Christian M. Ogilvie

Endoprosthetic reconstructions: Results of long-term followup of 139 patients

Our primary goal in doing this study was to determine the effect of prosthesis location, patient age, periprosthetic infection, and primary versus revision placement on endoprosthetic survival. We also examined our endoprosthetic survival rates and reasons for failure. We retrospectively studied 139 endoprosthetic reconstructions performed between 1984 and 2002, including 57 distal femur, 27 proximal femur, 26 proximal tibia, 17 proximal humerus, 4 distal humerus, 3 total scapula, 3 total femur, and 2 total humerus reconstructions. Location of reconstruction and presence of periprosthetic infection significantly affected endoprosthetic survival. Survival was not affected by patient age or primary versus revision placement. Overall, Kaplan-Meier event-free endoprosthetic survival was 86%, 80%, and 69% at 3, 5, and 10-year followup. The trend for endoprosthetic survival from best to worst was proximal femur, proximal humerus, distal femur, proximal tibia, and distal humerus. Reasons for failure included mechanical failure (eight patients), tumor recurrence (eight patients), aseptic loosening (six patients), dislocation (two patients), periprosthetic infection (two patients), and endoprosthetic malalignment (one patient). Our periprosthetic infection rate was 2.2%. The local recurrence rate in patients treated for primary malignant tumors was 6.8%, similar to previous limb-salvage and amputation studies. Overall, we have found that endoprosthetic reconstruction is a reliable limb-salvage technique. Level of Evidence: Therapeutic study, Level IV-2 (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Necrotizing soft-tissue infections.

&NA; Necrotizing fasciitis is a rare and often fatal soft-tissue infection involving the superficial fascial layers of the extremities, abdomen, or perineum. Necrotizing fasciitis typically begins with trauma; however, the inciting event may be as seemingly innocuous as a simple contusion, minor burn, or insect bite. Differentiating necrotizing infections from common soft-tissue infections, such as cellulitis and impetigo, is both challenging and critically important. A high degree of suspicion may be the most important aid in early diagnosis. Prompt diagnosis is imperative because necrotizing infections typically spread rapidly and can result in multiple-organ failure, adult respiratory distress syndrome, and death. Although group A Streptococcus is the most common bacterial isolate, a polymicrobial infection with a variety of Gram-positive, Gram-negative, aerobic, and anaerobic bacteria is more common. Orthopaedic surgeons are often the first physicians to evaluate patients with such infections and therefore need to be familiar with this potentially devastating disease and its management. Prompt diagnosis, immediate administration of broad-spectrum antibiotic coverage, and emergent aggressive surgical debridement of all compromised tissues are critical to reduce the morbidity and mortality of these rapidly progressing infections.

Intralesional curettage for grades II and III giant cell tumors of bone.

Grade III Campanacci lesions are traditionally treated with wide resections based on their postulated aggressiveness and potential for local recurrence and metastasis. The purpose of this study was to determine if there was a difference in local recurrence rates of Grade II and III lesions treated with intralesional curettage, burring, phenol cauterization, and polymethylmethacrylate application. Sixty-three patients (26 Campanacci Grade II and 37 Grade III lesions) met the inclusion criteria. No pathologic fractures, including intraarticular fractures, were included in this study. Followup averaged 108 months (range, 25–259 months). The overall local recurrence rate was 6% (4 of 63 patients), with no observed difference between Grade II and III lesions. The average Musculoskeletal Tumor Society functional score was 27.9/30 (93%). The mean range of motion of the adjacent joint was 97%. Patients with radiographic signs of osteoarthritis before treatment did not show substantial progression, and only one patient developed radiographic signs of degenerative arthritis postoperatively. Our distal metastatic rate was 3.2%. These data support the use of intralesional curettage and burring with adjuvant phenol and polymethylmethacrylate even in Grade III lesions, in the absence of pathologic fracture, regardless of the presence or extent of extraosseous extension. Level of Evidence: Therapeutic study, Level III-1 (retrospective cohort). See the Guidelines for Authors for a complete description of levels of evidence.

Clinical utility of percutaneous biopsies of musculoskeletal tumors

Percutaneous biopsies are frequently used for musculoskeletal lesions. We suspect published accuracy rates (80-97%) overestimate clinical utility. We retrospectively reviewed 120 consecutive percutaneous biopsies performed by interventional radiologists at our institution. Patients underwent core biopsy, fine-needle aspiration (FNA), or both. The biopsy interpretations were considered clinically useful if they allowed proper treatment to proceed and not useful if they were nondiagnostic or if surgical specimens disagreed with percutaneous specimen. Patients were categorized by biopsy type, tissue type, and tumor type. Ninety of 120 percutaneous biopsies were clinically useful, 27 were nondiagnostic, and three were incorrect; in these latter 30 patients we proceeded to open biopsy. Patients with both biopsies had clinically useful results (80.6%) more often than FNA or core alone(68.0% and 66.7%, respectively). Biopsies of bone lesions were clinically useful more often than those of soft tissue. Myxoid histology was associated with decreased clinical accuracy. Clinical utility was independent of tumor type. No single characteristic predicted increased probability of open biopsy. The clinical utility rate was acceptable, but below published accuracy rates. The combination of both biopsies was better than FNA alone. Myxoid findings rarely helped to guide definitive treatment. Treatment decision making requires balancing biopsy results with clinical data.Level of Evidence: Diagnostic study, level IV. See Guidelines for Authors for a complete description of levels of evidence.

Denosumab Treatment of Metastatic Giant-Cell Tumor of Bone in a 10-Year-Old Girl

Introduction Giant-cell tumor of bone (GCTB) primarily occurs in young adults between the ages of 20 and 40 years and comprises approximately 5% of primary bone tumors. Pediatric cases of GCT are even less frequent and are believed to comprise only 1.7% of all cases of GCTB. Although usually a benign tumor, GCTB frequently recurs locally after surgical resection. Approximately 3% of GCTB metastasize, primarily to the lungs; metastatic disease at presentation is uncommon. Histologically, GCTB has two cellular components: neoplastic mononuclear cells that are evenly scattered among osteoclast precursors and osteoclast-like giant cells. Radiographically, these tumors usually appear as lytic destructive lesions, often in the proximal femur or distal tibia. Clinically, patients present with pain and often have deformities at the tumor site, without constitutional symptoms. About two decades ago, the receptor activator of NF-kappaB ligand (RANKL) signaling pathway was discovered, and its importance in the regulation of bone growth and turnover became apparent. For instance, RANKL knockout mice (with absence of the ligand) demonstrate osteopetrotic bone changes as a result of impaired osteoclast differentiation and subsequent decreased bone resorption. Because denosumab inhibits RANKL (and therefore osteoclast activity), it is used in the treatment of postmenopausal osteoporosis, in which there is a state of increased bone resorption. Furthermore, RANKL is thought to participate in the growth of the tumor cells, possibly as a result of production of growth factors by osteoclast-like giant cells through a paracrine loop. Recently, a phase II study in adults with GCTs has demonstrated significant clinical response to the antiRANKL monoclonal antibody denosumab. There is also histologic confirmation of the treatment effects of denosumab on GCTs. However, we are unaware of published data regarding the safety and efficacy of this drug in pediatric patients and the impact it may have on bone growth and health.

Bipolar proximal femoral replacement prostheses for musculoskeletal neoplasms.

While bipolar proximal femoral replacement prostheses (PFRP) have become a common treatment for tumors of the proximal femur, long-term results are not specified in the literature. The objective was to determine the complication and revision rates of bipolar PFRP and compare them to historical controls of bipolar hemiarthroplasties for nontumor indications. Information was retrospectively collected on 62 patients who received bipolar PFRP with cemented diaphyseal stems for primary or metastatic disease of the proximal femur from 1981 to 2003. Mean followup was 5 years. Twelve of 62 (19%) bipolar PFRPs underwent revision. Aseptic loosening was the most common complication with six (10%) undergoing revision. None were converted to THA due to acetabular erosion. Three patients (5%) had problems with dislocation and three (5%) had deep infections. Mean MSTS functional rating was 71% of normal function. The limb salvage rate was 98% and the 5-year event-free prosthetic survival was 79%. Bipolar PFRPs were found to have higher revision, dislocation, and deep infection rates compared to bipolar hemiarthroplasty for nontumor indications, but a lower rate of conversion to THA due to acetabular erosion. Bipolar PFRPs have good long-term durability with some complications, but are able to preserve the limb and provide good function for patients.Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Necrotizing soft tissue infections of the extremities and back

Necrotizing soft tissue infections are potentially fatal infections that often involve extremities. Studies of mixed anatomic sites suggest several factors increase mortality (eg, age, medical comorbidities, laboratory values, treatment timing). We hypothesized that patients with necrotizing soft tissue infections of the extremities would have similar factors associated with mortality. We retrospectively reviewed 150 patients with necrotizing soft tissue infections of the extremities treated at San Francisco General Hospital from 1993-1997. We recorded cofactors, treatment, physical findings, radio- graphs, and laboratory findings at presentation. No cofactor or examination finding was associated with increased mortality. Compared with survivors, nonsurvivors had a higher leukocyte count, blood urea nitrogen, creatinine, potassium, partial thromboplastin time, and aspartate aminotransferase, but had lower pH and bicarbonate. Nonsurvivors did not have delays in treatment relative to survivors. Univariate analysis showed an increased risk of mortality in patients with hypotension, hypothermia, Clostridium species in the wound culture, low leukocyte count and bicarbonate levels, and elevated blood urea nitrogen, aspartate aminotransferase, creatinine, and potassium levels. Several signs of shock and organ dysfunction were associated with mortality in patients with necrotizing soft tissue infections of the extremities. The overall mortality rate (9.3%) was lower than in some other reports.Level of Evidence: Prognostic study, Level II. See the Guidelines for Authors for a complete description of the levels of evidence.

Early outcomes for malignant peripheral nerve sheath tumor treated with chemotherapy

Objectives:Malignant peripheral nerve sheath tumors (MPNST) are rare soft-tissue sarcomas with a tendency for recurrence and metastasis. Treatment using chemotherapy is controversial, but benefit with some agents has been described. This study aimed to analyze early survival outcomes using doxorubicin and ifosfamide chemotherapy for MPNST. Methods:Pathology records at our musculoskeletal tumor center were searched for patients with a new diagnosis of MPNST between 2003 and 2008. Treatment involved surgical resection, radiation, and chemotherapy with doxorubicin and ifosfamide. Ten patients met inclusion criteria, with mean age 40 years (range, 20–70). Four patients had metastatic disease on presentation. Four patients had neurofibromatosis type I (NF1). Results:Of 6 patients with nonmetastatic disease on presentation, 5 had no evidence of disease post-treatment. The sixth had positive margins after surgery and initially received no further treatment due to noncompliance. Three from this subgroup developed local recurrence, but none developed distant metastases and 1 died of disease at last follow-up. One- and 2-year disease-free survival (DFS) for this subgroup was 80% and 60%, respectively. One- and 2-year overall survival (OS) for the subgroup was 100%. Of 4 patients with metastatic disease on presentation, 2 had no evidence of disease post-treatment. One of these 2 developed local recurrence, but none from the subgroup developed new metastatic disease. Two of these 4 died of disease at last follow-up. One- and 2-year DFS for this subgroup was 100% and 50%, respectively. One- and 2-year OS was 75% and 50%, respectively. Two of the 4 patients presenting with metastatic disease had NF1. All 3 local recurrences and 2 of the 3 deaths in this study occurred in NF1 patients. Conclusions:For all patients, when combined with surgery and radiation, chemotherapy using doxorubicin and ifosfamide yielded 57% DFS and 80% OS at 2 years. NF1 patients appeared to have worse outcomes, with a statistically significantly lower DFS than non-NF1 patients. Limitations of this study include a small sample size, retrospective design, and use of different chemotherapy regimens.

Functional outcome of endoprosthetic proximal femoral replacement.

Endoprosthetic proximal femur replacement is a well-accepted method for treatment of primary bone tumors; however the functional results of treatment are not well documented. To evaluate functional outcomes, we recorded the Toronto Extremity Salvage Score and Musculoskeletal Tumor Society 1987 and 1993 scores in 29 patients, and also recorded Musculoskeletal Tumor Society scores alone in four more patients treated with endoprosthetic proximal femur replacement. The mean followup was 3 years. Twelve patients had a total hip endoprosthetic proximal femur replacement, and 21 had a bipolar hip endoprosthetic proximal femur replacement. In nine patients, the greater trochanter was attached to the femoral prosthesis. Sixteen patients had an abductor soft tissue repair, and in eight patients, no abductor repair was possible. The mean Musculoskeletal Tumor Society 1987 score was 23.2 ± 4.1 points of 35 points. The mean Musculoskeletal Tumor Society 1993 score was 67.7 ± 12.0%. The Toronto Extremity Salvage Score mean was 76.2 ± 16.2 points of 100 points. Functional scores did not differ significantly between abductor repair types. There was a trend toward less disability in patients with abductor soft tissue repair compared with patients with no abductor repair. Functional results were similar in patients receiving bipolar and total hip replacements.

Correlation spectroscopy as a probe of excitation and ionization mechanisms in the inductively coupled plasma

Abstract Correlations between intensity fluctuations in atomic and ionic emission lines were used as indicators of ionization and excitation mechanisms in the inductively coupled plasma. Ionic lines excited by charge exchange were positively correlated with neutral atom emission, while those excited by electron impact showed a negative correlation. An analog correlator was constructed to allow rapid measurement of such correlations over a broad range of wavelengths and as a function of position in the plasma. Results obtained to date suggest that charge exchange contributes significantly to the excitation and ionization of Mg, Y, Ti and V in the inductively coupled plasma.