A comparison of lateral release rates in fixed- versus mobile-bearing total knee arthroplasty

Patellar Resurfacing in Primary Total Knee Arthroplasty: A Meta-analysis and Trial Sequential Analysis of 50 Randomized Controlled Trials

OBJECTIVE

During total knee arthroplasty, femur and tibia parts are regularly replaced, while resurfacing the patellar or not is an ongoing discussion. To compare revision rate, anterior knee pain rate, patient-reported outcome measures, complication, radiographic, and clinical outcomes after patellar resurfacing versus non-resurfacing in total knee arthroplasty.

METHODS

PubMed, Medline, EMBASE, CENTRAL, and CINAHL databases were searched on 25 April 2021 to enroll randomized controlled trials that compared patellar resurfacing versus non-resurfacing. We used the grading of recommendations assessment, development and evaluation (GRADE) framework to assess the certainty of evidence. Our primary outcome was revision rate and secondary outcomes was anterior knee pain rate. Outcomes were pooled using the random-effect model and presented as risk ratio (RR), or mean difference (MD), with 95% confidence interval (CI).

RESULTS

Fifty studies (5586 knees) were included. Significant reductions in patellar revision rate (RR 0.41, 95% CI [0.19, 0.88]; P = 0.02; I²  = 24.20%) and non-patellar revision rate (RR 0.64, 95% CI [0.55, 0.75]; P < 0.001; I²  = 0%) were seen after patellar resurfacing. Patellar resurfacing significantly reduced the anterior knee pain rate than nonresurfacing (RR 0.72, 95% CI [0.57, 0.91]; P = 0.006; I²  = 69.5%). Significant differences in patient-reported outcome measures were found. However, these differences were inconsistent and lacked clinical importance. Patellar resurfacing resulted in a significant lower rate of patellar clunk (RR 0.58, 95% CI [0.38, 0.88]; P = 0.01; I²  = 0%), a higher patellar score (MD 1.24, 95% CI [0.67, 0.81]; P < 0.001; I²  = 73.8%), but prolonged surgical time (MD 8.59, 95% CI [5.27, 11.91]; P < 0.001; I²  = 88.8%).

CONCLUSIONS

The clear relationship is that patellar resurfacing reduces revisions, anterior knee pain, and patellar clunk. It will be interesting to compare the initial cost with the revision cost when required and cost-utility analysis with long-term results in future studies.

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

BACKGROUND

Despite growing evidence in the literature, there is still a lack of consensus regarding the use of the mobile-bearing (MB) design total knee arthroplasty (TKA).

METHODS

In a prospective, comparative, randomised, single centre trial, 106 patients with end-stage osteoarthritis of the knee were randomised to either an MB or fixed-bearing (FB) group to receive posterior stabilised (PS)-TKA using a standard medial parapatellar approach and patellar resurfacing with follow-up (FU) for 5 years. The primary outcome was anterior knee pain (AKP) during the chair rise test and the stair climb test 5 years after surgery. The secondary outcome was the ability to rise from a chair and to climb stairs, range of motion (ROM), Knee Society Score (KSS), RAND-36 scores and radiological analysis of the patellar tilt.

RESULTS

No statistically significant difference was found between the two groups at 5 years FU in terms of median AKP during the chair rise test and the stair climb test (p = 0.5 and p = 0.8, respectively). There was no significant difference in any of the other secondary outcome parameters between the groups at 5 years FU.

CONCLUSION

A mobile-bearing TKA does not decrease AKP compared to fixed bearings.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT02892838 .

LEVEL OF EVIDENCE

II.

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.