Overlapping allograft in reconstructive surgery for malignant bone tumours in paediatric patients

The use of allografts for the treatment of bone tumours in children is limited by nonunion and the difficulty of finding a suitable graft. Furthermore, appositional growth can’t be expected of an allograft.

We used an overlapping allograft in 11 children, with a mean age of ten years (4 to 15), with a mean follow-up of 24.1 months (20 to 33). There were five intercalary and six intra-articular resections, and the tumours were in the femur in six cases and the humerus in five. Rates of union, times to union, remodelling patterns and allograft-associated complications were evaluated.

No allograft was removed due to a complication. Of the 16 junctional sites, 15 (94%) showed union at a mean of 3.1 months (2 to 5). Remodelling between host and allograft was seen at 14 junctions at a mean of five months (4 to 7). The mean Musculoskeletal Tumor Society score was 26.5 of 30 (88.3%). One case of nonunion and another with screw protrusion required re-operation.

Overlapping allografts have the potential to shorten time to union, decrease rates of nonunion and have positive appositional growth effect.

A rotating-hinge knee replacement for malignant tumors of the femur and tibia

We evaluated the 2- to 7-year results of a rotating-hinge knee replacement after excision of malignant tumors of the knee joint. There were 25 distal femoral and 7 proximal tibial replacements. The 5-year prosthetic survival for distal femoral replacements was 88%, compared with 58% for proximal tibial replacements. Seven patients underwent prosthetic exchange: 1 for aseptic loosening, 2 for wound slough and perioperative infection, and 4 for articulating component failure. One patient underwent above-knee amputation owing to skin necrosis. The median functional scores at the latest follow-up were 27 by the International Society of Limb Salvage evaluation system and 80 by the Hospital for Special Surgery Knee Score system. This implant is a promising choice for joint reconstruction after excision of tumors at the knee joint.

Algorithm for the surgical treatment of malignant lesions of the proximal tibia

Complications are common among patients treated for malignant lesions of the proximal tibia and can be difficult to manage. This investigation was a retrospective review of 40 patients treated with total knee replacements after proximal tibial resections. Various reconstructive methods were used to fix the prosthetic stems, reestablish the extensor mechanism, and provide soft tissue coverage. Thirty-one patients had adequate followup to allow for review of prosthetic outcome (means, 78 months; range, 25-193 months). Seven patients died with less than 2 years followup, and two patients had postoperative acute infections treated by early amputation to allow chemotherapy to resume promptly. The overall 5-, 8-, and 12-year event free prostheses survival rates were 62%, 33%, and 16%, respectively. Prognostic factors for prosthetic survival were analyzed (age, gender, type of excision, type of prosthesis, type of fixation, and percent of bone resected). None were statistically significant. Patients with less than 40% of the tibia resected had better prosthetic survival at 5 years. The durability of uncemented stem fixation exceeded that of cemented stems. Expected survival of prostheses after revision was 52% at 8 years. The major cause of limb loss was infection. Failure to reconstruct soft tissues satisfactorily caused most failures. Aggressive multistage management of infection is needed. Prosthetic knee replacement is most suitable for patients with cancers that require chemotherapy and for those patients who have short potential survival.

Enhanced expression of cathepsin L in metastatic bone tumors

Cathepsin L is a kind of cystein proteases which are known to facilitate the invasion and metastasis of tumor cells by degrading the components of basement membrane and extracellular matrix. This study was undertaken to investigate the expression of cathepsin L by Northern blot analysis with radiolabeled cDNA specific for cathepsin L in six normal tissues, two osteosarcoma cell lines, MG-63 and Saos-2, six primary bone tumors and six metastatic bone tumors. In six normal tissues, the highest level of cathepsin L was expressed in liver with the descending order of liver > lung > thymus > ovary > kidney > esophagus. One of the two osteosarcoma cell lines established from the primary sites expressed a high level of cathepsin L mRNA. Out of six primary bone tumors, three (50%) expressed cathepsin L mRNA, while all (100%) of six metastatic bone tumors expressed the mRNA. These results demonstrating the higher frequency of expression of cathepsin L in metastatic bone tumors suggest that cathepsin L may participate in tumor invasion and metastasis.

Deletion of Rb1 gene in late osteosarcoma from survivor of unilateral retinoblastoma--a case report

It has been well known that the survivors of retinoblastoma are prone to have osteosarcoma. But the secondary tumor usually occurs in bilateral, hereditary type of retinoblastoma. We report one case of osteosarcoma in a survivor of unilateral, sporadic retinoblastoma. A fourteen year old male presented with a painfully swollen distal forearm of 2 month duration. He had enucleated his left eye 10 years ago due to retinoblastoma with no other adjuvant therapy. We managed him with our conventional protocol and identified deletion of Rb gene from his pathological specimen by using the PCR-RFLP method. This result is unusual for unilateral nonhereditable retinoblastoma and may suggest gene level change even in sporadic cases. And Rb gene study may be helpful for unilateral, sporadic retinoblastoma patient in detecting the possibility of late osteosarcoma.

Synovial sarcoma of the extremities

From May 1985 to March 1990, 18 cases of Enneking's stage II synovial sarcoma of the extremities were treated by a combination of surgery and CYVADIC chemotherapy with or without radiotherapy. The average follow up was 34.7 months. The estimated 5-year survival rate was 78.4% and the continuously disease-free 5-year survival rate was 44.4%. The results were improved by adequate surgery or chemotherapy when local recurrence or metastases had developed. The combination of surgery and CYVADIC chemotherapy with or without radiotherapy was considered to be an effective method of treating this tumour.

Malignant fibrous histiocytoma of the limbs

Between June 1985 and May 1990 we treated 12 patients with malignant fibrous histiocytoma (MFH) of the limbs by a combination of wide excision and adjuvant radiotherapy. The Enneking surgical staging was II in 11 cases and III in 1. There were 6 women and 6 men, with an average age of 54 years. The leg was involved in 8 patients and the arm in 4. Limb salvage was achieved in 10 patients and amputation was performed in 2. All received adjuvant radiotherapy, with an average of 51.5 Gy. In 6 patients adjuvant CYVADIC chemotherapy was administered for an average of 4 cycles. In the other patients this treatment was not tolerated. Local recurrence occurred in 2 patients and metastases to the lung were seen in a further 2. At an average follow-up of 41.3 months, the Kaplan-Meier estimation of 5 year survival was 87.5%, with a 5 year continuous disease-free survival rate of 66.7%.

Pathological responses to preoperative high-dose methotrexate chemotherapy in osteosarcoma--experience in Korea cancer hospital

During the last decade, many clinical investigators at various cancer centers have reported the efficacy of various chemotherapeutic agents in the treatment of osteosarcoma. The regimens using high-dose methotrexate (HDMTX) with citrovorum factor rescue are now considered to be one of the most effective treatments of choice. From December 1989 to May 1991, sixteen patients with Enneking's stage (Enneking et al., 1980) IIB osteosarcoma of the extremities were treated with a high-dose methotrexate regimen. After two cycles of preoperative chemotherapy, an operation was performed; either limb salvage or amputation. The resected lesions were examined pathologically and classified according to Huvos' criteria. On pathological examination, 8 (50%) cases showed Grade IV; 1 (6.25%) Grade III; 4 (25%) Grade II; and 3 (18.75%) Grade I. The types of surgery performed were tumor prosthesis replacement (11); wide resection with or without reconstruction (2); resection and arthrodesis (1); and amputation (2).