Demonstration of the scapholunate space with radiography

Measurement of Scapholunate Joint Space Width on Real-Time MRI-A Feasibility Study

INTRODUCTION

The scapholunate interosseous ligament is pivotal for wrist stability, and its impairment can result in instability and joint degeneration. This study explores the application of real-time MRI for dynamic assessment of the scapholunate joint during wrist motion with the objective of determining its diagnostic value in efficacy in contrast to static imaging modalities.

MATERIALS AND METHODS

Ten healthy participants underwent real-time MRI scans during wrist ab/adduction and fist-clenching maneuvers. Measurements were obtained at proximal, medial, and distal landmarks on both dynamic and static images with statistical analyses conducted to evaluate the reliability of measurements at each landmark and the concordance between dynamic measurements and established static images. Additionally, inter- and intraobserver variabilities were evaluated.

RESULTS

Measurements of the medial landmarks demonstrated the closest agreement with static images and exhibited the least scatter. Distal landmark measurements showed a similar level of agreement but with increased scatter. Proximal landmark measurements displayed substantial deviation, which was accompanied by an even greater degree of scatter. Although no significant differences were observed between the ab/adduction and fist-clenching maneuvers, both inter- and intraobserver variabilities were significant across all measurements.

CONCLUSIONS

This study highlights the potential of real-time MRI in the dynamic assessment of the scapholunate joint particularly at the medial landmark. Despite promising results, challenges such as measurement variability need to be addressed. Standardization and integration with advanced image processing methods could significantly enhance the accuracy and reliability of real-time MRI, paving the way for its clinical implementation in dynamic wrist imaging studies.

The Sensitivity of the Scapholunate Interval and Bony Landmarks to Wrist Rotation on Posteroanterior Radiographs

BACKGROUND

The objective of this study was to examine the effect of wrist rotation on the scapholunate interval in the posteroanterior radiograph and to identify radiographic landmarks on the posteroanterior projection that can be used to assess position.

METHODS

Eleven healthy cadaveric wrists were radiographed in the neutral position and subsequently were rotated and imaged from 30° pronation to 30° supination in 10° intervals. At each interval, the scapholunate interval was measured as well as the following landmarks: (1) the visible perimeter of the base of the hook of the hamate; (2) the radial-ulnar distribution of the dorsal nonarticular surface of the distal third metacarpal head; (3) the radial-ulnar distribution of the pisiform about the longitudinal axis of the ulna; and (4) the overlap of the pisiform and triquetrum.

RESULTS

The scapholunate interval was largest in the neutral position and linearly decreased by 34% for every 10° of pronation and decreased nonlinearly by 86% after the first 10° of supination. The appearance of the distal third metacarpal head was shown to be sensitive to both pronation and supination. The perimeter of the hook of the hamate and the distribution of the pisiform compared to the ulna were both shown to be sensitive to supination, whereas overlap of the pisiform and triquetrum was not shown to be sensitive to either direction of rotation.

CONCLUSIONS

Our results highlight the significant effect of rotation on radiographic landmarks at the wrist, indicating that 10° of supination can drastically alter the developed radiograph.

Dynamic assessment of scapholunate ligament status by real-time magnetic resonance imaging: an exploratory clinical study

OBJECTIVE

Clinical-standard MRI is the imaging modality of choice for the wrist, yet limited to static evaluation, thereby potentially missing dynamic instability patterns. We aimed to investigate the clinical benefit of (dynamic) real-time MRI, complemented by automatic analysis, in patients with complete or partial scapholunate ligament (SLL) tears.

MATERIAL AND METHODS

Both wrists of ten patients with unilateral SLL tears (six partial, four complete tears) as diagnosed by clinical-standard MRI were imaged during continuous active radioulnar motion using a 1.5-T MRI scanner in combination with a custom-made motion device. Following automatic segmentation of the wrist, the scapholunate and lunotriquetral joint widths were analyzed across the entire range of motion (ROM). Mixed-effects model analysis of variance (ANOVA) followed by Tukey's posthoc test and two-way ANOVA were used for statistical analysis.

RESULTS

With the increasing extent of SLL tear, the scapholunate joint widths in injured wrists were significantly larger over the entire ROM compared to those of the contralateral healthy wrists (p<0.001). Differences between partial and complete tears were most pronounced at 5°-15° ulnar abduction (p<0.001). Motion patterns and trajectories were altered. Complete SLL deficiency resulted in complex alterations of the lunotriquetral joint widths.

CONCLUSION

Real-time MRI may improve the functional diagnosis of SLL insufficiency and aid therapeutic decision-making by revealing dynamic forms of dissociative instability within the proximal carpus. Static MRI best differentiates SLL-injured wrists at 5°-15° of ulnar abduction.

Scapholunate Ligament Rupture and Coincident Fracture Proximal Pole Scaphoid Presenting Late with Osteonecrosis: A Rare Case Report with Unique Management

CASE

A 29-year-old young active man with ununited necrosed proximal fifth of scaphoid with chronic scapholunate ligament disruption was managed by excision of proximal pole fragment and interosseous scapholunate reconstruction using modified Brunelli triple ligament tenodesis technique with satisfying outcome at 6 months and return to sports instructor job by the end of 1 year.

CONCLUSION

Meticulous understanding and algorithmic itemwise approach of injury components can lead to optimal management of complex unstable wrist injuries such as scapholunate dissociation. To the best of our knowledge, this is the first report on excision of proximal pole of scaphoid coupled with scapholunate ligament reconstruction.

Use of Generalizability Theory Evaluating Comparative Reliability of the Scapholunate Interval Measurement With X-ray, CT, and US

RATIONALE AND OBJECTIVES

There is no universally accepted standard technique for measuring the scapholunate interval and no specific sources of measurement error have been identified. We aimed to establish a set of normal radiological criteria for the scapholunate interval that could be used in comparative studies of wrist pathology to determine interobserver reliability and to identify potential errors that might influence measurements.

MATERIALS AND METHODS

A total of 60 healthy volunteers participated in the study. Scapholunate interval was measured by three independent observers using X-ray, CT, and US in four positions, including neutral, fist, radial and ulnar deviation. Inter-observer reliability was tested using intraclass correlation coefficient. Generalizability theory was applied to evaluate specific sources of measurement error related to participant, observer, imaging modality and measurement position.

RESULTS

In neutral position, the scapholunate interval measured by X-ray, CT, and US was 3.1 mm, 3.5 mm and 3.5 mm respectively. The interval remained constant during fist and radial deviation but decreased during ulnar deviation. Correlation coefficients ranged from 0.874 to 0.907 for X-ray, 0.773-0.881 for CT and 0.964-0.979 for US. In the generalizability study, the participant x modality x position interaction accounted for the largest proportion of total variance (29%).

CONCLUSION

X-ray, CT, and US are reliable modalities for measuring the scapholunate interval, with US having the highest reliability. Participant and position factors may independently contribute to measurement error. Therefore, standardized measurement positions are recommended to obtain reliable measurement results.

The tangential view described by Moneim to demonstrate scapholunate dissociation: an update

PURPOSE

Scapholunate dissociation is a common and significant injury to the wrist. Radiographs are important in the diagnosis of this injury and in the planning of treatment. The tangential radiograph view was described almost 40 years ago as a method for accurately measuring scapholunate gaps. The hand is positioned on a 20° foam rubber block and the thumb on the cassette, which positions the scaphoid and lunate articular surfaces parallel, without patient discomfort or effort. The goal of this study was to review this method with more recent data and in a larger group of patients.

METHODS

Radiographs of 31 patients who had scapholunate interosseous ligament tears and surgical repair over a 9 year period were retrospectively evaluated. Each of the four authors independently measured scapholunate gaps for posteroanterior and tangential views.

RESULTS

The tangential view gaps were significantly greater than the posteroanterior gaps overall. Similar results were found for borderline cases where the posteroanterior gap was less than 3 mm. Every tangential view gap measurement was greater than its respective posteroanterior gap with good inter-rater reliability.

CONCLUSION

The tangential view is a reliable radiographic method to identify scapholunate gaps. It should be obtained when there is clinical concern for scapholunate dissociation, especially in patients with borderline posteroanterior gaps.

Radiographic Scapholunate Interval in the Pediatric Population Decreases in Size as Age Increases

BACKGROUND

Widening of the scapholunate (SL) interval greater than 2 mm is diagnostic of an injury in adults; however, this absolute number cannot be used for skeletally immature individuals due to the ossification of the carpal bones. The purpose of this study was to determine age-appropriate normative values for the radiographic SL interval in the skeletally immature population.

METHODS

Normal pediatric wrist radiographs were identified. The radiographic SL interval was measured as the distance between the scaphoid and the lunate at the mid-joint space between the scaphoid and the lunate, and the SL and capitolunate angles were measured on lateral views. An initial inter-rater reliability assessment was completed with strong inter-rater reliability.

RESULTS

In all, 529 radiographic series of children (276 male), aged 4 to 17 years, were reviewed. A negative linear correlation between chronological age and distance at the mid-joint space was observed. The average values for the radiographic SL interval ranged from 9.07 to 1.57 mm. The average SL and capitolunate angles were 52.0° and 10.6°, respectively. No linear relationship was found between chronological age and SL or capitolunate angle (R = 0.07 and 0.03, respectively).

CONCLUSIONS

The visible radiographic distance between the scaphoid and the lunate decreases with increasing age as the carpal bones ossify. The normative values defined in this study can be used to determine whether a true widening of the SL interval is present in the pediatric population. No linear relationship exists between chronological age and SL or capitolunate angle.

Preoperative and Postoperative Imaging of Scapholunate Ligament Primary Repair and Modified Brunelli Reconstruction

Injury of the scapholunate ligament (SLL) complex can lead to scapholunate dissociation, characterized by scapholunate interval widening and volar rotary subluxation of the scaphoid. Loss of the mechanical linkage between the scaphoid and lunate results in carpal instability and eventual scapholunate advanced collapse (SLAC) arthropathy. SLL complex injuries vary from acute and traumatic to chronic and degenerative. A staging system can be used to guide treatment options for these injuries on the basis of the reparability of the SLL dorsal band, carpal alignment and malalignment reducibility, and cartilage damage. Preoperative imaging with radiography and MRI is a component of injury staging and aids in planning surgical procedures. If the SLL dorsal band is reparable, then direct primary ligament repair with dorsal capsulodesis or dorsal intercarpal (DIC) ligament transfer can be performed. If the SLL dorsal band is irreparable with normal alignment or reducible malalignment, then reconstruction can be performed. In the setting of irreducible malalignment or SLAC arthropathy, a salvage procedure can be performed. Knowledge of SLL primary repair and various reconstruction techniques is important not only when evaluating postoperative images but also for accurate description of SLL injuries and aiding the surgeon in treatment planning. The authors present the normal anatomy of the SLL complex, a staging classification of SLL injury with radiographic and MRI findings, and common surgical procedures. Special attention is given to the operative techniques and postoperative imaging appearances of primary SLL repair with DIC ligament transfer and modified Brunelli reconstruction. ^©RSNA, 2021.

Effectiveness of Percutaneous Pinning of Acute Partial Scapholunate Injury during Volar Locking Plating for Distal Radius Fractures: A Comparative Study of Pinning and Conservative Treatment

Backgroud

We hypothesized that concurrent temporary fixation of scapholunate ligament (SL) injury during volar locking plate (VLP) fixation of distal radius fractures (DRFs) would improve restoration outcomes based on both radiological and clinical results. Here, we performed a prospective, comparative study investigating the effectiveness of temporary percutaneous reduction/pinning during VLP fixation in DRFs.

Methods

The first 43 consecutive SL injuries were treated concurrently after VLP fixation by closed pinning (group 1); the next 36 consecutive injuries were treated nonoperatively (group 2). Patients were followed up for at least 5 years after treatment. Basic demographic data, radiological measurements, arthroscopic findings of SL injury, and other clinical outcomes were evaluated.

Results

The mean follow-up period was 7.2 years. No significant differences in basic demographic data were evident between groups. Fracture patterns were not distinctively different between groups. The initial scapholunate angle measured immediately after surgery was 23° ± 3° in group 1 and 38° ± 13° in group 2, indicating a significantly hyperextended scaphoid position in group 1. The final scapholunate angles were also significantly different between groups although the final angle in group 2 (58° ± 11°) was within normal limits. Final visual analog scale scores, Disabilities of the Arm, Shoulder and Hand scores, Gartland and Werley system scores, and wrist motions were not different between groups; however, grip strength at the time of final follow-up was closer to that of the contralateral uninjured wrist in group 1. Arthrosis was less advanced in group 1.

Conclusions

Temporary fixation for SL injury with a DRF can be an effective option for the maintenance of scapholunate angle. The non-fixed group exhibited a more pronounced collapse of the scapholunate angle although the angle was still within normal limits, and clinical outcomes were similar between groups regardless of the fixation status.

The Effects of Capitate Height Alteration on Dorsal Intercalated Segment Instability

Question/Purpose  Carpal kinematics may be influenced by the manipulation of carpal dimensions. This may provide a surgical alternative to unpredictable soft tissue reconstruction for scapholunate dissociation. The purpose of this study was to determine if altering capitate height can correct dorsal intercalated segment instability (DISI). Materials and Methods  Five cadaveric wrists had baseline radiolunate (RL) angles and scapholunate (SL) intervals measured fluoroscopically, confirming no baseline DISI. We simulated open- and clenched-fist testing via a constant load of the wrist extensors and sequential loading of the digital flexors. We confirmed no baseline static/dynamic DISI. The SL ligament and secondary stabilizers (scapho-trapezio-trapezoid [STT] and dorsal intercarpal ligaments) were transected. Repeat loading and fluoroscopic measurements confirmed creation of static DISI. Capitate height was altered in three interventions: 2 mm shortening osteotomy of capitate waist, 7 mm shortening osteotomy of capitate waist, and 2 mm lengthening of original capitate height by insertion of a spacer at capitate waist. The osteotomized capitate was stabilized with a Kirschner wire; RL angles and SL intervals were measured via fluoroscopy during open- and clenched-fist testing. Primary and secondary outcomes were change in RL angle and SL interval, from the DISI stage to each capitate shortening and lengthening stage. Results  SL ligament and secondary stabilizers sectioning created a DISI pattern, with abnormal RL angles (>15°) and widened SL intervals. Neither capitate shortening nor overexpansion corrected RL angles or SL intervals in any DISI-induced wrists. Conclusions  Under the conditions studied, isolated capitate shortening or lengthening did not correct radiographic DISI posturing of the lunate following sectioning of the SL and STT interosseous ligaments. Further study of carpal kinematics with more substantial bone changes and loading of adjacent joints may be beneficial. Clinical relevance  Surgeons performing capitate shortening osteotomy in isolation should not expect to improve DISI.

Dorsal Extrinsic Ligament Injury and Static Scapholunate Diastasis on Magnetic Resonance Imaging Scans

PURPOSE

Current biomechanical data suggest that static scapholunate (SL) ligament dissociation occurs only when there is loss of competence of the extrinsic ligaments either acutely or with attenuation over time. We aimed to identify whether patients with an SL gap greater than 2 mm demonstrated concomitant dorsal radiocarpal ligament (DRC) and dorsal intercarpal ligament (DIC) ligament changes on magnetic resonance imaging (MRI) scans that were identified as having an SL ligament tear.

METHODS

We included 90 patients who had a posttraumatic MRI scan of the wrist diagnosed with an SL injury. We recorded basic demographics; 2 attending fellowship-trained musculoskeletal radiologists evaluated the integrity of the SL, DRC, and DIC ligaments and graded these as normal, low-grade injury (sprain or partial tear) or full-thickness tear. The association between the integrity of the DRC and DIC ligaments and the presence of a scapholunate gap of 2 mm or greater was analyzed.

RESULTS

A total of 48 patients (53%) had an SL distance of 2 mm or greater on MRI. Of these patients, 28 (58%) had a partial or total tear of the DIC and/or DRC ligament. Compared with patients with an SL interval less than 2 mm, patients with an SL interval 2 mm or greater more often demonstrated DIC signal change (31% vs 12%), DRC signal change (52% vs 14%), or combined or isolated DIC and/or DRC signal change (52% vs 14%).

CONCLUSIONS

Dorsal extrinsic ligaments demonstrate MRI signal change suggestive of acute or chronic injury in patients with an SL interval 2 mm or greater more often than in patients with an SL interval less than 2 mm. These results reinforce that MRI findings of SL ligament tear need to be interpreted in a larger context, perhaps with additional attention to the DIC and DRC appearance upon MRI. In addition, MRI evaluation of dorsal extrinsic ligaments may aid in clinical decision-making for patients with SL injury.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic IV.

Radiographs Detect Dorsal Scaphoid Translation in Scapholunate Dissociation

Background  Dorsal translation of the proximal scaphoid pole onto the rim of the distal radius is a late finding associated with chronic scapholunate instability. Dorsal scaphoid translation (DST) has been identified by magnetic resonance imaging in patients with scapholunate dissociation (SLD). Purpose  The authors proposed to determine whether DST can be reliably detected on radiographs using two different measurement techniques. Patients and Methods  Lateral radiographs of 20 patients with operatively confirmed SLD were compared with 20 uninjured patients in blinded assessment. DST was assessed using the concentric circle and dorsal tangential line methods. Reliability was calculated using intraclass correlation (ICC) values. Results  Using both techniques, the scaphoid demonstrated increased dorsal translation in patients with SLD. Inter-rater reliabilities for the concentric circles and dorsal tangential line method on radiographs had ICCs > 0.80. Similarly, intra-rater reliabilities had ICCs > 0.90. Conclusions  Both the concentric circles and dorsal tangential line techniques had excellent reliabilities, but the dorsal tangential line method is clinically more practical. Type of Study/Level of Evidence  This is a Level III, diagnostic study.

Association of scapholunate dissociation and two-part articular fractures of the distal radius

Scapholunate dissociation may occur in association with distal radial fractures and is easily missed at initial presentation. The aim of this study was to examine variances in the scapholunate distance with respect to subtypes of two-part partial articular distal radial fractures. Axial computed tomography (CT) scans of acute two-part intra-articular radial fractures were assessed retrospectively from 80 patients and compared to 20 controls. From each scan, two images were analysed to identify the scaphoid, lunate and articular fracture line in the distal radius for fracture type categorization. The images were overlaid on a standardized distal radius template and the scapholunate distance measured. Significant increase in the scapholunate distance was noted in fracture subtypes: radial styloid oblique; dorsal ulnar column; sagittal ulnar column; and volar coronal. We conclude that these findings support the need for a higher index of suspicion for scapholunate dissociation in these distal radial fracture subtypes. Level of evidence: III.

The Optimal Location to Measure Scapholunate Diastasis on Screening Radiographs

BACKGROUND

Lack of a universally accepted location and normal value limits the utility of measuring scapholunate diastasis. The primary purpose of this study was to define the optimal location to measure the scapholunate gap throughout sequential ligament transections. Secondary purposes were to compare plain radiographs with fluoroscopy and to evaluate interrater reliability in measuring scapholunate diastasis.

METHODS

Five cadaver forearms were imaged with intact carpal ligaments and after sequentially transecting the scapholunate, radioscaphocapitate, and scaphotrapezium-trapezoid ligaments. Plain radiographs and static fluoroscopic images were obtained with wrists in neutral and 30° ulnar deviation for each stage. Multiple reviewers performed measurements of the scapholunate interval at 3 separate locations. Mean distances were calculated and pairwise comparisons between groups were made. Intraclass correlation was calculated to determine interrater reliability.

RESULTS

Overall, measurements made in the middle of the scapholunate joint had the smallest margins of error for all imaging modalities, ligament disruptions, and wrist positions. For normal wrists, the mean scapholunate measurements were all less than 2.0 mm at the middle of the joint, regardless of imaging modality or wrist position. Fluoroscopy detected significance between more stages of instability than plain radiographs at the middle of the joint.

CONCLUSIONS

Measurements in the middle of the scapholunate joint in neutral and 30° of ulnar deviation under fluoroscopic imaging best capture all stages of ligamentous disruptions. Measurements less than 2.0 mm at the middle of the scapholunate interval may be considered within normal range.

Radiographic Diagnosis of Scapholunate Diastasis in Distal Radius Fractures: Implications for Surgical Practice

Background  Radiographic diagnosis of scapholunate ligament injury (SLI) in the setting of distal radius fractures (DRFs) is challenging. It remains unclear to what extent radiographic diagnosis of SLI by a radiologist influences surgical decision-making regarding treatment of SLI. Purpose  We aimed to (1) identify the number of times that concerns for the possibility of concurrent SLI in the setting of a DRF had been raised by the radiologists, (2) identify how often the radiologist's diagnosis was confirmed by the treating surgeon, and (3) how many of the patients with a radiographic concern for SLI by the radiologist received operative treatment for the SLI. Patients and Methods  Based on Current Procedural Terminology codes, we identified 2,923 patients that were operatively treated for their DRF in 1 of 3 participating institutions in an urban city in the United States. We reviewed the medical charts of 654 patients who had a mention of scapholunate ligament (SL) distance in their radiography, surgery, or clinical notes. We then measured the SL distance and recorded patient, diagnosis, and treatment characteristics of all these patients. Results  A total of 200 out of 2,923 patients (6.8%) received a radiological diagnosis of SLI. In seven of these patients (3.5%), the surgeon confirmed the diagnosis of the radiologist. Four patients (2%) had operative repair of their SLI. Conclusion  Radiologists demonstrate a low threshold to identify SLI in the setting of DRFs, while the number of SLIs identified by the treating surgeon is a remarkably smaller number. Level of Evidence  Level II, prognostic study.

Traction Radiography for the Diagnosis of Scapholunate Ligament Tears

The diagnosis of scapholunate ligament injury by traction radiography was investigated within a consecutive study. The right wrists of 25 healthy volunteers and 22 wrists with arthroscopically proven complete scapholunate ligament tears were examined. Traction radiography was performed under fluoroscopy with a force of 5 kg applied to the thumb. In the normal wrists, this led to selective widening of the scapholunate joint space whereas the lunotriquetral distance remained unchanged. In 25 healthy right wrists, the median scapholunate distance measured 2.1 (range 1.3–2.6) mm on resting radiographs and 2.2 (range 1.7–3.5) mm on the stress radiographs. For the 22 wrists with complete scapholunate ligament tears, the median scapholunate distance was increased from 2.0 (range 1.0–3.0) mm to 3.8 (range 3.0–5.5) mm by traction (median difference of 1.8 (range 1.0–3.0) mm). In conclusion, a scapholunate distance of 3.0 mm or more in unloaded wrists or widening of the scapholunate interval by 1.0 mm or more under thumb traction should both be considered as pathological findings. We recommend traction radiography as a simple and valuable diagnostic procedure for suspected scapholunate ligament injury.

Radiographic evaluation of a novel horizontal dorsal intercarpal capsulodesis as a treatment of pre-arthritic scapholunate dissociation: a cadaver study

Dorsal capsulodesis is an important part of the treatment of pre-arthritic scapholunate instability. We designed an experimental study using 14 fresh-frozen cadaver wrists to demonstrate the efficacy of a new horizontal dorsal intercarpal capsulodesis. We sectioned the scapholunate ligament to create a scapholunate dislocation. Several radiographic views, static and 'in stress', were recorded and we statistically compared the scapholunate interval before and after the section of the scapholunate ligament, and after the creation of the capsulodesis. The results showed a significant decrease of the scapholunate interval after the creation of the capsulodesis, especially in neutral and maximal ulnar deviation of the wrist. They also proved that our cadaveric model is reliable. This study demonstrated that this novel capsulodesis reduces the scapholunate interval in a cadaveric model.

Comparisons of three radiographic views in assessing for scapholunate instability

BACKGROUND

Multiple wrist x-ray images have been described to assess for scapholunate (SL) instability. Some views may be redundant. The purpose of this study was to compare three plain x-ray views in identifying a traumatic diastasis of the SL interval.

METHODS

Nineteen patients (19 wrists) with a positive scaphoid shift test and surgically confirmed SL ligament damage were identified. There were 15 males and 4 females with a mean age of 39 years. Pre-operative x-rays were reviewed, including posteroanterior (PA) neutral and PA ulnar deviation views of the injured wrist, and PA clenched fist views of the injured and uninjured wrists. Dynamic SL instability was defined by an SL mid-interval gap of <3 mm and static SL instability by a gap of ≥3 mm in the PA neutral views. The mid-interval measurements were compared between x-ray images.

RESULTS

There were 10 dynamic and 9 static SL instability cases. The PA ulnar deviation and the PA clenched fist views showed significantly greater SL gaps in comparison to the PA neutral views in dynamic but not static SL instability cases. In both categories of instability, there was no significant difference in the SL gaps between the two stress images. The PA clenched fist view of the uninjured wrist revealed SL gapping of >3 mm in 50% of patients but with generally greater gapping in the clenched fist view of the injured wrist.

CONCLUSIONS

The PA ulnar deviation and clenched fist stress views were equally effective in showing a dynamic SL diastasis following wrist injury. Neither view was more effective than a neutral PA view in diagnosing static SL instability.

The modified Brunelli procedure for scapholunate instability: a single centre study

Management of scapholunate (SL) instability remains controversial. The modified Brunelli procedure is a soft tissue procedure that recreates the stabilising forces of the SL ligament using a split flexor carpi radialis tendon graft passed from volar to dorsal via a tunnel in the distal pole of the scaphoid. Thirteen consecutive patients with an average age of 35 years underwent the modified Brunelli procedure. Pain improved from a mean visual analog score of eight preoperatively to 1.5. The DASH score improved from a preoperative score of 55.4 to 34.9 as did the grip strength from 40% to 75% respectively. All wrist ranges of motion were decreased post-operatively in particular wrist flexion. SL ligament reconstruction using the modified Brunelli procedure resulted in satisfactory outcomes. Post-operatively patients were relatively pain free, with improved grip strength. The range of motion was reduced postoperatively, however did not restrict return to work or premorbid activities.

Use of external fixation for perilunate dislocations and fracture dislocations

The purpose of this study was to review clinical and radiographic outcomes of perilunate dislocations and fracture dislocations treated with external fixation and K-wire fixation. Twenty patients (18 males and two females) with a mean age of 38 years (range 18–59) who had an acute dorsal perilunate dislocation or fracture dislocation were treated with the use of wrist external fixator and K-wires. The injuries included 12 perilunate dislocations, seven trans-scaphoid perilunate fracture dislocations, and one trans-styloid perilunate fracture dislocation. The median time from trauma to operation was 8 h (2–12 h). Indirect reduction via ligamentotaxis was achieved in all perilunate dislocation, and provisional K-wire fixation was added. In five of seven trans-scaphoid perilunate fracture dislocations, indirect reduction was achieved; whereas in the other two as well as in the case of trans-styloid perilunate fracture dislocation, open reduction was required. External fixator was supplemented with K-wires for stabilization of the fractures and the intercarpal intervals. The interosseous and capsular ligaments were not repaired, even after open reduction of fracture dislocations. The mean follow-up was 39 months (range 18–68 months). Range of motion and grip strength were measured. Cooney’s scoring system was used for the assessment of clinical function. Radiographic evaluation included time to scaphoid union, measurement of radiographic parameters (scapholunate gap, scapholunate angle, lunotriquetral gap, and carpal height ratio) and any development of arthritis. The flexion-extension motion arc and grip strength of the injured wrist averaged 80 and 88%, respectively, of the corresponding values for the contralateral wrists. According to Cooney’s clinical scoring system, overall functional outcomes were rated as excellent in four patients, good in eight, fair in six, and poor in two. Eighteen patients returned to their former occupations. Two patients with a trans-scaphoid perilunate injury developed nonunion of the scaphoid; one of them required scaphoid excision and midcarpal fusion. Two patients had radiographic evidence of arthritis. The use of external fixation and provisional K-wire fixation for the treatment of acute perilunate dislocations is associated with satisfactory midterm functional and radiographic outcomes. This minimally invasive treatment option is simple, reliable, and minimally invasive method that provides proper restoration and stable fixation of carpal alignment.

Differentiating common causes of radial wrist pain

Radial wrist pain is a common patient complaint with a broad differential. Because treatment and prognosis differ, determining the underlying cause is key. This article reviews a case of intersection syndrome and compares it to other causes of radial wrist pain.

Scaphoid overstuffing: the effects of the dimensions of scaphoid reconstruction on scapholunate alignment

PURPOSE

Osteochondral replacement of the proximal scaphoid has been reported using a vascularized flap from the medial femoral trochlea. A concern with this technique is the loss of stability of the scapholunate relationship with resection of the scaphoid proximal pole. Overexpansion of the scaphoid dimensions (overstuffing) during scaphoid reconstruction with the osteochondral flap may play a role in maintaining scapholunate alignment. Our purpose was to determine if overstuffing the scaphoid can correct rotatory carpal instability in a cadaveric model studied radiographically.

METHODS

The radiolunate angle and scapholunate interval were measured for 5 fresh cadaver wrists. We completely incised the scapholunate interosseous ligament and performed an osteotomy to excise the proximal third of the scaphoid to simulate a proximal pole deficiency nonunion and create a dorsal intercalated segmental instability deformity. Radiographic measurements were repeated. The proximal pole of the scaphoid was replaced with its original piece of bone; radiographic measurements were repeated without scapholunate ligament repair. The osteotomy site was overstuffed with a 4-mm sawbone spacer without scapholunate ligament repair, and radiographs were obtained.

RESULTS

Sectioning of scapholunate ligaments and proximal pole excision successfully created carpal instability demonstrated by abnormal radiolunate angles. Without ligament repair, proximal pole replacement did not restore normal radiolunate angles. Expansion of the scaphoid dimensions corrected radiolunate angles on lateral unloaded radiographs and improved scapholunate intervals on clenched fist radiographs. These findings were statistically significant compared with the unexpanded (replaced) scaphoid.

CONCLUSIONS

These findings suggest that scaphoid reconstruction that results in expansion of the scaphoid's normal dimensions will restore carpal alignment without scapholunate ligament reconstruction.

CLINICAL RELEVANCE

Osteochondral reconstruction of difficult proximal pole nonunions may not require any preservation or reconstruction of scapholunate integrity if the reconstruction expands the normal dimensions of the native scaphoid. Scapholunate interval and carpal alignment may be restored by scaphoid over stuffing. The effects on increased contact pressure and range of motion require further investigation.

Radiographic evaluation of chronic static scapholunate dissociation post soft tissue reconstruction

The purpose of this study was to examine the radiographic outcomes of dorsal intercarpal ligament capsulodesis (DILC), documenting the time to carpal collapse postoperatively. From January 2008 to January 2011, 12 patients were identified with chronic scapholunate (SL) dissociation. The average follow-up period was 15.8 months. Paired t-tests were used preoperatively, one month after pin removal, and at final follow-up to determine significance in radiographic outcomes. The Disabilities of the Arm, Shoulder, and Hand (DASH) survey was administered to patients before and after surgery to assess subjective levels of pain, function, and satisfaction. Intraoperatively all deformities were reduced completely. One month after pin removal, the mean SL gap was 3.3 mm, the SL angle was 74°, the radiolunate (RL) angle was 17°, and the lunatocapitate (LC) angle was 8°. Only the SL angle improved; the other measurements remained unchanged. At final follow-up, the mean SL gap was 3.6 mm, the SL angle was 78°, the RL angle was 20°, and the LC angle was 10°. SL angle worsened, but with no statistically significant difference. The other radiographic measurements remained unchanged at final follow up. Wrist flexion and extension decreased from 76% and 69% of the contralateral side to 62% and 56% of the contralateral side after surgery. Grip strength was 64% of the contralateral side before surgery and 83% after surgery. Visual Analog Scale (VAS) results improved from 6.3 to 1.7, and DASH scores improved from 39 to 8 after the surgery. DILC cannot withstand large and repetitive forces. Carpal collapse recurred within a short time after DILC. However, our small patient numbers and short term follow-up preclude any conclusions with respect to clinical efficacy of this procedure. Limitations of this study include the fact that this is a retrospective study with no control group. In addition, it represents a single-surgeon series, which introduces a source of bias and carries the risk of technical and methodological flaws, which may have contributed to the observed radiographic outcomes.

Traction radiography for the diagnosis of scapholunate ligament tears: an experimental cadaver study

The aim of this experimental cadaver study was to verify that thumb traction radiography can be used to diagnose scapholunate interosseous ligament (SLIL) injury. Eight cadaver forearms were positioned vertically so that the thumb could be held in a Chinese finger trap and traction force applied using a 5 kg weight. Fluoroscopy was performed with the thumb unloaded and under traction, and then unloaded and under traction after division of the SLIL. The scapholunate joint gaps were measured electronically. The difference between the unloaded and loaded wrists with sectioned SLIL was not statistically significant. These results suggest that thumb traction radiography might not reliably detect acute, complete SLIL tears.

Management of soft-tissue injuries in distal radius fractures

Distal radius fractures account for approximately 15% of all fractures in adults, and are the most common fractures seen in the emergency department. Soft-tissue injuries associated with distal radius fractures may influence strategies for the acute management of the fracture, but also may be a source of persisting pain and/or disability despite fracture healing. This article describes soft-tissue injuries and considerations for treatment associated with distal radius fractures, including injuries to the skin, tendon and muscle, ligaments, the triangular fibrocartilage complex, neurovascular structures, and related conditions such as compartment syndrome and complex regional pain syndrome.

Comparison of radiographic stress views for scapholunate dynamic instability in a cadaver model

PURPOSE

Many different stress views for the diagnosis of scapholunate (SL) instability have been described in the literature. The purpose of this study is to compare these stress views and determine which view has the greatest utility for demonstrating SL gap radiographically.

METHODS

We performed a literature search for articles describing SL radiographic stress views. We created SL instability in 9 cadaveric wrists by ligamentous sectioning and imaged each specimen using all radiographic views found in the literature. These included the "clenched pencil" view, clenched fist views in varying positions, and traction views. Scapholunate gaps were measured using digital calipers.

RESULTS

We found 8 different SL radiographic stress views specifically described in the literature. In order to further characterize the best stress views, we studied additional parameters, including varied ulnar deviation and degree of obliquity. The clenched pencil view resulted in the most consistent views with the widest SL gaps. With clenched fist views, SL gap trended to a peak at 30° of ulnar deviation.

CONCLUSIONS

The clenched pencil view was the best stress view to demonstrate dynamic SL instability. It also allows for a contralateral comparison on 1 radiograph. We recommend this view when evaluating for SL pathology.

CLINICAL RELEVANCE

This assessment of relative diagnostic utility might assist clinicians in the creation and use of protocols for the diagnosis of dynamic SL instability.

Radiographic imaging of the wrist

Imaging techniques play an important role in evaluating the complex anatomy of bone and soft tissues of the wrist. The standard wrist radiographs and specialized views still form a very important imaging modality to unravel the wrist pathology in their simplest forms. This article discusses the routine radiography of the wrist followed by ancillary views and dynamic studies for each of the routine view described that helps reveal both static and dynamic pathologies. The literature search was carried out using the search strings or key words, and the databases were searched using the time frame of 1990 to 2011 that included Scopus, MD consult, Web of Knowledge, Pub Med, Ovid Medline and Cochrane Library. The print journals and books available at Manipal University library were hand searched and secondary search was done for the relevant articles included in the references of primary articles. Full articles as well as abstracts were used for the review.

Radiographic evaluation of the modified Brunelli technique versus the Blatt capsulodesis for scapholunate dissociation in a cadaver model

PURPOSE

A variety of soft tissue surgical procedures have been developed for treatment of scapholunate (SL) dissociation. The purpose of this study was to compare the degree of correction obtained (as measured on preoperative and postoperative radiographs) when performing the modified Brunelli technique (MBT) with that of the more commonly performed Blatt capsulodesis (BC) and to evaluate each technique after simulated wrist motion.

METHODS

Five cadaver wrists were used for this study. The SL interval, SL angle, and radiolunate angle were recorded radiographically, with the SL ligament intact, for each wrist in several loaded positions: neutral, flexion, extension, radial deviation, ulnar deviation, and clenched fist. The SL interosseous ligament was then completely incised, and the radiographic measurements were repeated to demonstrate SL instability. The radiographic measurements were then repeated after MBT reconstruction and after BC reconstruction. Additional radiographic measurements were taken after simulated wrist motion.

RESULTS

Sectioning of the SL ligament resulted in radiographic evidence of SL dissociation. Use of the MBT demonstrated improved correction of the SL interval and the SL angle in the clenched fist position, which was statistically significant when compared with BC. The correction for the SL angle was maintained on the MBT specimens with simulated wrist motion.

CONCLUSIONS

The results demonstrate that in this cadaver model, the MBT better restores the normal carpal relationship of the SL interval and SL angle when compared to the BC, as measured on radiographs. This correction might correlate with improved carpal dynamics and improved clinical outcomes.

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.

Perilunate dislocations and transscaphoid perilunate fracture-dislocations: a retrospective study with minimum ten-year follow-up

PURPOSE

Perilunate dislocations and transscaphoid perilunate fracture dislocations are associated with a high incidence of posttraumatic arthritis. According to the current literature, at medium-term follow-up, radiological signs of arthritis do not correlate with functional scores. The aim of this study was to evaluate patient hand function and the development of posttraumatic arthritis after perilunate dislocations (11 cases) and transscaphoid perilunate fracture dislocations (7 cases) at a minimum 10 years of follow-up.

METHODS

A retrospective review was performed including 18 patients with a minimum 10-year (average, 13 y) follow-up. The clinical results were evaluated using the Mayo wrist score and the patient-rated wrist evaluation. Radiological abnormalities were stratified using the Herzberg classification.

RESULTS

According to the Mayo wrist score, the authors found 5 excellent, 3 good, 7 fair, and 3 poor results. The mean Mayo wrist score was 76 (range, 60-90). There were 6 type A, 5 type A1, 6 type B1, and 1 type C, according to the Herzberg classification. Posttraumatic degenerative changes were observed in 12 cases.

CONCLUSIONS

The presence of radiological arthritis and static carpal instability did not cause reduced function at our minimum follow-up of 10 years. Based on our findings and previously reported series, we conclude that signs of posttraumatic arthritis after perilunate dislocations and transscaphoid perilunate fracture dislocations increase progressively but are well tolerated at an average follow-up of 13 years.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Results of the modified Brunelli tenodesis for treatment of scapholunate instability: a retrospective study of 19 patients

PURPOSE

Management of chronic scapholunate (SL) instability without osteoarthritis remains controversial. In order to recreate an SL interosseous linkage, some surgeons opt for a limited wrist arthrodesis, whereas others use soft tissue stabilization. The purpose of the current study was to review and assess the therapeutic benefit of the modified Brunelli tenodesis that used the flexor carpi radialis tendon to replicate the stabilizing ligaments of the scaphoid.

METHODS

Between 2001 and 2005, 19 tenodesis procedures have been performed to correct dynamic or static SL instability without osteoarthritis. On average, patients had surgery 15 months after injury. The mean follow-up was 37 months.

RESULTS

After surgery, 15 patients had no to mild pain with a mean visual analog scale score of 3 of 10. The average wrist motion was 50 degrees extension, 41 degrees flexion, 24 degrees radial deviation, and 29 degrees ulnar deviation (75%, 73%, 68%, and 86% of the uninvolved wrists, respectively). The grip strength was 78% of the uninvolved wrists. On radiographs, the mean static SL distance was 2.4 mm (2.8 mm before surgery). There was no widening of the SL gap compared to the immediate postoperative gap. The SL angle improved from a mean preoperative value of 61 degrees to 53 degrees immediately after surgery and rose again to 62 degrees at the time of the review. One patient developed a scapholunate advanced collapse wrist stage 2.

CONCLUSIONS

Ligament reconstruction using tendon grafts gave satisfactory results to correct reducible chronic SL instability without osteoarthritis. This repair technique achieved a relatively pain-free wrist, with acceptable grip strength and normal SL distance but with a loss in the arc of motion and a loss of correction of SL angle.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Fluoroscopic diagnosis of scapholunate interosseous ligament injuries in distal radius fractures

Early diagnosis of scapholunate interosseous ligament tears with distal radius fractures is likely important in treatment and outcome, but identification of these injuries has not been well explored. We asked whether there was a difference in the scapholunate interval between high-grade and low-grade tears of the scapholunate interosseous ligament in distal radius fractures, the best position of the wrists to identify any differences; we also asked what gap width accurately identified high-grade tears on fluoroscopic evaluation. We fluoroscopically evaluated the scapholunate gap in six different wrist positions and then performed arthroscopic examination in 45 distal radius fractures in 44 consecutive patients. The tears were classified as high-grade (Grade 3 or greater) or low-grade (Grade 2 or less) based on arthroscopic findings. We then compared the scapholunate gap measured on fluoroscopic images between the high-grade tear group and the low-grade tear group and between the different positions of the same wrist. The scapholunate gap was wider in the high-grade tear group than in the low-grade tear group and wider in ulnar deviation than in radial deviation. A 2-mm scapholunate gap appeared the best cutoff point for the fluoroscopic diagnosis. We concluded fluoroscopic examination is a good test for identifying high-grade tears of the scapholunate interosseous ligament in distal radius fractures.

LEVEL OF EVIDENCE

Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Diagnostic accuracy of plain radiographs and cineradiography in diagnosing traumatic scapholunate dissociation

OBJECTIVE

Missed tears of the scapholunate ligament (SLL) and scapholunate dissociation (SLD) after wrist injuries pose a high risk of post-traumatic osteoarthritis of the carpus. Plain X-rays and dynamic radiographic studies are frequently used for initial diagnostic work-up. Given the limited evidence of their accuracy, we retrospectively compared the radiographic findings of patients with suspected traumatic SLD with wrist arthroscopy as the accepted reference standard.

DESIGN AND METHODS

During a 6-year period, plain radiographs and DSA cineradiography scans were obtained from 198 patients who had sustained a hyperextension injury to their hand. Of those, 102 (72 men, 30 women, mean age of 42+/-12 years) subsequently underwent diagnostic arthroscopy. Digital images were reevaluated by experienced radiologists unaware of the arthroscopic findings for the presence or absence of SLD. We calculated the sensitivity (SN) and specificity (SP) with 95% confidence intervals (CI), and computed areas under the receiver operating characteristic curves (AUC/ROC).

RESULTS

Arthroscopy revealed 42 SLL ruptures, 13, 10, and 19 of which were classified as grade I (partial), II (complete with dynamic instability), or III (complete with static instability) respectively. Plain radiographs correctly identified 24 injuries (SN 57.1%, 95% CI 41.0-72.3%), and produced 1 false-positive result (SP 98.3%, 95% CI 91.1-100.0%). The scapholunate distance and the SL angle contributed independently to the diagnostic variance, with an AUC/ROC of 85.7% (95% CI 76.8-92.2%). Cineradiography had a sensitivity of 36 out of 42 (85.7%, 95% CI 71.5-94.6%), and a specificity of 57 out of 60 (95.0%, 95% CI 86.1-99.0%).

CONCLUSION

Pathological results on plain radiographs and cineradiography reliably indicate the presence of SLD after wrist trauma. Although non-conclusive, a negative dynamic study markedly reduces the pre-test probability of disease. Both methods remain key elements of primary diagnostic strategies for suspected traumatic SLD, and may facilitate the selection of additional 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.

Dorsal intercarpal ligament capsulodesis for chronic, static scapholunate dissociation: clinical results

The purpose of this study was to review and report the results of using a new procedure, the dorsal intercarpal ligament capsulodesis (DILC), to treat a group of patients with chronic flexible scapholunate dissociation. This was a prospective study of 21 patients (22 wrists), ranging in age from 16 to 62 years followed up for 1 to 4 years. For this study all patients returned to complete a questionnaire and have a physical examination performed by physicians and therapists independent of the treating surgeons and to obtain standardized radiographs of the wrists. Patient demographics, mechanism of injury, range of motion, and grip strength were recorded. Patients completed the Mayo wrist, Short-Form (SF)-12, and Disabilities of Arm, Shoulder and Hand (DASH) questionnaires. Results showed there were significant improvements in scapholunate angle and scapholunate gap at final follow-up examination, with minor loss of range of motion and grip strength. Patients were satisfied with the outcomes, showing an average score of 17 on the DASH and 83 on the SF-12. The DILC procedure is a reasonable option for treating chronic scapholunate dissociation. The procedure has conceptual advantages to recommend it: it avoids a tether between radius and scaphoid and keeps the proximal carpal row linked as a functional unit. It reduces the scapholunate angle and gap. Overall the results to date are quite encouraging.

Static scapholunate dissociation: a new reconstruction technique using a volar and dorsal approach in a cadaver model

We used 4 fresh-frozen cadaver arms to assess a method of reconstruction we designed for static scapholunate dissociation. The dorsal scapholunate ligament, scapholunate interosseous ligament, radioscapholunate, and radioscaphocapitate ligaments were sectioned. Radiographs were taken before sectioning, after sectioning, and after reconstruction. Passive motion was also measured before sectioning and after the repair. The dorsal scapholunate ligament was repaired directly; the palmar radioscapholunate and radioscaphocapitate ligaments were reconstructed using a free flexor carpi radialis tendon autograft and Mitek mini suture anchors (1.8-mm diameter and 5.4-mm length; Mitek Products, Norwood, MA) for anatomic fixation. An independent board-certified hand surgeon analyzed the radiographs of the wrists taken before and after sectioning and after reconstruction. Assessment of the unsectioned wrists revealed an average scapholunate angle of 45 degrees. After scapholunate dissociation was created the average scapholunate angle was 71 degrees. Repair of the dorsal scapholunate ligament alone did not improve the scapholunate angle. Average scapholunate angle after repair of the dorsal scapholunate ligament and reconstruction of the palmar ligaments was 43 degrees. Average range of motion on flexion, extension, and radial and ulnar deviation before ligament sectioning and after reconstruction was unchanged at 54 degrees, 59 degrees, 19 degrees, and 40 degrees respectively. This technique shows an improvement in scapholunate angle on lateral radiographs, and passive motion remained relatively unchanged.

Radiologic measurement of the scapholunate joint: implications of biologic variation in scapholunate joint morphology

To determine the optimal location for measurement of the scapholunate (SL) joint intercortical width, normal biologic variation in SL joint morphology was evaluated in 40 normal, skeletally mature wrists (16 volunteers, 24 cadavers) using thin-section 1.5T magnetic resonance imaging performed in the axial and coronal planes. The integrity of the SL ligaments was confirmed by magnetic resonance imaging and verified with anatomic dissection of the cadaver wrists. Patterns of SL articular morphology were qualitatively determined using similarity grouping. Scapholunate interval measurements were made at 3 locations each on the mid-SL joint image from both the axial and coronal planes: the articular margins (dorsal-palmar and proximal-distal) and midjoint. Three patterns of midjoint space cortical conformation were observed: parallel congruent (78%), inverted Y (15%), and point-like (8%). The most consistent and narrowest distance between the scaphoid and lunate was found at midjoint: coronal 1.45 mm (44% coefficient of variation) and axial 1.00 mm (22% coefficient of variation). This study demonstrated that measurement of the apparent SL joint interval in an inappropriate site, as with extended or flexed clenched fist views, may provide inaccurate SL joint interval distance assessments. Regardless of SL joint configuration, the midportion of the SL joint shows only moderate biologic variation and the least absolute measurement variance in width and should be the most precise part of the joint to measure. On magnetic resonance imaging, the normal SL joint interval measures less than 2 mm.

Postero-anterior radiography of the wrist: scapholunate ratios and joint projection shape analysis

A normal database of qualitative and quantitative data, obtained from standard posteroanterior wrist radiographs has been established which might be useful in clinical practice. Variations in the parameters obtained could provide an explanation for the variable carpal kinematics and multiple concepts of carpal instability described in the literature. Selected landmarks were digitized on 80 posteroanterior wrist radiographs of asymptomatic volunteers. Besides classical parameters, measurement of carpal dimensions and angular relationships were also taken. Two new parameters, the scapholunate ratios, are described which evaluate the relative lengths of the frontal projections of the scaphoid and lunate: these ratios might prove useful in the diagnosis of carpal instability. The shapes of the frontal projections of the radiocarpal, midcarpal and STT joint spaces were also analysed. Average values for parameters already reported in the literature agreed with previous findings. Some parameters, however, displayed important individual variations, the standard deviations ranging from 1 to 3 mm for dimensions and from 3 to 13 degrees for angular measurements. The posteroanterior and anteroposterior scapholunate ratios averaged 1.41 +/- 0.21 and 0.66 +/- 0.13 respectively. The potential clinical benefit of these ratios is discussed. Different types of joint space projection shapes could be determined. With respect to the difficulty of obtaining reliable lateral wrist radiographs, compared to posteroanterior radiographs, it is suggested that the clinical significance of the proposed parameters must be evaluated.

Dorsal intercarpal ligament capsulodesis for scapholunate dissociation: biomechanical analysis in a cadaver model

The purpose of this study was to evaluate in cadavers a new method for treating scapholunate dissociations, dorsal intercarpal ligament capsulodesis (DILC), and to compare its performance with that of a previously described soft tissue reconstruction, Blatt capsulodesis (BC). A cadaver model was used to simulate normal and abnormal wrist motions. The positions of the scaphoid and lunate and their changes with wrist motion and ligament condition were recorded using biplanar radiographs taken posteroanteriorly and laterally. The scapholunate gap was measured on the posteroanterior radiographs and the scapholunate angle was measured on the lateral view radiographs. Following scapholunate interosseous ligament sectioning, a diastasis developed between the scaphoid and lunate that was maximum in the clenched fist position 2.1 +/- 0.33 mm (mean +/- SEM) with the ligament intact versus 8.0 +/- 1.74 mm after the ligament was sectioned. Dorsal intercarpal ligament capsulodesis reduced gap formation more than BC, including when the specimens were in the clenched fist position: increased gap versus intact specimens equals 1.0 mm for DILC versus 3.7 mm for BC. The differences in diastasis were statistically significant between BC and DILC when the wrist was in extension, radial deviation, and clenched fist positions. After the scapholunate interosseous ligament was divided, the scaphoid flexed relative to the lunate. Both capsulodeses improved scapholunate alignment and there was a trend for DILC to correct the scapholunate angle more than BC. The results demonstrate that DILC is an attractive alternative to BC ex vivo. Because DILC does not tether the scaphoid to the distal radius, as BC does, improved wrist motion, especially flexion, might be possible in vivo. The use of DILC in the treatment of scapholunate dissociation warrants further investigation and clinical trials.

The radiological anatomy of the scaphoid. Part 2: Radiology

The complex shape of the scaphoid and its orientation within the carpus makes the radiological interpretation of scaphoid anatomy difficult. To improve our understanding of how the anatomy appears on plain X-ray, a study was performed using dry cadaver bones. Salient anatomical features were outlined using radiopaque markers, the bones set in wax blocks and the blocks X-rayed in the same axis as six "standard" scaphoid views. The pictures obtained were then compared with clinical X-rays.

Scapholunate distance in children

PURPOSE

To measure the scapholunate distance in normal wrists in a child population.

MATERIAL AND METHODS

In 79 children with unilateral wrist trauma boths wrists were radiographed in p.a. and lateral views.

RESULTS

The median scapholunate distance ranged from 9 mm in the 7-year-old to 3 mm in the 15-year-old children. Baseline values are presented.

Is this scapholunate joint and its ligament abnormal?

There is confusion in the literature with respect to evaluation of the scapholunate joint space and ligament. Because routine x-ray films of the wrist commonly do not profile the scapholunate joint perfectly, determination of the joint space width often is inaccurate. One method that invariably will allow a good profile of the scapholunate joint involves the use of fluoroscopically controlled views in different positions of the wrist. However, when abnormal width is suspected, in all examinations the wrist in question should be compared with the opposite wrist and the findings carefully correlated with clinical symptoms. Additional arthrographic findings, which have not been discussed in the literature before, are described. Midcarpal arthrography identifies and illustrates a variety of appearances of the scapholunate ligament. The reason for these different appearances and whether they are normal variations or pathologic findings is not known. This article is designed to stimulate further clinical and x-ray research to clarify normal and abnormal features of the scapholunate joint and ligament.