Biomechanical analysis of cadaveric wrists before and after MOTEC wrist arthroplasty using a hexapod robot.

This study compares wrist motion, biomechanical behaviour and radiographic parameters before and after total wrist arthroplasty using a fourth-generation spherical articulation prosthesis. A total of 10 cadaveric specimens were assessed using a hexapod Stewart platform robot. After arthroplasty, there were significant increases in both stiffness and phase angle of wrist motion across all planes of motion assessed. In three specimens, a sudden increase in moment was observed on load/displacement curves. Radiographically, carpal height increased by 14%, and the centre of rotation was displaced 11.1 mm proximally, 4.6 mm dorsally and 3.9 mm radially. This stretched the musculotendinous units, tightening the joint, while increasing the moment arm of the wrist flexors and decreasing the moment arm of the extensors, potentially important in the development of postoperative flexion contractures. Possible alterations in technique and/or implant design are considered to assist surgeons in achieving optimal clinical and survivorship outcomes.

Addressing the Central Band in Acute and Chronic Essex-Lopresti Injury: A Case Report and Technique Description.

CASE: A 34-year-old man was acutely treated with radial head arthroplasty and central band repair following Essex-Lopresti injury. A 38-year-old man presented with chronic longitudinal instability following failed radial head arthroplasty, which was performed for failed fixation. Treatment with revision radial head arthroplasty and central band reconstruction restored longitudinal stability. CONCLUSION: We have a low threshold to repair the central band in acute Essex-Lopresti injury with sufficient evidence of disruption. Nearly all chronic cases require central band reconstruction to restore longitudinal stability. We do not temporarily pin the DRUJ, and distal ulnar shortening is rarely indicated.

Lunate Fracture Morphology in Kienbock's Disease-A Computed Tomography Study.

Background The pathogenesis of Kienbock's disease is poorly understood. The coronal fracture line is acknowledged as a poor prognostic marker in the disease. Other fracture types in the Kienbock's wrist have subsequently been identified. Questions/Purposes The aim is to study the fracture morphology of the lunate in a cohort of patients using computed tomography. Methods Patient images were acquired using a set protocol with four-dimensional computed tomography scanning. Images were reviewed by two orthopaedic surgeons and a consultant radiologist. Static and dynamic images were assessed and a fracture map created. The relationship of fracture type to other parameters was then analyzed. Results Twenty-three patients were included in the study, including 11 males and 12 females, with a mean age of 43 years. Total frequency of fracture lines in the cohort was coronal - 26, proximal subchondral bone plate type - 24, avulsion - 19, sagittal - 16, and distal subchondral bone plate type - 11. There were statistically significantly more proximal than distal subchondral bone plate fractures ( p = 0.03), and more coronal fractures than distal subchondral bone plate fractures ( p = 0.01). There were statistically significantly more radiolunate ligament-avulsion types ( p <0.001) than other types. The sagittal fracture line through the lunate approximated closely to the ulnar edge of the capitate and the ulnar edge of the radius. Conclusion Study on the fracture morphology in the Kienbock's wrist has improved our understanding of the disease pathogenesis. Fracture lines may correspond to loading points, intrinsic and extrinsic ligament avulsions. These fracture types may play a role in disease progression and are important to identify when considering lunate salvage surgery.

Scapholunate instability: why are the surgical outcomes still so far from ideal?

The wrist is a universal joint with intrinsic and extrinsic ligaments that function and fail as ligamentous complexes. Those related to scapholunate instability (SLI) include the dorsal scapholunate complex (DSLC), volar radiolunate complex and scaphotrapeziotrapezoid complex. Together the DSLC, scaphoid and lunate create an 'acetabulum' for the capitate, with the dorsal intercarpal ligament being a labrum to contain the capitate. SLI results from failure of the DSLC, typically from its scaphoid attachments. Failure of the lunate and or triquetral attachments increases the instability. DSLC failure leads to radioscaphoid instability, which is the symptomatic clinical problem. SLI reconstruction with open surgery and trans-osseous tendon graft techniques have been challenging. We discuss a biological arthroscopic approach to identify, mobilize and debride the disrupted DSLC. This ligament/capsular/periosteum sheet is then advanced and secured to the debrided footprint. Thereby reconstituting the acetabulum, labrum and scaphoid stability.

Three-dimensional cortical and trabecular bone microstructure of the proximal ulna.

INTRODUCTION: The three-dimensional (3D) microstructure of the cortical and trabecular bone of the proximal ulna has not yet been described by means of high-resolution 3D imaging. An improved characterization can provide a better understanding of their relative contribution to resist impact load. The aim of this study is to describe the proximal ulna bone microstructure using micro-computed tomography (micro-CT) and relate it to gross morphology and function. MATERIALS AND METHODS: Five dry cadaveric human ulnae were scanned by micro-CT (17 µm/voxel, isotropic). Both qualitative and quantitative assessments were performed on sagittal image stacks. The cortical thickness of the trochlear notch and the trabecular bone microstructure were measured in the olecranon, bare area and coronoid. RESULTS: Groups of trabecular struts starting in the bare area, spanning towards the anterior and posterior side of the proximal ulna, were observed; within the coronoid, the trabeculae were orthogonal to the joint surface. Consistently among the ulnae, the coronoid showed the highest cortical thickness (1.66 ± 0.59 mm, p = 0.04) and the olecranon the lowest (0.33 ± 0.06 mm, p = 0.04). The bare area exhibited the highest bone volume fraction (BV/TV = 43.7 ± 22.4%), trabecular thickness (Tb.Th = 0.40 ± 0.09 mm) and lowest structure model index (SMI = - 0.28 ± 2.20, indicating plate-like structure), compared to the other regions (p = 0.04). CONCLUSIONS: Our microstructural results suggest that the bare area is the region where most of the loading of the proximal ulna is concentrated, whereas the coronoid, together with its anteromedial facet, is the most important bony stabilizer of the elbow joint. Studying the proximal ulna bone microstructure helps understanding its possible everyday mechanical loading conditions and potential fractures. LEVEL OF EVIDENCE: N.A.

Volar Lunate Facet Fractures of the Distal Radius: Fracture Mapping Using 3D CT Scans.

Background Fractures of the distal radius involving the lunate facet at the volar articular surface are unstable injuries and are usually managed operatively. Management of these fractures is challenging as our understanding of the exact fracture characteristics and associated injuries to the carpus is poor. Purpose This study aims to define the anatomy and associated injuries of lunate facet fractures using three-dimensional computed tomography (CT) scans and fracture mapping techniques. Methods A consecutive series of CT wrists was analyzed to identify intra-articular fractures involving the lunate facet at the volar distal radius. Fractures were mapped onto standardized templates of the distal radius using previously described fracture mapping techniques. We also identified instabilities of the carpus including volar carpal translation, ulnar translocation, scapholunate diastasis, and distal radioulnar joint (DRUJ) instability. Results We present 23 lunate facet fractures of the distal radius. The lunate facet fragment displaces in a volar and proximal direction and the lunate always articulates with the displaced fragment. The smaller fragments displace a greater amount, in a volar direction, with pronation. The fracture tends to occur between the origin of the short and long radiolunate ligaments. Conclusion Lunate facet fractures are frequently comprised of osteoligamentous units of the distal radius involving the short and long radiolunate ligaments and the radioscaphocapitate ligament. Assessment and management of volar carpal subluxation, scapholunate instability, ulnar translocation, and DRUJ instability should be considered. Clinical relevance Our mapping of these fractures contributes to our understanding of the anatomy and associated instabilities and will aid in surgical planning and decision making.

The Pathoanatomy and Biomechanics of Kienböck Disease.

Kienböck disease (KD) involves osseous, vascular, and chondral aspects of the lunate and wrist. We present our theories on the etiology and pathogenesis of the condition based on basic science models, seminal literature, personal case experience, and kinematic observations of the Kienböck wrist. Three phenotypes of Kienböck disease occur, and each tends to have different morphology, rates of progression, and disease pattern. The lunate fracture in KD is well-recognized but different fracture types can occur. Dynamic assessment of the Kienböck wrist allows assessment of the complex kinematics of KD. Disease onset and progression require a "perfect storm" of risk factors.

Preiser's Disease-Current Concepts of Etiology and Management.

The term Preiser's disease typically is used to describe idiopathic avascular necrosis of the scaphoid, but there have been a number of putative etiologies considered. It is rare and the natural history is not fully understood. Management of the condition should be based on patient factors as well as the stage of disease with regard to the scaphoid and the surrounding wrist. This chapter appraises the available evidence and aims to provide the reader with a framework to manage this rare condition.

Anatomical and Clinical Concepts in Distal Radius Volar Ulnar Corner fractures.

Background Volar ulnar corner fractures are a subset of distal radius fractures that can have disastrous complications if not appreciated, recognized, and appropriately managed. The volar ulnar corner of the distal radius is the "critical corner" between the radial calcar, distal ulna, and carpus and is responsible for maintaining stability while transferring force from the carpus. Description Force transmitted from the carpus to the radial diaphysis is via the radial calcar. A breach in this area of thickened cortex may result in the collapse of the critical corner. The watershed ridge (line) is clinically important in these injuries and must be appreciated during planning and fixation. Fractures distal to the watershed ridge create an added level of complexity and associated injuries must be managed. An osteoligamentous unit comprises bone-ligament-bone construct. Volar ulnar corner fractures represent a spectrum of osteoligamentous injuries each with their own associated injuries and management techniques. The force from the initial volar ulnar corner fracture can propagate along the volar rim resulting in an occult volar ligament injury, which is a larger zone of injury than appreciated on radiographs and computerized tomography scan. These lesions are often underestimated at the time of fixation, and for this reason, we refer to them as sleeper lesions. Unfortunately, they may become unmasked once the wrist is mobilized or loaded. Conclusions Management requires careful planning due to a relatively high rate of complications after fixation. A systematic approach to plate positioning, utilizing several fixation techniques beyond the standard volar rim plate, and utilizing fluoroscopy and/or arthroscopy is the key strategy to assist with management. In this article, we take a different view of the volar ulnar corner anatomy, applied anatomy of the region, associated injuries, and management options.

Arthroscopic Resection of Lunotriquetral Coalition.

Carpal coalition is a rare condition caused by a failure in the process of apoptosis. It is often incidentally diagnosed and seldomly symptomatic. The lunotriquetral joint is the most commonly affected joint, accounting for 90% of carpal coalitions. Minnaar classified the lunotriquetral coalitions into 4 types based on their type, extent, and associated abnormalities. Accurately classifying the coalition requires advanced imaging, and we show an example that includes 2-dimensional and 4-dimensional computed tomography and magnetic resonance imaging. Management of carpal coalitions include nonoperative and operative management. Splinting, anti-inflammatory drugs, hand therapy, activity modification, and steroid injections are all examples of nonoperative management. Operative management of coalitions in the carpus has historically been an arthrodesis whereas in the tarsal bones the gold standard is resection. Arthrodesis has a high complication rate and reduces wrist range of motion, whereas resection retains range of motion and allows the patient to return to activity sooner. We present 2 techniques of treating symptomatic carpal lunotriquetral coalition with arthroscopic resection.

Inferior angle of scapula fractures: A retrospective case series.

Background: Inferior angle of scapula fractures (IAS) are rare injuries that result from the periscapular shoulder muscles avulsing the inferior scapula tip. The aim of this study was to investigate the mechanisms of injury, investigations and treatment outcomes, as currently only case reports are available to guide management. Methods: Computered tomography (CT) images were reviewed to identify patients with an IAS fracture. Case notes were reviewed, and patients contacted to gather data relating to the injury, treatment and outcome. Results: Fourteen fractures were identified on CT. Five were missed on the initial radiograph. High energy fractures had an average age of 47.6 years, 90% were male. Low energy fractures had a mean age of 83.6 years 75% were female. All undisplaced fractures had a satisfactory outcome treated non-operatively. Three of six displaced fractures reported an unsatisfactory outcome with non-operative treatment. Subsequent surgical fixation resulted in resolution of symptoms. Conclusions: Inferior angle of scapula fractures are a rare injury that can result from high or low energy trauma. They are easy to miss on plain radiographs. Identification is important as displaced fractures can do poorly when treated non-operatively, but symptoms resolve with surgical fixation. Undisplaced fracture has a satisfactory outcome when treated non-operatively. Evidence: Level IV.

History of Wrist Arthroscopy.

Wrist arthroscopy has a rich history, drawing on contributions from around the world. Its foundation was laid in Japan with Kenji Takagi and Masaki Watanabe, who developed the arthroscope and the techniques for arthroscopy. Across several decades they advanced the optic and lighting technology, allowing the miniaturization which made wrist arthroscopy technologically feasible. A safe and standardized technique for wrist arthroscopy was evolved by Terry Whipple, Gary Poehling, and James Roth in the 1980s, and they shared this with their fellow surgeons through courses and publications. The techniques then spread across the world, leading to widespread uptake and exploration of new therapeutic possibilities. The worldwide spread of wrist arthroscopy was accelerated by the European Wrist Arthroscopy Society (EWAS), founded in 2005 by Christophe Mathoulin. The Asia Pacific Wrist Association (APWA), founded by PC Ho in 2015, also extended the progression of wrist arthroscopy. This article brings together this history and tells the global story of its development through the recollections of those involved. The manuscript includes some amazing videos of the early historical arthroscopy. There are also videos of Gary and Terry describing some of their special memories of the early politics, developments, and evolution of wrist arthroscopy.

The HAND-Q: Psychometrics of a New Patient-reported Outcome Measure for Clinical and Research Applications.

The perspective of the patient in measuring the outcome of their hand treatment is of key importance. We developed a hand-specific patient-reported outcome measure to provide a means to measure outcomes and experiences of care from the patient perspective, that is, HAND-Q. METHODS: Data were collected from people with a broad range of hand conditions in hand clinics in six countries between April 2018 and January 2021. Rasch measurement theory analysis was used to perform item reduction and to examine reliability and validity of each HAND-Q scale. RESULTS: A sample of 1277 patients was recruited. Participants ranged in age from 16 to 89 years, 54% were women, and a broad range of congenital and acquired hand conditions were represented. Rasch measurement theory analysis led to the refinement of 14 independently functioning scales that measure hand appearance, health-related quality of life, experience of care, and treatment outcome. Each scale evidenced reliability and validity. Examination of differential item functioning by age, gender, language, and type of hand condition (ie, nontraumatic versus traumatic) confirmed that a common scoring algorithm for each scale could be implemented. CONCLUSIONS: The HAND-Q was developed following robust psychometric methods to provide a comprehensive modular independently functioning set of scales. HAND-Q scales can be used to assess and compare evidence-based outcomes in patients with any type of hand condition.

Four-dimensional computed tomography scan for dynamic elbow disorders: recommendations for clinical utility.

BACKGROUND: Four-dimensional computed tomography (4D CT) is rapidly emerging as a diagnostic tool for the investigation of dynamic upper limb disorders. Dynamic elbow pathologies are challenging to diagnose, and at present, limitations exist in current imaging modalities. OBJECTIVE: We aimed to assess the clinical utility of 4D CT in detecting potential dynamic elbow disorders. METHODS: Twenty-eight elbow joints from 26 patients with symptoms of dynamic elbow pathology were included in this study. They were first assessed by a senior orthopedic surgeon with subsequent qualitative data obtained via a Siemens Force Dual Source CT scanner (Erlangen, Germany), producing two- and three-dimensional "static" images and 4D dynamic "movie" images for assessment in each clinical scenario. Clinical assessment before and after scan was compared. RESULTS: Use of 4D CT scan resulted in a change of diagnosis in 16 cases (57.14%). This included a change in primary diagnosis in 2 cases (7.14%) and secondary diagnosis in 14 cases (50%). In 25 cases (89.29%), the 4D CT scan allowed us to understand the pathological anatomy in greater detail which led to a change in the management plan of 15 cases (53.57%). CONCLUSION: 4D CT is a promising diagnostic tool in the management of dynamic elbow disorders and may be considered in clinical practice. Future studies need to compare it with other diagnostic modalities such as three-dimensional CT.

Regional differences in the three-dimensional bone microstructure of the radial head: implications for observed fracture patterns.

INTRODUCTION: A characterization of the internal bone microstructure of the radial head could provide a better understanding of commonly occurring fracture patterns frequently involving the (antero)lateral quadrant, for which a clear explanation is still lacking. The aim of this study is to describe the radial head bone microstructure using micro-computed tomography (micro-CT) and to relate it to gross morphology, function and possible fracture patterns. MATERIALS AND METHODS: Dry cadaveric human radii were scanned by micro-CT (17 µm/pixel, isotropic). The trabecular bone microstructure was quantified on axial image stacks in four quadrants: the anterolateral (AL), posterolateral (PL), posteromedial (PM) and anteromedial (AM) quadrant. RESULTS: The AL and PL quadrants displayed the significantly lowest bone volume fraction and trabecular number (BV/TV range 12.3-25.1%, Tb.N range 0.73-1.16 mm-1) and highest trabecular separation (Tb.Sp range 0.59-0.82 mm), compared to the PM and AM quadrants (BV/TV range 19.9-36.9%, Tb.N range 0.96-1.61 mm-1, Tb.Sp range 0.45-0.74 mm) (p = 0.03). CONCLUSIONS: Our microstructural results suggest that the lateral side is the "weaker side", exhibiting lower bone volume faction, less trabeculae and higher trabecular separation, compared to the medial side. As the forearm is pronated during most falls, the underlying bone microstructure could explain commonly observed fracture patterns of the radial head, particularly more often involving the AL quadrant. If screw fixation in radial head fractures is considered, surgeons should take advantage of the "stronger" bone microstructure of the medial side of the radial head, should the fracture line allow this.

Distal radius fractures.

The management of distal radius fractures has evolved considerably in the last two decades. Techniques and hardware have improved so much that the surgeon can usually assure good results in these debilitating fractures. Yet no one method can be used for all injuries, as the personality of each fracture demands a customized approach. Furthermore, what works in one age group may not work in another. For this reason, every available treatment has its own space in our options. The need for surgeons to be well versed in all techniques is critical. We offer a concise update of important evolutionary and current treatment guidelines for this common fracture.

The influence of fracture location and comminution on acute scaphoid fracture displacement: three-dimensional CT analysis.

We aimed to assess the influence of fracture location and comminution on acute scaphoid fracture displacement using three-dimensional CT. CT scans of 51 adults with an acute scaphoid fracture were included. Three-dimensional CT was used to assess fracture location, comminution and displacement. Fracture location was expressed as the height of the cortical breach on the volar and dorsal side of the scaphoid relative to total scaphoid length (%), corresponding to the fracture's entry and exit point, respectively. We found a near-linear relation between dorsal fracture location and displacement. As dorsal fracture location became more distal, translation (ulnar, proximal, volar) and angulation (flexion, pronation) of the distal fragment relative to the proximal fragment increased. Comminuted fractures had more displacement. Dorsal fracture location predictably dictates the direction of translation and angulation in displaced scaphoid fractures. Surgeon attention to dorsal fracture location can help identify displacement patterns and provide guidance in adequately reducing a displaced scaphoid fracture.Level of evidence: III.

Long-Term Outcome of Surgical Treatment for Kienböck Disease Using an Articular-Based Classification.

PURPOSE: The aim of this study was to report the outcomes of surgery using the Bain and Begg articular-based classification for the treatment of Kienböck disease. METHODS: We identified and followed patients who had surgery for Kienböck disease between 1995 and 2014. Assessment included functional scoring using a modification of the Gartland and Werley score, pain levels, and grip strength. RESULTS: Thirty-one patients were operated on for Kienböck disease between 1995 and 2014. Twenty-seven patients were assessed (12 men and 15 women). Mean age at the index procedure was 45.1 years (range, 20-82 years). Median follow-up after the index procedure was 10 years (range, 2-18 years). On the Bain and Begg classification, 5 patients had grade 0, 4 had grade 1, 5 had grade 2a, 10 had grade 2b, 1 had grade 3, and 1 had grade 4. The median pain visual analog scale improved from a preoperative score of 5 (interquartile range [IQR], 5-6) to a postoperative score of 2 (IQR, 0-3). The median functional scores from the modified Gartland and Werley score improved from 67 (IQR, 57.0-78.5) to 97 (IQR, 90.0-97.0). Eighteen out of 20 working patients returned to the same level of work. There was a significant improvement in power grip and tip pinch following surgery. One patient required a secondary salvage procedure. No patient required a full wrist fusion or arthroplasty. CONCLUSIONS: This study confirms that the Bain and Begg arthroscopic classification and an articular-based approach to Kienböck disease provide a high probability of good long-term relief of pain and a minimal chance of requiring a salvage procedure. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Kinematics of the wrist in Kienböck's disease: a four-dimensional computed tomography study.

We studied the kinematics of 20 wrists affected by Kienböck's disease using four-dimensional computed tomography (4-D-CT) scanning. Degenerative changes progressed from the lunate facet to the scaphoid fossa at the radiocarpal articulation, then involved the midcarpal joint. Lunate fracture types included coronal (14/20), sagittal (10/20) and ligament attachment-types (8/20). Findings specific to dynamic scanning included the nutcracker phenomenon (12/20), anterior radiolunate impingement (7/20), internal instability of the lunate (6/20), ulnar styloid triquetral impingement (3/20) and dynamic proximal row instability (2/20). Ulnocarpal translocation was found in 4/20 cases. Dynamic 4-D-CT has helped us to identify a subset of pathology in Kienböck's disease on assessment of static imaging. Better understanding of these phenomena can improve our understanding of symptoms and may help direct surgical treatment.Level of evidence: IV.