Similar migration in computer-assisted and conventional total knee arthroplasty

6-month migration sufficient for evaluation of total knee replacements: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

This updated meta-analysis evaluates the migration pattern of the tibial component of primary total knee replacements measured with radiostereometric analysis (RSA). We aimed to evaluate whether 6-month maximum total point motion (MTPM) values could be used instead of 1-year MTPM for RSA threshold testing and to present the pooled migration patterns for different implant designs that can be used as a benchmark.

PATIENTS AND METHODS

The search included all published RSA studies on migration patterns of tibial components until 2023. Study groups were classified according to their prosthesis brand, fixation, and insert (PFI). Sub-analyses were performed to compare the mean tibial component migration patterns of different implant variables, stratified according to fixation.

RESULTS

96 studies (43 new studies), including 197 study groups and 4,706 knees, were included. Most migration occurred within the first 6 postoperative months (126 study groups: mean 0.58 mm, 95% confidence interval [CI] 0.50-0.65), followed by minimal migration between 6 and 12 months (197 study groups: mean 0.04 mm, CI 0.03-0.06), irrespective of the fixation method used. Distinct migration patterns were observed among the different fixation methods. No differences were found in migration patterns among cemented components in any of the sub-group analyses conducted. For uncemented implants, trabecular metal surfaced components seemed to migrate less than porous-coated or uncoated components Conclusion: Based on the small difference between MTPM values at 6 months and 1 year, MTPM at 6 months could be used instead of MTPM at 1 year for RSA threshold testing. The pooled migration patterns can be used as benchmark for evaluation of new implants by defining fixation-specific RSA thresholds when combined with implant survival.

Computerized Navigation: A Useful Tool in Total Knee Replacement

The purpose of computer assistance in a total knee replacement is to achieve optimal alignment, size, and positioning of the implant. The method is safe and accurate and may be particularly useful in cases with abnormal anatomy.

Use of National Joint Registries to Evaluate a New Knee Arthroplasty Design

BACKGROUND

The introduction of new technology in joint replacement surgery requires close monitoring to identify early successes and failures. This monitoring can be effectively performed through the analysis of registry data and radiostereometric analysis studies. This study examined the revision rates of a contemporary knee system for total knee arthroplasty (TKA) using National Joint Replacement Registries.

METHODS

A review of the literature was performed to identify comparative studies and registry databases reporting the revision rates of a specific contemporary knee design between 2013 and 2018. The total number of TKA cases performed using this implant was recorded. The latest follow-up or duration of monitoring through a registry database was used to report implant survivorship.

RESULTS

There were 4 registry databases and 1 comparative study reporting the revision rates of the contemporary knee system. A total of 41,483 cases were identified with a follow-up range of 1.5-5.0 years. The all-cause revision rate ranged from 0.7% to 2.5% at latest follow-up. This was comparable to all-cause revision rates of other knee systems reported in the registries, ranging from 0.8% to 5.6% over similar follow-up periods.

CONCLUSIONS

Evaluation of data from multiple national joint registries demonstrated the revision rate for this contemporary knee system to be comparable to other TKA systems at latest follow-up. None of the registries have identified any concerning rates of revision compared to other devices at this length of follow-up. National Joint Registries are an important resource in evaluating the short-term, mid-term, and long-term results of new implant designs introduced to the market.

Does Accelerometer-based Navigation Have Any Clinical Benefit Compared with Conventional TKA? A Systematic Review

BACKGROUND

Accelerometer-based navigation is a handheld navigation tool that was introduced to offer a simpler technique compared with more-cumbersome computer-assisted surgery (CAS). Considering the increasing number of adopters, it seems important to evaluate the potential clinical benefits of this technology compared with conventional TKA.

QUESTIONS/PURPOSES

In this systematic review, we asked: (1) Is accelerometer-based navigation more accurate than conventional TKA? (2) Does accelerometer-based navigation provide better functional outcome than conventional TKA? (3) Does accelerometer-based navigation increase surgical time or decrease the risk of complications or reoperations compared with conventional TKA?

METHODS

This systematic review included all comparative prospective and retrospective studies published in the MEDLINE/PubMed and Cochrane libraries over the last 10 years. Inclusion criteria were all studies in English that compared accelerometer-based navigation with conventional TKA. Eleven studies met these criteria with 621 knees in accelerometer-based navigation group and 677 knees in conventional TKA group. Results related to alignment, objective and subjective functional scores, duration of surgery, complications and reoperations were extracted and compared between accelerometer-based-navigation and conventional TKA. Methodological quality was assessed using Methodological Index for Non-Randomized Studies (MINORS) tool (for nonrandomized control trials) and Cochrane Risk of Bias (for randomized control trials (RCTs). All studies with fair or better quality were included. Four RCTs and six nonrandomized studies comparing accelerometer-based navigation to conventional TKA were found.

RESULTS

Inconsistent evidence on mechanical axis alignment was found, with five of nine studies slightly favoring the accelerometer-based navigation group, and the other four showing no differences between the groups. Only two of eight studies favored accelerometer-based navigation in terms of tibial component alignment in the coronal plane; the other six found no between-group differences. Similarly, mixed results were found regarding other metrics related to component alignment; a minority of studies favored accelerometer-based navigation by a small margin, and most studies found no between-group differences. Only three studies evaluated functional outcome and none of them showed a difference in range of motion or patient-reported outcomes. Most studies, six of seven, found no between-group differences concerning surgical time; one study demonstrated a slight increase in time with accelerometer-based navigation. There were no between-group differences in terms of the risk of complications, which generally were uncommon in both groups, and no reoperations or revisions were reported in either group.

CONCLUSIONS

We found conflicting evidence about whether accelerometer-based navigation reduces the number of coronal-plane outliers or improves alignment to a clinically important degree, and we found no evidence that it improves patient-reported outcomes or reduces the risk of complications or reoperations. Accelerometer-based navigation may increase surgical time. The overall quality of the evidence was low, which suggested that any observed benefits were overestimated. Given the absence of higher-quality evidence demonstrating compelling benefits of this accelerometer-based navigation technology, it should not be widely adopted.

LEVEL OF EVIDENCE

Level III, therapeutic study.

The assessment of the stability of the tibial component of a novel knee arthroplasty system using radiostereometric analysis

Aims

The introduction of a novel design of total knee arthroplasty (TKA) must achieve outcomes at least as good as existing designs. A novel design of TKA with a reducing radius of the femoral component and a modified cam-post articulation has been released and requires assessment of the fixation to bone. Radiostereometric analysis (RSA) of the components within the first two postoperative years has been shown to be predictive of medium- to long-term fixation. The aim of this study was to assess the stability of the tibial component of this system during this period of time using RSA.

Patients and Methods

A cohort of 30 patients underwent primary, cemented TKA using the novel posterior stabilized fixed-bearing (ATTUNE) design. There was an even distribution of men and women (15:15). The mean age of the patients was 64 years (sd 8) at the time of surgery; their mean body mass index (BMI) was 35.4 kg/m 2 (sd 7.9). RSA was used to assess the stability of the tibial component at 6, 12, and 24 months compared with a six-week baseline examination. Patient-reported outcome measures were also assessed.

Results

The mean maximum total point motion (MTPM) of the tibial component between 12 and 24 months postoperatively was 0.08 mm (sd 0.08), which is well below the published threshold of 0.2 mm (p < 0.001). Patient-reported outcome measures consistently improved.

Conclusion

The tibial component of this novel design of TKA showed stability between assessment 12 and 24 months postoperatively, suggesting an acceptably low risk of medium- to long-term failure due to aseptic loosening.

Computer-Assisted Compared with Conventional Total Knee Replacement: A Multicenter Parallel-Group Randomized Controlled Trial

BACKGROUND

We previously reported the short-term radiographic and functional results of a randomized controlled trial (RCT) comparing computer-assisted and conventionally performed total knee replacement. We currently report the 2-year clinical results from this trial.

METHODS

One hundred and ninety patients were randomly allocated to undergo either computer-assisted or conventional total knee replacement. One hundred and seventy-two patients were available for clinical evaluation at 2 years, and 167 (97%) of those answered all patient-reported outcome measures (PROMs), including the Knee Injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Society Score (KSS), visual analog scale (VAS), and EuroQol-5 Dimensions (EQ-5D). Patients and clinical evaluators were blinded to the method of surgery. Surgical outcome was assessed using the Outcome Measures in Rheumatology-Osteoarthritis Research Society International (OMERACT-OARSI) criteria to calculate responder rates, divided into high responders, moderate responders, and nonresponders.

RESULTS

The computer-assisted group had significantly more improvement than the conventional group in the mean scores for 2 subscales of the KOOS (7.4 for symptoms [p = 0.02] and 16.2 for sport and recreation [p < 0.01]) and in 1 subscale of the WOMAC (8.8 for stiffness [p = 0.03]).The computer-assisted group also had significantly more high responders (82.8%) than the conventional group (68.8%; p = 0.03) at 2 years, with the number needed to treat determined to be 8.

CONCLUSIONS

In this study, the use of computer navigation provided better pain relief and restored better function than the use of the conventional surgical technique at 2 years after total knee replacement.

LEVEL OF EVIDENCE

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

Computer assisted total knee arthroplasty: a real navigation to better results?

BACKGROUND AND AIM OF THE WORK

Computer assisted surgery in knee replacement is still in discussion, but majority of papers affirm an increase of the accuracy in alignment. Aim of our study is to evaluate the accuracy of mechanical axis, the posterior tibial slope and the femoral component rotation with navigation, x-ray and CT data.

METHODS

We have analysed 145 patients who underwent total knee arthroplasty between January 2012 and December 2014. We have checked each patient at 6, 12 and 24 months of follow-up. During each visit, we did a clinical evaluation checking the ROM and a clinical score (KOOS). At 2 years, we did a CT evaluation and a plain x-ray evaluation.

RESULTS

125 patients have completed the follow-up. Mean follow-up time was 2,6 years. Both ROM and KOOS values increased during follow-up. About the mechanical axis, both x-ray and CT data showed a mean deviation <2° from the target. About posterior tibial slope and femoral component rotation, CT data showed a mean deviation of <3° from the target. Mean difference between navigation and CT data was <1°.

CONCLUSIONS

According to literature data, our data confirm that computer assisted surgery in knee replacement have a good accuracy of coronal alignment, rotational alignment and posterior tibial slope.

Computer assisted total knee arthroplasty: a real navigation to better results?

BACKGROUND AND AIM OF THE WORK

Computer assisted surgery in knee replacement is still in discussion, but majority of papers affirm an increase of the accuracy in alignment. Aim of our study is to evaluate the accuracy of mechanical axis, the posterior tibial slope and the femoral component rotation with navigation, x-ray and CT data.

METHODS

We have analysed 145 patients who underwent total knee arthroplasty between January 2012 and December 2014. We have checked each patient at 6, 12 and 24 months of follow-up. During each visit, we did a clinical evaluation checking the ROM and a clinical score (KOOS). At 2 years, we did a CT evaluation and a plain x-ray evaluation.

RESULTS

125 patients have completed the follow-up. Mean follow-up time was 2,6 years. Both ROM and KOOS values increased during follow-up. About the mechanical axis, both x-ray and CT data showed a mean deviation <2° from the target. About posterior tibial slope and femoral component rotation, CT data showed a mean deviation of <3° from the target. Mean difference between navigation and CT data was <1°.

CONCLUSIONS

According to literature data, our data confirm that computer assisted surgery in knee replacement have a good accuracy of coronal alignment, rotational alignment and posterior tibial slope.