Component positioning and ceramic damage in cementless ceramic-on-ceramic total hip arthroplasty

Total Hip Arthroplasty for Low-Grade Developmental Hip Dysplasia Changes the Ipsilateral Knee Alignment on the Axial and Coronal Planes

BACKGROUND

There is a paucity of data regarding the post-operative influence of total hip arthroplasty (THA) on the axial and coronal alignments of the ipsilateral knee. A CT study was designed to assess the post-THA changes in axial and coronal knee alignments in low-grade dysplastic hips.

METHODS

Forty Crowe I-II dysplastic hips in 37 patients were assessed: a pre-operative CT scan from the fourth lumbar vertebra to the tibial plateaus was compared to a similar post-operative CT scan performed after a minimum of 2 years after THA.

RESULTS

THA implantation caused significant post-operative changes in terms of the rotation height (2 mm lowering; p = 0.003); center of rotation medialization (10 mm medialization; p < 0.001); femoral offset (11 mm increase; p < 0.001); femoral antetorsion (22° internal rotation; p < 0.001), and hip internal rotation (9° internal rotation; p < 0.001). The femoral axis angle deviated in the valgus (5.5° ± 1.1°, p < 0.001) and the mechanical lateral distal femoral angle deviated in the varus (86° ± 2.7°, p = 0.001). The pelvic-tibial alignment changed from 88.2° ± 11.7° to 96° ± 9.3° (p < 0.001). Patellar alignment was not influenced.

CONCLUSIONS

In conclusion, THA imposes significant changes in low-grade dysplastic hips: all the modifications tend to neutralize the coronal alignment and, mostly, the rotational alignment, without substantial and durable variations of the patellofemoral joint. Large clinical trials should confirm whether radiological changes impact anterior knee pain and patellar stability.

Ceramic-related noise as an adverse outcome in total hip arthroplasty

Introduction Ceramic hip replacement bearings have shown to be low wearing and biocompatible. The last two generations of Biolox Forte and Biolox Delta ceramics have have established themselves as durable bearings. However, squeaking and noise from ceramic bearing THRs is well recognised in the 21st century.

The objective was to explore the problem of noise in the ceramic bearing of THA based on the analysis of the foreign and Russian literature.

Material and methods In presented the analysis of Foreign and Russian literature searches for the review were produced according to PRISMA recommendations using PubMed, Scopus, Google Scholar, eLibrary. MINOR was used to assess the methodological quality of articles.

Results and Discussion Noise in ceramics is observed in 37.7 %. There are many theories on the origin and mechanism of noise including liner impingement and loading, film disruption, third body, microseparation and resonance. However, there is still no consensus on what is noise in the ceramic bearing and how to solve this problem.

Conclusion Literature review of ceramic bearing indicated enough unanswered questions. The noise may play a role as a predictor of improper use of endoprosthesis with accumulated database resulting in better understanding of the phenomenon, methods of the correction and timely prevention of ceramic breakage.

Cup Overhanging in Anatomic Socket Position or High Hip Center of Rotation in Total Hip Arthroplasty for Crowe III and IV Dysplasia: A CT-Based Simulation

Cup overhanging in total hip arthroplasty is a predisposing factor to iliopsoas impingement. In dysplastic hips, cup implantation was simulated in an anatomic hip center of rotation (AHCR) and in high hip center (HHCR). We sought to assess: (1) the percentage of prominent cups; (2) quantify the cup protrusion at different sites on frontal, axial and sagittal views. In 40 Crowe III-IV hips, using a 3D CT-based planning software, cup planning in AHCR and HHCR (CR height ≥ 20 mm) was performed for every hip. Cup prominence was assessed on every plane. HHCR cups were less anteverted (p < 0.01), less medialized (p < 0.001) and less caudal (p = 0.01) than AHCR sockets. AHCR cups were more frequently prominent on at least one plane (92.5% vs. 77.5%), with minimal agreement between the two configurations (k = 0.31, p = 0.07). AHCR cups protruded more than HHCR sockets in the sagittal (p = 0.02) and axial planes (p < 0.001). Axially, at the center of the cup, prominence 6−11 mm occurred in nine (22.5%) AHCR and one (2.5%) HHCR socket. In conclusion, while a routine high hip center should not be recommended, cup placement at a center of rotation height < 20 mm is associated with higher rates and magnitudes of anterior cup protrusion in severe dysplasia.

Analytical review on the biocompatibility of surface-treated Ti-alloys for joint replacement applications

INTRODUCTION

With the advancement of joint replacements such as total hip replacement (THR), Titanium (Ti) and its alloys are widely used as implant materials. The bearing surface of Ti improves the longevity of implants. In this perception, researchers design a Ti-alloy that increases the wear and corrosion resistance to enhance osteogenesis and mechanical stability.

AREAS COVERED

: This paper is dedicated to finding the major causes of the failure of THR. Further, this paper provides an overview of the application of metallic alloys and their influencing factors that influence biocompatibility. The most contributing part of this paper focuses on the post-treatment impact on Ti-alloys biocompatibility.

EXPERT OPINION

This paper revealed and discussed that Ti alloys' biocompatibility for orthopedic applications mainly depends on antibacterial activities that decide tissue-implant compatibility. Therefore, performing surface treatment enhances the biocompatibility of Ti alloys. It was also observed that more water contact angle (WCA) induces bacterial growth and enhances cell adhesion. In contrast, the treated surface increases the antibacterial activities at lower WCA. Surface heat treatment with sintering or micro-arc oxidation achieves suitable antibacterial or antimicrobial activities.

Which stem in total hip arthroplasty for developmental hip dysplasia? A comparative study using a 3D CT-based software for pre-operative surgical planning

BACKGROUND

Stem choice in total hip arthroplasty (THA) for hip dysplasia is still controversial. The aims of the study were to evaluate (1) which stem design provided the highest percentage of adequate reconstructions in THA for dysplasia and (2) any correlation between the reconstructions provided by the stems and the native femoral morphology.

MATERIALS AND METHODS

150 CT scans including 200 adult dysplastic hips were randomly selected. Using the 3D CT-based software Hip-Op for surgical planning, the native hip anatomy was studied. Then, a single wedge tapered stem, an anatomical stem and a conical tapered stem were simulated in every hip. An adequate reconstruction of hip biomechanics was obtained when combined anteversion, offset restoration, coronal and sagittal tilt, canal filling and leg lengthening were inside the normal ranges.

RESULTS

Conical stems achieved the highest percentage of adequate reconstructions (87%, p < 0.0001). The anatomical stem was the worst performer. Single wedge and anatomical stem acceptability was mainly influenced by the combined anteversion. Stem anteversion was correlated with the femoral anteversion (fair correlation), the calcar femorale (fair) and the mediolateral femoral diameter at isthmus (poor). When the femoral anteversion was ≥ 25°, combined anteversion was very acceptable for the conical stem (99.2%), whereas the rate of acceptable combined anteversion for the single wedge tapered stem was 71.4%, and that for the anatomical stem was 51.6% (p < 0.0001).

CONCLUSIONS

Stem choice in developmental hip dysplasia is mainly driven by appropriate combined anteversion, which is dependent on the coronal and axial femoral morphologies. As a rule of thumb, tapered stems are adequate when femoral anteversion is < 25°; conical stems should be adopted for higher anteversions.

LEVEL OF EVIDENCE

IV.

Measuring stem anteversion after total hip arthroplasty: posterior condylar tangent versus transepicondylar axis

OBJECTIVE

Stem anteversion in total hip arthroplasty (THA) has been measured using two different distal references, the posterior condyle (PC) or the transepicondylar axis (TEA). The reliability, the difference in value between these two techniques, and the possible confounding factors are scarcely known. Aims of this work were to assess (1) the intraclass correlation and the difference between the two measurement techniques and (2) the possible influence of condylar dysmorphisms on the anteversion value discrepancy.

MATERIALS AND METHODS

A consecutive series of post-THA CT scans were selected, excluding hip dysplasia, end-stage knee osteoarthritis, and replaced knees. Using a surgical planning software, stem anteversion was measured using the PC or the TEA reference. The intraclass reliability was assessed. The anteroposterior femoral condyle diameters were measured: the difference and the ratio were measured and correlated with the stem anteversion values.

RESULTS

91 CT scans were included. Inter/intra-observer TEA measurements were more reliable than PC. The intraclass correlation between PC and TEA anteversion measurements was good, 0.954 (CI 95% 0.922-0965). The mean difference between PC and TEA anteversion was 5.27 ± 2.41°. The difference and the ratio between the two anteroposterior condyle diameters did not influence the anteversion difference (respectively, p 0.797 and p 0.901).

CONCLUSIONS

TEA and PC demonstrated to achieve a good correlation, not dependent from the condyle morphology. However, the difference between the two measurements (5°) can severely influence the combined anteversion (10-20%): due to clinical applicability and better inter/intra-observer agreement, TEA should be preferred for measuring stem anteversion.

lsolated acetabular revisions of articular surface replacement (ASR) XL implants with highly porous titanium cups and Delta bearings

INTRODUCTION

Articular surface replacement (ASR) XL implants exhibit higher-than-expected revision rates, blood ion concentrations and soft tissue lesions, making revisions troublesome and potentially unsatisfying. Appropriate techniques and outcomes in ASR XL revisions are rarely documented. The aims of this study were the assessments of pre-revision data, post-revision clinical and radiographic outcomes and ion levels in isolated acetabular ASR XL revisions performed using highly porous titanium cups and Delta ceramic articulations.

METHODS

18 isolated acetabular ASR XL revisions in 16 patients were performed using Ti-Por cups (Adler Ortho, Milan, Italy) and Delta bearings (CeramTec, Plochingen, Germany). Pre-revision demographic, clinical, radiological and implant-related features were assessed. Clinical and radiographic parameters (cup positioning, osseointegration) after revisions were evaluated at a minimum follow-up of 5 years. Ion concentrations in blood and urine were collected in pre-revision setting and 1 year after revision.

RESULTS

4 complications occurred in 3 different revisions (16.7%), 1 dislocation, 2 infections, 1 psoas impingement. No re-revision was performed at 5 years (1 scheduled arthroscopy). Good clinical outcomes were achieved (HHS score: 88.3 ± 9.2). All the cups showed reassuring signs of osseointegration (>3 parameters). Blood ion concentrations significantly decreased: patients with Co blood ion concentration over the threshold (7 μg/l) decreased from 76.5% to 0%. No pre-revision or intraoperative data influenced the revision outcomes.

CONCLUSIONS

Highly porous titanium cups and Delta ceramic articulations provided reliable mid-term clinical and radiographic outcomes in isolated acetabular ASR XL revisions. Ion concentrations significantly decreased. Multicentre prospective controlled studies are required to confirm these preliminary outcomes.