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Biomedical subjects

S R Cannon

Publications and source records attributed to S R Cannon.

At least 37 records · Page 2Linked to original sources
PubMed2004

Dedifferentiated chondrosarcoma: use of MRI to guide needle biopsy.

AIM: To describe the use of MRI to identify and biopsy areas of dedifferentiation in patients with a suspected diagnosis of dedifferentiated chondrosarcoma. MATERIALS AND METHODS: Low-grade chondrosarcoma is characterized at magnetic resonance imaging (MRI) as having a lobulate, hyperintense appearance on T2-weighted spin-echo sequences. T2-weighted MR images were assessed in 15 patients with a final pathological diagnosis of dedifferentiated chondrosarcoma for regions of atypical reduced signal intensity. Information regarding the site of ultrasound or computed tomography (CT)-guided biopsy was available in 10 cases. RESULTS: Nine patients were male and six female with a mean age of 60 years (range 25-77 years). The sites involved were the distal femur (n+4) pelvis (n=3) proximal femur (n=4) femoral diaphysis (n=1) proximal humerus (n=2) and proximal tibia (n=1). The dedifferentiated component consisted of osteosarcoma (n=5) malignant fibrous histiocytoma (n=6) spindle cell sarcoma (n=1) leiomyosarcoma (n=1) and pleomorphic sarcoma (n=1). In 14 of the 15 cases, areas of lower signal intensity lacking in lobulation were identified. In nine of the 10 cases, biopsy site included such areas and yielded high-grade sarcoma. CONCLUSIONS: Dedifferentiation within chondrosarcoma may be identified on T2-weighted MRI as areas of reduced signal intensity. These areas should be the preferred site of biopsy.

Adult↗
PubMed2004

A histomorphological study of tendon reconstruction to a hydroxyapatite-coated implant: regeneration of a neo-enthesis in vivo.

The attachment of tendons and ligaments to massive endoprostheses remains a clinical challenge due to the difficulty in achieving a soft tissue implant interface with a mechanical strength sufficient to transmit the forces necessary for locomotion. We have used an in vivo animal model to study patellar tendon attachment to an implant surface. The interface generated when the patellar tendon was attached to a hydroxyapatite (HA) coated implant was examined using light microscopy and a quantitative histomorphological analysis was performed. In the Autograft Group, the interface was augmented with autogenous cancellous bone and marrow graft, and at six weeks an indirect-like insertion was observed. At twelve weeks, the interface was observed to be a layered neo-enthesis, whose morphology was similar to a normal direct tendon insertion. In the HA Group, the tendon-implant interface was not augmented, and the implant was enveloped by a dense collagenous fibrous tissue. This study shows that a tendon-implant neo-enthesis can develop in situ by employing a suitable implant surface in association with biological augmentation.

Animals↗
PubMed2004

The use of chondrogide membrane in autologous chondrocyte implantation.

UNLABELLED: Autologous chondrocyte implantation is a new technique for the treatment of chondral defects in the knee. The exact procedure involved is continuously being developed with the ultimate aim of achieving hyaline cartilage regeneration. We present the outcome of our series of 31 patients, focussing on the use of the chondrogide membrane in the implantation process. Assessment is presented both in the form of arthroscopic appearance at approximately 1 year, and in the form of clinical outcome measures at 1 year and at 2 years after the second stage of the procedure. CONCLUSION: the use of chondrogide membrane in the fixation of cells during the implantation process is associated with satisfactory clinical outcome and does not appear to show evidence of hypertrophy at one-year arthroscopy, as compared to periosteum.

Adolescent↗
PubMed2003

Osteosarcoma over the age of forty.

The European Musculo Skeletal Oncology Society (EMSOS) has carried out a retrospective review of patients over the age of 40 years with osteosarcoma. 481 patients from 12 centres or multicentric groups were included. 42 patients had osteosarcoma arising in Paget's disease, median survival was 9 months. Patients with axial or metastatic tumours also did badly whilst 41 patients with radiation-induced osteosarcoma had a prognosis paralleling conventional osteosarcoma matched for patient age and site of the tumour. 238 patients had high grade non-metastatic osteosarcoma and had a survival of 46% at 5 years. Older patients had less chemotherapy and fared worse. Osteosarcoma in the elderly is a curable condition and warrants intensive treatment with chemotherapy and surgical resection.

Adult↗
PubMed2003

The effect of component malalignment on the clinical and radiological outcome of the Kinemax total knee replacement.

Component angles of 198 Kinemax total knee replacements were measured from standard short leg radiographs. An ideal tibio-femoral angle of between 4 and 10 degrees of valgus was achieved in 64.6% of patients. After an average follow-up of 6.5 years (range 4.5 to 9.5), there was no significant difference between knees in acceptable and suboptimal alignment in terms of pre- and post-operative knee and function scores and prevalence of radiolucent lines. Varus placement of the tibial component was significantly more common by trainee surgeons (P<0.001).

Aged↗
PubMed2003

The swing procedure for pelvic ring reconstruction following tumour excision.

AIM: High grade periacetabular osteosarcomas extending to the sacro-iliac region present a difficult management problem. We describe our experience of the swing procedure as a method of limb salvage. METHOD: The procedure was performed on three patients with stage II B osteosarcoma. RESULTS: Functional outcome was poor in all three with a mean Musculoskeletal Tumor Society score of 29% (27-30) at last review. All three developed local recurrence and one developed pulmonary metastases. The mean disease free interval post-operatively was 4.7 months (4-6) and they died of their disease at a mean of 10 months (5-16). CONCLUSIONS: This form of limb salvage is technically demanding and carries a high morbidity. Functional outcome is poor and the prognosis for this group of patients is not improved by surgery. Alternative treatment options are discussed.

Adolescent↗
PubMed2002

Functional outcome following excision of tumours of the distal radius and reconstruction by autologous non-vascularized osteoarticular fibula grafting.

The distal radius and its articulations clearly have a vital role in the functional abilities of the hand and wrist. The treatment of tumours of the radius, therefore, needs to achieve satisfactory clearance of the lesions while also preserving as much wrist function as possible. We have employed osteoarticular autologous fibula grafts to reconstitute the distal radius after tumour excision. Since 1992, 13 patients have been treated by this technique for tumours of the distal radius. The group comprised patients with primary and recurrent giant cell tumours of bone, osteosarcoma, chondrosarcoma and Ewing's tumour. This technique achieves a satisfactory functional result without compromise of the prognosis for the tumour.

Adult↗
PubMed2002

Surgical outcomes in osteosarcoma.

From the European Osteosarcoma Intergroup study 202 patients were assessed with respect to their surgical treatment. Although treated in three different centres the survival of the three groups was identical (57% at five years). Two of the centres had rates of limb salvage of 85% and 83%, respectively, while the third had a rate of 49%. The corresponding risks of local recurrence were 13.3%, 6.8% and 2.5%, with all local recurrences arising in limbs with attempted limb salvage. Local recurrence was closely related to the adequacy of the margins of excision and to the chemotherapeutic response. Patients who had undergone limb-salvage surgery and who developed local recurrence still had a better survival than those who had primary amputation (37% v 31% survival at five years). Of patients who relapsed, 31% of those with local recurrence alone were cured by further treatment, as compared with only 10% of those with metastases. Limb-salvage surgery with effective chemotherapy remains the optimum treatment for osteosarcoma.

Adolescent↗
PubMed2001

The effect of local recurrence on survival in resected osteosarcoma.

The aim of this study was to assess the effect of local recurrence on survival in primary osteosarcoma. 559 patients entered into two randomised trials of the European Osteosarcoma Intergroup who received surgery for primary operable high-grade osteosarcoma of the extremities were included in this analysis. Proportional hazards modelling techniques were used to assess the relative importance of sex, age, site, surgery performed and local recurrence. The last of these was considered as a time-dependent covariate. 42/559 (8%) patients had a local recurrence. In the multivariate analysis, local recurrence was found to greatly increase the risk of death (hazard ratio (HR)=5.10, 95% confidence interval (CI) 3.51-7.41). Site and surgery performed also had a significant influence within this model. Using the technique of landmark analysis, with the landmark time set at 18 months, local recurrence alone had a significant influence on survival (HR=4.60, 95% CI 2.80-7.57). Local recurrence is an indicator of poorer survival for patients with operable primary osteosarcoma.

Adolescent↗
PubMed2001

The Kinemax total knee arthroplasty. Nine years' experience.

We reviewed the outcome of 422 primary cemented Kinemax total knee arthroplasties implanted into 369 patients over a period of five years, from January 1989. The operations were carried out at two NHS district general hospitals and one teaching hospital by 31 surgeons. During the period of review, 49 patients died and ten knees were lost to follow-up (68 knees). The mean Knee Society score improved from 28 before to 89 after surgery, and the mean function score increased from 23 to 79. The range of flexion improved from 92 degrees to 105 degrees. These improvements were maintained throughout the period of study. At the latest review radiolucent lines of 1 mm were seen around 15% of tibial components, 1.4% of patellar components and 9.5% of femoral components. In no case were these changes progressive. Using revision as the endpoint, cumulative survival was 99% after five years and 96.95% after nine years. All revisions were undertaken for deep infection or secondary trauma. Our study has shown that the Kinemax total knee replacement, when carried out with retention of the posterior cruciate ligament by surgeons of varying experience, produces very satisfactory results in the medium term.

Aged↗
PubMed2000

Malignant round cell tumours of bone: atypical clinical and imaging features.

OBJECTIVE: To describe the clinical, radiological and MRI features of six atypical cases of histologically proven appendicular Ewing sarcoma/primitive neuroectodermal tumour (PNET). DESIGN: Retrospective review of case notes and available imaging was carried out. PATIENTS: Six patients (4 male, 2 female; mean age 27 years, range 19-44 years), presenting over a 77-month period, were identified from the Bone Tumour Register. All had unusual clinical and imaging features for Ewing sarcoma/PNET. RESULTS AND CONCLUSIONS: Four tumours were centred on the distal femoral metaphysis, one in the proximal tibial metaphysis and one in the distal tibial metaphysis. Plain radiographs were available in four cases and showed minor cortical changes. MRI demonstrated a relatively small, eccentrically located intraosseous component with a large, eccentric extraosseous component. Extension into the epiphysis was seen in three cases and into the adjacent joint in two cases. Intraosseous "skip" metastases were present in three cases. The clinical and imaging features were atypical for conventional intraosseous Ewing sarcoma/PNET and the exact site of origin (intraosseous, periosteal or soft-tissue) was unclear.

Adult↗
PubMed2000

An audit of MRI for bone and soft-tissue tumours performed at referral centres.

AIM: Magnetic resonance imaging (MRI) is essential in the pre-operative staging of suspected primary bone and soft-tissue sarcomas. Such lesions are ideally managed in specialist centres but it is becoming increasingly common for patients to undergo MRI before referral. The aim of this study was to assess the adequacy of such studies. MATERIALS AND METHODS: Fifty patients (30 men, 20 women; mean age 39 years, range 9-89 years) were included over a 1-year period. Tumours included 31 suspected primary bone tumours and 19 soft-tissue tumours. RESULTS: The total number of sequences used was 225 (mean 4, range 2-8). Enhancement was used in 19 cases. The commonest mistake was the failure to image the whole bone for 'skip' metastases in 50% of appropriate cases (high-grade malignant lesions of bone). Reports were available in 40 cases. Specific information regarding precise intraosseous and extraosseous extent of tumour and relationship to the neurovascular bundle and adjacent joint was commonly not included. CONCLUSIONS: This audit indicates that a greater awareness is needed amongst general radiologists of the MR imaging and reporting requirements for musculoskeletal tumours. In particular, all important axial imaging is sometimes omitted.Saifuddin, A. (2000). Clinical Radiology 55, 537-541.

Adolescent↗
PubMed2000

A functional analysis of massive knee replacement after extra-articular resections of primary bone tumors.

We performed a functional analysis of massive knee replacements after extra-articular resection of primary bone tumors. Patients did not score as highly on the Musculoskeletal Tumour Society Score and Knee Society Score (P < or = .01) as patients who had undergone intra-articular resection. Lower scores were achieved for emotional acceptance (P < or = .01), functional restriction (P < or = .05), walking distance (P < or = .05), and managing stairs (P < or = .05). These patients had a significantly greater extension lag (P < or = .01) and greater fixed flexion (P < or = .05). This functional deficit is primarily due to a compromised extensor mechanism inherent in the type of surgical resection necessary to achieve adequate removal of the tumor.

Adolescent↗
PubMed2000

Cementless fixation for primary segmental bone tumor endoprostheses.

To combat the high incidence of aseptic loosening for young patients and for patients with failed implants after resection for bone tumors, intramedullary cementless fixation of massive tumor implants was investigated. These implants consist of a hydroxyapatite coated titanium stem. To date, 47 of these prostheses have been inserted for the treatment of primary bone tumors. Radiographs indicate that the stems are osseointegrated. Radiolucent lines have not been seen between the implant and the bone. Bone remodeling changes have been observed. In several cases in which the implant was not seated properly on the transaction site, bone grew to the shoulder of the implant. Bone remodeling was particularly evident in stems that were coated over their entire surface. In these cases, the implant induced local bone resorption so that the bone around the midstream region became thinner, with resorption of cortical bone on the periosteal surface and maintenance of bone on the endosteal surface adjacent to the stem. This effect was attributed to stress shielding, and a three-dimensional finite element model using loading data obtained from a telemetry study indicated that, where the stem was bonded to the bone over the entire surface, stresses in the outer cortex became reduced. In the finite element model, reducing the region of hydroxyapatite coating to approximately 1/3 of the stem length reduced the extent of the low-stress area in the outer cortex. Subsequently, prostheses have been coated with hydroxyapatite over only approximately 1/3 of their stem. This method of fixing the massive endoprosthesis to the bone is thought to be successful in the short-term and offers an alternative to cemented fixation.

Bone Neoplasms↗
PubMed1999

Design and application of combined hip-knee intramedullary joint replacements.

Cases in which there is a total hip arthroplasty and a stemmed total knee arthroplasty in the same femur, with loosening of 1 or both components, with serious endosteal bone loss or even a fracture between the stems present a difficult reconstruction problem. We describe a reconstruction using a combined hip and stemmed knee, designed so that they could be rigidly connected during the surgical procedure. The advantages of this implant design are that the entire femur with its muscle attachments is preserved, and the inherent stability allows for immediate weight bearing. To determine the viability of the connection between the hip and the knee, a stress analysis was carried out using finite element analysis. Guidelines were thus provided for the required metal and cement thicknesses. Three case examples are presented with an average follow-up of 3 years. It was shown that the combined hip-knee implant could provide successful results for these difficult reconstructive problems in appropriately selected cases.

Adult↗
PubMed1999

Neoadjuvant chemotherapy with doxorubicin and cisplatin in malignant fibrous histiocytoma of bone: A European Osteosarcoma Intergroup study.

PURPOSE: Studies involving small case series have suggested that malignant fibrous histiocytoma of bone (MFH-B) is a chemosensitive tumor and that chemotherapy may improve survival. In this study, we evaluated clinical and pathologic response rates and survival in a series of patients treated with a consistent chemotherapy regimen of doxorubicin and cisplatin (DOX/DDP). PATIENTS AND METHODS: Study patients were required to have biopsy-proven MFH-B, no previous chemotherapy, and primary or metastatic measurable disease and to be </= 65 years of age. Treatment consisted of doxorubicin 25 mg/m(2)/d days 1 through 3 and cisplatin 100 mg/m(2) by 4-hour intravenous infusion every 3 weeks for six cycles. In patients with operable primary tumors, chemotherapy was planned to start within 42 days of biopsy, with definitive surgery performed after three cycles. RESULTS: Forty-one patients had operable nonmetastatic limb sarcomas, and 23 (56%) completed six chemotherapy cycles. Limb salvage was possible in 33 patients (80%), and 16 (42%) of 38 assessable specimens showed a good pathologic response (>/= 90% necrosis). Median time to progression was 56 months, and the 5-year progression-free survival rate was 56% (95% confidence interval [CI], 40% to 72%). Median survival time was 63 months, and the 5-year survival rate was 59% (95% CI, 41% to 77%). Patients with a good pathologic response had longer survival times and times to progression than did those with a poor response. Also treated were two patients with locally recurrent and nine with metastatic disease, and these patients had a median survival time of 17.5 months. CONCLUSION: Our study suggests that adjuvant or neoadjuvant chemotherapy with DOX/DDP is beneficial in MFH-B. Good pathologic response rates and survivals are quite comparable with those for osteosarcoma, a related bone tumor for which adjuvant or neoadjuvant chemotherapy is an accepted practice.

Adolescent↗
PubMed1998

The forces in the distal femur and the knee during walking and other activities measured by telemetry.

The forces and moments in the shaft of a distal femoral replacement were measured by telemetry for a subject during different activities, and calculations were then made of the forces at the knee. The axial force showed a small peak at heel-strike followed by two main peaks during stance. In level walking, the peak axial force was between 1,487 and 1,718 N (2.2-2.5 BW), the peak shear force was 269-368 N (0.4-0.54 BW) directed anteriorly on the tibia, the peak axial torque was 7 Nm internal, while the patellofemoral force was 466-571 N. The highest axial force was recorded for descending stairs (2.8 BW). Standing on one leg produced 2.4 BW, while lying supine and raising the leg produced 1.7 BW. The data produced may resemble that of a normal subject, and has application to basic joint mechanics, to joint reconstruction, and to total knee replacement design and evaluation.

Adult↗