Survey (Systematic Review)

Clinical Orthopaedics and Related Research®

, Volume 471, Issue 11, pp 3572-3580

First online:

Do Monoblock Cups Improve Survivorship, Decrease Wear, or Reduce Osteolysis in Uncemented Total Hip Arthroplasty?

  • Jelle J. HalmaAffiliated withClinical Orthopedic Research Center–midden Nederland (CORC-mN), Department of Orthopaedics, Diakonessenhuis Hospital Email author 
  • , H. Charles VogelyAffiliated withDepartment of Orthopaedics, University Medical Center Utrecht
  • , Wouter J. DhertAffiliated withDepartment of Orthopaedics, University Medical Center Utrecht
  • , Steven M. Van GaalenAffiliated withClinical Orthopedic Research Center–midden Nederland (CORC-mN), Department of Orthopaedics, Diakonessenhuis Hospital
  • , Arthur de GastAffiliated withClinical Orthopedic Research Center–midden Nederland (CORC-mN), Department of Orthopaedics, Diakonessenhuis Hospital

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Abstract

Background

Monoblock acetabular components used in uncemented total hip arthroplasty (THA) have certain mechanical characteristics that potentially reduce acetabular osteolysis and polyethylene wear. However, the degree to which they achieve this goal is not well documented.

Questions/purposes

The purpose of this study was to use a systematic review of controlled trials to test the hypothesis that monoblock cups have superior (1) polyethylene wear rate; (2) frequency of cup migration; (3) frequency of acetabular osteolysis; and (4) frequency of aseptic loosening compared with modular components used in uncemented THA.

Methods

A systematic search was conducted in the Medline, Embase, and Cochrane electronic databases to assemble all controlled trials comparing monoblock with modular uncemented acetabular components in primary THA. Included studies were considered “best evidence” if the quality score was either ≥ 50% on the Cochrane Back Review Group checklist or ≥ 75% the Newcastle-Ottawa quality assessment scale. A total of seven publications met our inclusion criteria.

Results

Best evidence analysis showed no difference in polyethylene wear rate, the frequency of cup migration, and aseptic loosening between monoblock and modular acetabular components. No convincing evidence was found for the claim that lower frequencies of acetabular osteolysis are observed with the use of monoblock cups compared with modular uncemented cups.

Conclusions

The purported benefits of monoblock cups were not substantiated by this systematic review of controlled studies in that polyethylene wear rates and frequencies of cup failure and acetabular osteolysis were similar to those observed with modular implants. Other factors should therefore drive implant selection in cementless THA.

Level of Evidence

Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.