Comparison of fixed and mobile-bearing total knee arthroplasty in terms of patellofemoral pain and function: a prospective, randomised, controlled trial

Patient Selection in Randomized Controlled Trials of Total Knee Arthroplasty: A Systematic Review Assessing Inclusion Criteria

BACKGROUND

Patients undergo total knee arthroplasty (TKA) at widely disparate stages of osteoarthritis, raising the possibility of high heterogeneity among patients enrolled in TKA research studies. Obscuration of treatment effectiveness and other problems that may stem from cohort heterogeneity can be controlled in clinical studies by rigorously defining target patients. The purpose of this review was to determine the extent to which randomized controlled trials (RCTs) on TKA use osteoarthritis severity, as defined by radiographic grade or patient-reported outcome measures (PROMs), in their inclusion criteria, and to investigate potential impact on outcome.

METHODS

A search of PubMed, Embase, Scopus, Web of Science, and Cochrane databases used a combination of terms involving TKA, PROMs, and radiographic scoring. A total of 1,227 studies were independently reviewed by 2 screeners for the above terms. RCTs with ≥100 patients (236) and with <100 patients (325) undergoing TKA were analyzed with regard to the specific inclusion criteria and recruitment process.

RESULTS

Among the identified RCTs with ≥100 patients, 18 (<8%, with a total of 2,952 randomized patients) used specific radiographic scoring or PROM thresholds in their inclusion criteria. Eleven of the 18 studies used specific radiographic scoring, such as the Kellgren-Lawrence or Ahlbäck classifications. Three studies used preoperative PROM thresholds: Knee Society Knee Score of <60, Knee Society Function Score of <60, Oxford Knee Score of <20, and Hospital for Special Surgery Score of <60. Among studies with <100 patients, 48 (<15%) used specific inclusion criteria.

CONCLUSIONS

The vast majority of RCTs (>85%) did not enroll patients based on disease severity, as measured by PROM score thresholds or radiographic classifications, in their inclusion criteria. The lack of consistent inclusion criteria likely results in heterogeneous cohorts, potentially undermining the validity of RCTs on TKA.

LEVEL OF EVIDENCE

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

Meta-analysis of factors influencing anterior knee pain after total knee arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is a mature procedure recommended for correcting knee osteoarthritis deformity, relieving pain, and restoring normal biomechanics. Although TKA is a successful and cost-effective procedure, patient dissatisfaction is as high as 50%. Knee pain after TKA is a significant cause of patient dissatisfaction; the most common location for residual pain is the anterior region. Between 4% and 40% of patients have anterior knee pain (AKP).

AIM

To investigate the effect of various TKA procedures on postoperative AKP.

METHODS

We searched PubMed, EMBASE, and Cochrane from January 2000 to September 2022. Randomized controlled trials with one intervention in the experimental group and no corresponding intervention (or other interventions) in the control group were collected. Two researchers independently read the title and abstract of the studies, preliminarily screened the articles, and read the full text in detail according to the selection criteria. Conflicts were resolved by consultation with a third researcher. And relevant data from the included studies were extracted and analyzed using Review Manager 5.4 software.

RESULTS

There were 25 randomized controlled trials; 13 were comparative studies with or without patellar resurfacing. The meta-analysis showed no significant difference between the experimental and control groups (P = 0.61). Six studies were comparative studies of circumpatellar denervation vs non-denervation, divided into three subgroups for meta-analysis. The two-subgroup meta-analysis showed no significant difference between the experimental and the control groups (P = 0.31, P = 0.50). One subgroup meta-analysis showed a significant difference between the experimental and control groups (P = 0.001). Two studies compared fixed-bearing TKA and mobile-bearing TKA; the results meta-analysis showed no significant difference between the experimental and control groups (P = 0.630). Two studies compared lateral retinacular release vs non-release; the meta-analysis showed a significant difference between the experimental and control groups (P = 0.002); two other studies compared other factors.

CONCLUSION

Patellar resurfacing, mobile-bearing TKA, and fixed-bearing TKA do not reduce the incidence of AKP. Lateral retinacular release can reduce AKP; however, whether circumpatellar denervation can reduce AKP is controversial.

No significant clinical and radiological differences between fixed versus mobile bearing total knee replacement using the same semi-constrained implant type: a randomized controlled trial with mean 10 years follow-up

PURPOSE

The aim of this study was to compare the long-term clinical and radiological results between fixed (FB) and mobile bearing (MB) implants with identical design from the same manufacturer.

METHODS

From March 2007 to May 2009, we recruited 160 patients in a prospective, single centered, randomized controlled trial. The authors compared 81 FB total knee arthroplasty (TKA) versus 79 MB with medial compartment osteoarthritis. The same posterior stabilized HLS Noetos knee prosthesis (CORIN) was used in all patients. The two groups only differed by the tibial insert (fixed or mobile). The authors compared the postoperative Knee Society Score (KSS), the passive clinical and active radiological knee flexion, the implant survivorship, the complications, and the presence of radiolucent lines.

RESULTS

At mean 10.5 years' follow-up (range 8-12.1 years) no significant differences were found in clinical scores (KSS (p = 0.54), pain score (p = 0.77), stair climbing (p = 0.44), passive maximum flexion (p = 0.5)) or for radiological analyses (maximum active radiological flexion (p = 0.06), presence of progressive radiolucent lines (5 (MB group) versus 6 (FB group); p = 0.75)) between groups. No significant difference was found in overall implant survivorship (82% (MB group) versus 78% (FB group) p = 0.58) or complication rate (p = 0.32) at the last follow-up.

CONCLUSION

No significant clinical and radiological differences were found between fixed and mobile bearing TKA using the same semi-constrained implant type with comparable overall survivorship. The choice between a fixed or mobile bearing implant should be based on surgeon preference and experience with the selected implant.

LEVEL OF EVIDENCE

Prospective randomized controlled trial, Level II.

No difference between mobile and fixed bearing in primary total knee arthroplasty: a meta-analysis

PURPOSE

Both mobile (MB) and fixed (FB) bearing implants are routinely used for total knee arthroplasty (TKA). This meta-analysis compared MB versus FB for TKA in terms of implant positioning, joint function, patient reported outcome measures (PROMs), and complications. It was hypothesised that MB performs better than FB implants in primary TKA.

METHODS

This meta-analysis was conducted according to the 2020 PRISMA statement. In February 2022, the following databases were accessed: Pubmed, Web of Science, Google Scholar, Embase. All the randomized clinical trials (RCTs) comparing mobile versus fixed bearing for primary TKA were considered.

RESULTS

Data from 74 RCTs (11,116 procedures) were retrieved. The mean follow-up was 58.8 (7.5 to 315.6) months. The MB group demonstrated greater range of motion (ROM) (P = 0.02), Knee Society Score (KSS) score (P < 0.0001), and rate of deep infections (P = 0.02). No difference was found in implant positioning: tibial slope, delta angle, alpha femoral component angle, gamma femoral component angle, beta tibial component angle, tibiofemoral alignment angle, posterior condylar offset, radiolucent lines. No difference was found in duration of the surgical procedure. No difference was found in the following PROMs: Oxford Knee Score (OKS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), visual analogue scale (VAS), function and pain subscales of the KSS score. No difference was found in the rate of anterior knee pain, revision, aseptic loosening, fractures, and deep vein thrombosis.

CONCLUSION

There is no evidence in support that MB implants promote greater outcomes compared to FB implants in primary TKA.

LEVEL OF EVIDENCE

Level I.

Superior Mid- to Long-Term Clinical Outcomes of Mobile-Bearing Total Knee Arthroplasty Compared to Fixed-Bearing: A Meta-Analysis Based on a Minimum of 5 Years of Study

As more patients undergo total knee arthroplasty (TKA) each year, and the average age of patients gets younger, the patients are generally more active requiring a greater physiological demand and increasing range of motion on the prosthesis than the previous patients. However, there is no consensus on the optimal TKA tibial bearing design. We performed this systematic review to compare the clinical differences between mobile and fixed bearing constructs used in contemporary TKA. We searched PubMed, EMBASE, and Cochrane Library databases, identifying 515 total publications, including 17 randomized controlled trials (RCTs). A meta-analysis was performed, while the quality and bias of the evidence were rated according to the Grading of Recommendations Assessment Development and Evaluation (GRADE) guidelines and the Cochrane Database questionnaire. The meta-analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Seventeen studies were included, with a total of 1505 knees receiving a mobile bearing TKA and 1550 knees receiving a fixed bearing TKA. The meta-analysis compared clinical outcomes between mobile bearing (MB)-TKA and fixed bearing (FB)-TKA using postoperative Knee Society Score, postoperative ROM, and survivorship and showed that there was a distinct difference in Knee Society Score between the mobile-bearing and fixed-bearing groups (overall standardized mean difference = 1.38; 95% confidence interval (CI): 0.50-2.25; p = 0.002; I² = 60%). Patients treated with mobile-bearing prostheses were more likely to report good or excellent range of motion results (overall standardized mean difference = 2.06; 95% CI: 0.65-3.47; p = 0.004). No difference in implant survivorship or reoperation rate were identified. The fixed-bearing and mobile-bearing TKA designs are both capable of producing excellent long-term results with excellent clinical outcomes if properly implanted; however, the mobile-bearing TKA have superiority in mid- to long-term clinical results. Trial registration number for PROSPERO was CRD42019126402.

Fixed-bearing vs mobile-bearing prostheses for total knee arthroplasty after approximately 10 years of follow-up: a meta-analysis

Background

The benefits and risks of fixed-bearing and mobile-bearing designs for total knee arthroplasty (TKA) were compared, and long-term functional, clinical and radiological outcomes were analysed.

Methods

A comprehensive search in the PubMed, EMBASE, Web of Science and Cochrane Central databases was conducted to identify randomized controlled trials (RCTs) comparing fixed-bearing and mobile-bearing designs with no less than 9 years of follow-up. Primary outcome measures were Knee Society Scores (KSSs), range of motion (ROM) in knee joint values, complication rates and revision rates. The final search was performed on 23 April 2021.

Results

Six RCTs were included. A total of 451 patients with 612 knees met the inclusion criteria. The mobile-bearing design, in contrast to the fixed-bearing design, can clearly increase the KSFSs, especially with posterior cruciate retention. There was no significant difference in the KSKSs, ROM values, revision rates or complication rates between the two bearing design groups.

Conclusion

After approximately 10 years of follow-up, the mobile-bearing design has advantages in KSFSs over the fixed-bearing design. The mobile-bearing design may also have advantages in the revision rates over the fixed-bearing design when the posterior cruciate ligament is substituted. There may be no clear difference in KSKSs, ROM values or complication rates between these two designs.

Mobile-bearing versus fixed-bearing total knee arthroplasty: a meta-analysis of randomized controlled trials

Objective

The purpose of this study was to perform a meta-analysis comparing mobile-bearing with fixed-bearing total knee arthroplasty (TKA) in terms of all-cause revision rates, aspetic loosening, knee functional scores, range of motion and radiographic lucent lines and osteolysis.

Methods

PubMed, Cochrane Library, Google Scholar and Web of Science were searched up to January 2020. Randomized controlled trials that compared primary mobile-bearing with fixed-bearing TKA, reporting at least one of the outcomes of interest, at a minimum follow-up of 12 months were included. All outcomes of interest were pooled at short-term (< 5 years), mid-term (5 to 9 years) and long-term (> = 10 years) follow-up intervals.

Results

A total of 70 eligible articles were included in the qualitative and statistical analyses. There was no difference between mobile-bearing or fixed-bearing TKA at short-term, mid-term and long-term follow-ups in all outcome measures including all-cause revision rate, aseptic loosening, oxford knee score, knee society score, Hospital for Special Surgery score, maximum knee flexion, radiographic lucent lines and radiographic osteolysis.

Conclusion

The current level of evidence demonstrated that both mobile-bearing and fixed-bearing designs achieved excellent outcomes, yet it does not prove the theoretical advantages of the mobile-bearing insert over its fixed-bearing counterpart. The use of either design could therefore be supported based on the outcomes assessed in this study.

Level of Evidence: Level II, Therapeutic

Supplementary information

The online version contains supplementary material available at (10.1007/s00590-021-02999-x).

Investigation of association between the preoperative intra-articular anesthetic test and persistent pain after total knee arthroplasty

BACKGROUND

A better understanding of the etiology of persistent pain after total knee arthroplasty (TKA) is required to prevent unfavorable outcomes. The purpose of this study was to investigate the association of persistent pain after TKA, patient characteristics, and the remaining pain ratio per the preoperative intra-articular anesthetic test.

METHODS

This study included 89 patients who underwent TKA and underwent an intra-articular anesthetic test preoperatively. The remaining pain ratio out of 100 percent 30 min after intra-articular anesthetic injection and demographic data were also evaluated preoperatively. Numerical rating scale (NRS) scores for pain during movement (Q1), at rest (Q2), at first movement in the morning (Q3), and during climbing up and down stairs (Q4) were evaluated 1 year after TKA. Multiple linear regression analysis was performed to assess the impact of independent variables on the NRS score for questionnaire No.4. and the remaining pain ratio per the intra-articular anesthetic.

RESULTS

The mean remaining pain ratio per the preoperative intra-articular anesthetic test was 29.3%. The NRS score for Q4 was significantly higher than those for any of the other NRS questionnaires administered 1 year after TKA (Q1-Q4, Q2-Q4, P < 0.001; Q3-Q4, P < 0.05). The analysis found the weak correlation between the pain ratio of anesthetic test and the NRS score for Q4 after TKA (R = 0.28, P = 0.018). BMI and preoperative FTA were the major predictors of remaining pain ratio per the intra-articular anesthetic test (R = 0.40, P = 0.002).

CONCLUSION

This study revealed that the remaining pain ratio per the preoperative intra-articular anesthetic test was weakly correlated with persistent pain during climbing up and down stairs 1 year after TKA. In addition, BMI and preoperative FTA were associated with the remaining pain ratio per the preoperative intra-articular anesthetic test.

No difference in patellar position between mobile-bearing and fixed-bearing total knee arthroplasty for medial osteoarthritis: a prospective randomized study

PURPOSE

Total knee arthroplasty (TKA) is the treatment of choice for severe osteoarthritis of the knee. Many studies have been performed comparing mobile- and fixed-bearing designs; however, there are insufficient data regarding the patellar position in either system. This study aimed to compare the resultant patellar position with a mobile- versus a fixed-bearing TKA and the influence of both designs on clinical outcomes.

MATERIALS AND METHODS

In this prospective randomized study, between 2007 and 2009, 160 TKA patients were assessed; 79 received a mobile-bearing and 81 received a fixed-bearing implant, for medial compartment osteoarthritis. A posteriorly stabilized, HLS Noetos knee prosthesis (Tornier, Saint-Ismier, France) was used in all cases. The only difference between the groups was whether the tibial component incorporated a fixed or mobile bearing. The patella was resurfaced in all cases. The International Knee Society Score (KSS) and the patellar tilt and translation were compared post-operatively. Patellar translation and patellar tilt analyses were subdivided into two subgroups (< 5 mm vs > 5 mm and < 5° vs > 5°).

RESULTS

The KSS was not statistically different between the groups at a mean follow-up of 7.4 years (range 5-11 years). Patellar translation and patellar tilt were not statistically different between the groups. When considering the patellar translation subgroup analysis, a significantly increased risk of patellar translation, greater than 5 mm, was found in the mobile-bearing group compared to fixed-bearing group (OR = 2.3; p = 0.048) without generating any meaningful difference in clinical outcomes.

CONCLUSION

The theoretical advantages of mobile-bearing implants compared to fixed-bearing implants were not demonstrated in this randomized study, at mid-term follow-up. In daily practice, the choice between mobile-bearing and fixed-bearing designs should be based on the experience and clinical judgment of the surgeon.

LEVEL OF EVIDENCE

Prospective randomized study, level I.

Association Between Femoral Component Sagittal Positioning and Anterior Knee Pain in Total Knee Arthroplasty: A 10-Year Case-Control Follow-up Study of a Cruciate-Retaining Single-Radius Design

BACKGROUND

Anterior knee pain is the most common complication of total knee arthroplasty (TKA). The purpose of this study was to assess whether sagittal femoral component position is an independent predictor of anterior knee pain after cruciate-retaining single-radius TKA without routine patellar resurfacing.

METHODS

A prospective cohort study of 297 cruciate-retaining single-radius TKAs performed in 2006 and 2007 without routine patellar resurfacing identified 73 patients (25%) with anterior knee pain and 89 (30%) with no pain (controls) at 10 years. Patients were assessed preoperatively and at 1, 5, and 10 years postoperatively using patient-reported outcome measures (PROMs), including the Short Form-12 (SF-12), Oxford Knee Score (OKS), and satisfaction and expectation questionnaires. Variables that were assessed as predictors of anterior knee pain included demographic data, the indication for the TKA, early complications, stiffness requiring manipulation under anesthesia, and radiographic criteria (implant alignment, Insall-Salvati ratio, posterior condylar offset ratio, and anterior femoral offset ratio).

RESULTS

The 73 patients with anterior knee pain (mean age, 67.0 years [range, 38 to 82 years]; 48 [66%] female) had a mean visual analog scale (VAS) score of 34.3 (range, 5 to 100) compared with 0 for the 89 patients with no pain (mean age, 66.5 years [range, 41 to 82 years]; 60 [67%] female). The patients with anterior knee pain had mean femoral component flexion of -0.6° (95% confidence interval [CI] = -1.5° to 0.3°), which differed significantly from the value for the patients with no pain (1.42° [95% CI = 0.9° to 2.0°]; p < 0.001). The patients with and those without anterior knee pain also differed significantly with regard to the mean anterior femoral offset ratio (17.2% [95% CI = 15.6% to 18.8%] compared with 13.3% [95% CI = 11.1% to 15.5%]; p = 0.005) and the mean medial proximal tibial angle (89.7° [95% CI = 89.2° to 90.1°] compared with 88.9° [95% CI = 88.4° to 89.3°]; p = 0.009). All PROMs were worse in the anterior knee pain group at 10 years (p < 0.05), and the OKSs were worse at 1, 5, and 10 years (p < 0.05). Multivariate analysis confirmed femoral component flexion, the medial proximal tibial angle, and an Insall-Salvati ratio of <0.8 (patella baja) as independent predictors of anterior knee pain (R = 0.263). Femoral component extension of ≥0.5° predicted anterior knee pain with 87% sensitivity.

CONCLUSIONS

In our study, 25% of patients had anterior knee pain at 10 years following a single-radius cruciate-retaining TKA without routine patellar resurfacing. Sagittal plane positioning and alignment of the femoral component were associated with long-term anterior knee pain, with femoral component extension being a major risk factor.

LEVEL OF EVIDENCE

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

A randomized prospective study comparing mobile-bearing against fixed-bearing PFC Sigma cruciate-retaining total knee arthroplasties with ten-year minimum follow-up

AIMS

This study compares the PFC total knee arthroplasty (TKA) system in a prospective randomized control trial (RCT) of the mobile-bearing rotating-platform (RP) TKA against the fixed-bearing (FB) TKA. This is the largest RCT with the longest follow-up where cruciate-retaining PFC total knee arthroplasties are compared in a non-bilateral TKA study.

PATIENTS AND METHODS

A total of 167 patients (190 knees with 23 bilateral cases), were recruited prospectively and randomly assigned, with 91 knees receiving the RP and 99 knees receiving FB. The mean age was 65.5 years (48 to 82), the mean body mass index (BMI) was 29.7 kg/m² (20 to 52) and 73 patients were female. The Knee Society Score (KSS), Knee Society Functional Score (KSFS), Oxford Knee Score (OKS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), and 12-Item Short-Form Health Survey Physical and Mental Component Scores (SF-12 PCS, SF-12 MCS) were gathered and recorded preoperatively, at five-years' follow-up, and at ten years' follow-up. Additionally, Knee Injury and Osteoarthritis Outcome Scores (KOOS) were collected at five- and ten-year follow-ups. The prevalence of radiolucent lines (RL) on radiographs and implant survival were recorded at five- and ten-year follow-ups.

RESULTS

At the ten-year follow-up, the RP group (n = 39) had a statistically significant superior score in the OKS (p = 0.001), WOMAC (p = 0.023), SF-12 PCS (p = 0.019), KOOS Activities of Daily Living (ADL) (p = 0.010), and KOOS Sport and Recreation (Sport/Rec) (p = 0.006) compared with the FB group (n = 46). The OKS, SF-12 PCS, and KOOS Sport/Rec at ten years had mean scores above the minimal clinically important difference (MCID) threshold. There was no significant difference in prevalence of radiolucency between groups at five-years' follow-up (p = 0.449), nor at ten-years' follow-up (p = 0.08). Implant survival rate at 14 years postoperative was 95.2 (95% CI 90.7 to 99.8) and 94.7 (95% CI 86.8 to 100.0) for the RP and FB TKAs, respectively.

CONCLUSION

At ten-year follow-up, the mobile-bearing knee joint arthroplasty had statistically and clinically relevant superior OKS, SF-12 PCS, and KOOS (Sport/Rec) than the fixed-bearing platform. No difference was seen in prevalence of radiolucent lines. There was a greater than 94% implant survival rate for both cohorts at 14 years. Cite this article: Bone Joint J 2018;100-B:1336-44.

Different Factors Conduct Anterior Knee Pain Following Primary Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

A systematic review and meta-analysis was performed to investigate the risks associated with anterior knee pain (AKP) following primary total knee arthroplasty (TKA).

METHODS

A computerized search was performed of the following databases: MEDLINE, Embase, and Cochrane Central (published prior to July 2017). A total of 37 studies, which included 1641 cases of AKP and 168,090 TKAs, were included in the meta-analysis.

RESULTS

A subgroup analysis revealed that compared with those without the following medical conditions, patients who had an infrapatellar fat pad excision and more than 12 months of follow-up (odds ratio [OR] 12.58, 95% confidence interval [CI] 3.245-48.781) were more likely to have AKP after TKA. Circumpatellar electrocautery (>12 months: OR 0.50, 95% CI 0.326-0.760; ≤12 months: OR 0.59, 95% CI 0.408-0.867) and patellar resurfacing (OR 0.25, 95% CI 0.131-0.485) may decrease the risk of AKP. Other factors, including the prosthesis bearing type (mobile bearing or fixed bearing) and the approach (midvastus compared with the medial parapatellar approach), were not significant risk factors for AKP.

CONCLUSION

The use of strategies such as patellar denervation and patellar resurfacing in primary TKA is recommended because they are safe and result in good clinical outcomes in preventing AKP. Caution should be taken when using an infrapatellar fat pad excision, because there is an increased risk of AKP at long-term follow-up (>12 months). Future studies should investigate these different strategies to confirm the underlying mechanisms and help prevent the occurrence of AKP after TKA. The timing of AKP onset remains unclear and requires further research.

Guiding Device for the Patellar Cut in Total Knee Arthroplasty: Design and Validation

An incorrect cut of the patella (kneecap) during total knee arthroplasty, affects the thickness in different quadrants of the patella, leading to pain and poor function. Because of the disadvantages of existing devices, many surgeons choose to perform the cut freehand. Given this mistrust of existing devices, a quick, but accurate, method is needed that guides the cut, without constraining the surgeon. A novel device is described that allows the surgeon to mark a line at the desired cutting plane parallel to the front (anterior) surface using a cautery tool, remove the device, and then align the saw guide, reamer, or freehand saw with the marked line to cut the patella. The device was tested on 36 artificial patellae, custom-molded from two shapes considered easier and harder to resect accurately, and eight paired cadaveric specimens, each in comparison to the conventional saw guide technique. The mediolateral angle, superoinferior angle, difference from intended thickness, and time were comparable or better for the new device. Addressing the remaining outliers should be possible through additional design changes. Use of this guidance device has the potential to improve patellar resection accuracy, as well as provide training to residents and a double-check and feedback tool for expert surgeons.