Multiple receptor tyrosine kinases promote the in vitro phenotype of metastatic human osteosarcoma cell lines.

The survival rate for osteosarcoma patients with localized disease is 70% and only 25% for patients with metastases. Therefore, novel therapeutic and prognostic tools are needed. In this study, extensive screening and validation strategies identified Axl, EphB2, FGFR2, IGF-1R and Ret as specific receptor tyrosine kinases (RTKs) that are activated and promote the in vitro phenotype of two genetically different metastatic osteosarcoma cell lines. Initial phosphoproteomic screening identified twelve RTKs that were phosphorylated in 143B and/or LM7 metastatic human osteosarcoma cells. A small interfering RNA (siRNA) screen demonstrated that siRNA pools targeting ten of the twelve RTKS inhibited the in vitro phenotype of one or both cell lines. To validate the results, we individually tested the four siRNA duplexes that comprised each of the effective siRNA pools from the initial screen. The pattern of phenotype inhibition replicated the pattern of mRNA knockdown by the individual duplexes for seven of the ten RTKs, indicating the effects are consistent with on-target silencing. Five of those seven RTKs were further validated using independent approaches including neutralizing antibodies (IGF-1R), antisense-mediated knockdown (EphB2, FGFR2, and Ret) or small molecule inhibitors (Axl), indicating that those specific RTKs promote the in vitro behavior of metastatic osteosarcoma cell lines and are potential therapeutic targets for osteosarcoma. Immunohistochemistry demonstrated that Axl is frequently activated in osteosarcoma patient biopsy samples, further supporting our screening and validation methods to identify RTKs that may be valuable targets for novel therapies for osteosarcoma patients.

Destructive osteoarthritis after delayed diagnosis of tuberculosis.

Osteoarticular tuberculosis rarely occurs in developed countries. Initial symptoms are often overlooked and the diagnosis is frequently delayed for several months. Thus, despite available diagnostic tools and accessible treatment, destruction of affected joints remains a complication of non-vertebral osteoarticular tuberculosis even in industrialized countries. We report a patient from Cleveland, Ohio, USA, in whom the delayed diagnosis of tuberculous osteoarthritis led to severe destruction of the left knee and finally, after superinfection with Staphylococcus aureus, to an above-the-knee amputation. The epidemiology, presentation, diagnosis and treatment of nonvertebral tuberculous osteoarthritis are discussed.

Complications and functional outcomes of reconstruction with an osteoarticular allograft after intra-articular resection of the proximal aspect of the humerus.

BACKGROUND: The purpose of this study was to evaluate the functional outcome and the complications of reconstruction with an osteoarticular allograft in patients who had had intra-articular resection of the proximal aspect of the humerus. METHODS: Sixteen patients who had had intra-articular resection and reconstruction of the proximal aspect of the humerus for the treatment of a tumor between 1986 and 1996 were evaluated. The length of the resected part of the humerus ranged from eight to 27.5 centimeters. The resections were classified as either S34A or S345A resections of the shoulder girdle on the basis of the Musculoskeletal Tumor Society classification system. Reconstruction was performed with use of a nonirradiated, frozen osteoarticular allograft with intact capsular and rotator cuff attachments. Dual orthogonal dynamic compression plates were used for internal fixation of the allograft to the host bone. The oncological parameters that were evaluated included survival of the patient, local recurrence, and metastasis. The radiographic parameters included time to union, stability of the joint, fracture of the allograft, and fragmentation of the epiphysis of the allograft (subchondral collapse). Survival of the graft was assessed with Kaplan-Meier survival analysis. The modified Musculoskeletal Tumor Society evaluation system was used to assess functional outcome. RESULTS: At a median of forty-seven months (range, fourteen to 130 months) after the operation, fourteen of the patients in the study group were free of disease and two had died of disease. No patient had local recurrence or nonunion. Late complications included four fractures of the allograft and one infection of the graft. A Kaplan-Meier survival curve demonstrated a 68 percent rate of survival of the allograft at five years. Instability of the glenohumeral joint in the form of ptosis and anterior subluxation was noted in three patients, and dislocation of the glenohumeral joint was seen in eight patients. On the basis of the modified Musculoskeletal Tumor Society functional evaluation, the mean score at the most recent follow-up evaluation (at a mean of thirty-four months) was 70 percent. This score was lower than the mean score of 81 percent at a mean of fourteen months. All patients had normal manual dexterity and had mild or no pain at the most recent follow-up evaluation. However, all had restriction of recreational activities or partial disability in addition to limitations with regard to placement of the hand and the ability to lift. CONCLUSIONS: Reconstruction of the proximal aspect of the humerus with an osteoarticular allograft is an option that provides good relief of pain and preserves manual dexterity. However, in our study, function was limited by impairment of elevation of the shoulder and hand as well as by decreased strength of the shoulder. There was an extremely high rate of complications, including joint instability, fracture of the allograft, and infection of the allograft. We no longer routinely perform this reconstruction at our institution.

Observer reliability in ankle radiographic measurements.

We analyzed 50 sets of ankle radiographs to determine the interobserver and intraobserver reliability when obtaining common linear and angular measurements. The radiographs were divided into two groups: one group included 25 normal ankles, and the second group included 25 fractured ankles. Each set of radiographs was evaluated independently by four different observers on two separate occasions under controlled conditions. Six radiographic parameters were measured on all 50 sets of films: syndesmosis A, syndesmosis B, syndesmosis C, the medial clear space, and the talocrural and bimalleolar angles. On the 25 sets of fracture films, four additional measurements of fracture displacement were included: displacement of the medial malleolus (mortise), displacement of the lateral malleolus (AP and lateral), and displacement of the posterior malleolus. Reliability was evaluated with an analysis of variance intraclass correlation coefficient. Among the examiners, 9 of the 10 parameters could be measured reliably. Intraobserver reliability was found to increase with the experience of the examiner.