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Biomedical subjects

F H Sim

Publications and source records attributed to F H Sim.

At least 73 records · Page 4Linked to original sources
PubMed1996

Multicentric chondrosarcomas.

Multicentric chondrosarcomas, other than those from mesenchymal chondroma, are rare and difficult to differentiate from metastatic disease. Eight new patients with multicentric chondrosarcomas are reported. Five patients had chondrosarcomas that were monomelic, 3 had disseminated chondrosarcomas, 3 had synchronous involvement, and 5 had metachronous involvement; 1 patient had Ollier's disease. A bimodal age distribution was apparent: 4 patients were between 62 and 76 years old, and the remaining 4 were between 16 and 33 years old. Average duration of followup was 6 years, 4 months. Each of the patients with synchronous chondrosarcomas had single bone lower extremity involvement and presented with symptoms occurring at only 1 of the 2 sites of tumor. Each of the 5 patients with metachronous chondrosarcomas experienced involvement of a different bone when the second tumor presented. Only 1 of these metachronous chondrosarcomas was limited to the lower extremity. The second tumor occurred in all patients after excellent control of the primary tumor by wide excision. The average duration between diagnosis of the 2 tumors was 4 years, 4 months (range, 8 months-12 years, 9 months). Patients who had nonmonomelic malignancies must be viewed with a considerably more guarded prognosis than those who had monomelic chondrosarcoma because each of the 2 deaths resulting from progressive disease occurred among the 3 patients with nonmonomelic chondrosarcoma. The nonmonomelic malignancies may represent metastatic chondrosarcoma with a rare predilection to bony involvement. Monomelic chondrosarcoma simply may represent lesions analogous to the skip lesions observed in osteosarcoma.

Adolescent↗
PubMed1996

Limb salvage for neoplasms of the shoulder girdle. Intermediate reconstructive and functional results.

The intermediate functional results were assessed for fifty-seven patients who had had a limb-salvage procedure for treatment of a tumor of the shoulder girdle region at our institution from 1980 through 1990. Fifty-three patients had a malignant bone tumor (a sarcoma) and four had an extensive giant-cell tumor. The resections were classified according to the system of the Musculoskeletal Tumor Society. A variety of reconstructive procedures were performed after resection of the tumor, with the choice of procedure depending on the type of resection and the needs of the patient. The functional results were described and graded quantitatively according to the functional rating system of the Musculoskeletal Tumor Society. The average duration of follow-up was 5.3 years (median, 4.6 years) for the forty-seven patients who were still alive at the time of the latest follow-up examination. Eight patients died of disease and two others died of unrelated malignant tumors an average of 1.8 years postoperatively. The resection of the tumor was classified as wide in forty of the fifty-three patients who had a sarcoma and as marginal in thirteen; four patients had local recurrence (two, after a wide resection, and two, after a marginal resection). One of the four patients who had a giant-cell tumor had local recurrence. The functional results were related to the type of resection and the method of skeletal reconstruction. After resection of the entire scapula and the proximal aspect of the humerus, reconstruction with a spacer frequently resulted in asymptomatic superior subluxation of the implant and poor function of the shoulder. After extra-articular resection of the glenoid cavity and the proximal aspect of the humerus with loss of the abductor mechanism, osseous arthrodesis resulted in good function that was superior to that found after reconstruction with a spacer or a proximal humeral replacement prosthesis. Our preferred method to achieve fusion was insertion of an intercalary allograft and a vascularized fibular graft. However, the allograft fractured in three of four patients in whom primary fusion had been obtained with this technique. An osteoarticular allograft inserted after intra-articular resection of the proximal aspect of the humerus and preservation of the abductor mechanism provided good function that was superior to that found after reconstruction with a proximal humeral replacement prosthesis, which produced symptomatic instability that led to a secondary arthrodesis in some patients. However, subchondral fracture and collapse of the osteoarticular allograft occurred in four of eight patients by the time of the latest follow-up examination. The results of all methods of reconstruction were satisfactory with regard to pain, emotional acceptance, and manual dexterity. We believe that the use of a method of reconstruction that is appropriate with regard to the needs of the patient and preoperative counseling regarding the expected functional level and restrictions of activity are critical for a high level of postoperative satisfaction.

Adolescent↗
PubMed1996

Megaprostheses after resection of distal femoral tumors. A rotating hinge design in 30 patients followed for 2-7 years.

Between 1981-1993, we inserted 32 Kinematic Rotating-Hinge Knee tumor prostheses in 30 patients, of which 2 concerned revisions of the same type of prosthesis. The diagnoses were 21 osteosarcomas, 2 chondrosarcomas, 2 Ewing's sarcomas, 2 metastatic breast carcinomas, 1 multiple myeloma, 1 giant cell tumor and 1 Gorham's disease. The median age was 25 (12-60) years and the median follow-up for survivors was 3.5 (2-6.6) years. There were 7 metastases and 1 local recurrence. 20 knees had excellent (MSTS) scores for motion (median flexion 120 degrees), 8 had good (84 degrees) and 4 had fair (45 degrees). The overall function was excellent in 6 cases, good in 14, fair in 9 and poor in 3. The radiographic assessment (ISOLS) gave "excellent" or "good" scores in 27 knees for bone remodelling, 31 for the interface, 28 for the anchorage, 31 for the implant body and 30 for the articulation. Extracortical bone bridging greater than 25% was observed in 18 of 27 prostheses.

Adolescent↗
PubMed1996

Ewing's sarcoma of the proximal femur.

The cases of 16 patients with Ewing's sarcoma of the proximal femur treated in the era of multiagent chemotherapy were reviewed, with emphasis on the mechanical problem of tumor involvement in this structurally demanding site. Fourteen patients received chemotherapy and local radiotherapy as the initial primary treatment. One patient had chemotherapy and radiotherapy, followed by wide local resection. One patient had amputation, followed by chemotherapy, for pathologic fracture and extensive soft tissue involvement at presentation. Two local recurrences occurred. Excluding the 2 patients whose femurs were fixed prophylactically, the pathologic fracture rate was 79%. In addition, by excluding the 2 patients who died before fracture, the pathologic fracture rate was 92%. Nonunion occurred in 5 (71%) of the 7 pathologic fractures not treated by resection and required as many as 5 additional surgical procedures to obtain union. At latest followup evaluation (average, 6.3 years), 10 patients had no evidence of disease, 1 was alive with disease, and 5 had died of their disease. Options for management should include primary resection and reconstruction or prophylactic internal fixation after completion of chemotherapy plus or minus radiotherapy.

Adolescent↗
PubMed1996

Ewing's sarcoma.

Ewing's sarcoma is the second most common primary malignant bone tumor of children. Tremendous strides in the multidisciplinary treatment of Ewing's sarcoma have been made over the past 25 years. Aggressive chemotherapy has increased the 5-year survival rates from 10% to over 70%. The role of surgery for local control has gained importance. These advances in the diagnosis, staging, and treatment of Ewing's sarcoma are discussed in detail.

Bone Neoplasms↗
PubMed1996

Osteoblastoma.

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Adolescent↗
PubMed1995

Parosteal osteoma of bones other than of the skull and face.

BACKGROUND: Osteoma of the skull and facial bones is not uncommon, is usually asymptomatic, and may be associated with Gardner's syndrome. Osteomas involving other bones are unusual. METHODS: The authors describe 14 cases (eight men and six women from age 21-66 years) of parosteal osteoma of bones other than of the skull and face. RESULTS: Thirteen lesions involved long bones, and one involved the clavicle. A long-standing (18 months to 31 years) mass was reported in seven patients. Symptoms of pain, a mass, or both were present in all except three patients who were asymptomatic. Lesions ranged from 2.5 to 20 cm in greatest dimension. Histologically, they blended with the cortex, did not infiltrate the medullary cavity, and consisted of dense sclerotic lamellar bone with haversian systems, similar to the architecture of normal cortical bone. There was no spindle cell proliferation. Nine patients underwent resection, four had biopsy, and one had debulking. With a follow-up of 1-23 years, no recurrence or metastasis was reported. CONCLUSIONS: Parosteal osteoma must be distinguished from parosteal osteosarcoma, a low grade malignant neoplasm. If radiographs do not identify areas of radiolucency and sections do not contain spindle cells, the diagnosis of parosteal osteoma is justified.

Adult↗
PubMed1995

Survival after pulmonary metastasectomy in soft tissue sarcoma. Prognostic factors in 214 patients.

This retrospective study examines prognostic factors for post-metastasectomy survival in soft tissue sarcoma patients. Between 1976 and 1992, 274 consecutive patients (median age 49 [7-96] years) with pulmonary metastatic soft tissue sarcoma of the extremity or trunk wall (31 at presentation) were managed at the Mayo Clinic. 214 underwent pulmonary metastasectomy and 163 of these also received adjuvant chemotherapy. There were 195 local excisions, 14 lobectomies, and 5 pneumonectomies. 90 patients had solitary metastases, 184 patients had 2 or more metastases. 31% of patients had MFH tumors and 88% of all tumors were high grade. Median follow-up for survivors was 8 (2-21) years. 5-year overall survival after metastasectomy was approximately 40% (cf. 20% for non-metastasectomy). Age > 50, MFH tumors, > or = 2 metastases, metastasis size > 2 cm, metastasis-free period < or = 18 months, and the use of adjuvant chemotherapy were univariately unfavorable factors. Size of metastasis > 2 cm, number of metastases > or = 2, and metastasis-free interval < or = 18 months were independently unfavorable for survival. In a prognostic system, patients with 0 risk factors had a 60% 5-year survival, those with 1, 2, or 3 of these factors had 30%, 20% and 0% survival, respectively.

Adolescent↗
PubMed1995

Osteosarcoma of the diaphysis of long bones: clinicopathologic features and treatment of 51 cases.

Of 1000 osteosarcoma cases recorded in the Mayo Clinic records, approximately 7% of the lesions occurred in the diaphysis of long bones, mostly in the femur, tibia, and humerus. The average age of the patients with these lesions was 28 years (range: 8 to 67). The duration of their symptoms before diagnosis was greater than that for patients with conventional osteosarcoma in the metaphysis. In approximately 20% of the cases, the radiographic appearance mimicked that of Ewing's sarcoma. Amputation surgery was the major form of treatment. The 2-, 5- and 15-year survival was 42%, 29%, and 20%, respectively.

Adolescent↗
PubMed1995

Ewing's sarcoma.

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Antineoplastic Agents↗
PubMed1995

Participation in sports after hip and knee arthroplasty: review of literature and survey of surgeon preferences.

OBJECTIVE: To summarize previously published findings and to present the opinions of a group of reconstructive orthopedic surgeons from a single institution on participation in sports after hip or knee arthroplasty. DESIGN: We reviewed the literature pertaining to participation in sports after hip or knee arthroplasty and surveyed a group of orthopedic surgeons about their recommendations for resumption of various sports activities by patients who had undergone total hip or knee arthroplasty. MATERIAL AND METHODS: A computerized literature search was performed, and salient issues about participation in sports after joint replacement procedures were synthesized. At the Mayo Clinic, 28 orthopedic surgeons (13 consultants and 15 fellows or residents) completed a single-page questionnaire that requested a recommendation ("yes," "no," or "depends") about patients resuming participation in 28 common sports after recovery from total hip or knee arthroplasty. Staff surgeon responses were compared with responses from fellows and residents by using the Mann-Whitney U test. Sports in which 75% of surgeons would not allow participation were identified as "not recommended," whereas sports in which 75% of surgeons would allow participation were labeled as "recommended." RESULTS: Fellows and residents were less likely than staff surgeons to allow return to cross-country skiing after total knee arthroplasty. Otherwise, responses from consultant surgeons and from fellows and residents did not differ significantly. Recommended sports included sailing, swimming laps, scuba diving, cycling, golfing, and bowling after hip and knee replacement procedures and also cross-country skiing after knee arthroplasty. Sports not recommended after hip or knee arthroplasty were running, waterskiing, football, baseball, basketball, hockey, handball, karate, soccer, and racquetball. CONCLUSION: After hip or knee arthroplasty, participation in no-impact or low-impact sports can be encouraged, but participation in high-impact sports should be prohibited.

Hip Prosthesis↗
PubMed1995

Computer-aided preoperative planning in knee osteotomy.

It has been demonstrated that osteoarthritis (OA) is activity related and may worsen when joint contact stress becomes excessive due to overloading. Hence, joint alignment and loading are considered to be the key biomechanical determinants for OA. The initiation of pathologic changes in the knee has been described by the mechanism termed, "vicious cycle" in which joint axial malalignment creates excessive stresses to the localized joint cartilage/subchondral bone regions and the surrounding soft tissue which in turn produces more laxity and joint deformity and thus repeats the cyclic degradation mechanism. If this degenerative cycle can be broken with joint alignment surgery such as osteotomy, a procedure to realign the knee joint and thus redistribute joint forces applied to each compartment, performed properly and at the appropriate time, the osteoarthritic disease process can be decelerated and even reversed. The main goals of this paper are to emphasize the importance of accurate preoperative planning for osteotomy in order to properly correct joint alignment, and to justify the application of an existing computer program, OASIS (Osteotomy Analysis and Simulation Software) using plain radiographs to perform appropriate surgical planning. Normal subjects and knee osteotomy patients were studied to establish a database for the purpose of establishing the utility and efficacy of the presently proposed concept. We wish to rationalize knee osteotomy as a preferred and cost-effective treatment for patients with early symptoms of OA in the knee. This paper presents a new concept of preoperative planning for knee osteotomy based on the underlying etiology of the disease and biomechanical viewpoint with strong emphasis on surgical treatment rationales. The established principles in this paper can be applied to other joints of the body and will help implement preventive measures and other non-surgical means to manage patients with axial malalignment or early degenerative changes.

Algorithms↗
PubMed1995

Orthopaedic management using new devices and prostheses.

The goals of treatment for patients with metastatic disease are control of pain and maintenance of function. Prosthetic arthroplasty is a useful technique for selected indications. Specific indications include (1) reconstruction of large destructive areas that are not amenable to internal fixation, (2) salvage of failed internal fixation devices, and (3) salvage of lesions in which there are no radiotherapy options to prevent disease progression. Custom modular devices allow resection of varying segments of the skeleton. Immediate rigid fixation is achieved with cemented intramedullary stems. Patients are allowed to bear full weight as tolerated immediately postoperatively. A custom modular diaphyseal segmental replacement system allows resection of large diaphyseal lesions and immediate fixation. The complication rate is low after arthroplasty.

Bone Neoplasms↗
PubMed1995

Long-term results of proximal femoral replacement for non-neoplastic disorders.

We reviewed retrospectively 50 consecutive total hip arthroplasties with proximal femoral replacement prostheses in 49 patients. All the patients had massive bone loss. There were 31 women and 18 men who had undergone a mean of 3.1 hip operations. At the last review, 15 patients had died and two had been lost to follow-up, so that 32 patients (33 hips) were available for assessment. The mean age of the patients at the time of the operation was 60.6 years. The mean length of clinical follow-up was 11.1 +/- 4 years, and mean radiographic follow-up was 7.6 +/- 3.2 years. The average preoperative Harris hip score was 46 +/- 13 points, which improved to 80 +/- 10 points after one year and to 76 +/- 16 points at the latest follow-up. The most frequent complication was dislocation, which occurred in 11 hips. Four femoral components and seven acetabular prostheses were revised because of aseptic loosening. With revision at the end point, survivorship after total hip arthroplasty with a proximal femoral replacement prosthesis was predicted to be 64% at 12 years. Although our preliminary results of hip salvage with a proximal femoral replacement prosthesis were encouraging, a longer follow-up has shown a higher rate of failure.

Adult↗
PubMed1994

Malignancies in fibrous dysplasia.

BACKGROUND: Malignancies in fibrous dysplasia are rare. Most cases have been published as single case reports. The role of radiation therapy in the occurrence of sarcoma in fibrous dysplasia is still controversial. METHODS: The Mayo Clinic files were reviewed, including Mayo Clinic cases and consultation cases, to collect all cases of sarcomas arising in fibrous dysplasia. RESULTS: Among 1122 cases with a histologic diagnosis of fibrous dysplasia, 28 cases of sarcoma were found. These 28 cases included 16 Mayo Clinic cases and 12 consultation cases. The sarcomas occurred in 19 cases of monostotic fibrous dysplasia and 9 cases of polyostotic disease (only 1 of Albright's syndrome). The most common histotype was osteosarcoma (19 cases), followed by fibrosarcoma (5 cases), chondrosarcoma (3 cases), and malignant fibrohistiocytoma (1 case). Of the 28 patients, 13 (46%) had received radiation therapy before the sarcoma developed. Most of these sarcomas occurred in the craniofacial bones (13 cases) or in the proximal femur (7 cases), followed by the humerus, pelvis, tibia, and scapula. CONCLUSIONS: Prognosis was poor. Sarcomas may arise with or without radiation. Early diagnosis and adequate treatment may lead to improved prognosis.

Adolescent↗