Role of high-resolution peripheral nerve magnetic resonance imaging in diagnosing median nerve tethering in a case of both-bone forearm fracture in a child.

Forearm fractures are common injuries in pediatric patients. We present a case of median nerve tethering as a complication of both-bone forearm fracture in a child, with an emphasis on MRI as an appropriate and important complement to clinical and electrodiagnostic examination. Early intervention is essential because delayed surgical management of median nerve tethering can result in poor clinical outcomes as a result of irreversible muscle denervation. In this case, we highlight the importance of MRI to facilitate management, including early surgical intervention when appropriate, in median neuropathy following forearm fractures.

Managing the Athlete with a Scaphoid Fracture.

Most minimally displaced scaphoid fractures and all displaced scaphoid fractures in elite athletes are treated with early fixation to maximally expedite the return to full function. Computed tomographic (CT) scans are recommended in all scaphoid fractures to facilitate a complete understanding of fracture anatomy and to allow for optimal screw placement. Screw placement is important to maximize healing capacity of the fracture and allow for return to sport. Postoperative CT scans can be helpful to evaluate the extent of healing and may allow patients to return to play sooner.

The Use of Three-Dimensional Printing for Complex Scaphoid Fractures.

Scaphoid fractures are one of the most common fractures treated by hand surgeons. The complex anatomy and size of the scaphoid bone can make the reduction and fixation of these fractures technically challenging. Careful preoperative planning is required to ensure stable fixation is achieved. We report on the use of 3-dimensional printing to improve preoperative planning for a series of complex scaphoid fractures.

Micro Screw Fixation for Small Proximal Pole Scaphoid Fractures with Distal Radius Bone Graft.

Background Achieving adequate fixation and healing of small proximal pole acute scaphoid fractures can be surgically challenging due to both fragment size and tenuous vascularity. Purpose The purpose of this study was to demonstrate that this injury can be managed successfully with osteosynthesis using a "micro" small diameter compression screw with distal radius bone graft with leading and trailing screw threads less than 2.8 mm. Patients and Methods Patients with proximal pole scaphoid fragments comprising less than 20% of the entire scaphoid were included. Fixation was accomplished from a dorsal approach with a micro headless compression screw and distal radius bone graft. Six patients were included. Average follow-up was 44 months (range, 11-92). Results Mean proximal pole fragment size was 14% (range, 9-18%) of the entire scaphoid. The mean immobilization time was 6 weeks, time-to-union of 6 weeks, and final flexion/extension arc of 88°/87°. All patients had a successful union, and no patient had deterioration in range of motion, avascular necrosis, or fragmentation of the proximal pole. Conclusion Small diameter screws with a maximal thread diameter of ≤ 2.8 mm can be used to fix the union of proximal pole acute scaphoid fractures comprising less than 20% of the total area with good success. Level of Evidence Therapeutic case series, Level IV.

Cadaveric Testing of a Novel Scapholunate Ligament Reconstruction.

Background Existing scapholunate interosseous ligament (SLIL) reconstruction techniques include fixation spanning the radiocarpal joint, which do not reduce the volar aspect of the scapholunate interval and may limit wrist motion. Questions/Purpose This study tested the ability of an SLIL reconstruction technique that approximates both the volar and dorsal scapholunate intervals, without spanning the radiocarpal joint, to restore static scapholunate relationships. Materials and Methods Scapholunate interval, scapholunate angle, and radiolunate angle were measured in nine human cadaveric specimens with the SLIL intact, sectioned, and reconstructed. Fluoroscopic images were obtained in six wrist positions. The reconstruction was performed by passing tendon graft through bone tunnels from the dorsal surface toward the volar corner of the interosseous surface. After reduction of the scapholunate articulation, the graft was tensioned within the lunate bone tunnel, secured with an interference screw in the scaphoid, and sutured to the dorsal SLIL remnant. Differences among testing states were evaluated using repeated measures ANOVA. Results There was a significant increase in the scapholunate interval in all wrist positions after complete SLIL disruption. Compared with the disrupted state, there was a significant decrease in scapholunate interval in all wrist positions after reconstruction using a tendon graft and interference screw. Conclusion Our SLIL reconstruction technique reconstructs the volar and dorsal ligaments of the scapholunate joint and adequately restores static measures of scapholunate stability. This technique does not tether the radiocarpal joint and aims to optimize volar reduction. Clinical Relevance Our technique offers an alternative option for SLIL reconstruction that successfully restores static scapholunate relationships.

Importance of Computed Tomography in Determining Displacement in Scaphoid Fractures.

Background Displaced scaphoid fractures have a relatively high rate of nonunion. Detection of displacement is vital in limiting the risk of nonunion when treating scaphoid fractures. Questions/Purpose We evaluated the ability to diagnose displacement on radiographs and computed tomography (CT), hypothesizing that displacement is underestimated in assessing scaphoid fracture by radiograph compared with CT. Materials and Methods Thirty-five preoperative radiographs and CT scans of acute scaphoid fractures were evaluated by two blinded observers. Displacement and angular deformity were measured, and the fracture was judged as displaced or nondisplaced. Scapholunate, radiolunate, and intrascaphoid angles were measured. Radiograph and CT measurements between nondisplaced and displaced fractures were compared. Intraobserver reliability was measured. Results Reader 1 identified 12 fractures as nondisplaced on radiograph, but displaced on CT (34%). Reader 2 identified 9 fractures as nondisplaced on radiograph, but displaced on CT (26%). For displaced fractures, the mean intrascaphoid angle was over three times greater when measured on CT than on radiograph (56 vs. 16 degrees). Scapholunate angle >65 degrees and radiolunate angle >16 degrees were significantly associated with displacement on CT. Interobserver reliability for diagnosing displacement was perfect on CT but less reliable on radiograph. Conclusion Scaphoid fracture displacement on CT was identified in 26 to 34% of fractures that were nondisplaced on radiograph, confirming that radiographic evaluation alone underestimates displacement. These results underscore the importance of CT scan in determining displacement and angular deformity when evaluating scaphoid fractures, as it may alter the decision on treatment and surgical approach to the fracture. We recommend considering CT scan to evaluate all scaphoid fractures. Level of Evidence Level III.

Variable Bone Density of Scaphoid: Importance of Subchondral Screw Placement.

Background Ideal internal fixation of the scaphoid relies on adequate bone stock for screw purchase; so, knowledge of regional bone density of the scaphoid is crucial. Questions/Purpose The purpose of this study was to evaluate regional variations in scaphoid bone density. Materials and Methods Three-dimensional CT models of fractured scaphoids were created and sectioned into proximal/distal segments and then into quadrants (volar/dorsal/radial/ulnar). Concentric shells in the proximal and distal pole were constructed in 2-mm increments moving from exterior to interior. Bone density was measured in Hounsfield units (HU). Results Bone density of the distal scaphoid (453.2 ± 70.8 HU) was less than the proximal scaphoid (619.8 ± 124.2 HU). There was no difference in bone density between the four quadrants in either pole. In both the poles, the first subchondral shell was the densest. In both the proximal and distal poles, bone density decreased significantly in all three deeper shells. Conclusion The proximal scaphoid had a greater density than the distal scaphoid. Within the poles, there was no difference in bone density between the quadrants. The subchondral 2-mm shell had the greatest density. Bone density dropped off significantly between the first and second shell in both the proximal and distal scaphoids. Clinical Relevance In scaphoid fracture ORIF, optimal screw placement engages the subchondral 2-mm shell, especially in the distal pole, which has an overall lower bone density, and the second shell has only two-third the density of the first shell.

Dorsal Scaphoid Subluxation on Sagittal Magnetic Resonance Imaging as a Marker for Scapholunate Ligament Tear.

PURPOSE: To evaluate the diagnostic utility of scaphoid dorsal subluxation on magnetic resonance imaging (MRI) as a predictor of scapholunate interosseous ligament (SLIL) tears and compare this with radiographic findings. METHODS: Thirty-six MRIs were retrospectively reviewed: 18 with known operative findings of complete Geissler IV SLIL tears that were surgically repaired, and 18 MRIs performed for ulnar-sided wrist pain but no SLIL tear. Dorsal subluxation of the scaphoid was measured on the sagittal MRI cut, which demonstrated the maximum subluxation. Independent samples t tests were used to compare radiographic measurements of scapholunate (SL) gap, SL angle, and capitolunate/third metacarpal-lunate angles between the SLIL tear and the control groups and to compare radiographic measurements between wrists that had dorsal subluxation of the scaphoid and wrists that did not have dorsal subluxation. Interrater reliability of subluxation measurements on lateral radiographs and on MRI were calculated using kappa coefficients. RESULTS: Thirteen of 18 wrists with complete SLIL tears had greater than 10% dorsal subluxation of the scaphoid relative to the scaphoid facet. Average subluxation in this group was 34%. Four of 18 wrists with known SLIL tears had no subluxation. No wrists without SLIL tears (control group) had dorsal subluxation. The SL angle, capitolunate/third metacarpal-lunate angle and SL gap were greater in wrists that had dorsal subluxation of the scaphoid on MRI. Interrater reliability of measurements of dorsal subluxation of the scaphoid was superior on MRI than on lateral x-ray. CONCLUSIONS: An MRI demonstration of dorsal subluxation of the scaphoid, of as little as 10%, as a predictor of SLIL tear had a sensitivity of 72% and a specificity of 100%. The high positive predictive value indicates that the presence of dorsal subluxation accurately predicts SLIL tear. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic II.

A Biomechanical Comparison of Extensor Carpi Ulnaris Subsheath Reconstruction Techniques.

PURPOSE: Several surgical stabilization techniques have been described to address pathological subluxation of the extensor carpi ulnaris (ECU) tendon, with no comparative data available. This study compares ECU stability after subsheath reconstruction, with and without ulnar groove deepening, to stability with an intact subsheath in a cadaveric model. METHODS: Position of the ECU tendon relative to the ulnar groove was measured in 5 human cadaveric specimens with the subsheath intact, sectioned, and after 3 reconstruction scenarios: reconstructed, reconstructed with ulnar groove deepened, and ulnar groove deepened with subsheath sectioned. Position of the tendon relative to the radial side of the ulnar groove was recorded with digital calipers in 9 combinations of wrist/forearm positions (wrist flexion, extension, and neutral; forearm pronation, supination, and neutral). Dislocation events, defined as the tendon being completely ulnar to the groove, were recorded. RESULTS: Extensor carpi ulnaris tendon displacement was not significantly different between intact subsheath, subsheath reconstruction, and reconstruction with groove deepening (1.5 mm vs 0.5 mm vs -0.3). Extensor carpi ulnaris tendon displacement after groove deepening with the subsheath sectioned was not significantly different from displacement with a fully sectioned subsheath. Sectioning of the subsheath induced dislocation events of the ECU tendon in multiple positions. Subsheath reconstruction with and without groove deepening allowed no dislocation events. CONCLUSIONS: In this cadaveric model, groove deepening did not improve stability of the ECU tendon compared with the reconstructed subsheath, and reconstruction alone was equally effective at eliminating dislocation events. CLINICAL RELEVANCE: Stabilization techniques that focus on restoration of the important ulnar attachment of the ECU subsheath are favored over routine deepening of the ulnar groove in attempts to stabilize the ECU tendon.

Effect of Screw Perpendicularity on Compression in Scaphoid Waist Fractures.

Background Central and perpendicular (PERP) screw orientations have each been described for scaphoid fracture fixation. It is unclear, however, which orientation produces greater compression. Questions/Purposes This study compares compression in scaphoid waist fractures with screw fixation in both PERP and pole-to-pole (PTP) configurations. PERP orientation was hypothesized to produce greater compression than PTP orientation. Methods Ten preoperative computed tomography scans of scaphoid waist fractures were classified by fracture type and orientation in the coronal and sagittal planes. Three-dimensional models of each scaphoid and fracture plane were created. Simulated Acutrak 2 (Acumed, Hillsboro, OR) screws were placed into the models in both PERP and PTP orientations. Engagement length and screw angle relative to the fracture were measured. Compression strength was calculated from the shear area, average density, and angle acuity. Results The PTP angle between screw and fracture ranged from 36 to 84 degrees. By definition, the PERP screw-to-fracture angle was 90 degrees. Perpendicularity of the PTP screw to the fracture was positively correlated to compression strength. PERP screws had greater compression than PTP screws when the PTP screw-to-fracture angle was < 80 degrees (106 vs. 80 N), but there was no difference in compression when the PTP screw-to-fracture angle was > 80 degrees, approximating the PERP screw. Conclusion Increasing screw perpendicularity resulted in higher compression when the screw-to-fracture angle of the PTP screw was < 80 degrees. Maximum compression was obtained with a screw PERP to the fracture. The increased compression gained from PERP screw placement offsets the decreased engagement length. Clinical Relevance These results provide guidelines for optimal screw placement in scaphoid waist fractures.

Thumb collateral ligament injuries in the athlete.

PURPOSE OF REVIEW: The purpose of this review is to identify current principles in the diagnosis and treatment of collateral ligament injuries of the thumb in the athlete. RECENT FINDINGS: Cadaver studies have clearly identified the ulnar and radial collateral ligaments origin and insertion footprints for repair or reconstruction. Ulnar and radial collateral ligament injuries are common in athletics. History and physical examination are paramount in determining partial versus complete tear. When surgical treatment is indicated, placing the repair/reconstruction in the anatomic footprint restores stability while maintaining motion. The senior author's preferred techniques are reported.

Expediting Professional Athletes' Return to Competition.

Return-to-play (RTP) decisions often represent a challenge to physicians caring for athletes. The multifaceted and unique nature of each RTP decision makes standardization of the decision-making process impossible and demands of the physician thoughtful consideration of all competing interests and variables. Such difficult medical decisions are further complicated by unique ethical and legal considerations. Although no concrete RTP recommendations are available, the consensus of experienced team physicians and knowledge of the rules and regulations that apply to RTP are helpful guides to treating the various upper extremity injuries that occur in elite athletes.

Modified Sublimis Tenodesis: Surgical Technique for Treating Chronic Traumatic Proximal Interphalangeal Joint Hyperextension Instability.

Many surgical techniques for treating chronic posttraumatic hyperextension instability of the proximal interphalangeal (PIP) joint involve exploration of the PIP joint, often leading to stiffness in an already traumatized joint. This article outlines the indications, contraindications, surgical technique, and postoperative management for a modified flexor digitorum sublimis tenodesis that utilizes 2 small incisions, a slip of flexor digitorum sublimis, a suture anchor, and temporary pinning of the PIP joint, while avoiding violation of the PIP capsule.

Relative Contribution of the Subsheath to Extensor Carpi Ulnaris Tendon Stability: Implications for Surgical Reconstruction and Rehabilitation.

PURPOSE: To identify the varying contributions of the proximal and distal portions of the subsheath of the extensor carpi ulnaris (ECU) to its stability, evaluate the correlation of ulnar groove depth and ECU subluxation, and observe the effect of forearm and wrist positions on ECU stability. METHODS: Extensor carpi ulnaris tendon position relative to the ulnar groove was measured in 10 human cadaveric specimens with the subsheath intact, partially sectioned (randomized to distal or proximal half), and fully sectioned. Measurements were obtained in 9 positions: forearm supinated, neutral, and pronated and wrist extended, neutral, and flexed. Ulnar groove depth was measured on all specimens. RESULTS: In 7 of 10 specimens with an intact subsheath, the ECU tendon subluxated out of the groove in at least 1 forearm-wrist position. We noted the subluxation of the ECU tendon in all wrist-forearm positions with the exception of pronation-extension in at least 1 specimen. For partial subsheath sectioning, tendon displacement markedly increased after distal subsheath sectioning but not after proximal sectioning. For full subsheath sectioning, wrist flexion produced subluxation in all forearm positions, and forearm supination produced subluxation in all wrist positions. Maximum displacement occurred in supination-flexion. There was no correlation between ulnar groove depth and ECU subluxation. CONCLUSIONS: Mild tendon subluxation occurred in the intact specimens in most tested positions. Two positions were remarkable for their consistency in maintaining the tendon within the groove: pronation-neutral and pronation-extension. In fully sectioned specimens, the greatest subluxation occurred in supination-flexion, with supination and flexion independently producing subluxation. Partial sectioning demonstrated that the distal portion of the subsheath played a more important role than the proximal portion in stabilizing the ECU. CLINICAL RELEVANCE: Subsheath repair or reconstruction should target the distal portion of the subsheath. During postinjury rehabilitation or following surgical reconstruction, combined forearm supination and wrist flexion should be avoided.

Opportunistic Osteoporosis Screening - Gleaning Additional Information from Diagnostic Wrist CT Scans.

BACKGROUND: Although screening for and treating osteoporosis can prevent subsequent fractures, the rates of such interventions are low following a distal radial fracture. One potential method for identifying metabolic bone disease is via Hounsfield unit (HU) measurements from diagnostic computed tomography (CT) scans. We hypothesized that HU values of the distal aspect of the radius could be used to assess local bone quality and would be predictive of distal radial fracture risk, thereby allowing the identification of patients in need of further management. METHODS: Measurements of bone mineral density (BMD) were made for 100 patients on the basis of HU values of cancellous portions of the distal aspect of the radius, the ulnar head, and the capitate. The HU values in twenty-five male and twenty-five female patients with an acute distal radial fracture documented on CT were compared with those of age and sex-matched control patients who had a CT scan obtained for other indications. RESULTS: Among the control patients, HU values decreased as age increased. When assessed on the basis of sex, both male and female patients with a distal radial fracture had significantly lower regional BMD compared with nonfracture control patients. A distal radial HU value of 218 for females and 246 for males optimized sensitivity and specificity; values below this threshold were associated with an increased risk of distal radial fracture. CONCLUSIONS: HU measurements can be obtained from any diagnostic CT scan using modern software programs and can be obtained by physicians in the office setting with minimal effort and at no additional cost or radiation exposure to the patient. Regardless of imaging indications, we suggest that patients with HU values below the identified thresholds be considered for further metabolic bone disease work-up, such as additional imaging, laboratory assessments, the initiation of osteoporosis treatment, or appropriate referral.

Biomechanical Analysis of Scapholunate Ligament Repair Techniques.

PURPOSE: To evaluate the biomechanical properties of 3 scapholunate repair techniques. METHODS: In 51 cadavers, the scapholunate ligament was exposed through a dorsal approach, incised at its scaphoid insertion, and repaired using 1 of 3 techniques: 2 single-loaded suture anchors, 2 double-loaded suture anchors, or 2 transosseous sutures. Twenty-four repaired specimens underwent load to failure (LTF) testing using tensile distraction on a servo-hydraulic machine. Twenty-seven specimens underwent cyclical testing to measure gap formation at the scapholunate joint. RESULTS: The mode of failure was suture pullout through the substance of the ligament in 22 specimens, failure at the bone suture interface in 1, and anchor pullout in 1. Double-loaded anchor repairs demonstrated a significantly higher mean ultimate LTF compared with single-loaded anchor (91 N vs 35 N) and transosseous (91 N vs 60 N) repairs. Transosseous repairs demonstrated a higher mean ultimate LTF compared with single-loaded suture repairs (60 N vs 35 N). After 300 cycles, the average gap for the transosseous repair group was double that for the single- and double-loaded repairs, although not statistically significant. CONCLUSIONS: Primary scapholunate ligament repairs using double-loaded suture anchors demonstrated significantly higher strength compared with single-loaded anchors and transosseous repairs. On cyclic loading, transosseous repairs demonstrated the greatest gap formation with no measurable difference between single- and double-loaded repairs. CLINICAL RELEVANCE: In a cadaveric model for primary repairs, double-loaded suture anchors demonstrated the highest LTF and offer a similar but unproven performance in vivo.

Vascular anomalies of the hand and wrist.

Vascular malformations of the hand and wrist are uncommon. They develop from aberrations in angiogenic signaling during vascular development. Unlike hemangiomas, which are characterized by biphasic growth and slow spontaneous involution, vascular malformations continue to grow proportionally with the child. Management is dictated by classification of the vascular malformations, which is based on flow characteristics (ie, low, high) and predominant cell type (ie, venous, lymphatic, capillary, combined, arteriovenous). Initial management is conservative, with the goal of providing relief from pain and swelling. Sclerotherapy, laser treatment, and arterial embolization may be beneficial in well-selected patients. Surgery is indicated in cases of persistent pain and uncontrolled limb swelling leading to functional impairment and/or neurologic compression. The goals of surgery are to excise as much of the lesion as possible while avoiding injury to adjacent nerves, minimizing blood loss, and preventing distal limb ischemia. This mandates careful preoperative planning and meticulous technique. Adjuvant treatments may be warranted, as in the case of preoperative embolization in patients with high-flow lesions.

Management of nonunion following surgical management of scaphoid fractures: current concepts.

Management of scaphoid nonunion after failed surgery for acute scaphoid fracture presents a unique treatment challenge. Prior surgery complicates patient evaluation and increases the technical difficulty of future procedures. Healing of nonunion is crucial to prevent carpal collapse and progressive arthritis. A thorough workup is required to identify technical factors or treatment decisions that may have resulted in a poor outcome after initial fixation attempts. CT is particularly useful for characterizing nonunion and planning revision surgery. Several studies have described the use of bone grafts and fixation devices for scaphoid nonunion repair, including nonvascularized and vascularized bone grafts, screws, pins, and plates. Reliable rates of union have been achieved using nonvascularized bone graft supplemented with screw or wire fixation, particularly in the absence of osteonecrosis. Although vascularized grafts are more technically challenging, they improve the odds of union in the setting of osteonecrosis.

Volar plate position and flexor tendon rupture following distal radius fracture fixation.

PURPOSE: To determine whether there were differences between plate position in patients who had postoperative flexor tendon ruptures following volar plate fixation of distal radius fractures and those who did not. METHODS: Three blinded reviewers measured the volar plate prominence and position on the lateral radiographs of 8 patients treated for flexor tendon ruptures and 17 matched control patients without ruptures following distal radius fracture fixation. We graded plate prominence using the Soong grading system, and we measured the distances between the plate and both the volar critical line and the volar rim of the distal radius. RESULTS: A higher Soong grade was associated with flexor tendon rupture. Patients with ruptures had plates that were more prominent volarly and more distal than matched controls without ruptures. Plate prominence projecting greater than 2.0 mm volar to the critical line had a sensitivity of 0.88, a specificity of 0.82, and positive and negative predictive values of 0.70 and 0.93, respectively, for tendon ruptures. Plate position distal to 3.0 mm from the volar rim had a sensitivity of 0.88, a specificity of 0.94, and positive and negative predictive values of 0.88 and 0.94, respectively, for tendon ruptures. CONCLUSIONS: We identified plate positions associated with attritional flexor tendon rupture following distal radius fracture fixation with volar plates. To decrease rupture risk, we recommend considering elective hardware removal after union in symptomatic patients with plate prominence greater than 2.0 mm volar to the critical line or plate position within 3.0 mm of the volar rim. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III.