Papers by Norman Espinosa
ABSTRACT PURPOSE To determine the frequency and degree of fatty muscle atrophy in plantar foot mu... more ABSTRACT PURPOSE To determine the frequency and degree of fatty muscle atrophy in plantar foot muscles in asymptomatic volunteers and in patients with non-specific foot pain. Fatty muscle atrophy may be considered to represent neuropathy. METHOD AND MATERIALS Frequency and degree of fatty atrophy was determined with MR imaging in abductor digiti minimi, flexor digitorum brevis, abductor hallucis and quadratus plantae muscles in 80 asymptomatic volunteers (mean age 48, range 23 – 84 years) and in 80 age and gender matched patients (mean age 48, range 20 – 86 years) with foot pain (no trauma, tumor or infection). Muscles were graded as normal (0), mild fatty atrophy with still more muscle than fat (1), and substantial fatty atrophy with equal or more fat than muscle (2) by two readers separately. Results of the visual grading (volunteers vs. patients) for both readers were compared using the Mann-Whitney-U-Test. Association of age and degree of fatty atrophy was assessed using the Kruskal-Wallis-Test. RESULTS Reader 1 and 2 found substantial fatty atrophy of the abductor digiti minimi muscle in 4 (5%) and in 5 (6%) volunteers, as well as 3 (4%) and 9 (11%) patients. One reader diagnosed substantial fatty atrophy of the abductor hallucis in 3 (4%) and of the flexor digitorum brevis in 2 (2.5%) volunteers. Frequency for the quadratus plantae varied between 0 and 1 (1%). A significant association of age and degree of fatty atrophy was found for the abductor digiti minimi muscle of volunteers (both readers) and patients (reader 1) (P values <0.01). CONCLUSION Fatty atrophy of abductor digiti minimi – considered to represent entrapment neuropathy, has a frequency between 4 – 11% in asymptomatic volunteers and in patients with foot pain. Prevalence of fatty atrophy of the abductor digiti minimi is increasing with age in asymptomatic volunteers. CLINICAL RELEVANCE/APPLICATION The clinical relevance of fatty atrophy of the abductor digiti minimi muscle is uncertain since its prevalence is similar in patients with foot pain and asymptomatic volunteers.
Primary and Revision Total Ankle Replacement, 2015
The Journal of bone and joint surgery. American volume, 2005
... Total sacrectomy and reconstruction with structural allografts for neurofibrosarcoma of the s... more ... Total sacrectomy and reconstruction with structural allografts for neurofibrosarcoma of the sacrum : A case report. Auteur(s) / Author(s). KAN MIN ; ESPINOSA Norman ; BODE Beata ; EXNER Gerhard U. ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). ...
Seminars in musculoskeletal radiology, 2010
This review article describes the postoperative magnetic resonance (MR) findings relating to surg... more This review article describes the postoperative magnetic resonance (MR) findings relating to surgery after tendon repair, ligament repair, and Morton's neuroma resection. The normal postoperative tendon is commonly thickened, showing signal changes that are most pronounced 3 to 6 months after surgery. Two years after tendon suture, the signal intensity should be low on T2-weighted images. The focus of the postoperative MR imaging after ankle repair is to detect the normal condition after the various surgical procedures (e.g., Broström, Watson-Jones, Evans, or Chrisman-Snook). The repaired ligament has to be visible, low signal intense on T2-weighted MR images, and the shape should be homogeneous. A high rate (26%) of so-called Morton's neuroma recurrences is seen in asymptomatic individuals after Morton's neuroma resection. Postoperatively, intermetatarsal bursitis MR abnormalities are more commonly encountered in symptomatic intermetatarsal spaces than in asymptomatic i...
Foot and ankle clinics, 2013
This article discusses the lack of scientific evidence regarding the treatment of failed joint-pr... more This article discusses the lack of scientific evidence regarding the treatment of failed joint-preserving surgery. Most of the concepts of treatment derive from treatment modalities in trauma and orthopedic surgery. The main question for the foot and ankle specialist is whether the joint can be salvaged. The definition of failure is difficult. Therefore pain reported by the patient is the main symptom that dictates the course of treatment. Whenever possible the joint should be maintained. However, if pain is associated with global radiographic osteoarthritis, total ankle replacement or fusions are the only means to solve the problem.
Foot and ankle clinics, 2012
Understanding biomechanics of the normal and arthritic ankle joint can aid in analysis of an unde... more Understanding biomechanics of the normal and arthritic ankle joint can aid in analysis of an underlying clinical problem and provide a strategic basis for a more optimal management. The challenge to the clinician and the biomechanist is that the mechanical complexity of the ankle joint still clouds current understanding. This article provides an overview of current understanding of functional ankle anatomy, how this function can be altered in the degenerated ankle, and how surgical intervention further affects foot and ankle biomechanics. The focus is on how altered loading of neighboring joints in the midfoot and hindfoot may induce postoperative joint remodeling and can manifest in secondary clinical problems.
Foot and ankle clinics, 2012
Clinics in podiatric medicine and surgery, 2013
Total ankle replacement has become a popular treatment of symptomatic end-stage ankle osteoarthri... more Total ankle replacement has become a popular treatment of symptomatic end-stage ankle osteoarthritis. Contemporary total ankle replacement systems provide more anatomic and biomechanically sound function. However, longevity is still limited and long-term results of modern total ankle replacement designs are not available. In the case of failure, conversion into arthrodesis has remained the treatment of choice but at the cost of hindfoot function and potential degeneration of the adjacent joints. Thus, revision total ankle replacement by exchange of the prosthetic components represents an attractive solution. This article focuses on revision total ankle replacement and conversion to ankle arthrodesis.
Foot and ankle clinics, 2011
This article focuses on arthrodesis of the first tarsometatarsal joint as the primary interventio... more This article focuses on arthrodesis of the first tarsometatarsal joint as the primary intervention to treat hypermobility of the first ray or as a salvage procedure to treat prior failed bunion surgery and provides a concise review including historical perspective, definitions, pathomechanics, and treatment of specific forefoot disorders (ie, hypermobility of the first ray and failed bunion surgery).
Essential Orthopaedics, 2010
Essential Orthopaedics, 2010
Radiology, 2009
To determine prevalence and degree of fatty muscle atrophy in plantar foot muscles in asymptomati... more To determine prevalence and degree of fatty muscle atrophy in plantar foot muscles in asymptomatic volunteers and in patients with foot pain. Institutional review board approval and informed consent were obtained. The prevalence and degree of fatty muscle atrophy were evaluated with magnetic resonance imaging in the abductor digiti minimi (ADM), flexor digitorum brevis (FDB), abductor hallucis (AH), and quadratus plantae (QP) muscles in 80 asymptomatic volunteers (mean age, 48 years; range, 23-84 years) and 80 patients with foot pain (mean age, 48 years; range, 20-86 years). Muscles were characterized as normal (grade 0) or as having mild (grade 1) or substantial (grade 2) fatty atrophy by two readers separately. Results of visual grading for both readers were compared by using the Mann-Whitney test. Associations between age and degree of fatty muscle atrophy were assessed by using the Kruskal-Wallis test. Readers 1 and 2 found substantial fatty atrophy of the ADM muscle in four (5%) and five (6%) volunteers, respectively, and in three (4%) and nine (11%) patients, respectively. One reader diagnosed substantial fatty atrophy of the AH muscle in three (4%) volunteers and of the FDB muscle in two (2%) volunteers. Prevalence for the QP muscle varied between 0% and 1%. An association between age and degree of fatty atrophy of the ADM muscle was found for volunteers by both readers and for patients by reader 1 (P < .01). Prevalence of fatty muscle atrophy of the ADM muscle-classically considered to represent entrapment neuropathy-is between 4% and 11% in both asymptomatic volunteers and patients with foot pain, and it increases with age.
The Journal of Bone and Joint Surgery (American), 2010
Background: A major cause of the limited longevity of total ankle replacements is premature polye... more Background: A major cause of the limited longevity of total ankle replacements is premature polyethylene component wear, which can be induced by high joint contact pressures. We implemented a computational model to parametrically explore the hypothesis that intercomponent positioning deviating from the manufacturer's recommendations can result in pressure distributions that may predispose to wear of the polyethylene insert. We also investigated the hypothesis that a modern mobile-bearing design may be able to better compensate for imposed misalignments compared with an early two-component design.
Foot & Ankle International, 2012
When performing subtalar arthrodesis, proper screw placement is fundamental to provide primary st... more When performing subtalar arthrodesis, proper screw placement is fundamental to provide primary stability and to help ensure bone healing. In inexperienced hands this step can be time-consuming and exposes surgeons and patients to radiation. By means of a targeting device these potential drawbacks and dangers could be reduced. It was hypothesized that a specifically designed targeting device would reduce radiation exposure while improving screw placement when compared with the conventional "free-hand'' method. Twenty matched-pairs of cadaveric hindfoot specimens (Thiel fixation) were prepared for the purpose of the study. The specimens were randomly assigned into two groups consisting of 10 specimens each: in Group 1 screw placement was performed with the targeting device and in Group 2 screw placement was performed under fluoroscopic control. Screw placement was radiographically judged to be optimal, suboptimal and poor. An experienced, fellowship-trained foot and ankle surgeon and a resident, who had never done subtalar fusions performed the screw placements. Exposure to radiation was assessed by means of the dose area product given by the fluoroscope. Optimal screw positioning was achieved in both groups in ten out of 20 specimens (Group 1, n=5; Group 2, n=5). Suboptimal screw placement was found in eight cases (Group 1, n=4; Group 2, n=4). There were two failures which occurred in fusions performed by the resident (Group 1, n=1; Group 2, n=1). Exposure to radiation was significantly reduced in Group 1 when compared with Group 2 (4.1cGy* cm2 versus 8.1cGy* cm2; p=0.012). No lesion of neurovascular structures due to aiming device placement occurred in Group 1. A target-device for screw-placement did not provide a significant technical advantage but did result in less radiation exposure.
Foot & Ankle International, 2008
Calcaneonavicular coalitions (CNC) have been reported to be associated with anatomical aberration... more Calcaneonavicular coalitions (CNC) have been reported to be associated with anatomical aberrations of either the calcaneus and/or navicular bones. These morphological abnormalities may complicate accurate surgical resection. Three-dimensional analysis of spatial orientation and morphological characteristics may help in preoperative planning of resection. Sixteen feet with a diagnosis of CNC were evaluated by means of 3-D CT modeling. Three angles were defined that were expressed in relation to one reproducible landmark (lateral border of the calcaneus): the dorsoplantar inclination, anteroposterior inclination, and socket angle. The depth and width of the coalitions were measured and calculated to obtain the estimated contact surface. Three-dimensional reconstructions of the calcanei served to evaluate the presence, distortion or absence of the anterior calcaneal facet and presence of a navicular beak. The interrater correlations were assessed in order to obtain values for the accuracy of the measurement methods. Sixteen normal feet were used as controls for comparison of the socket angle; anatomy of the anterior calcaneal facet and navicular beak as well. The dorsoplantar inclination angle averaged 50 degrees (+/-17), the anteroposterior inclination angle 64 degrees (+/-15), and the pathologic socket angle 98 degrees (+/-11). The average contact area was 156 mm(2). Ninety-four percent of all patients in the CNC group revealed a plantar navicular beak. In 50% of those patients the anterior calcaneal facet was replaced by the navicular portion and in 44% the facet was totally missing. In contrast, the socket angle in the control group averaged 77 degrees (+/-18), which was found to be statistically different than the CNC group (p = 0.0004). Only 25% of the patients in the control group had a plantar navicular beak. High, statistically significant interrater correlations were found for all measured angles. Computer-aided CT analysis and reconstructions help to determine the spatial orientations of CNC in space and provide useful information in order to anticipate morphological abnormalities of the calcaneus and navicular.
European Spine Journal, 2008
This report describes the spinal fixation with pedicle-screw-alone constructs for the posterior c... more This report describes the spinal fixation with pedicle-screw-alone constructs for the posterior correction of scoliosis in patients suffering from Duchene muscular dystrophy (DMD). Twenty consecutive patients were prospectively followed up for an average of 5.2 years (min 2 years). All patients were instrumented from T3/T4 to the pelvis. Pelvic fixation was done with iliac screws similar to Galveston technique. The combination of L5 pedicle screws and iliac screws provided a stable caudal foundation. An average of 16 pedicle screws was used per patient. The mean total blood loss was 3.7 l, stay at the intensive care unit was 77 h and hospital stay was 19 days. Rigid stabilisation allowed immediate mobilisation of the patient in the wheel chair. Cobb angle improved 77% from 44°to 10°, pelvic tilt improved 65% from 14°to 3°. Lumbar lordosis improved significantly from 20°to 49°, thoracic kyphosis remained unchanged. No problems related to iliac fixation, no pseudarthrosis or implant failures were observed. The average percentage of predicted forced vital capacity (%FVC) of the patients was 55% (22-94%) preoperatively and decreased to 44% at the last follow-up. There were no pulmonary complications. One patient with a known cardiomyopathy died intraoperatively due to a sudden cardiac arrest. The rigid primary stability with pedicle screws allowed early mobilisation of the patients, which helped to avoid pulmonary complications.
European Radiology, 2014
Objectives To quantify the muscle fat-content (MFC) in phantoms, volunteers and patients with ach... more Objectives To quantify the muscle fat-content (MFC) in phantoms, volunteers and patients with achillodynia using twopoint Dixon-based magnetic resonance imaging (2pt-MRI DIXON ) in comparison to MR spectroscopy (MRS) and visual assessment of MFC. Methods Two-point Dixon-based MRI was used to measure the MFC of 15 phantoms containing 0-100 % fat-content and calf muscles in 30 patients (13 women; 57±15 years) with achillodynia and in 20 volunteers (10 women; 30±14 years) at 1.5 T. The accuracy of 2pt-MRI DIXON in quantification of MFC was assessed in vitro using phantoms and in vivo using MRS as the standard of reference. Fat-fractions derived from 2pt-MRI DIXON (FF DIXON ) and MRS (FF MRS ) were related to visual assessment of MFC (Goutallier grades 0-4) and Achilles-tendon quality (grade 0-4).
European Journal of Trauma and Emergency Surgery, 2010
While ankle arthrodesis has remained the gold standard treatment for symptomatic primary, seconda... more While ankle arthrodesis has remained the gold standard treatment for symptomatic primary, secondary, and posttraumatic ankle arthritis, more recently, total ankle replacement (TAR) has seen considerable improvement in terms of biomechanics, function, and complication rates. However, while in the long-term degeneration of the adjacent joints is almost always found on radiographs after ankle arthrodesis, the longevity of TAR is still insufficient and does not match that of total knee and hip joints. The current review article focuses on the treatment of ankle arthritis by means of arthrodesis and TAR.
Clinical Orthopaedics and Related Research, 2001
The optimal treatment of shoulder stiffness remains controversial. The current authors reviewed t... more The optimal treatment of shoulder stiffness remains controversial. The current authors reviewed the results of arthroscopic capsular release of 45 stiff shoulders in 45 patients that was done after the patients did not respond to conservative treatment. There were nine idiopathic frozen shoulders, 21 that had postoperative stiffness, and 15 shoulders with stiffness after trauma. At a mean followup of 26 months (minimum, 12 months), arthroscopic capsular release improved the subjective shoulder value from 25% to 68% and the age- and gender-adjusted Constant-Murley score from 41% to 75%. Pain improved from 4.7 to 10.9 of 15 points. Active, pain-free anterior elevation increased from 90 degrees to 128 degrees and external rotation increased from 14 degrees to 31 degrees. The quality of sleep improved from 0.5 to 1.6 on a two-point scale. The only improvement that did not reach statistical significance was the improvement in the ability to work. A retrospective analysis of the results stratified according to the etiology of stiffness showed that the outcome after treatment of idiopathic stiffness was better than after postoperative stiffness and that the results of treatment for posttraumatic stiffness were least favorable. The difference between preoperative state and followup, however, was not statistically significantly different from one group to another. All groups improved significantly and to a similar degree but the final outcome was related to the initial degree of disability. Arthroscopic release is an effective method for treatment of shoulder stiffness; however, the ultimate outcome is related directly to the severity of stiffness regardless of the etiology.
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Papers by Norman Espinosa