Lift-Off Screw Results in Accurate Sagittal Tilt Correction in a Distal Radius Fracture Model.

PURPOSE: To determine the accuracy of a distal-first open reduction internal plate fixation technique in achieving correction of volar tilt in dorsally angulated distal radius fractures. METHODS: Twenty foam radius models were divided evenly into groups N (normal) and O (osteoporotic). Dorsally angulated extra-articular distal radius fractures were then created. Group O underwent further modification to simulate an osteoporotic model. After static pinning in various degrees of dorsal angulation, opaque fiducial markers were placed and fluoroscopy was used to measure prereduction volar tilt. A variation of the distal-first plate application technique was used where a lift-off screw (LOS) was placed in the proximal most locking hole and propped the proximal aspect of the plate by the screw's length. The LOS length corresponded to the volar tilt correction needed. After fracture reduction using this technique, we measured the volar tilt again. We then compared the actual volar tilt correction with what was predicted based on the LOS length used. We also compared the tilt correction accuracy in the normal and osteoporotic models. RESULTS: Prereduction tilt ranged from 3° to 52° of dorsal tilt from normal (10° volar tilt). Corresponding LOSs ranged from 5 to 42 mm in length. Tilt correction correlated with screw length in a linear fashion (R = 0.9). The mean difference between actual and predicted tilt correction for a given screw length was 0.5° ± 3.0°, and the mean absolute difference was 2.4° ± 1.7° for all specimens. There was no difference between normal and osteoporotic models. CONCLUSIONS: Prereduction dorsal tilt can be accurately corrected within a few degrees of the goal by using the distal-first technique with an LOS. The LOS length can be calculated, and this technique can potentially be used with any distal radius periarticular locking plate with locking options in the shaft. CLINICAL RELEVANCE: A technique that provides accurate tilt correction would be of benefit to surgeons treating distal radius fractures with volar plates.

Long-term durability and functional outcomes among patients with artificial urinary sphincters: a 10-year retrospective review from the University of Michigan.

PURPOSE: The artificial urinary sphincter continues to be one of the most effective and commonly used surgical treatments for severe urinary incontinence. The long-term durability and functional outcome remains unclear. This study sought to report the artificial urinary sphincter complication rates, associated risk factors with complications, and long-term quality of life and durability. MATERIALS AND METHODS: This single institution study reports the outcomes of 124 consecutive index cases of artificial urinary sphincter from 1996 to 2006 for complications (infection, erosion, and mechanical failure). Bivariate statistics and multivariable logistic models were used to identify patient and artificial urinary sphincter characteristics associated with complications. Functional outcomes and long-term durability were assessed using a cross sectional analysis of a validated health related quality of life survey and a product limit estimates, respectively. RESULTS: Among the 124 male patients median followup was 6.8 years. The overall complication rate for patients undergoing an artificial urinary sphincter was 37.0%, with mechanical failure the most common cause (29), followed by erosion (10) and then infection (7). Significant differences between complications and specific patient and artificial urinary sphincter characteristics risk factors were not found. Functional outcomes appeared stable with similar mild-moderate urinary incontinence severity and 0 to 1 daily pad use at intervals of 0 to 4 years, 4 to 8 years and more than 8 years. Long-term durability was notable with 36% having complications (requiring surgical revision or removal) within 10 years and most events occurring within the first 48 months. CONCLUSIONS: Long-term durability and functional outcomes are achievable for the AMS 800, but there are appreciable complication rates for erosion, mechanical failure and infection in the first 48 months from implantation.

En1 and Wnt7a interact with Dkk1 during limb development in the mouse.

Wnt signaling plays an essential role in induction and development of the limb. Missing digits are one consequence of the reduced Wnt signaling in Wnt7a null mice, while extra digits result from excess Wnt signaling in mice null for the Wnt antagonist Dkk1. The extra digits and expanded apical ectodermal ridge (AER) of Dkk1-deficient mice closely resemble En1 null mice. To evaluate the in vivo interaction between En1 and the canonical Wnt signaling pathway, we generated double and triple mutants combining the hypomorphic doubleridge allele of Dkk1 with null alleles of En1 and Wnt7a. Reducing Dkk1 expression in Dkk1d/+Wnt7a-/- double mutants prevented digit loss, indicating that Wnt7a acts through the canonical pathway during limb development. Reducing Dkk1 levels in Dkk1d/dEn1-/- double mutants resulted in severe phenotypes not seen in either single mutant, including fused bones in the autopod, extensive defects of the zeugopod, and loss of the ischial bone. The subsequent elimination of Wnt7a in Dkk1d/dEn1-/-Wnt7a-/- triple mutants resulted in correction of most, but not all, of these defects. The failure of Wnt7a inactivation to completely correct the limb defects of Dkk1d/dEn1-/- double mutants indicates that Wnt7a is not the only gene regulated by En1 during development of the mouse limb.