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.

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.

Clinical outcomes of limited-open retrograde intramedullary headless screw fixation of metacarpal fractures.

PURPOSE: To evaluate clinical and radiographic outcomes in patients treated with limited-open retrograde intramedullary headless compression screw (IMHS) fixation for metacarpal neck and shaft fractures. METHODS: Retrospective review of prospectively collected data on a consecutive series of 39 patients (34 men; 5 women), mean age 28 years (range, 16-66 y) treated with IMHS fixation for acute displaced metacarpal neck/subcapital (N = 26) and shaft (N = 13) fractures at a single academic practice between 2010 and 2014. Preoperative magnitude of metacarpal neck angulation averaged 54° (range, 15° to 70°), and shaft angulation averaged 38° (range, 0° to 55°). Patients used a hand-based orthosis until suture removal and began active motion within the first week. Clinical outcomes were assessed with digital goniometry, pad-to-distal palmar crease distance, and grip strength. Time to union and radiographic arthrosis was assessed. Twenty patients reached minimum 3-month follow-up, with a mean of 13 months (range, 3-33 mo). RESULTS: All 20 patients with minimum 3 months of follow-up achieved full composite flexion, and extensor lag resolved by 3-week follow-up. All patients demonstrated full active metacarpophalangeal joint extension or hyperextension. Grip strength measured 105% (range, 58% to 230%) of the contralateral hand. No secondary surgeries were performed. There were 2 cases of shaft re-fracture from blunt trauma following prior evidence of full osseous union with the screw in place. All patients achieved radiographic union by 6 weeks. There was no radiographic arthrosis at latest follow-up. One patient reported occasional clicking with metacarpophalangeal joint motion not requiring further treatment. CONCLUSIONS: Limited open retrograde IMHS fixation proved to be safe and reliable for metacarpal neck/subcapital and axially stable shaft fractures, allowed for early postoperative motion without affecting union rates, and obviated immobilization. This technique offers distinct advantages in select patients. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Predictable preparation, staining, and cementation procedures for chairside CAD/CAM dentistry.

Although direct composite resin procedures yield acceptable results when used correctly, if a large quantity of resin is required, complications may arise. In such cases, an indirect protocol must be followed. Numerous CAD/CAM systems, both laboratory and chairside, are available for practitioner use. In a laboratory system, a traditional impression is made and sent to a dental laboratory, where the restoration is fabricated. A chairside system, however, utilizes a digital impression system, and the restoration can then be milled and cemented in a single visit.

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.

Intrinsic fluorescence and redox changes associated with apoptosis of primary human epithelial cells.

Apoptosis plays a key role in the development and maintenance of human tissues. This process has been studied traditionally in cells that are stained with exogenous fluorophores. These approaches affect cell viability, and thus are ill-suited for in vivo applications. We present an imaging approach that can identify apoptotic cells in living cell populations based on detection and quantification of distinct changes in the intensity and localization of cellular autofluorescence. Specifically, we acquire NAD(P)H, FAD, and redox ratio autofluorescence images of primary keratinocytes following 1, 9, 14, and 18 h of treatment with cisplatin, a known apoptosis-inducing chemotherapy agent. We find that intense autofluorescence combined with a low redox fluorescence ratio is progressively confined to a gradually smaller perinuclear cytoplasmic region with cisplatin treatment. Studies with exogenous nuclear fluorophores demonstrate that these autofluorescence changes occur at early stages of apoptosis. Additional costaining experiments suggest that this strongly autofluorescent, highly metabolically active perinuclear ring represents a subpopulation of mitochondria that are mobilized in response to the apoptotic stimulus and may provide the energy required to execute the final apoptotic steps. Thus, autofluorescence localization changes could serve as a sensitive, noninvasive indicator of early apoptosis in vivo.

Diagnosis, Treatment, and Return to Play for Four Common Sports Injuries of the Hand and Wrist.

Hand and wrist injuries in the high-level athlete are challenging because they may be underestimated by the patient, family, and team, and return to play may be longer than desired. The needs of the player and the team must be balanced with the long-term functional ramifications of the injury. Four common soft-tissue sports injuries are flexor digitorum profundus avulsion, flexor pulley rupture, extensor carpi ulnaris dislocation, and thumb metacarpophalangeal joint ulnar collateral ligament injury. For each of these injuries, the assessment, treatment, and considerations for return to play should be individualized on the basis of the patient, the sport, and the timing of the injury.

Techniques used to fabricate all-ceramic restorations in the dental practice.

Porcelain is an increasingly popular material to use for restorations. This article will discuss the 3 main ways to fabricate porcelain restorations. The first method involves waxing up the restoration to the proper form and casting it in molten porcelain similar to the lost wax technique for gold. The second technique requires the use of porcelain in a powder form to be stacked on top of a refractory die or a platinum foil and then fired in the oven. The third main technique is the use of a CAD/CAM system to mill the porcelain restoration from a solid block of porcelain. All 3 techniques are valid and the clinician should have a thorough understanding of which techniques are appropriate in various clinical situations.