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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

Fracture of the patella after total knee arthroplasty.

Patellar fracture after knee arthroplasty was found in 11 patients (12 knees) during a 15-year period. Causes of this fracture include trauma, technical factors, and biophysical factors. The incidence of this infrequent complication was significantly increased after patella resurfacing and revision arthroplasty. Minimally displaced, non-comminuted fractures were immobilized, whereas displaced, comminuted fractures with loose patellar prostheses were treated operatively. At a mean follow-up period of 28 months, the average knee score was 75 points. The average arc of motion was 87 degrees, and six of the 11 patients have returned to their prefracture functional level. Treatment should be individualized on the basis of fracture displacement, comminution, and button fixation.

Adult

Liposarcoma of the musculoskeletal system.

Two hundred eleven cases with the diagnosis of liposarcoma of the musculoskeletal system were reviewed. The mean age at diagnosis was 52.9 years. The primary site was the proximal lower extremity in 52%. Myxoid-type liposarcoma was most frequent (60%). Metastasis was observed in 45%. One hundred two patients without prior treatment or distant spread at diagnosis were studied separately. Recurrence was noted in 26%. The median survival time was 7.5 years, with a 5-year survival of 59% and a 10-year survival of 45%. Significant variation in survival time was related to histologic grade, Enneking's stage, tumor size, and histologic type.

Adolescent

Musculoskeletal injuries in competitive swimmers.

Competitive swimming is a rigorous sport being engaged in by an increasing number of young athletes. In swimmers, shoulder pain is the most common musculoskeletal complaint and is usually due to supraspinatus or biceps tendinitis. Glenohumeral instability (often multidirectional) can also be a cause of shoulder pain in swimmers and may be more common than has been reported. Surgical treatment is seldom indicated. Physical therapy modalities and training modifications are the mainstay of treatment. Medial knee pain in breaststroke swimmers and extensor tendon inflammation over the dorsum of the foot are less common injuries and respond to conservative therapy. These overuse syndromes are best prevented by proper training schedules, strength training, flexibility exercises, and avoidance of errors in stroke technique. The rehabilitation program for a competitive swimmer should be chosen with an understanding of the goals of the swimmer and the cooperation of the coach.

Athletic Injuries

Vascularized bone transfer for limb salvage and reconstruction after resection of aggressive bone lesions.

At our institution from 1980 to 1985, 30 patients underwent resection of malignant or locally aggressive bone tumors, with limb salvage and reconstruction by free vascularized bone grafts. Of the 26 patients followed up for at least four months (average, 21 months), four had complications. In these four, there were three nonunions, two infections, and one stress fracture. The average duration of immobilization was 7.6 months in the lower extremity, five months in the pelvis, and 3.8 months in the upper extremity. The average time to union was 6.3 months in the lower extremity, five months in the pelvis, and five months in the upper extremity. Although the technique of oncologic reconstruction must be individualized, our experience indicates that vascularized bone grafts offer significant advantages over conventional methods in selected patients.

Adolescent

Liposarcoma of the soft tissues.

A case report presents a liposarcoma of the extremities and an overall review of this disease entity. Past and present histologic classifications of liposarcoma are discussed, as are the clinical behavior and treatment options in relation to the surgical stage of the tumor. The importance of a well-planned biopsy site is stressed.

Adult

Musculoskeletal oncology: state of the art.

The outlook for the patient with sarcoma of the musculoskeletal system has improved dramatically because of recent advances in diagnosis and treatment. These new developments, as discussed in this review, allow greater success in achieving the goals of treatment, which include 1) control of the primary lesions, 2) maintenance of function, and 3) long-term survival.

Bone Neoplasms

Reconstruction of musculoskeletal defects about the knee for tumor.

One of the most challenging problems of limb salvage is a large tumor involving the knee joint. Since 1970, 79 patients, ranging in age from 14 to 74 years (mean, 27 years), have had reconstruction of the knee after en bloc resection of a primary bone tumor. Sixty-one patients had lesions involving the distal femur, with a mean resection length of 13.5 cm, and 18 patients had lesions involving the proximal tibia, with a mean resection length of 10.5 cm. Thirty-nine patients had malignant lesions, of which osteosarcomas predominated, and 40 patients had benign tumors, of which giant cell tumors were the most prevalent. Reconstruction was done with a custom total knee arthroplasty in 41 patients, a resection arthrodesis in 27, and an allograft in 11. The functional results were graded according to the rating system devised by the Musculoskeletal Tumor Society. of the patients with resection arthroplasty, 70% had a good or excellent rating, although ten required revision. Of the patients with resection arthrodesis, 74% had a good or excellent rating, as did 55% of the patients with osteochondral allografts. When a limb salvage procedure is done, careful consideration must be given to the type of procedure chosen to reconstruct the knee. This decision is based on a number of factors related to the tumor and the patient. Although these various procedures promise functional restoration, the reconstructive procedure should be individualized and designed to meet the needs of the patient.

Adolescent

Primary malignant bone tumors of the shoulder girdle: surgical technique of resection and reconstruction.

Limb ablation for tumors of the shoulder is a devastating procedure. Recent advances in preoperative investigative measures, adjuvant chemotherapy, and reconstructive techniques have resulted in an increased interest in limb-sparing resection. For limb-sparing procedures to present a viable alternative in these cases, recurrence rates must be comparable to those obtained with ablative surgery. In addition, the resection must result in an improvement over the status obtainable with prosthetic devices. Twenty-four patients underwent limb-salvage procedures of various forms for primary bone tumors of the shoulder girdle. At follow-up (average: 33 months), 19 patients were alive without disease, one was alive with disease, and four were dead. One patient had local recurrence. All surviving patients enjoyed nearly normal function of the distal extremity. Improvements in techniques of soft tissue reconstruction in an effort to gain function and stability after wide resection of these tumors are necessary. Results indicate that these limb-salvage attempts offer successful alternatives to mutilating and crippling proximal amputations of the upper extremity.

Adolescent

Fibular reconstruction for giant cell tumor of the distal radius.

The management of giant cell tumors involving the distal radius has always been a difficult problem. After resection to eradicate a primary or recurrent lesion, transplantation of a nonvascularized fibular autograft was used in 12 patients. Of these patients, ten had good to excellent functional results. The procedure can restore a functionally useful wrist.

Adult

Total hip arthroplasty in Paget's disease. A follow-up note.

In eighty patients who were seen with Paget's disease of the hip between 1969 and 1982, symptomatic coxarthrosis led to total hip arthroplasty in ninety-one hips. The long-term clinical and radiographic results were analyzed by use of the Mayo Clinic hip-scoring system. The cases of the forty-six patients (fifty-two hips) who had been operated on before 1975 were analyzed ten years after the arthroplasty. In this group, the incidence of aseptic loosening that required revision was approximately 15 per cent; radiographic evidence of loosening was evident in approximately 30 per cent of the femoral components and approximately 14 per cent of the acetabular components. Actuarial analysis comparing these forty-six patients with our over-all experience of total hip arthroplasty during the same period of time in 7,222 hips of patients who did not have Paget's disease revealed an increase of slight statistical significance in the incidence of revision for aseptic loosening in the patients who had Paget's disease. However, the over-all result was good or excellent in 74 per cent of these patients, suggesting that replacement of the hip using cemented components remains an acceptable form of treatment for degenerative coxarthrosis secondary to Paget's disease.

Aged

Lymphadenectomy in the management of stage I malignant melanoma: a prospective randomized study.

A prospective randomized study was initiated at our institution in 1972 to determine the efficacy of routine elective lymphadenectomy in localized (stage I) melanoma. Included in the study were 171 patients, 62 of whom had no lymphadenectomy, 55 of whom had delayed lymphadenectomy, and 54 of whom had immediate lymphadenectomy. No significant difference was found among the three treatment groups with respect to survival or metastasis-free survival. Multifactorial analysis indicated that the level of invasion and the thickness of the lesion were the most important prognostic factors, followed by age (60 years or older), site (legs), and tumor type (nodular). A prognostic index based on these variables was highly predictive of metastasis or death. Even when this score was considered, no significant variation was noted among the three treatment groups. More subsequent complications of melanoma, however, occurred in the group with no lymphadenectomy--36 in this group but only 19 in each of the other treatment groups. This finding was not statistically significant but does indicate that a few additional problems may be associated with leaving regional nodes intact. Further studies are needed, and indeed are being conducted, to determine whether elective lymphadenectomy improves survival sufficiently to offset the costs and the complications associated with this approach.

Adult

Acute fractures of the femoral neck managed by total hip replacement.

The criteria for the management of patients with femoral neck fractures by internal fixation, hemiarthroplasty, or total hip replacement are becoming better defined. Our experience in 111 cases indicates that total hip arthroplasty has a definite role if the cases are carefully selected. The main indication is a high-risk fracture in an elderly patient with associated pre-existing joint disease.

Acute Disease

Dedifferentiated chondrosarcoma. A report of the clinicopathological features and treatment of seventy-eight cases.

Dedifferentiated chondrosarcoma is a highly malignant variant of chondrosarcoma. Approximately 11 per cent of chondrosarcomas can be expected to dedifferentiate into more anaplastic lesions. In this report, we analyze the clinicopathological features and treatment of seventy-eight lesions of this type. The ages of the patients ranged from nineteen to eighty-two years (average, 54.6 years). The cartilaginous precursor was central in most patients. Eleven of the lesions developed in the site of a previously resected low-grade chondrosarcoma. Dedifferentiation was from low-grade chondrosarcoma to osteosarcoma in forty-two patients, to fibrosarcoma in thirty-three, and to malignant (fibrous) histiocytoma in three. Perforation of the cortex and a soft-tissue mass were found in most of the patients. Widespread metastatic disease within two years after resection was a frequent finding. The over-all five-year-survival rate was 10.5 per cent. Any potential for a "cure" is related to early diagnosis and adequate surgical treatment by amputation or resection.

Adult