Diagnostic Accuracy in the Clinical Examination for Identifying a Triangular Fibrocartilage Complex Injury

Abstract

TFCC injuries are a common cause of ulnar wrist pain, which can impact patients’ functional ability and quality of life. In Aotearoa, New Zealand patients with musculoskeletal injuries, such as wrist injuries are often initially assessed and treated by hand therapists and physiotherapists. As part of assessment and diagnosis procedures, clinical diagnostic tests are routinely used to either confirm or exclude suspicions. Despite their widespread use, the supporting literature is not favourable in regards to their usefulness. A systematic review of the literature highlights the high reliability of diagnostic tests for TFCC injuries. However, their ability to either exclude or confirm TFCC injuries is limited, and there is a lack of a conclusive singular diagnostic test that can accurately do both. To date, there has not been any study that has investigated both the reliability and diagnostic accuracy of multiple TFCC diagnostic tests or investigated a combination of clinical factors that could improve predictability of TFCC injuries.

A prospective pilot study was undertaken. Twenty-three participants were recruited from Auckland-based hand orthopaedic specialists and prospectively assessed to determine inter-rater reliability and diagnostic accuracy of individual TFCC diagnostic tests and a range of clinical parameters. The tests were compared against the criterion measure of specialist diagnosis based on MRI scans. This pilot study indicated that the accuracy of TFCC diagnostic tests were limited, with many tests failing to meet acceptable thresholds for diagnostic accuracy statistical metrics, and not being statistically significant. Overall, several tests indicated moderate usefulness for confirming TFCC injuries but limited usefulness for excluding such injuries. The ulnar fovea sign test had 0.50 sensitivity, 0.57 specificity. The piano key test had high specificity and positive predictive (PPV) values of 100%, but low sensitivity value of 0.13. The shear test had high specificity (0.86) and positive likelihood ratio (LR+) of 3.06. The grind test had sensitivity of 0.50, specificity at 0.86, LR+ of 3.50, negative likelihood ratio (LR-) of 0.58, PPV of 89%, negative predictive value (NPV) of 43%. The GRIT test specificity of 0.14, sensitivity of 0.56, LR+ 3.06, LR– 0.66 and NPV of 13%.

A concurrent reliability study of 20 participants showed high levels of inter-rater reliability for the grind, ulnar fovea sign and piano key TFCC diagnostic tests with 0.57, 0.57 and 0.51 kappa scores. The shear test had the lowest levels of inter-rater reliability at 0.01. GRIT had an intra-class correlation of 0.60, and standardised grip strength in neutral was 0.88.

The results of this pilot study have reinforced the inability of a singular diagnostic test to accurately determine TFCC injuries, but a combination of nine variables within the clinical examination has shown to increase the predictability of TFCC injuries. These were: being of male gender, strain mechanism of injury, the presence of constant symptoms, presence of crepitus, pain intensity with pronation-based ADLS, presence of pain with supination-based ADLS, passive radial deviation and pronation range of motion, and grip strength in a neutral position. This model was shown to accurately predict the presence of a TFCC injury, in this participant cohort.