Risk of infection after double locking plate and screw fixation of tibial plateau leveling osteotomies in dogs weighing greater than 50 kilograms.

Objective: To compare surgical site infection (SSI) rates after double locking plate and screw fixation (DLP), standard locking plate and screw fixation (LP), and conventional nonlocking plate and screw fixation (NLP) in dogs weighing >50 kg undergoing tibial plateau leveling osteotomy (TPLO).

Study Design: Retrospective study (January 2003-October 2017).

Animals: Two hundred seventy-five dogs weighing >50 kg with cranial cruciate ligament disease treated with TPLO.

Methods: Medical records of dogs weighing >50 kg that underwent TPLO by DLP, LP, and NLP with a minimum follow-up period of 12 months were included. Data collected included signalment, details of any concurrent surgical procedure, type of implant used, use of postoperative antibiotic therapy, occurrence of perioperative complications, and presence of postoperative infection. The probability, risk difference, and relative risk of SSI were estimated for each fixation with a marginal model.

Results: Nonlocking plate and screw fixation was used in 114 (41.5%) dogs, LP was used in 128 (46.5%) dogs, and DLP was used in 33 (12%) dogs. Surgical site infection was diagnosed in 48 of 275 (17.5%) dogs. Postoperative antibiotic therapy was used in 74 (64.9%) dogs, 62 (48.4%) dogs, and 32 (97.0%) dogs in the NLP, LP, and DLP groups, respectively. Dogs with NLP, LP, and DLP had postoperative infection rates of 24.5%, 13.3%, and 9.1%, respectively. There were no risk differences for the three groups (Holm-adjusted P > .05).

Conclusion: No difference in infection rates was detected between DLP, LP, or NLP for TPLO in these dogs weighing >50 kg.

Clinical Significance: Fixation of TPLO with DLP in dogs weighing >50 kg does not seem to increase the risk of SSI compared with LP and NLP.