Functional kinematics of the wrist

How Multifunctioning Joints Produce Highly Agile Limbs in Animals with Lessons for Robotics

This paper reviews how multifunctioning joints produce highly agile limbs in animals with lessons for robotics. One of the key reasons why animals are so fast and agile is that they have multifunctioning joints in their limbs. The multifunctioning joints lead to a high degree of compactness which then leads to a host of benefits such as low mass, low moment of inertia and low drag. This paper presents three case studies of multifunctioning joints-the human wrist joint, knee joint and foot joints-in order to identify how multifunctioning is achieved and what lessons can be learned for robotics. It also reviews the multifunctioning nature of muscle which plays an important role in joint actuation. A key finding is that multifunctioning is achieved through various means: multiple degrees of freedom, multifunctioning parts, over-actuation and reconfiguration. In addition, multifunctioning is achieved through highly sophisticated layouts with high levels of integration and fine-tuning. Muscle also makes an important contribution to animal agility by performing multiple functions including providing shape, protection and heat. The paper reviews progress in achieving multifunctioning in robot joints particularly for the wrist, knee and foot. Whilst there has been some progress in creating multifunctioning robotic joints, there is still a large gap between the performance of animal and robotic joints. There is an opportunity to improve the agility of robots by using multifunctioning to reduce the size and mass of robotic joints.

Proximal row carpectomy or scaphoid excision and four-corner arthrodesis for treatment of scapholunate advanced collapse arthritis

Degenerative wrist conditions, such as scapholunate advanced collapse and scaphoid nonunion advanced collapse, often require salvage procedures to reduce pain and improve function. For early stages of disease, both proximal row carpectomy and scaphoid excision four-corner arthrodesis are viable motion-preserving options. There remains controversy on which technique is superior. Selection is a nuanced decision that requires consideration of patient characteristics and stage of disease. The traditional notion that proximal row carpectomy should be reserved for older individuals with low demands has been challenged; long-term studies in younger populations demonstrate similar patient-reported outcomes, pain relief and survivorship without conversion to total wrist arthrodesis between proximal row carpectomy and four-corner arthrodesis. The existing evidence suggests proximal row carpectomy has advantages of greater range of motion, fewer complications and lower costs. Advancements such as arthroscopic techniques for both procedures show potential, although mastery involves a steep learning curve.

Automatic analysis of the scapholunate distance using 4DCT imaging: normal values in the healthy wrist

AIM

Early diagnosis of scapholunate ligament (SLL) injuries is crucial to prevent progression to debilitating osteoarthritis. Four-Dimensional Computed Tomography (4DCT) is a promising dynamic imaging modality for assessing such injuries. Capitalizing on the known correlation between SLL injuries and an increased scapholunate distance (SLD), this study aims to develop a fully automatic approach to evaluate the SLD continuously during wrist motion and to apply it to a dataset of healthy wrists to establish reference values.

MATERIALS AND METHODS

50 healthy wrists were analysed in this study. All subjects performed radioulnar deviation (RUD), flexion-extension (FE), and clenching fist (CF) movements during 4DCT acquisition. A novel, automatic method was developed to continuously compute the SLD at five distinct locations within the scapholunate joint, encompassing a centre, volar, dorsal, proximal, and distal measurement.

RESULTS

The developed algorithm successfully processed datasets from all subjects. Our results showed that the SLD remained below 2 mm and exhibited minimal changes (median ranges between 0.3 mm and 0.65 mm) during RUD and CF at all measured locations. During FE, the volar and dorsal SLD changed significantly, with median ranges of 0.90 and 1.27 mm, respectively.

CONCLUSION

This study establishes a unique database of normal SLD values in healthy wrists during wrist motion. Our results indicate that, aside from RUD and CF, FE may also be important in assessing wrist kinematics. Given the labour-intensive and time-consuming nature of manual analysis of 4DCT images, the introduction of this automated algorithm enhances the clinical utility of 4DCT in diagnosing dynamic wrist injuries.

Detection of scapholunate interosseous ligament injury using dynamic computed tomography-derived arthrokinematics: A prospective clinical trial

Scapholunate interosseous ligament injuries are a major cause of wrist instability and can be difficult to diagnose radiographically. To improve early diagnosis of scapholunate ligament injuries, we compared injury detection between bilateral routine clinical radiographs, static CT, and dynamic four-dimensional CT (4DCT) during wrist flexion-extension and radioulnar deviation. Participants with unilateral scapholunate ligament injuries were recruited to a prospective clinical trial investigating the diagnostic utility of 4DCT imaging for ligamentous wrist injury. Twenty-one participants underwent arthroscopic surgery to confirm scapholunate ligament injury. Arthrokinematics, defined as distributions of interosseous proximities across radioscaphoid and scapholunate articular surfaces at different positions within the motion cycle, were used as CT-derived biomarkers. Preoperative radiographs, static CT, and extrema of 4DCT were compared between uninjured and injured wrists using Wilcoxon signed rank or Kolmogorov-Smirnov tests. Median interosseous proximities at the scapholunate interval were significantly greater in the injured versus the uninjured wrists at static-neutral and maximum flexion, extension, radial deviation, and ulnar deviation. Mean cumulative distribution functions at the radioscaphoid joint were not significantly different between wrists but were significantly shifted at the scapholunate interval towards increased interosseous proximities in injured versus uninjured wrists in all positions. Median and cumulative distribution scapholunate proximities from static-neutral and 4DCT-derived extrema reflect injury status.

Real-time MRI of the moving wrist at 0.55 tesla

OBJECTIVES

Magnetic resonance imaging (MRI) using 1.5T or 3.0T systems is routinely employed for assessing wrist pathology; however, due to off-resonance artifacts and high power deposition, these high-field systems have drawbacks for real-time (RT) imaging of the moving wrist. Recently, high-performance 0.55T MRI systems have become available. In this proof-of-concept study, we tested the hypothesis that RT-MRI during continuous, active, and uninterrupted wrist motion is feasible with a high-performance 0.55T system at temporal resolutions below 100 ms and that the resulting images provide visualization of tissues commonly interrogated for assessing dynamic wrist instability.

METHODS

Participants were scanned during uninterrupted wrist radial-ulnar deviation and clenched fist maneuvers. Resulting images (nominal temporal resolution of 12.7-164.6 ms per image) were assessed for image quality. Feasibility of static MRI to supplement RT-MRI acquisition was also tested.

RESULTS

The RT images with temporal resolutions < 100 ms demonstrated low distortion and image artifacts, and higher reader assessment scores. Static MRI scans showed the ability to assess anatomical structures of interest in the wrist.

CONCLUSION

RT-MRI of the wrist at a high temporal resolution, coupled with static MRI, is feasible with a high-performance 0.55T system, and may enable improved assessment of wrist dynamic dysfunction and instability.

ADVANCES IN KNOWLEDGE

Real-time MRI of the moving wrist is feasible with high-performance 0.55T and may improve the evaluation of dynamic dysfunction of the wrist.

Clinical measurement of functional dart thrower's motion in patients with unilateral wrist conditions undergoing nonoperative or postoperative hand therapy

STUDY DESIGN

Cross-sectional and descriptive study BACKGROUND: Functional dart thrower's motion (F-DTM) is an obliquely oriented wrist motion that occurs in activities such as throwing and drinking from a cup. There is limited data on clinical measurement of F-DTM.

PURPOSE OF THE STUDY

The purpose of this study was to 1) describe and establish reference scores for F-DTM measurement for nonoperative and postoperative wrist patients 2) compare F-DTM between the affected and nonaffected sides and 3) determine F-DTM score agreement across three consecutive trials.

METHODS

Two certified hand therapists evaluated F-DTM in consecutive adult patients with a unilateral wrist condition undergoing nonoperative or postoperative therapy. Three trials of goniometer measurements for radial extension (RE) and ulnar flexion (UF) were assessed on the nonaffected and affected wrists. A total arc F-DTM was computed. Mean, 95% confidence intervals (CI), and Cohen's d effect size described side-to-side differences in RE, UF, and total arc F-DTM. Agreement in scores across trials was assessed with an intraclass correlation coefficient (ICC).

RESULTS

Thirty-one nonoperative (mean ± SD age = 40.0 ± 13.9 years, 74% female, 94% right hand dominant) and 44 postoperative patients (mean ± SD age = 44.9 ± 14.9 years, 66% female, 84% right hand dominant) were enrolled. The average side-to-side difference, in degrees, in the nonoperative group was -6.4 (95% CI: -9.4 to -3.4, Cohen's d = 0.8) for RE, -10.4 (-16.7 to -4.0, d = 0.6) for UF, and -16.8 (-24.3 to -9.2, d = 0.8) for total arc F-DTM. The average side-to-side difference in the postoperative group was -33.6 (-38.8 to -28.3, d = 1.9) for RE, -34.7 (-40.6 to -28.7, d = 1.8) for UF, and -68.2 (-77.9 to -58.5, d = 2.1) for total arc F-DTM. The range of ICCs for F-DTM measurements was 0.82-0.96.

CONCLUSIONS

Goniometer measurement of F-DTM is a clinically feasible method to quantify functional motion loss in an injured wrist population, particularly patients with postoperatively managed wrist conditions.

A Kinematic Analysis of Wrist and Carpal Function Using Four-Dimensional Computed Tomography Technology: A Dynamic Perspective

PURPOSE

An emerging imaging modality, four-dimensional computed tomography, can provide dynamic evaluation of carpal motion, which allows for a better understanding of how the carpals work together to achieve range of motion. The objective of this work was to examine kinematic motion of the carpus through a flexion/extension arc of motion using four-dimensional computed tomography.

METHODS

A convenience sample of 20 uninjured participants underwent a four-dimensional computed tomography scanning protocol through a complete arc of flexion/extension motion. Kinematic changes in motion were quantified using helical axes motion data for each carpal. Rotation angles were compared between bones to identify differences in kinematic motion between bones.

RESULTS

The bones within the proximal carpal row, the lunate, scaphoid, and triquetrum, rotate significantly to differing magnitudes at the ends of motion (40° of flexion and 40° of extension). The scaphoid rotates to the highest magnitude, followed by the triquetrum, and lastly, the lunate. The distal carpal row bones rotate to similar magnitudes throughout the entire range of motion.

CONCLUSIONS

This work describes the kinematics of the carpals throughout dynamic in vivo flexion and extension.

CLINICAL RELEVANCE

This study adds to an understanding of wrist mechanics and the possible clinical implications of pathological deviation from baseline kinematics.

Development and Validation of a Survey to Measure Patients' Expectations of Wrist Arthritis Surgery

Background  The purpose of this study was to develop and test a patient-derived expectations survey for wrist arthritis surgery. We hypothesized that preoperative patient expectations are higher in people with greater functional impairment and that postoperative fulfilment of patient expectations correlates with functional improvement. Methods  The study was conducted in four phases. Development (n = 22) Preoperatively, patients were asked open-ended questions regarding expectations of surgery. A draft survey was then assembled. Reliability (n = 35) The survey was administered twice preoperatively. Concordance was measured with weighted kappa values and intraclass correlations (ICC). Validity (n = 58) Validity was assessed by comparing responses from the Expectations Survey to the patient-rated wrist evaluation (PRWE). Responsiveness (n = 18) Responsiveness was calculated by comparing the proportion of expectations fulfilled to PRWE scores 1-year postoperatively. Results   Development Twenty-two distinct items representing the most frequent responses were utilized from the draft survey items of 1,244 expectations volunteered. Reliability Patients had high preoperative expectations of surgery (mean = 76.8); 30% had scores ≥90. Test-retest reliability was high (Cronbach α coefficients = 0.91, 0.93, ICC = 0.86). Endorsement of items = 66 to 100%; and weighted kappa values = 0.39 to 0.96. Validity Patients with greater preoperative expectations (≥63) had more pain, worse function, and worse PRWE scores than those with lower expectations. Responsiveness The proportion of fulfilled expectations was high (mean 0.80, median 0.79), and greater fulfillment (proportion > 0.80, n  = 8) was associated with better postoperative PRWE scores. Conclusion  The patient-derived expectations survey is reliable, valid, responsive, and addresses a spectrum of expectations for patients undergoing surgery for wrist arthritis. Clinical relevance Understanding patient expectations can contribute to customized care given the range of surgical choices for the arthritic wrist.

Management of giant cell tumors of the distal radius

Background

The distal radius is the most common location for giant cell tumors (GCT) in the upper extremity. Treatment should balance the goals of maximizing function and minimizing recurrence and other complications. Given the complexity in surgical treatment, various techniques have been described without clear standards of treatment.

Objectives

The purpose of this review is to provide an overview of evaluation of patients presenting with GCT of the distal radius, discuss management, and provide an updated summary on outcomes of treatment options.

Conclusion

Surgical treatment should consider tumor Grade, involvement of the articular surface, and patient-specific factors. Options include intralesional curettage and en bloc resection with reconstruction. Within reconstruction techniques, radiocarpal joint preserving and sparing procedures can be considered. Campanacci Grade 1 tumors can be successfully treated with joint preserving procedures, whereas for Campanacci Grade 3 tumors consideration should be given to joint resection to prevent recurrence. Treatment of Campanacci Grade 2 tumors is debated in the literature. Intralesional curettage and adjuvants can successfully treat cases where the articular surface can be preserved, while en-bloc resection should be used in cases where the articular surface cannot undergo aggressive curettage. A variety of reconstructive techniques are used for cases needing resection, with no clear gold standard. Joint sparing procedures preserve motion at the wrist joint, whereas joint sacrificing procedures preserve grip strength. Choice of reconstructive procedure should be made based on patient-specific factors, considering relative functional outcomes, complications, and recurrence rates.

Movement preferences of the wrist and forearm during activities of daily living

BACKGROUND

During activities of daily living, the main degrees of freedom of the forearm and wrist-forearm pronation-supination (PS), wrist flexion-extension (FE), and wrist radial-ulnar deviation (RUD)-combine seamlessly to allow the hand to engage with and manipulate objects in our environment. Yet the combined behavior of these three degrees of freedom is relatively unknown.

PURPOSE

To provide a characterization of natural forearm and wrist kinematics (joint configuration, movement direction, and speed) during activities of daily living.

STUDY DESIGN

This is a descriptive cross-sectional study.

METHODS

Ten healthy subjects performed 24 activities of daily living chosen to represent a wide variety of activities, while we measured their PS, FE, and RUD angles using electromagnetic motion capture. The orientation of the forearm and wrist was represented in the three-dimensional "configuration space" spanned by PS, FE, and RUD. From the time course of forearm and wrist orientation in configuration space, we extracted three-dimensional distributions of joint configuration, movement direction, and speed.

RESULTS

Most joint configurations were focused in a relatively small area: subjects spent roughly 50% of the time in the central 20% of their functional range of motion. Some movement directions were significantly more common than others (p < 0.001); in particular, the direction of the dart-thrower's motion (DTM) was about three times more common than motion perpendicular to it. Most movements were slow: the likelihood of moving at increasing speeds dropped off exponentially. Interestingly, the most common high-speed motion combined the DTM with a twist from pronation to supination. As this motion allows one to pick up an object in front of one's body and bring it to the head, it is essential for self-care. Thus, although many activities of daily living follow the DTM without significant forearm rotation, the greatest importance of the DTM may lie in its combination with forearm rotation.

CONCLUSIONS

Despite the wide variety of activities, we found evidence of preferred movement behavior, and this behavior showed significant coupling between the wrist and forearm.

Assessing carpal kinematics following scapholunate interosseous ligament injury ex vivo using four-dimensional dynamic computed tomography

BACKGROUND

Scapholunate interosseous ligament injuries are prevalent and often challenging to diagnose radiographically. Four-dimensional CT allows visualization of carpal bones during motion. We present a cadaveric model of sequential ligamentous sectionings ("injuries") to quantify their effects on interosseous proximities at the radioscaphoid joint and scapholunate interval. We hypothesized that injury, wrist position, and their interaction affect carpal arthrokinematics.

METHODS

Eight cadaveric wrists were moved through flexion-extension and radioulnar deviation after injuries. Dynamic CT images of each motion were acquired in each injury condition using a second-generation dual-source CT scanner. Carpal osteokinematics were used to calculate arthrokinematic interosseous proximity distributions during motion. Median interosseous proximities were normalized and categorized by wrist position. Linear mixed-effects models and marginal means tests were used to compare distributions of median interosseous proximities.

FINDINGS

The effect of wrist position was significant for both flexion-extension and radioulnar deviation at the radioscaphoid joint; the effect of injury was significant for flexion-extension at the scapholunate interval; and the effect of their interaction was significant for radioulnar deviation at the scapholunate interval. Across wrist positions, radioscaphoid median interosseous proximities were less able to distinguish injury conditions versus scapholunate proximities. Median interosseous proximities at the scapholunate interval are majoritively able to detect differences between less (Geissler I-III) versus more (Geissler IV) severe injuries when the wrist is flexed, extended, and ulnarly-deviated.

INTERPRETATION

Dynamic CT enhances our understanding of carpal arthrokinematics in a cadaveric model of SLIL injury. Scapholunate median interosseous proximities in flexion, extension, and ulnar deviation best demonstrate ligamentous integrity.

Evaluation of Scapholunate Injury and Repair with Dynamic (4D) CT: A Preliminary Report of Two Cases

Background  In predynamic or dynamic scapholunate (SL) instability, standard diagnostic imaging may not identify SL interosseous ligament (SLIL) injury, leading to delayed detection and intervention. This study describes the use of four-dimensional computed tomography (4DCT) in identifying early SLIL injury and following injured wrists to 1-year postoperatively. Description of Technique  4DCT acquires a series of three-dimensional volume data with high temporal resolution (66 ms). 4DCT-derived arthrokinematic data can be used as biomarkers of ligament integrity. Patients and Methods  This study presents the use of 4DCT in a two-participant case series to assess changes in arthrokinematics following unilateral SLIL injury preoperatively and 1-year postoperatively. Patients were treated with volar ligament repair with volar capsulodesis and arthroscopic dorsal capsulodesis. Arthrokinematics were compared between uninjured, preoperative injured, and postoperative injured (repaired) wrists. Results  4DCT detected changes in interosseous distances during flexion-extension and radioulnar deviation. Generally, radioscaphoid joint distances were greatest in the uninjured wrist during flexion-extension and radioulnar deviation, and SL interval distances were smallest in the uninjured wrist during flexion-extension and radioulnar deviation. Conclusion  4DCT provides insight into carpal arthrokinematics during motion. Distances between the radioscaphoid joint and SL interval can be displayed as proximity maps or as simplified descriptive statistics to facilitate comparisons between wrists and time points. These data offer insight into areas of concern for decreased interosseous distance and increased intercarpal diastasis. This method may allow surgeons to assess whether (1) injury can be visualized during motion, (2) surgery repaired the injury, and (3) surgery restored normal carpal motion. Level of Evidence  Level IV, Case series.

Proximal row carpectomy versus four-corner arthrodesis in the treatment of SLAC and SNAC wrist: meta-analysis and literature review

A systematic literature review was performed on 84 articles from 2000 to 2020 on proximal row carpectomy (PRC) or four-corner arthrodesis (FCA) in patients with posttraumatic wrist osteoarthritis. Qualitative assessment was conducted on 14 articles. Pain, range of motion (ROM), grip strength and complications were analyzed using weighted average means. Meta-analysis with a random effects model was performed for the flexion-extension arc and grip strength. A total of 1,066 PRCs and 2,771 FCAs were analyzed, with a mean follow-up of 9 and 7 years respectively. Mean flexion after PRC and FCA respectively was 36.2 ° and 31.1 °, mean extension 41.4 ° and 32.4 °, and mean grip strength 26.4 kg and 27.5 kg. PRC had a larger flexion-extension arc than FCA, with a standard mean difference (SMD) of 0.41 (range, 0.02-0.81). No significant difference was found for grip strength. Osteoarthritis occurred in 42.2% of PRC cases, independently of capitate shape. Conversion to wrist arthrodesis was performed in 10.1% of failed PRCs. Revision was chosen in 4.7% of FCAs and conversion to wrist arthrodesis in 4.6%. We conclude that the functional results of both techniques are similar, but prefer PRC to FCA because of the lower complications rate.

Augmented reality-based surgical guidance for wrist arthroscopy with bone-shift compensation

BACKGROUND AND OBJECTIVES

Intraoperative joint condition is different from preoperative CT/MR due to the motion applied during surgery, inducing an inaccurate approach to surgical targets. This study aims to provide real-time augmented reality (AR)-based surgical guidance for wrist arthroscopy based on a bone-shift model through an in vivo computed tomography (CT) study.

METHODS

To accurately visualize concealed wrist bones on the intra-articular arthroscopic image, we propose a surgical guidance system with a novel bone-shift compensation method using noninvasive fiducial markers. First, to measure the effect of traction during surgery, two noninvasive fiducial markers were attached before surgery. In addition, two virtual link models connecting the wrist bones were implemented. When wrist traction occurs during the operation, the movement of the fiducial marker is measured, and bone-shift compensation is applied to move the virtual links in the direction of the traction. The proposed bone-shift compensation method was verified with the in vivo CT data of 10 participants. Finally, to introduce AR, camera calibration for the arthroscope parameters was performed, and a patient-specific template was used for registration between the patient and the wrist bone model. As a result, a virtual bone model with three-dimensional information could be accurately projected on a two-dimensional arthroscopic image plane.

RESULTS

The proposed method was possible to estimate the position of wrist bone in the traction state with an accuracy of 1.4 mm margin. After bone-shift compensation was applied, the target point error was reduced by 33.6% in lunate, 63.3% in capitate, 55.0% in scaphoid, and 74.8% in trapezoid than those in preoperative wrist CT. In addition, a phantom experiment was introduced simulating the real surgical environment. AR display allowed to expand the field of view (FOV) of the arthroscope and helped in visualizing the anatomical structures around the bones.

CONCLUSIONS

This study demonstrated the successful handling of AR error caused by wrist traction using the proposed method. In addition, the method allowed accurate AR visualization of the concealed bones and expansion of the limited FOV of the arthroscope. The proposed bone-shift compensation can also be applied to other joints, such as the knees or shoulders, by representing their bone movements using corresponding virtual links. In addition, the movement of the joint skin during surgery can be measured using noninvasive fiducial markers in the same manner as that used for the wrist joint.

Proximal row carpectomy generates better mid- to long-term outcomes than four-corner arthrodesis for post-traumatic wrist arthritis: A meta-analysis

INTRODUCTION

In posttraumatic wrist arthritis of intermediate severity, two main palliative procedures are used to preserve some mobility in the wrist: proximal row carpectomy (PRC) and scaphoid excision followed by four corner arthrodesis (4CA). Despite satisfactory overall results, the debate continues about which one provides the best results and long-term outcomes, particularly prevention of arthritis progression. Recent comparative studies now provide us with information about mid- and long-term results. The aim of this study was to compare the clinical results, complications, conversion rate to total wrist arthrodesis and progression to osteoarthritis of PRC versus 4CA in the medium and long term.

HYPOTHESIS

The null hypothesis was that there is no significant difference between PRC and 4CA in the clinical results, complications, conversion to total wrist arthrodesis and arthritis progression.

MATERIALS AND METHODS

A systematic literature review was carried out by following the PRISMA guidelines. Included were studies comparing 4CA and PRC for the treatment of post-traumatic wrist arthritis secondary to scapholunate dissociation (SLAC) and scaphoid nonunion (SNAC) with a mean follow-up of 5 years. A search was performed of the MEDLINE, EMBASE and Cochrane databases that identified 831 articles. After removing 230 duplicates and excluding 595 articles based on their title and/or abstract, and then adding 1 article manually, 7 articles were included in our analysis. Parameters analyzed were range of motion (ROM), pain, grip strength, functional scores, complications, conversion to total wrist arthrodesis, and arthritis progression.

RESULTS

In the 7 articles, 1059 wrists - 582 PRC and 477 4CA - were analyzed with follow-up ranging from 5.2 to 18 years. PRC produced significantly better ROM in flexion (weighted mean difference [WMD]=10.0°; p<0.01) and in ulnar deviation (WMD=8.7°; p<0.01) along with significantly lower complication rates (OR=0.3; p<0.01) and reoperation rates (OR=0.1; p<0.01). There was no significant difference in the conversion rate, grip strength, extension, radial deviation, pain, DASH and PRWE scores. The progression of osteoarthritis could not be analyzed due to lack of data.

DISCUSSION

This meta-analysis was the first to include recently published mid- and long-term studies comparing PRC and 4CA. The main finding is that PRC is superior overall with better ROM and a lower complication rate. Another important finding was the absence of differences in grip strength and the conversion rate to total wrist arthrodesis. Unfortunately, the lack of systematic studies on arthritis progression leaves this question unanswered. Our findings must be interpreted cautiously because it was impossible to stratify the cases by etiology and osteoarthritis stage.

LEVEL OF EVIDENCE

III; systematic review and meta-analysis.

Predictors of Failure for Vascularized and Nonvascularized Bone Grafting of Scaphoid Nonunions: A Systematic Review

Objective  This article compares predictors of failure for vascularized (VBG) and nonvascularized bone grafting (NVBG) of scaphoid nonunions. Methods  We conducted a systematic literature review of outcomes after VBG and NVBG of scaphoid nonunion. Fifty-one VBG studies ( N  = 1,419 patients) and 81 NVBG studies ( N  = 3,019 patients) met the inclusion criteria. Data were collected on surgical technique, type of fixation, time from injury to surgery, fracture location, abnormal carpal posture (humpback deformity and/or dorsal intercalated segmental instability [DISI]), radiographic parameters of carpal alignment, prior failed surgery, smoking status, and avascular necrosis (AVN) as defined by punctate bleeding, magnetic resonance imaging (MRI) with contrast, MRI without contrast, X-ray, and histology. Meta-analysis of proportions was conducted with Freeman-Tukey double arcsine transformation. Multilevel mixed-effects analyses were performed with univariable and multivariable Poisson regression to identify confounders and evaluate predictors of failure. Results  The pooled failure incidence effect size was comparable between VBG and NVBG (0.09 [95% confidence interval [CI] 0.05-0.13] and 0.08 [95% CI 0.06-0.11], respectively). Humpback deformity and/or DISI (incidence-rate radios [IRRs] 1.57, CI: 1.04-2.36) and lateral intrascaphoid angle (IRR 1.21, CI: 1.08-1.37) were significantly associated with an increased VBG failure incidence. Time from injury to surgery (IRR 1.09, CI: 1.06-1.12) and height-to-length (H/L) ratio (IRR 53.98, CI: 1.16-2,504.24) were significantly associated with an increased NVBG failure incidence, though H/L ratio demonstrated a wide CI. Decreased proximal fragment contrast uptake on MRI was a statistically significant predictor of increased failure incidence for both VBG (IRR 2.03 CI: 1.13-3.66) and NVBG (IRR 1.39, CI: 1.16-1.66). Punctate bleeding or radiographic AVN, scapholunate angle, radiolunate angle, and prior failed surgery were not associated with failure incidence for either bone graft type ( p > 0.05). Conclusion  Humpback deformity and/or DISI and increasing lateral intrascaphoid angle may be predictors of VBG failure. Time from injury to surgery may be a predictor of NVBG failure. AVN as defined by decreased contrast uptake on MRI may be a marker of increased failure risk for both bone graft types.

The impact of Chikungunya chronic arthralgia on women’s upper limbs motor function: a cross-sectional study

ABSTRACT Post-Chikungunya chronic arthralgia (PCCA) may lead to musculoskeletal repercussions and functional loss. The objective was to assess the upper limb physical disability and symptoms during daily, work, and leisure activities of women presenting PCCA compared to healthy controls (HC). This was a cross-sectional study conducted with 52 women. The participants were divided into PCCA (37) and HC (15) groups. Handgrip strength, range of motion, level of pain (numerical rating scale), and participants’ physical disability and symptoms (Disabilities of the Arm, Shoulder, and Hand Questionnaire - DASH) were evaluated. Differences between groups were evaluated using the Students t-test and Pearson’s correlations. The chi-square test was applied for categorical variables. The significance was set at α=0.05. The disease duration was 19.5±13.1 months. We found no differences between groups for peak force (PCAA:23.6±7.4kgf; HC: 24.5±6.2kgf; p=0.676). The results showed a significant difference between groups regarding range of motion (PCCA: 63.5±17.3o; HC: 77.2±9.6o), level of hand pain (PCCA: 5.8±2.2; HC: 0.4±1.5), and upper limbs functional levels (PCCA: 44.5±17.4; HC: 16.2±20.5). Participants related severe difficulty or inability to perform tasks such as opening a jar (78.4%), placing objects above head height (48.7%), doing heavy household chores (56.8%), and gardening (51.4%). Impairment in the upper limb physical function in daily, work, and leisure activities shows the higher prevalence in the long-term.

Perilunate Dislocations: Current Treatment Options

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Approximately 25% of all patients who sustain perilunate dislocations present in a delayed fashion.

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While management of acute injuries is relatively well-described, treatment of chronic injuries can be complex and there is a paucity of scientific evidence to guide management.

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Treatment options include open reduction internal fixation, proximal row carpectomy, scaphoid or lunate excision with or without arthrodesis, and total wrist arthrodesis, although indications vary based on chronicity of injury and patient factors.

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The purpose of this article was to determine the quality of evidence supporting surgical options for the treatment of these injuries.

Radiocarpal Fusion: Indications, Technique, and Modifications

Degenerative disorders of the wrist may affect isolated joints and inhibit normal functions of the wrist secondary to pain and stiffness. These processes that affect only the radiocarpal joint may be secondary to posttraumatic osteoarthritis, primary osteoarthritis, or rheumatoid arthritis. Radiocarpal wrist arthrodesis may help preserve some of the native wrist kinematics while alleviating pain and improving the range of motion. However, the surgeon must ensure that the patient's pathologic process primarily affects the radiocarpal articulations while relatively sparing the midcarpal articulations. Depending on the location of the pathology, isolated radiolunate or radioscapholunate arthrodesis have been described to preserve some motion in the midcarpal joint. To maximize motion in the midcarpal joint after radiocarpal arthrodesis, techniques for distal scaphoid and triquetrum excision have been described. We report patient outcomes for various techniques and describe our preferred technique for radioscapholunate arthrodesis using distal scaphoid excision.

Anatomy, Biomechanics, and Loads of the Wrist Joint

The wrist is by far the most differentiated section of the musculoskeletal system. The spectrum of wrist injuries ranges from minor injuries to complex traumas with simultaneous loss of functions, resulting in enormous economic costs. A proper understanding of the anatomy and biomechanics is essential for effective treatment, whether conservative or surgical; this applies to the wrist no less than to other parts of the human body. Here; information on the wrist anatomy; kinematics; and biomechanical behavior is presented, commencing with a brief explanation of the structure of its hard and soft tissues. Eight carpal bones in combination with two forearm bones (radius and ulna) construct the wrist joint. The motion of the wrist joint is initiated by the muscles of the forearm, and strong and short ligaments ensure the stability of the wrist. All of these components are essential to bringing functions to the wrist joint because these structures allow wrist mobility and sustainability. In addition, the kinematics of the wrist joint is presented and different biomechanical model approaches. The therapeutic (surgical) restoration of the balance between the load–bearing capacity and the actual stress on a joint is the prerequisite for a lifelong and trouble-free function of a joint. Regarding the complex clinical problems, however, a valid biomechanical wrist joint model would be necessary as assistance, to improve the success of systematized therapies based on computer–aided model–based planning and intervention.

The Utility of Quantitative CT (QCT) to Detect Differences in Subchondral Bone Mineral Density Between Healthy People and People with Pain Following Wrist Trauma

The mechanisms underlying chronic pain development following musculoskeletal trauma are complex and multifactorial. In their search, some researchers are turning to the subchondral bone as a potential contributor to pain due to its vascularity, using a depth-specific imaging technique. However, this technique has been mainly used in the knee. We propose the use of a quantitative computed tomography (QCT) depth-specific analysis to measure subchondral bone following wrist trauma. Ten participants (n=5 post-trauma; n=5 healthy) underwent bilateral CT scans of their wrist accompanied by a calibration phantom with known densities. Average subchondral vBMD was studied at three depths from the subchondral surface (0 to 2.5, 2.5 to 5, 5 to 7.5mm) according to radial articular surface contact in both wrists of each participant. Percentage differences and Cohen's d effect sizes were calculated to analyze bilateral vBMD and vBMD differences between groups. This image-based tool demonstrated subject-specific, depth-specific, and joint-specific measures of vBMD within the wrist. This methodology highlighted the differences between depth-specific vBMD in healthy people and people who have experienced wrist trauma. Overall, the healthy cohort demonstrated higher vBMD across all three depths and both articular surfaces. This imaging technique further distinguished between subchondral cortical and trabecular bone, wherein clinical implications can be drawn from these distinctions in future work. Our study therefore supports the utility of a QCT imaging technique in detecting differences in depth-specific vBMD in the wrist.

Clinical evaluation of a wrist sensorimotor rehabilitation program for triangular fibrocartilage complex injuries

Introduction

Triangular fibrocartilage complex (TFCC) injuries are associated with distal radioulnar joint (DRUJ) instability and impaired wrist proprioception. Sensorimotor training of extensor carpi ulnaris (ECU) and pronator quadratus (PQ) can enhance DRUJ stability. With limited evidence on effectiveness of TFCC sensorimotor rehabilitation, this study aimed to evaluate the effects and feasibility of a novel wrist sensorimotor rehabilitation program (WSRP) for TFCC injuries.

Methods

Patients diagnosed with TFCC injuries were recruited from May 2018 to January 2020 at an outpatient hand clinic in Singapore General Hospital. There are four stages in WSRP: (1) pain control, (2) muscle re-education and joint awareness, (3) neuromuscular rehabilitation, and (4) movement normalization and function. WSRP also incorporated dart throwing motion and proprioceptive neuromuscular facilitation. Outcome measures included grip strength measured with grip dynamometer, numerical pain rating scale, joint position sense (JPS) measurement, weight bearing measured with the 'push-off' test, and wrist function reported on the Patient Rated Wrist Hand Evaluation.

Results

Ten patients completed the WSRP. Mean changes were compared with minimal clinically important differences (MCID) for outcomes. All patients achieved MCID on pain, 70% of patients achieved MCID on grip strength, weight bearing and wrist function. Paired t-tests and Cohen's D for outcome measures were calculated. There were large effect sizes of 2.47, 1.35, and 2.81 for function, grip strength and pain respectively, and moderate effect sizes of 0.72 and 0.39 for axial loading and JPS respectively.

Discussion

WSRP presents a potential treatment approach in TFCC rehabilitation. There is a need for future prospective clinical trials with control groups.

Four-dimensional CT analysis of carpal kinematics: An explorative study on the effect of sex and hand-dominance

Wrist pathology is often diagnosed by using the contralateral wrist as a comparison of baseline motion and strength. However, recent range of motion studies suggest that females have different carpal motion patterns compared to males and that the dominant carpal bones have different motion patterns. The purpose of this study is to evaluate the effect of sex and hand dominance on in vivo kinematics of the scaphoid, lunate and capitate using four-dimensional computed tomography (4D-CT) analysis in healthy uninjured volunteers. In this prospective study, both wrist of 20 uninjured Caucasian volunteers (11 men and 9 women) were assessed using 4D-CT during active flexion-extension and radial-ulnar deviation. A linear mixed model was used to compare the carpal motion patterns. Sex had no influence on carpal kinematics. Hand-dominance in males did have a significant effect on carpal kinematics. During flexion-extension of the male wrist, more radial-ulnar deviation of the lunate, scaphoid and capitate of the non-dominant hand was seen. During radial-ulnar deviation of the male wrist, radial-ulnar deviation and pro-supination of the lunate was more in the dominant hand. This study provides a better understanding of carpal kinematics and the effect of sex and hand-dominance on the scaphoid, lunate and capitate in uninjured wrists.

Self-identified functional limitations improve in patients with degenerative wrist arthritis after surgery

STUDY DESIGN

This is a prospective cohort pilot study.

BACKGROUND

Degenerative wrist arthritis leads to pain, loss of strength, mobility, function, and impairments in psychological well-being. Accurate assessment of functional limitations that are unique to the individual is essential for successful treatment that best meets those specific needs.

PURPOSE OF THE STUDY

To identify and determine if self-identified functional limitations improve in patients who underwent surgery for degenerative wrist arthritis.

METHODS

Patients with degenerative wrist arthritis who were scheduled for surgery were prospectively recruited (n = 14, mean age + SD = 42 + 16, 10 males, 4 females) into a pilot study that measured self-identified functional limitations and outcomes. Inclusion criteria included a diagnosis of scapholunate advanced collapse, scaphoid nonunion advanced collapse, scapholunate interosseous ligament tear, or Kienböck disease. Exclusion criteria included a history of neuromuscular disease or concomitant ipsilateral musculoskeletal injury. Data were collected during two 20-minute sessions, preoperatively and one year postoperatively, utilizing the Patient-Rated Wrist Evaluation and the Canadian Occupational Performance Measure.

RESULTS

All patients reported significant decreases (P < .001) in total pain (mean change = 17.6, SD = 8.5) and total disability (mean = 17.8, SD = 9.1) on the Patient-Rated Wrist Evaluation from presurgery to postsurgery, with a large effect size of d > 0.8. Patients also reported significant improvements (P < .001) in mean performance (mean = 3.5, SD = 1.5) and mean satisfaction (mean = 4.0, SD = 2.1) with self-identified activities on the Canadian Occupational Performance Measure, with an effect size of d > 0.8.

CONCLUSION

Patients with degenerative wrist arthritis reported significant postoperative improvement in both performance and satisfaction in self-identified activities. Consideration of patient-specified goals can inform both patients and clinicians during the surgical decision-making process and allow for more individualized care.

Correlation of hand functionality and grip strengths with anthropometric measurements

BACKGROUND

Using objective anthropometric measurement data and anthropometric ratios, grip strength and hand functionality can be evaluated.

OBJECTIVE

The aim of this study was to obtain anthropometric measurements regarding the forearm and hand, to evaluate the hand functionality in addition to hand and finger grip strengths, and to investigate the correlation between these values.

METHODS

One-hundred eight-four subjects between 18 and 25 years were included in the study. Forearm and hand anthropometric measurements and ratios were measured. Hand and lateral grip strengths were evaluated. Jebsen Taylor Hand Function Test (JTHFT) was used to assess hand functionality.

RESULTS

A statistically weak and consistently negative correlation between the ratios of forearm length to forearm/wrist circumferences and the ratio of hand length to metacarpal head circumference and hand-lateral grip strengths was found. There was a statistically weak and consistently negative correlation between these ratios and the subtests of JTHFT. It was shown that there was a statistically weak-moderate positive correlation between the hand-lateral grip strengths and JTHFT subtests.

CONCLUSIONS

In conclusion, when evaluating grip strength and hand functionality, forearm and hand anthropometric measurements and ratios, which could affect the results, should be considered.

Evaluation of Four-Dimensional Computed Tomography as a Technique for Quantifying Carpal Motion

Delayed diagnosis of dynamic carpal instability often occurs because early changes in bone alignment and movement are difficult to detect and manifest mainly during a dynamic/functional task. Current diagnostic tools are only able to examine the carpal bones under static or sequential-static conditions. Four-dimensional (three dimensions + time) computed tomography (4DCT) enables quantification of carpal mechanics through 3D volume sequences of the wrist in motion. A comprehensive understanding of carpal mechanics is needed to define normal function and structure and provide targets for treatment of carpal injuries. In this study, measurements of scaphoid translation and joint congruency were taken by creating models from the CT scans of the carpals in extreme frames of motion, registering those models to the neutral position, transforming the models into a local coordinate system, and using software to calculate the joint surface areas (JSA). Results indicated that the centroid of the scaphoid translated 6.4 ± 1.3 mm and extended from extreme radial to extreme ulnar deviation. Results are consistent with the literature. An additional study was performed to measure the responsiveness of the 4DCT technique presented. Bone models from each frame of motion for radio ulnar deviation (RUD) and flexion extension (FE) were created and distinct differences between their JSA were measured qualitatively and quantitatively. The results show that there was statistically significantly different JSA within carpal joints between RUD and FE. These studies provide the first step in developing the methodology when using 4DCT scanning to measure subtle abnormalities in the wrist.

In vivo articular contact pattern of a total wrist arthroplasty design

Total wrist arthroplasty (TWA) designs suffer from relatively high complication rates when compared to other arthroplasties. Understanding the contact pattern of hip and knee replacement has improved their design and function; however, the in vivo contact pattern of TWA has not yet been examined and is thus the aim of this study. We hypothesized that the center of contact (CoC) is located at the geometric centers of the carpal component and radial component in the neutral posture and that the CoC moves along the principal arcs of curvature throughout primary anatomical motions. Wrist motion and implant kinematics of six patients with the Freedom® total wrist implant were studied during various tasks using biplanar videoradiography. The location of the CoC of the components was investigated by calculating distance fields between the articular surfaces. We found the CoC at the neutral posture was not at the geometric centers but was located 3.5 mm radially on the carpal component and 1.2 mm ulnarly on the radial component. From extension to flexion, the CoC moved 10.8 mm from dorsal to volar side on the carpal component (p < 0.0001) and 7.2 mm from volar to dorsal on the radial component (p = 0.0009). From radial to ulnar deviation, the CoC moved 12.4 mm from radial to ulnar on the carpal component (p < 0.0001), and 5.6 mm from ulnar to radial on the radial component (p = 0.009). The findings of this study may eventually improve TWA success by advancing future designs through a more accurate understating of their kinematic performance in vivo.

Scapholunate ligament 360° procedure

AIMS

The purpose was to evaluate early clinical, patient-reported, and radiological outcomes of the scapholunate ligament 360° tenodesis (SL 360) technique for treatment of scapholunate (SL) instability.

METHODS

We studied the results of nine patients (eight males and one female with a mean age of 44.7 years (26 to 55)) who underwent the SL 360 procedure for reducible SL instability between January 2016 and June 2019, and who were identified from retrospective review of electronic medical records. Final follow-up of any kind was a mean of 33.7 months (12.0 to 51.3). Clinical, radiological, and patient-reported outcome data included visual analogue scale (VAS) for pain, Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH), Mayo Wrist Score (MWS), and Patient-Rated Wrist Examination (PRWE). Means were analyzed using paired t-test.

RESULTS

Before surgery, patients with SL instability were significantly impaired with respect to wrist flexion, extension, and grip strength (mean flexion, 51° (20° to 85°) vs 73° (45° to 90°); mean extension, 46° (15° to 70°) vs 66° (45° to 80°); mean grip strength, 25 kg (20 to 31) vs 50 kg (35 to 68) compared to the unaffected side). The mean SL gap (4.9 mm (2.3 to 7.3) vs 2.1 mm (1.6 to 2.9)) and mean SL angle (71° (59° to 105°) vs 50° (38° to 64°) were also significantly greater in the affected wrist. At final follow-up, there was mean improvement regarding clinical, radiological, and functional outcomes comparing preoperative to final postoperative values for the VAS for pain scale, QuickDASH, MWS, PRWE, and SL gap and SL angle.

CONCLUSION

In our small series, the SL 360 procedure for reducible SL instability has favourable early clinical, patient-reported, and radiological outcomes at a mean of 33.7 months (12.0 to 51.3). The suture tape and tendon construct confers robust stability, permitting earlier mobilization without the inherent disadvantages of Kirschner wire stabilization. Cite this article: Bone Joint J 2021;103-B(5):939-945.

The forearm and hand musculature of semi-terrestrial rhesus macaques (Macaca mulatta) and arboreal gibbons (fam.Hylobatidae). Part II. Quantitative analysis

Nonhuman primates have a highly diverse locomotor repertoire defined by an equally diverse hand use. Based on how primates use their hands during locomotion, we can distinguish between terrestrial and arboreal taxa. The 'arboreal' hand is likely adapted towards high wrist mobility and grasping, whereas the 'terrestrial' hand will show adaptations to loading. While the morphology of the forearm and hand bones have been studied extensively, functional adaptations in the forearm and hand musculature to locomotor behaviour have been documented only scarcely. In this paper, we investigate the forelimb musculature of the highly arboreal gibbons (including Hylobates lar,Hylobates pileatus,Nomascus leucogenys,Nomascus concolor and Symphalangus syndactylus) and compare this with the musculature of the semi-terrestrial rhesus macaques (Macaca mulatta). Anatomical data from previous dissections on knuckle-walking bonobos (Pan paniscus) and bipedal humans (Homo sapiens) are also included to further integrate the analyses in the scope of catarrhine hand adaptation. This study indicates that the overall configuration of the arm and hand musculature of these primates is very similar but there are some apparent differences in relative size which can be linked to differences in forelimb function and which might be related to their specific locomotor behaviour. In macaques, there is a large development of wrist deviators, wrist and digital flexors, and m. triceps brachii, as these muscles are important during the different phases of palmi- and digitigrade quadrupedal walking to stabilize the wrist and elbow. In addition, their m. flexor carpi ulnaris is the most important contributor to the total force-generating capacity of the wrist flexors and deviators, and is needed to counteract the adducting torque at the elbow joint during quadrupedal walking. Gibbons show a relatively high force-generating capacity in their forearm rotators, wrist and digital flexors, which are important muscles in brachiation to actively regulate forward movement of the body. The results also stress the importance of the digital flexors in bonobos, during climbing and clambering, and in humans, which is likely linked to our advanced manipulation skills.

Biomechanical function requirements of the wrist. Circumduction versus flexion/abduction range of motion

The biomechanical function of the wrist is widely assessed by measuring the range of motion (RoM) in two separate orthogonal planes: flexion-extension (FE) and radioulnar deviation (RUD). However, the two motions are coupled. The aim of this study is to compare wrist circumduction with FE and RUD RoM in terms of representativeness of the kinematic requirements for performing activities of daily living (ADL). To this end, the wrist motion of healthy participants was measured while performing maximum RoM in FE and in RUD, circumduction, and thirty-two representative ADL. Active and functional RoM (ARoM and FRoM) were computed in each plane, the evolving circumduction curves were adjusted to ellipses, and intensity maps representing the frequency of the coupling angles in ADL were plotted, both per ADL and globally for both hands. Ellipses representing different percentages of coupling angles in ADL were also plotted. Wrist circumduction fits the coupling angles measured in ADL better than ARoM or FRoM. As a novelty, quantitative data for both circumduction and the coupling angles required in ADL are provided, shedding light on the real biomechanical function requirements of the wrist. Results might be used to quantify mobility reduction and its impact on the performance of ADL, globally and per ADL, to enhance rehabilitation strategies, as well as in clinical decision-making, robotics, and prostheses.

Proximal-distal shift of the center of rotation in a total wrist arthroplasty is more than twice of the healthy wrist

Reproduction of healthy wrist biomechanics should minimize the abnormal joint forces that could potentially result in the failure of a total wrist arthroplasty (TWA). To date, the in vivo kinematics of TWA have not been measured and it is unknown if TWA preserves healthy wrist kinematics. Therefore, the purpose of this in vivo study was to determine the center of rotation (COR) for a current TWA design and to compare its location to the healthy wrist. The wrist COR for six patients with TWA and 10 healthy subjects were calculated using biplane videoradiography as the subjects performed various range-of-motion and functional tasks that included coupled wrist motions. An open-source registration software, Autoscoper, was used for model-based tracking and kinematics analysis. It was demonstrated that the COR was located near the centers of curvatures of the carpal component for the anatomical motions of flexion-extension and radial-ulnar deviation. When compared to healthy wrists, the COR of TWAs was located more distal in both pure radial deviation (P < .0001) and pure ulnar deviation (P = .07), while there was no difference in its location in pure flexion or extension (P = .99). Across all coupled motions, the TWA's COR shifted more than two times that of the healthy wrists in the proximal-distal direction (17.1 vs 7.2 mm). We postulate that the mismatch in the COR location and behavior may be associated with increased loading of the TWA components, leading to an increase in the risk of component and/or interface failure.

The Effect of Proximal Hamate Osteotomy on Carpal Kinematics for Reconstruction of Proximal Pole Scaphoid Nonunion With Avascular Necrosis

Background: The purpose of this study is to determine the effects of proximal hamate transfer for proximal pole scaphoid reconstruction upon carpal kinematics. Methods: Eight fresh-frozen cadaveric wrists underwent evaluation of their radiocarpal and midcarpal motion after proximal hamate osteotomy. A wrist simulator was used to apply cyclical tension to the flexor carpi ulnaris (FCU), flexor carpi radialis (FCR), extensor carpi ulnaris (ECU), and extensor carpi radialis longus and brevis stitched together (ECR). Kinematic motion was captured using Moiré Phase Tracking 3-dimensional motion-tracking sensors (MPT, Metria Innovation, Inc, Milwaukee, Wisconsin) to evaluate the lunocapitate and scapholunate angles for each condition. Results: During wrist flexion-extension and radial-ulnar deviation, there were no statistically significant differences about the lunocapitate or scapholunate axis between the intact and post-hamate osteotomy conditions. Conclusions: The harvest of the proximal hamate for proximal pole scaphoid reconstruction does not appear to adversely affect wrist kinematics.

Anatomical anterior and posterior reconstruction for scapholunate dissociation: preliminary outcome in ten patients

This study reviews the efficacy of a reconstruction to address scapholunate dissociation using an anterior and posterior approach with a hybrid synthetic tape/tendon weave between the trapezium, scaphoid, lunate and radius: an anatomical front and back (ANAFAB) repair. This repair is a compilation of the components of a number of previously reported repair techniques, and based on published kinematic evidence. It aims to restore the anatomical mechanical constraints on both anterior and posterior aspects of the carpus. Patients were immobilized in a cast for 6 weeks, but no stabilizing wires were used. Ten patients have undergone the reconstruction and were assessed at a minimum 24-month follow-up. They achieved excellent realignment of the carpus, a postoperative median scapholunate gap of 3 mm and a recovery of more than 75% of grip strength and range of motion. No patient required secondary surgery or treatment related to the carpal stabilization. Level of evidence: IV.

The Relationship Between the Tensile and the Torsional Properties of the Native Scapholunate Ligament and Carpal Kinematics

PURPOSE

The purpose of this exploratory study was to examine the relationship between the tensile and the torsional properties of the native scapholunate interosseous ligament (SLIL) and kinematics of the scaphoid and lunate of an intact wrist during passive radioulnar deviation.

METHODS

Eight fresh-frozen cadaveric specimens were transected at the elbow joint and loaded into a custom jig. Kinematic data of the scaphoid and lunate were acquired in a simulated resting condition for 3 wrist positions-neutral, 10° radial deviation, and 30° ulnar deviation-using infrared-emitting rigid body trackers. The SLIL bone-ligament-bone complex was then resected and loaded on a materials testing machine. Specimens underwent cyclic torsional and tensile testing and SLIL tensile and torsional laxity were evaluated. Correlations between scaphoid and lunate rotations and SLIL tensile and torsional properties were determined using Pearson correlation coefficients.

RESULTS

Ulnar deviation of both the scaphoid and the lunate were found to decrease as the laxity of SLIL in torsion increased. In addition, the ratio of lunate flexion-extension to radial-ulnar deviation was found to increase with increased SLIL torsional rotation.

CONCLUSIONS

Our findings support the theory that there is a relationship between scapholunate kinematics and laxity at the level of the interosseous ligaments.

CLINICAL RELEVANCE

Laxity and, specifically, the tensile and torsional properties of an individual's native SLIL should guide reconstruction using a graft material that more closely replicates the individual's native SLIL properties.

A novel staged wrist sensorimotor rehabilitation program for a patient with triangular fibrocartilage complex injury: A case report

STUDY DESIGN

Case report.

INTRODUCTION

Studies have highlighted the sensory innervations and stabilizing role of forearm muscles on wrist joint and implications to wrist sensorimotor rehabilitation. This case explored the novel incorporation of dart-throwing motion and proprioceptive neuromuscular facilitation in wrist sensorimotor rehabilitation.

PURPOSE OF THE STUDY

To describe and evaluate a staged wrist sensorimotor rehabilitation program for a patient with triangular fibrocartilage complex (TFCC) injury.

METHODS

The patient participated in the staged program for 9 sessions over a 3-month period. Treatment involved neuromuscular strengthening at the wrist and movement normalization of the upper extremity. Outcome measures were grip strength, visual analog scale, joint position sense, Quick Disabilities of the Arm, Shoulder and Hand, and patient-rated wrist evaluation.

RESULTS

The patient showed improvement in all outcome measures. Most outcomes exceeded the established minimal clinically important difference values.

DISCUSSION

The results suggest that dart-throwing motion and proprioceptive neuromuscular facilitation are beneficial in rehabilitation of TFCC injury.

CONCLUSIONS

This is the first study that incorporated dart-throwing motion and proprioceptive neuromuscular facilitation in the sensorimotor rehabilitation of TFCC injury and yielded promising results. There is a need to further evaluate the program in prospective randomized controlled trial recruiting a larger group of patients with TFCC injury.

Dynamic MRI of the wrist in less than 20 seconds: normal midcarpal motion and reader reliability

OBJECTIVE

To describe the normal motion pattern at the midcarpal compartment during active radial-ulnar deviation of the wrist using dynamic MRI, and to determine the observer performance for measurements obtained in asymptomatic volunteers.

METHODS

Dynamic MRI of 35 wrists in 19 asymptomatic volunteers (age mean 30.4 years, SD 8.6) was performed during active radial-ulnar deviation using a fast gradient-echo pulse sequence with 315 ms temporal resolution (acquisition time, 19 s). Two independent readers measured the transverse translation of the trapezium at the scaphotrapezium joint (STJ) and the capitate-to-triquetrum distance (CTD). Relationships between these measurements and laterality, sex, lunate type, and wrist kinematic pattern were evaluated.

RESULTS

At the STJ, the trapezium moved most in radial deviation, with an overall translation of 2.3 mm between ulnar and radial deviation. Mean CTD measurements were the greatest in ulnar deviation and varied 2.4 mm between ulnar and radial deviation. Mean CTD was greater in men than women in the neutral position (p = 0.019), and in wrists with type II lunate morphology during radial and ulnar deviation (p = 0.001, p = 0.014). There were no significant differences in trapezium translation or CTD with wrist laterality and kinematic pattern. Intraobserver and interobserver correlation coefficients were 0.97 and 0.87 for trapezium translation and 0.84 and 0.67 for CTD.

CONCLUSION

This study is the first to demonstrate the performance of dynamic MRI to quantify STJ motion and CTD. Dynamic MRI with a short acquisition time may be used as a tool to supplement static MRI in evaluation of the midcarpal compartment.

Predicting Carpal Bone Kinematics Using an Expanded Digital Database of Wrist Carpal Bone Anatomy and Kinematics

The wrist can be considered a 2 degrees-of-freedom joint with all movements reflecting the combination of flexion-extension and radial-ulnar deviation. Wrist motions are accomplished by the kinematic reduction of the 42 degrees-of-freedom of the individual carpal bones. While previous studies have demonstrated the minimal motion of the scaphoid and lunate as the wrist moves along the dart-thrower's path or small relative motion between hamate-capitate-trapezoid, an understanding of the kinematics of the complete carpus across all wrist motions remains lacking. To address this, we assembled an open-source database of in vivo carpal motions and developed mathematical models of the carpal kinematics as a function of wrist motion. Quadratic surfaces were trained for each of the 42-carpal bone degrees-of-freedom and the goodness of fits were evaluated. Using the models, paths of wrist motion that generated minimal carpal rotations or translations were determined. Model predictions were best for flexion-extension, radial-ulnar deviation, and volar-dorsal translations for all carpal bones with R ²  > 0.8, while the estimates were least effective for supination-pronation with R ²  < 0.6. The wrist path of motion's analysis indicated that the distal row of carpal bones moves rigidly together (<3° motion), along the anatomical axis of wrist motion, while the bones in the proximal row undergo minimal motion when the wrist moves in a path oblique to the main axes. The open-source dataset along with its graphical user interface and mathematical models should facilitate clinical visualization and enable new studies of carpal kinematics and function. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2661-2670, 2019.

Real-time three-dimensional MRI for the assessment of dynamic carpal instability

Background

Carpal instability is defined as a condition where wrist motion and/or loading creates mechanical dysfunction, resulting in weakness, pain and decreased function. When conventional methods do not identify the instability patterns, yet clinical signs of instability exist, the diagnosis of dynamic instability is often suggested to describe carpal derangement manifested only during the wrist’s active motion or stress. We addressed the question: can advanced MRI techniques provide quantitative means to evaluate dynamic carpal instability and supplement standard static MRI acquisition? Our objectives were to (i) develop a real-time, three-dimensional MRI method to image the carpal joints during their active, uninterrupted motion; and (ii) demonstrate feasibility of the method for assessing metrics relevant to dynamic carpal instability, thus overcoming limitations of standard MRI.

Methods

Twenty wrists (bilateral wrists of ten healthy participants) were scanned during radial-ulnar deviation and clenched-fist maneuvers. Images resulting from two real-time MRI pulse sequences, four sparse data-acquisition schemes, and three constrained image reconstruction techniques were compared. Image quality was assessed via blinded scoring by three radiologists and quantitative imaging metrics.

Results

Real-time MRI data-acquisition employing sparse radial sampling with a gradient-recalled-echo acquisition and constrained iterative reconstruction appeared to provide a practical tradeoff between imaging speed (temporal resolution up to 135 ms per slice) and image quality. The method effectively reduced streaking artifacts arising from data undersampling and enabled the derivation of quantitative measures pertinent to evaluating dynamic carpal instability.

Conclusion

This study demonstrates that real-time, three-dimensional MRI of the moving wrist is feasible and may be useful for the evaluation of dynamic carpal instability.

Role of Ligament Stabilizers of the Proximal Carpal Row in Preventing Dorsal Intercalated Segment Instability: A Cadaveric Study

BACKGROUND

Isolated injuries of the scapholunate interosseous ligament (SLIL) are insufficient to produce dorsal intercalated segment instability. There is no consensus about which additional ligamentous stabilizers are critical determinants of dorsal intercalated segment instability. The aim of this study was to evaluate the role of the long radiolunate (LRL), scaphotrapeziotrapezoid (STT), and dorsal intercarpal (DIC) ligaments in preventing dorsal intercalated segment instability.

METHODS

Thirty fresh-frozen forearms were randomized to 5 ligament section sequences to study the SLIL, LRL, STT, and DIC ligaments. The DIC-lunate insertion (DIC) and scaphoid insertion (DIC) were studied separately; the DIC insertions on the trapezium and triquetrum were left intact. Loaded posteroanterior and lateral fluoroscopic images were obtained at baseline and repeated after each ligament was sectioned. After each sequence, the wrists were loaded cyclically (71 N). The radiolunate angle was measured with load. Dorsal intercalated segment instability was defined as an increase of >15° in the radiolunate angle compared with baseline.

RESULTS

Division of the SLIL did not increase the radiolunate angle. Section of the SLIL+LRL or SLIL+DIC significantly increased the radiolunate angle but did not produce dorsal intercalated segment instability. Section of the SLIL+STT or SLIL+DIC+DIC produced dorsal intercalated segment instability.

CONCLUSIONS

In order to produce dorsal intercalated segment instability, complete scapholunate injuries require the disruption of at least 1 critical ligament stabilizer of the scaphoid or lunate (the STT or DIC+DIC).

CLINICAL RELEVANCE

When treating SLIL tears with dorsal intercalated segment instability, techniques to evaluate the volar and dorsal critical stabilizers of the proximal carpal row should be considered.

Does Object Height Affect the Dart Throwing Motion Angle during Seated Activities of Daily Living?

Complex wrist motions are needed to complete various daily activities. Analyzing the multidimensional motion of the wrist is crucial for understanding our functional movement. Several studies have shown that numerous activities of daily livings (ADLs) are performed using an oblique plane of wrist motion from radial-extension to ulnar-flexion, named the Dart Throwing Motion (DTM) plane. To the best of our knowledge, the DTM plane angle performed during ADLs has not been compared between different heights (e.g. table, shoulder and head height), as is common when performing day-to-day tasks. In this study, we compared DTM plane angles when performing different ADLs at three different heights and examined the relationship between DTM plane angles and limb position. We found that height had a significant effect on the DTM plane angles - the mean DTM plane angle was greater at the lower level compared to the mid and higher levels. A significant effect of shoulder orientation on mean DTM plane angles was shown in the sagittal and coronal planes. Our findings support the importance of training daily tasks at different heights during rehabilitation following wrist injuries, in order to explore a large range of DTM angles, to accommodate needs of common ADLs.

Scapholunate Ligament Internal Brace 360 Tenodesis (SLITT) Procedure: A Biomechanical Study

Background  Twelve paired fresh frozen cadaveric wrists were randomized to a 360-degree tenodesis repair group or the 360-degree tenodesis repair with an internal brace (suture tape) construct. Case Description  The specimens were preloaded to 5 N and subsequently biomechanically loaded to failure, at a rate of 0.1 mm/s on a jig that allowed for axial load. The maximum load and mode of failure were recorded. Load to failure in the 360 tenodesis group with internal brace was 283.47 ± 100.25 N, compared with the 360 tenodesis group only, whose yield strength was 143.61 ± 90.54 N. The mode of failure within the internal brace construct was either through knot slippage, graft disruption, or bone separation from strength testing construct. The 360 tenodesis group tended to fail via graft slippage or graft rupture. Literature Review  The management of scapholunate instability can be a difficult problem to treat. Traditionally, many of the surgical reconstructions have focused upon dorsal ligament reconstruction with Kirschner (K) wire fixation. This results in prolonged immobilization of the wrist with varied outcomes, in part due to the multiaxial instability that may persist due to concomitant volar ligament disruption. To address this instability, surgical techniques have been devised that address both the volar and dorsal ligament injuries. Clinical Relevance  Scapholunate reconstruction with a 360-degree tenodesis and internal brace augmentation (SLITT procedure) provided superior biomechanical stability than tenodesis alone.

A principal component analysis-based framework for statistical modeling of bone displacement during wrist maneuvers

We present a method for the statistical modeling of the displacements of wrist bones during the performance of coordinated maneuvers, such as radial-ulnar deviation (RUD). In our approach, we decompose bone displacement via a set of basis functions, identified via principal component analysis (PCA). We utilized MRI wrist scans acquired at multiple static positions for deriving these basis functions. We then utilized these basis functions to compare the displacements undergone by the bones of the left versus right wrist in the same individual, and between bones of the wrists of men and women, during the performance of the coordinated RUD maneuver. Our results show that the complex displacements of the wrist bones during RUD can be modeled with high reliability with just 5 basis functions, that captured over 91% of variation across individuals. The basis functions were able to predict intermediate wrist bone poses with an overall high accuracy (mean error of 0.26 mm). Our proposed approach found statistically significant differences between bone displacement trajectories in women versus men, however, did not find significant differences in those of the left versus right wrist in the same individual. Our proposed method has the potential to enable detailed analysis of wrist kinematics for each sex, and provide a robust framework for characterizing the normal and pathologic displacement of the wrist bones, such as in the context of wrist instability.

Wrist Plane of Motion and Range During Daily Activities

OBJECTIVE. The dart-throwing motion (DTM) is a multiplane wrist motion that is needed for many daily occupations. Mobilization along the DTM plane may be essential for rehabilitation after wrist injury, but DTM angles are reported for the dominant hand alone, so their relevance to injury in the nondominant hand cannot be surmised. The aim of this study was to quantify the DTM plane angles for both hands during different activities of daily living (ADLs).

METHOD. Forty-three healthy participants wore a twin-axis electrogoniometer during ADLs.

RESULTS. No significant differences were found between the DTM plane angles of the dominant (20°–45°) and nondominant (15°–40°) hands. These angles varied by task and across participants.

CONCLUSION. The DTM plane is a functional motion used by both hands during ADLs. Because the DTM plane angle differs among hands, tasks, and individual clients, wrist rehabilitation involving the DTM plane should not be limited to a singular DTM plane angle.

Scapholunate Ligament Internal Brace 360-Degree Tenodesis (SLITT) Procedure

Background  Scapholunate (SL) joint instability is one of the most common injuries of the wrist and may result from a fall or high-energy mechanism on the outstretched hand. The purpose of this case report is to describe the outcome of a 360-degree tenodesis to the SL joint with an internal brace (SLITT) for the treatment of SL instability. Case Description  A 42-year-old male patient underwent SL ligament reconstruction with the SLITT procedure 12 months after injury. Given the intrinsic stability of the reconstruction, Kirschner (K) wires were not used and an early range of motion protocol was initiated. Thirteen months after his reconstruction, he was back at work with maintenance of his carpal alignment. Discussion  Since its initial description, a myriad of different surgical techniques for SL instability have been devised with varied success. These include capsular shrinkage, dorsal capsulodesis, reduction-association with a screw of the scapholunate joint (RASL), scapholunate axis method (SLAM), bone ligament bone grafts, and a variety of tendon reconstructions. Possible explanations for this varied outcome may be related to the use of soft tissue reconstructions for irreducible injuries and reconstruction of only the dorsal SL ligament. In addition, many of these techniques involve prolonged immobilization with the use of K-wires. Clinical Relevance  The SLITT procedure reconstructs both the volar and dorsal SL ligament. Given the added stability afforded by intrinsic bracing, we feel that this reconstruction may permit earlier range of motion without the need for K-wire stabilization.

Trabecular bone patterning across the human hand

Hand bone morphology is regularly used to link particular hominin species with behaviors relevant to cognitive/technological progress. Debates about the functional significance of differing hominin hand bone morphologies tend to rely on establishing phylogenetic relationships and/or inferring behavior from epigenetic variation arising from mechanical loading and adaptive bone modeling. Most research focuses on variation in cortical bone structure, but additional information about hand function may be provided through the analysis of internal trabecular structure. While primate hand bone trabecular structure is known to vary in ways that are consistent with expected joint loading differences during manipulation and locomotion, no study exists that has documented this variation across the numerous bones of the hand. We quantify the trabecular structure in 22 bones of the human hand (early/extant modern Homo sapiens) and compare structural variation between two groups associated with post-agricultural/industrial (post-Neolithic) and foraging/hunter-gatherer (forager) subsistence strategies. We (1) establish trabecular bone volume fraction (BV/TV), modulus (E), degree of anisotropy (DA), mean trabecular thickness (Tb.Th) and spacing (Tb.Sp); (2) visualize the average distribution of site-specific BV/TV for each bone; and (3) examine if the variation in trabecular structure is consistent with expected joint loading differences among the regions of the hand and between the groups. Results indicate similar distributions of trabecular bone in both groups, with those of the forager sample presenting higher BV/TV, E, and lower DA, suggesting greater and more variable loading during manipulation. We find indications of higher loading along the ulnar side of the forager sample hand, with high site-specific BV/TV distributions among the carpals that are suggestive of high loading while the wrist moves through the 'dart-thrower's' motion. These results support the use of trabecular structure to infer behavior and have direct implications for refining our understanding of human hand evolution and fossil hominin hand use.

Three-dimensional kinematics of the lunate, hamate, capitate and triquetrum with type 1 or 2 lunate morphology

The purpose of this study was to investigate the differences in three-dimensional carpal kinematics between type 1 and 2 lunates. We studied 15 instances of wrist flexion to extension (nine type 1, six type 2), 13 of radial to ulnar deviation (seven type 1, six type 2), and 12 of dart-throwing motion (six each of type 1 and 2) in 25 normal participants based on imaging with computerized tomography. Mean proximal translation of the distal articular midpoint of the triquetrum relative to type 2 lunates during wrist radioulnar deviation was 2.9 mm (standard deviation (SD) 0.7), which was significantly greater than for type 1 lunates, 1.6 mm (SD 0.6). The hamate contacted the lunate in ulnar deviation and ulnar flexion of wrists with type 2 lunates but not with type 1. We conclude that the four-corner kinematics of the wrist joint are different between type 1 and 2 lunates.