Carpal Instability: I. Pathoanatomy

Gantry-free cone-beam CT arthrography for diagnosis of scapholunate ligament injuries: accelerating the preoperative work-up in acute wrist trauma

OBJECTIVE

Combining fluoroscopy and high-resolution cone-beam CT (CBCT) in a multipurpose scanner without a conventional gantry holds the potential for time-saving in musculoskeletal interventions. This study investigated the performance of gantry-free CBCT arthrography in patients with suspected scapholunate ligament (SLL) tears.

MATERIALS AND METHODS

Fifty-five patients (29 men, 46.0 ± 15.3 years) who underwent preoperative gantry-free CBCT arthrography between June 2021 and March 2024 were analyzed retrospectively. Three radiologists assessed CBCT arthrograms for tears of the palmar and dorsal SLL segments. Surgical reports served as the reference standard for calculating indicators of diagnostic accuracy. Interreader agreement was tested by computing Krippendorff α. Radiation dose and examination time were recorded.

RESULTS

Tears of the palmar and dorsal SLL segment were recorded in 25 (45%) and 6 patients (11%), respectively. CBCT arthrography facilitated good sensitivity (range for all readers: 84-92%) and excellent specificity (93-97%) in the assessment of the palmar SLL. For the dorsal SLL, sensitivity (83-100%) and specificity (96-98%) were even higher. Substantial agreement was determined for both the palmar (α = 0.83, 95% CI: 0.74-0.90) and dorsal SLL (0.84, 0.70-0.95). The mean volume CT dose index for CBCT arthrography was 3.2 ± 1.4 mGy. Not requiring patient repositioning, the median time between fluoroscopy-guided contrast injection and CBCT was 3:05 min (2:31-3:50 min).

CONCLUSION

Gantry-free CBCT arthrography allows for excellent accuracy in the preoperative diagnosis of SLL tears with low radiation dose. The ability to alternate between fluoroscopy and CBCT without repositioning facilitates a "one-stop-shop" approach with short examination time.

KEY POINTS

Question Performing fluoroscopy-guided arthrography and high-resolution cone-beam CT without patient repositioning appears advantageous for the preoperative work-up of distal radius fractures with concomitant scapholunate ligament injuries. Findings Gantry-free cone-beam CT arthrography allowed for short examination times and high diagnostic accuracy for either segment of the scapholunate ligament (89-98% versus surgery). Clinical relevance Preoperative assessment of scapholunate instability influences treatment since surgeons can reduce radius fractures and perform osteosynthesis via a dorsal portal to simultaneously stabilize the scapholunate compartment or use an additional dorsal access route for ligament suture and transfixation.

Surgical Techniques in Nontraumatic Midcarpal Instability: Evaluating the Dorsal Capsulodesis and 3-Ligament Tenodesis Technique

BACKGROUND

Surgical management of midcarpal instability (MCI), also referred to as carpal instability nondissociative, remains controversial because of limited evidence on different techniques. This study aimed to assess and compare differences in patient-reported pain, hand and wrist function, satisfaction, range of motion, and return to work in patients with nontraumatic MCI who underwent surgical treatment either through dorsal wrist capsulodesis or 3-ligament tenodesis (3LT).

METHODS

Patients with MCI and persisting complaints after conservative therapy treated with 3LT or dorsal capsulodesis were included. Patients with posttraumatic instability were excluded. Primary endpoints included the Patient Rated Wrist Evaluation and Satisfaction with Treatment Result Questionnaire at 12 months postoperatively. All data were analyzed retrospectively.

RESULTS

A total of 91 patients treated with dorsal capsulodesis and 21 treated with 3LT between December of 2011 and December of 2019 were included. At 12 months postoperatively, both treatment groups reported significant improvements in pain and function scores. However, at 3 months postoperatively, the dorsal capsulodesis group exhibited significantly better outcomes, followed by a greater return-to-work rate (72%) compared with the 3LT group (50%). However, the capsulodesis group demonstrated a decreased range of motion at 3 months that was restored at 12 months postoperatively. No significant difference in satisfaction with treatment was observed.

CONCLUSIONS

Both 3LT and dorsal capsulodesis demonstrate promising results for addressing nontraumatic MCI. However, considering the quicker recovery and faster return to work associated with dorsal capsulodesis, the authors recommend favoring capsulodesis over 3LT when both surgical options are deemed suitable for the patient.

[Carpal Malalignment in Malunited Fractures of the Distal Radius]

PURPOSE

To evaluate and classify carpal alignment in malunited fractures of the distal radius.

MATERIALS AND METHODS

On standardized lateral radiographs of the involved wrist of 72 patients with a symptomatic extra-articular malunion of the distal radius, 43 with a dorsal and 29 with a palmar angulation, radius tilt (RT), radiolunate (RL) and lunocapitate angle were measured. Malposition of the radius was defined as RT plus 11° in dorsal malunion and RT minus 11° in palmar malunion. A palmar tilt of the radius was marked with a minus sign. At the time of corrective osteotomy 9 dorsal malunions underwent for different reasons evaluation of the scapholunate ligament with 4 having a complete scapholunate ligament disruption.

RESULTS

With respect to the RL-angle, carpal malalignment was categorized as follows: type P with a RL-angle less than -12°, type K with a RL-angle between -12 and 10°, type A with a RL-angle more than 10°, but less than the malposition of the radius, type D with a RL-angle greater than the malposition of the radius. All types of carpal malalignment were found in both, dorsally and palmarly tilted malunion. Type A carpal alignment was identified as the leading type in dorsal malunion (25 out of 43 patients), whilst in palmar malunion colinear subluxation of the carpus (type C) was the dominant type (12 out of 29 patients). To return the hand to a neutral position the rotation of the lunate was compensated by a contrarotation of the capitate in the dorsal malunion. In the palmar malunion a dorsal extension of the capitate returned the hand to a neutral position. In 4 of the 5 patients with type D carpal alignment, who had scapholunate ligament evaluation, a complete ligament tear was found.

CONCLUSION

In this study four different types of carpal alignment in malunited extra-articular fractures of the distal radius were identified. Based on this data we suspect that type D carpal alignment in dorsal malunion may be associated with a scapholunate ligament tear. Therefore, we recommend wrist arthroscopy for this group of patients.

[Postoperative imaging of the musculoskeletal system - hand]

BACKGROUND

Postoperative imaging is essential to document the surgical outcome of the musculoskeletal system of the hand.

OBJECTIVES

Common radiological findings in the postoperative musculoskeletal system of the hand are explained in the context of the preoperative findings.

MATERIALS AND METHODS

For important surgical procedures of the hand, classifications, surgical procedures, and complications are presented. Diagnostic criteria in postoperative radiography and computed tomography (CT) imaging are described for each indication group.

RESULTS

Clinical information and postoperative findings are systematically presented for fractures of the radius, scaphoid, metacarpal and phalanges, scapholunate dissociation, perilunate injuries and for procedures of arthrodesis and arthroplasty in the hand. Complications are pointed out.

DISCUSSION

Precise reporting in postoperative radiography and CT imaging of the hand is based on a well-defined order, a standardised examination technique and on synoptic evaluation of clinical and radiological criteria.

Wrist Trauma: More Than Bones

Acute and subacute wrist trauma predominantly consist of fractures of the distal radius in elderly patients and most frequently carpal fractures (scaphoid, followed by triquetrum and hamatum) and avulsion fractures of the ulnar styloid in younger patients, especially in sports-related injuries but also in work activities. The initial radiographs may miss the fractures and result when untreated in complications as nonunion, osteonecrosis, and degenerative osteoarthritis.

Fractures of the distal radius and of the scaphoid may be associated with ligament injuries, most frequently the scapholunate complex, which are often overlooked at the emergency department. Patients without osseous injuries may present intrinsic and extrinsic ligament tears that may lead to carpal instability when they are clinically and/or radiologically missed.

Therefore, in acute and subacute setting, computed tomography may be helpful for the detection of subtle fractures, and magnetic resonance imaging, for the early diagnosis of occult fractures and ligament injuries.