Effect of an Alumina Free Device Surface on BMD in Patients Implanted With an SL-PLUS™ Femoral Stem for THA

Study Overview
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Brief Summary
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Alumina particles from the grit blasting of Ti-alloy stems for hip arthroplasty are suspected to contribute to aseptic loosening. An alumina-reduced stem surface was hypothesized to improve osseointegration and show comparable short-term outcomes to those of a standard stem.

Official Title
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A Market Surveillance Study Assessing the Effect of an Alumina Free Device Surface on Bone Mineral Density in Patients Implanted With an SL-PLUS™ Femoral Stem for Total Hip Arthroplasty

Conditions
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Hip Osteoarthritis

Intervention / Treatment
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* Device: SL-PLUS-Stem for total hip arthroplasty


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients aged 18 years and older undergoing primary THA for primary or secondary osteoarthritis will be enrolled. Exclusion Criteria: Exclusion criteria were ongoing therapy with cortisone or medications influencing bone metabolism.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Randomised controlles trial, double-blind. Block randomization with block size 10.
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: STD-SL-PLUS stem<br>Rectangular SL straight stems made of titanium alloy (Ti-6Al-7Nb). The control stem (STD-SL-PLUS stem) underwent alumina grit blasting to reach the adequate roughness of 4-6 micron. | Device: SL-PLUS-Stem for total hip arthroplasty<br>* Patients undergoing primary total hip arthroplasty are randomly assigned (1:1) to receive either an uncemented NT-SL-PLUS Stem (Smith&Nephew Orthopaedics AG, Aarau, Switzerland) or a matching uncemented STD-SL-PLUS stem (Smith&Nephew Orthopaedics AG, Aarau, Switzerland) in a blinded fashion.<br>|
| Active Comparator: NT-SL-PLUS Stem<br>Rectangular SL straight stems made of titanium alloy (Ti-6Al-7Nb). The experimental stem (NT SL-PLUS) underwent alumina grit blasting to reach the adequate roughness of 4-6 micron. The surface of the NT SL-PLUS stem was thereafter additionally treated chemically by short-acid etching with HF and mechanically by dry ice blasting in order to loosen and remove the residual alumina particles up to 96% without changing the existing surface microtopography. | Device: SL-PLUS-Stem for total hip arthroplasty<br>* Patients undergoing primary total hip arthroplasty are randomly assigned (1:1) to receive either an uncemented NT-SL-PLUS Stem (Smith&Nephew Orthopaedics AG, Aarau, Switzerland) or a matching uncemented STD-SL-PLUS stem (Smith&Nephew Orthopaedics AG, Aarau, Switzerland) in a blinded fashion.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Baseline Bone mineral density by DEXA | Bone mineral density around the stem is measured as a surrogate for prosthesis in-growth by a dual-energy x-ray absorptiometry device (DEXA) (General Electric). | Measurements will be performed 7 days (baseline) after surgery | 
| Change from baseline Bone mineral density by DEXA at 3 months | Bone mineral density around the stem is measured as a surrogate for prosthesis in-growth by a dual-energy x-ray absorptiometry device (DEXA) (General Electric). | Measurements will be performed 3 months postoperatively | 
| Change from baseline Bone mineral density by DEXA at 6 months | Bone mineral density around the stem is measured as a surrogate for prosthesis in-growth by a dual-energy x-ray absorptiometry device (DEXA) (General Electric). | Measurements will be performed 6 months postoperatively | 
| Change from baseline Bone mineral density by DEXA at 12 months | Bone mineral density around the stem is measured as a surrogate for prosthesis in-growth by a dual-energy x-ray absorptiometry device (DEXA) (General Electric). | Measurements will be performed 12 months postoperatively | 
| Change from baseline Bone mineral density by DEXA at 24 months | Bone mineral density around the stem is measured as a surrogate for prosthesis in-growth by a dual-energy x-ray absorptiometry device (DEXA) (General Electric). | Measurements will be performed 24 months postoperatively | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rate of radiolucent lines on hip radiographs (AP and axial) at 12 months | Assessment of radiographs for radiolucent lines (RLs) around the stem. | Measurements will be performed at 12 months postoperatively. | 
| Rate of radiolucent lines on hip radiographs (AP and axial) at 24 months | Assessment of radiographs for radiolucent lines (RLs) around the stem. | Measurements will be performed at 24 months postoperatively. | 
| Rate of osteolysis on hip radiographs (AP and axial) at 12 months | Assessment of radiographs for osteolysis around the stem. | Measurements will be performed at 12 months postoperatively. | 
| Rate of osteolysis on hip radiographs (AP and axial) at 24 months | Assessment of radiographs for osteolysis around the stem. | Measurements will be performed at 24 months postoperatively. | 
| Rate of hypertrophies and atrophies on hip radiographs (AP and axial) at 12 months | Assessment of radiographs for hypertrophies and atrophies around the stem. | Measurements will be performed at 12 months postoperatively. | 
| Rate of hypertrophies and atrophies on hip radiographs (AP and axial) at 24 months. | Assessment of radiographs for hypertrophies and atrophies around the stem. | Measurements will be performed at 24 months postoperatively. | 
| Baseline WOMAC | For clinical scoring, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) will be assessed. | Measurements will be performed 1 month preoperatively. | 
| Change in WOMAC at 12 months | For clinical scoring, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) will be assessed. | Measurements will be performed 12 months postoperatively | 
| Change in WOMAC at 24 months | For clinical scoring, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) will be assessed. | Measurements will be performed 24 months postoperatively | 
| Baseline HHS | For clinical scoring, the Harris Hip Score (HHS) will be assessed. | Measurements will be performed 1 month preoperatively. | 
| Change in HHS at 12 months | For clinical scoring, the Harris Hip Score (HHS) will be assessed. | Measurements will be performed 12 months postoperatively | 
| Change in HHS at 24 months | For clinical scoring, the Harris Hip Score (HHS) will be assessed. | Measurements will be performed 24 months postoperatively | 
| Survival rates | THA survival rates and adverse events will be documented up to 24 months postoperatively. | Up to 24 months postoperatively. |