Personalized Hip Joint Replacement with Large Diameter Head: Current Concepts

Excellent Results of Large-Diameter Ceramic-On-Ceramic Bearings in Total Hip Arthroplasty at Minimum Ten-Year Follow-Up

BACKGROUND

This study reports the minimum 10 years results of total hip arthroplasty (THA) performed using a monoblock acetabular component with a large-diameter head ceramic-on-ceramic bearing.

METHODS

Of the 276 THAs included in this study, there were eleven deaths and 27 patients lost to follow up (11%) during the follow-up, leaving 237 (85%) hips available for review at a mean of 10.5 years (range, 10 to 12) postoperatively. Reoperations, implant revisions, adverse events, clinical outcomes, radiographic evaluation, and whole blood metal ion levels were assessed at the last follow-up.

RESULTS

After a minimum of 10 years, implant survivorship was 98.7%. There were 3 revisions (1.3%): one for insufficient acetabular cup primary fixation, one traumatic periprosthetic acetabular fracture, and one probable deep chronic infection. No dislocation or ceramic implant fracture was observed. The mean University of California at Los Angeles activity score, Western Ontario and McMaster Universities Osteoarthritis Index score, and Forgotten Joint Score were 5.6 (2 to 10), 90.1 (9 to 100), and 79.2 (4 to 100), respectively. All patients (100%) were satisfied or very satisfied. Since implantation, 43% of patients reported hearing a squeaking noise from the prosthesis. But all patients who reported squeaking were satisfied with the surgery. The mean titanium level was 2.2 μg/L (1.1 to 5.6). No progressive radiolucent lines, osteolysis, or implant loosening signs were observed at the last radiographic evaluation.

CONCLUSIONS

A large-diameter head ceramic-on-ceramic THA provides outstanding long-term (minimum 10 years) implant survivorship with unrestricted activity while avoiding implant impingement, liner fracture, and hip instability. Functional outcomes, satisfaction, and joint perception were excellent. Although the incidence of squeaking was high, it did not affect patient satisfaction or function. The systemic titanium levels were low, related to unavoidable passive corrosion of implant surfaces, and did not reveal any indirect signs of trunnionosis.

Head size in Delta ceramic-on-ceramic total hip arthroplasty: a comparative registry study

INTRODUCTION

Optimal bearing size in total hip arthroplasty (THA) has not been clearly ascertained, but large diameter ceramic balls may improve function and implant stability, with minimal concerns for wear. Delta ceramic-on-ceramic (COC) THA were stratified based on head diameter (32, 36 and 40 mm), aiming to assess: 1) survival rates, reasons for revision and hazard ratios for failure; 2) survival rates and hazard ratios for aseptic loosening, dislocation/primary instability, liner failure.

MATERIALS AND METHODS

A regional arthroplasty registry was enquired about Delta COC THA performed for primary osteoarthritis, stratified by head size. 13,161 primary cementless THAs were included in the study, with a mean follow-up of 5.7 years (range: 0-17): 3980 (30.2%) 32 mm balls, 8327 (63.3%) 36 mm heads, 854 (6.5%) 40 mm heads.

RESULTS

The three cohorts achieved similar survival rates (p = 0.99) and adjusted hazard ratios (p > 0.05). No revisions for head breakage or metallosis occurred. When revision for cup aseptic loosening was the endpoint, the survival rates of three cohorts (p = 0.08) and the adjusted hazard ratios (p > 0.05) were similar. The three cohorts achieved comparable survival rates when revision for dislocation/primary instability was the endpoint (p = 0.08). When the endpoint was revision for liner breakage, 32 mm cohort showed higher rates of revision (p = 0.01). No liner failure was detected in the 40 mm cohort.

CONCLUSIONS

32 mm, 36 mm and 40 mm provided similar 10-year survival rates in Delta COC THA. 40 mm heads emerged as safe options but did not lower the revisions for dislocations/primary instability.

LEVEL OF EVIDENCE

IV (therapeutic study).

Techniques and Technologies for the Intraoperative Assessment of Component Positioning, Leg Lengths, and Offset in Total Hip Arthroplasty: A Systematic Review

Background

Many techniques and technologies exist for the intraoperative assessment of component positioning, leg lengths, and offset in total hip arthroplasty, but with limited comparative data. We conducted a systematic review of the available literature to evaluate the range of techniques and technologies for the intraoperative assessment of component position as well as leg lengths and offset in terms of accuracy, precision, surgical time, cost, and relationship to clinical outcomes.

Methods

A comprehensive search of the Embase and Medline databases from 1974 to 2023 was performed. We included controlled or comparative prospective clinical studies. Cochrane's risk-of-bias tool for randomized trials and Risk of Bias in Non-Randomized Studies - of Interventions tools were used by 2 independent reviewers to evaluate each study for risk of bias. We conducted both qualitative and quantitative analyses of the studies included. However, a meta-analysis was deemed not to be feasible due to heterogeneity.

Results

Our review included 25 studies with 52 intraoperative techniques and technologies. Mechanical guides and computerized navigation were most frequently evaluated in the included studies. Computerized navigation systems consistently showed the greatest accuracy and precision across all measures, at the cost of longer mean operative time. In contrast, freehand techniques demonstrated the poorest accuracy and precision. Insufficient data were found to reach any meaningful conclusions in terms of differences in overall surgical cost or clinical outcomes.

Conclusions

Evidence shows that computerized navigation systems are most accurate and precise in positioning components during total hip arthroplasty. Further research is needed to determine their health and economic impact and whether the accuracy and precision of navigated techniques are justified in terms of clinical outcomes.

Pelvic flexion/extension and its impact on functional acetabular alignment and stability following total hip replacement

PURPOSE

Dislocation following total hip arthroplasty (THA) remains a significant clinical problem and can occur even with optimal implant alignment. We hypothesized that different patterns of pelvic flexion/extension (PFE) during daily activities may influence acetabular alignment and contribute to impingement and instability following THA. Recently, there has been an increased interest in spinopelvic alignment and its impact on THA. Therefore, this study aimed to identify different patterns of PFE that could be predictive of instability following THA.

METHODS

A range of motion (ROM) simulator was used to demonstrate the effects of different patterns of PFE on ROM and impingement. The findings were applied to PFE measurements obtained from 84 patients in standing and sitting positions.

RESULTS

Three different categories of PFE were identified: normal, hypermobile, and stiff. ROM simulator revealed that changes in PFE had affected ROM and impingement significantly. Patients in the stiff pelvis category, even with "optimal" implant alignment, were more susceptible to implant impingement.

CONCLUSIONS

The different patterns of PFE during daily activities could affect acetabular alignment and stability following THA. We propose a classification system that can identify different types of PFE and predict their effects on the stability of prostheses following THA. Hence, we believe that patients with unfavorable PFE may require modified cup alignment.

A rare case of liner dissociation with ceramic-on-ceramic preassembled acetabular components: a case report

Liner dissociations are rare but catastrophic complications after THA, requiring revision surgery. Although this complication has been well documented in THA with modular components, it has been rarely described in preassembled designs. In this report we present a rare case of liner dissociation in a ceramic-on-ceramic pre-assembled cup design. A 41-year-old man who received THA seven years ago, presented with sudden pain in the hip. Radiographic examination confirmed a small dissociation of the liner component in the acetabular shell, as well as radiolucency between the acetabular shell and the ceramic liner, and pneumarthrosis. Revision surgery was carried out six weeks following the liner dissociation. To make an accurate diagnosis, orthopaedic surgeons must be aware of the symptoms of liner dissociation.

Observations on the Present and the Future of Hip Surgery

Each period in history has its own peculiar fashions and trends, and contemporary research on hip surgery is no exception [...].

Advances in Hip Replacement Surgery

Total hip arthroplasty (THA) is one of the most successful types of surgical operation, with some considering it "the operation of the century" [...].

Evolution of Concepts: Can Personalized Hip Arthroplasty Improve Joint Stability?

Hip arthroplasty procedures are successful and reproducible. However, within the first two post-operative years, hip dislocations are the most common cause for revisions. This is despite the majority of the dislocations having the acetabular component within what is described as the 'safe zone'. The limitations of such boundaries do not take into account the variability of individual hip anatomy and functional pelvic orientation that exist. An alternative concept to address hip instability and improve overall outcomes is functional acetabular orientation. In this review article, we discuss the evolution of concepts, particularly the kinematic alignment technique for hip arthroplasty and the use of large-diameter heads to understand why total hip arthroplasty dislocations occur and how to prevent them.

Evaluating the Mechanical and Tribological Properties of 3D Printed Polylactic-Acid (PLA) Green-Composite for Artificial Implant: Hip Joint Case Study

Artificial implants are very essential for the disabled as they are utilized for bone and joint function in orthopedics. However, materials used in such implants suffer from restricted mechanical and tribological properties besides the difficulty of using such materials with complex structures. The current study works on developing a new polymer green composite that can be used for artificial implants and allow design flexibility through its usage with 3D printing technology. Therefore, a natural filler extracted from corn cob (CC) was prepared, mixed homogeneously with the Polylactic-acid (PLA), and passed through a complete process to produce a green composite filament suit 3D printer. The corn cob particles were incorporated with PLA with different weight fractions zero, 5%, 10%, 15%, and 20%. The physical, mechanical, and tribological properties of the PLA-CC composites were evaluated. 3D finite element models were constructed to evaluate the PLA-CC composites performance on a real condition implant, hip joints, and through the frictional process. Incorporating corn cob inside PLA revealed an enhancement in the hardness (10%), stiffness (6%), compression ultimate strength (12%), and wear resistance (150%) of the proposed PLA-CC composite. The finite element results of both models proved an enhancement in the load-carrying capacity of the composite. The finite element results came in line with the experimental results.

Degree of Pelvic Rotation in the Coronal Plane on Postoperative Radiographs Obtained after Total Hip Arthroplasty

There are many published cup anteversion measurements for postoperative total hip arthroplasty (THA), including Liaw’s, Lewinnek’s, and Murray’s methods. However, most measurements ignore the potential pelvic rotation on radiographs except in Liaw’s method. Without considering pelvic rotation, clinicians can miscalculate cup anteversion. Therefore, we aimed to quantify the mean degree of pelvic rotation. Herein, we collected 388 radiographs of 98 postoperative THA hips of 77 patients and measured pelvic rotation by measuring h, the horizontal displacement of the sacrococcygeal junction associated with the upper pole of the symphysis pubis, and ssd, the distance between the sacrococcygeal junction and pubic symphysis. The angle θ of pelvic rotation was defined as θ = arc sin (h/ssd) × (180°/π). The mean degree of pelvic rotation was then calculated. The standard deviation of h was 7.84 mm, and the mean ssd was 158 mm. The potential pelvic rotation was 2.50°. The p-values from the paired t-test were all >0.05 when interobserver and intraobserver errors were assessed. This is the first study to quantify the potential pelvic rotation in the coronal plane on postoperative plain radiographs. The potential pelvic rotation was too large to be neglected during the measurement of cup anteversion.

Computational Contact Pressure Prediction of CoCrMo, SS 316L and Ti6Al4V Femoral Head against UHMWPE Acetabular Cup under Gait Cycle

Due to various concerns about the use of metal-on-metal that is detrimental to users, the use of metal as acetabular cup material was later changed to ultra high molecular weight polyethylene (UHMWPE). However, the wear on UHMWPE releases polyethylene wear particles, which can trigger a negative body response and contribute to osteolysis. For reducing the wear of polyethylene, one of the efforts is to investigate the selection of metal materials. Cobalt chromium molybdenum (CoCrMo), stainless steel 316L (SS 316L), and titanium alloy (Ti6Al4V) are the frequently employed materials. The computational evaluation of contact pressure was carried out using a two-dimensional axisymmetric model for UHMWPE acetabular cup paired with metal femoral head under gait cycle in this study. The results show Ti6Al4V-on-UHMWPE is able to reduce cumulative contact pressure compared to SS 316L-on-UHMWPE and CoCrMo-on-UHMWPE. Compared to Ti6Al4V-on-UHMWPE at peak loading, the difference in cumulative contact pressure to respective maximum contact pressure is 9.740% for SS 316L-on-UHMWPE and 11.038% for CoCrMo-on-UHMWPE.