Clinical exams more sensitive, but MRIs more specific for diagnosis of wrist injuries

With its 40-plus ligaments, triangular fibrocartilage and 8 bones, the painful wrist is a Rubik’s cube of potential diagnoses. This study compares the relative efficiency of clinical examination and wrist MRI in the accurate diagnosis of mechanical wrist pathology.

Imaging can be helpful and an essential part of the wrist pain workup. Plain X-rays, especially with a grip view, can reveal carpal collapse patterns and ulnar variance. Wrist arthrography generally has been abandoned in favor of MRI. But all wrist MRIs are not equivalent. Many are done without specific wrist coils or sequences and read by radiologists without an intimate knowledge of wrist anatomy. The use of gadolinium may further enhance the ability to define ligament injury. We looked at a series of referred wrist pain with accompanying MRI and found that only 8% of the time did it change the diagnosis or treatment plan: one was a case of Kienbock’s disease and the other an occult pisotriquetral ganglion. The best MRI still has poor resolution for lunatotriquetral, peripheral TFC, ulnar extrinsic and chondral lesions. Only 56% of patients in this British study had MRIs. In the remainder, the authors proceeded directly to arthroscopy. In the United States, for soft tissue mechanical wrist pain, plain X-rays and wrist MRIs are still part of the routine workup before wrist arthroscopy.

Wrist arthroscopy is the accepted gold standard used in this paper, but it may be tarnished. One study showed an interobserver agreement of only 84% when identical video clips were analyzed by multiple arthroscopists. Wrist arthroscopy is particularly useful for defining the extent of the tear and the joint's reaction to it, for the diagnoses to which MRI is blind, and for multiple lesions. In many instances, it offers a therapeutic solution.

The key take-home message of this article is that a complete physical examination of the wrist with provocative testing is still an essential part of making a clinically meaningful diagnosis and ultimately an appropriate treatment algorithm in soft tissue mechanical wrist pain.

“There is no significant difference in the diagnostic accuracy of clinical examination or MRI to diagnose wrist pathology,” is the key statement by these authors. In many ways, this is important information as there is an increasing use of MRI and other expensive imaging techniques to help evaluate problems of the wrist. A well-trained examiner can usually arrive at a correct diagnosis from a good history, routine X-rays and clinical exam. However, “well-trained” is key. A good example is wrist pain after trauma. If a fracture or instability has been ruled by X-ray and exam, well-trained orthopedists know this may take 6 months to 9 months to resolve.

However, this study has a serious flaw starting with the title. To the authors, “clinical exam” is meant to include physical exam and arthroscopy. Arthroscopy is not a “clinical exam.” It is an invasive procedure that is often not necessary and is also known to not correlate especially well with symptomatic clinical conditions. This study would be enhanced by eliminating some multiple, uncontrolled variables that the authors use to arrive at their conclusions.

The authors highlight the continued importance of a good clinical exam, although the rigors and consistency of teaching and reproducing a good clinical exam are not identified. MRIs in the United States are often used as justification or confirmation to proceed with surgery, which may then include arthroscopy. This study confirms what many of us believe, that both MRI and arthroscopy are unnecessary. However, MRI is likely here to stay as long as it is covered under insurance, which may not be the case in the United Kingdom, since it is often at the patient’s request and provides adjunctive information in a noninvasive means.