Introduction
Two of the most common complications of joint arthroplasty surgery are aseptic and septic loosening. While aseptic loosening has a well-established treatment protocol, and diagnosis is quite straightforward, bacterial colonization of the implants is associated with a more difficult diagnosis and treatment, more surgeries, and higher morbidity for the patient. Accurate diagnosis is essential in choosing the right treatment plan. The aim of the current study was to assess the current diagnostic methods for periprosthetic joint infection and the influence of clinical signs like sinus tract on the treatment algorithm and outcomes of the patients. We wanted to highlight that sinus tract is still one of the major criteria in periprosthetic joint infection diagnosis and its presence increases the probability of choosing the right therapeutic option.
Materials and methods
During the three-year period of the study, we included 48 cases of patients who presented in our hospital with pain around their hip or knee prostheses. Inclusion criteria were patients diagnosed with septic or aseptic loosening of the prosthesis that required surgical revision of the implant in one stage or two stages. We excluded patients who did not require surgery yet or had major contraindications for revision surgery, patients who refused surgery, acute periprosthetic joint infections (less than 1 month since implantation), or extrinsic mechanical complications of the prosthesis like periprosthetic fractures, implant dislocations.
Results
Out of 48 patients, 25 underwent one-stage revision and 23 underwent two-stage revision surgery (septic revision). In the subgroup of two-stage revision, 18 patients (78.2%) presented a sinus tract communicating with the prosthesis, this clinical sign being a major characteristic of the subgroup. We managed to successfully identify 21 out of 23 cases (91.3%) of periprosthetic joint infections prior to or during the surgery. In the two cases in which we misdiagnosed the infection, the sinus tract or a positive bacterial culture was absent prior to surgery, in addition to other clinical or paraclinical findings indicating only a small probability of periprosthetic joint infection, influenced the attending medical doctor's therapeutic decision. In these particular cases of culture-negative periprosthetic joint infections, the outcome was poor, with patients needing additional surgeries in order to eradicate the infection.
Discussion
When present, a clear sign of periprosthetic joint infection, such as a sinus tract, facilitates the diagnostic protocol and allows the medical staff to initiate the appropriate treatment earlier. In the absence of such obvious signs, differential diagnosis remains difficult, and we should consider the future development of faster, cheaper, and more accurate tests for periprosthetic joint infection diagnosis, especially for chronic low-grade infections that could be easily misdiagnosed.
