Bony Anatomy around the Watershed Line of the Distal Radius

Background An important surgical landmark in the distal radius is the watershed line. The watershed line is a landmark for the positioning of volar locking plates (VLP) in the distal radius. Inconsistencies remain in the literature as to the presence and dimensions of landmarks in this compact area. We studied the detailed anatomy and dimensions of the distal radius with reference to bony anatomy around the watershed line, with special attention to the area between the pronator quadratus (PQ) and radial styloid. Materials and Methods The distal radius regions of 31 cadavers (23 right sided and 8 left sided) were dissected and studied. The heights at the junction of the scaphoid and lunate fossa, at the radial styloid, at the midpoint in between, and the widths of the PQ line, scaphoid, and lunate fossa were measured. The angle subtended by the pronator fossa and the radial styloid was also recorded. Results The mean heights at the junction of the scaphoid and lunate fossa, radial styloid, and midpoint in between were 5.1, 15.7, and 8.2 mm, respectively. The widths of the PQ line, scaphoid, and lunate fossa were 27, 19.4, and 10.6 mm, respectively. The mean angulation between the pronator fossa and the radial styloid was 128.9 degrees. Conclusion The area between the PQ and watershed line comprises a narrow area of bone which tapers to a point at its medial extent largely below the lunate fossa, thus it can hardly contain any implant proximal to the lunate fossa. The anterior orientation of this area and the concave anatomy of the articular surface mean careful screw direction is imperative to avoid inadvertent joint penetration. An angulation exists between the pronator fossa and the radial styloid, below the scaphoid fossa.

Volar Radiocarpal Ligament Repair with Suture Anchors for Radiocarpal Fracture Dislocations: Case Series

Background Radiocarpal fracture dislocations cause significant intraarticular disruption and instability difficult to treat with traditional plating methods. Description of Technique Suture anchor fixation of the volar radiocarpal ligaments through an extended carpal tunnel approach, supplemented with radial styloid fixation, restores stability to the radiocarpal joint. Patients and Methods We performed a retrospective review of 14 consecutive radiocarpal fracture-dislocations (RCFDs) treated at two-level one trauma center from 2011 to 2015. In all cases, the volar radiocarpal ligaments were repaired to the distal radius with suture anchors. Results We reviewed 14 Dumontier Group 2 RCFDs in 14 patients (10 males, four females) with an average age of 39 years (range 22–53 years). Final follow-up averaged 288 days (range 7–1,364 days). Surgeons performed volar ligament repair with suture anchors in all cases, radial styloid fixation in 79% (11/14), and dorsal plate fixation in 29% (4/14). Eight of 14 patients (57%) had a “flipped” volar lip fragment of the distal radius. Three patients had forearm compartment syndrome and two patients had acute carpal tunnel syndrome. No patients experienced radiocarpal subluxation after volar ligament repair. Conclusion No recurrent subluxation or dislocation occurred after primary repair of the volar radiocarpal ligaments using suture anchors in this series of radiocarpal fracture dislocations. Volar radiocarpal ligament repair also addressed the “flipped” volar rim fragment that could not be addressed through a dorsal approach alone. Level of Evidence: This is a Level IV, case series therapeutic study.

The Lateral Antebrachial Neurocutaneous Flap: A Cadaveric Study and Clinical Applications

Background The neurocutaneous flap is an axial pattern flap that receives a vascular supply from a vessel along its cutaneous nerve and has favorable outcomes when used for soft tissue reconstruction in the upper extremities. The neurocutaneous flap depends on the lateral antebrachial cutaneous nerve (LACN) and its retrograde-flow has been studied via cadaveric dissection. The aim of this study is to prove the vascularity of the lateral antebrachial neurocutaneous (LABN) flap. Methods The distally based LABN flap was created in 18 upper limbs (12 cadavers). The skin flap was dissected at the proximal half of the forearm and then diluted methylene blue was injected through the brachial artery. The pedicle of the flap on the distal half of the forearm was dissected along the LACN for the anatomical study of the perforating branches, paraneural vessels, and flap territory. Results The mean age of cadavers was 74.1 years (nine males). The mean distance of most distal and proximal perforating branches from the radial styloid process were 2.32 ± 0.59 and 11.17 ± 1.72 cm, respectively. The mean total number of perforating branches was 7.4, which abundantly appeared approximately 4 to 5 cm from the radial styloid process. The mean flap territory was 8.64 ± 0.82 cm in width and 10.50 ± 1.90 cm in length. The mean forearm circumference was 24.84 ± 1.52 cm, and mean forearm length was 24.74 ± 1.8 cm. Conclusion This study ensured that retrograde-flow via the neurocutaneous artery could be provided through the vascularity of the LABN flap, which suggests that the pivot point of the flap should not extend beyond 5 cm proximal to the radial styloid process. The LABN flap is a useful alternative method for performing soft tissue reconstruction in hand and wrist defects without sacrificing the major vessels.

Imaging appearance of post-arthroscopic radiocarpal chondrolysis: comparison with osteoarthritis associated with scapholunate dissociation

Background Since the diagnosis of post-arthroscopic chondrolysis is very difficult, it can be underdiagnosed and confused with other diseases in clinical practice. Purpose To propose imaging features of post-arthroscopic radiocarpal chondrolysis (PRCC) and to compare these with osteoarthritis associated with scapholunate dissociation which are the most common misdiagnoses of PRCC. Material and Methods To identify missed diagnoses of PRCC, 994 magnetic resonance imaging scans performed in 910 patients were retrospectively reviewed. After the identification of 73 patients who exhibited significant radiocarpal cartilage loss, 11 were diagnosed with PRCC. Since scapholunate advanced collapse was the most common incorrect diagnosis of PRCC (4/11), the imaging findings were compared among the 11 patients with PRCC and 14 patients with osteoarthritis caused by scapholunate dissociation who were diagnosed in the same period. The following imaging features were evaluated: scapholunate dissociation; the center of disease and grade of radiocarpal joint destruction; characteristics of bone marrow edema; the presence of radial styloid and distal scaphoid osteophytes; and the extent of joint effusion and synovitis. Results The imaging diagnosis of PRCC was significantly differentiated from osteoarthritis associated with scapholunate dissociation based on occurrence at a younger age, bone marrow edema crossing the joint, center of disease in the proximal radioscaphoid joint, and absence of radial styloid and scaphoid osteophytes ( P < 0.05). PRCC occasionally presented with arch-shape bone marrow edema based on the proximal carpal row. Conclusion The diagnosis of PRCC can be aided if its characteristic imaging findings are differentiated from other disease entities in patients with a history of arthroscopy.

Dorsal Barton fracture is a variation of dorsal radiocarpal dislocation: a clinical study

Dorsal Barton fractures may be better described as variants of dorsal radiocarpal dislocations. We aimed to better characterize these fractures by reviewing 111 patients in the ICUC® dataset who had a dorsally displaced, intra-articular distal radius fracture. We identified 13 patients with a dorsal Barton fracture on radiographs (dorsal articular margin fracture with radiocarpal subluxation and intact volar cortex). All patients with a dorsal Barton fracture had radial styloid involvement and volar cortical disruption that was subsequently identified on three-dimensional CT. Based on three-dimensional CT and intra-operative findings, none of the patients had classically described dorsal Barton fractures. All patients were treated using a volar exposure. A volar capsular tear was identified intra-operatively in three patients and the volar capsule repaired. This series supports the contention that dorsal Barton fractures are better characterized and treated as a variation of a dorsal radiocarpal dislocation. Level of evidence: IV

Magnesium Bioabsorbable Screw Fixation of Radial Styloid Fractures: Case Report

Background Several types of fixation materials may be used for the radial styloid fractures such as Kirschner wire fixation, screw fixation, volar plate fixation, and fragment-specific radial buttress plate fixation. However, each of these fixation techniques has certain complications usually related to either the surgical dissection or the application of fixation and symptomatic permanent hardware. Implant removal secondary to irritation of prominent screw heads or bulky plates is not uncommon after radial styloid fracture fixation. Case Description Herein, two patients with an isolated radial styloid fracture who were treated with bioabsorbable magnesium (alloy: MgYREZr) screws are presented. In both patients, the fracture union was achieved without any complication and need for implant removal. Literature Review This is the first report on the use of magnesium screws for this indication. Clinical Relevance Magnesium bioabsorbable compression screw fixation may be an alternative solution that eliminates removal operations due to symptomatic hardware in radial styloid fractures.

Dispelling the Myth of Work-Related de Quervain's Tenosynovitis

De Quervain’s Tenosynovitis (DQT) is a common condition characterized by pain about the dorsal-radial aspect of the wrist, just proximal to the radial styloid. The condition is precipitated by a thickened first dorsal compartment and its tendons. The impression that DQT is caused from work-related injury is misdirected, as no study has established an association between hand usage at work or trauma with DQT. Physicians should exercise caution when discussing the causes and natural history of DQT with symptomatic patients.