No difference in outcome or migration but greater loss of bone mineral density with the Collum Femoris Preserving stem compared with the Corail stem: a randomized controlled trial with five-year follow-up

Contact states with femoral cortical bone and periprosthetic bone mineral density changes differ between traditional and newly introduced fully hydroxyapatite-coated stems

Aims

The aim of this study was to compare the pattern of initial fixation and changes in periprosthetic bone mineral density (BMD) between patients who underwent total hip arthroplasty (THA) using a traditional fully hydroxyapatite (HA)-coated stem (T-HA group) and those with a newly introduced fully HA-coated stem (N-HA group).

Methods

The study included 36 patients with T-HA stems and 30 with N-HA stems. Dual-energy X-ray absorptiometry was used to measure the change in periprosthetic BMD, one and two years postoperatively. The 3D contact between the stem and femoral cortical bone was evaluated using a density-mapping system, and clinical assessment, including patient-reported outcome measurements, was recorded.

Results

There were significantly larger contact areas in Gruen zones 3, 5, and 6 in the N-HA group than in the T-HA group. At two years postoperatively, there was a significant decrease in BMD around the proximal-medial femur (zone 6) in the N-HA group and a significant increase in the T-HA group. BMD changes in both groups correlated with BMI or preoperative lumbar BMD rather than with the extent of contact with the femoral cortical bone.

Conclusion

The N-HA-coated stem showed a significantly larger contact area, indicating a distal fixation pattern, compared with the traditional fully HA-coated stem. The T-HA-coated stem showed better preservation of periprosthetic BMD, two years postoperatively. Surgeons should consider these patterns of fixation and differences in BMD when selecting fully HA-coated stems for THA, to improve the long-term outcomes.

Anterior Minimally Invasive Approach (AMIS) for Total Hip Arthroplasty: Analysis of the First 1000 Consecutive Patients Operated at a High Volume Center

(1) Background: Direct anterior approach (DAA) has recently acquired popularity through improvements such as the anterior minimally invasive surgical technique (AMIS). This retrospective study examines the first 1000 consecutive THAs performed utilizing the AMIS approach in a high-volume center between 2012 and 2017. (2) Methods: 1000 consecutive THAs performed at a single institution utilizing the AMIS approach were retrospectively analyzed with a minimum five-year follow-up. Full evaluation of demographic information, clinical parameters, intraoperative complications, and radiological examinations are reported. (3) Results: Overall complication rate was 9.4% (94/1000), including 8 dislocations, 57 femoral-cutaneous nerve injuries, 12 intraoperative femoral fractures, 9 infections and 8 leg length discrepancy. Implant survival rates were 98.5% at 1 year, 97.5% at 3 years, 97% at 5 years, and 95.3% at 7 years. Causes of failure included periprosthetic fractures (0.8%), implant dislocations (0.6%), septic loosening (0.5%), aseptic mobilizations (0.2%), and symptomatic limb length discrepancies (0.2%). (4) Conclusions: Controversies persist around the direct anterior approach (DAA) for THA, primarily regarding the increased complications rate during the learning curve. However, this study advocates for widespread adoption of the DAA approach. The results demonstrate acceptable complication rates and remarkable functional outcomes, affirming its viability in the broader orthopedic patient population.

Short versus conventional straight stem in uncemented total hip arthroplasty: functional outcomes up to 5 years and survival up to 12 years: secondary results of a randomized controlled trial

BACKGROUND AND PURPOSE

To date, the mid- and long-term outcomes of the Collum Femoris Preserving (CFP) stem compared with conventional straight stems are unknown. We aimed to compare physical function at a 5-year follow-up and implant survival at an average of 10-year follow-up in an randomized controlled trial (RCT).

METHODS

This is a secondary report of a double-blinded RCT in 2 hospitals. Patients aged 18-70 years with hip osteoarthritis undergoing an uncemented primary THA were randomized to a CFP or a Zweymüller stem. Patient-reported outcomes, clinical tests, and radiographs were collected at baseline, 2, 3, 4, and 5 years postoperatively. Primary outcome was the Hip disability and Osteoarthritis Outcome Score (HOOS) function in activities of daily living (ADL) subscale. Secondary outcomes were other patient-reported outcomes, clinical tests, adverse events, and implant survival. Kaplan-Meier and competing risk survival analyses were performed with data from the Dutch Arthroplasty Registry.

RESULTS

We included 150 patients. Mean difference between groups on the HOOS ADL subscale at 5 years was -0.07 (95% confidence interval -5.1 to 4.9). Overall survival was 92% for the CFP and 96% for the Zweymüller stem. No significant difference was found.

CONCLUSION

No significant differences were found in physical function at 5-year and implant survival at 10-year follow-up between the CFP and Zweymüller stems. When taking cup revisions into account, the CFP group showed clinically inferior survival.

2-Year Radiostereometric Analysis Evaluation of a Short, Proximally Coated, Triple-Taper Blade Femoral Stem Versus a Quadrangular-Taper Stem With Reinforced Proximal Body: A Randomized Controlled Trial

BACKGROUND

Cementless stem designs with proximal metaphyseal fixation aim to achieve better load distribution, reduce stress shielding, and improve primary stability. The purpose of this prospective, randomized controlled trial was to evaluate the 2-year migration and clinical outcomes of two cementless femoral stems.

METHODS

A total of 60 participants undergoing primary total hip arthroplasty for any cause were randomly allocated to receiving either a proximally coated, short blade stem or a quadrangular-taper stem with a reinforced proximal body. Radiostereometric Analysis (RSA) radiographs were performed post-operatively and at 6 weeks, 6 months, 1- and 2-years. The Harris Hip Score, Oxford Hip Score and the EuroQol five-dimension (EQ5D) were also collected.

RESULTS

At two years, the median subsidence of the short-blade stem was 0.097 millimeters (mm) [Interquartile range (IQR) -0.67 to 0.08)] versus 0.086 mm(IQR, -0.29 to 0.005, P=0.683); medial translation 0.023 mm (IQR 0.08 to 0.12) versus 0.029 mm(IQR -0.07 to 0.10, P=0.907); anterior translation 0.035 mm (IQR -0.23 to 0.33) versus 0.07 mm (IQR -0.13 to 0.08, P=0.268). At 24 months postoperatively, there were no stem revisions and Patient Reported Outcome Measures (PROMs) were comparable between groups.

CONCLUSION

Both cementless stems exhibited a predictable migration pattern and achieved initial stability. There was no difference in migration across the three Cartesian axes at any timepoint. Clinical outcomes and PROMs were also comparable. Biological fixation of both implants evidenced by the RSA and excellent PROMs are likely to translate to longer-term stability, which would need to be corroborated by longer-term outcome studies.

Effect of femoral stem surface coating on clinical and radiographic outcomes of cementless primary total hip arthroplasty: a patient-matched retrospective study

PURPOSE

This study aims to determine whether changing the stem coating grants superior outcomes at a minimum follow-up of five years.

METHODS

Retrospective review of a consecutive series of primary total hip arthroplasties (THAs) operated by direct anterior approach between 01/01/2013 and 31/12/2014. Two stems were compared, which were identical except for their surface coating; "the Original stem" was fully coated with hydroxyapatite (HA), while "the ProxCoat stem" was proximally coated with plasma-sprayed titanium and HA. Matching was performed. Clinical assessment included modified Harris hip score (mHHS), Oxford hip score (OHS), and forgotten joint score (FJS). Radiographic assessment evaluated alignment, subsidence, pedestal formation, heterotopic ossification, radiolucent lines ≥ 2 mm, spot welds, cortical hypertrophy, and osteolysis.

RESULTS

232 hips received the Original stem and 167 the ProxCoat stem, from which respectively five hips (2.2%) and no hips (0%) underwent revision. Matching identified two groups of 91 patients, with comparable patient demographics. At > five years follow-up, there were no differences in OHS (16 ± 6 vs 15 ± 5; p = 0.075) nor FJS (81 ± 26 vs 84 ± 22; p = 0.521), but there were differences in mHHS (89 ± 15 vs 92 ± 12; p = 0.042). There were no differences in alignment, subsidence, pedestal formation, heterotopic ossification, cortical hypertrophy, and osteolysis. There were differences in prevalence of proximal radiolucent lines (12% vs 0%; p < 0.001) and distal spot welds (24% vs 54%; p < 0.001).

CONCLUSION

At a minimum follow-up of five years, this study on matched patients undergoing primary THA found that ProxCoat stems results in significantly fewer radiolucent lines, more spot welds, and less revisions than Original stems, thus suggesting better bone ingrowth.