKA). This paper describes the imageless surgical technique for robotic revision TKA using a second-generation robotic system and details both intraoperative and 90-day outcomes.

METHODS

This was a retrospective review of 115 robotic revision TKAs from March 2021 to May 2023 at 3 tertiary academic centers. Patient demographics, perioperative surgical data, and 90-day outcomes were collected. Pain and Patient-Reported Outcomes Measurement Information System scores preoperatively and postoperatively were recorded. All-cause reoperations at the final follow-up were detailed. The mean patient age was 65 years (range, 43 to 88), and 58% were women. The mean follow-up time was 13 months (range, 3 to 51).

RESULTS

The most common indications for rTKA were instability (n = 37, 32%) and aseptic loosening (n = 42, 37%). There were 83 rTKAs to a posterior-stabilized liner, 22 to a varus-valgus constrained liner, and 5 to a hinged construct. The median polyethylene size was 11 (interquartile range, 10 to 13), and 93% of patients had their joint line restored within 5 millimeters of the native contralateral knee. Within the 90-day postoperative window, there were 8 emergency department visits and 2 readmissions. At the final follow-up, there were 5 reoperations and 2 manipulations under anesthesia. There were 4 patients who required irrigation and debridement after superficial wound dehiscence, and one had an arthrotomy disruption after a fall.

CONCLUSIONS

This review demonstrates favorable intraoperative and 90-day outcomes and suggests that imageless robotic surgery is a promising modality in rTKA. Further studies comparing the longitudinal outcomes after robotic and conventional rTKA are warranted.

Unicompartmental knee arthroplasty revised to total knee arthroplasty versus primary total knee arthroplasty: A meta-analysis of matched studies

BACKGROUND

Unicompartmental knee arthroplasty (UKA) offers a less invasive alternative to total knee arthroplasty (TKA), but is accompanied by a high revision risk. The aim of our study was to perform a meta-analysis comparing outcomes of UKA revised to TKA versus primary TKA, to assess if UKA is an effective treatment option, despite its potential need for revision.

METHODS

Studies comparing matched cohorts of patients with UKA revised to TKA versus primary TKA were identified via the PubMed, Ovid EMBASE, and Scopus databases. The following outcome measures were compared between treatment modalities: postoperative reoperation or revision, total complications, range of motion, patient-reported outcome measures, and length of stay.

RESULTS

Ten studies were included with 1,070 patients: 410 UKA to TKA and 660 primary TKA. At an average follow-up of 5.6 years in the UKA to TKA cohort and 5.7 years in the primary TKA cohort, there were no significant difference in risk of revision (p = 0.81), total complications (p = 0.54), range of motion (p = 0.09), or length of stay (p = 0.31). Both objective and functional Knee Society Score were significantly higher in patients with primary TKA (p < 0.01). However, there was no difference in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) or pain scores (p = 0.13 and p = 0.21, respectively).

CONCLUSION

UKA revised to TKA produced comparable clinical and patient-reported outcomes to a primary TKA. UKA may be an effective treatment option in unicompartmental arthritis that would allow for improved functionality and satisfaction without the concern of outcomes deteriorating in patients where a revision becomes necessary.

No Difference in Range of Motion, Components, or Complications Following Conversion of Robotic-Assisted Total Knee Arthroplasty Compared to Manual TKA After Undergoing Manual or Robotic-Assisted Unicompartmental Knee Arthroplasty

Background

Conversion surgery from unicondylar knee arthroplasty (UKA) to total knee arthroplasty (TKA) remains a challenge due to scarring, implant/cement removal, and loss of bony landmarks. Robotic-assisted (RA) TKA may assist in challenges seen in manual conversion TKA. The aim of this study is to identify if there are differences in components and functional outcomes dependent on manual/RA primary UKA and conversion TKA.

Methods

A retrospective chart review was performed on patients undergoing conversion from UKA to TKA over a 10-year period at a single institution. Data extracted included surgical technique, reason for UKA failure, range of motion at 1 year, need for augments, and utilization of revision components.

Results

Forty-nine patients (50 knees) with a UKA converted to a TKA were divided into 4 groups based on primary and conversion surgery: manual-to-manual (n = 11), manual-to-robot (n = 11), robot-to-manual (n = 11), and robot-to-robot (n = 17). There was no difference in need for augments (P = .376), size of poly (P = .23), postoperative flexion (P = .52), or extension (P = .76) at 1 year between the 4 groups. However, patients with primary manual UKA did require significantly more augments during revision (P = .032).

Conclusions

Our study did not show any statistically significant differences of primary RA or manual UKA to RA or manual TKA in terms of range of motion at 1 year, complications, or differences in components. RA conversion from UKA to TKA is a new but equivalent technique to manual conversion. Primary surgery may impact the requirement for augments during conversion surgery.

Conversion of Patellofemoral Arthroplasty to Robotic-Assisted Total Knee Arthroplasty

Conversion of patellofemoral arthroplasty to total knee arthroplasty (TKA) has been described as similar to primary TKA, although it may come with more challenges and worse outcomes. With the increased rate of revision following conversion TKA vs primary TKA, robotically assisted TKA provides an alternative technique to manual conversion. We present 3 cases of robot-assisted conversion of prior patellofemoral arthroplasty to TKA with good mechanical and clinical outcomes and no intraoperative complications.

Robotic-Assisted Conversion of a Failed Medial Unicompartmental Knee Arthroplasty to Total Knee Arthroplasty: A Case Report

CASE

An 81-year-old man with a history of left medial unicompartmental knee arthroplasty (mUKA) 8 years prior presented to the outpatient clinic with gradually increasing medial left knee pain of 6 years of duration. He underwent left conversion robotic-assisted total knee arthroplasty (RA TKA). At 1-year follow-up, the patient reported satisfactory clinical outcomes and excellent component alignment on x-rays.

CONCLUSION

This case highlights using RA TKA for failed mUKA as a viable and promising conversion arthroplasty alternative technique that may improve surgical outcomes by enhancing implant alignment and positioning, protecting the soft tissues, and preserving bone stock.

Surgical Technique: Robotic-Assisted 1.5-Stage Exchange Total Knee Arthroplasty for Periprosthetic Joint Infection

A 1.5-stage exchange total knee arthroplasty for periprosthetic joint infection has been described; however, achieving a balanced and well-aligned construct can sometimes be difficult given the bony defects often encountered in these cases. The use of robotic navigation technologies allows for accurate and precise implant placement. This technique report details the utilization of robotic navigation in a 1.5-stage exchange total knee arthroplasty for periprosthetic joint infection and describes the outcome of 6 patients. This technique guide highlights how robotic technology can account for many commonly encountered bone voids, joint line identification, and component orientation, while achieving a balanced and well-aligned knee.

[Market overview: Robotic-assisted arthroplasty : Current robotic systems, learning curve and cost analysis]

Robotic-assisted arthroplasty has been rapidly entering clinical routine in recent years. The leading endoprosthesis manufacturers have all meanwhile placed robotic systems on the market, which, however, differ significantly from one another technically. Current systems are currently classified according to the degree of autonomy (active vs. semi-active vs. passive) and the data/image source (image-based: CT vs. X‑ray, imageless). Some systems already offer the possibility of robotic-assisted or navigated implantation of hip endoprostheses. In the following review article, the currently leading robotic systems will be presented and compared with regard to their characteristics. Furthermore, the analysis of the learning curves for the different systems, currently available cost analysis models and an outlook on future developments and challenges will be given.

Revision Total Knee Arthroplasty Using Robotic Arm Technology

Total knee arthroplasty (TKA) is a highly successful operation for the treatment of end-stage osteoarthritis of the knee. Increasing use of computer-assisted and robotic-assisted total joint arthroplasty has been shown to improve component position, with short-term studies demonstrating improved survivability in unicompartmental knee arthroplasty. Robotic-assisted technology has been shown to be helpful in revising unicompartmental knee arthroplasty to TKA, as well as hip fusion to total hip arthroplasty, but few have described revision of a primary TKA. This case report describes the use of robotic-assisted technology in revision TKA. Robotic assistance during revision TKA may improve component alignment and increase prosthesis longevity. Future research is needed to investigate the effects on survivorship and cost.

Imageless robotic-assisted revision arthroplasty from UKA to TKA : Surgical technique and case-control study compared with primary robotic TKA

Background and objective

It is evident from the national joint registries that numbers of revision knee arthroplasty operations are rising. The aim of this article is to introduce a new robotic-assisted approach in UKA to TKA revision arthroplasty and investigate the alignment accuracy, implant component use and surgery time and to compare it to primary robotic-assisted TKA arthroplasty.

Methods

This retrospective, case-control study included patients undergoing image-less robotic-assisted revision arthroplasty from UKA to TKA (n = 20) and patients undergoing image-less robotic-assisted primary TKA (control group, n = 20) from 11/2018 to 07/2020. The control group was matched based on the BMI and natural alignment. Comparison of groups was based on postoperative alignment, outlier rate, tibial insert size, lateral bone resection depth, incision-to-wound closure time. All surgeries were performed by a single senior surgeon using the same bi-cruciate stabilizing TKA system. Statistical analysis consisted of parametric t‑testing and Fisher’s exact test with a level of significance of p < 0.05.

Results

The two groups showed no differences in mean BMI, natural alignment (p > 0.05) and mean overall limb alignment. No outlier was found for OLA and slope analysis. The smallest insert size (9 mm) was used in 70% of the cases in the revision group (n = 14) and in 90% of the cases in the primary group (n = 18, p = 0.24), distal femoral and tibial resection depth showed no statistical difference (p > 0.05). The incision to wound closure time was longer in the revision group but showed no significant difference.

Conclusion

Image-less robotic-assisted revision arthroplasty from UKA to TKA showed a comparable surgery time, and alignment accuracy in comparison to primary robotic-assisted TKA. Comparable bone preservation and subsequent tibial insert size use was observed for both groups.