SMW Supplementum 193 - Swiss Medical Weekly

21 S SWiSS Med Wkly 2012;142(Suppl 193) · www.smw.ch Free communications
FM78
Total Hip Replacement in Patients with History
of Illicit Injecting Drug use
Karl Wieser, Patrick Zingg, Michael Betz, Georg Neubauer,
Claudio Dora
Uniklinik Balgrist
Introduction: Since the risk to cause and spread infection with
colonized strains is known to be multiplied by injection or inhalation
of drugs, total hip arthroplasty (THA) in patients with a history of illicit
drug use (IDU) is a concern. Our aim was to evaluate implant revision
rates in patients with a history of IDU undergoing THA.
Material and methods: A retrospective consecutive single series of
patients undergoing THA between January 1999 and December 2009
with history of IDU but declared and confirmed abstinence by patients
and their respective healthcare professionals was followed until death,
implant revision or for a minimum of 24 months.
Results: From 24 patients (27 THA) one (2 THA) left for a foreign
country and could not be traced, three (4 THA) died after a mean
of 24 months (range: 6–73) unrelated to surgery after an uneventful
course. From the remaining 20 patients (21 THA), 11 patients (11 THA)
had an uneventful course, without any clinical signs of infection and
perfect radiological appearance of the THA after a mean of 69 months
(range: 24–123). From the remaining 9 patients 8 THA were revised
and 2 THA are awaiting revision. Reason for revision was deep sepsis
in 8 and periprosthetic fracture in 2 patients, from which one
complicated with a postoperative deep infection. Cumulative ten year
implant revision rates were 49% (CI: 39–61%) for any reason and 43%
(CI: 31–55%) for septic reason. Five patients admitted recurrence of
IDU after THA. Abstinence of less than one year was more often
associated with IDU recurrence and both increased the risk of septic
implant failure (p = 0.023, p = 0.061).
Conclusion: A history of IDU is a major risk factor for septic failure.
Even after declared IDU abstinence, a 20% admitted recurrence rate
occurs and is associated with an even increased risk of septic
implant failure.
FM79
Risk Factors for aseptic loosening of Muller type
straight stems – A register-based analysis of
828 consecutive cases with a minimum follow-up of 16 years
Martin Clauss1 , Silke Pannhorst1 , Andre Butscher2 ,
Martin Lüem1 , Peter E. Ochsner1 , Thomas Ilchmann1 1 2 Kantonsspital Liestal; RMS Foundation
Even small design variables of the femoral stem may influence the
outcome of a hip arthroplasty. We performed a risk factor analysis for
aseptic loosening with special emphasis on design modifications of
cemented Müller-type straight stems. We investigated 828 total hip
replacements carried out with 4 different versions of cemented
Müller-type straight stems. These replacements were carried out at our
institution, and patients were followed prospectively in the in-house
register. All stems were operated in the same setup, using Sulfix-6
bone cement and a second-generation cementing technique.
Demographic and design-specific characteristics were analysed using
an adjusted Cox regression model. The 4 versions showed marked
differences in 15-year stem survival with aseptic loosening as the
endpoint: 93.9% (MSS CoNiCrMo), 83.0% (SL CoNiCrMo), 81.4%
(MSS Ti-6Al-7Nb) and 64.3% (SL Ti-6Al-7Nb). The Cox regression
analysis showed a relative risk (RR) of 3.811 for aseptic loosening for
stems made out of Ti-6Al-7Nb. The RR for aseptic loosening of the SL
design was 2.129. Overall, the risk ratio for aseptic loosening of the
stem increased to 7.486 (95% CI: 3.758–14.912) when comparing the
most and the least successful designs (MSS CoNiCrMo vs. SL
Ti-6Al-7Nb). Cemented Müller-type straight stems should be made out
of a material with high flexural strength (e.g. CoNiCrMo). The surface
finish should be polished (Ra