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Completed

NCT Number: NCT02648152

POLARSTEM Cementless Hip Stem

Multicenter observational study to validate that the POLARSTEM™ is a state-of-the-art implant in terms of radiographic, clinical performance and long-term survivorship.

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Key information

Conditions

Osteoarthritis Arthritis Joint Diseases Musculoskeletal Diseases Rheumatic Diseases

Age range

18 year–75 year

Sex eligibility

All sexes

Study type

Observational

Primary location

St. Elisabeth Hospital, Orthopedics and Rheumatology, Bochum, Germany

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About this study

The goal of this multicenter clinical observation is to validate short-, mid-, and long-term outcome (efficacy and safety) of the POLARSTEM™.

Efficacy evaluations:

  • Evaluation of function, range of motion (ROM) and pain as assessed by Harris Hip Score, Hip disability and osteoarthritis outcome score (HOOS) [7, 8], an extension of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).
  • Radiographic changes as defined by radiolucent lines, osteolysis, hypo- and hypertrophy, implant loosening or migration

Safety evaluations:

  • Intra- and perioperative device-related adverse events (AE) and complications up to discharge
  • Postoperative AE up to 10 years

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patient has no general medical contraindication to surgery
  • Informed consent to participate in the MCO signed by the patient
  • Routine radiographic assessment is possible
  • Patient is likely to comply with study follow-up requirements
  • Primary total hip replacement (THR) to the affected side, unilateral or bilateral

Exclusion criteria

  • Previously failed endoprosthesis and /or THR components in relevant hip
  • History of infection in the affected joint; systemic infections
  • Grossly insufficient femoral or acetabular bone stock in the involved hip
  • Charcot joint disease or other severe neurosensory deficit
  • Severe spinal disorders
  • Age of patient at date of surgery > 75 years
  • High comorbidity
  • Cemented acetabular cup

Treatment and study plan

Total hip arthroplasty

Device

Total Hip Arthroplasty using Cementless version of the POLARSTEM

Primary outcomes

  1. Kaplan-Meier Estimate: Overall Survivorship of POLARSTEM

    Time frame: Pre-operatively, 3 months, 12 months, 36 months, 60 months, and 120 months

    Overall survivorship of the Cementless Version of the POLARSTEM pre-operatively, 3 months, 12 months, 12 months, 36 months, 60 months, and 120 months by Kaplan-Meier estimate with overall hip survivorship defined as the time between date of treatment and date of revision for any reason.

Secondary outcomes

  1. Harris Hip Score (HHS)

    Time frame: Pre-operative, 3 Months, 12 Months, 36 Months, 60 Months, 120 months

    The HHS measured function, range of motion (ROM), and pain sub-scores that are combined to indicate total dysfunction on a numerical scale from 0 to 100, with a higher score indicating less dysfunction (i.e., a better outcome). Reported scores for the HHS utilized the following grading:

    • <70 = poor
    • 70 to 80 = fair
    • 80 to 90 = good
    • 90 to 100 = excellent

  2. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC): Pain Subscale

    Time frame: Pre-operative, 3 Months, 12 Months, 36 Months, 60 Months, 120 Months

    WOMAC Pain subscale is a subset of the Hip Disability and Osteoarthritis Outcome Score (HOOS) with a range of 0 to 20. Higher WOMAC scores indicate worse pain (i.e., worse outcome) and lower scores indicate less pain (i.e., a better outcome).

  3. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC): Stiffness Subscale

    Time frame: Pre-operative, 3 Months, 12 Months, 36 Months, 60 Months, 120 Months

    WOMAC Stiffness subscale is a subset of the Hip Disability and Osteoarthritis Outcome Score (HOOS) with a range from 0 to 8 with a higher score indicating a worse outcome and a low score indicating a better outcome.

  4. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC): Physical Function Subscale

    Time frame: Pre-operative, 3 Months, 12 Months, 36 Months, 60 Months, 120 Months

    WOMAC Physical Function subscale is a subset of the Hip Disability and Osteoarthritis Outcome Score (HOOS) with a range from 0 to 68 with a higher score indicating a worse outcome and a low score indicating a better outcome.

  5. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC): Total Score

    Time frame: Pre-operative, 3 Months, 12 Months, 36 Months, 60 Months, 120 Months

    WOMAC total score combines Stiffness, Pain, and Physical Function subscales of the Hip Disability and Osteoarthritis Outcome Score (HOOS) into a range from 0 to 96 with a higher score indicating a worse outcome and a lower score indicating a better outcome.

  6. Radiological: Radiolucent Lines

    Time frame: 3 months, 12 months, 36 months, 60 months, 120 months

    Number of hips identified with radiographic findings of radiolucent lines present (Yes/No) in femoral zones 1 to 14. Radiolucent lines indicated seams of 0 millimeters to 2 millimeters or greater.

  7. Radiological: Osteolysis

    Time frame: 3 months, 12 months, 36 months, 60 months, 120 months

    Number of hips identified with radiographic findings of osteolysis present (Yes/No) in femoral zones 1 to 14.

  8. Radiological: Atrophy

    Time frame: 3 months, 12 months, 36 months, 60 months, 120 months

    Number of hips identified with radiographic findings for atrophy in femoral zones 1 to 14 indicated as:

    • None
    • Mild
    • Moderate
    • Severe
    • Missing

  9. Radiological: Hypertrophy

    Time frame: 3 months, 12 months, 36 months, 60 months, 120 months

    Number of hips identified with radiographic findings for hypertrophy in femoral zones 1 to 14 indicated as:

    • None
    • Mild
    • Moderate
    • Severe
    • Missing

  10. Radiological: Loosening of the Implant or Migration

    Time frame: 3 months, 12 months, 36 months, 60 months, 120 months

    Number of hips identified with radiographic findings associated with loosening of the implant or migration were indicated as:

    • Integration not assessable
    • Indifferent, bone unchanged
    • Osteointegration, integration
    • Bone loss
    • Signs of loosening
    • Revision indicated

Sponsors and collaborators

Lead sponsor

Smith & Nephew, Inc.

Industry

Registry information

Official study title

Multicenter Clinical Observation Using the Cementless Version of the POLARSTEM

Acronym: POLARSTEM

Important dates

Study start
2009
Primary completion
2020
Study completion
2020
First posted
Jan 6, 2016
Registry last updated
Jan 21, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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