Diagnostic Accuracy of Synovial Biopsy for Implant-Related Shoulder Infections

To assess the diagnostic accuracy of percutaneous synovial biopsy (test procedure) for detection of implant-related intraarticular shoulder infections (IISI), in comparison to direct macroscopic synovial biopsy, from either arthroscopic or open procedures (the reference standard).

To address the primary objective, standard diagnostic accuracy statistics (sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio) will be derived, comparing lab results from percutaneous synovial biopsy specimen collection to those of the reference standard test (open/arthroscopic).

Using a visual analog scale, participants will rank their pain level 24-hours after the synovial biopsy. 0 indicating no pain, and 10 indicating the worst pain. A higher score indicates a worse outcome.

Participants will be monitored for re-infection after their revision surgery for 5-years. Higher incidences of infection indicate a worse outcome.

The Constant Score reflects an overall clinical functional assessment. This instrument is based on a 100-point scoring system. Subjective findings (pain, activities of daily living, and working in different positions) make up a total of 35 points. Objective measurements make up the remaining 65 points.The test is divided into four sub-categories: (1) pain is measured using 4 likert levels (15 points maximum), where a higher score indicates a better outcome; activities of daily living are measured using a likert scale, where a higher number indicates better outcomes (20 points maximum); mobility is measured by an assessor, and rated using a likert scale where a higher score indicates better outcomes (40 points maximum); finally, strength is measured by an assessor where 1 point is given per 0.5kg of force (maximum 25 points), a higher score indicates better outcomes. All categories are added together, and a total score out of 100 is given (higher score indicates better outcome).

The Western Ontario Osteoarthritis of the Shoulder Index (WOOS) is a disease specific evaluation, proven to be an accurate and valid assessment of function after shoulder replacement. The WOOS is a patient-reported measure, 19-question survey. Each question is measured using a visual analog scale rated from 0-100, where higher scores mean better outcome.

The ASES is a shoulder specific assessment divided into two sections: pain and activities of daily living (ADL). Pain is recorded on a visual analogue scale (0-10), lower scores indicate better outcomes. There are 10 activities of daily living questions, each are recorded on a 4 level likert scale (0-3), which a higher score indicates a better outcome. The overall score is an equal weight of the two sections and produces a score out of 100. The higher the score, the better the outcome.

The EQ-5D-5L quality of life questionnaire is a brief, easy to administer generic health status questionnaire, consisting of five dimensions (mobility, self-care, usual activities, pain/discomfort, anxiety/depression) each of which can take one of five responses (each question rated 1-5), lower scores indicate better outcome. It also includes a visual analogue scale for recording an individual's rating of their current health-related quality of life (scale 0 to 100), where a higher score indicates a better outcome.