The morphology of the proximal femur in cementless short-stem total hip arthroplasty: No negative effect on offset reconstruction, leg length difference and implant positioning

Mid-Term to Long-Term Outcomes of Total Hip Arthroplasty Using a Cementless Trochanteric Sparing Short Stem Through Direct Anterior Approach: A Single-Center Study

BACKGROUND

Total hip arthroplasty (THA) is increasingly performed in younger patients, necessitating long-term femoral bone preservation. Metaphyseal engaging short stems offer potential benefits by reducing stress shielding and preserving bone stock. However, lacking long-term data in large quantities and younger patients in the literature led this study to assess mid-term to long-term outcome of these short stems.

METHODS

This retrospective study evaluated the long-term outcomes of 755 hips (667 patients) underwent THA using the Fitmore stem via a direct anterior approach. Clinical and radiographic assessments were conducted, and survival rates were determined using Kaplan-Meier analyses. Statistical analyses were performed to identify associations and predictors of stem revision.

RESULTS

The overall survival rate for the Fitmore stem was 92.11% at an average follow-up of 10 years. No revisions were performed due to aseptic loosening of the femoral component. Stem revisions were performed in 20 hips, primarily due to periprosthetic fractures followed by periprosthetic joint infections and recurrent dislocations. The clinical outcomes showed significant improvements in HHS, WOMAC Index, and VAS pain scores. Radiographic analysis revealed acceptable rates of complications, with minimal stem subsidence, no severe bone loss, and a low incidence of radiolucent lines and cortical hypertrophy.

CONCLUSIONS

The Fitmore stem demonstrated favorable mid-term to long-term outcomes in terms of implant survival, functional scores, and radiographic assessments even in younger populations. The findings contribute to the existing body of knowledge on the Fitmore stem's efficacy and safety in preserving bone and achieving satisfactory clinical outcomes in THA.

LEVEL OF EVIDENCE

IV.

Relating total hip replacement and acetabular cup positioning with outcome: A systematic review

The diverse methodologies employed in assessing cup placement, delineate the recommended target zones for positioning and examine the correlation between cup positioning and occurrences of complications is of interest. We included 51,308 patients and 51,692 hips for this analysis. The overall complication rate was 22.2%. Patients, overall, demonstrated improved outcomes, as evidenced by postoperative hip scores. Two "safe windows" have been defined for surgical procedures: 1) an inclination of 35-50 degrees and an anteversion of 5-25 degrees and 2) an inclination of 35-50 degrees and an anteversion of 15-25 degrees.

Optimal Bone Preparation for Triple-Tapered Stems: Does the Sagittal Taper Affect Optimal Femoral Sizing?

Background

Conventional single-tapered, total hip arthroplasty stems achieve fixation namely through coronal, metaphyseal fit. Triple taper stems have a sagittal taper to optimize fixation in the antero-posterior (AP) plane as well; however, limited guidance exists on appropriate bone preparation. Often, similar preparation techniques are used despite geometric differences which may lead to underpreparation. We've defined a novel technique in which a small portion of posterior femoral neck and cancellous bone is removed to permit preparation collinear to the diaphyseal sagittal femoral axis. We hypothesize this will optimize stem fit and stability compared to conventional techniques.

Methods

This is a retrospective review of 38 cementless primary total hip arthroplasty cases performed by a single surgeon. In each case, broach preparation was initially performed through the center of the femoral neck as although it was a single-tapered stem. Once tactile sensation of adequate fit was achieved, fluoroscopic images were taken to document AP and mediolateral fit, and stem size was recorded. Then that broach was removed, and a standardized one-third of the posterior femoral neck and posterior cancellous bone was removed, permitting broaches to prepare the femur collinear to the femoral diaphyseal sagittal axis- triple-tapered preparation (TTP). Outcomes included change in stem size from initial broach trial to final stem selection and radiographic stem fill on AP and lateral views.

Results

Median single-tapered preparation broach size was 8 (range, 5-12) and final stem size after TTP was 11 (range, 6-13). The TTP overall mean percent metaphyseal fill was 74 ± 6% in the AP view and 71 ± 5% in the lateral view, both significantly higher than single-tapered preparation which was 67 ± 7% and 65 ± 7%, respectively (P < .001). No fractures or loosening occurred in this series.

Conclusions

Preparation of triple-tapered stems collinear to the diaphyseal sagittal femoral axis improves stem size, fit, and fill.

Leg length discrepancy risk differs between fit-and-fill and taper wedge stems across Dorr types

INTRODUCTION

The comparison between the cementless taper wedge stem and fit-and-fill stem in total hip arthroplasty (THA) for various proximal femoral morphological types has not been thoroughly assessed. This study aimed to compare the risk of leg length discrepancy (LLD) ≥ 10 mm between these two stem types in Dorr type A, B, and C femurs.

MATERIALS AND METHODS

From April 2015 through April 2021, we analyzed 1178 unilateral primary cementless THA procedures. We categorized all procedures into three groups: Dorr type A (N = 220, 18.7%), B (N = 875, 74.3%), and C (N = 83, 7.0%). Within each Dorr type, we compared the incidence and risk of postoperative LLD ≥ 10 mm between the two stem types. The factors considered in the multivariate regression analyses included stem type, age, sex, body mass index, diagnosis, canal flare index, femoral cortical index and stem alignment.

RESULTS

The taper wedge stem group had a higher overall incidence of LLD ≥ 10 mm (12.8% vs. 7.4%, P = 0.012) and in Dorr type A femurs (22.2% vs. 7.6%, P = 0.014), compared with the fit-and-fill stem group. In multivariate analysis, the taper wedge stem exhibited an increased risk of LLD ≥ 10 mm only in Dorr type A femurs (aOR: 3.449, 95% CI: 1.325-8.794). The incidence and risk of LLD ≥ 10 mm were not different between the two stems in Dorr type B and C femurs.

CONCLUSIONS

The taper wedge stem demonstrated an elevated risk of LLD ≥ 10 mm in Dorr type A femurs compared with the fit-and-fill stem, necessitating meticulous preoperative templating and intraoperative femoral canal preparation.

The influence of prosthetic positioning and proximal femoral morphology on leg length discrepancy and early clinical outcomes of cementless total hip arthroplasty

BACKGROUND

Leg length discrepancy (LLD) is a common complication of total hip arthroplasty (THA). However, the relationship between femoral prosthesis filling, proximal femoral morphology, and acetabular prosthesis positioning with postoperative LLD and clinical outcomes is unclear. The aims of this study were to investigate the influence of canal flare index (CFI), canal fill ratio (CFR), center of rotation (COR), and femoral offset (FO) on (1) postoperative LLD; and (2) clinical outcomes in the two stem designs with different coating distribution.

METHODS

The study cohort included 161 patients who underwent primary cementless THA between January 2021 and March 2022 with either proximal coating or full coating stems. Multivariate logistic regression was used to assess the effect of CFI, CFR, COR, and FO on postoperative LLD, and linear regression to assess their effect on clinical outcomes.

RESULTS

No statistical difference was found in clinical outcomes or postoperative LLD between the two groups. High CFI (p = 0.014), low ΔVCOR (p = 0.012), and Gender (p = 0.028) were found independent risk factors for LLD one day postoperative. High CFI was also an independent risk factor for postoperative subjectively perceived LLD (p = 0.013). CFR at the level of 2 cm below the LT (p = 0.017) was an independent risk factor for Harris Hip Score.

CONCLUSIONS

Proximal femoral morphology and acetabular prosthesis positioning but not femoral prosthesis filling affected the LLD. High CFI was an independent risk factor for postoperative LLD and subjectively perceived LLD, and low ΔVCOR was also an independent risk factor for postoperative LLD. Women were susceptible to postoperative LLD.

Imageless navigation for primary total hip arthroplasty: a meta-analysis study

BACKGROUND

There has been a growing interest in imageless navigation for primary total hip arthroplasty (THA). Its superiority over standard THA is debated. This meta-analysis compared surgical duration, implant positioning, Harris Hip Score and rate of dislocation of imageless navigation versus conventional THA.

METHODS

The present study was conducted according to the PRISMA 2020 guidelines. All the clinical trials comparing imageless navigation versus conventional for primary THA were accessed. In January 2022, the following databases were accessed: PubMed, Web of Science, Google Scholar and Embase. No time constraints were used for the search. The outcomes of interest were to compare cup inclination and anteversion, leg length discrepancy, surgical duration, Harris Hip Score and rate of dislocation of imageless navigation versus conventional THA.

RESULTS

Twenty-one studies (2706 procedures) were retrieved. Fifty-two percent of patients were women. There was between-group comparability at baseline in terms of age, body mass index (BMI), visual analogue scale, Harris Hip Score and leg length discrepancy (P > 0.1). Compared with conventional THA, the navigated group demonstrated slightly lower leg length discrepancy (P = 0.02) but longer duration of the surgical procedure (P < 0.0001). Cup anteversion (P = 0.6) and inclination (P = 0.5), Harris Hip Score (P = 0.1) and rate of dislocation (P = 0.98) were similar between the two interventions.

CONCLUSION

Imageless navigation may represent a viable option for THA.

Minimally invasive anterolateral approach versus direct anterior approach total hip arthroplasty in the supine position: a prospective study based on early postoperative outcomes

BACKGROUND

Minimally anterolateral approach (MAA) and direct anterior approach (DAA) have been reported as beneficial for total hip arthroplasty (THA) due to their ability to reduce postoperative pain and lead to quicker rehabilitation by preserving muscle insertions. As there is an ongoing debate on the effect of these two approaches on early postoperative outcomes, this prospective study aimed to assess the difference in early clinical, radiological, and patient-reported outcomes between the two minimally invasive approaches.

METHODS

A total of 98 patients, 50 in the MAA group and 48 in the DAA group, were included in the study. Patients with complete data were evaluated preoperatively and postoperatively at 2, 6, and 12 weeks. Clinical measurements, including the ability to climb stairs and walk, 6-min walk test (6MWT), the Forgotten Joint Scale (FJS-12), Japanese Orthopedic Association (JOA) Hip scores, radiological evaluation, and complications were analyzed.

RESULTS

There were no significant differences in clinical outcomes and implant alignments between MAA and DAA groups. In regards to patient-reported outcomes, the FJS-12 was significantly higher in the MAA group compared to group DAA at 2 and 6 weeks postoperatively. However, there was no significant difference in the FJS-12 between the two groups 12 weeks after surgery. The differences also included shorter operative times (62.4 ± 9.05 min vs. 71 ± 8.01 min), less blood loss (132.6 ± 43.31 ml vs. 159.23 ± 37.25 ml), lower Hb drop (29.56 ± 8.02 g/L vs. 36.4 ± 7.12 g/L), and fewer blood transfusions in the MAA group (4.0% vs. 18.8%). The incidence of the lateral femoral cutaneous nerve (LFCN) neuropraxia after surgery was 7 (14.6%) in the DAA group and 0 in the MAA group. One fracture was found in each group and managed conservatively.

CONCLUSION

MAA and DAA approach yielded excellent and similar early clinical outcomes. However, better patient-reported outcomes could be achieved by MAA THA. The MAA resulted in a safer approach associated with shorter operative times, less blood loss, lower Hb drop, fewer blood transfusions, and LFCN neuropraxia than DAA. A longer follow-up is needed to further examine differences between these procedures.

Implant positioning in total hip arthroplasty: influence of horizontal and vertical offset on functionality of prosthetic hip joint

PURPOSE

To analyze the effect of implant position measured in terms of offset on patient reported outcomes (PRO) following hip arthroplasty (THA).

METHODS

A total of 243 patients of the total hip replacement who had a one year follow-up were included in the study. Standard both hips radiograph was used to asses post-surgery implant position in terms of horizontal offset and vertical offset, and correlated with functional outcome which was evaluated as change in PRO. i.e., Harris hip score (HHS) post-op. With center of hip rotation as reference, horizontal offset was calculated as sum of distance, of centre, from proximal femoral shaft axis and a vertical line through ipsilateral teardrop, and vertical offset as limb length discrepancy. Post-op patients were classified into three groups depending on the measurement of horizontal offset of the operated hip. The patients having operated hip horizontal offset within 5 mm of the normal hip were grouped as restored offset (RO); those having shorter or higher offset by more than 5 mm compared to normal hip were labeled as decreased (DO) or increased offset (IO) group respectively. The groups were further subdivided into suboptimal and optimal function groups based on HHS, and among these groups, limb length discrepancy was evaluated.

RESULTS

Post follow-up mean HHS (78.23 ± 9.96) improved significantly in all three groups (p < 0.0001). The difference in post-operative HHS among DO, RO, and IO groups was significant, with their averages being 72.5 ± 4.7, 82.1 ± 6.5, and 75.2 ± 4.8 respectively (p = .01). Limb length discrepancy was significantly more common in patients with suboptimal functional scores in all three groups.

CONCLUSION

This study concluded that both horizontal offset and vertical offset should be reconstructed in patients operated with unilateral THR due to hip pathology, since both factor demonstrated a comparable additive effect on clinical outcome.