The New Generation of Orthopedic Tests – Prosthetic Joint Infection Diagnosis in 15 Minutes


Prosthetic joint infection (PJI) has been identified as the most prevalent cause of failure after hip arthroplasty and knee replacement.

PJI is definitely a major difficulty of joint replacement surgery that necessitates longer hospitalization and re-operations as well as a considerable financial burden. Therefore a quick and accurate diagnosis has critical importance both for the patient and the surgeon.

In this article, we have collected some of the most typical errors and misconceptions in testing and ruling out PJI that can jeopardize treatment success. In addition, we introduce LyfstoneⓇCalprotectin, one of the most innovative and effective products for diagnosing PJI.

Common errors of traditional orthopaedic tests and diagnoses

1. Ineffective methods to rule out PJI

Because of their ease of use and rapid turnaround times, surgeons routinely report employing C-reactive protein (CRP) and erythrocyte sedimentation rates (ESRs) as first-line testing in suspected PJI.

CRP and ESR, however, are inflammatory indicators with poor sensitivity: levels within the normal range do not rule out the infection.

2. Diagnostic lag

In any patient who has prolonged wound leakage or a heated, swollen, or painful joint, the PJI should be ruled out as soon as possible. Unfortunately, it is usual to prolong the diagnoses by taking a “wait and see” strategy, wasting crucial time as the efficacy of antibiotics, debridement, and implant retention (DAIR) worsen with surgical postponement.

In addition, waiting for the results of traditional orthopaedic tests also wastes a lot of valuable time (hours or even days) for both the patient and the attending surgeon.

3. Ignoring distant infection origins

After perioperative contamination, hematogenous dissemination from a distant infectious focus onto the prosthesis by bacterial filtration during bacteremia is the second most prevalent aetiology.

If inflammatory biomarker levels do not reduce consistently after starting PJI therapy, or if symptoms emerge rapidly after a prolonged pain-free time following the first implantation, persistent sources of infection should be addressed.

4. Insufficient periprosthetic tissue samples for bacterial culture

A tissue sample for culture is one of the most often utilized intra-operative orthopaedic tests to diagnose PJI. The Infectious Diseases Society of America (IDSA) recommends sending at least three periprosthetic intraoperative tissue samples for aerobic and anaerobic culture, ideally five or six.

Recent research indicated that utilizing five or more tissue samples did not increase diagnostic accuracy and suggested using three periprosthetic tissue samples in blood culture bottles (BCBS) or four samples in traditional culture.

Fortunately, there is an innovative solution for ruling out PJI that helps to avoid the above errors while shortening and making the diagnosis more precise.

Introducing LyfstoneⓇ

LyfstoneⓇorthopaedic test is a novel diagnostic tool that measures the level of calprotectin in the patient’s synovial fluid. Calprotectin levels have been found to be higher in acute and chronic prosthetic joint infections. LyfstoneⓇ allows surgeons to rule out PJI after 15 minutes, on the spot, and in the presence of the patient. This saves a significant amount of time, which is critical in the case of prosthetic joint treatment. 

Traditional blood cell orthopaedic tests can only indicate that there is an infection in the body, but not where it is. The sample for the LyfstoneⓇ Calprotectin orthopaedic test is obtained directly from the joint fluid, allowing the surgeon to detect the area of the suspected infection correctly.

Thanks to its easy sample setup, LyfstoneⓇ can be used at any stage of care, from consultation through pre-op and post-op.

How to use LyfstoneⓇorthopaedic test?

LyfstoneⓇorthopaedic test can be used by the following 4 simple steps:

  1. Collect a sample of synovial fluid from the patient. The test kit contains a buffer tube that helps measure the correct amount of the joint fluid sample.
  2. Dilute the sample using the buffer tube. 
  3. Place the sample on the test.
  4. The test result can be assessed within 15 minutes, using the LyfstoneⓇ Reader app which is compatible with both iOS and Android smartphones.


As can be seen from the examples above, traditional orthopaedic tests and diagnostic methods in

ruling out PJI might lead to various errors that can delay the treatment the patient needs. LyftstoneⓇ test offers an innovative and functional solution to this situation.

LyfstoneⓇ orthopaedic test helps surgeons and traumatologists to make a fast and accurate diagnosis instead of waiting hours to get the results from external laboratories. The straightforward sample setup enables its usage at any point of care.