Mechanical complications with one hundred and thirty eight (antibiotic-laden) cement spacers in the treatment of periprosthetic infection after total hip arthroplasty.

PURPOSE: Periprosthetic infection after total hip arthroplasty is a devastating complication. A two-stage protocol with the temporary insertion of an antibiotic-laden cement spacer is the gold standard treatment for chronic infections (Clinics (Sao Paulo) 62:99-108, 2007; Clin Orthop Relat Res 427:37-46, 2004; J Arthroplast 14:175-181, 1999; Clin Orthop Relat Res 467:1848-1858, 2009; J Arthroplast 20:874-879, 2005; J Arthroplast 24: 607-613, 2009; Clin Orthop Relat Res 469:1009-1015, 2011; Hip Int 20:26-33, 2010; J Arthroplast 24:1051-1060, 2009; J Bone Joint Surg Br 91:44-51, 2009). Some authors, however (Int J Med Sci 6(5):265-73, 2009), report mechanical complication rates with spacers in excess of 50%.Therefore, the aim of this study is to determine (1) the mechanical complications associated with enclosed articulating partial load-bearing spacers when treating periprosthetic hip infections and (2) possible factors of influence.

METHODS: Between 2000 and 2011, 138 patients received an antibiotic-laden cement spacer as part of a two-stage protocol. The overall frequency of complications (spacer fracture, dislocation, femoral fracture with enclosed spacer, spacer fracture with dislocation, protusion into the pelvis) was recorded. Potential influencing factors ('mould spacer' vs. handmade spacer, Steinmann pins as an endoskeleton, addition of vancomycin into the spacer) were analysed.

RESULTS: The mean age at the time of the first stage operation was 69.3 ± 10.5 years. Overall, 27 of 138 patients suffered one of the above-mentioned complications (19.6%). Spacer fracture occurred in 12 cases (8.7%) and dislocation in another 12 (8.7%). There was also one periprosthetic femoral fracture with a spacer in situ, one dislocation with a simultaneous spacer fracture, and one protrusion into the pelvis (0.7% each).

CONCLUSIONS: Our data revealed an overall complication rate of 13.2% with a mould spacer enclosing a Steinman pin. The mechanical complication rate of over 50% reported by some authors cannot be confirmed. As a consequence, we recommend using a mould spacer with an enclosed Steinman pin as an endoskeleton to minimize the complication rate.