Chondroblastom

Effect of Thermal Ablation on Growth Plates: A Study to Explore the Thermal Threshold of Rabbit Growth Plates During Microwave Ablation

PURPOSE

To explore the temperature threshold of thermal damage to growth plates.

METHODS

Nine rabbits were divided into three groups for femoral ablation, exposing the growth plate to different temperatures (T1 = 43-45 °C; T2 = 46-48 °C; T3 = 49-51 °C). After 5 weeks, the changes in the femurs were assessed by macroscopic images, micro-CT, haematoxylin and eosin staining, and immunohistochemistry of Col2a1 (type II collagen). At the cellular level, rabbit epiphyseal chondrocytes were exposed to 37 °C, 44 °C, 47 °C and 50 °C for 5 min. Then, proliferation and chondrogenic differentiation were detected.

RESULTS

The rabbits in the T2 and T3 groups developed length discrepancies and axial deviations of femurs, abnormal newly formed bone in the marrow cavity, disorganized growth plates and decreased Col2a1 expression. At the cellular level, the cells exposed to 47 °C and 50 °C for 5 min showed decreased viability, increased apoptosis, decreased extracellular matrix synthesis and decreased matrix mineralization. However, the changes in rabbits in the T1 group and cells at 44 °C did not show a significant difference.

CONCLUSION

The ablation of growth plates at temperatures above 45 °C for 5 min results in decreased chondrocyte viability and disorganized growth plates, leading to growth disturbances. Further studies are warranted to confirm these promising initial results.

Conservative surgery with microwave ablation for recurrent bone tumor in the extremities: a single-center study

BACKGROUND

Surgical treatment for recurrent bone tumors in the extremities still presents a challenge. This study was designed to evaluate the clinical value of microwave ablation in the treatment of recurrent bone tumors.

METHODS

We present 15 patients who underwent microwave ablation for recurrent bone tumors during the last 7 years. The following parameters were analyzed for outcome evaluation: general condition, surgical complications, local disease control, overall survival, and functional score measured using the Musculoskeletal Tumor Society (MSTS) 93 scoring system.

RESULTS

Percutaneous microwave ablation in one patient with osteoid osteoma and another with bone metastasis resulted in postoperative pain relief. Thirteen patients received intraoperative microwave ablation before curettage or resection, including those with giant cell tumors of bone (6), chondroblastoma (2), osteosarcoma (2), undifferentiated sarcoma (1), and bone metastases (2). All patients achieved reasonable local tumor control in the mean follow-up of 29.9 months. The functional score was 24.1 for the 15 patients 6 months after the operation. Four patients had tumor metastasis and died, whereas 3 patients with tumors survived, and the remaining 8 patients without the disease survived.

CONCLUSIONS

Microwave ablation represents an optional method for local control in treating recurrent bone tumors in the extremities.

[Acquired hip joint pathologies in childhood]

A number of different acquired pathologies can affect the pediatric hip joint. The classical and relatively common reactive, inflammatory or traumatic entities have to be differentiated from each other. Rarer and very rare pathologies, such as neoplastic entities or tenosynovial giant cell tumor, must also be considered in the differential diagnostics. The correct diagnosis, treatment planning and follow-up monitoring require close coordination between the departments of pediatric radiology and pediatric orthopedics. Sonography often represents the initial diagnostic step, followed by conventional radiography. Further evaluation of hip joint pathologies requires magnetic resonance imaging. In selected cases computed tomography can also be indicated.

Chondrogenic Bone Tumors: The Importance of Imaging Characteristics

BACKGROUND

 Chondrogenic tumors are the most frequent primary bone tumors. Malignant chondrogenic tumors represent about one quarter of malignant bone tumors. Benign chondrogenic bone tumors are frequent incidental findings at imaging. Radiological parameters may be helpful for identification, characterization, and differential diagnosis.

METHODS

 Systematic PubMed literature research. Identification and review of studies analyzing and describing imaging characteristics of chondrogenic bone tumors.

RESULTS AND CONCLUSIONS

 The 2020 World Health Organization (WHO) classification system differentiates between benign, intermediate (locally aggressive or rarely metastasizing), and malignant chondrogenic tumors. On imaging, typical findings of differentiated chondrogenic tumors are lobulated patterns with a high signal on T2-weighted magnetic resonance imaging (MRI) and ring- and arc-like calcifications on conventional radiography and computed tomography (CT). Depending on the entity, the prevalence of this chondrogenic pattern differs. While high grade tumors may be identified due to aggressive imaging patterns, the differentiation between benign and intermediate grade chondrogenic tumors is challenging, even in an interdisciplinary approach.

KEY POINTS

  · The WHO defines benign, intermediate, and malignant chondrogenic bone tumors. · Frequent benign tumors: osteochondroma and enchondroma; Frequent malignant tumor: conventional chondrosarcoma. · Differentiation between enchondroma versus low-grade chondrosarcoma is challenging for radiologists and pathologists. · Pain, deep scalloping, cortical destruction, bone expansion, soft tissue component: favor chondrosarcoma. · Potential malignant transformation of osteochondroma: progression after skeletal maturity, cartilage cap thickness (> 2 cm adult; > 3 cm child). · Potentially helpful advanced imaging methods: Dynamic MRI, texture analysis, FDG-PET/CT.

CITATION FORMAT

· Engel H, Herget GW, Füllgraf H et al. Chondrogenic Bone Tumors: The Importance of Imaging Characteristics. Fortschr Röntgenstr 2021; 193: 262 - 274.

Anatomical Reconstruction of the Acromion Using an Autologous Iliac Crest Graft for Treatment of Recurrent Chondroblastoma: A Case Report

CASE

A 38-year-old man presented with recurrent chondroblastoma of the acromion after primary curettage and bone grafting. The patient underwent revision surgery with resection of the acromion and reconstruction using an autologous iliac crest graft. He had regained normal shoulder function without recurrence at a follow-up of 17 months.

CONCLUSIONS

This case demonstrates a rare location of chondroblastoma and successful anatomical and functional reconstruction. The described surgical procedure could be considered for large tumorous lesions of the acromion, for which curettage would be insufficient, and to preserve and reconstruct a functionally intact shoulder girdle.

Edema Surrounding Benign Tumors and Tumor-Like Lesions

Objective

To explore the incidence and significance of intra- and extra-osseous edema associated with benign tumors and tumor-like diseases.

Methods

Magnetic resonance imaging (MRI) data from 300 benign osseous tumors and tumor-like diseases diagnosed by pathology were retrospectively reviewed. Borderline tumors, cases associated with pathological fractures, and skull lesions were excluded from the study. Bone marrow and soft tissue edema were defined on T2WI with fat suppression on MRI in all cases. The incidence rate of edema in benign tumors and tumor-like diseases was determined using the χ ² test. The preoperative diagnoses were reviewed, and the effect of edema on the differential diagnosis of benign and malignant tumors was analyzed.

Results

The incidence rate of bone marrow and soft tissue edema associated with benign tumors and tumor-like diseases was 35.7% (107/300), including 84.4% (27/32) Langerhans cell histiocytosis, 86.4% (19/22) osteoblastoma, 93.9% (31/33) osteoid osteoma, and 85.2% (23/27) chondroblastoma cases. There was no statistically significant difference in the incidence of edema among the four diseases (χ ² = 1.7, P > 0.05). Of 107 cases associated with edema, 49 (45.8%) were misdiagnosed as malignant tumors by MRI preoperatively.

Conclusion

Bone marrow and soft tissue edema are a common finding associated with benign bone tumors and tumor-like diseases, and they are frequently detected in Langerhans cell histiocytosis, osteoblastoma, osteoid osteoma, and chondroblastoma.

Have the difficulties and complications of surgical treatment for chondroblastoma of the adjoining knee joint been overestimated?

BACKGROUND AND OBJECTIVE

Chondroblastoma is difficult to treat as the tumor is surrounded by both articular cartilage and the epiphyseal plate. The differences in joint shape further complicate the problem. This retrospective study evaluates the efficacy of intraregional aggressive curettage and allogeneic bone grafting for treating chondroblastoma of the adjoining knee joint.

METHODS

From February 2010 to February 2017, 36 patients with chondroblastoma of the adjoining knee joint were identified. All patients were treated with intraregional aggressive curettage, phenolization, and allogeneic bone grafting. Follow-up for lesion healing, local recurrence, functional outcomes and secondary osteoarthritis were assessed both clinically and radiologically.

RESULTS

Thirty-six patients (mean age 17 years) were enrolled with a mean follow-up of 51.8 months (18-98 months). The tumor locations were as follows: distal femur (14), proximal tibia (20), and patella (2). Only 1 patient relapsed, 10 months post-operation. All patients had good bone healing. No knee varus or valgus deformity developed. The mean Musculoskeletal Tumor Society functional score was 28.6 ± 1.1 post-operation. At the last follow-up, secondary osteoarthritis was found in 1 patient, the patient was asymptomatic.

CONCLUSIONS

Intraregional aggressive curettage, phenolization, and allogeneic bone grafting are effective for treatment of chondroblastoma of the adjoining knee joint.

Long-term follow-up of custom cross-pin fixation of 56 tumour endoprosthesis stems: a single-institution experience

AIMS

Aseptic loosening is a major cause of failure in cemented endoprosthetic reconstructions. This paper presents the long-term outcomes of a custom-designed cross-pin fixation construct designed to minimize rotational stress and subsequent aseptic loosening in selected patients. The paper will also examine the long-term survivorship and modes of failure when using this technique.

PATIENTS AND METHODS

A review of 658 consecutive, prospectively collected cemented endoprosthetic reconstructions for oncological diagnoses at a single centre between 1980 and 2017 was performed. A total of 51 patients were identified with 56 endoprosthetic implants with cross-pin fixation, 21 of which were implanted following primary resection of tumour. Locations included distal femoral (n = 36), proximal femoral (n = 7), intercalary (n = 6), proximal humeral (n = 3), proximal tibial (n = 3), and distal humeral (n = 1).

RESULTS

The median follow-up was 132 months (interquartile range (IQR) 44 to 189). In all, 20 stems required revision: eight for infection, five for structural failure, five for aseptic loosening, and two for tumour progression. Mechanical survivorship at five, ten, and 15 years was 84%, 78%, and 78%, respectively. Mechanical failure rate varied by location, with no mechanical failures of proximal femoral constructs and distal femoral survivorship of 82%, 77%, and 77% at five, ten, and 15 years. The survivorship of primary constructs at five years was 74%, with no failure after 40 months, while the survivorship for revision constructs was 89%, 80%, and 80% at five, ten, and 15 years.

CONCLUSION

The rate of mechanical survivorship in our series is similar to those reported for other methods of reconstruction for short diaphyseal segments, such as compressive osseointegration. The mechanical failure rate differed by location, while there was no substantial difference in long-term survival between primary and revision reconstructions. Overall, custom cross-pin fixation is a viable option for endoprosthetic reconstruction of short metaphyseal segments with an acceptable rate of mechanical failure. Cite this article: Bone Joint J 2019;101-B:724-731.

Modified trapdoor procedures by surgical dislocation approach to treat chondroblastoma of the femoral head

AIMS

The aim of this study was to evaluate the efficacy of the surgical dislocation approach and modified trapdoor procedure for the treatment of chondroblastoma of the femoral head.

PATIENTS AND METHODS

A total of 17 patients (ten boys, seven girls; mean age 16.4 years (11 to 26)) diagnosed with chondroblastoma of the femoral head who underwent surgical dislocation of the hip joint, modified trapdoor procedure, curettage, and bone grafting were enrolled in this study and were followed-up for a mean of 35.9 months (12 to 76). Healing and any local recurrence were assessed via clinical and radiological tests. Functional outcome was evaluated using the Musculoskeletal Tumour Society scoring system (MSTS). Patterns of bone destruction were evaluated using the Lodwick classification. Secondary osteoarthritis was classified via radiological analysis following the Kellgren-Lawrence grading system. Steinberg classification was used to evaluate osteonecrosis of the femoral head.

RESULTS

The epiphyseal plate was open, closing, and closed in five, five, and seven patients, respectively. In total, eight, six, and three patients were classified as having Lodwick classification IA, IB, and IC, respectively. Allogeneic and autogenous bone grafting was used in 13 and four patients, respectively. All patients had good bone healing and no local recurrence was observed. One patient developed osteonecrosis of the femoral head (Steinberg IA) and one developed secondary osteoarthritis of the hip joint (Kellgren-Lawrence Grade II). The mean postoperative MSTS functional score was 27.7 (24 to 30).

CONCLUSION

Surgical dislocation and modified trapdoor procedures are safe and effective techniques for treating chondroblastoma in the femoral head. Cite this article: Bone Joint J 2019;101-B:732-738.