< Back Dr. Serkan BAYRAM Endoprosthesis Endoprosthetic reconstruction is a cornerstone technique in musculoskeletal oncology, allowing immediate restoration of skeletal continuity and early mobilization after wide tumor resection. Modern modular megaprostheses, made of titanium or cobalt-chromium alloys, are designed for durability, functional recovery, and ease of revision. They are primarily indicated for periarticular or diaphyseal bone loss following tumor excision, failed fixation, or pathological fractures. Cemented fixation ensures immediate stability, while press-fit and porous-coated designs promote biological integration. Despite excellent limb salvage rates (>90%), complications such as infection, aseptic loosening, and mechanical failure remain challenges. Advances including silver-coated implants, expandable pediatric prostheses, and improved soft-tissue reattachment techniques continue to enhance long-term outcomes and quality of life for oncology patients. Definition An endoprosthesis is a modular metallic implant used to reconstruct bone and joint defects following wide resection of primary or metastatic musculoskeletal tumors. The aim is to achieve immediate structural stability , preserve limb function, and allow early mobilization, particularly in cases where biological reconstruction (allograft or autograft) is not feasible. Indications Segmental bone loss after tumor resection, particularly in the proximal humerus , distal femur , and proximal tibia . Periarticular destruction due to primary bone sarcomas (e.g., osteosarcoma, Ewing sarcoma) or metastatic disease. Reconstruction after pathological fractures or failed fixation in oncologic bone. Salvage after infection or mechanical failure of previous reconstruction. Design and Components Modern tumor prostheses are modular megaprostheses made from titanium or cobalt-chromium alloys, often with: Cemented or press-fit stems for fixation into the remaining diaphysis. Rotating hinge joints (knee and elbow) to reduce torque and wear. Porous-coated or hydroxyapatite collars to promote soft-tissue and bone integration. Expandable designs for skeletally immature patients, allowing non-invasive limb-length adjustment. Cemented fixation offers immediate stability, while cementless (press-fit) fixation supports long-term biological fixation and easier revision. Surgical Principles Wide oncologic margins are mandatory to minimize local recurrence. Preservation of neurovascular structures and soft-tissue coverage is essential. Stable fixation and restoration of limb length should be achieved intraoperatively. Reconstruction of muscle attachments (especially in proximal humerus and tibia) improves functional outcome. Prophylactic antibiotic cement or silver-coated implants are used to reduce infection risk in high-risk cases. Advantages Immediate load-bearing capability. Shorter operative time compared to biological reconstructions. Predictable early function and pain relief. Can be revised modularly if components wear or fracture. Complications Infection (5–15%); more common in immunocompromised or irradiated patients. Mechanical failure (loosening, stem breakage). Aseptic loosening due to stress shielding. Periprosthetic fracture and soft-tissue failure (e.g., extensor mechanism insufficiency). Outcomes and Prognosis Endoprosthetic reconstructions provide excellent pain relief and limb salvage rates exceeding 90% in modern series. Five-year implant survival is around 70–80% , depending on site and indication. Long-term durability is enhanced by improved modular designs, better fixation strategies, and multidisciplinary care. References Rizzo SE, Kenan S. Pathologic Fractures. StatPearls Publishing, 2025. Fields RC et al. Management of Pathological Fractures: Current Consensus. Knee Surg Sports Traumatol Arthrosc , 2024. Boussouar S et al. Tailored Approach for Appendicular Pathologic Fractures from Metastatic Bone Disease. Cancers (Basel) , 2022. Jeys L, Grimer R. Endoprosthetic Reconstruction After Tumor Resection. J Bone Joint Surg Br , 2019. Henderson ER et al. Failure Mode Classification for Tumor Endoprostheses: An International Consensus. Clin Orthop Relat Res , 2017. Quick Facts Feature Details Purpose Reconstruction of segmental bone or joint defects after tumor resection Main Indications Primary or metastatic bone tumors, failed fixation, post-infection salvage Common Sites Distal femur, proximal tibia, proximal humerus, proximal femur Design Type Modular or custom-made megaprostheses (cemented or press-fit fixation) Expandable Prostheses Used in skeletally immature patients to allow limb-length adjustment Key Materials Titanium, cobalt-chromium alloys, silver-coated or hydroxyapatite collars Advantages Immediate stability, early mobilization, predictable limb function Common Complications Infection (5–15%), aseptic loosening, mechanical failure, periprosthetic fracture Functional Outcome Limb salvage rate >90%; 5-year implant survival 70–80% Preferred in Large bone defects or periarticular resections where biological grafting is not feasible Previous Next

< Back Dr. Ahmet Müçteba YILDIRIM Enchondroma Overview • Enchondroma is a benign hyaline cartilage tumor, accounting for 20-25% of benign bone tumors. • It arises from residual cartilage cells that fail to undergo necrosis after physeal growth. • Can be solitary or multiple (Ollier’s disease, Maffucci syndrome). Clinical Presentation Often asymptomatic, detected incidentally (except in hand lesions). Hand enchondromas: Pain due to bone expansion, cortical thinning, or microfractures. Long bone enchondromas with pain: Rule out first intra-articular pathologies, atypical cartilage tumor or chondrosarcoma Radiographic Features Enchondromas are typically incidental, well-defined intramedullary lesions smaller than 5 cm. They appear lytic with a narrow transition zone and smooth margins. Characteristic “rings-and-arcs” chondroid calcifications may be present, though lesions in the hands and feet often remain purely lytic. Mild endosteal scalloping or slight expansion can occur, but cortical breakthrough, periosteal reaction, or soft-tissue mass should not be seen. These lesions usually arise in the metaphysis, reflecting their origin from the growth plate; an epiphyseal cartilaginous lesion should raise concern for chondrosarcoma. Plain Radiograph and CT Enchondromas usually present as small (<5 cm), intramedullary, lytic lesions with non-aggressive characteristics such as: · well-defined margins and a narrow transition zone · possible “rings and arcs” calcification reflecting a chondroid matrix · in the hands and feet, frequently purely lytic without visible matrix mineralization · occasional mild expansion and endosteal scalloping · absence of cortical breakthrough unless secondary to a pathological fracture MRI Findings MRI best demonstrates lesion extent and confirms the intramedullary, lobulated nature of enchondromas. T1-weighted: intermediate to low signal with internal low-signal foci corresponding to calcified cartilage. T2-weighted: sharply defined high signal due to water-rich cartilage, with “rings-and-arcs” low-signal areas. Post-contrast (T1 + Gd): peripheral or septal enhancement following the lobulated contours. No surrounding bone-marrow or soft-tissue edema is expected. However, enhancement patterns may occasionally resemble those of low-grade chondrosarcoma, so correlation with clinical and radiographic features is essential. Associated Syndromes Ollier’s disease: Multiple enchondromas, unilateral, 20-50% malignant transformation risk. Lesions are generally unilateral. Short stature, limb length discrepancy, and angular deformities in bones and joints are commonly seen. Maffucci syndrome: Enchondromas + soft tissue hemangiomas; higher malignancy risk than Ollier’s. Due to phleboliths, hemangiomas are also detected on X-rays. Common Sites Hands (40-65%): Proximal phalanges > metacarpals > middle phalanges. Long bones: Femur, humerus, tibia (metaphyseal). Rare in carpal/tarsal bones or distal phalanges. Imaging Features X-ray: Hands: Lytic, sclerotic rim, bone expansion, cortical thinning, calcification is not usually seen. Long bones: Metaphyseal, indistinct margins, endosteal scalloping, matrix calcification. CT: Evaluates calcification and cortical integrity. MRI: Assesses soft tissue extension, peritumoral edema, contrast enhancement (for differential diagnosis) and fat entrapment. PET-CT: Useful for enchondromatosis/pelvic lesions Biopsy Not routine; reserved for atypical features (e.g., pain, growth, or imaging suspicious for chondrosarcoma). Target less calcified, fat entrapment and heterogeneous areas on MRI. Biopsy tract should align with potential surgical incision. Treatment Asymptomatic, small (<4 cm), stable lesions: Annual monitoring.(BACTIP Protocole* : Birmingham Atypical Cartilage Tumor Imaging Protocol) Surgical indications: Pain, growth on follow-up, or pathologic fracture risk. Techniques: Intralesional curettage + adjuvant + bone-filler (PMMA/graft) ± fixation (fracture risk in lower extremities). Hand lesions: Curettage alone/ Curettage and bone filler (PMMA/Graft) Differential Diagnosis Atypical Cartilage Tumor (ACT): WHO 2020 reclassified grade I chondrosarcomas in extremities as ACT (no metastasis risk but can recur). Suspect if pain, size >4 cm, generalized endosteal scalloping. Chondrosarcoma: Cortical destruction, soft tissue involvement, axial skeleton location. Type Tumor Length Endosteal Scalloping Management 1a <4 cm None Discharge 1b <4 cm Focal Follow-up in 3 years; refer to oncology or discharge based on changes 1c <4 cm Generalized Immediate oncology referral 2a ≥4 cm None Follow-up in 3 years; refer to oncology or discharge based on changes 2b ≥4 cm Focal Follow-up at 1 & 3 years; refer to oncology or discharge 2c ≥4 cm Generalized Immediate oncology referral 3 any size Aggressive features Immediate oncology referral The Birmingham Atypical Cartilage Tumor Imaging Protocol (BACTIB) classification CT and MRI images of the distal femur demonstrate a well-defined intramedullary chondroid lesion with characteristic rings-and-arcs calcifications on CT, consistent with enchondral matrix mineralization. On MRI, the lesion shows intermediate to low signal on T1-weighted and high signal on T2-weighted sequences with internal low-signal foci corresponding to calcified cartilage. There is no cortical destruction, periosteal reaction, or soft-tissue extension, supporting the diagnosis of a benign enchondroma. Previous Next

< Back Radiographic Evaluation radiographic-evaluation-foot-ankle Previous Next

< Back Pediatric Trauma C A pediatric-trauma Previous Next

< Back Damage Control S SS damage-control Previous Next

< Back Hip Fractures B S hip-fractures Previous Next

< Back Dr. Ahmet Müçteba Yıldırım Staging Systems (Enneking, AJCC) Staging plays a crucial role in treatment planning and prognosis estimation for primary bone and soft tissue tumours. The two main systems used in orthopaedic oncology are: Enneking Staging System (commonly used in surgical planning) AJCC TNM Staging System (widely used in oncology) 1. Enneking Staging – Bone Sarcomas This system includes: Grade (G): Histological aggressiveness T (Tumour extension): Local vs extracompartmental M (Metastasis): Distant spread 2. Grade Classification (Enneking) G1 (Low Grade): Mild atypia, mitosis <1/10 HPF Examples: ACT, parosteal osteosarcoma G2 (High Grade): Distinct atypia, mitosis 1–2/10 HPF Examples: Classic osteosarcoma, Grade 2 chondrosarcoma G3 (Anaplastic/Dedifferentiated): Marked atypia, mitosis >2/10 HPF Examples: Ewing sarcoma, undifferentiated chondrosarcoma 3. T & M Definitions (Enneking) T1: Tumour within compartment T2: Extension to soft tissue, skip metastasis, or pelvic involvement M1: Presence of distant metastasis 4. Enneking Stage Summary Table Stage IA Grade 1 (low grade) Tumour confined within the bone (T1) No metastasis (M0) Stage IB Grade 1 Tumour has extended beyond the compartment (T2) No metastasis (M0) Stage IIA Grade 2 or 3 (high grade) Tumour confined (T1) No metastasis (M0) Stage IIB Grade 2 or 3 Tumour has spread beyond compartment (T2) No metastasis (M0) Stage III Any grade Any tumour extent Distant metastasis present (M1) 5. AJCC Staging – Bone Tumours (8th Edition) More commonly used by oncologists. Uses: T (Tumour size) N (Lymph node involvement) M (Metastasis site: M1a = lung, M1b = other) Grade (G1–G4) 6. T Category Definitions (AJCC) T1: ≤5 cm T2: >5–10 cm T3: >10–15 cm T4: >15 cm 7. AJCC Bone Staging Table StageTNMGradeIAT1N0M0G1–2IBT2–T3N0M0G1–2IIAT1N0M0G3–4IIBT2N0M0G3–4IIIT3N0M0G3–4IVAny TN1 or M1Any MAny G 8. AJCC – Soft Tissue Sarcomas (Extremity & Trunk) Uses TNM + Grade system. Version 8 no longer considers superficial vs deep location. Grade Definitions: G1: Well-differentiated (e.g., liposarcoma) G2: Moderately differentiated (e.g., leiomyosarcoma) G3: Poorly/undifferentiated (e.g., pleomorphic or synovial sarcoma) References Siegel, G. W., & Biermann, J. S. OKU: Musculoskeletal Tumours 5 Choi, J. H., & Ro, J. Y. 2020 WHO Classification of Bone Tumours Tanaka, K., & Ozaki, T. AJCC 8th Edition – Bone & Soft Tissue Tumours Enneking Staging – Bone Sarcomas AJCC Staging in Primary Bone Malignancies AJCC – Soft Tissue Sarcomas 8th AJCC Staging of Soft Tissue Sarcomas of the Extremities and Trunk Previous Next

< Back Dr. Recep DINCER Spinal Cord Monitoring Spinal cord monitoring is an essential intraoperative tool used to prevent neurological injury during spinal surgery. The main modalities include somatosensory evoked potentials (SEP) for dorsal column function, motor evoked potentials (MEP) for corticospinal tracts, and electromyography (EMG) for nerve root integrity. SEPs are reliable and anesthetic-resistant but limited to sensory pathways, while MEPs are highly sensitive to anterior spinal ischemia yet affected by anesthesia. EMG, both spontaneous and triggered, helps identify nerve irritation or pedicle screw breaches in real time. A >50% reduction in signal amplitude or latency prolongation indicates potential cord compromise requiring immediate correction. Combined multimodal monitoring significantly improves intraoperative safety and postoperative neurological outcomes. SPINAL CORD MONITORING Spinal cord monitoring is a method to detect injury to the spinal cord during operative procedures most common forms are EMG (electromyography) SEP (somatosensory evoked potentials) 25% sensitive, 100% specific MEP (motor evoked potentials) 100% sensitive, 100% specific ANATOMY Spinal cord pathways sensory (afferent) dorsal column spinothalamic tract motor (efferent) lateral corticospinal tract ventral corticospinal tract Blood supply anterior spinal artery primary blood supply to anterior 2/3 of spinal cord, including both the lateral corticospinal tract and ventral corticospinal tract posterior spinal artery (right and left) primary blood supply to the dorsal sensory columns SENSORY EVOKED POTENTIALS (SEPS) Function monitor integrity of dorsal column sensory pathways of the spinal cord Technique signal initiation lower extremity usually involves stimulation of posterior tibial nerve behind ankle upper extremity usually involves stimulation of ulnar nerve signal recording transcranial recording of somatosensory cortex Advantages reliable and unaffected by anesthetics administering propofol with ketamine intravenously is recommended neuromuscular blocking agents do not affect the SEP Disadvantages not reliable for monitoring the integrity of the anterior spinal cord pathways reports exist of an ischemic injury leading to paralysis despite normal SEP monitoring during surgery changes in body temperature, blood pressure, circulating blood volume, arterial blood oxygen saturation, and intracranial pressure influence the SEP Intraoperative considerations loss of signals during distraction mandates immediate removal of device and repeated assessment of signals decrease in amplitude of 50% and/or 10% prolongation in latency is considered a significant change changes should be confirmed by at least three recordings. When the wave pattern suddenly changes, the following factors should be checked: · The surgical procedure, accidental lesion to the spinal cord, aggressive distraction, derotation, etc. · Hardware-related issues, electrode dislodgment, cable lesion, and amplifier and stimulator problems. If these issues occur, the artifact pattern is affected. · Changes in the volume of the anesthetic agent and neuromuscular blocking agent. MOTOR EVOKED POTENTIALS (MEP) Function monitor integrity of lateral and ventral corticospinal tracts of the spinal cord Technique signal initiation transcranial stimulation of motor cortex signal recording muscle contraction in extremity (gastroc, soleus, EHL of lower extremity) Advantages effective at detecting a ischemic injury (loss of anterior spinal artery) in anterior 2/3 of spinal cord Disadvantages often unreliable due to effects of anesthesia Intraoperative considerations loss of signals during distraction mandates immediate removal of device and repeated assessment of monitoring signals >100 V increase in threshold is suggestive of an early injury >50% decrease in MEP amplitude is considered significant ELECTROMYOGRAPHY (SPONTANEOUS) Introduction monitor integrity of specific spinal nerve roots Technique concept microtrauma to nerve root during surgery causes depolarization and a resulting action potential in the muscle that can be recorded contact of a surgical instrument with nerve root will lead to "burst activity" and has no clinical significance significant injury or traction to a nerve root will lead to "sustained train" activity, which may be clinically significant signal initiation mechanical stimulation (surgical manipulation) of nerve root signal recording muscle contraction in extremity Advantages allows monitoring of specific nerve roots Disadvantages may be overly sensitive (i.e. sustained train activity does not necessarily reflect a nerve root injury) ELECTRICAL ELECTROMYOGRAPHY (TRIGGERED) Introduction allows detection of a breached pedicle screw Technique concept bone conducts electricity poorly an electrically stimulated pedicle screw that is confined to bone will not stimulate a nerve root if there is a breach in a pedicle, stimulation of the screw will lead to activity of that specific nerve root signal initiation electrical stimulation of placed pedicle screw signal recording muscle contraction in extremity thresholds <8 mA may be indicative of a breach Advantages allows monitoring of specific nerve roots Disadvantages may be overly sensitive (i.e. sustained train activity does not necessarily reflect a nerve root injury) References: Banoub M, Tetzlaff JE, Schubert A. Pharmacologic and physiologic influences affecting sensory evoked potentials: implications for perioperative monitoring. Anesthesiology. 2003;99(3):716–737. Lall RR, Hauptman JS, Munoz C, Cybulski GR, Koski T, Ganju A, Fessler RG, Smith ZA. Intraoperative neurophysiological monitoring in spine surgery: indications, efficacy, and role of the preoperative checklist. Neurosurgical Focus (FOCUS). 2012;33(5):E10. doi:10.3171/2012.9.FOCUS12235 . Abbasi H, Moore DJ, Rajaeirad M, Zhan J. Screw stimulation thresholds for neuromonitoring in minimally invasive oblique lateral lumbar interbody fusion (OLLIF): a correlational study. Cureus. 2024;16(6):e62859. doi:10.7759/cureus.62859. Previous Next

< Back Classification Systems Q D shoulder-elbow-classification Previous Next

< Back Evidence-Based Medicine Spot Knowledge Definition: Integration of best research evidence + clinical expertise + patient values Goal: Maximise quality & duration of life, improve decision-making 🔄 EBM 5 Steps Formulate clinical question Search for evidence Critically appraise evidence Apply to practice Evaluate outcome Evidence-Based Medicine: Definition, Process, and Levels of Evidence Definition and Purpose Evidence-based medicine (EBM) is an approach that integrates clinical expertise with the best available evidence from systematic research. The aim is to maximize both the quality and duration of patients’ lives. This approach emphasizes the integration of empirical evidence, clinical experience, and patient values. Fundamental Steps The EBM process consists of five stages: Formulating an answerable clinical question. Identifying and retrieving the evidence. Critical appraisal of the evidence. Integrating the evidence into clinical practice. Evaluating the effectiveness and efficiency of the application. The appraisal of evidence is not limited to randomized controlled trials and meta-analyses. Other study designs presenting consistent findings may also contribute to clinical practice. Studies are classified according to their quality and reliability. Levels of Evidence and Study Types Therapeutic Studies Level I: High-quality randomized controlled trials (RCTs) or homogeneous systematic reviews. Level II: Lower-quality RCTs, prospective comparative studies. Level III: Case-control studies, retrospective comparative studies. Level IV: Low-quality cohort studies or case series. Level V: Expert opinion. Prognostic Studies Level I: High-quality prospective studies and systematic reviews thereof. Level II: Retrospective studies or lower-quality prospective studies. Level III: Case-control studies. Level IV: Case series. Level V: Expert opinion. Diagnostic Studies Level I: Development of diagnostic criteria tested in consecutive series of patients, validated against an appropriate “gold standard.” Level II–IV: Development of criteria tested in more limited samples or against lower-quality standards. Level V: Expert opinion. Economic and Decision Analyses Level I: Robust data from multiple sources, supported by sensitivity analyses. Level II: Analyses based on limited data and resources. Level III–IV: Analyses based on weak assumptions or limited sensitivity testing. Level V: Expert opinion. Key Concepts in Evidence-Based Medicine Frequently used concepts in EBM include: Absolute Risk Reduction (ARR): The difference in event rates between treatment and control groups. Relative Risk Reduction (RRR): The proportional risk reduction achieved by the intervention. Number Needed to Treat (NNT): The number of patients that must be treated to prevent one adverse outcome. Likelihood ratios, sensitivity, specificity, positive and negative predictive values: Indicators of diagnostic test performance. Randomized Controlled Trial (RCT): A design in which treatment and control groups are assigned randomly, considered the strongest source of evidence. Meta-analysis and Systematic Review: Methods combining results from multiple studies to generate stronger evidence. Type I error (α) and Type II error (β): The probabilities of false-positive and false-negative results, respectively. Clinical Relevance The evidence-based approach provides guidance not only in treatment selection but also in diagnosis, prognosis, and health economics. The reliability of clinical decision-making depends on the level of evidence employed. High-quality studies offer clinicians stronger and more dependable guidance. Conclusion Evidence-based medicine grounds healthcare decision-making on a scientific basis. Its primary goal is to maximize patient benefit. The integration of clinical expertise, patient preferences, and robust scientific evidence constitutes the foundation of modern medical practice. References 1. StatPearls. Evidence-Based Medicine. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan. PMID: 35412347. 2. Howick J, Chalmers I, Glasziou P, Greenhalgh T, Heneghan C, Liberati A, et al. The Oxford Levels of Evidence 2. Oxford Centre for Evidence-Based Medicine; 2011. 3. Puljak L. The difference between evidence-based medicine, evidence-informed practice, and evidence generation. J Clin Epidemiol . 2022;145:1–3. doi:10.1016/j.jclinepi.2021.12.002 Previous Next

< Back Elbow Injuries Elbow injuries include a spectrum from dislocations to complex fracture-dislocations and can involve multiple anatomic stabilizers, particularly in adults. Common elbow injuries include radial head fractures, olecranon fractures, and terrible triad injuries (elbow dislocation + radial head + coronoid fracture). Stability assessment after reduction is crucial. Radial head arthroplasty or fixation, ligament repair, and early motion protocols are often employed. Pediatric injuries like lateral condyle fractures or medial epicondyle avulsions also demand careful management. Neurovascular exam is essential due to proximity of the ulnar and median nerves and the brachial artery. elbow-injuries Previous Next