Partial revision of a dislocated periprosthetic tibial fracture after total ankle replacement with a stemmed implant and plate fixation: A case report

INTRODUCTION

Total ankle arthroplasty (TAR) procedures have become more reliable and incidence is increasing. A growing number of postoperative complications can be expected and should be correctly addressed.

PRESENTATION OF CASE

A 43-year-old woman suffering from severe ankle osteoarthritis underwent TAR (Stryker's Infinity with Prophecy alignment guides, uncemented tibial component and cemented talus component). After a fall, one month after the surgery, she presented with a fracture of the medial malleolus and an anterior periprosthetic fracture of the tibia, with anterior dislocation of the tibial prosthetic component. Fracture fixation and partial revision surgery was planned using the same anterior surgical access. To restore length, rotation and joint articulation, the medial malleolus was first reduced and synthesized with a plate and 6 screws through additional minimally invasive medial ankle incisions. Once the medial malleolus was stabilized, the already mobilized tibial component was removed. Freehand cuts under fluoroscopic guidance on the anterior surface of the tibia were performed. After a final check with a trial component, a Stryker's Inbone II stem, which matched the previously inserted talar component, was implanted and partially cemented to fill the remaining bone gaps.

DISCUSSION

Only few case reports of periprosthetic ankle fractures exist, and none of them were similar to ours. There are no published precedents for this revision approach from a stemless to a stemmed tibial implant without changing the talar implant.

CONCLUSION

Partial revision after a complex periprosthetic fracture results in a satisfactory outcome if surgery is performed in specialized centers.

Acute Prosthetic Joint Infections with Poor Outcome Caused by Staphylococcus Aureus Strains Producing the Panton-Valentine Leukocidin

The aim of this study was to investigate whether the presence of Staphylococcus aureus (SA) producing the Panton-Valentine leukocidin (PVL) affects the outcome of Prosthetic Joint Infection (PJI). Patients with acute and chronic PJI sustained by SA were prospectively enrolled at the orthopedic unit of "Casa di Cura Santa Maria Maddalena", from January 2019 to October 2021. PJI diagnosis was reached according to the diagnostic criteria of the International Consensus Meeting on PJI of Philadelphia. Synovial fluid obtained via joint aspirations was collected in order to isolate SA. The detection of PVL was performed via real-time quantitative PCR (RT-qPCR). The outcome assessment was performed using the criteria of the Delphi-based International Multidisciplinary Consensus. Twelve cases of PJI caused by SA were included. Nine (75%) cases were acute PJI treated using debridement, antibiotic and implant retention (DAIR); the remaining three (25%) were chronic PJI treated using two-stage (n = 2) and one-stage revision (n = 1), respectively. The SA strains that tested positive for PVL genes were 5/12 (41.6%,). Treatment failure was documented in three cases of acute PJI treated using DAIR, all supported by SA-PVL strains (p < 0.045). The remaining two cases were chronic PJI treated with a revision arthroplasty (one and two stage, respectively), with a 100% eradication rate in a medium follow-up of 24 months. Although a small case series, our study showed a 100% failure rate in acute PJI, probably caused by SA PVL-producing strains treated conservatively (p < 0.04). In this setting, toxin research should guide radical surgical treatment and targeted antibiotic therapy.

The First Case of a Drug-Resistant Pasteurella multocida Prosthetic Knee Infection Successfully Treated With Debridement, Antibiotics, and Implant Retention

Pasteurella multocida, a zoonotic infectious organism, has most often been described in patients after an animal bite. It can cause a variety of infections ranging from superficial skin infections to more serious systemic infections, such as sepsis and meningitis. P. multocida is a rare but well-recognized cause of prosthetic joint infections. Here, we report the first implant-associated infection caused by drug-resistant (penicillin, ampicillin, amoxicillin/clavulanic acid) P. multocida, which was cured with targeted antimicrobial treatment and debridement, exchange of mobile parts, and retention of the prosthesis. Patients undergoing arthroplasty should be informed of the risks of close contact with pets, especially in light of the worrying phenomena of drug resistance spreading among animals due to the addition of antibiotics in animal feed.