Wrist anatomy: incidence, distribution, and correlation of anatomic variations, tears, and arthrosis

Excision of the Distal Pole of the Scaphoid and the Midcarpal Joint

Background  Excision of the distal pole of the scaphoid is used to treat arthritis of the scaphotrapezial trapezoid (STT), radioscaphoid joint, and arthritis following scaphoid nonunion. Some patients develop midcarpal instability limiting utilization of this technique. Why some wrists develop postoperative instability while others do not, remains unclear. Purpose  To identify the wrists prone to developing midcarpal joint instability we evaluated the effect of midcarpal joint structure on force transfer through the wrist, we hypothesized that the force transfer will be further altered when a distal pole excision is performed and that midcarpal joint structure will affect force transfer. Materials and Methods  We used finite element analysis based on 19 computer tomography wrist scans. Nine type 1 (lunate has a facet with the capitate alone) and 10 type 2 (lunate has facets with both the capitate and hamate) models were prepared. A 200 N force was evenly split and applied to the dorsal crests of the trapezoid and capitate (100 N along each crest) to replicate the performance of a knuckle push-up. Displacement of the trapezoid, trapezium, scaphoid, capitate, and hamate was measured along each axis after the applied load. The simulation model was used to predict motion at the capitate and STT joint with excision of the distal pole. Results  Excision of the distal pole of the scaphoid affected the transfer of forces significantly (∼200% all bones in all directions) in all wrists. There are significant differences in force transfer between type 1 and type 2 wrists in the amount of force transferred (type 1 > type 2), in the percent difference from an intact wrist (type 1 > type 2) and in the direction of displacement (type 1 the bones moved in different directions while type 2 wrists moved as one block). Conclusion  This study suggests that midcarpal joint structure affects force transfer through the wrist and may predict wrist behavior following excision of the distal pole of the scaphoid. Specifically, type 1 wrists may be more prone to midcarpal joint collapse after excision. Level of Evidence : Level 1.

Development of a Finite Element Model of the Human Wrist Joint With Radial and Ulnar Axial Force Distribution and Radiocarpal Contact Validation

This study presents a comprehensive finite element (FE) model for the human wrist, constructed from a CT scan of a 68-year-old male (type 1 wrist). This model intricately captures the bone and soft tissue geometries to study the biomechanics of wrist axial loading through tendon-driven simulations and grasping biomechanics using metacarpal loads. Validation is carried out by assessing the radial and ulnar axial loading distribution, radiocarpal articulation contact patterns, and other standard finite element metrics. The results show radial transmission of the load, consistent with results from wrist finite element models conducted in the last decade and other experimental studies. Our results confirm the model's efficacy in reproducing key known biomechanical aspects, laying the groundwork for future investigations into ongoing wrist biomechanics challenges and pathology mechanism studies.

Midcarpal Impaction Syndromes as a Rare Cause of Ulnar-Sided Wrist Pain: A Review

Ulnar-sided wrist pain remains a commonly encountered diagnostic challenge, and its successful management requires a comprehensive understanding of the multiple conditions that can present with this symptom. Midcarpal impaction syndromes in the form of Hamato-lunate and Triquetro-hamate impingement have both previously been reported as rare potential causes of ulnar-sided wrist pain. Despite this, they remain poorly recognized and incompletely understood. This article reviews existing literature that describes the diagnosis and management of these clinical entities.

Management of Scaphotrapeziotrapezoid Osteoarthritis: A Critical Analysis Review

» The scaphotrapeziotrapezoid (STT) joint is a common location of degenerative osteoarthritis (OA) in the wrist.» STT OA may occur in isolation or with concomitant thumb carpometacarpal joint (CMCJ) OA or scapholunate advanced collapse (SLAC) and other wrist OA patterns.» Nonoperative management strategies include activity modification, bracing, anti-inflammatory medications, occupational therapy, and injections.» Surgical treatment may be determined by whether the STT OA occurs in isolation or with concomitant thumb CMCJ or SLAC OA and includes STT arthrodesis, distal scaphoid excision with or without interposition or implant arthroplasty, trapeziectomy with proximal trapezoid excision, four-corner fusion in combination with scaphoid/radial column excision, and proximal row carpectomy.

Force Transfer through the Scaphotrapeziotrapezoid (STT) Joint

Background  The scaphotrapeziotrapezoidal (STT) joint transfers forces to the proximal carpal row from the thumb and fingers. Clinically, STT joint osteoarthritis is frequently observed on plain radiographs though its role in the mechanics of the wrist joint remains unclear. Questions/Purposes  Our purpose was to use a model of normal wrist types, to predict STT motion upon load. Patients and Methods  Five normal computed tomography scans of a wrist type 1 and five wrist type 2 were used to model the wrist. A 200-N force was split and applied to the trapezoid and capitate to replicate forces during a knuckle pushup. The bony movement was predicted by the model as bony movement using finite element analysis. Results  We found differences in force transfer through the STT joint between the two wrist types when loading the index and middle fingers. Type 1 wrists moved quantitatively more anterior-posterior, type 2 wrists moved more medially-laterally and more proximally-distally. The trapezium in type 1 wrists moved more in the coronal plane than in type 2 wrists. The trapezoid moved more from distal to proximal in a type 2 wrist, p  = 0.03. Conclusion/Clinical Relevance  This study found differences in motion upon loading through the STT joint between type 1 and 2 wrists. Type 2 wrists moved more radially toward the proximal scaphoid and scapholunate ligament. This study may provide a mechanical basis for degenerative configurations. By linking observed patterns of degeneration to their mechanical causes we can aid in prevention of arthritis.

Comminuted lunate fracture combined with distal radius fracture and scaphoid fracture: A case report

RATIONALE

Incidence of lunate fractures is very low, less than 1% of all fractures. Lunate fractures generally come from high-energy injuries, often combined with other wrist fractures. Simple lunate fractures can be fixed with screws or Kirschner wires. However, Comminuted lunate fractures are difficult to reduce and fixe by conventional methods.

PATIENT CONCERNS

Here we report a 42-year-old male construction worker who was crushed by an excavator bucket and presented with comminuted lunate fracture combined with distal radius fracture and scaphoid fracture.

DIAGNOSES

Comminuted lunate fracture, distal radius fracture, and scaphoid fracture.

INTERVENTIONS

The posterior approach was used to reconstruct the radial lunate bone with polymethylmethacrylate cement, and cannulated screws were used to fix the scaphoid and distal radius fractures.

OUTCOMES

At the 3rd month after surgery, the movement of the right wrist joint improved. At the sixth month after surgery, the patient returned to the building site and began working at the same intensity as before the injury.

LESSONS

Although the incidence of comminuted lunate fractures is very low, they occur sometimes. For comminuted lunate fractures, early identification and intervention can preserve most of the function of the wrist joint.

Outcomes Following Surgical Treatment of Hamate Arthrosis Lunotriquetral Ligament Injuries

BACKGROUND

An institutional review board-approved study of the functional outcomes of patients after surgical treatment of hamate arthrosis lunotriquetral ligament tear (HALT) lesions was conducted.

METHODS

In all, 21 wrists in 19 patients underwent arthroscopic, open, or combined treatment of HALT lesions. Seven patients underwent isolated hamate debridement and 14 had concomitant procedures to address lunotriquetral pathology. Nineteen wrists underwent procedures to address additional pathology, including triangular fibrocartilage complex, ulnotriquetral ligament split, and scapholunate ligament injuries.

RESULTS

Mayo wrist scores increased from 54 to 71. Sixteen patients had no or mild pain postoperatively, compared with none preoperatively. When stratified by lunotriquetral interosseous ligament management, 75% of the limited treatment group (none or debridement) and 78% of the additional treatment group reported improved pain. Three patients underwent additional surgeries for persistent pain.

CONCLUSION

Resection of the proximal pole of the hamate can improve pain and function for patients with ulnar-sided wrist pain secondary to a HALT lesion. Concomitant wrist pathologies should be considered when determining treatment plans.

Long-term Results of the Treatment of Scapholunate Instability with Dynamic Extensor Carpi Radialis Brevis Tenodesis

Scapholunate dissociation is the most common form of carpal instability. This retrospective case series aimed to assess long-term results obtained by treating scapholunate instability with dynamic tenodesis using the entire extensor carpi radialis brevis tendon, which is detached from the base of the third metacarpal, rerouted in the third extensor compartment, and fixed at the distal portion of the scaphoid to maintain reduced rotatory subluxation.

Methods

Nine patients with scapholunate instability were treated. We reviewed eight patients with a mean follow-up of 12 years. One subgroup of four patients was affected by static scapholunate instability, and the other by dynamic scapholunate instability. Disability of the Arm, Shoulder, and Hand score, Patient Rated Wrist Evaluation score, modified Mayo score, and radiographs were used to determine functional and anatomical outcomes.

Results

Excellent functional results did not correlate with radiological outcome in patients with static scapholunate instability. In this subgroup, scapholunate angle and gap and radiolunate angle improved in average but remained in the pathologic range. In only one of these patients, osteoarthritis was observed. In the subgroup of patients affected by dynamic instability, very good functional outcomes correlate with radiological results, except in one patient who developed arthritic changes.

Conclusions

Dynamic tethering of the scaphoid with the extensor carpi radialis brevis tendon might be indicated in the treatment not only in patients affected by dynamic scapholunate instability but also in patients with static instability. Prospective studies with a larger number of patients are required to evaluate this method.

Hemi-hamate donor site morbidity and complications: a systematic review

Background

The hemi-hamate arthroplasty is utilised for the management of complex fracture-dislocations for injuries of the proximal interphalangeal joints (PIPJ) of the fingers. PIPJ outcomes are well described, including the post-operative range of motion, grip strength and osteochondral graft union. However, there is a paucity of evidence analysing the rate of donor site morbidity and complications. This systematic review aims to present the published morbidity of the donor site for the hemi-hamate arthroplasty.

Methods

A search was conducted in MEDLINE, Embase, Emcare, CINAHL and ProQuest Nursing and Allied Health databases from their inception which yielded 384 articles to be screened. Pertinent anatomy, harvesting techniques and post-operative donor site care of the hemi-hamate arthroplasty is reviewed.

Results

One hundred three cases of hemi-hamate arthroplasty were included in this review with seven (6.8%) complications presented, one of which required operative intervention.

Conclusion

Donor site morbidity resulting from harvesting an osteochondral graft for a hemi-hamate arthroplasty is low. The overall quality of evidence from the studies in this review is low, highlighting the need for further robust prospective trials.

Level of evidence

Not gradable.

Hamatolunate impingement syndrome in golfers: results of arthroscopic burring of the apex of the hamate

Hamatolunate impingement syndrome is an uncommon cause of ulnar-sided wrist pain in the general population. Often misdiagnosed and untreated by non-specialized physicians, it is an important source of chronic ulnar wrist pain in golfers. The purpose of this retrospective study was to report results of arthroscopic burring of the apex of the hamate for hamatolunate impingement, whether isolated or not, in golf players, with a minimum of six months follow-up. Fifteen golf players (10 amateur, 2 semi-professional and 3 professional players), aged 40-61 years, with ulnar carpal pain implicating hamatolunate impingement with Viegas type-II carpal configuration, were included. Treatment consisted in arthroscopic burring of the apex of the hamate. At an average follow-up of 11 months (range, 6-24 months), all patients were satisfied with functional results, except 1 with persistent pain and stiffness; 93% returned to sport to their prior level. Mean range of motion was improved by 17 ° for wrist flexion (range, 15 ° to 30 °) and 15 ° for wrist extension (range, 10 ° to 25 °). All patients except 1 recovered grip strength, improving from 27 kg (range, 12-53) preoperatively to 35 kg (range, 17-61) at last-follow-up, and ulnar-sided pain was alleviated during golf practice. Return to prior sport level was possible by 5.5 months for professional players and by 9 months for amateurs. Arthroscopic burring of the apex of the hamate provided good clinical results for function and pain, with fairly rapid return to sport. Hamatolunate chondritis does not always mean pathology but represents the natural progression of Viegas type II wrists.

Is DISI Deformity Related to Presence of a Medial Lunate Facet in Patients with Scapholunate Dissociation?

Background  Lunate morphology has been suggested to influence carpal kinematics. Purpose  We investigate a possible relation between presence of a medial lunate facet and dorsal intercalated segment instability (DISI) of the wrist in patients with a scapholunate (SL) dissociation. Methods  We retrospectively reviewed patients diagnosed with SL dissociation between 2000 and 2017. Lunate morphology was categorized based on radiographs and magnetic resonance imaging (MRI), as type I or II according to Viegas and Galley. DISI was defined as radiolunate angle > 15 degrees and SL instability as SL angle > 60 degrees. SL distance > 3 mm was considered as widening and carpal height ratio < 0.5 was considered as carpal collapse. We used descriptive statistics to report on SL instability and DISI in patients with Viegas type I and type II lunates. We calculated kappa to determine agreement between radiographs and MRI and to determine inter- and intraobserver agreement. Results  Of 119 patient files, 79 wrists met the inclusion criteria of which 25 were type I lunates and 54 type II. Similar spreading of the data of both groups was found regarding DISI, SL instability, and SL widening based on radiographic classification of the lunate, even after adding MRI findings. In the presence of carpal collapse, capitate-to-triquetrum distance was higher. We found a substantial inter- and intraobserver agreement for lunate classification. Conclusion  Our results suggest a similar prevalence of DISI deformity or enlarged SL angle in patients with type I or II lunate in presence of SL dissociation. The Viegas classification is a reliable and reproducible classification system. Level of evidence  This is a Level III, cross-sectional study design.

Ultrasound-guided injection of the pisotriquetral joint: technique and case series

PURPOSE

To describe our techniques for ultrasound-guided injection of the pisotriquetral joint (PTJ), and to report our experience in a case series.

METHODS

Between 7/1/14 and 11/30/20, we performed 42 injections in 33 patients with ulnar-sided wrist pain, referred by clinicians who suspected the PTJ as the pain generator. There were 16 males and 17 females, average age 46.7 years. The patients were positioned in one of five ways: sitting with the hand maximally supinated; sitting with the hand maximally pronated; supine with the elbow flexed across the chest and the ulnar aspect of the wrist facing upward; supine with the elbow flexed, the arm externally rotated, and the ulnar aspect of the wrist facing upward; prone with the symptomatic hand at their side and the ulnar aspect of the wrist facing upward.

RESULTS

The procedures were performed by any of twelve fellowship-trained musculoskeletal radiologists. Fifteen patients reported immediate relief of symptoms, including 6 patients whose pisotriquetral joints were normal sonographically. Four patients underwent subsequent surgical excision of their pisiforms and the fifth underwent arthroscopic debridement of the pisotriquetral joint.

CONCLUSION

Ultrasound is a facile imaging modality for guiding pisotriquetral injections, which may be accomplished with a variety of patient positions and injection techniques.

The triangular fibrocartilage complex in the human wrist: A scoping review toward uniform and clinically relevant terminology

The aim of this scoping review was to assess the composition, terminology, and anatomy of the triangular fibrocartilage complex (TFCC) of the wrist and propose unambiguous terminology regarding the individual components. The review was conducted according to the methodological framework by Arksey and O'Malley (International Journal of Social Research Methodology, 2005, 8, 19-32). Electronic databases were searched from inception until September 1, 2021 for original anatomical studies, using MeSH terms and keywords on terminology and anatomy of TFCC components. Studies using gross dissections or macro- or microscopic histology were included. Animal studies, fetal studies and studies with unknown disease status, were excluded. A total of 24 studies were included. The articular disc, the radioulnar ligaments, the meniscus homologue and the extensor carpi ulnaris tendon (sub)sheath were unanimously classified as TFCC components. One study did not include the ulnolunate and ulnotriquetral ligaments and only one study did include the ligamentum subcruentum. The largest disagreement existed regarding the inclusion of the ulnar collateral ligament. Terminological ambiguity was seen in "triangular fibrocartilage," "triangular ligament," "igamentum subcruentum," and the "proximal and distal lamina." Anatomical ambiguity existed especially regarding the radioulnar ligaments, the ulnar attachments of the TFCC and the ulnar collateral ligament. Definitions of the individual TFCC components are redundant, ambiguous, and ill-defined and therefore subject to different interpretations. In order to preclude confusion, consensus regarding terminology is recommended. We proposed a concise definition of the healthy TFCC that can be used as a starting point for future studies and current clinical practice.

Association of Lunate Morphology With Progression to Scaphoid Fracture Nonunion

Background: The purpose of our study was to review a series of patients with scaphoid fractures to determine whether there was an association between lunate morphology and progression to delayed union or nonunion when treated operatively or nonoperatively. Secondary aims included evaluation of the relationship between lunate morphology and scaphoid fracture location. Methods: A retrospective review of all patients with a diagnosis of scaphoid fracture was performed at our institution between 2014 and 2017. Medical records and radiographs were evaluated to determine lunate morphology, scaphoid fracture location, treatment, and time to union. Differences between groups were determined using χ² analysis with significance set at P <.05. Multiple logistic regression analyses were used to evaluate scaphoid union in the setting of lunate morphology when controlling for confounders. Results: A total of 169 patients were included; 45.0% (n = 76) of patients had type I lunate morphology, and 55.0% (n = 93) had type II. In all, 64.5% (n = 49) of patients with type I lunate and 68.8% (n = 64) with type II lunate had a fracture at the scaphoid waist. Among all patients with a scaphoid fracture, type II lunates were more likely than type I lunates to progress to nonunion when treated both operatively and nonoperatively (18.3% vs 4.0%, P = .0042). Lunate facet size was not shown to be a significant risk factor for nonunion among patients with a type II lunate (P = .4221). Conclusions: Patients with a scaphoid fracture and type II lunate morphology were more likely to progress to nonunion than patients with a type I lunate.

Surgical Treatment of Advanced Carpometacarpal Joint Arthritis: Trapeziectomy with Hematoma Arthroplasty

Osteoarthritis of the first carpometacarpal joint is common. When nonoperative measures fail, surgery may provide long-term pain relief. There are many surgical options in the management of carpometacarpal joint arthritis. Trapeziectomy with hematoma arthroplasty is technically simple, inexpensive, and has withstood the test of time. It is an excellent option for advanced carpometacarpal joint arthritis with multiple high-quality studies showing equivalent outcomes between this technique and ligament reconstruction tendon interposition techniques. This article reviews trapeziectomy with hematoma arthroplasty for treatment of carpometacarpal joint arthritis, including the indications for the procedure, the authors' preferred technique, and the current literature.

CT Scan versus Saline Load Test for Detection of Traumatic Wrist Arthrotomy

Background  Traumatic arthrotomy of the wrist is most commonly detected using the saline load test (SLT); however, little data exists on the effectiveness of the SLT to this specific joint. The use of computed tomography (CT) scan has been validated as an alternative method to detect traumatic arthrotomy of the knee, as the presence of intra-articular air can be seen when there is violation of the joint capsule. Question/Purpose  The purpose of this study was to determine the ability of CT scan to identify arthrotomy of the wrist capsule and compare the diagnostic performance of CT versus traditional SLT. Materials and Methods  Ten fresh frozen cadavers which had undergone transhumeral amputation were initially used in this study. A baseline CT scan was performed to ensure no intra-articular air existed prior to intervention. After baseline CT, an arthrotomy was created at the 6R radiocarpal portal site. The wrists then underwent a postarthrotomy CT to identify the presence or absence of intra-articular air. Following CT, the wrists were subjected to the SLT to detect the presence of extravasation from the arthrotomy. Results  Nine cadavers were included following baseline CT scan. Following arthrotomy, intra-articular air was visualized in eight of the nine cadavers in the postarthrotomy CT scan. Air was seen in the radiocarpal joint in eight of the nine wrists; midcarpal joint in seven of the nine wrists; and distal radioulnar joint in six of the nine wrists. All wrists (nine of the nine) demonstrated extravasation during the SLT. The mean volume of extravasation occurred at 3.7 mL (standard deviation = 2.6 mL), with a range of 1 to 7 mL. Conclusion  CT scan correctly identified eight of the nine simulated traumatic arthrotomies. Injection of 7 mL during the SLT was necessary to identify 100% of the arthrotomies. Clinical Relevance  CT scan is a sensitive modality for detection of traumatic arthrotomy of the wrist in a cadaveric model.

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.

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.

Facet Inclinations and Interfacet Angle of the Distal Radius on Posteroanterior Radiographs: Clinical Associations With 3 Carpal Pathologies

PURPOSE

The radiographic interfacet angle (IFA), scaphoid facet inclination (SFI), and lunate facet inclination (LFI) of the distal radius were measured in patients with 3 distinct wrist pathologies to determine whether there is an association between these radiographic measurements and these conditions.

METHODS

Posteroanterior wrist radiographs were compiled from patients with 3 types of common wrist pathologies (scaphoid waist fracture [n = 54], scapholunate [SL] dissociation [n = 23], and dorsal ganglion [n = 51]). The patients were all Caucasians aged 20 to 45 years who met strict radiographic criteria. The IFA, SFI, and LFI values of these patients were compared with those obtained from 400 normal wrist radiographs of subjects who met the same selection criteria.

RESULTS

In men with a scaphoid waist fracture, the IFA and SFI were significantly greater than in normal men, whereas the LFI was significantly lower. In the SL dissociation group, for all patients and for subgroups stratified according to sex, the IFA and SFI were significantly lower than in the normal matched groups. In the dorsal ganglion group, differences were found in the IFA and SFI for women, but not for men.

CONCLUSIONS

The facet orientations of the distal radius in patients with scaphoid fracture, SL dissociation, and dorsal ganglion differed from those in the normal population. The IFA alone is most likely to be associated with all 3 pathologies. The SFI and LFI are less likely to be associated with patients with carpal pathologies.

CLINICAL RELEVANCE

Patients with a greater IFA may be susceptible to scaphoid fractures when they fall on an overstretched hand. Patients with a smaller IFA may be susceptible to SL dissociation when they fall on an overstretched hand.

Ulnocarpal Impaction

Ulnocarpal impaction syndrome is a common cause for ulnarsided wrist pain caused by an abutment between the ulnar head and the lunotriquetral complex. This pain is typically triggered by load bearing and rotation of the forearm. Radiographic examination is often associated with positive ulnar variance and cysts in the lunate, edema of the ulnoproximal lunate is shown in MRI. Operative treatment aims to reduce load on the lunate, either by open ulnar shortening osteotomy or arthroscopic wafer procedure.

Extrinsic and Intrinsic Ligaments of the Wrist

Carpal stability depends on the integrity of both intra-articular and intracapsular carpal ligaments. In this review, the role of the radial-sided and ulnar-sided extrinsic and intrinsic ligaments is described, as well as their advanced imaging using magnetic resonance arthrography (MRA) and contrast-enhanced magnetic resonance imaging (MRI) with three-dimensional (3D) scapholunate complex sequences and thin slices. In the last decade, the new concept of a so-called "scapholunate complex" has emerged among hand surgeons, just as the triangular ligament became known as the triangular fibrocartilage complex (TFCC).The scapholunate ligament complex comprises the intrinsic scapholunate (SL), the extrinsic palmar radiocarpal: radioscaphocapitate (RSC), long radiolunate (LRL), short radiolunate (SRL) ligaments, the extrinsic dorsal radiocarpal (DRC) ligament, the dorsal intercarpal (DIC) ligament, as well as the dorsal capsular scapholunate septum (DCSS), a more recently described anatomical structure, and the intrinsic palmar midcarpal scaphotrapeziotrapezoid (STT) ligament complex. The scapholunate (SL) ligament complex is one of the most involved in wrist injuries. Its stability depends on primary (SL ligament) and secondary (RSC, DRC, DIC, STT ligaments) stabilizers.The gold standard for carpal ligament assessment is still diagnostic arthroscopy for many hand surgeons. To avoid surgery as a diagnostic procedure, advanced MRI is needed to detect associated lesions (sprains, midsubstance tears, avulsions and chronic fibrous infiltrations) of the extrinsic, midcarpal and intrinsic wrist ligaments, which are demonstrated in this article using 3D and two-dimensional sequences with thin slices (0.4 and 2 mm thick, respectively).

Accuracy of magnetic resonance imaging of the wrist for clinically important lesions of the major interosseous ligaments and triangular fibrocartilage complex; correlation with radiocarpal arthroscopy

OBJECTIVE

To demonstrate the utility of MRI in separating clinically relevant from minor or incidental lesions of the triangular fibrocartilage complex and the major interosseous ligaments in the wrist.

MATERIALS AND METHODS

In this retrospective study, we identified 89 patients and correlated MRI finding with subsequent arthroscopy. Triangular fibrocartilage complex abnormalities have been subdivided into disc lesions-central and radial-or ulnar-sided tears according to MRI appearances and surgical findings as the clinical and surgical approach is very different. Interosseous ligament tears were subdivided into partial or complete, highlighting the principle of recognising surgically relevant lesions.

RESULTS

For simple central to radial tears and perforations of the triangular fibrocartilage complex, MRI was 98.3% accurate. MRI identified all peripheral triangular fibrocartilage complex tears seen at arthroscopy; however, the specificity of 66.7% may reflect partly the use of arthroscopy limited to the radiocarpal joint. MRI proved 95.4% accurate for surgically relevant scapholunate interosseous ligament tears and was highly accurate at separating limited from complete lunotriquetral interosseous ligament tears showing 100% accuracy for complete tears.

CONCLUSIONS

The study shows excellent correlation between MRI and arthroscopic findings that determine surgical relevance with a very high sensitivity for triangular fibrocartilage complex lesions and accurate separation of minor versus surgically relevant ligamentous tears.

Lunate morphology: association with the severity of scapholunate ligament injuries and carpal instability patterns

Type II lunate has been associated with a lower incidence of dorsal intercalated segment instability (DISI) in the case of scapholunate dissociation. We aimed to evaluate the frequency of different lunate types and their influence on the prevalence and severity of scapholunate ligament (SLIL) injuries and the development of DISI. The surgical records of 414 arthroscopies were reviewed retrospectively. Lunate types were diagnosed based on radiograms and MRI examinations. The Type II lunate had a facet between hamate and lunate; in the Type I lunate, this facet is lacking. We additionally included the assessment of the capitate-triquetrum distance (CTD), which defines Type I, Intermediate, and Type II lunates. We adopted the DISI when the scapholunate angle was more than 80° and/or the radiolunate angle less than -15°. Fisher's exact test was applied to compare the distribution frequency of SLIL lesions and DISI deformity of patients with different lunate types. To quantify the inter- and the intra-rater reliability of lunate type assessment Cohen's kappa was calculated and, for CTD measurements, a Bland-Altman plot was created. Up to 77.1% patients had Type II lunates. Regarding MRI and CTD classification in patients with Type I lunates, Grade 4 SLIL injuries were more common than in those with Intermediate and Type II (p < 0.05). In the case of Grade 4 SLIL lesions, DISI was more common in patients with Type I lunates (p < 0.05). There were, however, only 25 patients with Type I lunates, and Grade 4 SLIL lesions according to MRI, and 6 according to CTD measurement.

Arthroscopic Pisiform Excision in Pisotriquetral Osteoarthritis Technique Using a Direct Pisotriquetral Portal

Pisotriquetral (PT) joint arthritis is a common cause of ulnar-sided wrist pain. Open pisiform excision is a well-established procedure and is indicated when the conservative treatment fails. Although arthroscopic visualization of the PT joint is part of the routine examination in a patient with ulnar-sided wrist pain, therapeutic arthroscopy of the PT joint is limited to one case in the literature through the standard dorsal portals. Arthroscopic pisiform excision is a novel technique described by the authors. The first aim of this procedure is pain relief maintaining wrist stability and strength. With this minimally invasive approach we believe that preserving the flexor carpi ulnaris and the PT ligament complex we maintain their biomechanical function, while at the same time, reducing scar tenderness and postoperative discomfort with better esthetic results and less recovery time. In addition to standard dorsal portals, a direct PT portal was used to have access to the PT space and as a working portal to complete the pisiform excision.

Relative Prevalence of and Factors Associated with Anxiety and Depression in Degenerative Triangular Fibrocartilage Complex Lesion Patients - a Casecontrol Study

Triangular fibrocartilage complex (TFCC) lesions are a common cause of ulnar wrist pain. Data, including mental status assessment, were prospectively collected from patients who underwent arthroscopy. The HADS was used to assess the prevalence of depression and anxiety. Patients with degenerative TFCC lesions were at an increased risk of anxiety and depression. Early screening for anxiety and depression in degenerative TFCC lesions patients should be recommended.

Locked Wrist: A Case Report and Literature Review on Pisotriquetral Loose Bodies

Background  Pisotriquetral (PT) loose bodies have been described in the literature only a few times as case reports. While PT pathology remains the differential for ulnar-sided wrist pain, it can often be difficult to diagnose, as symptoms can be variable and radiographic imaging may be negative for any findings. Case Description  A 24-year-old major league baseball player presented with pain and locking of his wrist during follow through of his bat swing. Plain radiographic imaging, as well as computed tomography (CT) imaging, was negative for any pathology. Dynamic magnetic resonance imaging (MRI) demonstrated a loose body which entered the PT joint when the wrist was moved into a flexed position. This caused entrapment of the loose body and locking of the wrist. Literature Review  A total of 17 reported patients in the literature have been diagnosed with a PT loose body. The clinical examination findings, radiographic findings, and surgical findings are reviewed. Case Relevance  PT loose bodies can present a challenging clinical picture to diagnose. The purpose of this case report is to review the appropriate clinical workup, including common examination findings and advanced imaging techniques, to help the clinician with the diagnosis.

Introducing the “SOAC Wrist”: Scaphotrapeziotrapezoid Osteoarthritis Advanced Collapse

Despite being the second most common osteoarthritis of the wrist, little is known about scaphotrapeziotrapezoid osteoarthritis. Not all patients with this type of osteoarthritis have symptoms, and, even in those symptomatic patients, the intensity of the complaint is not proportional to the severity of the degeneration. In symptomatic patients, when the conservative treatment fails, grading classifications to help define the surgical treatment are solely based on the joint characteristics, and fail to assess the rest of the carpus.

In general, most carpal degenerative processes show the same evolution pattern, which varies according to the initial injury, along with the type of deformity and the inherent instabilities. Thus, we hypothesize that the degenerative evolution due to primary osteoarthritis of the scaphotrapeziotrapezoid joint also follows a logical evolutionary sequence, similar to the one that occurs in cases of scapholunate advanced collapse (SLAC), scaphoid nonunion advanced collapse (SNAC), scaphoid malunion advanced collapse (SMAC), and scaphoid chondrocalcinosis advanced collapse (SCAC), thus resulting in scaphotrapeziotrapezoid osteoarthritis advanced collapse (SOAC). We have divided the SOAC into three groups, and considered that their treatment shall be guided by the evolutionary stage of the disease, and not by the surgeon's preferred technique.

What Is the Effect of the Ulnar-Plus Variance on the Outcomes of Arthroscopic Repair of the Peripheral Ulnar-Side Triangular Fibrocartilage Complex Tear?

PURPOSE

To compare the outcomes of arthroscopic repair of peripheral ulnar-side triangular fibrocartilage complex (TFCC) tears between patients with and without ulnar-plus variance (UPV) and to identify factors associated with index surgery failure in these patients.

METHODS

We retrospectively analyzed 50 consecutive patients who underwent arthroscopic repair of peripheral ulnar-side TFCC tears from June 2014 to February 2018. We selected patients who were aged at least 18 years and underwent arthroscopic repair of peripheral ulnar-side TFCC tears. We excluded those with a fractured or dislocated wrist, ulnar impaction syndrome, degenerative or inflammatory arthritis of the wrist, or neurologic conditions that affect upper-extremity function, as well as those who received less than 12 months' follow-up. We evaluated the patients with a visual analog scale for pain in 3 domains (overall, with hard work, and at rest), the Patient-rated Wrist Evaluation, range of motion, and grip strength. Clinical outcomes and arthroscopic findings were compared between patients with and without UPV (UPV group and non-UPV group, respectively). We calculated the relative risk and 95% confidence interval for younger age (<30 years), sex, UPV, and coexisting degenerative central TFCC tear (type 2 tear) to determine the risk factors for arthroscopic repair failure.

RESULTS

No significant differences were noted between the 2 groups regarding visual analog scale pain and Patient-rated Wrist Evaluation scores and rates of excellent or improved outcomes (P > .05). Arthroscopic repair failure was found in 4 patients. A coexisting type 2 TFCC tear was the only significant risk factor (relative risk, 49.5; 95% confidence interval, 2.94-83.96; P = .007) for arthroscopic repair failure.

CONCLUSIONS

UPV did not significantly affect the outcomes of arthroscopic repair of peripheral ulnar-side TFCC tears. However, coexisting type 2 TFCC tears significantly increased the risk of index surgery failure in these patients.

LEVEL OF EVIDENCE

Level IV, prognostic study.

A New Technique for Radiographic Visualization of the Scaphotrapeziotrapezoid Joint

Standard radiographs of the wrist do not provide adequate visualization of the scaphotrapeziotrapezoid joint. A radiographic technique that provides an improved and more complete visualization of the joint compared with routine views is described. [Orthopedics. 2020; 43(2):e123-e124.].

Performance evaluation of surgical techniques for treatment of scapholunate instability in a type II wrist

We investigated the performance of three tenodesis techniques, modified Brunelli, Corella, and scapholunate axis (SLAM) methods in repairing scapholunate interosseous ligament (SLIL) disruption for a type II wrist using finite element-based virtual surgery and compared the results with those of a previous investigation for a type I wrist. In addition, a comparison of the carpal mechanics of type I and type II wrists was undertaken in order to elucidate the difference between the two types. For the type II wrist, following simulated SLIL disruption, the Corella reconstruction technique provided a superior outcome, restoring dorsal gap, volar gap, and SL angle to within 3.5%, 7.1%, and 8.4%, respectively, of the intact wrist. Moreover, application of the ligament reconstruction techniques did not significantly alter the motion pattern of the type II and type I wrists. For the type I wrist, SLIL disruption resulted in no contact between scaphoid-lunate cartilage articulation, whereas for the type II wrist, some contact was maintained. We conclude that the Corella ligamentous reconstruction technique is best able to restore SL gap, angle, and stability following SL ligament injury for both type II and type I wrists and is able to do so without altering wrist kinematics. Our findings also support the view that type I wrists exhibit row behaviour and type II wrists column behaviour. In addition, our analysis suggests that the extra articulation between the lunate and hamate in a type II wrist may help improve stability following SL ligament injury.

Dart thrower's motion and the injured scapholunate interosseous ligament: A scoping review of studies examining motion, orthoses, and rehabilitation

STUDY DESIGN

Scoping review.

INTRODUCTION

Dart thrower's motion (DTM) of the wrist primarily arises from the midcarpal joint, and minimizes stress to the scapholunate interosseous ligament (SLIL). After SLIL injury or surgery, early controlled DTM may reduce the effects of prolonged immobilization, while protecting SLIL integrity.

PURPOSE OF THE STUDY

To summarize the literature on the effects of DTM on the injured and surgically repaired SLIL and the extent to which various DTM orthotic designs promote SLIL recovery.

METHODS

A systematic literature search was conducted within 6 databases for articles published between 2003 and March 2018. Eligible studies examined DTM in the context of SLIL injury or repair. Relevant data were extracted by 2 independent reviewers.

RESULTS

Of 425 identified articles, 15 were eligible for inclusion. Five biomechanical studies examined the influence of DTM on the injured SLIL, whereas 5 articles described DTM orthotic designs. Also included were five articles that reported outcomes when DTM was used in the rehabilitation protocol.

DISCUSSION

The included studies suggest limiting end ranges of DTM in the injured/repaired SLIL, while blocking orthogonal plane movements. Custom orthotic designs may accomplish this goal. DTM has been used in comprehensive therapy programs in small case studies reporting short-term and intermediate clinical outcomes.

CONCLUSIONS

Caution should be exercised with using DTM on the torn SLIL as gap increases, particularly at the end-range motion. Orthosis designs have potential to limit this motion to midrange, while allowing early movement. Further high-level research is needed to understand the influence of DTM on injured and postsurgical populations.

Midcarpal Structure Effect on Force Distribution through the Radiocarpal Joint

Background  Wrist structure is complicated by distinct anatomical patterns. Previous studies defined radiographic wrist types based on lunate and capitate shape within the midcarpal joint. We hypothesized that these disparate structural patterns will transfer forces differently through the wrist. Objective  This study aims to correlate force transferred to the distal radius and ulna with morphological measurements in cadaver arms. Methods  Radiographs from 46 wrists, previously tested for force transfer between the radius and ulna, were examined. The percentage of compressive force through the distal ulna was determined by mounting load cells to the radius and ulna, while 22.2 Newton (N) tensile forces were individually applied to multiple tendons. Each wrist was tested in a neutral flexion-extension and radial-ulnar deviation position. Results  Wrist type and lunate type were associated with percentage of force transfer through the ulna ( p  = 0.002, p  = 0.0003, respectively). Percentage of force transfer was correlated with capitate circumference ( p  = 0.02, r  = 0.34). Conclusions  This study supports distinct force transfer between morphological wrist types. Clinical Relevance  Understanding the mechanical significance of different structural variations in the wrist bones will improve our ability to understand wrist function and the distinctive development of wrist pathology. Level of Evidence  This is a Level II study.

Evaluation and Management of Scaphoid-Trapezium-Trapezoid Joint Arthritis

Degenerative arthritis at the articulation of the scaphoid, trapezium, and trapezoid (STT or triscaphe joint) is a common degenerative disease of the wrist. Pain and weakness with grip strength reduction and functional limitations when performing routine daily tasks are common complaints of patients with STT arthritis. Initial conservative treatments for STT arthritis include splinting, bracing, activity modification, anti-inflammatory medication, and steroid injections for pain relief. Failure of conservative treatment is the main indication for surgery, which may include distal scaphoid excision, with or without filling of the void after excision, trapeziectomy, STT arthrodesis, or STT implant arthroplasty.

Analysis of Radiographic Relationship between Distal Radius, Ulna, and Lunate

Background  Wrist anatomy variability is associated with differing susceptibility to pathology. For example, a flat radial inclination is associated with Kienbock's disease. Lunate facet inclination (LFI) also exhibits variability. Its relationship with other wrist features is poorly documented. Purposes  We tested the hypothesis that high LFI is associated with increased uncovering of the lunate, negative ulnar variance (UV), and type 2 lunates to balance forces across wrists. Methods  In total, 50 bilateral and 100 unilateral wrist posteroanterior radiographs were reviewed. Lunate type, lunate uncovering index (LUI), lunate tilting angle (LTA), UV, and sigmoid notch angle (SNA) were measured, and correlation with LFI was assessed on 150 right wrist radiographs followed by an assessment of differences based on lunate morphology. Symmetry of 50 bilateral wrists was assessed. Results  There was no correlation of LFI with lunate morphology, LUI, and LTA. There was a low correlation of LFI with SNA and UV. There was an inverse relationship between UV and SNA. Wrists with type 2 lunates had more oblique sigmoid notches and higher LTA in comparison to wrists with type 1 lunates. Side-to-side comparison revealed strong correlation except for LUI, which exhibited moderate correlation. Conclusions There is no correlation between LFI, LUI, and lunate morphology. Type 2 lunates are associated with higher LTA and more oblique SNA. Wrists were symmetrical. Clinical Relevance  Factors other than lunate morphology are essential in balancing forces across wrists. A better understanding of soft tissue and other factors will improve the understanding of wrist biomechanics and pathology. Contralateral wrist radiographs can guide reconstructive surgery.

Radiographic prediction of lunate morphology in Asians using plain radiographic and capitate-triquetrum distance analyses: reliability and compatibility with magnetic resonance arthrography (MRA) findings

Background

The purpose of this study was to examine the reliability of plain radiographic methods of determining the lunate type and its compatibility with magnetic resonance arthrography (MRA) findings.

Methods

Plain radiographs of a total of 150 wrists were reviewed by three observers. Lunate types were evaluated using both conventional posteroanterior (PA) radiographic analysis and the capitate-triquetrum distance (CTD) analysis. Cohen kappa and Fleiss kappa statistics were used to estimate intra- and inter-observer reliabilities. Compatibility with the MRA findings, as assessed by each observer, was investigated.

Results

The overall intra-observer reliability was 0.517 for the analysis and 0.589 for the CTD analysis. The overall inter-observer agreement was 0.448 for the PA radiographic analysis and 0.581 for the CTD analysis. The PA radiographic analysis and MRA findings for the detection of medial lunate facets were compatible in 119 of the 150 patients (79.3%). Twenty-eight (90.3%) of the 31 incompatible wrists had a medial facet on MRA (Type II), which was not detected in the PA radiographic analysis. In the CTD analysis, the results for 27 of 29 Type II lunates (93.1%) and 39 of 45 Type I lunates (86.7%) were compatible with the MRA.

Conclusions

This study suggests that predicting the lunate type by plain radiographs alone is insufficient, as both radiographic analyses showed moderate intra- and inter-observer reliabilities. Although both radiographic analyses showed good compatibility with the MRA for Type II lunates, clinicians should be alert to undetected medial facets in Type I lunates on PA radiographic analysis.

The Effect of Lunate Morphology in Carpal Disorders: Review of the Literature

Variation in lunate morphology can exist based on the absence (Type I) or presence (Type II) of medial facet on the distal articular surface of the lunate that contacts the proximal pole of the hamate. This additional lunatohamate articulation can affect load transmission across the radiocarpal joint and exert an influence on carpal kinematics. A Type II lunate is protective against carpal instability patterns associated with scaphoid nonunions and scapholunate dissociations. It may also play a role in the progression of carpal collapse that occurs in Kienböck disease. This review summarizes the effect of lunate morphology in the outcomes of non-operative and operative treatment of carpal disorders.

An Anthropometric Assessment of the Proximal Hamate Autograft for Scaphoid Proximal Pole Reconstruction

PURPOSE

Fragmentation of the scaphoid proximal pole secondary to avascular necrosis presents a difficult reconstructive problem. This anthropometric study assesses the utility of the ipsilateral proximal hamate for complete osteochondral scaphoid proximal pole reconstruction.

METHODS

Twenty-nine cadaveric specimens underwent computed tomography scanning and 3-dimensional reconstruction of the carpus and distal radius. Scaphoid height was measured and a third of its height was used to simulate resection of the proximal scaphoid pole and extent of hamate autograft required. The proximal scaphoid and hamate were divided into 6 sections, and compared using an iterative point-to-point distance algorithm. Average distance between the scaphoid and the hamate surfaces was determined. An interbone algorithm was used to assess radioscaphoid joint congruency and articular contact surface of the native scaphoid compared with the scaphoid reconstructed with hamate autograft.

RESULTS

The mean height of scaphoid proximal pole excision and proximal hamate autograft height was 9.3 mm. Comparing the morphology of the native scaphoid and hamate autografts, the absolute distances were the largest in the volar radioscaphoid, dorsal radioscaphoid, and dorsal scaphocapitate segments. Without osteotomy, the hamate autograft may cause impaction in the dorsal-radial aspect of the distal radius. The hamate autograft also shifted the articular contact point of the radioscaphoid joint toward the dorsal-radial position. Nine hamate autografts were classified as poor-fitting. Poor-fitting specimens had a greater radial styloid to distal radioulnar joint distance. These specimens also had wider hamates and scaphoids in the radial-ulnar dimension and wider scaphoids in the volar-dorsal dimension. Lunate type did not correspond to anthropometric fit.

CONCLUSIONS

The proximal hamate osteochondral graft was poor fitting in 31% of cases (9 of 29 specimens). Wrists with radial-ulnar hamate width less than 10 mm, radial-ulnar scaphoid width less than 10 mm, and volar-dorsal scaphoid width less than 16 mm demonstrate better anthropometric fit.

CLINICAL RELEVANCE

This study provides an anthropometric assessment of the recently described proximal hamate autograft, a new bone graft option for proximal scaphoid pole reconstruction.

Association of Lunate Morphology With Carpal Instability in Scapholunate Ligament Injury

BACKGROUND

We examined the relationship between lunate morphology (type 1 without a medial facet; type II with a medial facet) and dorsal intercalated segmental instability (DISI) in patients with scapholunate ligament injuries. We tested the primary null hypothesis that there is no relationship between lunate morphology and development of DISI. Secondary analysis compared the agreement of classifying lunate morphology based on the presence of a medial lunate facet, capitate-to-triquetrum (CT) distance, and magnetic resonance imaging (MRI).

METHODS

We performed a retrospective chart review of patients with known scapholunate ligament injuries from 2001 to 2016. Posterior-anterior radiographs and MRI, when available, were evaluated. CT distances were measured as a secondary classification method. DISI and scapholunate instability were determined as radiolunate angle >15° and scapholunate angle >60°, respectively. Differences between groups were determined using chi-square analysis with significance set at P < .05. Agreement between plain radiographs, MRI, and CT distance was calculated using the kappa statistic.

RESULTS

Our search found 58 of 417 patients who met inclusion criteria; 41 of 58 had type II and 17 of 58 had type I lunates. There was no significant difference between groups in regard to DISI or scapholunate instability. Subanalysis using MRI alone or correcting any discrepancy between plain film and MRI classification, using MRI as the standard, found no difference between groups in regard to DISI or scapholunate instability.

CONCLUSIONS

In patients with scapholunate ligament injuries, there are no differences in the development of DISI or scapholunate instability between patients with type I and type II lunates.

Anatomy and injuries of the pediatric wrist: beyond the basics

Ligamentous injuries of the pediatric wrist, once thought to be relatively uncommon, are increasingly recognized in the context of acute high-energy mechanism trauma and chronic axial loading, including those encountered in both recreational and high-performance competitive sports. Recent advances in MR-based techniques for imaging the pediatric wrist allow for sensitive identification of these often radiographically occult injuries. Detailed knowledge of the intrinsic and supportive extrinsic ligamentous complexes, as well as normal developmental anatomy and congenital variation, are essential to accurately diagnose injuries to these structures. Early identification of ligamentous injury of the pediatric wrist is essential within the conservative treatment culture of modern pediatric orthopedics because treatment of these lesions often necessitates surgery, and outcomes often depend on early and sometimes aggressive intervention. In this article, we review MR arthrogram technique and pediatric wrist anatomy, and correlate appearances on MR and selected ligamentous pathologies of the pediatric wrist.

A three-dimensional printed patient-specific scaphoid replacement: a cadaveric study

We present our first cadaveric test results of a three-dimensional printed patient-specific scaphoid replacement with tendon suspension, which showed normal motion behaviour and preservation of a stable scapholunate interval during physiological range of motion.

Morphological Associations between the Distal Radioulnar Joint and the Lunate

Background  Variations in morphology of the carpal bones have been described. Their implication in wrist disease and specific kinematic features has been recognized, and a better knowledge of these variations is essential. Questions/Purpose  To radiographically determine any association between the morphological variations of the distal radioulnar joint (DRUJ) and the lunate bone. Materials and Methods  Radiographs of 100 wrists of patients presenting to the emergency department with wrist pain and referred to our outpatient clinic were retrospectively reviewed for DRUJ inclination, ulnar variance, and radiocarpal and midcarpal morphology of the lunate. Results  There were 51 females and 49 males, mean age 51.2 years (range: 21-94). There was a statistically significant association between the DRUJ inclination and the morphology of the radiocarpal side of the lunate ( p  < 0.001). The mean values of ulnar variance changed according to DRUJ inclination and the radiocarpal side of the lunate ( p  < 0.001) but not according to the midcarpal side of the lunate. There was no significant association between the morphology of the DRUJ and the midcarpal side of the lunate or between the midcarpal and the radiocarpal morphology of the lunate. Conclusion  This study demonstrated a statistically significant association at the radiocarpal level between the DRUJ inclination, ulnar variance, and the morphology of the lunate. No association was found with the morphology of the midcarpal side of the lunate. Accordingly, a classification of these carpal associations is proposed, highlighting seven main wrist configurations. Clinical Relevance  These associations can guide future studies of wrist kinematics.

Lunate morphology as a risk factor of idiopathic ulnar impaction syndrome

AIMS

Positive ulnar variance is an established risk factor for idiopathic ulnar impaction syndrome (UIS). However, not all patients with positive ulnar variance develop symptomatic UIS and other factors, including the morphology of the lunate, may be involved. The aim of this study was to clarify the relationship between lunate morphology and idiopathic UIS.

PATIENTS AND METHODS

A cohort of 95 patients with idiopathic UIS (UIS group) was compared with 95 asymptomatic controls with positive ulnar variance. The shape of the lunate was measured using the capitate-triquetrum distance (CTD), ulnar coverage ratio (UCR), radiolunate distance and radiolunate angle. The association of radiographic parameters and lunate types with the development of UIS was investigated in univariable and multivariable analyses. Receiver operating characteristic curves were used to estimate a cutoff for any statistically significant variables.

RESULTS

The proportion of type II lunates, which have a medial hamate facet, were significantly higher in the UIS group than in the control group in the univariable analysis (p = 0.001). CTD (odds ratio (OR) 1.52; 95% confidence interval (CI) 1.11 to 2.06; p = 0.008) and UCR (OR 44.78; 95% CI 5.35 to 374.90; p = 0.002) showed a positive association with UIS in the multivariable analysis. Estimated cutoff values were 2.5 mm for the CTD (area under the curve (AUC) = 0.65) and 0.4 for the UCR (AUC = 0.64).

CONCLUSION

The proportion of type II lunates was greater in the UIS group than in the control group. A large UCR, which represents the broad base of the lunate, was positively associated with the development of idiopathic UIS. Cite this article: Bone Joint J 2017;99-B:1508-14.

A wearable hand gesture recognition device based on acoustic measurements at wrist

This paper investigates hand gesture recognition from acoustic measurements at wrist for the development of a low-cost wearable human-computer interaction (HCI) device. A prototype with 5 microphone sensors on human wrist is benchmarked in hand gesture recognition performance by identifying 36 gestures in American Sign Language (ASL). Three subjects were recruited to perform over 20 trials for each set of hand gestures, including 26 ASL alphabets and 10 ASL numbers. Ten features were extracted from the signal recorded by each sensor. Support Vector Machine (SVM), Decision Tree (DT), K-Nearest Neighbors (kNN), and Linear Discriminant Analysis (LDA) were compared in classification performance. Among which, LDA offered the highest average classification accuracy above 80%. Based on these preliminary results, our proposed technique has exhibited a promising means for developing a low-cost HCI.

Clinical outcomes of proximal row carpectomy by preoperative midcarpal joint morphological classification: Viegas type I versus type II

The midcarpal joint can be classified into two anatomical types - Viegas type I and Viegas type II - based on the absence or presence of a medial facet for the hamate on the lunate (lunohamate facet). Type I is associated with a round capitate shape, which theoretically allows better congruence with the lunate fossa of the distal radius following proximal row carpectomy (PRC). This morphological feature has never been considered as a predictive factor of clinical outcome for this surgical procedure. This study aimed to compare the clinical and radiological outcomes of the two Viegas types following PRC. A retrospective single-center study was carried out on patients who underwent PRC for wrist osteoarthritis. Minimum follow-up was 2 years. Lunate type was determined based on preoperative CT arthrography. The clinical evaluation included range of motion (ROM) and strength as well as the functional DASH, Mayo Wrist scores and a VAS for pain. The outcome of radiocapitate osteoarthritis was assessed on plain radiographs. Forty patients were reviewed with a mean follow-up of 57 months. Twenty-one Viegas type I and 19 Viegas type II were identified on preoperative CT arthrography. The etiologies included 23 SLAC wrists (12 Viegas type I, 11 type II), 8 SNAC wrists (4 Viegas type I, 4 type II), 6 cases of Kienböck's disease (3 type IIIa, 3 type IIIb with 3 Viegas type I and 3 type II), 1 Preiser's disease and 2 cases of transscaphoid perilunate dislocation of the carpus. Patients with a Viegas type I lunate had significantly greater flexion-extension ROM: 83.5° vs. 71° (P=0.04) and radial deviation: 12° vs. 7° (P=0.013) than those with Viegas type II. However, three cases of complex regional pain syndrome (CRPS) were reported in the Viegas type II group vs. zero in the Viegas type I group. There were no differences between the two groups in terms of strength, functional scores or VAS pain. The outcome of radiocapitate osteoarthritis was similar in both groups. Considering the number of CRPS cases in the Viegas type II group and similar functional results in both groups, the worse outcomes of the Viegas type II patients in terms of ROM cannot be considered as clinically relevant. This comparative study does not provide a reasonable basis for concluding that Viegas type I patients are better candidates for PRC than Viegas type II patients.

Scapholunate dissociation; diagnostics made easy

Scapholunate dissociation (SLD) is a form of carpal instability, caused by rupture of the scapholunate ligament (SLL) the secondary stabiliser of the scapholunate (SL) compartment. SLD can cause osteoarthritis of the wrist. Recently a study was published that shows cineradiography to be an excellent radiological imaging technique for diagnosing SLD at a tertiary centre for hand and wrist surgery [1]. As the quality of these results can be influenced by the expertise of the operator and observer of the cineradiographic studies, the aim of this study was to determine if these results were reproducible at a secondary centre for hand and wrist surgery with less expertise in wrist cineradiography. All cineradiographic studies carried out during a 10-year period were obtained. All patients who underwent the gold standard procedure (arthroscopy/arthrotomy) after cineradiography were included, a total of 50 patients. The diagnostic accuracy of detecting SLD by both cineradiography and conventional radiography was calculated. Cineradiography had a high diagnostic accuracy, while the accuracy for conventional radiography was average. When all wrists with an SL distance ≥3mm were excluded (static SLD), diagnostic accuracy for conventional radiography dropped even lower, while accuracy for cineradiography remained high. These results are comparable with published accuracy rates and show that cineradiography has a high diagnostic value for detecting SLD and do not seem to be influenced by the operator or observer of the cineradiographic studies.

Biomechanical Comparison of Open and Arthroscopic Transosseous Repair of Triangular Fibrocartilage Complex Foveal Tears: A Cadaveric Study

PURPOSE

To biomechanically compare the stability between open repair and arthroscopic transosseous repair technique for reattachment of the foveal triangular fibrocartilage complex (TFCC). We also evaluated the feasibility of a new aiming device for the creation of 2 bone tunnels simultaneously during the arthroscopic technique.

METHODS

Six matched pairs of fresh-frozen forearm cadaver specimens were prepared for testing. Group I specimens were treated by open repair with suture anchor. Group II specimens were treated by arthroscopic transosseous suture with a new aiming device. Before and after disruption of the TFCC fovea and after its repair, dorsal and palmar translation of the ulna was measured in both groups in response to a load (3 kg) applied in the palmar and then in the dorsal direction. The total translation of the ulna was calculated as the sum of the mean dorsal and palmar translations.

RESULTS

The mean total ulnar translation before and after TFCC disruption, and after TFCC repair was 5.94 ± 2.16 mm, 9.08 ± 2.64 mm, and 6.04 ± 2.18 mm, respectively. The specimens demonstrated a significant increase in the total translation of the ulna after disruption of the ulnar attachment of TFCC (P = .003), whereas a significant decrease was observed after TFCC foveal repair (P = .003). The median percentage of eliminated translation after TFCC repair was 64% and 172%, respectively, in groups I and II (P = .043).

CONCLUSIONS

The athroscopic transosseous suture technique demonstrated superior repair efficacy to the open repair technique in terms of biomechanical strength. This cadaveric study also demonstrated the feasibility of a new aiming device.

CLINICAL RELEVANCE

When making decisions about TFCC foveal repair, arthroscopic transosseous suture technique may provide better biomechanical strength than the open repair technique.