Metal-on-Metal Hips: Ten-Year Clinical and Radiographic Outcomes of the ADEPT Metal-on-Metal Hip Resurfacing and Modular Total Hip Arthroplasty

Hip resurfacing arthroplasty reduces dislocation and infection rates without differences in clinical outcomes compared to short and standard stems: A Network Meta-Analysis

BACKGROUND

Total hip arthroplasty (THA) and hip resurfacing arthroplasty (HRA) are established treatments for hip osteoarthritis. Recent advancements have introduced short-stem THA, which offers potential advantages in terms of bone preservation and biomechanical restauration. None of previous studies compared these three surgical interventions. The aim of this network meta-analysis (NMA) is to compare HRA, short stem and standard stem in THA in terms of: (1) complications rate (global, infection and dislocation rate), (2) clinical outcomes (WOMAC, Harris Hip Score (HHS), Oxford Hip Score (OHS), Forgotten Joint Score (FJS), Postel Merle Aubigné Score (PMA) and SF-36) at short- and mid-term, (3) procedure-related variables (operative time, pain at day one and length of stay).

METHODS

A systematic literature review was conducted using multiple electronic databases (Medline, Central and Embase) to identify comparative studies evaluating at least two of the three surgical interventions. Studies were included if they reported one of our outcomes. Data synthesis was performed using a Bayesian NMA. A total of 72 studies including, 793 593 patients (mean age 54.7 years), met the inclusion criteria. The most common comparison was standard-stem THA/ HRA (94,4% of the studies).

RESULTS

The NMA did not identify differences for the rate of global complications between short stem THA/standard-stem THA (risk ratio (RR) 1.52 [95% CI 0.41-5.96]), HRA/standard-stem THA (RR 1.17 [95% CI 0.85-1.66]) and HRA/short-stem THA (RR 0.77 [95% CI 0.20-2.95]). Regarding infection and dislocation, standard THA had a higher rate of infection (risk ratio 2.14 [95% CI 1.33-5.44]) and of dislocation (risk ratio 13.45 [95% CI 3.37-98.21]) compared to HRA. For functional outcomes at short term, no differences were observed between HRA and standard-stem THA for WOMAC (Mean Difference (MD) -0.01 [95% CI -0.51 to 0.40]), HHS (MD 0.05 [95% CI -3.26 to 3.45]), PMA (MD -0.13 [95% CI -0.94 to 0.71]) and FJS (MD -1.64 [95% CI -9.04-5.45]). For functional outcomes at mid-term, no differences were observed between HRA and standard-stem THA for WOMAC (MD -0.07 [95% CI -1.13 to 1.05]), HHS (MD -0.02 [95% CI -1.55 to 1.36]), PMA (MD -0.03 [95% CI -0.60 to 0.49]) and SF-36 (MD 0.11 [95% CI -3.37 to 3.61]). No difference was observed for comparison of short-stem THA/standard-stem THA and HRA/short-stem THA for clinical outcomes.The surgical time was shorter for HRA compared to short-stem THA (MD-34.05 [95% CI -53.25 to -13.28]) and standard-stem THA (MD -16.25 [95% CI -24.84 to -7.53]). No difference was observed between HRA and standard-stem THA for VAS at day one (MD 0.22 [95% CI -1.90 to 2.13]) and for the length of stay (MD 0.48 [95% CI -0.27 to 1.34]).

CONCLUSION

HRA demonstrated had lower infection and dislocation rate compared to standard THA. HRA also offers a shorter operative time. However, no difference was observed for functional outcome between the three technics. These findings support the notion that the choice of technique should be tailored to patient-specific characteristics, highlighting the potential shift towards personalized hip arthroplasty.

LEVEL OF EVIDENCE

III; Network meta-analysis.

Metallosis, Trunnionosis, and Head-stem Dissociation of the Exeter v40 Stem in a Metal-on-Metal Hip: A Unique Case

Introduction

In this article, we report a unique case of head-stem dissociation in a metal-on-metal total hip replacement which utilized an Exeter stem. Although metallosis and pseudotumor formation are well recognized complications of metal-on-metal hip replacements, head-stem dissociations are rare with few being reported in literature. To the best of our knowledge, this case report is the first to report this occurrence in an Exeter stem.

Case Report

A 76-year-old male presented to the emergency department with pain and discomfort in his left hip triggered by a twisting movement while getting into bed. The patient described a "pop" in his hip upon turning and reported mild ongoing discomfort in his left hip for the past 4 weeks before this acute presentation. X-rays and Metal artifact reduction sequence magnetic resonance image (MARS) revealed head-stem dissociation along with pseudotumor formation. The patient successfully underwent a two stage revision with no perioperative complications.

Conclusion

This case report, to the best of our knowledge, is the first to report catastrophic failure of a metal-on-metal hip caused by trunnionosis and subsequent head-stem dissociation. We report successful management of this unique case and hope to highlight the complexities and challenges associated with metal-on-metal THR. This case report is aimed at raising clinical awareness of this rare complication which requires expert management for a successful outcome.

Metal-on-metal hip resurfacing arthroplasty: is it safe and reliable? A synopsis of the past, the present, and the future of HRA

This paper discusses the existing literature in the field of metal-on-metal (MoM) hip resurfacing arthroplasty (HRA), the background (why was it developed), the past (what was the evidence leading to its rise and fall in clinical use), the present situation (why a potential resurgence), and the future directions for potential improvements. All literature relevant to MoM HRA was reviewed and summarized to provide a comprehensive summary. Furthermore, a detailed literature search was performed on PubMeD, MEDLINE, and Google Scholar to identify all clinical studies reporting a minimum 10 years of outcomes for modern MoM HRA devices from February 2018 to February 2023. In addition, joint registry data over the same time period, available in the public domain, was examined to extract related information on MoM HRA. Metal ions are present in almost all types of hip replacement; on the whole, however, the risk of revision for resurfacing due to metal-related pathologies is very low, but higher than in other types of bearings. There are studies that show that some brands of MoM resurfacing prostheses have achieved excellent clinical outcomes in long-term follow-up studies and are still in use although less commonly than in early 2000s. Use of alternative bearing surfaces has demonstrated excellent results in the short-term and a very critical long-term follow-up of these cases still will help establish their place in the hip arthroplasty world. HRA deserves a permanent place in the armamentarium of orthopedic surgeons and in the hand of experienced surgeons.

Towards the First Generation of Biomimetic Fixation for Resurfacing Arthroplasty Endoprostheses

This paper presents advances in designs of resurfacing arthroplasty endoprostheses that occurred through their historical generations. The critical characteristics of contemporary generation hip resurfacing arthroplasty endoprostheses are given and the failures resulting from the specific generation cemented and short stem fixation of the femoral component are reviewed. On the background of these failures, the critical need arises for an alternative approach to the fixation of components of resurfacing arthroplasty leading towards the first generation of biomimetic fixation for resurfacing arthroplasty endoprostheses. The state of the art of the completed bioengineering research on the first biomimetic fixation for resurfacing arthroplasty endoprostheses is presented. This new design type of completely cementless and stemless resurfacing arthroplasty endoprostheses of the hip joint (and other joints), where endoprosthesis components are embedded in the surrounding bone via the prototype biomimetic multi-spiked connecting scaffold (MSC-Scaffold), initiates the first at all generations of biomimetic endoprostheses of diarthrodial joints.