The Rotaglide mobile-bearing total knee arthroplasty: no difference between cemented and hybrid implantation

Patella is rarely resurfaced during primary total knee arthroplasty in clinical trials conducted in Greece: a systematic review

PURPOSE

The aim of the present study was to report the approach of Greek surgeons regarding patellar management and provide the outcomes and the rate of the need for secondary patella resurfacing.

METHODS

Following the PRISMA guidelines, PubMed, Scopus, and The Cochrane Central Register of Controlled Trials (CENTRAL) databases were accessed in January 2024. Clinical studies evaluating the outcomes of patients undergoing primary TKA were considered eligible for this systematic review if the following predefined criteria were fulfilled: (1) published in English, (2) were conducted in Greece, and had a minimum of 2-year follow-up. The methodological quality and publication bias were assessed using the Modified Coleman Methodology Score (mCMS) and ROBIS tool, respectively. Data was presented in tables using absolute values from individual studies. Pooled data were presented as means, ranges, and percentages.

RESULTS

Six clinical studies with a total of 1084 TKAs were included. Four studies were retrospectives, and two studies were prospective. Patella was only resurfaced in 0.6% of total TKAs. TKA without patellar resurfaced, which resulted in an improvement in functional outcome. Among studies, the overall need for revision incidence was 7.6% (68 out of 892 TKAs). Additionally, Aseptic loosening (2.4%) was the most common reason for revision due to patellofemoral joint complications, followed by secondary patellar resurfacing (2.1%) and deep infection (1.3%). The mean mCMS demonstrated a fair methodological quality level, and the ROBIS toll a low risk of bias in all four domains.

CONCLUSION

The available evidence supports that Greek surgeons mainly do not resurface the patella. However, patellar non-resurfacing yields good functional outcomes and presents relatively low revision rates for secondary patellar resurfacing.

LEVEL OF EVIDENCE

IV.

Uncemented trabecular metal high-flex posterior-stabilized monoblock total knee arthroplasty in patients aged 60 years or younger

BACKGROUND

Uncemented trabecular metal (TM) monoblock tibial components in total knee arthroplasty (TKA) have shown excellent clinical results for up to 10 years. However, these studies were performed in highly specialized units, with few surgeons and often excluding knees with secondary osteoarthritis (OA), severe malalignments and previous surgery. The purpose of this study was to investigate implant survivorship and clinical and radiological outcome of the uncemented TM high-flex posterior stabilized (PS) monoblock tibial component in routine clinical practice.

METHODS

A retrospective study of 339 knees (282 patients) operated with the implant in routine clinical practice at two hospitals on patients aged 60 years or younger between 2007 and 2015. The operations were performed by 12 surgeons and there were no specific contraindications for use of the implant. Follow up ended in 2020. The status of the implant of deceased patients at death and those not attending follow up was checked with the Swedish Knee Arthroplasty Register. Clinical follow up consisted of clinical investigation, PROMs, and knee X-ray.

RESULTS

Follow up was mean (range) 8.5 (5-13.8) years, and the 8-year survival rate was 0.98 (standard error 0.007). Five patients five knees) were deceased, five knees were revised (none due to aseptic loosening), and 16 patients did not attend the clinical follow up. Forty-four percent of the knees had secondary OA and 45% had had previous operations. 93% were satisfied or very satisfied with the operation and forgotten joint score (FJS) was median (interquartile range) 81 (44-94). Radiographic analysis revealed bone in close contact with the tibial tray and pegs in most cases, and in only 2% of the knees were potential radiolucent lines found.

CONCLUSION

The results indicate that this uncemented implant performs excellently in routine clinical practice and also in younger patients with secondary OA or previous knee operations.

Hybrid fixation versus full-cemented or full-cementless fixation in total knee arthroplasty: Systematic review and meta-analysis of comparative studies

OBJECTIVE

Hybrid fixation is one alternative to full-cemented fixation in total knee arthroplasty (TKA) with theoretical advantages. Hybrid fixation may offer the advantages of cementless femoral fixation, while also avoiding the problem of tibial loosening in full-cementless TKA. The purpose of the study is to determine whether hybrid TKA may perform comparably to or better than full-cemented and full-cementless TKA.

METHODS

We searched the MEDLINE, EMBASE and Cochrane Library databases through September 2018 for randomized controlled trials and observational studies comparing outcomes of hybrid versus full-cemented or full-cementless fixation techniques. Outcomes of interest included aseptic loosening, overall reoperation rate, infection, radiolucent lines and operating time. Data were pooled with the Mantel-Haenszel random effects model.

RESULTS

We included 14 studies with follow-up ranging from 2.7 to 9.6 years in our quantitative analysis, of which 7 studies compared hybrid fixation with full-cemented TKA and another 7 compared hybrid fixation with full-cementless TKA. Combined data revealed that the hybrid fixation group had a similar rate of aseptic loosening compared with cemented (P = 0.19) and cementless (P = 0.49) groups. There was no difference with respect to other outcomes, including overall reoperation rate, infection, radiolucent lines and operating time between groups.

CONCLUSION

Hybrid, cementless and cemented TKAs have comparable mid-term results as it pertains to aseptic loosening, overall reoperation, infection, radiolucent lines and operating time. Further comparative studies are needed to investigate these potential effects over the long-term.

Cemented vs Uncemented Femoral Components: A Randomized, Controlled Trial at 10 Years Minimum Follow-Up

BACKGROUND

The type of total knee arthroplasty (TKA) fixation (cemented or uncemented) is still subject to debate. The aim of this study is to assess the survival rate, clinical outcomes, and radiological results of TKA according to the fixation type.

METHODS

A total of 130 patients were randomly assigned to either the cement group (cemented femoral and tibial implants) or the hybrid group (cemented tibial implant, uncemented femoral implant). The inclusion criteria were patients between 50 and 90 years old who underwent primary TKA for osteoarthritis between 2004 and 2005 without a history of open knee surgery. Revisions and complications were reported, as well as clinical scores and radiological signs of loosening.

RESULTS

One hundred eighteen patients had complete data at 10 years of minimum follow-up (59 in each group). The mean age was 72 years old. The mean follow-up was 13 years. The survival rate was 98% at 13 years in both groups (1 aseptic loosening at 2 years in the cement group, 1 septic loosening in the hybrid group). The complication rate in the cement group was 8.5% (n = 5) vs 12.1% (n = 7) in the hybrid group (P = .8). The clinical results were not significantly different. In the cement group, 25% of patients (n = 15) had radiolucent lines at 10 years. In the hybrid group, 33% of patients had bone transparencies, not evolving or symptomatic.

CONCLUSION

At a minimum follow-up of 10 years, there were no significant differences between cemented TKA and hybrid TKA for the survivorship, the complication rate, the clinical scores, or the radiological signs of loosening.

LEVEL OF EVIDENCE

I.

Comparative assessment of different reconstructive techniques of distal femur in revision total knee arthroplasty

PURPOSE

Bone loss is often encountered in revision total knee arthroplasty. In particular, when the cortex of distal femur is breached, the surgical decision on the reconstructive options to be taken is challenging due to the variety of defects and the lack of data from clinical or experimental studies that can support it. The aim of the present work was to test the hypothesis that for an identical defect and bone condition, each reconstructive technique option has a dissimilar stress and stability behaviour, which may be related to differing longevity of the revision procedure.

METHODS

Triaxial strain gauges and video extensometer were used to measure distal cortex strains and implant stability in eight reconstructive techniques replicated with synthetic femur under a load of 2030N. To assess the cancellous bone strains, finite element models were developed and validated.

RESULTS

The measured strains showed that the distal cortex is not immune to the different reconstructive techniques, when applied to an identical defect; however, significant differences (P < 0.05) were found only between bone graft and metal augment on the 12-mm larger distal defect. The stem addition improves the stability of all reconstructive techniques; however, significant differences (P = 0.03) were found only on the bone-graft technique.

CONCLUSIONS

Cement-fill and metal-augment techniques, applied to the 4-mm smaller defect, are not associated with different structural behaviour, while for the 12-mm larger defect, the metal-augment and bone-graft techniques presented distinct biomechanical effects. These effects, by themselves, may not be sufficient to be associated with a different longevity of the revision procedure among techniques, when the stem is added to the bone-graft technique. These findings, based on independent scientific understanding and advanced prediction tools, can improve the surgical decision-making process, when the peripheral cortex of the distal femur is breached.

Comparison of ultra-congruent mobile- and fixed-bearing navigation-assisted total knee arthroplasty with minimum 5-year follow-up

PURPOSE

The purpose of this study was to compare the midterm outcomes between fixed and mobile ultra-congruent (UC) bearings in total knee arthroplasty (TKA).

METHODS

This is a retrospective matched-pairs case-control study of patients who underwent primary navigation-assisted TKA with a minimum 5-year follow-up. A total of 182 cases involved the fixed UC bearing system as Group 1 and 101 cases involved mobile UC bearing system group as Group 2. After 1:1 matching, 73 knees in each group were enrolled. Clinical and radiographic outcomes were evaluated.

RESULTS

The overall survival was 143 of 146 cases (97.9 %) at final follow-up, and 72 of 73 cases (96.3 %) in Group 1 and 71 of 73 cases (95.8 %) in Group 2 at final follow-up based on an endpoint of revision surgery. The reasons of revision TKA were periprosthetic fracture in Group 1, infection and bearing dislocation in Group 2. There was no statistical difference in Hospital for Special Surgery (HSS) scores, Knee Society Scores (KSS), WOMAC index score evaluations between groups.

CONCLUSIONS

This study demonstrated that the fixed-bearing UC prosthesis could provide satisfactory performance compared with that of the mobile-bearing UC prosthesis with minimum 5-year follow-up. The fixed-bearing UC prosthesis could be considered in navigation-assisted TKA with theoretical advantages of UC design.

LEVEL OF EVIDENCE

IV.

Extent of vertical cementing as a predictive factor for radiolucency in revision total knee arthroplasty

PURPOSE

Limited information is available regarding the effects of cementing extent on implant stability in patients who have undergone revision total knee arthroplasty (TKA). As such, the goals of this study were: (1) to determine the correlation between the extent of vertical cementing and implant loosening; (2) to determine whether the extent of cementing is a potential predictive factor for radiolucency; and (3) to evaluate the minimal amount of cement needed for a stable implant during revision TKA using a hybrid technique.

METHODS

One hundred nine stemmed/revision TKAs with a mean follow-up period of 5 years were retrospectively analysed. In each case, a single varus-valgus constrained implant was used and fixed with a hybrid technique. Implant stability was evaluated according to the modified Knee Society radiographic scoring system. The extent of vertical cementing was defined as the longitudinal length from the implant base to the end of the radiopaque line around the stem on radiograph. Its correlation with implant stability was analysed, and the minimal value for a stable implant was evaluated with a receiver operating characteristic (ROC) analysis.

RESULTS

The mean extent of vertical cementing was longer in stable implants (femur: p = 0.001, tibia: p = 0.004) and significantly correlated with implant stability (femur: p < 0.001, tibia: p = 0.001). A logistic regression analysis revealed that the risk of loosening was 8.7-16.1 times higher when the extent of cementing was <40 mm, which was located at the stem-implant junction of the modular implant. The minimal extent of vertical cementing was estimated to be 60 mm for a stable femoral implant and 50 mm for a tibial implant.

CONCLUSIONS

The hybrid fixation technique with a cementing extent >60 mm for the femur and 50 mm for the tibia was durable at a mean follow-up period of 5 years. Vertical cementing 10-20 mm above the stem-implant junction is recommended when performing revision TKA using this technique.

LEVEL OF EVIDENCE

IV.

No differences in clinical outcomes between fixed- and mobile-bearing computer-assisted total knee arthroplasties and no correlations between navigation data and clinical scores

PURPOSE

The theoretical advantages of mobile-bearing (MB) designs over the conventional fixed bearings (FBs) for total knee arthroplasty (TKA) have not been proved yet through clinical studies. The aim of the study was to test whether the MB design has advantages in terms of better clinical outcomes when compared to FB. Furthermore, the relationships between intra-operative obtained implant positioning data and the clinical scores were analysed.

METHODS

A total of 99 patients were randomized into the FB or the MB group. All patients received the same posterior cruciate retaining implants and were operated with the use of a computer-assisted navigation system. The clinical outcomes of both groups were compared pre-operatively, at 1 year, and at a mean follow-up time of 4 years after surgery.

RESULTS

The MB implants showed no advantages over the FB when comparing the Knee Society Scores, the Oxford Score, the range of movement (ROM) and pain intensity of the patients in both groups at 1 and 4 years after surgery. There were no relationships between the computer navigation data and the clinical scores.

CONCLUSIONS

In view of the 4-year results, there is no evidence to support the recommendation of one design over the other in terms of better clinical outcome scores, higher ROM or lower pain rates. Long-term follow-up results may be necessary, including survival rates. Further research comparing different TKA designs should also include standardized performance-based tests.

LEVEL OF EVIDENCE

Prospective study (Randomized controlled trial with adequate statistical power to detect differences), Level I.