Short-term results of the M2a-taper metal-on-metal articulation.

A polyethylene-free, metal-on-metal acetabular system (M2a-taper [Biomet, Inc., Warsaw, IN]) was designed in an effort to improve total hip arthroplasty (THA) longevity. Minimum 2-year follow-up results involving 72 polyethylene liner THAs and 78 metal liner THAs from a multicenter, randomized, controlled, investigational device exemption study are reported. Mean Harris hip scores of 95.54 (polyethylene liner group) and 95.23 (metal liner group) were reported at mean follow-up intervals of 3.29 and 3.23 years. Radiographic evaluation revealed no evidence of early failure. No acetabular components have been revised or are pending revision. No statistically significant differences in the data were calculated between liner types except for the immediate postoperative (P=.0415) and minimum 2-year follow-up (P=.0341) angles of inclination. The M2a-taper metal-on-metal articulation may represent a viable alternative for THA in younger, higher demand patients.

Orthopaedic implant-related sarcoma: a study of twelve cases.

Sarcoma developing in association with a metallic orthopaedic prosthesis or hardware is an uncommon, but well recognized complication. We review 12 cases of sarcomas arising in bone or soft tissue at the site of orthopaedic hardware or a prosthetic joint. Nine patients were male, and three were female. Their ages ranged from 18 to 85 (mean 55) years at the time of diagnosis of the malignancy. Five patients had undergone hip arthroplasty for degenerative joint disease, four had been treated with intramedullary nail placement for fracture, two had staples placed for fixation of osteotomy, and one had hardware placed for fracture fixation followed years later by a hip arthroplasty. The time interval between the placement of hardware and diagnosis of sarcoma was known in 11 cases and ranged from 2.5 to 33 (mean 11) years. The patients presented with pain, swelling, or loosening of hardware and were found to have a destructive bone or soft tissue mass on radiography. Two sarcomas were located primarily in the soft tissue and 10 in bone. Seven patients developed osteosarcoma, four malignant fibrous histiocytoma, and one a malignant peripheral nerve sheath tumor. All sarcomas were high grade. Three patients had metastatic disease at the time of diagnosis. Follow-up was available on eight patients: five patients died of disease 2 months to 8 years (mean 26 months) after diagnosis; two patients died without evidence of disease 7 and 30 months after diagnosis; and one patient is alive and free of disease 8 years after diagnosis. Sarcomas that occur adjacent to orthopaedic prostheses or hardware are of varied types, but are usually osteosarcoma or malignant fibrous histiocytoma. They behave aggressively and frequently metastasize. Clinically, they should be distinguished from non-neoplastic reactions associated with implants, such as infection and a reaction to prosthetic wear debris.

Examination of tumor and tumor-like conditions of bone.

Surgical pathology specimens composed of bone, ranging from core biopsy to limb amputation specimens, require special attention, processing, and often unique equipment. This readily translates into additional handling steps and time, especially when one factors in clinical correlation with the surgeon and radiologic review of all images with a knowledgeable musculoskeletal radiologist. When these factors are superimposed on the rarity of these lesions in routine practice, it is not surprising that most trainees, as well as seasoned pathologists, are wary of these lesions. In this report, we use a case of osteofibrous dysplasia (Campanacci's disease) to demonstrate the dissection of such a surgical specimen and complete the report with a brief discussion of the entity.

Osteosarcoma in a patient with McCune-Albright syndrome and Mazabraud's syndrome.

Sarcomas infrequently develop in osseous sites of fibrous dysplasia. We report a patient with Mazabraud's syndrome (polyostotic fibrous dysplasia and soft tissue myxomas) complicated by the development of osteogenic sarcoma in a bone affected by fibrous dysplasia. This is the third case of osteosarcoma within the small population of reported patients with Mazabraud's syndrome. There may be an increased incidence of malignant transformation in these individuals' dysplastic bones above that associated with patients suffering from fibrous dysplasia alone.

Use of polymethylmethacrylate in large osseous defects in the foot and ankle following tumor excision.

Foot and ankle surgeons are occasionally confronted with having to fill large defects following excision of osseous lesions. This can prove to be quite challenging to the surgeon in regards to the requirement of large amounts of autogenous, allographic, or synthetic bone graft material. The amount of time spent nonweightbearing postoperatively can be quite prolonged, and the evaluation for tumor recurrence at the graft--host interface is difficult to ascertain. Polymethylmethacrylate has been used extensively in orthopedic surgery for many years in a safe manner for total joint replacement. It has also been used to fill large defects following tumor excision (i.e., giant cell tumor) and as an alternative to bone graft. This article briefly reviews the concepts of using polymethylmethacrylate in this manner and presents the use of polymethylmethacrylate in the treatment of foot and ankle lesions with three case presentations. The authors' purpose for this paper is to simply expand on the current medical literature available regarding the use of polymethylmethacrylate in the foot and ankle and to increase the awareness of foot and ankle surgeons regarding its use as a treatment alternative. A follow-up to this article is planned to present a larger patient population, longer term follow-up, and outcomes data.

Extraskeletal osteosarcoma: an unusual presentation as tarsal tunnel syndrome.

Tarsal tunnel syndrome is a compressive neuropathy caused by intrinsic or extrinsic pressure on the posterior tibial nerve or one of its terminal branches. A mass in association with tarsal tunnel syndrome is most likely a benign tumor or tumor-like condition, although a more malignant tumor must be in the differential diagnosis. We report an unusual case of an extraskeletal osteosarcoma causing tarsal tunnel syndrome.

Small cell osteosarcoma of the soft tissue.

The lesion we described is an osteoid producing mitotically active spindle cell soft tissue neoplasm, which has light and ultrastructural features of an osteosarcoma. By immunohistochemistry it marks with p30/32MIC2-directed antibodies but fails to react with antibodies associated with other soft tissue neoplasms. The precise histogenesis of the lesion is unknown, but failure to elicit a periosteal reaction makes the periosteum less likely to be the primary tissue of origin. The failure to demonstrate any radiologic or histologic evidence of involvement of the underlying bone leaves the soft tissue as the most reasonable site of origin, although the parosteal region cannot be completely excluded.

Hip osteonecrosis secondary to the administration of corticosteroids for feigned bronchial asthma. The clinical spectrum of the factitious disorders.

We describe the case of a woman who developed hip osteonecrosis after prolonged use of corticosteroids for feigned bronchial asthma. This type of musculoskeletal manifestation of the factitious disorders has not been reported previously.

Massive bone allografts for traumatic skeletal defects.

Large bone allograft transplants have been successfully used to reconstruct skeletal defects created by tumor resections and failed arthroplasties, but little has been reported on their use in traumatic defects. Of approximately 500 allograft procedures done at the Massachusetts General Hospital from 1979 to 1988, 11 were done for restoration of traumatic bone loss. The average age of the patients was 30 (range 11 to 71 years), and the location of the defect was the tibia or femur in 10 of the 11 patients studied. Eight osteoarticular grafts (six hemicondylar and two total condylar) and three intercalary grafts were used for six open and five closed fractures. The time from injury to reconstruction averaged 17 months (3 to 96 months). Primary reconstruction was done in three cases and a salvage procedure in eight. Patients were assessed by the operating surgeon and a physical therapist using an evaluation system that considers function, life-style, and emotional acceptance. According to the system, nine patients had excellent or good results (six hemicondylar grafts, three intercalary grafts), one patient had a fair result (total elbow graft), and one patient had failure of a total condylar graft and subsequently required an amputation. This study suggests that large bone allografts are of value in reconstructing traumatic skeletal defects, especially those involving an articular surface in a young patient.

Resection and reconstruction for soft-tissue sarcomas of the extremity.

Soft-tissue sarcomas are uncommon malignant tumors, and when a diagnosis is made early, the patient has up to an 80% chance of surviving. In treating soft-tissue sarcomas, the goal of the surgeon is the prolongation of patient survival, the total eradication of local disease, and the minimization of functional deficits. In addition to treatment, this article discusses evaluation, histology, and staging.

Treatment of benign lesions of the femoral head and neck.

Benign lesions of the proximal femur usually weaken the supporting framework in the femoral neck. Of seven patients aged 11 through 26 years with the diagnosis of fibrous dysplasia (four), aneurysmal bone cyst (two), and simple bone cyst (one), six were treated with curretage and an autogenous fibula strut graft in conjunction with a sliding hip screw. One patient was treated with only the curretage and strut graft. The functional results were excellent (five), good (one), and fair (one), with no local recurrence. In treating fibrous dysplasia, dysplastic bone should be supplemented with grafts of cortical bone. This construct provides increased strength and prevents deformity and fracture, but it does not eradicate the disease. Internal fixation promotes union of the cortical graft to the host cancellous bone. The sliding screw stabilizes the bone and eliminates the need for plaster casts.