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Featured researches published by Gokcer Uzer.


Journal of Shoulder and Elbow Surgery | 2017

Efficacy of bone marrow-stimulating technique in rotator cuff repair

Kerem Bilsel; Fatih Yildiz; Mehmet Kapicioglu; Gokcer Uzer; Mehmet Elmadag; Anil Pulatkan; Mukaddes Esrefoglu; Ergun Bozdag; Giuseppe Milano

BACKGROUND This study used a chronic rotator cuff (RC) tear model to investigate the effect of microfracture as a bone marrow-stimulating (BMS) technique for RC healing. METHODS A chronic retracted RC tendon tear model was created bilaterally in the subscapularis tendons of 20 New Zealand rabbits. The tendons were repaired after 8 weeks using a single-row configuration. Tendons in the right shoulder were repaired in standard fashion (control group). Microfractures were performed in the left shoulders before repair (microfracture group). The animals were euthanized 8 and 16 weeks after repair. The repaired tendons were tested biomechanically for their ultimate failure load, linear stiffness, and elongation at failure. Gross and histologic evaluations of the tendon-to-bone healing were evaluated. RESULTS Macroscopically, subscapularis tendons were attached on the lesser tuberosity. In the microfracture group, collagen fibers were organized in relatively thicker bundles. The mean ultimate failure load of the microfracture group was significantly greater at 8 weeks (148.4 ± 31 N vs. 101.4 ± 26 N, respectively; P = .011) and 16 weeks (155 ± 30 N vs. 114.9 ± 25 N, respectively; P = .017) after repair. There were no significant differences between the groups for linear stiffness at 8 weeks (15.9 ± 2.7 N/mm vs. 15.8 ± 1.3 N/mm, respectively; P = .798) and 16 weeks (16.9 ± 4.3 N/mm vs. 17.1 ± 3.6 N/mm, respectively, P = .848) and elongation at failure at 8 weeks (4.7 ± 1.1 mm vs. 4.7 ± 1.3 mm, respectively; P = .848) and 16 weels (4.8 ± 1.5 mm vs. 4.9 ± 0.9 mm, respectively; P = .749). CONCLUSION The microfracture on the tuberosity of the repaired chronic rotator cuff tear promoted dynamic tendon healing with significantly increased ultimate force to failure and with thicker collagen bundles and more fibrocartilage histologically at 8 weeks.


Journal of Shoulder and Elbow Surgery | 2017

Does grafting of the tuberosities improve the functional outcomes of proximal humeral fractures treated with reverse shoulder arthroplasty

Gokcer Uzer; Fatih Yildiz; Suat Batar; Ruwais Binlaksar; Mehmet Elmadag; Gamze Kuş; Kerem Bilsel

BACKGROUND Functional outcomes of reverse total shoulder arthroplasty (rTSA) can be improved by fixation of the tuberosities. This study compares clinical and radiologic results of patients with comminuted proximal humeral fractures treated with rTSA, with and without autologous grafting. METHODS Thirty-three patients with proximal humeral fractures were treated with rTSA and tuberosity fixation. In 18 patients (group I; mean age, 75 years), tuberosity fixation was augmented with autografting; in 15 patients (group II; mean age, 71 years), graft augmentation was not used. The mean follow-up was 16.7 (range, 12-24) months in group I and 16.8 (range, 12-25) months in group II. RESULTS Radiologic tuberosity union was achieved in 14 of 18 (77.8%) patients who underwent autograft augmentation and in 6 of 15 (40.0%) patients treated without autografting. The mean American Shoulder and Elbow Surgeons (ASES) score was 69.6 ± 13.0 in group I and 51.0 ± 20.0 in group II. The mean Disabilities of the Arm, Shoulder, and Hand (DASH) score was 31.9 ± 24.0 in group I and 58.2 ± 24.6 in group II. A significant difference was detected between groups for ASES and DASH scores. Among shoulder range of motion measures, only forward flexion differed significantly between groups I and II (124° ± 23° vs. 98° ± 30°, respectively). External rotation muscle strength was significantly higher in group I (3.36 ± 1.46 kg) than in group II (2.39 ± 2.00 kg). CONCLUSION In the treatment of complex proximal humeral fractures in elderly patients by rTSA, cancellous block autograft augmentation can increase the rate of tuberosity union and improve functional outcomes.


Acta Orthopaedica et Traumatologica Turcica | 2016

Safety of modified Stoppa approach for Ganz periacetabular osteotomy: A preliminary cadaveric study

Mehmet Elmadag; Gokcer Uzer; Fatih Yildiz; Hasan Huseyin Ceylan; Mehmet Ali Acar

Objective The aim of this cadaveric study was to investigate the efficacy of the modified Stoppa approach in Ganz periacetabular osteotomy (PAO). Methods The Ganz PAO was performed on 10 hemipelvises with normal hips, from 5 cadavers using the modified Stoppa approach through the Pfannenstiel incision. All of the osteotomies were performed under fluoroscopic control and direct visualizing the osteotomy site from the same incision. After the osteotomy, the acetabulum was medialized and redirected anterolaterally, and fixed with 2 screws. The neurovascular structures and the joints were examined by dissecting the soft tissues after fixation of the osteotomies. Outcome parameters were center-edge (CE) angle, the distances between the osteotomy and anterior superior iliac spine (ASIS), and between the osteotomy and the sciatic notch, neurovascular and joint penetrations. Results After the osteotomy, the mean CE angle was improved from 19.8° to 25.2°, mean distance between the osteotomy and ASIS was 3.1 cm, and the mean distance between the osteotomy and the sciatic notch was 10.2 mm. The neurovascular structures and the joints were examined by dissecting the soft tissues after fixation of the osteotomies. No damage to the joint, surrounding arteries, veins or nerves was detected in any of the cadavers. Conclusions Bilateral dysplastic hips can be treated with a 10 cm, cosmetically more acceptable incision in the same session using this approach. Quadrilateral surface of the acetabulum can be directly seen using this approach and the osteotomy can be safely performed.


Turkish journal of trauma & emergency surgery | 2015

Comparison of two types of proximal femoral hails in the treatment of intertrochanteric femur fractures.

Gokcer Uzer; Nuh Mehmet Elmadağ; Fatih Yildiz; Kerem Bilsel; Tunay Erden; Huseyin Toprak

BACKGROUND Hip nailing is frequently used to treat unstable intertrochanteric femoral fractures (ITF) in elderly patients. In this retrospective study, we compared the functional and radiological results, and the complications, of patients treated using proximal femoral nails (PFN) with an integrated, interlocking, compression lag screw, or two separate lag screws, which allow linear compression at the fracture site. METHODS A total of one hundred and eighteen patients were operated on for AO/OTA 31-A2 ITF between May 2010 and April 2012, and eighty-two of these patients, for whom sufficient follow-up data and documentation were available, were included into the study. PFNs with interlocking, integrated lag screws (Group I) were used in forty-four patients, and PFNs with two separate lag screws (Group II) in thirty-eight. Outcome parameters were the extent of varus collapse and leg length discrepancy on radiographs, and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Harris hip scores (HHS) as functional results. RESULTS Mean follow-up duration was 20 months (range, 12-36 months); fractures healed in all patients. Mean varus collapse values were 2.03±5.68° and 5.21±5.27° (p=0.01), Harris hip scores 73.2±11.65 and 74.72±11.15 (p=0.54), and WOMAC scores 70.78±11.41 and 71.78±11.19 (p=0.69) in Groups I and II, respectively. No difference was detected between the groups in terms of outcome parameters or complication rate. CONCLUSION In the treatment of ITF, PFNs with an integrated, interlocking, compression lag screw, or two separate lag screws did not differ in terms of functional and radiological results or complication rate.


Case reports in orthopedics | 2013

Pediatric Transepiphyseal Seperation and Dislocation of the Femoral Head

Mehmet Elmadag; Hasan Huseyin Ceylan; Kerem Bilsel; Gokcer Uzer; Mehmet Ali Acar

Pediatric hip fractures and dislocations are rare in practice and are related to high-energy trauma. The incidence of postoperative avascular necrosis is increasing, especially in the case of transepiphyseal fractures. Surgery is the most common form of treatment, and its timing is important for prognosis of the fracture. Patients and their families should be informed about the possibility of avascular necrosis and further complications related to the fracture.


Orthopaedic Journal of Sports Medicine | 2017

Increasing number of small hole diameter microfracture compared with traditional microfracture in same size cartilage defects and effect of HA based aselluler scaffold. An animal study

Gokcer Uzer; Nuh Mehmet Elmadağ; Fatih Yildiz; Yunus Güzel; Olgu Enis Tok

Purpose: The purpose of this study is small hole microfracure method comparing with traditional microfracture method and investigation of effect of HA based acellular matrix scaffold on microfracture area. Materials-Methods: 21 Twenty-one New Zealand white rabbits were used for the in vitro portion of this study, bilateral knee joint from the same rabbit were same technic. An articular cartilage defect was established in the femoral trochlear groove about 5 mm. Control group was established alone microfracture (MF). 6 groups were formed in this study and each group has 3 rabbits and their six knees. In 3 groups were applied different number of small diameter hole microfracture (4,5,6 small holes microfracture respectively)and the other 3 groups were applied different number of small diameter hole microfracture (4,5,6 small holes micro fracture respectively added HA based acellular matrix scaffold in the same size ostechondral lesion. The regenerated tissues were harvested for gross morphology, histology at 12 weeks postoperatively. Results: Cartilage were regenerated, maintaining a constant thickness of cartilage. MF group has worse Wakitani scores than 6 small diameter holes mıcrofracture groups(group 6 and group 7) in either parameter of the score. (p=0,043, p=0,016) Matrix addition did not contribute to healing. (p=1,000) Conclusions: Increasing number of the small diameter holes microfracture (minimum %15 of defect size) improves cartilage repair compared with traditional MF in the same size ostechondral lesion. Also small diameter holes microfracture combined with HA-based AM implantation didn’t result in improved quality of the regenerated cartilage tissue.


Orthopaedic Journal of Sports Medicine | 2017

Efficacy of Bone Marrow-Stimulating Technique in Rotator Cuff Repair

İsmail Kerem Bilsel; Fatih Yildiz; Mehmet Kapicioglu; Gokcer Uzer; Mehmet Elmadag; Mehmet Anil Pulatkan; Mukaddes Esrefoglu; Ergun Bozdag; Guiseppe Milano

Background: This study investigates the effect of microfracture as a bone marrow-stimulating(BMS) technique on rotatory cuff(RC) healing using a chronic RC tear model. Methods: Chronic retracted RC tendon tear model was created in the subscapularis(SSC) tendons of 20 New Zealand rabbits, bilaterally. The tendons were repaired after eight weeks using a single-row configuration with suture anchors. In right shoulders, tendons were repaired in a standard fashion(control group). In left shoulders, microfractures were performed on the SSC footprint before repair(microfracture group). The animals were sacrificed 8 and 16 weeks after repair. The repaired tendons were tested biomechanically for their ultimate failure load, linear stiffness and elongation at failure. Gross and histological evaluation of the tendon-to-bone healing was evaluated. Results: In every sample, the SSC tendon was attached to its footprint on the lesser tuberosity. In microfracture group, collagen fibers were organized in relatively ticker bundles at both time intervals. The mean ultimate failure load of microfracture was significantly greater than that of control group at 8 (148.4+31 N vs. 101.4+26 N; p=0.011) and 16 (155+30 N vs. 114.9+25 N; p=0.017) weeks after repair, respectively. There were no significant differences between the two groups at each time interval for linear stiffness (15.9+2.7N/mm vs. 15.8+1.3N/mm, p=0.798 and 16.9+4.3N/mm vs. 17.1+3.6N/mm, p=0.848, respectively) and elongation at failure (4.7+1.1 mm vs. 4.7+1.3 mm, p=0.848 and 4.8+1.5 mm vs. 4.9+0.9 mm, p=0.749, respectively). Conclusions: The BMS technique of microfracture on the tuberosity of the repaired chronic rotator cuff tear promotes the dynamic tendon healing with significant ultimate force to failure and apparent microscopic findings.


Journal of Shoulder and Elbow Surgery | 2017

Biomechanical comparison of three different plate configurations for comminuted clavicle midshaft fracture fixation

Gokcer Uzer; Fatih Yildiz; Suat Batar; Ergun Bozdag; Hacer Kuduz; Kerem Bilsel

BACKGROUND The aim of this study was to compare the fixation rigidity of anterior, anterosuperior, and superior plates in the treatment of comminuted midshaft clavicle fractures. METHODS Six-hole titanium alloy plates were produced according to anatomic features of fourth-generation artificial clavicle models for anterior (group I; n = 14), anterosuperior (group II; n = 14), and superior (group III; n = 14) fixation. After plate fixation, 5-mm segments were resected from the middle third of each clavicle to create comminuted fracture models. Half the models from each group were tested under rotational forces; the other half were tested under 3-point bending forces. Failure modes, stiffness values, and failure loads were recorded. RESULTS All models fractured at the level of the distalmost screw during the failure torque, whereas several failure modes were observed in 3-point bending tests. The mean stiffness values of groups I to III were 636 ± 78, 767 ± 72, and 745 ± 214 N ∙ mm/deg (P = .171), respectively, for the torsional tests and 38 ± 5, 20 ± 3, and 13 ± 2 N/mm, respectively, for the bending tests (P < .001 for group I vs. groups II and III; P = .015 for group II vs. group III). The mean failure torque values of groups I to III were 8248 ± 2325, 12,638 ± 1749, and 10,643 ± 1838 N ∙ mm (P = .02 for group I vs. II), respectively, and the mean failure loads were 409 ± 81, 360 ± 122, and 271 ± 87 N, respectively (P = .108). CONCLUSIONS In the surgical treatment of comminuted midshaft clavicle fractures, the fixation strength of anterosuperior plating was greater than that of anterior plating under rotational forces and similar to that of superior plating.


Bezmialem Science | 2017

Comparison Between Y- and S-Shaped Incisions for Open Reduction and Hook-Plate Fixation of the Mallet Finger

Gokcer Uzer; Fatih Yildiz; Mehmet Kapicioglu; Mehmet Elmadag; Deniz Kara; Kerem Bilsel

Objective: This study evaluates the results of open reduction and hook-plate fixation in the treatment of osseous mallet finger and compares Sand Y-shaped incisions used for the approach. Methods: Twenty-eight patients treated for osseous mallet finger using open reduction and hook-plate fixation were divided into two groups according to their incisions types (group I: S-shaped, n=18; and group II: Y-shaped, n=10). Functional results at the first year of follow-up and complications were evaluated. Results: All fractures healed. In group I, all patients had excellent results; in group II, nine patients had excellent results, and one patient had fair results. The numbers of complications were two in group I and six in group II. Conclusion: Hook-plate fixation is a successful treatment method for osseous mallet finger. The rate of complications can be decreased using an “S-shaped” incision with this technique. However, patients should be informed about possible skin problems and nail deformities.


Bezmialem Science | 2017

Is hyperflexion possible with the solitary use of high-flexion insert in knee replacement preserving the posterior cruciate ligament? (Mid-term results)

Vahit Emre Özden; Goksel Dikmen; Gokcer Uzer; Ismail Remzi Tozun

Amaç: Hiperfleksiyona izin veren tasarımlı total diz protezi uyguladığımız hastalarımızın erken-orta dönem sonuçlarını değerlendirmek ve özellikle fleksiyon açıklığı üzerine etkili faktörleri belirlemek. Yöntemler: Hiperflex arka çapraz bağ koruyan tipi diz protezi uyguladığımız 95 hastanın 150 dizi değerlendirmeye alındı. Hastalar ortalama 8.5 yıl (3.5-11 yıl) takip edildiler. Diz eklemleri ameliyat öncesinde ve son kontrolde Diz Cemiyeti Puanlama Sistemi ile değerlendirildi ve hareket açıklıkları kaydedildi. Komponent sağkalımı değerlendirildi. Ameliyat sonrasında yüksek fleksiyon derecesine (>130) ulaşabilmek için ameliyat öncesinde olması gereken fleksiyon açıklığı ise ROC eğrisi (receiver-operating characteristic) analizi ile araştırıldı. Bulgular: Ameliyat öncesi ortalama diz skoru 49.1±12.0 puan, fonksiyon skoru 48.9±14.1 puan ve fleksiyon açısı 119.3±18.9 derece olarak bulundu. Son kontrollerde aynı değerler sırasıyla 92.9±8.2 (p<0.0001), 90.7±10.6 (p<0.0001) ve 128.0±11.5 derece (p<0.0001) seviyesine yükseldi. Yetmiş (47%) dizde fleksiyon açıklığında bir artış sağlanamazken, bu hastalardan 27’sinde (18%) dizde fleksiyon değerinde azalma oldu. Ameliyat öncesi ve sonrası fleksiyon açıklıkları arasında orta seviyede korelasyon tespit edildi (r=0.623, p<0.0001). Bir adet (0.6%) ara yüzey revizyonu erken dönem enfeksiyon nedeni ile yapıldı. Aseptik gevşeme gözlenmedi. ROC eğrisi analizi ameliyat öncesinde 115° ve üzerinde fleksiyonu olan dizlerde ameliyat sonrasında 130° ve üzerinde hiperfleksiyon beklenebileceğini tespit edildi. Sonuç: Çalışmamızın sonucunda ameliyat sonrası fleksiyon derecesi, ameliyat öncesi fleksiyon derecesi ile ilişkili olarak bulunmuştur. Bu çalışma ile sadece yüksek fleksiyona izin veren ara yüzey kullanarak yüksek fleksiyon dereceleri elde edilemeyeceği, ameliyat öncesi fleksiyon açıklığının hiperfleksiyona ulaşmanın bu tip tasarımda bile önemli bir faktör olduğu sonucuna ulaşıldı. Anahtar Sözcükler: Bağkoruyan arayüzey, hiperfleksiyon, diz artroplastisi ABSTRACT

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Ergun Bozdag

Istanbul Technical University

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Ibrahim Tuncay

Yüzüncü Yıl University

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Hacer Kuduz

Istanbul Technical University

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