Seventeen to Twenty Years of Follow-Up of the Low Contact Stress Rotating-Platform Total Knee Arthroplasty With a Cementless Tibia in All Cases

Central cone design demonstrates greater micromotion compared to keel design in cementless tibial baseplates: A biomechanical analysis

PURPOSE

The purpose of this study was to compare micromotion of two new cementless tibial baseplates to a cementless design with well-published clinical success.

METHODS

Three cementless tibial baseplate designs (fixed-bearing [FB] with keel and cruciform pegs, rotating-platform with porous central cone and pegs, FB with cruciform keel and scalloped pegs) were evaluated on sawbone models. Loading was applied to the baseplate at a rate of 1 Hz for 10,000 cycles, which represents 6-8 weeks of stair descent. This time frame also represents the approximate time length for the induction of biologic fixation of cementless implants. Compressive and shear micromotion at the sawbone-implant interface were measured.

RESULTS

At the end of the loading protocol, the central cone rotating-platform design exhibited greater micromotion at the anterior (p < 0.001), posterior (p < 0.001) and medial locations (p = 0.049) compared to the other two implants. The central cone design also exhibited greater translational micromotion in the sagittal plane at the medial (p = 0.001) and lateral locations (p = 0.034) and in the coronal plane anteriorly (p = 0.007).

CONCLUSION

The cementless central cone rotating-platform baseplate demonstrated greater vertical and translational micromotion compared to the two FB baseplates with a keel underloading. This may indicate lower initial mechanical stability in implants without a keel, which possibly affects osseointegration. The implication of this is yet unknown and requires further long-term clinical follow-up to correlate these laboratory findings.

LEVEL OF EVIDENCE

V (biomechanical study).

Comparison of the effect of open-box versus closed-box prostheses on blood loss following total knee arthroplasty: a meta-analysis

Purpose

Postoperative blood loss is a common complication following total knee arthroplasty (TKA). The authors aimed to analyze the significance of open versus closed-box prostheses in reducing blood loss after TKA.

Methods

PubMed, Cochrane, Scopus, and Web of Science were searched. Observational studies and clinical trials comparing the effect of open-box versus closed-box prostheses on blood loss following TKA were included. The primary outcome was total blood loss following TKA. Secondary outcomes included average transfused units and total operation time. Continuous data were represented as mean difference (MD) and CI, while dichotomous data were presented as odds ratio (OR) and CI. RevMan software version 5.4 was used to conduct the analysis.

Results

Four studies with a total number of 687 patients were included. The pooled analysis showed a statistically significant association between closed-box and decreased total blood loss following TKA compared with open-box (MD=173.19, 95% CI=88.77-257.61, P value <0.0001). Similar findings were reported in unilateral TKA (MD=190.63, 95% CI=70.91-310.35, P value=0.002), and bilateral TKA (MD=160.79, 95% CI=61.70-359.86, P value=0.001). There was no significant difference between open and closed-box regarding average transfused units (MD=0.02, 95% CI=-0.07-0.11, P value=0.68), blood transfusion rate (OR=1.38, 95% CI=0.85-2.26, P value=0.20), length of stay (MD=0.06, 95% CI=-0.27 to 0.38, P value=0.74), and total operation time (MD=1.08, 95% CI=-4.62 to 6.79, P value=0.71).

Conclusion

Closed-box reduces the total blood loss following unilateral and bilateral TKA. More studies are warranted to explore the benefits of Closed-box in patients with high bleeding susceptibility.

Is Cementless Total Knee Arthroplasty Safe in Women Over 75 Y of Age?

BACKGROUND

Cementless total knee arthroplasty (TKA) is the subject of renewed interest. Previous concerns about survivorship have been addressed and there is an appeal in terms of biological fixation and surgical efficiency. However, even surgeon advocates have concerns about the risk of marked subsidence when using this technology in older patients at risk for osteoporosis.

METHODS

This was a retrospective analysis of 1,000 consecutive fully cementless mobile bearing TKAs performed at a single institution on women over 75 years of age who had postoperative and 1-year x-rays. The primary outcome was the incidence of subsidence.

RESULTS

There were three asymptomatic cases with definite subsidence and change in alignment. In a fourth symptomatic case, the femoral component subsided into varus and the tibia into valgus, thus maintaining alignment which facilitated nonoperative treatment in a 92-year-old. Overall, at 1 year, there were two- liner revisions for infection without recurrence. Five patients had further surgery, of which three were washouts and two were for periprosthetic fractures sustained postoperatively within 1 year. Seven patients had further anesthesia, of which five were manipulations and two were nonrecurrent closed reductions for spinouts.

CONCLUSION

Cementless TKA did not have a high risk of subsidence in this at-risk population. In the hands of experienced surgeons, these procedures can be used safely irrespective of bone quality.

Cementless Total Knee Arthroplasty Over the Past Decade: Excellent Survivorship in Contemporary Designs

BACKGROUND

Cementless fixation in total knee arthroplasty (TKA) is re-emerging due to improvements in biomaterials, surgical technique, and implant design. Albeit rare, failure of osseointegration typically occurs within the first 2 years, and limited data exist on survivorship of the modern cementless TKA designs. This study evaluated clinical survivorship of 2 contemporary cementless TKA designs at minimum 2-year follow-up.

METHODS

A total of 627 cementless TKAs were performed up to July 2022. Three hundred thirty-nine cases were eligible for 2-year follow-up. Indications centered around bone quality and involved predominantly younger patients. The 2 designs consisted of tibial components with a highly porous titanium ingrowth surface, a central keel, and peripheral cruciform pegs with a porous cobalt-chromium femur. Survivorship estimates were calculated using right-censored non-parametric Kaplan-Meier methodologies. A total of 226 TKAs obtained minimum 2-year follow-up with a mean of 3.6 years (range, 2 to 10).

RESULTS

The all-cause revision rate was 2.4% (8 of 339). The revision rate due to aseptic loosening was 0.6% (2 of 339) consisting of 2 femoral components. No tibial components were revised for aseptic loosening. Kaplan-Meier survivorship free from aseptic loosening was 99% (95% confidence interval 98 to 100) at a maximum of 10 years.

CONCLUSION

These results demonstrate encouraging survivorship of cementless fixation in primary TKA with use of contemporary ingrowth biomaterials and modern implant designs. This particular tibial implant design with a highly porous titanium fixation surface, central keel, and peripheral cruciform pegs demonstrated excellent clinical survivorship without failure which may portend superior fixation.

LEVEL OF EVIDENCE

IV-case series, no control group/historical control group.

A randomized controlled trial comparing two-year postoperative femoral and tibial migration of a new and an established cementless rotating platform total knee arthroplasty

AIMS

The primary aim of this study was to compare the migration of the femoral and tibial components of the cementless rotating platform Attune and Low Contact Stress (LCS) total knee arthroplasty (TKA) designs, two years postoperatively, using radiostereometric analysis (RSA) in order to assess the risk of the development of aseptic loosening. A secondary aim was to compare clinical and patient-reported outcome measures (PROMs) between the designs.

METHODS

A total of 61 TKAs were analyzed in this randomized clinical RSA trial. RSA examinations were performed one day and three, six, 12, and 24 months postoperatively. The maximal total point motion (MPTM), translations, and rotations of the components were analyzed. PROMs and clinical data were collected preoperatively and at six weeks and three, six, 12, and 24 months postoperatively. Linear mixed effect modelling was used for statistical analyses.

RESULTS

The mean MTPM two years postoperatively (95% confidence interval (CI)) of the Attune femoral component (0.92 mm (0.75 to 1.11)) differed significantly from that of the LCS TKA (1.72 mm (1.47 to 2.00), p < 0.001). The Attune femoral component subsided, tilted (anteroposteriorly), and rotated (internal-external) significantly less. The mean tibial MTPM two years postoperatively did not differ significantly, being 1.11 mm (0.94 to 1.30) and 1.17 mm (0.99 to 1.36, p = 0.447) for the Attune and LCS components, respectively. The rate of migration in the second postoperative year was negligible for the femoral and tibial components of both designs. The mean pain-at-rest (numerical rating scale (NRS)-rest) in the Attune group was significantly less compared with that in the LCS group during the entire follow-up period. At three months postoperatively, the Knee injury and Osteoarthritis Outcome Physical Function Shortform score, the Oxford Knee Score, and the NRS-activity scores were significantly better in the Attune group.

CONCLUSION

The mean MTPM of the femoral components of the cementless rotating platform Attune was significantly less compared with that of the LCS design. This was reflected mainly in significantly less subsidence, posterior tilting, and internal rotation. The mean tibial MTPMs were not significantly different. During the second postoperative year, the components of both designs stabilized and low risks for the development of aseptic loosening are expected.Cite this article: Bone Joint J 2023;105-B(2):148-157.

Modern cementless posterior stabilized mobile-bearing total knee arthroplasty shows comparable clinical and radiographical results to its cemented predecessor at 1-year follow-up

PURPOSE

The purpose of this study was to evaluate perioperative and short-term clinical and radiographical results of a modern PS mobile-bearing cementless TKA system.

METHODS

A retrospective review of a consecutive series of TKAs was performed by a single surgeon using a cementless or cemented TKA of the same design (Attune, DePuy Synthes, Massachusetts, USA). The 2011 Knee Society Score, Forgotten Joint Score-12, Hip-Knee-Ankle angle, and the presence of radiolucent lines (RLLs) were reviewed 1-year postoperatively with 1:1 matching performed for age, gender, body mass index, and preoperative UCLA score. Fisher's exact test or independent Student's t-test were used for statistical analyses.

RESULTS

Forty-five cementless and 45 cemented TKAs were reviewed after 1:1 matching. The mean operative time was 8.8 min shorter (P < .01), and the mean amount of drainage was 40.0 ml greater (P = .04) in the cementless cohort. At 1-year postoperatively, there were no significant differences in both cohorts in 2011 Knee Scores and Forgotten Joint Scores-12, with no patients requiring revision surgery (NS). The incidence of RLLs was significantly higher in cementless TKAs (51%) than that in cemented TKAs (22%, P < .01). However, the mean width of RLLs in the cementless TKAs (0.2 mm) was significantly smaller (P < .01) than that in the cemented TKAs (0.8 mm) at 1-year postoperatively with no progression.

CONCLUSION

A recently introduced cementless PS mobile-bearing TKA design demonstrated comparable postoperative and radiographical results to its cemented predecessor at 1-year follow-up.

LEVEL OF EVIDENCE

Retrospective cohort study, Level III.

Lower revision rates for cemented fixation in a long-term survival analysis of three different LCS designs

BACKGROUND

In primary Total Knee Arthroplasty (TKA), it is still not clear if cemented or uncemented fixation has the best long-term survival. The Low Contact Stress (LCS) mobile-bearing (MB) knee system was introduced in 1977. The aim of this study is to investigate the long-term survival of this design with a minimum of 15-year follow-up.

METHODS

A retrospective analysis was performed, with the primary endpoint for survival defined as revision. Cox regression analysis was performed to assess the association between type of fixation and the risk of revision, while correcting for potential confounders (diagnosis, design, age and sex).

RESULTS

1271 cases were included with inflammatory joint disease (IJD) (657 cases) and non-IJD (614 cases). TKAs were performed cemented in 522 cases and uncemented in 749 cases. A bicruciate retaining design was used in 180 cases, a rotating platform design in 174 cases and an anterior posterior glide posterior cruciate-retaining (PCR) design in 916 cases. Cumulative incidence of component revision at 15 years was 2.7% (95% CI 1.6; 4.5) for cemented and 10% (95% CI 8.1; 12.4) for uncemented TKA, respectively. The 20-year cumulative incidence was 2.9% (95% CI 1.7; 4.7) for cemented and 10.9% (95% CI 8.8; 13.4) for uncemented TKA, respectively. Age, non-IJD and PCR design were associated with a significantly higher risk of revision, regardless of the type of fixation.

CONCLUSION

Long-term survival for patients undergoing cemented or uncemented TKA using the LCS MB system revealed lower revision rates for cemented fixation. Revision risk was higher in younger, non-IJD patients who had the PCR design, regardless of the type of fixation. For the LCS MB TKA design, it is recommended to use cemented fixation.

A Short-Term Multicenter Analysis of Radiolucent Lines in a Single Uncemented Rotating Platform Implant for Total Knee Arthroplasty

Background

Uncemented total knee arthroplasty is increasing as a potential solution for aseptic loosening via biologic fixation and to increase operative efficiency. However, postoperative radiolucent lines (RLLs) remain a concern for some clinicians. We report on a multicenter analysis of these RLLs over a 2-year period to identify their incidence, progression, and clinical significance.

Material and methods

Institutional review board approval was obtained for this retrospective, multicenter case series. A total of 312 patients treated with a single cruciate-retaining, fully porous coated femoral and tibial component design were included in the study. All patients were evaluated clinically and radiographically in the early postoperative period and at final follow-up (average 2.0 years). Average age of the study group was 58.2 years, and average body mass index was 30.7. Of the total, 66% were male, and 34% were female. Two independent surgeons evaluated the radiographs at the initial postoperative visit and at the most recent follow-up for RLLs. Knee Society Scores and range of motion (ROM) were collected at each visit.

Results

We identified RLLs in 25% of patients. All RLLs were less than 1 mm in size and located at the periphery of the tibial implant. None of the RLLs were progressive. At the final follow-up, compared with early postoperative imaging, no new RLLs were identified. Average ROM in flexion was 124 degrees, and the average Knee Society Scores at the most recent clinical follow-up was 96.

Conclusion

RLLs are commonly seen following cementless TKA, most commonly underneath the tibial tray. Based on this data set, there does not appear to be progression of these RLLs with time, and they do not appear to have an effect on ROM or clinical outcome at 2 years.

[Biomechanical research on effects of pseudo-patella baja on stress of patellofemoral joint after total knee arthroplasty]

Objective

To investigate biomechanical effects of pseudo-patella baja on stress of patellofemoral joint after total knee arthroplasty (TKA) by using finite element analysis (FEA).

Methods

A series of CT and MRI of the left knee joint of two healthy volunteers and three-dimensional (3D) scanned data of TKA prosthesis were taken, and the 3D models of knee before and after TKA were established. The finite element model of pseudo-patella baja, normal patella, and alta patella after TKA were constructed by Insall-Salvafi (IS) ratio and Blackburne-Peel (BP) ratio. The load was applied along the direction of quadriceps femoris. After testing the validity of the finite element model, the high contact stress of patellofemoral joint was measured on the von Mise stress nephogram of pseudo-patella baja, normal patella, and alta patella after TKA when the knee flexion was 30°, 60°, and 90°. The average contact area was calculated according to two volunteers' data.

Results

On the finite element model of the normal patella after TKA with knee flexion 30°, 475 N pressure was applied along the direction of quadriceps femoris. The contact stress of patellofemoral joint was (1.29±0.41) MPa, which was similar to the results reported previously. The finite element model was valid. The von Mise stress nephogram showed that the stress mainly focused on the medial patellofemoral articular surface during knee flexion, and the contact point gradually moved up with the knee flexion deepened. The stress on the medial and lateral patellofemoral articular surface increased with the knee flexion deepened but decreased with the increase of patellar height. The effects of patellar height and knee flexion on the high contact stress of patellofemoral joint were similar among the finite element models after TKA based on the data of two volunteers. The high contact stress of patellofemoral joint increased with the knee flexion deepened in the same patellar height models ( P<0.05), but decreased with the increase of patellar height in the same knee flexion models ( P<0.05). The high contact stress of patellofemoral joint of pseudo-patella baja model was significantly higher than normal and alta patella models ( P<0.05). The average contact area of patellofemoral joint of pseudo-patella baja was bigger than normal and alta patella models with the knee flexion deepened.

Conclusion

The pseudo-patella baja after TKA has an important effect on the biomechanics of patellofemoral joint. Reserving the joint line and avoiding the occurrence of pseudo-patella baja can decrease the risk of anterior knee pain, patellar arthritis, and other complications caused by the increasing of contact stress of patellofemoral joint.

No clinical difference between TiN-coated versus uncoated cementless CoCrMo mobile-bearing total knee arthroplasty; 10-year follow-up of a randomized controlled trial

PURPOSE

Improvement of biomechanical properties of cobalt-chromium-molybdenum (CoCrMo) implant surface and reduction of adhesive wear is achieved by titanium-nitride (TiN) coating in vitro. Less pain, higher postoperative outcome scores and a lower revision rate after TKA with a TiN-coated CoCrMo TKA compared with uncoated CoCrMo TKA after 10-year follow-up was hypothesized.

METHODS

In a double-blinded RCT, 101 patients received a cementless mobile-bearing CoCrMo TKA, either TiN-coated or uncoated. The primary outcome measure was the visual analogue scale (VAS) score for pain and secondary outcome measures were the Knee Society Score (KSS), Oxford Knee Score (OKS), revision rate and adverse events. Patients were assessed at 6 weeks, 6 months, 1 year, 5 years and 10 years, postoperatively.

RESULTS

68 patients (67%) were available for 10-year follow-up. No difference was found in any of the assessed outcome measures with a mean decrease in VAS score (31.6 ± 22.9) and a mean increase in OKS (10.9 ± 8.4), KSS (29.3 ± 31.4), KSSK (26.4 ± 18.2) and KSSF (4.1 ± 22.9). Overall revision rate was 7% (coated 6% vs uncoated 8%) without additional revision procedures between 5 and 10-year follow-up.

CONCLUSIONS

The in vitro potential benefits of TiN coating did not result in better clinical outcome when compared to an uncoated cementless TKA. Pain, functional outcome and revision rates were comparable after 10-year follow-up. TiN-coated cementless TKA provides comparable good long-term results, similar to uncoated cementless CoCrMo TKA.

LEVEL OF EVIDENCE

Level 1, Therapeutic Study NETHERLANDS TRIAL REGISTER: NL2887/NTR3033.

[Progress of change in bone mineral density after knee arthroplasty]

Objective

To summarize research progress of change in bone mineral density (BMD) after knee arthroplasty and its diagnostic methods, influencing factors, and drug prevention and treatment.

Methods

The relevant literature at home and abroad was reviewed and summarized from research status of the advantages and disadvantages of BMD assessment methods, the trend of changes in BMD after knee arthroplasty and its influencing factors, and the differences in effectiveness of drugs.

Results

The central BMD and mean BMD around the prosthesis decrease after knee arthroplasty, which is closely associated with body position, age, weight, daily activities, and the fixation methods, design, and material of prosthesis. Denosumab, bisphosphonates, and teriparatide et al. can decrease BMD loss after knee arthroplasty.

Conclusion

BMD after knee arthroplasty decreases, which is related to various factors, but the mechanism is unclear. At present, some inhibitors of bone resorption can decrease BMD loss after knee arthroplasty. However, its long-term efficacy remains to be further explored.

Current Evidence-based Indications for Modern Noncemented Total Knee Arthroplasty

Total knee arthroplasty (TKA) is one of the most common procedures performed in orthopaedic surgery. Traditionally, most TKAs have been performed by cementing the implant to the bone with polymethyl methacrylate to provide fixation. Noncemented implants that rely on boney ingrowth for fixation are increasingly appealing to surgeons, given success in total hip arthroplasty and the desire for long-term stability of implants in younger patients. Despite high failure rates with early designs, several series of recent designs have demonstrated improved survivorship, although this has not been confirmed in larger registry studies. Modern screwless designs with improved porous coating are thought to contribute to better ingrowth and have been designed to address previous implant pitfalls. Surgeons must be aware of the potential advantages and limitations of noncemented TKA.

Cementless Fixation for Total Knee Arthroplasty in Various Patient Populations: A Literature Review

The number of total knee arthroplasties (TKAs) performed in the United States has increased considerably in recent years, with a major contribution from younger patients. Maximizing survivorship of these implants has always been a point of emphasis. Early TKA designs with cementless fixation were associated with high rates of complications and implant failures. However, recent advances in cementless designs have shown excellent results. The decision to use cemented or cementless fixation for patients undergoing TKA is typically based on the surgeon's experience and preference. However, several patient characteristics must also be taken into account. The purpose of this review was to describe the clinical outcomes of studies in which a cementless TKA system was utilized for patients who (1) were less than 60 years of age, (2) were greater than 75 years of age, (3) were obese, (4) had rheumatoid arthritis, and (5) had osteonecrosis of the knee. Based on the studies included in this review, it appears that cementless fixation is a viable option for patients who have all of the above demographics.

A Prospective Randomized Study Comparing Postoperative Pain, Biological Fixation, and Clinical Outcomes Between Two Uncemented Rotating Platform Tibial Tray Designs

BACKGROUND

With the demand for arthroplasty increasing worldwide year on year, there is a drive to improve prosthesis longevity. Biological fixation from cementless implants has been one method of trying to achieve this. We hypothesized that the addition of a hydroxyapatite (HA) coating and 4 pegs to a porous-coated tibial tray would provide a reduction in time to implant osseointegration, allowing for normal physiological stress transfer, thus improving early postoperative pain and rehabilitation as well as the elimination of radiolucent lines (RLLs).

METHODS

A prospective, randomized controlled single-blinded study was undertaken, comparing postoperative pain, radiographic evidence of biological fixation, and clinical outcomes between patients undergoing primary total knee arthroplasty with either LCS Complete POROCOAT (porous coating only) or LCS Complete DUOFIX (porous coating plus HA and pegs) knee systems (DePuy Synthes, Warsaw, IN). In total, 197 patients (205 knees) were recruited into the study between November 2006 and November 2008 and have been followed for up to 10 years.

RESULTS

There were no clinically significant differences in pain or patient-reported outcome measures when comparing the 2 designs but the tibial tray with pegs and HA showed fewer RLLs at all time points. There was no correlation between RLLs and pain and no instances of loosening or osteolysis in either group. There was 1 revision for infection in the porous coating only group.

CONCLUSION

The tray design with HA and additional fixation pegs did not confer any benefit in terms of reduced early postoperative pain or improved patient-reported outcomes, although it did result in significantly fewer RLLs. Both implants demonstrated excellent survivorship. With a cementless porous-coated tibial component, nonprogressive RLLs should be considered normal.

Spontaneous 180-Degree Rotatory Dislocation of Rotating-Platform Total Knee Arthroplasty

Rotating-bearing total knee arthroplasty has been theorized to have some advantages in the kinematics and wear characteristics of total knee arthroplasty. A rare complication of rotating-bearing total knee arthroplasty is rotary dislocation, spinout, of the polyethylene component. When these dislocations occur, they typically result in a 90-degree dislocation in respect to the axial axis of the knee. This case is unique in that it presents a complete 180-degree polyethylene dislocation without trauma.