Influence of canal preparation depth on the incidence of femoral medullary infarction with Zurich Cementless Canine Total Hip arthroplasty.

Objective: To determine the incidence of femoral medullary infarction after modifying the depth of femoral reaming and filing when performing total hip replacement (THR) using the Zurich Cementless Total Hip Replacement system (ZCTHR).

Study Design: Case series.

Animals: Dogs (n=31) that had ZCTHR (34).

Methods: Thirty-one dogs (34 THR) had ZCTHR (May 2003-September 2006) and with >1 year radiographic (craniocaudal, mediolateral views) follow-up after THR were evaluated for the presence of femoral medullary infarcts. Incidence was compared with a previous study performed before the technique modification.

Results: Femoral medullary infarction occurred in 1 femur (2.9%; dog <18 months at THR) compared with 19.5% before the technique change, a significant decrease (P<.001).

Conclusion: Limiting the depth of reaming and filing of the medullary canal resulted in a significant decrease in the incidence of femoral medullary infarction.

Clinical Relevance: Depth of reaming and filing the medullary canal should be limited when performing THR using the ZCTHR.