Comparative Results From a National Joint Registry Hip Data Set of a New Cross-Linked Annealed Polyethylene vs Both Conventional Polyethylene and Ceramic Bearings

Rate of revision and wear penetration in different polyethylene liner compositions in total hip arthroplasty: a Bayesian network meta-analysis

The present Bayesian network meta-analysis compared different types of polyethylene liners in total hip arthroplasty (THA) in terms of wear penetration (mm/year) and rate of revision. The type of liners compared were the crosslinked ultra-high molecular weight polyethylene (CPE/UHMWPE), Vitamin E infused highly cross-linked polyethylene (HXLPE-VEPE), modified cross-linked polyethylene (MXLPE), highly cross-linked polyethylene (HXLPE), Cross-linked polyethylene (XLPE). This study was conducted according to the PRISMA extension statement for reporting systematic reviews incorporating network meta-analyses of healthcare interventions. In June 2024, PubMed, Scopus, Embase, Google Scholar, and Cochrane databases were accessed. A time constraint was set from January 2000. All investigations which compared two or more types of polyethylene liners for THA were accessed. Only studies that clearly stated the nature of the liner were included. Data from 60 studies (37,352 THAs) were collected. 56% of patients were women. The mean age of patients was 60.0 ± 6.6 years, the mean BMI was 27.5 ± 2.0 kg/m2. The mean length of follow-up was 81.6 ± 44.4 months. Comparability was found at baseline between groups. XLPE and HXLPE liners in THA are associated with the lowest wear penetration (mm/year) and the lowest revision rate at approximately 7 years of follow-up.

Polyethylene thickness does not influence aseptic revision rate with highly cross-linked liners in THA with 36-mm femoral heads

BACKGROUND

To reduce the risk of dislocation, larger head size can be used in total hip arthroplasty (THA). However, larger head size leads to thinner acetabular liners. With conventional polyethylene, thickness of >8 mm has been advocated to reduce stress and wear rate of the polyethylene. Modern polyethylene has become more wear-resistant. In this study, we investigated if the thickness of sequentially cross-linked polyethylene (XLPE) liners is associated with failure of THA in the medium term.

PATIENTS AND METHODS

3654 THAs were included (2009-2016), in which THA was performed with a XLPE liner in combination with a 36-mm femoral head. Patient and surgical characteristics were collected. We compared implant survival of THA with thin liners (<7.9 mm) and thick liners (⩾7.9 mm) with a Kaplan Meier survival analysis at 5 years, median follow-up and 10 years of follow-up with and point aseptic loosening and performed a multivariate analysis to estimate hazard ratios (HR).

RESULTS

Median follow-up was 7.7 years (IQR 5.6-9.8). In total, 179 revision procedures were performed, where 82 revisions (46%) were performed for aseptic loosening. The survival rate at 5 years, median and 10 years of follow-up showed no statistically significant difference in implant survival. The survival rate at 10 years follow-up was for thin liners 97.1% (95% CI, 96.3-97.9) and for thick liners 98.2% (95% CI, 97.4-99.0) in the aseptic loosening group (chi-square 2.55; p = 0.11).The adjusted HR for thick liners (⩾7.9 mm) was 0.65 (95% CI, 0.38-1.08) compared with the thin liners (<7.9 mm), which was not significantly different.

CONCLUSIONS

From this single-centre retrospective study it appears that thinner polyethylene liners are well tolerated when using second-generation highly cross-linked polyethylene. Thickness of the XLPE liners did not influence the risk of aseptic loosening of the implants in the medium term.

Long-Term Outcomes of a Titanium-Encased Ceramic Liner Total Hip Arthroplasty (15 to 21Year Results)

BACKGROUND

Historically, aseptic loosening and osteolysis were responsible for most of the revisions among young and more active patients. Ceramic-on-ceramic bearings reduced wear but presented mechanical issues such ceramic fracture or liner chipping during insertion. To prevent this from happening a titanium-encased alumina liner was developed. The aim of this study is to address long-term results of this specific ceramic design.

METHODS

All patients received an uncemented acetabular component with ceramic-on-ceramic bearing (94 hips in 77 patients). Patients were prospectively followed over 15 years. Clinical evaluation included the Harris Hip Score and Visual Analog Scale pain scale. Radiographic analysis included integration, osteolysis, and ceramic-related mechanical issues, such as malseating of the insert.

RESULTS

The studied acetabular design survivorship was 98.9% at a mean follow-up of 17.2 years. One arthroplasty was revised secondary to infection but no cup had loosened or migrated during the study. Only 1 cup showed complete radiolucent lines. There was no fracture of any ceramic component in the study group. Malseating was present in 12 acetabular components (12.8%). No osteolysis was observed with over 15 years of follow-up.

CONCLUSION

In conclusion, this acetabular component demonstrates a favorable clinical and radiological outcome with over 15 years of follow-up. Osteolysis was not observed and incomplete seating of the titanium-sleeved ceramic liner did not lead to mechanical problems.

Remaining Useful Life Prediction with Similarity Fusion of Multi-Parameter and Multi-Sample Based on the Vibration Signals of Diesel Generator Gearbox

The prediction of electrical machines’ Remaining Useful Life (RUL) can facilitate making electrical machine maintenance policies, which is important for improving their security and extending their life span. This paper proposes an RUL prediction model with similarity fusion of multi-parameter and multi-sample. Firstly, based on the time domain and frequency domain extraction of vibration signals, the performance damage indicator system of a gearbox is established to select the optimal damage indicators for RUL prediction. Low-pass filtering based on approximate entropy variance (Aev) is introduced in this process because of its stability. Secondly, this paper constructs Dynamic Time Warping Distance (DTWD) as a similarity measurement function, which belongs to the nonlinear dynamic programming algorithm. It performed better than the traditional Euclidean distance. Thirdly, based on DTWD, similarity fusion of multi-parameter and multi-sample methods is proposed here to achieve RUL prediction. Next, the performance evaluation indicator Q is adopted to evaluate the RUL prediction accuracy of different methods. Finally, the proposed method is verified by experiments, and the Multivariable Support Vector Machine (MSVM) and Principal Component Analysis (PCA) are introduced for comparative studies. The results show that the Mean Absolute Percentage Error (MAPE) of the similarity fusion of multi-parameter and multi-sample methods proposed here is below 14%, which is lower than MSVM’s and PCA’s. Additionally, the RUL prediction based on the DTWD function in multi-sample similarity fusion exhibits the best accuracy.

Comparing In Vivo Performance of Two Highly Cross-Linked Polyethylene Thermal Treatments: Remelting vs Annealing in Acetabular Liners

BACKGROUND

The introduction of highly cross-linked polyethylene (HXLPE) acetabular liners has greatly improved the wear performance of metal-on-PE bearing surfaces used in total hip arthroplasty. Changing the sterilization environment and adding thermal treatments, such as remelting or annealing, were introduced to limit on-shelf and in vivo oxidation of cross-linked liners. This study compares the wear properties of the remelted A-CLASS (MicroPort) HXLPE liner to a sequentially annealed HXLPE.

METHODS

This retrospective study assessed linear and volumetric wear rates using Martell Hip Analysis Suite, and clinical performance through incidences of revision surgeries. A total of 80 remelted and 53 annealed liners were included in the wear analysis. All hips were reviewed for revisions.

RESULTS

There were no significant differences in steady-state linear or volumetric wear rates for remelted and annealed liners, 0.01 (-0.07 to 0.14) vs -0.01 (-0.11 to 0.1) mm/y (P = .28) and -1.03 (-30.99 to 45.43) vs -1.31 (-32.23 to 23.70) mm³/y (P = .30), respectively. Both cohorts were below the 0.1 mm/y linear wear threshold. The wear rates for patients with femoral head sizes ≥36 mm were not significantly different than those with 32 and 28 mm femoral head sizes (P = .60). Similarly, wear rates for patients with an excessively vertical acetabular component (>50°) were not significantly different than those with standard acetabular component orientations (P = .97). No hips were revised due to liner-related complications.

CONCLUSION

The wear rates of the A-CLASS remelted HXLPE acetabular liner wear rates were comparable to those of a sequentially annealed HXLPE. Further long-term studies are required to ensure acceptable resistance to fatigue and in vivo oxidation.

Low failure rate at short term for 40 mm heads and second generation triple annealed HCLPE liners in hybrid hip replacements

INTRODUCTION

40 mm large diameter heads offer the advantages of lesser dislocation rates and better stability while highly cross linked polyethylene have lower wear rates than ultra high molecular weight polyethylene. Studies of the survivorship of 40 mm heads in hybrid hip replacements with Exeter stem and second generation highly cross linked polyethylene are limited. The purpose of the study is to report the short term of survivorship of the large diameter heads (40 mm) with Exeter stem with the secondary aim being the survival analysis of the thinnest second generation highly cross linked polyethylene.

METHODS

Retrospective case series of survivorship of patients with hybrid hip replacements of Exeter stems with 40 mm heads articulating with second generation triple annealed highly cross linked polyethylene liner on a uncemented acetabular shell was performed. As a subset, survival of thinnest second generation highly cross linked polyethylene survival (3.8 mm) at short term was assessed. Survival of the implants was confirmed from the hospital records and National joint registry as of 2015. Revision for any cause was taken as end point.

RESULTS

324 hybrid hip replacements with 40 mm heads had been performed for primary hip osteoarthritis. Of the 324 hip replacements, 154 hip replacements had thinnest second generation highly cross linked polyethylene (3.8 mm). Two patients had revision of components, one for periprosthetic fracture and one for deep infection. Mean age of the patients was 70.5 years (range 42-88 years, median 71, SD 8.3 years). None of the patients had revision due to trunion wear or loosening of components. The overall 5-year implant survival probability of hips with 40 mm heads was 99.4% (95% CI 98 to 100%) while the subset group of hip replacements with thinnest second generation highly cross linked polyethylene (3.8 mm) had 5-year implant survival probability of 99.3% (95% CI 97.1 to 100%).

CONCLUSION

Short term survivorship does not show significant evidence of early failure or higher rate of revision in our series of hybrid hip replacements with large diameter heads and second generation triple annealed highly cross linked polyethylene. Dislocation rate at the short term is none. Results from this series have to be carefully interpreted due to the relatively short follow up but so far results are encouraging. Long term follow up is required to conclude whether there is early or higher rate of failure. It is our intention to follow up this cohort and further publish our results at longer term.

Comparison of a highly porous titanium cup (Tritanium) and a conventional hydroxyapatite-coated porous titanium cup: A retrospective analysis of clinical and radiological outcomes in hip arthroplasty among Japanese patients

BACKGROUND

The use of 3-dimensional highly porous acetabular cups is increasing. Their structure and mechanical properties mimic those of natural bone; therefore, they should promote stronger biological fixation. In our experience with total hip arthroplasty, radiolucent lines are observed when a 3-dimensional highly porous cup (Stryker Tritanium) is used. We compared the clinical and radiographic results between a Tritanium cup and a conventional cup (Stryker Trident HA) over a short time period.

METHOD

We retrospectively compared consecutive cases of primary total hip arthroplasty using a Tritanium cup (130 cases in 118 patients) and a matched cohort using a Trident cap (130 cases in 130 patients) between January 2011 and December 2014.

RESULTS

The mean follow-up duration was 41.3 and 38.1 months (p = 0.06) for the Tritanium and Trident groups, respectively. There were significant differences between the groups for radiolucent lines, cup abduction angle, and cup-center-edge angle. There were no significant differences in the clinical results. Radiolucent lines increased in the Tritanium group (36.1% at 3 months and 60.7% at final follow-up), whereas they decreased in the Trident group (2.5% at 3 months and 0.8% at final follow-up). The occurrence of radiolucent lines was significantly higher in the Tritanium group than in the Trident group at each follow-up period. Radiolucent lines were seen in 36.1% of patients in the Tritanium group during follow-up, without initial gaps. One cup loosening in the Tritanium group was identified at the final follow-up evaluation.

CONCLUSION

Both groups showed successful clinical results over short-term follow-up; however, the Tritanium group had a significantly higher rate of radiolucent line occurrence around the cups than did the Trident group. Thus, radiolucent lines can occur when using highly porous titanium cups; these lines indicate the possibility of future cup loosening. Longer follow-up and assessment of the results of using this implant are necessary.

Acetabular reinforcement rings associated with allograft for severe acetabular defects

Acetabular revisions with severe bone defects can be challenging procedures. Several grading systems have been set into place to help the surgeon adequately gauge the degree of bone loss within the acetabulum. Internationally innovative research in orthopedics and bio-engineering has helped with progression of successful techniques and rings to re-establish the normal anatomy of the hip. The purpose of this review is to evaluate the outcomes of the different acetabular reinforcement rings in the setting of severe acetabular defects. A successive report of relevant data from the literature of multiple techniques will be provided. The procedures include the cup-cage, the Müller ring, the Ganz Ring, the Kerboull acetabular reinforcement device (KARD), the graft augmentation prosthesis (GAP) ring, and the Burch-Schneider ring. The main focus of this overview is rings only; other devices such as trabecular augments, custom-made cages, or oblong cups are not discussed. Furthermore, a special emphasis on the surgical technique of the KARD is also given. Procedures using these rings are usually associated with bone grafts either bulk or morselized. When considering the available data on these various rings used for reconstruction of the severely damaged acetabulum, the cup-cage, the KARD, and the Burch-Schneider ring appear to be reliable options for more successful long-term outcomes.

Radiolucencies surrounding acetabular components with three-dimensional coatings: artifact or real?

Background

Several 2-dimensional and 3-dimensional surfaces are available for cementless acetabular fixation. Plain radiographs are used to assess osseointegration; however, the radiographs are limited by their inability to capture the bone fixation process occurring over the 3-dimensional cup surface. In this cadaveric study, we compared the bone apposition between 2-dimensional and 3-dimensional cups.

Methods

Both types of cups were implanted in 6 cadavers and pelvic radiographs obtained. Each cup was resected from the pelvis with adequate bone around it, and subsequently embedded in a polymer. Six sections of each cup were obtained to examine the metal and bone interface. Photographs and contact radiograph images were obtained for each section, and these were graded to arrive at percent metal-bone contact values for the cups.

Results

On average, <30% of the cups' areas displayed radiolucencies on the pelvic radiographs for both cup types. For the section images and radiographs, there was about 80% aggregate contact between the cups and surrounding bone in both cup types. In the 3-dimensional cups group, some inconsistencies were found between the section photographs and the corresponding radiograph images. The radiolucencies observed on the section radiograph could not always be correlated with metal to bone gap on the section photograph.

Conclusions

Good metal-bone contact (75% + contact area) was observed on both cup types. The inconsistencies found in the 3-dimensional cup group may be because of the interaction of radiographs with the unique porous cup surface resulting in artifactual radiolucencies.

Early experience with dual mobility acetabular systems featuring highly cross-linked polyethylene liners for primary hip arthroplasty in patients under fifty five years of age: an international multi-centre preliminary study

PURPOSE

To evaluate early performance of contemporary dual mobility acetabular systems with second generation annealed highly cross-linked polyethylene for primary hip arthroplasty of patients under 55 years of age.

METHODS

A prospective observational five years study across five centers in Europe and the USA of 321 patients with a mean age of 48.1 years was performed. Patients were assessed for causes of revision, hip instability, intra-prosthetic dissociation, Harris hip score and radiological signs of osteolysis.

RESULTS

There were no dislocations and no intra-prosthetic dissociations. Kaplan Meier analysis demonstrated 97.51% survivorship for all cause revision and 99.68% survivorship for acetabular component revision at five years. Mean Harris hip score was 93.6. Two acetabular shells were revised for neck-rim implant impingement without dislocation and ten femoral stems were revised for causes unrelated to dual mobility implants.

CONCLUSION

Contemporary highly cross-linked polyethylene dual mobility systems demonstrate excellent early clinical, radiological, and survivorship results in a cohort of patients that demand high performance from their implants. It is envisaged that DM and second generation annealed HXLPE may reduce THA instability and wear, the two most common causes of THA revision in hip arthroplasty.