Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Theodore A. Xenakis is active.

Publication


Featured researches published by Theodore A. Xenakis.


Journal of Bone and Joint Surgery, American Volume | 1997

School-screening for scoliosis : A prospective epidemiological study in northwestern and central Greece

Panayotis N. Soucacos; Panayotis K Soucacos; Konstantinos C. Zacharis; Alexandros E. Beris; Theodore A. Xenakis

A two-year prospective study was done to assess the prevalence and distribution of various parameters associated with scoliosis in schoolchildren in northwestern and central Greece. A total of 82,901 children (41,939 boys and 40,962 girls) who were nine to fourteen years old were screened for scoliosis. Five thousand eight hundred and three children had clinical signs of scoliosis and, of these, 4185 were referred for posteroanterior radiographs (to be made with the patient standing) because they had a positive result on the forward-bending test (a difference of more than five millimeters between the two sides of the torso as measured in the thoracic or thoracolumbar region with use of a ruler and a level plane) at the time of a second screening. The prevalence of scoliosis (defined as a curve of 10 degrees or more) was 1.7 per cent (1436 of 82,901 children), and most of the curves (1255; prevalence, 1.5 per cent) were small (10 to 19 degrees). The ratio of boys to girls was 1:2.1 over-all but varied according to the magnitude of the curve (1:1.5 for curves of less than 10 degrees, 1:2.7 for curves of 10 to 19 degrees, 1:7.5 for curves of 20 to 29 degrees, 1:5.5 for curves of 30 to 39 degrees, and 1:1.2 for curves of 40 degrees or more). Thoracolumbar curves were the most common type of curve identified, followed by lumbar curves; specifically, of the 1436 children who had a curve of at least 10 degrees, 493 (34.3 per cent) had a thoracolumbar curve, 475 (33.1 per cent) had a lumbar curve, 261 (18.2 per cent) had a thoracic curve, and 207 (14.4 per cent) had a double curve. Although most (753) of these curves were to the left, the left:right ratio varied according to the location of the apex of the curve (1:3.1 for thoracic curves, 2.0:1 for thoracolumbar curves, and 3.2:1 for lumbar curves). The cost of the screening process was negligible (estimated at thirty cents per child); however, the decreased number of operative procedures performed in children from the geographical area of our University Hospital, the identification of a large number of previously undiagnosed curves (eleven of which were treated operatively and 170 of which were treated with a brace), and the identification of children who were at high risk for progression were considered important benefits of the school-screening program.


Knee | 2008

Transtibial versus anteromedial portal of the femoral tunnel in ACL reconstruction: A cadaveric study

Iosif Gavriilidis; Efstathios K Motsis; Emilios E. Pakos; Anastasios D. Georgoulis; Gregory Mitsionis; Theodore A. Xenakis

The aim of this cadaveric study was to compare the transtibial versus the anteromedial portal with respect to the anatomic femoral positioning of the ACL attachment. Ten fresh frozen cadaveric knees were included in our study. A standard arthroscopy was performed and the normal ACL was partially cut through with arthroscopic scissors leaving a small footprint of 2 mm at the anatomical insertion area on the lateral femoral condyle. The femoral tunnel was drilled through the tibial tunnel and subsequently through the anteromedial portal. Using a probe with standard magnification, we measured the distances of the two femoral tunnels from the margin of ACL footprint arthroscopically. The femurs were then dissected and we measured the distances of the two tunnels from the posterior part of the lateral femoral condyle. The median arthroscopically measured distance of the centers of transtibial femoral tunnel and of the femoral tunnel through the anteromedial portal from the margin of the femoral ACL footprint were 6.20 mm and 2.80 mm respectively. The difference was statistically significant. After femoral dissection the median distance of the centers of the transtibial femoral tunnel and the femoral tunnel performed through the anteromedial portal from the border of the articular surface at the lateral femoral condyle was 6.10 mm and 5.25 mm respectively (p<0.001). Both measurements showed that ACL reconstruction technique through the anteromedial portal is more accurate compared to the transtibial technique.


Clinical Orthopaedics and Related Research | 1997

Surgical treatment of malleolar fractures. A review of 144 patients.

Alexandras E Beris; Khaled T. Kabbani; Theodore A. Xenakis; Gregory Mitsionis; Panayotis K Soucacos; Panayotis N. Soucacos

Malleolar fractures are one of the most common fractures faced in orthopaedic surgery. The results from a consecutive series of 144 malleolar fractures during a 10-year period that were classified and treated according to the AO system are presented. Assessment of outcome was done using the scoring system of Baird and Jackson, which is based on subjective, objective, and radiographic criteria. Excellent and good results were achieved in 107 of the 144 patients surgically treated. Overall, excellent and good results were obtained in almost all unimalleolar fractures, but were significantly less in bimalleolar fractures. There was no difference in outcome achieved between Weber C and Weber D fractures. The presence of a large bony fragment or dislocation also significantly affected the final outcome. Posttraumatic osteoarthritis was found to be associated significantly with poor clinical results, bimalleolar fractures, and unsatisfactory surgical reduction.


Clinical Orthopaedics and Related Research | 2001

Cementless hip arthroplasty in the treatment of patients with femoral head necrosis.

Theodore A. Xenakis; John Gelalis; Theodosios A. Koukoubis; Konstantinos C. Zaharis; Panayotis N. Soucacos

Treatment of patients with osteonecrosis of the femoral head focuses on pain relief and improved function of the hip. Total hip arthroplasty remains an effective tool for the treatment of patients with end-stage osteonecrosis with collapse of the femoral head, although there is a greater risk for failure. The aim of the current study was to assess the long-term survival of cementless total hip arthroplasties in 28 patients (36 hips) with osteonecrosis of the femoral head (Steinberg Stage V and Stage VI) with an average followup of 11.2 years (range, 10–15 years). There were 19 women and nine men with an average age of 51.4 years (range, 28–65 years). A threaded titanium cup CST (Conical Screwed Titanium) was used in all patients and different cementless femoral components were used depending on the optimal fit in the femoral canal as assessed during preoperative templating. No serious complications were encountered postoperatively. The patients were evaluated preoperatively and postoperatively with the Merle d’Aubigné and Postel scale. After cementless total hip arthroplasty, the average pain score improved 3.6 points, walking ability improved 1.6 points, and range of motion improved 1 point. Two patients had thigh pain. Radiographic evaluation on anteroposterior and lateral radiographs of the proximal femur was excellent in 10 hips postoperatively. No heterotropic ossification was observed, although proximal femoral atrophy was seen in 15 hips. Clinical and radiologic findings did not correlate. There were two revisions of the acetabular implants in one patient with bilateral idiopathic osteonecroses and total hip replacement. Overall, survival of the prostheses was 93.4% at the average followup of 11.2 years.


Clinical Orthopaedics and Related Research | 1997

Total hip arthroplasty for avascular necrosis and degenerative osteoarthritis of the hip.

Theodore A. Xenakis; Alexandros E. Beris; Konstantinos K. Malizos; Theodosios Koukoubis; John Gelalis; Panayotis N. Soucacos

Although several studies of various treatment modalities have been reported during the past decade, osteonecrosis of the femoral head remains a difficult therapeutic problem. Total hip replacement which is reserved for patients showing collapse of the femoral head, usually shows poorer results in patients with osteonecrosis compared with those with osteoarthritis. Uncemented total hip arthroplasty was performed on 29 patients with avascular necrosis of the femoral head and 29 patients with degenerative osteoarthritis. After a mean followup of 7.6 years and 7.1 years for the two groups of patients, only one failure was observed in one patient with osteonecrosis. Clinical evaluation after cementless total hip arthroplasty in both groups of patients revealed improvement in all parameters. Postoperatively, pain improved from 1.4 to 5.1, walking ability from 3.4 to 5.3, and range of motion from 4.5 to 5.5 in patients with osteonecrosis, and pain improved from 1.2 to 5.3, walking ability from 3.2 to 5.4, and range of motion from 3.1 to 4.7 in patients with osteoarthritis. Thigh pain was observed postoperatively in only two and three patients treated for osteonecrosis and osteoarthritis, respectively. The present results using cementless arthroplasty seem to be somewhat better than those reported for cemented arthroplasty in patients suffering from osteonecrosis. The clinical and radiographic findings after non-cemented arthroplasty in patients with osteonecrosis of the femoral head and in patients with degenerative arthritis of the hip were similar in the two groups.


Orthopedics | 2000

Risk Factors for Idiopathic Scoliosis: Review of a 6-Year Prospective Study

Panayotis N. Soucacos; Konstantinos C. Zacharis; Konstantinos Soultanis; John Gelalis; Theodore A. Xenakis; Alexandros E. Beris

This study identified factors associated with the prevalence of idiopathic scoliosis and curve evolution in schoolchildren from northwestern and central Greece. A total of 85,627 children aged 9-15 years were screened for scoliosis. A subset of children with curves of at least 10 degrees underwent clinical and radiographic follow-up. The total population screened and the cohort followed for curve progression were evaluated according to factors associated with curve evolution. The prevalence of scoliosis was 1.7%, with most cases appearing at ages 13 and 14 years and small scoliotic curves (10 degrees-19 degrees) being most prevalent (prevalence 1.5%). Prevalence was associated with gender; age; and magnitude, apex, and direction of the curve. Progression of the curve occurred in 14.7% of 839 children, while 27.4% demonstrated spontaneous improvement of at least 5 degrees. A high risk of curve progression was associated with the following: sex--girls, curve pattern--right thoracic and double curves in girls and right lumbar in boys, maturity--girls before the onset of menses, age--time of pubertal growth spurt, and curve magnitude--curves > or = 30 degrees. Although only a small percentage of scoliotic curves undergo progression, the pattern of the curve according to curve direction and the sex of the child plays a significant role in the ability to identify which curves will progress.


Journal of Arthroplasty | 1996

Neglected Congenital Dislocation of the Hip Role of Computed Tomography and Computer-Aided Design for Total Hip Arthroplasty

Theodore A. Xenakis; Ioannis D. Gelalis; Theodosios D. Koukoubis; Panayotis N. Soucacos; Kostas Vartziotis; Dimitrios Kontoyiannis; Christos Tatsis

Computed tomography (CT) provides important three-dimensional anatomic details in congenital dislocation of the hip that are useful for total hip arthroplasty (THR) and are not obtainable with conventional radiographic evaluation. In this study, 84 patients (119 hips) with congenital dislocation of the hip were evaluated with CT before surgery. Specifically, both the acetabulum and the femur were analyzed to make the best selection of the prosthesis. The average anteversion of the acetabulum was 23 degrees, with an opening of 30.9 mm and a depth of 14.7 mm. The bone stock of the true acetabulum was calculated and the average available diameter for the acetabular implant was 44.9 mm. The CT topogram revealed the true leg-length discrepancy (average 0.5-1.9 cm), and the amount of a shortening osteotomy when necessary was determined. Finally, to determine the stem with optimum fit and fill, a three-dimensional reconstruction of the femoral canal using CT data and computer-aided design (CAD) was matched with a three-dimensional geometry of several stem designs and sizes obtained from a CAD system.


Journal of Arthroplasty | 2008

Distal Femoral Shortening in Total Hip Arthroplasty for Complex Primary Hip Reconstruction. A New Surgical Technique

Panagiotis Koulouvaris; Kosmas Stafylas; Thomas P. Sculco; Theodore A. Xenakis

Successful total hip arthroplasty (THA) in congenital dislocated hips demands anatomical reduction in the normal center of rotation without overstretching the sciatic nerve and without excessive compression or abnormal forces across the joint. Proximal femoral and subtrochanteric shortening osteotomy has been described for THA for the treatment of dislocated hips. However, these osteotomies are demanding, associated with deformation of femoral canal and nonunion, and may increase the femoral stem stress. This study reports excellent results in 24 patients with a new surgical technique that combines THA with a distal femoral shortening in severely deformed hips using customized components.


Acta Orthopaedica Scandinavica | 1997

Knee dislocations and their management: A report of 16 cases

K. N. Malizos; Theodore A. Xenakis; Alexandras N Mavrodontidis; Andreas Xanthis; Anastasios B. Korobilias; Panayotis N. Soucacos

We retrospectively studied the outcome of 16 knee dislocations. 11 patients had surgical treatment, 4 were managed nonoperatively and 1 patient died. In the elderly the outcome was poor, regardless of the type of treatment. Only 3 adolescents obtained excellent results and 2 young adults had good results after surgical repair of the knee. Concurrent arterial and nerve damage increased the morbidity.


Acta Orthopaedica Scandinavica | 1997

Bridge plating osteosynthesis of 20 comminuted fractures of the femur

John P Chrisovitsinos; Theodore A. Xenakis; Kostas G Papakostides; Nicholas Skaltsoyannis; Anastasios Grestas; Panayotis N. Soucacos

We retrospectively studied the outcome of 20 comminuted fractures (20 patients, 15 men) of the femur treated in accordance with the principles of indirect reduction and biological osteosynthesis technique. The patients were followed for mean 1.5 (1-4.5) years. 11 fractures were subtrochanteric (type C), 6 complex diaphyseal and the remaining 3 were supracondylar (2 type C3 and 1 type A3); 3 fractures were open (type I, II, IIIA). Subtrochanteric fractures were treated with either 95 degrees dynamic condylar screw (DCS; 5 fractures) or with 135 degrees dynamic hip screw (DHS; 6 fractures). Autocompression plates (ACP) implants were chosen for diaphyseal fractures in 4 fractures, and a limited contact dynamic compression plate (LC/DCP) implant in 2. The 3 supracondylar fractures were treated with a 95 degrees DCS implant (1 fracture) and the Condylar Buttress Plate (2 fractures). 11 fractures were bone grafted. There were no immediate postoperative complications. All fractures united on an average of 5 months, irrespective of use of bone grafts. Late complications consisted of mild knee stiffness (4 patients) and 1-2 cm shortening (4 patients).

Collaboration


Dive into the Theodore A. Xenakis's collaboration.

Top Co-Authors

Avatar

Panayotis N. Soucacos

National and Kapodistrian University of Athens

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge