Surgeon preferences in the treatment of thumb carpometacarpal osteoarthritis.

BACKGROUND: Primary thumb carpometacarpal (CMC) osteoarthritis is one of the most common conditions encountered by hand surgeons. Of the vast number of operations that have been proposed, none have demonstrated results significantly superior to trapeziectomy alone. AIM: The purpose of our study was to determine why surgeons opt for their technique in treating CMC arthritis. METHODS: A cross-sectional survey of active members of the American Society for Surgery of the Hand was conducted to evaluate the reasons behind their preferred technique in the treatment of isolated thumb CMC arthritis. Surgeons were contacted by e-mail once and provided with a link to a de-identified survey consisting of 5 treatment questions and 5 demographic questions. RESULTS: Of 950 responses were received. 40.5% of surgeons preferred trapeziectomy + ligament reconstruction tendon interposition (LRTI), followed by trapeziectomy + suspensionplasty (28.2%), suture button suspension (5.9 %), trapeziectomy alone (4.6%), prosthetic arthroplasty (3.2%), arthrodesis (1.1%), and other (6.6%). Proponents of trapeziectomy + LRTI cited familiarity (73.2%), exposure during fellowship (48.8%) and less proximal migration (60%) to be the main reasons affecting their decision. Surgeons who preferred trapeziectomy + suspensionplasty most reported simplicity (74.9%), fewer complications (45.3%), less proximal migration (43.8%), and avoidance of autogenous tissue harvest (42.7%). Advocates of suture button suspension cited avoidance of autogenous tissue harvest (80.4%), shorter immobilization (76.8%), and quicker recovery (73.2%) with their technique. Advocates of trapeziectomy alone cited simplicity (97.7%), fewer complications (86.4%), and avoidance of autogenous tissue harvest (59.1%). In their comments, 45% of surgeons choosing trapeziectomy alone cited evidence as an additional rationale. Advocates of prosthetic arthroplasty cited improved pinch strength (83.3%) and improved range of motion (63.3%), while those preferring arthrodesis cited better pinch strength (90%) and frequently in their comments, durability. Of the surgeons who preferred a technique other than LRTI, 41.8% reported they had tried LRTI in the past, citing complexity of the procedure, flexor carpi radialis harvest, and longer operative time as reasons for moving on. CONCLUSION: Our study provides an update on current treatment trends and offers new insight into the reasons behind surgeons' decision making in the management of thumb carpometacarpal osteoarthritis. Despite strong Level 1 evidence supporting the use of trapeziectomy alone, our findings demonstrate that most surgeons continue to supplement trapeziectomy with other techniques such as LRTI or suspensionplasty. Several factors including familiarity, personal experience (Level 4 evidence), and comfort may be more influential than Level 1 evidence in determining the techniques in a surgeon's armamentarium. Further prospective studies are needed to determine the optimal technique for surgical management of Eaton stages II-IV CMC arthritis and how these studies will affect surgeons' choice.

The Perceived Value of Same-Sex or Same-Race Mentors and Role Models in Academic Medicine.

This study aims to describe the perception of need for same-sex and same-race mentorship and role models at evolving stages of a medical career and to explore whether these differences affect career choices within the field of medicine. A total of 326 medical students, 309 resident physicians, and 200 faculty attending physicians at the University of California, Davis School of Medicine completed an online survey focused on their perceived value of same-sex and same-race mentorship throughout their stages of medical training and practice. The top three factors influencing specialty choice were lifestyle, time commitment, and supportive department. Although most respondents did not believe same-sex or same-race mentors or role models influenced their specialty choice, there were significant differences in the perceived importance and value of gender or race concordance between male versus female and white versus nonwhite populations. (Journal of Surgical Orthopaedic Advances 33(1):041-048, 2024).

Current trends in the prevention of adhesions after zone 2 flexor tendon repair.

Treating flexor tendon injuries within the digital flexor sheath (commonly referred to as palmar hand zone 2) presents both technical and logistical challenges. Success hinges on striking a delicate balance between safeguarding the surgical repair for tendon healing and initiating early rehabilitation to mitigate the formation of tendon adhesions. Adhesions between tendon slips and between tendons and the flexor sheath impede tendon movement, leading to postoperative stiffness and functional impairment. While current approaches to flexor tendon repair prioritize maximizing tendon strength for early mobilization and adhesion prevention, factors such as pain, swelling, and patient compliance may impede postoperative rehabilitation efforts. Moreover, premature mobilization could risk repair failure, necessitating additional surgical interventions. Pharmacological agents offer a potential avenue for minimizing inflammation and reducing adhesion formation while still promoting normal tendon healing. Although some systemic and local agents have shown promising results in animal studies, their clinical efficacy remains uncertain. Limitations in these studies include the relevance of chosen animal models to human populations and the adequacy of tools and measurement techniques in accurately assessing the impact of adhesions. This article provides an overview of the clinical challenges associated with flexor tendon injuries, discusses current on- and off-label agents aimed at minimizing adhesion formation, and examines investigational models designed to study adhesion reduction after intra-synovial flexor tendon repair. Understanding the clinical problem and experimental models may serve as a catalyst for future research aimed at addressing intra-synovial tendon adhesions following zone 2 flexor tendon repair.

Relationships between diagnostic imaging of first carpometacarpal osteoarthritis and pain, functional status, and disease progression: A systematic review.

OBJECTIVE: To systematically review the association of pain, function, and progression in first carpometacarpal (CMC) osteoarthritis (OA) with imaging biomarkers and radiography-based staging. DESIGN: Database searches in PubMed, Embase, and the Cochrane Library, along with citation searching were conducted in accordance with published guidance. Data on the association of imaging with pain, functional status, and disease progression were extracted and synthesized, along with key information on study methodology such as sample sizes, use of control subjects, study design, number of image raters, and blinding. Methodological quality was assessed using National Heart, Lung, and Blood Institute tools. RESULTS: After duplicate removal, a total of 1969 records were screened. Forty-six articles are included in this review, covering a total of 28,202 study participants, 7263 with first CMC OA. Osteophytes were found to be one of the strongest biomarkers for pain across imaging modalities. Radiographic findings alone showed conflicting relationships with pain. However, Kellgren-Lawrence staging showed consistent associations with pain in various studies. Radiographic, sonographic, and MRI findings and staging showed little association to tools evaluating functional status across imaging modalities. The same imaging methods showed limited ability to predict progression of first CMC OA. A major limitation was the heterogeneity in the study base, limiting synthesis of results. CONCLUSION: Imaging findings and radiography-based staging systems generally showed strong associations with pain, but not with functional status or disease progression. More research and improved imaging techniques are needed to help physicians better manage patients with first CMC OA.

The effect of shoulder prosthesis stem length on failure due to torsional loading. A biomechanical study in composite humeri.

Background: Shoulder arthroplasty is becoming increasingly common. With evolving implant designs, multiple humeral stem options exist for the surgeon to choose from. New stemless and short-stem systems are modular, remove less native bone stock, and better adapt to patient anatomy. It has been suggested that shorter stem implants may be protective against periprosthetic fracture; however, this has not been mechanistically evaluated. Therefore, this study aimed to biomechanically test synthetic humeri with long-stem, short-stem, and stemless arthroplasty components in a torsional manner to evaluate their response to loading and characterize failure. Methods: Twenty-four synthetic humeri were implanted with long stem, short stem, or stemless uncemented prosthesis, 8 in each group. Humeri were mounted in a custom testing jig with a morse taper interfacing with a mechanical testing system. After a 20N axial force, specimens were torsionally loaded to failure at 15 degrees/sec, with 50 Hz collection. Torque vs. rotation curves were generated for each specimen, and stiffness, yield, ultimate strength, and failure load were measured. ANOVA and post hoc pairwise comparisons were used to assess effect of stem type on mechanical test variable. The association of the stem type with fracture type was analyzed by a Fisher's Exact test. Statistical significance was set at P < .05. Results: During torsional loading, long-stem implants were significantly stiffer than short or stemless implants. The angle of implant yielding was similar across stem designs; however, stemless implants had a lower yield torque. This correlated with a decreased yield energy in stemless compared to short stems as well. Maximum torque and failure torque was also significantly higher in short-stem and long-stem implants compared to stemless. Discussion: Periprosthetic fractures in shoulder arthroplasty are a concern in low-energy trauma, and stem design likely plays a significant role in early implant-bone failure. Our results suggest stemless implants under torsional load fail at lower stress and are less stiff than stemmed implants. The failure mechanism of stemless implants through metaphyseal cancellous bone emphasizes the effect bone quality has on implant fixation. There is likely a balance of torsional stability to survive physiologic loads while minimizing diaphyseal stress and risk of diaphyseal periprosthetic fracture. This combined with revision and fixation options represent decisions the surgeon is faced with when performing shoulder arthroplasty.

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.

Interdisciplinary consensus statements on imaging of DRUJ instability and TFCC injuries.

OBJECTIVES: The purpose of this agreement was to establish evidence-based consensus statements on imaging of distal radioulnar joint (DRUJ) instability and triangular fibrocartilage complex (TFCC) injuries by an expert group using the Delphi technique. METHODS: Nineteen hand surgeons developed a preliminary list of questions on DRUJ instability and TFCC injuries. Radiologists created statements based on the literature and the authors' clinical experience. Questions and statements were revised during three iterative Delphi rounds. Delphi panelists consisted of twenty-seven musculoskeletal radiologists. The panelists scored their degree of agreement to each statement on an 11-item numeric scale. Scores of "0," "5," and "10" reflected complete disagreement, indeterminate agreement, and complete agreement, respectively. Group consensus was defined as a score of "8" or higher for 80% or more of the panelists. RESULTS: Three of fourteen statements achieved group consensus in the first Delphi round and ten statements achieved group consensus in the second Delphi round. The third and final Delphi round was limited to the one question that did not achieve group consensus in the previous rounds. CONCLUSIONS: Delphi-based agreements suggest that CT with static axial slices in neutral rotation, pronation, and supination is the most useful and accurate imaging technique for the work-up of DRUJ instability. MRI is the most valuable technique in the diagnosis of TFCC lesions. The main indication for MR arthrography and CT arthrography are Palmer 1B foveal lesions of the TFCC. CLINICAL RELEVANCE STATEMENT: MRI is the method of choice for assessing TFCC lesions, with higher accuracy for central than peripheral abnormalities. The main indication for MR arthrography is the evaluation of TFCC foveal insertion lesions and peripheral non-Palmer injuries. KEY POINTS: • Conventional radiography should be the initial imaging technique in the assessment of DRUJ instability. CT with static axial slices in neutral rotation, pronation, and supination is the most accurate method for evaluating DRUJ instability. • MRI is the most useful technique in diagnosing soft-tissue injuries causing DRUJ instability, especially TFCC lesions. • The main indications for MR arthrography and CT arthrography are foveal lesions of the TFCC.

Pre-operative imaging for surgical decision-making and the frequency of wrist arthrodesis and carpectomy procedures: a scoping review.

OBJECTIVES: Our objectives were to (1) analyze the imaging modalities utilized pre-operatively that influence surgical decision-making for wrist arthrodesis and carpectomy procedures and (2) determine the type and frequency of these procedures for the treatment of wrist arthritis. MATERIALS AND METHODS: This review was performed according to the guidelines of PRISMA Extension for Scoping Reviews. Using PubMed, Embase, and Scopus, peer-reviewed literature from 2011 to 2022 was searched for use of imaging in pre-operative decision-making for wrist arthrodesis and carpectomy surgical procedures. Data were compiled to determine the type(s) of imaging modalities used pre-operatively and types of surgical techniques reported in the literature. RESULTS: Of 307 articles identified, 35 articles satisfied eligibility criteria, with a total of 1377 patients (68% men; age mean, 50.9 years [range, 10-81]) and 1428 wrist surgical interventions. Radiography was reported for pre-operative planning in all articles for all patients. Pre-operative cross-sectional imaging was reported in 2 articles (5.7%), but no articles reported detailed data on how CT or MRI influenced pre-operative wrist arthrodesis and carpectomy procedure decision-making. A dozen different types of surgical techniques were reported. The four most common procedures were four-corner arthrodesis with scaphoid excision (846, 59%), proximal row carpectomy (239, 17%), total wrist arthrodesis (130, 9%), and scaphocapitate arthrodesis (53, 4%). CONCLUSION: Radiography is always used in pre-operative decision-making, but the literature lacks data on the influence of CT and MRI for selecting among a dozen different types of wrist arthrodesis and carpectomy procedures.

Advanced Arthritis of the Carpus: Preoperative Planning Practices of 337 Hand Surgeons.

Background Surgical procedure selection for carpal arthritis depends on which articular surfaces are affected, but there is no consensus on how to preoperatively evaluate cartilage surfaces. Despite advances in cross-sectional imaging, the utility of advanced imaging for preoperative decision-making has not been well established. Objectives Our objective was to assess if there is an added value to presurgical advanced imaging or diagnostic procedures in planning for carpal arthrodesis or carpectomy and to determine what imaging or diagnostic procedures influence surgical treatment options. Methods A seven-question survey was sent to 2,400 hand surgeons. Questions assessed which articular surfaces surgeons consider important for decision-making, which imaging modalities surgeons employ, and how often surgeons utilize diagnostic arthroscopy before performing carpectomy or arthrodesis procedures. Results A total of 337 (14%) surveys were analyzed. The capitolunate articulation (alone or in combination) was most frequently reported to impact surgical decision-making (48.1%). Most surgeons (86.6%) reported that standard plain radiographs are usually sufficient. Few surgeons reported always obtaining magnetic resonance imaging (MRI) or computed tomography (CT), with 44.2% of surgeons believing that MRI is never useful and 38.4% believing that CT is never useful. Most surgeons (68.2%) reported that they never perform wrist arthroscopy as part of their decision-making process. Conclusions This study provides information on the decision-making process in the surgical management of carpal arthritis. Given advances in cross-sectional imaging, further studies are needed to determine the utility of MRI and CT for the planning of surgical procedures in the treatment of arthritis of the carpus. Level of Evidence Level 4.

Interdisciplinary consensus statements on imaging of scapholunate joint instability.

OBJECTIVES: The purpose of this agreement was to establish evidence-based consensus statements on imaging of scapholunate joint (SLJ) instability by an expert group using the Delphi technique. METHODS: Nineteen hand surgeons developed a preliminary list of questions on SLJ instability. Radiologists created statements based on the literature and the authors' clinical experience. Questions and statements were revised during three iterative Delphi rounds. Delphi panellists consisted of twenty-seven musculoskeletal radiologists. The panellists scored their degree of agreement to each statement on an eleven-item numeric scale. Scores of '0', '5' and '10' reflected complete disagreement, indeterminate agreement and complete agreement, respectively. Group consensus was defined as a score of '8' or higher for 80% or more of the panellists. RESULTS: Ten of fifteen statements achieved group consensus in the second Delphi round. The remaining five statements achieved group consensus in the third Delphi round. It was agreed that dorsopalmar and lateral radiographs should be acquired as routine imaging work-up in patients with suspected SLJ instability. Radiographic stress views and dynamic fluoroscopy allow accurate diagnosis of dynamic SLJ instability. MR arthrography and CT arthrography are accurate for detecting scapholunate interosseous ligament tears and articular cartilage defects. Ultrasonography and MRI can delineate most extrinsic carpal ligaments, although validated scientific evidence on accurate differentiation between partially or completely torn or incompetent ligaments is not available. CONCLUSIONS: Delphi-based agreements suggest that standardized radiographs, radiographic stress views, dynamic fluoroscopy, MR arthrography and CT arthrography are the most useful and accurate imaging techniques for the work-up of SLJ instability. KEY POINTS: • Dorsopalmar and lateral wrist radiographs remain the basic imaging modality for routine imaging work-up in patients with suspected scapholunate joint instability. • Radiographic stress views and dynamic fluoroscopy of the wrist allow accurate diagnosis of dynamic scapholunate joint instability. • Wrist MR arthrography and CT arthrography are accurate for determination of scapholunate interosseous ligament tears and cartilage defects.

The Biomechanical Effects of Simulated Radioscapholunate Fusion With Distal Scaphoidectomy, 4-Corner Fusion With Complete Scaphoidectomy, and Proximal Row Carpectomy Compared to the Native Wrist.

PURPOSE: To determine the effect of simulated radioscapholunate fusion with distal scaphoid excision (RSLF+DSE), 4-corner fusion with scaphoidectomy (4-CF), and proximal row carpectomy (PRC) on the wrist's range of motion (ROM), contact pressure, and contact force in a cadaveric model. METHODS: Ten freshly frozen cadaveric wrists were tested under 4 sequential conditions: native wrist, RSLF+DSE, 4-CF, and PRC. The simulated fusions were performed using two 1.6-mm Kirschner wires. The ROM in the flexion-extension and radioulnar deviation planes was evaluated. Contact area, contact pressure, and contact force were measured at the scaphocapitolunate joint for the RSLF+DSE simulation and radiocarpal joint for the 4-CF and PRC simulations. Mechanical testing was performed using a 35-N uniaxial load and pressure-sensitive film. RESULTS: The RSLF+DSE and 4-CF groups had a decreased wrist arc ROM compared with the native wrist. The PRC group had a greater wrist arc ROM compared with the RSLF+DSE and 4-CF groups, but compared to the native wrist, it demonstrated a mildly decreased wrist arc ROM. The carpal pressure and contact force were significantly increased in the RSLF+DSE, 4-CF, and PRC groups compared with those in the native wrist. The RSLF+DSE group had the smallest increase in the carpal pressure and contact force, whereas the PRC group had the greatest increase. CONCLUSIONS: Our study validates previous findings that PRC is motion-conserving but has the greatest contact force, whereas RSLF-DSE and 4-CF may cause a decrease in the ROM but have lower contact forces. CLINICAL RELEVANCE: Understanding the underlying native wrist biomechanics and alterations following different surgical treatments may assist hand surgeons in their clinical decision making for the treatment of stage II scapholunate advanced collapse.

The Biomechanical Effects of Augmentation With Flat Braided Suture on Dorsal Intercarpal Ligament Capsulodesis for Scapholunate Instability.

PURPOSE: Selecting treatment for scapholunate (SL) instability is notoriously difficult. Many methods of reconstruction have been described, but no procedure demonstrates clear superiority. New methods proposed use internal bracing (IB) with suture anchors and flat braided suture (FBS), alone or as an augmentation with tendon autograft for SL ligament injuries. Our goal was to use computed tomography (CT) to analyze alignment of the SL joint after 3 different modes of fixation of SL instability: after reconstruction with IB incorporating either tendon autograft or the dorsal intercarpal ligament (DICL), or DICL capsulodesis without FBS. METHODS: Ten fresh-frozen, matched-pair, forearm-to-hand specimens were used. Serial sectioning of the SL stabilizing ligaments was performed and the SL interval was measured with CT. We reconstructed the SL ligament with DICL capsulodesis alone (DICL) or with IB augmented with either tendon autograft (IB plus T) or DICL (DICL plus IB). The SL interval was measured with CT. Specimens underwent 500 weighted cycles on a jig and were reimaged. Differences in SL interval after repair and cycling were compared. RESULTS: Dorsal intercarpal ligament capsulodesis augmented with IB best maintained the SL interval before and after cycling. Dorsal intercarpal ligament capsulodesis alone was inferior to DICL plus IB and IB plus T both before and after cycling. CONCLUSIONS: Dorsal intercarpal ligament capsulodesis augmented with IB appears to maintain better SL joint reduction than IB with tendon autograft. CLINICAL RELEVANCE: This work serves as a necessary step for further study of the biomechanical strength and clinical application of FBS technology in the reconstruction of SL instability. Flat braided suture augmentation of DICL capsulodesis may provide another option to consider for reconstruction of SL instability.

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.

New NCAA Bat Standard, BBCOR, is Associated with an Increased Incidence of Hamate Fractures.

Our institution saw four hamate fractures in the 2011 baseball season, the first season following implementation of new batting standards in collegiate baseball. The purpose of this paper was to identify whether the incidence of hamate fractures increased with the introduction of the new batting standard. Surveys sent to Division 1 collegiate baseball athletic trainers reported the number, mechanism, treatment and return to play of hamate fractures from 2008-2010 (old batting standards) and for the 2011 season. This study shows that there was more than a 200% increased risk of hamate fracture with implementation of the 2011 collegiate baseball batting standards. The most common injury mechanism was batting with the down hand (79%). We suggest that a national injury database be considered for collegiate athletics so that injury rates, risk factors and results of interventions could be studied to improve the health of our nations' athletes. (Journal of Surgical Orthopaedic Advances 28(4):285-289, 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.

Impact of Design on Force between Flexor Tendons and Distal Radius Volar Plates.

Background Flexor tendon injury is a rare but serious complication of distal radius volar plating. Purpose This study aims to determine whether the design of distal radius volar plates impacts the amount of force exerted on the flexor digitorum profundus (FDP) and flexor pollicis longus (FPL) tendons when the plates are placed proximal and distal to the watershed line. Methods Three commercially available plates were applied to 10 fresh, matched-pair upper extremity specimens. Cyclical loading was applied to the tendons, and the force generated between tendon and plate was measured. Linear mixed effect models were used to evaluate differences in maximum and mean forces by plate position, plate design, and the interaction between position and design. Results Forces on the tendons differed significantly by position but not plate design. For the FPL tendon, the average maximum force with a plate in Soong's grade 2 was 4.50 (95% confidence interval [CI]: 2.8-7.3) times higher than when the plate was in a Soong's grade 0 placement, and 4.63 (95% CI: 2.82-7.61) times higher for the FDP tendon. While not statistically significant, lower observed force values with thinner plates when plates were placed distal to the watershed line suggest that that plate thickness could also be a critical plate characteristic for distally placed plates. Conclusion Despite differences in plate design, the main determinant of plate prominence and therefore flexor tendon injury potential is placement in relation to the watershed line. Clinical Relevance This study may help to guide surgeon implant selection and volar plate design.

Spontaneous Radial Nerve Palsy due to an Unrecognized Myofibroma: A Case Report.

CASE: A 33-year-old woman presented with a six-month history of spontaneous radial nerve palsy and no identified lesion on imaging. She underwent operative exploration where an hourglass deformity was seen and resected. Pathology returned as a rare tumor, a myofibroma. The patient regained full radial nerve function. CONCLUSIONS: A trial of observation is often indicated in the cases of isolated nerve palsy where anatomic lesions have been eliminated. This case highlights that imaging studies can miss a tumor involving nerve and that painless, spontaneous nerve palsy may be a time where early surgical intervention offers a better chance of recovery.

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.

The Effect of Radioscapholunate Fusion With and Without Distal Scaphoid and Triquetrum Excision on Capitolunate Contact Pressures.

PURPOSE: To determine the effects of motion-increasing modifications to radioscapholunate (RSL) arthrodesis on capitolunate contact pressure in cadaveric wrist specimens. METHODS: Ten fresh-frozen cadaveric wrists were dissected of all superficial soft tissue, potted in polymethyl-methacrylate, and the carpus exposed via a ligament-sparing capsulotomy. An RSL arthrodesis was simulated using 2 2.4-mm distal radius plates with locking screws. The distal scaphoid pole and triquetrum were removed with an osteotome and rongeur, respectively. Contact area, pressure, and force were measured in the capitolunate joint during the application of a 35-N uniaxial load using pressure-sensitive film. Measurements were obtained before and after simulated RSL fusion, following distal scaphoidectomy and after triquetrectomy. RESULTS: The combination of RSL fusion with distal scaphoid excision (DSE) increased contact forces in the capitolunate joint by 50% over controls. An RSL fusion, and RSL fusion with DSE and triquetrum excision (TE), exhibited intermediate levels of contact force between controls and RSL fusion with DSE. Capitolunate contact pressures were similar between all experimental groups. Contact area in the capitolunate joint increased by 43% after RSL fusion with DSE over intact specimen controls. Lastly, contact area in wrists with RSL fusion, and RSL fusion with DSE and TE, were elevated, but not significantly different from intact controls. CONCLUSIONS: A DSE performed at the time of RSL fusion results in increased midcarpal joint contact force and area, with resultant contact pressures unchanged. Triquetrectomy, which has been previously shown to improve range of motion, did not increase contact forces in the capitolunate joint. CLINICAL RELEVANCE: If a surgeon is contemplating performing an RSL arthrodesis with DSE, we recommend adding a triquetrectomy to improve motion because this does not add to the potentially deleterious effects of increased midcarpal contact force.