Impact of Acetabular Implant Design on Aseptic Failure in Total Hip Arthroplasty

Individualized megaimplants in acetabular revision arthroplasty: what have we learned in the last 15 years?

Acetabular revision arthroplasty, a demanding field of reconstructive hip surgery, calls for innovative strategies to deal with challenging bone defects and implant failure seen in revision cases. Conventional implant solutions might fall short of adequately addressing severe bone loss and ensuring stable fixation, highlighting the necessity of customized strategies. Personalized megaimplants, distinguished by their tailor-made design and large-scale construction, present a viable option to overcome these challenges. The present article provides an elaborate analysis of custom-made megaimplants in acetabular revision arthroplasty, shedding light on the underlying principles, design complexities, manufacturing methods, applications in the clinical setting, and outcome assessment. The aim of this review is to present a comprehensive insight into personalized megaimplants and their contribution to the advancement of orthopedic surgery.

The Surgical Approach Impacts Component Selection in Total Hip Arthroplasty: A Matched Cohort Study of 7,460 Hips

BACKGROUND

A higher risk of dislocation following total hip arthroplasty (THA) has been reported for the posterior approach (PA) compared to the anterior approach (AA). Dual mobility implants, larger head sizes, and elevated or face-changing liners can reduce the risk for dislocation. It remains unclear whether the component selection is influenced by the surgical approach.

METHODS

This is a retrospective study of 7,048 patients who underwent 7,460 primary THA with either AA or PA for primary hip osteoarthritis or osteonecrosis of the femoral head between 2019 and 2021. A propensity score model based on age, body mass index, height, and American Association of Anesthesiologists Score was applied. There were 2,502 AA-THA matched with 4,958 PA-THA (2,456 1:2, and 46 1:1). Groups were compared with multiple linear regression analyses/multivariate logistic regressions after controlling for American Association of Anesthesiologists Score and body mass index. In a second step, only hips operated by surgeons using both approaches were matched 1:1 (1,204 PA and AA, respectively). The same statistics were performed after controlling for "surgeon".

RESULTS

The PA was associated with a more frequent use of dual mobility implants, elevated liners, face-changing liners, as well as heads with 36 mm or larger diameters, and the implanted cups were significantly larger (P < .001, respectively). These findings were consistent for both matched cohorts.

CONCLUSION

The surgical approach impacts the component selection in THA. Patients undergoing PA-THA are more likely to receive implants with larger head size or stabilizing features compared to AA-THA.

Imaging in Hip Arthroplasty Management Part 2: Postoperative Diagnostic Imaging Strategy

Hip arthroplasty (HA) is a frequently used procedure with high success rates, but 7% to 27% of the patients complain of persistent postsurgical pain 1 to 4 years post-operation. HA complications depend on the post-operative delay, the type of material used, the patient’s characteristics, and the surgical approach. Radiographs are still the first imaging modality used for routine follow-up, in asymptomatic and painful cases. CT and MRI used to suffer from metallic artifacts but are nowadays central in HA complications diagnosis, both having their advantages and drawbacks. Additionally, there is no consensus on the optimal imaging workup for HA complication diagnosis, which may have an impact on patient management. After a brief reminder about the different types of prostheses, this article reviews their normal and pathologic appearance, according to each imaging modality, keeping in mind that few abnormalities might be present, not anyone requiring treatment, depending on the clinical scenario. A diagnostic imaging workup is also discussed, to aid the therapist in his imaging studies prescription and the radiologist in their practical aspects.

Adoption of Robotic Arm-Assisted Total Hip Arthroplasty Results in Reliable Clinical and Radiographic Outcomes at Minimum Two-Year Follow Up

INTRODUCTION

Longevity and success of total hip arthroplasty (THA) is largely dependent on component positioning. While use of robotic platforms can improve this positioning, published evidence on its clinical benefits is limited. Therefore, the aim of this study was to assess the clinical outcomes of THA with robotic surgical assistance.

MATERIALS AND METHODS

We conducted an analysis of robotic arm-assisted primary THAs performed by a single surgeon utilizing a posterior approach. A total of 99 patients (107 cases) who had a minimum two-year follow up were identified. Their mean age was 61 years (range, 33 to 84 years), and their mean body mass index was 30.5 kg/m2 (range, 18.5 to 49.1 kg/m2). There were 56% female patients and primary osteoarthritis was the principal hip diagnosis in 88.8%. Operative times, lengths of hospital stay, and discharge dispositions were recorded, along with any complications. Modified Harris Hip Scores (HHS) were calculated to quantify clinical outcomes.

RESULTS

Mean postoperative increases in HHS at 2- to 5.7-year follow up was 33 points (range, 6 to 77 points). There were no complications attributable to the use of robotic assistance. Surgical-site complications were rare; one case underwent a revision for prosthetic joint infection (0.93%) but there were no dislocations, periprosthetic fractures, or cases of mechanical implant loosening. There was no evidence of progressive radiolucencies or radiographic failure.

DISCUSSION

Robotic arm-assisted THA resulted in low complication rates at minimum two-year follow up, with clinical outcomes comparable to those reported with manual surgery.1-4 The haptically-guided acetabular bone preparation enabled reliable cementless acetabular fixation and there were no adverse events related to the use of the robot. Dislocations were avoided in this case series. Randomized controlled clinical trials are needed to compare manual to robotic surgery and to investigate whether the precision found with this functional planning will reliably reduce the incidence of dislocations.