Incidence of patellar clunk syndrome in fixed versus high-flex mobile bearing posterior-stabilized total knee arthroplasty

Modern Total Knee Arthroplasty Bearing Designs and the Role of the Posterior Cruciate Ligament

The role of the posterior cruciate ligament (PCL) in total knee arthroplasty (TKA) surgery continues to be a source of debate among the adult reconstruction community. In native knee flexion, the PCL is comprised of an anterolateral and posteromedial bundle that work together to limit posterior tibial translation and allow adequate femoral rollback for deep flexion. In the arthritic knee, the PCL can often become dysfunctional and attenuated, which led to the development of posterior stabilized (PS) TKA bearing options. PS TKAs implement a cam-post construct to functionally replace a resected PCL. While PS designs may facilitate balancing knees with significant deformity, they are associated with complications such as postfracture, increased wear, and patellar clunk/crepitus. In recent years, newer designs have been popularized with greater degrees of congruency and incorporation of medial and lateral pivoting to better recreate native knee kinematics. The American Joint Registry has confirmed the recent predilection for ultra-congruent and cruciate-retaining TKA inserts over PS TKAs during the last decade. Studies have failed to identify an overall clinical superiority between the cruciate substituting and sacrificing designs. The literature has also failed to identify clinical consequences from PCL resection with modern, more conforming TKA designs. In this article, we review modern PCL sacrificing designs and discuss the impact of each on the kinematics after TKA. We also will delineate the role of the PCL in modern TKA in the hopes to better understand the recent surge in sacrificing but not substituting knee implants.

Knee Arthroscopy After Prior Total Knee ArthroplastyType of Study: Narrative Review

Total knee arthroplasty (TKA) results in substantial improvement for most patients with end-stage arthritis of the knee; however, approximately 20% of patients have an unsatisfactory result. Although many problems contributing to an unsatisfactory result after TKA are best addressed by revision TKA, some problems may be effectively addressed with arthroscopic treatment. The categories of pathology that can be addressed arthroscopically include peripatellar soft-tissue impingement (patellar clunk syndrome and patellar synovial hyperplasia), arthrofibrosis, and popliteus tendon dysfunction. Recognizing these disease entities and the role of arthroscopic surgery in the treatment of these lesions may be helpful in achieving a good outcome in certain patients who are unsatisfied with their knee arthroplasty.

Mobile-Bearing has no Benefit Over Fixed-Bearing Total Knee Arthroplasty in Joint Awareness and Crepitus: A Randomized Controlled Trial

BACKGROUND

Given higher component conformity, rotational availability of polyethylene insert, and more physiologic patellofemoral tracking, mobile-bearing (MB) total knee arthroplasty (TKA) is supposed to offer advantages in joint perception and crepitus. The purpose of this study was to investigate whether MB TKA offers superior outcomes over fixed-bearing (FB) TKA in terms of joint awareness and crepitus.

METHODS

This prospective, randomized, controlled trial included 49 FB and 49 MB TKAs that shared the same posterior-stabilized femoral component. Primary outcomes included joint awareness assessed with the Forgotten Joint Score and crepitus graded according to severity and sound at 3 years postoperatively. Secondary outcomes were the range of motion, the Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis Index, component position, and joint line level on radiographs.

RESULTS

The Forgotten Joint Score showed no significant difference between the FB (67 points; range, 0-100) and MB groups (63 points; range, 13-100) (P = .440). For crepitus, no significant differences were found in the overall incidence rate (FB group, 18%; MB group, 12%; P = .386) and grade (grade 1, 6 versus 5; grade 2, 2 versus 1; grade 3, 1 versus 0, respectively). There were no significant differences in range of motion, Knee Society Score, and Western Ontario and McMaster Universities Osteoarthritis Index, as well as radiographic outcomes between the two groups (all, P > .05).

CONCLUSION

MB TKA offers no benefits in terms of joint awareness and crepitus compared with FB TKA at mean 3 years postoperatively. The theoretical advantages of MB TKA have yet to be demonstrated in practice, leaving the selection of bearing type to the surgeon's judgment.

LEVEL OF EVIDENCE

Level II.

Pseudomeniscus after knee arthroplasty: A case series for arthroscopic management of this problem and systematic review of literature

Introduction

Most patients undergoing total knee arthroplasty (TKA) experience favorable outcomes. Some patients, however, experience prolonged post-operative knee pain and tenderness at the joint line. This has been attributed in some cases to soft tissue impingement due to pseudomeniscus. The purpose of this study is to evaluate patient outcomes for arthroscopic excision of pseudomeniscus for persistent knee pain after TKA and to perform a review of literature for pseudomeniscus after knee arthroplasty.

Methods

A retrospective analysis of patients undergoing arthroscopy to remove soft tissue causing persistent knee pain after previous TKA was performed. Outcome scores were asked at three time points: prior to knee arthroplasty, prior to arthroscopy, and post-arthroscopy at final follow-up. Subjective satisfaction with surgery and willingness to repeat procedures were also recorded. A two-tailed distribution paired t-test was used to determine statistical significance (p < 0.05). We also performed a review of the literature for pseudomeniscus complications for comparison.

Results

Nine out of eleven patients were considered eligible to be assessed for post-operative satisfaction. Seven out of nine patients reported complete satisfaction and eight participants stated they would undergo the procedures again if they have to. Among 9 included patients, five patients have successfully completed the clinical score evaluation survey. The mean age of the patients with clinical score evaluation at the time of TKA was 61 years (range, 53-72) and the time between TKA and undergoing arthroscopy was 8 months (range, 5-13). The average follow-up period for patient-determined assessment after the arthroscopic procedure was 71 months (range, 16-115). All 5 patients reported improved Oxford Knee Scores (p=0.017), Western Ontario and McMaster Universities Osteoarthritis Index (p=0.023), and pain scores (p=0.018) comparing pre-arthroscopy to post-arthroscopy at follow-up.

Conclusion

Arthroscopic removal of pseudomeniscus after TKA provides promising results in patients who experience persistent knee joint line pain and tenderness. Considering our results and review of literature, we recommend including pseudomeniscus in the differential for post arthroplasty knee pain.

Study design

Case series with a review of literature.

Factors Affecting the Risk of Aseptic Patellar Complications in Primary TKA Performed with Cemented All-Polyethylene Patellar Resurfacing

BACKGROUND

Patellar complications are a consequential cause of failure of primary total knee arthroplasty (TKA). The purpose of this study was to evaluate the association of demographic and patient factors with the long-term risk of patellar complications as a function of time in a very large cohort of primary TKAs performed with patellar resurfacing.

METHODS

We identified 27,192 primary TKAs utilizing cemented all-polyethylene patellar components that were performed at a single institution from 1977 through 2015. We evaluated the risk of any aseptic patellar complication and any aseptic patellar reoperation or revision, subanalyzed risks of reoperation or revision for loosening, maltracking/instability, and wear, and evaluated the risk of clinical diagnosis of patellar fracture and clunk/crepitus. The mean age at TKA was 68 years (range, 18 to 99 years); 57% of the patients were female. The mean body mass index (BMI) was 32 kg/m2. The primary diagnosis was osteoarthritis in 83%, and 70% of the TKAs were posterior-stabilized. Median follow-up was 7 years (range, 2 to 40 years). Risk factors for each outcome were evaluated with Cox regression models.

RESULTS

Nine hundred and seventy-seven knees with all-polyethylene patellae developed patellar complications. Survivorship free from any aseptic patellar complication was 93.3% at 20 years. Twenty-year survivorship free from any aseptic patellar reoperation was 97.3% and free from any aseptic patellar revision was 97.4%. Fifteen-year survivorship for the same end points for procedures performed from 2000 to 2015 was 95.7%, 99.2% and 99.3% respectively, representing substantial improvements compared with implants placed before 2000. Univariate analysis demonstrated that male sex (hazard ratio [HR], 1.4), an age of <65 years (HR, 1.3), and a BMI of ≥30 kg/m2 (HR, 1.2) were associated with increased risk of patellar complications (all p ≤0.01). Posterior-stabilized designs were associated with fewer patellar reoperations and revisions overall (HR, 0.4 and 0.4; p < 0.001) but higher risk of patellar clunk/crepitus (HR, 14.1; p < 0.001).

CONCLUSIONS

The 20-year survivorship free from any aseptic patellar complication in this series of cemented all-polyethylene patellae was 93%. Important risk factors for any aseptic patellar complication were male sex, an age of <65 years, a BMI of ≥30 kg/m2, and a patella implanted before 2000.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Risk Factors for Patellar Clunk or Crepitation after Primary Total Knee Arthroplasty: A Systematic Review and Meta-analysis

Patellar clunk and crepitation (PCC) have been reported as a consequence of primary total knee arthroplasty (TKA). The incidence and contributing factors have not been fully defined. We performed this systematic review to evaluate factors associated with PCC following primary TKA. We identified studies on PCC following TKA from an electronic search of articles in Medline, Embase and the Cochrane databases (dated up to May 2018). Eighteen studies altogether, including 600 cases of PCC within 8,131 TKAs, were included in the meta-analysis. Several factors including demographic, intraoperative, clinical variables, and radiographic measurements were pooled for meta-analysis. Among intraoperative and clinical variables, patients involved with patellar retention (odds ratio [OR] = 9.420; confidence interval [CI]: 5.770-13.070), lateral reticular release (OR = 2.818; CI: 1.114-7.125), and previous surgery (OR = 2.724; CI: 1.549-4.790) were more likely to having PCCs. Among radiographic measurements, increased anterior tibial offset (weighted mean difference [WMD] = 0.387; CI: 0.139-0.634), increased joint line changes (WMD = 1.325; CI: 0.595-2.055), and increased knee flexion angle (WMD = 3.592; CI: 1.811-5.374) were considered risk factors associated with PCC. Demographic factors (age, gender, body mass index [BMI], and diagnosis) and other reported radiographic measurements were not associated with PCCs. This study identified intraoperative variables (patellar retention and lateral reticular release), clinical variables (previous surgery), and radiographic measurements (increased anterior tibial offset, increased joint line changes, and increased postoperative knee flexion angle) that contribute to an increased risk for PCC. Modifiable factors (patellar retention and lateral reticular release) should be considered and addressed to limit the risk for PCC following TKA. Patients with conditions that may not be modifiable may benefit from counseling about their increased risks for PCC to limit potential dissatisfaction with their procedure.

Patellar Clunk Syndrome Following Posterior Stabilized Total Knee Replacement: Report of Two Cases

Patellar clunk syndrome (PCS) occasionally occurs after posterior stabilized total knee replacement (PS-TKR), and is characterized by a painful palpable audible clunk of the patella when the knee moves from flexion to extension. It has been classically attributed to the formation of fibrous nodule at the junction of the proximal pole of the patella and the undersurface of the distal quadriceps tendon. However, various intra-articular peripatellar proliferative fibrous formations have also been reported with a wide spectrum of symptoms, ranging from crepitation to frank patellar clunk. Treatment of the syndrome remains essentially surgical, and usually consists of resection of the fibrous nodules. This paper reports two cases of PCS and aims at bringing attention to this entity in terms of pathogenesis, clinical diagnosis, and treatment, through a review of the literature.

Comparison Between the Attune and PFC Sigma in Total Knee Arthroplasty: No Difference in Patellar Clunk and Crepitus or Anterior Knee Pain

Patellar crepitus and clunk (PCC) is a known complication in total knee arthroplasty (TKA) and the cause of dissatisfaction. Patellofemoral articulations have reportedly been optimized in newer TKAs. This study compared the incidence of PCC between a historical and modern TKA design. A single-surgeon retrospective review of primary PFC Sigma (DePuy Synthes, Warsaw, Indiana) or Attune TKA (DePuy Synthes) was performed. A total of 114 PFC Sigma and 103 Attune implants were analyzed at a mean 3.2 years follow-up for overall PCC, painful PCC, anterior knee pain (regardless of crepitus), and PCC necessitating revision. Similar rates of overall PCC (14.6% vs 20.2%, P=.803), painful PCC (8.7% vs 6.1%, P=.605), and anterior knee pain (15.5% vs 9.7%, P=.219) were observed in the Attune and PFC Sigma groups, respectively. No clinically significant differences in range of motion, pain, or Knee Society Scores were found between groups. Subgroup analyses of mobile vs fixed bearing PFC Sigma implants demonstrated higher rates of overall PCC (32.4% vs 15.0%, P=.043), painful PCC (20.6% vs 5.0%, P=.016), anterior knee pain (17.6% vs 1.3%, P=.003), and crepitus requiring revision surgery (17.6% vs 1.3%, P=.003) for mobile bearing PFC Sigma implants. No difference was found in the rates of anterior knee pain or PCC between the PFC Sigma and Attune implants. Subgroup analysis suggests that a mobile bearing PFC Sigma implant results in higher PCC. The authors believe the true incidence of anterior knee pain and PCC is underreported in the literature because many outcome measures do not capture these complications. [Orthopedics. 2020;43(6):e508-e514.].

Systematic review of the etiology behind patellar clunk syndrome

BACKGROUND

Total knee arthroplasty is one of the most successful operations performed worldwide today. Patellar clunk syndrome (PCS) is a postoperative complication that arises due to the development of a fibrous nodule along the undersurface of the quadriceps tendon. The current literature on PCS has not yet come to a consensus regarding its etiology. To date, this is the first study that analyzes the existing literature on PCS in order to generate a conclusion regarding its etiology. It is hypothesized that prosthesis design is the main component behind the development of PCS.

AIM

To determine the etiology of PCS and its association with pre and post-operative characteristics of the prosthesis and native knee.

METHODS

We conducted a systematic review according to the PRISMA guidelines by searching through PubMed, Cochrane, and Google Scholar from May-July 2018 for cases of PCS using search MeSH terms “patella OR patellar” AND “clunk” OR “catch” OR “crepitus”. The search included case series and clinical trials and excluded review articles, yielding 30 articles from the original search and 3 additional articles from reference lists. We extracted data upon the outcomes in patients afflicted with PCS to determine the etiology of PCS. We performed additional bias assessments to validate our search algorithm and results.

RESULTS

Prosthesis design was the metric most frequently implicated in the incidence of PCS, though several other metrics were contributory toward its pathogenesis. Later prosthetic designs incorporate a reduced intercondylar box ratio and box width to reduce contact between the proximal patellar pole and the intercondylar box, thereby reducing incidence of PCS.

CONCLUSION

The etiology of PCS is multifactorial, owing to the growing metrics that have associations with its incidence. This conclusion is validated by the significance of prosthesis design as the most likely parameter involved in developing PCS since different prosthesis designs are often the result of different parameters. Future studies should be directed at isolating individual prosthetic parameters of prosthesis designs in order to determine what permutation of parameters is most closely associated with the development of PCS.

Patellar complications following total knee arthroplasty: a review of the current literature

Total knee arthroplasty is a common operation for treating patients with end-stage knee osteoarthritis and generally has a good outcome. There are several complications that may necessitate revision of the implants. Patella-related complications are difficult to treat, and their consequences impact the longevity of the implanted joint and functional outcomes. In this review, we explore the current literature on patellar complications in total knee arthroplasty and identify risk factors as well as strategies that can help in preventing these complications. We present pertinent findings relating to patellar complications. They can be classified into bony or soft tissue complications and include bone loss, aseptic loosening, periprosthetic fractures, patella fracture, patellar clunk syndrome, patellofemoral instability, extensor mechanism complications, maltracking, patella baja and malrotation. We conclude that patellar complications in total knee arthroplasty are common and have significant implications for the functional outcome of total knee arthroplasty. A high index of suspicion should be maintained in order to avoid them. Implant malpositioning and other forms of intraoperative technical error are the main cause of these complications, and therefore, primary prevention is crucial. When dealing with these established problems, a clear plan of action should be formulated in advance to allow appropriate management as well as anticipation of adverse outcomes.

Resurfacing versus not-resurfacing the patella in one-stage bilateral total knee arthroplasty: a prospective randomized clinical trial

Purpose

Resurfacing the patella in one-stage bilateral total knee arthroplasty (TKA) remains debatable. This study aimed to assess the mid-term outcomes of patients after one-stage bilateral TKA performed with and without patellar resurfacing, respectively, with at least five years of follow-up.

Methods

Sixty-six patients (132 knees) scheduled for first-ever one-stage bilateral TKA due to osteoarthritis received patellar resurfacing and retention, respectively, on one knee and the other, randomly selected. All patients received Scorpio NRG knee prostheses and were evaluated by radiology (anteroposterior, lateral, and axial views) pre-operatively and yearly post-operatively, for at least five years. Knee Society Score and Feller Score values were measured. Anterior knee pain, patellar clunk, and patient satisfaction were assessed.

Results

One patient died within five years of operation and four were lost to follow-up. One patient developed severe dementia and could not be constructively questioned. Therefore, 60 patients (120 knees) were finally analyzed. There were significantly improved Knee Society and Feller scores (P < 0.001) in the resurfacing group compared with the non-resurfacing group post-operatively. Anterior knee pain and patellar clunk rates were lower on the resurfaced side compared with the non-resurfaced side (P < 0.001). Meanwhile, 47% and only 7% patients preferred the resurfaced and non-resurfaced sides, respectively, at final follow-up. No revision was performed for patellofemoral complications, and no significant differences were found between the two groups in radiographic outcomes.

Conclusions

Using the Scorpio NRG knee prosthesis, patellar resurfacing is superior to non-resurfacing in patients with osteoarthritis observed for ≥ five years.

Registration trials number

NCT03600922

Key Points

• Findings Patellar resurfacing is superior to non-resurfacing in osteoarthritis (OA) patients undergoing total knee arthroplasty (TKA) with the Scorpio NRG knee prosthesis.

• Implications Patellar resurfacing should be performed in OA patients during TKA.

• Caution Several prosthesis types should be assessed in the same study setting, and multicenter studies are required before generalizability of the present findings.

Electronic supplementary material

The online version of this article (10.1007/s00264-019-04361-7) contains supplementary material, which is available to authorized users.

Arthroscopic treatment of total knee arthroplasty complications

The most frequent indications for arthroscopy in patients with total knee arthroplasty (TKA) are soft-tissue impingement, arthrofibrosis (knee stiffness), periprosthetic infection and removal of free bodies or cement fragments.

When performing a knee arthroscopy in a patient with a symptomatic TKA, look for possible free/retained bone or cement fragments, which can be anywhere in the joint.

Patellar tracking should be evaluated and soft-tissue impingement under the patella or between the femoral and tibial prosthetic components should be ruled out.

Current data suggest that knee arthroscopy is an effective procedure for the treatment of some patients with symptomatic TKA.

The approximate rates of therapeutic success vary according to the problem in question: 85% in soft-tissue impingement; 90% in arthrofibrosis; and 55% in periprosthetic infections.

More clinical studies are needed to determine which patients with symptomatic TKA can be the best candidates for knee arthroscopy.

Cite this article: EFORT Open Rev 2019;4:33-43. DOI: 10.1302/2058-5241.4.180035.

Survivorship of Metaphyseal Sleeves in Revision Total Knee Arthroplasty

BACKGROUND

Metaphyseal fixation has promising early results in providing component stability and fixation in revision total knee arthroplasty (TKA). However, there are limited studies on midterm results of metaphyseal sleeves. We analyzed complications, rerevisions, and survivorship free of revision for aseptic loosening of metaphyseal sleeves in revision TKA.

METHODS

Two hundred eighty patients with 393 metaphyseal sleeves (144 femoral, 249 tibial) implanted during revision TKA from 2006-2014 were reviewed. Sleeves were most commonly cemented (55% femoral, 72% tibial). Mean follow-up was 3 years, mean age was 66 years, and mean body mass index was 34 kg/m². Indications for revision TKA included 2-stage reimplantation for deep infection (37%), aseptic loosening of the tibia (14%), femur (12%), or both components (9%), and instability (14%).

RESULTS

There was a 12% rate of perioperative complications, most commonly intraoperative fracture (6.5%). Eight sleeves (2.5%) required removal: 6 (2%) during component resection for deep infection (all were well-fixed at removal) as well as 1 (0.8%) femoral sleeve and 1 (0.8%) tibial sleeve for aseptic loosening. Five-year survivorship free of revision for aseptic loosening was 96% and 99.5% for femoral and tibial sleeves, respectively. Level of constraint, bone loss, sleeve and/or stem fixation, and revision indication did not significantly affect outcomes.

CONCLUSION

Metaphyseal sleeve fixation to enhance component stability during revision TKA has a 5-year survivorship free of revision for aseptic loosening of 96% and 99.5% in femoral and tibial sleeves, respectively. Both cemented and cementless sleeve fixation provides reliable durability at intermediate follow-up.

Femoral Implant Design Modification Decreases the Incidence of Patellar Crepitus in Total Knee Arthroplasty

BACKGROUND

Patellar crepitus is a complication most commonly seen in patients implanted with a posterior-stabilized total knee arthroplasty (TKA). Recently, design changes in the patellofemoral geometry and the intercondylar box ratio have been optimized in newer TKA designs. A comparative study was performed to analyze the incidence of patellar crepitus between a historical vs modern TKA design.

METHODS

A retrospective review of all patients at our institution that underwent a primary TKA with either a PFC Sigma or Attune posterior-stabilized TKA (DePuy, Inc, Warsaw, IN), with a minimum of 1-year follow-up duration was performed. A total of 1165 participants implanted with the PFC Sigma and 728 with the Attune design were analyzed. Patellar crepitus incidence, functional scores, and range of motion were recorded at each follow-up appointment. Statistical analyses were performed between the 2 groups to determine if there were differences in clinical outcomes.

RESULTS

The incidence of crepitus in participants implanted with the Attune was 0.55% vs 6.26% in the PFC Sigma cohort (P < .001) at 1 year vs. 0.83% vs 9.4%, respectively at 2 years post operatively (P < .001). There were small differences in extension, flexion, and Knee Society Scores between the 2 groups that were not clinically meaningful.

CONCLUSION

The Attune posterior-stabilized TKA demonstrated substantially less patellofemoral crepitus incidence than the historical control. We hypothesize that these findings are related to femoral component changes including a thinner and narrower anterior flange and a reduced femoral intercondylar box ratio.

Mobile bearing and fixed bearing total knee arthroplasty

The mobile bearing (MB) concept in total knee arthroplasty (TKA) was developed as an alternative to fixed bearing (FB) implants in order to reduce wear and improve range of motion (ROM), especially focused on younger patients. Unfortunately, its theoretical advantages are still controversial. In this paper we exhibit a review of the more recent literature available comparing FB and MB designs in biomechanical and clinical aspects, including observational studies, clinical trials, national and international registries analyses, randomized controlled trials, meta-analyses and Cochrane reviews. Except for some minor aspects, none of the studies published so far has reported a significant improvement related to MBs regarding patient satisfaction, clinical, functional and radiological outcome or medium and long-term survivorship. Thus the presumed superiority of MBs over FBs appears largely inconsistent. The routine use of MB is not currently supported by adequate evidences; implant choice should be therefore made on the basis of other factors, including cost and surgeon experience.