The Effect of Surgical Approach and Femoral Prosthesis Type on Revision Rates Following Total Hip Arthroplasty: An Analysis of the Most Commonly Utilized Cementless Stems

Outcomes of 1,021 consecutive cases utilizing a triple tapered collared stem and automated broaching system

Background: For total hip arthroplasty (THA), a number of different femoral stem designs exist, each offering potential benefits and risks to patients. Preparation and implantation of the femoral component may be performed with manual instrumentation or with automated broaching systems. The combination of stem and femoral preparation choice may influence patient outcomes. The purpose of this study was to report on a large consecutive series of a collared, triple tapered, cementless stem broached and impacted with an automated system through a mini-posterior approach. Methods: 1021 consecutive THAs with a cementless triple-tapered fully coated titanium femoral stem performed by a single surgeon via a minimally invasive posterior approach all utilizing automated broaching (AB) were collected retrospectively. Patient demographic data, proximal femoral anatomical features, radiographic outcomes (e.g., subsidence), PROMIS scores, and intra-operative and postoperative complications were collected and analyzed. Results: 7/1021 (0.68%) intra-operative calcar fractures and 11/1021 (1.08%) postoperative periprosthetic femoral fractures were observed. The average postoperative subsidence was 0.5 mm. Subsidence was not associated with age, BMI, or proximal femoral anatomy (Dorr C). There were no revisions for postoperative mechanical loosening or instability. No increase in periprosthetic fracture was noted amongst the first 100 cases using AB (0/100) when compared to the subsequent 100 (0/100). All patients experienced statistically significant improvement in PROMIS scores postoperatively at 1-year follow-up. Conclusion: This large, consecutive, single surgeon series demonstrates excellent results of the aforementioned stem prepared and impacted with AB. At mid-term follow-up, there were no revisions for mechanical loosening and all-cause survivorship was 98.2%.

Correlation of cross-linking as measured by the trans-vinylene index and in vitro wear of polyethylene from various acetabular liner brands

Aims

Highly cross-linked polyethylene (HXLPE) greatly reduces wear in total hip arthroplasty, compared to conventional polyethylene (CPE). Cross-linking is commonly achieved by irradiation. This study aimed to compare the degree of cross-linking and in vitro wear rates across a cohort of retrieved and unused polyethylene cups/liners from various brands.

Methods

Polyethylene acetabular cups/liners were collected at one centre from 1 April 2021 to 30 April 2022. The trans-vinylene index (TVI) and oxidation index (OI) were determined by Fourier-transform infrared spectrometry. Wear was measured using a pin-on-disk test.

Results

A total of 47 specimens from ten brands were included. The TVI was independent of time in vivo. A linear correlation (R2 = 0.995) was observed between the old and current TVI standards, except for vitamin E-containing polyethylene. The absorbed irradiation dose calculated from the TVI corresponded to product specifications for all but two products. For one electron beam-irradiated HXLPE, a mean dose of 241% (SD 18%) of specifications was determined. For another, gamma-irradiated HXLPE, a mean 41% (SD 13%) of specifications was determined. Lower wear was observed for higher TVI.

Conclusion

The TVI is a reliable measure of the absorbed irradiation dose and does not alter over time in vivo. The products of various brands differ by manufacturing details and consequently cross-linking characteristics. Absorption and penetration of electron radiation and gamma radiation differ, potentially leading to higher degrees of cross-linking for electron radiation. There is a non-linear, inverse correlation between TVI and in vitro wear. The wear resistance of the HXLPE with low TVI was reduced and more comparable to CPE.

No Difference in Revision Rates or Patient-Reported Outcome Measures Between Surgical Approaches for Total Hip Arthroplasty Performed for Femoral Neck Fracture: An Analysis of 5,025 Primary Total Hip Arthroplasties From the New Zealand Joint Registry

BACKGROUND

Total hip arthroplasty (THA) for femoral neck fracture (FNF) can be performed through different surgical approaches. This study compared the revision rates and patient-reported outcome measures by surgical approach.

METHODS

Data from the New Zealand Joint Registry were analyzed for patients undergoing primary THA for FNF from January 2000 to December 2021. A total of 5,025 THAs were performed for FNF; the lateral approach was used in 2,499 (49.7%), the posterior in 2,255 (44.9%), and the anterior in 271 (4.3%). The primary outcome measure was the all-cause revision rate. Secondary outcome measures included revision rates for: dislocation, aseptic femoral component loosening, periprosthetic fracture, and infection. Oxford Hip Scores (OHS) were also collected. Age, sex, body mass index, American Society of Anesthesiologists score, femoral head size, dual mobility use, femoral fixation, and surgeon experience were assessed as potential confounding variables.

RESULTS

There was no difference in the revision rates between lateral and posterior (P = .156), lateral and anterior (P = .680), or posterior and anterior (P = .714) approaches. There was no difference in the reasons for revision between the lateral and posterior approaches or 6-month OHS (P = .712). There was insufficient data to compare the anterior approach.

CONCLUSIONS

There is no difference in the overall revision rates, reasons for revision, or OHS between the lateral and posterior surgical approaches for THA performed for FNF. Insufficient data on the anterior approach is available for an accurate comparison.

LEVEL OF EVIDENCE

Level III.

Is there any clinical advantage of capsular repair over capsular resection for total hip arthroplasty? An updated systematic review and meta-analysis

INTRODUCTION

Although several surgical approaches, with or without capsular repair, can be used during total hip arthroplasty (THA), there is no clear evidence that capsular repair provides a clinical advantage post-surgery, regardless of surgical approach. This systematic review and meta-analysis evaluated whether capsular repair using various surgical approaches provides a clinical advantage over capsular resection post-THA.

METHODS

This study was conducted in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) 2020 checklist for systematic reviews and meta-analyses. Multiple comprehensive literature searches were performed. Results were summarized qualitatively as meta-analysis of pooled odds ratios, and the standardized mean difference, with 95% confidence intervals for each group: capsular repair or capsular resection. A P value < 0.05 was considered statistically significant. Each study was evaluated for the risk of bias. Publication bias was also assessed.

RESULTS

A total of 12 studies were included after screening and eligibility assessment. The odds ratio for hip dislocation after capsular repair was 0.14 (P < 0.00001). The standard mean difference of the Harris Hip Score (HHS) after capsular repair was 1.11 (P = 0.02). There were no significant differences between groups with respect to operation time (P = 0.79) and blood loss (P = 0.42).

CONCLUSION

The current meta-analysis suggests that capsular repair leads to lower dislocation rates and a better HHS after THA.

The influence of stem alignment on the bone mineral density around the Polarstem following total hip arthroplasty

INTRODUCTION

Bone mineral density is important in detecting implant loosening after total hip arthroplasty. The Polarstem can improve postoperative bone mineral density changes, but no information exists on the influence of postoperative stem alignment. Therefore, we investigated the relationship between bone mineral density change and stem alignment following total hip arthroplasty using a cementless Polarstem.

MATERIALS AND METHODS

This retrospective study included 42 patients (50 hips) who underwent total hip arthroplasty using a cementless Polarstem. Bone mineral density around the stem was measured according to the established Gruen zone classification using dual-energy X-ray absorptiometry. Measurements were performed 2 months postoperatively (baseline) and 6, 12, 18, and 24 months postoperatively. Bone mineral density changes at each follow-up were calculated as (bone mineral density at follow-up/at 2 weeks) × 100 (%). The stem varus, anterior tilt, and anteversion angles were measured using computed tomography. The correlation coefficient between bone mineral density changes and stem alignment were investigated.

RESULTS

The 24-month postoperative bone mineral density increased in zones 4 (106.0%) and 5 (107.3%) and decreased in zones 1 (89.6%) and 7 (90.6%). The mean stem varus angle, anterior tilt, and anteversion error were - 0.3° ± 1.8°, 1.9° ± 2.2°, and 6.8° ± 5.4°. Negative correlations were observed between the stem varus angle and 24-month postoperative bone mineral density change in zone 1 (r = - 0.34, p = 0.02), and the stem anteversion error and 24-month postoperative bone mineral density change in zone 1 (r = - 0.48, p < 0.01) and zone 7 (r = - 0.31, p = 0.03).

CONCLUSIONS

The cementless Polarstem may have a positive effect on postoperative bone mineral density in the distal femur. However, varus malalignment and anteversion error of the stem could have a negative influence on the bone mineral density changes in the proximal femur.

How to Prevent Aseptic Loosening in Cementless Arthroplasty: A Review

Aseptic loosening is the main late postoperative complication of cementless total hip arthroplasties (THAs), leading to pain and functional impairment. This article aims to update the orthopedic surgeon on the various methods by which the aseptic loosening rate can be reduced. We performed a systematic review by searching the PubMed database for hip aseptic loosening. We included meta-analysis, randomized controlled trials, reviews, and systematic reviews in the last 10 years, which provided information on techniques that can prevent aseptic loosening in total hip arthroplasty. From a total of 3205 articles identified, 69 articles (2%) met the inclusion criteria, leading to a total of 36 recommendations. A lot of research has been conducted in terms of septic loosening in the last decade. Currently, we have various techniques by which we can reduce the rate of aseptic loosening. Nevertheless, further randomized clinical trials are needed to expand the recommendations for aseptic loosening prevention.