title: Stable Fixation of a Cementless, Proximally Coated, Double Wedged, Double Tapered Femoral Stem in Total Hip Arthroplasty: A 5-Year Radiostereometric Analysis.
abstract: The objective of this 5-year prospective study of 51 hips was to assess migration of a cementless tapered femoral stem using radiostereometric analysis (RSA), plain radiographs (radiolucencies), and patient-reported outcome measures (PROMs).
  
  
  
  Forty-seven patients (51 hips) agreed to participate in this prospective RSA study. All patients received a Taperloc stem. Tantalum beads were inserted into the femoral bone surrounding the stem to measure migration using RSA. RSA films, plain radiograph, and PROM follow-up were obtained immediately after surgery, 6 months, 1, 2, 3, and 5 years after surgery.
  
  
  
  The median (interquartile range) subsidence was 0.03 mm (-0.23 to 0.06) at 5 years, with no significant differences over time. Four outlier stems had >1.5 mm of subsidence by 1 year. No stem showed radiolucencies in more than 3 zones during the 5 years. All PROMs remained favorable at 5 years, suggesting an excellent outcome. There were no stems revised for mechanical loosening; 1 stem was revised for an infection.
  
  
  
  After initial settling, the cementless tapered femoral stems in our series were stable. The 4 outlier stems with >1.5 mm of subsidence by 1 year remain stable at 5 years. RSA was the most sensitive method of detection for stems at greater risk for potential future failure. This report adds contributions to the positive results associated with this type of fixation. The results at 5 years showed excellent midterm survivorship in this cohort with a cementless tapered femoral component.
authors.affiliation: Department of Orthopaedics, Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Audrey K
authors.initials: AK
authors.lastname: Nebergall
authors.affiliation: Department of Orthopaedics, Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, Massachusetts; Department of Orthopaedics, Institute of Clinical Sciences at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Ola
authors.initials: O
authors.lastname: Rolfson
authors.affiliation: Department of Orthopaedics, Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Harry E
authors.initials: HE
authors.lastname: Rubash
authors.affiliation: Department of Orthopaedics, Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Henrik
authors.initials: H
authors.lastname: Malchau
authors.affiliation: Department of Orthopaedics, Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, Massachusetts; Department of Orthopedics, Copenhagen University Hvidovre Hospital, Hvidovre, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Troelsen
authors.affiliation: Department of Orthopaedics, Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Meridith E
authors.initials: ME
authors.lastname: Greene
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D005260:Female; D005269:Femur / Q000601:surgery*; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006652:Histological Techniques; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D059869:Radiostereometric Analysis; D012086:Reoperation; D057566:Self Report; D012720:Severity of Illness Index; D013635:Tantalum; D016896:Treatment Outcome
chemical_list: D013635:Tantalum
keywords: cementless arthroplasty; patient-reported outcome measures; radiolucencies; radiostereometric analysis; total hip arthroplasty