Yapici, Furkan

BACKGROUND: "Internal-locking" concepts-deployable talons/claws and tanged anchors, winged/wedge-wing head elements, blade-expandable and wedge-locked distal modules, inside-to-out internal distal locking pins (endopins), and shape-memory (nitinol) wings-aim to streamline intramedullary (IM) fixation by reducing reliance on freehand distal interlocking screws while maintaining stability. METHODS: A scoping, mechanics-informed review was conducted using PubMed/MEDLINE, Scopus, Web of Science, and Google Scholar (January 1980-October 2025; last search October 25, 2025). Studies evaluating intramedullary systems with internal-locking mechanisms for the humeral shaft/diaphysis, hip (intertrochanteric, basicervical, or subtrochanteric), femoral shaft/distal femur, tibia, fibula, clavicle, and selected pelvic/foot indications were eligible. Bench/FEA, cadaveric, clinical (comparative and single-arm), technique, and health-economic reports were included. For human clinical studies, English-language full texts were eligible; during revision, non-English full texts with an English abstract and extractable outcome data were re-evaluated. Screening was performed by a single reviewer, and data were charted by anatomic pattern, key technique covariates (reduction quality, central-inferior head position, tip-apex distance [TAD]), outcomes, and complications. Sixty-three sources of evidence met eligibility criteria and were charted; details are compiled in Supplementary Table S1 (Master Evidence Table). The remaining 10 references are background/methodological or definitional citations-for example, foundational work informing technique covariates such as tip-apex distance (TAD) and calcar-referenced metrics (e.g., Calcar-TAD)-and therefore are not listed or appraised in the supplementary evidence tables. RESULTS: For the humeral shaft, internal distal-locking strategies reduce the distal-targeting burden of antegrade nailing and may shorten surgery while avoiding an additional distal incision, but outcomes remain strongly technique-dependent. Historical Seidel data and more recent humeral internal-locking series suggest that the main risks are rotational instability, technical locking failure, proximal hardware-related symptoms, and shoulder morbidity rather than the distal mechanism alone. Bench and cadaveric studies indicate that inferior subchondral deployment of talons increases torsional resistance (~ 2-3×) and interfragmentary compression (~ 2×) versus retracted configurations, providing a plausible basis for reduced lag-element sliding when TAD is 15-25 mm and the head element is central-inferior. Finite-element models suggest that wedge-locked constructs can approximate screw-locked axial/torsional stiffness when deployment torque and friction are adequate, albeit with stress concentrations near the locking windows. Clinically, in geriatric intertrochanteric fractures, union and functional outcomes are generally similar among talon-equipped, helical-blade, and dual-screw cephalomedullary nails when reduction/TAD are optimized; internal-locking designs are often associated with shorter operative and fluoroscopy times, and distal talon locking has been reported to be associated with lower cutout in unstable patterns. In femoral/tibial shafts, internal distal locking shortens procedures and radiation without consistent union penalties, although simple diaphyseal patterns distal to the isthmus show a greater risk of axial shortening/malrotation without adjuncts. In the fibula and clavicle, modern intramedullary systems achieve high union rates (~ 98-100%) with low wound morbidity; in benchtop/synthetic models, talon screws have reproduced plating-like axial stiffness while remaining torsionally inferior. Early health-economic signals suggest the potential cost-effectiveness of talon-locking constructs. CONCLUSIONS: Across indications, operative technique remains the dominant determinant of outcome; thoughtfully selected internal locking mechanisms can deliver efficiency and soft tissue advantages without compromising stability when fundamentals (reduction quality, central-inferior head position, TAD 15-25 mm) are respected. A practical taxonomy and decision framework are proposed, along with priorities for pattern-stratified comparative trials and engineering refinements.

Kalyenci, Ahmet Sinan; Dogan, Ibrahim; Tekin, Saltuk Bugra; Ozmen, Zana; Senel, Ahmet; Ozturkmen, Yusuf

Background: The success of primary total hip arthroplasty (THA) in patiens with primary osteoarthritis (OA) of the hip is significantly influenced by stem osseointegration, migration and implantation. Additionally, the bone mineral density (BMD) of the proximal femur, the femoral morphology and stem design play important roles in these outcomes. This study aimed to evaluate the effect of BMD on subsidence who underwent primary cementless THA with a fit-and-fill stem design for primary OA of the hip, assuming that subsidence is not influenced by BMD. Methods: This prospective study included 72 hips from 67 patients who underwent primary cementless THA for OA between May 2019 and March 2022. Two patients were excluded due to intraoperative complications, and the final analysis was conducted on 70 hips. Patients were grouped according to preoperative BMD and proximal femur anatomy based on Dorr classification. Harris Hip Score (HHS), radiological subsidence and Engh score values ​​were used for postoperative clinical evaluation. Results: The mean age was 65.99 ± 8.10 years (range 52 to 83 years). The mean follow-up was 24.6 ± 5.8 months (range, 12 to 34 months). Amongst 70 OA of the hip cases, 22 (31.43%) were Dorr type A, 44 (62.86%) type B, and 4 (5.71%) type C. Forty-three patients (61.43%) had normal BMD, while 27 patients (38.57%) were osteopenic or osteoporotic. The mean axial migration at the latest follow-up was 1.04 ± 0.69 mm (range 0 to 3.1 mm). Total Engh score was 22.89 ± 3.28 (range 14 to 27), and in terms of stabilization bone ingrowth was seen in all of the femoral stems. There was no statistically significant effect of femoral T-score levels (p = 0.853) or femoral morphologies (p = 0.763) on femoral stem subsidence. Conclusions: No statistically significant differences were observed in clinical or radiological outcomes between patients with normal and low BMD. These findings suggest that early stem migration and osseointegration are more closely related to initial mechanical stability than to BMD. Cementless femoral stems can therefore be considered reliable across different bone qualities, offering an innovative perspective that challenges the conventional emphasis on bone density in implant selection.

Erdogan, Furkan; Yildirim, Abdurrahman Murat; Cengiz, Tolgahan; Yurtbay, Alparslan; Sezgin, Hicabi; Dabak, Nevzat

ObjectivesOur study aims to investigate the factors associated with survival in patients with skeletal metastases of renal cell carcinoma and to outline the principles of managing patients with skeletal metastases using a multidisciplinary approach.Materials and methodsWe retrospectively reviewed 42 patients with clear cell metastatic renal cell carcinoma (mRCC) and bone metastases treated between 2005 and 2022. Demographics, tumor characteristics, metastasis patterns, surgical interventions, and systemic treatments were recorded. Survival outcomes were analyzed using the Kaplan-Meier method and the Cox proportional hazards model. Factors such as MSKCC and IMDC risk scores, the number and location of metastases, and treatment modalities were evaluated for their prognostic impact.ResultsForty-two patients with a mean age of 58.4 years and a mean follow-up period of 28.4 months were included in the study. The 1-, 2-, and 5-year overall survival (OS) rates were 73.7%, 44.2%, and 13.7%, respectively. Solitary metastases (5-year OS 80%) and complete metastasectomy (5-year OS 20.1%) were associated with significantly improved survival. Diffuse metastases (HR 22.8; p = 0.006) and oligometastases (HR 7.7; p = 0.044) were associated with higher mortality compared to solitary lesions. Neither MSKCC nor IMDC scores were independently predictive of OS in multivariate analysis. Systemic therapies, including tyrosine kinase inhibitors (TKIs), mTOR inhibitors, antiresorptive agents, and radiotherapy, did not significantly impact survival outcomes.ConclusionThis study emphasizes that metastatic burden and achieving complete metastasectomy are the most critical factors for prolonged survival in metastatic renal cell carcinoma (mRCC) with bone involvement. Systemic therapies alone provide limited benefit, highlighting the need for individualized, multidisciplinary treatment strategies. Prospective studies are warranted to refine prognostic models and optimize care for this challenging patient group.

Gür, Volkan; Yapici, Furkan; Subasi, Izzet Ozay; Gökgöz, Mehmet Burak; Tanoglu, Oguzhan; Koçkara, Nizamettin; Tandogan, Nevzat Reha

Background Genu valgum is considered to be a risk factor for patellar instability. Correction of valgus alone or combined with a tibial tuberosity medialization has been described. However, changes occurring in the tibial tuberosity-trochlear groove (TT-TG) distance after a lateral distal femoral opening wedge osteotomy (LDF-OWO) are not known.Purpose This study aimed to define changes in TT-TG distance with increasing amounts of valgus correction after LDF-OWO.Methods Three-Dimensional Computed Tomography (3D-CT) scans of six patients (two females and four males) aged between 19 and 35 years with genu valgum and patellar instability were analyzed. 3D models of femoral, tibial, and patellar bones were created with the advanced segment option of Mimics 21 (R) software. An oblique lateral opening wedge osteotomy of the distal femur was simulated in 2-degree increments up to 12 degrees of varus opening. Change in TT-TG distance was measured in mm on 3D models of the knee.Results Compared to baseline without osteotomy, the TT-TG distance decreased significantly (p < 0.05) for all corrections from 2 to 12 degrees in 2 degrees steps. The TT-TG distance decreased by an average of 1.7 mm for every 2 degrees of varus opening.Conclusion Lateral opening wedge distal femoral osteotomy causes a decrease in TT-TG distance. The surgeon should be aware of the magnitude of this change (1.7 mm decrease for every 2 degrees increment of valgus opening).