Pablo Wagner
Universidad del Desarrollo
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Pablo Wagner.
Foot & Ankle International | 2013
Emilio Wagner; Cristian Ortiz; Ignacio Villalon; Andres Keller; Pablo Wagner
Background: Anatomic restoration and postoperative rehabilitation of displaced fracture-dislocations of the tarsometatarsal junction of the foot are essential. Our objective was to report percutaneous reduction and screw fixation results in low-energy Lisfranc fracture dislocation injuries that were treated with early weight-bearing and rehabilitation. Methods: We retrospectively evaluated patients with low-energy Lisfranc injuries who underwent surgery between May 2007 and April 2011. The study reviewed 22 patients (12 men and 10 women) with an average age of 36.2 years (range, 16-50 years) and an average follow-up of 33.2 months (range, 12-50 months). We report the mechanism of trauma; quality of reduction in the postoperative digital radiographs; subjective satisfaction; AOFAS score; time required to return to work, recreational activities, and low-impact sports; and complications. Postoperatively, all of the patients were instructed to be non-weight-bearing for 3 weeks, and the stitches were removed after 2 weeks. At the third postoperative week, the patients were encouraged to bear weight as tolerated. Results: Quality of reduction was anatomic or near anatomic in 100% of cases. The subjective satisfaction reported by patients was very good, with complete satisfaction in 20 of them (90.9%). The AOFAS average was 94 points (range, 90-100 points). Average return to work was at 7 weeks (range, 6-9 weeks), recreational activities 7.2 weeks (range, 6-9 weeks), training for low-impact sports 7.6 weeks (range, 7-8 weeks), and symptom-free sport activities 12.4 weeks (range, 11-13 weeks). Conclusion: In this selected group of patients with low-energy Lisfranc fracture dislocation, anatomic or near-anatomic reduction can be achieved with percutaneous reduction and screw fixation. Early weight-bearing is possible in these patients, and early return to regular activities and low-impact sport can be expected. Level of Evidence: Level IV, retrospective case series.
Foot & Ankle International | 2013
Emilio Wagner; Cristian Ortiz; John S. Gould; Sameer Naranje; Pablo Wagner; Pablo Mococain; Andres Keller; Juan José Valderrama; Maximiliano Espinosa
Background: The proximal oblique sliding closing wedge osteotomy (POSCOW) technique was developed to address moderate to severe hallux valgus deformity. We present a retrospective multicenter study to analyze the midterm radiological and clinical outcomes of patients treated with this type of proximal osteotomy fixed with plates. Materials and Methods: One hundred and forty-four patients (187 feet) were operated on between May 2005 and June 2010 in 2 separate centers. Inclusion criteria were symptomatic moderate to severe incongruent hallux valgus deformity, no significant restriction in the first metatarsophalangeal joint movement, none to minimal degenerative changes in the first metatarsophalangeal or the tarsometatarsal joints, and no hypermobility. The median age was 60 years. The preoperative hallux valgus angle (HV) was 35.6 degrees, intermetatarsal angle (IM) was 15.3 degrees, AOFAS score was 53 points. The median follow-up was 35 months (range, 12-73). A POSCOW osteotomy was performed in all patients and fixed with plates. We recorded the satisfaction rate, postoperative clinical and radiological results, and complications. Results: The patient satisfaction rate was 87%. The mean postoperative HV angle was 12.3 degrees, IM angle 4.8 degrees, AOFAS score 89 points. The mean decrease in the first metatarsal length was 2.2 mm (range, 0-8). Twelve feet (6.4%) with recurrence of the deformity required revision surgeries. Removal of complete or partial hardware was needed in 23 feet (12.3%) for symptomatic hardware. Five feet (2.6%) developed hallux varus but only 2 required surgery. Transfer metatarsalgia was noted in 9 feet (4.8%). Conclusions: The POSCOW osteotomy was an effective and reliable method for relieving pain and improving function. A learning curve was present, as most of the complications happened in the initial cases. To our knowledge, this is the largest reported series of proximal closing wedge osteotomy for hallux valgus deformities. Level of Evidence: Level IV, case series.
Journal of Bone and Joint Surgery, American Volume | 2014
Emilio Wagner; Cristian Ortiz; Pablo Wagner; R. Guzman; Ximena Ahumada; Nicola Maffulli
BACKGROUND Side-to-side tenorrhaphy is increasingly used, but its mechanical performance has not been studied. METHODS Two porcine flexor digitorum tendon segments of equal length (8 cm) and thickness (1 cm) were placed side by side. Eight tenorrhaphies (involving sixteen tendons) were performed with each of four suture techniques (running locked, simple eight, vertical mattress, and pulley suture). The resulting constructs underwent cyclic loading on a tensile testing machine, followed by monotonically increasing tensile load if failure during cyclic loading did not occur. Clamps secured the tendons on each side of the repair, and specimens were mounted vertically. Cyclic loading varied between 15 N and 35 N, with a distension rate of 1 mm/sec. Cyclic loading strength was determined by applying a force of 70 N. The cause of failure and tendon distension during loading were recorded. RESULTS All failures occurred in the monotonic loading phase and resulted from tendon stripping. No suture or knot failure was observed. The mean loads resisted by the configurations ranged from 138 to 398 N. The mean load to failure, maximum load resisted prior to 1 cm of distension, and load resisted at 1 cm of distension were significantly lower for the vertical mattress suture group than for any of the other three groups (p < 0.031). CONCLUSIONS All four groups sustained loads well above the physiologic loads expected to occur in tendons in the foot and ankle (e.g., in tendon transfer for tibialis posterior tendon insufficiency). None of the four side-to-side configurations distended appreciably during the cyclic loading phase. The vertical mattress suture configuration appeared to be weaker than the other configurations. CLINICAL RELEVANCE For surgeons who advocate immediate loading or motion of a side-to-side tendon repair, a pulley, running locked, or simple eight suture technique appears to provide a larger safety margin compared with a vertical mattress suture technique.
Techniques in Foot & Ankle Surgery | 2017
Pablo Wagner; Cristian Ortiz; Emilio Wagner
More than 200 different surgical techniques exist for hallux valgus (HV). Some of them are designed for mild, moderate, or severe deformities depending on their correction power. Nevertheless, they all correct only the coronal and/or sagittal plane deformity. Just a handful of them correct the known axial malrotation that exists in most HV cases. This malrotation is one possible factor that could be the source of recurrence of an operated HV as it has been described. We describe a new technique which simultaneously corrects the metatarsal internal rotation and varus deformity by rotating the metatarsal through an oblique plane osteotomy. This is performed with no bone wedge resection. Also, there is a broader bone surface contact than on a transverse proximal osteotomy. This technique is easy to remember and relatively simple to perform in primary and revision cases. The authors results show that it is as safe and effective as other procedures, with some advantages to be discussed. Levels of Evidence: Diagnostic Level 5. See Instructions for Authors for a complete description of levels of evidence.
Foot & Ankle International | 2015
Emilio Wagner; Cristian Ortiz; Francisco Figueroa; Omar Vela; Pablo Wagner; John S. Gould
Background: Hallux valgus (HV) treatment is continuously evolving, and no definitive treatment can be recommended. Osteotomies are the main surgical choice for these deformities, but no clear role for soft tissue procedures is available. Objective: To perform a retrospective comparison of the radiographic and clinical outcomes of 2 groups of patients with severe HV operated with the same osteotomy technique but differing on the type of lateral release. Methods: Two groups of patients with symptomatic moderate to severe HV deformities were operated with the same proximal metatarsal osteotomy, which differed on the type of lateral release: group 1 had limited transarticular lateral capsule release (n = 62), and group 2 complete lateral release, including capsule, adductor tendon, and intermetatarsal (IM) ligament (n = 57). We recorded the American Orthopaedic Foot & Ankle Society (AOFAS) score, HV and IM angles, first metatarsal shortening, concomitant metatarsal shortening osteotomies (Weil), Akin osteotomies, and complications. Results: The postoperative AOFAS score in group 1 was similar to that of group 2. The HV and IM angles improved in both groups with no significant difference. The multivariate analysis showed no influence of any variable analyzed on HV or IM angle improvement. Regarding AOFAS score improvement, a limited lateral release was associated with a higher increase in AOFAS score (P = .019). Conclusion: No studies are available to identify which soft tissue structures are involved in HV deformities nor which have to be released, if any. A limited transarticular release can provide similar clinical and radiologic outcomes when compared with a classic open lateral release. Level of Evidence: Level IV, case series.
SICOT-J | 2017
Pablo Wagner; Rolf D. Burghardt; Stuart A. Green; Stacy C. Specht; Shawn C. Standard; John E. Herzenberg
Introduction: Femoral/tibial lengthening with a telescopic, magnetically-powered, intramedullary nail is an alternative to lengthening with external fixation. Methods: Pre-clinical testing was conducted of the PRECICE in a human cadaver. A retrospective review of the first 30 consecutive patients who underwent unilateral lengthening was also conducted. Nail accuracy was obtained by comparing the amount of nail distraction to the final bone length achieved at the end of the distraction process. Relative standard deviation of accuracy was used to calculate nail precision. Results: Devices performed successfully in a human cadaver. Thirty consecutive patients (10 females, 20 males; mean age, 23 years) with limb length discrepancy (LLD) were followed an average of 19 months (range, 12–24 months). Etiology included congenital shortening (14), posttraumatic deformities (7), Ollier disease (3), osteosarcoma resection (1), prior clubfoot (2), hip dysplasia (1), post-septic growth arrest of knee (1), and LLD after hip arthroplasty (1). Twenty-four femoral and eight tibial nails were implanted. Mean preoperative lengthening goal was 4.4 cm (range, 2–6.5 cm); mean postoperative length achieved was 4.3 cm (range, 1.5–6.5 cm). Average consolidation index was 36.4 days/cm (range, 12.8–113 days/cm). Mean nail accuracy was 97.3% with a precision of 92.4%. Average preoperative and 12-month postoperative Enneking scores were 21.5 and 25.3 (p < 0.001), respectively. The preoperative and 12-month postoperative SF-12 physical and mental component scores were not statistically different. Nine complications (nine limb segments) resolved: two partial femoral unions, two suspected deep vein thrombosis (DVT), one delayed tibial union, one fibular nonunion, one peroneal nerve irritation, one knee joint subluxation, and one confirmed DVT. Twenty-nine (91%) of 32 limb segments achieved successful bone healing without revision surgery. Discussion: Limb lengthening with PRECICE is reliable, but larger trials with longer follow-up will reveal limitations. Implantable nails prevent problems associated with external fixation, such as muscle tethering and pin-site infections.
Foot & Ankle International | 2016
Cristian Ortiz; Pablo Wagner; Omar Vela; Daniel Fischman; Gabriel Cavada; Emilio Wagner
Background: The most common methods for assessing severity of hallux valgus deformity and the effects of an operative procedure are the angular measurements in weightbearing radiographs, specifically the hallux valgus angle and intermetatarsal angle (IMA). Our objective was to analyze the interobserver variability in hallux valgus patients of a new angle called the “angle to be corrected” (ATC), and to compare its capacity to differentiate between different deformities against IMA. Methods: We included 28 symptomatic hallux valgus patients with 48 weightbearing foot x-rays. Three trained observers measured the 1 to 2 IMA and the ATC. We then identified retrospectively 45 hallux valgus patients, which were divided into 3 operative technique groups having used the ATC as reference, and analyzed the capacity of the IMA to differentiate between them. Results: The IMA average value was 13.6 degrees, and there was a significant difference between observer 3 and observer 1 (P = .001). The average value for the ATC was 8.9 degrees, and there was no difference between observers. Both angles showed a high intraclass correlation. Regarding the capacity to differentiate between operative technique groups, the ATC was different between the 3 operative technique groups analyzed, but the IMA showed differences only between 2. Conclusions: The ATC was at least as reliable as the intermetatarsal angle for hallux valgus angular measurements, showing a high intraclass correlation with no interobserver difference. It can be suggested that the ATC was better than the IMA to stratify hallux valgus patients when deciding between different operative treatments. Level of Evidence: Level III, comparative study.
Journal of Pediatric Orthopaedics | 2017
Pablo Wagner; Shawn C. Standard; John E. Herzenberg
Background: The multiplier method (MM) is frequently used to predict limb-length discrepancy and timing of epiphysiodesis. The traditional MM uses complex formulae and requires a calculator. A mobile application was developed in an attempt to simplify and streamline these calculations. We compared the accuracy and speed of using the traditional pencil and paper technique with that using the Multiplier App (MA). Methods: After attending a training lecture and a hands-on workshop on the MM and MA, 30 resident surgeons were asked to apply the traditional MM and the MA at different weeks of their rotations. They were randomized as to the method they applied first. Subjects performed calculations for 5 clinical exercises that involved congenital and developmental limb-length discrepancies and timing of epiphysiodesis. The amount of time required to complete the exercises and the accuracy of the answers were evaluated for each subject. Results: The test subjects answered 60% of the questions correctly using the traditional MM and 80% of the questions correctly using the MA (P=0.001). The average amount of time to complete the 5 exercises with the MM and MA was 22 and 8 minutes, respectively (P<0.0001). Conclusions: Several reports state that the traditional MM is quick and easy to use. Nevertheless, even in the most experienced hands, performing the calculations in clinical practice can be time-consuming. Errors may result from choosing the wrong formulae and from performing the calculations by hand. Our data show that the MA is simpler, more accurate, and faster than the traditional MM from a practical standpoint. Level of Evidence: Level II.
Journal of surgical orthopaedic advances | 2013
Emilio Wagner; Cristian Ortiz; Andres Keller; Gregorio Verschae; Pablo Wagner; John S. Gould
Proximal metatarsal osteotomies are inherently unstable and difficult to fix. The purpose of this study was to compare the mechanical stiffness in sawbone models of medially versus dorsally placed plates and then to compare semilocked versus nonlocked plates in different osteotomy configurations. Thirty sawbone models were constructed, fixed either with titanium self-locking or steel mini-fragment plates. They were divided in groups and their stiffness was measured. The stiffness of any model fixed with medial titanium or steel plates was on average 158% and 228% greater, respectively, compared to dorsal plates. Adding a dorsal shelf of bone to a proximal closing wedge osteotomy increases its stiffness. Using locked plates increased the mechanical stiffness in only one configuration. The article suggests that models fixed with medial plates have greater resistance to failure than models fixed with dorsal plates. Using locked plates does not increase the mechanical stiffness of the construct.
Foot & Ankle International | 2018
Emilio Wagner; Pablo Wagner; Cristian Ortiz; Ruben Radkievich; Felipe Palma; Rodrigo Guzmán-Venegas
Background: No clear guideline or solid evidence exists for peroneal tendon tears to determine when to repair, resect, or perform a tenodesis on the damaged tendon. The objective of this study was to analyze the mechanical behavior of cadaveric peroneal tendons artificially damaged and tested in a cyclic and failure mode. The hypothesis was that no failure would be observed in the cyclic phase. Methods: Eight cadaveric long leg specimens were tested on a specially designed frame. A longitudinal full thickness tendon defect was created, 3 cm in length, behind the tip of the fibula, compromising 66% of the visible width of the peroneal tendons. Cyclic testing was initially performed between 50 and 200 N, followed by a load-to-failure test. Tendon elongation and load to rupture were measured. Results: No tendon failed or lengthened during cyclic testing. The mean load to failure for peroneus brevis was 416 N (95% confidence interval, 351–481 N) and for the peroneus longus was 723 N (95% confidence interval, 578–868 N). All failures were at the level of the defect created. Conclusion: In a cadaveric model of peroneal tendon tears, 33% of remaining peroneal tendon could resist high tensile forces, above the physiologic threshold. Clinical Relevance: Some peroneal tendon tears can be treated conservatively without risking spontaneous ruptures. When surgically treating a symptomatic peroneal tendon tear, increased efforts may be undertaken to repair tears previously considered irreparable.