Cartilage Cap Research Articles

Osteochondroma of axis vertebra treated with en bloc resection and arthrodesis

Osteochondromas are capped benign bony neoplasm that forms on the outer surface of the bone. They are most commonly found in appendicular skeletal but rare in the spine. The cervical spine is commonly involved in spinal osteochondromas. Here we discuss a case of a 24-year-old male with osteochondroma arising from the posterior arch of C2 (axis) vertebra presenting with myelopathy. Most of the cases are asymptomatic needing only observation. Surgery is needed in case of progressive neurologic deficit. It is recommended to do an en bloc resection of the lesion along with cartilage cap to prevent recurrence and spinal stabilization with arthrodesis to avoid postoperative kyphosis.

Diagnostic features of lumbar canal osteochondroma and review of literature

Osteochondroma is a common benign primary bone tumor that can be multiple or solitary and is usually caused by a developmental defect in the growth plate. Osteochondroma usually arises from an osteochondroma near the ends of long bones and is less likely to occur in the spine. Data show that the incidence of single spinal osteochondroma is only 1.3%-4%, and the most common sites are cervical vertebra, thoracic vertebra, thoracolumbar and lumbar vertebra. Osteochondroma of the lumbar spine is rare because its ossification center generally ossified around 30 years of age, later than cervical and thoracic vertebrae. Only about 30% of patients with osteochondroma of the lumbar spine had intact cartilage caps. If the thickness of the cartilage cap is assessed, it is difficult to see on conventional radiographs. Conventional radiographic assessment is usually used to diagnose osteochondroma in the extremities, whereas radiographic diagnosis of osteochondroma in the spine is more difficult. This case was reported as a female patient with a single osteochondroma, which occurred in the lumbar spine and had a complete cartilage cap during the operation. This case is rare, which can provide some help for clinical practice to avoid misdiagnosis and missed treatment of this kind of disease.

Surgical management of symptomatic solitary osteochondroma of femur neck in an adult: A case report

Osteochondromas are the common benign bone tumors of the long bones, usually asymptomatic and mostly found incidentally in children and adolescents on radiographs. Osteochondromas are usually present as sessile and pedunculated swelling arising from the metaphyseal region of long bone ends. We reported a 35-year-old woman, who presented with a hard painful mass in the left gluteal region and decreased hip movements. Radiological examination showed a tumor arising from the base of femur neck. The appropriate surgical approach wasused for the complete resection of bone swelling, cartilage cap, and surrounding bursa without hampering surrounding structures as they are at risk of injury during surgical resection of the tumor. Histopathology confirmed the diagnosis of an osteochondroma. Proximal femur or neck of the femur is an unusual site for ostechondroma to occur; the risk of sarcomatous degeneration and malignant transformation of such swelling presenting late is more. Complete resection of such bone tumors keeping in mind the risk associated is the foremost aim.

1456 Back-To-Back Surgeries: A Clinic Case Report Regarding Multiple Complex Spinal Surgeries for Treatment of Multiple Osteochondroma With Histological Conversion to Chondrosarcoma

Abstract Background Multiple Hereditary Osteochondromas [MHO], previously known as multiple hereditary exostoses, is a rare disorder of bone growth, whereby osseous transformation of the cartilage caps within the diaphyses of long bones or flat bones within the skeleton occurs. A significant complication of MHO is the conversion of any present osteochondroma into a malignant chondrosarcoma. Chondrosarcomas are mesenchymal, non-meningothelial tumours and most commonly present with insidious pain, associated neurological deficit by means of impingement of underlying nerves. Case presentation We present a clinical case of a 29-year-old female medical student with a background history of multiple hereditary osteochondromas. A previously competitive cross-fitter, she developed the conversion of MHO into a malignant chondrosarcoma. Presenting to outpatient clinic in late 2017, this lady had a 2-year history of lower back pain and an associated palpable lump. An MRI of the thoracolumbar spine demonstrated a large mass arising from the posterior elements of T11 to L2. A biopsy at the time was found to be of benign pathology, most likely in keeping with this patient’s diagnosis of MHO. The patient returned for review in early 2018, where a repeat MRI showed extension of the previously described lesion into the spinal canal at the level of L1 vertebra. This was concerning that this previously identified osteochondroma lesion could be undergoing malignant transformation. The patient went on to have a series of complex spinal surgeries which we will discuss below.

Computed Tomographic Image Processing and Reconstruction in the Diagnosis of Rare Osteochondroma.

Objective We applied computed tomography (CT) to explore the imaging manifestations of rare parts of osteochondroma. Based on the medical images, deblurring using a convolutional neural network (CNN), and three-dimensional (3D) reconstruction of the images is performed in order to improve the image diagnosis. Methods Twelve cases of osteochondroma in rare locations confirmed by surgical pathology or clinical long-term dynamic observation were retrospectively analyzed using medical imaging and image reconstruction. There are 7 males and 5 females, with an average age of 43 years. CT examinations were performed in all cases. Image deblurring via the GAN model is performed followed by the 3D reconstruction of the higher quality images is implemented. A retrospective study was performed on the imaging manifestations of the above cases; the imaging characteristics were summarized. Results The imaging features are the following lesions, including 4 cases of the proximal radius, 4 cases of the scapula, 2 cases of the pelvis, and 2 cases of the proximal ribs. The cartilage caps, cortex, and sternum were typical structures of the bone surface of the studied cases. In the continuous imaging features, calcification was visible in some cases, and no significant enhancement was seen in enhanced scans; there was no obvious direction of lesion growth. The image processing techniques that we performed are useful in enhancing the quality of the medical diagnosis. Conclusions Rare site osteochondroma has certain imaging features. In most cases, we can accurately diagnose rare site osteochondroma through these features via the image processing methods that are proposed in this paper.

SOFT TISSUE OSTEOCHONDROMA

<h3>Background</h3> Extraskeletal osteochondroma are rare soft tissue tumors occurring in extra-osseous and extrasynovial structures with features of enchondral ossification. Cases have been reported in the hands and feet but are extremely rare in head and neck region. This is a report of a rare case in an extrasynovial location in the head and neck. <h3>Case Report</h3> A 45-year-old male patient presented with a hard tissue lesion in the chin area, with duration >10 years. Bimanual palpation revealed a freely movable 3 × 2 mm feely movable cartilage-like lesion with no attachment to the mandible. A small protrusion through the skin of the chin area was observed. Imaging also revealed a hard tissue lesion lying within the soft tissue. The lesion was excised along with the skin surrounding it. Histology revealed an encapsulated benign lesion arranged in layers of fibrous tissue covering a cap of hyaline cartilage transitioning to trabecular bone with more maturity toward the skin. Features were consistent with a diagnosis of soft tissue osteochondroma. The patient is currently healthy about 14 months after lesion excision. <h3>Discussion</h3> Extraskeletal osteochondromas are believed to be derived pluripotent cells of joint synovium, tenosynovium, and connective tissue. Computed tomography scan helps in demonstrating its extraskeletal location and magnetic resonance imaging helps delineate its borders. Clinicohistopathologically, it has to be differentiated from pseudomalignant osseous tumors, myositis ossificans, ossifying fibromyxoid tumors, and sarcomas. Osteochondroma should be included in the differential diagnosis of some head and neck soft tissue calcified masses. Diagnosis will be aided by adequate imaging and histopathologic examination.

Variation in Articular Cartilage Thickness Among Extant Salamanders and Implications for Limb Function in Stem Tetrapods

The size and shape of articular cartilage in the limbs of extant vertebrates are highly variable, yet they are critical for understanding joint and limb function in an evolutionary context. For example, inferences about unpreserved articular cartilage in early tetrapods have implications for how limb length, joint range of motion, and muscle leverage changed over the tetrapod water-land transition. Extant salamanders, which are often used as functional models for early limbed vertebrates, have much thicker articular cartilage than most vertebrate groups, but the exact proportion of cartilage and how it varies across salamander species is unknown. I aimed to quantify this variation in a sample of 13 salamanders representing a broad range of sizes, modes of life, and genera. Using contrast-enhanced micro-CT, cartilage dimensions and bone length were measured non-destructively in the humerus, radius, ulna, femur, tibia, and fibula of each specimen. Cartilage correction factors were calculated as the combined thickness of the proximal and distal cartilages divided by the length of the bony shaft. Articular cartilage added about 30% to the length of the long bones on average. Cartilage was significantly thicker in aquatic salamanders (42 ± 14% in the humerus and 35 ± 8 in the femur) than in terrestrial salamanders (21 ± 7% in both humerus and femur). There was no consistent relationship between relative cartilage thickness and body size or phylogenetic relatedness. In addition to contributing to limb length, cartilage caps increased the width and breadth of the epiphyses by amounts that varied widely across taxa. To predict the effect of salamander-like cartilage correction factors on muscle leverage, a simplified model of the hindlimb of the Devonian stem tetrapodAcanthostegawas built. In this model, the lever arms of muscles that cross the hip at an oblique angle to the femur was increased by up to six centimeters. Future reconstructions of osteological range of motion and muscle leverage in stem tetrapods and stem amphibians can be made more rigorous by explicitly considering the possible effects of unpreserved cartilage and justifying assumptions based on available data from extant taxa, including aquatic and terrestrial salamanders.

Research progress of autogenous cartilage scaffold carving method in rhinoplasty

To summarize the research progress of autogenous cartilage scaffold carving method in rhinoplasty. The relevant literature about the autogenous cartilage scaffold carving methods in rhinoplasty in resent years at home and abroad was reviewed, and the carving skills, shape, and application scope of different parts of nasal scaffolds were summarized and analyzed. Willow-leaf shape is still the main method of cartilage scaffold in the back of the nose. However, in nasal reconstruction, it can be carved into an L-shaped scaffold with the nasal columella scaffold through mortise and tenon structure. And it can also crush the autologous cartilage and wrap it with the autologous fascia tissue to form a new nasal dorsal scaffold. The nasal tip scaffold is improved by changing the shape of traditional nasal tip cartilage cap and wrapping with fascia tissue; the nasal alar scaffold has M-shape, q-shape, carving methods; the nasal columella and nasal septum are mostly used "2+2" combined fixed scaffold. The cartilage scaffolds of lateral nose and nasal base are mainly carved in the shape of "" and crescent. As a rhinoplasty scaffold, there are various carving methods for autogenous cartilage. With the innovation of surgical technique and the improvement of sculpting technique, the effect of autologous cartilage graft in rhinoplasty is getting better and better; meanwhile, tissue engineered cartilage is being applied in rhinoplasty.

Auricular cartilage versus donor sclera as a wrapping of hydroxyapatite orbital implants.

To retrospectively compare postoperative outcomes after primary enucleation and placement of a hydroxyapatite (HA) implant without wrapping, wrapped with auricular cartilage or donor sclera. Medical records of patients presented as intraocular tumor or severe ocular injury were identified from the electronic medical record system. Cases underwent enucleation and HA orbital implantation were enrolled in this study and were divided into 3 groups according to the wrapping material of HA implant. Cases with autogenous cartilage caps were enrolled in group A (n=11), with donor sclera caps in group B (n=12), and without any wrapping material in group C (n=9). Follow-ups were set at 1, 2wk, 1, 3, 6, and 12mo after surgery. Altogether 32 cases finished the follow-up and were enrolled in this study. Three cases (27.27%) in group A, 4 cases (33.33%) in group B, and 4 cases (44.44%) in group C developed one complication each after surgery. In group A, no HA exposure occurred, but conjunctival inclusion cyst occurred in one and severe conjunctive chemosis in two cases. In group B, one HA exposure occurred, conjunctive inclusion cysts occurred in one, severe conjunctive chemosis occurred in one, and conjunctival granuloma occurred in one case. In group C, one HA exposure occurred, severe conjunctive chemosis occurred in two cases, and conjunctival granuloma occurred in one case. The case of exposure of none-wrapped implant was noted in the first 6mo after placement of the orbital implant. The case of exposure of donor sclera-wrapped implant was noted at the 12mo after placement of the orbital implant. Both exposure cases were treated successfully with conservative treatment. With low incidence of implant exposure and mild complications, auricular cartilage can be a good choice of alternative wrapping material of orbit implant with satisfied outcome.

Arthroscopic Distal Clavicle Glenoid Augmentation: Rationale and Surgical Technique

Glenoid bone loss remains an important determinant of outcome in the surgical management of anterior shoulder instability. Multiple options are available to address this bone loss including autograft bone transfers, such as coracoid or iliac crest grafts. Allograft options include both bone and osteochondral options, such as the distal tibial allograft. Each of these choices has potential advantages and disadvantages. An ideal approach would provide an autograft source of osteochondral material that is well-matched to the defect, readily available, cost effective, and with minimal morbidity. In this article, we present the distal clavicle autograft as an ideal option for consideration in the treatment of glenoid bone loss. The graft has a cortical and cancellous side for direct fixation and is amenable to arthroscopic techniques using standard portals and obviating the need to go near the neurovascular structures of the shoulder. Recent work has demonstrated the utility of this graft in providing an anatomic restoration of the glenoid articular surface with a cartilage cap comparable in thickness to that of the native glenoid. Along with a summary of the pertinent literature, this article outlines the rationale, indications, and technical evolution for this procedure.

Malignant transformation in an 11-year-old child with multiple hereditary exostosis

ABSTRACT BACKGROUND: Multiple hereditary exostosis (MHE) is a rare autosomal dominant disorder predisposing to the development of multiple osteochondromas. Malignant transformation is an uncommon complication of osteochondromas and is especially rare in the paediatric population. Making a diagnosis of malignant transformation is recognised as a challenge globally METHODS: We obtained informed consent and ethics approval prior to reviewing the hospital file, radiology and pathology of our index patient, as well as conducting a directed literature search RESULTS: An 11-year-old male with MHE presented with new onset pain in the right leg with an associated inability to weight bear. Plain radiographs and magnetic resonance imaging (MRI) showed features consistent with malignant transformation. The child underwent a Malawer 1 resection of the proximal fibula with no complications. The pathology confirmed a grade 1 secondary peripheral chondrosarcoma (CS) arising in an osteochondroma The rate of malignant transformation in MHE is as high as 36.3% in select specialist tertiary centres. Ninety per cent of the resultant malignancies are chondrosarcomas. Malignant transformation before the age of 20 years is exceptional. Plain radiology is routinely used for monitoring of patients with MHE. Other modalities exist to assess for cartilage cap thickness, a much-debated criterion of malignant change. Pathology is essential for confirmation of malignant transformation as well as to exclude high grade lesions. Treatment is wide local excision (WLE) with limb-sparing surgery and long-term follow-up to detect for local recurrences. CONCLUSION: The malignant transformation of osteochondromas occurs more frequently in individuals with MHE and may even arise in the paediatric population. In the presence of suspicious clinical or radiological features, en-bloc surgical resection and histopathological correlation is mandatory to make the diagnosis. We encourage a multidisciplinary team approach with collaboration between the orthopaedic surgeon, radiologist and pathologist Level of evidence: Level 5 Keywords: multiple hereditary exostosis (MHE), chondrosarcoma, osteochondroma, malignant transformation

Surgical excision of a solitary osteochondroma arising from the lesser trochanter in an adult: a case report

&lt;p&gt;The occurrence of osteochondroma around the proximal femur is rarely reported as most cases are asymptomatic. We report a rare case of symptomatic solitary osteochondroma arising from the lesser trochanter in a skeletally mature patient causing significant impairment of hip function managed by surgical excision. A 32-year-old male labourer presented with pain and swelling over right hip region for nine months. Radiographic examination (X-ray, MRI, CT) revealed the pathognomonic continuity of the cortex and medulla of the lesion with the parent bone. Cartilage cap cover (measuring 15 mm) on MRI helped to clinch the diagnosis. CT guided biopsy was also suggestive of osteochondroma. The tumour was excised en bloc by posterior approach without the need for hip dislocation. The base of the lesser trochanter was osteotomised and the entire mass with the cartilage cap was removed. A two year follow up has shown no evidence of local recurrence. Surgical excision of a symptomatic osteochondroma is a successful form of treatment with low mortality. Adequate pre-operative radiographic examination is helpful to know the location and local spread of the tumour. Measurement of cartilage cap thickness on MRI is an essential tool to diagnose malignant changes. A safe and adequate resection should be carried out in an effective manner with attention to femoral head vascularity and prevention of local recurrences. Patients with solitary osteochondroma around the proximal femur should be kept under observation to help early detection of malignant changes.&lt;/p&gt;

Authors' Comments—Long-Term Postoperative Cone-Beam Computed Tomography Analysis of Secondary Bone Grafting in 79 Patients With Unrepaired Alveolar Clefts

Authors' Comments—Long-Term Postoperative Cone-Beam Computed Tomography Analysis of Secondary Bone Grafting in 79 Patients With Unrepaired Alveolar Clefts

The Effect of Cartilage Thickness on Reconstructions of Range of Motion and Muscle Leverage in Extinct Tetrapods

Investigating structure‐function relationships in the locomotor system requires an understanding of the complex interactions between bones, cartilage and muscles. This is especially true when examining how these musculoskeletal structures evolved over time and across different environments in both extant and extinct species. We aimed to quantify the effect of different assumptions about cartilage thickness on reconstructions of femur length, hip range of motion (ROM), and muscle leverage in Acanthostega gunnari, one of the earliest known tetrapods and an important species in the vertebrate water‐land transition. We began by examining the hindlimbs of two extant salamanders, Dicamptodon ensatus and Ambystoma mexicanum, using contrast‐enhanced micro‐CT in order to extrapolate the degree to which cartilage thickness might affect femur length in a fossil taxon with salamander‐like morphology. Data visualization software was used to measure the distal and proximal cartilage caps of the femora in each of the extant species. Three‐dimensional modeling software was then used to estimate the center of rotation of the hip joint of Acanthostega. Then, cartilage correction factors were applied based on the measurements from the extant taxa. The limit of ROM was defined as the point at which either the femur contacted the pelvis, or less than 50% of the femoral head remained within the acetabulum. Finally, we used biomechanical modeling software to map muscles onto the bones of Acanthostega and plotted their leverage to examine how assumptions about cartilage affect reconstructions of muscle leverage. Cartilage caps on the proximal end of the femur in Dicamptodon and Ambystoma measured 36% and 14% of femur length, respectively. Taking the most conservative estimate, we modeled Acanthostega with cartilage caps of 0, 7.5 and 13% femur length. The greatest variation in muscle leverage occurred in muscles whose axes of movement were nearly perpendicular to the femur (70–120% of the mean moment arm), as opposed to those muscles whose axes were nearly parallel (less than 10%). We also found that assuming the highest percentage of cartilage increased ROM in protraction and retraction by 15–20° and in elevation and depression by 15–30° but had little to no effect on long‐axis rotation. These results will help to predict the effects of unpreserved soft tissues in future studies that reconstruct ROM and muscle leverage in extinct animals.Effect of different cartilage correction factors on reconstructed hip muscle leverage in the early tetrapod Acanthostega gunnari.The y‐axis shows coefficient of variation of muscle leverage (standard deviation/mean moment arms) across cartilage correction factors of 0, 7.5 and 13% femur length. Moment arms were measured in 3 axes of movement for muscles that cross the hip joint. The greatest effects occurred in muscles with lines of action nearly perpendicular to the femur.Figure 1

Diagnostic Conundrum of an Osteocartilaginous Exostosis of the Patella: An “Ancient” Osteochondroma?

The patella is an uncommon site for a tumor. This report details the incidental finding of an excrescence on the right patella identified in a cadaver during a gross anatomy course. Histological assessment revealed no periosteal surface, a very thin cartilage cap, minimal endochondral ossification, bone intermediate to more cartilage, and degenerative changes. The assessment remains unclear. What is clear, however, is that this incidental finding has served as an excellent interdisciplinary exercise for anatomists and pathologists and has benefited the education of undergraduate and graduate medical students. Accordingly, in addition to the gross pathology and histopathology, a workflow is presented.Support or Funding InformationT. Walley Williams Summer Anatomy Research Fellowship; WV Research Challenge Fund [HEPC.dsr.17.06]

Osteochondromas of the cervical spine-case series and review

ObjectiveCervical spine osteochondromas are rare with approximately 3% of solitary and 7–9% of hereditary osteochondromas occurring in the spine. Almost 50% of spinal osteochondromas occur in the cervical region. MethodsA search of osteochondroma of cervical spine was performed of our radiology database. ResultsIn this study, we present 11 cases of adult cervical spine osteochondromas. These predominantly involved the posterior elements. The cartilage cap was more than 2 cm in 2 cases. There was cord compression in 1 case, foraminal narrowing in 2 patients and vertebral artery compression in 1 case. 6 patients underwent excision with majority being osteochondroma. There was only one case of chondrosarcoma. ConclusionOsteochondromas of cervical spine and extremely rare and symptomatology are due to mass effect. One should be aware of this entitly when analysing cervical spine for neck pain or lump.

Histopathological features of condylar hyperplasia and condylar Osteochondroma: a comparison study

BackgroundBoth mandibular condylar hyperplasia and condylar osteochondroma can lead to maxillofacial skeletal asymmetry and malocclusion, although they exhibit different biological behavior. This study attempted to compare the histological features of mandibular condylar hyperplasia and condylar osteochondroma using hematoxylin-and-eosin (H&E) staining, and immunohistochemistry staining of PCNA and EXT1 with quantitative analysis method.ResultsThe H&E staining showed that condylar hyperplasia and condylar osteochondroma could be divided into four histological types and exhibited features of different endochondral ossification stages. There was evidence of a thicker cartilage cap in condylar osteochondroma as compared condylar hyperplasia (P = 0.018). The percentage of bone formation in condylar osteochondroma was larger than was found in condylar hyperplasia (P = 0.04). Immunohistochemical staining showed that PCNA was mainly located in the undifferentiated mesenchymal layer and the hypertrophic cartilage layer, and there were more PCNA positive cells in the condylar osteochondroma (P = 0.007). EXT1 was mainly expressed in the cartilage layer, and there was also a higher positive rate of EXT1 in condylar osteochondroma (P = 0.0366). The thicker cartilage cap, higher bone formation rate and higher PCNA positive rate indicated a higher rate of proliferative activity in condylar osteochondroma. The more significant positive rate of EXT1 in condylar osteochondroma implied differential biological characteristic as compared to condylar hyperplasia.ConclusionsThese features might be useful in histopathologically distinguishing condylar hyperplasia and osteochondroma.

Scapular osteochondroma

Osteochondromas are tumors composed of medullary and cortical bone with hyaline cartilage caps. Involvement of the scapula is uncommon. We report two cases. Patients may present with pain or symptoms due to compression of the adjacent structures. Surgery is the treatment of choice of symptomatic osteochondromas.

How to Manage Cartilage Injuries?

Although small cartilage injuries are commonly found in knee arthroscopy procedures, significant chondral and osteochondral injuries are relatively infrequent. Incidence of cartilage injury rises when considering traumatic origin, especially when approaching significant ligamentous or meniscal pathology. Options for restoration span the gamut from benign neglect to open procedures that restore both cartilage and subchondral bone. The best choice of procedure largely depends on lesion size, depth, and location. Smaller lesions isolated to cartilage <2 cm2 can be treated with marrow stimulation techniques such as microfracture with or without biologic options (bone marrow aspirate concentrate or platelet-rich plasma with or without cartilage precursors or scaffolds). Microfracture alone in larger lesions has been reported to be less durable and it is therefore not recommended for larger lesions. Smaller lesions <2 cm2 that include a subchondral injury can be treated with osteochondral autograft implantation, in which a core of cartilage and bone is transferred from a relative non-weightbearing surface to the lesion.Larger osteochondral lesions >2 cm2 are better treated with osteochondral allograft transplantation, where osteochondral cores from a size-matched, fresh cadaver are matched to the patient's lesion. This option may require multiple cores to be placed in a “snowman” pattern; however, recent literature demonstrated that a single plug might produce better outcomes. Alternatively, for large chondral-only lesions, a resurfacing procedure may be chosen that may include biologic options. Autologous chondrocyte implantation (ACI), currently in its third iteration (matrix ACI [MACI]), is an excellent choice with good long-term durability. In addition, MACI may be used for chondral lesions in the patellofemoral joint where matching the native joint topology may be more difficult. If the patient has an underlying bone marrow lesion but an intact cartilage cap that appears healthy on arthroscopic examination, one may consider a core decompression and injection with biologics such as BMAC and bony scaffold with fibrin glue (also known as bioplasty).It is also critical that the surgeon address any concomitant knee pathology that would compromise cartilage restoration. This includes addressing malalignment with distal femoral, proximal tibial, or tibial tubercle osteotomy, significant meniscal deficiency with meniscal transplant, and any instability from lack of cruciate or collateral ligaments with ligament reconstruction.

Is the Width of a Surgical Margin Associated with the Outcome of Disease in Patients with Peripheral Chondrosarcoma of the Pelvis? A Multicenter Study.

We attempted to resect peripheral chondrosarcoma of the pelvis with clear margins. Because of the proximity of vessels or organs, there is still concern that narrow surgical margins may have an adverse effect on disease outcomes. Although current guidelines recommend resection of histologic Grade II or Grade III chondrosarcomas with a "wide" margin, there are no specific recommendations for the adequate width of a surgical margin. (1) What is the disease-specific and local recurrence-free survival of patients with peripheral chondrosarcoma of the pelvis treated with resection or amputation? (2) Is the width of a surgical margin associated with the outcome of disease in patients with peripheral chondrosarcoma of the pelvis? (3) Does the histologic grade as determined with a preoperative biopsy correlate with the final grade after resection? (4) What are surgical complications in these patients? We retrospectively reviewed records from three international collaborating hospitals. Between 1983 and 2017, we resected 262 pelvic chondrosarcomas of all types. After reviewing the pathologic reports of these patients, we included 52 patients with peripheral chondrosarcomas of the pelvis who had an osteochondroma-like lesion at the base of the tumor and a cartilage cap with malignant cells in resected specimens. To be eligible for this study, a patient had to have a minimum of 1 year of follow-up. Two patients were excluded because they had less than 1 year of follow-up, leaving 50 patients for inclusion in this study. The median follow-up duration was 7.0 years (interquartile range 2.1-10 years). The median age was 37 years (IQR 29-54 years). The ilium was the most frequently affected bone (in 36 of 50 patients; 72%). The histologic status of the surgical margin was defined as microscopically positive (0 mm), negative < 1 mm, or negative ≥ 1 mm. Thirteen of the 50 patients (26%) had local recurrence. Seven of 34 patients had Grade I tumors, five of 13 had Grade II tumors, and one of three had a Grade III tumor. Nine of 16 patients had multiple local recurrences. Two patients with Grade I tumors and two with Grade II tumors died because of pressure effects caused by local recurrence. The 10-year disease-specific and local recurrence-free survival rates were 90% (95% confidence interval, 70-97) and 69% (95% CI, 52-81), respectively. A surgical margin ≥ 1 mm (n = 16) was associated with a better local recurrence-free survival rate than a surgical margin < 1 mm (n = 17) or 0 mm (n = 11) (10-year local recurrence-free survival: resection margin ≥ 1 mm = 100% versus < 1 mm = 52% [95% CI, 31 to 70]; p = 0.008). No patients with a surgical margin ≥ 1 mm had local recurrence, metastasis, or disease-related death, irrespective of tumor grade. Patients with local recurrence (n = 13) showed worse disease-specific survival than those without local recurrence (n = 37) (10-year disease-specific survival: local recurrence [+] = 59% [95% CI, 16 to 86] versus local recurrence [-] = 100%; p=0.001]). The preoperative biopsy results correctly determined the tumor grade in 15 of 41 patients (37%). The most frequent complication after surgery was local recurrence (13 of 50 patients, 26%). Deep infection was the most frequent nononcologic complication (four patients). We found a high local recurrence rate after surgical treatment of a peripheral pelvic chondrosarcoma, which was related to the width of the surgical margin. These local recurrences led to inoperable recurrent tumors and death. The tumor grade as determined by preoperative biopsy was inaccurate in 2/3 of patients compared with the final histologic assessment. Therefore, we believe every attempt should be made to achieve a negative margin during the initial resection to lessen the likelihood of local recurrence of peripheral chondrosarcoma of the pelvis of all grades. A margin of 1 mm or more appeared to be sufficient in these patients. Level III, therapeutic study.