Short-term outcomes of robotically assisted patello-femoral arthroplasty

Return to Sports in Patients Aged 50 Years or Younger After Robotic-Assisted Patellofemoral Arthroplasty: A 10-Year Experience Reporting High Clinical Benefits and High Patient Satisfaction With Return to an Active Lifestyle

BACKGROUND

Limited data are available on return to sports and patient psychometric ratings of success after patellofemoral arthroplasty (PFA) in younger patients with high expectations to return to an active lifestyle.

PURPOSE/HYPOTHESIS

The purpose of this article was to determine the role of PFA and its success in meeting patient expectations regarding the return to low-impact recreational sports and an active lifestyle in younger, active patients. It was hypothesized that PFA would allow younger patients to return to low-impact sports and an active lifestyle and achieve high patient psychometric ratings.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

In this 10-year prospective study (2009-2018), robotic-assisted PFA was performed on 44 patients (32 women and 12 men; n = 51 consecutive knees), with a mean age of 37.2 years (range, 21-50 years). The follow-up rate was 98%, with a mean of 5.3 years (range, 2-9.3 years). Primary clinical outcomes were as follows: the validated Cincinnati Knee Rating System sports activity and symptom rating scales, patient psychometric ratings of the substantial clinical benefit (SCB), and the Patient Acceptable Symptom State (PASS). Secondary outcomes were the Cincinnati Knee Rating System occupational rating, visual analog pain scale, and the 12-Item Short Form Health Survey. Survivorship was defined by conversion to total knee replacement (TKR).

RESULTS

Before PFA, 78% of patients (35/45 knees) were symptomatic and unable to perform recreational sports, with only 20% of patients (9/45 knees) performing some low-impact sports. After PFA, 80% of patients (36/45 knees) were able to perform low-impact sports, and 7% (3/45 knees) performed jumping-pivoting sports (P < .001). The SCB scored by the patient showed 87% of knees as good, very good, or normal. On the PASS analysis, 89% of patients (95% CI, 76%-96%) were "pleased," and 93% (95% CI, 82%-99%) would undergo surgery again. There were clinically relevant improvements in symptoms of pain, swelling, and giving way (P = .0001). Preoperatively, 91% of knees had moderate to severe pain with activities of daily living, and only 11% of knees had pain at the follow-up. Five of the 50 knees (10%) underwent TKR conversion with one patient lost to follow-up.

CONCLUSION

PFA resulted in a high return of patients to low-impact sports with high SCB and PASS psychometric ratings. The robotic-assisted 3-dimensional preoperative planning allowed precise intraoperative trochlear implant alignment in knees with severe trochlear dysplasia. PFA is recommended as an alternative treatment in younger patients with end-stage symptomatic patellofemoral arthritis.

REGISTRATION

NCT02738476 (ClinicalTrials.gov identifier).

Patellofemoral Arthroplasty

Patellofemoral arthroplasty (PFA) as a treatment option for isolated patellofemoral disease continues to evolve. Enhancement in patient selection, surgical technique, implant design, and technology has led to improved short-term and midterm outcomes. Furthermore, in the setting of a younger patient with isolated patellofemoral arthritis, PFA represents an option for improved function with faster recovery times, bone preservation, maintenance of ligamentous proprioception, and the ability to delay total knee arthroplasty (TKA). The most common reason for revising PFA to a TKA is progression of tibiofemoral arthritis. In general, conversion of PFA to TKA leads to successful outcomes with minimal bone loss and the ability to use primary TKA implants and instrumentation. PFA seems to be a cost-effective alternative to TKA in appropriately selected patients with 5-, 10-PFA survivorships of 91.7% and 83.3%, respectively, and an annual revision rate of 2.18%; however, more long-term clinical studies are needed to determine how new designs and technologies affect patient outcomes and implant performance.

Modern Patellofemoral Arthroplasty

INTRODUCTION

The ideal procedure for isolated patellofemoral arthritis is a controversial topic. Patellofemoral arthroplasty (PFA) is an option that aims to restore normal kinematics to the knee while preserving bone. PFA has been shown to have benefits compared with total knee arthroplasty (TKA) in this patient population but has historically had a high failure rate. Revision rates are improving with modern implants and tight indications but still remain higher than TKA. This review summarizes current thinking around PFA using modern implants and techniques in 2023, provides an implant-specific analysis, and assesses how we can improve outcomes after PFA based on the current literature. The aim was to provide an outline of the evidence around PFA on which surgeons can make decisions to optimize patient outcome in this young and active population.

METHODS

Four databases (MEDLINE, Embase, Scopus, and SPORTDiscus) were searched for concepts of patellofemoral joint arthroplasty. After abstract and text review, a screening software was used to assess articles based on inclusion criteria for studies describing indications, outcomes, and techniques for isolated PFA using modern implants, with or without concomitant procedures.

RESULTS

A total of 191 articles were included for further examination, with 62 articles being instructional course lectures, systematic reviews, technique articles, narrative reviews, expert opinions, or meta-analyses. The remaining articles were case reports, trials, or cohort studies. Articles were used to create a thorough outline of multiple recurrent topics in the literature.

CONCLUSIONS

PFA is an appealing option that has the potential to provide a more natural feeling and functioning knee for those with isolated PF arthritis. The high rate of revision is a cause for concern and there are several technical details that should be stressed to optimize results. The uncertain outcome after revision to TKA also requires more investigation. In addition, the importance of strict selection criteria and firm indications cannot be stressed enough to optimize longevity and attempt to predict those who are likely to have progression of tibiofemoral osteoarthritis. The development of new third-generation implants is promising with excellent functional outcomes and a much lower rate of maltracking and implant complications compared with earlier generations. The impact of these implants and improvement in surgical techniques on the revision rate of PFA will be determined from longer-term outcomes.

Patellofemoral Arthroplasty Is an Efficient Strategy for Isolated Patellofemoral Osteoarthritis with or without Robotic-Assisted System

There is relative paucity in the literature concerning outcomes after robotic-assisted Patellofemoral Arthroplasty (PFA). The aims were (1) to evaluate outcomes in patients undergoing PFA with inlay or onlay components, with or without robotic arm assistance and (2) to identify risk factors of poor outcomes after PFA. This retrospective study included 77 PFA for isolated patellofemoral joint osteoarthritis, assigned to three groups (18 conventional technique, 17 image-free robotic-assisted system and 42 image-based robotic-assisted system). The demographic data were comparable between the three groups. The clinical outcomes assessed were: Visual Analogue Scale, Knee Society Score, Kujala score and satisfaction rate. The radiological measures were: Caton Deschamps index, patellar tilt and frontal alignment of the trochlea. Functional outcomes, satisfaction rate and residual pain were comparable between the three groups. Patellar tilt improvement was superior when a robotic device was used (either image-based or image-free) compared to the conventional technique. There were three revisions (3.9%) at the last follow-up related to femorotibial osteoarthritis progression. Multivariate analysis found no significant risk factors for poor outcomes, with respect to the surgical technique or implant design. Functional outcomes and revisions rate after PFA were comparable between the surgical techniques and implants. Robotic-assisted systems were associated with a superior improvement of the patellar tilt compared to the conventional technique.

Knee arthroplasty utilization trends from 2010 to 2019

BACKGROUND

Interest in partial knee arthroplasty procedures including unicompartmental arthroplasty (UKA), patellofemoral arthroplasty (PFA), and bicompartmental knee arthroplasty (BKA) has increased due to their bone and ligament preservation compared to total knee arthroplasty (TKA). Implant designs, changing thoughts on appropriate indications for partial knee arthroplasty, and availability of navigation also impacted the field over the last decade. The aims of this study were to evaluate trends over the last decade in utilization of 1) partial and total knee arthroplasty; and 2) computer-assistance in knee arthroplasty.

METHODS

A retrospective cohort analysis was conducted using the PearlDiver database. Patients who underwent PFA, UKA, BKA, and TKA for an indication of osteoarthritis (OA) were identified using Current Procedural Terminology (CPT) codes. Trends analysis from 2010 to 2019 was conducted to compare utilization based on procedure type and computer-assistance. Statistical analysis was conducted using Compounded Annual Growth Rates (CAGR) and linear regression.

RESULTS

From 2010 to 2019, there was a significant decrease in utilization of PFA (CAGR: -5.73 %; p = 0.011) and BKA (CAGR: -10.49 %; p = 0.013), but no significant difference in that of UKA (p = 0.224) and TKA (p = 0.421). There was a significant increase in the utilization of computer assistance for both UKA (CAGR: +19.81 %; p = 0.002) and TKA (CAGR: +3.90 %; p = 0.038), but there was no significant difference for computer-assisted PFA (p = 0.724) and BKA (p = 0.951).

CONCLUSIONS

TKA is still the most common arthroplasty procedure for OA. Decreased utilization of PFA and BKA may be explained by reported failure and revision rates for PFA and BKA compared to TKA.

Robotic-Assisted Patellofemoral Replacement-Correlation of Preoperative Planning with Intraoperative Implant Position and Early Clinical Experience: A Minimum 2-Year Follow-up

Patello-femoral arthroplasty (PFA) is successful in a selected group of patients and yields a good functional outcome. Robotic-assisted knee arthroplasty has been shown to provide better implant positioning and alignment. We aim to report our early outcomes and to compare Mako's (Robotic Arm Interactive Orthopaedic System [RIO]) preoperative implant planning position to our intraoperative PFA implant position. Data for this study was prospectively collected for 23 (two bilateral) patients who underwent robotic-assisted PFA between April 2017 and May 2018. All preoperative implant position planning and postoperative actual implant position were recorded. Presence of trochlear dysplasia and functional outcome scores were also collected. There were 17 (two bilateral) female and 6 male patients with a mean age of 66.5 (range: 41-89) years. The mean follow-up period was 30 (range: 24-37) months. Eighteen knees (72%) had evidence of trochlear dysplasia. The anterior trochlear line was on average, 7.71 (range: 3.3-11.3) degrees, internally rotated to the surgical transepicondylar axis and on average 2.9 (range: 0.2-6.5) degrees internally rotated to the posterior condylar line. The preoperative planning range was 4-degree internal to 4-degree external rotation, 4-degree varus to 6-degree valgus, and 7-degree flexion to 3-degree extension. The average difference between preoperative planning and intraoperative implant position was 0.43 degrees for rotation (r = 0.93), 0.99 degrees for varus/valgus (r = 0.29), 1.26 degrees for flexion/extension (r = 0.83), and 0.34 mm for proudness (r = 0.80). Six patients (24%) had a different size component from their preoperative plan (r = 0.98). The mean preoperative Oxford Knee Score (OKS) was 16 and the mean postoperative OKS was 42. No patient had implant-related revision surgery or any radiological evidence of implant loosening at final follow-up. Our early results of robotic PFA are promising. Preoperative Mako planning correlates closely with intraoperative implant positioning. Longer follow-up is needed to assess long-term patient outcomes and implant survivorship.

Patellofemoral arthroplasty: expert opinion

Isolated patellofemoral osteoarthritis (PFOA) is a common cause of anterior knee pain in patients over the age of 40 years. Patellofemoral arthroplasty (PFA) is an option to address PFAO when the non-operative or joint preserving management has failed.The goals of PFA are to reduce pain and increase function of the knee in a bone and ligament preserving fashion while maintaining or optimizing its kinematics. Over the last decades advances have been made in optimizing implants designs, addressing complications and improving functional and patient reported outcomes. Appropriate patient selection has proven to be imperative. Proper surgical technique and knowledge of pearls and pitfalls is essential.The indications and surgical technique for patellofemoral arthroplasty will be reviewed here.Level of evidence: Therapeutic Level V.

New Technologies in Knee Arthroplasty: Current Concepts

Total knee arthroplasty (TKA) is an effective treatment for severe osteoarthritis. Despite good survival rates, up to 20% of TKA patients remain dissatisfied. Recently, promising new technologies have been developed in knee arthroplasty, and could improve the functional outcomes. The aim of this paper was to present some new technologies in TKA, their current concepts, their advantages, and limitations. The patient-specific instrumentations can allow an improvement of implant positioning and limb alignment, but no difference is found for functional outcomes. The customized implants are conceived to reproduce the native knee anatomy and to reproduce its biomechanics. The sensors have to aim to give objective data on ligaments balancing during TKA. Few studies are published on the results at mid-term of these two devices currently. The accelerometers are smart tools developed to improve the TKA alignment. Their benefits remain yet controversial. The robotic-assisted systems allow an accurate and reproducible bone preparation due to a robotic interface, with a 3D surgical planning, based on preoperative 3D imaging or not. This promising system, nevertheless, has some limits. The new technologies in TKA are very attractive and have constantly evolved. Nevertheless, some limitations persist and could be improved by artificial intelligence and predictive modeling.

Minimally Invasive Robotic-Assisted Patellofemoral Arthroplasty

Isolated patellofemoral arthritis is a common debilitating condition in adults older than 40 years of age. Surgical options such as patellofemoral arthroplasty exist for those who failed to respond to nonoperative treatment. However, early patellofemoral arthroplasty techniques often resulted in poor outcomes due to mal-tracking and malalignment of components. Robotic-assisted surgery recently has been introduced as an alternative to classic patellofemoral arthroplasty, with the potential to improve the anatomical fit and reproducibility of implant positioning. We present the technique for minimally invasive robotic-assisted patellofemoral arthroplasty system.

Mid-term survivorship and patient-reported outcomes of robotic-arm assisted partial knee arthroplasty

Aims

Limited evidence is available on mid-term outcomes of robotic-arm assisted (RA) partial knee arthroplasty (PKA). Therefore, the purpose of this study was to evaluate mid-term survivorship, modes of failure, and patient-reported outcomes of RA PKA.

Methods

A retrospective review of patients who underwent RA PKA between June 2007 and August 2016 was performed. Patients received a fixed-bearing medial or lateral unicompartmental knee arthroplasty (UKA), patellofemoral arthroplasty (PFA), or bicompartmental knee arthroplasty (BiKA; PFA plus medial UKA). All patients completed a questionnaire regarding revision surgery, reoperations, and level of satisfaction. Knee Injury and Osteoarthritis Outcome Scores (KOOS) were assessed using the KOOS for Joint Replacement Junior survey.

Results

Mean follow-up was 4.7 years (2.0 to 10.8). Five-year survivorship of medial UKA (n = 802), lateral UKA (n = 171), and PFA/BiKA (n = 35/10) was 97.8%, 97.7%, and 93.3%, respectively. Component loosening and progression of osteoarthritis (OA) were the most common reasons for revision. Mean KOOS scores after medial UKA, lateral UKA, and PFA/BiKA were 84.3 (SD 15.9), 85.6 (SD 14.3), and 78.2 (SD 14.2), respectively. The vast majority of the patients reported high satisfaction levels after RA PKA. Subgroup analyses suggested tibial component design, body mass index (BMI), and age affects RA PKA outcomes. Five-year survivorship was 98.4% (95% confidence interval (CI) 97.2 to 99.5) for onlay medial UKA (n = 742) and 99.1% (95% CI 97.9 to 100) for onlay medial UKA in patients with a BMI < 30 kg/m2 (n = 479).

Conclusion

This large single-surgeon study showed high mid-term survivorship, satisfaction levels, and functional outcomes in RA UKA using metal-backed tibial onlay components. In addition, favourable results were reported in RA PFA and BiKA. Cite this article: Bone Joint J 2020;102-B(1):108–116

The effectiveness of robotic hip and knee arthroplasty on patient-reported outcomes: A systematic review and meta-analysis

PURPOSE

The purpose of the study is to determine the effectiveness of semi-active and active robotic hip and knee arthroplasty on post-operative patient-reported outcomes of function, pain, quality of life and satisfaction with surgery.

METHODS

PubMed, Medline, Embase and CENTRAL were searched. Included were comparative studies investigating the effectiveness of semi-active or active robotic hip or knee arthroplasty compared to any other surgical intervention on function, pain, quality of life and satisfaction with surgery. Risk of bias and the strength of the evidence were assessed using the Downs and Black tool and the GRADE system, respectively. Relative risks, mean differences and 95% CI were calculated using random-effects models.

RESULTS

Fourteen studies involving 1342 patients were included. All studies compared robotic to conventional surgery, with active robotic surgery evaluated in total hip or knee arthroplasty and semi-active robotic surgery in total hip or unicompartmental knee arthroplasty. Most studies presented some risk of bias, and the strength of evidence was rated as low to very low quality. Random-effects meta-analyses showed that post-operative functional outcomes were comparable between active robotic and conventional total hip and knee arthroplasty at the short-, medium- and long-term follow-up. No significant difference in pain, quality of life and satisfaction with surgery were reported in individual studies.

CONCLUSIONS

This systematic and meta-analyses indicates that functional outcomes for patients undergoing active robotic total hip and knee arthroplasty were comparable to conventional surgery. Whether semi-active or active robotic hip or knee arthroplasty is effective in improving post-operative pain, quality of life and satisfaction with surgery is unclear. PROSPERO Registration Number: CRD42017059932.

Inadequacy of computed tomography for pre-operative planning of patellofemoral arthroplasty

PURPOSE

To evaluate the accuracy of preoperative planning for patellofemoral arthroplasty (PFA) by comparing: (1) virtual implant positioning simulated on pre-operative images versus (2) real implant positioning from post-operative images.

METHODS

The authors prospectively studied 15 patients that received a PFJ implant (Tornier, Montbonnot France). A pre-operative planning software was established to determine the size and position of the trochlear component. Pre-operative scans were used to perform virtual implantations by two different operators, which were then compared to the post-operative scans to calculate errors (ε) in implant positioning and intra-class correlation coefficients (ICC) for intra- and inter-observer repeatability.

RESULTS

Analysis was performed for 13 patients, for whom agreement between virtual and real surgery was excellent for anteroposterior (AP) position (ICC = 0.84; ε _max = 3.5 mm), fair for proximodistal (PD) position (ICC = 0.50; ε _max  = 9.5 mm), and poor for mediolateral (ML) position (ICC = 0.07; ε _max = 9.0 mm). It was fair for flexum-recurvatum (FR) alignment (ICC = 0.53; ε _max = 8.2°), poor for varus-valgus (VV) alignment (ICC = 0.34; ε _max = 10.0°), and internal-external (IE) rotation (ICC = 0.34; ε _max = 10.6°).

CONCLUSIONS

Pre-operative planning was insufficiently accurate to follow intra-operatively, the greatest errors being angular alignment (VV and FR). The clinical relevance of these findings is that PFA is difficult to plan pre/operatively due to non-visibility of cartilage on CT scans and to trochlear dysplasia in most cases.

LEVEL OF EVIDENCE

Prospective evaluation of operative tools on consecutive patients, Level III.

Robotics in trauma and orthopaedics

Recent advances and review of literature

Survivorship and functional outcomes of patellofemoral arthroplasty: a systematic review

PURPOSE

Historically poor results of survivorship and functional outcomes of patellofemoral arthroplasty (PFA) have been reported in the setting of isolated patellofemoral osteoarthritis. More recently, however, fairly good results of PFA were reported, but the current status of PFA outcomes is unknown. Therefore, a systematic review was performed to assess overall PFA survivorship and functional outcomes.

METHODS

A search was performed using PubMed, Embase and Cochrane systems, and the registries were searched. Twenty-three cohort studies and one registry reported survivorship using Kaplan-Meier curve, while 51 cohort studies reported functional outcomes of PFA.

RESULTS

Twelve studies were level II studies, while 45 studies were level III or IV studies. Heterogeneity was mainly seen in type of prosthesis and year the cohort started. Nine hundred revisions in 9619 PFAs were reported yielding 5-, 10-, 15- and 20-year PFA survivorships of 91.7, 83.3, 74.9 and 66.6 %, respectively, and an annual revision rate of 2.18. Functional outcomes were reported in 2587 PFAs with an overall score of 82.2 % of the maximum score. KSS and Knee Function Score were 87.5 and 81.6 %, respectively.

CONCLUSION

This systematic review showed that fairly good results of PFA survivorship and functional outcomes were reported at short- and midterm follow-up in the setting of isolated patellofemoral osteoarthritis. Heterogeneity existed mainly in prosthesis design and year the cohort started.

CLINICAL RELEVANCE

These results provide a clear overview of the current status of PFA in the setting of isolated patellofemoral osteoarthritis.

LEVEL OF EVIDENCE

IV.

Evidence for robots

Robots have been successfully used in commercial industry and have enabled humans to perform tasks which are repetitive, dangerous and requiring extreme force. Their role has evolved and now includes many aspects of surgery to improve safety and precision. Orthopaedic surgery is largely performed on bones which are rigid immobile structures which can easily be performed by robots with great precision. Robots have been designed for use in orthopaedic surgery including joint arthroplasty and spine surgery. Experimental studies have been published evaluating the role of robots in arthroscopy and trauma surgery. In this article, we will review the incorporation of robots in orthopaedic surgery looking into the evidence in their use.