Experimental reproduction of periprosthetic joint infection: Developing a representative animal model

Infection after arthroplasty (prosthetic joint infection; PJI) is a devastating complication that can lead to functional loss of the affected limb. The purpose of the present study is to develop an animal model of PJI using a three-dimensional printed species-specific implant, which is a step forward for future research to develop new therapeutic strategies.

Fifteen New Zealand White rabbits were employed to reproduce PJI by intra-articular inoculation of 10 ⁵ cfu/ml of Staphylococcus aureus ATCC® 29213. Three-dimensional printing technology was used to design a species-specific four-millimeter-thick implant maintaining the anatomical irregularities of the tibial-articular surface. Response to bacterial inoculation was monitored by clinical (weight and temperature), hematological (leukocyte, lymphocyte and platelet counts) and biochemical (erythrocyte sedimentation rate) analyses at the time of inoculation and seven days thereafter, when microbiological samples for culture were also taken.

All animals recovered from surgery and all displayed full weight-bearing four days postoperatively. Fourteen of the 15 tested animals (93.3%) presented positive microbiological cultures. A statistically significant increase was found in the number of platelets and leukocytes, as well as a significant decrease in the percentage of lymphocytes, with P = 0.0001 in all cases.

An experimental model faithfully reproducing the periprosthetic infection environment and achieving a high rate of infection has been designed. The use of three-dimensional printed species-specific implants allows rapid postoperative recovery of animals and the development of a stable biofilm. These characteristics make it an interesting model to study its pathogenesis and possible therapeutic strategies.