R. S. Sneath

Endoprosthetic replacement of the proximal tibia.

We have performed endoprosthetic replacement after resection of tumours of the proximal tibia on 151 patients over a period of 20 years. During this period limb-salvage surgery was achieved in 88% of patients with tumours of the proximal tibia. Both the implant and the operative technique have been gradually modified in order to reduce complications. An initial rate of infection of 36% has been reduced to 12% by the use of a flap of the medial gastrocnemius, to which the divided patellar tendon is attached. Loosening and breakage of the implant have been further causes of failure. We found that the probability of further surgical procedures being required was 70% at ten years and the risk of amputation, 25%. The development of a new rotating hinge endoprosthesis may lower the incidence of mechanical problems. Limb salvage for tumours of the proximal tibia is fraught with complications, but the good functional outcome in successful cases justifies its continued use.

Prosthetic replacement of the distal femur for primary bone tumours

Over a 16-year period, 135 custom-made distal femoral prostheses, based on a fully constrained Stanmore-type knee replacement, were used in the treatment of primary malignant or aggressive benign tumours. Survivorship analysis showed a cumulative success rate of 72% at five years and 64% at seven years. Intact prostheses in 91% of the surviving patients gave good or excellent functional results. Deep infection was the major complication, occurring in 6.8% of cases; clinical aseptic loosening occurred in 6.0%. Revision surgery was carried out for loosening and infection, and the early results are encouraging. We conclude that prosthetic replacement of the distal femur can meet the objectives of limb salvage surgery.

Reconstruction of the Hemipelvis after the Excision of Malignant Tumours

We treated 35 patients with primary malignant tumours of the periacetabular area by resection and prosthetic reconstruction of the defect. At a mean follow-up of 84 months, 15 patients (43%) were free from disease. The most common complications were deep infection (26%), local recurrence (24%) and recurrent dislocation of the hip (17%). The surviving patients achieved an average of 70% of their premorbid function. This method of reconstruction has a high morbidity and should be performed only at specialist centres, but the functional and oncological outcomes are satisfactory.

Hindquarter amputation for tumours of the musculoskeletal system

We reviewed 34 hindquarter amputations performed for malignant tumours around the hip from 1971 to 1988, classifying them as palliative or curative according to the resection margins or the presence of disseminated disease at the time of surgery. There were three peri-operative deaths, 12 palliative and 19 curative procedures. Ten patients died of disseminated disease within a year of surgery, eight of whom had had a palliative operation. Three patients died between one and five years after palliative surgery. One died of unrelated disease at nine years. Seventeen patients are disease free an average of 31 months from surgery, 16 after curative procedures. The median survival after palliative amputations was six months and the 5-year survival rate for curative cases was 83%.

RECONSTRUCTION OF THE HEMIPELVIS AFTER THE EXCISION OF MALIGNANT TUMOURS

We treated 35 patients with primary malignant tumours of the periacetabular area by resection and prosthetic reconstruction of the defect. At a mean follow-up of 84 months, 15 patients (43%) were free from disease. The most common complications were deep infection (26%), local recurrence (24%) and recurrent dislocation of the hip (17%). The surviving patients achieved an average of 70% of their premorbid function.This method of reconstruction has a high morbidity and should be performed only at specialist centres, but the functional and oncological outcomes are satisfactory.

GROWING ENDOPROSTHESES FOR PRIMARY MALIGNANT BONE TUMORS

Twenty years of experience with the use of growing endoprostheses for limb salvage in skeletally immature patients is reported. Alternatives for the management of primary malignant bone tumors in this group of patients are amputation, rotationplasty, and allograft or autograft reconstruction. The development of the currently used implant is charted, with commentary on the complications and difficulties which gave rise to design changes. Over this period, 123 expanding endoprostheses have been inserted in 108 patients in this institution, and the results of a series of 54 consecutive distal femoral replacements are reported. The mean functional score was 72%, and the local recurrence rate was 11%. The technique was successful in maintaining limb-length equality. We conclude that in specialized centers of orthopedic oncology that utilize an endoprosthesis with proven reliability of the expansion mechanism, the short- and long-term results of this technique justify its continued use.

Diagnosing musculoskeletal tumours

In 1993 we became aware of a worrying increase in apparent errors in the histopathological diagnosis of musculoskeletal tumours in our Unit. As a result all cases seen over the past 8 years were reviewed by an independent panel. Of the 1996 cases reviewed there was an error in 87. In 54 cases (2.7%) this had led to some significant change in the active management of the patient. The main areas where errors arose were in those very cases where clinical and radiological features were not helpful in confirming or refuting the diagnosis. The incidence of errors rose with the passage of time, possibly related to a deterioration in the pathologist’s health. The error rate in diagnosing bone tumours in previously published series ranges from 9 to 40%. To ensure as accurate a rate of diagnosis as possible multidisciplinary working and regular audit are essential.

Uncemented intramedullary fixation of implants using polyethylene sleeves. A roentgenographic study.

Forty-three prostheses with noncemented, high-molecular-weight, polyethylene-sleeved components were used in the treatment of bone tumors around the knee in growing children. The average age of the patients was 11 years. There were 27 boys and 16 girls. There were 17 sleeved components in the distal femur and 26 in the proximal tibia. The average follow-up time was 27 months. The roentgenograms were nominally obtained at three, six, 12, 18, and 24 months, and irregularly thereafter, and were assessed using a zonal evaluation scheme. A sclerotic interface around the polyethylene sleeves invariably developed and progressed in density up to 28 months postoperatively. There were significant zonal differences in sclerosis, particularly between the plateau and the mid-sleeve zone. Only in one patient did a sleeve become loose and require revision.

Endoprosthetic Replacements of the Proximal Tibia

Tumors of the proximal tibia are common, representing between 12% and 15% of all osteosarcomas, 22% of giant cell tumours and smaller proportions of both Ewing’s tumors and chondrosarcomas (Huvos 1979; Dahlin and Unni 1986).

Management of a huge tumour of the humerus by total replacement of the humerus: an 11-year follow-up

Abstract A massive tumour of the humerus was replaced using a total humerus replacement. The clinical and functional outcome at 11 years remains excellent.