Comparison of tapered-wedge short and standard-length femoral stems in single-stage bilateral direct anterior total hip arthroplasty

Stem Alignment With the Tapered Wedge Cementless Stem "Accolade II" Does Not Affect Bone Mineral Density Over 5 Years After Total Hip Arthroplasty

Background

This study aimed to investigate the relationship between 3-dimensional (3D) alignment and postoperative bone mineral density (BMD) changes with Accolade II tapered wedge stems, which have a different proximal shape from other tapered wedge stems, up to 5 years after primary total hip arthroplasty.

Methods

We retrospectively analyzed the hips of 89 patients who underwent total hip arthroplasty using the second-generation proximally coated cementless stem (Accolade II; Stryker Orthopedics, Mahwah, NJ) at our institution from 2014 to 2018 over a 5-year follow-up. We evaluated the relationship between stem alignment, measured using 3D-templating software, and BMD changes in the 7 Gruen zones and compared the data with those from a former study using other short taper-wedge stems.

Results

BMDs in zones 1 and 7 continued to decrease gradually every year after surgery, and BMD in zone 7 showed the largest decrease (21%) from baseline over 5 years. No correlation was found between stem alignment (varus/valgus, flexion/extension, and anteversion/retroversion) and changes in BMD in each zone over 5 years.

Conclusions

Our data showed no correlation between 3D stem alignment and changes in BMD in each Gruen zone over 5 years. This suggests that the Accolade II stem may fit better into any shape of the proximal medullary canal because of its unique characteristics.

Comparison of Perioperative Outcomes and Early Complications Between a Direct Anterior Approach or Posterolateral Approach in Simultaneous Bilateral Total Hip Arthroplasty: A Retrospective Study

Background: Controversies remain on the best surgical approaches for unilateral total hip arthroplasty (THA). There are little data on simultaneous bilateral THA via direct anterior approach (SimBDAA-THA) or posterolateral approach (SimBPA-THA). Purpose: We sought to assess differences in perioperative outcomes and early medical and surgical complications between SimBDAA-THA and SimBPA-THA. Methods: This retrospective study involved patients who underwent either SimBDAA-THA in a supine position (n = 73) or SimBPA-THA in a lateral position (n = 162) at our institution from January 2015 to November 2021. The 2 groups were compared in terms of clinical and demographic characteristics, surgical parameters, and complications during 6-months of follow-up. Results: There were no differences in clinical and demographic characteristics between the 2 groups prior to surgery. Simultaneous bilateral THA via direct anterior approach significantly shortened the length of both the operation (117.50 ±19.42 vs 143.97 ± 32.20 min) and the hospitalization (140.64 ± 43.22 vs 156.24 ± 56.64 h) but increased perioperative loss of hemoglobin (3.28 ± 1.01 vs 3.21 ± 2.26 g/dL). There were no significant differences between the two groups in transfusion rate; levels of interleukin-6, C-reactive protein or creatine kinase; or complications. Conclusion: This retrospective study of patients at a single institution found minimal differences in perioperative outcomes or early medical and surgical complications between SimBDAA-THA and SimBPA-THA except operative time and length of hospitalization. Larger studies with longer follow-up should be conducted to identify whether a direct anterior approach is superior to a posterolateral one.

Can We Predict Fracture When Using a Short Cementless Femoral Stem in the Anterior Approach?

BACKGROUND

Short cementless femoral stems may allow for easier insertion with less dissection. The use of short stems with the anterior approach (AA) may be associated with a considerable perioperative fracture risk. Our aim was to evaluate whether patient-specific femoral and pelvic morphology and surgical technique, influence the perioperative fracture risk. Furthermore, we sought to describe important anatomical thresholds alerting surgeons.

METHODS

A single-center, multi-surgeon retrospective, case-control matched study was performed. Thirty nine periprosthetic fractures (3.4%) in 1,145 primary AA THAs using short cementless stems were identified. These were matched with 78 THA nonfracture controls for factors known to increase the fracture risk. A radiographic analysis using validated software measured femoral (canal flare index [CFI], morphological cortical index [MCI], and calcar-calcar ratio [CCR]) and pelvic (Ilium-ischial ratio [IIR], ilium overhang, and anterior superior iliac spine [ASIS] to greater trochanter distance) morphologies and surgical techniques (% canal fill). A multivariate and Receiver-Operator Curve (ROC) analysis was used to identify fracture predictors.

RESULTS

CFI (3.7 ± 0.6 vs 2.9 ± 0.4, P < .001) and CCR (0.5 ± 0.1 vs 0.4 ± 0.1, P = .006) differed. The mean IIR was higher in fracture cases (3.3 ± 0.6 vs 3.0 ± 0.5, P < .001). Percent canal fill was reduced in fracture cases (82.8 ± 7.6 vs 86.7 ± 6.8, P = .007). Multivariate and ROC analyses revealed a threshold CFI of 3.17 which was predictive of fracture (sensitivity: 84.6%/specificity: 75.6%). The fracture risk was 29 times higher when patients had CFI >3.17 and II ratio >3 (OR: 29.2 95% CI: 9.5-89.9, P < .001).

CONCLUSION

Patient-specific anatomical parameters are important predictors of a fracture-risk. A careful radiographic analysis would help identify those at a risk of early fracture using short stems, and alternative stem options should be considered.