, Volume 471, Issue 2, pp 454-462
Date: 05 Sep 2012

High Survival of Modular Tapered Stems for Proximal Femoral Bone Defects at 5 to 10 Years Followup

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Abstract

Background

Currently, the two most commonly used options for the revision of femoral components in North America are: cylindrical, nonmodular, cobalt-chromium stems and tapered, fluted, modular, titanium (TFMT) stems. Previous reports have cited high failure rates with cylindrical cobalt chrome stems in large femoral defects but the longer term survival of the fluted stems is unknown.

Questions/Purposes

We examined the 5- to 10-year survival of TFMT stems implanted for severe femoral defects.

Methods

We reviewed all 65 patients with severe proximal bone defects revised with the TMFT stem between January 2000 and 2006. Ten were lost to followup and seven were dead, leaving 48 patients for followup at 5 to 10 years (mean, 84 months; range, 60–120 months). All patients completed five quality-of-life (QOL) questionnaires. Radiographs were evaluated for loosening, subsidence, and preservation of proximal host bone stock.

Results

Implant survivorship was 90%. No patient underwent revision for either subsidence or loosening. Subsidence occurred in seven patients (average, 12.3 mm) but all achieved secondary stability. Five patients underwent revision as a result of fracture of the stem and all had the original standard stem design, which has since been modified. All five implant fractures occurred at the modular stem junction. Mean QOL outcomes were: WOMAC = 81 (pain), Oxford = 75, SF-12 = 54 (mental) and 38 (physical), UCLA Activity = 4, and satisfaction overall = 73.

Conclusions

Midterm survivorship of modular titanium stems in large femoral defects is high; however, ongoing surveillance of stem junctional fatigue life is required.

Level of Evidence

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

One of the authors (CPD) certifies that he has or may receive payments or benefits, in any one year, an amount in excess of $10,000, from a commercial entity (Zimmer, Inc, Warsaw, IN, USA) related to this work. One of the authors (BAM) certifies that he has or may receive payments or benefits, in any one year, an amount in excess of $10,000, from a commercial entity (Zimmer, Inc) related to this work. One of the authors (DSG) certifies that he has or may receive payments or benefits, in any one year, an amount in excess of $10,000, from a commercial entity (Zimmer, Inc) related to this work. The institution of one or more the authors (APVH, CPD, BAM, NVG, DSG) has received funding from Zimmer Inc.
All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request.
Clinical Orthopaedics and Related Research neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDA-approval status, of any drug or device prior to clinical use.
Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained.