Mechanical evaluation of the scaphoid shift test

[Establishing a standardized diagnostic Procedure for sonographic Imaging and Evaluation of the scapholunate Ligament]

BACKGROUND

Ultrasound has not yet been established in the diagnostic workup of scapholunate ligament lesions. We aimed to develop a standardised examination procedure to visualise and evaluate the SL ligament.

PATIENTS AND METHODS

Forty patients (70 hands) were examined prospectively with ultrasonography and the results were compared with arthroscopy and MRI findings. We studied the visibility of the SL ligament and the SL distance on side-to-side comparison and performed a method comparison between MRI/arthroscopy and ultrasound, testing for distinction and accordance. Cut-off values for the SL distance indicating a lesion were determined and all parameters were used for developing a score.

RESULTS

An intact ligament appears as a hyperechogenic, fibrillary structure and shows discontinuity or a hypoechogenic space when injured. An intact ligament was visible dorsally in 89.6 % and palmarly in 83.3 %. The SL distance for an intact ligament was 5/2/5.1 mm for the dorsal/middle/palmar aspect (range 3.2-6.7/0.9-4/3.1-7.8 mm) and 6.4/3/6.3 mm (range 5-9.4/2-6.2/4-9.3 mm) for a lesion. The difference between the right and left hand with an intact ligament was a maximum of 2.1/1.1/1.8 mm, an average of 0.4/0.2/0.2 mm; in case of an injury, the maximum difference was 1.2/0.9/1.1 mm. Distance values for radial and ulnar deviation were physiological but partly unpredictable. The cut-off values determined for a lesion are 5.05 mm for the dorsal aspect (sensitivity/specificity 0.95/0.60), 1.95 mm for the middle (1/0.62) and 6.15 mm for the palmar aspect (0.55/0.85). The created sonographic SL ligament score has a high AUC (area under the curve) of 0.93, a sensitivity of 85 % and a specificity of 90 %.

CONCLUSION

The parameters, especially when combined to a score, allow to state whether the SL ligament is intact or not. Ultrasound can, therefore, be recommended as a diagnostic and screening method for an SL ligament lesion und should be used as a routine tool. The criteria must be checked from a perspective with high case numbers.

Feasibility of ultrasound-based measurement of dorsal scaphoid displacement: A 3D-model study

The present study aimed to develop a reliable dynamic measurement technique, which can be used directly in the outpatient setting, based on dorsal subluxation of the scaphoid on scaphoid shift test. This study was designed to evaluate feasibility and to quantify dorsal subluxation of the scaphoid in relation to the lunate. Based on a scaphoid shift test under ultrasonography, a standardized 3D test model was developed to measure subluxation. Sagittal subluxation ranged between 0 and 6 mm, as checked on the implemented scale. Four hand surgeons trained in ultrasonography (experience level II-V) performed blinded measurements (total of 52, n = 13 per investigator) with a standardized measurement protocol. Dorsal subluxation of the scaphoid was measured in relation to the lunate. Interobserver reliability on intraclass correlation coefficient (ICC) was excellent, at 0.97 (95% confidence interval, 0.930-0.992). Mean overall absolute measurement error was 0.27 mm ± 0.21. Dorsal subluxation of the scaphoid can thus be accurately measured on ultrasound with excellent interobserver reliability, quantifying and improving clinical assessment of scapholunate instability.

[Examination of the wrist and hand]

The wrist and hand form a highly complex organ that is of great importance in almost all daily activities. The hand serves as a tool and an organ of sense. Injuries of the hand and wrist as well as mechanical, neurological or systemic inflammatory changes are common. Taking a detailed history can already lead to a diagnosis. Almost all structures of the hand are easily accessible for clinical examination, i. e. inspection, palpation and clinical tests, including dynamic testing. Diagnostic imaging completes the examination procedure.

[Examination of the wrist and hand]

The wrist and hand form a highly complex organ that is of great importance in almost all daily activities. The hand serves as a tool and an organ of sense. Injuries of the hand and wrist as well as mechanical, neurological or systemic inflammatory changes are common. Taking a detailed history can already lead to a diagnosis. Almost all structures of the hand are easily accessible for clinical examination, i. e. inspection, palpation and clinical tests, including dynamic testing. Diagnostic imaging completes the examination procedure.

Open Treatment of Acute Scapholunate Instability

Acute treatment of scapholunate instability is important to prevent future complications of dorsal intercalated segment instability and scapholunate advanced collapse. An understanding of the fundamental normal and abnormal mechanics of this problem is vital. Diagnosis in the acute phase is based on clinical and radiographic findings and treatment focuses on primary scapholunate interosseous ligament repair with a reinforcing dorsal capsulodesis. Suture anchor repair with a modified "double-dorsal" capsulodesis is described. Current data show that open repair is a viable option in the acute setting with most patients demonstrating good to excellent functional, clinical, and radiographic results.

The value of provocative tests for the wrist and elbow: a literature review

To describe and determine the usefulness of provocative tests for the wrist and elbow a literature search was performed. A total of 31 diagnostic studies were identified, assessed, and ranked. The highest ranking tests had a mean positive likelihood ratio of ≥2.0, or a mean negative likelihood ratio of ≤0.5, from more than one study. The highly recommended tests were found to be the Phalen's, Tinel's test for carpal tunnel and cubital tunnel, and modified compression test, scaphoid shift test, and elbow flexion test. A total of 14 tests met our requirements to be considered a recommended test. A greater number of provocative tests either do not have adequate data to support their usefulness or their clinical utility has not been assessed. This information may assist hand therapists in choosing which provocative tests are considered clinically useful in improving the probability of the presence or absence of pathology in the hand, wrist, and elbow.

LEVEL OF EVIDENCE

NA.

[Scaphotriquetral capsulodesis for scapholunate instability]

OBJECTIVES

Scapholunate ligament injuries may lead to scapholunate instability and wrist osteoarthritis. Many surgical techniques have been described to repair these injuries. The goal of our study is to assess the clinical results after capsulodesis with the scaphotriquetral ligament for scapholunate instabilities.

METHODS

Twenty-eight patients, 22 men and six women, were operated for scapholunate instability between January 2006 and December 2008. The average age was 37.8 years, and the average time between trauma and surgery was 9.9 months. The scaphoid shift test was present in 26 patients. All patients underwent static and dynamic X-rays of the wrist and scan. A capsulodesis with scaphotriquetral ligament was performed in all patients.

RESULTS

At 24 months follow-up, a 13° significant decreased of wrist range-of-motion was noted. The strength was significantly improved after surgery. The wrist stability was improved in 26 patients. Concerning pain, a significant reduction was noted with Analogical Visual Scale after surgery (p<0.005). Twenty-one patients returned to their previous work. Complications were reflex dystrophy in one patient and wrist infection in one patient.

CONCLUSION

Many techniques were described for treatment of scapholunate injuries, from the simple scapholunate ligament suture to partial wrist arthrodesis. Capsulodesis with scaphotriquetral ligament improves grip strength, decreases wrist instability and pain with a slight lost of range-of-motion.

The diagnosis and treatment of scapholunate instability

Scapholunate instability is the most common form of carpal instability. Pain produced by this condition is caused by the wrist's inability to sustain physiologic loads because of an injury to the linkage between the scaphoid and lunate. The term scapholunate instability may describe a wide spectrum of clinical conditions ranging from mild wrist dysfunction and partial ligamentous tear to debilitating pain with associated rupture of the scapholunate interosseus ligament complex. This article reviews the pathophysiology of scapholunate instability and its identification and treatment.

Physical examination of the wrist

Physical examination of the wrist requires knowledge of wrist anatomy and pathology to make a diagnosis or narrow the differential diagnosis. Symptoms are provoked by palpation and signs are produced by manipulation. Negative findings elsewhere in the wrist are important. Final diagnosis may require diagnostic imaging. By having all three methods of assessment agree one is assured of correct diagnosis. The physical examination of the wrist is not unlike that of other joints, in that a systematic approach includes observation, range of motion, palpation, and special tests.

Physical examination of the wrist

Physical examination of the wrist requires knowledge of wrist anatomy and pathology to make a diagnosis or narrow the differential diagnosis. Symptoms are provoked by palpation and signs are produced by manipulation. Negative findings elsewhere in the wrist are important. Final diagnosis may require diagnostic imaging. By having all three methods of assessment agree one is assured of correct diagnosis. The physical examination of the wrist is not unlike that of other joints, in that a systematic approach includes observation, range of motion, palpation, and special tests.

The diagnosis and treatment of scapholunate instability

Scapholunate instability is the most common form of carpal instability. Pain produced by this condition is caused by the wrist's inability to sustain physiologic loads because of an injury to the linkage between the scaphoid and lunate. The term scapholunate instability may describe a wide spectrum of clinical conditions ranging from mild wrist dysfunction and partial ligamentous tear to debilitating pain with associated rupture of the scapholunate interosseus ligament complex. This article reviews the pathophysiology of scapholunate instability and its identification and treatment.

Stress views in the radiography of scapholunate instability

AIM

On the suspected carpal instabilities stress views are recommended but not often used. The present study evaluates the reliability of the dorsal and volar stress radiographs on patients with posttraumatic wrist pain.

PATIENTS AND METHODS

Stress radiographs of the wrists were examined in 22 patients with chronic wrist pain and the results were compared with scaphoid shift test and standard and positional views. The stress examination consists of applying to the wrist dorsal and volar stresses on the hand.

RESULTS

Static scapholunate instability was diagnosed in 4 patients in whom 3 of them had positive scaphoid shift test sign as well. There were, however, 18 patients with dynamic scapholunate instability in whom the standard films were normal but dorsal stress radiography showed gap greater than 3mm between the scaphoid and lunate.

CONCLUSION

Stress tests may provide considerable information in the evaluation of a patient who has a painful wrist in whom routine and special views do not demonstrate scapholunate dissociation.

Quantitative assessment of the midcarpal shift test

The subjective, clinical midcarpal shift test was compared with a quantitative measurement of carpal volar/dorsal translation versus ulnar deviation using a mechanical testing system. Testing was performed on 19 healthy volunteers (mean age, 33 years) and 3 patients (four wrists; mean age, 23 years) who had been diagnosed with ulnar midcarpal instability, a nondissociative form of carpal instability. During physical examination, each subject's wrist was graded I to V using the previously described classification of the degree of laxity and clunk observed with the midcarpal shift test. Each subject was also evaluated using a quantitative mechanical testing system that simulates the subjective clinical test. The testing system measures displacement of the distal carpal row, more specifically, the capitate, as the wrist is moved from neutral to ulnar deviation under a constant axial load of 44 N directed volarly at the head of the capitate. Reflective markers were attached to the skin above the proximal and distal ends of the third metacarpal and at the point where the 44-N load was applied to the carpus. Motion of the markers was used to calculate ulnar deviation and dorsal/volar translation of the carpus. The maximum slope of the carpal translation versus ulnar deviation curve was measured for each subject and compared with the results of the clinical midcarpal shift test. Higher maximum slopes were seen in subjects with the higher grades of carpal laxity. There were also differences with regard to the point at which the clunk occurred; the higher the clinical grade of laxity, the greater the ulnar deviation of the wrist at the point at which the clunk was observed. These differences were not significant, however. These data confirm the validity of the clinical test and establish its usefulness as a diagnostic indicator of midcarpal nondissociative carpal instability. The mechanized test also may be useful as a biomechanical marker, enabling the results of ligament sectioning to be effectively compared with defined clinical laxity.

The effects of exercise on ligamentous stiffness in the wrist

The purpose of this study was to determine if exercise alters wrist joint laxity, as measured by the mechanical behavior of the scaphoid bone. The load-displacement behavior of the scaphoid was studied in the palmar-dorsal direction in both wrists of 7 healthy volunteers (n = 14) before and after 2 exercise protocols (grip and push-up). When compared to the rested values, both exercise protocols significantly increased the displacement at 40 N by 47% (grip) and by 34% (push-up). Accordingly, the stiffness decreased significantly by 36% (grip) and by 32% (push-up). Partial recovery was documented after 1 hour of rest and there were no differences between any of the groups after 24 hours of rest. The increase in laxity documented during these exercise protocols reduces the ligament loads at comparable wrist positions and may thereby reduce the likelihood of traumatic ligamentous injury during participation in strenuous activity or sports.