Quantitative Analysis of the Volar Ulnar Corner of the Distal Radius: A Reference for Intraoperative Distal Radius Fracture Reduction.

PURPOSE: The reduction of distal radius fractures using volar locking plate fixation can be performed by securing the plate to the distal fragments and then levering the plate to the radial shaft. Oblique placement of the plate on the radial shaft may lead to malreduction. The aim of this study was to evaluate parameters that can be used for the assessment of intraoperative distal radius fracture reduction using "distal-first" volar plate fixation, especially the geometry of the ulnar corner. The prevalence of Tolat distal radioulnar joint (DRUJ) types was determined, and the angles of the volar corner were quantitatively described. METHODS: Three hundred seventy-five adult patients with a conventional wrist radiograph in their medical chart were identified. From this cohort, 50 radiographs of each Tolat DRUJ type were quantitatively analyzed using 4 angles. The probability density of each angle was described using Kernel density estimation graphs. A multivariable analysis was used to study the association between the 4 angles and Tolat DRUJ types and other patient factors. RESULTS: One hundred fifty-one patients (40%) had a wrist with type 1 DRUJ, 147 (39%) had a wrist with type 2 DRUJ, and 77 (21%) had a wrist with type 3 DRUJ. The measurements of the distal ulnar corner, volar ulnar corner, and DRUJ angulation were significantly different among each Tolat DRUJ type. The median lunate facet inclination, relative to the axis of the radial shaft, measured 14° (interquartile range, 12°-16°) across all the Tolat DRUJ types. CONCLUSIONS: The prevalence of Tolat type 1, 2, and 3 DRUJ was 40%, 39%, and 21%, respectively. The angles of the volar ulnar corner varied with each DRUJ type. CLINICAL RELEVANCE: Because the lunate facet inclination was relatively consistent among all the Tolat DRUJ types, this angle may be useful as a reference for "distal-first" distal radius volar plating.

Bone density measurements from CT scans may predict the healing capacity of scaphoid waist fractures.

AIMS: We quantitatively compared the 3D bone density distributions on CT scans performed on scaphoid waist fractures subacutely that went on to union or nonunion, and assessed whether 2D CT evaluations correlate with 3D bone density evaluations. METHODS: We constructed 3D models from 17 scaphoid waist fracture CTs performed between four to 18 weeks after fracture that did not unite (nonunion group), 17 age-matched scaphoid waist fracture CTs that healed (union group), and 17 age-matched control CTs without injury (control group). We measured the 3D bone density for the distal and proximal fragments relative to the triquetrum bone density and compared findings among the three groups. We then performed bone density measurements using 2D CT and evaluated the correlation with 3D bone densities. We identified the optimal cutoff with diagnostic values of the 2D method to predict nonunion with receiver operating characteristic (ROC) curves. RESULTS: In the nonunion group, both the distal (100.2%) and proximal (126.6%) fragments had a significantly higher bone density compared to the union (distal: 85.7%; proximal: 108.3%) or control groups (distal: 91.6%; proximal: 109.1%) using the 3D bone density measurement, which were statistically significant for all comparisons. 2D measurements were highly correlated to 3D bone density measurements (Spearman's correlation coefficient (R) = 0.85 to 0.95). Using 2D measurements, ROC curve analysis revealed the optimal cutoffs of 90.8% and 116.3% for distal and proximal fragments. This led to a sensitivity of 1.00 if either cutoff is met and a specificity of 0.82 when both cutoffs are met. CONCLUSION: Using 3D modelling software, nonunions were found to exhibit bone density increases in both the distal and proximal fragments in CTs performed between four to 18 weeks after fracture during the course of treatment. 2D bone density measurements using standard CT scans correlate well with 3D models. In patients with scaphoid fractures, CT bone density measurements may be useful in predicting the likelihood of nonunion. Cite this article: Bone Joint J 2020;102-B(9):1200-1209.

A Single Incision Anterior Approach for Transhumeral Amputation Targeted Muscle Reinnervation.

Targeted muscle reinnervation (TMR) is an evolving technique with promising results for prevention and treatment of neuropathic pain, as well as modulation of control for myoelectric prostheses. The previously described and most commonly used technique for transhumeral TMR combines both an anterior and posterior approach to access the major peripheral nerves of the upper extremity. In this article, we review the literature for transhumeral TMR and describe a more expeditious and efficient anterior-only approach that offers safe access through a single incision.

Management of High Energy Distal Radius Injuries.

PURPOSE OF REVIEW: High energy distal radius are commonly multi-fragmentary with significant comminution and/or bone loss. They can also be associated with ligamentous and soft tissue injury and neurovascular compromise. As such, reconstruction of these injuries can be challenging. This paper will review the relevant anatomy, different methods of fixation, and present techniques for difficult fractures. RECENT FINDINGS: Volar locked plating is a successful, very common method of treatment for distal radius fractures, but dorsal plating, fragment specific fixation, spanning bridge plating, and external fixation are sometimes necessary, particularly in higher energy injuries characterized by metaphyseal comminution, small volar fragments, intra-articular free fragments or lunate facet subsidence. Extended flexor carpi radialis (FCR), dorsal, and flexor carpi ulnaris (FCU) exposures can assist in visualizing the fracture site. There are many different modes of fixation for distal radius fractures, and successful outcome depends on selection of appropriate fixation based on the fracture pattern and status of the soft tissues.