Compressive osseointegration promotes viable bone at the endoprosthetic interface: retrieval study of Compress implants.

The Compress implant (Biomet, Warsaw, IN) is an innovative device developed to enable massive endoprosthetic fixation through the application of compressive forces at the bone-implant interface. This design provides immediate, stable anchorage and helps to avoid the long-term complication of aseptic loosening secondary to stress shielding and particle-induced osteolysis seen in conventional, stemmed megaprostheses. The purpose of our study was to evaluate the in vivo biological effects of the high compressive forces attained. Twelve consecutive Compress patients undergoing revision surgery for infection, periprosthetic fracture, or local tumour recurrence were reviewed in order to exclude the possibility of osteonecrosis at the prosthetic interface. Compressive forces ranged from 400-800 lb. Duration of implantation averaged 3.3 years (range 0.4-12.2 years). Two patients with infection demonstrated loosening at the bone-prosthetic interface; otherwise, there was no radiographic evidence of prosthetic failure in any of the patients. No patient demonstrated histological evidence of osteonecrosis. In fact, new woven bone and other findings consistent with viable bone were noted in all of the retrieved specimens.

Effect of chemotherapy on initial compressive osseointegration of tumor endoprostheses.

Chemotherapy has long been suspected of having an adverse effect on bone healing. Massive tumor endoprostheses which achieve osseointegration via compressive force provide a unique model to study the effects of chemotherapy on bone healing. We compared distal femoral bone hypertrophy in patients who received chemotherapy with those who did not. Fifty four patients underwent distal femoral reconstruction with a compression implant. Thirty patients received chemotherapy (Group 1), and 24 did not (Group 2). The group of patients receiving chemotherapy was younger, had lower body mass indices, and had different diagnoses compared to the group of patients not receiving chemotherapy. We used a standardized technique to measure bone growth at the bone-prosthetic interface. The rate of cortical width increase at the bone-prosthetic junction was faster in Group 2 compared to Group 1. Similarly, the increase in cortical width from immediate postop to 3 months and 6 months postop was greater in Group 2 when compared to Group 1. The data suggest chemotherapy administration for musculoskeletal malignancy has a substantial initial adverse effect on bone hypertrophy and a trend towards reduced prosthetic survival. These findings have important implications for the patients with musculoskeletal tumors.

Early distal femoral endoprosthetic survival: cemented stems versus the Compress implant.

Aseptic loosening is well known following endoprosthetic replacement (EPR) using cemented intramedullary stems (CISs). The Compress (CPS) implant uses a novel spring system, achieving immediate, high compression fixation that induces bone hypertrophy and avoids stress shielding. We compared 26 oncologic distal femoral CPS patients treated at the University of California, San Francisco (UCSF, USA) with 26 matched CIS patients from the Royal Orthopaedic Hospital, Birmingham (ROH, UK). The predominant diagnosis was osteosarcoma. Each centre had only one device-related prosthetic failure. In the short term these results show CPS to be safe and effective. We await longer follow-up to assess the ongoing potential for prosthetic failure.

Local control of long bone giant cell tumour using curettage, burring and bone grafting without adjuvant therapy.

Giant cell tumour (GCT) is a benign, but aggressive, primary tumour of the bone. The recurrence rate after surgical treatment has been reported to be as high as 50%. Many surgical techniques have been employed in the treatment of this tumour. More aggressive interventions, such as en bloc resection and bulk allograft or prosthetic reconstruction, are generally understood to be associated with lower rates of local recurrence. However, because of lessened morbidity, intralesional techniques have come to be favoured for this condition. In addition to curettage, various adjuvant procedures and packing materials have been advocated in order to control and reconstruct long bone defects secondary to this neoplasm. We report our experience with 40 long bone GCT patients treated with curettage, burring, bone grafting and no adjuvants between 1997 and 2002. There was a local recurrence rate of 32.5%, with most recurrences noted within the first 30 months after surgery. Minor complications were found in 18% of patients. The risk of local recurrence in this study is acceptable (within the range that has been historically reported for curettage and bone grafting). In cases where more resources are available, the addition of adjuvant therapies, as noted in the recent literature, may be beneficial. The results of this study should be considered when designing multicenteric studies in the future.

Pseudo-osteomyelitic crisis upon presentation of Gaucher disease.

We report on a 4-year-old boy adopted from Paraguay who presented with an acute onset of thigh pain. Initial clinical, imaging, and histopathologic findings suggested florid osteomyelitis. However, the development of pancytopenia on intravenous antibiotics prompted further investigation and the ultimate diagnosis of Gaucher disease. In retrospect, characteristic changes on conventional radiographic and MR images, as well as growth of a contaminant organism, pointed to the diagnosis of pseudo-osteomyelitis rather than osteomyelitis.

Functional and clinical outcomes of limb-sparing therapy for pediatric extremity sarcomas.

PURPOSE: To determine the clinical and functional outcomes of children undergoing limb-sparing therapy for extremity sarcomas. METHODS AND MATERIALS: We retrospectively reviewed 30 patients, age < or = 21 years, who were treated between l979 and l998 with external beam radiotherapy as a component of limb-sparing therapy for primary sarcomas of the extremity at UCSF. Included were patients for whom complete follow-up and functional outcome assessments were available. We assessed the patterns of failure, overall survival, disease-free survival, local control, and limb function. RESULTS: At a median follow-up of 3 years, 12 of the 30 patients recurred: 3 locally, 8 distantly, and 1 with synchronous local and distant disease as site of first progression. Eighteen patients were alive with no evidence of disease. The median overall survival was 10 years, with a median disease-free survival of 8 years. Functional outcome assessment revealed 15 patients retained excellent, 12 good, 1 fair, and 2 poor limb function. CONCLUSION: In pediatric patients receiving limb-sparing therapy, 90% maintained excellent or good limb function without compromising survival, demonstrating the validity of limb preservation in children with extremity sarcomas.

Arthroscopically assisted excision of osteoid osteoma involving the hip.

Two cases of arthroscopically assisted excision of osteoid osteoma involving the femoral neck and acetabulum are presented. This technique allows for percutaneous excision of this benign bone lesion in those rare circumstances when it occurs in an intra-articular location. The approach enables direct visualization of the tumor as well as histologic confirmation. There was minimal morbidity, excellent relief of symptoms, and rapid functional restoration.

Surgical management of innominate giant cell tumor.

The surgical outcome for innominate giant cell tumors was reviewed in 7 patients; 6 (86%) were female patients and 1 (14%) was a male patient. The patients had an average age of 28.7 years (range, 16-42 years) and an average followup of 4.6 years (range, 2.0-7.3 years). Three tumors were in the ischiopubic region, 3 were acetabular, and 1 was iliosacral. The tumors ranged in size from 5 cm x 6 cm to 17 cm x 18 cm. All margins were intralesional. Reconstruction in 3 cases used osteoarticular acetabular allografts. The local recurrence rate was 3 of 7 (43%). Ischiopubic tumors accounted for all recurrences. Vascular invasion was seen in all patients who had a recurrence and only 1 patient without a recurrence. Patients with recurrences underwent subsequent resections and radiation therapy, and remain disease free at an average followup of 3.0 years (range, 0.8-4.2 years) after recurrence. There were no malignant, metastatic, or multicentric recurrences, and no patient died of disease or complications. Innominate giant cell tumor occurs most often in women and is associated with a high risk for local recurrence. Wide margins usually are not possible; intralesional margins are accepted in cases of limited accessibility or potential functional compromise.

Effect of Er:YAG laser holes on osteoinduction in demineralized rat calvarial allografts.

Massive cortical autografts and allografts have been found to incorporate into host bone very slowly and thus are subject to complications such as fatigue fracture and infection. In order to understand and improve the process of osteogenesis in these types of bone grafts, a new experimental model was developed using bone discs from rat calvaria prepared by demineralization and drilling of 0.5 mm diameter holes with a pulsed, 2.94 microns wavelength Erbium:Yttrium-Aluminum-Garnet laser. Four types of bone discs were analyzed: untreated (Type I), demineralized (Type II), laser-ablated (Type III), and laser-ablated then demineralized (Type IV). The discs were transplanted into a subcutaneous site in adult Sprague-Dawley rats and followed for as long as 6 weeks. Histologic analysis of the discs at weekly intervals with use of hematoxylin and eosin staining confirmed the presence of new bone growth in Type-II and Type-IV discs. The amount of new bone growth in each disc was estimated by determining the mineral x-ray attenuation coefficient, which is proportional to mineral density, from digitized radiographs of the discs. The results showed that the processes of demineralization (P < 0.001) and laser ablation with demineralization (p < 0.05) were both significant in enhancing new bone growth in this model. This study demonstrated that osteoinduction can be fostered in cortical bone through the processes of demineralization and laser ablation. To the extent that laser ablation may allow maintenance of structural integrity while altering the surface geometry in such a way as to promote ingrowth of new bone, this experimental model represents an advance in understanding how osteogenesis in cortical bone grafts might be improved.

Giant cell tumor of bone in the foot and ankle.

Giant cell tumor of bone has been shown to behave more aggressively when located in the wrist and hand. Although nearly 4% of giant cell tumors arise in the foot and ankle, biological features specific to this location have not been identified. In our experience with more than 300 cases of giant cell tumor, 12 arose in the foot and ankle and were followed for more than 2 years. These included nine females and three males ranging in age from 15 to 52 years (mean age, 29.5 years). All patients presented with pain of 5.0 months' mean duration and 9 of 12 tumors demonstrated aggressive radiographic features, including bone erosion and destruction; five had either invasion of a joint or a soft tissue mass present. Unlike the hand, where metacarpal and phalangeal lesions are common, no tumors arose in the forefoot and nine of the tumors were present in the ankle region. Four patients were treated with resection (no recurrence), two with curettage and cement packing (one recurrence), and six with curettage and autologous bone graft (two recurrences), which resulted in an overall recurrence rate of 25%. None of the recurrent tumors have returned after additional treatment, which consisted of curettage and cement packing in two cases and resection in one case. Five tumors (four primary, one recurrent) were treated with local resection and reconstruction with no major complications and with no amputations performed. Thus, giant cell tumors of the foot and ankle can be treated with local procedures, which result in recurrence rates similar to those found in more common locations.

Recurrence of giant-cell tumors of the long bones after curettage and packing with cement.

The nine-year experience with sixty patients who had had a giant-cell tumor of a long bone was reviewed to determine the rate of recurrence after treatment with curettage and packing with polymethylmethacrylate cement. The demographic characteristics, including the age and sex of the patient and the site of the tumor, were similar to those that have been reported for other large series. An average of four years (range, two to ten years) after the operation, the over-all rate of initial local recurrence was 25 per cent (fifteen of sixty patients). Patients who had had a tumor of the distal aspect of the radius had a higher rate of recurrence (five of ten) than those who had had a tumor of the proximal aspect of the tibia (seven [28 per cent] of twenty-five) or of the distal part of the femur (three [13 per cent] of twenty-three). Higher rates of recurrence were also noted for patients who had had a pathological fracture (three of six), those who had had a Stage-III tumor according to the classification of Campanacci et al. (six of sixteen), and those who had not had adjuvant treatment with either a high-speed burr or phenol (eight of nineteen). Patients who had had an initial recurrence after packing with cement had a low rate of secondary recurrence when the initial recurrence had been treated with a wide resection or a second intralesional procedure (zero of ten and one of five patients, respectively), after an average of three years (range, ten months to eight years). No patient had a multicentric tumor or metastasis.(ABSTRACT TRUNCATED AT 250 WORDS)