A Twenty-two-Year-Old Man with Mild Hip Pain Prior to Fracture

We performed en bloc resection of the femoral head and reconstruction with a total hip arthroplasty with a ceramic-on-ceramic articulation that included a COREN cup and ID stem (Corentec, Cheonan, Korea) and a BIOLOX delta head and liner (CeramTec, Plochingen, Germany). To avoid seeding of the tumor cells, we performed the neck osteotomy at the upper margin of the lesser trochanter. The pathologic report confirmed a chondroblastoma (Figs. 4-A and 4-B). A functional evaluation was performed with the International Society of Limb Salvage (ISOLS) classification system, which includes six parameters: pain, function, emotional acceptance, use of walking supports, walking ability, and gait. Each category is rated 0 to 5, with 0 being the worst score and 5 the best score, with a maximum score of 30. A score of 24 to 30 is considered excellent, 18 to 23 is considered good, 12 to 17 is considered fair, and less than 12 points is considered poor. Fifteen months after the second surgery, the ISOLS scores were 26 for the right hip and 29 for the left hip, and the patient had returned to work (Fig. 5).

Reference: Yoon B-H, Cho HS, Lee Y-K, Koo K-H. Metachronous bilateral chondroblastoma of the proximal part of the femur with a pathologic fracture: a case report. JBJS Case Connect. 2014 Oct 08;4(4):e93.

Chondroblastoma was first described as a benign tumor. This view has been supported by many reports. However, some studies have reported more aggressive lesions that have a tendency for multiple relapses and metastasis or malignant transformation of the chondroblastoma. To our knowledge, there have been no previous reports of metachronous bilateral chondroblastoma. Metastatic chondroblastomas are very rare (0.8% to 6% of chondroblastomas); they can metastasize, most commonly to the lung, neighboring or distal bones, and soft tissues. Lung metastasis can occur as a result of tumor embolization after surgical manipulation, but it usually develops following local recurrence of the primary tumor. Therefore, full staging with chest radiographs and/or CT of the chest is advisable with any locally recurrent chondroblastoma. Neither radiographs nor CT revealed metastatic lesions in our patient. The term “malignant chondroblastoma” is controversial. Some authors consider locally aggressive chondroblastomas to be malignant, even in the absence of metastasis, and they can be associated with high mortality. Neither pleomorphic cells nor mitotic figures were present on histological examination in our case, so neither lesion was diagnosed as malignant. Chondroblastomas containing foci of aneurysmal bone cyst have been reported to show a higher recurrence rate than those without such foci. In our patient, hemorrhagic cystic areas were seen; however, we are unaware of any correlation between this finding and metachronous lesions. There have been two previously reported cases of multifocal chondroblastoma, but both showed conventional histology and were considered multiple primary lesions. In one of these cases, there was an interval of seven years between recognition of the two lesions, and there were no clinical or histological features of malignant tumor. The proximal part of the femur is a common site for primary bone tumors or metastasis, and two-thirds of all long-bone pathologic fractures occur in the femur, usually involving a proximal lesion. When there is a pathologic proximal femoral fracture in a patient with a good life expectancy, an endoprosthetic replacement is a sensible option, both functionally and oncologically. Proximal femoral implants have greater survival rates than implants at other sites; implant survival rates of 77% to 94% at ten years with revision as an end point have been reported. Although there was no acetabular involvement in our patient, we performed total hip arthroplasty because we anticipated high risk for a later revision secondary to acetabular erosion. The femoral head is the third most common site for chondroblastoma. We considered performing surgical curettage with or without bone graft of our patient’s left-sided lesion, but the approach to the femoral head is complex; it is difficult to determine the optimal extent of curettage under fluoroscopic guidance. The recurrence rate of chondroblastomas of the femoral head is as high as 21%, and en bloc resection would be expected to have a low risk of local recurrence. There have been reports of the development of osteoarthritis of the hip joint secondary to femoral head collapse after curettage of lesions in the femoral head. The size of the lesion on the left side in our patient was large and very close to the articular margin. In such cases, en bloc resection with total hip arthroplasty is an alternative option that can avoid the common complications of local recurrence and can prevent the development of osteoarthritis. After full counseling with our patient regarding the lesion, we performed a tumor resection with a total hip arthroplasty. We believe that use of fourth-generation ceramic-on-ceramic implants in total hip arthroplasty should have a prolonged duration as long as there is no recurrence of the lesion.

Reference: Yoon B-H, Cho HS, Lee Y-K, Koo K-H. Metachronous bilateral chondroblastoma of the proximal part of the femur with a pathologic fracture: a case report. JBJS Case Connect. 2014 Oct 08;4(4):e93.