Fracture of the Neck of the Femur After Surface Arthroplasty of the Hip
The Journal of Bone and Joint
Surgery (American) 86:1874-1877 (2004)
© 2004
The Journal of Bone and Joint Surgery, Inc.
Harlan C. Amstutz, MD1,
Pat A. Campbell, PhD1 and
Michel J. Le Duff, MA1
1 Joint Replacement
Institute at Orthopaedic Hospital, 2400 South Flower
Street, Los Angeles, CA 90007.
Investigation performed at the
Joint Replacement Institute at Orthopaedic
Hospital, Los Angeles, California
In support of their research or preparation of this
manuscript, one or more of the authors
received grants or outside funding from
The Los Angeles Orthopaedic Hospital Foundation, the
William G. McGowan Charitable Fund, Inc.,
and Wright Medical Technology. In
addition, one or more of the authors received
payments or other benefits or a
commitment or agreement to provide such
benefits from a commercial entity (Wright Medical
Technology). Also, a commercial entity
(Wright Medical Technology) paid or
directed, or agreed to pay or direct, benefits to a
research fund, foundation, educational
institution, or other charitable or
non-profit organization with which the authors are
affiliated or associated.
Background: There are two main modes of failure of the femur
following surface arthroplasty of the
hip: femoral neck fracture and aseptic loosening.
The purpose of the present study was to
present our experience with femoral neck
fractures that occurred after metal-on-metal
hybrid surface arthroplasty and to assess
their cause.
Methods: A series of 600 metal-on-metal
surface arthroplasties was performed
between late 1996 and early 2003. Failures that
occurred during this period were assessed
radiographically and with implant
retrieval analysis to determine their cause.
Results: Five femoral neck fractures
occurred in this series (prevalence,
0.83%). Four of the five fractures occurred at the
component-neck junction within the first
five months (average, three months) after surgery.
All five fractures were associated with a
traumatic episode, but all five also were
associated with structural and/or technical
risk factors, which we believe weakened the
femoral neck. The most important
technical deficiency that contributed to three
of the five fractures was the failure to cover
all of the reamed bone with the
component.
Conclusions: It is important to avoid or
at least minimize notching of the femoral
neck by performing the cylindrical reaming at the
recommended angle of 140° and to stop reaming
before the reamer touches the lateral
cortex. Osteophytes should be removed
judiciously only if there is notable impingement
when the hip is flexed to 90° and
internally rotated. We believe that
understanding the factors that contribute to femoral
neck fracture after surface arthroplasty
may reduce the prevalence of this mode of
failure.
Level of Evidence: Therapeutic study,
Level IV (case series [no, or
historical, control group]). See Instructions to
Authors for a complete description of
levels of evidence.
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