Survivorship, complications and patient-reported outcomes in calcar-guided short-stem THA: prospective mid-term multicenter data of the first 879 hips

Calcar-guided short-stem total hip arthroplasty in fractures of the femoral neck: a prospective observational study of 68 hips

INTRODUCTION

The indications for cementless short-stem total hip arthroplasty (THA) have been expanded due to encouraging results. However, no evidence in cases of femoral neck fractures (FNFs) is available. We aimed to prospectively obtain data on the safety and the clinical outcomes of a cementless calcar-guided short stem in patients with FNFs.

MATERIALS AND METHODS

We conducted a prospective observational study of 68 patients diagnosed with FNFs who underwent short-stem THA between 2016 and 2019 with a calcar-guided stem. Complications during follow-up leading to revision were documented, and patient reported outcome measurements recorded. Stem migration was analyzed using the Einzel-Bild-Röntgen-Analysis Femoral Component Analysis software.

RESULTS

The mean follow-up was 33.8 ± 14.8 months. The patient mortality at last follow-up was 10.6%. Two patients required stem revision, due to periprosthetic fracture and late aseptic loosening, respectively, corresponding to 96.2% stem survival. Survivorship for the endpoint of revision for any reason was 91.1% at 6 years. All revisions occurred in females. The mean Harris Hip Score at the last follow-up was 93.0 ± 8.9. The mean axial migration at last follow-up was 1.90 ± 1.81 mm. No significant influence on migration was found regarding gender, age, weight, and body mass index.

CONCLUSIONS

The clinical and radiological findings were satisfying and most patients benefited from the minimally invasive procedure. However, as for conventional THA as well, implant survivorship and mortality were markedly worse compared to results regarding osteoarthritis. Especially in elderly female patients with FNF, cementless short-stem THA is a concern and a cemented THA should be the first choice.

Mid-term survival of the Optimys short stem: A prospective case series of 500 patients

BACKGROUND

In recent years, there has been an increase in the number of total hip arthroplasty procedures in the younger patient population. This active group has higher expectations of their prosthesis in comparison to the older population, and there is a greater physical demand for the prosthesis. Short femoral stems were introduced to retain proximal bone stock and joint biomechanics and became more common to implant in this specific population. Currently, the long-term survival and functional outcomes of various short stems are still being investigated in different clinics.

AIM

To determine the 5-year survival of the Optimys hip stem.

METHODS

This was a prospective multicenter cohort study of 500 patients conducted in two hospitals in the Netherlands. All patients received the Optimys short stem (Mathys Ltd, Bettlach, Switzerland). The primary outcome measure was survival of the hip stem, with revision as the endpoint. The secondary outcome measurements included patient-reported outcome measures (PROMs). Kaplan-Meier analysis was used to calculate the 5-year survival rate. Log-minus-log transformation was performed to calculate the 95% confidence interval (95%CI). Mixed model analyses were performed to assess the course of the PROMs during the 1st 2 years after surgery. Analyses were modeled separately for the 1st and 2nd years to calculate the yearly change in PROMs during both follow-up periods with accompanying 95%CIs.

RESULTS

The mean age of the total 500 patients was 62.3 years (standard deviation: 10.6) and 202 were male (40%). At a median follow-up of 5.5 years (interquartile range: 4.5-6.7), 7 patients were deceased and 6 revisions were registered, for infection (n = 3), subsidence (n = 2) and malposition (n = 1). This resulted in an overall 5-year survival of 98.8% (95%CI: 97.3-99.5). If infection was left out as reason for revision, a stem survival of 99.4% (95%CI: 98.1-99.8) was seen. Baseline questionnaires were completed by 471 patients (94%), 317 patients (63%) completed the 1-year follow-up questionnaires and 233 patients (47%) completed the 2-year follow-up. Both outcome measures significantly improved across all domains in the 1st year after the operation (P < 0.03 for all domains). In the 2nd year after surgery, no significant changes were observed in any domain in comparison to the 1-year follow-up.

CONCLUSION

The Optimys stem has a 5-year survival of 98.8%. Patient-reported outcome measures increased significantly in the 1st postoperative year with stabilization at the 2-year follow-up.

Subsidence analysis of a cementless short stem THA using EBRA-FCA - A seven-year prospective multicentre study

Background

Metaphyseal fixation of short stem THA allows for minimally invasive surgery, less bone removal, improved bone load transfer and reduced stress shielding. Short stems facilitate the anatomic restoration i.a. of leg length, femoroacetabular offset, and center of rotation. However, metaphyseal fixation might cause impaired primary and/or secondary stability resulting in an inherent tendency for early axial migration and aseptic loosening eventually. The objective of this study was to investigate the long-term outcome and migration pattern of a calcar-guided short stem.

Methods

In a prospective multicenter study, 213 patients (224 THAs) were enrolled. Patients were followed for up to 84 months postoperatively. Clinical outcome was assessed using the Harris Hip Score and the VAS for pain and satisfaction. Standardized and calibrated radiographs were screened i.a. for stress shielding and loosening. Einzel-Bild-Roentgen-Analyse - femoral component analysis (EBRA-FCA) was used to detect longitudinal subsidence.

Results

At 7 year follow-up, n = 139/224 cases were available for analysis. All clinical parameters improved significantly (p < 0.001) and improvement persisted. There were no radiographic changes indicating stress shielding. EBRA-FCA revealed a mean subsidence of -1.44 mm followed by a stabilization. Weight >80 kg (p = 0.115), BMI <30 kg/m2 (p = 0.282), male gender (p = 0.246), and age <65 years (p = 0.304) seemed to be associated with a higher risk for migration. The cumulative revision rate was 2.23%. Revisions due to stem migration (0.89%) occurred early (mean time between index surgery and revision: 3.3 months).

Conclusions

If at all, there appears to be a pronounced initial subsidence, which stabilizes thereafter. Stem migration was rarely a compelling reason for failure or revision. Demographics do not seem to have a significant effect on migration pattern. The absence of radioluce lines, resorption or hypertrophy of the proximal femora support the hypothesis of a reduced stress shielding for metaphyseal anchoring short stems.