Periprosthetic Femoral Fractures in Cementless Short Versus Straight Stem Total Hip Arthroplasty: A Propensity Score Matched Analysis

[Periprosthetic fracture in hip replacement-risk factors and treatment]

BACKGROUND

Periprosthetic acetabular fractures primarily pose a problem with cementless implantation techniques and occur in approximately 3.6% of primary and up to 20.9% of revision cases. When a fracture situation exists that affects the integrity of the pelvic columns, stabilization using plate osteosynthesis is necessary, in addition to the implantation of a revision cup. Periprosthetic femoral fractures also primarily occur with cementless techniques and account for 0.4-6.8% of revisions after primary total hip arthroplasty. In addition to the cementless technique, the most common risk factors for the development of PFF are a minimally invasive, ventral approach, female gender, poor bone quality, age > 75 years, and revision surgery.

TREATMENT

Depending on the degree of risk to the stability of the implant, conservative or surgical treatment can be carried out using osteosynthesis, stem replacement or a combination of both procedures.

Periprosthetic femoral fractures in minimally-invasive anterolateral short stem versus transgluteal straight stem cementless total hip arthroplasty: What are the differences in the femoral and pelvic morphology?

BACKGROUND

The occurrence of periprosthetic femoral fractures (PFFs) in cementless total hip arthroplasty (THA) might be associated with the proximal femoral morphology and the pelvis. PFFs in short stem THA are associated with an increased Canal Flare Index. PFFs in straight stem THA show a decreased Canal Flare Index. Therefore, this study aims to compare the femoral and pelvic geometry in PFFs between short stem and straight stem THA.

METHODS

A retrospective comparative propensity-score matched study was performed. An institutional database of 5358 THAs was screened for early PFFs within the first 90 days after surgery. All cases of 136 PFFs in primary cementless THA were collected and matched, resulting in 67 PFFs in the straight stem and 37 PFFs in the short stem group. Both groups were analyzed regarding several parameters for femoral and pelvic morphology.

RESULTS

A significantly lower distance from the anterior superior iliac spine to the greater trochanter (AGT) was detected in the straight stem group (96.4 vs. 104.8 mm, p = 0.024). All other femoral and pelvic parameters did not differ between both groups. Postoperative Vancouver A PFFs were significantly higher in straight stem THA, while postoperative Vancouver B PFFs were significantly higher in short stem THA.

CONCLUSION

The morphology of the proximal femur and the pelvis do not differ in several radiological parameters in patients sustaining a PFF between cementless short stem implanted via an anterolateral approach and straight stem THA implanted via a transgluteal approach. While there are differences in the Vancouver types of PFFs, these differences do not reflect any difference in the morphology of the proximal femur and the pelvis.

Biomechanical analysis of a short femoral stem used in revision total hip replacement of a standard femoral stem

Short-stem total hip arthroplasty (SHA) has become popular because it preserves femoral bone stock and enables the use of short femoral stems in revision total hip arthroplasty (THA). However, no study has evaluated whether a short stem in revision THA, replacing a standard stem, can provide adequate primary stability to facilitate osseous integration. In this biomechanical study, a metaphyseal anchoring SHA (Tri-Lock BPS) stem and a standard THA (Corail) stem were implanted into ten composite femurs and loaded dynamically from 300 to 1700 N with 1 Hz. Primary stability was estimated using three-dimensional (3D) micromotions at five points around the bone-implant interface. A revision scenario was then established by removing the standard stem and implanting the same Tri-Lock BPS stem, with subsequent measurements of 3D micromotions. In the primary scenario, no significant differences in 3D micromotions were noted between the short and standard stems at most of the test points. Compared with the Corail group, the Tri-Lock BPS group presented significantly greater 3D micromotions only at the lateral point of the distal femur (P5: Tri-Lock BPS 32.9 ± 7.54 μm vs. Corail 25.1 ± 4.32 μm; p = 0.011). In the revision scenario, no significant differences in the 3D micromotions were noted between the primary and revision Tri-Lock BPS stems at all test points. Our results show that the SHA (Tri-Lock BPS) offers good primary stability, which is similar to that of the standard THA (Corail). The Tri-Lock BPS stem obtained comparable stability in this revision scenario as in the primary scenario; therefore, it can be assumed that the Corail standard stem can safely be revised with a Tri-Lock BPS short stem.

Is there a difference in pelvic and femoral morphology in early periprosthetic femoral fracture in cementless short stem total hip arthroplasty via an anterolateral approach?

BACKGROUND

The pelvic and femoral morphology are associated with the occurrence of early periprosthetic femoral fractures (PFFs) in cementless total hip arthroplasty (THA). Differences exist depending on the performed approach and implanted stem design. Therefore, this study was conducted to analyze the pelvic and femoral morphology in cementless short stem THA via a minimally-invasive (MIS) anterolateral approach.

METHODS

A retrospective, single-center, multi-surgeon, comparative propensity-score matched study of a cohort of 1826 short stem THAs was conducted. A total of 39 PFFs within the first 90 days after surgery was matched on a 2:1 ratio to non-fracture patients. The morphology of the proximal femur was analyzed with canal flare index (CFI), canal-calcar ratio (CCR), canal-bone ratio (CBR), morphological cortical index (MCI), and femoral cortical index (CI). The pelvic morphology was analyzed with ilium-ischial ratio (IR), distance anterior superior iliac spine to the tip of the greater trochanter (AGT). Both groups were analyzed regarding several parameters for femoral and pelvic morphology in non-parametric testing and univariate regression analysis.

RESULTS

A significantly higher AGT was detected in the fracture group (104.5 mm ± 18 versus 97.4 mm ± 9.8; p = 0.016). All other femoral and pelvic parameters did not differ between both groups, also when compared depending on the Vancouver type of the PFF.

CONCLUSIONS

The morphology of the proximal femur and the pelvis do not differ in several radiological parameters in patients sustaining a PFF in cementless short stem THA via an anterolateral approach compared with matched non-fracture group. The findings are controversial to other studies with different stem types and approaches. Future studies should focus on analyzing the influence of the pelvic geometry and the shape of the proximal femur in the occurrence of PFFs in different approaches with the same stem type and vice versa. Level of Evidence Level III case-controlled study.

Learning curve comparison between switching approach and switching implant in cementless short stem total hip arthroplasty

INTRODUCTION

Implementing new approaches or new implants is always related with a certain learning curve in total hip arthroplasty (THA). Currently, many surgeons are switching to minimally invasive approaches combined with short stems for performing THA. Therefore, we aimed to asses and compare the learning curve of switching from an anterolateral Watson Jones approach (ALA) to a direct anterior approach (DAA) with the learning curve of switching from a neck-resecting to a partially neck-sparing short stem in cementless THA.

MATERIALS AND METHODS

The first 150 consecutive THA performed through a DAA (Group A) and the first 150 consecutive THA using a partially neck-sparing short stem (Group B) performed by a single surgeon were evaluated within this retrospective cohort study. All cases were screened for surgery related adverse events (AE). Furthermore, the operative time of each surgery was evaluated and the learning curve assessed performing a cumulative sum (CUSUM) analysis.

RESULTS

Overall, significantly more AE occurred in Group A compared to Group B (18.0% vs. 10.0%; p = 0.046). The sub-analysis of the AE revealed higher rates of periprosthetic joint infections (2.7% vs. 0.7%; p = 0.176), periprosthetic fractures (4.0% vs. 2.0%; p = 0.310) and overall revisions (4.7% vs. 1.3% p = 0.091) within Group A without statistical significance. The CUSUM analysis revealed a consistent reduction of operative time after 97 cases in Group A and 79 cases in Group B.

CONCLUSION

A significantly higher overall rate of AE was detected while switching approach compared to switching implant for performing THA. However, according to the results of this study, surgeons should be aware of the learning curve of the adoption to a new implant with different fixation philosophy as well.

Cemented Calcar-Guided Short-Stem Prostheses in Geriatric Patients: Short-Term Results from a Prospective Observational Study

Both cementless and cemented stems have exhibited favorable long-term outcomes in total hip arthroplasty. Nonetheless, in elderly patients, cemented hips offer an advantage due to their reduced risk of periprosthetic fractures. This study aimed to assess the initial outcomes of 28 patients who underwent unilateral cemented total hip arthroplasty utilizing a calcar-guided A2 stem (ARTIQO GmbH, Lüdinghausen, Germany). Various types of antibiotic-loaded bone cement were employed. During follow-up, we recorded demographic data and comorbidities and employed standardized clinical assessment tools, including the Harris Hip Score. Radiographic assessments included preoperative, postoperative, and follow-up imaging to evaluate subsidence, osteolysis, and bone resorption. The results indicated that among the 28 patients, 5 withdrew consent and 2 patients passed away from unrelated causes. Additionally, one prosthesis was explanted due to the undersizing of the cement stopper, which resulted in an inadequate cement mantle. As a result, 20 patients underwent a 1-year follow-up, revealing noteworthy enhancements in clinical scores, with no instances of radiolucent lines or osteolysis. No infections were detected. In summary, our short-term experience with this particular cemented short-stem design yielded promising results, exhibiting excellent functional outcomes, no aseptic loosening attributable to the stem, and no infections. Further clinical studies and registry data are essential to corroborate these findings.

Cementless short stem total hip arthroplasty in patients older than 75 years: is it feasible?

BACKGROUND

In recent years, the indication for cementless short stem total hip arthroplasty (THA) has been widened to elderly patients as they might profit by the advantages of the short-curved implant design as well. Therefore, this study was conducted to evaluate the clinical and radiological outcome of a cementless short stem in elderly patients (≥ 75 years) compared to a young control group (≤ 60 years).

METHODS

A retrospective cohort of 316 THAs performed between 2014 and 2017 was prospectively examined. In all patients a cementless, curved short stem and press-fit cup (Fitmore® stem; Allofit®/-S cup; both ZimmerBiomet, Warsaw, IN, USA) were implanted via a minimally-invasive anterolateral approach. Clinical and radiological outcome as well as rate of complications and revision were assessed.

RESULTS

In total, 292 patients have been included for analysis of complications and revisions (Øfollow-up: 4.5 years) and 208 patients for clinical and radiological outcome (Øfollow-up: 4.4 years). Complication rate was significantly increased in elderly patients (13.7% vs. 5.8%, p = 0.023), while the revision rate was increased without statistical significance (5.2% vs. 2.2%, p = 0.169). Periprosthetic fractures occurred significantly higher in the elderly patients (5.2% vs. 0.7%; p = 0.026). Both groups showed a comparable clinical outcome in the Harris Hip Score (93.7 vs. 91.9; p = 0.224), Oxford Hip Score (44.5 vs. 43.7; p = 0.350), Forgotten Joint Score (81.7 vs. 81.5; p = 0.952) and WOMAC (7.4 vs. 9.3; p = 0.334).

CONCLUSION

Cementless short stem total hip arthroplasty shows a comparable clinical and radiological outcome in patients over 75 years of age compared to younger patients under 60 years of age. However, cementless shorts stem THA shows an increased rate of overall complications and periprosthetic fractures in elderly patients over 75 years of age. Cemented fixation of the femoral component should be considered in patients over 75 years of age.

LEVEL OF EVIDENCE

III Case-controlled study.

TRIAL REGISTRATION

Observational study without need for trial registration due to ICMJE criteria.

Analysis of Postoperative Complication and Revision Rates and Mid- to Long-Term Implant Survival in Primary Short-Stem Total Hip Arthroplasty

Background/Objectives: Short-stem prostheses were introduced as an alternative to conventional straight-stem prostheses. Despite their benefits, including minimally invasive approaches, soft-tissue- and bone-sparing implantation, and physiological load transfer to the metaphysis, data on postoperative complication and revision rates as well as on implant survival are scarce. Methods: A retrospective analysis of 1327 patients who underwent primary total hip arthroplasty (THA) using the Metha® short stem between 2006 and 2023 was conducted. Complication and revision rates were analysed for the intraoperative, direct postoperative, and follow-up episodes. Implant survival was analysed with the endpoint of all-cause stem revision. Results: Intraoperative complications were observed in 3.77% of the cases and included 44 hairline cracks and 6 fractures. In 15 cases (30.0%), conversion to a straight-stem or revision implant was necessary. The direct postoperative complication rate was 2.44%, and 11 revision procedures were performed during inpatient stay (0.84%). Mean follow-up was 7 years (range 1-17). During follow-up, femoral component revision was performed in 60 cases. Aseptic loosening and stem subsidence accounted for a combined percentage of 80% of all indications. Implant survival rate was 95.66% after 5 years, 95.58% after 10 years, and 95.50% after 15 years. Conclusions: Our study provides a comprehensive analysis of postoperative complication and revision rates in a large sample undergoing primary short-stem THA. Postoperative complication rates were favourable, and the long-term implant survival rates were comparable to conventional straight-stem prostheses. Therefore, short-stem THA may be considered an alternative for younger patients.

Periprosthetic Hip Fractures around the Stem: Can the Stem Design Affect Fracture Features?

Background: Total hip arthroplasty is one of the most successful orthopedic surgeries; nevertheless, many of these surgeries are the causes of failure, and among them, periprosthetic fractures are one of the major causes of revision. Our study focuses on periprosthetic hip fractures with two different stem designs. The aim of the study was to analyze the obtained results, focusing on the features of periprosthetic stem fractures observed. Methods: We retrospectively reviewed periprosthetic fractures occurring between 2010 and 2023, involving Alloclassic® or CLS® uncemented femoral stems. We analyzed demographic data, proximal femur morphology, and the fracture type. Results: We identified 97 patients. Considering the proximal femur morphology, we found that there was statistically significant prevalence of Dorr A proximal femur morphology in the CLS® group and of Dorr C in the Alloclassic® group. Considering the distribution of the fracture pattern, we reported a non-statistically significant prevalence of the fracture pattern with stable stems in the CLS® group. Conclusions: The choice of the prosthetic design of the femoral stem is a crucial element when planning total hip arthroplasty. However, we found a non-statistically significant difference between the two stems considered, raising questions about the real role of stem design as a primary determinant of periprosthetic hip fractures.

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.